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 task_is_dying(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 static DEFINE_SPINLOCK(objcg_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(&objcg_lock, flags);
302 list_del(&objcg->list);
303 spin_unlock_irqrestore(&objcg_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(&objcg_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(&objcg_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);
653 static u64 flush_next_time;
655 #define FLUSH_TIME (2UL*HZ)
657 static inline void memcg_rstat_updated(struct mem_cgroup *memcg, int val)
661 cgroup_rstat_updated(memcg->css.cgroup, smp_processor_id());
663 x = __this_cpu_add_return(stats_updates, abs(val));
664 if (x > MEMCG_CHARGE_BATCH) {
665 atomic_add(x / MEMCG_CHARGE_BATCH, &stats_flush_threshold);
666 __this_cpu_write(stats_updates, 0);
670 static void __mem_cgroup_flush_stats(void)
674 if (!spin_trylock_irqsave(&stats_flush_lock, flag))
677 flush_next_time = jiffies_64 + 2*FLUSH_TIME;
678 cgroup_rstat_flush_irqsafe(root_mem_cgroup->css.cgroup);
679 atomic_set(&stats_flush_threshold, 0);
680 spin_unlock_irqrestore(&stats_flush_lock, flag);
683 void mem_cgroup_flush_stats(void)
685 if (atomic_read(&stats_flush_threshold) > num_online_cpus())
686 __mem_cgroup_flush_stats();
689 void mem_cgroup_flush_stats_delayed(void)
691 if (time_after64(jiffies_64, flush_next_time))
692 mem_cgroup_flush_stats();
695 static void flush_memcg_stats_dwork(struct work_struct *w)
697 __mem_cgroup_flush_stats();
698 queue_delayed_work(system_unbound_wq, &stats_flush_dwork, FLUSH_TIME);
702 * __mod_memcg_state - update cgroup memory statistics
703 * @memcg: the memory cgroup
704 * @idx: the stat item - can be enum memcg_stat_item or enum node_stat_item
705 * @val: delta to add to the counter, can be negative
707 void __mod_memcg_state(struct mem_cgroup *memcg, int idx, int val)
709 if (mem_cgroup_disabled())
712 __this_cpu_add(memcg->vmstats_percpu->state[idx], val);
713 memcg_rstat_updated(memcg, val);
716 /* idx can be of type enum memcg_stat_item or node_stat_item. */
717 static unsigned long memcg_page_state_local(struct mem_cgroup *memcg, int idx)
722 for_each_possible_cpu(cpu)
723 x += per_cpu(memcg->vmstats_percpu->state[idx], cpu);
731 void __mod_memcg_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx,
734 struct mem_cgroup_per_node *pn;
735 struct mem_cgroup *memcg;
737 pn = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
741 __this_cpu_add(memcg->vmstats_percpu->state[idx], val);
744 __this_cpu_add(pn->lruvec_stats_percpu->state[idx], val);
746 memcg_rstat_updated(memcg, val);
750 * __mod_lruvec_state - update lruvec memory statistics
751 * @lruvec: the lruvec
752 * @idx: the stat item
753 * @val: delta to add to the counter, can be negative
755 * The lruvec is the intersection of the NUMA node and a cgroup. This
756 * function updates the all three counters that are affected by a
757 * change of state at this level: per-node, per-cgroup, per-lruvec.
759 void __mod_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx,
763 __mod_node_page_state(lruvec_pgdat(lruvec), idx, val);
765 /* Update memcg and lruvec */
766 if (!mem_cgroup_disabled())
767 __mod_memcg_lruvec_state(lruvec, idx, val);
770 void __mod_lruvec_page_state(struct page *page, enum node_stat_item idx,
773 struct page *head = compound_head(page); /* rmap on tail pages */
774 struct mem_cgroup *memcg;
775 pg_data_t *pgdat = page_pgdat(page);
776 struct lruvec *lruvec;
779 memcg = page_memcg(head);
780 /* Untracked pages have no memcg, no lruvec. Update only the node */
783 __mod_node_page_state(pgdat, idx, val);
787 lruvec = mem_cgroup_lruvec(memcg, pgdat);
788 __mod_lruvec_state(lruvec, idx, val);
791 EXPORT_SYMBOL(__mod_lruvec_page_state);
793 void __mod_lruvec_kmem_state(void *p, enum node_stat_item idx, int val)
795 pg_data_t *pgdat = page_pgdat(virt_to_page(p));
796 struct mem_cgroup *memcg;
797 struct lruvec *lruvec;
800 memcg = mem_cgroup_from_obj(p);
803 * Untracked pages have no memcg, no lruvec. Update only the
804 * node. If we reparent the slab objects to the root memcg,
805 * when we free the slab object, we need to update the per-memcg
806 * vmstats to keep it correct for the root memcg.
809 __mod_node_page_state(pgdat, idx, val);
811 lruvec = mem_cgroup_lruvec(memcg, pgdat);
812 __mod_lruvec_state(lruvec, idx, val);
818 * mod_objcg_mlstate() may be called with irq enabled, so
819 * mod_memcg_lruvec_state() should be used.
821 static inline void mod_objcg_mlstate(struct obj_cgroup *objcg,
822 struct pglist_data *pgdat,
823 enum node_stat_item idx, int nr)
825 struct mem_cgroup *memcg;
826 struct lruvec *lruvec;
829 memcg = obj_cgroup_memcg(objcg);
830 lruvec = mem_cgroup_lruvec(memcg, pgdat);
831 mod_memcg_lruvec_state(lruvec, idx, nr);
836 * __count_memcg_events - account VM events in a cgroup
837 * @memcg: the memory cgroup
838 * @idx: the event item
839 * @count: the number of events that occurred
841 void __count_memcg_events(struct mem_cgroup *memcg, enum vm_event_item idx,
844 if (mem_cgroup_disabled())
847 __this_cpu_add(memcg->vmstats_percpu->events[idx], count);
848 memcg_rstat_updated(memcg, count);
851 static unsigned long memcg_events(struct mem_cgroup *memcg, int event)
853 return READ_ONCE(memcg->vmstats.events[event]);
856 static unsigned long memcg_events_local(struct mem_cgroup *memcg, int event)
861 for_each_possible_cpu(cpu)
862 x += per_cpu(memcg->vmstats_percpu->events[event], cpu);
866 static void mem_cgroup_charge_statistics(struct mem_cgroup *memcg,
870 /* pagein of a big page is an event. So, ignore page size */
872 __count_memcg_events(memcg, PGPGIN, 1);
874 __count_memcg_events(memcg, PGPGOUT, 1);
875 nr_pages = -nr_pages; /* for event */
878 __this_cpu_add(memcg->vmstats_percpu->nr_page_events, nr_pages);
881 static bool mem_cgroup_event_ratelimit(struct mem_cgroup *memcg,
882 enum mem_cgroup_events_target target)
884 unsigned long val, next;
886 val = __this_cpu_read(memcg->vmstats_percpu->nr_page_events);
887 next = __this_cpu_read(memcg->vmstats_percpu->targets[target]);
888 /* from time_after() in jiffies.h */
889 if ((long)(next - val) < 0) {
891 case MEM_CGROUP_TARGET_THRESH:
892 next = val + THRESHOLDS_EVENTS_TARGET;
894 case MEM_CGROUP_TARGET_SOFTLIMIT:
895 next = val + SOFTLIMIT_EVENTS_TARGET;
900 __this_cpu_write(memcg->vmstats_percpu->targets[target], next);
907 * Check events in order.
910 static void memcg_check_events(struct mem_cgroup *memcg, struct page *page)
912 /* threshold event is triggered in finer grain than soft limit */
913 if (unlikely(mem_cgroup_event_ratelimit(memcg,
914 MEM_CGROUP_TARGET_THRESH))) {
917 do_softlimit = mem_cgroup_event_ratelimit(memcg,
918 MEM_CGROUP_TARGET_SOFTLIMIT);
919 mem_cgroup_threshold(memcg);
920 if (unlikely(do_softlimit))
921 mem_cgroup_update_tree(memcg, page);
925 struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
928 * mm_update_next_owner() may clear mm->owner to NULL
929 * if it races with swapoff, page migration, etc.
930 * So this can be called with p == NULL.
935 return mem_cgroup_from_css(task_css(p, memory_cgrp_id));
937 EXPORT_SYMBOL(mem_cgroup_from_task);
939 static __always_inline struct mem_cgroup *active_memcg(void)
942 return this_cpu_read(int_active_memcg);
944 return current->active_memcg;
948 * get_mem_cgroup_from_mm: Obtain a reference on given mm_struct's memcg.
949 * @mm: mm from which memcg should be extracted. It can be NULL.
951 * Obtain a reference on mm->memcg and returns it if successful. If mm
952 * is NULL, then the memcg is chosen as follows:
953 * 1) The active memcg, if set.
954 * 2) current->mm->memcg, if available
956 * If mem_cgroup is disabled, NULL is returned.
958 struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm)
960 struct mem_cgroup *memcg;
962 if (mem_cgroup_disabled())
966 * Page cache insertions can happen without an
967 * actual mm context, e.g. during disk probing
968 * on boot, loopback IO, acct() writes etc.
970 * No need to css_get on root memcg as the reference
971 * counting is disabled on the root level in the
972 * cgroup core. See CSS_NO_REF.
975 memcg = active_memcg();
976 if (unlikely(memcg)) {
977 /* remote memcg must hold a ref */
978 css_get(&memcg->css);
983 return root_mem_cgroup;
988 memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
989 if (unlikely(!memcg))
990 memcg = root_mem_cgroup;
991 } while (!css_tryget(&memcg->css));
995 EXPORT_SYMBOL(get_mem_cgroup_from_mm);
997 static __always_inline bool memcg_kmem_bypass(void)
999 /* Allow remote memcg charging from any context. */
1000 if (unlikely(active_memcg()))
1003 /* Memcg to charge can't be determined. */
1004 if (!in_task() || !current->mm || (current->flags & PF_KTHREAD))
1011 * mem_cgroup_iter - iterate over memory cgroup hierarchy
1012 * @root: hierarchy root
1013 * @prev: previously returned memcg, NULL on first invocation
1014 * @reclaim: cookie for shared reclaim walks, NULL for full walks
1016 * Returns references to children of the hierarchy below @root, or
1017 * @root itself, or %NULL after a full round-trip.
1019 * Caller must pass the return value in @prev on subsequent
1020 * invocations for reference counting, or use mem_cgroup_iter_break()
1021 * to cancel a hierarchy walk before the round-trip is complete.
1023 * Reclaimers can specify a node in @reclaim to divide up the memcgs
1024 * in the hierarchy among all concurrent reclaimers operating on the
1027 struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root,
1028 struct mem_cgroup *prev,
1029 struct mem_cgroup_reclaim_cookie *reclaim)
1031 struct mem_cgroup_reclaim_iter *iter;
1032 struct cgroup_subsys_state *css = NULL;
1033 struct mem_cgroup *memcg = NULL;
1034 struct mem_cgroup *pos = NULL;
1036 if (mem_cgroup_disabled())
1040 root = root_mem_cgroup;
1042 if (prev && !reclaim)
1048 struct mem_cgroup_per_node *mz;
1050 mz = root->nodeinfo[reclaim->pgdat->node_id];
1053 if (prev && reclaim->generation != iter->generation)
1057 pos = READ_ONCE(iter->position);
1058 if (!pos || css_tryget(&pos->css))
1061 * css reference reached zero, so iter->position will
1062 * be cleared by ->css_released. However, we should not
1063 * rely on this happening soon, because ->css_released
1064 * is called from a work queue, and by busy-waiting we
1065 * might block it. So we clear iter->position right
1068 (void)cmpxchg(&iter->position, pos, NULL);
1076 css = css_next_descendant_pre(css, &root->css);
1079 * Reclaimers share the hierarchy walk, and a
1080 * new one might jump in right at the end of
1081 * the hierarchy - make sure they see at least
1082 * one group and restart from the beginning.
1090 * Verify the css and acquire a reference. The root
1091 * is provided by the caller, so we know it's alive
1092 * and kicking, and don't take an extra reference.
1094 memcg = mem_cgroup_from_css(css);
1096 if (css == &root->css)
1099 if (css_tryget(css))
1107 * The position could have already been updated by a competing
1108 * thread, so check that the value hasn't changed since we read
1109 * it to avoid reclaiming from the same cgroup twice.
1111 (void)cmpxchg(&iter->position, pos, memcg);
1119 reclaim->generation = iter->generation;
1124 if (prev && prev != root)
1125 css_put(&prev->css);
1131 * mem_cgroup_iter_break - abort a hierarchy walk prematurely
1132 * @root: hierarchy root
1133 * @prev: last visited hierarchy member as returned by mem_cgroup_iter()
1135 void mem_cgroup_iter_break(struct mem_cgroup *root,
1136 struct mem_cgroup *prev)
1139 root = root_mem_cgroup;
1140 if (prev && prev != root)
1141 css_put(&prev->css);
1144 static void __invalidate_reclaim_iterators(struct mem_cgroup *from,
1145 struct mem_cgroup *dead_memcg)
1147 struct mem_cgroup_reclaim_iter *iter;
1148 struct mem_cgroup_per_node *mz;
1151 for_each_node(nid) {
1152 mz = from->nodeinfo[nid];
1154 cmpxchg(&iter->position, dead_memcg, NULL);
1158 static void invalidate_reclaim_iterators(struct mem_cgroup *dead_memcg)
1160 struct mem_cgroup *memcg = dead_memcg;
1161 struct mem_cgroup *last;
1164 __invalidate_reclaim_iterators(memcg, dead_memcg);
1166 } while ((memcg = parent_mem_cgroup(memcg)));
1169 * When cgruop1 non-hierarchy mode is used,
1170 * parent_mem_cgroup() does not walk all the way up to the
1171 * cgroup root (root_mem_cgroup). So we have to handle
1172 * dead_memcg from cgroup root separately.
1174 if (last != root_mem_cgroup)
1175 __invalidate_reclaim_iterators(root_mem_cgroup,
1180 * mem_cgroup_scan_tasks - iterate over tasks of a memory cgroup hierarchy
1181 * @memcg: hierarchy root
1182 * @fn: function to call for each task
1183 * @arg: argument passed to @fn
1185 * This function iterates over tasks attached to @memcg or to any of its
1186 * descendants and calls @fn for each task. If @fn returns a non-zero
1187 * value, the function breaks the iteration loop and returns the value.
1188 * Otherwise, it will iterate over all tasks and return 0.
1190 * This function must not be called for the root memory cgroup.
1192 int mem_cgroup_scan_tasks(struct mem_cgroup *memcg,
1193 int (*fn)(struct task_struct *, void *), void *arg)
1195 struct mem_cgroup *iter;
1198 BUG_ON(memcg == root_mem_cgroup);
1200 for_each_mem_cgroup_tree(iter, memcg) {
1201 struct css_task_iter it;
1202 struct task_struct *task;
1204 css_task_iter_start(&iter->css, CSS_TASK_ITER_PROCS, &it);
1205 while (!ret && (task = css_task_iter_next(&it)))
1206 ret = fn(task, arg);
1207 css_task_iter_end(&it);
1209 mem_cgroup_iter_break(memcg, iter);
1216 #ifdef CONFIG_DEBUG_VM
1217 void lruvec_memcg_debug(struct lruvec *lruvec, struct page *page)
1219 struct mem_cgroup *memcg;
1221 if (mem_cgroup_disabled())
1224 memcg = page_memcg(page);
1227 VM_BUG_ON_PAGE(lruvec_memcg(lruvec) != root_mem_cgroup, page);
1229 VM_BUG_ON_PAGE(lruvec_memcg(lruvec) != memcg, page);
1234 * lock_page_lruvec - lock and return lruvec for a given page.
1237 * These functions are safe to use under any of the following conditions:
1240 * - lock_page_memcg()
1241 * - page->_refcount is zero
1243 struct lruvec *lock_page_lruvec(struct page *page)
1245 struct lruvec *lruvec;
1247 lruvec = mem_cgroup_page_lruvec(page);
1248 spin_lock(&lruvec->lru_lock);
1250 lruvec_memcg_debug(lruvec, page);
1255 struct lruvec *lock_page_lruvec_irq(struct page *page)
1257 struct lruvec *lruvec;
1259 lruvec = mem_cgroup_page_lruvec(page);
1260 spin_lock_irq(&lruvec->lru_lock);
1262 lruvec_memcg_debug(lruvec, page);
1267 struct lruvec *lock_page_lruvec_irqsave(struct page *page, unsigned long *flags)
1269 struct lruvec *lruvec;
1271 lruvec = mem_cgroup_page_lruvec(page);
1272 spin_lock_irqsave(&lruvec->lru_lock, *flags);
1274 lruvec_memcg_debug(lruvec, page);
1280 * mem_cgroup_update_lru_size - account for adding or removing an lru page
1281 * @lruvec: mem_cgroup per zone lru vector
1282 * @lru: index of lru list the page is sitting on
1283 * @zid: zone id of the accounted pages
1284 * @nr_pages: positive when adding or negative when removing
1286 * This function must be called under lru_lock, just before a page is added
1287 * to or just after a page is removed from an lru list (that ordering being
1288 * so as to allow it to check that lru_size 0 is consistent with list_empty).
1290 void mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru,
1291 int zid, int nr_pages)
1293 struct mem_cgroup_per_node *mz;
1294 unsigned long *lru_size;
1297 if (mem_cgroup_disabled())
1300 mz = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
1301 lru_size = &mz->lru_zone_size[zid][lru];
1304 *lru_size += nr_pages;
1307 if (WARN_ONCE(size < 0,
1308 "%s(%p, %d, %d): lru_size %ld\n",
1309 __func__, lruvec, lru, nr_pages, size)) {
1315 *lru_size += nr_pages;
1319 * mem_cgroup_margin - calculate chargeable space of a memory cgroup
1320 * @memcg: the memory cgroup
1322 * Returns the maximum amount of memory @mem can be charged with, in
1325 static unsigned long mem_cgroup_margin(struct mem_cgroup *memcg)
1327 unsigned long margin = 0;
1328 unsigned long count;
1329 unsigned long limit;
1331 count = page_counter_read(&memcg->memory);
1332 limit = READ_ONCE(memcg->memory.max);
1334 margin = limit - count;
1336 if (do_memsw_account()) {
1337 count = page_counter_read(&memcg->memsw);
1338 limit = READ_ONCE(memcg->memsw.max);
1340 margin = min(margin, limit - count);
1349 * A routine for checking "mem" is under move_account() or not.
1351 * Checking a cgroup is mc.from or mc.to or under hierarchy of
1352 * moving cgroups. This is for waiting at high-memory pressure
1355 static bool mem_cgroup_under_move(struct mem_cgroup *memcg)
1357 struct mem_cgroup *from;
1358 struct mem_cgroup *to;
1361 * Unlike task_move routines, we access mc.to, mc.from not under
1362 * mutual exclusion by cgroup_mutex. Here, we take spinlock instead.
1364 spin_lock(&mc.lock);
1370 ret = mem_cgroup_is_descendant(from, memcg) ||
1371 mem_cgroup_is_descendant(to, memcg);
1373 spin_unlock(&mc.lock);
1377 static bool mem_cgroup_wait_acct_move(struct mem_cgroup *memcg)
1379 if (mc.moving_task && current != mc.moving_task) {
1380 if (mem_cgroup_under_move(memcg)) {
1382 prepare_to_wait(&mc.waitq, &wait, TASK_INTERRUPTIBLE);
1383 /* moving charge context might have finished. */
1386 finish_wait(&mc.waitq, &wait);
1393 struct memory_stat {
1398 static const struct memory_stat memory_stats[] = {
1399 { "anon", NR_ANON_MAPPED },
1400 { "file", NR_FILE_PAGES },
1401 { "kernel_stack", NR_KERNEL_STACK_KB },
1402 { "pagetables", NR_PAGETABLE },
1403 { "percpu", MEMCG_PERCPU_B },
1404 { "sock", MEMCG_SOCK },
1405 { "shmem", NR_SHMEM },
1406 { "file_mapped", NR_FILE_MAPPED },
1407 { "file_dirty", NR_FILE_DIRTY },
1408 { "file_writeback", NR_WRITEBACK },
1410 { "swapcached", NR_SWAPCACHE },
1412 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
1413 { "anon_thp", NR_ANON_THPS },
1414 { "file_thp", NR_FILE_THPS },
1415 { "shmem_thp", NR_SHMEM_THPS },
1417 { "inactive_anon", NR_INACTIVE_ANON },
1418 { "active_anon", NR_ACTIVE_ANON },
1419 { "inactive_file", NR_INACTIVE_FILE },
1420 { "active_file", NR_ACTIVE_FILE },
1421 { "unevictable", NR_UNEVICTABLE },
1422 { "slab_reclaimable", NR_SLAB_RECLAIMABLE_B },
1423 { "slab_unreclaimable", NR_SLAB_UNRECLAIMABLE_B },
1425 /* The memory events */
1426 { "workingset_refault_anon", WORKINGSET_REFAULT_ANON },
1427 { "workingset_refault_file", WORKINGSET_REFAULT_FILE },
1428 { "workingset_activate_anon", WORKINGSET_ACTIVATE_ANON },
1429 { "workingset_activate_file", WORKINGSET_ACTIVATE_FILE },
1430 { "workingset_restore_anon", WORKINGSET_RESTORE_ANON },
1431 { "workingset_restore_file", WORKINGSET_RESTORE_FILE },
1432 { "workingset_nodereclaim", WORKINGSET_NODERECLAIM },
1435 /* Translate stat items to the correct unit for memory.stat output */
1436 static int memcg_page_state_unit(int item)
1439 case MEMCG_PERCPU_B:
1440 case NR_SLAB_RECLAIMABLE_B:
1441 case NR_SLAB_UNRECLAIMABLE_B:
1442 case WORKINGSET_REFAULT_ANON:
1443 case WORKINGSET_REFAULT_FILE:
1444 case WORKINGSET_ACTIVATE_ANON:
1445 case WORKINGSET_ACTIVATE_FILE:
1446 case WORKINGSET_RESTORE_ANON:
1447 case WORKINGSET_RESTORE_FILE:
1448 case WORKINGSET_NODERECLAIM:
1450 case NR_KERNEL_STACK_KB:
1457 static inline unsigned long memcg_page_state_output(struct mem_cgroup *memcg,
1460 return memcg_page_state(memcg, item) * memcg_page_state_unit(item);
1463 static char *memory_stat_format(struct mem_cgroup *memcg)
1468 seq_buf_init(&s, kmalloc(PAGE_SIZE, GFP_KERNEL), PAGE_SIZE);
1473 * Provide statistics on the state of the memory subsystem as
1474 * well as cumulative event counters that show past behavior.
1476 * This list is ordered following a combination of these gradients:
1477 * 1) generic big picture -> specifics and details
1478 * 2) reflecting userspace activity -> reflecting kernel heuristics
1480 * Current memory state:
1482 mem_cgroup_flush_stats();
1484 for (i = 0; i < ARRAY_SIZE(memory_stats); i++) {
1487 size = memcg_page_state_output(memcg, memory_stats[i].idx);
1488 seq_buf_printf(&s, "%s %llu\n", memory_stats[i].name, size);
1490 if (unlikely(memory_stats[i].idx == NR_SLAB_UNRECLAIMABLE_B)) {
1491 size += memcg_page_state_output(memcg,
1492 NR_SLAB_RECLAIMABLE_B);
1493 seq_buf_printf(&s, "slab %llu\n", size);
1497 /* Accumulated memory events */
1499 seq_buf_printf(&s, "%s %lu\n", vm_event_name(PGFAULT),
1500 memcg_events(memcg, PGFAULT));
1501 seq_buf_printf(&s, "%s %lu\n", vm_event_name(PGMAJFAULT),
1502 memcg_events(memcg, PGMAJFAULT));
1503 seq_buf_printf(&s, "%s %lu\n", vm_event_name(PGREFILL),
1504 memcg_events(memcg, PGREFILL));
1505 seq_buf_printf(&s, "pgscan %lu\n",
1506 memcg_events(memcg, PGSCAN_KSWAPD) +
1507 memcg_events(memcg, PGSCAN_DIRECT));
1508 seq_buf_printf(&s, "pgsteal %lu\n",
1509 memcg_events(memcg, PGSTEAL_KSWAPD) +
1510 memcg_events(memcg, PGSTEAL_DIRECT));
1511 seq_buf_printf(&s, "%s %lu\n", vm_event_name(PGACTIVATE),
1512 memcg_events(memcg, PGACTIVATE));
1513 seq_buf_printf(&s, "%s %lu\n", vm_event_name(PGDEACTIVATE),
1514 memcg_events(memcg, PGDEACTIVATE));
1515 seq_buf_printf(&s, "%s %lu\n", vm_event_name(PGLAZYFREE),
1516 memcg_events(memcg, PGLAZYFREE));
1517 seq_buf_printf(&s, "%s %lu\n", vm_event_name(PGLAZYFREED),
1518 memcg_events(memcg, PGLAZYFREED));
1520 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
1521 seq_buf_printf(&s, "%s %lu\n", vm_event_name(THP_FAULT_ALLOC),
1522 memcg_events(memcg, THP_FAULT_ALLOC));
1523 seq_buf_printf(&s, "%s %lu\n", vm_event_name(THP_COLLAPSE_ALLOC),
1524 memcg_events(memcg, THP_COLLAPSE_ALLOC));
1525 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
1527 /* The above should easily fit into one page */
1528 WARN_ON_ONCE(seq_buf_has_overflowed(&s));
1533 #define K(x) ((x) << (PAGE_SHIFT-10))
1535 * mem_cgroup_print_oom_context: Print OOM information relevant to
1536 * memory controller.
