1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* memcontrol.c - Memory Controller
4 * Copyright IBM Corporation, 2007
5 * Author Balbir Singh <balbir@linux.vnet.ibm.com>
7 * Copyright 2007 OpenVZ SWsoft Inc
8 * Author: Pavel Emelianov <xemul@openvz.org>
11 * Copyright (C) 2009 Nokia Corporation
12 * Author: Kirill A. Shutemov
14 * Kernel Memory Controller
15 * Copyright (C) 2012 Parallels Inc. and Google Inc.
16 * Authors: Glauber Costa and Suleiman Souhlal
19 * Charge lifetime sanitation
20 * Lockless page tracking & accounting
21 * Unified hierarchy configuration model
22 * Copyright (C) 2015 Red Hat, Inc., Johannes Weiner
24 * Per memcg lru locking
25 * Copyright (C) 2020 Alibaba, Inc, Alex Shi
28 #include <linux/page_counter.h>
29 #include <linux/memcontrol.h>
30 #include <linux/cgroup.h>
31 #include <linux/pagewalk.h>
32 #include <linux/sched/mm.h>
33 #include <linux/shmem_fs.h>
34 #include <linux/hugetlb.h>
35 #include <linux/pagemap.h>
36 #include <linux/vm_event_item.h>
37 #include <linux/smp.h>
38 #include <linux/page-flags.h>
39 #include <linux/backing-dev.h>
40 #include <linux/bit_spinlock.h>
41 #include <linux/rcupdate.h>
42 #include <linux/limits.h>
43 #include <linux/export.h>
44 #include <linux/mutex.h>
45 #include <linux/rbtree.h>
46 #include <linux/slab.h>
47 #include <linux/swap.h>
48 #include <linux/swapops.h>
49 #include <linux/spinlock.h>
50 #include <linux/eventfd.h>
51 #include <linux/poll.h>
52 #include <linux/sort.h>
54 #include <linux/seq_file.h>
55 #include <linux/vmpressure.h>
56 #include <linux/mm_inline.h>
57 #include <linux/swap_cgroup.h>
58 #include <linux/cpu.h>
59 #include <linux/oom.h>
60 #include <linux/lockdep.h>
61 #include <linux/file.h>
62 #include <linux/tracehook.h>
63 #include <linux/psi.h>
64 #include <linux/seq_buf.h>
70 #include <linux/uaccess.h>
72 #include <trace/events/vmscan.h>
74 struct cgroup_subsys memory_cgrp_subsys __read_mostly;
75 EXPORT_SYMBOL(memory_cgrp_subsys);
77 struct mem_cgroup *root_mem_cgroup __read_mostly;
79 /* Active memory cgroup to use from an interrupt context */
80 DEFINE_PER_CPU(struct mem_cgroup *, int_active_memcg);
81 EXPORT_PER_CPU_SYMBOL_GPL(int_active_memcg);
83 /* Socket memory accounting disabled? */
84 static bool cgroup_memory_nosocket __ro_after_init;
86 /* Kernel memory accounting disabled? */
87 bool cgroup_memory_nokmem __ro_after_init;
89 /* Whether the swap controller is active */
90 #ifdef CONFIG_MEMCG_SWAP
91 bool cgroup_memory_noswap __ro_after_init;
93 #define cgroup_memory_noswap 1
96 #ifdef CONFIG_CGROUP_WRITEBACK
97 static DECLARE_WAIT_QUEUE_HEAD(memcg_cgwb_frn_waitq);
100 /* Whether legacy memory+swap accounting is active */
101 static bool do_memsw_account(void)
103 return !cgroup_subsys_on_dfl(memory_cgrp_subsys) && !cgroup_memory_noswap;
106 #define THRESHOLDS_EVENTS_TARGET 128
107 #define SOFTLIMIT_EVENTS_TARGET 1024
110 * Cgroups above their limits are maintained in a RB-Tree, independent of
111 * their hierarchy representation
114 struct mem_cgroup_tree_per_node {
115 struct rb_root rb_root;
116 struct rb_node *rb_rightmost;
120 struct mem_cgroup_tree {
121 struct mem_cgroup_tree_per_node *rb_tree_per_node[MAX_NUMNODES];
124 static struct mem_cgroup_tree soft_limit_tree __read_mostly;
127 struct mem_cgroup_eventfd_list {
128 struct list_head list;
129 struct eventfd_ctx *eventfd;
133 * cgroup_event represents events which userspace want to receive.
135 struct mem_cgroup_event {
137 * memcg which the event belongs to.
139 struct mem_cgroup *memcg;
141 * eventfd to signal userspace about the event.
143 struct eventfd_ctx *eventfd;
145 * Each of these stored in a list by the cgroup.
147 struct list_head list;
149 * register_event() callback will be used to add new userspace
150 * waiter for changes related to this event. Use eventfd_signal()
151 * on eventfd to send notification to userspace.
153 int (*register_event)(struct mem_cgroup *memcg,
154 struct eventfd_ctx *eventfd, const char *args);
156 * unregister_event() callback will be called when userspace closes
157 * the eventfd or on cgroup removing. This callback must be set,
158 * if you want provide notification functionality.
160 void (*unregister_event)(struct mem_cgroup *memcg,
161 struct eventfd_ctx *eventfd);
163 * All fields below needed to unregister event when
164 * userspace closes eventfd.
167 wait_queue_head_t *wqh;
168 wait_queue_entry_t wait;
169 struct work_struct remove;
172 static void mem_cgroup_threshold(struct mem_cgroup *memcg);
173 static void mem_cgroup_oom_notify(struct mem_cgroup *memcg);
175 /* Stuffs for move charges at task migration. */
177 * Types of charges to be moved.
179 #define MOVE_ANON 0x1U
180 #define MOVE_FILE 0x2U
181 #define MOVE_MASK (MOVE_ANON | MOVE_FILE)
183 /* "mc" and its members are protected by cgroup_mutex */
184 static struct move_charge_struct {
185 spinlock_t lock; /* for from, to */
186 struct mm_struct *mm;
187 struct mem_cgroup *from;
188 struct mem_cgroup *to;
190 unsigned long precharge;
191 unsigned long moved_charge;
192 unsigned long moved_swap;
193 struct task_struct *moving_task; /* a task moving charges */
194 wait_queue_head_t waitq; /* a waitq for other context */
196 .lock = __SPIN_LOCK_UNLOCKED(mc.lock),
197 .waitq = __WAIT_QUEUE_HEAD_INITIALIZER(mc.waitq),
201 * Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft
202 * limit reclaim to prevent infinite loops, if they ever occur.
204 #define MEM_CGROUP_MAX_RECLAIM_LOOPS 100
205 #define MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS 2
207 /* for encoding cft->private value on file */
216 #define MEMFILE_PRIVATE(x, val) ((x) << 16 | (val))
217 #define MEMFILE_TYPE(val) ((val) >> 16 & 0xffff)
218 #define MEMFILE_ATTR(val) ((val) & 0xffff)
219 /* Used for OOM notifier */
220 #define OOM_CONTROL (0)
223 * Iteration constructs for visiting all cgroups (under a tree). If
224 * loops are exited prematurely (break), mem_cgroup_iter_break() must
225 * be used for reference counting.
227 #define for_each_mem_cgroup_tree(iter, root) \
228 for (iter = mem_cgroup_iter(root, NULL, NULL); \
230 iter = mem_cgroup_iter(root, iter, NULL))
232 #define for_each_mem_cgroup(iter) \
233 for (iter = mem_cgroup_iter(NULL, NULL, NULL); \
235 iter = mem_cgroup_iter(NULL, iter, NULL))
237 static inline bool should_force_charge(void)
239 return tsk_is_oom_victim(current) || fatal_signal_pending(current) ||
240 (current->flags & PF_EXITING);
243 /* Some nice accessors for the vmpressure. */
244 struct vmpressure *memcg_to_vmpressure(struct mem_cgroup *memcg)
247 memcg = root_mem_cgroup;
248 return &memcg->vmpressure;
251 struct mem_cgroup *vmpressure_to_memcg(struct vmpressure *vmpr)
253 return container_of(vmpr, struct mem_cgroup, vmpressure);
256 #ifdef CONFIG_MEMCG_KMEM
257 extern spinlock_t css_set_lock;
259 bool mem_cgroup_kmem_disabled(void)
261 return cgroup_memory_nokmem;
264 static void obj_cgroup_uncharge_pages(struct obj_cgroup *objcg,
265 unsigned int nr_pages);
267 static void obj_cgroup_release(struct percpu_ref *ref)
269 struct obj_cgroup *objcg = container_of(ref, struct obj_cgroup, refcnt);
270 unsigned int nr_bytes;
271 unsigned int nr_pages;
275 * At this point all allocated objects are freed, and
276 * objcg->nr_charged_bytes can't have an arbitrary byte value.
277 * However, it can be PAGE_SIZE or (x * PAGE_SIZE).
279 * The following sequence can lead to it:
280 * 1) CPU0: objcg == stock->cached_objcg
281 * 2) CPU1: we do a small allocation (e.g. 92 bytes),
282 * PAGE_SIZE bytes are charged
283 * 3) CPU1: a process from another memcg is allocating something,
284 * the stock if flushed,
285 * objcg->nr_charged_bytes = PAGE_SIZE - 92
286 * 5) CPU0: we do release this object,
287 * 92 bytes are added to stock->nr_bytes
288 * 6) CPU0: stock is flushed,
289 * 92 bytes are added to objcg->nr_charged_bytes
291 * In the result, nr_charged_bytes == PAGE_SIZE.
292 * This page will be uncharged in obj_cgroup_release().
294 nr_bytes = atomic_read(&objcg->nr_charged_bytes);
295 WARN_ON_ONCE(nr_bytes & (PAGE_SIZE - 1));
296 nr_pages = nr_bytes >> PAGE_SHIFT;
299 obj_cgroup_uncharge_pages(objcg, nr_pages);
301 spin_lock_irqsave(&css_set_lock, flags);
302 list_del(&objcg->list);
303 spin_unlock_irqrestore(&css_set_lock, flags);
305 percpu_ref_exit(ref);
306 kfree_rcu(objcg, rcu);
309 static struct obj_cgroup *obj_cgroup_alloc(void)
311 struct obj_cgroup *objcg;
314 objcg = kzalloc(sizeof(struct obj_cgroup), GFP_KERNEL);
318 ret = percpu_ref_init(&objcg->refcnt, obj_cgroup_release, 0,
324 INIT_LIST_HEAD(&objcg->list);
328 static void memcg_reparent_objcgs(struct mem_cgroup *memcg,
329 struct mem_cgroup *parent)
331 struct obj_cgroup *objcg, *iter;
333 objcg = rcu_replace_pointer(memcg->objcg, NULL, true);
335 spin_lock_irq(&css_set_lock);
337 /* 1) Ready to reparent active objcg. */
338 list_add(&objcg->list, &memcg->objcg_list);
339 /* 2) Reparent active objcg and already reparented objcgs to parent. */
340 list_for_each_entry(iter, &memcg->objcg_list, list)
341 WRITE_ONCE(iter->memcg, parent);
342 /* 3) Move already reparented objcgs to the parent's list */
343 list_splice(&memcg->objcg_list, &parent->objcg_list);
345 spin_unlock_irq(&css_set_lock);
347 percpu_ref_kill(&objcg->refcnt);
351 * This will be used as a shrinker list's index.
352 * The main reason for not using cgroup id for this:
353 * this works better in sparse environments, where we have a lot of memcgs,
354 * but only a few kmem-limited. Or also, if we have, for instance, 200
355 * memcgs, and none but the 200th is kmem-limited, we'd have to have a
356 * 200 entry array for that.
358 * The current size of the caches array is stored in memcg_nr_cache_ids. It
359 * will double each time we have to increase it.
361 static DEFINE_IDA(memcg_cache_ida);
362 int memcg_nr_cache_ids;
364 /* Protects memcg_nr_cache_ids */
365 static DECLARE_RWSEM(memcg_cache_ids_sem);
367 void memcg_get_cache_ids(void)
369 down_read(&memcg_cache_ids_sem);
372 void memcg_put_cache_ids(void)
374 up_read(&memcg_cache_ids_sem);
378 * MIN_SIZE is different than 1, because we would like to avoid going through
379 * the alloc/free process all the time. In a small machine, 4 kmem-limited
380 * cgroups is a reasonable guess. In the future, it could be a parameter or
381 * tunable, but that is strictly not necessary.
383 * MAX_SIZE should be as large as the number of cgrp_ids. Ideally, we could get
384 * this constant directly from cgroup, but it is understandable that this is
385 * better kept as an internal representation in cgroup.c. In any case, the
386 * cgrp_id space is not getting any smaller, and we don't have to necessarily
387 * increase ours as well if it increases.
389 #define MEMCG_CACHES_MIN_SIZE 4
390 #define MEMCG_CACHES_MAX_SIZE MEM_CGROUP_ID_MAX
393 * A lot of the calls to the cache allocation functions are expected to be
394 * inlined by the compiler. Since the calls to memcg_slab_pre_alloc_hook() are
395 * conditional to this static branch, we'll have to allow modules that does
396 * kmem_cache_alloc and the such to see this symbol as well
398 DEFINE_STATIC_KEY_FALSE(memcg_kmem_enabled_key);
399 EXPORT_SYMBOL(memcg_kmem_enabled_key);
403 * mem_cgroup_css_from_page - css of the memcg associated with a page
404 * @page: page of interest
406 * If memcg is bound to the default hierarchy, css of the memcg associated
407 * with @page is returned. The returned css remains associated with @page
408 * until it is released.
410 * If memcg is bound to a traditional hierarchy, the css of root_mem_cgroup
413 struct cgroup_subsys_state *mem_cgroup_css_from_page(struct page *page)
415 struct mem_cgroup *memcg;
417 memcg = page_memcg(page);
419 if (!memcg || !cgroup_subsys_on_dfl(memory_cgrp_subsys))
420 memcg = root_mem_cgroup;
426 * page_cgroup_ino - return inode number of the memcg a page is charged to
429 * Look up the closest online ancestor of the memory cgroup @page is charged to
430 * and return its inode number or 0 if @page is not charged to any cgroup. It
431 * is safe to call this function without holding a reference to @page.
433 * Note, this function is inherently racy, because there is nothing to prevent
434 * the cgroup inode from getting torn down and potentially reallocated a moment
435 * after page_cgroup_ino() returns, so it only should be used by callers that
436 * do not care (such as procfs interfaces).
438 ino_t page_cgroup_ino(struct page *page)
440 struct mem_cgroup *memcg;
441 unsigned long ino = 0;
444 memcg = page_memcg_check(page);
446 while (memcg && !(memcg->css.flags & CSS_ONLINE))
447 memcg = parent_mem_cgroup(memcg);
449 ino = cgroup_ino(memcg->css.cgroup);
454 static struct mem_cgroup_per_node *
455 mem_cgroup_page_nodeinfo(struct mem_cgroup *memcg, struct page *page)
457 int nid = page_to_nid(page);
459 return memcg->nodeinfo[nid];
462 static struct mem_cgroup_tree_per_node *
463 soft_limit_tree_node(int nid)
465 return soft_limit_tree.rb_tree_per_node[nid];
468 static struct mem_cgroup_tree_per_node *
469 soft_limit_tree_from_page(struct page *page)
471 int nid = page_to_nid(page);
473 return soft_limit_tree.rb_tree_per_node[nid];
476 static void __mem_cgroup_insert_exceeded(struct mem_cgroup_per_node *mz,
477 struct mem_cgroup_tree_per_node *mctz,
478 unsigned long new_usage_in_excess)
480 struct rb_node **p = &mctz->rb_root.rb_node;
481 struct rb_node *parent = NULL;
482 struct mem_cgroup_per_node *mz_node;
483 bool rightmost = true;
488 mz->usage_in_excess = new_usage_in_excess;
489 if (!mz->usage_in_excess)
493 mz_node = rb_entry(parent, struct mem_cgroup_per_node,
495 if (mz->usage_in_excess < mz_node->usage_in_excess) {
504 mctz->rb_rightmost = &mz->tree_node;
506 rb_link_node(&mz->tree_node, parent, p);
507 rb_insert_color(&mz->tree_node, &mctz->rb_root);
511 static void __mem_cgroup_remove_exceeded(struct mem_cgroup_per_node *mz,
512 struct mem_cgroup_tree_per_node *mctz)
517 if (&mz->tree_node == mctz->rb_rightmost)
518 mctz->rb_rightmost = rb_prev(&mz->tree_node);
520 rb_erase(&mz->tree_node, &mctz->rb_root);
524 static void mem_cgroup_remove_exceeded(struct mem_cgroup_per_node *mz,
525 struct mem_cgroup_tree_per_node *mctz)
529 spin_lock_irqsave(&mctz->lock, flags);
530 __mem_cgroup_remove_exceeded(mz, mctz);
531 spin_unlock_irqrestore(&mctz->lock, flags);
534 static unsigned long soft_limit_excess(struct mem_cgroup *memcg)
536 unsigned long nr_pages = page_counter_read(&memcg->memory);
537 unsigned long soft_limit = READ_ONCE(memcg->soft_limit);
538 unsigned long excess = 0;
540 if (nr_pages > soft_limit)
541 excess = nr_pages - soft_limit;
546 static void mem_cgroup_update_tree(struct mem_cgroup *memcg, struct page *page)
548 unsigned long excess;
549 struct mem_cgroup_per_node *mz;
550 struct mem_cgroup_tree_per_node *mctz;
552 mctz = soft_limit_tree_from_page(page);
556 * Necessary to update all ancestors when hierarchy is used.
557 * because their event counter is not touched.
559 for (; memcg; memcg = parent_mem_cgroup(memcg)) {
560 mz = mem_cgroup_page_nodeinfo(memcg, page);
561 excess = soft_limit_excess(memcg);
563 * We have to update the tree if mz is on RB-tree or
564 * mem is over its softlimit.
566 if (excess || mz->on_tree) {
569 spin_lock_irqsave(&mctz->lock, flags);
570 /* if on-tree, remove it */
572 __mem_cgroup_remove_exceeded(mz, mctz);
574 * Insert again. mz->usage_in_excess will be updated.
575 * If excess is 0, no tree ops.
577 __mem_cgroup_insert_exceeded(mz, mctz, excess);
578 spin_unlock_irqrestore(&mctz->lock, flags);
583 static void mem_cgroup_remove_from_trees(struct mem_cgroup *memcg)
585 struct mem_cgroup_tree_per_node *mctz;
586 struct mem_cgroup_per_node *mz;
590 mz = memcg->nodeinfo[nid];
591 mctz = soft_limit_tree_node(nid);
593 mem_cgroup_remove_exceeded(mz, mctz);
597 static struct mem_cgroup_per_node *
598 __mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_node *mctz)
600 struct mem_cgroup_per_node *mz;
604 if (!mctz->rb_rightmost)
605 goto done; /* Nothing to reclaim from */
607 mz = rb_entry(mctz->rb_rightmost,
608 struct mem_cgroup_per_node, tree_node);
610 * Remove the node now but someone else can add it back,
611 * we will to add it back at the end of reclaim to its correct
612 * position in the tree.
614 __mem_cgroup_remove_exceeded(mz, mctz);
615 if (!soft_limit_excess(mz->memcg) ||
616 !css_tryget(&mz->memcg->css))
622 static struct mem_cgroup_per_node *
623 mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_node *mctz)
625 struct mem_cgroup_per_node *mz;
627 spin_lock_irq(&mctz->lock);
628 mz = __mem_cgroup_largest_soft_limit_node(mctz);
629 spin_unlock_irq(&mctz->lock);
634 * memcg and lruvec stats flushing
636 * Many codepaths leading to stats update or read are performance sensitive and
637 * adding stats flushing in such codepaths is not desirable. So, to optimize the
638 * flushing the kernel does:
640 * 1) Periodically and asynchronously flush the stats every 2 seconds to not let
641 * rstat update tree grow unbounded.
643 * 2) Flush the stats synchronously on reader side only when there are more than
644 * (MEMCG_CHARGE_BATCH * nr_cpus) update events. Though this optimization
645 * will let stats be out of sync by atmost (MEMCG_CHARGE_BATCH * nr_cpus) but
646 * only for 2 seconds due to (1).
648 static void flush_memcg_stats_dwork(struct work_struct *w);
649 static DECLARE_DEFERRABLE_WORK(stats_flush_dwork, flush_memcg_stats_dwork);
650 static DEFINE_SPINLOCK(stats_flush_lock);
651 static DEFINE_PER_CPU(unsigned int, stats_updates);
652 static atomic_t stats_flush_threshold = ATOMIC_INIT(0);
654 static inline void memcg_rstat_updated(struct mem_cgroup *memcg)
656 cgroup_rstat_updated(memcg->css.cgroup, smp_processor_id());
657 if (!(__this_cpu_inc_return(stats_updates) % MEMCG_CHARGE_BATCH))
658 atomic_inc(&stats_flush_threshold);
661 static void __mem_cgroup_flush_stats(void)
665 if (!spin_trylock_irqsave(&stats_flush_lock, flag))
668 cgroup_rstat_flush_irqsafe(root_mem_cgroup->css.cgroup);
669 atomic_set(&stats_flush_threshold, 0);
670 spin_unlock_irqrestore(&stats_flush_lock, flag);
673 void mem_cgroup_flush_stats(void)
675 if (atomic_read(&stats_flush_threshold) > num_online_cpus())
676 __mem_cgroup_flush_stats();
679 static void flush_memcg_stats_dwork(struct work_struct *w)
681 mem_cgroup_flush_stats();
682 queue_delayed_work(system_unbound_wq, &stats_flush_dwork, 2UL*HZ);
686 * __mod_memcg_state - update cgroup memory statistics
687 * @memcg: the memory cgroup
688 * @idx: the stat item - can be enum memcg_stat_item or enum node_stat_item
689 * @val: delta to add to the counter, can be negative
691 void __mod_memcg_state(struct mem_cgroup *memcg, int idx, int val)
693 if (mem_cgroup_disabled())
696 __this_cpu_add(memcg->vmstats_percpu->state[idx], val);
697 memcg_rstat_updated(memcg);
700 /* idx can be of type enum memcg_stat_item or node_stat_item. */
701 static unsigned long memcg_page_state_local(struct mem_cgroup *memcg, int idx)
706 for_each_possible_cpu(cpu)
707 x += per_cpu(memcg->vmstats_percpu->state[idx], cpu);
715 void __mod_memcg_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx,
718 struct mem_cgroup_per_node *pn;
719 struct mem_cgroup *memcg;
721 pn = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
725 __this_cpu_add(memcg->vmstats_percpu->state[idx], val);
728 __this_cpu_add(pn->lruvec_stats_percpu->state[idx], val);
730 memcg_rstat_updated(memcg);
734 * __mod_lruvec_state - update lruvec memory statistics
735 * @lruvec: the lruvec
736 * @idx: the stat item
737 * @val: delta to add to the counter, can be negative
739 * The lruvec is the intersection of the NUMA node and a cgroup. This
740 * function updates the all three counters that are affected by a
741 * change of state at this level: per-node, per-cgroup, per-lruvec.
743 void __mod_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx,
747 __mod_node_page_state(lruvec_pgdat(lruvec), idx, val);
749 /* Update memcg and lruvec */
750 if (!mem_cgroup_disabled())
751 __mod_memcg_lruvec_state(lruvec, idx, val);
754 void __mod_lruvec_page_state(struct page *page, enum node_stat_item idx,
757 struct page *head = compound_head(page); /* rmap on tail pages */
758 struct mem_cgroup *memcg;
759 pg_data_t *pgdat = page_pgdat(page);
760 struct lruvec *lruvec;
763 memcg = page_memcg(head);
764 /* Untracked pages have no memcg, no lruvec. Update only the node */
767 __mod_node_page_state(pgdat, idx, val);
771 lruvec = mem_cgroup_lruvec(memcg, pgdat);
772 __mod_lruvec_state(lruvec, idx, val);
775 EXPORT_SYMBOL(__mod_lruvec_page_state);
777 void __mod_lruvec_kmem_state(void *p, enum node_stat_item idx, int val)
779 pg_data_t *pgdat = page_pgdat(virt_to_page(p));
780 struct mem_cgroup *memcg;
781 struct lruvec *lruvec;
784 memcg = mem_cgroup_from_obj(p);
787 * Untracked pages have no memcg, no lruvec. Update only the
788 * node. If we reparent the slab objects to the root memcg,
789 * when we free the slab object, we need to update the per-memcg
790 * vmstats to keep it correct for the root memcg.
793 __mod_node_page_state(pgdat, idx, val);
795 lruvec = mem_cgroup_lruvec(memcg, pgdat);
796 __mod_lruvec_state(lruvec, idx, val);
802 * mod_objcg_mlstate() may be called with irq enabled, so
803 * mod_memcg_lruvec_state() should be used.
805 static inline void mod_objcg_mlstate(struct obj_cgroup *objcg,
806 struct pglist_data *pgdat,
807 enum node_stat_item idx, int nr)
809 struct mem_cgroup *memcg;
810 struct lruvec *lruvec;
813 memcg = obj_cgroup_memcg(objcg);
814 lruvec = mem_cgroup_lruvec(memcg, pgdat);
815 mod_memcg_lruvec_state(lruvec, idx, nr);
820 * __count_memcg_events - account VM events in a cgroup
821 * @memcg: the memory cgroup
822 * @idx: the event item
823 * @count: the number of events that occurred
825 void __count_memcg_events(struct mem_cgroup *memcg, enum vm_event_item idx,
828 if (mem_cgroup_disabled())
831 __this_cpu_add(memcg->vmstats_percpu->events[idx], count);
832 memcg_rstat_updated(memcg);
835 static unsigned long memcg_events(struct mem_cgroup *memcg, int event)
837 return READ_ONCE(memcg->vmstats.events[event]);
840 static unsigned long memcg_events_local(struct mem_cgroup *memcg, int event)
845 for_each_possible_cpu(cpu)
846 x += per_cpu(memcg->vmstats_percpu->events[event], cpu);
850 static void mem_cgroup_charge_statistics(struct mem_cgroup *memcg,
854 /* pagein of a big page is an event. So, ignore page size */
856 __count_memcg_events(memcg, PGPGIN, 1);
858 __count_memcg_events(memcg, PGPGOUT, 1);
859 nr_pages = -nr_pages; /* for event */
862 __this_cpu_add(memcg->vmstats_percpu->nr_page_events, nr_pages);
865 static bool mem_cgroup_event_ratelimit(struct mem_cgroup *memcg,
866 enum mem_cgroup_events_target target)
868 unsigned long val, next;
870 val = __this_cpu_read(memcg->vmstats_percpu->nr_page_events);
871 next = __this_cpu_read(memcg->vmstats_percpu->targets[target]);
872 /* from time_after() in jiffies.h */
873 if ((long)(next - val) < 0) {
875 case MEM_CGROUP_TARGET_THRESH:
876 next = val + THRESHOLDS_EVENTS_TARGET;
878 case MEM_CGROUP_TARGET_SOFTLIMIT:
879 next = val + SOFTLIMIT_EVENTS_TARGET;
884 __this_cpu_write(memcg->vmstats_percpu->targets[target], next);
891 * Check events in order.
