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/memremap.h>
57 #include <linux/mm_inline.h>
58 #include <linux/swap_cgroup.h>
59 #include <linux/cpu.h>
60 #include <linux/oom.h>
61 #include <linux/lockdep.h>
62 #include <linux/file.h>
63 #include <linux/resume_user_mode.h>
64 #include <linux/psi.h>
65 #include <linux/seq_buf.h>
66 #include <linux/sched/isolation.h>
67 #include <linux/kmemleak.h>
74 #include <linux/uaccess.h>
76 #include <trace/events/vmscan.h>
78 struct cgroup_subsys memory_cgrp_subsys __read_mostly;
79 EXPORT_SYMBOL(memory_cgrp_subsys);
81 struct mem_cgroup *root_mem_cgroup __read_mostly;
83 /* Active memory cgroup to use from an interrupt context */
84 DEFINE_PER_CPU(struct mem_cgroup *, int_active_memcg);
85 EXPORT_PER_CPU_SYMBOL_GPL(int_active_memcg);
87 /* Socket memory accounting disabled? */
88 static bool cgroup_memory_nosocket __ro_after_init;
90 /* Kernel memory accounting disabled? */
91 static bool cgroup_memory_nokmem __ro_after_init;
93 /* BPF memory accounting disabled? */
94 static bool cgroup_memory_nobpf __ro_after_init;
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);
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_soft_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 */
215 #define MEMFILE_PRIVATE(x, val) ((x) << 16 | (val))
216 #define MEMFILE_TYPE(val) ((val) >> 16 & 0xffff)
217 #define MEMFILE_ATTR(val) ((val) & 0xffff)
220 * Iteration constructs for visiting all cgroups (under a tree). If
221 * loops are exited prematurely (break), mem_cgroup_iter_break() must
222 * be used for reference counting.
224 #define for_each_mem_cgroup_tree(iter, root) \
225 for (iter = mem_cgroup_iter(root, NULL, NULL); \
227 iter = mem_cgroup_iter(root, iter, NULL))
229 #define for_each_mem_cgroup(iter) \
230 for (iter = mem_cgroup_iter(NULL, NULL, NULL); \
232 iter = mem_cgroup_iter(NULL, iter, NULL))
234 static inline bool task_is_dying(void)
236 return tsk_is_oom_victim(current) || fatal_signal_pending(current) ||
237 (current->flags & PF_EXITING);
240 /* Some nice accessors for the vmpressure. */
241 struct vmpressure *memcg_to_vmpressure(struct mem_cgroup *memcg)
244 memcg = root_mem_cgroup;
245 return &memcg->vmpressure;
248 struct mem_cgroup *vmpressure_to_memcg(struct vmpressure *vmpr)
250 return container_of(vmpr, struct mem_cgroup, vmpressure);
253 #define CURRENT_OBJCG_UPDATE_BIT 0
254 #define CURRENT_OBJCG_UPDATE_FLAG (1UL << CURRENT_OBJCG_UPDATE_BIT)
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 * A lot of the calls to the cache allocation functions are expected to be
352 * inlined by the compiler. Since the calls to memcg_slab_pre_alloc_hook() are
353 * conditional to this static branch, we'll have to allow modules that does
354 * kmem_cache_alloc and the such to see this symbol as well
356 DEFINE_STATIC_KEY_FALSE(memcg_kmem_online_key);
357 EXPORT_SYMBOL(memcg_kmem_online_key);
359 DEFINE_STATIC_KEY_FALSE(memcg_bpf_enabled_key);
360 EXPORT_SYMBOL(memcg_bpf_enabled_key);
364 * mem_cgroup_css_from_folio - css of the memcg associated with a folio
365 * @folio: folio of interest
367 * If memcg is bound to the default hierarchy, css of the memcg associated
368 * with @folio is returned. The returned css remains associated with @folio
369 * until it is released.
371 * If memcg is bound to a traditional hierarchy, the css of root_mem_cgroup
374 struct cgroup_subsys_state *mem_cgroup_css_from_folio(struct folio *folio)
376 struct mem_cgroup *memcg = folio_memcg(folio);
378 if (!memcg || !cgroup_subsys_on_dfl(memory_cgrp_subsys))
379 memcg = root_mem_cgroup;
385 * page_cgroup_ino - return inode number of the memcg a page is charged to
388 * Look up the closest online ancestor of the memory cgroup @page is charged to
389 * and return its inode number or 0 if @page is not charged to any cgroup. It
390 * is safe to call this function without holding a reference to @page.
392 * Note, this function is inherently racy, because there is nothing to prevent
393 * the cgroup inode from getting torn down and potentially reallocated a moment
394 * after page_cgroup_ino() returns, so it only should be used by callers that
395 * do not care (such as procfs interfaces).
397 ino_t page_cgroup_ino(struct page *page)
399 struct mem_cgroup *memcg;
400 unsigned long ino = 0;
403 /* page_folio() is racy here, but the entire function is racy anyway */
404 memcg = folio_memcg_check(page_folio(page));
406 while (memcg && !(memcg->css.flags & CSS_ONLINE))
407 memcg = parent_mem_cgroup(memcg);
409 ino = cgroup_ino(memcg->css.cgroup);
414 static void __mem_cgroup_insert_exceeded(struct mem_cgroup_per_node *mz,
415 struct mem_cgroup_tree_per_node *mctz,
416 unsigned long new_usage_in_excess)
418 struct rb_node **p = &mctz->rb_root.rb_node;
419 struct rb_node *parent = NULL;
420 struct mem_cgroup_per_node *mz_node;
421 bool rightmost = true;
426 mz->usage_in_excess = new_usage_in_excess;
427 if (!mz->usage_in_excess)
431 mz_node = rb_entry(parent, struct mem_cgroup_per_node,
433 if (mz->usage_in_excess < mz_node->usage_in_excess) {
442 mctz->rb_rightmost = &mz->tree_node;
444 rb_link_node(&mz->tree_node, parent, p);
445 rb_insert_color(&mz->tree_node, &mctz->rb_root);
449 static void __mem_cgroup_remove_exceeded(struct mem_cgroup_per_node *mz,
450 struct mem_cgroup_tree_per_node *mctz)
455 if (&mz->tree_node == mctz->rb_rightmost)
456 mctz->rb_rightmost = rb_prev(&mz->tree_node);
458 rb_erase(&mz->tree_node, &mctz->rb_root);
462 static void mem_cgroup_remove_exceeded(struct mem_cgroup_per_node *mz,
463 struct mem_cgroup_tree_per_node *mctz)
467 spin_lock_irqsave(&mctz->lock, flags);
468 __mem_cgroup_remove_exceeded(mz, mctz);
469 spin_unlock_irqrestore(&mctz->lock, flags);
472 static unsigned long soft_limit_excess(struct mem_cgroup *memcg)
474 unsigned long nr_pages = page_counter_read(&memcg->memory);
475 unsigned long soft_limit = READ_ONCE(memcg->soft_limit);
476 unsigned long excess = 0;
478 if (nr_pages > soft_limit)
479 excess = nr_pages - soft_limit;
484 static void mem_cgroup_update_tree(struct mem_cgroup *memcg, int nid)
486 unsigned long excess;
487 struct mem_cgroup_per_node *mz;
488 struct mem_cgroup_tree_per_node *mctz;
490 if (lru_gen_enabled()) {
491 if (soft_limit_excess(memcg))
492 lru_gen_soft_reclaim(memcg, nid);
496 mctz = soft_limit_tree.rb_tree_per_node[nid];
500 * Necessary to update all ancestors when hierarchy is used.
501 * because their event counter is not touched.
503 for (; memcg; memcg = parent_mem_cgroup(memcg)) {
504 mz = memcg->nodeinfo[nid];
505 excess = soft_limit_excess(memcg);
507 * We have to update the tree if mz is on RB-tree or
508 * mem is over its softlimit.
510 if (excess || mz->on_tree) {
513 spin_lock_irqsave(&mctz->lock, flags);
514 /* if on-tree, remove it */
516 __mem_cgroup_remove_exceeded(mz, mctz);
518 * Insert again. mz->usage_in_excess will be updated.
519 * If excess is 0, no tree ops.
521 __mem_cgroup_insert_exceeded(mz, mctz, excess);
522 spin_unlock_irqrestore(&mctz->lock, flags);
527 static void mem_cgroup_remove_from_trees(struct mem_cgroup *memcg)
529 struct mem_cgroup_tree_per_node *mctz;
530 struct mem_cgroup_per_node *mz;
534 mz = memcg->nodeinfo[nid];
535 mctz = soft_limit_tree.rb_tree_per_node[nid];
537 mem_cgroup_remove_exceeded(mz, mctz);
541 static struct mem_cgroup_per_node *
542 __mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_node *mctz)
544 struct mem_cgroup_per_node *mz;
548 if (!mctz->rb_rightmost)
549 goto done; /* Nothing to reclaim from */
551 mz = rb_entry(mctz->rb_rightmost,
552 struct mem_cgroup_per_node, tree_node);
554 * Remove the node now but someone else can add it back,
555 * we will to add it back at the end of reclaim to its correct
556 * position in the tree.
558 __mem_cgroup_remove_exceeded(mz, mctz);
559 if (!soft_limit_excess(mz->memcg) ||
560 !css_tryget(&mz->memcg->css))
566 static struct mem_cgroup_per_node *
567 mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_node *mctz)
569 struct mem_cgroup_per_node *mz;
571 spin_lock_irq(&mctz->lock);
572 mz = __mem_cgroup_largest_soft_limit_node(mctz);
573 spin_unlock_irq(&mctz->lock);
577 /* Subset of vm_event_item to report for memcg event stats */
578 static const unsigned int memcg_vm_event_stat[] = {
594 #if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_ZSWAP)
599 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
607 #define NR_MEMCG_EVENTS ARRAY_SIZE(memcg_vm_event_stat)
608 static int mem_cgroup_events_index[NR_VM_EVENT_ITEMS] __read_mostly;
610 static void init_memcg_events(void)
614 for (i = 0; i < NR_MEMCG_EVENTS; ++i)
615 mem_cgroup_events_index[memcg_vm_event_stat[i]] = i + 1;
618 static inline int memcg_events_index(enum vm_event_item idx)
620 return mem_cgroup_events_index[idx] - 1;
623 struct memcg_vmstats_percpu {
624 /* Stats updates since the last flush */
625 unsigned int stats_updates;
627 /* Cached pointers for fast iteration in memcg_rstat_updated() */
628 struct memcg_vmstats_percpu *parent;
629 struct memcg_vmstats *vmstats;
631 /* The above should fit a single cacheline for memcg_rstat_updated() */
633 /* Local (CPU and cgroup) page state & events */
634 long state[MEMCG_NR_STAT];
635 unsigned long events[NR_MEMCG_EVENTS];
637 /* Delta calculation for lockless upward propagation */
638 long state_prev[MEMCG_NR_STAT];
639 unsigned long events_prev[NR_MEMCG_EVENTS];
641 /* Cgroup1: threshold notifications & softlimit tree updates */
642 unsigned long nr_page_events;
643 unsigned long targets[MEM_CGROUP_NTARGETS];
644 } ____cacheline_aligned;
646 struct memcg_vmstats {
647 /* Aggregated (CPU and subtree) page state & events */
648 long state[MEMCG_NR_STAT];
649 unsigned long events[NR_MEMCG_EVENTS];
651 /* Non-hierarchical (CPU aggregated) page state & events */
652 long state_local[MEMCG_NR_STAT];
653 unsigned long events_local[NR_MEMCG_EVENTS];
655 /* Pending child counts during tree propagation */
656 long state_pending[MEMCG_NR_STAT];
657 unsigned long events_pending[NR_MEMCG_EVENTS];
659 /* Stats updates since the last flush */
660 atomic64_t stats_updates;
664 * memcg and lruvec stats flushing
666 * Many codepaths leading to stats update or read are performance sensitive and
667 * adding stats flushing in such codepaths is not desirable. So, to optimize the
668 * flushing the kernel does:
670 * 1) Periodically and asynchronously flush the stats every 2 seconds to not let
671 * rstat update tree grow unbounded.
673 * 2) Flush the stats synchronously on reader side only when there are more than
674 * (MEMCG_CHARGE_BATCH * nr_cpus) update events. Though this optimization
675 * will let stats be out of sync by atmost (MEMCG_CHARGE_BATCH * nr_cpus) but
676 * only for 2 seconds due to (1).
678 static void flush_memcg_stats_dwork(struct work_struct *w);
679 static DECLARE_DEFERRABLE_WORK(stats_flush_dwork, flush_memcg_stats_dwork);
680 static u64 flush_last_time;
682 #define FLUSH_TIME (2UL*HZ)
685 * Accessors to ensure that preemption is disabled on PREEMPT_RT because it can
686 * not rely on this as part of an acquired spinlock_t lock. These functions are
687 * never used in hardirq context on PREEMPT_RT and therefore disabling preemtion
690 static void memcg_stats_lock(void)
692 preempt_disable_nested();
693 VM_WARN_ON_IRQS_ENABLED();
696 static void __memcg_stats_lock(void)
698 preempt_disable_nested();
701 static void memcg_stats_unlock(void)
703 preempt_enable_nested();
707 static bool memcg_vmstats_needs_flush(struct memcg_vmstats *vmstats)
709 return atomic64_read(&vmstats->stats_updates) >
710 MEMCG_CHARGE_BATCH * num_online_cpus();
713 static inline void memcg_rstat_updated(struct mem_cgroup *memcg, int val)
715 struct memcg_vmstats_percpu *statc;
716 int cpu = smp_processor_id();
721 cgroup_rstat_updated(memcg->css.cgroup, cpu);
722 statc = this_cpu_ptr(memcg->vmstats_percpu);
723 for (; statc; statc = statc->parent) {
724 statc->stats_updates += abs(val);
725 if (statc->stats_updates < MEMCG_CHARGE_BATCH)
729 * If @memcg is already flush-able, increasing stats_updates is
730 * redundant. Avoid the overhead of the atomic update.
732 if (!memcg_vmstats_needs_flush(statc->vmstats))
733 atomic64_add(statc->stats_updates,
734 &statc->vmstats->stats_updates);
735 statc->stats_updates = 0;
739 static void do_flush_stats(struct mem_cgroup *memcg)
741 if (mem_cgroup_is_root(memcg))
742 WRITE_ONCE(flush_last_time, jiffies_64);
744 cgroup_rstat_flush(memcg->css.cgroup);
748 * mem_cgroup_flush_stats - flush the stats of a memory cgroup subtree
749 * @memcg: root of the subtree to flush
751 * Flushing is serialized by the underlying global rstat lock. There is also a
752 * minimum amount of work to be done even if there are no stat updates to flush.
753 * Hence, we only flush the stats if the updates delta exceeds a threshold. This
754 * avoids unnecessary work and contention on the underlying lock.
756 void mem_cgroup_flush_stats(struct mem_cgroup *memcg)
758 if (mem_cgroup_disabled())
762 memcg = root_mem_cgroup;
764 if (memcg_vmstats_needs_flush(memcg->vmstats))
765 do_flush_stats(memcg);
768 void mem_cgroup_flush_stats_ratelimited(struct mem_cgroup *memcg)
770 /* Only flush if the periodic flusher is one full cycle late */
771 if (time_after64(jiffies_64, READ_ONCE(flush_last_time) + 2*FLUSH_TIME))
772 mem_cgroup_flush_stats(memcg);
775 static void flush_memcg_stats_dwork(struct work_struct *w)
778 * Deliberately ignore memcg_vmstats_needs_flush() here so that flushing
779 * in latency-sensitive paths is as cheap as possible.
781 do_flush_stats(root_mem_cgroup);
782 queue_delayed_work(system_unbound_wq, &stats_flush_dwork, FLUSH_TIME);
785 unsigned long memcg_page_state(struct mem_cgroup *memcg, int idx)
787 long x = READ_ONCE(memcg->vmstats->state[idx]);
795 static int memcg_page_state_unit(int item);
798 * Normalize the value passed into memcg_rstat_updated() to be in pages. Round
799 * up non-zero sub-page updates to 1 page as zero page updates are ignored.
801 static int memcg_state_val_in_pages(int idx, int val)
803 int unit = memcg_page_state_unit(idx);
805 if (!val || unit == PAGE_SIZE)
808 return max(val * unit / PAGE_SIZE, 1UL);
812 * __mod_memcg_state - update cgroup memory statistics
813 * @memcg: the memory cgroup
814 * @idx: the stat item - can be enum memcg_stat_item or enum node_stat_item
815 * @val: delta to add to the counter, can be negative
817 void __mod_memcg_state(struct mem_cgroup *memcg, int idx, int val)
819 if (mem_cgroup_disabled())
822 __this_cpu_add(memcg->vmstats_percpu->state[idx], val);
823 memcg_rstat_updated(memcg, memcg_state_val_in_pages(idx, val));
826 /* idx can be of type enum memcg_stat_item or node_stat_item. */
827 static unsigned long memcg_page_state_local(struct mem_cgroup *memcg, int idx)
829 long x = READ_ONCE(memcg->vmstats->state_local[idx]);
838 void __mod_memcg_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx,
841 struct mem_cgroup_per_node *pn;
842 struct mem_cgroup *memcg;
844 pn = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
848 * The caller from rmap relies on disabled preemption because they never
849 * update their counter from in-interrupt context. For these two
850 * counters we check that the update is never performed from an
851 * interrupt context while other caller need to have disabled interrupt.
853 __memcg_stats_lock();
854 if (IS_ENABLED(CONFIG_DEBUG_VM)) {
859 case NR_SHMEM_PMDMAPPED:
860 case NR_FILE_PMDMAPPED:
861 WARN_ON_ONCE(!in_task());
864 VM_WARN_ON_IRQS_ENABLED();
869 __this_cpu_add(memcg->vmstats_percpu->state[idx], val);
872 __this_cpu_add(pn->lruvec_stats_percpu->state[idx], val);
874 memcg_rstat_updated(memcg, memcg_state_val_in_pages(idx, val));
875 memcg_stats_unlock();
879 * __mod_lruvec_state - update lruvec memory statistics
880 * @lruvec: the lruvec
881 * @idx: the stat item
882 * @val: delta to add to the counter, can be negative
884 * The lruvec is the intersection of the NUMA node and a cgroup. This
885 * function updates the all three counters that are affected by a
886 * change of state at this level: per-node, per-cgroup, per-lruvec.
888 void __mod_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx,
892 __mod_node_page_state(lruvec_pgdat(lruvec), idx, val);
894 /* Update memcg and lruvec */
895 if (!mem_cgroup_disabled())
896 __mod_memcg_lruvec_state(lruvec, idx, val);
899 void __lruvec_stat_mod_folio(struct folio *folio, enum node_stat_item idx,
902 struct mem_cgroup *memcg;
903 pg_data_t *pgdat = folio_pgdat(folio);
904 struct lruvec *lruvec;
907 memcg = folio_memcg(folio);
908 /* Untracked pages have no memcg, no lruvec. Update only the node */
911 __mod_node_page_state(pgdat, idx, val);
915 lruvec = mem_cgroup_lruvec(memcg, pgdat);
916 __mod_lruvec_state(lruvec, idx, val);
919 EXPORT_SYMBOL(__lruvec_stat_mod_folio);
921 void __mod_lruvec_kmem_state(void *p, enum node_stat_item idx, int val)
923 pg_data_t *pgdat = page_pgdat(virt_to_page(p));
924 struct mem_cgroup *memcg;
925 struct lruvec *lruvec;
928 memcg = mem_cgroup_from_slab_obj(p);
931 * Untracked pages have no memcg, no lruvec. Update only the
932 * node. If we reparent the slab objects to the root memcg,
933 * when we free the slab object, we need to update the per-memcg
934 * vmstats to keep it correct for the root memcg.
937 __mod_node_page_state(pgdat, idx, val);
939 lruvec = mem_cgroup_lruvec(memcg, pgdat);
940 __mod_lruvec_state(lruvec, idx, val);
946 * __count_memcg_events - account VM events in a cgroup
947 * @memcg: the memory cgroup
948 * @idx: the event item
949 * @count: the number of events that occurred
951 void __count_memcg_events(struct mem_cgroup *memcg, enum vm_event_item idx,
954 int index = memcg_events_index(idx);
956 if (mem_cgroup_disabled() || index < 0)
960 __this_cpu_add(memcg->vmstats_percpu->events[index], count);
961 memcg_rstat_updated(memcg, count);
962 memcg_stats_unlock();
965 static unsigned long memcg_events(struct mem_cgroup *memcg, int event)
967 int index = memcg_events_index(event);
971 return READ_ONCE(memcg->vmstats->events[index]);
974 static unsigned long memcg_events_local(struct mem_cgroup *memcg, int event)
976 int index = memcg_events_index(event);
981 return READ_ONCE(memcg->vmstats->events_local[index]);
984 static void mem_cgroup_charge_statistics(struct mem_cgroup *memcg,
987 /* pagein of a big page is an event. So, ignore page size */
989 __count_memcg_events(memcg, PGPGIN, 1);
991 __count_memcg_events(memcg, PGPGOUT, 1);
992 nr_pages = -nr_pages; /* for event */
995 __this_cpu_add(memcg->vmstats_percpu->nr_page_events, nr_pages);
998 static bool mem_cgroup_event_ratelimit(struct mem_cgroup *memcg,
999 enum mem_cgroup_events_target target)
1001 unsigned long val, next;
1003 val = __this_cpu_read(memcg->vmstats_percpu->nr_page_events);
1004 next = __this_cpu_read(memcg->vmstats_percpu->targets[target]);
1005 /* from time_after() in jiffies.h */
1006 if ((long)(next - val) < 0) {
1008 case MEM_CGROUP_TARGET_THRESH:
1009 next = val + THRESHOLDS_EVENTS_TARGET;
1011 case MEM_CGROUP_TARGET_SOFTLIMIT:
1012 next = val + SOFTLIMIT_EVENTS_TARGET;
1017 __this_cpu_write(memcg->vmstats_percpu->targets[target], next);
1024 * Check events in order.
1027 static void memcg_check_events(struct mem_cgroup *memcg, int nid)
1029 if (IS_ENABLED(CONFIG_PREEMPT_RT))
1032 /* threshold event is triggered in finer grain than soft limit */
1033 if (unlikely(mem_cgroup_event_ratelimit(memcg,
1034 MEM_CGROUP_TARGET_THRESH))) {
1037 do_softlimit = mem_cgroup_event_ratelimit(memcg,
1038 MEM_CGROUP_TARGET_SOFTLIMIT);
1039 mem_cgroup_threshold(memcg);
1040 if (unlikely(do_softlimit))
1041 mem_cgroup_update_tree(memcg, nid);
1045 struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
1048 * mm_update_next_owner() may clear mm->owner to NULL
1049 * if it races with swapoff, page migration, etc.
1050 * So this can be called with p == NULL.
1055 return mem_cgroup_from_css(task_css(p, memory_cgrp_id));
1057 EXPORT_SYMBOL(mem_cgroup_from_task);
1059 static __always_inline struct mem_cgroup *active_memcg(void)
1062 return this_cpu_read(int_active_memcg);
1064 return current->active_memcg;
1068 * get_mem_cgroup_from_mm: Obtain a reference on given mm_struct's memcg.
1069 * @mm: mm from which memcg should be extracted. It can be NULL.
1071 * Obtain a reference on mm->memcg and returns it if successful. If mm
1072 * is NULL, then the memcg is chosen as follows:
1073 * 1) The active memcg, if set.
1074 * 2) current->mm->memcg, if available
1076 * If mem_cgroup is disabled, NULL is returned.
1078 struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm)
1080 struct mem_cgroup *memcg;
1082 if (mem_cgroup_disabled())
1086 * Page cache insertions can happen without an
1087 * actual mm context, e.g. during disk probing
1088 * on boot, loopback IO, acct() writes etc.
1090 * No need to css_get on root memcg as the reference
1091 * counting is disabled on the root level in the
1092 * cgroup core. See CSS_NO_REF.
1094 if (unlikely(!mm)) {
1095 memcg = active_memcg();
1096 if (unlikely(memcg)) {
1097 /* remote memcg must hold a ref */
1098 css_get(&memcg->css);
1103 return root_mem_cgroup;
1108 memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
1109 if (unlikely(!memcg))
1110 memcg = root_mem_cgroup;
1111 } while (!css_tryget(&memcg->css));
1115 EXPORT_SYMBOL(get_mem_cgroup_from_mm);
1118 * get_mem_cgroup_from_current - Obtain a reference on current task's memcg.
1120 struct mem_cgroup *get_mem_cgroup_from_current(void)
1122 struct mem_cgroup *memcg;
1124 if (mem_cgroup_disabled())
1129 memcg = mem_cgroup_from_task(current);
1130 if (!css_tryget(&memcg->css)) {
1139 * mem_cgroup_iter - iterate over memory cgroup hierarchy
1140 * @root: hierarchy root
1141 * @prev: previously returned memcg, NULL on first invocation
1142 * @reclaim: cookie for shared reclaim walks, NULL for full walks
1144 * Returns references to children of the hierarchy below @root, or
1145 * @root itself, or %NULL after a full round-trip.
1147 * Caller must pass the return value in @prev on subsequent
1148 * invocations for reference counting, or use mem_cgroup_iter_break()
1149 * to cancel a hierarchy walk before the round-trip is complete.
1151 * Reclaimers can specify a node in @reclaim to divide up the memcgs
1152 * in the hierarchy among all concurrent reclaimers operating on the
1155 struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root,
1156 struct mem_cgroup *prev,
1157 struct mem_cgroup_reclaim_cookie *reclaim)
1159 struct mem_cgroup_reclaim_iter *iter;
1160 struct cgroup_subsys_state *css = NULL;
1161 struct mem_cgroup *memcg = NULL;
1162 struct mem_cgroup *pos = NULL;
1164 if (mem_cgroup_disabled())
1168 root = root_mem_cgroup;
1173 struct mem_cgroup_per_node *mz;
1175 mz = root->nodeinfo[reclaim->pgdat->node_id];
1179 * On start, join the current reclaim iteration cycle.
1180 * Exit when a concurrent walker completes it.
1183 reclaim->generation = iter->generation;
1184 else if (reclaim->generation != iter->generation)
1188 pos = READ_ONCE(iter->position);
1189 if (!pos || css_tryget(&pos->css))
1192 * css reference reached zero, so iter->position will
1193 * be cleared by ->css_released. However, we should not
1194 * rely on this happening soon, because ->css_released
1195 * is called from a work queue, and by busy-waiting we
1196 * might block it. So we clear iter->position right
1199 (void)cmpxchg(&iter->position, pos, NULL);
1209 css = css_next_descendant_pre(css, &root->css);
1212 * Reclaimers share the hierarchy walk, and a
1213 * new one might jump in right at the end of
1214 * the hierarchy - make sure they see at least
1215 * one group and restart from the beginning.
1223 * Verify the css and acquire a reference. The root
1224 * is provided by the caller, so we know it's alive
1225 * and kicking, and don't take an extra reference.
1227 if (css == &root->css || css_tryget(css)) {
1228 memcg = mem_cgroup_from_css(css);
1235 * The position could have already been updated by a competing
1236 * thread, so check that the value hasn't changed since we read
1237 * it to avoid reclaiming from the same cgroup twice.
1239 (void)cmpxchg(&iter->position, pos, memcg);
1250 if (prev && prev != root)
1251 css_put(&prev->css);
1257 * mem_cgroup_iter_break - abort a hierarchy walk prematurely
1258 * @root: hierarchy root
1259 * @prev: last visited hierarchy member as returned by mem_cgroup_iter()
1261 void mem_cgroup_iter_break(struct mem_cgroup *root,
1262 struct mem_cgroup *prev)
1265 root = root_mem_cgroup;
1266 if (prev && prev != root)
1267 css_put(&prev->css);
1270 static void __invalidate_reclaim_iterators(struct mem_cgroup *from,
1271 struct mem_cgroup *dead_memcg)
1273 struct mem_cgroup_reclaim_iter *iter;
1274 struct mem_cgroup_per_node *mz;
1277 for_each_node(nid) {
1278 mz = from->nodeinfo[nid];
1280 cmpxchg(&iter->position, dead_memcg, NULL);
1284 static void invalidate_reclaim_iterators(struct mem_cgroup *dead_memcg)
1286 struct mem_cgroup *memcg = dead_memcg;
1287 struct mem_cgroup *last;
1290 __invalidate_reclaim_iterators(memcg, dead_memcg);
1292 } while ((memcg = parent_mem_cgroup(memcg)));
1295 * When cgroup1 non-hierarchy mode is used,
1296 * parent_mem_cgroup() does not walk all the way up to the
1297 * cgroup root (root_mem_cgroup). So we have to handle
1298 * dead_memcg from cgroup root separately.
1300 if (!mem_cgroup_is_root(last))
1301 __invalidate_reclaim_iterators(root_mem_cgroup,
1306 * mem_cgroup_scan_tasks - iterate over tasks of a memory cgroup hierarchy
1307 * @memcg: hierarchy root
1308 * @fn: function to call for each task
1309 * @arg: argument passed to @fn
1311 * This function iterates over tasks attached to @memcg or to any of its
1312 * descendants and calls @fn for each task. If @fn returns a non-zero
1313 * value, the function breaks the iteration loop. Otherwise, it will iterate
1314 * over all tasks and return 0.
