ext4: don't pass entire map to check_eofblocks_fl
[linux/fpc-iii.git] / mm / memcontrol.c
blob7a22b41292115f78dc039ebf5e271090dc5a8f9d
1 /* memcontrol.c - Memory Controller
3 * Copyright IBM Corporation, 2007
4 * Author Balbir Singh <balbir@linux.vnet.ibm.com>
6 * Copyright 2007 OpenVZ SWsoft Inc
7 * Author: Pavel Emelianov <xemul@openvz.org>
9 * Memory thresholds
10 * Copyright (C) 2009 Nokia Corporation
11 * Author: Kirill A. Shutemov
13 * This program is free software; you can redistribute it and/or modify
14 * it under the terms of the GNU General Public License as published by
15 * the Free Software Foundation; either version 2 of the License, or
16 * (at your option) any later version.
18 * This program is distributed in the hope that it will be useful,
19 * but WITHOUT ANY WARRANTY; without even the implied warranty of
20 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
21 * GNU General Public License for more details.
24 #include <linux/res_counter.h>
25 #include <linux/memcontrol.h>
26 #include <linux/cgroup.h>
27 #include <linux/mm.h>
28 #include <linux/hugetlb.h>
29 #include <linux/pagemap.h>
30 #include <linux/smp.h>
31 #include <linux/page-flags.h>
32 #include <linux/backing-dev.h>
33 #include <linux/bit_spinlock.h>
34 #include <linux/rcupdate.h>
35 #include <linux/limits.h>
36 #include <linux/mutex.h>
37 #include <linux/rbtree.h>
38 #include <linux/slab.h>
39 #include <linux/swap.h>
40 #include <linux/swapops.h>
41 #include <linux/spinlock.h>
42 #include <linux/eventfd.h>
43 #include <linux/sort.h>
44 #include <linux/fs.h>
45 #include <linux/seq_file.h>
46 #include <linux/vmalloc.h>
47 #include <linux/mm_inline.h>
48 #include <linux/page_cgroup.h>
49 #include <linux/cpu.h>
50 #include <linux/oom.h>
51 #include "internal.h"
53 #include <asm/uaccess.h>
55 #include <trace/events/vmscan.h>
57 struct cgroup_subsys mem_cgroup_subsys __read_mostly;
58 #define MEM_CGROUP_RECLAIM_RETRIES 5
59 struct mem_cgroup *root_mem_cgroup __read_mostly;
61 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
62 /* Turned on only when memory cgroup is enabled && really_do_swap_account = 1 */
63 int do_swap_account __read_mostly;
65 /* for remember boot option*/
66 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP_ENABLED
67 static int really_do_swap_account __initdata = 1;
68 #else
69 static int really_do_swap_account __initdata = 0;
70 #endif
72 #else
73 #define do_swap_account (0)
74 #endif
77 * Per memcg event counter is incremented at every pagein/pageout. This counter
78 * is used for trigger some periodic events. This is straightforward and better
79 * than using jiffies etc. to handle periodic memcg event.
81 * These values will be used as !((event) & ((1 <<(thresh)) - 1))
83 #define THRESHOLDS_EVENTS_THRESH (7) /* once in 128 */
84 #define SOFTLIMIT_EVENTS_THRESH (10) /* once in 1024 */
87 * Statistics for memory cgroup.
89 enum mem_cgroup_stat_index {
91 * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss.
93 MEM_CGROUP_STAT_CACHE, /* # of pages charged as cache */
94 MEM_CGROUP_STAT_RSS, /* # of pages charged as anon rss */
95 MEM_CGROUP_STAT_FILE_MAPPED, /* # of pages charged as file rss */
96 MEM_CGROUP_STAT_PGPGIN_COUNT, /* # of pages paged in */
97 MEM_CGROUP_STAT_PGPGOUT_COUNT, /* # of pages paged out */
98 MEM_CGROUP_STAT_SWAPOUT, /* # of pages, swapped out */
99 MEM_CGROUP_STAT_DATA, /* end of data requires synchronization */
100 /* incremented at every pagein/pageout */
101 MEM_CGROUP_EVENTS = MEM_CGROUP_STAT_DATA,
102 MEM_CGROUP_ON_MOVE, /* someone is moving account between groups */
104 MEM_CGROUP_STAT_NSTATS,
107 struct mem_cgroup_stat_cpu {
108 s64 count[MEM_CGROUP_STAT_NSTATS];
112 * per-zone information in memory controller.