1537 * @memcg: The memory cgroup that went over limit
1538 * @p: Task that is going to be killed
1540 * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is
1543 void mem_cgroup_print_oom_context(struct mem_cgroup *memcg, struct task_struct *p)
1548 pr_cont(",oom_memcg=");
1549 pr_cont_cgroup_path(memcg->css.cgroup);
1551 pr_cont(",global_oom");
1553 pr_cont(",task_memcg=");
1554 pr_cont_cgroup_path(task_cgroup(p, memory_cgrp_id));
1560 * mem_cgroup_print_oom_meminfo: Print OOM memory information relevant to
1561 * memory controller.
1562 * @memcg: The memory cgroup that went over limit
1564 void mem_cgroup_print_oom_meminfo(struct mem_cgroup *memcg)
1568 pr_info("memory: usage %llukB, limit %llukB, failcnt %lu\n",
1569 K((u64)page_counter_read(&memcg->memory)),
1570 K((u64)READ_ONCE(memcg->memory.max)), memcg->memory.failcnt);
1571 if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
1572 pr_info("swap: usage %llukB, limit %llukB, failcnt %lu\n",
1573 K((u64)page_counter_read(&memcg->swap)),
1574 K((u64)READ_ONCE(memcg->swap.max)), memcg->swap.failcnt);
1576 pr_info("memory+swap: usage %llukB, limit %llukB, failcnt %lu\n",
1577 K((u64)page_counter_read(&memcg->memsw)),
1578 K((u64)memcg->memsw.max), memcg->memsw.failcnt);
1579 pr_info("kmem: usage %llukB, limit %llukB, failcnt %lu\n",
1580 K((u64)page_counter_read(&memcg->kmem)),
1581 K((u64)memcg->kmem.max), memcg->kmem.failcnt);
1584 pr_info("Memory cgroup stats for ");
1585 pr_cont_cgroup_path(memcg->css.cgroup);
1587 buf = memory_stat_format(memcg);
1595 * Return the memory (and swap, if configured) limit for a memcg.
1597 unsigned long mem_cgroup_get_max(struct mem_cgroup *memcg)
1599 unsigned long max = READ_ONCE(memcg->memory.max);
1601 if (cgroup_subsys_on_dfl(memory_cgrp_subsys)) {
1602 if (mem_cgroup_swappiness(memcg))
1603 max += min(READ_ONCE(memcg->swap.max),
1604 (unsigned long)total_swap_pages);
1606 if (mem_cgroup_swappiness(memcg)) {
1607 /* Calculate swap excess capacity from memsw limit */
1608 unsigned long swap = READ_ONCE(memcg->memsw.max) - max;
1610 max += min(swap, (unsigned long)total_swap_pages);
1616 unsigned long mem_cgroup_size(struct mem_cgroup *memcg)
1618 return page_counter_read(&memcg->memory);
1621 static bool mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask,
1624 struct oom_control oc = {
1628 .gfp_mask = gfp_mask,
1633 if (mutex_lock_killable(&oom_lock))
1636 if (mem_cgroup_margin(memcg) >= (1 << order))
1640 * A few threads which were not waiting at mutex_lock_killable() can
1641 * fail to bail out. Therefore, check again after holding oom_lock.
1643 ret = task_is_dying() || out_of_memory(&oc);
1646 mutex_unlock(&oom_lock);
1650 static int mem_cgroup_soft_reclaim(struct mem_cgroup *root_memcg,
1653 unsigned long *total_scanned)
1655 struct mem_cgroup *victim = NULL;
1658 unsigned long excess;
1659 unsigned long nr_scanned;
1660 struct mem_cgroup_reclaim_cookie reclaim = {
1664 excess = soft_limit_excess(root_memcg);
1667 victim = mem_cgroup_iter(root_memcg, victim, &reclaim);
1672 * If we have not been able to reclaim
1673 * anything, it might because there are
1674 * no reclaimable pages under this hierarchy
1679 * We want to do more targeted reclaim.
1680 * excess >> 2 is not to excessive so as to
1681 * reclaim too much, nor too less that we keep
1682 * coming back to reclaim from this cgroup
1684 if (total >= (excess >> 2) ||
1685 (loop > MEM_CGROUP_MAX_RECLAIM_LOOPS))
1690 total += mem_cgroup_shrink_node(victim, gfp_mask, false,
1691 pgdat, &nr_scanned);
1692 *total_scanned += nr_scanned;
1693 if (!soft_limit_excess(root_memcg))
1696 mem_cgroup_iter_break(root_memcg, victim);
1700 #ifdef CONFIG_LOCKDEP
1701 static struct lockdep_map memcg_oom_lock_dep_map = {
1702 .name = "memcg_oom_lock",
1706 static DEFINE_SPINLOCK(memcg_oom_lock);
1709 * Check OOM-Killer is already running under our hierarchy.
1710 * If someone is running, return false.
1712 static bool mem_cgroup_oom_trylock(struct mem_cgroup *memcg)
1714 struct mem_cgroup *iter, *failed = NULL;
1716 spin_lock(&memcg_oom_lock);
1718 for_each_mem_cgroup_tree(iter, memcg) {
1719 if (iter->oom_lock) {
1721 * this subtree of our hierarchy is already locked
1722 * so we cannot give a lock.
1725 mem_cgroup_iter_break(memcg, iter);
1728 iter->oom_lock = true;
1733 * OK, we failed to lock the whole subtree so we have
1734 * to clean up what we set up to the failing subtree
1736 for_each_mem_cgroup_tree(iter, memcg) {
1737 if (iter == failed) {
1738 mem_cgroup_iter_break(memcg, iter);
1741 iter->oom_lock = false;
1744 mutex_acquire(&memcg_oom_lock_dep_map, 0, 1, _RET_IP_);
1746 spin_unlock(&memcg_oom_lock);
1751 static void mem_cgroup_oom_unlock(struct mem_cgroup *memcg)
1753 struct mem_cgroup *iter;
1755 spin_lock(&memcg_oom_lock);
1756 mutex_release(&memcg_oom_lock_dep_map, _RET_IP_);
1757 for_each_mem_cgroup_tree(iter, memcg)
1758 iter->oom_lock = false;
1759 spin_unlock(&memcg_oom_lock);
1762 static void mem_cgroup_mark_under_oom(struct mem_cgroup *memcg)
1764 struct mem_cgroup *iter;
1766 spin_lock(&memcg_oom_lock);
1767 for_each_mem_cgroup_tree(iter, memcg)
1769 spin_unlock(&memcg_oom_lock);
1772 static void mem_cgroup_unmark_under_oom(struct mem_cgroup *memcg)
1774 struct mem_cgroup *iter;
1777 * Be careful about under_oom underflows because a child memcg
1778 * could have been added after mem_cgroup_mark_under_oom.
1780 spin_lock(&memcg_oom_lock);
1781 for_each_mem_cgroup_tree(iter, memcg)
1782 if (iter->under_oom > 0)
1784 spin_unlock(&memcg_oom_lock);
1787 static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq);
1789 struct oom_wait_info {
1790 struct mem_cgroup *memcg;
1791 wait_queue_entry_t wait;
1794 static int memcg_oom_wake_function(wait_queue_entry_t *wait,
1795 unsigned mode, int sync, void *arg)
1797 struct mem_cgroup *wake_memcg = (struct mem_cgroup *)arg;
1798 struct mem_cgroup *oom_wait_memcg;
1799 struct oom_wait_info *oom_wait_info;
1801 oom_wait_info = container_of(wait, struct oom_wait_info, wait);
1802 oom_wait_memcg = oom_wait_info->memcg;
1804 if (!mem_cgroup_is_descendant(wake_memcg, oom_wait_memcg) &&
1805 !mem_cgroup_is_descendant(oom_wait_memcg, wake_memcg))
1807 return autoremove_wake_function(wait, mode, sync, arg);
1810 static void memcg_oom_recover(struct mem_cgroup *memcg)
1813 * For the following lockless ->under_oom test, the only required
1814 * guarantee is that it must see the state asserted by an OOM when
1815 * this function is called as a result of userland actions
1816 * triggered by the notification of the OOM. This is trivially
1817 * achieved by invoking mem_cgroup_mark_under_oom() before
1818 * triggering notification.
1820 if (memcg && memcg->under_oom)
1821 __wake_up(&memcg_oom_waitq, TASK_NORMAL, 0, memcg);
1831 static enum oom_status mem_cgroup_oom(struct mem_cgroup *memcg, gfp_t mask, int order)
1833 enum oom_status ret;
1836 if (order > PAGE_ALLOC_COSTLY_ORDER)
1839 memcg_memory_event(memcg, MEMCG_OOM);
1842 * We are in the middle of the charge context here, so we
1843 * don't want to block when potentially sitting on a callstack
1844 * that holds all kinds of filesystem and mm locks.
1846 * cgroup1 allows disabling the OOM killer and waiting for outside
1847 * handling until the charge can succeed; remember the context and put
1848 * the task to sleep at the end of the page fault when all locks are
1851 * On the other hand, in-kernel OOM killer allows for an async victim
1852 * memory reclaim (oom_reaper) and that means that we are not solely
1853 * relying on the oom victim to make a forward progress and we can
1854 * invoke the oom killer here.
1856 * Please note that mem_cgroup_out_of_memory might fail to find a
1857 * victim and then we have to bail out from the charge path.
1859 if (memcg->oom_kill_disable) {
1860 if (!current->in_user_fault)
1862 css_get(&memcg->css);
1863 current->memcg_in_oom = memcg;
1864 current->memcg_oom_gfp_mask = mask;
1865 current->memcg_oom_order = order;
1870 mem_cgroup_mark_under_oom(memcg);
1872 locked = mem_cgroup_oom_trylock(memcg);
1875 mem_cgroup_oom_notify(memcg);
1877 mem_cgroup_unmark_under_oom(memcg);
1878 if (mem_cgroup_out_of_memory(memcg, mask, order))
1884 mem_cgroup_oom_unlock(memcg);
1890 * mem_cgroup_oom_synchronize - complete memcg OOM handling
1891 * @handle: actually kill/wait or just clean up the OOM state
1893 * This has to be called at the end of a page fault if the memcg OOM
1894 * handler was enabled.
1896 * Memcg supports userspace OOM handling where failed allocations must
1897 * sleep on a waitqueue until the userspace task resolves the
1898 * situation. Sleeping directly in the charge context with all kinds
1899 * of locks held is not a good idea, instead we remember an OOM state
1900 * in the task and mem_cgroup_oom_synchronize() has to be called at
1901 * the end of the page fault to complete the OOM handling.
1903 * Returns %true if an ongoing memcg OOM situation was detected and
1904 * completed, %false otherwise.
1906 bool mem_cgroup_oom_synchronize(bool handle)
1908 struct mem_cgroup *memcg = current->memcg_in_oom;
1909 struct oom_wait_info owait;
1912 /* OOM is global, do not handle */
1919 owait.memcg = memcg;
1920 owait.wait.flags = 0;
1921 owait.wait.func = memcg_oom_wake_function;
1922 owait.wait.private = current;
1923 INIT_LIST_HEAD(&owait.wait.entry);
1925 prepare_to_wait(&memcg_oom_waitq, &owait.wait, TASK_KILLABLE);
1926 mem_cgroup_mark_under_oom(memcg);
1928 locked = mem_cgroup_oom_trylock(memcg);
1931 mem_cgroup_oom_notify(memcg);
1933 if (locked && !memcg->oom_kill_disable) {
1934 mem_cgroup_unmark_under_oom(memcg);
1935 finish_wait(&memcg_oom_waitq, &owait.wait);
1936 mem_cgroup_out_of_memory(memcg, current->memcg_oom_gfp_mask,
1937 current->memcg_oom_order);
1940 mem_cgroup_unmark_under_oom(memcg);
1941 finish_wait(&memcg_oom_waitq, &owait.wait);
1945 mem_cgroup_oom_unlock(memcg);
1947 * There is no guarantee that an OOM-lock contender
1948 * sees the wakeups triggered by the OOM kill
1949 * uncharges. Wake any sleepers explicitly.
1951 memcg_oom_recover(memcg);
1954 current->memcg_in_oom = NULL;
1955 css_put(&memcg->css);
1960 * mem_cgroup_get_oom_group - get a memory cgroup to clean up after OOM
1961 * @victim: task to be killed by the OOM killer
1962 * @oom_domain: memcg in case of memcg OOM, NULL in case of system-wide OOM
1964 * Returns a pointer to a memory cgroup, which has to be cleaned up
1965 * by killing all belonging OOM-killable tasks.
1967 * Caller has to call mem_cgroup_put() on the returned non-NULL memcg.
1969 struct mem_cgroup *mem_cgroup_get_oom_group(struct task_struct *victim,
1970 struct mem_cgroup *oom_domain)
1972 struct mem_cgroup *oom_group = NULL;
1973 struct mem_cgroup *memcg;
1975 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys))
1979 oom_domain = root_mem_cgroup;
1983 memcg = mem_cgroup_from_task(victim);
1984 if (memcg == root_mem_cgroup)
1988 * If the victim task has been asynchronously moved to a different
1989 * memory cgroup, we might end up killing tasks outside oom_domain.
1990 * In this case it's better to ignore memory.group.oom.
1992 if (unlikely(!mem_cgroup_is_descendant(memcg, oom_domain)))
1996 * Traverse the memory cgroup hierarchy from the victim task's
1997 * cgroup up to the OOMing cgroup (or root) to find the
1998 * highest-level memory cgroup with oom.group set.
2000 for (; memcg; memcg = parent_mem_cgroup(memcg)) {
2001 if (memcg->oom_group)
2004 if (memcg == oom_domain)
2009 css_get(&oom_group->css);
2016 void mem_cgroup_print_oom_group(struct mem_cgroup *memcg)
2018 pr_info("Tasks in ");
2019 pr_cont_cgroup_path(memcg->css.cgroup);
2020 pr_cont(" are going to be killed due to memory.oom.group set\n");
2024 * lock_page_memcg - lock a page and memcg binding
2027 * This function protects unlocked LRU pages from being moved to
2030 * It ensures lifetime of the locked memcg. Caller is responsible
2031 * for the lifetime of the page.
2033 void lock_page_memcg(struct page *page)
2035 struct page *head = compound_head(page); /* rmap on tail pages */
2036 struct mem_cgroup *memcg;
2037 unsigned long flags;
2040 * The RCU lock is held throughout the transaction. The fast
2041 * path can get away without acquiring the memcg->move_lock
2042 * because page moving starts with an RCU grace period.
2046 if (mem_cgroup_disabled())
2049 memcg = page_memcg(head);
2050 if (unlikely(!memcg))
2053 #ifdef CONFIG_PROVE_LOCKING
2054 local_irq_save(flags);
2055 might_lock(&memcg->move_lock);
2056 local_irq_restore(flags);
2059 if (atomic_read(&memcg->moving_account) <= 0)
2062 spin_lock_irqsave(&memcg->move_lock, flags);
2063 if (memcg != page_memcg(head)) {
2064 spin_unlock_irqrestore(&memcg->move_lock, flags);
2069 * When charge migration first begins, we can have multiple
2070 * critical sections holding the fast-path RCU lock and one
2071 * holding the slowpath move_lock. Track the task who has the
2072 * move_lock for unlock_page_memcg().
2074 memcg->move_lock_task = current;
2075 memcg->move_lock_flags = flags;
2077 EXPORT_SYMBOL(lock_page_memcg);
2079 static void __unlock_page_memcg(struct mem_cgroup *memcg)
2081 if (memcg && memcg->move_lock_task == current) {
2082 unsigned long flags = memcg->move_lock_flags;
2084 memcg->move_lock_task = NULL;
2085 memcg->move_lock_flags = 0;
2087 spin_unlock_irqrestore(&memcg->move_lock, flags);
2094 * unlock_page_memcg - unlock a page and memcg binding
2097 void unlock_page_memcg(struct page *page)
2099 struct page *head = compound_head(page);
2101 __unlock_page_memcg(page_memcg(head));
2103 EXPORT_SYMBOL(unlock_page_memcg);
2106 #ifdef CONFIG_MEMCG_KMEM
2107 struct obj_cgroup *cached_objcg;
2108 struct pglist_data *cached_pgdat;
2109 unsigned int nr_bytes;
2110 int nr_slab_reclaimable_b;
2111 int nr_slab_unreclaimable_b;
2117 struct memcg_stock_pcp {
2118 struct mem_cgroup *cached; /* this never be root cgroup */
2119 unsigned int nr_pages;
2120 struct obj_stock task_obj;
2121 struct obj_stock irq_obj;
2123 struct work_struct work;
2124 unsigned long flags;
2125 #define FLUSHING_CACHED_CHARGE 0
2127 static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock);
2128 static DEFINE_MUTEX(percpu_charge_mutex);
2130 #ifdef CONFIG_MEMCG_KMEM
2131 static void drain_obj_stock(struct obj_stock *stock);
2132 static bool obj_stock_flush_required(struct memcg_stock_pcp *stock,
2133 struct mem_cgroup *root_memcg);
2136 static inline void drain_obj_stock(struct obj_stock *stock)
2139 static bool obj_stock_flush_required(struct memcg_stock_pcp *stock,
2140 struct mem_cgroup *root_memcg)
2147 * Most kmem_cache_alloc() calls are from user context. The irq disable/enable
2148 * sequence used in this case to access content from object stock is slow.
2149 * To optimize for user context access, there are now two object stocks for
2150 * task context and interrupt context access respectively.
2152 * The task context object stock can be accessed by disabling preemption only
2153 * which is cheap in non-preempt kernel. The interrupt context object stock
2154 * can only be accessed after disabling interrupt. User context code can
2155 * access interrupt object stock, but not vice versa.
2157 static inline struct obj_stock *get_obj_stock(unsigned long *pflags)
2159 struct memcg_stock_pcp *stock;
2161 if (likely(in_task())) {
2164 stock = this_cpu_ptr(&memcg_stock);
2165 return &stock->task_obj;
2168 local_irq_save(*pflags);
2169 stock = this_cpu_ptr(&memcg_stock);
2170 return &stock->irq_obj;
2173 static inline void put_obj_stock(unsigned long flags)
2175 if (likely(in_task()))
2178 local_irq_restore(flags);
2182 * consume_stock: Try to consume stocked charge on this cpu.
2183 * @memcg: memcg to consume from.
2184 * @nr_pages: how many pages to charge.
2186 * The charges will only happen if @memcg matches the current cpu's memcg
2187 * stock, and at least @nr_pages are available in that stock. Failure to
2188 * service an allocation will refill the stock.
2190 * returns true if successful, false otherwise.
2192 static bool consume_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
2194 struct memcg_stock_pcp *stock;
2195 unsigned long flags;
2198 if (nr_pages > MEMCG_CHARGE_BATCH)
2201 local_irq_save(flags);
2203 stock = this_cpu_ptr(&memcg_stock);
2204 if (memcg == stock->cached && stock->nr_pages >= nr_pages) {
2205 stock->nr_pages -= nr_pages;
2209 local_irq_restore(flags);
2215 * Returns stocks cached in percpu and reset cached information.
2217 static void drain_stock(struct memcg_stock_pcp *stock)
2219 struct mem_cgroup *old = stock->cached;
2224 if (stock->nr_pages) {
2225 page_counter_uncharge(&old->memory, stock->nr_pages);
2226 if (do_memsw_account())
2227 page_counter_uncharge(&old->memsw, stock->nr_pages);
2228 stock->nr_pages = 0;
2232 stock->cached = NULL;
2235 static void drain_local_stock(struct work_struct *dummy)
2237 struct memcg_stock_pcp *stock;
2238 unsigned long flags;
2241 * The only protection from cpu hotplug (memcg_hotplug_cpu_dead) vs.
2242 * drain_stock races is that we always operate on local CPU stock
2243 * here with IRQ disabled
2245 local_irq_save(flags);
2247 stock = this_cpu_ptr(&memcg_stock);
2248 drain_obj_stock(&stock->irq_obj);
2250 drain_obj_stock(&stock->task_obj);
2252 clear_bit(FLUSHING_CACHED_CHARGE, &stock->flags);
2254 local_irq_restore(flags);
2258 * Cache charges(val) to local per_cpu area.
2259 * This will be consumed by consume_stock() function, later.
2261 static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
2263 struct memcg_stock_pcp *stock;
2264 unsigned long flags;
2266 local_irq_save(flags);
2268 stock = this_cpu_ptr(&memcg_stock);
2269 if (stock->cached != memcg) { /* reset if necessary */
2271 css_get(&memcg->css);
2272 stock->cached = memcg;
2274 stock->nr_pages += nr_pages;
2276 if (stock->nr_pages > MEMCG_CHARGE_BATCH)
2279 local_irq_restore(flags);
2283 * Drains all per-CPU charge caches for given root_memcg resp. subtree
2284 * of the hierarchy under it.
2286 static void drain_all_stock(struct mem_cgroup *root_memcg)
2290 /* If someone's already draining, avoid adding running more workers. */
2291 if (!mutex_trylock(&percpu_charge_mutex))
2294 * Notify other cpus that system-wide "drain" is running
2295 * We do not care about races with the cpu hotplug because cpu down
2296 * as well as workers from this path always operate on the local
2297 * per-cpu data. CPU up doesn't touch memcg_stock at all.
2300 for_each_online_cpu(cpu) {
2301 struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
2302 struct mem_cgroup *memcg;
2306 memcg = stock->cached;
2307 if (memcg && stock->nr_pages &&
2308 mem_cgroup_is_descendant(memcg, root_memcg))
2310 else if (obj_stock_flush_required(stock, root_memcg))
2315 !test_and_set_bit(FLUSHING_CACHED_CHARGE, &stock->flags)) {
2317 drain_local_stock(&stock->work);
2319 schedule_work_on(cpu, &stock->work);
2323 mutex_unlock(&percpu_charge_mutex);
2326 static int memcg_hotplug_cpu_dead(unsigned int cpu)
2328 struct memcg_stock_pcp *stock;
2330 stock = &per_cpu(memcg_stock, cpu);
2336 static unsigned long reclaim_high(struct mem_cgroup *memcg,
2337 unsigned int nr_pages,
2340 unsigned long nr_reclaimed = 0;
2343 unsigned long pflags;
2345 if (page_counter_read(&memcg->memory) <=
2346 READ_ONCE(memcg->memory.high))
2349 memcg_memory_event(memcg, MEMCG_HIGH);
2351 psi_memstall_enter(&pflags);
2352 nr_reclaimed += try_to_free_mem_cgroup_pages(memcg, nr_pages,
2354 psi_memstall_leave(&pflags);
2355 } while ((memcg = parent_mem_cgroup(memcg)) &&
2356 !mem_cgroup_is_root(memcg));
2358 return nr_reclaimed;
2361 static void high_work_func(struct work_struct *work)
2363 struct mem_cgroup *memcg;
2365 memcg = container_of(work, struct mem_cgroup, high_work);
2366 reclaim_high(memcg, MEMCG_CHARGE_BATCH, GFP_KERNEL);
2370 * Clamp the maximum sleep time per allocation batch to 2 seconds. This is
2371 * enough to still cause a significant slowdown in most cases, while still
2372 * allowing diagnostics and tracing to proceed without becoming stuck.
2374 #define MEMCG_MAX_HIGH_DELAY_JIFFIES (2UL*HZ)
2377 * When calculating the delay, we use these either side of the exponentiation to
2378 * maintain precision and scale to a reasonable number of jiffies (see the table
2381 * - MEMCG_DELAY_PRECISION_SHIFT: Extra precision bits while translating the
2382 * overage ratio to a delay.