1316 * This function must not be called for the root memory cgroup.
1318 void mem_cgroup_scan_tasks(struct mem_cgroup *memcg,
1319 int (*fn)(struct task_struct *, void *), void *arg)
1321 struct mem_cgroup *iter;
1324 BUG_ON(mem_cgroup_is_root(memcg));
1326 for_each_mem_cgroup_tree(iter, memcg) {
1327 struct css_task_iter it;
1328 struct task_struct *task;
1330 css_task_iter_start(&iter->css, CSS_TASK_ITER_PROCS, &it);
1331 while (!ret && (task = css_task_iter_next(&it)))
1332 ret = fn(task, arg);
1333 css_task_iter_end(&it);
1335 mem_cgroup_iter_break(memcg, iter);
1341 #ifdef CONFIG_DEBUG_VM
1342 void lruvec_memcg_debug(struct lruvec *lruvec, struct folio *folio)
1344 struct mem_cgroup *memcg;
1346 if (mem_cgroup_disabled())
1349 memcg = folio_memcg(folio);
1352 VM_BUG_ON_FOLIO(!mem_cgroup_is_root(lruvec_memcg(lruvec)), folio);
1354 VM_BUG_ON_FOLIO(lruvec_memcg(lruvec) != memcg, folio);
1359 * folio_lruvec_lock - Lock the lruvec for a folio.
1360 * @folio: Pointer to the folio.
1362 * These functions are safe to use under any of the following conditions:
1364 * - folio_test_lru false
1365 * - folio_memcg_lock()
1366 * - folio frozen (refcount of 0)
1368 * Return: The lruvec this folio is on with its lock held.
1370 struct lruvec *folio_lruvec_lock(struct folio *folio)
1372 struct lruvec *lruvec = folio_lruvec(folio);
1374 spin_lock(&lruvec->lru_lock);
1375 lruvec_memcg_debug(lruvec, folio);
1381 * folio_lruvec_lock_irq - Lock the lruvec for a folio.
1382 * @folio: Pointer to the folio.
1384 * These functions are safe to use under any of the following conditions:
1386 * - folio_test_lru false
1387 * - folio_memcg_lock()
1388 * - folio frozen (refcount of 0)
1390 * Return: The lruvec this folio is on with its lock held and interrupts
1393 struct lruvec *folio_lruvec_lock_irq(struct folio *folio)
1395 struct lruvec *lruvec = folio_lruvec(folio);
1397 spin_lock_irq(&lruvec->lru_lock);
1398 lruvec_memcg_debug(lruvec, folio);
1404 * folio_lruvec_lock_irqsave - Lock the lruvec for a folio.
1405 * @folio: Pointer to the folio.
1406 * @flags: Pointer to irqsave flags.
1408 * These functions are safe to use under any of the following conditions:
1410 * - folio_test_lru false
1411 * - folio_memcg_lock()
1412 * - folio frozen (refcount of 0)
1414 * Return: The lruvec this folio is on with its lock held and interrupts
1417 struct lruvec *folio_lruvec_lock_irqsave(struct folio *folio,
1418 unsigned long *flags)
1420 struct lruvec *lruvec = folio_lruvec(folio);
1422 spin_lock_irqsave(&lruvec->lru_lock, *flags);
1423 lruvec_memcg_debug(lruvec, folio);
1429 * mem_cgroup_update_lru_size - account for adding or removing an lru page
1430 * @lruvec: mem_cgroup per zone lru vector
1431 * @lru: index of lru list the page is sitting on
1432 * @zid: zone id of the accounted pages
1433 * @nr_pages: positive when adding or negative when removing
1435 * This function must be called under lru_lock, just before a page is added
1436 * to or just after a page is removed from an lru list.
1438 void mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru,
1439 int zid, int nr_pages)
1441 struct mem_cgroup_per_node *mz;
1442 unsigned long *lru_size;
1445 if (mem_cgroup_disabled())
1448 mz = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
1449 lru_size = &mz->lru_zone_size[zid][lru];
1452 *lru_size += nr_pages;
1455 if (WARN_ONCE(size < 0,
1456 "%s(%p, %d, %d): lru_size %ld\n",
1457 __func__, lruvec, lru, nr_pages, size)) {
1463 *lru_size += nr_pages;
1467 * mem_cgroup_margin - calculate chargeable space of a memory cgroup
1468 * @memcg: the memory cgroup
1470 * Returns the maximum amount of memory @mem can be charged with, in
1473 static unsigned long mem_cgroup_margin(struct mem_cgroup *memcg)
1475 unsigned long margin = 0;
1476 unsigned long count;
1477 unsigned long limit;
1479 count = page_counter_read(&memcg->memory);
1480 limit = READ_ONCE(memcg->memory.max);
1482 margin = limit - count;
1484 if (do_memsw_account()) {
1485 count = page_counter_read(&memcg->memsw);
1486 limit = READ_ONCE(memcg->memsw.max);
1488 margin = min(margin, limit - count);
1497 * A routine for checking "mem" is under move_account() or not.
1499 * Checking a cgroup is mc.from or mc.to or under hierarchy of
1500 * moving cgroups. This is for waiting at high-memory pressure
1503 static bool mem_cgroup_under_move(struct mem_cgroup *memcg)
1505 struct mem_cgroup *from;
1506 struct mem_cgroup *to;
1509 * Unlike task_move routines, we access mc.to, mc.from not under
1510 * mutual exclusion by cgroup_mutex. Here, we take spinlock instead.
1512 spin_lock(&mc.lock);
1518 ret = mem_cgroup_is_descendant(from, memcg) ||
1519 mem_cgroup_is_descendant(to, memcg);
1521 spin_unlock(&mc.lock);
1525 static bool mem_cgroup_wait_acct_move(struct mem_cgroup *memcg)
1527 if (mc.moving_task && current != mc.moving_task) {
1528 if (mem_cgroup_under_move(memcg)) {
1530 prepare_to_wait(&mc.waitq, &wait, TASK_INTERRUPTIBLE);
1531 /* moving charge context might have finished. */
1534 finish_wait(&mc.waitq, &wait);
1541 struct memory_stat {
1546 static const struct memory_stat memory_stats[] = {
1547 { "anon", NR_ANON_MAPPED },
1548 { "file", NR_FILE_PAGES },
1549 { "kernel", MEMCG_KMEM },
1550 { "kernel_stack", NR_KERNEL_STACK_KB },
1551 { "pagetables", NR_PAGETABLE },
1552 { "sec_pagetables", NR_SECONDARY_PAGETABLE },
1553 { "percpu", MEMCG_PERCPU_B },
1554 { "sock", MEMCG_SOCK },
1555 { "vmalloc", MEMCG_VMALLOC },
1556 { "shmem", NR_SHMEM },
1557 #if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_ZSWAP)
1558 { "zswap", MEMCG_ZSWAP_B },
1559 { "zswapped", MEMCG_ZSWAPPED },
1561 { "file_mapped", NR_FILE_MAPPED },
1562 { "file_dirty", NR_FILE_DIRTY },
1563 { "file_writeback", NR_WRITEBACK },
1565 { "swapcached", NR_SWAPCACHE },
1567 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
1568 { "anon_thp", NR_ANON_THPS },
1569 { "file_thp", NR_FILE_THPS },
1570 { "shmem_thp", NR_SHMEM_THPS },
1572 { "inactive_anon", NR_INACTIVE_ANON },
1573 { "active_anon", NR_ACTIVE_ANON },
1574 { "inactive_file", NR_INACTIVE_FILE },
1575 { "active_file", NR_ACTIVE_FILE },
1576 { "unevictable", NR_UNEVICTABLE },
1577 { "slab_reclaimable", NR_SLAB_RECLAIMABLE_B },
1578 { "slab_unreclaimable", NR_SLAB_UNRECLAIMABLE_B },
1580 /* The memory events */
1581 { "workingset_refault_anon", WORKINGSET_REFAULT_ANON },
1582 { "workingset_refault_file", WORKINGSET_REFAULT_FILE },
1583 { "workingset_activate_anon", WORKINGSET_ACTIVATE_ANON },
1584 { "workingset_activate_file", WORKINGSET_ACTIVATE_FILE },
1585 { "workingset_restore_anon", WORKINGSET_RESTORE_ANON },
1586 { "workingset_restore_file", WORKINGSET_RESTORE_FILE },
1587 { "workingset_nodereclaim", WORKINGSET_NODERECLAIM },
1590 /* The actual unit of the state item, not the same as the output unit */
1591 static int memcg_page_state_unit(int item)
1594 case MEMCG_PERCPU_B:
1596 case NR_SLAB_RECLAIMABLE_B:
1597 case NR_SLAB_UNRECLAIMABLE_B:
1599 case NR_KERNEL_STACK_KB:
1606 /* Translate stat items to the correct unit for memory.stat output */
1607 static int memcg_page_state_output_unit(int item)
1610 * Workingset state is actually in pages, but we export it to userspace
1611 * as a scalar count of events, so special case it here.
1614 case WORKINGSET_REFAULT_ANON:
1615 case WORKINGSET_REFAULT_FILE:
1616 case WORKINGSET_ACTIVATE_ANON:
1617 case WORKINGSET_ACTIVATE_FILE:
1618 case WORKINGSET_RESTORE_ANON:
1619 case WORKINGSET_RESTORE_FILE:
1620 case WORKINGSET_NODERECLAIM:
1623 return memcg_page_state_unit(item);
1627 static inline unsigned long memcg_page_state_output(struct mem_cgroup *memcg,
1630 return memcg_page_state(memcg, item) *
1631 memcg_page_state_output_unit(item);
1634 static inline unsigned long memcg_page_state_local_output(
1635 struct mem_cgroup *memcg, int item)
1637 return memcg_page_state_local(memcg, item) *
1638 memcg_page_state_output_unit(item);
1641 static void memcg_stat_format(struct mem_cgroup *memcg, struct seq_buf *s)
1646 * Provide statistics on the state of the memory subsystem as
1647 * well as cumulative event counters that show past behavior.
1649 * This list is ordered following a combination of these gradients:
1650 * 1) generic big picture -> specifics and details
1651 * 2) reflecting userspace activity -> reflecting kernel heuristics
1653 * Current memory state:
1655 mem_cgroup_flush_stats(memcg);
1657 for (i = 0; i < ARRAY_SIZE(memory_stats); i++) {
1660 size = memcg_page_state_output(memcg, memory_stats[i].idx);
1661 seq_buf_printf(s, "%s %llu\n", memory_stats[i].name, size);
1663 if (unlikely(memory_stats[i].idx == NR_SLAB_UNRECLAIMABLE_B)) {
1664 size += memcg_page_state_output(memcg,
1665 NR_SLAB_RECLAIMABLE_B);
1666 seq_buf_printf(s, "slab %llu\n", size);
1670 /* Accumulated memory events */
1671 seq_buf_printf(s, "pgscan %lu\n",
1672 memcg_events(memcg, PGSCAN_KSWAPD) +
1673 memcg_events(memcg, PGSCAN_DIRECT) +
1674 memcg_events(memcg, PGSCAN_KHUGEPAGED));
1675 seq_buf_printf(s, "pgsteal %lu\n",
1676 memcg_events(memcg, PGSTEAL_KSWAPD) +
1677 memcg_events(memcg, PGSTEAL_DIRECT) +
1678 memcg_events(memcg, PGSTEAL_KHUGEPAGED));
1680 for (i = 0; i < ARRAY_SIZE(memcg_vm_event_stat); i++) {
1681 if (memcg_vm_event_stat[i] == PGPGIN ||
1682 memcg_vm_event_stat[i] == PGPGOUT)
1685 seq_buf_printf(s, "%s %lu\n",
1686 vm_event_name(memcg_vm_event_stat[i]),
1687 memcg_events(memcg, memcg_vm_event_stat[i]));
1690 /* The above should easily fit into one page */
1691 WARN_ON_ONCE(seq_buf_has_overflowed(s));
1694 static void memcg1_stat_format(struct mem_cgroup *memcg, struct seq_buf *s);
1696 static void memory_stat_format(struct mem_cgroup *memcg, struct seq_buf *s)
1698 if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
1699 memcg_stat_format(memcg, s);
1701 memcg1_stat_format(memcg, s);
1702 WARN_ON_ONCE(seq_buf_has_overflowed(s));
1706 * mem_cgroup_print_oom_context: Print OOM information relevant to
1707 * memory controller.
1708 * @memcg: The memory cgroup that went over limit
1709 * @p: Task that is going to be killed
1711 * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is
1714 void mem_cgroup_print_oom_context(struct mem_cgroup *memcg, struct task_struct *p)
1719 pr_cont(",oom_memcg=");
1720 pr_cont_cgroup_path(memcg->css.cgroup);
1722 pr_cont(",global_oom");
1724 pr_cont(",task_memcg=");
1725 pr_cont_cgroup_path(task_cgroup(p, memory_cgrp_id));
1731 * mem_cgroup_print_oom_meminfo: Print OOM memory information relevant to
1732 * memory controller.
1733 * @memcg: The memory cgroup that went over limit
1735 void mem_cgroup_print_oom_meminfo(struct mem_cgroup *memcg)
1737 /* Use static buffer, for the caller is holding oom_lock. */
1738 static char buf[PAGE_SIZE];
1741 lockdep_assert_held(&oom_lock);
1743 pr_info("memory: usage %llukB, limit %llukB, failcnt %lu\n",
1744 K((u64)page_counter_read(&memcg->memory)),
1745 K((u64)READ_ONCE(memcg->memory.max)), memcg->memory.failcnt);
1746 if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
1747 pr_info("swap: usage %llukB, limit %llukB, failcnt %lu\n",
1748 K((u64)page_counter_read(&memcg->swap)),
1749 K((u64)READ_ONCE(memcg->swap.max)), memcg->swap.failcnt);
1751 pr_info("memory+swap: usage %llukB, limit %llukB, failcnt %lu\n",
1752 K((u64)page_counter_read(&memcg->memsw)),
1753 K((u64)memcg->memsw.max), memcg->memsw.failcnt);
1754 pr_info("kmem: usage %llukB, limit %llukB, failcnt %lu\n",
1755 K((u64)page_counter_read(&memcg->kmem)),
1756 K((u64)memcg->kmem.max), memcg->kmem.failcnt);
1759 pr_info("Memory cgroup stats for ");
1760 pr_cont_cgroup_path(memcg->css.cgroup);
1762 seq_buf_init(&s, buf, sizeof(buf));
1763 memory_stat_format(memcg, &s);
1764 seq_buf_do_printk(&s, KERN_INFO);
1768 * Return the memory (and swap, if configured) limit for a memcg.
1770 unsigned long mem_cgroup_get_max(struct mem_cgroup *memcg)
1772 unsigned long max = READ_ONCE(memcg->memory.max);
1774 if (do_memsw_account()) {
1775 if (mem_cgroup_swappiness(memcg)) {
1776 /* Calculate swap excess capacity from memsw limit */
1777 unsigned long swap = READ_ONCE(memcg->memsw.max) - max;
1779 max += min(swap, (unsigned long)total_swap_pages);
1782 if (mem_cgroup_swappiness(memcg))
1783 max += min(READ_ONCE(memcg->swap.max),
1784 (unsigned long)total_swap_pages);
1789 unsigned long mem_cgroup_size(struct mem_cgroup *memcg)
1791 return page_counter_read(&memcg->memory);
1794 static bool mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask,
1797 struct oom_control oc = {
1801 .gfp_mask = gfp_mask,
1806 if (mutex_lock_killable(&oom_lock))
1809 if (mem_cgroup_margin(memcg) >= (1 << order))
1813 * A few threads which were not waiting at mutex_lock_killable() can
1814 * fail to bail out. Therefore, check again after holding oom_lock.
1816 ret = task_is_dying() || out_of_memory(&oc);
1819 mutex_unlock(&oom_lock);
1823 static int mem_cgroup_soft_reclaim(struct mem_cgroup *root_memcg,
1826 unsigned long *total_scanned)
1828 struct mem_cgroup *victim = NULL;
1831 unsigned long excess;
1832 unsigned long nr_scanned;
1833 struct mem_cgroup_reclaim_cookie reclaim = {
1837 excess = soft_limit_excess(root_memcg);
1840 victim = mem_cgroup_iter(root_memcg, victim, &reclaim);
1845 * If we have not been able to reclaim
1846 * anything, it might because there are
1847 * no reclaimable pages under this hierarchy
1852 * We want to do more targeted reclaim.
1853 * excess >> 2 is not to excessive so as to
1854 * reclaim too much, nor too less that we keep
1855 * coming back to reclaim from this cgroup
1857 if (total >= (excess >> 2) ||
1858 (loop > MEM_CGROUP_MAX_RECLAIM_LOOPS))
1863 total += mem_cgroup_shrink_node(victim, gfp_mask, false,
1864 pgdat, &nr_scanned);
1865 *total_scanned += nr_scanned;
1866 if (!soft_limit_excess(root_memcg))
1869 mem_cgroup_iter_break(root_memcg, victim);
1873 #ifdef CONFIG_LOCKDEP
1874 static struct lockdep_map memcg_oom_lock_dep_map = {
1875 .name = "memcg_oom_lock",
1879 static DEFINE_SPINLOCK(memcg_oom_lock);
1882 * Check OOM-Killer is already running under our hierarchy.
1883 * If someone is running, return false.
1885 static bool mem_cgroup_oom_trylock(struct mem_cgroup *memcg)
1887 struct mem_cgroup *iter, *failed = NULL;
1889 spin_lock(&memcg_oom_lock);
1891 for_each_mem_cgroup_tree(iter, memcg) {
1892 if (iter->oom_lock) {
1894 * this subtree of our hierarchy is already locked
1895 * so we cannot give a lock.
1898 mem_cgroup_iter_break(memcg, iter);
1901 iter->oom_lock = true;
1906 * OK, we failed to lock the whole subtree so we have
1907 * to clean up what we set up to the failing subtree
1909 for_each_mem_cgroup_tree(iter, memcg) {
1910 if (iter == failed) {
1911 mem_cgroup_iter_break(memcg, iter);
1914 iter->oom_lock = false;
1917 mutex_acquire(&memcg_oom_lock_dep_map, 0, 1, _RET_IP_);
1919 spin_unlock(&memcg_oom_lock);
1924 static void mem_cgroup_oom_unlock(struct mem_cgroup *memcg)
1926 struct mem_cgroup *iter;
1928 spin_lock(&memcg_oom_lock);
1929 mutex_release(&memcg_oom_lock_dep_map, _RET_IP_);
1930 for_each_mem_cgroup_tree(iter, memcg)
1931 iter->oom_lock = false;
1932 spin_unlock(&memcg_oom_lock);
1935 static void mem_cgroup_mark_under_oom(struct mem_cgroup *memcg)
1937 struct mem_cgroup *iter;
1939 spin_lock(&memcg_oom_lock);
1940 for_each_mem_cgroup_tree(iter, memcg)
1942 spin_unlock(&memcg_oom_lock);
1945 static void mem_cgroup_unmark_under_oom(struct mem_cgroup *memcg)
1947 struct mem_cgroup *iter;
1950 * Be careful about under_oom underflows because a child memcg
1951 * could have been added after mem_cgroup_mark_under_oom.
1953 spin_lock(&memcg_oom_lock);
1954 for_each_mem_cgroup_tree(iter, memcg)
1955 if (iter->under_oom > 0)
1957 spin_unlock(&memcg_oom_lock);
1960 static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq);
1962 struct oom_wait_info {
1963 struct mem_cgroup *memcg;
1964 wait_queue_entry_t wait;
1967 static int memcg_oom_wake_function(wait_queue_entry_t *wait,
1968 unsigned mode, int sync, void *arg)
1970 struct mem_cgroup *wake_memcg = (struct mem_cgroup *)arg;
1971 struct mem_cgroup *oom_wait_memcg;
1972 struct oom_wait_info *oom_wait_info;
1974 oom_wait_info = container_of(wait, struct oom_wait_info, wait);
1975 oom_wait_memcg = oom_wait_info->memcg;
1977 if (!mem_cgroup_is_descendant(wake_memcg, oom_wait_memcg) &&
1978 !mem_cgroup_is_descendant(oom_wait_memcg, wake_memcg))
1980 return autoremove_wake_function(wait, mode, sync, arg);
1983 static void memcg_oom_recover(struct mem_cgroup *memcg)
1986 * For the following lockless ->under_oom test, the only required
1987 * guarantee is that it must see the state asserted by an OOM when
1988 * this function is called as a result of userland actions
1989 * triggered by the notification of the OOM. This is trivially
1990 * achieved by invoking mem_cgroup_mark_under_oom() before
1991 * triggering notification.
1993 if (memcg && memcg->under_oom)
1994 __wake_up(&memcg_oom_waitq, TASK_NORMAL, 0, memcg);
1998 * Returns true if successfully killed one or more processes. Though in some
1999 * corner cases it can return true even without killing any process.
2001 static bool mem_cgroup_oom(struct mem_cgroup *memcg, gfp_t mask, int order)
2005 if (order > PAGE_ALLOC_COSTLY_ORDER)
2008 memcg_memory_event(memcg, MEMCG_OOM);
2011 * We are in the middle of the charge context here, so we
2012 * don't want to block when potentially sitting on a callstack
2013 * that holds all kinds of filesystem and mm locks.
2015 * cgroup1 allows disabling the OOM killer and waiting for outside
2016 * handling until the charge can succeed; remember the context and put
2017 * the task to sleep at the end of the page fault when all locks are
2020 * On the other hand, in-kernel OOM killer allows for an async victim
2021 * memory reclaim (oom_reaper) and that means that we are not solely
2022 * relying on the oom victim to make a forward progress and we can
2023 * invoke the oom killer here.
2025 * Please note that mem_cgroup_out_of_memory might fail to find a
2026 * victim and then we have to bail out from the charge path.
2028 if (READ_ONCE(memcg->oom_kill_disable)) {
2029 if (current->in_user_fault) {
2030 css_get(&memcg->css);
2031 current->memcg_in_oom = memcg;
2032 current->memcg_oom_gfp_mask = mask;
2033 current->memcg_oom_order = order;
2038 mem_cgroup_mark_under_oom(memcg);
2040 locked = mem_cgroup_oom_trylock(memcg);
2043 mem_cgroup_oom_notify(memcg);
2045 mem_cgroup_unmark_under_oom(memcg);
2046 ret = mem_cgroup_out_of_memory(memcg, mask, order);
2049 mem_cgroup_oom_unlock(memcg);
2055 * mem_cgroup_oom_synchronize - complete memcg OOM handling
2056 * @handle: actually kill/wait or just clean up the OOM state
2058 * This has to be called at the end of a page fault if the memcg OOM
2059 * handler was enabled.
2061 * Memcg supports userspace OOM handling where failed allocations must
2062 * sleep on a waitqueue until the userspace task resolves the
2063 * situation. Sleeping directly in the charge context with all kinds
2064 * of locks held is not a good idea, instead we remember an OOM state
2065 * in the task and mem_cgroup_oom_synchronize() has to be called at
2066 * the end of the page fault to complete the OOM handling.
2068 * Returns %true if an ongoing memcg OOM situation was detected and
2069 * completed, %false otherwise.
2071 bool mem_cgroup_oom_synchronize(bool handle)
2073 struct mem_cgroup *memcg = current->memcg_in_oom;
2074 struct oom_wait_info owait;
2077 /* OOM is global, do not handle */
2084 owait.memcg = memcg;
2085 owait.wait.flags = 0;
2086 owait.wait.func = memcg_oom_wake_function;
2087 owait.wait.private = current;
2088 INIT_LIST_HEAD(&owait.wait.entry);
2090 prepare_to_wait(&memcg_oom_waitq, &owait.wait, TASK_KILLABLE);
2091 mem_cgroup_mark_under_oom(memcg);
2093 locked = mem_cgroup_oom_trylock(memcg);
2096 mem_cgroup_oom_notify(memcg);
2099 mem_cgroup_unmark_under_oom(memcg);
2100 finish_wait(&memcg_oom_waitq, &owait.wait);
2103 mem_cgroup_oom_unlock(memcg);
2105 current->memcg_in_oom = NULL;
2106 css_put(&memcg->css);
2111 * mem_cgroup_get_oom_group - get a memory cgroup to clean up after OOM
2112 * @victim: task to be killed by the OOM killer
2113 * @oom_domain: memcg in case of memcg OOM, NULL in case of system-wide OOM
2115 * Returns a pointer to a memory cgroup, which has to be cleaned up
2116 * by killing all belonging OOM-killable tasks.
2118 * Caller has to call mem_cgroup_put() on the returned non-NULL memcg.
2120 struct mem_cgroup *mem_cgroup_get_oom_group(struct task_struct *victim,
2121 struct mem_cgroup *oom_domain)
2123 struct mem_cgroup *oom_group = NULL;
2124 struct mem_cgroup *memcg;
2126 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys))
2130 oom_domain = root_mem_cgroup;
2134 memcg = mem_cgroup_from_task(victim);
2135 if (mem_cgroup_is_root(memcg))
2139 * If the victim task has been asynchronously moved to a different
2140 * memory cgroup, we might end up killing tasks outside oom_domain.
2141 * In this case it's better to ignore memory.group.oom.
2143 if (unlikely(!mem_cgroup_is_descendant(memcg, oom_domain)))
2147 * Traverse the memory cgroup hierarchy from the victim task's
2148 * cgroup up to the OOMing cgroup (or root) to find the
2149 * highest-level memory cgroup with oom.group set.
2151 for (; memcg; memcg = parent_mem_cgroup(memcg)) {
2152 if (READ_ONCE(memcg->oom_group))
2155 if (memcg == oom_domain)
2160 css_get(&oom_group->css);
2167 void mem_cgroup_print_oom_group(struct mem_cgroup *memcg)
2169 pr_info("Tasks in ");
2170 pr_cont_cgroup_path(memcg->css.cgroup);
2171 pr_cont(" are going to be killed due to memory.oom.group set\n");
2175 * folio_memcg_lock - Bind a folio to its memcg.
2176 * @folio: The folio.
2178 * This function prevents unlocked LRU folios from being moved to
2181 * It ensures lifetime of the bound memcg. The caller is responsible
2182 * for the lifetime of the folio.
2184 void folio_memcg_lock(struct folio *folio)
2186 struct mem_cgroup *memcg;
2187 unsigned long flags;
2190 * The RCU lock is held throughout the transaction. The fast
2191 * path can get away without acquiring the memcg->move_lock
2192 * because page moving starts with an RCU grace period.
2196 if (mem_cgroup_disabled())
2199 memcg = folio_memcg(folio);
2200 if (unlikely(!memcg))
2203 #ifdef CONFIG_PROVE_LOCKING
2204 local_irq_save(flags);
2205 might_lock(&memcg->move_lock);
2206 local_irq_restore(flags);
2209 if (atomic_read(&memcg->moving_account) <= 0)
2212 spin_lock_irqsave(&memcg->move_lock, flags);
2213 if (memcg != folio_memcg(folio)) {
2214 spin_unlock_irqrestore(&memcg->move_lock, flags);
2219 * When charge migration first begins, we can have multiple
2220 * critical sections holding the fast-path RCU lock and one
2221 * holding the slowpath move_lock. Track the task who has the
2222 * move_lock for folio_memcg_unlock().
2224 memcg->move_lock_task = current;
2225 memcg->move_lock_flags = flags;
2228 static void __folio_memcg_unlock(struct mem_cgroup *memcg)
2230 if (memcg && memcg->move_lock_task == current) {
2231 unsigned long flags = memcg->move_lock_flags;
2233 memcg->move_lock_task = NULL;
2234 memcg->move_lock_flags = 0;
2236 spin_unlock_irqrestore(&memcg->move_lock, flags);
2243 * folio_memcg_unlock - Release the binding between a folio and its memcg.
2244 * @folio: The folio.
2246 * This releases the binding created by folio_memcg_lock(). This does
2247 * not change the accounting of this folio to its memcg, but it does
2248 * permit others to change it.
2250 void folio_memcg_unlock(struct folio *folio)
2252 __folio_memcg_unlock(folio_memcg(folio));
2255 struct memcg_stock_pcp {
2256 local_lock_t stock_lock;
2257 struct mem_cgroup *cached; /* this never be root cgroup */
2258 unsigned int nr_pages;
2260 #ifdef CONFIG_MEMCG_KMEM
2261 struct obj_cgroup *cached_objcg;
2262 struct pglist_data *cached_pgdat;
2263 unsigned int nr_bytes;
2264 int nr_slab_reclaimable_b;
2265 int nr_slab_unreclaimable_b;
2268 struct work_struct work;
2269 unsigned long flags;
2270 #define FLUSHING_CACHED_CHARGE 0
2272 static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock) = {
2273 .stock_lock = INIT_LOCAL_LOCK(stock_lock),
2275 static DEFINE_MUTEX(percpu_charge_mutex);
2277 #ifdef CONFIG_MEMCG_KMEM
2278 static struct obj_cgroup *drain_obj_stock(struct memcg_stock_pcp *stock);
2279 static bool obj_stock_flush_required(struct memcg_stock_pcp *stock,
2280 struct mem_cgroup *root_memcg);
2281 static void memcg_account_kmem(struct mem_cgroup *memcg, int nr_pages);
2284 static inline struct obj_cgroup *drain_obj_stock(struct memcg_stock_pcp *stock)
2288 static bool obj_stock_flush_required(struct memcg_stock_pcp *stock,
2289 struct mem_cgroup *root_memcg)
2293 static void memcg_account_kmem(struct mem_cgroup *memcg, int nr_pages)
2299 * consume_stock: Try to consume stocked charge on this cpu.
