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
)
7976 if (!kstrtobool(s
, &res
) && !res
)
7977 pr_warn_once("The swapaccount=0 commandline option is deprecated "
7978 "in favor of configuring swap control via cgroupfs. "
7979 "Please report your usecase to linux-mm@kvack.org if you "
7980 "depend on this functionality.\n");
7983 __setup("swapaccount=", setup_swap_account
);
7985 static u64
swap_current_read(struct cgroup_subsys_state
*css
,
7988 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
7990 return (u64
)page_counter_read(&memcg
->swap
) * PAGE_SIZE
;
7993 static u64
swap_peak_read(struct cgroup_subsys_state
*css
,
7996 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
7998 return (u64
)memcg
->swap
.watermark
* PAGE_SIZE
;
8001 static int swap_high_show(struct seq_file
*m
, void *v
)
8003 return seq_puts_memcg_tunable(m
,
8004 READ_ONCE(mem_cgroup_from_seq(m
)->swap
.high
));
8007 static ssize_t
swap_high_write(struct kernfs_open_file
*of
,
8008 char *buf
, size_t nbytes
, loff_t off
)
8010 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
8014 buf
= strstrip(buf
);
8015 err
= page_counter_memparse(buf
, "max", &high
);
8019 page_counter_set_high(&memcg
->swap
, high
);
8024 static int swap_max_show(struct seq_file
*m
, void *v
)
8026 return seq_puts_memcg_tunable(m
,
8027 READ_ONCE(mem_cgroup_from_seq(m
)->swap
.max
));
8030 static ssize_t
swap_max_write(struct kernfs_open_file
*of
,
8031 char *buf
, size_t nbytes
, loff_t off
)
8033 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
8037 buf
= strstrip(buf
);
8038 err
= page_counter_memparse(buf
, "max", &max
);
8042 xchg(&memcg
->swap
.max
, max
);
8047 static int swap_events_show(struct seq_file
*m
, void *v
)
8049 struct mem_cgroup
*memcg
= mem_cgroup_from_seq(m
);
8051 seq_printf(m
, "high %lu\n",
8052 atomic_long_read(&memcg
->memory_events
[MEMCG_SWAP_HIGH
]));
8053 seq_printf(m
, "max %lu\n",
8054 atomic_long_read(&memcg
->memory_events
[MEMCG_SWAP_MAX
]));
8055 seq_printf(m
, "fail %lu\n",
8056 atomic_long_read(&memcg
->memory_events
[MEMCG_SWAP_FAIL
]));
8061 static struct cftype swap_files
[] = {
8063 .name
= "swap.current",
8064 .flags
= CFTYPE_NOT_ON_ROOT
,
8065 .read_u64
= swap_current_read
,
8068 .name
= "swap.high",
8069 .flags
= CFTYPE_NOT_ON_ROOT
,
8070 .seq_show
= swap_high_show
,
8071 .write
= swap_high_write
,
8075 .flags
= CFTYPE_NOT_ON_ROOT
,
8076 .seq_show
= swap_max_show
,
8077 .write
= swap_max_write
,
8080 .name
= "swap.peak",
8081 .flags
= CFTYPE_NOT_ON_ROOT
,
8082 .read_u64
= swap_peak_read
,
8085 .name
= "swap.events",
8086 .flags
= CFTYPE_NOT_ON_ROOT
,
8087 .file_offset
= offsetof(struct mem_cgroup
, swap_events_file
),
8088 .seq_show
= swap_events_show
,
8093 static struct cftype memsw_files
[] = {
8095 .name
= "memsw.usage_in_bytes",
8096 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_USAGE
),
8097 .read_u64
= mem_cgroup_read_u64
,
8100 .name
= "memsw.max_usage_in_bytes",
8101 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_MAX_USAGE
),
8102 .write
= mem_cgroup_reset
,
8103 .read_u64
= mem_cgroup_read_u64
,
8106 .name
= "memsw.limit_in_bytes",
8107 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_LIMIT
),
8108 .write
= mem_cgroup_write
,
8109 .read_u64
= mem_cgroup_read_u64
,
8112 .name
= "memsw.failcnt",
8113 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_FAILCNT
),
8114 .write
= mem_cgroup_reset
,
8115 .read_u64
= mem_cgroup_read_u64
,
8117 { }, /* terminate */
8120 #if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_ZSWAP)
8122 * obj_cgroup_may_zswap - check if this cgroup can zswap
8123 * @objcg: the object cgroup
8125 * Check if the hierarchical zswap limit has been reached.
8127 * This doesn't check for specific headroom, and it is not atomic
8128 * either. But with zswap, the size of the allocation is only known
8129 * once compression has occurred, and this optimistic pre-check avoids
8130 * spending cycles on compression when there is already no room left
8131 * or zswap is disabled altogether somewhere in the hierarchy.
8133 bool obj_cgroup_may_zswap(struct obj_cgroup
*objcg
)
8135 struct mem_cgroup
*memcg
, *original_memcg
;
8138 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
))
8141 original_memcg
= get_mem_cgroup_from_objcg(objcg
);
8142 for (memcg
= original_memcg
; !mem_cgroup_is_root(memcg
);
8143 memcg
= parent_mem_cgroup(memcg
)) {
8144 unsigned long max
= READ_ONCE(memcg
->zswap_max
);
8145 unsigned long pages
;
8147 if (max
== PAGE_COUNTER_MAX
)
8155 * mem_cgroup_flush_stats() ignores small changes. Use
8156 * do_flush_stats() directly to get accurate stats for charging.