114 struct mem_cgroup_per_zone {
116 * spin_lock to protect the per cgroup LRU
118 struct list_head lists[NR_LRU_LISTS];
119 unsigned long count[NR_LRU_LISTS];
121 struct zone_reclaim_stat reclaim_stat;
122 struct rb_node tree_node; /* RB tree node */
123 unsigned long long usage_in_excess;/* Set to the value by which */
124 /* the soft limit is exceeded*/
125 bool on_tree;
126 struct mem_cgroup *mem; /* Back pointer, we cannot */
127 /* use container_of */
129 /* Macro for accessing counter */
130 #define MEM_CGROUP_ZSTAT(mz, idx) ((mz)->count[(idx)])
132 struct mem_cgroup_per_node {
133 struct mem_cgroup_per_zone zoneinfo[MAX_NR_ZONES];
136 struct mem_cgroup_lru_info {
137 struct mem_cgroup_per_node *nodeinfo[MAX_NUMNODES];
141 * Cgroups above their limits are maintained in a RB-Tree, independent of
142 * their hierarchy representation
145 struct mem_cgroup_tree_per_zone {
146 struct rb_root rb_root;
147 spinlock_t lock;
150 struct mem_cgroup_tree_per_node {
151 struct mem_cgroup_tree_per_zone rb_tree_per_zone[MAX_NR_ZONES];
154 struct mem_cgroup_tree {
155 struct mem_cgroup_tree_per_node *rb_tree_per_node[MAX_NUMNODES];
158 static struct mem_cgroup_tree soft_limit_tree __read_mostly;
160 struct mem_cgroup_threshold {
161 struct eventfd_ctx *eventfd;
162 u64 threshold;
165 /* For threshold */
166 struct mem_cgroup_threshold_ary {
167 /* An array index points to threshold just below usage. */
168 int current_threshold;
169 /* Size of entries[] */
170 unsigned int size;
171 /* Array of thresholds */
172 struct mem_cgroup_threshold entries[0];
175 struct mem_cgroup_thresholds {
176 /* Primary thresholds array */
177 struct mem_cgroup_threshold_ary *primary;
179 * Spare threshold array.
180 * This is needed to make mem_cgroup_unregister_event() "never fail".
181 * It must be able to store at least primary->size - 1 entries.
183 struct mem_cgroup_threshold_ary *spare;
186 /* for OOM */
187 struct mem_cgroup_eventfd_list {
188 struct list_head list;
189 struct eventfd_ctx *eventfd;
192 static void mem_cgroup_threshold(struct mem_cgroup *mem);
193 static void mem_cgroup_oom_notify(struct mem_cgroup *mem);
196 * The memory controller data structure. The memory controller controls both
197 * page cache and RSS per cgroup. We would eventually like to provide
198 * statistics based on the statistics developed by Rik Van Riel for clock-pro,
199 * to help the administrator determine what knobs to tune.
201 * TODO: Add a water mark for the memory controller. Reclaim will begin when
202 * we hit the water mark. May be even add a low water mark, such that
203 * no reclaim occurs from a cgroup at it's low water mark, this is
204 * a feature that will be implemented much later in the future.
206 struct mem_cgroup {
207 struct cgroup_subsys_state css;
209 * the counter to account for memory usage
211 struct res_counter res;
213 * the counter to account for mem+swap usage.
215 struct res_counter memsw;
217 * Per cgroup active and inactive list, similar to the
218 * per zone LRU lists.
220 struct mem_cgroup_lru_info info;
223 protect against reclaim related member.
225 spinlock_t reclaim_param_lock;
228 * While reclaiming in a hierarchy, we cache the last child we
229 * reclaimed from.
231 int last_scanned_child;
233 * Should the accounting and control be hierarchical, per subtree?
235 bool use_hierarchy;
236 atomic_t oom_lock;
237 atomic_t refcnt;
239 unsigned int swappiness;
240 /* OOM-Killer disable */
241 int oom_kill_disable;
243 /* set when res.limit == memsw.limit */
244 bool memsw_is_minimum;
246 /* protect arrays of thresholds */
247 struct mutex thresholds_lock;
249 /* thresholds for memory usage. RCU-protected */
250 struct mem_cgroup_thresholds thresholds;
252 /* thresholds for mem+swap usage. RCU-protected */
253 struct mem_cgroup_thresholds memsw_thresholds;
255 /* For oom notifier event fd */
256 struct list_head oom_notify;
259 * Should we move charges of a task when a task is moved into this
260 * mem_cgroup ? And what type of charges should we move ?