2383 * - MEMCG_DELAY_SCALING_SHIFT: The number of bits to scale down the
2384 * proposed penalty in order to reduce to a reasonable number of jiffies, and
2385 * to produce a reasonable delay curve.
2387 * MEMCG_DELAY_SCALING_SHIFT just happens to be a number that produces a
2388 * reasonable delay curve compared to precision-adjusted overage, not
2389 * penalising heavily at first, but still making sure that growth beyond the
2390 * limit penalises misbehaviour cgroups by slowing them down exponentially. For
2391 * example, with a high of 100 megabytes:
2393 * +-------+------------------------+
2394 * | usage | time to allocate in ms |
2395 * +-------+------------------------+
2417 * +-------+------------------------+
2419 #define MEMCG_DELAY_PRECISION_SHIFT 20
2420 #define MEMCG_DELAY_SCALING_SHIFT 14
2422 static u64 calculate_overage(unsigned long usage, unsigned long high)
2430 * Prevent division by 0 in overage calculation by acting as if
2431 * it was a threshold of 1 page
2433 high = max(high, 1UL);
2435 overage = usage - high;
2436 overage <<= MEMCG_DELAY_PRECISION_SHIFT;
2437 return div64_u64(overage, high);
2440 static u64 mem_find_max_overage(struct mem_cgroup *memcg)
2442 u64 overage, max_overage = 0;
2445 overage = calculate_overage(page_counter_read(&memcg->memory),
2446 READ_ONCE(memcg->memory.high));
2447 max_overage = max(overage, max_overage);
2448 } while ((memcg = parent_mem_cgroup(memcg)) &&
2449 !mem_cgroup_is_root(memcg));
2454 static u64 swap_find_max_overage(struct mem_cgroup *memcg)
2456 u64 overage, max_overage = 0;
2459 overage = calculate_overage(page_counter_read(&memcg->swap),
2460 READ_ONCE(memcg->swap.high));
2462 memcg_memory_event(memcg, MEMCG_SWAP_HIGH);
2463 max_overage = max(overage, max_overage);
2464 } while ((memcg = parent_mem_cgroup(memcg)) &&
2465 !mem_cgroup_is_root(memcg));
2471 * Get the number of jiffies that we should penalise a mischievous cgroup which
2472 * is exceeding its memory.high by checking both it and its ancestors.
2474 static unsigned long calculate_high_delay(struct mem_cgroup *memcg,
2475 unsigned int nr_pages,
2478 unsigned long penalty_jiffies;
2484 * We use overage compared to memory.high to calculate the number of
2485 * jiffies to sleep (penalty_jiffies). Ideally this value should be
2486 * fairly lenient on small overages, and increasingly harsh when the
2487 * memcg in question makes it clear that it has no intention of stopping
2488 * its crazy behaviour, so we exponentially increase the delay based on
2491 penalty_jiffies = max_overage * max_overage * HZ;
2492 penalty_jiffies >>= MEMCG_DELAY_PRECISION_SHIFT;
2493 penalty_jiffies >>= MEMCG_DELAY_SCALING_SHIFT;
2496 * Factor in the task's own contribution to the overage, such that four
2497 * N-sized allocations are throttled approximately the same as one
2498 * 4N-sized allocation.
2500 * MEMCG_CHARGE_BATCH pages is nominal, so work out how much smaller or
2501 * larger the current charge patch is than that.
2503 return penalty_jiffies * nr_pages / MEMCG_CHARGE_BATCH;
2507 * Scheduled by try_charge() to be executed from the userland return path
2508 * and reclaims memory over the high limit.
2510 void mem_cgroup_handle_over_high(void)
2512 unsigned long penalty_jiffies;
2513 unsigned long pflags;
2514 unsigned long nr_reclaimed;
2515 unsigned int nr_pages = current->memcg_nr_pages_over_high;
2516 int nr_retries = MAX_RECLAIM_RETRIES;
2517 struct mem_cgroup *memcg;
2518 bool in_retry = false;
2520 if (likely(!nr_pages))
2523 memcg = get_mem_cgroup_from_mm(current->mm);
2524 current->memcg_nr_pages_over_high = 0;
2528 * The allocating task should reclaim at least the batch size, but for
2529 * subsequent retries we only want to do what's necessary to prevent oom
2530 * or breaching resource isolation.
2532 * This is distinct from memory.max or page allocator behaviour because
2533 * memory.high is currently batched, whereas memory.max and the page
2534 * allocator run every time an allocation is made.
2536 nr_reclaimed = reclaim_high(memcg,
2537 in_retry ? SWAP_CLUSTER_MAX : nr_pages,
2541 * memory.high is breached and reclaim is unable to keep up. Throttle
2542 * allocators proactively to slow down excessive growth.
2544 penalty_jiffies = calculate_high_delay(memcg, nr_pages,
2545 mem_find_max_overage(memcg));
2547 penalty_jiffies += calculate_high_delay(memcg, nr_pages,
2548 swap_find_max_overage(memcg));
2551 * Clamp the max delay per usermode return so as to still keep the
2552 * application moving forwards and also permit diagnostics, albeit
2555 penalty_jiffies = min(penalty_jiffies, MEMCG_MAX_HIGH_DELAY_JIFFIES);
2558 * Don't sleep if the amount of jiffies this memcg owes us is so low
2559 * that it's not even worth doing, in an attempt to be nice to those who
2560 * go only a small amount over their memory.high value and maybe haven't
2561 * been aggressively reclaimed enough yet.
2563 if (penalty_jiffies <= HZ / 100)
2567 * If reclaim is making forward progress but we're still over
2568 * memory.high, we want to encourage that rather than doing allocator
2571 if (nr_reclaimed || nr_retries--) {
2577 * If we exit early, we're guaranteed to die (since
2578 * schedule_timeout_killable sets TASK_KILLABLE). This means we don't
2579 * need to account for any ill-begotten jiffies to pay them off later.
2581 psi_memstall_enter(&pflags);
2582 schedule_timeout_killable(penalty_jiffies);
2583 psi_memstall_leave(&pflags);
2586 css_put(&memcg->css);
2589 static int try_charge_memcg(struct mem_cgroup *memcg, gfp_t gfp_mask,
2590 unsigned int nr_pages)
2592 unsigned int batch = max(MEMCG_CHARGE_BATCH, nr_pages);
2593 int nr_retries = MAX_RECLAIM_RETRIES;
2594 struct mem_cgroup *mem_over_limit;
2595 struct page_counter *counter;
2596 enum oom_status oom_status;
2597 unsigned long nr_reclaimed;
2598 bool passed_oom = false;
2599 bool may_swap = true;
2600 bool drained = false;
2601 unsigned long pflags;
2604 if (consume_stock(memcg, nr_pages))
2607 if (!do_memsw_account() ||
2608 page_counter_try_charge(&memcg->memsw, batch, &counter)) {
2609 if (page_counter_try_charge(&memcg->memory, batch, &counter))
2611 if (do_memsw_account())
2612 page_counter_uncharge(&memcg->memsw, batch);
2613 mem_over_limit = mem_cgroup_from_counter(counter, memory);
2615 mem_over_limit = mem_cgroup_from_counter(counter, memsw);
2619 if (batch > nr_pages) {
2625 * Memcg doesn't have a dedicated reserve for atomic
2626 * allocations. But like the global atomic pool, we need to
2627 * put the burden of reclaim on regular allocation requests
2628 * and let these go through as privileged allocations.
2630 if (gfp_mask & __GFP_ATOMIC)
2634 * Prevent unbounded recursion when reclaim operations need to
2635 * allocate memory. This might exceed the limits temporarily,
2636 * but we prefer facilitating memory reclaim and getting back
2637 * under the limit over triggering OOM kills in these cases.
2639 if (unlikely(current->flags & PF_MEMALLOC))
2642 if (unlikely(task_in_memcg_oom(current)))
2645 if (!gfpflags_allow_blocking(gfp_mask))
2648 memcg_memory_event(mem_over_limit, MEMCG_MAX);
2650 psi_memstall_enter(&pflags);
2651 nr_reclaimed = try_to_free_mem_cgroup_pages(mem_over_limit, nr_pages,
2652 gfp_mask, may_swap);
2653 psi_memstall_leave(&pflags);
2655 if (mem_cgroup_margin(mem_over_limit) >= nr_pages)
2659 drain_all_stock(mem_over_limit);
2664 if (gfp_mask & __GFP_NORETRY)
2667 * Even though the limit is exceeded at this point, reclaim
2668 * may have been able to free some pages. Retry the charge
2669 * before killing the task.
2671 * Only for regular pages, though: huge pages are rather
2672 * unlikely to succeed so close to the limit, and we fall back
2673 * to regular pages anyway in case of failure.
2675 if (nr_reclaimed && nr_pages <= (1 << PAGE_ALLOC_COSTLY_ORDER))
2678 * At task move, charge accounts can be doubly counted. So, it's
2679 * better to wait until the end of task_move if something is going on.
2681 if (mem_cgroup_wait_acct_move(mem_over_limit))
2687 if (gfp_mask & __GFP_RETRY_MAYFAIL)
2690 /* Avoid endless loop for tasks bypassed by the oom killer */
2691 if (passed_oom && task_is_dying())
2695 * keep retrying as long as the memcg oom killer is able to make
2696 * a forward progress or bypass the charge if the oom killer
2697 * couldn't make any progress.
2699 oom_status = mem_cgroup_oom(mem_over_limit, gfp_mask,
2700 get_order(nr_pages * PAGE_SIZE));
2701 if (oom_status == OOM_SUCCESS) {
2703 nr_retries = MAX_RECLAIM_RETRIES;
2707 if (!(gfp_mask & __GFP_NOFAIL))
2711 * The allocation either can't fail or will lead to more memory
2712 * being freed very soon. Allow memory usage go over the limit
2713 * temporarily by force charging it.
2715 page_counter_charge(&memcg->memory, nr_pages);
2716 if (do_memsw_account())
2717 page_counter_charge(&memcg->memsw, nr_pages);
2722 if (batch > nr_pages)
2723 refill_stock(memcg, batch - nr_pages);
2726 * If the hierarchy is above the normal consumption range, schedule
2727 * reclaim on returning to userland. We can perform reclaim here
2728 * if __GFP_RECLAIM but let's always punt for simplicity and so that
2729 * GFP_KERNEL can consistently be used during reclaim. @memcg is
2730 * not recorded as it most likely matches current's and won't
2731 * change in the meantime. As high limit is checked again before
2732 * reclaim, the cost of mismatch is negligible.
2735 bool mem_high, swap_high;
2737 mem_high = page_counter_read(&memcg->memory) >
2738 READ_ONCE(memcg->memory.high);
2739 swap_high = page_counter_read(&memcg->swap) >
2740 READ_ONCE(memcg->swap.high);
2742 /* Don't bother a random interrupted task */
2743 if (in_interrupt()) {
2745 schedule_work(&memcg->high_work);
2751 if (mem_high || swap_high) {
2753 * The allocating tasks in this cgroup will need to do
2754 * reclaim or be throttled to prevent further growth
2755 * of the memory or swap footprints.
2757 * Target some best-effort fairness between the tasks,
2758 * and distribute reclaim work and delay penalties
2759 * based on how much each task is actually allocating.
2761 current->memcg_nr_pages_over_high += batch;
2762 set_notify_resume(current);
2765 } while ((memcg = parent_mem_cgroup(memcg)));
2770 static inline int try_charge(struct mem_cgroup *memcg, gfp_t gfp_mask,
2771 unsigned int nr_pages)
2773 if (mem_cgroup_is_root(memcg))
2776 return try_charge_memcg(memcg, gfp_mask, nr_pages);
2779 #if defined(CONFIG_MEMCG_KMEM) || defined(CONFIG_MMU)
2780 static void cancel_charge(struct mem_cgroup *memcg, unsigned int nr_pages)
2782 if (mem_cgroup_is_root(memcg))
2785 page_counter_uncharge(&memcg->memory, nr_pages);
2786 if (do_memsw_account())
2787 page_counter_uncharge(&memcg->memsw, nr_pages);
2791 static void commit_charge(struct page *page, struct mem_cgroup *memcg)
2793 VM_BUG_ON_PAGE(page_memcg(page), page);
2795 * Any of the following ensures page's memcg stability:
2799 * - lock_page_memcg()
2800 * - exclusive reference
2802 page->memcg_data = (unsigned long)memcg;
2805 static struct mem_cgroup *get_mem_cgroup_from_objcg(struct obj_cgroup *objcg)
2807 struct mem_cgroup *memcg;
2811 memcg = obj_cgroup_memcg(objcg);
2812 if (unlikely(!css_tryget(&memcg->css)))
2819 #ifdef CONFIG_MEMCG_KMEM
2821 * The allocated objcg pointers array is not accounted directly.
2822 * Moreover, it should not come from DMA buffer and is not readily
2823 * reclaimable. So those GFP bits should be masked off.
2825 #define OBJCGS_CLEAR_MASK (__GFP_DMA | __GFP_RECLAIMABLE | __GFP_ACCOUNT)
2827 int memcg_alloc_page_obj_cgroups(struct page *page, struct kmem_cache *s,
2828 gfp_t gfp, bool new_page)
2830 unsigned int objects = objs_per_slab_page(s, page);
2831 unsigned long memcg_data;
2834 gfp &= ~OBJCGS_CLEAR_MASK;
2835 vec = kcalloc_node(objects, sizeof(struct obj_cgroup *), gfp,
2840 memcg_data = (unsigned long) vec | MEMCG_DATA_OBJCGS;
2843 * If the slab page is brand new and nobody can yet access
2844 * it's memcg_data, no synchronization is required and
2845 * memcg_data can be simply assigned.
2847 page->memcg_data = memcg_data;
2848 } else if (cmpxchg(&page->memcg_data, 0, memcg_data)) {
2850 * If the slab page is already in use, somebody can allocate
2851 * and assign obj_cgroups in parallel. In this case the existing
2852 * objcg vector should be reused.
2858 kmemleak_not_leak(vec);
2863 * Returns a pointer to the memory cgroup to which the kernel object is charged.
2865 * A passed kernel object can be a slab object or a generic kernel page, so
2866 * different mechanisms for getting the memory cgroup pointer should be used.
2867 * In certain cases (e.g. kernel stacks or large kmallocs with SLUB) the caller
2868 * can not know for sure how the kernel object is implemented.
2869 * mem_cgroup_from_obj() can be safely used in such cases.
2871 * The caller must ensure the memcg lifetime, e.g. by taking rcu_read_lock(),
2872 * cgroup_mutex, etc.
2874 struct mem_cgroup *mem_cgroup_from_obj(void *p)
2878 if (mem_cgroup_disabled())
2881 page = virt_to_head_page(p);
2884 * Slab objects are accounted individually, not per-page.
2885 * Memcg membership data for each individual object is saved in
2886 * the page->obj_cgroups.
2888 if (page_objcgs_check(page)) {
2889 struct obj_cgroup *objcg;
2892 off = obj_to_index(page->slab_cache, page, p);
2893 objcg = page_objcgs(page)[off];
2895 return obj_cgroup_memcg(objcg);
2901 * page_memcg_check() is used here, because page_has_obj_cgroups()
2902 * check above could fail because the object cgroups vector wasn't set
2903 * at that moment, but it can be set concurrently.
2904 * page_memcg_check(page) will guarantee that a proper memory
2905 * cgroup pointer or NULL will be returned.
2907 return page_memcg_check(page);
2910 __always_inline struct obj_cgroup *get_obj_cgroup_from_current(void)
2912 struct obj_cgroup *objcg = NULL;
2913 struct mem_cgroup *memcg;
2915 if (memcg_kmem_bypass())
2919 if (unlikely(active_memcg()))
2920 memcg = active_memcg();
2922 memcg = mem_cgroup_from_task(current);
2924 for (; memcg != root_mem_cgroup; memcg = parent_mem_cgroup(memcg)) {
2925 objcg = rcu_dereference(memcg->objcg);
2926 if (objcg && obj_cgroup_tryget(objcg))
2935 static int memcg_alloc_cache_id(void)
2940 id = ida_simple_get(&memcg_cache_ida,
2941 0, MEMCG_CACHES_MAX_SIZE, GFP_KERNEL);
2945 if (id < memcg_nr_cache_ids)
2949 * There's no space for the new id in memcg_caches arrays,
2950 * so we have to grow them.
2952 down_write(&memcg_cache_ids_sem);
2954 size = 2 * (id + 1);
2955 if (size < MEMCG_CACHES_MIN_SIZE)
2956 size = MEMCG_CACHES_MIN_SIZE;
2957 else if (size > MEMCG_CACHES_MAX_SIZE)
2958 size = MEMCG_CACHES_MAX_SIZE;
2960 err = memcg_update_all_list_lrus(size);
2962 memcg_nr_cache_ids = size;
2964 up_write(&memcg_cache_ids_sem);
2967 ida_simple_remove(&memcg_cache_ida, id);
2973 static void memcg_free_cache_id(int id)
2975 ida_simple_remove(&memcg_cache_ida, id);
2979 * obj_cgroup_uncharge_pages: uncharge a number of kernel pages from a objcg
2980 * @objcg: object cgroup to uncharge
2981 * @nr_pages: number of pages to uncharge
2983 static void obj_cgroup_uncharge_pages(struct obj_cgroup *objcg,
2984 unsigned int nr_pages)
2986 struct mem_cgroup *memcg;
2988 memcg = get_mem_cgroup_from_objcg(objcg);
2990 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys))
2991 page_counter_uncharge(&memcg->kmem, nr_pages);
2992 refill_stock(memcg, nr_pages);
2994 css_put(&memcg->css);
2998 * obj_cgroup_charge_pages: charge a number of kernel pages to a objcg
2999 * @objcg: object cgroup to charge
3000 * @gfp: reclaim mode
3001 * @nr_pages: number of pages to charge
3003 * Returns 0 on success, an error code on failure.
3005 static int obj_cgroup_charge_pages(struct obj_cgroup *objcg, gfp_t gfp,
3006 unsigned int nr_pages)
3008 struct page_counter *counter;
3009 struct mem_cgroup *memcg;
3012 memcg = get_mem_cgroup_from_objcg(objcg);
3014 ret = try_charge_memcg(memcg, gfp, nr_pages);
3018 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) &&
3019 !page_counter_try_charge(&memcg->kmem, nr_pages, &counter)) {
3022 * Enforce __GFP_NOFAIL allocation because callers are not
3023 * prepared to see failures and likely do not have any failure
3026 if (gfp & __GFP_NOFAIL) {
3027 page_counter_charge(&memcg->kmem, nr_pages);
3030 cancel_charge(memcg, nr_pages);
3034 css_put(&memcg->css);
3040 * __memcg_kmem_charge_page: charge a kmem page to the current memory cgroup
3041 * @page: page to charge
3042 * @gfp: reclaim mode
3043 * @order: allocation order
3045 * Returns 0 on success, an error code on failure.
3047 int __memcg_kmem_charge_page(struct page *page, gfp_t gfp, int order)
3049 struct obj_cgroup *objcg;
3052 objcg = get_obj_cgroup_from_current();
3054 ret = obj_cgroup_charge_pages(objcg, gfp, 1 << order);
3056 page->memcg_data = (unsigned long)objcg |
3060 obj_cgroup_put(objcg);
3066 * __memcg_kmem_uncharge_page: uncharge a kmem page
3067 * @page: page to uncharge
3068 * @order: allocation order
3070 void __memcg_kmem_uncharge_page(struct page *page, int order)
3072 struct obj_cgroup *objcg;
3073 unsigned int nr_pages = 1 << order;
3075 if (!PageMemcgKmem(page))
3078 objcg = __page_objcg(page);
3079 obj_cgroup_uncharge_pages(objcg, nr_pages);
3080 page->memcg_data = 0;
3081 obj_cgroup_put(objcg);
3084 void mod_objcg_state(struct obj_cgroup *objcg, struct pglist_data *pgdat,
3085 enum node_stat_item idx, int nr)
3087 unsigned long flags;
3088 struct obj_stock *stock = get_obj_stock(&flags);
3092 * Save vmstat data in stock and skip vmstat array update unless
3093 * accumulating over a page of vmstat data or when pgdat or idx
3096 if (stock->cached_objcg != objcg) {
3097 drain_obj_stock(stock);
3098 obj_cgroup_get(objcg);
3099 stock->nr_bytes = atomic_read(&objcg->nr_charged_bytes)
3100 ? atomic_xchg(&objcg->nr_charged_bytes, 0) : 0;
3101 stock->cached_objcg = objcg;
3102 stock->cached_pgdat = pgdat;
3103 } else if (stock->cached_pgdat != pgdat) {
3104 /* Flush the existing cached vmstat data */
3105 struct pglist_data *oldpg = stock->cached_pgdat;
3107 if (stock->nr_slab_reclaimable_b) {
3108 mod_objcg_mlstate(objcg, oldpg, NR_SLAB_RECLAIMABLE_B,
3109 stock->nr_slab_reclaimable_b);
3110 stock->nr_slab_reclaimable_b = 0;
3112 if (stock->nr_slab_unreclaimable_b) {
3113 mod_objcg_mlstate(objcg, oldpg, NR_SLAB_UNRECLAIMABLE_B,
3114 stock->nr_slab_unreclaimable_b);
3115 stock->nr_slab_unreclaimable_b = 0;
3117 stock->cached_pgdat = pgdat;
3120 bytes = (idx == NR_SLAB_RECLAIMABLE_B) ? &stock->nr_slab_reclaimable_b
3121 : &stock->nr_slab_unreclaimable_b;
3123 * Even for large object >= PAGE_SIZE, the vmstat data will still be
3124 * cached locally at least once before pushing it out.
3131 if (abs(*bytes) > PAGE_SIZE) {
3139 mod_objcg_mlstate(objcg, pgdat, idx, nr);
3141 put_obj_stock(flags);
3144 static bool consume_obj_stock(struct obj_cgroup *objcg, unsigned int nr_bytes)
3146 unsigned long flags;
3147 struct obj_stock *stock = get_obj_stock(&flags);
3150 if (objcg == stock->cached_objcg && stock->nr_bytes >= nr_bytes) {
3151 stock->nr_bytes -= nr_bytes;
3155 put_obj_stock(flags);
3160 static void drain_obj_stock(struct obj_stock *stock)
3162 struct obj_cgroup *old = stock->cached_objcg;
3167 if (stock->nr_bytes) {
3168 unsigned int nr_pages = stock->nr_bytes >> PAGE_SHIFT;
3169 unsigned int nr_bytes = stock->nr_bytes & (PAGE_SIZE - 1);
3172 obj_cgroup_uncharge_pages(old, nr_pages);
3175 * The leftover is flushed to the centralized per-memcg value.
3176 * On the next attempt to refill obj stock it will be moved
3177 * to a per-cpu stock (probably, on an other CPU), see
3178 * refill_obj_stock().
3180 * How often it's flushed is a trade-off between the memory
3181 * limit enforcement accuracy and potential CPU contention,
3182 * so it might be changed in the future.