2300 * @memcg: memcg to consume from.
2301 * @nr_pages: how many pages to charge.
2303 * The charges will only happen if @memcg matches the current cpu's memcg
2304 * stock, and at least @nr_pages are available in that stock. Failure to
2305 * service an allocation will refill the stock.
2307 * returns true if successful, false otherwise.
2309 static bool consume_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
2311 struct memcg_stock_pcp *stock;
2312 unsigned long flags;
2315 if (nr_pages > MEMCG_CHARGE_BATCH)
2318 local_lock_irqsave(&memcg_stock.stock_lock, flags);
2320 stock = this_cpu_ptr(&memcg_stock);
2321 if (memcg == READ_ONCE(stock->cached) && stock->nr_pages >= nr_pages) {
2322 stock->nr_pages -= nr_pages;
2326 local_unlock_irqrestore(&memcg_stock.stock_lock, flags);
2332 * Returns stocks cached in percpu and reset cached information.
2334 static void drain_stock(struct memcg_stock_pcp *stock)
2336 struct mem_cgroup *old = READ_ONCE(stock->cached);
2341 if (stock->nr_pages) {
2342 page_counter_uncharge(&old->memory, stock->nr_pages);
2343 if (do_memsw_account())
2344 page_counter_uncharge(&old->memsw, stock->nr_pages);
2345 stock->nr_pages = 0;
2349 WRITE_ONCE(stock->cached, NULL);
2352 static void drain_local_stock(struct work_struct *dummy)
2354 struct memcg_stock_pcp *stock;
2355 struct obj_cgroup *old = NULL;
2356 unsigned long flags;
2359 * The only protection from cpu hotplug (memcg_hotplug_cpu_dead) vs.
2360 * drain_stock races is that we always operate on local CPU stock
2361 * here with IRQ disabled
2363 local_lock_irqsave(&memcg_stock.stock_lock, flags);
2365 stock = this_cpu_ptr(&memcg_stock);
2366 old = drain_obj_stock(stock);
2368 clear_bit(FLUSHING_CACHED_CHARGE, &stock->flags);
2370 local_unlock_irqrestore(&memcg_stock.stock_lock, flags);
2372 obj_cgroup_put(old);
2376 * Cache charges(val) to local per_cpu area.
2377 * This will be consumed by consume_stock() function, later.
2379 static void __refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
2381 struct memcg_stock_pcp *stock;
2383 stock = this_cpu_ptr(&memcg_stock);
2384 if (READ_ONCE(stock->cached) != memcg) { /* reset if necessary */
2386 css_get(&memcg->css);
2387 WRITE_ONCE(stock->cached, memcg);
2389 stock->nr_pages += nr_pages;
2391 if (stock->nr_pages > MEMCG_CHARGE_BATCH)
2395 static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
2397 unsigned long flags;
2399 local_lock_irqsave(&memcg_stock.stock_lock, flags);
2400 __refill_stock(memcg, nr_pages);
2401 local_unlock_irqrestore(&memcg_stock.stock_lock, flags);
2405 * Drains all per-CPU charge caches for given root_memcg resp. subtree
2406 * of the hierarchy under it.
2408 static void drain_all_stock(struct mem_cgroup *root_memcg)
2412 /* If someone's already draining, avoid adding running more workers. */
2413 if (!mutex_trylock(&percpu_charge_mutex))
2416 * Notify other cpus that system-wide "drain" is running
2417 * We do not care about races with the cpu hotplug because cpu down
2418 * as well as workers from this path always operate on the local
2419 * per-cpu data. CPU up doesn't touch memcg_stock at all.
2422 curcpu = smp_processor_id();
2423 for_each_online_cpu(cpu) {
2424 struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
2425 struct mem_cgroup *memcg;
2429 memcg = READ_ONCE(stock->cached);
2430 if (memcg && stock->nr_pages &&
2431 mem_cgroup_is_descendant(memcg, root_memcg))
2433 else if (obj_stock_flush_required(stock, root_memcg))
2438 !test_and_set_bit(FLUSHING_CACHED_CHARGE, &stock->flags)) {
2440 drain_local_stock(&stock->work);
2441 else if (!cpu_is_isolated(cpu))
2442 schedule_work_on(cpu, &stock->work);
2446 mutex_unlock(&percpu_charge_mutex);
2449 static int memcg_hotplug_cpu_dead(unsigned int cpu)
2451 struct memcg_stock_pcp *stock;
2453 stock = &per_cpu(memcg_stock, cpu);
2459 static unsigned long reclaim_high(struct mem_cgroup *memcg,
2460 unsigned int nr_pages,
2463 unsigned long nr_reclaimed = 0;
2466 unsigned long pflags;
2468 if (page_counter_read(&memcg->memory) <=
2469 READ_ONCE(memcg->memory.high))
2472 memcg_memory_event(memcg, MEMCG_HIGH);
2474 psi_memstall_enter(&pflags);
2475 nr_reclaimed += try_to_free_mem_cgroup_pages(memcg, nr_pages,
2477 MEMCG_RECLAIM_MAY_SWAP);
2478 psi_memstall_leave(&pflags);
2479 } while ((memcg = parent_mem_cgroup(memcg)) &&
2480 !mem_cgroup_is_root(memcg));
2482 return nr_reclaimed;
2485 static void high_work_func(struct work_struct *work)
2487 struct mem_cgroup *memcg;
2489 memcg = container_of(work, struct mem_cgroup, high_work);
2490 reclaim_high(memcg, MEMCG_CHARGE_BATCH, GFP_KERNEL);
2494 * Clamp the maximum sleep time per allocation batch to 2 seconds. This is
2495 * enough to still cause a significant slowdown in most cases, while still
2496 * allowing diagnostics and tracing to proceed without becoming stuck.
2498 #define MEMCG_MAX_HIGH_DELAY_JIFFIES (2UL*HZ)
2501 * When calculating the delay, we use these either side of the exponentiation to
2502 * maintain precision and scale to a reasonable number of jiffies (see the table
2505 * - MEMCG_DELAY_PRECISION_SHIFT: Extra precision bits while translating the
2506 * overage ratio to a delay.
2507 * - MEMCG_DELAY_SCALING_SHIFT: The number of bits to scale down the
2508 * proposed penalty in order to reduce to a reasonable number of jiffies, and
2509 * to produce a reasonable delay curve.
2511 * MEMCG_DELAY_SCALING_SHIFT just happens to be a number that produces a
2512 * reasonable delay curve compared to precision-adjusted overage, not
2513 * penalising heavily at first, but still making sure that growth beyond the
2514 * limit penalises misbehaviour cgroups by slowing them down exponentially. For
2515 * example, with a high of 100 megabytes:
2517 * +-------+------------------------+
2518 * | usage | time to allocate in ms |
2519 * +-------+------------------------+
2541 * +-------+------------------------+
2543 #define MEMCG_DELAY_PRECISION_SHIFT 20
2544 #define MEMCG_DELAY_SCALING_SHIFT 14
2546 static u64 calculate_overage(unsigned long usage, unsigned long high)
2554 * Prevent division by 0 in overage calculation by acting as if
2555 * it was a threshold of 1 page
2557 high = max(high, 1UL);
2559 overage = usage - high;
2560 overage <<= MEMCG_DELAY_PRECISION_SHIFT;
2561 return div64_u64(overage, high);
2564 static u64 mem_find_max_overage(struct mem_cgroup *memcg)
2566 u64 overage, max_overage = 0;
2569 overage = calculate_overage(page_counter_read(&memcg->memory),
2570 READ_ONCE(memcg->memory.high));
2571 max_overage = max(overage, max_overage);
2572 } while ((memcg = parent_mem_cgroup(memcg)) &&
2573 !mem_cgroup_is_root(memcg));
2578 static u64 swap_find_max_overage(struct mem_cgroup *memcg)
2580 u64 overage, max_overage = 0;
2583 overage = calculate_overage(page_counter_read(&memcg->swap),
2584 READ_ONCE(memcg->swap.high));
2586 memcg_memory_event(memcg, MEMCG_SWAP_HIGH);
2587 max_overage = max(overage, max_overage);
2588 } while ((memcg = parent_mem_cgroup(memcg)) &&
2589 !mem_cgroup_is_root(memcg));
2595 * Get the number of jiffies that we should penalise a mischievous cgroup which
2596 * is exceeding its memory.high by checking both it and its ancestors.
2598 static unsigned long calculate_high_delay(struct mem_cgroup *memcg,
2599 unsigned int nr_pages,
2602 unsigned long penalty_jiffies;
2608 * We use overage compared to memory.high to calculate the number of
2609 * jiffies to sleep (penalty_jiffies). Ideally this value should be
2610 * fairly lenient on small overages, and increasingly harsh when the
2611 * memcg in question makes it clear that it has no intention of stopping
2612 * its crazy behaviour, so we exponentially increase the delay based on
2615 penalty_jiffies = max_overage * max_overage * HZ;
2616 penalty_jiffies >>= MEMCG_DELAY_PRECISION_SHIFT;
2617 penalty_jiffies >>= MEMCG_DELAY_SCALING_SHIFT;
2620 * Factor in the task's own contribution to the overage, such that four
2621 * N-sized allocations are throttled approximately the same as one
2622 * 4N-sized allocation.
2624 * MEMCG_CHARGE_BATCH pages is nominal, so work out how much smaller or
2625 * larger the current charge patch is than that.
2627 return penalty_jiffies * nr_pages / MEMCG_CHARGE_BATCH;
2631 * Reclaims memory over the high limit. Called directly from
2632 * try_charge() (context permitting), as well as from the userland
2633 * return path where reclaim is always able to block.
2635 void mem_cgroup_handle_over_high(gfp_t gfp_mask)
2637 unsigned long penalty_jiffies;
2638 unsigned long pflags;
2639 unsigned long nr_reclaimed;
2640 unsigned int nr_pages = current->memcg_nr_pages_over_high;
2641 int nr_retries = MAX_RECLAIM_RETRIES;
2642 struct mem_cgroup *memcg;
2643 bool in_retry = false;
2645 if (likely(!nr_pages))
2648 memcg = get_mem_cgroup_from_mm(current->mm);
2649 current->memcg_nr_pages_over_high = 0;
2653 * Bail if the task is already exiting. Unlike memory.max,
2654 * memory.high enforcement isn't as strict, and there is no
2655 * OOM killer involved, which means the excess could already
2656 * be much bigger (and still growing) than it could for
2657 * memory.max; the dying task could get stuck in fruitless
2658 * reclaim for a long time, which isn't desirable.
2660 if (task_is_dying())
2664 * The allocating task should reclaim at least the batch size, but for
2665 * subsequent retries we only want to do what's necessary to prevent oom
2666 * or breaching resource isolation.
2668 * This is distinct from memory.max or page allocator behaviour because
2669 * memory.high is currently batched, whereas memory.max and the page
2670 * allocator run every time an allocation is made.
2672 nr_reclaimed = reclaim_high(memcg,
2673 in_retry ? SWAP_CLUSTER_MAX : nr_pages,
2677 * memory.high is breached and reclaim is unable to keep up. Throttle
2678 * allocators proactively to slow down excessive growth.
2680 penalty_jiffies = calculate_high_delay(memcg, nr_pages,
2681 mem_find_max_overage(memcg));
2683 penalty_jiffies += calculate_high_delay(memcg, nr_pages,
2684 swap_find_max_overage(memcg));
2687 * Clamp the max delay per usermode return so as to still keep the
2688 * application moving forwards and also permit diagnostics, albeit
2691 penalty_jiffies = min(penalty_jiffies, MEMCG_MAX_HIGH_DELAY_JIFFIES);
2694 * Don't sleep if the amount of jiffies this memcg owes us is so low
2695 * that it's not even worth doing, in an attempt to be nice to those who
2696 * go only a small amount over their memory.high value and maybe haven't
2697 * been aggressively reclaimed enough yet.
2699 if (penalty_jiffies <= HZ / 100)
2703 * If reclaim is making forward progress but we're still over
2704 * memory.high, we want to encourage that rather than doing allocator
2707 if (nr_reclaimed || nr_retries--) {
2713 * Reclaim didn't manage to push usage below the limit, slow
2714 * this allocating task down.
2716 * If we exit early, we're guaranteed to die (since
2717 * schedule_timeout_killable sets TASK_KILLABLE). This means we don't
2718 * need to account for any ill-begotten jiffies to pay them off later.
2720 psi_memstall_enter(&pflags);
2721 schedule_timeout_killable(penalty_jiffies);
2722 psi_memstall_leave(&pflags);
2725 css_put(&memcg->css);
2728 static int try_charge_memcg(struct mem_cgroup *memcg, gfp_t gfp_mask,
2729 unsigned int nr_pages)
2731 unsigned int batch = max(MEMCG_CHARGE_BATCH, nr_pages);
2732 int nr_retries = MAX_RECLAIM_RETRIES;
2733 struct mem_cgroup *mem_over_limit;
2734 struct page_counter *counter;
2735 unsigned long nr_reclaimed;
2736 bool passed_oom = false;
2737 unsigned int reclaim_options = MEMCG_RECLAIM_MAY_SWAP;
2738 bool drained = false;
2739 bool raised_max_event = false;
2740 unsigned long pflags;
2743 if (consume_stock(memcg, nr_pages))
2746 if (!do_memsw_account() ||
2747 page_counter_try_charge(&memcg->memsw, batch, &counter)) {
2748 if (page_counter_try_charge(&memcg->memory, batch, &counter))
2750 if (do_memsw_account())
2751 page_counter_uncharge(&memcg->memsw, batch);
2752 mem_over_limit = mem_cgroup_from_counter(counter, memory);
2754 mem_over_limit = mem_cgroup_from_counter(counter, memsw);
2755 reclaim_options &= ~MEMCG_RECLAIM_MAY_SWAP;
2758 if (batch > nr_pages) {
2764 * Prevent unbounded recursion when reclaim operations need to
2765 * allocate memory. This might exceed the limits temporarily,
2766 * but we prefer facilitating memory reclaim and getting back
2767 * under the limit over triggering OOM kills in these cases.
2769 if (unlikely(current->flags & PF_MEMALLOC))
2772 if (unlikely(task_in_memcg_oom(current)))
2775 if (!gfpflags_allow_blocking(gfp_mask))
2778 memcg_memory_event(mem_over_limit, MEMCG_MAX);
2779 raised_max_event = true;
2781 psi_memstall_enter(&pflags);
2782 nr_reclaimed = try_to_free_mem_cgroup_pages(mem_over_limit, nr_pages,
2783 gfp_mask, reclaim_options);
2784 psi_memstall_leave(&pflags);
2786 if (mem_cgroup_margin(mem_over_limit) >= nr_pages)
2790 drain_all_stock(mem_over_limit);
2795 if (gfp_mask & __GFP_NORETRY)
2798 * Even though the limit is exceeded at this point, reclaim
2799 * may have been able to free some pages. Retry the charge
2800 * before killing the task.
2802 * Only for regular pages, though: huge pages are rather
2803 * unlikely to succeed so close to the limit, and we fall back
2804 * to regular pages anyway in case of failure.
2806 if (nr_reclaimed && nr_pages <= (1 << PAGE_ALLOC_COSTLY_ORDER))
2809 * At task move, charge accounts can be doubly counted. So, it's
2810 * better to wait until the end of task_move if something is going on.
2812 if (mem_cgroup_wait_acct_move(mem_over_limit))
2818 if (gfp_mask & __GFP_RETRY_MAYFAIL)
2821 /* Avoid endless loop for tasks bypassed by the oom killer */
2822 if (passed_oom && task_is_dying())
2826 * keep retrying as long as the memcg oom killer is able to make
2827 * a forward progress or bypass the charge if the oom killer
2828 * couldn't make any progress.
2830 if (mem_cgroup_oom(mem_over_limit, gfp_mask,
2831 get_order(nr_pages * PAGE_SIZE))) {
2833 nr_retries = MAX_RECLAIM_RETRIES;
2838 * Memcg doesn't have a dedicated reserve for atomic
2839 * allocations. But like the global atomic pool, we need to
2840 * put the burden of reclaim on regular allocation requests
2841 * and let these go through as privileged allocations.
2843 if (!(gfp_mask & (__GFP_NOFAIL | __GFP_HIGH)))
2847 * If the allocation has to be enforced, don't forget to raise
2848 * a MEMCG_MAX event.
2850 if (!raised_max_event)
2851 memcg_memory_event(mem_over_limit, MEMCG_MAX);
2854 * The allocation either can't fail or will lead to more memory
2855 * being freed very soon. Allow memory usage go over the limit
2856 * temporarily by force charging it.
2858 page_counter_charge(&memcg->memory, nr_pages);
2859 if (do_memsw_account())
2860 page_counter_charge(&memcg->memsw, nr_pages);
2865 if (batch > nr_pages)
2866 refill_stock(memcg, batch - nr_pages);
2869 * If the hierarchy is above the normal consumption range, schedule
2870 * reclaim on returning to userland. We can perform reclaim here
2871 * if __GFP_RECLAIM but let's always punt for simplicity and so that
2872 * GFP_KERNEL can consistently be used during reclaim. @memcg is
2873 * not recorded as it most likely matches current's and won't
2874 * change in the meantime. As high limit is checked again before
2875 * reclaim, the cost of mismatch is negligible.
2878 bool mem_high, swap_high;
2880 mem_high = page_counter_read(&memcg->memory) >
2881 READ_ONCE(memcg->memory.high);
2882 swap_high = page_counter_read(&memcg->swap) >
2883 READ_ONCE(memcg->swap.high);
2885 /* Don't bother a random interrupted task */
2888 schedule_work(&memcg->high_work);
2894 if (mem_high || swap_high) {
2896 * The allocating tasks in this cgroup will need to do
2897 * reclaim or be throttled to prevent further growth
2898 * of the memory or swap footprints.
2900 * Target some best-effort fairness between the tasks,
2901 * and distribute reclaim work and delay penalties
2902 * based on how much each task is actually allocating.
2904 current->memcg_nr_pages_over_high += batch;
2905 set_notify_resume(current);
2908 } while ((memcg = parent_mem_cgroup(memcg)));
2911 * Reclaim is set up above to be called from the userland
2912 * return path. But also attempt synchronous reclaim to avoid
2913 * excessive overrun while the task is still inside the
2914 * kernel. If this is successful, the return path will see it
2915 * when it rechecks the overage and simply bail out.
2917 if (current->memcg_nr_pages_over_high > MEMCG_CHARGE_BATCH &&
2918 !(current->flags & PF_MEMALLOC) &&
2919 gfpflags_allow_blocking(gfp_mask))
2920 mem_cgroup_handle_over_high(gfp_mask);
2924 static inline int try_charge(struct mem_cgroup *memcg, gfp_t gfp_mask,
2925 unsigned int nr_pages)
2927 if (mem_cgroup_is_root(memcg))
2930 return try_charge_memcg(memcg, gfp_mask, nr_pages);
2934 * mem_cgroup_cancel_charge() - cancel an uncommitted try_charge() call.
2935 * @memcg: memcg previously charged.
2936 * @nr_pages: number of pages previously charged.
2938 void mem_cgroup_cancel_charge(struct mem_cgroup *memcg, unsigned int nr_pages)
2940 if (mem_cgroup_is_root(memcg))
2943 page_counter_uncharge(&memcg->memory, nr_pages);
2944 if (do_memsw_account())
2945 page_counter_uncharge(&memcg->memsw, nr_pages);
2948 static void commit_charge(struct folio *folio, struct mem_cgroup *memcg)
2950 VM_BUG_ON_FOLIO(folio_memcg(folio), folio);
2952 * Any of the following ensures page's memcg stability:
2956 * - folio_memcg_lock()
2957 * - exclusive reference
2958 * - mem_cgroup_trylock_pages()
2960 folio->memcg_data = (unsigned long)memcg;
2964 * mem_cgroup_commit_charge - commit a previously successful try_charge().
2965 * @folio: folio to commit the charge to.
2966 * @memcg: memcg previously charged.
2968 void mem_cgroup_commit_charge(struct folio *folio, struct mem_cgroup *memcg)
2970 css_get(&memcg->css);
2971 commit_charge(folio, memcg);
2973 local_irq_disable();
2974 mem_cgroup_charge_statistics(memcg, folio_nr_pages(folio));
2975 memcg_check_events(memcg, folio_nid(folio));
2979 #ifdef CONFIG_MEMCG_KMEM
2981 * The allocated objcg pointers array is not accounted directly.
2982 * Moreover, it should not come from DMA buffer and is not readily
2983 * reclaimable. So those GFP bits should be masked off.
2985 #define OBJCGS_CLEAR_MASK (__GFP_DMA | __GFP_RECLAIMABLE | \
2986 __GFP_ACCOUNT | __GFP_NOFAIL)
2989 * mod_objcg_mlstate() may be called with irq enabled, so
2990 * mod_memcg_lruvec_state() should be used.
2992 static inline void mod_objcg_mlstate(struct obj_cgroup *objcg,
2993 struct pglist_data *pgdat,
2994 enum node_stat_item idx, int nr)
2996 struct mem_cgroup *memcg;
2997 struct lruvec *lruvec;
3000 memcg = obj_cgroup_memcg(objcg);
3001 lruvec = mem_cgroup_lruvec(memcg, pgdat);
3002 mod_memcg_lruvec_state(lruvec, idx, nr);
3006 int memcg_alloc_slab_cgroups(struct slab *slab, struct kmem_cache *s,
3007 gfp_t gfp, bool new_slab)
3009 unsigned int objects = objs_per_slab(s, slab);
3010 unsigned long memcg_data;
3013 gfp &= ~OBJCGS_CLEAR_MASK;
3014 vec = kcalloc_node(objects, sizeof(struct obj_cgroup *), gfp,
3019 memcg_data = (unsigned long) vec | MEMCG_DATA_OBJCGS;
3022 * If the slab is brand new and nobody can yet access its
3023 * memcg_data, no synchronization is required and memcg_data can
3024 * be simply assigned.
3026 slab->memcg_data = memcg_data;
3027 } else if (cmpxchg(&slab->memcg_data, 0, memcg_data)) {
3029 * If the slab is already in use, somebody can allocate and
3030 * assign obj_cgroups in parallel. In this case the existing
3031 * objcg vector should be reused.
3037 kmemleak_not_leak(vec);
3041 static __always_inline
3042 struct mem_cgroup *mem_cgroup_from_obj_folio(struct folio *folio, void *p)
3045 * Slab objects are accounted individually, not per-page.
3046 * Memcg membership data for each individual object is saved in
3049 if (folio_test_slab(folio)) {
3050 struct obj_cgroup **objcgs;
3054 slab = folio_slab(folio);
3055 objcgs = slab_objcgs(slab);
3059 off = obj_to_index(slab->slab_cache, slab, p);
3061 return obj_cgroup_memcg(objcgs[off]);
3067 * folio_memcg_check() is used here, because in theory we can encounter
3068 * a folio where the slab flag has been cleared already, but
3069 * slab->memcg_data has not been freed yet
3070 * folio_memcg_check() will guarantee that a proper memory
3071 * cgroup pointer or NULL will be returned.
3073 return folio_memcg_check(folio);
3077 * Returns a pointer to the memory cgroup to which the kernel object is charged.
3079 * A passed kernel object can be a slab object, vmalloc object or a generic
3080 * kernel page, so different mechanisms for getting the memory cgroup pointer
3083 * In certain cases (e.g. kernel stacks or large kmallocs with SLUB) the caller
3084 * can not know for sure how the kernel object is implemented.
3085 * mem_cgroup_from_obj() can be safely used in such cases.
3087 * The caller must ensure the memcg lifetime, e.g. by taking rcu_read_lock(),
3088 * cgroup_mutex, etc.
3090 struct mem_cgroup *mem_cgroup_from_obj(void *p)
3092 struct folio *folio;
3094 if (mem_cgroup_disabled())
3097 if (unlikely(is_vmalloc_addr(p)))
3098 folio = page_folio(vmalloc_to_page(p));
3100 folio = virt_to_folio(p);
3102 return mem_cgroup_from_obj_folio(folio, p);
3106 * Returns a pointer to the memory cgroup to which the kernel object is charged.
3107 * Similar to mem_cgroup_from_obj(), but faster and not suitable for objects,
3108 * allocated using vmalloc().
3110 * A passed kernel object must be a slab object or a generic kernel page.
3112 * The caller must ensure the memcg lifetime, e.g. by taking rcu_read_lock(),
3113 * cgroup_mutex, etc.
3115 struct mem_cgroup *mem_cgroup_from_slab_obj(void *p)
3117 if (mem_cgroup_disabled())
3120 return mem_cgroup_from_obj_folio(virt_to_folio(p), p);
3123 static struct obj_cgroup *__get_obj_cgroup_from_memcg(struct mem_cgroup *memcg)
3125 struct obj_cgroup *objcg = NULL;
3127 for (; !mem_cgroup_is_root(memcg); memcg = parent_mem_cgroup(memcg)) {
3128 objcg = rcu_dereference(memcg->objcg);
3129 if (likely(objcg && obj_cgroup_tryget(objcg)))
3136 static struct obj_cgroup *current_objcg_update(void)
3138 struct mem_cgroup *memcg;
3139 struct obj_cgroup *old, *objcg = NULL;
3142 /* Atomically drop the update bit. */
3143 old = xchg(¤t->objcg, NULL);
3145 old = (struct obj_cgroup *)
3146 ((unsigned long)old & ~CURRENT_OBJCG_UPDATE_FLAG);
3148 obj_cgroup_put(old);
3153 /* If new objcg is NULL, no reason for the second atomic update. */
3154 if (!current->mm || (current->flags & PF_KTHREAD))
3158 * Release the objcg pointer from the previous iteration,
3159 * if try_cmpxcg() below fails.
3161 if (unlikely(objcg)) {
3162 obj_cgroup_put(objcg);
3167 * Obtain the new objcg pointer. The current task can be
3168 * asynchronously moved to another memcg and the previous
3169 * memcg can be offlined. So let's get the memcg pointer
3170 * and try get a reference to objcg under a rcu read lock.
3174 memcg = mem_cgroup_from_task(current);
3175 objcg = __get_obj_cgroup_from_memcg(memcg);
3179 * Try set up a new objcg pointer atomically. If it
3180 * fails, it means the update flag was set concurrently, so
3181 * the whole procedure should be repeated.
3183 } while (!try_cmpxchg(¤t->objcg, &old, objcg));
3188 __always_inline struct obj_cgroup *current_obj_cgroup(void)
3190 struct mem_cgroup *memcg;
3191 struct obj_cgroup *objcg;
3194 memcg = current->active_memcg;
3195 if (unlikely(memcg))
3198 objcg = READ_ONCE(current->objcg);
3199 if (unlikely((unsigned long)objcg & CURRENT_OBJCG_UPDATE_FLAG))
3200 objcg = current_objcg_update();
3202 * Objcg reference is kept by the task, so it's safe
3203 * to use the objcg by the current task.
3208 memcg = this_cpu_read(int_active_memcg);
3209 if (unlikely(memcg))
3216 for (; !mem_cgroup_is_root(memcg); memcg = parent_mem_cgroup(memcg)) {
3218 * Memcg pointer is protected by scope (see set_active_memcg())
3219 * and is pinning the corresponding objcg, so objcg can't go
3220 * away and can be used within the scope without any additional
3223 objcg = rcu_dereference_check(memcg->objcg, 1);
3231 struct obj_cgroup *get_obj_cgroup_from_folio(struct folio *folio)
3233 struct obj_cgroup *objcg;
3235 if (!memcg_kmem_online())
3238 if (folio_memcg_kmem(folio)) {
3239 objcg = __folio_objcg(folio);
3240 obj_cgroup_get(objcg);
3242 struct mem_cgroup *memcg;
3245 memcg = __folio_memcg(folio);
3247 objcg = __get_obj_cgroup_from_memcg(memcg);
3255 static void memcg_account_kmem(struct mem_cgroup *memcg, int nr_pages)
3257 mod_memcg_state(memcg, MEMCG_KMEM, nr_pages);
3258 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) {
3260 page_counter_charge(&memcg->kmem, nr_pages);
3262 page_counter_uncharge(&memcg->kmem, -nr_pages);
3268 * obj_cgroup_uncharge_pages: uncharge a number of kernel pages from a objcg
3269 * @objcg: object cgroup to uncharge
3270 * @nr_pages: number of pages to uncharge
3272 static void obj_cgroup_uncharge_pages(struct obj_cgroup *objcg,
3273 unsigned int nr_pages)
3275 struct mem_cgroup *memcg;
3277 memcg = get_mem_cgroup_from_objcg(objcg);
3279 memcg_account_kmem(memcg, -nr_pages);
3280 refill_stock(memcg, nr_pages);
3282 css_put(&memcg->css);
3286 * obj_cgroup_charge_pages: charge a number of kernel pages to a objcg
3287 * @objcg: object cgroup to charge
3288 * @gfp: reclaim mode
3289 * @nr_pages: number of pages to charge
3291 * Returns 0 on success, an error code on failure.