894 static void memcg_check_events(struct mem_cgroup *memcg, struct page *page)
896 /* threshold event is triggered in finer grain than soft limit */
897 if (unlikely(mem_cgroup_event_ratelimit(memcg,
898 MEM_CGROUP_TARGET_THRESH))) {
901 do_softlimit = mem_cgroup_event_ratelimit(memcg,
902 MEM_CGROUP_TARGET_SOFTLIMIT);
903 mem_cgroup_threshold(memcg);
904 if (unlikely(do_softlimit))
905 mem_cgroup_update_tree(memcg, page);
909 struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
912 * mm_update_next_owner() may clear mm->owner to NULL
913 * if it races with swapoff, page migration, etc.
914 * So this can be called with p == NULL.
919 return mem_cgroup_from_css(task_css(p, memory_cgrp_id));
921 EXPORT_SYMBOL(mem_cgroup_from_task);
923 static __always_inline struct mem_cgroup *active_memcg(void)
926 return this_cpu_read(int_active_memcg);
928 return current->active_memcg;
932 * get_mem_cgroup_from_mm: Obtain a reference on given mm_struct's memcg.
933 * @mm: mm from which memcg should be extracted. It can be NULL.
935 * Obtain a reference on mm->memcg and returns it if successful. If mm
936 * is NULL, then the memcg is chosen as follows:
937 * 1) The active memcg, if set.
938 * 2) current->mm->memcg, if available
940 * If mem_cgroup is disabled, NULL is returned.
942 struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm)
944 struct mem_cgroup *memcg;
946 if (mem_cgroup_disabled())
950 * Page cache insertions can happen without an
951 * actual mm context, e.g. during disk probing
952 * on boot, loopback IO, acct() writes etc.
954 * No need to css_get on root memcg as the reference
955 * counting is disabled on the root level in the
956 * cgroup core. See CSS_NO_REF.
959 memcg = active_memcg();
960 if (unlikely(memcg)) {
961 /* remote memcg must hold a ref */
962 css_get(&memcg->css);
967 return root_mem_cgroup;
972 memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
973 if (unlikely(!memcg))
974 memcg = root_mem_cgroup;
975 } while (!css_tryget(&memcg->css));
979 EXPORT_SYMBOL(get_mem_cgroup_from_mm);
981 static __always_inline bool memcg_kmem_bypass(void)
983 /* Allow remote memcg charging from any context. */
984 if (unlikely(active_memcg()))
987 /* Memcg to charge can't be determined. */
988 if (!in_task() || !current->mm || (current->flags & PF_KTHREAD))
995 * mem_cgroup_iter - iterate over memory cgroup hierarchy
996 * @root: hierarchy root
997 * @prev: previously returned memcg, NULL on first invocation
998 * @reclaim: cookie for shared reclaim walks, NULL for full walks
1000 * Returns references to children of the hierarchy below @root, or
1001 * @root itself, or %NULL after a full round-trip.
1003 * Caller must pass the return value in @prev on subsequent
1004 * invocations for reference counting, or use mem_cgroup_iter_break()
1005 * to cancel a hierarchy walk before the round-trip is complete.
1007 * Reclaimers can specify a node in @reclaim to divide up the memcgs
1008 * in the hierarchy among all concurrent reclaimers operating on the
1011 struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root,
1012 struct mem_cgroup *prev,
1013 struct mem_cgroup_reclaim_cookie *reclaim)
1015 struct mem_cgroup_reclaim_iter *iter;
1016 struct cgroup_subsys_state *css = NULL;
1017 struct mem_cgroup *memcg = NULL;
1018 struct mem_cgroup *pos = NULL;
1020 if (mem_cgroup_disabled())
1024 root = root_mem_cgroup;
1026 if (prev && !reclaim)
1032 struct mem_cgroup_per_node *mz;
1034 mz = root->nodeinfo[reclaim->pgdat->node_id];
1037 if (prev && reclaim->generation != iter->generation)
1041 pos = READ_ONCE(iter->position);
1042 if (!pos || css_tryget(&pos->css))
1045 * css reference reached zero, so iter->position will
1046 * be cleared by ->css_released. However, we should not
1047 * rely on this happening soon, because ->css_released
1048 * is called from a work queue, and by busy-waiting we
1049 * might block it. So we clear iter->position right
1052 (void)cmpxchg(&iter->position, pos, NULL);
1060 css = css_next_descendant_pre(css, &root->css);
1063 * Reclaimers share the hierarchy walk, and a
1064 * new one might jump in right at the end of
1065 * the hierarchy - make sure they see at least
1066 * one group and restart from the beginning.
1074 * Verify the css and acquire a reference. The root
1075 * is provided by the caller, so we know it's alive
1076 * and kicking, and don't take an extra reference.
1078 memcg = mem_cgroup_from_css(css);
1080 if (css == &root->css)
1083 if (css_tryget(css))
1091 * The position could have already been updated by a competing
1092 * thread, so check that the value hasn't changed since we read
1093 * it to avoid reclaiming from the same cgroup twice.
1095 (void)cmpxchg(&iter->position, pos, memcg);
1103 reclaim->generation = iter->generation;
1108 if (prev && prev != root)
1109 css_put(&prev->css);
1115 * mem_cgroup_iter_break - abort a hierarchy walk prematurely
1116 * @root: hierarchy root
1117 * @prev: last visited hierarchy member as returned by mem_cgroup_iter()
1119 void mem_cgroup_iter_break(struct mem_cgroup *root,
1120 struct mem_cgroup *prev)
1123 root = root_mem_cgroup;
1124 if (prev && prev != root)
1125 css_put(&prev->css);
1128 static void __invalidate_reclaim_iterators(struct mem_cgroup *from,
1129 struct mem_cgroup *dead_memcg)
1131 struct mem_cgroup_reclaim_iter *iter;
1132 struct mem_cgroup_per_node *mz;
1135 for_each_node(nid) {
1136 mz = from->nodeinfo[nid];
1138 cmpxchg(&iter->position, dead_memcg, NULL);
1142 static void invalidate_reclaim_iterators(struct mem_cgroup *dead_memcg)
1144 struct mem_cgroup *memcg = dead_memcg;
1145 struct mem_cgroup *last;
1148 __invalidate_reclaim_iterators(memcg, dead_memcg);
1150 } while ((memcg = parent_mem_cgroup(memcg)));
1153 * When cgruop1 non-hierarchy mode is used,
1154 * parent_mem_cgroup() does not walk all the way up to the
1155 * cgroup root (root_mem_cgroup). So we have to handle
1156 * dead_memcg from cgroup root separately.
1158 if (last != root_mem_cgroup)
1159 __invalidate_reclaim_iterators(root_mem_cgroup,
1164 * mem_cgroup_scan_tasks - iterate over tasks of a memory cgroup hierarchy
1165 * @memcg: hierarchy root
1166 * @fn: function to call for each task
1167 * @arg: argument passed to @fn
1169 * This function iterates over tasks attached to @memcg or to any of its
1170 * descendants and calls @fn for each task. If @fn returns a non-zero
1171 * value, the function breaks the iteration loop and returns the value.
1172 * Otherwise, it will iterate over all tasks and return 0.
1174 * This function must not be called for the root memory cgroup.
1176 int mem_cgroup_scan_tasks(struct mem_cgroup *memcg,
1177 int (*fn)(struct task_struct *, void *), void *arg)
1179 struct mem_cgroup *iter;
1182 BUG_ON(memcg == root_mem_cgroup);
1184 for_each_mem_cgroup_tree(iter, memcg) {
1185 struct css_task_iter it;
1186 struct task_struct *task;
1188 css_task_iter_start(&iter->css, CSS_TASK_ITER_PROCS, &it);
1189 while (!ret && (task = css_task_iter_next(&it)))
1190 ret = fn(task, arg);
1191 css_task_iter_end(&it);
1193 mem_cgroup_iter_break(memcg, iter);
1200 #ifdef CONFIG_DEBUG_VM
1201 void lruvec_memcg_debug(struct lruvec *lruvec, struct page *page)
1203 struct mem_cgroup *memcg;
1205 if (mem_cgroup_disabled())
1208 memcg = page_memcg(page);
1211 VM_BUG_ON_PAGE(lruvec_memcg(lruvec) != root_mem_cgroup, page);
1213 VM_BUG_ON_PAGE(lruvec_memcg(lruvec) != memcg, page);
1218 * lock_page_lruvec - lock and return lruvec for a given page.
1221 * These functions are safe to use under any of the following conditions:
1224 * - lock_page_memcg()
1225 * - page->_refcount is zero
1227 struct lruvec *lock_page_lruvec(struct page *page)
1229 struct lruvec *lruvec;
1231 lruvec = mem_cgroup_page_lruvec(page);
1232 spin_lock(&lruvec->lru_lock);
1234 lruvec_memcg_debug(lruvec, page);
1239 struct lruvec *lock_page_lruvec_irq(struct page *page)
1241 struct lruvec *lruvec;
1243 lruvec = mem_cgroup_page_lruvec(page);
1244 spin_lock_irq(&lruvec->lru_lock);
1246 lruvec_memcg_debug(lruvec, page);
1251 struct lruvec *lock_page_lruvec_irqsave(struct page *page, unsigned long *flags)
1253 struct lruvec *lruvec;
1255 lruvec = mem_cgroup_page_lruvec(page);
1256 spin_lock_irqsave(&lruvec->lru_lock, *flags);
1258 lruvec_memcg_debug(lruvec, page);
1264 * mem_cgroup_update_lru_size - account for adding or removing an lru page
1265 * @lruvec: mem_cgroup per zone lru vector
1266 * @lru: index of lru list the page is sitting on
1267 * @zid: zone id of the accounted pages
1268 * @nr_pages: positive when adding or negative when removing
1270 * This function must be called under lru_lock, just before a page is added
1271 * to or just after a page is removed from an lru list (that ordering being
1272 * so as to allow it to check that lru_size 0 is consistent with list_empty).
1274 void mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru,
1275 int zid, int nr_pages)
1277 struct mem_cgroup_per_node *mz;
1278 unsigned long *lru_size;
1281 if (mem_cgroup_disabled())
1284 mz = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
1285 lru_size = &mz->lru_zone_size[zid][lru];
1288 *lru_size += nr_pages;
1291 if (WARN_ONCE(size < 0,
1292 "%s(%p, %d, %d): lru_size %ld\n",
1293 __func__, lruvec, lru, nr_pages, size)) {
1299 *lru_size += nr_pages;
1303 * mem_cgroup_margin - calculate chargeable space of a memory cgroup
1304 * @memcg: the memory cgroup
1306 * Returns the maximum amount of memory @mem can be charged with, in
1309 static unsigned long mem_cgroup_margin(struct mem_cgroup *memcg)
1311 unsigned long margin = 0;
1312 unsigned long count;
1313 unsigned long limit;
1315 count = page_counter_read(&memcg->memory);
1316 limit = READ_ONCE(memcg->memory.max);
1318 margin = limit - count;
1320 if (do_memsw_account()) {
1321 count = page_counter_read(&memcg->memsw);
1322 limit = READ_ONCE(memcg->memsw.max);
1324 margin = min(margin, limit - count);
1333 * A routine for checking "mem" is under move_account() or not.
1335 * Checking a cgroup is mc.from or mc.to or under hierarchy of
1336 * moving cgroups. This is for waiting at high-memory pressure
1339 static bool mem_cgroup_under_move(struct mem_cgroup *memcg)
1341 struct mem_cgroup *from;
1342 struct mem_cgroup *to;
1345 * Unlike task_move routines, we access mc.to, mc.from not under
1346 * mutual exclusion by cgroup_mutex. Here, we take spinlock instead.
1348 spin_lock(&mc.lock);
1354 ret = mem_cgroup_is_descendant(from, memcg) ||
1355 mem_cgroup_is_descendant(to, memcg);
1357 spin_unlock(&mc.lock);
1361 static bool mem_cgroup_wait_acct_move(struct mem_cgroup *memcg)
1363 if (mc.moving_task && current != mc.moving_task) {
1364 if (mem_cgroup_under_move(memcg)) {
1366 prepare_to_wait(&mc.waitq, &wait, TASK_INTERRUPTIBLE);
1367 /* moving charge context might have finished. */
1370 finish_wait(&mc.waitq, &wait);
1377 struct memory_stat {
1382 static const struct memory_stat memory_stats[] = {
1383 { "anon", NR_ANON_MAPPED },
1384 { "file", NR_FILE_PAGES },
1385 { "kernel_stack", NR_KERNEL_STACK_KB },
1386 { "pagetables", NR_PAGETABLE },
1387 { "percpu", MEMCG_PERCPU_B },
1388 { "sock", MEMCG_SOCK },
1389 { "shmem", NR_SHMEM },
1390 { "file_mapped", NR_FILE_MAPPED },
1391 { "file_dirty", NR_FILE_DIRTY },
1392 { "file_writeback", NR_WRITEBACK },
1394 { "swapcached", NR_SWAPCACHE },
1396 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
1397 { "anon_thp", NR_ANON_THPS },
1398 { "file_thp", NR_FILE_THPS },
1399 { "shmem_thp", NR_SHMEM_THPS },
1401 { "inactive_anon", NR_INACTIVE_ANON },
1402 { "active_anon", NR_ACTIVE_ANON },
1403 { "inactive_file", NR_INACTIVE_FILE },
1404 { "active_file", NR_ACTIVE_FILE },
1405 { "unevictable", NR_UNEVICTABLE },
1406 { "slab_reclaimable", NR_SLAB_RECLAIMABLE_B },
1407 { "slab_unreclaimable", NR_SLAB_UNRECLAIMABLE_B },
1409 /* The memory events */
1410 { "workingset_refault_anon", WORKINGSET_REFAULT_ANON },
1411 { "workingset_refault_file", WORKINGSET_REFAULT_FILE },
1412 { "workingset_activate_anon", WORKINGSET_ACTIVATE_ANON },
1413 { "workingset_activate_file", WORKINGSET_ACTIVATE_FILE },
1414 { "workingset_restore_anon", WORKINGSET_RESTORE_ANON },
1415 { "workingset_restore_file", WORKINGSET_RESTORE_FILE },
1416 { "workingset_nodereclaim", WORKINGSET_NODERECLAIM },
1419 /* Translate stat items to the correct unit for memory.stat output */
1420 static int memcg_page_state_unit(int item)
1423 case MEMCG_PERCPU_B:
1424 case NR_SLAB_RECLAIMABLE_B:
1425 case NR_SLAB_UNRECLAIMABLE_B:
1426 case WORKINGSET_REFAULT_ANON:
1427 case WORKINGSET_REFAULT_FILE:
1428 case WORKINGSET_ACTIVATE_ANON:
1429 case WORKINGSET_ACTIVATE_FILE:
1430 case WORKINGSET_RESTORE_ANON:
1431 case WORKINGSET_RESTORE_FILE:
1432 case WORKINGSET_NODERECLAIM:
1434 case NR_KERNEL_STACK_KB:
1441 static inline unsigned long memcg_page_state_output(struct mem_cgroup *memcg,
1444 return memcg_page_state(memcg, item) * memcg_page_state_unit(item);
1447 static char *memory_stat_format(struct mem_cgroup *memcg)
1452 seq_buf_init(&s, kmalloc(PAGE_SIZE, GFP_KERNEL), PAGE_SIZE);
1457 * Provide statistics on the state of the memory subsystem as
1458 * well as cumulative event counters that show past behavior.
1460 * This list is ordered following a combination of these gradients:
1461 * 1) generic big picture -> specifics and details
1462 * 2) reflecting userspace activity -> reflecting kernel heuristics
1464 * Current memory state:
1466 mem_cgroup_flush_stats();
1468 for (i = 0; i < ARRAY_SIZE(memory_stats); i++) {
1471 size = memcg_page_state_output(memcg, memory_stats[i].idx);
1472 seq_buf_printf(&s, "%s %llu\n", memory_stats[i].name, size);
1474 if (unlikely(memory_stats[i].idx == NR_SLAB_UNRECLAIMABLE_B)) {
1475 size += memcg_page_state_output(memcg,
1476 NR_SLAB_RECLAIMABLE_B);
1477 seq_buf_printf(&s, "slab %llu\n", size);
1481 /* Accumulated memory events */
1483 seq_buf_printf(&s, "%s %lu\n", vm_event_name(PGFAULT),
1484 memcg_events(memcg, PGFAULT));
1485 seq_buf_printf(&s, "%s %lu\n", vm_event_name(PGMAJFAULT),
1486 memcg_events(memcg, PGMAJFAULT));
1487 seq_buf_printf(&s, "%s %lu\n", vm_event_name(PGREFILL),
1488 memcg_events(memcg, PGREFILL));
1489 seq_buf_printf(&s, "pgscan %lu\n",
1490 memcg_events(memcg, PGSCAN_KSWAPD) +
1491 memcg_events(memcg, PGSCAN_DIRECT));
1492 seq_buf_printf(&s, "pgsteal %lu\n",
1493 memcg_events(memcg, PGSTEAL_KSWAPD) +
1494 memcg_events(memcg, PGSTEAL_DIRECT));
1495 seq_buf_printf(&s, "%s %lu\n", vm_event_name(PGACTIVATE),
1496 memcg_events(memcg, PGACTIVATE));
1497 seq_buf_printf(&s, "%s %lu\n", vm_event_name(PGDEACTIVATE),
1498 memcg_events(memcg, PGDEACTIVATE));
1499 seq_buf_printf(&s, "%s %lu\n", vm_event_name(PGLAZYFREE),
1500 memcg_events(memcg, PGLAZYFREE));
1501 seq_buf_printf(&s, "%s %lu\n", vm_event_name(PGLAZYFREED),
1502 memcg_events(memcg, PGLAZYFREED));
1504 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
1505 seq_buf_printf(&s, "%s %lu\n", vm_event_name(THP_FAULT_ALLOC),
1506 memcg_events(memcg, THP_FAULT_ALLOC));
1507 seq_buf_printf(&s, "%s %lu\n", vm_event_name(THP_COLLAPSE_ALLOC),
1508 memcg_events(memcg, THP_COLLAPSE_ALLOC));
1509 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
1511 /* The above should easily fit into one page */
1512 WARN_ON_ONCE(seq_buf_has_overflowed(&s));
1517 #define K(x) ((x) << (PAGE_SHIFT-10))
1519 * mem_cgroup_print_oom_context: Print OOM information relevant to
1520 * memory controller.
1521 * @memcg: The memory cgroup that went over limit
1522 * @p: Task that is going to be killed
1524 * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is
1527 void mem_cgroup_print_oom_context(struct mem_cgroup *memcg, struct task_struct *p)
1532 pr_cont(",oom_memcg=");
1533 pr_cont_cgroup_path(memcg->css.cgroup);
1535 pr_cont(",global_oom");
1537 pr_cont(",task_memcg=");
1538 pr_cont_cgroup_path(task_cgroup(p, memory_cgrp_id));
1544 * mem_cgroup_print_oom_meminfo: Print OOM memory information relevant to
1545 * memory controller.
1546 * @memcg: The memory cgroup that went over limit
1548 void mem_cgroup_print_oom_meminfo(struct mem_cgroup *memcg)
1552 pr_info("memory: usage %llukB, limit %llukB, failcnt %lu\n",
1553 K((u64)page_counter_read(&memcg->memory)),
1554 K((u64)READ_ONCE(memcg->memory.max)), memcg->memory.failcnt);
1555 if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
1556 pr_info("swap: usage %llukB, limit %llukB, failcnt %lu\n",
1557 K((u64)page_counter_read(&memcg->swap)),
1558 K((u64)READ_ONCE(memcg->swap.max)), memcg->swap.failcnt);
1560 pr_info("memory+swap: usage %llukB, limit %llukB, failcnt %lu\n",
1561 K((u64)page_counter_read(&memcg->memsw)),
1562 K((u64)memcg->memsw.max), memcg->memsw.failcnt);
1563 pr_info("kmem: usage %llukB, limit %llukB, failcnt %lu\n",
1564 K((u64)page_counter_read(&memcg->kmem)),
1565 K((u64)memcg->kmem.max), memcg->kmem.failcnt);
1568 pr_info("Memory cgroup stats for ");
1569 pr_cont_cgroup_path(memcg->css.cgroup);
1571 buf = memory_stat_format(memcg);
1579 * Return the memory (and swap, if configured) limit for a memcg.
1581 unsigned long mem_cgroup_get_max(struct mem_cgroup *memcg)
1583 unsigned long max = READ_ONCE(memcg->memory.max);
1585 if (cgroup_subsys_on_dfl(memory_cgrp_subsys)) {
1586 if (mem_cgroup_swappiness(memcg))
1587 max += min(READ_ONCE(memcg->swap.max),
1588 (unsigned long)total_swap_pages);
1590 if (mem_cgroup_swappiness(memcg)) {
1591 /* Calculate swap excess capacity from memsw limit */
1592 unsigned long swap = READ_ONCE(memcg->memsw.max) - max;
1594 max += min(swap, (unsigned long)total_swap_pages);
1600 unsigned long mem_cgroup_size(struct mem_cgroup *memcg)
1602 return page_counter_read(&memcg->memory);
1605 static bool mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask,
1608 struct oom_control oc = {
1612 .gfp_mask = gfp_mask,
1617 if (mutex_lock_killable(&oom_lock))
1620 if (mem_cgroup_margin(memcg) >= (1 << order))
1624 * A few threads which were not waiting at mutex_lock_killable() can
1625 * fail to bail out. Therefore, check again after holding oom_lock.
1627 ret = should_force_charge() || out_of_memory(&oc);
1630 mutex_unlock(&oom_lock);
1634 static int mem_cgroup_soft_reclaim(struct mem_cgroup *root_memcg,
1637 unsigned long *total_scanned)
1639 struct mem_cgroup *victim = NULL;
1642 unsigned long excess;
1643 unsigned long nr_scanned;
1644 struct mem_cgroup_reclaim_cookie reclaim = {
1648 excess = soft_limit_excess(root_memcg);
1651 victim = mem_cgroup_iter(root_memcg, victim, &reclaim);
1656 * If we have not been able to reclaim
1657 * anything, it might because there are
1658 * no reclaimable pages under this hierarchy
1663 * We want to do more targeted reclaim.
1664 * excess >> 2 is not to excessive so as to
1665 * reclaim too much, nor too less that we keep
1666 * coming back to reclaim from this cgroup
1668 if (total >= (excess >> 2) ||
1669 (loop > MEM_CGROUP_MAX_RECLAIM_LOOPS))
1674 total += mem_cgroup_shrink_node(victim, gfp_mask, false,
1675 pgdat, &nr_scanned);
1676 *total_scanned += nr_scanned;
1677 if (!soft_limit_excess(root_memcg))
1680 mem_cgroup_iter_break(root_memcg, victim);
1684 #ifdef CONFIG_LOCKDEP
1685 static struct lockdep_map memcg_oom_lock_dep_map = {
1686 .name = "memcg_oom_lock",
1690 static DEFINE_SPINLOCK(memcg_oom_lock);
1693 * Check OOM-Killer is already running under our hierarchy.
1694 * If someone is running, return false.
1696 static bool mem_cgroup_oom_trylock(struct mem_cgroup *memcg)
1698 struct mem_cgroup *iter, *failed = NULL;
1700 spin_lock(&memcg_oom_lock);
1702 for_each_mem_cgroup_tree(iter, memcg) {
1703 if (iter->oom_lock) {
1705 * this subtree of our hierarchy is already locked
1706 * so we cannot give a lock.
1709 mem_cgroup_iter_break(memcg, iter);
1712 iter->oom_lock = true;
1717 * OK, we failed to lock the whole subtree so we have
1718 * to clean up what we set up to the failing subtree
1720 for_each_mem_cgroup_tree(iter, memcg) {
1721 if (iter == failed) {
1722 mem_cgroup_iter_break(memcg, iter);
1725 iter->oom_lock = false;
1728 mutex_acquire(&memcg_oom_lock_dep_map, 0, 1, _RET_IP_);
1730 spin_unlock(&memcg_oom_lock);
1735 static void mem_cgroup_oom_unlock(struct mem_cgroup *memcg)
1737 struct mem_cgroup *iter;
1739 spin_lock(&memcg_oom_lock);
1740 mutex_release(&memcg_oom_lock_dep_map, _RET_IP_);
1741 for_each_mem_cgroup_tree(iter, memcg)
1742 iter->oom_lock = false;
1743 spin_unlock(&memcg_oom_lock);
1746 static void mem_cgroup_mark_under_oom(struct mem_cgroup *memcg)
1748 struct mem_cgroup *iter;
1750 spin_lock(&memcg_oom_lock);
1751 for_each_mem_cgroup_tree(iter, memcg)
1753 spin_unlock(&memcg_oom_lock);
1756 static void mem_cgroup_unmark_under_oom(struct mem_cgroup *memcg)
1758 struct mem_cgroup *iter;
1761 * Be careful about under_oom underflows because a child memcg
1762 * could have been added after mem_cgroup_mark_under_oom.
1764 spin_lock(&memcg_oom_lock);
1765 for_each_mem_cgroup_tree(iter, memcg)
1766 if (iter->under_oom > 0)
1768 spin_unlock(&memcg_oom_lock);
1771 static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq);
1773 struct oom_wait_info {
1774 struct mem_cgroup *memcg;
1775 wait_queue_entry_t wait;
1778 static int memcg_oom_wake_function(wait_queue_entry_t *wait,
1779 unsigned mode, int sync, void *arg)
1781 struct mem_cgroup *wake_memcg = (struct mem_cgroup *)arg;
1782 struct mem_cgroup *oom_wait_memcg;
1783 struct oom_wait_info *oom_wait_info;
1785 oom_wait_info = container_of(wait, struct oom_wait_info, wait);
1786 oom_wait_memcg = oom_wait_info->memcg;
1788 if (!mem_cgroup_is_descendant(wake_memcg, oom_wait_memcg) &&
1789 !mem_cgroup_is_descendant(oom_wait_memcg, wake_memcg))
1791 return autoremove_wake_function(wait, mode, sync, arg);
1794 static void memcg_oom_recover(struct mem_cgroup *memcg)
1797 * For the following lockless ->under_oom test, the only required
1798 * guarantee is that it must see the state asserted by an OOM when
1799 * this function is called as a result of userland actions
1800 * triggered by the notification of the OOM. This is trivially
1801 * achieved by invoking mem_cgroup_mark_under_oom() before
1802 * triggering notification.
1804 if (memcg && memcg->under_oom)
1805 __wake_up(&memcg_oom_waitq, TASK_NORMAL, 0, memcg);
1815 static enum oom_status mem_cgroup_oom(struct mem_cgroup *memcg, gfp_t mask, int order)
1817 enum oom_status ret;
1820 if (order > PAGE_ALLOC_COSTLY_ORDER)
1823 memcg_memory_event(memcg, MEMCG_OOM);
1826 * We are in the middle of the charge context here, so we
1827 * don't want to block when potentially sitting on a callstack
1828 * that holds all kinds of filesystem and mm locks.