262 unsigned long move_charge_at_immigrate;
264 * percpu counter.
266 struct mem_cgroup_stat_cpu *stat;
268 * used when a cpu is offlined or other synchronizations
269 * See mem_cgroup_read_stat().
271 struct mem_cgroup_stat_cpu nocpu_base;
272 spinlock_t pcp_counter_lock;
275 /* Stuffs for move charges at task migration. */
277 * Types of charges to be moved. "move_charge_at_immitgrate" is treated as a
278 * left-shifted bitmap of these types.
280 enum move_type {
281 MOVE_CHARGE_TYPE_ANON, /* private anonymous page and swap of it */
282 MOVE_CHARGE_TYPE_FILE, /* file page(including tmpfs) and swap of it */
283 NR_MOVE_TYPE,
286 /* "mc" and its members are protected by cgroup_mutex */
287 static struct move_charge_struct {
288 spinlock_t lock; /* for from, to */
289 struct mem_cgroup *from;
290 struct mem_cgroup *to;
291 unsigned long precharge;
292 unsigned long moved_charge;
293 unsigned long moved_swap;
294 struct task_struct *moving_task; /* a task moving charges */
295 struct mm_struct *mm;
296 wait_queue_head_t waitq; /* a waitq for other context */
297 } mc = {
298 .lock = __SPIN_LOCK_UNLOCKED(mc.lock),
299 .waitq = __WAIT_QUEUE_HEAD_INITIALIZER(mc.waitq),
302 static bool move_anon(void)
304 return test_bit(MOVE_CHARGE_TYPE_ANON,
305 &mc.to->move_charge_at_immigrate);
308 static bool move_file(void)
310 return test_bit(MOVE_CHARGE_TYPE_FILE,
311 &mc.to->move_charge_at_immigrate);
315 * Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft
316 * limit reclaim to prevent infinite loops, if they ever occur.
318 #define MEM_CGROUP_MAX_RECLAIM_LOOPS (100)
319 #define MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS (2)
321 enum charge_type {
322 MEM_CGROUP_CHARGE_TYPE_CACHE = 0,
323 MEM_CGROUP_CHARGE_TYPE_MAPPED,
324 MEM_CGROUP_CHARGE_TYPE_SHMEM, /* used by page migration of shmem */
325 MEM_CGROUP_CHARGE_TYPE_FORCE, /* used by force_empty */
326 MEM_CGROUP_CHARGE_TYPE_SWAPOUT, /* for accounting swapcache */
327 MEM_CGROUP_CHARGE_TYPE_DROP, /* a page was unused swap cache */
328 NR_CHARGE_TYPE,
331 /* only for here (for easy reading.) */
332 #define PCGF_CACHE (1UL << PCG_CACHE)
333 #define PCGF_USED (1UL << PCG_USED)
334 #define PCGF_LOCK (1UL << PCG_LOCK)
335 /* Not used, but added here for completeness */
336 #define PCGF_ACCT (1UL << PCG_ACCT)
338 /* for encoding cft->private value on file */
339 #define _MEM (0)
340 #define _MEMSWAP (1)
341 #define _OOM_TYPE (2)
342 #define MEMFILE_PRIVATE(x, val) (((x) << 16) | (val))
343 #define MEMFILE_TYPE(val) (((val) >> 16) & 0xffff)
344 #define MEMFILE_ATTR(val) ((val) & 0xffff)
345 /* Used for OOM nofiier */
346 #define OOM_CONTROL (0)
349 * Reclaim flags for mem_cgroup_hierarchical_reclaim
351 #define MEM_CGROUP_RECLAIM_NOSWAP_BIT 0x0
352 #define MEM_CGROUP_RECLAIM_NOSWAP (1 << MEM_CGROUP_RECLAIM_NOSWAP_BIT)
353 #define MEM_CGROUP_RECLAIM_SHRINK_BIT 0x1
354 #define MEM_CGROUP_RECLAIM_SHRINK (1 << MEM_CGROUP_RECLAIM_SHRINK_BIT)
355 #define MEM_CGROUP_RECLAIM_SOFT_BIT 0x2
356 #define MEM_CGROUP_RECLAIM_SOFT (1 << MEM_CGROUP_RECLAIM_SOFT_BIT)
358 static void mem_cgroup_get(struct mem_cgroup *mem);
359 static void mem_cgroup_put(struct mem_cgroup *mem);
360 static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem);
361 static void drain_all_stock_async(void);