3293 static int obj_cgroup_charge_pages(struct obj_cgroup *objcg, gfp_t gfp,
3294 unsigned int nr_pages)
3296 struct mem_cgroup *memcg;
3299 memcg = get_mem_cgroup_from_objcg(objcg);
3301 ret = try_charge_memcg(memcg, gfp, nr_pages);
3305 memcg_account_kmem(memcg, nr_pages);
3307 css_put(&memcg->css);
3313 * __memcg_kmem_charge_page: charge a kmem page to the current memory cgroup
3314 * @page: page to charge
3315 * @gfp: reclaim mode
3316 * @order: allocation order
3318 * Returns 0 on success, an error code on failure.
3320 int __memcg_kmem_charge_page(struct page *page, gfp_t gfp, int order)
3322 struct obj_cgroup *objcg;
3325 objcg = current_obj_cgroup();
3327 ret = obj_cgroup_charge_pages(objcg, gfp, 1 << order);
3329 obj_cgroup_get(objcg);
3330 page->memcg_data = (unsigned long)objcg |
3339 * __memcg_kmem_uncharge_page: uncharge a kmem page
3340 * @page: page to uncharge
3341 * @order: allocation order
3343 void __memcg_kmem_uncharge_page(struct page *page, int order)
3345 struct folio *folio = page_folio(page);
3346 struct obj_cgroup *objcg;
3347 unsigned int nr_pages = 1 << order;
3349 if (!folio_memcg_kmem(folio))
3352 objcg = __folio_objcg(folio);
3353 obj_cgroup_uncharge_pages(objcg, nr_pages);
3354 folio->memcg_data = 0;
3355 obj_cgroup_put(objcg);
3358 void mod_objcg_state(struct obj_cgroup *objcg, struct pglist_data *pgdat,
3359 enum node_stat_item idx, int nr)
3361 struct memcg_stock_pcp *stock;
3362 struct obj_cgroup *old = NULL;
3363 unsigned long flags;
3366 local_lock_irqsave(&memcg_stock.stock_lock, flags);
3367 stock = this_cpu_ptr(&memcg_stock);
3370 * Save vmstat data in stock and skip vmstat array update unless
3371 * accumulating over a page of vmstat data or when pgdat or idx
3374 if (READ_ONCE(stock->cached_objcg) != objcg) {
3375 old = drain_obj_stock(stock);
3376 obj_cgroup_get(objcg);
3377 stock->nr_bytes = atomic_read(&objcg->nr_charged_bytes)
3378 ? atomic_xchg(&objcg->nr_charged_bytes, 0) : 0;
3379 WRITE_ONCE(stock->cached_objcg, objcg);
3380 stock->cached_pgdat = pgdat;
3381 } else if (stock->cached_pgdat != pgdat) {
3382 /* Flush the existing cached vmstat data */
3383 struct pglist_data *oldpg = stock->cached_pgdat;
3385 if (stock->nr_slab_reclaimable_b) {
3386 mod_objcg_mlstate(objcg, oldpg, NR_SLAB_RECLAIMABLE_B,
3387 stock->nr_slab_reclaimable_b);
3388 stock->nr_slab_reclaimable_b = 0;
3390 if (stock->nr_slab_unreclaimable_b) {
3391 mod_objcg_mlstate(objcg, oldpg, NR_SLAB_UNRECLAIMABLE_B,
3392 stock->nr_slab_unreclaimable_b);
3393 stock->nr_slab_unreclaimable_b = 0;
3395 stock->cached_pgdat = pgdat;
3398 bytes = (idx == NR_SLAB_RECLAIMABLE_B) ? &stock->nr_slab_reclaimable_b
3399 : &stock->nr_slab_unreclaimable_b;
3401 * Even for large object >= PAGE_SIZE, the vmstat data will still be
3402 * cached locally at least once before pushing it out.
3409 if (abs(*bytes) > PAGE_SIZE) {
3417 mod_objcg_mlstate(objcg, pgdat, idx, nr);
3419 local_unlock_irqrestore(&memcg_stock.stock_lock, flags);
3421 obj_cgroup_put(old);
3424 static bool consume_obj_stock(struct obj_cgroup *objcg, unsigned int nr_bytes)
3426 struct memcg_stock_pcp *stock;
3427 unsigned long flags;
3430 local_lock_irqsave(&memcg_stock.stock_lock, flags);
3432 stock = this_cpu_ptr(&memcg_stock);
3433 if (objcg == READ_ONCE(stock->cached_objcg) && stock->nr_bytes >= nr_bytes) {
3434 stock->nr_bytes -= nr_bytes;
3438 local_unlock_irqrestore(&memcg_stock.stock_lock, flags);
3443 static struct obj_cgroup *drain_obj_stock(struct memcg_stock_pcp *stock)
3445 struct obj_cgroup *old = READ_ONCE(stock->cached_objcg);
3450 if (stock->nr_bytes) {
3451 unsigned int nr_pages = stock->nr_bytes >> PAGE_SHIFT;
3452 unsigned int nr_bytes = stock->nr_bytes & (PAGE_SIZE - 1);
3455 struct mem_cgroup *memcg;
3457 memcg = get_mem_cgroup_from_objcg(old);
3459 memcg_account_kmem(memcg, -nr_pages);
3460 __refill_stock(memcg, nr_pages);
3462 css_put(&memcg->css);
3466 * The leftover is flushed to the centralized per-memcg value.
3467 * On the next attempt to refill obj stock it will be moved
3468 * to a per-cpu stock (probably, on an other CPU), see
3469 * refill_obj_stock().
3471 * How often it's flushed is a trade-off between the memory
3472 * limit enforcement accuracy and potential CPU contention,
3473 * so it might be changed in the future.
3475 atomic_add(nr_bytes, &old->nr_charged_bytes);
3476 stock->nr_bytes = 0;
3480 * Flush the vmstat data in current stock
3482 if (stock->nr_slab_reclaimable_b || stock->nr_slab_unreclaimable_b) {
3483 if (stock->nr_slab_reclaimable_b) {
3484 mod_objcg_mlstate(old, stock->cached_pgdat,
3485 NR_SLAB_RECLAIMABLE_B,
3486 stock->nr_slab_reclaimable_b);
3487 stock->nr_slab_reclaimable_b = 0;
3489 if (stock->nr_slab_unreclaimable_b) {
3490 mod_objcg_mlstate(old, stock->cached_pgdat,
3491 NR_SLAB_UNRECLAIMABLE_B,
3492 stock->nr_slab_unreclaimable_b);
3493 stock->nr_slab_unreclaimable_b = 0;
3495 stock->cached_pgdat = NULL;
3498 WRITE_ONCE(stock->cached_objcg, NULL);
3500 * The `old' objects needs to be released by the caller via
3501 * obj_cgroup_put() outside of memcg_stock_pcp::stock_lock.
3506 static bool obj_stock_flush_required(struct memcg_stock_pcp *stock,
3507 struct mem_cgroup *root_memcg)
3509 struct obj_cgroup *objcg = READ_ONCE(stock->cached_objcg);
3510 struct mem_cgroup *memcg;
3513 memcg = obj_cgroup_memcg(objcg);
3514 if (memcg && mem_cgroup_is_descendant(memcg, root_memcg))
3521 static void refill_obj_stock(struct obj_cgroup *objcg, unsigned int nr_bytes,
3522 bool allow_uncharge)
3524 struct memcg_stock_pcp *stock;
3525 struct obj_cgroup *old = NULL;
3526 unsigned long flags;
3527 unsigned int nr_pages = 0;
3529 local_lock_irqsave(&memcg_stock.stock_lock, flags);
3531 stock = this_cpu_ptr(&memcg_stock);
3532 if (READ_ONCE(stock->cached_objcg) != objcg) { /* reset if necessary */
3533 old = drain_obj_stock(stock);
3534 obj_cgroup_get(objcg);
3535 WRITE_ONCE(stock->cached_objcg, objcg);
3536 stock->nr_bytes = atomic_read(&objcg->nr_charged_bytes)
3537 ? atomic_xchg(&objcg->nr_charged_bytes, 0) : 0;
3538 allow_uncharge = true; /* Allow uncharge when objcg changes */
3540 stock->nr_bytes += nr_bytes;
3542 if (allow_uncharge && (stock->nr_bytes > PAGE_SIZE)) {
3543 nr_pages = stock->nr_bytes >> PAGE_SHIFT;
3544 stock->nr_bytes &= (PAGE_SIZE - 1);
3547 local_unlock_irqrestore(&memcg_stock.stock_lock, flags);
3549 obj_cgroup_put(old);
3552 obj_cgroup_uncharge_pages(objcg, nr_pages);
3555 int obj_cgroup_charge(struct obj_cgroup *objcg, gfp_t gfp, size_t size)
3557 unsigned int nr_pages, nr_bytes;
3560 if (consume_obj_stock(objcg, size))
3564 * In theory, objcg->nr_charged_bytes can have enough
3565 * pre-charged bytes to satisfy the allocation. However,
3566 * flushing objcg->nr_charged_bytes requires two atomic
3567 * operations, and objcg->nr_charged_bytes can't be big.
3568 * The shared objcg->nr_charged_bytes can also become a
3569 * performance bottleneck if all tasks of the same memcg are
3570 * trying to update it. So it's better to ignore it and try
3571 * grab some new pages. The stock's nr_bytes will be flushed to
3572 * objcg->nr_charged_bytes later on when objcg changes.
3574 * The stock's nr_bytes may contain enough pre-charged bytes
3575 * to allow one less page from being charged, but we can't rely
3576 * on the pre-charged bytes not being changed outside of
3577 * consume_obj_stock() or refill_obj_stock(). So ignore those
3578 * pre-charged bytes as well when charging pages. To avoid a
3579 * page uncharge right after a page charge, we set the
3580 * allow_uncharge flag to false when calling refill_obj_stock()
3581 * to temporarily allow the pre-charged bytes to exceed the page
3582 * size limit. The maximum reachable value of the pre-charged
3583 * bytes is (sizeof(object) + PAGE_SIZE - 2) if there is no data
3586 nr_pages = size >> PAGE_SHIFT;
3587 nr_bytes = size & (PAGE_SIZE - 1);
3592 ret = obj_cgroup_charge_pages(objcg, gfp, nr_pages);
3593 if (!ret && nr_bytes)
3594 refill_obj_stock(objcg, PAGE_SIZE - nr_bytes, false);
3599 void obj_cgroup_uncharge(struct obj_cgroup *objcg, size_t size)
3601 refill_obj_stock(objcg, size, true);
3604 #endif /* CONFIG_MEMCG_KMEM */
3607 * Because page_memcg(head) is not set on tails, set it now.
3609 void split_page_memcg(struct page *head, unsigned int nr)
3611 struct folio *folio = page_folio(head);
3612 struct mem_cgroup *memcg = folio_memcg(folio);
3615 if (mem_cgroup_disabled() || !memcg)
3618 for (i = 1; i < nr; i++)
3619 folio_page(folio, i)->memcg_data = folio->memcg_data;
3621 if (folio_memcg_kmem(folio))
3622 obj_cgroup_get_many(__folio_objcg(folio), nr - 1);
3624 css_get_many(&memcg->css, nr - 1);
3629 * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record.
3630 * @entry: swap entry to be moved
3631 * @from: mem_cgroup which the entry is moved from
3632 * @to: mem_cgroup which the entry is moved to
3634 * It succeeds only when the swap_cgroup's record for this entry is the same
3635 * as the mem_cgroup's id of @from.
3637 * Returns 0 on success, -EINVAL on failure.
3639 * The caller must have charged to @to, IOW, called page_counter_charge() about
3640 * both res and memsw, and called css_get().
3642 static int mem_cgroup_move_swap_account(swp_entry_t entry,
3643 struct mem_cgroup *from, struct mem_cgroup *to)
3645 unsigned short old_id, new_id;
3647 old_id = mem_cgroup_id(from);
3648 new_id = mem_cgroup_id(to);
3650 if (swap_cgroup_cmpxchg(entry, old_id, new_id) == old_id) {
3651 mod_memcg_state(from, MEMCG_SWAP, -1);
3652 mod_memcg_state(to, MEMCG_SWAP, 1);
3658 static inline int mem_cgroup_move_swap_account(swp_entry_t entry,
3659 struct mem_cgroup *from, struct mem_cgroup *to)
3665 static DEFINE_MUTEX(memcg_max_mutex);
3667 static int mem_cgroup_resize_max(struct mem_cgroup *memcg,
3668 unsigned long max, bool memsw)
3670 bool enlarge = false;
3671 bool drained = false;
3673 bool limits_invariant;
3674 struct page_counter *counter = memsw ? &memcg->memsw : &memcg->memory;
3677 if (signal_pending(current)) {
3682 mutex_lock(&memcg_max_mutex);
3684 * Make sure that the new limit (memsw or memory limit) doesn't
3685 * break our basic invariant rule memory.max <= memsw.max.
3687 limits_invariant = memsw ? max >= READ_ONCE(memcg->memory.max) :
3688 max <= memcg->memsw.max;
3689 if (!limits_invariant) {
3690 mutex_unlock(&memcg_max_mutex);
3694 if (max > counter->max)
3696 ret = page_counter_set_max(counter, max);
3697 mutex_unlock(&memcg_max_mutex);
3703 drain_all_stock(memcg);
3708 if (!try_to_free_mem_cgroup_pages(memcg, 1, GFP_KERNEL,
3709 memsw ? 0 : MEMCG_RECLAIM_MAY_SWAP)) {
3715 if (!ret && enlarge)
3716 memcg_oom_recover(memcg);
3721 unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order,
3723 unsigned long *total_scanned)
3725 unsigned long nr_reclaimed = 0;
3726 struct mem_cgroup_per_node *mz, *next_mz = NULL;
3727 unsigned long reclaimed;
3729 struct mem_cgroup_tree_per_node *mctz;
3730 unsigned long excess;
3732 if (lru_gen_enabled())
3738 mctz = soft_limit_tree.rb_tree_per_node[pgdat->node_id];
3741 * Do not even bother to check the largest node if the root
3742 * is empty. Do it lockless to prevent lock bouncing. Races
3743 * are acceptable as soft limit is best effort anyway.
3745 if (!mctz || RB_EMPTY_ROOT(&mctz->rb_root))
3749 * This loop can run a while, specially if mem_cgroup's continuously
3750 * keep exceeding their soft limit and putting the system under
3757 mz = mem_cgroup_largest_soft_limit_node(mctz);
3761 reclaimed = mem_cgroup_soft_reclaim(mz->memcg, pgdat,
3762 gfp_mask, total_scanned);
3763 nr_reclaimed += reclaimed;
3764 spin_lock_irq(&mctz->lock);
3767 * If we failed to reclaim anything from this memory cgroup
3768 * it is time to move on to the next cgroup
3772 next_mz = __mem_cgroup_largest_soft_limit_node(mctz);
3774 excess = soft_limit_excess(mz->memcg);
3776 * One school of thought says that we should not add
3777 * back the node to the tree if reclaim returns 0.
3778 * But our reclaim could return 0, simply because due
3779 * to priority we are exposing a smaller subset of
3780 * memory to reclaim from. Consider this as a longer
3783 /* If excess == 0, no tree ops */
3784 __mem_cgroup_insert_exceeded(mz, mctz, excess);
3785 spin_unlock_irq(&mctz->lock);
3786 css_put(&mz->memcg->css);
3789 * Could not reclaim anything and there are no more
3790 * mem cgroups to try or we seem to be looping without
3791 * reclaiming anything.
3793 if (!nr_reclaimed &&
3795 loop > MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS))
3797 } while (!nr_reclaimed);
3799 css_put(&next_mz->memcg->css);
3800 return nr_reclaimed;
3804 * Reclaims as many pages from the given memcg as possible.
3806 * Caller is responsible for holding css reference for memcg.
3808 static int mem_cgroup_force_empty(struct mem_cgroup *memcg)
3810 int nr_retries = MAX_RECLAIM_RETRIES;
3812 /* we call try-to-free pages for make this cgroup empty */
3813 lru_add_drain_all();
3815 drain_all_stock(memcg);
3817 /* try to free all pages in this cgroup */
3818 while (nr_retries && page_counter_read(&memcg->memory)) {
3819 if (signal_pending(current))
3822 if (!try_to_free_mem_cgroup_pages(memcg, 1, GFP_KERNEL,
3823 MEMCG_RECLAIM_MAY_SWAP))
3830 static ssize_t mem_cgroup_force_empty_write(struct kernfs_open_file *of,
3831 char *buf, size_t nbytes,
3834 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
3836 if (mem_cgroup_is_root(memcg))
3838 return mem_cgroup_force_empty(memcg) ?: nbytes;
3841 static u64 mem_cgroup_hierarchy_read(struct cgroup_subsys_state *css,
3847 static int mem_cgroup_hierarchy_write(struct cgroup_subsys_state *css,
3848 struct cftype *cft, u64 val)
3853 pr_warn_once("Non-hierarchical mode is deprecated. "
3854 "Please report your usecase to linux-mm@kvack.org if you "
3855 "depend on this functionality.\n");
3860 static unsigned long mem_cgroup_usage(struct mem_cgroup *memcg, bool swap)
3864 if (mem_cgroup_is_root(memcg)) {
3866 * Approximate root's usage from global state. This isn't
3867 * perfect, but the root usage was always an approximation.
3869 val = global_node_page_state(NR_FILE_PAGES) +
3870 global_node_page_state(NR_ANON_MAPPED);
3872 val += total_swap_pages - get_nr_swap_pages();
3875 val = page_counter_read(&memcg->memory);
3877 val = page_counter_read(&memcg->memsw);
3890 static u64 mem_cgroup_read_u64(struct cgroup_subsys_state *css,
3893 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
3894 struct page_counter *counter;
3896 switch (MEMFILE_TYPE(cft->private)) {
3898 counter = &memcg->memory;
3901 counter = &memcg->memsw;
3904 counter = &memcg->kmem;
3907 counter = &memcg->tcpmem;
3913 switch (MEMFILE_ATTR(cft->private)) {
3915 if (counter == &memcg->memory)
3916 return (u64)mem_cgroup_usage(memcg, false) * PAGE_SIZE;
3917 if (counter == &memcg->memsw)
3918 return (u64)mem_cgroup_usage(memcg, true) * PAGE_SIZE;
3919 return (u64)page_counter_read(counter) * PAGE_SIZE;
3921 return (u64)counter->max * PAGE_SIZE;
3923 return (u64)counter->watermark * PAGE_SIZE;
3925 return counter->failcnt;
3926 case RES_SOFT_LIMIT:
3927 return (u64)READ_ONCE(memcg->soft_limit) * PAGE_SIZE;
3934 * This function doesn't do anything useful. Its only job is to provide a read
3935 * handler for a file so that cgroup_file_mode() will add read permissions.
3937 static int mem_cgroup_dummy_seq_show(__always_unused struct seq_file *m,
3938 __always_unused void *v)
3943 #ifdef CONFIG_MEMCG_KMEM
3944 static int memcg_online_kmem(struct mem_cgroup *memcg)
3946 struct obj_cgroup *objcg;
3948 if (mem_cgroup_kmem_disabled())
3951 if (unlikely(mem_cgroup_is_root(memcg)))
3954 objcg = obj_cgroup_alloc();
3958 objcg->memcg = memcg;
3959 rcu_assign_pointer(memcg->objcg, objcg);
3960 obj_cgroup_get(objcg);
3961 memcg->orig_objcg = objcg;
3963 static_branch_enable(&memcg_kmem_online_key);
3965 memcg->kmemcg_id = memcg->id.id;
3970 static void memcg_offline_kmem(struct mem_cgroup *memcg)
3972 struct mem_cgroup *parent;
3974 if (mem_cgroup_kmem_disabled())
3977 if (unlikely(mem_cgroup_is_root(memcg)))
3980 parent = parent_mem_cgroup(memcg);
3982 parent = root_mem_cgroup;
3984 memcg_reparent_objcgs(memcg, parent);
3987 * After we have finished memcg_reparent_objcgs(), all list_lrus
3988 * corresponding to this cgroup are guaranteed to remain empty.
3989 * The ordering is imposed by list_lru_node->lock taken by
3990 * memcg_reparent_list_lrus().
3992 memcg_reparent_list_lrus(memcg, parent);
3995 static int memcg_online_kmem(struct mem_cgroup *memcg)
3999 static void memcg_offline_kmem(struct mem_cgroup *memcg)
4002 #endif /* CONFIG_MEMCG_KMEM */
4004 static int memcg_update_tcp_max(struct mem_cgroup *memcg, unsigned long max)
4008 mutex_lock(&memcg_max_mutex);
4010 ret = page_counter_set_max(&memcg->tcpmem, max);
4014 if (!memcg->tcpmem_active) {
4016 * The active flag needs to be written after the static_key
4017 * update. This is what guarantees that the socket activation
4018 * function is the last one to run. See mem_cgroup_sk_alloc()
4019 * for details, and note that we don't mark any socket as
4020 * belonging to this memcg until that flag is up.
4022 * We need to do this, because static_keys will span multiple
4023 * sites, but we can't control their order. If we mark a socket
4024 * as accounted, but the accounting functions are not patched in
4025 * yet, we'll lose accounting.
4027 * We never race with the readers in mem_cgroup_sk_alloc(),
4028 * because when this value change, the code to process it is not
4031 static_branch_inc(&memcg_sockets_enabled_key);
4032 memcg->tcpmem_active = true;
4035 mutex_unlock(&memcg_max_mutex);
4040 * The user of this function is...
4043 static ssize_t mem_cgroup_write(struct kernfs_open_file *of,
4044 char *buf, size_t nbytes, loff_t off)
4046 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
4047 unsigned long nr_pages;
4050 buf = strstrip(buf);
4051 ret = page_counter_memparse(buf, "-1", &nr_pages);
4055 switch (MEMFILE_ATTR(of_cft(of)->private)) {
4057 if (mem_cgroup_is_root(memcg)) { /* Can't set limit on root */
4061 switch (MEMFILE_TYPE(of_cft(of)->private)) {
4063 ret = mem_cgroup_resize_max(memcg, nr_pages, false);
4066 ret = mem_cgroup_resize_max(memcg, nr_pages, true);
4069 pr_warn_once("kmem.limit_in_bytes is deprecated and will be removed. "
4070 "Writing any value to this file has no effect. "
4071 "Please report your usecase to linux-mm@kvack.org if you "
4072 "depend on this functionality.\n");
4076 ret = memcg_update_tcp_max(memcg, nr_pages);
4080 case RES_SOFT_LIMIT:
4081 if (IS_ENABLED(CONFIG_PREEMPT_RT)) {
4084 WRITE_ONCE(memcg->soft_limit, nr_pages);
4089 return ret ?: nbytes;
4092 static ssize_t mem_cgroup_reset(struct kernfs_open_file *of, char *buf,
4093 size_t nbytes, loff_t off)
4095 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
4096 struct page_counter *counter;
4098 switch (MEMFILE_TYPE(of_cft(of)->private)) {
4100 counter = &memcg->memory;
4103 counter = &memcg->memsw;
4106 counter = &memcg->kmem;
4109 counter = &memcg->tcpmem;
4115 switch (MEMFILE_ATTR(of_cft(of)->private)) {
4117 page_counter_reset_watermark(counter);
4120 counter->failcnt = 0;
4129 static u64 mem_cgroup_move_charge_read(struct cgroup_subsys_state *css,
4132 return mem_cgroup_from_css(css)->move_charge_at_immigrate;
4136 static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css,
4137 struct cftype *cft, u64 val)
4139 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4141 pr_warn_once("Cgroup memory moving (move_charge_at_immigrate) is deprecated. "
4142 "Please report your usecase to linux-mm@kvack.org if you "
4143 "depend on this functionality.\n");
4145 if (val & ~MOVE_MASK)
4149 * No kind of locking is needed in here, because ->can_attach() will
4150 * check this value once in the beginning of the process, and then carry
4151 * on with stale data. This means that changes to this value will only
4152 * affect task migrations starting after the change.
4154 memcg->move_charge_at_immigrate = val;
4158 static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css,
4159 struct cftype *cft, u64 val)
4167 #define LRU_ALL_FILE (BIT(LRU_INACTIVE_FILE) | BIT(LRU_ACTIVE_FILE))
4168 #define LRU_ALL_ANON (BIT(LRU_INACTIVE_ANON) | BIT(LRU_ACTIVE_ANON))
4169 #define LRU_ALL ((1 << NR_LRU_LISTS) - 1)
4171 static unsigned long mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg,
4172 int nid, unsigned int lru_mask, bool tree)
4174 struct lruvec *lruvec = mem_cgroup_lruvec(memcg, NODE_DATA(nid));
4175 unsigned long nr = 0;
4178 VM_BUG_ON((unsigned)nid >= nr_node_ids);
4181 if (!(BIT(lru) & lru_mask))
4184 nr += lruvec_page_state(lruvec, NR_LRU_BASE + lru);
4186 nr += lruvec_page_state_local(lruvec, NR_LRU_BASE + lru);
4191 static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup *memcg,
4192 unsigned int lru_mask,
4195 unsigned long nr = 0;
4199 if (!(BIT(lru) & lru_mask))
4202 nr += memcg_page_state(memcg, NR_LRU_BASE + lru);
4204 nr += memcg_page_state_local(memcg, NR_LRU_BASE + lru);
4209 static int memcg_numa_stat_show(struct seq_file *m, void *v)
4213 unsigned int lru_mask;
4216 static const struct numa_stat stats[] = {
4217 { "total", LRU_ALL },
4218 { "file", LRU_ALL_FILE },
4219 { "anon", LRU_ALL_ANON },
4220 { "unevictable", BIT(LRU_UNEVICTABLE) },
4222 const struct numa_stat *stat;
4224 struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
4226 mem_cgroup_flush_stats(memcg);
4228 for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) {
4229 seq_printf(m, "%s=%lu", stat->name,
4230 mem_cgroup_nr_lru_pages(memcg, stat->lru_mask,
4232 for_each_node_state(nid, N_MEMORY)
4233 seq_printf(m, " N%d=%lu", nid,
4234 mem_cgroup_node_nr_lru_pages(memcg, nid,
4235 stat->lru_mask, false));
4239 for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) {
4241 seq_printf(m, "hierarchical_%s=%lu", stat->name,
4242 mem_cgroup_nr_lru_pages(memcg, stat->lru_mask,
4244 for_each_node_state(nid, N_MEMORY)
4245 seq_printf(m, " N%d=%lu", nid,
4246 mem_cgroup_node_nr_lru_pages(memcg, nid,
4247 stat->lru_mask, true));
4253 #endif /* CONFIG_NUMA */
4255 static const unsigned int memcg1_stats[] = {
4258 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
4265 WORKINGSET_REFAULT_ANON,
4266 WORKINGSET_REFAULT_FILE,
4273 static const char *const memcg1_stat_names[] = {
4276 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
4283 "workingset_refault_anon",
4284 "workingset_refault_file",
4291 /* Universal VM events cgroup1 shows, original sort order */
4292 static const unsigned int memcg1_events[] = {
4299 static void memcg1_stat_format(struct mem_cgroup *memcg, struct seq_buf *s)
4301 unsigned long memory, memsw;
4302 struct mem_cgroup *mi;
4305 BUILD_BUG_ON(ARRAY_SIZE(memcg1_stat_names) != ARRAY_SIZE(memcg1_stats));
4307 mem_cgroup_flush_stats(memcg);
4309 for (i = 0; i < ARRAY_SIZE(memcg1_stats); i++) {
4312 nr = memcg_page_state_local_output(memcg, memcg1_stats[i]);
4313 seq_buf_printf(s, "%s %lu\n", memcg1_stat_names[i], nr);
4316 for (i = 0; i < ARRAY_SIZE(memcg1_events); i++)
4317 seq_buf_printf(s, "%s %lu\n", vm_event_name(memcg1_events[i]),
4318 memcg_events_local(memcg, memcg1_events[i]));
4320 for (i = 0; i < NR_LRU_LISTS; i++)
4321 seq_buf_printf(s, "%s %lu\n", lru_list_name(i),
4322 memcg_page_state_local(memcg, NR_LRU_BASE + i) *
4325 /* Hierarchical information */
4326 memory = memsw = PAGE_COUNTER_MAX;
4327 for (mi = memcg; mi; mi = parent_mem_cgroup(mi)) {
4328 memory = min(memory, READ_ONCE(mi->memory.max));
4329 memsw = min(memsw, READ_ONCE(mi->memsw.max));
4331 seq_buf_printf(s, "hierarchical_memory_limit %llu\n",
4332 (u64)memory * PAGE_SIZE);
4333 seq_buf_printf(s, "hierarchical_memsw_limit %llu\n",
4334 (u64)memsw * PAGE_SIZE);
4336 for (i = 0; i < ARRAY_SIZE(memcg1_stats); i++) {
4339 nr = memcg_page_state_output(memcg, memcg1_stats[i]);
4340 seq_buf_printf(s, "total_%s %llu\n", memcg1_stat_names[i],
4344 for (i = 0; i < ARRAY_SIZE(memcg1_events); i++)
4345 seq_buf_printf(s, "total_%s %llu\n",
4346 vm_event_name(memcg1_events[i]),
4347 (u64)memcg_events(memcg, memcg1_events[i]));
4349 for (i = 0; i < NR_LRU_LISTS; i++)
4350 seq_buf_printf(s, "total_%s %llu\n", lru_list_name(i),
4351 (u64)memcg_page_state(memcg, NR_LRU_BASE + i) *
4354 #ifdef CONFIG_DEBUG_VM
4357 struct mem_cgroup_per_node *mz;
4358 unsigned long anon_cost = 0;
4359 unsigned long file_cost = 0;
4361 for_each_online_pgdat(pgdat) {
4362 mz = memcg->nodeinfo[pgdat->node_id];
4364 anon_cost += mz->lruvec.anon_cost;
4365 file_cost += mz->lruvec.file_cost;
4367 seq_buf_printf(s, "anon_cost %lu\n", anon_cost);
4368 seq_buf_printf(s, "file_cost %lu\n", file_cost);
4373 static u64 mem_cgroup_swappiness_read(struct cgroup_subsys_state *css,
4376 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4378 return mem_cgroup_swappiness(memcg);
4381 static int mem_cgroup_swappiness_write(struct cgroup_subsys_state *css,
4382 struct cftype *cft, u64 val)
4384 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4389 if (!mem_cgroup_is_root(memcg))
4390 WRITE_ONCE(memcg->swappiness, val);
4392 WRITE_ONCE(vm_swappiness, val);
4397 static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap)
4399 struct mem_cgroup_threshold_ary *t;
4400 unsigned long usage;
4405 t = rcu_dereference(memcg->thresholds.primary);
4407 t = rcu_dereference(memcg->memsw_thresholds.primary);
4412 usage = mem_cgroup_usage(memcg, swap);
4415 * current_threshold points to threshold just below or equal to usage.