1830 * cgroup1 allows disabling the OOM killer and waiting for outside
1831 * handling until the charge can succeed; remember the context and put
1832 * the task to sleep at the end of the page fault when all locks are
1835 * On the other hand, in-kernel OOM killer allows for an async victim
1836 * memory reclaim (oom_reaper) and that means that we are not solely
1837 * relying on the oom victim to make a forward progress and we can
1838 * invoke the oom killer here.
1840 * Please note that mem_cgroup_out_of_memory might fail to find a
1841 * victim and then we have to bail out from the charge path.
1843 if (memcg->oom_kill_disable) {
1844 if (!current->in_user_fault)
1846 css_get(&memcg->css);
1847 current->memcg_in_oom = memcg;
1848 current->memcg_oom_gfp_mask = mask;
1849 current->memcg_oom_order = order;
1854 mem_cgroup_mark_under_oom(memcg);
1856 locked = mem_cgroup_oom_trylock(memcg);
1859 mem_cgroup_oom_notify(memcg);
1861 mem_cgroup_unmark_under_oom(memcg);
1862 if (mem_cgroup_out_of_memory(memcg, mask, order))
1868 mem_cgroup_oom_unlock(memcg);
1874 * mem_cgroup_oom_synchronize - complete memcg OOM handling
1875 * @handle: actually kill/wait or just clean up the OOM state
1877 * This has to be called at the end of a page fault if the memcg OOM
1878 * handler was enabled.
1880 * Memcg supports userspace OOM handling where failed allocations must
1881 * sleep on a waitqueue until the userspace task resolves the
1882 * situation. Sleeping directly in the charge context with all kinds
1883 * of locks held is not a good idea, instead we remember an OOM state
1884 * in the task and mem_cgroup_oom_synchronize() has to be called at
1885 * the end of the page fault to complete the OOM handling.
1887 * Returns %true if an ongoing memcg OOM situation was detected and
1888 * completed, %false otherwise.
1890 bool mem_cgroup_oom_synchronize(bool handle)
1892 struct mem_cgroup *memcg = current->memcg_in_oom;
1893 struct oom_wait_info owait;
1896 /* OOM is global, do not handle */
1903 owait.memcg = memcg;
1904 owait.wait.flags = 0;
1905 owait.wait.func = memcg_oom_wake_function;
1906 owait.wait.private = current;
1907 INIT_LIST_HEAD(&owait.wait.entry);
1909 prepare_to_wait(&memcg_oom_waitq, &owait.wait, TASK_KILLABLE);
1910 mem_cgroup_mark_under_oom(memcg);
1912 locked = mem_cgroup_oom_trylock(memcg);
1915 mem_cgroup_oom_notify(memcg);
1917 if (locked && !memcg->oom_kill_disable) {
1918 mem_cgroup_unmark_under_oom(memcg);
1919 finish_wait(&memcg_oom_waitq, &owait.wait);
1920 mem_cgroup_out_of_memory(memcg, current->memcg_oom_gfp_mask,
1921 current->memcg_oom_order);
1924 mem_cgroup_unmark_under_oom(memcg);
1925 finish_wait(&memcg_oom_waitq, &owait.wait);
1929 mem_cgroup_oom_unlock(memcg);
1931 * There is no guarantee that an OOM-lock contender
1932 * sees the wakeups triggered by the OOM kill
1933 * uncharges. Wake any sleepers explicitly.
1935 memcg_oom_recover(memcg);
1938 current->memcg_in_oom = NULL;
1939 css_put(&memcg->css);
1944 * mem_cgroup_get_oom_group - get a memory cgroup to clean up after OOM
1945 * @victim: task to be killed by the OOM killer
1946 * @oom_domain: memcg in case of memcg OOM, NULL in case of system-wide OOM
1948 * Returns a pointer to a memory cgroup, which has to be cleaned up
1949 * by killing all belonging OOM-killable tasks.
1951 * Caller has to call mem_cgroup_put() on the returned non-NULL memcg.
1953 struct mem_cgroup *mem_cgroup_get_oom_group(struct task_struct *victim,
1954 struct mem_cgroup *oom_domain)
1956 struct mem_cgroup *oom_group = NULL;
1957 struct mem_cgroup *memcg;
1959 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys))
1963 oom_domain = root_mem_cgroup;
1967 memcg = mem_cgroup_from_task(victim);
1968 if (memcg == root_mem_cgroup)
1972 * If the victim task has been asynchronously moved to a different
1973 * memory cgroup, we might end up killing tasks outside oom_domain.
1974 * In this case it's better to ignore memory.group.oom.
1976 if (unlikely(!mem_cgroup_is_descendant(memcg, oom_domain)))
1980 * Traverse the memory cgroup hierarchy from the victim task's
1981 * cgroup up to the OOMing cgroup (or root) to find the
1982 * highest-level memory cgroup with oom.group set.
1984 for (; memcg; memcg = parent_mem_cgroup(memcg)) {
1985 if (memcg->oom_group)
1988 if (memcg == oom_domain)
1993 css_get(&oom_group->css);
2000 void mem_cgroup_print_oom_group(struct mem_cgroup *memcg)
2002 pr_info("Tasks in ");
2003 pr_cont_cgroup_path(memcg->css.cgroup);
2004 pr_cont(" are going to be killed due to memory.oom.group set\n");
2008 * lock_page_memcg - lock a page and memcg binding
2011 * This function protects unlocked LRU pages from being moved to
2014 * It ensures lifetime of the locked memcg. Caller is responsible
2015 * for the lifetime of the page.
2017 void lock_page_memcg(struct page *page)
2019 struct page *head = compound_head(page); /* rmap on tail pages */
2020 struct mem_cgroup *memcg;
2021 unsigned long flags;
2024 * The RCU lock is held throughout the transaction. The fast
2025 * path can get away without acquiring the memcg->move_lock
2026 * because page moving starts with an RCU grace period.
2030 if (mem_cgroup_disabled())
2033 memcg = page_memcg(head);
2034 if (unlikely(!memcg))
2037 #ifdef CONFIG_PROVE_LOCKING
2038 local_irq_save(flags);
2039 might_lock(&memcg->move_lock);
2040 local_irq_restore(flags);
2043 if (atomic_read(&memcg->moving_account) <= 0)
2046 spin_lock_irqsave(&memcg->move_lock, flags);
2047 if (memcg != page_memcg(head)) {
2048 spin_unlock_irqrestore(&memcg->move_lock, flags);
2053 * When charge migration first begins, we can have multiple
2054 * critical sections holding the fast-path RCU lock and one
2055 * holding the slowpath move_lock. Track the task who has the
2056 * move_lock for unlock_page_memcg().
2058 memcg->move_lock_task = current;
2059 memcg->move_lock_flags = flags;
2061 EXPORT_SYMBOL(lock_page_memcg);
2063 static void __unlock_page_memcg(struct mem_cgroup *memcg)
2065 if (memcg && memcg->move_lock_task == current) {
2066 unsigned long flags = memcg->move_lock_flags;
2068 memcg->move_lock_task = NULL;
2069 memcg->move_lock_flags = 0;
2071 spin_unlock_irqrestore(&memcg->move_lock, flags);
2078 * unlock_page_memcg - unlock a page and memcg binding
2081 void unlock_page_memcg(struct page *page)
2083 struct page *head = compound_head(page);
2085 __unlock_page_memcg(page_memcg(head));
2087 EXPORT_SYMBOL(unlock_page_memcg);
2090 #ifdef CONFIG_MEMCG_KMEM
2091 struct obj_cgroup *cached_objcg;
2092 struct pglist_data *cached_pgdat;
2093 unsigned int nr_bytes;
2094 int nr_slab_reclaimable_b;
2095 int nr_slab_unreclaimable_b;
2101 struct memcg_stock_pcp {
2102 struct mem_cgroup *cached; /* this never be root cgroup */
2103 unsigned int nr_pages;
2104 struct obj_stock task_obj;
2105 struct obj_stock irq_obj;
2107 struct work_struct work;
2108 unsigned long flags;
2109 #define FLUSHING_CACHED_CHARGE 0
2111 static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock);
2112 static DEFINE_MUTEX(percpu_charge_mutex);
2114 #ifdef CONFIG_MEMCG_KMEM
2115 static void drain_obj_stock(struct obj_stock *stock);
2116 static bool obj_stock_flush_required(struct memcg_stock_pcp *stock,
2117 struct mem_cgroup *root_memcg);
2120 static inline void drain_obj_stock(struct obj_stock *stock)
2123 static bool obj_stock_flush_required(struct memcg_stock_pcp *stock,
2124 struct mem_cgroup *root_memcg)
2131 * Most kmem_cache_alloc() calls are from user context. The irq disable/enable
2132 * sequence used in this case to access content from object stock is slow.
2133 * To optimize for user context access, there are now two object stocks for
2134 * task context and interrupt context access respectively.
2136 * The task context object stock can be accessed by disabling preemption only
2137 * which is cheap in non-preempt kernel. The interrupt context object stock
2138 * can only be accessed after disabling interrupt. User context code can
2139 * access interrupt object stock, but not vice versa.
2141 static inline struct obj_stock *get_obj_stock(unsigned long *pflags)
2143 struct memcg_stock_pcp *stock;
2145 if (likely(in_task())) {
2148 stock = this_cpu_ptr(&memcg_stock);
2149 return &stock->task_obj;
2152 local_irq_save(*pflags);
2153 stock = this_cpu_ptr(&memcg_stock);
2154 return &stock->irq_obj;
2157 static inline void put_obj_stock(unsigned long flags)
2159 if (likely(in_task()))
2162 local_irq_restore(flags);
2166 * consume_stock: Try to consume stocked charge on this cpu.
2167 * @memcg: memcg to consume from.
2168 * @nr_pages: how many pages to charge.
2170 * The charges will only happen if @memcg matches the current cpu's memcg
2171 * stock, and at least @nr_pages are available in that stock. Failure to
2172 * service an allocation will refill the stock.
2174 * returns true if successful, false otherwise.
2176 static bool consume_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
2178 struct memcg_stock_pcp *stock;
2179 unsigned long flags;
2182 if (nr_pages > MEMCG_CHARGE_BATCH)
2185 local_irq_save(flags);
2187 stock = this_cpu_ptr(&memcg_stock);
2188 if (memcg == stock->cached && stock->nr_pages >= nr_pages) {
2189 stock->nr_pages -= nr_pages;
2193 local_irq_restore(flags);
2199 * Returns stocks cached in percpu and reset cached information.
2201 static void drain_stock(struct memcg_stock_pcp *stock)
2203 struct mem_cgroup *old = stock->cached;
2208 if (stock->nr_pages) {
2209 page_counter_uncharge(&old->memory, stock->nr_pages);
2210 if (do_memsw_account())
2211 page_counter_uncharge(&old->memsw, stock->nr_pages);
2212 stock->nr_pages = 0;
2216 stock->cached = NULL;
2219 static void drain_local_stock(struct work_struct *dummy)
2221 struct memcg_stock_pcp *stock;
2222 unsigned long flags;
2225 * The only protection from cpu hotplug (memcg_hotplug_cpu_dead) vs.
2226 * drain_stock races is that we always operate on local CPU stock
2227 * here with IRQ disabled
2229 local_irq_save(flags);
2231 stock = this_cpu_ptr(&memcg_stock);
2232 drain_obj_stock(&stock->irq_obj);
2234 drain_obj_stock(&stock->task_obj);
2236 clear_bit(FLUSHING_CACHED_CHARGE, &stock->flags);
2238 local_irq_restore(flags);
2242 * Cache charges(val) to local per_cpu area.
2243 * This will be consumed by consume_stock() function, later.
2245 static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
2247 struct memcg_stock_pcp *stock;
2248 unsigned long flags;
2250 local_irq_save(flags);
2252 stock = this_cpu_ptr(&memcg_stock);
2253 if (stock->cached != memcg) { /* reset if necessary */
2255 css_get(&memcg->css);
2256 stock->cached = memcg;
2258 stock->nr_pages += nr_pages;
2260 if (stock->nr_pages > MEMCG_CHARGE_BATCH)
2263 local_irq_restore(flags);
2267 * Drains all per-CPU charge caches for given root_memcg resp. subtree
2268 * of the hierarchy under it.
2270 static void drain_all_stock(struct mem_cgroup *root_memcg)
2274 /* If someone's already draining, avoid adding running more workers. */
2275 if (!mutex_trylock(&percpu_charge_mutex))
2278 * Notify other cpus that system-wide "drain" is running
2279 * We do not care about races with the cpu hotplug because cpu down
2280 * as well as workers from this path always operate on the local
2281 * per-cpu data. CPU up doesn't touch memcg_stock at all.
2284 for_each_online_cpu(cpu) {
2285 struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
2286 struct mem_cgroup *memcg;
2290 memcg = stock->cached;
2291 if (memcg && stock->nr_pages &&
2292 mem_cgroup_is_descendant(memcg, root_memcg))
2294 else if (obj_stock_flush_required(stock, root_memcg))
2299 !test_and_set_bit(FLUSHING_CACHED_CHARGE, &stock->flags)) {
2301 drain_local_stock(&stock->work);
2303 schedule_work_on(cpu, &stock->work);
2307 mutex_unlock(&percpu_charge_mutex);
2310 static int memcg_hotplug_cpu_dead(unsigned int cpu)
2312 struct memcg_stock_pcp *stock;
2314 stock = &per_cpu(memcg_stock, cpu);
2320 static unsigned long reclaim_high(struct mem_cgroup *memcg,
2321 unsigned int nr_pages,
2324 unsigned long nr_reclaimed = 0;
2327 unsigned long pflags;
2329 if (page_counter_read(&memcg->memory) <=
2330 READ_ONCE(memcg->memory.high))
2333 memcg_memory_event(memcg, MEMCG_HIGH);
2335 psi_memstall_enter(&pflags);
2336 nr_reclaimed += try_to_free_mem_cgroup_pages(memcg, nr_pages,
2338 psi_memstall_leave(&pflags);
2339 } while ((memcg = parent_mem_cgroup(memcg)) &&
2340 !mem_cgroup_is_root(memcg));
2342 return nr_reclaimed;
2345 static void high_work_func(struct work_struct *work)
2347 struct mem_cgroup *memcg;
2349 memcg = container_of(work, struct mem_cgroup, high_work);
2350 reclaim_high(memcg, MEMCG_CHARGE_BATCH, GFP_KERNEL);
2354 * Clamp the maximum sleep time per allocation batch to 2 seconds. This is
2355 * enough to still cause a significant slowdown in most cases, while still
2356 * allowing diagnostics and tracing to proceed without becoming stuck.
2358 #define MEMCG_MAX_HIGH_DELAY_JIFFIES (2UL*HZ)
2361 * When calculating the delay, we use these either side of the exponentiation to
2362 * maintain precision and scale to a reasonable number of jiffies (see the table
2365 * - MEMCG_DELAY_PRECISION_SHIFT: Extra precision bits while translating the
2366 * overage ratio to a delay.
2367 * - MEMCG_DELAY_SCALING_SHIFT: The number of bits to scale down the
2368 * proposed penalty in order to reduce to a reasonable number of jiffies, and
2369 * to produce a reasonable delay curve.
2371 * MEMCG_DELAY_SCALING_SHIFT just happens to be a number that produces a
2372 * reasonable delay curve compared to precision-adjusted overage, not
2373 * penalising heavily at first, but still making sure that growth beyond the
2374 * limit penalises misbehaviour cgroups by slowing them down exponentially. For
2375 * example, with a high of 100 megabytes:
2377 * +-------+------------------------+
2378 * | usage | time to allocate in ms |
2379 * +-------+------------------------+
2401 * +-------+------------------------+
2403 #define MEMCG_DELAY_PRECISION_SHIFT 20
2404 #define MEMCG_DELAY_SCALING_SHIFT 14
2406 static u64 calculate_overage(unsigned long usage, unsigned long high)
2414 * Prevent division by 0 in overage calculation by acting as if
2415 * it was a threshold of 1 page
2417 high = max(high, 1UL);
2419 overage = usage - high;
2420 overage <<= MEMCG_DELAY_PRECISION_SHIFT;
2421 return div64_u64(overage, high);
2424 static u64 mem_find_max_overage(struct mem_cgroup *memcg)
2426 u64 overage, max_overage = 0;
2429 overage = calculate_overage(page_counter_read(&memcg->memory),
2430 READ_ONCE(memcg->memory.high));
2431 max_overage = max(overage, max_overage);
2432 } while ((memcg = parent_mem_cgroup(memcg)) &&
2433 !mem_cgroup_is_root(memcg));
2438 static u64 swap_find_max_overage(struct mem_cgroup *memcg)
2440 u64 overage, max_overage = 0;
2443 overage = calculate_overage(page_counter_read(&memcg->swap),
2444 READ_ONCE(memcg->swap.high));
2446 memcg_memory_event(memcg, MEMCG_SWAP_HIGH);
2447 max_overage = max(overage, max_overage);
2448 } while ((memcg = parent_mem_cgroup(memcg)) &&
2449 !mem_cgroup_is_root(memcg));
2455 * Get the number of jiffies that we should penalise a mischievous cgroup which
2456 * is exceeding its memory.high by checking both it and its ancestors.
2458 static unsigned long calculate_high_delay(struct mem_cgroup *memcg,
2459 unsigned int nr_pages,
2462 unsigned long penalty_jiffies;
2468 * We use overage compared to memory.high to calculate the number of
2469 * jiffies to sleep (penalty_jiffies). Ideally this value should be
2470 * fairly lenient on small overages, and increasingly harsh when the
2471 * memcg in question makes it clear that it has no intention of stopping
2472 * its crazy behaviour, so we exponentially increase the delay based on
2475 penalty_jiffies = max_overage * max_overage * HZ;
2476 penalty_jiffies >>= MEMCG_DELAY_PRECISION_SHIFT;
2477 penalty_jiffies >>= MEMCG_DELAY_SCALING_SHIFT;
2480 * Factor in the task's own contribution to the overage, such that four
2481 * N-sized allocations are throttled approximately the same as one
2482 * 4N-sized allocation.
2484 * MEMCG_CHARGE_BATCH pages is nominal, so work out how much smaller or
2485 * larger the current charge patch is than that.
2487 return penalty_jiffies * nr_pages / MEMCG_CHARGE_BATCH;
2491 * Scheduled by try_charge() to be executed from the userland return path
2492 * and reclaims memory over the high limit.
2494 void mem_cgroup_handle_over_high(void)
2496 unsigned long penalty_jiffies;
2497 unsigned long pflags;
2498 unsigned long nr_reclaimed;
2499 unsigned int nr_pages = current->memcg_nr_pages_over_high;
2500 int nr_retries = MAX_RECLAIM_RETRIES;
2501 struct mem_cgroup *memcg;
2502 bool in_retry = false;
2504 if (likely(!nr_pages))
2507 memcg = get_mem_cgroup_from_mm(current->mm);
2508 current->memcg_nr_pages_over_high = 0;
2512 * The allocating task should reclaim at least the batch size, but for
2513 * subsequent retries we only want to do what's necessary to prevent oom
2514 * or breaching resource isolation.
2516 * This is distinct from memory.max or page allocator behaviour because
2517 * memory.high is currently batched, whereas memory.max and the page
2518 * allocator run every time an allocation is made.
2520 nr_reclaimed = reclaim_high(memcg,
2521 in_retry ? SWAP_CLUSTER_MAX : nr_pages,
2525 * memory.high is breached and reclaim is unable to keep up. Throttle
2526 * allocators proactively to slow down excessive growth.
2528 penalty_jiffies = calculate_high_delay(memcg, nr_pages,
2529 mem_find_max_overage(memcg));
2531 penalty_jiffies += calculate_high_delay(memcg, nr_pages,
2532 swap_find_max_overage(memcg));
2535 * Clamp the max delay per usermode return so as to still keep the
2536 * application moving forwards and also permit diagnostics, albeit
2539 penalty_jiffies = min(penalty_jiffies, MEMCG_MAX_HIGH_DELAY_JIFFIES);
2542 * Don't sleep if the amount of jiffies this memcg owes us is so low
2543 * that it's not even worth doing, in an attempt to be nice to those who
2544 * go only a small amount over their memory.high value and maybe haven't
2545 * been aggressively reclaimed enough yet.
2547 if (penalty_jiffies <= HZ / 100)
2551 * If reclaim is making forward progress but we're still over
2552 * memory.high, we want to encourage that rather than doing allocator
2555 if (nr_reclaimed || nr_retries--) {
2561 * If we exit early, we're guaranteed to die (since
2562 * schedule_timeout_killable sets TASK_KILLABLE). This means we don't
2563 * need to account for any ill-begotten jiffies to pay them off later.
2565 psi_memstall_enter(&pflags);
2566 schedule_timeout_killable(penalty_jiffies);
2567 psi_memstall_leave(&pflags);
2570 css_put(&memcg->css);
2573 static int try_charge_memcg(struct mem_cgroup *memcg, gfp_t gfp_mask,
2574 unsigned int nr_pages)
2576 unsigned int batch = max(MEMCG_CHARGE_BATCH, nr_pages);
2577 int nr_retries = MAX_RECLAIM_RETRIES;
2578 struct mem_cgroup *mem_over_limit;
2579 struct page_counter *counter;
2580 enum oom_status oom_status;
2581 unsigned long nr_reclaimed;
2582 bool may_swap = true;
2583 bool drained = false;
2584 unsigned long pflags;
2587 if (consume_stock(memcg, nr_pages))
2590 if (!do_memsw_account() ||
2591 page_counter_try_charge(&memcg->memsw, batch, &counter)) {
2592 if (page_counter_try_charge(&memcg->memory, batch, &counter))
2594 if (do_memsw_account())
2595 page_counter_uncharge(&memcg->memsw, batch);
2596 mem_over_limit = mem_cgroup_from_counter(counter, memory);
2598 mem_over_limit = mem_cgroup_from_counter(counter, memsw);
2602 if (batch > nr_pages) {
2608 * Memcg doesn't have a dedicated reserve for atomic
2609 * allocations. But like the global atomic pool, we need to
2610 * put the burden of reclaim on regular allocation requests
2611 * and let these go through as privileged allocations.
2613 if (gfp_mask & __GFP_ATOMIC)
2617 * Unlike in global OOM situations, memcg is not in a physical
2618 * memory shortage. Allow dying and OOM-killed tasks to
2619 * bypass the last charges so that they can exit quickly and
2620 * free their memory.
2622 if (unlikely(should_force_charge()))
2626 * Prevent unbounded recursion when reclaim operations need to
2627 * allocate memory. This might exceed the limits temporarily,
2628 * but we prefer facilitating memory reclaim and getting back
2629 * under the limit over triggering OOM kills in these cases.
2631 if (unlikely(current->flags & PF_MEMALLOC))
2634 if (unlikely(task_in_memcg_oom(current)))
2637 if (!gfpflags_allow_blocking(gfp_mask))
2640 memcg_memory_event(mem_over_limit, MEMCG_MAX);
2642 psi_memstall_enter(&pflags);
2643 nr_reclaimed = try_to_free_mem_cgroup_pages(mem_over_limit, nr_pages,
2644 gfp_mask, may_swap);
2645 psi_memstall_leave(&pflags);
2647 if (mem_cgroup_margin(mem_over_limit) >= nr_pages)
2651 drain_all_stock(mem_over_limit);
2656 if (gfp_mask & __GFP_NORETRY)
2659 * Even though the limit is exceeded at this point, reclaim
2660 * may have been able to free some pages. Retry the charge
2661 * before killing the task.
2663 * Only for regular pages, though: huge pages are rather
2664 * unlikely to succeed so close to the limit, and we fall back
2665 * to regular pages anyway in case of failure.
2667 if (nr_reclaimed && nr_pages <= (1 << PAGE_ALLOC_COSTLY_ORDER))
2670 * At task move, charge accounts can be doubly counted. So, it's
2671 * better to wait until the end of task_move if something is going on.
2673 if (mem_cgroup_wait_acct_move(mem_over_limit))
2679 if (gfp_mask & __GFP_RETRY_MAYFAIL)
2682 if (fatal_signal_pending(current))
2686 * keep retrying as long as the memcg oom killer is able to make
2687 * a forward progress or bypass the charge if the oom killer
2688 * couldn't make any progress.
2690 oom_status = mem_cgroup_oom(mem_over_limit, gfp_mask,
2691 get_order(nr_pages * PAGE_SIZE));
2692 switch (oom_status) {
2694 nr_retries = MAX_RECLAIM_RETRIES;
2702 if (!(gfp_mask & __GFP_NOFAIL))
2706 * The allocation either can't fail or will lead to more memory
2707 * being freed very soon. Allow memory usage go over the limit
2708 * temporarily by force charging it.
2710 page_counter_charge(&memcg->memory, nr_pages);
2711 if (do_memsw_account())
2712 page_counter_charge(&memcg->memsw, nr_pages);
2717 if (batch > nr_pages)
2718 refill_stock(memcg, batch - nr_pages);
2721 * If the hierarchy is above the normal consumption range, schedule
2722 * reclaim on returning to userland. We can perform reclaim here
2723 * if __GFP_RECLAIM but let's always punt for simplicity and so that
2724 * GFP_KERNEL can consistently be used during reclaim. @memcg is
2725 * not recorded as it most likely matches current's and won't
2726 * change in the meantime. As high limit is checked again before
2727 * reclaim, the cost of mismatch is negligible.
2730 bool mem_high, swap_high;
2732 mem_high = page_counter_read(&memcg->memory) >
2733 READ_ONCE(memcg->memory.high);
2734 swap_high = page_counter_read(&memcg->swap) >
2735 READ_ONCE(memcg->swap.high);
2737 /* Don't bother a random interrupted task */
2738 if (in_interrupt()) {
2740 schedule_work(&memcg->high_work);
2746 if (mem_high || swap_high) {
2748 * The allocating tasks in this cgroup will need to do
2749 * reclaim or be throttled to prevent further growth
2750 * of the memory or swap footprints.
2752 * Target some best-effort fairness between the tasks,
2753 * and distribute reclaim work and delay penalties
2754 * based on how much each task is actually allocating.
2756 current->memcg_nr_pages_over_high += batch;
2757 set_notify_resume(current);
2760 } while ((memcg = parent_mem_cgroup(memcg)));
2765 static inline int try_charge(struct mem_cgroup *memcg, gfp_t gfp_mask,
2766 unsigned int nr_pages)
2768 if (mem_cgroup_is_root(memcg))
2771 return try_charge_memcg(memcg, gfp_mask, nr_pages);
2774 #if defined(CONFIG_MEMCG_KMEM) || defined(CONFIG_MMU)
2775 static void cancel_charge(struct mem_cgroup *memcg, unsigned int nr_pages)
2777 if (mem_cgroup_is_root(memcg))
2780 page_counter_uncharge(&memcg->memory, nr_pages);
2781 if (do_memsw_account())
2782 page_counter_uncharge(&memcg->memsw, nr_pages);
2786 static void commit_charge(struct page *page, struct mem_cgroup *memcg)
2788 VM_BUG_ON_PAGE(page_memcg(page), page);
2790 * Any of the following ensures page's memcg stability:
2794 * - lock_page_memcg()
2795 * - exclusive reference
2797 page->memcg_data = (unsigned long)memcg;
2800 static struct mem_cgroup *get_mem_cgroup_from_objcg(struct obj_cgroup *objcg)
2802 struct mem_cgroup *memcg;
2806 memcg = obj_cgroup_memcg(objcg);
2807 if (unlikely(!css_tryget(&memcg->css)))
2814 #ifdef CONFIG_MEMCG_KMEM
2816 * The allocated objcg pointers array is not accounted directly.