3184 atomic_add(nr_bytes, &old->nr_charged_bytes);
3185 stock->nr_bytes = 0;
3189 * Flush the vmstat data in current stock
3191 if (stock->nr_slab_reclaimable_b || stock->nr_slab_unreclaimable_b) {
3192 if (stock->nr_slab_reclaimable_b) {
3193 mod_objcg_mlstate(old, stock->cached_pgdat,
3194 NR_SLAB_RECLAIMABLE_B,
3195 stock->nr_slab_reclaimable_b);
3196 stock->nr_slab_reclaimable_b = 0;
3198 if (stock->nr_slab_unreclaimable_b) {
3199 mod_objcg_mlstate(old, stock->cached_pgdat,
3200 NR_SLAB_UNRECLAIMABLE_B,
3201 stock->nr_slab_unreclaimable_b);
3202 stock->nr_slab_unreclaimable_b = 0;
3204 stock->cached_pgdat = NULL;
3207 obj_cgroup_put(old);
3208 stock->cached_objcg = NULL;
3211 static bool obj_stock_flush_required(struct memcg_stock_pcp *stock,
3212 struct mem_cgroup *root_memcg)
3214 struct mem_cgroup *memcg;
3216 if (in_task() && stock->task_obj.cached_objcg) {
3217 memcg = obj_cgroup_memcg(stock->task_obj.cached_objcg);
3218 if (memcg && mem_cgroup_is_descendant(memcg, root_memcg))
3221 if (stock->irq_obj.cached_objcg) {
3222 memcg = obj_cgroup_memcg(stock->irq_obj.cached_objcg);
3223 if (memcg && mem_cgroup_is_descendant(memcg, root_memcg))
3230 static void refill_obj_stock(struct obj_cgroup *objcg, unsigned int nr_bytes,
3231 bool allow_uncharge)
3233 unsigned long flags;
3234 struct obj_stock *stock = get_obj_stock(&flags);
3235 unsigned int nr_pages = 0;
3237 if (stock->cached_objcg != objcg) { /* reset if necessary */
3238 drain_obj_stock(stock);
3239 obj_cgroup_get(objcg);
3240 stock->cached_objcg = objcg;
3241 stock->nr_bytes = atomic_read(&objcg->nr_charged_bytes)
3242 ? atomic_xchg(&objcg->nr_charged_bytes, 0) : 0;
3243 allow_uncharge = true; /* Allow uncharge when objcg changes */
3245 stock->nr_bytes += nr_bytes;
3247 if (allow_uncharge && (stock->nr_bytes > PAGE_SIZE)) {
3248 nr_pages = stock->nr_bytes >> PAGE_SHIFT;
3249 stock->nr_bytes &= (PAGE_SIZE - 1);
3252 put_obj_stock(flags);
3255 obj_cgroup_uncharge_pages(objcg, nr_pages);
3258 int obj_cgroup_charge(struct obj_cgroup *objcg, gfp_t gfp, size_t size)
3260 unsigned int nr_pages, nr_bytes;
3263 if (consume_obj_stock(objcg, size))
3267 * In theory, objcg->nr_charged_bytes can have enough
3268 * pre-charged bytes to satisfy the allocation. However,
3269 * flushing objcg->nr_charged_bytes requires two atomic
3270 * operations, and objcg->nr_charged_bytes can't be big.
3271 * The shared objcg->nr_charged_bytes can also become a
3272 * performance bottleneck if all tasks of the same memcg are
3273 * trying to update it. So it's better to ignore it and try
3274 * grab some new pages. The stock's nr_bytes will be flushed to
3275 * objcg->nr_charged_bytes later on when objcg changes.
3277 * The stock's nr_bytes may contain enough pre-charged bytes
3278 * to allow one less page from being charged, but we can't rely
3279 * on the pre-charged bytes not being changed outside of
3280 * consume_obj_stock() or refill_obj_stock(). So ignore those
3281 * pre-charged bytes as well when charging pages. To avoid a
3282 * page uncharge right after a page charge, we set the
3283 * allow_uncharge flag to false when calling refill_obj_stock()
3284 * to temporarily allow the pre-charged bytes to exceed the page
3285 * size limit. The maximum reachable value of the pre-charged
3286 * bytes is (sizeof(object) + PAGE_SIZE - 2) if there is no data
3289 nr_pages = size >> PAGE_SHIFT;
3290 nr_bytes = size & (PAGE_SIZE - 1);
3295 ret = obj_cgroup_charge_pages(objcg, gfp, nr_pages);
3296 if (!ret && nr_bytes)
3297 refill_obj_stock(objcg, PAGE_SIZE - nr_bytes, false);
3302 void obj_cgroup_uncharge(struct obj_cgroup *objcg, size_t size)
3304 refill_obj_stock(objcg, size, true);
3307 #endif /* CONFIG_MEMCG_KMEM */
3310 * Because page_memcg(head) is not set on tails, set it now.
3312 void split_page_memcg(struct page *head, unsigned int nr)
3314 struct mem_cgroup *memcg = page_memcg(head);
3317 if (mem_cgroup_disabled() || !memcg)
3320 for (i = 1; i < nr; i++)
3321 head[i].memcg_data = head->memcg_data;
3323 if (PageMemcgKmem(head))
3324 obj_cgroup_get_many(__page_objcg(head), nr - 1);
3326 css_get_many(&memcg->css, nr - 1);
3329 #ifdef CONFIG_MEMCG_SWAP
3331 * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record.
3332 * @entry: swap entry to be moved
3333 * @from: mem_cgroup which the entry is moved from
3334 * @to: mem_cgroup which the entry is moved to
3336 * It succeeds only when the swap_cgroup's record for this entry is the same
3337 * as the mem_cgroup's id of @from.
3339 * Returns 0 on success, -EINVAL on failure.
3341 * The caller must have charged to @to, IOW, called page_counter_charge() about
3342 * both res and memsw, and called css_get().
3344 static int mem_cgroup_move_swap_account(swp_entry_t entry,
3345 struct mem_cgroup *from, struct mem_cgroup *to)
3347 unsigned short old_id, new_id;
3349 old_id = mem_cgroup_id(from);
3350 new_id = mem_cgroup_id(to);
3352 if (swap_cgroup_cmpxchg(entry, old_id, new_id) == old_id) {
3353 mod_memcg_state(from, MEMCG_SWAP, -1);
3354 mod_memcg_state(to, MEMCG_SWAP, 1);
3360 static inline int mem_cgroup_move_swap_account(swp_entry_t entry,
3361 struct mem_cgroup *from, struct mem_cgroup *to)
3367 static DEFINE_MUTEX(memcg_max_mutex);
3369 static int mem_cgroup_resize_max(struct mem_cgroup *memcg,
3370 unsigned long max, bool memsw)
3372 bool enlarge = false;
3373 bool drained = false;
3375 bool limits_invariant;
3376 struct page_counter *counter = memsw ? &memcg->memsw : &memcg->memory;
3379 if (signal_pending(current)) {
3384 mutex_lock(&memcg_max_mutex);
3386 * Make sure that the new limit (memsw or memory limit) doesn't
3387 * break our basic invariant rule memory.max <= memsw.max.
3389 limits_invariant = memsw ? max >= READ_ONCE(memcg->memory.max) :
3390 max <= memcg->memsw.max;
3391 if (!limits_invariant) {
3392 mutex_unlock(&memcg_max_mutex);
3396 if (max > counter->max)
3398 ret = page_counter_set_max(counter, max);
3399 mutex_unlock(&memcg_max_mutex);
3405 drain_all_stock(memcg);
3410 if (!try_to_free_mem_cgroup_pages(memcg, 1,
3411 GFP_KERNEL, !memsw)) {
3417 if (!ret && enlarge)
3418 memcg_oom_recover(memcg);
3423 unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order,
3425 unsigned long *total_scanned)
3427 unsigned long nr_reclaimed = 0;
3428 struct mem_cgroup_per_node *mz, *next_mz = NULL;
3429 unsigned long reclaimed;
3431 struct mem_cgroup_tree_per_node *mctz;
3432 unsigned long excess;
3433 unsigned long nr_scanned;
3438 mctz = soft_limit_tree_node(pgdat->node_id);
3441 * Do not even bother to check the largest node if the root
3442 * is empty. Do it lockless to prevent lock bouncing. Races
3443 * are acceptable as soft limit is best effort anyway.
3445 if (!mctz || RB_EMPTY_ROOT(&mctz->rb_root))
3449 * This loop can run a while, specially if mem_cgroup's continuously
3450 * keep exceeding their soft limit and putting the system under
3457 mz = mem_cgroup_largest_soft_limit_node(mctz);
3462 reclaimed = mem_cgroup_soft_reclaim(mz->memcg, pgdat,
3463 gfp_mask, &nr_scanned);
3464 nr_reclaimed += reclaimed;
3465 *total_scanned += nr_scanned;
3466 spin_lock_irq(&mctz->lock);
3467 __mem_cgroup_remove_exceeded(mz, mctz);
3470 * If we failed to reclaim anything from this memory cgroup
3471 * it is time to move on to the next cgroup
3475 next_mz = __mem_cgroup_largest_soft_limit_node(mctz);
3477 excess = soft_limit_excess(mz->memcg);
3479 * One school of thought says that we should not add
3480 * back the node to the tree if reclaim returns 0.
3481 * But our reclaim could return 0, simply because due
3482 * to priority we are exposing a smaller subset of
3483 * memory to reclaim from. Consider this as a longer
3486 /* If excess == 0, no tree ops */
3487 __mem_cgroup_insert_exceeded(mz, mctz, excess);
3488 spin_unlock_irq(&mctz->lock);
3489 css_put(&mz->memcg->css);
3492 * Could not reclaim anything and there are no more
3493 * mem cgroups to try or we seem to be looping without
3494 * reclaiming anything.
3496 if (!nr_reclaimed &&
3498 loop > MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS))
3500 } while (!nr_reclaimed);
3502 css_put(&next_mz->memcg->css);
3503 return nr_reclaimed;
3507 * Reclaims as many pages from the given memcg as possible.
3509 * Caller is responsible for holding css reference for memcg.
3511 static int mem_cgroup_force_empty(struct mem_cgroup *memcg)
3513 int nr_retries = MAX_RECLAIM_RETRIES;
3515 /* we call try-to-free pages for make this cgroup empty */
3516 lru_add_drain_all();
3518 drain_all_stock(memcg);
3520 /* try to free all pages in this cgroup */
3521 while (nr_retries && page_counter_read(&memcg->memory)) {
3524 if (signal_pending(current))
3527 progress = try_to_free_mem_cgroup_pages(memcg, 1,
3531 /* maybe some writeback is necessary */
3532 congestion_wait(BLK_RW_ASYNC, HZ/10);
3540 static ssize_t mem_cgroup_force_empty_write(struct kernfs_open_file *of,
3541 char *buf, size_t nbytes,
3544 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
3546 if (mem_cgroup_is_root(memcg))
3548 return mem_cgroup_force_empty(memcg) ?: nbytes;
3551 static u64 mem_cgroup_hierarchy_read(struct cgroup_subsys_state *css,
3557 static int mem_cgroup_hierarchy_write(struct cgroup_subsys_state *css,
3558 struct cftype *cft, u64 val)
3563 pr_warn_once("Non-hierarchical mode is deprecated. "
3564 "Please report your usecase to linux-mm@kvack.org if you "
3565 "depend on this functionality.\n");
3570 static unsigned long mem_cgroup_usage(struct mem_cgroup *memcg, bool swap)
3574 if (mem_cgroup_is_root(memcg)) {
3575 mem_cgroup_flush_stats();
3576 val = memcg_page_state(memcg, NR_FILE_PAGES) +
3577 memcg_page_state(memcg, NR_ANON_MAPPED);
3579 val += memcg_page_state(memcg, MEMCG_SWAP);
3582 val = page_counter_read(&memcg->memory);
3584 val = page_counter_read(&memcg->memsw);
3597 static u64 mem_cgroup_read_u64(struct cgroup_subsys_state *css,
3600 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
3601 struct page_counter *counter;
3603 switch (MEMFILE_TYPE(cft->private)) {
3605 counter = &memcg->memory;
3608 counter = &memcg->memsw;
3611 counter = &memcg->kmem;
3614 counter = &memcg->tcpmem;
3620 switch (MEMFILE_ATTR(cft->private)) {
3622 if (counter == &memcg->memory)
3623 return (u64)mem_cgroup_usage(memcg, false) * PAGE_SIZE;
3624 if (counter == &memcg->memsw)
3625 return (u64)mem_cgroup_usage(memcg, true) * PAGE_SIZE;
3626 return (u64)page_counter_read(counter) * PAGE_SIZE;
3628 return (u64)counter->max * PAGE_SIZE;
3630 return (u64)counter->watermark * PAGE_SIZE;
3632 return counter->failcnt;
3633 case RES_SOFT_LIMIT:
3634 return (u64)memcg->soft_limit * PAGE_SIZE;
3640 #ifdef CONFIG_MEMCG_KMEM
3641 static int memcg_online_kmem(struct mem_cgroup *memcg)
3643 struct obj_cgroup *objcg;
3646 if (cgroup_memory_nokmem)
3649 BUG_ON(memcg->kmemcg_id >= 0);
3650 BUG_ON(memcg->kmem_state);
3652 memcg_id = memcg_alloc_cache_id();
3656 objcg = obj_cgroup_alloc();
3658 memcg_free_cache_id(memcg_id);
3661 objcg->memcg = memcg;
3662 rcu_assign_pointer(memcg->objcg, objcg);
3664 static_branch_enable(&memcg_kmem_enabled_key);
3666 memcg->kmemcg_id = memcg_id;
3667 memcg->kmem_state = KMEM_ONLINE;
3672 static void memcg_offline_kmem(struct mem_cgroup *memcg)
3674 struct cgroup_subsys_state *css;
3675 struct mem_cgroup *parent, *child;
3678 if (memcg->kmem_state != KMEM_ONLINE)
3681 memcg->kmem_state = KMEM_ALLOCATED;
3683 parent = parent_mem_cgroup(memcg);
3685 parent = root_mem_cgroup;
3687 memcg_reparent_objcgs(memcg, parent);
3689 kmemcg_id = memcg->kmemcg_id;
3690 BUG_ON(kmemcg_id < 0);
3693 * Change kmemcg_id of this cgroup and all its descendants to the
3694 * parent's id, and then move all entries from this cgroup's list_lrus
3695 * to ones of the parent. After we have finished, all list_lrus
3696 * corresponding to this cgroup are guaranteed to remain empty. The
3697 * ordering is imposed by list_lru_node->lock taken by
3698 * memcg_drain_all_list_lrus().
3700 rcu_read_lock(); /* can be called from css_free w/o cgroup_mutex */
3701 css_for_each_descendant_pre(css, &memcg->css) {
3702 child = mem_cgroup_from_css(css);
3703 BUG_ON(child->kmemcg_id != kmemcg_id);
3704 child->kmemcg_id = parent->kmemcg_id;
3708 memcg_drain_all_list_lrus(kmemcg_id, parent);
3710 memcg_free_cache_id(kmemcg_id);
3713 static void memcg_free_kmem(struct mem_cgroup *memcg)
3715 /* css_alloc() failed, offlining didn't happen */
3716 if (unlikely(memcg->kmem_state == KMEM_ONLINE))
3717 memcg_offline_kmem(memcg);
3720 static int memcg_online_kmem(struct mem_cgroup *memcg)
3724 static void memcg_offline_kmem(struct mem_cgroup *memcg)
3727 static void memcg_free_kmem(struct mem_cgroup *memcg)
3730 #endif /* CONFIG_MEMCG_KMEM */
3732 static int memcg_update_kmem_max(struct mem_cgroup *memcg,
3737 mutex_lock(&memcg_max_mutex);
3738 ret = page_counter_set_max(&memcg->kmem, max);
3739 mutex_unlock(&memcg_max_mutex);
3743 static int memcg_update_tcp_max(struct mem_cgroup *memcg, unsigned long max)
3747 mutex_lock(&memcg_max_mutex);
3749 ret = page_counter_set_max(&memcg->tcpmem, max);
3753 if (!memcg->tcpmem_active) {
3755 * The active flag needs to be written after the static_key
3756 * update. This is what guarantees that the socket activation
3757 * function is the last one to run. See mem_cgroup_sk_alloc()
3758 * for details, and note that we don't mark any socket as
3759 * belonging to this memcg until that flag is up.
3761 * We need to do this, because static_keys will span multiple
3762 * sites, but we can't control their order. If we mark a socket
3763 * as accounted, but the accounting functions are not patched in
3764 * yet, we'll lose accounting.
3766 * We never race with the readers in mem_cgroup_sk_alloc(),
3767 * because when this value change, the code to process it is not
3770 static_branch_inc(&memcg_sockets_enabled_key);
3771 memcg->tcpmem_active = true;
3774 mutex_unlock(&memcg_max_mutex);
3779 * The user of this function is...
3782 static ssize_t mem_cgroup_write(struct kernfs_open_file *of,
3783 char *buf, size_t nbytes, loff_t off)
3785 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
3786 unsigned long nr_pages;
3789 buf = strstrip(buf);
3790 ret = page_counter_memparse(buf, "-1", &nr_pages);
3794 switch (MEMFILE_ATTR(of_cft(of)->private)) {
3796 if (mem_cgroup_is_root(memcg)) { /* Can't set limit on root */
3800 switch (MEMFILE_TYPE(of_cft(of)->private)) {
3802 ret = mem_cgroup_resize_max(memcg, nr_pages, false);
3805 ret = mem_cgroup_resize_max(memcg, nr_pages, true);
3808 pr_warn_once("kmem.limit_in_bytes is deprecated and will be removed. "
3809 "Please report your usecase to linux-mm@kvack.org if you "
3810 "depend on this functionality.\n");
3811 ret = memcg_update_kmem_max(memcg, nr_pages);
3814 ret = memcg_update_tcp_max(memcg, nr_pages);
3818 case RES_SOFT_LIMIT:
3819 memcg->soft_limit = nr_pages;
3823 return ret ?: nbytes;
3826 static ssize_t mem_cgroup_reset(struct kernfs_open_file *of, char *buf,
3827 size_t nbytes, loff_t off)
3829 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
3830 struct page_counter *counter;
3832 switch (MEMFILE_TYPE(of_cft(of)->private)) {
3834 counter = &memcg->memory;
3837 counter = &memcg->memsw;
3840 counter = &memcg->kmem;
3843 counter = &memcg->tcpmem;
3849 switch (MEMFILE_ATTR(of_cft(of)->private)) {
3851 page_counter_reset_watermark(counter);
3854 counter->failcnt = 0;
3863 static u64 mem_cgroup_move_charge_read(struct cgroup_subsys_state *css,
3866 return mem_cgroup_from_css(css)->move_charge_at_immigrate;
3870 static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css,
3871 struct cftype *cft, u64 val)
3873 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
3875 if (val & ~MOVE_MASK)
3879 * No kind of locking is needed in here, because ->can_attach() will
3880 * check this value once in the beginning of the process, and then carry
3881 * on with stale data. This means that changes to this value will only
3882 * affect task migrations starting after the change.
3884 memcg->move_charge_at_immigrate = val;
3888 static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css,
3889 struct cftype *cft, u64 val)
3897 #define LRU_ALL_FILE (BIT(LRU_INACTIVE_FILE) | BIT(LRU_ACTIVE_FILE))
3898 #define LRU_ALL_ANON (BIT(LRU_INACTIVE_ANON) | BIT(LRU_ACTIVE_ANON))
3899 #define LRU_ALL ((1 << NR_LRU_LISTS) - 1)
3901 static unsigned long mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg,
3902 int nid, unsigned int lru_mask, bool tree)
3904 struct lruvec *lruvec = mem_cgroup_lruvec(memcg, NODE_DATA(nid));
3905 unsigned long nr = 0;
3908 VM_BUG_ON((unsigned)nid >= nr_node_ids);
3911 if (!(BIT(lru) & lru_mask))
3914 nr += lruvec_page_state(lruvec, NR_LRU_BASE + lru);
3916 nr += lruvec_page_state_local(lruvec, NR_LRU_BASE + lru);
3921 static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup *memcg,
3922 unsigned int lru_mask,
3925 unsigned long nr = 0;
3929 if (!(BIT(lru) & lru_mask))
3932 nr += memcg_page_state(memcg, NR_LRU_BASE + lru);
3934 nr += memcg_page_state_local(memcg, NR_LRU_BASE + lru);
3939 static int memcg_numa_stat_show(struct seq_file *m, void *v)
3943 unsigned int lru_mask;
3946 static const struct numa_stat stats[] = {
3947 { "total", LRU_ALL },
3948 { "file", LRU_ALL_FILE },
3949 { "anon", LRU_ALL_ANON },
3950 { "unevictable", BIT(LRU_UNEVICTABLE) },
3952 const struct numa_stat *stat;
3954 struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
3956 mem_cgroup_flush_stats();
3958 for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) {
3959 seq_printf(m, "%s=%lu", stat->name,
3960 mem_cgroup_nr_lru_pages(memcg, stat->lru_mask,
3962 for_each_node_state(nid, N_MEMORY)
3963 seq_printf(m, " N%d=%lu", nid,
3964 mem_cgroup_node_nr_lru_pages(memcg, nid,
3965 stat->lru_mask, false));
3969 for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) {
3971 seq_printf(m, "hierarchical_%s=%lu", stat->name,
3972 mem_cgroup_nr_lru_pages(memcg, stat->lru_mask,
3974 for_each_node_state(nid, N_MEMORY)
3975 seq_printf(m, " N%d=%lu", nid,
3976 mem_cgroup_node_nr_lru_pages(memcg, nid,
3977 stat->lru_mask, true));
3983 #endif /* CONFIG_NUMA */
3985 static const unsigned int memcg1_stats[] = {
3988 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
3998 static const char *const memcg1_stat_names[] = {
4001 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
4011 /* Universal VM events cgroup1 shows, original sort order */
4012 static const unsigned int memcg1_events[] = {
4019 static int memcg_stat_show(struct seq_file *m, void *v)
4021 struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
4022 unsigned long memory, memsw;
4023 struct mem_cgroup *mi;
4026 BUILD_BUG_ON(ARRAY_SIZE(memcg1_stat_names) != ARRAY_SIZE(memcg1_stats));
4028 mem_cgroup_flush_stats();
4030 for (i = 0; i < ARRAY_SIZE(memcg1_stats); i++) {
4033 if (memcg1_stats[i] == MEMCG_SWAP && !do_memsw_account())
4035 nr = memcg_page_state_local(memcg, memcg1_stats[i]);
4036 seq_printf(m, "%s %lu\n", memcg1_stat_names[i], nr * PAGE_SIZE);
4039 for (i = 0; i < ARRAY_SIZE(memcg1_events); i++)
4040 seq_printf(m, "%s %lu\n", vm_event_name(memcg1_events[i]),
4041 memcg_events_local(memcg, memcg1_events[i]));
4043 for (i = 0; i < NR_LRU_LISTS; i++)
4044 seq_printf(m, "%s %lu\n", lru_list_name(i),
4045 memcg_page_state_local(memcg, NR_LRU_BASE + i) *
4048 /* Hierarchical information */
4049 memory = memsw = PAGE_COUNTER_MAX;
4050 for (mi = memcg; mi; mi = parent_mem_cgroup(mi)) {
4051 memory = min(memory, READ_ONCE(mi->memory.max));
4052 memsw = min(memsw, READ_ONCE(mi->memsw.max));
4054 seq_printf(m, "hierarchical_memory_limit %llu\n",
4055 (u64)memory * PAGE_SIZE);
4056 if (do_memsw_account())
4057 seq_printf(m, "hierarchical_memsw_limit %llu\n",
4058 (u64)memsw * PAGE_SIZE);
4060 for (i = 0; i < ARRAY_SIZE(memcg1_stats); i++) {
4063 if (memcg1_stats[i] == MEMCG_SWAP && !do_memsw_account())
4065 nr = memcg_page_state(memcg, memcg1_stats[i]);
4066 seq_printf(m, "total_%s %llu\n", memcg1_stat_names[i],
4067 (u64)nr * PAGE_SIZE);
4070 for (i = 0; i < ARRAY_SIZE(memcg1_events); i++)
4071 seq_printf(m, "total_%s %llu\n",
4072 vm_event_name(memcg1_events[i]),
4073 (u64)memcg_events(memcg, memcg1_events[i]));
4075 for (i = 0; i < NR_LRU_LISTS; i++)
4076 seq_printf(m, "total_%s %llu\n", lru_list_name(i),
4077 (u64)memcg_page_state(memcg, NR_LRU_BASE + i) *
4080 #ifdef CONFIG_DEBUG_VM
4083 struct mem_cgroup_per_node *mz;
4084 unsigned long anon_cost = 0;
4085 unsigned long file_cost = 0;
4087 for_each_online_pgdat(pgdat) {
4088 mz = memcg->nodeinfo[pgdat->node_id];
4090 anon_cost += mz->lruvec.anon_cost;
4091 file_cost += mz->lruvec.file_cost;
4093 seq_printf(m, "anon_cost %lu\n", anon_cost);
4094 seq_printf(m, "file_cost %lu\n", file_cost);
4101 static u64 mem_cgroup_swappiness_read(struct cgroup_subsys_state *css,
4104 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4106 return mem_cgroup_swappiness(memcg);
4109 static int mem_cgroup_swappiness_write(struct cgroup_subsys_state *css,
4110 struct cftype *cft, u64 val)
4112 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4117 if (!mem_cgroup_is_root(memcg))
4118 memcg->swappiness = val;
4120 vm_swappiness = val;
4125 static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap)
4127 struct mem_cgroup_threshold_ary *t;
4128 unsigned long usage;
4133 t = rcu_dereference(memcg->thresholds.primary);
4135 t = rcu_dereference(memcg->memsw_thresholds.primary);
4140 usage = mem_cgroup_usage(memcg, swap);
4143 * current_threshold points to threshold just below or equal to usage.
4144 * If it's not true, a threshold was crossed after last
4145 * call of __mem_cgroup_threshold().