4416 * If it's not true, a threshold was crossed after last
4417 * call of __mem_cgroup_threshold().
4419 i = t->current_threshold;
4422 * Iterate backward over array of thresholds starting from
4423 * current_threshold and check if a threshold is crossed.
4424 * If none of thresholds below usage is crossed, we read
4425 * only one element of the array here.
4427 for (; i >= 0 && unlikely(t->entries[i].threshold > usage); i--)
4428 eventfd_signal(t->entries[i].eventfd);
4430 /* i = current_threshold + 1 */
4434 * Iterate forward over array of thresholds starting from
4435 * current_threshold+1 and check if a threshold is crossed.
4436 * If none of thresholds above usage is crossed, we read
4437 * only one element of the array here.
4439 for (; i < t->size && unlikely(t->entries[i].threshold <= usage); i++)
4440 eventfd_signal(t->entries[i].eventfd);
4442 /* Update current_threshold */
4443 t->current_threshold = i - 1;
4448 static void mem_cgroup_threshold(struct mem_cgroup *memcg)
4451 __mem_cgroup_threshold(memcg, false);
4452 if (do_memsw_account())
4453 __mem_cgroup_threshold(memcg, true);
4455 memcg = parent_mem_cgroup(memcg);
4459 static int compare_thresholds(const void *a, const void *b)
4461 const struct mem_cgroup_threshold *_a = a;
4462 const struct mem_cgroup_threshold *_b = b;
4464 if (_a->threshold > _b->threshold)
4467 if (_a->threshold < _b->threshold)
4473 static int mem_cgroup_oom_notify_cb(struct mem_cgroup *memcg)
4475 struct mem_cgroup_eventfd_list *ev;
4477 spin_lock(&memcg_oom_lock);
4479 list_for_each_entry(ev, &memcg->oom_notify, list)
4480 eventfd_signal(ev->eventfd);
4482 spin_unlock(&memcg_oom_lock);
4486 static void mem_cgroup_oom_notify(struct mem_cgroup *memcg)
4488 struct mem_cgroup *iter;
4490 for_each_mem_cgroup_tree(iter, memcg)
4491 mem_cgroup_oom_notify_cb(iter);
4494 static int __mem_cgroup_usage_register_event(struct mem_cgroup *memcg,
4495 struct eventfd_ctx *eventfd, const char *args, enum res_type type)
4497 struct mem_cgroup_thresholds *thresholds;
4498 struct mem_cgroup_threshold_ary *new;
4499 unsigned long threshold;
4500 unsigned long usage;
4503 ret = page_counter_memparse(args, "-1", &threshold);
4507 mutex_lock(&memcg->thresholds_lock);
4510 thresholds = &memcg->thresholds;
4511 usage = mem_cgroup_usage(memcg, false);
4512 } else if (type == _MEMSWAP) {
4513 thresholds = &memcg->memsw_thresholds;
4514 usage = mem_cgroup_usage(memcg, true);
4518 /* Check if a threshold crossed before adding a new one */
4519 if (thresholds->primary)
4520 __mem_cgroup_threshold(memcg, type == _MEMSWAP);
4522 size = thresholds->primary ? thresholds->primary->size + 1 : 1;
4524 /* Allocate memory for new array of thresholds */
4525 new = kmalloc(struct_size(new, entries, size), GFP_KERNEL);
4532 /* Copy thresholds (if any) to new array */
4533 if (thresholds->primary)
4534 memcpy(new->entries, thresholds->primary->entries,
4535 flex_array_size(new, entries, size - 1));
4537 /* Add new threshold */
4538 new->entries[size - 1].eventfd = eventfd;
4539 new->entries[size - 1].threshold = threshold;
4541 /* Sort thresholds. Registering of new threshold isn't time-critical */
4542 sort(new->entries, size, sizeof(*new->entries),
4543 compare_thresholds, NULL);
4545 /* Find current threshold */
4546 new->current_threshold = -1;
4547 for (i = 0; i < size; i++) {
4548 if (new->entries[i].threshold <= usage) {
4550 * new->current_threshold will not be used until
4551 * rcu_assign_pointer(), so it's safe to increment
4554 ++new->current_threshold;
4559 /* Free old spare buffer and save old primary buffer as spare */
4560 kfree(thresholds->spare);
4561 thresholds->spare = thresholds->primary;
4563 rcu_assign_pointer(thresholds->primary, new);
4565 /* To be sure that nobody uses thresholds */
4569 mutex_unlock(&memcg->thresholds_lock);
4574 static int mem_cgroup_usage_register_event(struct mem_cgroup *memcg,
4575 struct eventfd_ctx *eventfd, const char *args)
4577 return __mem_cgroup_usage_register_event(memcg, eventfd, args, _MEM);
4580 static int memsw_cgroup_usage_register_event(struct mem_cgroup *memcg,
4581 struct eventfd_ctx *eventfd, const char *args)
4583 return __mem_cgroup_usage_register_event(memcg, eventfd, args, _MEMSWAP);
4586 static void __mem_cgroup_usage_unregister_event(struct mem_cgroup *memcg,
4587 struct eventfd_ctx *eventfd, enum res_type type)
4589 struct mem_cgroup_thresholds *thresholds;
4590 struct mem_cgroup_threshold_ary *new;
4591 unsigned long usage;
4592 int i, j, size, entries;
4594 mutex_lock(&memcg->thresholds_lock);
4597 thresholds = &memcg->thresholds;
4598 usage = mem_cgroup_usage(memcg, false);
4599 } else if (type == _MEMSWAP) {
4600 thresholds = &memcg->memsw_thresholds;
4601 usage = mem_cgroup_usage(memcg, true);
4605 if (!thresholds->primary)
4608 /* Check if a threshold crossed before removing */
4609 __mem_cgroup_threshold(memcg, type == _MEMSWAP);
4611 /* Calculate new number of threshold */
4613 for (i = 0; i < thresholds->primary->size; i++) {
4614 if (thresholds->primary->entries[i].eventfd != eventfd)
4620 new = thresholds->spare;
4622 /* If no items related to eventfd have been cleared, nothing to do */
4626 /* Set thresholds array to NULL if we don't have thresholds */
4635 /* Copy thresholds and find current threshold */
4636 new->current_threshold = -1;
4637 for (i = 0, j = 0; i < thresholds->primary->size; i++) {
4638 if (thresholds->primary->entries[i].eventfd == eventfd)
4641 new->entries[j] = thresholds->primary->entries[i];
4642 if (new->entries[j].threshold <= usage) {
4644 * new->current_threshold will not be used
4645 * until rcu_assign_pointer(), so it's safe to increment
4648 ++new->current_threshold;
4654 /* Swap primary and spare array */
4655 thresholds->spare = thresholds->primary;
4657 rcu_assign_pointer(thresholds->primary, new);
4659 /* To be sure that nobody uses thresholds */
4662 /* If all events are unregistered, free the spare array */
4664 kfree(thresholds->spare);
4665 thresholds->spare = NULL;
4668 mutex_unlock(&memcg->thresholds_lock);
4671 static void mem_cgroup_usage_unregister_event(struct mem_cgroup *memcg,
4672 struct eventfd_ctx *eventfd)
4674 return __mem_cgroup_usage_unregister_event(memcg, eventfd, _MEM);
4677 static void memsw_cgroup_usage_unregister_event(struct mem_cgroup *memcg,
4678 struct eventfd_ctx *eventfd)
4680 return __mem_cgroup_usage_unregister_event(memcg, eventfd, _MEMSWAP);
4683 static int mem_cgroup_oom_register_event(struct mem_cgroup *memcg,
4684 struct eventfd_ctx *eventfd, const char *args)
4686 struct mem_cgroup_eventfd_list *event;
4688 event = kmalloc(sizeof(*event), GFP_KERNEL);
4692 spin_lock(&memcg_oom_lock);
4694 event->eventfd = eventfd;
4695 list_add(&event->list, &memcg->oom_notify);
4697 /* already in OOM ? */
4698 if (memcg->under_oom)
4699 eventfd_signal(eventfd);
4700 spin_unlock(&memcg_oom_lock);
4705 static void mem_cgroup_oom_unregister_event(struct mem_cgroup *memcg,
4706 struct eventfd_ctx *eventfd)
4708 struct mem_cgroup_eventfd_list *ev, *tmp;
4710 spin_lock(&memcg_oom_lock);
4712 list_for_each_entry_safe(ev, tmp, &memcg->oom_notify, list) {
4713 if (ev->eventfd == eventfd) {
4714 list_del(&ev->list);
4719 spin_unlock(&memcg_oom_lock);
4722 static int mem_cgroup_oom_control_read(struct seq_file *sf, void *v)
4724 struct mem_cgroup *memcg = mem_cgroup_from_seq(sf);
4726 seq_printf(sf, "oom_kill_disable %d\n", READ_ONCE(memcg->oom_kill_disable));
4727 seq_printf(sf, "under_oom %d\n", (bool)memcg->under_oom);
4728 seq_printf(sf, "oom_kill %lu\n",
4729 atomic_long_read(&memcg->memory_events[MEMCG_OOM_KILL]));
4733 static int mem_cgroup_oom_control_write(struct cgroup_subsys_state *css,
4734 struct cftype *cft, u64 val)
4736 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4738 /* cannot set to root cgroup and only 0 and 1 are allowed */
4739 if (mem_cgroup_is_root(memcg) || !((val == 0) || (val == 1)))
4742 WRITE_ONCE(memcg->oom_kill_disable, val);
4744 memcg_oom_recover(memcg);
4749 #ifdef CONFIG_CGROUP_WRITEBACK
4751 #include <trace/events/writeback.h>
4753 static int memcg_wb_domain_init(struct mem_cgroup *memcg, gfp_t gfp)
4755 return wb_domain_init(&memcg->cgwb_domain, gfp);
4758 static void memcg_wb_domain_exit(struct mem_cgroup *memcg)
4760 wb_domain_exit(&memcg->cgwb_domain);
4763 static void memcg_wb_domain_size_changed(struct mem_cgroup *memcg)
4765 wb_domain_size_changed(&memcg->cgwb_domain);
4768 struct wb_domain *mem_cgroup_wb_domain(struct bdi_writeback *wb)
4770 struct mem_cgroup *memcg = mem_cgroup_from_css(wb->memcg_css);
4772 if (!memcg->css.parent)
4775 return &memcg->cgwb_domain;
4779 * mem_cgroup_wb_stats - retrieve writeback related stats from its memcg
4780 * @wb: bdi_writeback in question
4781 * @pfilepages: out parameter for number of file pages
4782 * @pheadroom: out parameter for number of allocatable pages according to memcg
4783 * @pdirty: out parameter for number of dirty pages
4784 * @pwriteback: out parameter for number of pages under writeback
4786 * Determine the numbers of file, headroom, dirty, and writeback pages in
4787 * @wb's memcg. File, dirty and writeback are self-explanatory. Headroom
4788 * is a bit more involved.
4790 * A memcg's headroom is "min(max, high) - used". In the hierarchy, the
4791 * headroom is calculated as the lowest headroom of itself and the
4792 * ancestors. Note that this doesn't consider the actual amount of
4793 * available memory in the system. The caller should further cap
4794 * *@pheadroom accordingly.
4796 void mem_cgroup_wb_stats(struct bdi_writeback *wb, unsigned long *pfilepages,
4797 unsigned long *pheadroom, unsigned long *pdirty,
4798 unsigned long *pwriteback)
4800 struct mem_cgroup *memcg = mem_cgroup_from_css(wb->memcg_css);
4801 struct mem_cgroup *parent;
4803 mem_cgroup_flush_stats(memcg);
4805 *pdirty = memcg_page_state(memcg, NR_FILE_DIRTY);
4806 *pwriteback = memcg_page_state(memcg, NR_WRITEBACK);
4807 *pfilepages = memcg_page_state(memcg, NR_INACTIVE_FILE) +
4808 memcg_page_state(memcg, NR_ACTIVE_FILE);
4810 *pheadroom = PAGE_COUNTER_MAX;
4811 while ((parent = parent_mem_cgroup(memcg))) {
4812 unsigned long ceiling = min(READ_ONCE(memcg->memory.max),
4813 READ_ONCE(memcg->memory.high));
4814 unsigned long used = page_counter_read(&memcg->memory);
4816 *pheadroom = min(*pheadroom, ceiling - min(ceiling, used));
4822 * Foreign dirty flushing
4824 * There's an inherent mismatch between memcg and writeback. The former
4825 * tracks ownership per-page while the latter per-inode. This was a
4826 * deliberate design decision because honoring per-page ownership in the
4827 * writeback path is complicated, may lead to higher CPU and IO overheads
4828 * and deemed unnecessary given that write-sharing an inode across
4829 * different cgroups isn't a common use-case.
4831 * Combined with inode majority-writer ownership switching, this works well
4832 * enough in most cases but there are some pathological cases. For
4833 * example, let's say there are two cgroups A and B which keep writing to
4834 * different but confined parts of the same inode. B owns the inode and
4835 * A's memory is limited far below B's. A's dirty ratio can rise enough to
4836 * trigger balance_dirty_pages() sleeps but B's can be low enough to avoid
4837 * triggering background writeback. A will be slowed down without a way to
4838 * make writeback of the dirty pages happen.
4840 * Conditions like the above can lead to a cgroup getting repeatedly and
4841 * severely throttled after making some progress after each
4842 * dirty_expire_interval while the underlying IO device is almost
4845 * Solving this problem completely requires matching the ownership tracking
4846 * granularities between memcg and writeback in either direction. However,
4847 * the more egregious behaviors can be avoided by simply remembering the
4848 * most recent foreign dirtying events and initiating remote flushes on
4849 * them when local writeback isn't enough to keep the memory clean enough.
4851 * The following two functions implement such mechanism. When a foreign
4852 * page - a page whose memcg and writeback ownerships don't match - is
4853 * dirtied, mem_cgroup_track_foreign_dirty() records the inode owning
4854 * bdi_writeback on the page owning memcg. When balance_dirty_pages()
4855 * decides that the memcg needs to sleep due to high dirty ratio, it calls
4856 * mem_cgroup_flush_foreign() which queues writeback on the recorded
4857 * foreign bdi_writebacks which haven't expired. Both the numbers of
4858 * recorded bdi_writebacks and concurrent in-flight foreign writebacks are
4859 * limited to MEMCG_CGWB_FRN_CNT.
4861 * The mechanism only remembers IDs and doesn't hold any object references.
4862 * As being wrong occasionally doesn't matter, updates and accesses to the
4863 * records are lockless and racy.
4865 void mem_cgroup_track_foreign_dirty_slowpath(struct folio *folio,
4866 struct bdi_writeback *wb)
4868 struct mem_cgroup *memcg = folio_memcg(folio);
4869 struct memcg_cgwb_frn *frn;
4870 u64 now = get_jiffies_64();
4871 u64 oldest_at = now;
4875 trace_track_foreign_dirty(folio, wb);
4878 * Pick the slot to use. If there is already a slot for @wb, keep
4879 * using it. If not replace the oldest one which isn't being
4882 for (i = 0; i < MEMCG_CGWB_FRN_CNT; i++) {
4883 frn = &memcg->cgwb_frn[i];
4884 if (frn->bdi_id == wb->bdi->id &&
4885 frn->memcg_id == wb->memcg_css->id)
4887 if (time_before64(frn->at, oldest_at) &&
4888 atomic_read(&frn->done.cnt) == 1) {
4890 oldest_at = frn->at;
4894 if (i < MEMCG_CGWB_FRN_CNT) {
4896 * Re-using an existing one. Update timestamp lazily to
4897 * avoid making the cacheline hot. We want them to be
4898 * reasonably up-to-date and significantly shorter than
4899 * dirty_expire_interval as that's what expires the record.
4900 * Use the shorter of 1s and dirty_expire_interval / 8.
4902 unsigned long update_intv =
4903 min_t(unsigned long, HZ,
4904 msecs_to_jiffies(dirty_expire_interval * 10) / 8);
4906 if (time_before64(frn->at, now - update_intv))
4908 } else if (oldest >= 0) {
4909 /* replace the oldest free one */
4910 frn = &memcg->cgwb_frn[oldest];
4911 frn->bdi_id = wb->bdi->id;
4912 frn->memcg_id = wb->memcg_css->id;
4917 /* issue foreign writeback flushes for recorded foreign dirtying events */
4918 void mem_cgroup_flush_foreign(struct bdi_writeback *wb)
4920 struct mem_cgroup *memcg = mem_cgroup_from_css(wb->memcg_css);
4921 unsigned long intv = msecs_to_jiffies(dirty_expire_interval * 10);
4922 u64 now = jiffies_64;
4925 for (i = 0; i < MEMCG_CGWB_FRN_CNT; i++) {
4926 struct memcg_cgwb_frn *frn = &memcg->cgwb_frn[i];
4929 * If the record is older than dirty_expire_interval,
4930 * writeback on it has already started. No need to kick it
4931 * off again. Also, don't start a new one if there's
4932 * already one in flight.
4934 if (time_after64(frn->at, now - intv) &&
4935 atomic_read(&frn->done.cnt) == 1) {
4937 trace_flush_foreign(wb, frn->bdi_id, frn->memcg_id);
4938 cgroup_writeback_by_id(frn->bdi_id, frn->memcg_id,
4939 WB_REASON_FOREIGN_FLUSH,
4945 #else /* CONFIG_CGROUP_WRITEBACK */
4947 static int memcg_wb_domain_init(struct mem_cgroup *memcg, gfp_t gfp)
4952 static void memcg_wb_domain_exit(struct mem_cgroup *memcg)
4956 static void memcg_wb_domain_size_changed(struct mem_cgroup *memcg)
4960 #endif /* CONFIG_CGROUP_WRITEBACK */
4963 * DO NOT USE IN NEW FILES.
4965 * "cgroup.event_control" implementation.
4967 * This is way over-engineered. It tries to support fully configurable
4968 * events for each user. Such level of flexibility is completely
4969 * unnecessary especially in the light of the planned unified hierarchy.
4971 * Please deprecate this and replace with something simpler if at all
4976 * Unregister event and free resources.
4978 * Gets called from workqueue.
4980 static void memcg_event_remove(struct work_struct *work)
4982 struct mem_cgroup_event *event =
4983 container_of(work, struct mem_cgroup_event, remove);
4984 struct mem_cgroup *memcg = event->memcg;
4986 remove_wait_queue(event->wqh, &event->wait);
4988 event->unregister_event(memcg, event->eventfd);
4990 /* Notify userspace the event is going away. */
4991 eventfd_signal(event->eventfd);
4993 eventfd_ctx_put(event->eventfd);
4995 css_put(&memcg->css);
4999 * Gets called on EPOLLHUP on eventfd when user closes it.
5001 * Called with wqh->lock held and interrupts disabled.
5003 static int memcg_event_wake(wait_queue_entry_t *wait, unsigned mode,
5004 int sync, void *key)
5006 struct mem_cgroup_event *event =
5007 container_of(wait, struct mem_cgroup_event, wait);
5008 struct mem_cgroup *memcg = event->memcg;
5009 __poll_t flags = key_to_poll(key);
5011 if (flags & EPOLLHUP) {
5013 * If the event has been detached at cgroup removal, we
5014 * can simply return knowing the other side will cleanup
5017 * We can't race against event freeing since the other
5018 * side will require wqh->lock via remove_wait_queue(),
5021 spin_lock(&memcg->event_list_lock);
5022 if (!list_empty(&event->list)) {
5023 list_del_init(&event->list);
5025 * We are in atomic context, but cgroup_event_remove()
5026 * may sleep, so we have to call it in workqueue.
5028 schedule_work(&event->remove);
5030 spin_unlock(&memcg->event_list_lock);
5036 static void memcg_event_ptable_queue_proc(struct file *file,
5037 wait_queue_head_t *wqh, poll_table *pt)
5039 struct mem_cgroup_event *event =
5040 container_of(pt, struct mem_cgroup_event, pt);
5043 add_wait_queue(wqh, &event->wait);
5047 * DO NOT USE IN NEW FILES.
5049 * Parse input and register new cgroup event handler.
5051 * Input must be in format '<event_fd> <control_fd> <args>'.
5052 * Interpretation of args is defined by control file implementation.
5054 static ssize_t memcg_write_event_control(struct kernfs_open_file *of,
5055 char *buf, size_t nbytes, loff_t off)
5057 struct cgroup_subsys_state *css = of_css(of);
5058 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5059 struct mem_cgroup_event *event;
5060 struct cgroup_subsys_state *cfile_css;
5061 unsigned int efd, cfd;
5064 struct dentry *cdentry;
5069 if (IS_ENABLED(CONFIG_PREEMPT_RT))
5072 buf = strstrip(buf);
5074 efd = simple_strtoul(buf, &endp, 10);
5079 cfd = simple_strtoul(buf, &endp, 10);
5080 if ((*endp != ' ') && (*endp != '\0'))
5084 event = kzalloc(sizeof(*event), GFP_KERNEL);
5088 event->memcg = memcg;
5089 INIT_LIST_HEAD(&event->list);
5090 init_poll_funcptr(&event->pt, memcg_event_ptable_queue_proc);
5091 init_waitqueue_func_entry(&event->wait, memcg_event_wake);
5092 INIT_WORK(&event->remove, memcg_event_remove);
5100 event->eventfd = eventfd_ctx_fileget(efile.file);
5101 if (IS_ERR(event->eventfd)) {
5102 ret = PTR_ERR(event->eventfd);
5109 goto out_put_eventfd;
5112 /* the process need read permission on control file */
5113 /* AV: shouldn't we check that it's been opened for read instead? */
5114 ret = file_permission(cfile.file, MAY_READ);
5119 * The control file must be a regular cgroup1 file. As a regular cgroup
5120 * file can't be renamed, it's safe to access its name afterwards.
5122 cdentry = cfile.file->f_path.dentry;
5123 if (cdentry->d_sb->s_type != &cgroup_fs_type || !d_is_reg(cdentry)) {
5129 * Determine the event callbacks and set them in @event. This used
5130 * to be done via struct cftype but cgroup core no longer knows
5131 * about these events. The following is crude but the whole thing
5132 * is for compatibility anyway.
5134 * DO NOT ADD NEW FILES.
5136 name = cdentry->d_name.name;
5138 if (!strcmp(name, "memory.usage_in_bytes")) {
5139 event->register_event = mem_cgroup_usage_register_event;
5140 event->unregister_event = mem_cgroup_usage_unregister_event;
5141 } else if (!strcmp(name, "memory.oom_control")) {
5142 event->register_event = mem_cgroup_oom_register_event;
5143 event->unregister_event = mem_cgroup_oom_unregister_event;
5144 } else if (!strcmp(name, "memory.pressure_level")) {
5145 event->register_event = vmpressure_register_event;
5146 event->unregister_event = vmpressure_unregister_event;
5147 } else if (!strcmp(name, "memory.memsw.usage_in_bytes")) {
5148 event->register_event = memsw_cgroup_usage_register_event;
5149 event->unregister_event = memsw_cgroup_usage_unregister_event;
5156 * Verify @cfile should belong to @css. Also, remaining events are
5157 * automatically removed on cgroup destruction but the removal is
5158 * asynchronous, so take an extra ref on @css.
5160 cfile_css = css_tryget_online_from_dir(cdentry->d_parent,
5161 &memory_cgrp_subsys);
5163 if (IS_ERR(cfile_css))
5165 if (cfile_css != css) {
5170 ret = event->register_event(memcg, event->eventfd, buf);
5174 vfs_poll(efile.file, &event->pt);
5176 spin_lock_irq(&memcg->event_list_lock);
5177 list_add(&event->list, &memcg->event_list);
5178 spin_unlock_irq(&memcg->event_list_lock);
5190 eventfd_ctx_put(event->eventfd);
5199 #if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_SLUB_DEBUG)
5200 static int mem_cgroup_slab_show(struct seq_file *m, void *p)
5204 * Please, take a look at tools/cgroup/memcg_slabinfo.py .
5210 static int memory_stat_show(struct seq_file *m, void *v);
5212 static struct cftype mem_cgroup_legacy_files[] = {
5214 .name = "usage_in_bytes",
5215 .private = MEMFILE_PRIVATE(_MEM, RES_USAGE),
5216 .read_u64 = mem_cgroup_read_u64,
5219 .name = "max_usage_in_bytes",
5220 .private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE),
5221 .write = mem_cgroup_reset,
5222 .read_u64 = mem_cgroup_read_u64,
5225 .name = "limit_in_bytes",
5226 .private = MEMFILE_PRIVATE(_MEM, RES_LIMIT),
5227 .write = mem_cgroup_write,
5228 .read_u64 = mem_cgroup_read_u64,
5231 .name = "soft_limit_in_bytes",
5232 .private = MEMFILE_PRIVATE(_MEM, RES_SOFT_LIMIT),
5233 .write = mem_cgroup_write,
5234 .read_u64 = mem_cgroup_read_u64,
5238 .private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT),
5239 .write = mem_cgroup_reset,
5240 .read_u64 = mem_cgroup_read_u64,
5244 .seq_show = memory_stat_show,
5247 .name = "force_empty",
5248 .write = mem_cgroup_force_empty_write,
5251 .name = "use_hierarchy",
5252 .write_u64 = mem_cgroup_hierarchy_write,
5253 .read_u64 = mem_cgroup_hierarchy_read,
5256 .name = "cgroup.event_control", /* XXX: for compat */
5257 .write = memcg_write_event_control,
5258 .flags = CFTYPE_NO_PREFIX | CFTYPE_WORLD_WRITABLE,
5261 .name = "swappiness",
5262 .read_u64 = mem_cgroup_swappiness_read,
5263 .write_u64 = mem_cgroup_swappiness_write,
5266 .name = "move_charge_at_immigrate",
5267 .read_u64 = mem_cgroup_move_charge_read,
5268 .write_u64 = mem_cgroup_move_charge_write,
5271 .name = "oom_control",
5272 .seq_show = mem_cgroup_oom_control_read,
5273 .write_u64 = mem_cgroup_oom_control_write,
5276 .name = "pressure_level",
5277 .seq_show = mem_cgroup_dummy_seq_show,
5281 .name = "numa_stat",
5282 .seq_show = memcg_numa_stat_show,
5286 .name = "kmem.limit_in_bytes",
5287 .private = MEMFILE_PRIVATE(_KMEM, RES_LIMIT),
5288 .write = mem_cgroup_write,
5289 .read_u64 = mem_cgroup_read_u64,
5292 .name = "kmem.usage_in_bytes",
5293 .private = MEMFILE_PRIVATE(_KMEM, RES_USAGE),
5294 .read_u64 = mem_cgroup_read_u64,
5297 .name = "kmem.failcnt",
5298 .private = MEMFILE_PRIVATE(_KMEM, RES_FAILCNT),
5299 .write = mem_cgroup_reset,
5300 .read_u64 = mem_cgroup_read_u64,
5303 .name = "kmem.max_usage_in_bytes",
5304 .private = MEMFILE_PRIVATE(_KMEM, RES_MAX_USAGE),
5305 .write = mem_cgroup_reset,
5306 .read_u64 = mem_cgroup_read_u64,
5308 #if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_SLUB_DEBUG)
5310 .name = "kmem.slabinfo",
5311 .seq_show = mem_cgroup_slab_show,
5315 .name = "kmem.tcp.limit_in_bytes",
5316 .private = MEMFILE_PRIVATE(_TCP, RES_LIMIT),
5317 .write = mem_cgroup_write,
5318 .read_u64 = mem_cgroup_read_u64,
5321 .name = "kmem.tcp.usage_in_bytes",
5322 .private = MEMFILE_PRIVATE(_TCP, RES_USAGE),
5323 .read_u64 = mem_cgroup_read_u64,
5326 .name = "kmem.tcp.failcnt",
5327 .private = MEMFILE_PRIVATE(_TCP, RES_FAILCNT),
5328 .write = mem_cgroup_reset,
5329 .read_u64 = mem_cgroup_read_u64,
5332 .name = "kmem.tcp.max_usage_in_bytes",
5333 .private = MEMFILE_PRIVATE(_TCP, RES_MAX_USAGE),
5334 .write = mem_cgroup_reset,
5335 .read_u64 = mem_cgroup_read_u64,
5337 { }, /* terminate */
5341 * Private memory cgroup IDR
5343 * Swap-out records and page cache shadow entries need to store memcg
5344 * references in constrained space, so we maintain an ID space that is
5345 * limited to 16 bit (MEM_CGROUP_ID_MAX), limiting the total number of
5346 * memory-controlled cgroups to 64k.