2817 * Moreover, it should not come from DMA buffer and is not readily
2818 * reclaimable. So those GFP bits should be masked off.
2820 #define OBJCGS_CLEAR_MASK (__GFP_DMA | __GFP_RECLAIMABLE | __GFP_ACCOUNT)
2822 int memcg_alloc_page_obj_cgroups(struct page *page, struct kmem_cache *s,
2823 gfp_t gfp, bool new_page)
2825 unsigned int objects = objs_per_slab_page(s, page);
2826 unsigned long memcg_data;
2829 gfp &= ~OBJCGS_CLEAR_MASK;
2830 vec = kcalloc_node(objects, sizeof(struct obj_cgroup *), gfp,
2835 memcg_data = (unsigned long) vec | MEMCG_DATA_OBJCGS;
2838 * If the slab page is brand new and nobody can yet access
2839 * it's memcg_data, no synchronization is required and
2840 * memcg_data can be simply assigned.
2842 page->memcg_data = memcg_data;
2843 } else if (cmpxchg(&page->memcg_data, 0, memcg_data)) {
2845 * If the slab page is already in use, somebody can allocate
2846 * and assign obj_cgroups in parallel. In this case the existing
2847 * objcg vector should be reused.
2853 kmemleak_not_leak(vec);
2858 * Returns a pointer to the memory cgroup to which the kernel object is charged.
2860 * A passed kernel object can be a slab object or a generic kernel page, so
2861 * different mechanisms for getting the memory cgroup pointer should be used.
2862 * In certain cases (e.g. kernel stacks or large kmallocs with SLUB) the caller
2863 * can not know for sure how the kernel object is implemented.
2864 * mem_cgroup_from_obj() can be safely used in such cases.
2866 * The caller must ensure the memcg lifetime, e.g. by taking rcu_read_lock(),
2867 * cgroup_mutex, etc.
2869 struct mem_cgroup *mem_cgroup_from_obj(void *p)
2873 if (mem_cgroup_disabled())
2876 page = virt_to_head_page(p);
2879 * Slab objects are accounted individually, not per-page.
2880 * Memcg membership data for each individual object is saved in
2881 * the page->obj_cgroups.
2883 if (page_objcgs_check(page)) {
2884 struct obj_cgroup *objcg;
2887 off = obj_to_index(page->slab_cache, page, p);
2888 objcg = page_objcgs(page)[off];
2890 return obj_cgroup_memcg(objcg);
2896 * page_memcg_check() is used here, because page_has_obj_cgroups()
2897 * check above could fail because the object cgroups vector wasn't set
2898 * at that moment, but it can be set concurrently.
2899 * page_memcg_check(page) will guarantee that a proper memory
2900 * cgroup pointer or NULL will be returned.
2902 return page_memcg_check(page);
2905 __always_inline struct obj_cgroup *get_obj_cgroup_from_current(void)
2907 struct obj_cgroup *objcg = NULL;
2908 struct mem_cgroup *memcg;
2910 if (memcg_kmem_bypass())
2914 if (unlikely(active_memcg()))
2915 memcg = active_memcg();
2917 memcg = mem_cgroup_from_task(current);
2919 for (; memcg != root_mem_cgroup; memcg = parent_mem_cgroup(memcg)) {
2920 objcg = rcu_dereference(memcg->objcg);
2921 if (objcg && obj_cgroup_tryget(objcg))
2930 static int memcg_alloc_cache_id(void)
2935 id = ida_simple_get(&memcg_cache_ida,
2936 0, MEMCG_CACHES_MAX_SIZE, GFP_KERNEL);
2940 if (id < memcg_nr_cache_ids)
2944 * There's no space for the new id in memcg_caches arrays,
2945 * so we have to grow them.
2947 down_write(&memcg_cache_ids_sem);
2949 size = 2 * (id + 1);
2950 if (size < MEMCG_CACHES_MIN_SIZE)
2951 size = MEMCG_CACHES_MIN_SIZE;
2952 else if (size > MEMCG_CACHES_MAX_SIZE)
2953 size = MEMCG_CACHES_MAX_SIZE;
2955 err = memcg_update_all_list_lrus(size);
2957 memcg_nr_cache_ids = size;
2959 up_write(&memcg_cache_ids_sem);
2962 ida_simple_remove(&memcg_cache_ida, id);
2968 static void memcg_free_cache_id(int id)
2970 ida_simple_remove(&memcg_cache_ida, id);
2974 * obj_cgroup_uncharge_pages: uncharge a number of kernel pages from a objcg
2975 * @objcg: object cgroup to uncharge
2976 * @nr_pages: number of pages to uncharge
2978 static void obj_cgroup_uncharge_pages(struct obj_cgroup *objcg,
2979 unsigned int nr_pages)
2981 struct mem_cgroup *memcg;
2983 memcg = get_mem_cgroup_from_objcg(objcg);
2985 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys))
2986 page_counter_uncharge(&memcg->kmem, nr_pages);
2987 refill_stock(memcg, nr_pages);
2989 css_put(&memcg->css);
2993 * obj_cgroup_charge_pages: charge a number of kernel pages to a objcg
2994 * @objcg: object cgroup to charge
2995 * @gfp: reclaim mode
2996 * @nr_pages: number of pages to charge
2998 * Returns 0 on success, an error code on failure.
3000 static int obj_cgroup_charge_pages(struct obj_cgroup *objcg, gfp_t gfp,
3001 unsigned int nr_pages)
3003 struct page_counter *counter;
3004 struct mem_cgroup *memcg;
3007 memcg = get_mem_cgroup_from_objcg(objcg);
3009 ret = try_charge_memcg(memcg, gfp, nr_pages);
3013 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) &&
3014 !page_counter_try_charge(&memcg->kmem, nr_pages, &counter)) {
3017 * Enforce __GFP_NOFAIL allocation because callers are not
3018 * prepared to see failures and likely do not have any failure
3021 if (gfp & __GFP_NOFAIL) {
3022 page_counter_charge(&memcg->kmem, nr_pages);
3025 cancel_charge(memcg, nr_pages);
3029 css_put(&memcg->css);
3035 * __memcg_kmem_charge_page: charge a kmem page to the current memory cgroup
3036 * @page: page to charge
3037 * @gfp: reclaim mode
3038 * @order: allocation order
3040 * Returns 0 on success, an error code on failure.
3042 int __memcg_kmem_charge_page(struct page *page, gfp_t gfp, int order)
3044 struct obj_cgroup *objcg;
3047 objcg = get_obj_cgroup_from_current();
3049 ret = obj_cgroup_charge_pages(objcg, gfp, 1 << order);
3051 page->memcg_data = (unsigned long)objcg |
3055 obj_cgroup_put(objcg);
3061 * __memcg_kmem_uncharge_page: uncharge a kmem page
3062 * @page: page to uncharge
3063 * @order: allocation order
3065 void __memcg_kmem_uncharge_page(struct page *page, int order)
3067 struct obj_cgroup *objcg;
3068 unsigned int nr_pages = 1 << order;
3070 if (!PageMemcgKmem(page))
3073 objcg = __page_objcg(page);
3074 obj_cgroup_uncharge_pages(objcg, nr_pages);
3075 page->memcg_data = 0;
3076 obj_cgroup_put(objcg);
3079 void mod_objcg_state(struct obj_cgroup *objcg, struct pglist_data *pgdat,
3080 enum node_stat_item idx, int nr)
3082 unsigned long flags;
3083 struct obj_stock *stock = get_obj_stock(&flags);
3087 * Save vmstat data in stock and skip vmstat array update unless
3088 * accumulating over a page of vmstat data or when pgdat or idx
3091 if (stock->cached_objcg != objcg) {
3092 drain_obj_stock(stock);
3093 obj_cgroup_get(objcg);
3094 stock->nr_bytes = atomic_read(&objcg->nr_charged_bytes)
3095 ? atomic_xchg(&objcg->nr_charged_bytes, 0) : 0;
3096 stock->cached_objcg = objcg;
3097 stock->cached_pgdat = pgdat;
3098 } else if (stock->cached_pgdat != pgdat) {
3099 /* Flush the existing cached vmstat data */
3100 struct pglist_data *oldpg = stock->cached_pgdat;
3102 if (stock->nr_slab_reclaimable_b) {
3103 mod_objcg_mlstate(objcg, oldpg, NR_SLAB_RECLAIMABLE_B,
3104 stock->nr_slab_reclaimable_b);
3105 stock->nr_slab_reclaimable_b = 0;
3107 if (stock->nr_slab_unreclaimable_b) {
3108 mod_objcg_mlstate(objcg, oldpg, NR_SLAB_UNRECLAIMABLE_B,
3109 stock->nr_slab_unreclaimable_b);
3110 stock->nr_slab_unreclaimable_b = 0;
3112 stock->cached_pgdat = pgdat;
3115 bytes = (idx == NR_SLAB_RECLAIMABLE_B) ? &stock->nr_slab_reclaimable_b
3116 : &stock->nr_slab_unreclaimable_b;
3118 * Even for large object >= PAGE_SIZE, the vmstat data will still be
3119 * cached locally at least once before pushing it out.
3126 if (abs(*bytes) > PAGE_SIZE) {
3134 mod_objcg_mlstate(objcg, pgdat, idx, nr);
3136 put_obj_stock(flags);
3139 static bool consume_obj_stock(struct obj_cgroup *objcg, unsigned int nr_bytes)
3141 unsigned long flags;
3142 struct obj_stock *stock = get_obj_stock(&flags);
3145 if (objcg == stock->cached_objcg && stock->nr_bytes >= nr_bytes) {
3146 stock->nr_bytes -= nr_bytes;
3150 put_obj_stock(flags);
3155 static void drain_obj_stock(struct obj_stock *stock)
3157 struct obj_cgroup *old = stock->cached_objcg;
3162 if (stock->nr_bytes) {
3163 unsigned int nr_pages = stock->nr_bytes >> PAGE_SHIFT;
3164 unsigned int nr_bytes = stock->nr_bytes & (PAGE_SIZE - 1);
3167 obj_cgroup_uncharge_pages(old, nr_pages);
3170 * The leftover is flushed to the centralized per-memcg value.
3171 * On the next attempt to refill obj stock it will be moved
3172 * to a per-cpu stock (probably, on an other CPU), see
3173 * refill_obj_stock().
3175 * How often it's flushed is a trade-off between the memory
3176 * limit enforcement accuracy and potential CPU contention,
3177 * so it might be changed in the future.
3179 atomic_add(nr_bytes, &old->nr_charged_bytes);
3180 stock->nr_bytes = 0;
3184 * Flush the vmstat data in current stock
3186 if (stock->nr_slab_reclaimable_b || stock->nr_slab_unreclaimable_b) {
3187 if (stock->nr_slab_reclaimable_b) {
3188 mod_objcg_mlstate(old, stock->cached_pgdat,
3189 NR_SLAB_RECLAIMABLE_B,
3190 stock->nr_slab_reclaimable_b);
3191 stock->nr_slab_reclaimable_b = 0;
3193 if (stock->nr_slab_unreclaimable_b) {
3194 mod_objcg_mlstate(old, stock->cached_pgdat,
3195 NR_SLAB_UNRECLAIMABLE_B,
3196 stock->nr_slab_unreclaimable_b);
3197 stock->nr_slab_unreclaimable_b = 0;
3199 stock->cached_pgdat = NULL;
3202 obj_cgroup_put(old);
3203 stock->cached_objcg = NULL;
3206 static bool obj_stock_flush_required(struct memcg_stock_pcp *stock,
3207 struct mem_cgroup *root_memcg)
3209 struct mem_cgroup *memcg;
3211 if (in_task() && stock->task_obj.cached_objcg) {
3212 memcg = obj_cgroup_memcg(stock->task_obj.cached_objcg);
3213 if (memcg && mem_cgroup_is_descendant(memcg, root_memcg))
3216 if (stock->irq_obj.cached_objcg) {
3217 memcg = obj_cgroup_memcg(stock->irq_obj.cached_objcg);
3218 if (memcg && mem_cgroup_is_descendant(memcg, root_memcg))
3225 static void refill_obj_stock(struct obj_cgroup *objcg, unsigned int nr_bytes,
3226 bool allow_uncharge)
3228 unsigned long flags;
3229 struct obj_stock *stock = get_obj_stock(&flags);
3230 unsigned int nr_pages = 0;
3232 if (stock->cached_objcg != objcg) { /* reset if necessary */
3233 drain_obj_stock(stock);
3234 obj_cgroup_get(objcg);
3235 stock->cached_objcg = objcg;
3236 stock->nr_bytes = atomic_read(&objcg->nr_charged_bytes)
3237 ? atomic_xchg(&objcg->nr_charged_bytes, 0) : 0;
3238 allow_uncharge = true; /* Allow uncharge when objcg changes */
3240 stock->nr_bytes += nr_bytes;
3242 if (allow_uncharge && (stock->nr_bytes > PAGE_SIZE)) {
3243 nr_pages = stock->nr_bytes >> PAGE_SHIFT;
3244 stock->nr_bytes &= (PAGE_SIZE - 1);
3247 put_obj_stock(flags);
3250 obj_cgroup_uncharge_pages(objcg, nr_pages);
3253 int obj_cgroup_charge(struct obj_cgroup *objcg, gfp_t gfp, size_t size)
3255 unsigned int nr_pages, nr_bytes;
3258 if (consume_obj_stock(objcg, size))
3262 * In theory, objcg->nr_charged_bytes can have enough
3263 * pre-charged bytes to satisfy the allocation. However,
3264 * flushing objcg->nr_charged_bytes requires two atomic
3265 * operations, and objcg->nr_charged_bytes can't be big.
3266 * The shared objcg->nr_charged_bytes can also become a
3267 * performance bottleneck if all tasks of the same memcg are
3268 * trying to update it. So it's better to ignore it and try
3269 * grab some new pages. The stock's nr_bytes will be flushed to
3270 * objcg->nr_charged_bytes later on when objcg changes.
3272 * The stock's nr_bytes may contain enough pre-charged bytes
3273 * to allow one less page from being charged, but we can't rely
3274 * on the pre-charged bytes not being changed outside of
3275 * consume_obj_stock() or refill_obj_stock(). So ignore those
3276 * pre-charged bytes as well when charging pages. To avoid a
3277 * page uncharge right after a page charge, we set the
3278 * allow_uncharge flag to false when calling refill_obj_stock()
3279 * to temporarily allow the pre-charged bytes to exceed the page
3280 * size limit. The maximum reachable value of the pre-charged
3281 * bytes is (sizeof(object) + PAGE_SIZE - 2) if there is no data
3284 nr_pages = size >> PAGE_SHIFT;
3285 nr_bytes = size & (PAGE_SIZE - 1);
3290 ret = obj_cgroup_charge_pages(objcg, gfp, nr_pages);
3291 if (!ret && nr_bytes)
3292 refill_obj_stock(objcg, PAGE_SIZE - nr_bytes, false);
3297 void obj_cgroup_uncharge(struct obj_cgroup *objcg, size_t size)
3299 refill_obj_stock(objcg, size, true);
3302 #endif /* CONFIG_MEMCG_KMEM */
3305 * Because page_memcg(head) is not set on tails, set it now.
3307 void split_page_memcg(struct page *head, unsigned int nr)
3309 struct mem_cgroup *memcg = page_memcg(head);
3312 if (mem_cgroup_disabled() || !memcg)
3315 for (i = 1; i < nr; i++)
3316 head[i].memcg_data = head->memcg_data;
3318 if (PageMemcgKmem(head))
3319 obj_cgroup_get_many(__page_objcg(head), nr - 1);
3321 css_get_many(&memcg->css, nr - 1);
3324 #ifdef CONFIG_MEMCG_SWAP
3326 * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record.
3327 * @entry: swap entry to be moved
3328 * @from: mem_cgroup which the entry is moved from
3329 * @to: mem_cgroup which the entry is moved to
3331 * It succeeds only when the swap_cgroup's record for this entry is the same
3332 * as the mem_cgroup's id of @from.
3334 * Returns 0 on success, -EINVAL on failure.
3336 * The caller must have charged to @to, IOW, called page_counter_charge() about
3337 * both res and memsw, and called css_get().
3339 static int mem_cgroup_move_swap_account(swp_entry_t entry,
3340 struct mem_cgroup *from, struct mem_cgroup *to)
3342 unsigned short old_id, new_id;
3344 old_id = mem_cgroup_id(from);
3345 new_id = mem_cgroup_id(to);
3347 if (swap_cgroup_cmpxchg(entry, old_id, new_id) == old_id) {
3348 mod_memcg_state(from, MEMCG_SWAP, -1);
3349 mod_memcg_state(to, MEMCG_SWAP, 1);
3355 static inline int mem_cgroup_move_swap_account(swp_entry_t entry,
3356 struct mem_cgroup *from, struct mem_cgroup *to)
3362 static DEFINE_MUTEX(memcg_max_mutex);
3364 static int mem_cgroup_resize_max(struct mem_cgroup *memcg,
3365 unsigned long max, bool memsw)
3367 bool enlarge = false;
3368 bool drained = false;
3370 bool limits_invariant;
3371 struct page_counter *counter = memsw ? &memcg->memsw : &memcg->memory;
3374 if (signal_pending(current)) {
3379 mutex_lock(&memcg_max_mutex);
3381 * Make sure that the new limit (memsw or memory limit) doesn't
3382 * break our basic invariant rule memory.max <= memsw.max.
3384 limits_invariant = memsw ? max >= READ_ONCE(memcg->memory.max) :
3385 max <= memcg->memsw.max;
3386 if (!limits_invariant) {
3387 mutex_unlock(&memcg_max_mutex);
3391 if (max > counter->max)
3393 ret = page_counter_set_max(counter, max);
3394 mutex_unlock(&memcg_max_mutex);
3400 drain_all_stock(memcg);
3405 if (!try_to_free_mem_cgroup_pages(memcg, 1,
3406 GFP_KERNEL, !memsw)) {
3412 if (!ret && enlarge)
3413 memcg_oom_recover(memcg);
3418 unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order,
3420 unsigned long *total_scanned)
3422 unsigned long nr_reclaimed = 0;
3423 struct mem_cgroup_per_node *mz, *next_mz = NULL;
3424 unsigned long reclaimed;
3426 struct mem_cgroup_tree_per_node *mctz;
3427 unsigned long excess;
3428 unsigned long nr_scanned;
3433 mctz = soft_limit_tree_node(pgdat->node_id);
3436 * Do not even bother to check the largest node if the root
3437 * is empty. Do it lockless to prevent lock bouncing. Races
3438 * are acceptable as soft limit is best effort anyway.
3440 if (!mctz || RB_EMPTY_ROOT(&mctz->rb_root))
3444 * This loop can run a while, specially if mem_cgroup's continuously
3445 * keep exceeding their soft limit and putting the system under
3452 mz = mem_cgroup_largest_soft_limit_node(mctz);
3457 reclaimed = mem_cgroup_soft_reclaim(mz->memcg, pgdat,
3458 gfp_mask, &nr_scanned);
3459 nr_reclaimed += reclaimed;
3460 *total_scanned += nr_scanned;
3461 spin_lock_irq(&mctz->lock);
3462 __mem_cgroup_remove_exceeded(mz, mctz);
3465 * If we failed to reclaim anything from this memory cgroup
3466 * it is time to move on to the next cgroup
3470 next_mz = __mem_cgroup_largest_soft_limit_node(mctz);
3472 excess = soft_limit_excess(mz->memcg);
3474 * One school of thought says that we should not add
3475 * back the node to the tree if reclaim returns 0.
3476 * But our reclaim could return 0, simply because due
3477 * to priority we are exposing a smaller subset of
3478 * memory to reclaim from. Consider this as a longer
3481 /* If excess == 0, no tree ops */
3482 __mem_cgroup_insert_exceeded(mz, mctz, excess);
3483 spin_unlock_irq(&mctz->lock);
3484 css_put(&mz->memcg->css);
3487 * Could not reclaim anything and there are no more
3488 * mem cgroups to try or we seem to be looping without
3489 * reclaiming anything.
3491 if (!nr_reclaimed &&
3493 loop > MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS))
3495 } while (!nr_reclaimed);
3497 css_put(&next_mz->memcg->css);
3498 return nr_reclaimed;
3502 * Reclaims as many pages from the given memcg as possible.
3504 * Caller is responsible for holding css reference for memcg.
3506 static int mem_cgroup_force_empty(struct mem_cgroup *memcg)
3508 int nr_retries = MAX_RECLAIM_RETRIES;
3510 /* we call try-to-free pages for make this cgroup empty */
3511 lru_add_drain_all();
3513 drain_all_stock(memcg);
3515 /* try to free all pages in this cgroup */
3516 while (nr_retries && page_counter_read(&memcg->memory)) {
3519 if (signal_pending(current))
3522 progress = try_to_free_mem_cgroup_pages(memcg, 1,
3526 /* maybe some writeback is necessary */
3527 congestion_wait(BLK_RW_ASYNC, HZ/10);
3535 static ssize_t mem_cgroup_force_empty_write(struct kernfs_open_file *of,
3536 char *buf, size_t nbytes,
3539 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
3541 if (mem_cgroup_is_root(memcg))
3543 return mem_cgroup_force_empty(memcg) ?: nbytes;
3546 static u64 mem_cgroup_hierarchy_read(struct cgroup_subsys_state *css,
3552 static int mem_cgroup_hierarchy_write(struct cgroup_subsys_state *css,
3553 struct cftype *cft, u64 val)
3558 pr_warn_once("Non-hierarchical mode is deprecated. "
3559 "Please report your usecase to linux-mm@kvack.org if you "
3560 "depend on this functionality.\n");
3565 static unsigned long mem_cgroup_usage(struct mem_cgroup *memcg, bool swap)
3569 if (mem_cgroup_is_root(memcg)) {
3570 mem_cgroup_flush_stats();
3571 val = memcg_page_state(memcg, NR_FILE_PAGES) +
3572 memcg_page_state(memcg, NR_ANON_MAPPED);
3574 val += memcg_page_state(memcg, MEMCG_SWAP);
3577 val = page_counter_read(&memcg->memory);
3579 val = page_counter_read(&memcg->memsw);
3592 static u64 mem_cgroup_read_u64(struct cgroup_subsys_state *css,
3595 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
3596 struct page_counter *counter;
3598 switch (MEMFILE_TYPE(cft->private)) {
3600 counter = &memcg->memory;
3603 counter = &memcg->memsw;
3606 counter = &memcg->kmem;
3609 counter = &memcg->tcpmem;
3615 switch (MEMFILE_ATTR(cft->private)) {
3617 if (counter == &memcg->memory)
3618 return (u64)mem_cgroup_usage(memcg, false) * PAGE_SIZE;
3619 if (counter == &memcg->memsw)
3620 return (u64)mem_cgroup_usage(memcg, true) * PAGE_SIZE;
3621 return (u64)page_counter_read(counter) * PAGE_SIZE;
3623 return (u64)counter->max * PAGE_SIZE;
3625 return (u64)counter->watermark * PAGE_SIZE;
3627 return counter->failcnt;
3628 case RES_SOFT_LIMIT:
3629 return (u64)memcg->soft_limit * PAGE_SIZE;
3635 #ifdef CONFIG_MEMCG_KMEM
3636 static int memcg_online_kmem(struct mem_cgroup *memcg)
3638 struct obj_cgroup *objcg;
3641 if (cgroup_memory_nokmem)
3644 BUG_ON(memcg->kmemcg_id >= 0);
3645 BUG_ON(memcg->kmem_state);
3647 memcg_id = memcg_alloc_cache_id();
3651 objcg = obj_cgroup_alloc();
3653 memcg_free_cache_id(memcg_id);
3656 objcg->memcg = memcg;
3657 rcu_assign_pointer(memcg->objcg, objcg);
3659 static_branch_enable(&memcg_kmem_enabled_key);
3661 memcg->kmemcg_id = memcg_id;
3662 memcg->kmem_state = KMEM_ONLINE;
3667 static void memcg_offline_kmem(struct mem_cgroup *memcg)
3669 struct cgroup_subsys_state *css;
3670 struct mem_cgroup *parent, *child;
3673 if (memcg->kmem_state != KMEM_ONLINE)
3676 memcg->kmem_state = KMEM_ALLOCATED;
3678 parent = parent_mem_cgroup(memcg);
3680 parent = root_mem_cgroup;
3682 memcg_reparent_objcgs(memcg, parent);
3684 kmemcg_id = memcg->kmemcg_id;
3685 BUG_ON(kmemcg_id < 0);
3688 * Change kmemcg_id of this cgroup and all its descendants to the
3689 * parent's id, and then move all entries from this cgroup's list_lrus
3690 * to ones of the parent. After we have finished, all list_lrus
3691 * corresponding to this cgroup are guaranteed to remain empty. The
3692 * ordering is imposed by list_lru_node->lock taken by
3693 * memcg_drain_all_list_lrus().
3695 rcu_read_lock(); /* can be called from css_free w/o cgroup_mutex */
3696 css_for_each_descendant_pre(css, &memcg->css) {
3697 child = mem_cgroup_from_css(css);
3698 BUG_ON(child->kmemcg_id != kmemcg_id);
3699 child->kmemcg_id = parent->kmemcg_id;
3703 memcg_drain_all_list_lrus(kmemcg_id, parent);
3705 memcg_free_cache_id(kmemcg_id);
3708 static int memcg_online_kmem(struct mem_cgroup *memcg)
3712 static void memcg_offline_kmem(struct mem_cgroup *memcg)
3715 #endif /* CONFIG_MEMCG_KMEM */
3717 static int memcg_update_kmem_max(struct mem_cgroup *memcg,
3722 mutex_lock(&memcg_max_mutex);
3723 ret = page_counter_set_max(&memcg->kmem, max);
3724 mutex_unlock(&memcg_max_mutex);
3728 static int memcg_update_tcp_max(struct mem_cgroup *memcg, unsigned long max)
3732 mutex_lock(&memcg_max_mutex);
3734 ret = page_counter_set_max(&memcg->tcpmem, max);
3738 if (!memcg->tcpmem_active) {
3740 * The active flag needs to be written after the static_key
3741 * update. This is what guarantees that the socket activation
3742 * function is the last one to run. See mem_cgroup_sk_alloc()
3743 * for details, and note that we don't mark any socket as
3744 * belonging to this memcg until that flag is up.