4147 i = t->current_threshold;
4150 * Iterate backward over array of thresholds starting from
4151 * current_threshold and check if a threshold is crossed.
4152 * If none of thresholds below usage is crossed, we read
4153 * only one element of the array here.
4155 for (; i >= 0 && unlikely(t->entries[i].threshold > usage); i--)
4156 eventfd_signal(t->entries[i].eventfd, 1);
4158 /* i = current_threshold + 1 */
4162 * Iterate forward over array of thresholds starting from
4163 * current_threshold+1 and check if a threshold is crossed.
4164 * If none of thresholds above usage is crossed, we read
4165 * only one element of the array here.
4167 for (; i < t->size && unlikely(t->entries[i].threshold <= usage); i++)
4168 eventfd_signal(t->entries[i].eventfd, 1);
4170 /* Update current_threshold */
4171 t->current_threshold = i - 1;
4176 static void mem_cgroup_threshold(struct mem_cgroup *memcg)
4179 __mem_cgroup_threshold(memcg, false);
4180 if (do_memsw_account())
4181 __mem_cgroup_threshold(memcg, true);
4183 memcg = parent_mem_cgroup(memcg);
4187 static int compare_thresholds(const void *a, const void *b)
4189 const struct mem_cgroup_threshold *_a = a;
4190 const struct mem_cgroup_threshold *_b = b;
4192 if (_a->threshold > _b->threshold)
4195 if (_a->threshold < _b->threshold)
4201 static int mem_cgroup_oom_notify_cb(struct mem_cgroup *memcg)
4203 struct mem_cgroup_eventfd_list *ev;
4205 spin_lock(&memcg_oom_lock);
4207 list_for_each_entry(ev, &memcg->oom_notify, list)
4208 eventfd_signal(ev->eventfd, 1);
4210 spin_unlock(&memcg_oom_lock);
4214 static void mem_cgroup_oom_notify(struct mem_cgroup *memcg)
4216 struct mem_cgroup *iter;
4218 for_each_mem_cgroup_tree(iter, memcg)
4219 mem_cgroup_oom_notify_cb(iter);
4222 static int __mem_cgroup_usage_register_event(struct mem_cgroup *memcg,
4223 struct eventfd_ctx *eventfd, const char *args, enum res_type type)
4225 struct mem_cgroup_thresholds *thresholds;
4226 struct mem_cgroup_threshold_ary *new;
4227 unsigned long threshold;
4228 unsigned long usage;
4231 ret = page_counter_memparse(args, "-1", &threshold);
4235 mutex_lock(&memcg->thresholds_lock);
4238 thresholds = &memcg->thresholds;
4239 usage = mem_cgroup_usage(memcg, false);
4240 } else if (type == _MEMSWAP) {
4241 thresholds = &memcg->memsw_thresholds;
4242 usage = mem_cgroup_usage(memcg, true);
4246 /* Check if a threshold crossed before adding a new one */
4247 if (thresholds->primary)
4248 __mem_cgroup_threshold(memcg, type == _MEMSWAP);
4250 size = thresholds->primary ? thresholds->primary->size + 1 : 1;
4252 /* Allocate memory for new array of thresholds */
4253 new = kmalloc(struct_size(new, entries, size), GFP_KERNEL);
4260 /* Copy thresholds (if any) to new array */
4261 if (thresholds->primary)
4262 memcpy(new->entries, thresholds->primary->entries,
4263 flex_array_size(new, entries, size - 1));
4265 /* Add new threshold */
4266 new->entries[size - 1].eventfd = eventfd;
4267 new->entries[size - 1].threshold = threshold;
4269 /* Sort thresholds. Registering of new threshold isn't time-critical */
4270 sort(new->entries, size, sizeof(*new->entries),
4271 compare_thresholds, NULL);
4273 /* Find current threshold */
4274 new->current_threshold = -1;
4275 for (i = 0; i < size; i++) {
4276 if (new->entries[i].threshold <= usage) {
4278 * new->current_threshold will not be used until
4279 * rcu_assign_pointer(), so it's safe to increment
4282 ++new->current_threshold;
4287 /* Free old spare buffer and save old primary buffer as spare */
4288 kfree(thresholds->spare);
4289 thresholds->spare = thresholds->primary;
4291 rcu_assign_pointer(thresholds->primary, new);
4293 /* To be sure that nobody uses thresholds */
4297 mutex_unlock(&memcg->thresholds_lock);
4302 static int mem_cgroup_usage_register_event(struct mem_cgroup *memcg,
4303 struct eventfd_ctx *eventfd, const char *args)
4305 return __mem_cgroup_usage_register_event(memcg, eventfd, args, _MEM);
4308 static int memsw_cgroup_usage_register_event(struct mem_cgroup *memcg,
4309 struct eventfd_ctx *eventfd, const char *args)
4311 return __mem_cgroup_usage_register_event(memcg, eventfd, args, _MEMSWAP);
4314 static void __mem_cgroup_usage_unregister_event(struct mem_cgroup *memcg,
4315 struct eventfd_ctx *eventfd, enum res_type type)
4317 struct mem_cgroup_thresholds *thresholds;
4318 struct mem_cgroup_threshold_ary *new;
4319 unsigned long usage;
4320 int i, j, size, entries;
4322 mutex_lock(&memcg->thresholds_lock);
4325 thresholds = &memcg->thresholds;
4326 usage = mem_cgroup_usage(memcg, false);
4327 } else if (type == _MEMSWAP) {
4328 thresholds = &memcg->memsw_thresholds;
4329 usage = mem_cgroup_usage(memcg, true);
4333 if (!thresholds->primary)
4336 /* Check if a threshold crossed before removing */
4337 __mem_cgroup_threshold(memcg, type == _MEMSWAP);
4339 /* Calculate new number of threshold */
4341 for (i = 0; i < thresholds->primary->size; i++) {
4342 if (thresholds->primary->entries[i].eventfd != eventfd)
4348 new = thresholds->spare;
4350 /* If no items related to eventfd have been cleared, nothing to do */
4354 /* Set thresholds array to NULL if we don't have thresholds */
4363 /* Copy thresholds and find current threshold */
4364 new->current_threshold = -1;
4365 for (i = 0, j = 0; i < thresholds->primary->size; i++) {
4366 if (thresholds->primary->entries[i].eventfd == eventfd)
4369 new->entries[j] = thresholds->primary->entries[i];
4370 if (new->entries[j].threshold <= usage) {
4372 * new->current_threshold will not be used
4373 * until rcu_assign_pointer(), so it's safe to increment
4376 ++new->current_threshold;
4382 /* Swap primary and spare array */
4383 thresholds->spare = thresholds->primary;
4385 rcu_assign_pointer(thresholds->primary, new);
4387 /* To be sure that nobody uses thresholds */
4390 /* If all events are unregistered, free the spare array */
4392 kfree(thresholds->spare);
4393 thresholds->spare = NULL;
4396 mutex_unlock(&memcg->thresholds_lock);
4399 static void mem_cgroup_usage_unregister_event(struct mem_cgroup *memcg,
4400 struct eventfd_ctx *eventfd)
4402 return __mem_cgroup_usage_unregister_event(memcg, eventfd, _MEM);
4405 static void memsw_cgroup_usage_unregister_event(struct mem_cgroup *memcg,
4406 struct eventfd_ctx *eventfd)
4408 return __mem_cgroup_usage_unregister_event(memcg, eventfd, _MEMSWAP);
4411 static int mem_cgroup_oom_register_event(struct mem_cgroup *memcg,
4412 struct eventfd_ctx *eventfd, const char *args)
4414 struct mem_cgroup_eventfd_list *event;
4416 event = kmalloc(sizeof(*event), GFP_KERNEL);
4420 spin_lock(&memcg_oom_lock);
4422 event->eventfd = eventfd;
4423 list_add(&event->list, &memcg->oom_notify);
4425 /* already in OOM ? */
4426 if (memcg->under_oom)
4427 eventfd_signal(eventfd, 1);
4428 spin_unlock(&memcg_oom_lock);
4433 static void mem_cgroup_oom_unregister_event(struct mem_cgroup *memcg,
4434 struct eventfd_ctx *eventfd)
4436 struct mem_cgroup_eventfd_list *ev, *tmp;
4438 spin_lock(&memcg_oom_lock);
4440 list_for_each_entry_safe(ev, tmp, &memcg->oom_notify, list) {
4441 if (ev->eventfd == eventfd) {
4442 list_del(&ev->list);
4447 spin_unlock(&memcg_oom_lock);
4450 static int mem_cgroup_oom_control_read(struct seq_file *sf, void *v)
4452 struct mem_cgroup *memcg = mem_cgroup_from_seq(sf);
4454 seq_printf(sf, "oom_kill_disable %d\n", memcg->oom_kill_disable);
4455 seq_printf(sf, "under_oom %d\n", (bool)memcg->under_oom);
4456 seq_printf(sf, "oom_kill %lu\n",
4457 atomic_long_read(&memcg->memory_events[MEMCG_OOM_KILL]));
4461 static int mem_cgroup_oom_control_write(struct cgroup_subsys_state *css,
4462 struct cftype *cft, u64 val)
4464 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4466 /* cannot set to root cgroup and only 0 and 1 are allowed */
4467 if (mem_cgroup_is_root(memcg) || !((val == 0) || (val == 1)))
4470 memcg->oom_kill_disable = val;
4472 memcg_oom_recover(memcg);
4477 #ifdef CONFIG_CGROUP_WRITEBACK
4479 #include <trace/events/writeback.h>
4481 static int memcg_wb_domain_init(struct mem_cgroup *memcg, gfp_t gfp)
4483 return wb_domain_init(&memcg->cgwb_domain, gfp);
4486 static void memcg_wb_domain_exit(struct mem_cgroup *memcg)
4488 wb_domain_exit(&memcg->cgwb_domain);
4491 static void memcg_wb_domain_size_changed(struct mem_cgroup *memcg)
4493 wb_domain_size_changed(&memcg->cgwb_domain);
4496 struct wb_domain *mem_cgroup_wb_domain(struct bdi_writeback *wb)
4498 struct mem_cgroup *memcg = mem_cgroup_from_css(wb->memcg_css);
4500 if (!memcg->css.parent)
4503 return &memcg->cgwb_domain;
4507 * mem_cgroup_wb_stats - retrieve writeback related stats from its memcg
4508 * @wb: bdi_writeback in question
4509 * @pfilepages: out parameter for number of file pages
4510 * @pheadroom: out parameter for number of allocatable pages according to memcg
4511 * @pdirty: out parameter for number of dirty pages
4512 * @pwriteback: out parameter for number of pages under writeback
4514 * Determine the numbers of file, headroom, dirty, and writeback pages in
4515 * @wb's memcg. File, dirty and writeback are self-explanatory. Headroom
4516 * is a bit more involved.
4518 * A memcg's headroom is "min(max, high) - used". In the hierarchy, the
4519 * headroom is calculated as the lowest headroom of itself and the
4520 * ancestors. Note that this doesn't consider the actual amount of
4521 * available memory in the system. The caller should further cap
4522 * *@pheadroom accordingly.
4524 void mem_cgroup_wb_stats(struct bdi_writeback *wb, unsigned long *pfilepages,
4525 unsigned long *pheadroom, unsigned long *pdirty,
4526 unsigned long *pwriteback)
4528 struct mem_cgroup *memcg = mem_cgroup_from_css(wb->memcg_css);
4529 struct mem_cgroup *parent;
4531 mem_cgroup_flush_stats();
4533 *pdirty = memcg_page_state(memcg, NR_FILE_DIRTY);
4534 *pwriteback = memcg_page_state(memcg, NR_WRITEBACK);
4535 *pfilepages = memcg_page_state(memcg, NR_INACTIVE_FILE) +
4536 memcg_page_state(memcg, NR_ACTIVE_FILE);
4538 *pheadroom = PAGE_COUNTER_MAX;
4539 while ((parent = parent_mem_cgroup(memcg))) {
4540 unsigned long ceiling = min(READ_ONCE(memcg->memory.max),
4541 READ_ONCE(memcg->memory.high));
4542 unsigned long used = page_counter_read(&memcg->memory);
4544 *pheadroom = min(*pheadroom, ceiling - min(ceiling, used));
4550 * Foreign dirty flushing
4552 * There's an inherent mismatch between memcg and writeback. The former
4553 * tracks ownership per-page while the latter per-inode. This was a
4554 * deliberate design decision because honoring per-page ownership in the
4555 * writeback path is complicated, may lead to higher CPU and IO overheads
4556 * and deemed unnecessary given that write-sharing an inode across
4557 * different cgroups isn't a common use-case.
4559 * Combined with inode majority-writer ownership switching, this works well
4560 * enough in most cases but there are some pathological cases. For
4561 * example, let's say there are two cgroups A and B which keep writing to
4562 * different but confined parts of the same inode. B owns the inode and
4563 * A's memory is limited far below B's. A's dirty ratio can rise enough to
4564 * trigger balance_dirty_pages() sleeps but B's can be low enough to avoid
4565 * triggering background writeback. A will be slowed down without a way to
4566 * make writeback of the dirty pages happen.
4568 * Conditions like the above can lead to a cgroup getting repeatedly and
4569 * severely throttled after making some progress after each
4570 * dirty_expire_interval while the underlying IO device is almost
4573 * Solving this problem completely requires matching the ownership tracking
4574 * granularities between memcg and writeback in either direction. However,
4575 * the more egregious behaviors can be avoided by simply remembering the
4576 * most recent foreign dirtying events and initiating remote flushes on
4577 * them when local writeback isn't enough to keep the memory clean enough.
4579 * The following two functions implement such mechanism. When a foreign
4580 * page - a page whose memcg and writeback ownerships don't match - is
4581 * dirtied, mem_cgroup_track_foreign_dirty() records the inode owning
4582 * bdi_writeback on the page owning memcg. When balance_dirty_pages()
4583 * decides that the memcg needs to sleep due to high dirty ratio, it calls
4584 * mem_cgroup_flush_foreign() which queues writeback on the recorded
4585 * foreign bdi_writebacks which haven't expired. Both the numbers of
4586 * recorded bdi_writebacks and concurrent in-flight foreign writebacks are
4587 * limited to MEMCG_CGWB_FRN_CNT.
4589 * The mechanism only remembers IDs and doesn't hold any object references.
4590 * As being wrong occasionally doesn't matter, updates and accesses to the
4591 * records are lockless and racy.
4593 void mem_cgroup_track_foreign_dirty_slowpath(struct page *page,
4594 struct bdi_writeback *wb)
4596 struct mem_cgroup *memcg = page_memcg(page);
4597 struct memcg_cgwb_frn *frn;
4598 u64 now = get_jiffies_64();
4599 u64 oldest_at = now;
4603 trace_track_foreign_dirty(page, wb);
4606 * Pick the slot to use. If there is already a slot for @wb, keep
4607 * using it. If not replace the oldest one which isn't being
4610 for (i = 0; i < MEMCG_CGWB_FRN_CNT; i++) {
4611 frn = &memcg->cgwb_frn[i];
4612 if (frn->bdi_id == wb->bdi->id &&
4613 frn->memcg_id == wb->memcg_css->id)
4615 if (time_before64(frn->at, oldest_at) &&
4616 atomic_read(&frn->done.cnt) == 1) {
4618 oldest_at = frn->at;
4622 if (i < MEMCG_CGWB_FRN_CNT) {
4624 * Re-using an existing one. Update timestamp lazily to
4625 * avoid making the cacheline hot. We want them to be
4626 * reasonably up-to-date and significantly shorter than
4627 * dirty_expire_interval as that's what expires the record.
4628 * Use the shorter of 1s and dirty_expire_interval / 8.
4630 unsigned long update_intv =
4631 min_t(unsigned long, HZ,
4632 msecs_to_jiffies(dirty_expire_interval * 10) / 8);
4634 if (time_before64(frn->at, now - update_intv))
4636 } else if (oldest >= 0) {
4637 /* replace the oldest free one */
4638 frn = &memcg->cgwb_frn[oldest];
4639 frn->bdi_id = wb->bdi->id;
4640 frn->memcg_id = wb->memcg_css->id;
4645 /* issue foreign writeback flushes for recorded foreign dirtying events */
4646 void mem_cgroup_flush_foreign(struct bdi_writeback *wb)
4648 struct mem_cgroup *memcg = mem_cgroup_from_css(wb->memcg_css);
4649 unsigned long intv = msecs_to_jiffies(dirty_expire_interval * 10);
4650 u64 now = jiffies_64;
4653 for (i = 0; i < MEMCG_CGWB_FRN_CNT; i++) {
4654 struct memcg_cgwb_frn *frn = &memcg->cgwb_frn[i];
4657 * If the record is older than dirty_expire_interval,
4658 * writeback on it has already started. No need to kick it
4659 * off again. Also, don't start a new one if there's
4660 * already one in flight.
4662 if (time_after64(frn->at, now - intv) &&
4663 atomic_read(&frn->done.cnt) == 1) {
4665 trace_flush_foreign(wb, frn->bdi_id, frn->memcg_id);
4666 cgroup_writeback_by_id(frn->bdi_id, frn->memcg_id,
4667 WB_REASON_FOREIGN_FLUSH,
4673 #else /* CONFIG_CGROUP_WRITEBACK */
4675 static int memcg_wb_domain_init(struct mem_cgroup *memcg, gfp_t gfp)
4680 static void memcg_wb_domain_exit(struct mem_cgroup *memcg)
4684 static void memcg_wb_domain_size_changed(struct mem_cgroup *memcg)
4688 #endif /* CONFIG_CGROUP_WRITEBACK */
4691 * DO NOT USE IN NEW FILES.
4693 * "cgroup.event_control" implementation.
4695 * This is way over-engineered. It tries to support fully configurable
4696 * events for each user. Such level of flexibility is completely
4697 * unnecessary especially in the light of the planned unified hierarchy.
4699 * Please deprecate this and replace with something simpler if at all
4704 * Unregister event and free resources.
4706 * Gets called from workqueue.
4708 static void memcg_event_remove(struct work_struct *work)
4710 struct mem_cgroup_event *event =
4711 container_of(work, struct mem_cgroup_event, remove);
4712 struct mem_cgroup *memcg = event->memcg;
4714 remove_wait_queue(event->wqh, &event->wait);
4716 event->unregister_event(memcg, event->eventfd);
4718 /* Notify userspace the event is going away. */
4719 eventfd_signal(event->eventfd, 1);
4721 eventfd_ctx_put(event->eventfd);
4723 css_put(&memcg->css);
4727 * Gets called on EPOLLHUP on eventfd when user closes it.
4729 * Called with wqh->lock held and interrupts disabled.
4731 static int memcg_event_wake(wait_queue_entry_t *wait, unsigned mode,
4732 int sync, void *key)
4734 struct mem_cgroup_event *event =
4735 container_of(wait, struct mem_cgroup_event, wait);
4736 struct mem_cgroup *memcg = event->memcg;
4737 __poll_t flags = key_to_poll(key);
4739 if (flags & EPOLLHUP) {
4741 * If the event has been detached at cgroup removal, we
4742 * can simply return knowing the other side will cleanup
4745 * We can't race against event freeing since the other
4746 * side will require wqh->lock via remove_wait_queue(),
4749 spin_lock(&memcg->event_list_lock);
4750 if (!list_empty(&event->list)) {
4751 list_del_init(&event->list);
4753 * We are in atomic context, but cgroup_event_remove()
4754 * may sleep, so we have to call it in workqueue.
4756 schedule_work(&event->remove);
4758 spin_unlock(&memcg->event_list_lock);
4764 static void memcg_event_ptable_queue_proc(struct file *file,
4765 wait_queue_head_t *wqh, poll_table *pt)
4767 struct mem_cgroup_event *event =
4768 container_of(pt, struct mem_cgroup_event, pt);
4771 add_wait_queue(wqh, &event->wait);
4775 * DO NOT USE IN NEW FILES.
4777 * Parse input and register new cgroup event handler.
4779 * Input must be in format '<event_fd> <control_fd> <args>'.
4780 * Interpretation of args is defined by control file implementation.
4782 static ssize_t memcg_write_event_control(struct kernfs_open_file *of,
4783 char *buf, size_t nbytes, loff_t off)
4785 struct cgroup_subsys_state *css = of_css(of);
4786 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4787 struct mem_cgroup_event *event;
4788 struct cgroup_subsys_state *cfile_css;
4789 unsigned int efd, cfd;
4796 buf = strstrip(buf);
4798 efd = simple_strtoul(buf, &endp, 10);
4803 cfd = simple_strtoul(buf, &endp, 10);
4804 if ((*endp != ' ') && (*endp != '\0'))
4808 event = kzalloc(sizeof(*event), GFP_KERNEL);
4812 event->memcg = memcg;
4813 INIT_LIST_HEAD(&event->list);
4814 init_poll_funcptr(&event->pt, memcg_event_ptable_queue_proc);
4815 init_waitqueue_func_entry(&event->wait, memcg_event_wake);
4816 INIT_WORK(&event->remove, memcg_event_remove);
4824 event->eventfd = eventfd_ctx_fileget(efile.file);
4825 if (IS_ERR(event->eventfd)) {
4826 ret = PTR_ERR(event->eventfd);
4833 goto out_put_eventfd;
4836 /* the process need read permission on control file */
4837 /* AV: shouldn't we check that it's been opened for read instead? */
4838 ret = file_permission(cfile.file, MAY_READ);
4843 * Determine the event callbacks and set them in @event. This used
4844 * to be done via struct cftype but cgroup core no longer knows
4845 * about these events. The following is crude but the whole thing
4846 * is for compatibility anyway.
4848 * DO NOT ADD NEW FILES.
4850 name = cfile.file->f_path.dentry->d_name.name;
4852 if (!strcmp(name, "memory.usage_in_bytes")) {
4853 event->register_event = mem_cgroup_usage_register_event;
4854 event->unregister_event = mem_cgroup_usage_unregister_event;
4855 } else if (!strcmp(name, "memory.oom_control")) {
4856 event->register_event = mem_cgroup_oom_register_event;
4857 event->unregister_event = mem_cgroup_oom_unregister_event;
4858 } else if (!strcmp(name, "memory.pressure_level")) {
4859 event->register_event = vmpressure_register_event;
4860 event->unregister_event = vmpressure_unregister_event;
4861 } else if (!strcmp(name, "memory.memsw.usage_in_bytes")) {
4862 event->register_event = memsw_cgroup_usage_register_event;
4863 event->unregister_event = memsw_cgroup_usage_unregister_event;
4870 * Verify @cfile should belong to @css. Also, remaining events are
4871 * automatically removed on cgroup destruction but the removal is
4872 * asynchronous, so take an extra ref on @css.