5348 * However, there usually are many references to the offline CSS after
5349 * the cgroup has been destroyed, such as page cache or reclaimable
5350 * slab objects, that don't need to hang on to the ID. We want to keep
5351 * those dead CSS from occupying IDs, or we might quickly exhaust the
5352 * relatively small ID space and prevent the creation of new cgroups
5353 * even when there are much fewer than 64k cgroups - possibly none.
5355 * Maintain a private 16-bit ID space for memcg, and allow the ID to
5356 * be freed and recycled when it's no longer needed, which is usually
5357 * when the CSS is offlined.
5359 * The only exception to that are records of swapped out tmpfs/shmem
5360 * pages that need to be attributed to live ancestors on swapin. But
5361 * those references are manageable from userspace.
5364 #define MEM_CGROUP_ID_MAX ((1UL << MEM_CGROUP_ID_SHIFT) - 1)
5365 static DEFINE_IDR(mem_cgroup_idr);
5367 static void mem_cgroup_id_remove(struct mem_cgroup *memcg)
5369 if (memcg->id.id > 0) {
5370 idr_remove(&mem_cgroup_idr, memcg->id.id);
5375 static void __maybe_unused mem_cgroup_id_get_many(struct mem_cgroup *memcg,
5378 refcount_add(n, &memcg->id.ref);
5381 static void mem_cgroup_id_put_many(struct mem_cgroup *memcg, unsigned int n)
5383 if (refcount_sub_and_test(n, &memcg->id.ref)) {
5384 mem_cgroup_id_remove(memcg);
5386 /* Memcg ID pins CSS */
5387 css_put(&memcg->css);
5391 static inline void mem_cgroup_id_put(struct mem_cgroup *memcg)
5393 mem_cgroup_id_put_many(memcg, 1);
5397 * mem_cgroup_from_id - look up a memcg from a memcg id
5398 * @id: the memcg id to look up
5400 * Caller must hold rcu_read_lock().
5402 struct mem_cgroup *mem_cgroup_from_id(unsigned short id)
5404 WARN_ON_ONCE(!rcu_read_lock_held());
5405 return idr_find(&mem_cgroup_idr, id);
5408 #ifdef CONFIG_SHRINKER_DEBUG
5409 struct mem_cgroup *mem_cgroup_get_from_ino(unsigned long ino)
5411 struct cgroup *cgrp;
5412 struct cgroup_subsys_state *css;
5413 struct mem_cgroup *memcg;
5415 cgrp = cgroup_get_from_id(ino);
5417 return ERR_CAST(cgrp);
5419 css = cgroup_get_e_css(cgrp, &memory_cgrp_subsys);
5421 memcg = container_of(css, struct mem_cgroup, css);
5423 memcg = ERR_PTR(-ENOENT);
5431 static int alloc_mem_cgroup_per_node_info(struct mem_cgroup *memcg, int node)
5433 struct mem_cgroup_per_node *pn;
5435 pn = kzalloc_node(sizeof(*pn), GFP_KERNEL, node);
5439 pn->lruvec_stats_percpu = alloc_percpu_gfp(struct lruvec_stats_percpu,
5440 GFP_KERNEL_ACCOUNT);
5441 if (!pn->lruvec_stats_percpu) {
5446 lruvec_init(&pn->lruvec);
5449 memcg->nodeinfo[node] = pn;
5453 static void free_mem_cgroup_per_node_info(struct mem_cgroup *memcg, int node)
5455 struct mem_cgroup_per_node *pn = memcg->nodeinfo[node];
5460 free_percpu(pn->lruvec_stats_percpu);
5464 static void __mem_cgroup_free(struct mem_cgroup *memcg)
5468 if (memcg->orig_objcg)
5469 obj_cgroup_put(memcg->orig_objcg);
5472 free_mem_cgroup_per_node_info(memcg, node);
5473 kfree(memcg->vmstats);
5474 free_percpu(memcg->vmstats_percpu);
5478 static void mem_cgroup_free(struct mem_cgroup *memcg)
5480 lru_gen_exit_memcg(memcg);
5481 memcg_wb_domain_exit(memcg);
5482 __mem_cgroup_free(memcg);
5485 static struct mem_cgroup *mem_cgroup_alloc(struct mem_cgroup *parent)
5487 struct memcg_vmstats_percpu *statc, *pstatc;
5488 struct mem_cgroup *memcg;
5490 int __maybe_unused i;
5491 long error = -ENOMEM;
5493 memcg = kzalloc(struct_size(memcg, nodeinfo, nr_node_ids), GFP_KERNEL);
5495 return ERR_PTR(error);
5497 memcg->id.id = idr_alloc(&mem_cgroup_idr, NULL,
5498 1, MEM_CGROUP_ID_MAX + 1, GFP_KERNEL);
5499 if (memcg->id.id < 0) {
5500 error = memcg->id.id;
5504 memcg->vmstats = kzalloc(sizeof(struct memcg_vmstats), GFP_KERNEL);
5505 if (!memcg->vmstats)
5508 memcg->vmstats_percpu = alloc_percpu_gfp(struct memcg_vmstats_percpu,
5509 GFP_KERNEL_ACCOUNT);
5510 if (!memcg->vmstats_percpu)
5513 for_each_possible_cpu(cpu) {
5515 pstatc = per_cpu_ptr(parent->vmstats_percpu, cpu);
5516 statc = per_cpu_ptr(memcg->vmstats_percpu, cpu);
5517 statc->parent = parent ? pstatc : NULL;
5518 statc->vmstats = memcg->vmstats;
5522 if (alloc_mem_cgroup_per_node_info(memcg, node))
5525 if (memcg_wb_domain_init(memcg, GFP_KERNEL))
5528 INIT_WORK(&memcg->high_work, high_work_func);
5529 INIT_LIST_HEAD(&memcg->oom_notify);
5530 mutex_init(&memcg->thresholds_lock);
5531 spin_lock_init(&memcg->move_lock);
5532 vmpressure_init(&memcg->vmpressure);
5533 INIT_LIST_HEAD(&memcg->event_list);
5534 spin_lock_init(&memcg->event_list_lock);
5535 memcg->socket_pressure = jiffies;
5536 #ifdef CONFIG_MEMCG_KMEM
5537 memcg->kmemcg_id = -1;
5538 INIT_LIST_HEAD(&memcg->objcg_list);
5540 #ifdef CONFIG_CGROUP_WRITEBACK
5541 INIT_LIST_HEAD(&memcg->cgwb_list);
5542 for (i = 0; i < MEMCG_CGWB_FRN_CNT; i++)
5543 memcg->cgwb_frn[i].done =
5544 __WB_COMPLETION_INIT(&memcg_cgwb_frn_waitq);
5546 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
5547 spin_lock_init(&memcg->deferred_split_queue.split_queue_lock);
5548 INIT_LIST_HEAD(&memcg->deferred_split_queue.split_queue);
5549 memcg->deferred_split_queue.split_queue_len = 0;
5551 lru_gen_init_memcg(memcg);
5554 mem_cgroup_id_remove(memcg);
5555 __mem_cgroup_free(memcg);
5556 return ERR_PTR(error);
5559 static struct cgroup_subsys_state * __ref
5560 mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
5562 struct mem_cgroup *parent = mem_cgroup_from_css(parent_css);
5563 struct mem_cgroup *memcg, *old_memcg;
5565 old_memcg = set_active_memcg(parent);
5566 memcg = mem_cgroup_alloc(parent);
5567 set_active_memcg(old_memcg);
5569 return ERR_CAST(memcg);
5571 page_counter_set_high(&memcg->memory, PAGE_COUNTER_MAX);
5572 WRITE_ONCE(memcg->soft_limit, PAGE_COUNTER_MAX);
5573 #if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_ZSWAP)
5574 memcg->zswap_max = PAGE_COUNTER_MAX;
5575 WRITE_ONCE(memcg->zswap_writeback,
5576 !parent || READ_ONCE(parent->zswap_writeback));
5578 page_counter_set_high(&memcg->swap, PAGE_COUNTER_MAX);
5580 WRITE_ONCE(memcg->swappiness, mem_cgroup_swappiness(parent));
5581 WRITE_ONCE(memcg->oom_kill_disable, READ_ONCE(parent->oom_kill_disable));
5583 page_counter_init(&memcg->memory, &parent->memory);
5584 page_counter_init(&memcg->swap, &parent->swap);
5585 page_counter_init(&memcg->kmem, &parent->kmem);
5586 page_counter_init(&memcg->tcpmem, &parent->tcpmem);
5588 init_memcg_events();
5589 page_counter_init(&memcg->memory, NULL);
5590 page_counter_init(&memcg->swap, NULL);
5591 page_counter_init(&memcg->kmem, NULL);
5592 page_counter_init(&memcg->tcpmem, NULL);
5594 root_mem_cgroup = memcg;
5598 if (cgroup_subsys_on_dfl(memory_cgrp_subsys) && !cgroup_memory_nosocket)
5599 static_branch_inc(&memcg_sockets_enabled_key);
5601 #if defined(CONFIG_MEMCG_KMEM)
5602 if (!cgroup_memory_nobpf)
5603 static_branch_inc(&memcg_bpf_enabled_key);
5609 static int mem_cgroup_css_online(struct cgroup_subsys_state *css)
5611 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5613 if (memcg_online_kmem(memcg))
5617 * A memcg must be visible for expand_shrinker_info()
5618 * by the time the maps are allocated. So, we allocate maps
5619 * here, when for_each_mem_cgroup() can't skip it.
5621 if (alloc_shrinker_info(memcg))
5624 if (unlikely(mem_cgroup_is_root(memcg)))
5625 queue_delayed_work(system_unbound_wq, &stats_flush_dwork,
5627 lru_gen_online_memcg(memcg);
5629 /* Online state pins memcg ID, memcg ID pins CSS */
5630 refcount_set(&memcg->id.ref, 1);
5634 * Ensure mem_cgroup_from_id() works once we're fully online.
5636 * We could do this earlier and require callers to filter with
5637 * css_tryget_online(). But right now there are no users that
5638 * need earlier access, and the workingset code relies on the
5639 * cgroup tree linkage (mem_cgroup_get_nr_swap_pages()). So
5640 * publish it here at the end of onlining. This matches the
5641 * regular ID destruction during offlining.
5643 idr_replace(&mem_cgroup_idr, memcg, memcg->id.id);
5647 memcg_offline_kmem(memcg);
5649 mem_cgroup_id_remove(memcg);
5653 static void mem_cgroup_css_offline(struct cgroup_subsys_state *css)
5655 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5656 struct mem_cgroup_event *event, *tmp;
5659 * Unregister events and notify userspace.
5660 * Notify userspace about cgroup removing only after rmdir of cgroup
5661 * directory to avoid race between userspace and kernelspace.
5663 spin_lock_irq(&memcg->event_list_lock);
5664 list_for_each_entry_safe(event, tmp, &memcg->event_list, list) {
5665 list_del_init(&event->list);
5666 schedule_work(&event->remove);
5668 spin_unlock_irq(&memcg->event_list_lock);
5670 page_counter_set_min(&memcg->memory, 0);
5671 page_counter_set_low(&memcg->memory, 0);
5673 zswap_memcg_offline_cleanup(memcg);
5675 memcg_offline_kmem(memcg);
5676 reparent_shrinker_deferred(memcg);
5677 wb_memcg_offline(memcg);
5678 lru_gen_offline_memcg(memcg);
5680 drain_all_stock(memcg);
5682 mem_cgroup_id_put(memcg);
5685 static void mem_cgroup_css_released(struct cgroup_subsys_state *css)
5687 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5689 invalidate_reclaim_iterators(memcg);
5690 lru_gen_release_memcg(memcg);
5693 static void mem_cgroup_css_free(struct cgroup_subsys_state *css)
5695 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5696 int __maybe_unused i;
5698 #ifdef CONFIG_CGROUP_WRITEBACK
5699 for (i = 0; i < MEMCG_CGWB_FRN_CNT; i++)
5700 wb_wait_for_completion(&memcg->cgwb_frn[i].done);
5702 if (cgroup_subsys_on_dfl(memory_cgrp_subsys) && !cgroup_memory_nosocket)
5703 static_branch_dec(&memcg_sockets_enabled_key);
5705 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && memcg->tcpmem_active)
5706 static_branch_dec(&memcg_sockets_enabled_key);
5708 #if defined(CONFIG_MEMCG_KMEM)
5709 if (!cgroup_memory_nobpf)
5710 static_branch_dec(&memcg_bpf_enabled_key);
5713 vmpressure_cleanup(&memcg->vmpressure);
5714 cancel_work_sync(&memcg->high_work);
5715 mem_cgroup_remove_from_trees(memcg);
5716 free_shrinker_info(memcg);
5717 mem_cgroup_free(memcg);
5721 * mem_cgroup_css_reset - reset the states of a mem_cgroup
5722 * @css: the target css
5724 * Reset the states of the mem_cgroup associated with @css. This is
5725 * invoked when the userland requests disabling on the default hierarchy
5726 * but the memcg is pinned through dependency. The memcg should stop
5727 * applying policies and should revert to the vanilla state as it may be
5728 * made visible again.
5730 * The current implementation only resets the essential configurations.
5731 * This needs to be expanded to cover all the visible parts.
5733 static void mem_cgroup_css_reset(struct cgroup_subsys_state *css)
5735 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5737 page_counter_set_max(&memcg->memory, PAGE_COUNTER_MAX);
5738 page_counter_set_max(&memcg->swap, PAGE_COUNTER_MAX);
5739 page_counter_set_max(&memcg->kmem, PAGE_COUNTER_MAX);
5740 page_counter_set_max(&memcg->tcpmem, PAGE_COUNTER_MAX);
5741 page_counter_set_min(&memcg->memory, 0);
5742 page_counter_set_low(&memcg->memory, 0);
5743 page_counter_set_high(&memcg->memory, PAGE_COUNTER_MAX);
5744 WRITE_ONCE(memcg->soft_limit, PAGE_COUNTER_MAX);
5745 page_counter_set_high(&memcg->swap, PAGE_COUNTER_MAX);
5746 memcg_wb_domain_size_changed(memcg);
5749 static void mem_cgroup_css_rstat_flush(struct cgroup_subsys_state *css, int cpu)
5751 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5752 struct mem_cgroup *parent = parent_mem_cgroup(memcg);
5753 struct memcg_vmstats_percpu *statc;
5754 long delta, delta_cpu, v;
5757 statc = per_cpu_ptr(memcg->vmstats_percpu, cpu);
5759 for (i = 0; i < MEMCG_NR_STAT; i++) {
5761 * Collect the aggregated propagation counts of groups
5762 * below us. We're in a per-cpu loop here and this is
5763 * a global counter, so the first cycle will get them.
5765 delta = memcg->vmstats->state_pending[i];
5767 memcg->vmstats->state_pending[i] = 0;
5769 /* Add CPU changes on this level since the last flush */
5771 v = READ_ONCE(statc->state[i]);
5772 if (v != statc->state_prev[i]) {
5773 delta_cpu = v - statc->state_prev[i];
5775 statc->state_prev[i] = v;
5778 /* Aggregate counts on this level and propagate upwards */
5780 memcg->vmstats->state_local[i] += delta_cpu;
5783 memcg->vmstats->state[i] += delta;
5785 parent->vmstats->state_pending[i] += delta;
5789 for (i = 0; i < NR_MEMCG_EVENTS; i++) {
5790 delta = memcg->vmstats->events_pending[i];
5792 memcg->vmstats->events_pending[i] = 0;
5795 v = READ_ONCE(statc->events[i]);
5796 if (v != statc->events_prev[i]) {
5797 delta_cpu = v - statc->events_prev[i];
5799 statc->events_prev[i] = v;
5803 memcg->vmstats->events_local[i] += delta_cpu;
5806 memcg->vmstats->events[i] += delta;
5808 parent->vmstats->events_pending[i] += delta;
5812 for_each_node_state(nid, N_MEMORY) {
5813 struct mem_cgroup_per_node *pn = memcg->nodeinfo[nid];
5814 struct mem_cgroup_per_node *ppn = NULL;
5815 struct lruvec_stats_percpu *lstatc;
5818 ppn = parent->nodeinfo[nid];
5820 lstatc = per_cpu_ptr(pn->lruvec_stats_percpu, cpu);
5822 for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) {
5823 delta = pn->lruvec_stats.state_pending[i];
5825 pn->lruvec_stats.state_pending[i] = 0;
5828 v = READ_ONCE(lstatc->state[i]);
5829 if (v != lstatc->state_prev[i]) {
5830 delta_cpu = v - lstatc->state_prev[i];
5832 lstatc->state_prev[i] = v;
5836 pn->lruvec_stats.state_local[i] += delta_cpu;
5839 pn->lruvec_stats.state[i] += delta;
5841 ppn->lruvec_stats.state_pending[i] += delta;
5845 statc->stats_updates = 0;
5846 /* We are in a per-cpu loop here, only do the atomic write once */
5847 if (atomic64_read(&memcg->vmstats->stats_updates))
5848 atomic64_set(&memcg->vmstats->stats_updates, 0);
5852 /* Handlers for move charge at task migration. */
5853 static int mem_cgroup_do_precharge(unsigned long count)
5857 /* Try a single bulk charge without reclaim first, kswapd may wake */
5858 ret = try_charge(mc.to, GFP_KERNEL & ~__GFP_DIRECT_RECLAIM, count);
5860 mc.precharge += count;
5864 /* Try charges one by one with reclaim, but do not retry */
5866 ret = try_charge(mc.to, GFP_KERNEL | __GFP_NORETRY, 1);
5880 enum mc_target_type {
5887 static struct page *mc_handle_present_pte(struct vm_area_struct *vma,
5888 unsigned long addr, pte_t ptent)
5890 struct page *page = vm_normal_page(vma, addr, ptent);
5894 if (PageAnon(page)) {
5895 if (!(mc.flags & MOVE_ANON))
5898 if (!(mc.flags & MOVE_FILE))
5906 #if defined(CONFIG_SWAP) || defined(CONFIG_DEVICE_PRIVATE)
5907 static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
5908 pte_t ptent, swp_entry_t *entry)
5910 struct page *page = NULL;
5911 swp_entry_t ent = pte_to_swp_entry(ptent);
5913 if (!(mc.flags & MOVE_ANON))
5917 * Handle device private pages that are not accessible by the CPU, but
5918 * stored as special swap entries in the page table.
5920 if (is_device_private_entry(ent)) {
5921 page = pfn_swap_entry_to_page(ent);
5922 if (!get_page_unless_zero(page))
5927 if (non_swap_entry(ent))
5931 * Because swap_cache_get_folio() updates some statistics counter,
5932 * we call find_get_page() with swapper_space directly.
5934 page = find_get_page(swap_address_space(ent), swp_offset(ent));
5935 entry->val = ent.val;
5940 static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
5941 pte_t ptent, swp_entry_t *entry)
5947 static struct page *mc_handle_file_pte(struct vm_area_struct *vma,
5948 unsigned long addr, pte_t ptent)
5950 unsigned long index;
5951 struct folio *folio;
5953 if (!vma->vm_file) /* anonymous vma */
5955 if (!(mc.flags & MOVE_FILE))
5958 /* folio is moved even if it's not RSS of this task(page-faulted). */
5959 /* shmem/tmpfs may report page out on swap: account for that too. */
5960 index = linear_page_index(vma, addr);
5961 folio = filemap_get_incore_folio(vma->vm_file->f_mapping, index);
5964 return folio_file_page(folio, index);
5968 * mem_cgroup_move_account - move account of the page
5970 * @compound: charge the page as compound or small page
5971 * @from: mem_cgroup which the page is moved from.
5972 * @to: mem_cgroup which the page is moved to. @from != @to.
5974 * The page must be locked and not on the LRU.
5976 * This function doesn't do "charge" to new cgroup and doesn't do "uncharge"
5979 static int mem_cgroup_move_account(struct page *page,
5981 struct mem_cgroup *from,
5982 struct mem_cgroup *to)
5984 struct folio *folio = page_folio(page);
5985 struct lruvec *from_vec, *to_vec;
5986 struct pglist_data *pgdat;
5987 unsigned int nr_pages = compound ? folio_nr_pages(folio) : 1;
5990 VM_BUG_ON(from == to);
5991 VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio);
5992 VM_BUG_ON_FOLIO(folio_test_lru(folio), folio);
5993 VM_BUG_ON(compound && !folio_test_large(folio));
5996 if (folio_memcg(folio) != from)
5999 pgdat = folio_pgdat(folio);
6000 from_vec = mem_cgroup_lruvec(from, pgdat);
6001 to_vec = mem_cgroup_lruvec(to, pgdat);
6003 folio_memcg_lock(folio);
6005 if (folio_test_anon(folio)) {
6006 if (folio_mapped(folio)) {
6007 __mod_lruvec_state(from_vec, NR_ANON_MAPPED, -nr_pages);
6008 __mod_lruvec_state(to_vec, NR_ANON_MAPPED, nr_pages);
6009 if (folio_test_pmd_mappable(folio)) {
6010 __mod_lruvec_state(from_vec, NR_ANON_THPS,
6012 __mod_lruvec_state(to_vec, NR_ANON_THPS,
6017 __mod_lruvec_state(from_vec, NR_FILE_PAGES, -nr_pages);
6018 __mod_lruvec_state(to_vec, NR_FILE_PAGES, nr_pages);
6020 if (folio_test_swapbacked(folio)) {
6021 __mod_lruvec_state(from_vec, NR_SHMEM, -nr_pages);
6022 __mod_lruvec_state(to_vec, NR_SHMEM, nr_pages);
6025 if (folio_mapped(folio)) {
6026 __mod_lruvec_state(from_vec, NR_FILE_MAPPED, -nr_pages);
6027 __mod_lruvec_state(to_vec, NR_FILE_MAPPED, nr_pages);
6030 if (folio_test_dirty(folio)) {
6031 struct address_space *mapping = folio_mapping(folio);
6033 if (mapping_can_writeback(mapping)) {
6034 __mod_lruvec_state(from_vec, NR_FILE_DIRTY,
6036 __mod_lruvec_state(to_vec, NR_FILE_DIRTY,
6043 if (folio_test_swapcache(folio)) {
6044 __mod_lruvec_state(from_vec, NR_SWAPCACHE, -nr_pages);
6045 __mod_lruvec_state(to_vec, NR_SWAPCACHE, nr_pages);
6048 if (folio_test_writeback(folio)) {
6049 __mod_lruvec_state(from_vec, NR_WRITEBACK, -nr_pages);
6050 __mod_lruvec_state(to_vec, NR_WRITEBACK, nr_pages);
6054 * All state has been migrated, let's switch to the new memcg.
6056 * It is safe to change page's memcg here because the page
6057 * is referenced, charged, isolated, and locked: we can't race
6058 * with (un)charging, migration, LRU putback, or anything else
6059 * that would rely on a stable page's memory cgroup.
6061 * Note that folio_memcg_lock is a memcg lock, not a page lock,
6062 * to save space. As soon as we switch page's memory cgroup to a
6063 * new memcg that isn't locked, the above state can change
6064 * concurrently again. Make sure we're truly done with it.
6069 css_put(&from->css);
6071 folio->memcg_data = (unsigned long)to;
6073 __folio_memcg_unlock(from);
6076 nid = folio_nid(folio);
6078 local_irq_disable();
6079 mem_cgroup_charge_statistics(to, nr_pages);
6080 memcg_check_events(to, nid);
6081 mem_cgroup_charge_statistics(from, -nr_pages);
6082 memcg_check_events(from, nid);
6089 * get_mctgt_type - get target type of moving charge
6090 * @vma: the vma the pte to be checked belongs
6091 * @addr: the address corresponding to the pte to be checked
6092 * @ptent: the pte to be checked
6093 * @target: the pointer the target page or swap ent will be stored(can be NULL)
6095 * Context: Called with pte lock held.
6097 * * MC_TARGET_NONE - If the pte is not a target for move charge.
6098 * * MC_TARGET_PAGE - If the page corresponding to this pte is a target for
6099 * move charge. If @target is not NULL, the page is stored in target->page
6100 * with extra refcnt taken (Caller should release it).
6101 * * MC_TARGET_SWAP - If the swap entry corresponding to this pte is a
6102 * target for charge migration. If @target is not NULL, the entry is
6103 * stored in target->ent.
6104 * * MC_TARGET_DEVICE - Like MC_TARGET_PAGE but page is device memory and
6105 * thus not on the lru. For now such page is charged like a regular page
6106 * would be as it is just special memory taking the place of a regular page.
6107 * See Documentations/vm/hmm.txt and include/linux/hmm.h
6109 static enum mc_target_type get_mctgt_type(struct vm_area_struct *vma,
6110 unsigned long addr, pte_t ptent, union mc_target *target)
6112 struct page *page = NULL;
6113 enum mc_target_type ret = MC_TARGET_NONE;
6114 swp_entry_t ent = { .val = 0 };
6116 if (pte_present(ptent))
6117 page = mc_handle_present_pte(vma, addr, ptent);
6118 else if (pte_none_mostly(ptent))
6120 * PTE markers should be treated as a none pte here, separated
6121 * from other swap handling below.
6123 page = mc_handle_file_pte(vma, addr, ptent);
6124 else if (is_swap_pte(ptent))
6125 page = mc_handle_swap_pte(vma, ptent, &ent);
6127 if (target && page) {
6128 if (!trylock_page(page)) {
6133 * page_mapped() must be stable during the move. This
6134 * pte is locked, so if it's present, the page cannot
6135 * become unmapped. If it isn't, we have only partial
6136 * control over the mapped state: the page lock will
6137 * prevent new faults against pagecache and swapcache,
6138 * so an unmapped page cannot become mapped. However,
6139 * if the page is already mapped elsewhere, it can
6140 * unmap, and there is nothing we can do about it.
6141 * Alas, skip moving the page in this case.
6143 if (!pte_present(ptent) && page_mapped(page)) {
6150 if (!page && !ent.val)
6154 * Do only loose check w/o serialization.
6155 * mem_cgroup_move_account() checks the page is valid or
6156 * not under LRU exclusion.
6158 if (page_memcg(page) == mc.from) {
6159 ret = MC_TARGET_PAGE;
6160 if (is_device_private_page(page) ||
6161 is_device_coherent_page(page))
6162 ret = MC_TARGET_DEVICE;
6164 target->page = page;
6166 if (!ret || !target) {
6173 * There is a swap entry and a page doesn't exist or isn't charged.
6174 * But we cannot move a tail-page in a THP.
6176 if (ent.val && !ret && (!page || !PageTransCompound(page)) &&
6177 mem_cgroup_id(mc.from) == lookup_swap_cgroup_id(ent)) {
6178 ret = MC_TARGET_SWAP;
6185 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
6187 * We don't consider PMD mapped swapping or file mapped pages because THP does
6188 * not support them for now.
6189 * Caller should make sure that pmd_trans_huge(pmd) is true.
6191 static enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma,
6192 unsigned long addr, pmd_t pmd, union mc_target *target)
6194 struct page *page = NULL;
6195 enum mc_target_type ret = MC_TARGET_NONE;
6197 if (unlikely(is_swap_pmd(pmd))) {
6198 VM_BUG_ON(thp_migration_supported() &&
6199 !is_pmd_migration_entry(pmd));
6202 page = pmd_page(pmd);
6203 VM_BUG_ON_PAGE(!page || !PageHead(page), page);
6204 if (!(mc.flags & MOVE_ANON))
6206 if (page_memcg(page) == mc.from) {
6207 ret = MC_TARGET_PAGE;
6210 if (!trylock_page(page)) {
6212 return MC_TARGET_NONE;
6214 target->page = page;
6220 static inline enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma,
6221 unsigned long addr, pmd_t pmd, union mc_target *target)
6223 return MC_TARGET_NONE;
6227 static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd,
6228 unsigned long addr, unsigned long end,
6229 struct mm_walk *walk)
6231 struct vm_area_struct *vma = walk->vma;
6235 ptl = pmd_trans_huge_lock(pmd, vma);
6238 * Note their can not be MC_TARGET_DEVICE for now as we do not
6239 * support transparent huge page with MEMORY_DEVICE_PRIVATE but
6240 * this might change.