3746 * We need to do this, because static_keys will span multiple
3747 * sites, but we can't control their order. If we mark a socket
3748 * as accounted, but the accounting functions are not patched in
3749 * yet, we'll lose accounting.
3751 * We never race with the readers in mem_cgroup_sk_alloc(),
3752 * because when this value change, the code to process it is not
3755 static_branch_inc(&memcg_sockets_enabled_key);
3756 memcg->tcpmem_active = true;
3759 mutex_unlock(&memcg_max_mutex);
3764 * The user of this function is...
3767 static ssize_t mem_cgroup_write(struct kernfs_open_file *of,
3768 char *buf, size_t nbytes, loff_t off)
3770 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
3771 unsigned long nr_pages;
3774 buf = strstrip(buf);
3775 ret = page_counter_memparse(buf, "-1", &nr_pages);
3779 switch (MEMFILE_ATTR(of_cft(of)->private)) {
3781 if (mem_cgroup_is_root(memcg)) { /* Can't set limit on root */
3785 switch (MEMFILE_TYPE(of_cft(of)->private)) {
3787 ret = mem_cgroup_resize_max(memcg, nr_pages, false);
3790 ret = mem_cgroup_resize_max(memcg, nr_pages, true);
3793 pr_warn_once("kmem.limit_in_bytes is deprecated and will be removed. "
3794 "Please report your usecase to linux-mm@kvack.org if you "
3795 "depend on this functionality.\n");
3796 ret = memcg_update_kmem_max(memcg, nr_pages);
3799 ret = memcg_update_tcp_max(memcg, nr_pages);
3803 case RES_SOFT_LIMIT:
3804 memcg->soft_limit = nr_pages;
3808 return ret ?: nbytes;
3811 static ssize_t mem_cgroup_reset(struct kernfs_open_file *of, char *buf,
3812 size_t nbytes, loff_t off)
3814 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
3815 struct page_counter *counter;
3817 switch (MEMFILE_TYPE(of_cft(of)->private)) {
3819 counter = &memcg->memory;
3822 counter = &memcg->memsw;
3825 counter = &memcg->kmem;
3828 counter = &memcg->tcpmem;
3834 switch (MEMFILE_ATTR(of_cft(of)->private)) {
3836 page_counter_reset_watermark(counter);
3839 counter->failcnt = 0;
3848 static u64 mem_cgroup_move_charge_read(struct cgroup_subsys_state *css,
3851 return mem_cgroup_from_css(css)->move_charge_at_immigrate;
3855 static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css,
3856 struct cftype *cft, u64 val)
3858 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
3860 if (val & ~MOVE_MASK)
3864 * No kind of locking is needed in here, because ->can_attach() will
3865 * check this value once in the beginning of the process, and then carry
3866 * on with stale data. This means that changes to this value will only
3867 * affect task migrations starting after the change.
3869 memcg->move_charge_at_immigrate = val;
3873 static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css,
3874 struct cftype *cft, u64 val)
3882 #define LRU_ALL_FILE (BIT(LRU_INACTIVE_FILE) | BIT(LRU_ACTIVE_FILE))
3883 #define LRU_ALL_ANON (BIT(LRU_INACTIVE_ANON) | BIT(LRU_ACTIVE_ANON))
3884 #define LRU_ALL ((1 << NR_LRU_LISTS) - 1)
3886 static unsigned long mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg,
3887 int nid, unsigned int lru_mask, bool tree)
3889 struct lruvec *lruvec = mem_cgroup_lruvec(memcg, NODE_DATA(nid));
3890 unsigned long nr = 0;
3893 VM_BUG_ON((unsigned)nid >= nr_node_ids);
3896 if (!(BIT(lru) & lru_mask))
3899 nr += lruvec_page_state(lruvec, NR_LRU_BASE + lru);
3901 nr += lruvec_page_state_local(lruvec, NR_LRU_BASE + lru);
3906 static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup *memcg,
3907 unsigned int lru_mask,
3910 unsigned long nr = 0;
3914 if (!(BIT(lru) & lru_mask))
3917 nr += memcg_page_state(memcg, NR_LRU_BASE + lru);
3919 nr += memcg_page_state_local(memcg, NR_LRU_BASE + lru);
3924 static int memcg_numa_stat_show(struct seq_file *m, void *v)
3928 unsigned int lru_mask;
3931 static const struct numa_stat stats[] = {
3932 { "total", LRU_ALL },
3933 { "file", LRU_ALL_FILE },
3934 { "anon", LRU_ALL_ANON },
3935 { "unevictable", BIT(LRU_UNEVICTABLE) },
3937 const struct numa_stat *stat;
3939 struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
3941 mem_cgroup_flush_stats();
3943 for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) {
3944 seq_printf(m, "%s=%lu", stat->name,
3945 mem_cgroup_nr_lru_pages(memcg, stat->lru_mask,
3947 for_each_node_state(nid, N_MEMORY)
3948 seq_printf(m, " N%d=%lu", nid,
3949 mem_cgroup_node_nr_lru_pages(memcg, nid,
3950 stat->lru_mask, false));
3954 for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) {
3956 seq_printf(m, "hierarchical_%s=%lu", stat->name,
3957 mem_cgroup_nr_lru_pages(memcg, stat->lru_mask,
3959 for_each_node_state(nid, N_MEMORY)
3960 seq_printf(m, " N%d=%lu", nid,
3961 mem_cgroup_node_nr_lru_pages(memcg, nid,
3962 stat->lru_mask, true));
3968 #endif /* CONFIG_NUMA */
3970 static const unsigned int memcg1_stats[] = {
3973 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
3983 static const char *const memcg1_stat_names[] = {
3986 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
3996 /* Universal VM events cgroup1 shows, original sort order */
3997 static const unsigned int memcg1_events[] = {
4004 static int memcg_stat_show(struct seq_file *m, void *v)
4006 struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
4007 unsigned long memory, memsw;
4008 struct mem_cgroup *mi;
4011 BUILD_BUG_ON(ARRAY_SIZE(memcg1_stat_names) != ARRAY_SIZE(memcg1_stats));
4013 mem_cgroup_flush_stats();
4015 for (i = 0; i < ARRAY_SIZE(memcg1_stats); i++) {
4018 if (memcg1_stats[i] == MEMCG_SWAP && !do_memsw_account())
4020 nr = memcg_page_state_local(memcg, memcg1_stats[i]);
4021 seq_printf(m, "%s %lu\n", memcg1_stat_names[i], nr * PAGE_SIZE);
4024 for (i = 0; i < ARRAY_SIZE(memcg1_events); i++)
4025 seq_printf(m, "%s %lu\n", vm_event_name(memcg1_events[i]),
4026 memcg_events_local(memcg, memcg1_events[i]));
4028 for (i = 0; i < NR_LRU_LISTS; i++)
4029 seq_printf(m, "%s %lu\n", lru_list_name(i),
4030 memcg_page_state_local(memcg, NR_LRU_BASE + i) *
4033 /* Hierarchical information */
4034 memory = memsw = PAGE_COUNTER_MAX;
4035 for (mi = memcg; mi; mi = parent_mem_cgroup(mi)) {
4036 memory = min(memory, READ_ONCE(mi->memory.max));
4037 memsw = min(memsw, READ_ONCE(mi->memsw.max));
4039 seq_printf(m, "hierarchical_memory_limit %llu\n",
4040 (u64)memory * PAGE_SIZE);
4041 if (do_memsw_account())
4042 seq_printf(m, "hierarchical_memsw_limit %llu\n",
4043 (u64)memsw * PAGE_SIZE);
4045 for (i = 0; i < ARRAY_SIZE(memcg1_stats); i++) {
4048 if (memcg1_stats[i] == MEMCG_SWAP && !do_memsw_account())
4050 nr = memcg_page_state(memcg, memcg1_stats[i]);
4051 seq_printf(m, "total_%s %llu\n", memcg1_stat_names[i],
4052 (u64)nr * PAGE_SIZE);
4055 for (i = 0; i < ARRAY_SIZE(memcg1_events); i++)
4056 seq_printf(m, "total_%s %llu\n",
4057 vm_event_name(memcg1_events[i]),
4058 (u64)memcg_events(memcg, memcg1_events[i]));
4060 for (i = 0; i < NR_LRU_LISTS; i++)
4061 seq_printf(m, "total_%s %llu\n", lru_list_name(i),
4062 (u64)memcg_page_state(memcg, NR_LRU_BASE + i) *
4065 #ifdef CONFIG_DEBUG_VM
4068 struct mem_cgroup_per_node *mz;
4069 unsigned long anon_cost = 0;
4070 unsigned long file_cost = 0;
4072 for_each_online_pgdat(pgdat) {
4073 mz = memcg->nodeinfo[pgdat->node_id];
4075 anon_cost += mz->lruvec.anon_cost;
4076 file_cost += mz->lruvec.file_cost;
4078 seq_printf(m, "anon_cost %lu\n", anon_cost);
4079 seq_printf(m, "file_cost %lu\n", file_cost);
4086 static u64 mem_cgroup_swappiness_read(struct cgroup_subsys_state *css,
4089 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4091 return mem_cgroup_swappiness(memcg);
4094 static int mem_cgroup_swappiness_write(struct cgroup_subsys_state *css,
4095 struct cftype *cft, u64 val)
4097 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4102 if (!mem_cgroup_is_root(memcg))
4103 memcg->swappiness = val;
4105 vm_swappiness = val;
4110 static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap)
4112 struct mem_cgroup_threshold_ary *t;
4113 unsigned long usage;
4118 t = rcu_dereference(memcg->thresholds.primary);
4120 t = rcu_dereference(memcg->memsw_thresholds.primary);
4125 usage = mem_cgroup_usage(memcg, swap);
4128 * current_threshold points to threshold just below or equal to usage.
4129 * If it's not true, a threshold was crossed after last
4130 * call of __mem_cgroup_threshold().
4132 i = t->current_threshold;
4135 * Iterate backward over array of thresholds starting from
4136 * current_threshold and check if a threshold is crossed.
4137 * If none of thresholds below usage is crossed, we read
4138 * only one element of the array here.
4140 for (; i >= 0 && unlikely(t->entries[i].threshold > usage); i--)
4141 eventfd_signal(t->entries[i].eventfd, 1);
4143 /* i = current_threshold + 1 */
4147 * Iterate forward over array of thresholds starting from
4148 * current_threshold+1 and check if a threshold is crossed.
4149 * If none of thresholds above usage is crossed, we read
4150 * only one element of the array here.
4152 for (; i < t->size && unlikely(t->entries[i].threshold <= usage); i++)
4153 eventfd_signal(t->entries[i].eventfd, 1);
4155 /* Update current_threshold */
4156 t->current_threshold = i - 1;
4161 static void mem_cgroup_threshold(struct mem_cgroup *memcg)
4164 __mem_cgroup_threshold(memcg, false);
4165 if (do_memsw_account())
4166 __mem_cgroup_threshold(memcg, true);
4168 memcg = parent_mem_cgroup(memcg);
4172 static int compare_thresholds(const void *a, const void *b)
4174 const struct mem_cgroup_threshold *_a = a;
4175 const struct mem_cgroup_threshold *_b = b;
4177 if (_a->threshold > _b->threshold)
4180 if (_a->threshold < _b->threshold)
4186 static int mem_cgroup_oom_notify_cb(struct mem_cgroup *memcg)
4188 struct mem_cgroup_eventfd_list *ev;
4190 spin_lock(&memcg_oom_lock);
4192 list_for_each_entry(ev, &memcg->oom_notify, list)
4193 eventfd_signal(ev->eventfd, 1);
4195 spin_unlock(&memcg_oom_lock);
4199 static void mem_cgroup_oom_notify(struct mem_cgroup *memcg)
4201 struct mem_cgroup *iter;
4203 for_each_mem_cgroup_tree(iter, memcg)
4204 mem_cgroup_oom_notify_cb(iter);
4207 static int __mem_cgroup_usage_register_event(struct mem_cgroup *memcg,
4208 struct eventfd_ctx *eventfd, const char *args, enum res_type type)
4210 struct mem_cgroup_thresholds *thresholds;
4211 struct mem_cgroup_threshold_ary *new;
4212 unsigned long threshold;
4213 unsigned long usage;
4216 ret = page_counter_memparse(args, "-1", &threshold);
4220 mutex_lock(&memcg->thresholds_lock);
4223 thresholds = &memcg->thresholds;
4224 usage = mem_cgroup_usage(memcg, false);
4225 } else if (type == _MEMSWAP) {
4226 thresholds = &memcg->memsw_thresholds;
4227 usage = mem_cgroup_usage(memcg, true);
4231 /* Check if a threshold crossed before adding a new one */
4232 if (thresholds->primary)
4233 __mem_cgroup_threshold(memcg, type == _MEMSWAP);
4235 size = thresholds->primary ? thresholds->primary->size + 1 : 1;
4237 /* Allocate memory for new array of thresholds */
4238 new = kmalloc(struct_size(new, entries, size), GFP_KERNEL);
4245 /* Copy thresholds (if any) to new array */
4246 if (thresholds->primary)
4247 memcpy(new->entries, thresholds->primary->entries,
4248 flex_array_size(new, entries, size - 1));
4250 /* Add new threshold */
4251 new->entries[size - 1].eventfd = eventfd;
4252 new->entries[size - 1].threshold = threshold;
4254 /* Sort thresholds. Registering of new threshold isn't time-critical */
4255 sort(new->entries, size, sizeof(*new->entries),
4256 compare_thresholds, NULL);
4258 /* Find current threshold */
4259 new->current_threshold = -1;
4260 for (i = 0; i < size; i++) {
4261 if (new->entries[i].threshold <= usage) {
4263 * new->current_threshold will not be used until
4264 * rcu_assign_pointer(), so it's safe to increment
4267 ++new->current_threshold;
4272 /* Free old spare buffer and save old primary buffer as spare */
4273 kfree(thresholds->spare);
4274 thresholds->spare = thresholds->primary;
4276 rcu_assign_pointer(thresholds->primary, new);
4278 /* To be sure that nobody uses thresholds */
4282 mutex_unlock(&memcg->thresholds_lock);
4287 static int mem_cgroup_usage_register_event(struct mem_cgroup *memcg,
4288 struct eventfd_ctx *eventfd, const char *args)
4290 return __mem_cgroup_usage_register_event(memcg, eventfd, args, _MEM);
4293 static int memsw_cgroup_usage_register_event(struct mem_cgroup *memcg,
4294 struct eventfd_ctx *eventfd, const char *args)
4296 return __mem_cgroup_usage_register_event(memcg, eventfd, args, _MEMSWAP);
4299 static void __mem_cgroup_usage_unregister_event(struct mem_cgroup *memcg,
4300 struct eventfd_ctx *eventfd, enum res_type type)
4302 struct mem_cgroup_thresholds *thresholds;
4303 struct mem_cgroup_threshold_ary *new;
4304 unsigned long usage;
4305 int i, j, size, entries;
4307 mutex_lock(&memcg->thresholds_lock);
4310 thresholds = &memcg->thresholds;
4311 usage = mem_cgroup_usage(memcg, false);
4312 } else if (type == _MEMSWAP) {
4313 thresholds = &memcg->memsw_thresholds;
4314 usage = mem_cgroup_usage(memcg, true);
4318 if (!thresholds->primary)
4321 /* Check if a threshold crossed before removing */
4322 __mem_cgroup_threshold(memcg, type == _MEMSWAP);
4324 /* Calculate new number of threshold */
4326 for (i = 0; i < thresholds->primary->size; i++) {
4327 if (thresholds->primary->entries[i].eventfd != eventfd)
4333 new = thresholds->spare;
4335 /* If no items related to eventfd have been cleared, nothing to do */
4339 /* Set thresholds array to NULL if we don't have thresholds */
4348 /* Copy thresholds and find current threshold */
4349 new->current_threshold = -1;
4350 for (i = 0, j = 0; i < thresholds->primary->size; i++) {
4351 if (thresholds->primary->entries[i].eventfd == eventfd)
4354 new->entries[j] = thresholds->primary->entries[i];
4355 if (new->entries[j].threshold <= usage) {
4357 * new->current_threshold will not be used
4358 * until rcu_assign_pointer(), so it's safe to increment
4361 ++new->current_threshold;
4367 /* Swap primary and spare array */
4368 thresholds->spare = thresholds->primary;
4370 rcu_assign_pointer(thresholds->primary, new);
4372 /* To be sure that nobody uses thresholds */
4375 /* If all events are unregistered, free the spare array */
4377 kfree(thresholds->spare);
4378 thresholds->spare = NULL;
4381 mutex_unlock(&memcg->thresholds_lock);
4384 static void mem_cgroup_usage_unregister_event(struct mem_cgroup *memcg,
4385 struct eventfd_ctx *eventfd)
4387 return __mem_cgroup_usage_unregister_event(memcg, eventfd, _MEM);
4390 static void memsw_cgroup_usage_unregister_event(struct mem_cgroup *memcg,
4391 struct eventfd_ctx *eventfd)
4393 return __mem_cgroup_usage_unregister_event(memcg, eventfd, _MEMSWAP);
4396 static int mem_cgroup_oom_register_event(struct mem_cgroup *memcg,
4397 struct eventfd_ctx *eventfd, const char *args)
4399 struct mem_cgroup_eventfd_list *event;
4401 event = kmalloc(sizeof(*event), GFP_KERNEL);
4405 spin_lock(&memcg_oom_lock);
4407 event->eventfd = eventfd;
4408 list_add(&event->list, &memcg->oom_notify);
4410 /* already in OOM ? */
4411 if (memcg->under_oom)
4412 eventfd_signal(eventfd, 1);
4413 spin_unlock(&memcg_oom_lock);
4418 static void mem_cgroup_oom_unregister_event(struct mem_cgroup *memcg,
4419 struct eventfd_ctx *eventfd)
4421 struct mem_cgroup_eventfd_list *ev, *tmp;
4423 spin_lock(&memcg_oom_lock);
4425 list_for_each_entry_safe(ev, tmp, &memcg->oom_notify, list) {
4426 if (ev->eventfd == eventfd) {
4427 list_del(&ev->list);
4432 spin_unlock(&memcg_oom_lock);
4435 static int mem_cgroup_oom_control_read(struct seq_file *sf, void *v)
4437 struct mem_cgroup *memcg = mem_cgroup_from_seq(sf);
4439 seq_printf(sf, "oom_kill_disable %d\n", memcg->oom_kill_disable);
4440 seq_printf(sf, "under_oom %d\n", (bool)memcg->under_oom);
4441 seq_printf(sf, "oom_kill %lu\n",
4442 atomic_long_read(&memcg->memory_events[MEMCG_OOM_KILL]));
4446 static int mem_cgroup_oom_control_write(struct cgroup_subsys_state *css,
4447 struct cftype *cft, u64 val)
4449 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4451 /* cannot set to root cgroup and only 0 and 1 are allowed */
4452 if (mem_cgroup_is_root(memcg) || !((val == 0) || (val == 1)))
4455 memcg->oom_kill_disable = val;
4457 memcg_oom_recover(memcg);
4462 #ifdef CONFIG_CGROUP_WRITEBACK
4464 #include <trace/events/writeback.h>
4466 static int memcg_wb_domain_init(struct mem_cgroup *memcg, gfp_t gfp)
4468 return wb_domain_init(&memcg->cgwb_domain, gfp);
4471 static void memcg_wb_domain_exit(struct mem_cgroup *memcg)
4473 wb_domain_exit(&memcg->cgwb_domain);
4476 static void memcg_wb_domain_size_changed(struct mem_cgroup *memcg)
4478 wb_domain_size_changed(&memcg->cgwb_domain);
4481 struct wb_domain *mem_cgroup_wb_domain(struct bdi_writeback *wb)
4483 struct mem_cgroup *memcg = mem_cgroup_from_css(wb->memcg_css);
4485 if (!memcg->css.parent)
4488 return &memcg->cgwb_domain;
4492 * mem_cgroup_wb_stats - retrieve writeback related stats from its memcg
4493 * @wb: bdi_writeback in question
4494 * @pfilepages: out parameter for number of file pages
4495 * @pheadroom: out parameter for number of allocatable pages according to memcg
4496 * @pdirty: out parameter for number of dirty pages
4497 * @pwriteback: out parameter for number of pages under writeback
4499 * Determine the numbers of file, headroom, dirty, and writeback pages in
4500 * @wb's memcg. File, dirty and writeback are self-explanatory. Headroom
4501 * is a bit more involved.
4503 * A memcg's headroom is "min(max, high) - used". In the hierarchy, the
4504 * headroom is calculated as the lowest headroom of itself and the
4505 * ancestors. Note that this doesn't consider the actual amount of
4506 * available memory in the system. The caller should further cap
4507 * *@pheadroom accordingly.
4509 void mem_cgroup_wb_stats(struct bdi_writeback *wb, unsigned long *pfilepages,
4510 unsigned long *pheadroom, unsigned long *pdirty,
4511 unsigned long *pwriteback)
4513 struct mem_cgroup *memcg = mem_cgroup_from_css(wb->memcg_css);
4514 struct mem_cgroup *parent;
4516 mem_cgroup_flush_stats();
4518 *pdirty = memcg_page_state(memcg, NR_FILE_DIRTY);
4519 *pwriteback = memcg_page_state(memcg, NR_WRITEBACK);
4520 *pfilepages = memcg_page_state(memcg, NR_INACTIVE_FILE) +
4521 memcg_page_state(memcg, NR_ACTIVE_FILE);
4523 *pheadroom = PAGE_COUNTER_MAX;
4524 while ((parent = parent_mem_cgroup(memcg))) {
4525 unsigned long ceiling = min(READ_ONCE(memcg->memory.max),
4526 READ_ONCE(memcg->memory.high));
4527 unsigned long used = page_counter_read(&memcg->memory);
4529 *pheadroom = min(*pheadroom, ceiling - min(ceiling, used));
4535 * Foreign dirty flushing
4537 * There's an inherent mismatch between memcg and writeback. The former
4538 * tracks ownership per-page while the latter per-inode. This was a
4539 * deliberate design decision because honoring per-page ownership in the
4540 * writeback path is complicated, may lead to higher CPU and IO overheads
4541 * and deemed unnecessary given that write-sharing an inode across
4542 * different cgroups isn't a common use-case.
4544 * Combined with inode majority-writer ownership switching, this works well
4545 * enough in most cases but there are some pathological cases. For
4546 * example, let's say there are two cgroups A and B which keep writing to
4547 * different but confined parts of the same inode. B owns the inode and
4548 * A's memory is limited far below B's. A's dirty ratio can rise enough to
4549 * trigger balance_dirty_pages() sleeps but B's can be low enough to avoid
4550 * triggering background writeback. A will be slowed down without a way to
4551 * make writeback of the dirty pages happen.
4553 * Conditions like the above can lead to a cgroup getting repeatedly and
4554 * severely throttled after making some progress after each
4555 * dirty_expire_interval while the underlying IO device is almost
4558 * Solving this problem completely requires matching the ownership tracking
4559 * granularities between memcg and writeback in either direction. However,
4560 * the more egregious behaviors can be avoided by simply remembering the
4561 * most recent foreign dirtying events and initiating remote flushes on
4562 * them when local writeback isn't enough to keep the memory clean enough.
4564 * The following two functions implement such mechanism. When a foreign
4565 * page - a page whose memcg and writeback ownerships don't match - is
4566 * dirtied, mem_cgroup_track_foreign_dirty() records the inode owning
4567 * bdi_writeback on the page owning memcg. When balance_dirty_pages()
4568 * decides that the memcg needs to sleep due to high dirty ratio, it calls
4569 * mem_cgroup_flush_foreign() which queues writeback on the recorded
4570 * foreign bdi_writebacks which haven't expired. Both the numbers of
4571 * recorded bdi_writebacks and concurrent in-flight foreign writebacks are
4572 * limited to MEMCG_CGWB_FRN_CNT.
4574 * The mechanism only remembers IDs and doesn't hold any object references.
4575 * As being wrong occasionally doesn't matter, updates and accesses to the
4576 * records are lockless and racy.
4578 void mem_cgroup_track_foreign_dirty_slowpath(struct page *page,
4579 struct bdi_writeback *wb)
4581 struct mem_cgroup *memcg = page_memcg(page);
4582 struct memcg_cgwb_frn *frn;
4583 u64 now = get_jiffies_64();
4584 u64 oldest_at = now;
4588 trace_track_foreign_dirty(page, wb);
4591 * Pick the slot to use. If there is already a slot for @wb, keep
4592 * using it. If not replace the oldest one which isn't being
4595 for (i = 0; i < MEMCG_CGWB_FRN_CNT; i++) {
4596 frn = &memcg->cgwb_frn[i];
4597 if (frn->bdi_id == wb->bdi->id &&
4598 frn->memcg_id == wb->memcg_css->id)
4600 if (time_before64(frn->at, oldest_at) &&
4601 atomic_read(&frn->done.cnt) == 1) {
4603 oldest_at = frn->at;
4607 if (i < MEMCG_CGWB_FRN_CNT) {
4609 * Re-using an existing one. Update timestamp lazily to
4610 * avoid making the cacheline hot. We want them to be
4611 * reasonably up-to-date and significantly shorter than
4612 * dirty_expire_interval as that's what expires the record.
4613 * Use the shorter of 1s and dirty_expire_interval / 8.
4615 unsigned long update_intv =
4616 min_t(unsigned long, HZ,
4617 msecs_to_jiffies(dirty_expire_interval * 10) / 8);
4619 if (time_before64(frn->at, now - update_intv))
4621 } else if (oldest >= 0) {
4622 /* replace the oldest free one */
4623 frn = &memcg->cgwb_frn[oldest];
4624 frn->bdi_id = wb->bdi->id;
4625 frn->memcg_id = wb->memcg_css->id;
4630 /* issue foreign writeback flushes for recorded foreign dirtying events */
4631 void mem_cgroup_flush_foreign(struct bdi_writeback *wb)
4633 struct mem_cgroup *memcg = mem_cgroup_from_css(wb->memcg_css);
4634 unsigned long intv = msecs_to_jiffies(dirty_expire_interval * 10);
4635 u64 now = jiffies_64;
4638 for (i = 0; i < MEMCG_CGWB_FRN_CNT; i++) {
4639 struct memcg_cgwb_frn *frn = &memcg->cgwb_frn[i];
4642 * If the record is older than dirty_expire_interval,
4643 * writeback on it has already started. No need to kick it
4644 * off again. Also, don't start a new one if there's
4645 * already one in flight.
4647 if (time_after64(frn->at, now - intv) &&
4648 atomic_read(&frn->done.cnt) == 1) {
4650 trace_flush_foreign(wb, frn->bdi_id, frn->memcg_id);
4651 cgroup_writeback_by_id(frn->bdi_id, frn->memcg_id,
4652 WB_REASON_FOREIGN_FLUSH,
4658 #else /* CONFIG_CGROUP_WRITEBACK */
4660 static int memcg_wb_domain_init(struct mem_cgroup *memcg, gfp_t gfp)
4665 static void memcg_wb_domain_exit(struct mem_cgroup *memcg)
4669 static void memcg_wb_domain_size_changed(struct mem_cgroup *memcg)
4673 #endif /* CONFIG_CGROUP_WRITEBACK */
4676 * DO NOT USE IN NEW FILES.