8158 do_flush_stats(memcg
);
8159 pages
= memcg_page_state(memcg
, MEMCG_ZSWAP_B
) / PAGE_SIZE
;
8165 mem_cgroup_put(original_memcg
);
8170 * obj_cgroup_charge_zswap - charge compression backend memory
8171 * @objcg: the object cgroup
8172 * @size: size of compressed object
8174 * This forces the charge after obj_cgroup_may_zswap() allowed
8175 * compression and storage in zwap for this cgroup to go ahead.
8177 void obj_cgroup_charge_zswap(struct obj_cgroup
*objcg
, size_t size
)
8179 struct mem_cgroup
*memcg
;
8181 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
))
8184 VM_WARN_ON_ONCE(!(current
->flags
& PF_MEMALLOC
));
8186 /* PF_MEMALLOC context, charging must succeed */
8187 if (obj_cgroup_charge(objcg
, GFP_KERNEL
, size
))
8191 memcg
= obj_cgroup_memcg(objcg
);
8192 mod_memcg_state(memcg
, MEMCG_ZSWAP_B
, size
);
8193 mod_memcg_state(memcg
, MEMCG_ZSWAPPED
, 1);
8198 * obj_cgroup_uncharge_zswap - uncharge compression backend memory
8199 * @objcg: the object cgroup
8200 * @size: size of compressed object
8202 * Uncharges zswap memory on page in.
8204 void obj_cgroup_uncharge_zswap(struct obj_cgroup
*objcg
, size_t size
)
8206 struct mem_cgroup
*memcg
;
8208 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
))
8211 obj_cgroup_uncharge(objcg
, size
);
8214 memcg
= obj_cgroup_memcg(objcg
);
8215 mod_memcg_state(memcg
, MEMCG_ZSWAP_B
, -size
);
8216 mod_memcg_state(memcg
, MEMCG_ZSWAPPED
, -1);
8220 bool mem_cgroup_zswap_writeback_enabled(struct mem_cgroup
*memcg
)
8222 /* if zswap is disabled, do not block pages going to the swapping device */
8223 return !is_zswap_enabled() || !memcg
|| READ_ONCE(memcg
->zswap_writeback
);
8226 static u64
zswap_current_read(struct cgroup_subsys_state
*css
,
8229 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
8231 mem_cgroup_flush_stats(memcg
);
8232 return memcg_page_state(memcg
, MEMCG_ZSWAP_B
);
8235 static int zswap_max_show(struct seq_file
*m
, void *v
)
8237 return seq_puts_memcg_tunable(m
,
8238 READ_ONCE(mem_cgroup_from_seq(m
)->zswap_max
));
8241 static ssize_t
zswap_max_write(struct kernfs_open_file
*of
,
8242 char *buf
, size_t nbytes
, loff_t off
)
8244 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
8248 buf
= strstrip(buf
);
8249 err
= page_counter_memparse(buf
, "max", &max
);
8253 xchg(&memcg
->zswap_max
, max
);
8258 static int zswap_writeback_show(struct seq_file
*m
, void *v
)
8260 struct mem_cgroup
*memcg
= mem_cgroup_from_seq(m
);
8262 seq_printf(m
, "%d\n", READ_ONCE(memcg
->zswap_writeback
));
8266 static ssize_t
zswap_writeback_write(struct kernfs_open_file
*of
,
8267 char *buf
, size_t nbytes
, loff_t off
)
8269 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
8270 int zswap_writeback
;
8271 ssize_t parse_ret
= kstrtoint(strstrip(buf
), 0, &zswap_writeback
);
8276 if (zswap_writeback
!= 0 && zswap_writeback
!= 1)
8279 WRITE_ONCE(memcg
->zswap_writeback
, zswap_writeback
);
8283 static struct cftype zswap_files
[] = {
8285 .name
= "zswap.current",
8286 .flags
= CFTYPE_NOT_ON_ROOT
,
8287 .read_u64
= zswap_current_read
,
8290 .name
= "zswap.max",
8291 .flags
= CFTYPE_NOT_ON_ROOT
,
8292 .seq_show
= zswap_max_show
,
8293 .write
= zswap_max_write
,
8296 .name
= "zswap.writeback",
8297 .seq_show
= zswap_writeback_show
,
8298 .write
= zswap_writeback_write
,
8302 #endif /* CONFIG_MEMCG_KMEM && CONFIG_ZSWAP */
8304 static int __init
mem_cgroup_swap_init(void)
8306 if (mem_cgroup_disabled())
8309 WARN_ON(cgroup_add_dfl_cftypes(&memory_cgrp_subsys
, swap_files
));
8310 WARN_ON(cgroup_add_legacy_cftypes(&memory_cgrp_subsys
, memsw_files
));
8311 #if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_ZSWAP)
8312 WARN_ON(cgroup_add_dfl_cftypes(&memory_cgrp_subsys
, zswap_files
));
8316 subsys_initcall(mem_cgroup_swap_init
);
8318 #endif /* CONFIG_SWAP */