363 static struct mem_cgroup_per_zone *
364 mem_cgroup_zoneinfo(struct mem_cgroup *mem, int nid, int zid)
366 return &mem->info.nodeinfo[nid]->zoneinfo[zid];
369 struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *mem)
371 return &mem->css;
374 static struct mem_cgroup_per_zone *
375 page_cgroup_zoneinfo(struct page_cgroup *pc)
377 struct mem_cgroup *mem = pc->mem_cgroup;
378 int nid = page_cgroup_nid(pc);
379 int zid = page_cgroup_zid(pc);
381 if (!mem)
382 return NULL;
384 return mem_cgroup_zoneinfo(mem, nid, zid);
387 static struct mem_cgroup_tree_per_zone *
388 soft_limit_tree_node_zone(int nid, int zid)
390 return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid];
393 static struct mem_cgroup_tree_per_zone *
394 soft_limit_tree_from_page(struct page *page)
396 int nid = page_to_nid(page);
397 int zid = page_zonenum(page);
399 return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid];
402 static void
403 __mem_cgroup_insert_exceeded(struct mem_cgroup *mem,
404 struct mem_cgroup_per_zone *mz,
405 struct mem_cgroup_tree_per_zone *mctz,
406 unsigned long long new_usage_in_excess)
408 struct rb_node **p = &mctz->rb_root.rb_node;
409 struct rb_node *parent = NULL;
410 struct mem_cgroup_per_zone *mz_node;
412 if (mz->on_tree)
413 return;
415 mz->usage_in_excess = new_usage_in_excess;
416 if (!mz->usage_in_excess)
417 return;
418 while (*p) {
419 parent = *p;
420 mz_node = rb_entry(parent, struct mem_cgroup_per_zone,
421 tree_node);
422 if (mz->usage_in_excess < mz_node->usage_in_excess)
423 p = &(*p)->rb_left;
425 * We can't avoid mem cgroups that are over their soft
426 * limit by the same amount
428 else if (mz->usage_in_excess >= mz_node->usage_in_excess)
429 p = &(*p)->rb_right;
431 rb_link_node(&mz->tree_node, parent, p);
432 rb_insert_color(&mz->tree_node, &mctz->rb_root);
433 mz->on_tree = true;
436 static void
437 __mem_cgroup_remove_exceeded(struct mem_cgroup *mem,
438 struct mem_cgroup_per_zone *mz,
439 struct mem_cgroup_tree_per_zone *mctz)
441 if (!mz->on_tree)
442 return;
443 rb_erase(&mz->tree_node, &mctz->rb_root);
444 mz->on_tree = false;
447 static void
448 mem_cgroup_remove_exceeded(struct mem_cgroup *mem,
449 struct mem_cgroup_per_zone *mz,
450 struct mem_cgroup_tree_per_zone *mctz)
452 spin_lock(&mctz->lock);
453 __mem_cgroup_remove_exceeded(mem, mz, mctz);
454 spin_unlock(&mctz->lock);
458 static void mem_cgroup_update_tree(struct mem_cgroup *mem, struct page *page)
460 unsigned long long excess;
461 struct mem_cgroup_per_zone *mz;
462 struct mem_cgroup_tree_per_zone *mctz;
463 int nid = page_to_nid(page);
464 int zid = page_zonenum(page);
465 mctz = soft_limit_tree_from_page(page);
468 * Necessary to update all ancestors when hierarchy is used.
469 * because their event counter is not touched.
471 for (; mem; mem = parent_mem_cgroup(mem)) {
472 mz = mem_cgroup_zoneinfo(mem, nid, zid);
473 excess = res_counter_soft_limit_excess(&mem->res);
475 * We have to update the tree if mz is on RB-tree or
476 * mem is over its softlimit.
478 if (excess || mz->on_tree) {
479 spin_lock(&mctz->lock);
480 /* if on-tree, remove it */
481 if (mz->on_tree)
482 __mem_cgroup_remove_exceeded(mem, mz, mctz);
484 * Insert again. mz->usage_in_excess will be updated.