4678 * "cgroup.event_control" implementation.
4680 * This is way over-engineered. It tries to support fully configurable
4681 * events for each user. Such level of flexibility is completely
4682 * unnecessary especially in the light of the planned unified hierarchy.
4684 * Please deprecate this and replace with something simpler if at all
4689 * Unregister event and free resources.
4691 * Gets called from workqueue.
4693 static void memcg_event_remove(struct work_struct *work)
4695 struct mem_cgroup_event *event =
4696 container_of(work, struct mem_cgroup_event, remove);
4697 struct mem_cgroup *memcg = event->memcg;
4699 remove_wait_queue(event->wqh, &event->wait);
4701 event->unregister_event(memcg, event->eventfd);
4703 /* Notify userspace the event is going away. */
4704 eventfd_signal(event->eventfd, 1);
4706 eventfd_ctx_put(event->eventfd);
4708 css_put(&memcg->css);
4712 * Gets called on EPOLLHUP on eventfd when user closes it.
4714 * Called with wqh->lock held and interrupts disabled.
4716 static int memcg_event_wake(wait_queue_entry_t *wait, unsigned mode,
4717 int sync, void *key)
4719 struct mem_cgroup_event *event =
4720 container_of(wait, struct mem_cgroup_event, wait);
4721 struct mem_cgroup *memcg = event->memcg;
4722 __poll_t flags = key_to_poll(key);
4724 if (flags & EPOLLHUP) {
4726 * If the event has been detached at cgroup removal, we
4727 * can simply return knowing the other side will cleanup
4730 * We can't race against event freeing since the other
4731 * side will require wqh->lock via remove_wait_queue(),
4734 spin_lock(&memcg->event_list_lock);
4735 if (!list_empty(&event->list)) {
4736 list_del_init(&event->list);
4738 * We are in atomic context, but cgroup_event_remove()
4739 * may sleep, so we have to call it in workqueue.
4741 schedule_work(&event->remove);
4743 spin_unlock(&memcg->event_list_lock);
4749 static void memcg_event_ptable_queue_proc(struct file *file,
4750 wait_queue_head_t *wqh, poll_table *pt)
4752 struct mem_cgroup_event *event =
4753 container_of(pt, struct mem_cgroup_event, pt);
4756 add_wait_queue(wqh, &event->wait);
4760 * DO NOT USE IN NEW FILES.
4762 * Parse input and register new cgroup event handler.
4764 * Input must be in format '<event_fd> <control_fd> <args>'.
4765 * Interpretation of args is defined by control file implementation.
4767 static ssize_t memcg_write_event_control(struct kernfs_open_file *of,
4768 char *buf, size_t nbytes, loff_t off)
4770 struct cgroup_subsys_state *css = of_css(of);
4771 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4772 struct mem_cgroup_event *event;
4773 struct cgroup_subsys_state *cfile_css;
4774 unsigned int efd, cfd;
4781 buf = strstrip(buf);
4783 efd = simple_strtoul(buf, &endp, 10);
4788 cfd = simple_strtoul(buf, &endp, 10);
4789 if ((*endp != ' ') && (*endp != '\0'))
4793 event = kzalloc(sizeof(*event), GFP_KERNEL);
4797 event->memcg = memcg;
4798 INIT_LIST_HEAD(&event->list);
4799 init_poll_funcptr(&event->pt, memcg_event_ptable_queue_proc);
4800 init_waitqueue_func_entry(&event->wait, memcg_event_wake);
4801 INIT_WORK(&event->remove, memcg_event_remove);
4809 event->eventfd = eventfd_ctx_fileget(efile.file);
4810 if (IS_ERR(event->eventfd)) {
4811 ret = PTR_ERR(event->eventfd);
4818 goto out_put_eventfd;
4821 /* the process need read permission on control file */
4822 /* AV: shouldn't we check that it's been opened for read instead? */
4823 ret = file_permission(cfile.file, MAY_READ);
4828 * Determine the event callbacks and set them in @event. This used
4829 * to be done via struct cftype but cgroup core no longer knows
4830 * about these events. The following is crude but the whole thing
4831 * is for compatibility anyway.
4833 * DO NOT ADD NEW FILES.
4835 name = cfile.file->f_path.dentry->d_name.name;
4837 if (!strcmp(name, "memory.usage_in_bytes")) {
4838 event->register_event = mem_cgroup_usage_register_event;
4839 event->unregister_event = mem_cgroup_usage_unregister_event;
4840 } else if (!strcmp(name, "memory.oom_control")) {
4841 event->register_event = mem_cgroup_oom_register_event;
4842 event->unregister_event = mem_cgroup_oom_unregister_event;
4843 } else if (!strcmp(name, "memory.pressure_level")) {
4844 event->register_event = vmpressure_register_event;
4845 event->unregister_event = vmpressure_unregister_event;
4846 } else if (!strcmp(name, "memory.memsw.usage_in_bytes")) {
4847 event->register_event = memsw_cgroup_usage_register_event;
4848 event->unregister_event = memsw_cgroup_usage_unregister_event;
4855 * Verify @cfile should belong to @css. Also, remaining events are
4856 * automatically removed on cgroup destruction but the removal is
4857 * asynchronous, so take an extra ref on @css.
4859 cfile_css = css_tryget_online_from_dir(cfile.file->f_path.dentry->d_parent,
4860 &memory_cgrp_subsys);
4862 if (IS_ERR(cfile_css))
4864 if (cfile_css != css) {
4869 ret = event->register_event(memcg, event->eventfd, buf);
4873 vfs_poll(efile.file, &event->pt);
4875 spin_lock_irq(&memcg->event_list_lock);
4876 list_add(&event->list, &memcg->event_list);
4877 spin_unlock_irq(&memcg->event_list_lock);
4889 eventfd_ctx_put(event->eventfd);
4898 static struct cftype mem_cgroup_legacy_files[] = {
4900 .name = "usage_in_bytes",
4901 .private = MEMFILE_PRIVATE(_MEM, RES_USAGE),
4902 .read_u64 = mem_cgroup_read_u64,
4905 .name = "max_usage_in_bytes",
4906 .private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE),
4907 .write = mem_cgroup_reset,
4908 .read_u64 = mem_cgroup_read_u64,
4911 .name = "limit_in_bytes",
4912 .private = MEMFILE_PRIVATE(_MEM, RES_LIMIT),
4913 .write = mem_cgroup_write,
4914 .read_u64 = mem_cgroup_read_u64,
4917 .name = "soft_limit_in_bytes",
4918 .private = MEMFILE_PRIVATE(_MEM, RES_SOFT_LIMIT),
4919 .write = mem_cgroup_write,
4920 .read_u64 = mem_cgroup_read_u64,
4924 .private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT),
4925 .write = mem_cgroup_reset,
4926 .read_u64 = mem_cgroup_read_u64,
4930 .seq_show = memcg_stat_show,
4933 .name = "force_empty",
4934 .write = mem_cgroup_force_empty_write,
4937 .name = "use_hierarchy",
4938 .write_u64 = mem_cgroup_hierarchy_write,
4939 .read_u64 = mem_cgroup_hierarchy_read,
4942 .name = "cgroup.event_control", /* XXX: for compat */
4943 .write = memcg_write_event_control,
4944 .flags = CFTYPE_NO_PREFIX | CFTYPE_WORLD_WRITABLE,
4947 .name = "swappiness",
4948 .read_u64 = mem_cgroup_swappiness_read,
4949 .write_u64 = mem_cgroup_swappiness_write,
4952 .name = "move_charge_at_immigrate",
4953 .read_u64 = mem_cgroup_move_charge_read,
4954 .write_u64 = mem_cgroup_move_charge_write,
4957 .name = "oom_control",
4958 .seq_show = mem_cgroup_oom_control_read,
4959 .write_u64 = mem_cgroup_oom_control_write,
4960 .private = MEMFILE_PRIVATE(_OOM_TYPE, OOM_CONTROL),
4963 .name = "pressure_level",
4967 .name = "numa_stat",
4968 .seq_show = memcg_numa_stat_show,
4972 .name = "kmem.limit_in_bytes",
4973 .private = MEMFILE_PRIVATE(_KMEM, RES_LIMIT),
4974 .write = mem_cgroup_write,
4975 .read_u64 = mem_cgroup_read_u64,
4978 .name = "kmem.usage_in_bytes",
4979 .private = MEMFILE_PRIVATE(_KMEM, RES_USAGE),
4980 .read_u64 = mem_cgroup_read_u64,
4983 .name = "kmem.failcnt",
4984 .private = MEMFILE_PRIVATE(_KMEM, RES_FAILCNT),
4985 .write = mem_cgroup_reset,
4986 .read_u64 = mem_cgroup_read_u64,
4989 .name = "kmem.max_usage_in_bytes",
4990 .private = MEMFILE_PRIVATE(_KMEM, RES_MAX_USAGE),
4991 .write = mem_cgroup_reset,
4992 .read_u64 = mem_cgroup_read_u64,
4994 #if defined(CONFIG_MEMCG_KMEM) && \
4995 (defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG))
4997 .name = "kmem.slabinfo",
4998 .seq_show = memcg_slab_show,
5002 .name = "kmem.tcp.limit_in_bytes",
5003 .private = MEMFILE_PRIVATE(_TCP, RES_LIMIT),
5004 .write = mem_cgroup_write,
5005 .read_u64 = mem_cgroup_read_u64,
5008 .name = "kmem.tcp.usage_in_bytes",
5009 .private = MEMFILE_PRIVATE(_TCP, RES_USAGE),
5010 .read_u64 = mem_cgroup_read_u64,
5013 .name = "kmem.tcp.failcnt",
5014 .private = MEMFILE_PRIVATE(_TCP, RES_FAILCNT),
5015 .write = mem_cgroup_reset,
5016 .read_u64 = mem_cgroup_read_u64,
5019 .name = "kmem.tcp.max_usage_in_bytes",
5020 .private = MEMFILE_PRIVATE(_TCP, RES_MAX_USAGE),
5021 .write = mem_cgroup_reset,
5022 .read_u64 = mem_cgroup_read_u64,
5024 { }, /* terminate */
5028 * Private memory cgroup IDR
5030 * Swap-out records and page cache shadow entries need to store memcg
5031 * references in constrained space, so we maintain an ID space that is
5032 * limited to 16 bit (MEM_CGROUP_ID_MAX), limiting the total number of
5033 * memory-controlled cgroups to 64k.
5035 * However, there usually are many references to the offline CSS after
5036 * the cgroup has been destroyed, such as page cache or reclaimable
5037 * slab objects, that don't need to hang on to the ID. We want to keep
5038 * those dead CSS from occupying IDs, or we might quickly exhaust the
5039 * relatively small ID space and prevent the creation of new cgroups
5040 * even when there are much fewer than 64k cgroups - possibly none.
5042 * Maintain a private 16-bit ID space for memcg, and allow the ID to
5043 * be freed and recycled when it's no longer needed, which is usually
5044 * when the CSS is offlined.
5046 * The only exception to that are records of swapped out tmpfs/shmem
5047 * pages that need to be attributed to live ancestors on swapin. But
5048 * those references are manageable from userspace.
5051 static DEFINE_IDR(mem_cgroup_idr);
5053 static void mem_cgroup_id_remove(struct mem_cgroup *memcg)
5055 if (memcg->id.id > 0) {
5056 idr_remove(&mem_cgroup_idr, memcg->id.id);
5061 static void __maybe_unused mem_cgroup_id_get_many(struct mem_cgroup *memcg,
5064 refcount_add(n, &memcg->id.ref);
5067 static void mem_cgroup_id_put_many(struct mem_cgroup *memcg, unsigned int n)
5069 if (refcount_sub_and_test(n, &memcg->id.ref)) {
5070 mem_cgroup_id_remove(memcg);
5072 /* Memcg ID pins CSS */
5073 css_put(&memcg->css);
5077 static inline void mem_cgroup_id_put(struct mem_cgroup *memcg)
5079 mem_cgroup_id_put_many(memcg, 1);
5083 * mem_cgroup_from_id - look up a memcg from a memcg id
5084 * @id: the memcg id to look up
5086 * Caller must hold rcu_read_lock().
5088 struct mem_cgroup *mem_cgroup_from_id(unsigned short id)
5090 WARN_ON_ONCE(!rcu_read_lock_held());
5091 return idr_find(&mem_cgroup_idr, id);
5094 static int alloc_mem_cgroup_per_node_info(struct mem_cgroup *memcg, int node)
5096 struct mem_cgroup_per_node *pn;
5099 * This routine is called against possible nodes.
5100 * But it's BUG to call kmalloc() against offline node.
5102 * TODO: this routine can waste much memory for nodes which will
5103 * never be onlined. It's better to use memory hotplug callback
5106 if (!node_state(node, N_NORMAL_MEMORY))
5108 pn = kzalloc_node(sizeof(*pn), GFP_KERNEL, tmp);
5112 pn->lruvec_stats_percpu = alloc_percpu_gfp(struct lruvec_stats_percpu,
5113 GFP_KERNEL_ACCOUNT);
5114 if (!pn->lruvec_stats_percpu) {
5119 lruvec_init(&pn->lruvec);
5120 pn->usage_in_excess = 0;
5121 pn->on_tree = false;
5124 memcg->nodeinfo[node] = pn;
5128 static void free_mem_cgroup_per_node_info(struct mem_cgroup *memcg, int node)
5130 struct mem_cgroup_per_node *pn = memcg->nodeinfo[node];
5135 free_percpu(pn->lruvec_stats_percpu);
5139 static void __mem_cgroup_free(struct mem_cgroup *memcg)
5144 free_mem_cgroup_per_node_info(memcg, node);
5145 free_percpu(memcg->vmstats_percpu);
5149 static void mem_cgroup_free(struct mem_cgroup *memcg)
5151 memcg_wb_domain_exit(memcg);
5152 __mem_cgroup_free(memcg);
5155 static struct mem_cgroup *mem_cgroup_alloc(void)
5157 struct mem_cgroup *memcg;
5160 int __maybe_unused i;
5161 long error = -ENOMEM;
5163 size = sizeof(struct mem_cgroup);
5164 size += nr_node_ids * sizeof(struct mem_cgroup_per_node *);
5166 memcg = kzalloc(size, GFP_KERNEL);
5168 return ERR_PTR(error);
5170 memcg->id.id = idr_alloc(&mem_cgroup_idr, NULL,
5171 1, MEM_CGROUP_ID_MAX,
5173 if (memcg->id.id < 0) {
5174 error = memcg->id.id;
5178 memcg->vmstats_percpu = alloc_percpu_gfp(struct memcg_vmstats_percpu,
5179 GFP_KERNEL_ACCOUNT);
5180 if (!memcg->vmstats_percpu)
5184 if (alloc_mem_cgroup_per_node_info(memcg, node))
5187 if (memcg_wb_domain_init(memcg, GFP_KERNEL))
5190 INIT_WORK(&memcg->high_work, high_work_func);
5191 INIT_LIST_HEAD(&memcg->oom_notify);
5192 mutex_init(&memcg->thresholds_lock);
5193 spin_lock_init(&memcg->move_lock);
5194 vmpressure_init(&memcg->vmpressure);
5195 INIT_LIST_HEAD(&memcg->event_list);
5196 spin_lock_init(&memcg->event_list_lock);
5197 memcg->socket_pressure = jiffies;
5198 #ifdef CONFIG_MEMCG_KMEM
5199 memcg->kmemcg_id = -1;
5200 INIT_LIST_HEAD(&memcg->objcg_list);
5202 #ifdef CONFIG_CGROUP_WRITEBACK
5203 INIT_LIST_HEAD(&memcg->cgwb_list);
5204 for (i = 0; i < MEMCG_CGWB_FRN_CNT; i++)
5205 memcg->cgwb_frn[i].done =
5206 __WB_COMPLETION_INIT(&memcg_cgwb_frn_waitq);
5208 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
5209 spin_lock_init(&memcg->deferred_split_queue.split_queue_lock);
5210 INIT_LIST_HEAD(&memcg->deferred_split_queue.split_queue);
5211 memcg->deferred_split_queue.split_queue_len = 0;
5213 idr_replace(&mem_cgroup_idr, memcg, memcg->id.id);
5216 mem_cgroup_id_remove(memcg);
5217 __mem_cgroup_free(memcg);
5218 return ERR_PTR(error);
5221 static struct cgroup_subsys_state * __ref
5222 mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
5224 struct mem_cgroup *parent = mem_cgroup_from_css(parent_css);
5225 struct mem_cgroup *memcg, *old_memcg;
5226 long error = -ENOMEM;
5228 old_memcg = set_active_memcg(parent);
5229 memcg = mem_cgroup_alloc();
5230 set_active_memcg(old_memcg);
5232 return ERR_CAST(memcg);
5234 page_counter_set_high(&memcg->memory, PAGE_COUNTER_MAX);
5235 memcg->soft_limit = PAGE_COUNTER_MAX;
5236 page_counter_set_high(&memcg->swap, PAGE_COUNTER_MAX);
5238 memcg->swappiness = mem_cgroup_swappiness(parent);
5239 memcg->oom_kill_disable = parent->oom_kill_disable;
5241 page_counter_init(&memcg->memory, &parent->memory);
5242 page_counter_init(&memcg->swap, &parent->swap);
5243 page_counter_init(&memcg->kmem, &parent->kmem);
5244 page_counter_init(&memcg->tcpmem, &parent->tcpmem);
5246 page_counter_init(&memcg->memory, NULL);
5247 page_counter_init(&memcg->swap, NULL);
5248 page_counter_init(&memcg->kmem, NULL);
5249 page_counter_init(&memcg->tcpmem, NULL);
5251 root_mem_cgroup = memcg;
5255 /* The following stuff does not apply to the root */
5256 error = memcg_online_kmem(memcg);
5260 if (cgroup_subsys_on_dfl(memory_cgrp_subsys) && !cgroup_memory_nosocket)
5261 static_branch_inc(&memcg_sockets_enabled_key);
5265 mem_cgroup_id_remove(memcg);
5266 mem_cgroup_free(memcg);
5267 return ERR_PTR(error);
5270 static int mem_cgroup_css_online(struct cgroup_subsys_state *css)
5272 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5275 * A memcg must be visible for expand_shrinker_info()
5276 * by the time the maps are allocated. So, we allocate maps
5277 * here, when for_each_mem_cgroup() can't skip it.
5279 if (alloc_shrinker_info(memcg)) {
5280 mem_cgroup_id_remove(memcg);
5284 /* Online state pins memcg ID, memcg ID pins CSS */
5285 refcount_set(&memcg->id.ref, 1);
5288 if (unlikely(mem_cgroup_is_root(memcg)))
5289 queue_delayed_work(system_unbound_wq, &stats_flush_dwork,
5294 static void mem_cgroup_css_offline(struct cgroup_subsys_state *css)
5296 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5297 struct mem_cgroup_event *event, *tmp;
5300 * Unregister events and notify userspace.
5301 * Notify userspace about cgroup removing only after rmdir of cgroup
5302 * directory to avoid race between userspace and kernelspace.
5304 spin_lock_irq(&memcg->event_list_lock);
5305 list_for_each_entry_safe(event, tmp, &memcg->event_list, list) {
5306 list_del_init(&event->list);
5307 schedule_work(&event->remove);
5309 spin_unlock_irq(&memcg->event_list_lock);
5311 page_counter_set_min(&memcg->memory, 0);
5312 page_counter_set_low(&memcg->memory, 0);
5314 memcg_offline_kmem(memcg);
5315 reparent_shrinker_deferred(memcg);
5316 wb_memcg_offline(memcg);
5318 drain_all_stock(memcg);
5320 mem_cgroup_id_put(memcg);
5323 static void mem_cgroup_css_released(struct cgroup_subsys_state *css)
5325 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5327 invalidate_reclaim_iterators(memcg);
5330 static void mem_cgroup_css_free(struct cgroup_subsys_state *css)
5332 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5333 int __maybe_unused i;
5335 #ifdef CONFIG_CGROUP_WRITEBACK
5336 for (i = 0; i < MEMCG_CGWB_FRN_CNT; i++)
5337 wb_wait_for_completion(&memcg->cgwb_frn[i].done);
5339 if (cgroup_subsys_on_dfl(memory_cgrp_subsys) && !cgroup_memory_nosocket)
5340 static_branch_dec(&memcg_sockets_enabled_key);
5342 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && memcg->tcpmem_active)
5343 static_branch_dec(&memcg_sockets_enabled_key);
5345 vmpressure_cleanup(&memcg->vmpressure);
5346 cancel_work_sync(&memcg->high_work);
5347 mem_cgroup_remove_from_trees(memcg);
5348 free_shrinker_info(memcg);
5350 /* Need to offline kmem if online_css() fails */
5351 memcg_offline_kmem(memcg);
5352 mem_cgroup_free(memcg);
5356 * mem_cgroup_css_reset - reset the states of a mem_cgroup
5357 * @css: the target css
5359 * Reset the states of the mem_cgroup associated with @css. This is
5360 * invoked when the userland requests disabling on the default hierarchy
5361 * but the memcg is pinned through dependency. The memcg should stop
5362 * applying policies and should revert to the vanilla state as it may be
5363 * made visible again.
5365 * The current implementation only resets the essential configurations.
5366 * This needs to be expanded to cover all the visible parts.
5368 static void mem_cgroup_css_reset(struct cgroup_subsys_state *css)
5370 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5372 page_counter_set_max(&memcg->memory, PAGE_COUNTER_MAX);
5373 page_counter_set_max(&memcg->swap, PAGE_COUNTER_MAX);
5374 page_counter_set_max(&memcg->kmem, PAGE_COUNTER_MAX);
5375 page_counter_set_max(&memcg->tcpmem, PAGE_COUNTER_MAX);
5376 page_counter_set_min(&memcg->memory, 0);
5377 page_counter_set_low(&memcg->memory, 0);
5378 page_counter_set_high(&memcg->memory, PAGE_COUNTER_MAX);
5379 memcg->soft_limit = PAGE_COUNTER_MAX;
5380 page_counter_set_high(&memcg->swap, PAGE_COUNTER_MAX);
5381 memcg_wb_domain_size_changed(memcg);
5384 static void mem_cgroup_css_rstat_flush(struct cgroup_subsys_state *css, int cpu)
5386 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5387 struct mem_cgroup *parent = parent_mem_cgroup(memcg);
5388 struct memcg_vmstats_percpu *statc;
5392 statc = per_cpu_ptr(memcg->vmstats_percpu, cpu);
5394 for (i = 0; i < MEMCG_NR_STAT; i++) {
5396 * Collect the aggregated propagation counts of groups
5397 * below us. We're in a per-cpu loop here and this is
5398 * a global counter, so the first cycle will get them.
5400 delta = memcg->vmstats.state_pending[i];
5402 memcg->vmstats.state_pending[i] = 0;
5404 /* Add CPU changes on this level since the last flush */
5405 v = READ_ONCE(statc->state[i]);
5406 if (v != statc->state_prev[i]) {
5407 delta += v - statc->state_prev[i];
5408 statc->state_prev[i] = v;
5414 /* Aggregate counts on this level and propagate upwards */
5415 memcg->vmstats.state[i] += delta;
5417 parent->vmstats.state_pending[i] += delta;
5420 for (i = 0; i < NR_VM_EVENT_ITEMS; i++) {
5421 delta = memcg->vmstats.events_pending[i];
5423 memcg->vmstats.events_pending[i] = 0;
5425 v = READ_ONCE(statc->events[i]);
5426 if (v != statc->events_prev[i]) {
5427 delta += v - statc->events_prev[i];
5428 statc->events_prev[i] = v;
5434 memcg->vmstats.events[i] += delta;
5436 parent->vmstats.events_pending[i] += delta;
5439 for_each_node_state(nid, N_MEMORY) {
5440 struct mem_cgroup_per_node *pn = memcg->nodeinfo[nid];
5441 struct mem_cgroup_per_node *ppn = NULL;
5442 struct lruvec_stats_percpu *lstatc;
5445 ppn = parent->nodeinfo[nid];
5447 lstatc = per_cpu_ptr(pn->lruvec_stats_percpu, cpu);
5449 for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) {
5450 delta = pn->lruvec_stats.state_pending[i];
5452 pn->lruvec_stats.state_pending[i] = 0;
5454 v = READ_ONCE(lstatc->state[i]);
5455 if (v != lstatc->state_prev[i]) {
5456 delta += v - lstatc->state_prev[i];
5457 lstatc->state_prev[i] = v;
5463 pn->lruvec_stats.state[i] += delta;
5465 ppn->lruvec_stats.state_pending[i] += delta;
5471 /* Handlers for move charge at task migration. */
5472 static int mem_cgroup_do_precharge(unsigned long count)
5476 /* Try a single bulk charge without reclaim first, kswapd may wake */
5477 ret = try_charge(mc.to, GFP_KERNEL & ~__GFP_DIRECT_RECLAIM, count);
5479 mc.precharge += count;
5483 /* Try charges one by one with reclaim, but do not retry */
5485 ret = try_charge(mc.to, GFP_KERNEL | __GFP_NORETRY, 1);
5499 enum mc_target_type {
5506 static struct page *mc_handle_present_pte(struct vm_area_struct *vma,
5507 unsigned long addr, pte_t ptent)
5509 struct page *page = vm_normal_page(vma, addr, ptent);
5511 if (!page || !page_mapped(page))
5513 if (PageAnon(page)) {
5514 if (!(mc.flags & MOVE_ANON))
5517 if (!(mc.flags & MOVE_FILE))
5520 if (!get_page_unless_zero(page))
5526 #if defined(CONFIG_SWAP) || defined(CONFIG_DEVICE_PRIVATE)
5527 static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
5528 pte_t ptent, swp_entry_t *entry)
5530 struct page *page = NULL;
5531 swp_entry_t ent = pte_to_swp_entry(ptent);
5533 if (!(mc.flags & MOVE_ANON))
5537 * Handle MEMORY_DEVICE_PRIVATE which are ZONE_DEVICE page belonging to
5538 * a device and because they are not accessible by CPU they are store
5539 * as special swap entry in the CPU page table.
5541 if (is_device_private_entry(ent)) {
5542 page = pfn_swap_entry_to_page(ent);
5544 * MEMORY_DEVICE_PRIVATE means ZONE_DEVICE page and which have
5545 * a refcount of 1 when free (unlike normal page)
5547 if (!page_ref_add_unless(page, 1, 1))
5552 if (non_swap_entry(ent))
5556 * Because lookup_swap_cache() updates some statistics counter,
5557 * we call find_get_page() with swapper_space directly.