6242 if (get_mctgt_type_thp(vma, addr, *pmd, NULL) == MC_TARGET_PAGE)
6243 mc.precharge += HPAGE_PMD_NR;
6248 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
6251 for (; addr != end; pte++, addr += PAGE_SIZE)
6252 if (get_mctgt_type(vma, addr, ptep_get(pte), NULL))
6253 mc.precharge++; /* increment precharge temporarily */
6254 pte_unmap_unlock(pte - 1, ptl);
6260 static const struct mm_walk_ops precharge_walk_ops = {
6261 .pmd_entry = mem_cgroup_count_precharge_pte_range,
6262 .walk_lock = PGWALK_RDLOCK,
6265 static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm)
6267 unsigned long precharge;
6270 walk_page_range(mm, 0, ULONG_MAX, &precharge_walk_ops, NULL);
6271 mmap_read_unlock(mm);
6273 precharge = mc.precharge;
6279 static int mem_cgroup_precharge_mc(struct mm_struct *mm)
6281 unsigned long precharge = mem_cgroup_count_precharge(mm);
6283 VM_BUG_ON(mc.moving_task);
6284 mc.moving_task = current;
6285 return mem_cgroup_do_precharge(precharge);
6288 /* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */
6289 static void __mem_cgroup_clear_mc(void)
6291 struct mem_cgroup *from = mc.from;
6292 struct mem_cgroup *to = mc.to;
6294 /* we must uncharge all the leftover precharges from mc.to */
6296 mem_cgroup_cancel_charge(mc.to, mc.precharge);
6300 * we didn't uncharge from mc.from at mem_cgroup_move_account(), so
6301 * we must uncharge here.
6303 if (mc.moved_charge) {
6304 mem_cgroup_cancel_charge(mc.from, mc.moved_charge);
6305 mc.moved_charge = 0;
6307 /* we must fixup refcnts and charges */
6308 if (mc.moved_swap) {
6309 /* uncharge swap account from the old cgroup */
6310 if (!mem_cgroup_is_root(mc.from))
6311 page_counter_uncharge(&mc.from->memsw, mc.moved_swap);
6313 mem_cgroup_id_put_many(mc.from, mc.moved_swap);
6316 * we charged both to->memory and to->memsw, so we
6317 * should uncharge to->memory.
6319 if (!mem_cgroup_is_root(mc.to))
6320 page_counter_uncharge(&mc.to->memory, mc.moved_swap);
6324 memcg_oom_recover(from);
6325 memcg_oom_recover(to);
6326 wake_up_all(&mc.waitq);
6329 static void mem_cgroup_clear_mc(void)
6331 struct mm_struct *mm = mc.mm;
6334 * we must clear moving_task before waking up waiters at the end of
6337 mc.moving_task = NULL;
6338 __mem_cgroup_clear_mc();
6339 spin_lock(&mc.lock);
6343 spin_unlock(&mc.lock);
6348 static int mem_cgroup_can_attach(struct cgroup_taskset *tset)
6350 struct cgroup_subsys_state *css;
6351 struct mem_cgroup *memcg = NULL; /* unneeded init to make gcc happy */
6352 struct mem_cgroup *from;
6353 struct task_struct *leader, *p;
6354 struct mm_struct *mm;
6355 unsigned long move_flags;
6358 /* charge immigration isn't supported on the default hierarchy */
6359 if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
6363 * Multi-process migrations only happen on the default hierarchy
6364 * where charge immigration is not used. Perform charge
6365 * immigration if @tset contains a leader and whine if there are
6369 cgroup_taskset_for_each_leader(leader, css, tset) {
6372 memcg = mem_cgroup_from_css(css);
6378 * We are now committed to this value whatever it is. Changes in this
6379 * tunable will only affect upcoming migrations, not the current one.
6380 * So we need to save it, and keep it going.
6382 move_flags = READ_ONCE(memcg->move_charge_at_immigrate);
6386 from = mem_cgroup_from_task(p);
6388 VM_BUG_ON(from == memcg);
6390 mm = get_task_mm(p);
6393 /* We move charges only when we move a owner of the mm */
6394 if (mm->owner == p) {
6397 VM_BUG_ON(mc.precharge);
6398 VM_BUG_ON(mc.moved_charge);
6399 VM_BUG_ON(mc.moved_swap);
6401 spin_lock(&mc.lock);
6405 mc.flags = move_flags;
6406 spin_unlock(&mc.lock);
6407 /* We set mc.moving_task later */
6409 ret = mem_cgroup_precharge_mc(mm);
6411 mem_cgroup_clear_mc();
6418 static void mem_cgroup_cancel_attach(struct cgroup_taskset *tset)
6421 mem_cgroup_clear_mc();
6424 static int mem_cgroup_move_charge_pte_range(pmd_t *pmd,
6425 unsigned long addr, unsigned long end,
6426 struct mm_walk *walk)
6429 struct vm_area_struct *vma = walk->vma;
6432 enum mc_target_type target_type;
6433 union mc_target target;
6436 ptl = pmd_trans_huge_lock(pmd, vma);
6438 if (mc.precharge < HPAGE_PMD_NR) {
6442 target_type = get_mctgt_type_thp(vma, addr, *pmd, &target);
6443 if (target_type == MC_TARGET_PAGE) {
6445 if (isolate_lru_page(page)) {
6446 if (!mem_cgroup_move_account(page, true,
6448 mc.precharge -= HPAGE_PMD_NR;
6449 mc.moved_charge += HPAGE_PMD_NR;
6451 putback_lru_page(page);
6455 } else if (target_type == MC_TARGET_DEVICE) {
6457 if (!mem_cgroup_move_account(page, true,
6459 mc.precharge -= HPAGE_PMD_NR;
6460 mc.moved_charge += HPAGE_PMD_NR;
6470 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
6473 for (; addr != end; addr += PAGE_SIZE) {
6474 pte_t ptent = ptep_get(pte++);
6475 bool device = false;
6481 switch (get_mctgt_type(vma, addr, ptent, &target)) {
6482 case MC_TARGET_DEVICE:
6485 case MC_TARGET_PAGE:
6488 * We can have a part of the split pmd here. Moving it
6489 * can be done but it would be too convoluted so simply
6490 * ignore such a partial THP and keep it in original
6491 * memcg. There should be somebody mapping the head.
6493 if (PageTransCompound(page))
6495 if (!device && !isolate_lru_page(page))
6497 if (!mem_cgroup_move_account(page, false,
6500 /* we uncharge from mc.from later. */
6504 putback_lru_page(page);
6505 put: /* get_mctgt_type() gets & locks the page */
6509 case MC_TARGET_SWAP:
6511 if (!mem_cgroup_move_swap_account(ent, mc.from, mc.to)) {
6513 mem_cgroup_id_get_many(mc.to, 1);
6514 /* we fixup other refcnts and charges later. */
6522 pte_unmap_unlock(pte - 1, ptl);
6527 * We have consumed all precharges we got in can_attach().
6528 * We try charge one by one, but don't do any additional
6529 * charges to mc.to if we have failed in charge once in attach()
6532 ret = mem_cgroup_do_precharge(1);
6540 static const struct mm_walk_ops charge_walk_ops = {
6541 .pmd_entry = mem_cgroup_move_charge_pte_range,
6542 .walk_lock = PGWALK_RDLOCK,
6545 static void mem_cgroup_move_charge(void)
6547 lru_add_drain_all();
6549 * Signal folio_memcg_lock() to take the memcg's move_lock
6550 * while we're moving its pages to another memcg. Then wait
6551 * for already started RCU-only updates to finish.
6553 atomic_inc(&mc.from->moving_account);
6556 if (unlikely(!mmap_read_trylock(mc.mm))) {
6558 * Someone who are holding the mmap_lock might be waiting in
6559 * waitq. So we cancel all extra charges, wake up all waiters,
6560 * and retry. Because we cancel precharges, we might not be able
6561 * to move enough charges, but moving charge is a best-effort
6562 * feature anyway, so it wouldn't be a big problem.
6564 __mem_cgroup_clear_mc();
6569 * When we have consumed all precharges and failed in doing
6570 * additional charge, the page walk just aborts.
6572 walk_page_range(mc.mm, 0, ULONG_MAX, &charge_walk_ops, NULL);
6573 mmap_read_unlock(mc.mm);
6574 atomic_dec(&mc.from->moving_account);
6577 static void mem_cgroup_move_task(void)
6580 mem_cgroup_move_charge();
6581 mem_cgroup_clear_mc();
6585 #else /* !CONFIG_MMU */
6586 static int mem_cgroup_can_attach(struct cgroup_taskset *tset)
6590 static void mem_cgroup_cancel_attach(struct cgroup_taskset *tset)
6593 static void mem_cgroup_move_task(void)
6598 #ifdef CONFIG_MEMCG_KMEM
6599 static void mem_cgroup_fork(struct task_struct *task)
6602 * Set the update flag to cause task->objcg to be initialized lazily
6603 * on the first allocation. It can be done without any synchronization
6604 * because it's always performed on the current task, so does
6605 * current_objcg_update().
6607 task->objcg = (struct obj_cgroup *)CURRENT_OBJCG_UPDATE_FLAG;
6610 static void mem_cgroup_exit(struct task_struct *task)
6612 struct obj_cgroup *objcg = task->objcg;
6614 objcg = (struct obj_cgroup *)
6615 ((unsigned long)objcg & ~CURRENT_OBJCG_UPDATE_FLAG);
6617 obj_cgroup_put(objcg);
6620 * Some kernel allocations can happen after this point,
6621 * but let's ignore them. It can be done without any synchronization
6622 * because it's always performed on the current task, so does
6623 * current_objcg_update().
6629 #ifdef CONFIG_LRU_GEN
6630 static void mem_cgroup_lru_gen_attach(struct cgroup_taskset *tset)
6632 struct task_struct *task;
6633 struct cgroup_subsys_state *css;
6635 /* find the first leader if there is any */
6636 cgroup_taskset_for_each_leader(task, css, tset)
6643 if (task->mm && READ_ONCE(task->mm->owner) == task)
6644 lru_gen_migrate_mm(task->mm);
6648 static void mem_cgroup_lru_gen_attach(struct cgroup_taskset *tset) {}
6649 #endif /* CONFIG_LRU_GEN */
6651 #ifdef CONFIG_MEMCG_KMEM
6652 static void mem_cgroup_kmem_attach(struct cgroup_taskset *tset)
6654 struct task_struct *task;
6655 struct cgroup_subsys_state *css;
6657 cgroup_taskset_for_each(task, css, tset) {
6658 /* atomically set the update bit */
6659 set_bit(CURRENT_OBJCG_UPDATE_BIT, (unsigned long *)&task->objcg);
6663 static void mem_cgroup_kmem_attach(struct cgroup_taskset *tset) {}
6664 #endif /* CONFIG_MEMCG_KMEM */
6666 #if defined(CONFIG_LRU_GEN) || defined(CONFIG_MEMCG_KMEM)
6667 static void mem_cgroup_attach(struct cgroup_taskset *tset)
6669 mem_cgroup_lru_gen_attach(tset);
6670 mem_cgroup_kmem_attach(tset);
6674 static int seq_puts_memcg_tunable(struct seq_file *m, unsigned long value)
6676 if (value == PAGE_COUNTER_MAX)
6677 seq_puts(m, "max\n");
6679 seq_printf(m, "%llu\n", (u64)value * PAGE_SIZE);
6684 static u64 memory_current_read(struct cgroup_subsys_state *css,
6687 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
6689 return (u64)page_counter_read(&memcg->memory) * PAGE_SIZE;
6692 static u64 memory_peak_read(struct cgroup_subsys_state *css,
6695 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
6697 return (u64)memcg->memory.watermark * PAGE_SIZE;
6700 static int memory_min_show(struct seq_file *m, void *v)
6702 return seq_puts_memcg_tunable(m,
6703 READ_ONCE(mem_cgroup_from_seq(m)->memory.min));
6706 static ssize_t memory_min_write(struct kernfs_open_file *of,
6707 char *buf, size_t nbytes, loff_t off)
6709 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
6713 buf = strstrip(buf);
6714 err = page_counter_memparse(buf, "max", &min);
6718 page_counter_set_min(&memcg->memory, min);
6723 static int memory_low_show(struct seq_file *m, void *v)
6725 return seq_puts_memcg_tunable(m,
6726 READ_ONCE(mem_cgroup_from_seq(m)->memory.low));
6729 static ssize_t memory_low_write(struct kernfs_open_file *of,
6730 char *buf, size_t nbytes, loff_t off)
6732 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
6736 buf = strstrip(buf);
6737 err = page_counter_memparse(buf, "max", &low);
6741 page_counter_set_low(&memcg->memory, low);
6746 static int memory_high_show(struct seq_file *m, void *v)
6748 return seq_puts_memcg_tunable(m,
6749 READ_ONCE(mem_cgroup_from_seq(m)->memory.high));
6752 static ssize_t memory_high_write(struct kernfs_open_file *of,
6753 char *buf, size_t nbytes, loff_t off)
6755 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
6756 unsigned int nr_retries = MAX_RECLAIM_RETRIES;
6757 bool drained = false;
6761 buf = strstrip(buf);
6762 err = page_counter_memparse(buf, "max", &high);
6766 page_counter_set_high(&memcg->memory, high);
6769 unsigned long nr_pages = page_counter_read(&memcg->memory);
6770 unsigned long reclaimed;
6772 if (nr_pages <= high)
6775 if (signal_pending(current))
6779 drain_all_stock(memcg);
6784 reclaimed = try_to_free_mem_cgroup_pages(memcg, nr_pages - high,
6785 GFP_KERNEL, MEMCG_RECLAIM_MAY_SWAP);
6787 if (!reclaimed && !nr_retries--)
6791 memcg_wb_domain_size_changed(memcg);
6795 static int memory_max_show(struct seq_file *m, void *v)
6797 return seq_puts_memcg_tunable(m,
6798 READ_ONCE(mem_cgroup_from_seq(m)->memory.max));
6801 static ssize_t memory_max_write(struct kernfs_open_file *of,
6802 char *buf, size_t nbytes, loff_t off)
6804 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
6805 unsigned int nr_reclaims = MAX_RECLAIM_RETRIES;
6806 bool drained = false;
6810 buf = strstrip(buf);
6811 err = page_counter_memparse(buf, "max", &max);
6815 xchg(&memcg->memory.max, max);
6818 unsigned long nr_pages = page_counter_read(&memcg->memory);
6820 if (nr_pages <= max)
6823 if (signal_pending(current))
6827 drain_all_stock(memcg);
6833 if (!try_to_free_mem_cgroup_pages(memcg, nr_pages - max,
6834 GFP_KERNEL, MEMCG_RECLAIM_MAY_SWAP))
6839 memcg_memory_event(memcg, MEMCG_OOM);
6840 if (!mem_cgroup_out_of_memory(memcg, GFP_KERNEL, 0))
6844 memcg_wb_domain_size_changed(memcg);
6849 * Note: don't forget to update the 'samples/cgroup/memcg_event_listener'
6850 * if any new events become available.
6852 static void __memory_events_show(struct seq_file *m, atomic_long_t *events)
6854 seq_printf(m, "low %lu\n", atomic_long_read(&events[MEMCG_LOW]));
6855 seq_printf(m, "high %lu\n", atomic_long_read(&events[MEMCG_HIGH]));
6856 seq_printf(m, "max %lu\n", atomic_long_read(&events[MEMCG_MAX]));
6857 seq_printf(m, "oom %lu\n", atomic_long_read(&events[MEMCG_OOM]));
6858 seq_printf(m, "oom_kill %lu\n",
6859 atomic_long_read(&events[MEMCG_OOM_KILL]));
6860 seq_printf(m, "oom_group_kill %lu\n",
6861 atomic_long_read(&events[MEMCG_OOM_GROUP_KILL]));
6864 static int memory_events_show(struct seq_file *m, void *v)
6866 struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
6868 __memory_events_show(m, memcg->memory_events);
6872 static int memory_events_local_show(struct seq_file *m, void *v)
6874 struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
6876 __memory_events_show(m, memcg->memory_events_local);
6880 static int memory_stat_show(struct seq_file *m, void *v)
6882 struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
6883 char *buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
6888 seq_buf_init(&s, buf, PAGE_SIZE);
6889 memory_stat_format(memcg, &s);
6896 static inline unsigned long lruvec_page_state_output(struct lruvec *lruvec,
6899 return lruvec_page_state(lruvec, item) *
6900 memcg_page_state_output_unit(item);
6903 static int memory_numa_stat_show(struct seq_file *m, void *v)
6906 struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
6908 mem_cgroup_flush_stats(memcg);
6910 for (i = 0; i < ARRAY_SIZE(memory_stats); i++) {
6913 if (memory_stats[i].idx >= NR_VM_NODE_STAT_ITEMS)
6916 seq_printf(m, "%s", memory_stats[i].name);
6917 for_each_node_state(nid, N_MEMORY) {
6919 struct lruvec *lruvec;
6921 lruvec = mem_cgroup_lruvec(memcg, NODE_DATA(nid));
6922 size = lruvec_page_state_output(lruvec,
6923 memory_stats[i].idx);
6924 seq_printf(m, " N%d=%llu", nid, size);
6933 static int memory_oom_group_show(struct seq_file *m, void *v)
6935 struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
6937 seq_printf(m, "%d\n", READ_ONCE(memcg->oom_group));
6942 static ssize_t memory_oom_group_write(struct kernfs_open_file *of,
6943 char *buf, size_t nbytes, loff_t off)
6945 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
6948 buf = strstrip(buf);
6952 ret = kstrtoint(buf, 0, &oom_group);
6956 if (oom_group != 0 && oom_group != 1)
6959 WRITE_ONCE(memcg->oom_group, oom_group);
6964 static ssize_t memory_reclaim(struct kernfs_open_file *of, char *buf,
6965 size_t nbytes, loff_t off)
6967 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
6968 unsigned int nr_retries = MAX_RECLAIM_RETRIES;
6969 unsigned long nr_to_reclaim, nr_reclaimed = 0;
6970 unsigned int reclaim_options;
6973 buf = strstrip(buf);
6974 err = page_counter_memparse(buf, "", &nr_to_reclaim);
6978 reclaim_options = MEMCG_RECLAIM_MAY_SWAP | MEMCG_RECLAIM_PROACTIVE;
6979 while (nr_reclaimed < nr_to_reclaim) {
6980 unsigned long reclaimed;
6982 if (signal_pending(current))
6986 * This is the final attempt, drain percpu lru caches in the
6987 * hope of introducing more evictable pages for
6988 * try_to_free_mem_cgroup_pages().
6991 lru_add_drain_all();
6993 reclaimed = try_to_free_mem_cgroup_pages(memcg,
6994 min(nr_to_reclaim - nr_reclaimed, SWAP_CLUSTER_MAX),
6995 GFP_KERNEL, reclaim_options);
6997 if (!reclaimed && !nr_retries--)
7000 nr_reclaimed += reclaimed;
7006 static struct cftype memory_files[] = {
7009 .flags = CFTYPE_NOT_ON_ROOT,
7010 .read_u64 = memory_current_read,
7014 .flags = CFTYPE_NOT_ON_ROOT,
7015 .read_u64 = memory_peak_read,
7019 .flags = CFTYPE_NOT_ON_ROOT,
7020 .seq_show = memory_min_show,
7021 .write = memory_min_write,
7025 .flags = CFTYPE_NOT_ON_ROOT,
7026 .seq_show = memory_low_show,
7027 .write = memory_low_write,
7031 .flags = CFTYPE_NOT_ON_ROOT,
7032 .seq_show = memory_high_show,
7033 .write = memory_high_write,
7037 .flags = CFTYPE_NOT_ON_ROOT,
7038 .seq_show = memory_max_show,
7039 .write = memory_max_write,
7043 .flags = CFTYPE_NOT_ON_ROOT,
7044 .file_offset = offsetof(struct mem_cgroup, events_file),
7045 .seq_show = memory_events_show,
7048 .name = "events.local",
7049 .flags = CFTYPE_NOT_ON_ROOT,
7050 .file_offset = offsetof(struct mem_cgroup, events_local_file),
7051 .seq_show = memory_events_local_show,
7055 .seq_show = memory_stat_show,
7059 .name = "numa_stat",
7060 .seq_show = memory_numa_stat_show,
7064 .name = "oom.group",
7065 .flags = CFTYPE_NOT_ON_ROOT | CFTYPE_NS_DELEGATABLE,
7066 .seq_show = memory_oom_group_show,
7067 .write = memory_oom_group_write,
7071 .flags = CFTYPE_NS_DELEGATABLE,
7072 .write = memory_reclaim,
7077 struct cgroup_subsys memory_cgrp_subsys = {
7078 .css_alloc = mem_cgroup_css_alloc,
7079 .css_online = mem_cgroup_css_online,
7080 .css_offline = mem_cgroup_css_offline,
7081 .css_released = mem_cgroup_css_released,
7082 .css_free = mem_cgroup_css_free,
7083 .css_reset = mem_cgroup_css_reset,
7084 .css_rstat_flush = mem_cgroup_css_rstat_flush,
7085 .can_attach = mem_cgroup_can_attach,
7086 #if defined(CONFIG_LRU_GEN) || defined(CONFIG_MEMCG_KMEM)
7087 .attach = mem_cgroup_attach,
7089 .cancel_attach = mem_cgroup_cancel_attach,
7090 .post_attach = mem_cgroup_move_task,
7091 #ifdef CONFIG_MEMCG_KMEM
7092 .fork = mem_cgroup_fork,
7093 .exit = mem_cgroup_exit,
7095 .dfl_cftypes = memory_files,
7096 .legacy_cftypes = mem_cgroup_legacy_files,
7101 * This function calculates an individual cgroup's effective
7102 * protection which is derived from its own memory.min/low, its
7103 * parent's and siblings' settings, as well as the actual memory
7104 * distribution in the tree.
7106 * The following rules apply to the effective protection values:
7108 * 1. At the first level of reclaim, effective protection is equal to
7109 * the declared protection in memory.min and memory.low.
7111 * 2. To enable safe delegation of the protection configuration, at
7112 * subsequent levels the effective protection is capped to the
7113 * parent's effective protection.
7115 * 3. To make complex and dynamic subtrees easier to configure, the
7116 * user is allowed to overcommit the declared protection at a given
7117 * level. If that is the case, the parent's effective protection is
7118 * distributed to the children in proportion to how much protection
7119 * they have declared and how much of it they are utilizing.
7121 * This makes distribution proportional, but also work-conserving:
7122 * if one cgroup claims much more protection than it uses memory,
7123 * the unused remainder is available to its siblings.
7125 * 4. Conversely, when the declared protection is undercommitted at a
7126 * given level, the distribution of the larger parental protection
7127 * budget is NOT proportional. A cgroup's protection from a sibling
7128 * is capped to its own memory.min/low setting.
7130 * 5. However, to allow protecting recursive subtrees from each other
7131 * without having to declare each individual cgroup's fixed share
7132 * of the ancestor's claim to protection, any unutilized -
7133 * "floating" - protection from up the tree is distributed in
7134 * proportion to each cgroup's *usage*. This makes the protection
7135 * neutral wrt sibling cgroups and lets them compete freely over
7136 * the shared parental protection budget, but it protects the
7137 * subtree as a whole from neighboring subtrees.
7139 * Note that 4. and 5. are not in conflict: 4. is about protecting
7140 * against immediate siblings whereas 5. is about protecting against
7141 * neighboring subtrees.
7143 static unsigned long effective_protection(unsigned long usage,
7144 unsigned long parent_usage,
7145 unsigned long setting,
7146 unsigned long parent_effective,
7147 unsigned long siblings_protected)
7149 unsigned long protected;
7152 protected = min(usage, setting);
7154 * If all cgroups at this level combined claim and use more
7155 * protection than what the parent affords them, distribute
7156 * shares in proportion to utilization.
7158 * We are using actual utilization rather than the statically
7159 * claimed protection in order to be work-conserving: claimed
7160 * but unused protection is available to siblings that would
7161 * otherwise get a smaller chunk than what they claimed.
7163 if (siblings_protected > parent_effective)
7164 return protected * parent_effective / siblings_protected;
7167 * Ok, utilized protection of all children is within what the
7168 * parent affords them, so we know whatever this child claims
7169 * and utilizes is effectively protected.
7171 * If there is unprotected usage beyond this value, reclaim
7172 * will apply pressure in proportion to that amount.
7174 * If there is unutilized protection, the cgroup will be fully
7175 * shielded from reclaim, but we do return a smaller value for
7176 * protection than what the group could enjoy in theory. This
7177 * is okay. With the overcommit distribution above, effective
7178 * protection is always dependent on how memory is actually
7179 * consumed among the siblings anyway.
7184 * If the children aren't claiming (all of) the protection
7185 * afforded to them by the parent, distribute the remainder in
7186 * proportion to the (unprotected) memory of each cgroup. That
7187 * way, cgroups that aren't explicitly prioritized wrt each
7188 * other compete freely over the allowance, but they are
7189 * collectively protected from neighboring trees.
7191 * We're using unprotected memory for the weight so that if
7192 * some cgroups DO claim explicit protection, we don't protect
7193 * the same bytes twice.
7195 * Check both usage and parent_usage against the respective
7196 * protected values. One should imply the other, but they
7197 * aren't read atomically - make sure the division is sane.
7199 if (!(cgrp_dfl_root.flags & CGRP_ROOT_MEMORY_RECURSIVE_PROT))
7201 if (parent_effective > siblings_protected &&
7202 parent_usage > siblings_protected &&
7203 usage > protected) {
7204 unsigned long unclaimed;
7206 unclaimed = parent_effective - siblings_protected;
7207 unclaimed *= usage - protected;
7208 unclaimed /= parent_usage - siblings_protected;
7217 * mem_cgroup_calculate_protection - check if memory consumption is in the normal range
7218 * @root: the top ancestor of the sub-tree being checked
7219 * @memcg: the memory cgroup to check
7221 * WARNING: This function is not stateless! It can only be used as part
7222 * of a top-down tree iteration, not for isolated queries.
7224 void mem_cgroup_calculate_protection(struct mem_cgroup *root,
7225 struct mem_cgroup *memcg)
7227 unsigned long usage, parent_usage;
7228 struct mem_cgroup *parent;
7230 if (mem_cgroup_disabled())
7234 root = root_mem_cgroup;
7237 * Effective values of the reclaim targets are ignored so they
7238 * can be stale. Have a look at mem_cgroup_protection for more
7240 * TODO: calculation should be more robust so that we do not need
7241 * that special casing.
7246 usage = page_counter_read(&memcg->memory);
7250 parent = parent_mem_cgroup(memcg);
7252 if (parent == root) {
7253 memcg->memory.emin = READ_ONCE(memcg->memory.min);
7254 memcg->memory.elow = READ_ONCE(memcg->memory.low);
7258 parent_usage = page_counter_read(&parent->memory);
7260 WRITE_ONCE(memcg->memory.emin, effective_protection(usage, parent_usage,
7261 READ_ONCE(memcg->memory.min),
7262 READ_ONCE(parent->memory.emin),
7263 atomic_long_read(&parent->memory.children_min_usage)));
7265 WRITE_ONCE(memcg->memory.elow, effective_protection(usage, parent_usage,
7266 READ_ONCE(memcg->memory.low),
7267 READ_ONCE(parent->memory.elow),
7268 atomic_long_read(&parent->memory.children_low_usage)));
7271 static int charge_memcg(struct folio *folio, struct mem_cgroup *memcg,
7276 ret = try_charge(memcg, gfp, folio_nr_pages(folio));
7280 mem_cgroup_commit_charge(folio, memcg);
7285 int __mem_cgroup_charge(struct folio *folio, struct mm_struct *mm, gfp_t gfp)
7287 struct mem_cgroup *memcg;
7290 memcg = get_mem_cgroup_from_mm(mm);
7291 ret = charge_memcg(folio, memcg, gfp);
7292 css_put(&memcg->css);
7298 * mem_cgroup_hugetlb_try_charge - try to charge the memcg for a hugetlb folio
7299 * @memcg: memcg to charge.
7300 * @gfp: reclaim mode.
7301 * @nr_pages: number of pages to charge.
7303 * This function is called when allocating a huge page folio to determine if
7304 * the memcg has the capacity for it. It does not commit the charge yet,
7305 * as the hugetlb folio itself has not been obtained from the hugetlb pool.
7307 * Once we have obtained the hugetlb folio, we can call
7308 * mem_cgroup_commit_charge() to commit the charge. If we fail to obtain the
7309 * folio, we should instead call mem_cgroup_cancel_charge() to undo the effect
7312 * Returns 0 on success. Otherwise, an error code is returned.
7314 int mem_cgroup_hugetlb_try_charge(struct mem_cgroup *memcg, gfp_t gfp,
7318 * If hugetlb memcg charging is not enabled, do not fail hugetlb allocation,
7319 * but do not attempt to commit charge later (or cancel on error) either.