4874 cfile_css = css_tryget_online_from_dir(cfile.file->f_path.dentry->d_parent,
4875 &memory_cgrp_subsys);
4877 if (IS_ERR(cfile_css))
4879 if (cfile_css != css) {
4884 ret = event->register_event(memcg, event->eventfd, buf);
4888 vfs_poll(efile.file, &event->pt);
4890 spin_lock_irq(&memcg->event_list_lock);
4891 list_add(&event->list, &memcg->event_list);
4892 spin_unlock_irq(&memcg->event_list_lock);
4904 eventfd_ctx_put(event->eventfd);
4913 static struct cftype mem_cgroup_legacy_files[] = {
4915 .name = "usage_in_bytes",
4916 .private = MEMFILE_PRIVATE(_MEM, RES_USAGE),
4917 .read_u64 = mem_cgroup_read_u64,
4920 .name = "max_usage_in_bytes",
4921 .private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE),
4922 .write = mem_cgroup_reset,
4923 .read_u64 = mem_cgroup_read_u64,
4926 .name = "limit_in_bytes",
4927 .private = MEMFILE_PRIVATE(_MEM, RES_LIMIT),
4928 .write = mem_cgroup_write,
4929 .read_u64 = mem_cgroup_read_u64,
4932 .name = "soft_limit_in_bytes",
4933 .private = MEMFILE_PRIVATE(_MEM, RES_SOFT_LIMIT),
4934 .write = mem_cgroup_write,
4935 .read_u64 = mem_cgroup_read_u64,
4939 .private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT),
4940 .write = mem_cgroup_reset,
4941 .read_u64 = mem_cgroup_read_u64,
4945 .seq_show = memcg_stat_show,
4948 .name = "force_empty",
4949 .write = mem_cgroup_force_empty_write,
4952 .name = "use_hierarchy",
4953 .write_u64 = mem_cgroup_hierarchy_write,
4954 .read_u64 = mem_cgroup_hierarchy_read,
4957 .name = "cgroup.event_control", /* XXX: for compat */
4958 .write = memcg_write_event_control,
4959 .flags = CFTYPE_NO_PREFIX | CFTYPE_WORLD_WRITABLE,
4962 .name = "swappiness",
4963 .read_u64 = mem_cgroup_swappiness_read,
4964 .write_u64 = mem_cgroup_swappiness_write,
4967 .name = "move_charge_at_immigrate",
4968 .read_u64 = mem_cgroup_move_charge_read,
4969 .write_u64 = mem_cgroup_move_charge_write,
4972 .name = "oom_control",
4973 .seq_show = mem_cgroup_oom_control_read,
4974 .write_u64 = mem_cgroup_oom_control_write,
4975 .private = MEMFILE_PRIVATE(_OOM_TYPE, OOM_CONTROL),
4978 .name = "pressure_level",
4982 .name = "numa_stat",
4983 .seq_show = memcg_numa_stat_show,
4987 .name = "kmem.limit_in_bytes",
4988 .private = MEMFILE_PRIVATE(_KMEM, RES_LIMIT),
4989 .write = mem_cgroup_write,
4990 .read_u64 = mem_cgroup_read_u64,
4993 .name = "kmem.usage_in_bytes",
4994 .private = MEMFILE_PRIVATE(_KMEM, RES_USAGE),
4995 .read_u64 = mem_cgroup_read_u64,
4998 .name = "kmem.failcnt",
4999 .private = MEMFILE_PRIVATE(_KMEM, RES_FAILCNT),
5000 .write = mem_cgroup_reset,
5001 .read_u64 = mem_cgroup_read_u64,
5004 .name = "kmem.max_usage_in_bytes",
5005 .private = MEMFILE_PRIVATE(_KMEM, RES_MAX_USAGE),
5006 .write = mem_cgroup_reset,
5007 .read_u64 = mem_cgroup_read_u64,
5009 #if defined(CONFIG_MEMCG_KMEM) && \
5010 (defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG))
5012 .name = "kmem.slabinfo",
5013 .seq_show = memcg_slab_show,
5017 .name = "kmem.tcp.limit_in_bytes",
5018 .private = MEMFILE_PRIVATE(_TCP, RES_LIMIT),
5019 .write = mem_cgroup_write,
5020 .read_u64 = mem_cgroup_read_u64,
5023 .name = "kmem.tcp.usage_in_bytes",
5024 .private = MEMFILE_PRIVATE(_TCP, RES_USAGE),
5025 .read_u64 = mem_cgroup_read_u64,
5028 .name = "kmem.tcp.failcnt",
5029 .private = MEMFILE_PRIVATE(_TCP, RES_FAILCNT),
5030 .write = mem_cgroup_reset,
5031 .read_u64 = mem_cgroup_read_u64,
5034 .name = "kmem.tcp.max_usage_in_bytes",
5035 .private = MEMFILE_PRIVATE(_TCP, RES_MAX_USAGE),
5036 .write = mem_cgroup_reset,
5037 .read_u64 = mem_cgroup_read_u64,
5039 { }, /* terminate */
5043 * Private memory cgroup IDR
5045 * Swap-out records and page cache shadow entries need to store memcg
5046 * references in constrained space, so we maintain an ID space that is
5047 * limited to 16 bit (MEM_CGROUP_ID_MAX), limiting the total number of
5048 * memory-controlled cgroups to 64k.
5050 * However, there usually are many references to the offline CSS after
5051 * the cgroup has been destroyed, such as page cache or reclaimable
5052 * slab objects, that don't need to hang on to the ID. We want to keep
5053 * those dead CSS from occupying IDs, or we might quickly exhaust the
5054 * relatively small ID space and prevent the creation of new cgroups
5055 * even when there are much fewer than 64k cgroups - possibly none.
5057 * Maintain a private 16-bit ID space for memcg, and allow the ID to
5058 * be freed and recycled when it's no longer needed, which is usually
5059 * when the CSS is offlined.
5061 * The only exception to that are records of swapped out tmpfs/shmem
5062 * pages that need to be attributed to live ancestors on swapin. But
5063 * those references are manageable from userspace.
5066 static DEFINE_IDR(mem_cgroup_idr);
5068 static void mem_cgroup_id_remove(struct mem_cgroup *memcg)
5070 if (memcg->id.id > 0) {
5071 idr_remove(&mem_cgroup_idr, memcg->id.id);
5076 static void __maybe_unused mem_cgroup_id_get_many(struct mem_cgroup *memcg,
5079 refcount_add(n, &memcg->id.ref);
5082 static void mem_cgroup_id_put_many(struct mem_cgroup *memcg, unsigned int n)
5084 if (refcount_sub_and_test(n, &memcg->id.ref)) {
5085 mem_cgroup_id_remove(memcg);
5087 /* Memcg ID pins CSS */
5088 css_put(&memcg->css);
5092 static inline void mem_cgroup_id_put(struct mem_cgroup *memcg)
5094 mem_cgroup_id_put_many(memcg, 1);
5098 * mem_cgroup_from_id - look up a memcg from a memcg id
5099 * @id: the memcg id to look up
5101 * Caller must hold rcu_read_lock().
5103 struct mem_cgroup *mem_cgroup_from_id(unsigned short id)
5105 WARN_ON_ONCE(!rcu_read_lock_held());
5106 return idr_find(&mem_cgroup_idr, id);
5109 static int alloc_mem_cgroup_per_node_info(struct mem_cgroup *memcg, int node)
5111 struct mem_cgroup_per_node *pn;
5114 * This routine is called against possible nodes.
5115 * But it's BUG to call kmalloc() against offline node.
5117 * TODO: this routine can waste much memory for nodes which will
5118 * never be onlined. It's better to use memory hotplug callback
5121 if (!node_state(node, N_NORMAL_MEMORY))
5123 pn = kzalloc_node(sizeof(*pn), GFP_KERNEL, tmp);
5127 pn->lruvec_stats_percpu = alloc_percpu_gfp(struct lruvec_stats_percpu,
5128 GFP_KERNEL_ACCOUNT);
5129 if (!pn->lruvec_stats_percpu) {
5134 lruvec_init(&pn->lruvec);
5135 pn->usage_in_excess = 0;
5136 pn->on_tree = false;
5139 memcg->nodeinfo[node] = pn;
5143 static void free_mem_cgroup_per_node_info(struct mem_cgroup *memcg, int node)
5145 struct mem_cgroup_per_node *pn = memcg->nodeinfo[node];
5150 free_percpu(pn->lruvec_stats_percpu);
5154 static void __mem_cgroup_free(struct mem_cgroup *memcg)
5159 free_mem_cgroup_per_node_info(memcg, node);
5160 free_percpu(memcg->vmstats_percpu);
5164 static void mem_cgroup_free(struct mem_cgroup *memcg)
5166 memcg_wb_domain_exit(memcg);
5167 __mem_cgroup_free(memcg);
5170 static struct mem_cgroup *mem_cgroup_alloc(void)
5172 struct mem_cgroup *memcg;
5175 int __maybe_unused i;
5176 long error = -ENOMEM;
5178 size = sizeof(struct mem_cgroup);
5179 size += nr_node_ids * sizeof(struct mem_cgroup_per_node *);
5181 memcg = kzalloc(size, GFP_KERNEL);
5183 return ERR_PTR(error);
5185 memcg->id.id = idr_alloc(&mem_cgroup_idr, NULL,
5186 1, MEM_CGROUP_ID_MAX,
5188 if (memcg->id.id < 0) {
5189 error = memcg->id.id;
5193 memcg->vmstats_percpu = alloc_percpu_gfp(struct memcg_vmstats_percpu,
5194 GFP_KERNEL_ACCOUNT);
5195 if (!memcg->vmstats_percpu)
5199 if (alloc_mem_cgroup_per_node_info(memcg, node))
5202 if (memcg_wb_domain_init(memcg, GFP_KERNEL))
5205 INIT_WORK(&memcg->high_work, high_work_func);
5206 INIT_LIST_HEAD(&memcg->oom_notify);
5207 mutex_init(&memcg->thresholds_lock);
5208 spin_lock_init(&memcg->move_lock);
5209 vmpressure_init(&memcg->vmpressure);
5210 INIT_LIST_HEAD(&memcg->event_list);
5211 spin_lock_init(&memcg->event_list_lock);
5212 memcg->socket_pressure = jiffies;
5213 #ifdef CONFIG_MEMCG_KMEM
5214 memcg->kmemcg_id = -1;
5215 INIT_LIST_HEAD(&memcg->objcg_list);
5217 #ifdef CONFIG_CGROUP_WRITEBACK
5218 INIT_LIST_HEAD(&memcg->cgwb_list);
5219 for (i = 0; i < MEMCG_CGWB_FRN_CNT; i++)
5220 memcg->cgwb_frn[i].done =
5221 __WB_COMPLETION_INIT(&memcg_cgwb_frn_waitq);
5223 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
5224 spin_lock_init(&memcg->deferred_split_queue.split_queue_lock);
5225 INIT_LIST_HEAD(&memcg->deferred_split_queue.split_queue);
5226 memcg->deferred_split_queue.split_queue_len = 0;
5228 idr_replace(&mem_cgroup_idr, memcg, memcg->id.id);
5231 mem_cgroup_id_remove(memcg);
5232 __mem_cgroup_free(memcg);
5233 return ERR_PTR(error);
5236 static struct cgroup_subsys_state * __ref
5237 mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
5239 struct mem_cgroup *parent = mem_cgroup_from_css(parent_css);
5240 struct mem_cgroup *memcg, *old_memcg;
5241 long error = -ENOMEM;
5243 old_memcg = set_active_memcg(parent);
5244 memcg = mem_cgroup_alloc();
5245 set_active_memcg(old_memcg);
5247 return ERR_CAST(memcg);
5249 page_counter_set_high(&memcg->memory, PAGE_COUNTER_MAX);
5250 memcg->soft_limit = PAGE_COUNTER_MAX;
5251 page_counter_set_high(&memcg->swap, PAGE_COUNTER_MAX);
5253 memcg->swappiness = mem_cgroup_swappiness(parent);
5254 memcg->oom_kill_disable = parent->oom_kill_disable;
5256 page_counter_init(&memcg->memory, &parent->memory);
5257 page_counter_init(&memcg->swap, &parent->swap);
5258 page_counter_init(&memcg->kmem, &parent->kmem);
5259 page_counter_init(&memcg->tcpmem, &parent->tcpmem);
5261 page_counter_init(&memcg->memory, NULL);
5262 page_counter_init(&memcg->swap, NULL);
5263 page_counter_init(&memcg->kmem, NULL);
5264 page_counter_init(&memcg->tcpmem, NULL);
5266 root_mem_cgroup = memcg;
5270 /* The following stuff does not apply to the root */
5271 error = memcg_online_kmem(memcg);
5275 if (cgroup_subsys_on_dfl(memory_cgrp_subsys) && !cgroup_memory_nosocket)
5276 static_branch_inc(&memcg_sockets_enabled_key);
5280 mem_cgroup_id_remove(memcg);
5281 mem_cgroup_free(memcg);
5282 return ERR_PTR(error);
5285 static int mem_cgroup_css_online(struct cgroup_subsys_state *css)
5287 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5290 * A memcg must be visible for expand_shrinker_info()
5291 * by the time the maps are allocated. So, we allocate maps
5292 * here, when for_each_mem_cgroup() can't skip it.
5294 if (alloc_shrinker_info(memcg)) {
5295 mem_cgroup_id_remove(memcg);
5299 /* Online state pins memcg ID, memcg ID pins CSS */
5300 refcount_set(&memcg->id.ref, 1);
5303 if (unlikely(mem_cgroup_is_root(memcg)))
5304 queue_delayed_work(system_unbound_wq, &stats_flush_dwork,
5309 static void mem_cgroup_css_offline(struct cgroup_subsys_state *css)
5311 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5312 struct mem_cgroup_event *event, *tmp;
5315 * Unregister events and notify userspace.
5316 * Notify userspace about cgroup removing only after rmdir of cgroup
5317 * directory to avoid race between userspace and kernelspace.
5319 spin_lock_irq(&memcg->event_list_lock);
5320 list_for_each_entry_safe(event, tmp, &memcg->event_list, list) {
5321 list_del_init(&event->list);
5322 schedule_work(&event->remove);
5324 spin_unlock_irq(&memcg->event_list_lock);
5326 page_counter_set_min(&memcg->memory, 0);
5327 page_counter_set_low(&memcg->memory, 0);
5329 memcg_offline_kmem(memcg);
5330 reparent_shrinker_deferred(memcg);
5331 wb_memcg_offline(memcg);
5333 drain_all_stock(memcg);
5335 mem_cgroup_id_put(memcg);
5338 static void mem_cgroup_css_released(struct cgroup_subsys_state *css)
5340 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5342 invalidate_reclaim_iterators(memcg);
5345 static void mem_cgroup_css_free(struct cgroup_subsys_state *css)
5347 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5348 int __maybe_unused i;
5350 #ifdef CONFIG_CGROUP_WRITEBACK
5351 for (i = 0; i < MEMCG_CGWB_FRN_CNT; i++)
5352 wb_wait_for_completion(&memcg->cgwb_frn[i].done);
5354 if (cgroup_subsys_on_dfl(memory_cgrp_subsys) && !cgroup_memory_nosocket)
5355 static_branch_dec(&memcg_sockets_enabled_key);
5357 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && memcg->tcpmem_active)
5358 static_branch_dec(&memcg_sockets_enabled_key);
5360 vmpressure_cleanup(&memcg->vmpressure);
5361 cancel_work_sync(&memcg->high_work);
5362 mem_cgroup_remove_from_trees(memcg);
5363 free_shrinker_info(memcg);
5364 memcg_free_kmem(memcg);
5365 mem_cgroup_free(memcg);
5369 * mem_cgroup_css_reset - reset the states of a mem_cgroup
5370 * @css: the target css
5372 * Reset the states of the mem_cgroup associated with @css. This is
5373 * invoked when the userland requests disabling on the default hierarchy
5374 * but the memcg is pinned through dependency. The memcg should stop
5375 * applying policies and should revert to the vanilla state as it may be
5376 * made visible again.
5378 * The current implementation only resets the essential configurations.
5379 * This needs to be expanded to cover all the visible parts.
5381 static void mem_cgroup_css_reset(struct cgroup_subsys_state *css)
5383 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5385 page_counter_set_max(&memcg->memory, PAGE_COUNTER_MAX);
5386 page_counter_set_max(&memcg->swap, PAGE_COUNTER_MAX);
5387 page_counter_set_max(&memcg->kmem, PAGE_COUNTER_MAX);
5388 page_counter_set_max(&memcg->tcpmem, PAGE_COUNTER_MAX);
5389 page_counter_set_min(&memcg->memory, 0);
5390 page_counter_set_low(&memcg->memory, 0);
5391 page_counter_set_high(&memcg->memory, PAGE_COUNTER_MAX);
5392 memcg->soft_limit = PAGE_COUNTER_MAX;
5393 page_counter_set_high(&memcg->swap, PAGE_COUNTER_MAX);
5394 memcg_wb_domain_size_changed(memcg);
5397 static void mem_cgroup_css_rstat_flush(struct cgroup_subsys_state *css, int cpu)
5399 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5400 struct mem_cgroup *parent = parent_mem_cgroup(memcg);
5401 struct memcg_vmstats_percpu *statc;
5405 statc = per_cpu_ptr(memcg->vmstats_percpu, cpu);
5407 for (i = 0; i < MEMCG_NR_STAT; i++) {
5409 * Collect the aggregated propagation counts of groups
5410 * below us. We're in a per-cpu loop here and this is
5411 * a global counter, so the first cycle will get them.
5413 delta = memcg->vmstats.state_pending[i];
5415 memcg->vmstats.state_pending[i] = 0;
5417 /* Add CPU changes on this level since the last flush */
5418 v = READ_ONCE(statc->state[i]);
5419 if (v != statc->state_prev[i]) {
5420 delta += v - statc->state_prev[i];
5421 statc->state_prev[i] = v;
5427 /* Aggregate counts on this level and propagate upwards */
5428 memcg->vmstats.state[i] += delta;
5430 parent->vmstats.state_pending[i] += delta;
5433 for (i = 0; i < NR_VM_EVENT_ITEMS; i++) {
5434 delta = memcg->vmstats.events_pending[i];
5436 memcg->vmstats.events_pending[i] = 0;
5438 v = READ_ONCE(statc->events[i]);
5439 if (v != statc->events_prev[i]) {
5440 delta += v - statc->events_prev[i];
5441 statc->events_prev[i] = v;
5447 memcg->vmstats.events[i] += delta;
5449 parent->vmstats.events_pending[i] += delta;
5452 for_each_node_state(nid, N_MEMORY) {
5453 struct mem_cgroup_per_node *pn = memcg->nodeinfo[nid];
5454 struct mem_cgroup_per_node *ppn = NULL;
5455 struct lruvec_stats_percpu *lstatc;
5458 ppn = parent->nodeinfo[nid];
5460 lstatc = per_cpu_ptr(pn->lruvec_stats_percpu, cpu);
5462 for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) {
5463 delta = pn->lruvec_stats.state_pending[i];
5465 pn->lruvec_stats.state_pending[i] = 0;
5467 v = READ_ONCE(lstatc->state[i]);
5468 if (v != lstatc->state_prev[i]) {
5469 delta += v - lstatc->state_prev[i];
5470 lstatc->state_prev[i] = v;
5476 pn->lruvec_stats.state[i] += delta;
5478 ppn->lruvec_stats.state_pending[i] += delta;
5484 /* Handlers for move charge at task migration. */
5485 static int mem_cgroup_do_precharge(unsigned long count)
5489 /* Try a single bulk charge without reclaim first, kswapd may wake */
5490 ret = try_charge(mc.to, GFP_KERNEL & ~__GFP_DIRECT_RECLAIM, count);
5492 mc.precharge += count;
5496 /* Try charges one by one with reclaim, but do not retry */
5498 ret = try_charge(mc.to, GFP_KERNEL | __GFP_NORETRY, 1);
5512 enum mc_target_type {
5519 static struct page *mc_handle_present_pte(struct vm_area_struct *vma,
5520 unsigned long addr, pte_t ptent)
5522 struct page *page = vm_normal_page(vma, addr, ptent);
5524 if (!page || !page_mapped(page))
5526 if (PageAnon(page)) {
5527 if (!(mc.flags & MOVE_ANON))
5530 if (!(mc.flags & MOVE_FILE))
5533 if (!get_page_unless_zero(page))
5539 #if defined(CONFIG_SWAP) || defined(CONFIG_DEVICE_PRIVATE)
5540 static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
5541 pte_t ptent, swp_entry_t *entry)
5543 struct page *page = NULL;
5544 swp_entry_t ent = pte_to_swp_entry(ptent);
5546 if (!(mc.flags & MOVE_ANON))
5550 * Handle MEMORY_DEVICE_PRIVATE which are ZONE_DEVICE page belonging to
5551 * a device and because they are not accessible by CPU they are store
5552 * as special swap entry in the CPU page table.
5554 if (is_device_private_entry(ent)) {
5555 page = pfn_swap_entry_to_page(ent);
5557 * MEMORY_DEVICE_PRIVATE means ZONE_DEVICE page and which have
5558 * a refcount of 1 when free (unlike normal page)
5560 if (!page_ref_add_unless(page, 1, 1))
5565 if (non_swap_entry(ent))
5569 * Because lookup_swap_cache() updates some statistics counter,
5570 * we call find_get_page() with swapper_space directly.
5572 page = find_get_page(swap_address_space(ent), swp_offset(ent));
5573 entry->val = ent.val;
5578 static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
5579 pte_t ptent, swp_entry_t *entry)
5585 static struct page *mc_handle_file_pte(struct vm_area_struct *vma,
5586 unsigned long addr, pte_t ptent, swp_entry_t *entry)
5588 if (!vma->vm_file) /* anonymous vma */
5590 if (!(mc.flags & MOVE_FILE))
5593 /* page is moved even if it's not RSS of this task(page-faulted). */
5594 /* shmem/tmpfs may report page out on swap: account for that too. */
5595 return find_get_incore_page(vma->vm_file->f_mapping,
5596 linear_page_index(vma, addr));
5600 * mem_cgroup_move_account - move account of the page
5602 * @compound: charge the page as compound or small page
5603 * @from: mem_cgroup which the page is moved from.
5604 * @to: mem_cgroup which the page is moved to. @from != @to.
5606 * The caller must make sure the page is not on LRU (isolate_page() is useful.)
5608 * This function doesn't do "charge" to new cgroup and doesn't do "uncharge"
5611 static int mem_cgroup_move_account(struct page *page,
5613 struct mem_cgroup *from,
5614 struct mem_cgroup *to)
5616 struct lruvec *from_vec, *to_vec;
5617 struct pglist_data *pgdat;
5618 unsigned int nr_pages = compound ? thp_nr_pages(page) : 1;
5621 VM_BUG_ON(from == to);
5622 VM_BUG_ON_PAGE(PageLRU(page), page);
5623 VM_BUG_ON(compound && !PageTransHuge(page));
5626 * Prevent mem_cgroup_migrate() from looking at
5627 * page's memory cgroup of its source page while we change it.
5630 if (!trylock_page(page))
5634 if (page_memcg(page) != from)
5637 pgdat = page_pgdat(page);
5638 from_vec = mem_cgroup_lruvec(from, pgdat);
5639 to_vec = mem_cgroup_lruvec(to, pgdat);
5641 lock_page_memcg(page);
5643 if (PageAnon(page)) {
5644 if (page_mapped(page)) {
5645 __mod_lruvec_state(from_vec, NR_ANON_MAPPED, -nr_pages);
5646 __mod_lruvec_state(to_vec, NR_ANON_MAPPED, nr_pages);
5647 if (PageTransHuge(page)) {
5648 __mod_lruvec_state(from_vec, NR_ANON_THPS,
5650 __mod_lruvec_state(to_vec, NR_ANON_THPS,
5655 __mod_lruvec_state(from_vec, NR_FILE_PAGES, -nr_pages);
5656 __mod_lruvec_state(to_vec, NR_FILE_PAGES, nr_pages);
5658 if (PageSwapBacked(page)) {
5659 __mod_lruvec_state(from_vec, NR_SHMEM, -nr_pages);
5660 __mod_lruvec_state(to_vec, NR_SHMEM, nr_pages);
5663 if (page_mapped(page)) {
5664 __mod_lruvec_state(from_vec, NR_FILE_MAPPED, -nr_pages);
5665 __mod_lruvec_state(to_vec, NR_FILE_MAPPED, nr_pages);
5668 if (PageDirty(page)) {
5669 struct address_space *mapping = page_mapping(page);
5671 if (mapping_can_writeback(mapping)) {
5672 __mod_lruvec_state(from_vec, NR_FILE_DIRTY,
5674 __mod_lruvec_state(to_vec, NR_FILE_DIRTY,
5680 if (PageWriteback(page)) {
5681 __mod_lruvec_state(from_vec, NR_WRITEBACK, -nr_pages);
5682 __mod_lruvec_state(to_vec, NR_WRITEBACK, nr_pages);
5686 * All state has been migrated, let's switch to the new memcg.
5688 * It is safe to change page's memcg here because the page
5689 * is referenced, charged, isolated, and locked: we can't race
5690 * with (un)charging, migration, LRU putback, or anything else
5691 * that would rely on a stable page's memory cgroup.
5693 * Note that lock_page_memcg is a memcg lock, not a page lock,
5694 * to save space. As soon as we switch page's memory cgroup to a
5695 * new memcg that isn't locked, the above state can change
5696 * concurrently again. Make sure we're truly done with it.
5701 css_put(&from->css);
5703 page->memcg_data = (unsigned long)to;
5705 __unlock_page_memcg(from);
5709 local_irq_disable();
5710 mem_cgroup_charge_statistics(to, page, nr_pages);
5711 memcg_check_events(to, page);
5712 mem_cgroup_charge_statistics(from, page, -nr_pages);
5713 memcg_check_events(from, page);
5722 * get_mctgt_type - get target type of moving charge
5723 * @vma: the vma the pte to be checked belongs
5724 * @addr: the address corresponding to the pte to be checked
5725 * @ptent: the pte to be checked
5726 * @target: the pointer the target page or swap ent will be stored(can be NULL)
5729 * 0(MC_TARGET_NONE): if the pte is not a target for move charge.
5730 * 1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for
5731 * move charge. if @target is not NULL, the page is stored in target->page
5732 * with extra refcnt got(Callers should handle it).