485 * If excess is 0, no tree ops.
487 __mem_cgroup_insert_exceeded(mem, mz, mctz, excess);
488 spin_unlock(&mctz->lock);
493 static void mem_cgroup_remove_from_trees(struct mem_cgroup *mem)
495 int node, zone;
496 struct mem_cgroup_per_zone *mz;
497 struct mem_cgroup_tree_per_zone *mctz;
499 for_each_node_state(node, N_POSSIBLE) {
500 for (zone = 0; zone < MAX_NR_ZONES; zone++) {
501 mz = mem_cgroup_zoneinfo(mem, node, zone);
502 mctz = soft_limit_tree_node_zone(node, zone);
503 mem_cgroup_remove_exceeded(mem, mz, mctz);
508 static inline unsigned long mem_cgroup_get_excess(struct mem_cgroup *mem)
510 return res_counter_soft_limit_excess(&mem->res) >> PAGE_SHIFT;
513 static struct mem_cgroup_per_zone *
514 __mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
516 struct rb_node *rightmost = NULL;
517 struct mem_cgroup_per_zone *mz;
519 retry:
520 mz = NULL;
521 rightmost = rb_last(&mctz->rb_root);
522 if (!rightmost)
523 goto done; /* Nothing to reclaim from */
525 mz = rb_entry(rightmost, struct mem_cgroup_per_zone, tree_node);
527 * Remove the node now but someone else can add it back,
528 * we will to add it back at the end of reclaim to its correct
529 * position in the tree.
531 __mem_cgroup_remove_exceeded(mz->mem, mz, mctz);
532 if (!res_counter_soft_limit_excess(&mz->mem->res) ||
533 !css_tryget(&mz->mem->css))
534 goto retry;
535 done:
536 return mz;
539 static struct mem_cgroup_per_zone *
540 mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
542 struct mem_cgroup_per_zone *mz;
544 spin_lock(&mctz->lock);
545 mz = __mem_cgroup_largest_soft_limit_node(mctz);
546 spin_unlock(&mctz->lock);
547 return mz;
551 * Implementation Note: reading percpu statistics for memcg.
553 * Both of vmstat[] and percpu_counter has threshold and do periodic
554 * synchronization to implement "quick" read. There are trade-off between
555 * reading cost and precision of value. Then, we may have a chance to implement
556 * a periodic synchronizion of counter in memcg's counter.
558 * But this _read() function is used for user interface now. The user accounts
559 * memory usage by memory cgroup and he _always_ requires exact value because
560 * he accounts memory. Even if we provide quick-and-fuzzy read, we always
561 * have to visit all online cpus and make sum. So, for now, unnecessary
562 * synchronization is not implemented. (just implemented for cpu hotplug)
564 * If there are kernel internal actions which can make use of some not-exact
565 * value, and reading all cpu value can be performance bottleneck in some
566 * common workload, threashold and synchonization as vmstat[] should be
567 * implemented.
569 static s64 mem_cgroup_read_stat(struct mem_cgroup *mem,
570 enum mem_cgroup_stat_index idx)
572 int cpu;
573 s64 val = 0;
575 get_online_cpus();
576 for_each_online_cpu(cpu)
577 val += per_cpu(mem->stat->count[idx], cpu);
578 #ifdef CONFIG_HOTPLUG_CPU
579 spin_lock(&mem->pcp_counter_lock);
580 val += mem->nocpu_base.count[idx];
581 spin_unlock(&mem->pcp_counter_lock);
582 #endif
583 put_online_cpus();
584 return val;
587 static s64 mem_cgroup_local_usage(struct mem_cgroup *mem)
589 s64 ret;
591 ret = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_RSS);
592 ret += mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_CACHE);
593 return ret;
596 static void mem_cgroup_swap_statistics(struct mem_cgroup *mem,
597 bool charge)
599 int val = (charge) ? 1 : -1;
600 this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_SWAPOUT], val);
603 static void mem_cgroup_charge_statistics(struct mem_cgroup *mem,
604 struct page_cgroup *pc,
605 bool charge)
607 int val = (charge) ? 1 : -1;
609 preempt_disable();
611 if (PageCgroupCache(pc))
612 __this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_CACHE], val);
613 else
614 __this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_RSS], val);
616 if (charge)
617 __this_cpu_inc(mem->stat->count[MEM_CGROUP_STAT_PGPGIN_COUNT]);
618 else
619 __this_cpu_inc(mem->stat->count[MEM_CGROUP_STAT_PGPGOUT_COUNT]);
620 __this_cpu_inc(mem->stat->count[MEM_CGROUP_EVENTS]);
622 preempt_enable();
625 static unsigned long mem_cgroup_get_local_zonestat(struct mem_cgroup *mem,
626 enum lru_list idx)
628 int nid, zid;
629 struct mem_cgroup_per_zone *mz;
630 u64 total = 0;
632 for_each_online_node(nid)
633 for (zid = 0; zid < MAX_NR_ZONES; zid++) {
634 mz = mem_cgroup_zoneinfo(mem, nid, zid);
635 total += MEM_CGROUP_ZSTAT(mz, idx);
637 return total;
640 static bool __memcg_event_check(struct mem_cgroup *mem, int event_mask_shift)
642 s64 val;
644 val = this_cpu_read(mem->stat->count[MEM_CGROUP_EVENTS]);
646 return !(val & ((1 << event_mask_shift) - 1));
650 * Check events in order.