5559 page = find_get_page(swap_address_space(ent), swp_offset(ent));
5560 entry->val = ent.val;
5565 static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
5566 pte_t ptent, swp_entry_t *entry)
5572 static struct page *mc_handle_file_pte(struct vm_area_struct *vma,
5573 unsigned long addr, pte_t ptent)
5575 if (!vma->vm_file) /* anonymous vma */
5577 if (!(mc.flags & MOVE_FILE))
5580 /* page is moved even if it's not RSS of this task(page-faulted). */
5581 /* shmem/tmpfs may report page out on swap: account for that too. */
5582 return find_get_incore_page(vma->vm_file->f_mapping,
5583 linear_page_index(vma, addr));
5587 * mem_cgroup_move_account - move account of the page
5589 * @compound: charge the page as compound or small page
5590 * @from: mem_cgroup which the page is moved from.
5591 * @to: mem_cgroup which the page is moved to. @from != @to.
5593 * The caller must make sure the page is not on LRU (isolate_page() is useful.)
5595 * This function doesn't do "charge" to new cgroup and doesn't do "uncharge"
5598 static int mem_cgroup_move_account(struct page *page,
5600 struct mem_cgroup *from,
5601 struct mem_cgroup *to)
5603 struct lruvec *from_vec, *to_vec;
5604 struct pglist_data *pgdat;
5605 unsigned int nr_pages = compound ? thp_nr_pages(page) : 1;
5608 VM_BUG_ON(from == to);
5609 VM_BUG_ON_PAGE(PageLRU(page), page);
5610 VM_BUG_ON(compound && !PageTransHuge(page));
5613 * Prevent mem_cgroup_migrate() from looking at
5614 * page's memory cgroup of its source page while we change it.
5617 if (!trylock_page(page))
5621 if (page_memcg(page) != from)
5624 pgdat = page_pgdat(page);
5625 from_vec = mem_cgroup_lruvec(from, pgdat);
5626 to_vec = mem_cgroup_lruvec(to, pgdat);
5628 lock_page_memcg(page);
5630 if (PageAnon(page)) {
5631 if (page_mapped(page)) {
5632 __mod_lruvec_state(from_vec, NR_ANON_MAPPED, -nr_pages);
5633 __mod_lruvec_state(to_vec, NR_ANON_MAPPED, nr_pages);
5634 if (PageTransHuge(page)) {
5635 __mod_lruvec_state(from_vec, NR_ANON_THPS,
5637 __mod_lruvec_state(to_vec, NR_ANON_THPS,
5642 __mod_lruvec_state(from_vec, NR_FILE_PAGES, -nr_pages);
5643 __mod_lruvec_state(to_vec, NR_FILE_PAGES, nr_pages);
5645 if (PageSwapBacked(page)) {
5646 __mod_lruvec_state(from_vec, NR_SHMEM, -nr_pages);
5647 __mod_lruvec_state(to_vec, NR_SHMEM, nr_pages);
5650 if (page_mapped(page)) {
5651 __mod_lruvec_state(from_vec, NR_FILE_MAPPED, -nr_pages);
5652 __mod_lruvec_state(to_vec, NR_FILE_MAPPED, nr_pages);
5655 if (PageDirty(page)) {
5656 struct address_space *mapping = page_mapping(page);
5658 if (mapping_can_writeback(mapping)) {
5659 __mod_lruvec_state(from_vec, NR_FILE_DIRTY,
5661 __mod_lruvec_state(to_vec, NR_FILE_DIRTY,
5667 if (PageWriteback(page)) {
5668 __mod_lruvec_state(from_vec, NR_WRITEBACK, -nr_pages);
5669 __mod_lruvec_state(to_vec, NR_WRITEBACK, nr_pages);
5673 * All state has been migrated, let's switch to the new memcg.
5675 * It is safe to change page's memcg here because the page
5676 * is referenced, charged, isolated, and locked: we can't race
5677 * with (un)charging, migration, LRU putback, or anything else
5678 * that would rely on a stable page's memory cgroup.
5680 * Note that lock_page_memcg is a memcg lock, not a page lock,
5681 * to save space. As soon as we switch page's memory cgroup to a
5682 * new memcg that isn't locked, the above state can change
5683 * concurrently again. Make sure we're truly done with it.
5688 css_put(&from->css);
5690 page->memcg_data = (unsigned long)to;
5692 __unlock_page_memcg(from);
5696 local_irq_disable();
5697 mem_cgroup_charge_statistics(to, page, nr_pages);
5698 memcg_check_events(to, page);
5699 mem_cgroup_charge_statistics(from, page, -nr_pages);
5700 memcg_check_events(from, page);
5709 * get_mctgt_type - get target type of moving charge
5710 * @vma: the vma the pte to be checked belongs
5711 * @addr: the address corresponding to the pte to be checked
5712 * @ptent: the pte to be checked
5713 * @target: the pointer the target page or swap ent will be stored(can be NULL)
5716 * 0(MC_TARGET_NONE): if the pte is not a target for move charge.
5717 * 1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for
5718 * move charge. if @target is not NULL, the page is stored in target->page
5719 * with extra refcnt got(Callers should handle it).
5720 * 2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a
5721 * target for charge migration. if @target is not NULL, the entry is stored
5723 * 3(MC_TARGET_DEVICE): like MC_TARGET_PAGE but page is MEMORY_DEVICE_PRIVATE
5724 * (so ZONE_DEVICE page and thus not on the lru).
5725 * For now we such page is charge like a regular page would be as for all
5726 * intent and purposes it is just special memory taking the place of a
5729 * See Documentations/vm/hmm.txt and include/linux/hmm.h
5731 * Called with pte lock held.
5734 static enum mc_target_type get_mctgt_type(struct vm_area_struct *vma,
5735 unsigned long addr, pte_t ptent, union mc_target *target)
5737 struct page *page = NULL;
5738 enum mc_target_type ret = MC_TARGET_NONE;
5739 swp_entry_t ent = { .val = 0 };
5741 if (pte_present(ptent))
5742 page = mc_handle_present_pte(vma, addr, ptent);
5743 else if (is_swap_pte(ptent))
5744 page = mc_handle_swap_pte(vma, ptent, &ent);
5745 else if (pte_none(ptent))
5746 page = mc_handle_file_pte(vma, addr, ptent);
5748 if (!page && !ent.val)
5752 * Do only loose check w/o serialization.
5753 * mem_cgroup_move_account() checks the page is valid or
5754 * not under LRU exclusion.
5756 if (page_memcg(page) == mc.from) {
5757 ret = MC_TARGET_PAGE;
5758 if (is_device_private_page(page))
5759 ret = MC_TARGET_DEVICE;
5761 target->page = page;
5763 if (!ret || !target)
5767 * There is a swap entry and a page doesn't exist or isn't charged.
5768 * But we cannot move a tail-page in a THP.
5770 if (ent.val && !ret && (!page || !PageTransCompound(page)) &&
5771 mem_cgroup_id(mc.from) == lookup_swap_cgroup_id(ent)) {
5772 ret = MC_TARGET_SWAP;
5779 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
5781 * We don't consider PMD mapped swapping or file mapped pages because THP does
5782 * not support them for now.
5783 * Caller should make sure that pmd_trans_huge(pmd) is true.
5785 static enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma,
5786 unsigned long addr, pmd_t pmd, union mc_target *target)
5788 struct page *page = NULL;
5789 enum mc_target_type ret = MC_TARGET_NONE;
5791 if (unlikely(is_swap_pmd(pmd))) {
5792 VM_BUG_ON(thp_migration_supported() &&
5793 !is_pmd_migration_entry(pmd));
5796 page = pmd_page(pmd);
5797 VM_BUG_ON_PAGE(!page || !PageHead(page), page);
5798 if (!(mc.flags & MOVE_ANON))
5800 if (page_memcg(page) == mc.from) {
5801 ret = MC_TARGET_PAGE;
5804 target->page = page;
5810 static inline enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma,
5811 unsigned long addr, pmd_t pmd, union mc_target *target)
5813 return MC_TARGET_NONE;
5817 static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd,
5818 unsigned long addr, unsigned long end,
5819 struct mm_walk *walk)
5821 struct vm_area_struct *vma = walk->vma;
5825 ptl = pmd_trans_huge_lock(pmd, vma);
5828 * Note their can not be MC_TARGET_DEVICE for now as we do not
5829 * support transparent huge page with MEMORY_DEVICE_PRIVATE but
5830 * this might change.
5832 if (get_mctgt_type_thp(vma, addr, *pmd, NULL) == MC_TARGET_PAGE)
5833 mc.precharge += HPAGE_PMD_NR;
5838 if (pmd_trans_unstable(pmd))
5840 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
5841 for (; addr != end; pte++, addr += PAGE_SIZE)
5842 if (get_mctgt_type(vma, addr, *pte, NULL))
5843 mc.precharge++; /* increment precharge temporarily */
5844 pte_unmap_unlock(pte - 1, ptl);
5850 static const struct mm_walk_ops precharge_walk_ops = {
5851 .pmd_entry = mem_cgroup_count_precharge_pte_range,
5854 static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm)
5856 unsigned long precharge;
5859 walk_page_range(mm, 0, mm->highest_vm_end, &precharge_walk_ops, NULL);
5860 mmap_read_unlock(mm);
5862 precharge = mc.precharge;
5868 static int mem_cgroup_precharge_mc(struct mm_struct *mm)
5870 unsigned long precharge = mem_cgroup_count_precharge(mm);
5872 VM_BUG_ON(mc.moving_task);
5873 mc.moving_task = current;
5874 return mem_cgroup_do_precharge(precharge);
5877 /* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */
5878 static void __mem_cgroup_clear_mc(void)
5880 struct mem_cgroup *from = mc.from;
5881 struct mem_cgroup *to = mc.to;
5883 /* we must uncharge all the leftover precharges from mc.to */
5885 cancel_charge(mc.to, mc.precharge);
5889 * we didn't uncharge from mc.from at mem_cgroup_move_account(), so
5890 * we must uncharge here.
5892 if (mc.moved_charge) {
5893 cancel_charge(mc.from, mc.moved_charge);
5894 mc.moved_charge = 0;
5896 /* we must fixup refcnts and charges */
5897 if (mc.moved_swap) {
5898 /* uncharge swap account from the old cgroup */
5899 if (!mem_cgroup_is_root(mc.from))
5900 page_counter_uncharge(&mc.from->memsw, mc.moved_swap);
5902 mem_cgroup_id_put_many(mc.from, mc.moved_swap);
5905 * we charged both to->memory and to->memsw, so we
5906 * should uncharge to->memory.
5908 if (!mem_cgroup_is_root(mc.to))
5909 page_counter_uncharge(&mc.to->memory, mc.moved_swap);
5913 memcg_oom_recover(from);
5914 memcg_oom_recover(to);
5915 wake_up_all(&mc.waitq);
5918 static void mem_cgroup_clear_mc(void)
5920 struct mm_struct *mm = mc.mm;
5923 * we must clear moving_task before waking up waiters at the end of
5926 mc.moving_task = NULL;
5927 __mem_cgroup_clear_mc();
5928 spin_lock(&mc.lock);
5932 spin_unlock(&mc.lock);
5937 static int mem_cgroup_can_attach(struct cgroup_taskset *tset)
5939 struct cgroup_subsys_state *css;
5940 struct mem_cgroup *memcg = NULL; /* unneeded init to make gcc happy */
5941 struct mem_cgroup *from;
5942 struct task_struct *leader, *p;
5943 struct mm_struct *mm;
5944 unsigned long move_flags;
5947 /* charge immigration isn't supported on the default hierarchy */
5948 if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
5952 * Multi-process migrations only happen on the default hierarchy
5953 * where charge immigration is not used. Perform charge
5954 * immigration if @tset contains a leader and whine if there are
5958 cgroup_taskset_for_each_leader(leader, css, tset) {
5961 memcg = mem_cgroup_from_css(css);
5967 * We are now committed to this value whatever it is. Changes in this
5968 * tunable will only affect upcoming migrations, not the current one.
5969 * So we need to save it, and keep it going.
5971 move_flags = READ_ONCE(memcg->move_charge_at_immigrate);
5975 from = mem_cgroup_from_task(p);
5977 VM_BUG_ON(from == memcg);
5979 mm = get_task_mm(p);
5982 /* We move charges only when we move a owner of the mm */
5983 if (mm->owner == p) {
5986 VM_BUG_ON(mc.precharge);
5987 VM_BUG_ON(mc.moved_charge);
5988 VM_BUG_ON(mc.moved_swap);
5990 spin_lock(&mc.lock);
5994 mc.flags = move_flags;
5995 spin_unlock(&mc.lock);
5996 /* We set mc.moving_task later */
5998 ret = mem_cgroup_precharge_mc(mm);
6000 mem_cgroup_clear_mc();
6007 static void mem_cgroup_cancel_attach(struct cgroup_taskset *tset)
6010 mem_cgroup_clear_mc();
6013 static int mem_cgroup_move_charge_pte_range(pmd_t *pmd,
6014 unsigned long addr, unsigned long end,
6015 struct mm_walk *walk)
6018 struct vm_area_struct *vma = walk->vma;
6021 enum mc_target_type target_type;
6022 union mc_target target;
6025 ptl = pmd_trans_huge_lock(pmd, vma);
6027 if (mc.precharge < HPAGE_PMD_NR) {
6031 target_type = get_mctgt_type_thp(vma, addr, *pmd, &target);
6032 if (target_type == MC_TARGET_PAGE) {
6034 if (!isolate_lru_page(page)) {
6035 if (!mem_cgroup_move_account(page, true,
6037 mc.precharge -= HPAGE_PMD_NR;
6038 mc.moved_charge += HPAGE_PMD_NR;
6040 putback_lru_page(page);
6043 } else if (target_type == MC_TARGET_DEVICE) {
6045 if (!mem_cgroup_move_account(page, true,
6047 mc.precharge -= HPAGE_PMD_NR;
6048 mc.moved_charge += HPAGE_PMD_NR;
6056 if (pmd_trans_unstable(pmd))
6059 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
6060 for (; addr != end; addr += PAGE_SIZE) {
6061 pte_t ptent = *(pte++);
6062 bool device = false;
6068 switch (get_mctgt_type(vma, addr, ptent, &target)) {
6069 case MC_TARGET_DEVICE:
6072 case MC_TARGET_PAGE:
6075 * We can have a part of the split pmd here. Moving it
6076 * can be done but it would be too convoluted so simply
6077 * ignore such a partial THP and keep it in original
6078 * memcg. There should be somebody mapping the head.
6080 if (PageTransCompound(page))
6082 if (!device && isolate_lru_page(page))
6084 if (!mem_cgroup_move_account(page, false,
6087 /* we uncharge from mc.from later. */
6091 putback_lru_page(page);
6092 put: /* get_mctgt_type() gets the page */
6095 case MC_TARGET_SWAP:
6097 if (!mem_cgroup_move_swap_account(ent, mc.from, mc.to)) {
6099 mem_cgroup_id_get_many(mc.to, 1);
6100 /* we fixup other refcnts and charges later. */
6108 pte_unmap_unlock(pte - 1, ptl);
6113 * We have consumed all precharges we got in can_attach().
6114 * We try charge one by one, but don't do any additional
6115 * charges to mc.to if we have failed in charge once in attach()
6118 ret = mem_cgroup_do_precharge(1);
6126 static const struct mm_walk_ops charge_walk_ops = {
6127 .pmd_entry = mem_cgroup_move_charge_pte_range,
6130 static void mem_cgroup_move_charge(void)
6132 lru_add_drain_all();
6134 * Signal lock_page_memcg() to take the memcg's move_lock
6135 * while we're moving its pages to another memcg. Then wait
6136 * for already started RCU-only updates to finish.
6138 atomic_inc(&mc.from->moving_account);
6141 if (unlikely(!mmap_read_trylock(mc.mm))) {
6143 * Someone who are holding the mmap_lock might be waiting in
6144 * waitq. So we cancel all extra charges, wake up all waiters,
6145 * and retry. Because we cancel precharges, we might not be able
6146 * to move enough charges, but moving charge is a best-effort
6147 * feature anyway, so it wouldn't be a big problem.
6149 __mem_cgroup_clear_mc();
6154 * When we have consumed all precharges and failed in doing
6155 * additional charge, the page walk just aborts.
6157 walk_page_range(mc.mm, 0, mc.mm->highest_vm_end, &charge_walk_ops,
6160 mmap_read_unlock(mc.mm);
6161 atomic_dec(&mc.from->moving_account);
6164 static void mem_cgroup_move_task(void)
6167 mem_cgroup_move_charge();
6168 mem_cgroup_clear_mc();
6171 #else /* !CONFIG_MMU */
6172 static int mem_cgroup_can_attach(struct cgroup_taskset *tset)
6176 static void mem_cgroup_cancel_attach(struct cgroup_taskset *tset)
6179 static void mem_cgroup_move_task(void)
6184 static int seq_puts_memcg_tunable(struct seq_file *m, unsigned long value)
6186 if (value == PAGE_COUNTER_MAX)
6187 seq_puts(m, "max\n");
6189 seq_printf(m, "%llu\n", (u64)value * PAGE_SIZE);
6194 static u64 memory_current_read(struct cgroup_subsys_state *css,
6197 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
6199 return (u64)page_counter_read(&memcg->memory) * PAGE_SIZE;
6202 static int memory_min_show(struct seq_file *m, void *v)
6204 return seq_puts_memcg_tunable(m,
6205 READ_ONCE(mem_cgroup_from_seq(m)->memory.min));
6208 static ssize_t memory_min_write(struct kernfs_open_file *of,
6209 char *buf, size_t nbytes, loff_t off)
6211 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
6215 buf = strstrip(buf);
6216 err = page_counter_memparse(buf, "max", &min);
6220 page_counter_set_min(&memcg->memory, min);
6225 static int memory_low_show(struct seq_file *m, void *v)
6227 return seq_puts_memcg_tunable(m,
6228 READ_ONCE(mem_cgroup_from_seq(m)->memory.low));
6231 static ssize_t memory_low_write(struct kernfs_open_file *of,
6232 char *buf, size_t nbytes, loff_t off)
6234 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
6238 buf = strstrip(buf);
6239 err = page_counter_memparse(buf, "max", &low);
6243 page_counter_set_low(&memcg->memory, low);
6248 static int memory_high_show(struct seq_file *m, void *v)
6250 return seq_puts_memcg_tunable(m,
6251 READ_ONCE(mem_cgroup_from_seq(m)->memory.high));
6254 static ssize_t memory_high_write(struct kernfs_open_file *of,
6255 char *buf, size_t nbytes, loff_t off)
6257 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
6258 unsigned int nr_retries = MAX_RECLAIM_RETRIES;
6259 bool drained = false;
6263 buf = strstrip(buf);
6264 err = page_counter_memparse(buf, "max", &high);
6268 page_counter_set_high(&memcg->memory, high);
6271 unsigned long nr_pages = page_counter_read(&memcg->memory);
6272 unsigned long reclaimed;
6274 if (nr_pages <= high)
6277 if (signal_pending(current))
6281 drain_all_stock(memcg);
6286 reclaimed = try_to_free_mem_cgroup_pages(memcg, nr_pages - high,
6289 if (!reclaimed && !nr_retries--)
6293 memcg_wb_domain_size_changed(memcg);
6297 static int memory_max_show(struct seq_file *m, void *v)
6299 return seq_puts_memcg_tunable(m,
6300 READ_ONCE(mem_cgroup_from_seq(m)->memory.max));
6303 static ssize_t memory_max_write(struct kernfs_open_file *of,
6304 char *buf, size_t nbytes, loff_t off)
6306 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
6307 unsigned int nr_reclaims = MAX_RECLAIM_RETRIES;
6308 bool drained = false;
6312 buf = strstrip(buf);
6313 err = page_counter_memparse(buf, "max", &max);
6317 xchg(&memcg->memory.max, max);
6320 unsigned long nr_pages = page_counter_read(&memcg->memory);
6322 if (nr_pages <= max)
6325 if (signal_pending(current))
6329 drain_all_stock(memcg);
6335 if (!try_to_free_mem_cgroup_pages(memcg, nr_pages - max,
6341 memcg_memory_event(memcg, MEMCG_OOM);
6342 if (!mem_cgroup_out_of_memory(memcg, GFP_KERNEL, 0))
6346 memcg_wb_domain_size_changed(memcg);
6350 static void __memory_events_show(struct seq_file *m, atomic_long_t *events)
6352 seq_printf(m, "low %lu\n", atomic_long_read(&events[MEMCG_LOW]));
6353 seq_printf(m, "high %lu\n", atomic_long_read(&events[MEMCG_HIGH]));
6354 seq_printf(m, "max %lu\n", atomic_long_read(&events[MEMCG_MAX]));
6355 seq_printf(m, "oom %lu\n", atomic_long_read(&events[MEMCG_OOM]));
6356 seq_printf(m, "oom_kill %lu\n",
6357 atomic_long_read(&events[MEMCG_OOM_KILL]));
6360 static int memory_events_show(struct seq_file *m, void *v)
6362 struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
6364 __memory_events_show(m, memcg->memory_events);
6368 static int memory_events_local_show(struct seq_file *m, void *v)
6370 struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
6372 __memory_events_show(m, memcg->memory_events_local);
6376 static int memory_stat_show(struct seq_file *m, void *v)
6378 struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
6381 buf = memory_stat_format(memcg);
6390 static inline unsigned long lruvec_page_state_output(struct lruvec *lruvec,
6393 return lruvec_page_state(lruvec, item) * memcg_page_state_unit(item);
6396 static int memory_numa_stat_show(struct seq_file *m, void *v)
6399 struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
6401 mem_cgroup_flush_stats();
6403 for (i = 0; i < ARRAY_SIZE(memory_stats); i++) {
6406 if (memory_stats[i].idx >= NR_VM_NODE_STAT_ITEMS)
6409 seq_printf(m, "%s", memory_stats[i].name);
6410 for_each_node_state(nid, N_MEMORY) {
6412 struct lruvec *lruvec;
6414 lruvec = mem_cgroup_lruvec(memcg, NODE_DATA(nid));
6415 size = lruvec_page_state_output(lruvec,
6416 memory_stats[i].idx);
6417 seq_printf(m, " N%d=%llu", nid, size);
6426 static int memory_oom_group_show(struct seq_file *m, void *v)
6428 struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
6430 seq_printf(m, "%d\n", memcg->oom_group);
6435 static ssize_t memory_oom_group_write(struct kernfs_open_file *of,
6436 char *buf, size_t nbytes, loff_t off)
6438 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
6441 buf = strstrip(buf);
6445 ret = kstrtoint(buf, 0, &oom_group);
6449 if (oom_group != 0 && oom_group != 1)
6452 memcg->oom_group = oom_group;
6457 static struct cftype memory_files[] = {
6460 .flags = CFTYPE_NOT_ON_ROOT,
6461 .read_u64 = memory_current_read,
6465 .flags = CFTYPE_NOT_ON_ROOT,
6466 .seq_show = memory_min_show,
6467 .write = memory_min_write,
6471 .flags = CFTYPE_NOT_ON_ROOT,
6472 .seq_show = memory_low_show,
6473 .write = memory_low_write,
6477 .flags = CFTYPE_NOT_ON_ROOT,
6478 .seq_show = memory_high_show,
6479 .write = memory_high_write,
6483 .flags = CFTYPE_NOT_ON_ROOT,
6484 .seq_show = memory_max_show,
6485 .write = memory_max_write,
6489 .flags = CFTYPE_NOT_ON_ROOT,
6490 .file_offset = offsetof(struct mem_cgroup, events_file),
6491 .seq_show = memory_events_show,
6494 .name = "events.local",
6495 .flags = CFTYPE_NOT_ON_ROOT,
6496 .file_offset = offsetof(struct mem_cgroup, events_local_file),
6497 .seq_show = memory_events_local_show,
6501 .seq_show = memory_stat_show,
6505 .name = "numa_stat",
6506 .seq_show = memory_numa_stat_show,
6510 .name = "oom.group",
6511 .flags = CFTYPE_NOT_ON_ROOT | CFTYPE_NS_DELEGATABLE,
6512 .seq_show = memory_oom_group_show,
6513 .write = memory_oom_group_write,
6518 struct cgroup_subsys memory_cgrp_subsys = {
6519 .css_alloc = mem_cgroup_css_alloc,
6520 .css_online = mem_cgroup_css_online,
6521 .css_offline = mem_cgroup_css_offline,
6522 .css_released = mem_cgroup_css_released,
6523 .css_free = mem_cgroup_css_free,
6524 .css_reset = mem_cgroup_css_reset,
6525 .css_rstat_flush = mem_cgroup_css_rstat_flush,
6526 .can_attach = mem_cgroup_can_attach,
6527 .cancel_attach = mem_cgroup_cancel_attach,
6528 .post_attach = mem_cgroup_move_task,
6529 .dfl_cftypes = memory_files,
6530 .legacy_cftypes = mem_cgroup_legacy_files,
6535 * This function calculates an individual cgroup's effective
6536 * protection which is derived from its own memory.min/low, its
6537 * parent's and siblings' settings, as well as the actual memory
6538 * distribution in the tree.
6540 * The following rules apply to the effective protection values:
6542 * 1. At the first level of reclaim, effective protection is equal to
6543 * the declared protection in memory.min and memory.low.
6545 * 2. To enable safe delegation of the protection configuration, at
6546 * subsequent levels the effective protection is capped to the
6547 * parent's effective protection.
6549 * 3. To make complex and dynamic subtrees easier to configure, the
6550 * user is allowed to overcommit the declared protection at a given
6551 * level. If that is the case, the parent's effective protection is
6552 * distributed to the children in proportion to how much protection
6553 * they have declared and how much of it they are utilizing.
6555 * This makes distribution proportional, but also work-conserving:
6556 * if one cgroup claims much more protection than it uses memory,
6557 * the unused remainder is available to its siblings.
6559 * 4. Conversely, when the declared protection is undercommitted at a
6560 * given level, the distribution of the larger parental protection
6561 * budget is NOT proportional. A cgroup's protection from a sibling
6562 * is capped to its own memory.min/low setting.
6564 * 5. However, to allow protecting recursive subtrees from each other
6565 * without having to declare each individual cgroup's fixed share
6566 * of the ancestor's claim to protection, any unutilized -
6567 * "floating" - protection from up the tree is distributed in
6568 * proportion to each cgroup's *usage*. This makes the protection
6569 * neutral wrt sibling cgroups and lets them compete freely over
6570 * the shared parental protection budget, but it protects the
6571 * subtree as a whole from neighboring subtrees.
6573 * Note that 4. and 5. are not in conflict: 4. is about protecting
6574 * against immediate siblings whereas 5. is about protecting against
6575 * neighboring subtrees.
6577 static unsigned long effective_protection(unsigned long usage,
6578 unsigned long parent_usage,
6579 unsigned long setting,
6580 unsigned long parent_effective,
6581 unsigned long siblings_protected)
6583 unsigned long protected;
6586 protected = min(usage, setting);
6588 * If all cgroups at this level combined claim and use more
6589 * protection then what the parent affords them, distribute
6590 * shares in proportion to utilization.