7321 if (mem_cgroup_disabled() || !memcg ||
7322 !cgroup_subsys_on_dfl(memory_cgrp_subsys) ||
7323 !(cgrp_dfl_root.flags & CGRP_ROOT_MEMORY_HUGETLB_ACCOUNTING))
7326 if (try_charge(memcg, gfp, nr_pages))
7333 * mem_cgroup_swapin_charge_folio - Charge a newly allocated folio for swapin.
7334 * @folio: folio to charge.
7335 * @mm: mm context of the victim
7336 * @gfp: reclaim mode
7337 * @entry: swap entry for which the folio is allocated
7339 * This function charges a folio allocated for swapin. Please call this before
7340 * adding the folio to the swapcache.
7342 * Returns 0 on success. Otherwise, an error code is returned.
7344 int mem_cgroup_swapin_charge_folio(struct folio *folio, struct mm_struct *mm,
7345 gfp_t gfp, swp_entry_t entry)
7347 struct mem_cgroup *memcg;
7351 if (mem_cgroup_disabled())
7354 id = lookup_swap_cgroup_id(entry);
7356 memcg = mem_cgroup_from_id(id);
7357 if (!memcg || !css_tryget_online(&memcg->css))
7358 memcg = get_mem_cgroup_from_mm(mm);
7361 ret = charge_memcg(folio, memcg, gfp);
7363 css_put(&memcg->css);
7368 * mem_cgroup_swapin_uncharge_swap - uncharge swap slot
7369 * @entry: swap entry for which the page is charged
7371 * Call this function after successfully adding the charged page to swapcache.
7373 * Note: This function assumes the page for which swap slot is being uncharged
7376 void mem_cgroup_swapin_uncharge_swap(swp_entry_t entry)
7379 * Cgroup1's unified memory+swap counter has been charged with the
7380 * new swapcache page, finish the transfer by uncharging the swap
7381 * slot. The swap slot would also get uncharged when it dies, but
7382 * it can stick around indefinitely and we'd count the page twice
7385 * Cgroup2 has separate resource counters for memory and swap,
7386 * so this is a non-issue here. Memory and swap charge lifetimes
7387 * correspond 1:1 to page and swap slot lifetimes: we charge the
7388 * page to memory here, and uncharge swap when the slot is freed.
7390 if (!mem_cgroup_disabled() && do_memsw_account()) {
7392 * The swap entry might not get freed for a long time,
7393 * let's not wait for it. The page already received a
7394 * memory+swap charge, drop the swap entry duplicate.
7396 mem_cgroup_uncharge_swap(entry, 1);
7400 struct uncharge_gather {
7401 struct mem_cgroup *memcg;
7402 unsigned long nr_memory;
7403 unsigned long pgpgout;
7404 unsigned long nr_kmem;
7408 static inline void uncharge_gather_clear(struct uncharge_gather *ug)
7410 memset(ug, 0, sizeof(*ug));
7413 static void uncharge_batch(const struct uncharge_gather *ug)
7415 unsigned long flags;
7417 if (ug->nr_memory) {
7418 page_counter_uncharge(&ug->memcg->memory, ug->nr_memory);
7419 if (do_memsw_account())
7420 page_counter_uncharge(&ug->memcg->memsw, ug->nr_memory);
7422 memcg_account_kmem(ug->memcg, -ug->nr_kmem);
7423 memcg_oom_recover(ug->memcg);
7426 local_irq_save(flags);
7427 __count_memcg_events(ug->memcg, PGPGOUT, ug->pgpgout);
7428 __this_cpu_add(ug->memcg->vmstats_percpu->nr_page_events, ug->nr_memory);
7429 memcg_check_events(ug->memcg, ug->nid);
7430 local_irq_restore(flags);
7432 /* drop reference from uncharge_folio */
7433 css_put(&ug->memcg->css);
7436 static void uncharge_folio(struct folio *folio, struct uncharge_gather *ug)
7439 struct mem_cgroup *memcg;
7440 struct obj_cgroup *objcg;
7442 VM_BUG_ON_FOLIO(folio_test_lru(folio), folio);
7445 * Nobody should be changing or seriously looking at
7446 * folio memcg or objcg at this point, we have fully
7447 * exclusive access to the folio.
7449 if (folio_memcg_kmem(folio)) {
7450 objcg = __folio_objcg(folio);
7452 * This get matches the put at the end of the function and
7453 * kmem pages do not hold memcg references anymore.
7455 memcg = get_mem_cgroup_from_objcg(objcg);
7457 memcg = __folio_memcg(folio);
7463 if (ug->memcg != memcg) {
7466 uncharge_gather_clear(ug);
7469 ug->nid = folio_nid(folio);
7471 /* pairs with css_put in uncharge_batch */
7472 css_get(&memcg->css);
7475 nr_pages = folio_nr_pages(folio);
7477 if (folio_memcg_kmem(folio)) {
7478 ug->nr_memory += nr_pages;
7479 ug->nr_kmem += nr_pages;
7481 folio->memcg_data = 0;
7482 obj_cgroup_put(objcg);
7484 /* LRU pages aren't accounted at the root level */
7485 if (!mem_cgroup_is_root(memcg))
7486 ug->nr_memory += nr_pages;
7489 folio->memcg_data = 0;
7492 css_put(&memcg->css);
7495 void __mem_cgroup_uncharge(struct folio *folio)
7497 struct uncharge_gather ug;
7499 /* Don't touch folio->lru of any random page, pre-check: */
7500 if (!folio_memcg(folio))
7503 uncharge_gather_clear(&ug);
7504 uncharge_folio(folio, &ug);
7505 uncharge_batch(&ug);
7509 * __mem_cgroup_uncharge_list - uncharge a list of page
7510 * @page_list: list of pages to uncharge
7512 * Uncharge a list of pages previously charged with
7513 * __mem_cgroup_charge().
7515 void __mem_cgroup_uncharge_list(struct list_head *page_list)
7517 struct uncharge_gather ug;
7518 struct folio *folio;
7520 uncharge_gather_clear(&ug);
7521 list_for_each_entry(folio, page_list, lru)
7522 uncharge_folio(folio, &ug);
7524 uncharge_batch(&ug);
7528 * mem_cgroup_replace_folio - Charge a folio's replacement.
7529 * @old: Currently circulating folio.
7530 * @new: Replacement folio.
7532 * Charge @new as a replacement folio for @old. @old will
7533 * be uncharged upon free. This is only used by the page cache
7534 * (in replace_page_cache_folio()).
7536 * Both folios must be locked, @new->mapping must be set up.
7538 void mem_cgroup_replace_folio(struct folio *old, struct folio *new)
7540 struct mem_cgroup *memcg;
7541 long nr_pages = folio_nr_pages(new);
7542 unsigned long flags;
7544 VM_BUG_ON_FOLIO(!folio_test_locked(old), old);
7545 VM_BUG_ON_FOLIO(!folio_test_locked(new), new);
7546 VM_BUG_ON_FOLIO(folio_test_anon(old) != folio_test_anon(new), new);
7547 VM_BUG_ON_FOLIO(folio_nr_pages(old) != nr_pages, new);
7549 if (mem_cgroup_disabled())
7552 /* Page cache replacement: new folio already charged? */
7553 if (folio_memcg(new))
7556 memcg = folio_memcg(old);
7557 VM_WARN_ON_ONCE_FOLIO(!memcg, old);
7561 /* Force-charge the new page. The old one will be freed soon */
7562 if (!mem_cgroup_is_root(memcg)) {
7563 page_counter_charge(&memcg->memory, nr_pages);
7564 if (do_memsw_account())
7565 page_counter_charge(&memcg->memsw, nr_pages);
7568 css_get(&memcg->css);
7569 commit_charge(new, memcg);
7571 local_irq_save(flags);
7572 mem_cgroup_charge_statistics(memcg, nr_pages);
7573 memcg_check_events(memcg, folio_nid(new));
7574 local_irq_restore(flags);
7578 * mem_cgroup_migrate - Transfer the memcg data from the old to the new folio.
7579 * @old: Currently circulating folio.
7580 * @new: Replacement folio.
7582 * Transfer the memcg data from the old folio to the new folio for migration.
7583 * The old folio's data info will be cleared. Note that the memory counters
7584 * will remain unchanged throughout the process.
7586 * Both folios must be locked, @new->mapping must be set up.
7588 void mem_cgroup_migrate(struct folio *old, struct folio *new)
7590 struct mem_cgroup *memcg;
7592 VM_BUG_ON_FOLIO(!folio_test_locked(old), old);
7593 VM_BUG_ON_FOLIO(!folio_test_locked(new), new);
7594 VM_BUG_ON_FOLIO(folio_test_anon(old) != folio_test_anon(new), new);
7595 VM_BUG_ON_FOLIO(folio_nr_pages(old) != folio_nr_pages(new), new);
7597 if (mem_cgroup_disabled())
7600 memcg = folio_memcg(old);
7602 * Note that it is normal to see !memcg for a hugetlb folio.
7603 * For e.g, itt could have been allocated when memory_hugetlb_accounting
7606 VM_WARN_ON_ONCE_FOLIO(!folio_test_hugetlb(old) && !memcg, old);
7610 /* Transfer the charge and the css ref */
7611 commit_charge(new, memcg);
7613 * If the old folio is a large folio and is in the split queue, it needs
7614 * to be removed from the split queue now, in case getting an incorrect
7615 * split queue in destroy_large_folio() after the memcg of the old folio
7618 * In addition, the old folio is about to be freed after migration, so
7619 * removing from the split queue a bit earlier seems reasonable.
7621 if (folio_test_large(old) && folio_test_large_rmappable(old))
7622 folio_undo_large_rmappable(old);
7623 old->memcg_data = 0;
7626 DEFINE_STATIC_KEY_FALSE(memcg_sockets_enabled_key);
7627 EXPORT_SYMBOL(memcg_sockets_enabled_key);
7629 void mem_cgroup_sk_alloc(struct sock *sk)
7631 struct mem_cgroup *memcg;
7633 if (!mem_cgroup_sockets_enabled)
7636 /* Do not associate the sock with unrelated interrupted task's memcg. */
7641 memcg = mem_cgroup_from_task(current);
7642 if (mem_cgroup_is_root(memcg))
7644 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && !memcg->tcpmem_active)
7646 if (css_tryget(&memcg->css))
7647 sk->sk_memcg = memcg;
7652 void mem_cgroup_sk_free(struct sock *sk)
7655 css_put(&sk->sk_memcg->css);
7659 * mem_cgroup_charge_skmem - charge socket memory
7660 * @memcg: memcg to charge
7661 * @nr_pages: number of pages to charge
7662 * @gfp_mask: reclaim mode
7664 * Charges @nr_pages to @memcg. Returns %true if the charge fit within
7665 * @memcg's configured limit, %false if it doesn't.
7667 bool mem_cgroup_charge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages,
7670 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) {
7671 struct page_counter *fail;
7673 if (page_counter_try_charge(&memcg->tcpmem, nr_pages, &fail)) {
7674 memcg->tcpmem_pressure = 0;
7677 memcg->tcpmem_pressure = 1;
7678 if (gfp_mask & __GFP_NOFAIL) {
7679 page_counter_charge(&memcg->tcpmem, nr_pages);
7685 if (try_charge(memcg, gfp_mask, nr_pages) == 0) {
7686 mod_memcg_state(memcg, MEMCG_SOCK, nr_pages);
7694 * mem_cgroup_uncharge_skmem - uncharge socket memory
7695 * @memcg: memcg to uncharge
7696 * @nr_pages: number of pages to uncharge
7698 void mem_cgroup_uncharge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages)
7700 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) {
7701 page_counter_uncharge(&memcg->tcpmem, nr_pages);
7705 mod_memcg_state(memcg, MEMCG_SOCK, -nr_pages);
7707 refill_stock(memcg, nr_pages);
7710 static int __init cgroup_memory(char *s)
7714 while ((token = strsep(&s, ",")) != NULL) {
7717 if (!strcmp(token, "nosocket"))
7718 cgroup_memory_nosocket = true;
7719 if (!strcmp(token, "nokmem"))
7720 cgroup_memory_nokmem = true;
7721 if (!strcmp(token, "nobpf"))
7722 cgroup_memory_nobpf = true;
7726 __setup("cgroup.memory=", cgroup_memory);
7729 * subsys_initcall() for memory controller.
7731 * Some parts like memcg_hotplug_cpu_dead() have to be initialized from this
7732 * context because of lock dependencies (cgroup_lock -> cpu hotplug) but
7733 * basically everything that doesn't depend on a specific mem_cgroup structure
7734 * should be initialized from here.
7736 static int __init mem_cgroup_init(void)
7741 * Currently s32 type (can refer to struct batched_lruvec_stat) is
7742 * used for per-memcg-per-cpu caching of per-node statistics. In order
7743 * to work fine, we should make sure that the overfill threshold can't
7744 * exceed S32_MAX / PAGE_SIZE.
7746 BUILD_BUG_ON(MEMCG_CHARGE_BATCH > S32_MAX / PAGE_SIZE);
7748 cpuhp_setup_state_nocalls(CPUHP_MM_MEMCQ_DEAD, "mm/memctrl:dead", NULL,
7749 memcg_hotplug_cpu_dead);
7751 for_each_possible_cpu(cpu)
7752 INIT_WORK(&per_cpu_ptr(&memcg_stock, cpu)->work,
7755 for_each_node(node) {
7756 struct mem_cgroup_tree_per_node *rtpn;
7758 rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL, node);
7760 rtpn->rb_root = RB_ROOT;
7761 rtpn->rb_rightmost = NULL;
7762 spin_lock_init(&rtpn->lock);
7763 soft_limit_tree.rb_tree_per_node[node] = rtpn;
7768 subsys_initcall(mem_cgroup_init);
7771 static struct mem_cgroup *mem_cgroup_id_get_online(struct mem_cgroup *memcg)
7773 while (!refcount_inc_not_zero(&memcg->id.ref)) {
7775 * The root cgroup cannot be destroyed, so it's refcount must
7778 if (WARN_ON_ONCE(mem_cgroup_is_root(memcg))) {
7782 memcg = parent_mem_cgroup(memcg);
7784 memcg = root_mem_cgroup;
7790 * mem_cgroup_swapout - transfer a memsw charge to swap
7791 * @folio: folio whose memsw charge to transfer
7792 * @entry: swap entry to move the charge to
7794 * Transfer the memsw charge of @folio to @entry.
7796 void mem_cgroup_swapout(struct folio *folio, swp_entry_t entry)
7798 struct mem_cgroup *memcg, *swap_memcg;
7799 unsigned int nr_entries;
7800 unsigned short oldid;
7802 VM_BUG_ON_FOLIO(folio_test_lru(folio), folio);
7803 VM_BUG_ON_FOLIO(folio_ref_count(folio), folio);
7805 if (mem_cgroup_disabled())
7808 if (!do_memsw_account())
7811 memcg = folio_memcg(folio);
7813 VM_WARN_ON_ONCE_FOLIO(!memcg, folio);
7818 * In case the memcg owning these pages has been offlined and doesn't
7819 * have an ID allocated to it anymore, charge the closest online
7820 * ancestor for the swap instead and transfer the memory+swap charge.
7822 swap_memcg = mem_cgroup_id_get_online(memcg);
7823 nr_entries = folio_nr_pages(folio);
7824 /* Get references for the tail pages, too */
7826 mem_cgroup_id_get_many(swap_memcg, nr_entries - 1);
7827 oldid = swap_cgroup_record(entry, mem_cgroup_id(swap_memcg),
7829 VM_BUG_ON_FOLIO(oldid, folio);
7830 mod_memcg_state(swap_memcg, MEMCG_SWAP, nr_entries);
7832 folio->memcg_data = 0;
7834 if (!mem_cgroup_is_root(memcg))
7835 page_counter_uncharge(&memcg->memory, nr_entries);
7837 if (memcg != swap_memcg) {
7838 if (!mem_cgroup_is_root(swap_memcg))
7839 page_counter_charge(&swap_memcg->memsw, nr_entries);
7840 page_counter_uncharge(&memcg->memsw, nr_entries);
7844 * Interrupts should be disabled here because the caller holds the
7845 * i_pages lock which is taken with interrupts-off. It is
7846 * important here to have the interrupts disabled because it is the
7847 * only synchronisation we have for updating the per-CPU variables.
7850 mem_cgroup_charge_statistics(memcg, -nr_entries);
7851 memcg_stats_unlock();
7852 memcg_check_events(memcg, folio_nid(folio));
7854 css_put(&memcg->css);
7858 * __mem_cgroup_try_charge_swap - try charging swap space for a folio
7859 * @folio: folio being added to swap
7860 * @entry: swap entry to charge
7862 * Try to charge @folio's memcg for the swap space at @entry.
7864 * Returns 0 on success, -ENOMEM on failure.
7866 int __mem_cgroup_try_charge_swap(struct folio *folio, swp_entry_t entry)
7868 unsigned int nr_pages = folio_nr_pages(folio);
7869 struct page_counter *counter;
7870 struct mem_cgroup *memcg;
7871 unsigned short oldid;
7873 if (do_memsw_account())
7876 memcg = folio_memcg(folio);
7878 VM_WARN_ON_ONCE_FOLIO(!memcg, folio);
7883 memcg_memory_event(memcg, MEMCG_SWAP_FAIL);
7887 memcg = mem_cgroup_id_get_online(memcg);
7889 if (!mem_cgroup_is_root(memcg) &&
7890 !page_counter_try_charge(&memcg->swap, nr_pages, &counter)) {
7891 memcg_memory_event(memcg, MEMCG_SWAP_MAX);
7892 memcg_memory_event(memcg, MEMCG_SWAP_FAIL);
7893 mem_cgroup_id_put(memcg);
7897 /* Get references for the tail pages, too */
7899 mem_cgroup_id_get_many(memcg, nr_pages - 1);
7900 oldid = swap_cgroup_record(entry, mem_cgroup_id(memcg), nr_pages);
7901 VM_BUG_ON_FOLIO(oldid, folio);
7902 mod_memcg_state(memcg, MEMCG_SWAP, nr_pages);
7908 * __mem_cgroup_uncharge_swap - uncharge swap space
7909 * @entry: swap entry to uncharge
7910 * @nr_pages: the amount of swap space to uncharge
7912 void __mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages)
7914 struct mem_cgroup *memcg;
7917 id = swap_cgroup_record(entry, 0, nr_pages);
7919 memcg = mem_cgroup_from_id(id);
7921 if (!mem_cgroup_is_root(memcg)) {
7922 if (do_memsw_account())
7923 page_counter_uncharge(&memcg->memsw, nr_pages);
7925 page_counter_uncharge(&memcg->swap, nr_pages);
7927 mod_memcg_state(memcg, MEMCG_SWAP, -nr_pages);
7928 mem_cgroup_id_put_many(memcg, nr_pages);
7933 long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg)
7935 long nr_swap_pages = get_nr_swap_pages();
7937 if (mem_cgroup_disabled() || do_memsw_account())
7938 return nr_swap_pages;
7939 for (; !mem_cgroup_is_root(memcg); memcg = parent_mem_cgroup(memcg))
7940 nr_swap_pages = min_t(long, nr_swap_pages,
7941 READ_ONCE(memcg->swap.max) -
7942 page_counter_read(&memcg->swap));
7943 return nr_swap_pages;
7946 bool mem_cgroup_swap_full(struct folio *folio)
7948 struct mem_cgroup *memcg;
7950 VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio);
7954 if (do_memsw_account())
7957 memcg = folio_memcg(folio);
7961 for (; !mem_cgroup_is_root(memcg); memcg = parent_mem_cgroup(memcg)) {
7962 unsigned long usage = page_counter_read(&memcg->swap);
7964 if (usage * 2 >= READ_ONCE(memcg->swap.high) ||
7965 usage * 2 >= READ_ONCE(memcg->swap.max))
7972 static int __init setup_swap_account(char *s)
7974 pr_warn_once("The swapaccount= commandline option is deprecated. "
7975 "Please report your usecase to linux-mm@kvack.org if you "
7976 "depend on this functionality.\n");
7979 __setup("swapaccount=", setup_swap_account);
7981 static u64 swap_current_read(struct cgroup_subsys_state *css,
7984 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
7986 return (u64)page_counter_read(&memcg->swap) * PAGE_SIZE;
7989 static u64 swap_peak_read(struct cgroup_subsys_state *css,
7992 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
7994 return (u64)memcg->swap.watermark * PAGE_SIZE;
7997 static int swap_high_show(struct seq_file *m, void *v)
7999 return seq_puts_memcg_tunable(m,
8000 READ_ONCE(mem_cgroup_from_seq(m)->swap.high));
8003 static ssize_t swap_high_write(struct kernfs_open_file *of,
8004 char *buf, size_t nbytes, loff_t off)
8006 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
8010 buf = strstrip(buf);
8011 err = page_counter_memparse(buf, "max", &high);
8015 page_counter_set_high(&memcg->swap, high);
8020 static int swap_max_show(struct seq_file *m, void *v)
8022 return seq_puts_memcg_tunable(m,
8023 READ_ONCE(mem_cgroup_from_seq(m)->swap.max));
8026 static ssize_t swap_max_write(struct kernfs_open_file *of,
8027 char *buf, size_t nbytes, loff_t off)
8029 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
8033 buf = strstrip(buf);
8034 err = page_counter_memparse(buf, "max", &max);
8038 xchg(&memcg->swap.max, max);
8043 static int swap_events_show(struct seq_file *m, void *v)
8045 struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
8047 seq_printf(m, "high %lu\n",
8048 atomic_long_read(&memcg->memory_events[MEMCG_SWAP_HIGH]));
8049 seq_printf(m, "max %lu\n",
8050 atomic_long_read(&memcg->memory_events[MEMCG_SWAP_MAX]));
8051 seq_printf(m, "fail %lu\n",
8052 atomic_long_read(&memcg->memory_events[MEMCG_SWAP_FAIL]));
8057 static struct cftype swap_files[] = {
8059 .name = "swap.current",
8060 .flags = CFTYPE_NOT_ON_ROOT,
8061 .read_u64 = swap_current_read,
8064 .name = "swap.high",
8065 .flags = CFTYPE_NOT_ON_ROOT,
8066 .seq_show = swap_high_show,
8067 .write = swap_high_write,
8071 .flags = CFTYPE_NOT_ON_ROOT,
8072 .seq_show = swap_max_show,
8073 .write = swap_max_write,
8076 .name = "swap.peak",
8077 .flags = CFTYPE_NOT_ON_ROOT,
8078 .read_u64 = swap_peak_read,
8081 .name = "swap.events",
8082 .flags = CFTYPE_NOT_ON_ROOT,
8083 .file_offset = offsetof(struct mem_cgroup, swap_events_file),
8084 .seq_show = swap_events_show,
8089 static struct cftype memsw_files[] = {
8091 .name = "memsw.usage_in_bytes",
8092 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE),
8093 .read_u64 = mem_cgroup_read_u64,
8096 .name = "memsw.max_usage_in_bytes",
8097 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE),
8098 .write = mem_cgroup_reset,
8099 .read_u64 = mem_cgroup_read_u64,
8102 .name = "memsw.limit_in_bytes",
8103 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT),
8104 .write = mem_cgroup_write,
8105 .read_u64 = mem_cgroup_read_u64,
8108 .name = "memsw.failcnt",
8109 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT),
8110 .write = mem_cgroup_reset,
8111 .read_u64 = mem_cgroup_read_u64,
8113 { }, /* terminate */
8116 #if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_ZSWAP)
8118 * obj_cgroup_may_zswap - check if this cgroup can zswap
8119 * @objcg: the object cgroup
8121 * Check if the hierarchical zswap limit has been reached.
8123 * This doesn't check for specific headroom, and it is not atomic
8124 * either. But with zswap, the size of the allocation is only known
8125 * once compression has occurred, and this optimistic pre-check avoids
8126 * spending cycles on compression when there is already no room left
8127 * or zswap is disabled altogether somewhere in the hierarchy.
8129 bool obj_cgroup_may_zswap(struct obj_cgroup *objcg)
8131 struct mem_cgroup *memcg, *original_memcg;
8134 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys))
8137 original_memcg = get_mem_cgroup_from_objcg(objcg);
8138 for (memcg = original_memcg; !mem_cgroup_is_root(memcg);
8139 memcg = parent_mem_cgroup(memcg)) {
8140 unsigned long max = READ_ONCE(memcg->zswap_max);
8141 unsigned long pages;
8143 if (max == PAGE_COUNTER_MAX)
8151 * mem_cgroup_flush_stats() ignores small changes. Use
8152 * do_flush_stats() directly to get accurate stats for charging.
8154 do_flush_stats(memcg);
8155 pages = memcg_page_state(memcg, MEMCG_ZSWAP_B) / PAGE_SIZE;
8161 mem_cgroup_put(original_memcg);
8166 * obj_cgroup_charge_zswap - charge compression backend memory
8167 * @objcg: the object cgroup
8168 * @size: size of compressed object
8170 * This forces the charge after obj_cgroup_may_zswap() allowed
8171 * compression and storage in zwap for this cgroup to go ahead.
8173 void obj_cgroup_charge_zswap(struct obj_cgroup *objcg, size_t size)
8175 struct mem_cgroup *memcg;
8177 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys))
8180 VM_WARN_ON_ONCE(!(current->flags & PF_MEMALLOC));
8182 /* PF_MEMALLOC context, charging must succeed */
8183 if (obj_cgroup_charge(objcg, GFP_KERNEL, size))
8187 memcg = obj_cgroup_memcg(objcg);
8188 mod_memcg_state(memcg, MEMCG_ZSWAP_B, size);
8189 mod_memcg_state(memcg, MEMCG_ZSWAPPED, 1);
8194 * obj_cgroup_uncharge_zswap - uncharge compression backend memory
8195 * @objcg: the object cgroup
8196 * @size: size of compressed object
8198 * Uncharges zswap memory on page in.
8200 void obj_cgroup_uncharge_zswap(struct obj_cgroup *objcg, size_t size)
8202 struct mem_cgroup *memcg;
8204 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys))
8207 obj_cgroup_uncharge(objcg, size);
8210 memcg = obj_cgroup_memcg(objcg);
8211 mod_memcg_state(memcg, MEMCG_ZSWAP_B, -size);
8212 mod_memcg_state(memcg, MEMCG_ZSWAPPED, -1);
8216 bool mem_cgroup_zswap_writeback_enabled(struct mem_cgroup *memcg)
8218 /* if zswap is disabled, do not block pages going to the swapping device */
8219 return !is_zswap_enabled() || !memcg || READ_ONCE(memcg->zswap_writeback);
8222 static u64 zswap_current_read(struct cgroup_subsys_state *css,
8225 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
8227 mem_cgroup_flush_stats(memcg);
8228 return memcg_page_state(memcg, MEMCG_ZSWAP_B);
8231 static int zswap_max_show(struct seq_file *m, void *v)
8233 return seq_puts_memcg_tunable(m,
8234 READ_ONCE(mem_cgroup_from_seq(m)->zswap_max));
8237 static ssize_t zswap_max_write(struct kernfs_open_file *of,
8238 char *buf, size_t nbytes, loff_t off)
8240 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
8244 buf = strstrip(buf);
8245 err = page_counter_memparse(buf, "max", &max);
8249 xchg(&memcg->zswap_max, max);
8254 static int zswap_writeback_show(struct seq_file *m, void *v)
8256 struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
8258 seq_printf(m, "%d\n", READ_ONCE(memcg->zswap_writeback));
8262 static ssize_t zswap_writeback_write(struct kernfs_open_file *of,
8263 char *buf, size_t nbytes, loff_t off)
8265 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
8266 int zswap_writeback;
8267 ssize_t parse_ret = kstrtoint(strstrip(buf), 0, &zswap_writeback);
8272 if (zswap_writeback != 0 && zswap_writeback != 1)
8275 WRITE_ONCE(memcg->zswap_writeback, zswap_writeback);
8279 static struct cftype zswap_files[] = {
8281 .name = "zswap.current",
8282 .flags = CFTYPE_NOT_ON_ROOT,
8283 .read_u64 = zswap_current_read,
8286 .name = "zswap.max",
8287 .flags = CFTYPE_NOT_ON_ROOT,
8288 .seq_show = zswap_max_show,
8289 .write = zswap_max_write,
8292 .name = "zswap.writeback",
8293 .seq_show = zswap_writeback_show,
8294 .write = zswap_writeback_write,
8298 #endif /* CONFIG_MEMCG_KMEM && CONFIG_ZSWAP */
8300 static int __init mem_cgroup_swap_init(void)
8302 if (mem_cgroup_disabled())
8305 WARN_ON(cgroup_add_dfl_cftypes(&memory_cgrp_subsys, swap_files));
8306 WARN_ON(cgroup_add_legacy_cftypes(&memory_cgrp_subsys, memsw_files));
8307 #if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_ZSWAP)
8308 WARN_ON(cgroup_add_dfl_cftypes(&memory_cgrp_subsys, zswap_files));
8312 subsys_initcall(mem_cgroup_swap_init);
8314 #endif /* CONFIG_SWAP */