5733 * 2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a
5734 * target for charge migration. if @target is not NULL, the entry is stored
5736 * 3(MC_TARGET_DEVICE): like MC_TARGET_PAGE but page is MEMORY_DEVICE_PRIVATE
5737 * (so ZONE_DEVICE page and thus not on the lru).
5738 * For now we such page is charge like a regular page would be as for all
5739 * intent and purposes it is just special memory taking the place of a
5742 * See Documentations/vm/hmm.txt and include/linux/hmm.h
5744 * Called with pte lock held.
5747 static enum mc_target_type get_mctgt_type(struct vm_area_struct *vma,
5748 unsigned long addr, pte_t ptent, union mc_target *target)
5750 struct page *page = NULL;
5751 enum mc_target_type ret = MC_TARGET_NONE;
5752 swp_entry_t ent = { .val = 0 };
5754 if (pte_present(ptent))
5755 page = mc_handle_present_pte(vma, addr, ptent);
5756 else if (is_swap_pte(ptent))
5757 page = mc_handle_swap_pte(vma, ptent, &ent);
5758 else if (pte_none(ptent))
5759 page = mc_handle_file_pte(vma, addr, ptent, &ent);
5761 if (!page && !ent.val)
5765 * Do only loose check w/o serialization.
5766 * mem_cgroup_move_account() checks the page is valid or
5767 * not under LRU exclusion.
5769 if (page_memcg(page) == mc.from) {
5770 ret = MC_TARGET_PAGE;
5771 if (is_device_private_page(page))
5772 ret = MC_TARGET_DEVICE;
5774 target->page = page;
5776 if (!ret || !target)
5780 * There is a swap entry and a page doesn't exist or isn't charged.
5781 * But we cannot move a tail-page in a THP.
5783 if (ent.val && !ret && (!page || !PageTransCompound(page)) &&
5784 mem_cgroup_id(mc.from) == lookup_swap_cgroup_id(ent)) {
5785 ret = MC_TARGET_SWAP;
5792 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
5794 * We don't consider PMD mapped swapping or file mapped pages because THP does
5795 * not support them for now.
5796 * Caller should make sure that pmd_trans_huge(pmd) is true.
5798 static enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma,
5799 unsigned long addr, pmd_t pmd, union mc_target *target)
5801 struct page *page = NULL;
5802 enum mc_target_type ret = MC_TARGET_NONE;
5804 if (unlikely(is_swap_pmd(pmd))) {
5805 VM_BUG_ON(thp_migration_supported() &&
5806 !is_pmd_migration_entry(pmd));
5809 page = pmd_page(pmd);
5810 VM_BUG_ON_PAGE(!page || !PageHead(page), page);
5811 if (!(mc.flags & MOVE_ANON))
5813 if (page_memcg(page) == mc.from) {
5814 ret = MC_TARGET_PAGE;
5817 target->page = page;
5823 static inline enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma,
5824 unsigned long addr, pmd_t pmd, union mc_target *target)
5826 return MC_TARGET_NONE;
5830 static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd,
5831 unsigned long addr, unsigned long end,
5832 struct mm_walk *walk)
5834 struct vm_area_struct *vma = walk->vma;
5838 ptl = pmd_trans_huge_lock(pmd, vma);
5841 * Note their can not be MC_TARGET_DEVICE for now as we do not
5842 * support transparent huge page with MEMORY_DEVICE_PRIVATE but
5843 * this might change.
5845 if (get_mctgt_type_thp(vma, addr, *pmd, NULL) == MC_TARGET_PAGE)
5846 mc.precharge += HPAGE_PMD_NR;
5851 if (pmd_trans_unstable(pmd))
5853 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
5854 for (; addr != end; pte++, addr += PAGE_SIZE)
5855 if (get_mctgt_type(vma, addr, *pte, NULL))
5856 mc.precharge++; /* increment precharge temporarily */
5857 pte_unmap_unlock(pte - 1, ptl);
5863 static const struct mm_walk_ops precharge_walk_ops = {
5864 .pmd_entry = mem_cgroup_count_precharge_pte_range,
5867 static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm)
5869 unsigned long precharge;
5872 walk_page_range(mm, 0, mm->highest_vm_end, &precharge_walk_ops, NULL);
5873 mmap_read_unlock(mm);
5875 precharge = mc.precharge;
5881 static int mem_cgroup_precharge_mc(struct mm_struct *mm)
5883 unsigned long precharge = mem_cgroup_count_precharge(mm);
5885 VM_BUG_ON(mc.moving_task);
5886 mc.moving_task = current;
5887 return mem_cgroup_do_precharge(precharge);
5890 /* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */
5891 static void __mem_cgroup_clear_mc(void)
5893 struct mem_cgroup *from = mc.from;
5894 struct mem_cgroup *to = mc.to;
5896 /* we must uncharge all the leftover precharges from mc.to */
5898 cancel_charge(mc.to, mc.precharge);
5902 * we didn't uncharge from mc.from at mem_cgroup_move_account(), so
5903 * we must uncharge here.
5905 if (mc.moved_charge) {
5906 cancel_charge(mc.from, mc.moved_charge);
5907 mc.moved_charge = 0;
5909 /* we must fixup refcnts and charges */
5910 if (mc.moved_swap) {
5911 /* uncharge swap account from the old cgroup */
5912 if (!mem_cgroup_is_root(mc.from))
5913 page_counter_uncharge(&mc.from->memsw, mc.moved_swap);
5915 mem_cgroup_id_put_many(mc.from, mc.moved_swap);
5918 * we charged both to->memory and to->memsw, so we
5919 * should uncharge to->memory.
5921 if (!mem_cgroup_is_root(mc.to))
5922 page_counter_uncharge(&mc.to->memory, mc.moved_swap);
5926 memcg_oom_recover(from);
5927 memcg_oom_recover(to);
5928 wake_up_all(&mc.waitq);
5931 static void mem_cgroup_clear_mc(void)
5933 struct mm_struct *mm = mc.mm;
5936 * we must clear moving_task before waking up waiters at the end of
5939 mc.moving_task = NULL;
5940 __mem_cgroup_clear_mc();
5941 spin_lock(&mc.lock);
5945 spin_unlock(&mc.lock);
5950 static int mem_cgroup_can_attach(struct cgroup_taskset *tset)
5952 struct cgroup_subsys_state *css;
5953 struct mem_cgroup *memcg = NULL; /* unneeded init to make gcc happy */
5954 struct mem_cgroup *from;
5955 struct task_struct *leader, *p;
5956 struct mm_struct *mm;
5957 unsigned long move_flags;
5960 /* charge immigration isn't supported on the default hierarchy */
5961 if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
5965 * Multi-process migrations only happen on the default hierarchy
5966 * where charge immigration is not used. Perform charge
5967 * immigration if @tset contains a leader and whine if there are
5971 cgroup_taskset_for_each_leader(leader, css, tset) {
5974 memcg = mem_cgroup_from_css(css);
5980 * We are now committed to this value whatever it is. Changes in this
5981 * tunable will only affect upcoming migrations, not the current one.
5982 * So we need to save it, and keep it going.
5984 move_flags = READ_ONCE(memcg->move_charge_at_immigrate);
5988 from = mem_cgroup_from_task(p);
5990 VM_BUG_ON(from == memcg);
5992 mm = get_task_mm(p);
5995 /* We move charges only when we move a owner of the mm */
5996 if (mm->owner == p) {
5999 VM_BUG_ON(mc.precharge);
6000 VM_BUG_ON(mc.moved_charge);
6001 VM_BUG_ON(mc.moved_swap);
6003 spin_lock(&mc.lock);
6007 mc.flags = move_flags;
6008 spin_unlock(&mc.lock);
6009 /* We set mc.moving_task later */
6011 ret = mem_cgroup_precharge_mc(mm);
6013 mem_cgroup_clear_mc();
6020 static void mem_cgroup_cancel_attach(struct cgroup_taskset *tset)
6023 mem_cgroup_clear_mc();
6026 static int mem_cgroup_move_charge_pte_range(pmd_t *pmd,
6027 unsigned long addr, unsigned long end,
6028 struct mm_walk *walk)
6031 struct vm_area_struct *vma = walk->vma;
6034 enum mc_target_type target_type;
6035 union mc_target target;
6038 ptl = pmd_trans_huge_lock(pmd, vma);
6040 if (mc.precharge < HPAGE_PMD_NR) {
6044 target_type = get_mctgt_type_thp(vma, addr, *pmd, &target);
6045 if (target_type == MC_TARGET_PAGE) {
6047 if (!isolate_lru_page(page)) {
6048 if (!mem_cgroup_move_account(page, true,
6050 mc.precharge -= HPAGE_PMD_NR;
6051 mc.moved_charge += HPAGE_PMD_NR;
6053 putback_lru_page(page);
6056 } else if (target_type == MC_TARGET_DEVICE) {
6058 if (!mem_cgroup_move_account(page, true,
6060 mc.precharge -= HPAGE_PMD_NR;
6061 mc.moved_charge += HPAGE_PMD_NR;
6069 if (pmd_trans_unstable(pmd))
6072 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
6073 for (; addr != end; addr += PAGE_SIZE) {
6074 pte_t ptent = *(pte++);
6075 bool device = false;
6081 switch (get_mctgt_type(vma, addr, ptent, &target)) {
6082 case MC_TARGET_DEVICE:
6085 case MC_TARGET_PAGE:
6088 * We can have a part of the split pmd here. Moving it
6089 * can be done but it would be too convoluted so simply
6090 * ignore such a partial THP and keep it in original
6091 * memcg. There should be somebody mapping the head.
6093 if (PageTransCompound(page))
6095 if (!device && isolate_lru_page(page))
6097 if (!mem_cgroup_move_account(page, false,
6100 /* we uncharge from mc.from later. */
6104 putback_lru_page(page);
6105 put: /* get_mctgt_type() gets the page */
6108 case MC_TARGET_SWAP:
6110 if (!mem_cgroup_move_swap_account(ent, mc.from, mc.to)) {
6112 mem_cgroup_id_get_many(mc.to, 1);
6113 /* we fixup other refcnts and charges later. */
6121 pte_unmap_unlock(pte - 1, ptl);
6126 * We have consumed all precharges we got in can_attach().
6127 * We try charge one by one, but don't do any additional
6128 * charges to mc.to if we have failed in charge once in attach()
6131 ret = mem_cgroup_do_precharge(1);
6139 static const struct mm_walk_ops charge_walk_ops = {
6140 .pmd_entry = mem_cgroup_move_charge_pte_range,
6143 static void mem_cgroup_move_charge(void)
6145 lru_add_drain_all();
6147 * Signal lock_page_memcg() to take the memcg's move_lock
6148 * while we're moving its pages to another memcg. Then wait
6149 * for already started RCU-only updates to finish.
6151 atomic_inc(&mc.from->moving_account);
6154 if (unlikely(!mmap_read_trylock(mc.mm))) {
6156 * Someone who are holding the mmap_lock might be waiting in
6157 * waitq. So we cancel all extra charges, wake up all waiters,
6158 * and retry. Because we cancel precharges, we might not be able
6159 * to move enough charges, but moving charge is a best-effort
6160 * feature anyway, so it wouldn't be a big problem.
6162 __mem_cgroup_clear_mc();
6167 * When we have consumed all precharges and failed in doing
6168 * additional charge, the page walk just aborts.
6170 walk_page_range(mc.mm, 0, mc.mm->highest_vm_end, &charge_walk_ops,
6173 mmap_read_unlock(mc.mm);
6174 atomic_dec(&mc.from->moving_account);
6177 static void mem_cgroup_move_task(void)
6180 mem_cgroup_move_charge();
6181 mem_cgroup_clear_mc();
6184 #else /* !CONFIG_MMU */
6185 static int mem_cgroup_can_attach(struct cgroup_taskset *tset)
6189 static void mem_cgroup_cancel_attach(struct cgroup_taskset *tset)
6192 static void mem_cgroup_move_task(void)
6197 static int seq_puts_memcg_tunable(struct seq_file *m, unsigned long value)
6199 if (value == PAGE_COUNTER_MAX)
6200 seq_puts(m, "max\n");
6202 seq_printf(m, "%llu\n", (u64)value * PAGE_SIZE);
6207 static u64 memory_current_read(struct cgroup_subsys_state *css,
6210 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
6212 return (u64)page_counter_read(&memcg->memory) * PAGE_SIZE;
6215 static int memory_min_show(struct seq_file *m, void *v)
6217 return seq_puts_memcg_tunable(m,
6218 READ_ONCE(mem_cgroup_from_seq(m)->memory.min));
6221 static ssize_t memory_min_write(struct kernfs_open_file *of,
6222 char *buf, size_t nbytes, loff_t off)
6224 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
6228 buf = strstrip(buf);
6229 err = page_counter_memparse(buf, "max", &min);
6233 page_counter_set_min(&memcg->memory, min);
6238 static int memory_low_show(struct seq_file *m, void *v)
6240 return seq_puts_memcg_tunable(m,
6241 READ_ONCE(mem_cgroup_from_seq(m)->memory.low));
6244 static ssize_t memory_low_write(struct kernfs_open_file *of,
6245 char *buf, size_t nbytes, loff_t off)
6247 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
6251 buf = strstrip(buf);
6252 err = page_counter_memparse(buf, "max", &low);
6256 page_counter_set_low(&memcg->memory, low);
6261 static int memory_high_show(struct seq_file *m, void *v)
6263 return seq_puts_memcg_tunable(m,
6264 READ_ONCE(mem_cgroup_from_seq(m)->memory.high));
6267 static ssize_t memory_high_write(struct kernfs_open_file *of,
6268 char *buf, size_t nbytes, loff_t off)
6270 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
6271 unsigned int nr_retries = MAX_RECLAIM_RETRIES;
6272 bool drained = false;
6276 buf = strstrip(buf);
6277 err = page_counter_memparse(buf, "max", &high);
6281 page_counter_set_high(&memcg->memory, high);
6284 unsigned long nr_pages = page_counter_read(&memcg->memory);
6285 unsigned long reclaimed;
6287 if (nr_pages <= high)
6290 if (signal_pending(current))
6294 drain_all_stock(memcg);
6299 reclaimed = try_to_free_mem_cgroup_pages(memcg, nr_pages - high,
6302 if (!reclaimed && !nr_retries--)
6306 memcg_wb_domain_size_changed(memcg);
6310 static int memory_max_show(struct seq_file *m, void *v)
6312 return seq_puts_memcg_tunable(m,
6313 READ_ONCE(mem_cgroup_from_seq(m)->memory.max));
6316 static ssize_t memory_max_write(struct kernfs_open_file *of,
6317 char *buf, size_t nbytes, loff_t off)
6319 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
6320 unsigned int nr_reclaims = MAX_RECLAIM_RETRIES;
6321 bool drained = false;
6325 buf = strstrip(buf);
6326 err = page_counter_memparse(buf, "max", &max);
6330 xchg(&memcg->memory.max, max);
6333 unsigned long nr_pages = page_counter_read(&memcg->memory);
6335 if (nr_pages <= max)
6338 if (signal_pending(current))
6342 drain_all_stock(memcg);
6348 if (!try_to_free_mem_cgroup_pages(memcg, nr_pages - max,
6354 memcg_memory_event(memcg, MEMCG_OOM);
6355 if (!mem_cgroup_out_of_memory(memcg, GFP_KERNEL, 0))
6359 memcg_wb_domain_size_changed(memcg);
6363 static void __memory_events_show(struct seq_file *m, atomic_long_t *events)
6365 seq_printf(m, "low %lu\n", atomic_long_read(&events[MEMCG_LOW]));
6366 seq_printf(m, "high %lu\n", atomic_long_read(&events[MEMCG_HIGH]));
6367 seq_printf(m, "max %lu\n", atomic_long_read(&events[MEMCG_MAX]));
6368 seq_printf(m, "oom %lu\n", atomic_long_read(&events[MEMCG_OOM]));
6369 seq_printf(m, "oom_kill %lu\n",
6370 atomic_long_read(&events[MEMCG_OOM_KILL]));
6373 static int memory_events_show(struct seq_file *m, void *v)
6375 struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
6377 __memory_events_show(m, memcg->memory_events);
6381 static int memory_events_local_show(struct seq_file *m, void *v)
6383 struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
6385 __memory_events_show(m, memcg->memory_events_local);
6389 static int memory_stat_show(struct seq_file *m, void *v)
6391 struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
6394 buf = memory_stat_format(memcg);
6403 static inline unsigned long lruvec_page_state_output(struct lruvec *lruvec,
6406 return lruvec_page_state(lruvec, item) * memcg_page_state_unit(item);
6409 static int memory_numa_stat_show(struct seq_file *m, void *v)
6412 struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
6414 mem_cgroup_flush_stats();
6416 for (i = 0; i < ARRAY_SIZE(memory_stats); i++) {
6419 if (memory_stats[i].idx >= NR_VM_NODE_STAT_ITEMS)
6422 seq_printf(m, "%s", memory_stats[i].name);
6423 for_each_node_state(nid, N_MEMORY) {
6425 struct lruvec *lruvec;
6427 lruvec = mem_cgroup_lruvec(memcg, NODE_DATA(nid));
6428 size = lruvec_page_state_output(lruvec,
6429 memory_stats[i].idx);
6430 seq_printf(m, " N%d=%llu", nid, size);
6439 static int memory_oom_group_show(struct seq_file *m, void *v)
6441 struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
6443 seq_printf(m, "%d\n", memcg->oom_group);
6448 static ssize_t memory_oom_group_write(struct kernfs_open_file *of,
6449 char *buf, size_t nbytes, loff_t off)
6451 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
6454 buf = strstrip(buf);
6458 ret = kstrtoint(buf, 0, &oom_group);
6462 if (oom_group != 0 && oom_group != 1)
6465 memcg->oom_group = oom_group;
6470 static struct cftype memory_files[] = {
6473 .flags = CFTYPE_NOT_ON_ROOT,
6474 .read_u64 = memory_current_read,
6478 .flags = CFTYPE_NOT_ON_ROOT,
6479 .seq_show = memory_min_show,
6480 .write = memory_min_write,
6484 .flags = CFTYPE_NOT_ON_ROOT,
6485 .seq_show = memory_low_show,
6486 .write = memory_low_write,
6490 .flags = CFTYPE_NOT_ON_ROOT,
6491 .seq_show = memory_high_show,
6492 .write = memory_high_write,
6496 .flags = CFTYPE_NOT_ON_ROOT,
6497 .seq_show = memory_max_show,
6498 .write = memory_max_write,
6502 .flags = CFTYPE_NOT_ON_ROOT,
6503 .file_offset = offsetof(struct mem_cgroup, events_file),
6504 .seq_show = memory_events_show,
6507 .name = "events.local",
6508 .flags = CFTYPE_NOT_ON_ROOT,
6509 .file_offset = offsetof(struct mem_cgroup, events_local_file),
6510 .seq_show = memory_events_local_show,
6514 .seq_show = memory_stat_show,
6518 .name = "numa_stat",
6519 .seq_show = memory_numa_stat_show,
6523 .name = "oom.group",
6524 .flags = CFTYPE_NOT_ON_ROOT | CFTYPE_NS_DELEGATABLE,
6525 .seq_show = memory_oom_group_show,
6526 .write = memory_oom_group_write,
6531 struct cgroup_subsys memory_cgrp_subsys = {
6532 .css_alloc = mem_cgroup_css_alloc,
6533 .css_online = mem_cgroup_css_online,
6534 .css_offline = mem_cgroup_css_offline,
6535 .css_released = mem_cgroup_css_released,
6536 .css_free = mem_cgroup_css_free,
6537 .css_reset = mem_cgroup_css_reset,
6538 .css_rstat_flush = mem_cgroup_css_rstat_flush,
6539 .can_attach = mem_cgroup_can_attach,
6540 .cancel_attach = mem_cgroup_cancel_attach,
6541 .post_attach = mem_cgroup_move_task,
6542 .dfl_cftypes = memory_files,
6543 .legacy_cftypes = mem_cgroup_legacy_files,
6548 * This function calculates an individual cgroup's effective
6549 * protection which is derived from its own memory.min/low, its
6550 * parent's and siblings' settings, as well as the actual memory
6551 * distribution in the tree.
6553 * The following rules apply to the effective protection values:
6555 * 1. At the first level of reclaim, effective protection is equal to
6556 * the declared protection in memory.min and memory.low.
6558 * 2. To enable safe delegation of the protection configuration, at
6559 * subsequent levels the effective protection is capped to the
6560 * parent's effective protection.
6562 * 3. To make complex and dynamic subtrees easier to configure, the
6563 * user is allowed to overcommit the declared protection at a given
6564 * level. If that is the case, the parent's effective protection is
6565 * distributed to the children in proportion to how much protection
6566 * they have declared and how much of it they are utilizing.
6568 * This makes distribution proportional, but also work-conserving:
6569 * if one cgroup claims much more protection than it uses memory,
6570 * the unused remainder is available to its siblings.
6572 * 4. Conversely, when the declared protection is undercommitted at a
6573 * given level, the distribution of the larger parental protection
6574 * budget is NOT proportional. A cgroup's protection from a sibling
6575 * is capped to its own memory.min/low setting.
6577 * 5. However, to allow protecting recursive subtrees from each other
6578 * without having to declare each individual cgroup's fixed share
6579 * of the ancestor's claim to protection, any unutilized -
6580 * "floating" - protection from up the tree is distributed in
6581 * proportion to each cgroup's *usage*. This makes the protection
6582 * neutral wrt sibling cgroups and lets them compete freely over
6583 * the shared parental protection budget, but it protects the
6584 * subtree as a whole from neighboring subtrees.
6586 * Note that 4. and 5. are not in conflict: 4. is about protecting
6587 * against immediate siblings whereas 5. is about protecting against
6588 * neighboring subtrees.
6590 static unsigned long effective_protection(unsigned long usage,
6591 unsigned long parent_usage,
6592 unsigned long setting,
6593 unsigned long parent_effective,
6594 unsigned long siblings_protected)
6596 unsigned long protected;
6599 protected = min(usage, setting);
6601 * If all cgroups at this level combined claim and use more
6602 * protection then what the parent affords them, distribute
6603 * shares in proportion to utilization.
6605 * We are using actual utilization rather than the statically
6606 * claimed protection in order to be work-conserving: claimed
6607 * but unused protection is available to siblings that would
6608 * otherwise get a smaller chunk than what they claimed.
6610 if (siblings_protected > parent_effective)
6611 return protected * parent_effective / siblings_protected;
6614 * Ok, utilized protection of all children is within what the
6615 * parent affords them, so we know whatever this child claims
6616 * and utilizes is effectively protected.
6618 * If there is unprotected usage beyond this value, reclaim
6619 * will apply pressure in proportion to that amount.
6621 * If there is unutilized protection, the cgroup will be fully
6622 * shielded from reclaim, but we do return a smaller value for
6623 * protection than what the group could enjoy in theory. This
6624 * is okay. With the overcommit distribution above, effective
6625 * protection is always dependent on how memory is actually
6626 * consumed among the siblings anyway.
6631 * If the children aren't claiming (all of) the protection
6632 * afforded to them by the parent, distribute the remainder in
6633 * proportion to the (unprotected) memory of each cgroup. That
6634 * way, cgroups that aren't explicitly prioritized wrt each
6635 * other compete freely over the allowance, but they are
6636 * collectively protected from neighboring trees.
6638 * We're using unprotected memory for the weight so that if
6639 * some cgroups DO claim explicit protection, we don't protect
6640 * the same bytes twice.
6642 * Check both usage and parent_usage against the respective
6643 * protected values. One should imply the other, but they
6644 * aren't read atomically - make sure the division is sane.
6646 if (!(cgrp_dfl_root.flags & CGRP_ROOT_MEMORY_RECURSIVE_PROT))
6648 if (parent_effective > siblings_protected &&
6649 parent_usage > siblings_protected &&
6650 usage > protected) {
6651 unsigned long unclaimed;
6653 unclaimed = parent_effective - siblings_protected;
6654 unclaimed *= usage - protected;
6655 unclaimed /= parent_usage - siblings_protected;
6664 * mem_cgroup_calculate_protection - check if memory consumption is in the normal range
6665 * @root: the top ancestor of the sub-tree being checked
6666 * @memcg: the memory cgroup to check
6668 * WARNING: This function is not stateless! It can only be used as part
6669 * of a top-down tree iteration, not for isolated queries.
6671 void mem_cgroup_calculate_protection(struct mem_cgroup *root,
6672 struct mem_cgroup *memcg)
6674 unsigned long usage, parent_usage;
6675 struct mem_cgroup *parent;
6677 if (mem_cgroup_disabled())
6681 root = root_mem_cgroup;
6684 * Effective values of the reclaim targets are ignored so they
6685 * can be stale. Have a look at mem_cgroup_protection for more
6687 * TODO: calculation should be more robust so that we do not need
6688 * that special casing.