6592 * We are using actual utilization rather than the statically
6593 * claimed protection in order to be work-conserving: claimed
6594 * but unused protection is available to siblings that would
6595 * otherwise get a smaller chunk than what they claimed.
6597 if (siblings_protected > parent_effective)
6598 return protected * parent_effective / siblings_protected;
6601 * Ok, utilized protection of all children is within what the
6602 * parent affords them, so we know whatever this child claims
6603 * and utilizes is effectively protected.
6605 * If there is unprotected usage beyond this value, reclaim
6606 * will apply pressure in proportion to that amount.
6608 * If there is unutilized protection, the cgroup will be fully
6609 * shielded from reclaim, but we do return a smaller value for
6610 * protection than what the group could enjoy in theory. This
6611 * is okay. With the overcommit distribution above, effective
6612 * protection is always dependent on how memory is actually
6613 * consumed among the siblings anyway.
6618 * If the children aren't claiming (all of) the protection
6619 * afforded to them by the parent, distribute the remainder in
6620 * proportion to the (unprotected) memory of each cgroup. That
6621 * way, cgroups that aren't explicitly prioritized wrt each
6622 * other compete freely over the allowance, but they are
6623 * collectively protected from neighboring trees.
6625 * We're using unprotected memory for the weight so that if
6626 * some cgroups DO claim explicit protection, we don't protect
6627 * the same bytes twice.
6629 * Check both usage and parent_usage against the respective
6630 * protected values. One should imply the other, but they
6631 * aren't read atomically - make sure the division is sane.
6633 if (!(cgrp_dfl_root.flags & CGRP_ROOT_MEMORY_RECURSIVE_PROT))
6635 if (parent_effective > siblings_protected &&
6636 parent_usage > siblings_protected &&
6637 usage > protected) {
6638 unsigned long unclaimed;
6640 unclaimed = parent_effective - siblings_protected;
6641 unclaimed *= usage - protected;
6642 unclaimed /= parent_usage - siblings_protected;
6651 * mem_cgroup_calculate_protection - check if memory consumption is in the normal range
6652 * @root: the top ancestor of the sub-tree being checked
6653 * @memcg: the memory cgroup to check
6655 * WARNING: This function is not stateless! It can only be used as part
6656 * of a top-down tree iteration, not for isolated queries.
6658 void mem_cgroup_calculate_protection(struct mem_cgroup *root,
6659 struct mem_cgroup *memcg)
6661 unsigned long usage, parent_usage;
6662 struct mem_cgroup *parent;
6664 if (mem_cgroup_disabled())
6668 root = root_mem_cgroup;
6671 * Effective values of the reclaim targets are ignored so they
6672 * can be stale. Have a look at mem_cgroup_protection for more
6674 * TODO: calculation should be more robust so that we do not need
6675 * that special casing.
6680 usage = page_counter_read(&memcg->memory);
6684 parent = parent_mem_cgroup(memcg);
6685 /* No parent means a non-hierarchical mode on v1 memcg */
6689 if (parent == root) {
6690 memcg->memory.emin = READ_ONCE(memcg->memory.min);
6691 memcg->memory.elow = READ_ONCE(memcg->memory.low);
6695 parent_usage = page_counter_read(&parent->memory);
6697 WRITE_ONCE(memcg->memory.emin, effective_protection(usage, parent_usage,
6698 READ_ONCE(memcg->memory.min),
6699 READ_ONCE(parent->memory.emin),
6700 atomic_long_read(&parent->memory.children_min_usage)));
6702 WRITE_ONCE(memcg->memory.elow, effective_protection(usage, parent_usage,
6703 READ_ONCE(memcg->memory.low),
6704 READ_ONCE(parent->memory.elow),
6705 atomic_long_read(&parent->memory.children_low_usage)));
6708 static int charge_memcg(struct page *page, struct mem_cgroup *memcg, gfp_t gfp)
6710 unsigned int nr_pages = thp_nr_pages(page);
6713 ret = try_charge(memcg, gfp, nr_pages);
6717 css_get(&memcg->css);
6718 commit_charge(page, memcg);
6720 local_irq_disable();
6721 mem_cgroup_charge_statistics(memcg, page, nr_pages);
6722 memcg_check_events(memcg, page);
6729 * __mem_cgroup_charge - charge a newly allocated page to a cgroup
6730 * @page: page to charge
6731 * @mm: mm context of the victim
6732 * @gfp_mask: reclaim mode
6734 * Try to charge @page to the memcg that @mm belongs to, reclaiming
6735 * pages according to @gfp_mask if necessary. if @mm is NULL, try to
6736 * charge to the active memcg.
6738 * Do not use this for pages allocated for swapin.
6740 * Returns 0 on success. Otherwise, an error code is returned.
6742 int __mem_cgroup_charge(struct page *page, struct mm_struct *mm,
6745 struct mem_cgroup *memcg;
6748 memcg = get_mem_cgroup_from_mm(mm);
6749 ret = charge_memcg(page, memcg, gfp_mask);
6750 css_put(&memcg->css);
6756 * mem_cgroup_swapin_charge_page - charge a newly allocated page for swapin
6757 * @page: page to charge
6758 * @mm: mm context of the victim
6759 * @gfp: reclaim mode
6760 * @entry: swap entry for which the page is allocated
6762 * This function charges a page allocated for swapin. Please call this before
6763 * adding the page to the swapcache.
6765 * Returns 0 on success. Otherwise, an error code is returned.
6767 int mem_cgroup_swapin_charge_page(struct page *page, struct mm_struct *mm,
6768 gfp_t gfp, swp_entry_t entry)
6770 struct mem_cgroup *memcg;
6774 if (mem_cgroup_disabled())
6777 id = lookup_swap_cgroup_id(entry);
6779 memcg = mem_cgroup_from_id(id);
6780 if (!memcg || !css_tryget_online(&memcg->css))
6781 memcg = get_mem_cgroup_from_mm(mm);
6784 ret = charge_memcg(page, memcg, gfp);
6786 css_put(&memcg->css);
6791 * mem_cgroup_swapin_uncharge_swap - uncharge swap slot
6792 * @entry: swap entry for which the page is charged
6794 * Call this function after successfully adding the charged page to swapcache.
6796 * Note: This function assumes the page for which swap slot is being uncharged
6799 void mem_cgroup_swapin_uncharge_swap(swp_entry_t entry)
6802 * Cgroup1's unified memory+swap counter has been charged with the
6803 * new swapcache page, finish the transfer by uncharging the swap
6804 * slot. The swap slot would also get uncharged when it dies, but
6805 * it can stick around indefinitely and we'd count the page twice
6808 * Cgroup2 has separate resource counters for memory and swap,
6809 * so this is a non-issue here. Memory and swap charge lifetimes
6810 * correspond 1:1 to page and swap slot lifetimes: we charge the
6811 * page to memory here, and uncharge swap when the slot is freed.
6813 if (!mem_cgroup_disabled() && do_memsw_account()) {
6815 * The swap entry might not get freed for a long time,
6816 * let's not wait for it. The page already received a
6817 * memory+swap charge, drop the swap entry duplicate.
6819 mem_cgroup_uncharge_swap(entry, 1);
6823 struct uncharge_gather {
6824 struct mem_cgroup *memcg;
6825 unsigned long nr_memory;
6826 unsigned long pgpgout;
6827 unsigned long nr_kmem;
6828 struct page *dummy_page;
6831 static inline void uncharge_gather_clear(struct uncharge_gather *ug)
6833 memset(ug, 0, sizeof(*ug));
6836 static void uncharge_batch(const struct uncharge_gather *ug)
6838 unsigned long flags;
6840 if (ug->nr_memory) {
6841 page_counter_uncharge(&ug->memcg->memory, ug->nr_memory);
6842 if (do_memsw_account())
6843 page_counter_uncharge(&ug->memcg->memsw, ug->nr_memory);
6844 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && ug->nr_kmem)
6845 page_counter_uncharge(&ug->memcg->kmem, ug->nr_kmem);
6846 memcg_oom_recover(ug->memcg);
6849 local_irq_save(flags);
6850 __count_memcg_events(ug->memcg, PGPGOUT, ug->pgpgout);
6851 __this_cpu_add(ug->memcg->vmstats_percpu->nr_page_events, ug->nr_memory);
6852 memcg_check_events(ug->memcg, ug->dummy_page);
6853 local_irq_restore(flags);
6855 /* drop reference from uncharge_page */
6856 css_put(&ug->memcg->css);
6859 static void uncharge_page(struct page *page, struct uncharge_gather *ug)
6861 unsigned long nr_pages;
6862 struct mem_cgroup *memcg;
6863 struct obj_cgroup *objcg;
6864 bool use_objcg = PageMemcgKmem(page);
6866 VM_BUG_ON_PAGE(PageLRU(page), page);
6869 * Nobody should be changing or seriously looking at
6870 * page memcg or objcg at this point, we have fully
6871 * exclusive access to the page.
6874 objcg = __page_objcg(page);
6876 * This get matches the put at the end of the function and
6877 * kmem pages do not hold memcg references anymore.
6879 memcg = get_mem_cgroup_from_objcg(objcg);
6881 memcg = __page_memcg(page);
6887 if (ug->memcg != memcg) {
6890 uncharge_gather_clear(ug);
6893 ug->dummy_page = page;
6895 /* pairs with css_put in uncharge_batch */
6896 css_get(&memcg->css);
6899 nr_pages = compound_nr(page);
6902 ug->nr_memory += nr_pages;
6903 ug->nr_kmem += nr_pages;
6905 page->memcg_data = 0;
6906 obj_cgroup_put(objcg);
6908 /* LRU pages aren't accounted at the root level */
6909 if (!mem_cgroup_is_root(memcg))
6910 ug->nr_memory += nr_pages;
6913 page->memcg_data = 0;
6916 css_put(&memcg->css);
6920 * __mem_cgroup_uncharge - uncharge a page
6921 * @page: page to uncharge
6923 * Uncharge a page previously charged with __mem_cgroup_charge().
6925 void __mem_cgroup_uncharge(struct page *page)
6927 struct uncharge_gather ug;
6929 /* Don't touch page->lru of any random page, pre-check: */
6930 if (!page_memcg(page))
6933 uncharge_gather_clear(&ug);
6934 uncharge_page(page, &ug);
6935 uncharge_batch(&ug);
6939 * __mem_cgroup_uncharge_list - uncharge a list of page
6940 * @page_list: list of pages to uncharge
6942 * Uncharge a list of pages previously charged with
6943 * __mem_cgroup_charge().
6945 void __mem_cgroup_uncharge_list(struct list_head *page_list)
6947 struct uncharge_gather ug;
6950 uncharge_gather_clear(&ug);
6951 list_for_each_entry(page, page_list, lru)
6952 uncharge_page(page, &ug);
6954 uncharge_batch(&ug);
6958 * mem_cgroup_migrate - charge a page's replacement
6959 * @oldpage: currently circulating page
6960 * @newpage: replacement page
6962 * Charge @newpage as a replacement page for @oldpage. @oldpage will
6963 * be uncharged upon free.
6965 * Both pages must be locked, @newpage->mapping must be set up.
6967 void mem_cgroup_migrate(struct page *oldpage, struct page *newpage)
6969 struct mem_cgroup *memcg;
6970 unsigned int nr_pages;
6971 unsigned long flags;
6973 VM_BUG_ON_PAGE(!PageLocked(oldpage), oldpage);
6974 VM_BUG_ON_PAGE(!PageLocked(newpage), newpage);
6975 VM_BUG_ON_PAGE(PageAnon(oldpage) != PageAnon(newpage), newpage);
6976 VM_BUG_ON_PAGE(PageTransHuge(oldpage) != PageTransHuge(newpage),
6979 if (mem_cgroup_disabled())
6982 /* Page cache replacement: new page already charged? */
6983 if (page_memcg(newpage))
6986 memcg = page_memcg(oldpage);
6987 VM_WARN_ON_ONCE_PAGE(!memcg, oldpage);
6991 /* Force-charge the new page. The old one will be freed soon */
6992 nr_pages = thp_nr_pages(newpage);
6994 if (!mem_cgroup_is_root(memcg)) {
6995 page_counter_charge(&memcg->memory, nr_pages);
6996 if (do_memsw_account())
6997 page_counter_charge(&memcg->memsw, nr_pages);
7000 css_get(&memcg->css);
7001 commit_charge(newpage, memcg);
7003 local_irq_save(flags);
7004 mem_cgroup_charge_statistics(memcg, newpage, nr_pages);
7005 memcg_check_events(memcg, newpage);
7006 local_irq_restore(flags);
7009 DEFINE_STATIC_KEY_FALSE(memcg_sockets_enabled_key);
7010 EXPORT_SYMBOL(memcg_sockets_enabled_key);
7012 void mem_cgroup_sk_alloc(struct sock *sk)
7014 struct mem_cgroup *memcg;
7016 if (!mem_cgroup_sockets_enabled)
7019 /* Do not associate the sock with unrelated interrupted task's memcg. */
7024 memcg = mem_cgroup_from_task(current);
7025 if (memcg == root_mem_cgroup)
7027 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && !memcg->tcpmem_active)
7029 if (css_tryget(&memcg->css))
7030 sk->sk_memcg = memcg;
7035 void mem_cgroup_sk_free(struct sock *sk)
7038 css_put(&sk->sk_memcg->css);
7042 * mem_cgroup_charge_skmem - charge socket memory
7043 * @memcg: memcg to charge
7044 * @nr_pages: number of pages to charge
7045 * @gfp_mask: reclaim mode
7047 * Charges @nr_pages to @memcg. Returns %true if the charge fit within
7048 * @memcg's configured limit, %false if it doesn't.
7050 bool mem_cgroup_charge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages,
7053 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) {
7054 struct page_counter *fail;
7056 if (page_counter_try_charge(&memcg->tcpmem, nr_pages, &fail)) {
7057 memcg->tcpmem_pressure = 0;
7060 memcg->tcpmem_pressure = 1;
7061 if (gfp_mask & __GFP_NOFAIL) {
7062 page_counter_charge(&memcg->tcpmem, nr_pages);
7068 if (try_charge(memcg, gfp_mask, nr_pages) == 0) {
7069 mod_memcg_state(memcg, MEMCG_SOCK, nr_pages);
7077 * mem_cgroup_uncharge_skmem - uncharge socket memory
7078 * @memcg: memcg to uncharge
7079 * @nr_pages: number of pages to uncharge
7081 void mem_cgroup_uncharge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages)
7083 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) {
7084 page_counter_uncharge(&memcg->tcpmem, nr_pages);
7088 mod_memcg_state(memcg, MEMCG_SOCK, -nr_pages);
7090 refill_stock(memcg, nr_pages);
7093 static int __init cgroup_memory(char *s)
7097 while ((token = strsep(&s, ",")) != NULL) {
7100 if (!strcmp(token, "nosocket"))
7101 cgroup_memory_nosocket = true;
7102 if (!strcmp(token, "nokmem"))
7103 cgroup_memory_nokmem = true;
7107 __setup("cgroup.memory=", cgroup_memory);
7110 * subsys_initcall() for memory controller.
7112 * Some parts like memcg_hotplug_cpu_dead() have to be initialized from this
7113 * context because of lock dependencies (cgroup_lock -> cpu hotplug) but
7114 * basically everything that doesn't depend on a specific mem_cgroup structure
7115 * should be initialized from here.
7117 static int __init mem_cgroup_init(void)
7122 * Currently s32 type (can refer to struct batched_lruvec_stat) is
7123 * used for per-memcg-per-cpu caching of per-node statistics. In order
7124 * to work fine, we should make sure that the overfill threshold can't
7125 * exceed S32_MAX / PAGE_SIZE.
7127 BUILD_BUG_ON(MEMCG_CHARGE_BATCH > S32_MAX / PAGE_SIZE);
7129 cpuhp_setup_state_nocalls(CPUHP_MM_MEMCQ_DEAD, "mm/memctrl:dead", NULL,
7130 memcg_hotplug_cpu_dead);
7132 for_each_possible_cpu(cpu)
7133 INIT_WORK(&per_cpu_ptr(&memcg_stock, cpu)->work,
7136 for_each_node(node) {
7137 struct mem_cgroup_tree_per_node *rtpn;
7139 rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL,
7140 node_online(node) ? node : NUMA_NO_NODE);
7142 rtpn->rb_root = RB_ROOT;
7143 rtpn->rb_rightmost = NULL;
7144 spin_lock_init(&rtpn->lock);
7145 soft_limit_tree.rb_tree_per_node[node] = rtpn;
7150 subsys_initcall(mem_cgroup_init);
7152 #ifdef CONFIG_MEMCG_SWAP
7153 static struct mem_cgroup *mem_cgroup_id_get_online(struct mem_cgroup *memcg)
7155 while (!refcount_inc_not_zero(&memcg->id.ref)) {
7157 * The root cgroup cannot be destroyed, so it's refcount must
7160 if (WARN_ON_ONCE(memcg == root_mem_cgroup)) {
7164 memcg = parent_mem_cgroup(memcg);
7166 memcg = root_mem_cgroup;
7172 * mem_cgroup_swapout - transfer a memsw charge to swap
7173 * @page: page whose memsw charge to transfer
7174 * @entry: swap entry to move the charge to
7176 * Transfer the memsw charge of @page to @entry.
7178 void mem_cgroup_swapout(struct page *page, swp_entry_t entry)
7180 struct mem_cgroup *memcg, *swap_memcg;
7181 unsigned int nr_entries;
7182 unsigned short oldid;
7184 VM_BUG_ON_PAGE(PageLRU(page), page);
7185 VM_BUG_ON_PAGE(page_count(page), page);
7187 if (mem_cgroup_disabled())
7190 if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
7193 memcg = page_memcg(page);
7195 VM_WARN_ON_ONCE_PAGE(!memcg, page);
7200 * In case the memcg owning these pages has been offlined and doesn't
7201 * have an ID allocated to it anymore, charge the closest online
7202 * ancestor for the swap instead and transfer the memory+swap charge.
7204 swap_memcg = mem_cgroup_id_get_online(memcg);
7205 nr_entries = thp_nr_pages(page);
7206 /* Get references for the tail pages, too */
7208 mem_cgroup_id_get_many(swap_memcg, nr_entries - 1);
7209 oldid = swap_cgroup_record(entry, mem_cgroup_id(swap_memcg),
7211 VM_BUG_ON_PAGE(oldid, page);
7212 mod_memcg_state(swap_memcg, MEMCG_SWAP, nr_entries);
7214 page->memcg_data = 0;
7216 if (!mem_cgroup_is_root(memcg))
7217 page_counter_uncharge(&memcg->memory, nr_entries);
7219 if (!cgroup_memory_noswap && memcg != swap_memcg) {
7220 if (!mem_cgroup_is_root(swap_memcg))
7221 page_counter_charge(&swap_memcg->memsw, nr_entries);
7222 page_counter_uncharge(&memcg->memsw, nr_entries);
7226 * Interrupts should be disabled here because the caller holds the
7227 * i_pages lock which is taken with interrupts-off. It is
7228 * important here to have the interrupts disabled because it is the
7229 * only synchronisation we have for updating the per-CPU variables.
7231 VM_BUG_ON(!irqs_disabled());
7232 mem_cgroup_charge_statistics(memcg, page, -nr_entries);
7233 memcg_check_events(memcg, page);
7235 css_put(&memcg->css);
7239 * __mem_cgroup_try_charge_swap - try charging swap space for a page
7240 * @page: page being added to swap
7241 * @entry: swap entry to charge
7243 * Try to charge @page's memcg for the swap space at @entry.
7245 * Returns 0 on success, -ENOMEM on failure.
7247 int __mem_cgroup_try_charge_swap(struct page *page, swp_entry_t entry)
7249 unsigned int nr_pages = thp_nr_pages(page);
7250 struct page_counter *counter;
7251 struct mem_cgroup *memcg;
7252 unsigned short oldid;
7254 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys))
7257 memcg = page_memcg(page);
7259 VM_WARN_ON_ONCE_PAGE(!memcg, page);
7264 memcg_memory_event(memcg, MEMCG_SWAP_FAIL);
7268 memcg = mem_cgroup_id_get_online(memcg);
7270 if (!cgroup_memory_noswap && !mem_cgroup_is_root(memcg) &&
7271 !page_counter_try_charge(&memcg->swap, nr_pages, &counter)) {
7272 memcg_memory_event(memcg, MEMCG_SWAP_MAX);
7273 memcg_memory_event(memcg, MEMCG_SWAP_FAIL);
7274 mem_cgroup_id_put(memcg);
7278 /* Get references for the tail pages, too */
7280 mem_cgroup_id_get_many(memcg, nr_pages - 1);
7281 oldid = swap_cgroup_record(entry, mem_cgroup_id(memcg), nr_pages);
7282 VM_BUG_ON_PAGE(oldid, page);
7283 mod_memcg_state(memcg, MEMCG_SWAP, nr_pages);
7289 * __mem_cgroup_uncharge_swap - uncharge swap space
7290 * @entry: swap entry to uncharge
7291 * @nr_pages: the amount of swap space to uncharge
7293 void __mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages)
7295 struct mem_cgroup *memcg;
7298 id = swap_cgroup_record(entry, 0, nr_pages);
7300 memcg = mem_cgroup_from_id(id);
7302 if (!cgroup_memory_noswap && !mem_cgroup_is_root(memcg)) {
7303 if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
7304 page_counter_uncharge(&memcg->swap, nr_pages);
7306 page_counter_uncharge(&memcg->memsw, nr_pages);
7308 mod_memcg_state(memcg, MEMCG_SWAP, -nr_pages);
7309 mem_cgroup_id_put_many(memcg, nr_pages);
7314 long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg)
7316 long nr_swap_pages = get_nr_swap_pages();
7318 if (cgroup_memory_noswap || !cgroup_subsys_on_dfl(memory_cgrp_subsys))
7319 return nr_swap_pages;
7320 for (; memcg != root_mem_cgroup; memcg = parent_mem_cgroup(memcg))
7321 nr_swap_pages = min_t(long, nr_swap_pages,
7322 READ_ONCE(memcg->swap.max) -
7323 page_counter_read(&memcg->swap));
7324 return nr_swap_pages;
7327 bool mem_cgroup_swap_full(struct page *page)
7329 struct mem_cgroup *memcg;
7331 VM_BUG_ON_PAGE(!PageLocked(page), page);
7335 if (cgroup_memory_noswap || !cgroup_subsys_on_dfl(memory_cgrp_subsys))
7338 memcg = page_memcg(page);
7342 for (; memcg != root_mem_cgroup; memcg = parent_mem_cgroup(memcg)) {
7343 unsigned long usage = page_counter_read(&memcg->swap);
7345 if (usage * 2 >= READ_ONCE(memcg->swap.high) ||
7346 usage * 2 >= READ_ONCE(memcg->swap.max))
7353 static int __init setup_swap_account(char *s)
7355 if (!strcmp(s, "1"))
7356 cgroup_memory_noswap = false;
7357 else if (!strcmp(s, "0"))
7358 cgroup_memory_noswap = true;
7361 __setup("swapaccount=", setup_swap_account);
7363 static u64 swap_current_read(struct cgroup_subsys_state *css,
7366 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
7368 return (u64)page_counter_read(&memcg->swap) * PAGE_SIZE;
7371 static int swap_high_show(struct seq_file *m, void *v)
7373 return seq_puts_memcg_tunable(m,
7374 READ_ONCE(mem_cgroup_from_seq(m)->swap.high));
7377 static ssize_t swap_high_write(struct kernfs_open_file *of,
7378 char *buf, size_t nbytes, loff_t off)
7380 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
7384 buf = strstrip(buf);
7385 err = page_counter_memparse(buf, "max", &high);
7389 page_counter_set_high(&memcg->swap, high);
7394 static int swap_max_show(struct seq_file *m, void *v)
7396 return seq_puts_memcg_tunable(m,
7397 READ_ONCE(mem_cgroup_from_seq(m)->swap.max));
7400 static ssize_t swap_max_write(struct kernfs_open_file *of,
7401 char *buf, size_t nbytes, loff_t off)
7403 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
7407 buf = strstrip(buf);
7408 err = page_counter_memparse(buf, "max", &max);
7412 xchg(&memcg->swap.max, max);
7417 static int swap_events_show(struct seq_file *m, void *v)
7419 struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
7421 seq_printf(m, "high %lu\n",
7422 atomic_long_read(&memcg->memory_events[MEMCG_SWAP_HIGH]));
7423 seq_printf(m, "max %lu\n",
7424 atomic_long_read(&memcg->memory_events[MEMCG_SWAP_MAX]));
7425 seq_printf(m, "fail %lu\n",
7426 atomic_long_read(&memcg->memory_events[MEMCG_SWAP_FAIL]));
7431 static struct cftype swap_files[] = {
7433 .name = "swap.current",
7434 .flags = CFTYPE_NOT_ON_ROOT,
7435 .read_u64 = swap_current_read,
7438 .name = "swap.high",
7439 .flags = CFTYPE_NOT_ON_ROOT,
7440 .seq_show = swap_high_show,
7441 .write = swap_high_write,
7445 .flags = CFTYPE_NOT_ON_ROOT,
7446 .seq_show = swap_max_show,
7447 .write = swap_max_write,
7450 .name = "swap.events",
7451 .flags = CFTYPE_NOT_ON_ROOT,
7452 .file_offset = offsetof(struct mem_cgroup, swap_events_file),
7453 .seq_show = swap_events_show,
7458 static struct cftype memsw_files[] = {
7460 .name = "memsw.usage_in_bytes",
7461 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE),
7462 .read_u64 = mem_cgroup_read_u64,
7465 .name = "memsw.max_usage_in_bytes",
7466 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE),
7467 .write = mem_cgroup_reset,
7468 .read_u64 = mem_cgroup_read_u64,
7471 .name = "memsw.limit_in_bytes",
7472 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT),
7473 .write = mem_cgroup_write,
7474 .read_u64 = mem_cgroup_read_u64,
7477 .name = "memsw.failcnt",
7478 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT),
7479 .write = mem_cgroup_reset,
7480 .read_u64 = mem_cgroup_read_u64,
7482 { }, /* terminate */
7486 * If mem_cgroup_swap_init() is implemented as a subsys_initcall()
7487 * instead of a core_initcall(), this could mean cgroup_memory_noswap still
7488 * remains set to false even when memcg is disabled via "cgroup_disable=memory"
7489 * boot parameter. This may result in premature OOPS inside
7490 * mem_cgroup_get_nr_swap_pages() function in corner cases.
7492 static int __init mem_cgroup_swap_init(void)
7494 /* No memory control -> no swap control */
7495 if (mem_cgroup_disabled())
7496 cgroup_memory_noswap = true;
7498 if (cgroup_memory_noswap)
7501 WARN_ON(cgroup_add_dfl_cftypes(&memory_cgrp_subsys, swap_files));
7502 WARN_ON(cgroup_add_legacy_cftypes(&memory_cgrp_subsys, memsw_files));
7506 core_initcall(mem_cgroup_swap_init);
7508 #endif /* CONFIG_MEMCG_SWAP */