6693 usage = page_counter_read(&memcg->memory);
6697 parent = parent_mem_cgroup(memcg);
6698 /* No parent means a non-hierarchical mode on v1 memcg */
6702 if (parent == root) {
6703 memcg->memory.emin = READ_ONCE(memcg->memory.min);
6704 memcg->memory.elow = READ_ONCE(memcg->memory.low);
6708 parent_usage = page_counter_read(&parent->memory);
6710 WRITE_ONCE(memcg->memory.emin, effective_protection(usage, parent_usage,
6711 READ_ONCE(memcg->memory.min),
6712 READ_ONCE(parent->memory.emin),
6713 atomic_long_read(&parent->memory.children_min_usage)));
6715 WRITE_ONCE(memcg->memory.elow, effective_protection(usage, parent_usage,
6716 READ_ONCE(memcg->memory.low),
6717 READ_ONCE(parent->memory.elow),
6718 atomic_long_read(&parent->memory.children_low_usage)));
6721 static int charge_memcg(struct page *page, struct mem_cgroup *memcg, gfp_t gfp)
6723 unsigned int nr_pages = thp_nr_pages(page);
6726 ret = try_charge(memcg, gfp, nr_pages);
6730 css_get(&memcg->css);
6731 commit_charge(page, memcg);
6733 local_irq_disable();
6734 mem_cgroup_charge_statistics(memcg, page, nr_pages);
6735 memcg_check_events(memcg, page);
6742 * __mem_cgroup_charge - charge a newly allocated page to a cgroup
6743 * @page: page to charge
6744 * @mm: mm context of the victim
6745 * @gfp_mask: reclaim mode
6747 * Try to charge @page to the memcg that @mm belongs to, reclaiming
6748 * pages according to @gfp_mask if necessary. if @mm is NULL, try to
6749 * charge to the active memcg.
6751 * Do not use this for pages allocated for swapin.
6753 * Returns 0 on success. Otherwise, an error code is returned.
6755 int __mem_cgroup_charge(struct page *page, struct mm_struct *mm,
6758 struct mem_cgroup *memcg;
6761 memcg = get_mem_cgroup_from_mm(mm);
6762 ret = charge_memcg(page, memcg, gfp_mask);
6763 css_put(&memcg->css);
6769 * mem_cgroup_swapin_charge_page - charge a newly allocated page for swapin
6770 * @page: page to charge
6771 * @mm: mm context of the victim
6772 * @gfp: reclaim mode
6773 * @entry: swap entry for which the page is allocated
6775 * This function charges a page allocated for swapin. Please call this before
6776 * adding the page to the swapcache.
6778 * Returns 0 on success. Otherwise, an error code is returned.
6780 int mem_cgroup_swapin_charge_page(struct page *page, struct mm_struct *mm,
6781 gfp_t gfp, swp_entry_t entry)
6783 struct mem_cgroup *memcg;
6787 if (mem_cgroup_disabled())
6790 id = lookup_swap_cgroup_id(entry);
6792 memcg = mem_cgroup_from_id(id);
6793 if (!memcg || !css_tryget_online(&memcg->css))
6794 memcg = get_mem_cgroup_from_mm(mm);
6797 ret = charge_memcg(page, memcg, gfp);
6799 css_put(&memcg->css);
6804 * mem_cgroup_swapin_uncharge_swap - uncharge swap slot
6805 * @entry: swap entry for which the page is charged
6807 * Call this function after successfully adding the charged page to swapcache.
6809 * Note: This function assumes the page for which swap slot is being uncharged
6812 void mem_cgroup_swapin_uncharge_swap(swp_entry_t entry)
6815 * Cgroup1's unified memory+swap counter has been charged with the
6816 * new swapcache page, finish the transfer by uncharging the swap
6817 * slot. The swap slot would also get uncharged when it dies, but
6818 * it can stick around indefinitely and we'd count the page twice
6821 * Cgroup2 has separate resource counters for memory and swap,
6822 * so this is a non-issue here. Memory and swap charge lifetimes
6823 * correspond 1:1 to page and swap slot lifetimes: we charge the
6824 * page to memory here, and uncharge swap when the slot is freed.
6826 if (!mem_cgroup_disabled() && do_memsw_account()) {
6828 * The swap entry might not get freed for a long time,
6829 * let's not wait for it. The page already received a
6830 * memory+swap charge, drop the swap entry duplicate.
6832 mem_cgroup_uncharge_swap(entry, 1);
6836 struct uncharge_gather {
6837 struct mem_cgroup *memcg;
6838 unsigned long nr_memory;
6839 unsigned long pgpgout;
6840 unsigned long nr_kmem;
6841 struct page *dummy_page;
6844 static inline void uncharge_gather_clear(struct uncharge_gather *ug)
6846 memset(ug, 0, sizeof(*ug));
6849 static void uncharge_batch(const struct uncharge_gather *ug)
6851 unsigned long flags;
6853 if (ug->nr_memory) {
6854 page_counter_uncharge(&ug->memcg->memory, ug->nr_memory);
6855 if (do_memsw_account())
6856 page_counter_uncharge(&ug->memcg->memsw, ug->nr_memory);
6857 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && ug->nr_kmem)
6858 page_counter_uncharge(&ug->memcg->kmem, ug->nr_kmem);
6859 memcg_oom_recover(ug->memcg);
6862 local_irq_save(flags);
6863 __count_memcg_events(ug->memcg, PGPGOUT, ug->pgpgout);
6864 __this_cpu_add(ug->memcg->vmstats_percpu->nr_page_events, ug->nr_memory);
6865 memcg_check_events(ug->memcg, ug->dummy_page);
6866 local_irq_restore(flags);
6868 /* drop reference from uncharge_page */
6869 css_put(&ug->memcg->css);
6872 static void uncharge_page(struct page *page, struct uncharge_gather *ug)
6874 unsigned long nr_pages;
6875 struct mem_cgroup *memcg;
6876 struct obj_cgroup *objcg;
6877 bool use_objcg = PageMemcgKmem(page);
6879 VM_BUG_ON_PAGE(PageLRU(page), page);
6882 * Nobody should be changing or seriously looking at
6883 * page memcg or objcg at this point, we have fully
6884 * exclusive access to the page.
6887 objcg = __page_objcg(page);
6889 * This get matches the put at the end of the function and
6890 * kmem pages do not hold memcg references anymore.
6892 memcg = get_mem_cgroup_from_objcg(objcg);
6894 memcg = __page_memcg(page);
6900 if (ug->memcg != memcg) {
6903 uncharge_gather_clear(ug);
6906 ug->dummy_page = page;
6908 /* pairs with css_put in uncharge_batch */
6909 css_get(&memcg->css);
6912 nr_pages = compound_nr(page);
6915 ug->nr_memory += nr_pages;
6916 ug->nr_kmem += nr_pages;
6918 page->memcg_data = 0;
6919 obj_cgroup_put(objcg);
6921 /* LRU pages aren't accounted at the root level */
6922 if (!mem_cgroup_is_root(memcg))
6923 ug->nr_memory += nr_pages;
6926 page->memcg_data = 0;
6929 css_put(&memcg->css);
6933 * __mem_cgroup_uncharge - uncharge a page
6934 * @page: page to uncharge
6936 * Uncharge a page previously charged with __mem_cgroup_charge().
6938 void __mem_cgroup_uncharge(struct page *page)
6940 struct uncharge_gather ug;
6942 /* Don't touch page->lru of any random page, pre-check: */
6943 if (!page_memcg(page))
6946 uncharge_gather_clear(&ug);
6947 uncharge_page(page, &ug);
6948 uncharge_batch(&ug);
6952 * __mem_cgroup_uncharge_list - uncharge a list of page
6953 * @page_list: list of pages to uncharge
6955 * Uncharge a list of pages previously charged with
6956 * __mem_cgroup_charge().
6958 void __mem_cgroup_uncharge_list(struct list_head *page_list)
6960 struct uncharge_gather ug;
6963 uncharge_gather_clear(&ug);
6964 list_for_each_entry(page, page_list, lru)
6965 uncharge_page(page, &ug);
6967 uncharge_batch(&ug);
6971 * mem_cgroup_migrate - charge a page's replacement
6972 * @oldpage: currently circulating page
6973 * @newpage: replacement page
6975 * Charge @newpage as a replacement page for @oldpage. @oldpage will
6976 * be uncharged upon free.
6978 * Both pages must be locked, @newpage->mapping must be set up.
6980 void mem_cgroup_migrate(struct page *oldpage, struct page *newpage)
6982 struct mem_cgroup *memcg;
6983 unsigned int nr_pages;
6984 unsigned long flags;
6986 VM_BUG_ON_PAGE(!PageLocked(oldpage), oldpage);
6987 VM_BUG_ON_PAGE(!PageLocked(newpage), newpage);
6988 VM_BUG_ON_PAGE(PageAnon(oldpage) != PageAnon(newpage), newpage);
6989 VM_BUG_ON_PAGE(PageTransHuge(oldpage) != PageTransHuge(newpage),
6992 if (mem_cgroup_disabled())
6995 /* Page cache replacement: new page already charged? */
6996 if (page_memcg(newpage))
6999 memcg = page_memcg(oldpage);
7000 VM_WARN_ON_ONCE_PAGE(!memcg, oldpage);
7004 /* Force-charge the new page. The old one will be freed soon */
7005 nr_pages = thp_nr_pages(newpage);
7007 if (!mem_cgroup_is_root(memcg)) {
7008 page_counter_charge(&memcg->memory, nr_pages);
7009 if (do_memsw_account())
7010 page_counter_charge(&memcg->memsw, nr_pages);
7013 css_get(&memcg->css);
7014 commit_charge(newpage, memcg);
7016 local_irq_save(flags);
7017 mem_cgroup_charge_statistics(memcg, newpage, nr_pages);
7018 memcg_check_events(memcg, newpage);
7019 local_irq_restore(flags);
7022 DEFINE_STATIC_KEY_FALSE(memcg_sockets_enabled_key);
7023 EXPORT_SYMBOL(memcg_sockets_enabled_key);
7025 void mem_cgroup_sk_alloc(struct sock *sk)
7027 struct mem_cgroup *memcg;
7029 if (!mem_cgroup_sockets_enabled)
7032 /* Do not associate the sock with unrelated interrupted task's memcg. */
7037 memcg = mem_cgroup_from_task(current);
7038 if (memcg == root_mem_cgroup)
7040 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && !memcg->tcpmem_active)
7042 if (css_tryget(&memcg->css))
7043 sk->sk_memcg = memcg;
7048 void mem_cgroup_sk_free(struct sock *sk)
7051 css_put(&sk->sk_memcg->css);
7055 * mem_cgroup_charge_skmem - charge socket memory
7056 * @memcg: memcg to charge
7057 * @nr_pages: number of pages to charge
7058 * @gfp_mask: reclaim mode
7060 * Charges @nr_pages to @memcg. Returns %true if the charge fit within
7061 * @memcg's configured limit, %false if it doesn't.
7063 bool mem_cgroup_charge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages,
7066 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) {
7067 struct page_counter *fail;
7069 if (page_counter_try_charge(&memcg->tcpmem, nr_pages, &fail)) {
7070 memcg->tcpmem_pressure = 0;
7073 memcg->tcpmem_pressure = 1;
7074 if (gfp_mask & __GFP_NOFAIL) {
7075 page_counter_charge(&memcg->tcpmem, nr_pages);
7081 if (try_charge(memcg, gfp_mask, nr_pages) == 0) {
7082 mod_memcg_state(memcg, MEMCG_SOCK, nr_pages);
7090 * mem_cgroup_uncharge_skmem - uncharge socket memory
7091 * @memcg: memcg to uncharge
7092 * @nr_pages: number of pages to uncharge
7094 void mem_cgroup_uncharge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages)
7096 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) {
7097 page_counter_uncharge(&memcg->tcpmem, nr_pages);
7101 mod_memcg_state(memcg, MEMCG_SOCK, -nr_pages);
7103 refill_stock(memcg, nr_pages);
7106 static int __init cgroup_memory(char *s)
7110 while ((token = strsep(&s, ",")) != NULL) {
7113 if (!strcmp(token, "nosocket"))
7114 cgroup_memory_nosocket = true;
7115 if (!strcmp(token, "nokmem"))
7116 cgroup_memory_nokmem = true;
7120 __setup("cgroup.memory=", cgroup_memory);
7123 * subsys_initcall() for memory controller.
7125 * Some parts like memcg_hotplug_cpu_dead() have to be initialized from this
7126 * context because of lock dependencies (cgroup_lock -> cpu hotplug) but
7127 * basically everything that doesn't depend on a specific mem_cgroup structure
7128 * should be initialized from here.
7130 static int __init mem_cgroup_init(void)
7135 * Currently s32 type (can refer to struct batched_lruvec_stat) is
7136 * used for per-memcg-per-cpu caching of per-node statistics. In order
7137 * to work fine, we should make sure that the overfill threshold can't
7138 * exceed S32_MAX / PAGE_SIZE.
7140 BUILD_BUG_ON(MEMCG_CHARGE_BATCH > S32_MAX / PAGE_SIZE);
7142 cpuhp_setup_state_nocalls(CPUHP_MM_MEMCQ_DEAD, "mm/memctrl:dead", NULL,
7143 memcg_hotplug_cpu_dead);
7145 for_each_possible_cpu(cpu)
7146 INIT_WORK(&per_cpu_ptr(&memcg_stock, cpu)->work,
7149 for_each_node(node) {
7150 struct mem_cgroup_tree_per_node *rtpn;
7152 rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL,
7153 node_online(node) ? node : NUMA_NO_NODE);
7155 rtpn->rb_root = RB_ROOT;
7156 rtpn->rb_rightmost = NULL;
7157 spin_lock_init(&rtpn->lock);
7158 soft_limit_tree.rb_tree_per_node[node] = rtpn;
7163 subsys_initcall(mem_cgroup_init);
7165 #ifdef CONFIG_MEMCG_SWAP
7166 static struct mem_cgroup *mem_cgroup_id_get_online(struct mem_cgroup *memcg)
7168 while (!refcount_inc_not_zero(&memcg->id.ref)) {
7170 * The root cgroup cannot be destroyed, so it's refcount must
7173 if (WARN_ON_ONCE(memcg == root_mem_cgroup)) {
7177 memcg = parent_mem_cgroup(memcg);
7179 memcg = root_mem_cgroup;
7185 * mem_cgroup_swapout - transfer a memsw charge to swap
7186 * @page: page whose memsw charge to transfer
7187 * @entry: swap entry to move the charge to
7189 * Transfer the memsw charge of @page to @entry.
7191 void mem_cgroup_swapout(struct page *page, swp_entry_t entry)
7193 struct mem_cgroup *memcg, *swap_memcg;
7194 unsigned int nr_entries;
7195 unsigned short oldid;
7197 VM_BUG_ON_PAGE(PageLRU(page), page);
7198 VM_BUG_ON_PAGE(page_count(page), page);
7200 if (mem_cgroup_disabled())
7203 if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
7206 memcg = page_memcg(page);
7208 VM_WARN_ON_ONCE_PAGE(!memcg, page);
7213 * In case the memcg owning these pages has been offlined and doesn't
7214 * have an ID allocated to it anymore, charge the closest online
7215 * ancestor for the swap instead and transfer the memory+swap charge.
7217 swap_memcg = mem_cgroup_id_get_online(memcg);
7218 nr_entries = thp_nr_pages(page);
7219 /* Get references for the tail pages, too */
7221 mem_cgroup_id_get_many(swap_memcg, nr_entries - 1);
7222 oldid = swap_cgroup_record(entry, mem_cgroup_id(swap_memcg),
7224 VM_BUG_ON_PAGE(oldid, page);
7225 mod_memcg_state(swap_memcg, MEMCG_SWAP, nr_entries);
7227 page->memcg_data = 0;
7229 if (!mem_cgroup_is_root(memcg))
7230 page_counter_uncharge(&memcg->memory, nr_entries);
7232 if (!cgroup_memory_noswap && memcg != swap_memcg) {
7233 if (!mem_cgroup_is_root(swap_memcg))
7234 page_counter_charge(&swap_memcg->memsw, nr_entries);
7235 page_counter_uncharge(&memcg->memsw, nr_entries);
7239 * Interrupts should be disabled here because the caller holds the
7240 * i_pages lock which is taken with interrupts-off. It is
7241 * important here to have the interrupts disabled because it is the
7242 * only synchronisation we have for updating the per-CPU variables.
7244 VM_BUG_ON(!irqs_disabled());
7245 mem_cgroup_charge_statistics(memcg, page, -nr_entries);
7246 memcg_check_events(memcg, page);
7248 css_put(&memcg->css);
7252 * __mem_cgroup_try_charge_swap - try charging swap space for a page
7253 * @page: page being added to swap
7254 * @entry: swap entry to charge
7256 * Try to charge @page's memcg for the swap space at @entry.
7258 * Returns 0 on success, -ENOMEM on failure.
7260 int __mem_cgroup_try_charge_swap(struct page *page, swp_entry_t entry)
7262 unsigned int nr_pages = thp_nr_pages(page);
7263 struct page_counter *counter;
7264 struct mem_cgroup *memcg;
7265 unsigned short oldid;
7267 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys))
7270 memcg = page_memcg(page);
7272 VM_WARN_ON_ONCE_PAGE(!memcg, page);
7277 memcg_memory_event(memcg, MEMCG_SWAP_FAIL);
7281 memcg = mem_cgroup_id_get_online(memcg);
7283 if (!cgroup_memory_noswap && !mem_cgroup_is_root(memcg) &&
7284 !page_counter_try_charge(&memcg->swap, nr_pages, &counter)) {
7285 memcg_memory_event(memcg, MEMCG_SWAP_MAX);
7286 memcg_memory_event(memcg, MEMCG_SWAP_FAIL);
7287 mem_cgroup_id_put(memcg);
7291 /* Get references for the tail pages, too */
7293 mem_cgroup_id_get_many(memcg, nr_pages - 1);
7294 oldid = swap_cgroup_record(entry, mem_cgroup_id(memcg), nr_pages);
7295 VM_BUG_ON_PAGE(oldid, page);
7296 mod_memcg_state(memcg, MEMCG_SWAP, nr_pages);
7302 * __mem_cgroup_uncharge_swap - uncharge swap space
7303 * @entry: swap entry to uncharge
7304 * @nr_pages: the amount of swap space to uncharge
7306 void __mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages)
7308 struct mem_cgroup *memcg;
7311 id = swap_cgroup_record(entry, 0, nr_pages);
7313 memcg = mem_cgroup_from_id(id);
7315 if (!cgroup_memory_noswap && !mem_cgroup_is_root(memcg)) {
7316 if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
7317 page_counter_uncharge(&memcg->swap, nr_pages);
7319 page_counter_uncharge(&memcg->memsw, nr_pages);
7321 mod_memcg_state(memcg, MEMCG_SWAP, -nr_pages);
7322 mem_cgroup_id_put_many(memcg, nr_pages);
7327 long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg)
7329 long nr_swap_pages = get_nr_swap_pages();
7331 if (cgroup_memory_noswap || !cgroup_subsys_on_dfl(memory_cgrp_subsys))
7332 return nr_swap_pages;
7333 for (; memcg != root_mem_cgroup; memcg = parent_mem_cgroup(memcg))
7334 nr_swap_pages = min_t(long, nr_swap_pages,
7335 READ_ONCE(memcg->swap.max) -
7336 page_counter_read(&memcg->swap));
7337 return nr_swap_pages;
7340 bool mem_cgroup_swap_full(struct page *page)
7342 struct mem_cgroup *memcg;
7344 VM_BUG_ON_PAGE(!PageLocked(page), page);
7348 if (cgroup_memory_noswap || !cgroup_subsys_on_dfl(memory_cgrp_subsys))
7351 memcg = page_memcg(page);
7355 for (; memcg != root_mem_cgroup; memcg = parent_mem_cgroup(memcg)) {
7356 unsigned long usage = page_counter_read(&memcg->swap);
7358 if (usage * 2 >= READ_ONCE(memcg->swap.high) ||
7359 usage * 2 >= READ_ONCE(memcg->swap.max))
7366 static int __init setup_swap_account(char *s)
7368 if (!strcmp(s, "1"))
7369 cgroup_memory_noswap = false;
7370 else if (!strcmp(s, "0"))
7371 cgroup_memory_noswap = true;
7374 __setup("swapaccount=", setup_swap_account);
7376 static u64 swap_current_read(struct cgroup_subsys_state *css,
7379 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
7381 return (u64)page_counter_read(&memcg->swap) * PAGE_SIZE;
7384 static int swap_high_show(struct seq_file *m, void *v)
7386 return seq_puts_memcg_tunable(m,
7387 READ_ONCE(mem_cgroup_from_seq(m)->swap.high));
7390 static ssize_t swap_high_write(struct kernfs_open_file *of,
7391 char *buf, size_t nbytes, loff_t off)
7393 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
7397 buf = strstrip(buf);
7398 err = page_counter_memparse(buf, "max", &high);
7402 page_counter_set_high(&memcg->swap, high);
7407 static int swap_max_show(struct seq_file *m, void *v)
7409 return seq_puts_memcg_tunable(m,
7410 READ_ONCE(mem_cgroup_from_seq(m)->swap.max));
7413 static ssize_t swap_max_write(struct kernfs_open_file *of,
7414 char *buf, size_t nbytes, loff_t off)
7416 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
7420 buf = strstrip(buf);
7421 err = page_counter_memparse(buf, "max", &max);
7425 xchg(&memcg->swap.max, max);
7430 static int swap_events_show(struct seq_file *m, void *v)
7432 struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
7434 seq_printf(m, "high %lu\n",
7435 atomic_long_read(&memcg->memory_events[MEMCG_SWAP_HIGH]));
7436 seq_printf(m, "max %lu\n",
7437 atomic_long_read(&memcg->memory_events[MEMCG_SWAP_MAX]));
7438 seq_printf(m, "fail %lu\n",
7439 atomic_long_read(&memcg->memory_events[MEMCG_SWAP_FAIL]));
7444 static struct cftype swap_files[] = {
7446 .name = "swap.current",
7447 .flags = CFTYPE_NOT_ON_ROOT,
7448 .read_u64 = swap_current_read,
7451 .name = "swap.high",
7452 .flags = CFTYPE_NOT_ON_ROOT,
7453 .seq_show = swap_high_show,
7454 .write = swap_high_write,
7458 .flags = CFTYPE_NOT_ON_ROOT,
7459 .seq_show = swap_max_show,
7460 .write = swap_max_write,
7463 .name = "swap.events",
7464 .flags = CFTYPE_NOT_ON_ROOT,
7465 .file_offset = offsetof(struct mem_cgroup, swap_events_file),
7466 .seq_show = swap_events_show,
7471 static struct cftype memsw_files[] = {
7473 .name = "memsw.usage_in_bytes",
7474 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE),
7475 .read_u64 = mem_cgroup_read_u64,
7478 .name = "memsw.max_usage_in_bytes",
7479 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE),
7480 .write = mem_cgroup_reset,
7481 .read_u64 = mem_cgroup_read_u64,
7484 .name = "memsw.limit_in_bytes",
7485 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT),
7486 .write = mem_cgroup_write,
7487 .read_u64 = mem_cgroup_read_u64,
7490 .name = "memsw.failcnt",
7491 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT),
7492 .write = mem_cgroup_reset,
7493 .read_u64 = mem_cgroup_read_u64,
7495 { }, /* terminate */
7499 * If mem_cgroup_swap_init() is implemented as a subsys_initcall()
7500 * instead of a core_initcall(), this could mean cgroup_memory_noswap still
7501 * remains set to false even when memcg is disabled via "cgroup_disable=memory"
7502 * boot parameter. This may result in premature OOPS inside
7503 * mem_cgroup_get_nr_swap_pages() function in corner cases.
7505 static int __init mem_cgroup_swap_init(void)
7507 /* No memory control -> no swap control */
7508 if (mem_cgroup_disabled())
7509 cgroup_memory_noswap = true;
7511 if (cgroup_memory_noswap)
7514 WARN_ON(cgroup_add_dfl_cftypes(&memory_cgrp_subsys, swap_files));
7515 WARN_ON(cgroup_add_legacy_cftypes(&memory_cgrp_subsys, memsw_files));
7519 core_initcall(mem_cgroup_swap_init);
7521 #endif /* CONFIG_MEMCG_SWAP */