653 static void memcg_check_events(struct mem_cgroup *mem, struct page *page)
655 /* threshold event is triggered in finer grain than soft limit */
656 if (unlikely(__memcg_event_check(mem, THRESHOLDS_EVENTS_THRESH))) {
657 mem_cgroup_threshold(mem);
658 if (unlikely(__memcg_event_check(mem, SOFTLIMIT_EVENTS_THRESH)))
659 mem_cgroup_update_tree(mem, page);
663 static struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont)
665 return container_of(cgroup_subsys_state(cont,
666 mem_cgroup_subsys_id), struct mem_cgroup,
667 css);
670 struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
673 * mm_update_next_owner() may clear mm->owner to NULL
674 * if it races with swapoff, page migration, etc.
675 * So this can be called with p == NULL.
677 if (unlikely(!p))
678 return NULL;
680 return container_of(task_subsys_state(p, mem_cgroup_subsys_id),
681 struct mem_cgroup, css);
684 static struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm)
686 struct mem_cgroup *mem = NULL;
688 if (!mm)
689 return NULL;
691 * Because we have no locks, mm->owner's may be being moved to other
692 * cgroup. We use css_tryget() here even if this looks
693 * pessimistic (rather than adding locks here).
695 rcu_read_lock();
696 do {
697 mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
698 if (unlikely(!mem))
699 break;
700 } while (!css_tryget(&mem->css));
701 rcu_read_unlock();
702 return mem;
705 /* The caller has to guarantee "mem" exists before calling this */
706 static struct mem_cgroup *mem_cgroup_start_loop(struct mem_cgroup *mem)
708 struct cgroup_subsys_state *css;
709 int found;
711 if (!mem) /* ROOT cgroup has the smallest ID */
712 return root_mem_cgroup; /*css_put/get against root is ignored*/
713 if (!mem->use_hierarchy) {
714 if (css_tryget(&mem->css))
715 return mem;
716 return NULL;
718 rcu_read_lock();
720 * searching a memory cgroup which has the smallest ID under given
721 * ROOT cgroup. (ID >= 1)
723 css = css_get_next(&mem_cgroup_subsys, 1, &mem->css, &found);
724 if (css && css_tryget(css))
725 mem = container_of(css, struct mem_cgroup, css);
726 else
727 mem = NULL;
728 rcu_read_unlock();
729 return mem;
732 static struct mem_cgroup *mem_cgroup_get_next(struct mem_cgroup *iter,
733 struct mem_cgroup *root,
734 bool cond)
736 int nextid = css_id(&iter->css) + 1;
737 int found;
738 int hierarchy_used;
739 struct cgroup_subsys_state *css;
741 hierarchy_used = iter->use_hierarchy;
743 css_put(&iter->css);
744 /* If no ROOT, walk all, ignore hierarchy */
745 if (!cond || (root && !hierarchy_used))
746 return NULL;
748 if (!root)
749 root = root_mem_cgroup;
751 do {
752 iter = NULL;
753 rcu_read_lock();
755 css = css_get_next(&mem_cgroup_subsys, nextid,
756 &root->css, &found);
757 if (css && css_tryget(css))
758 iter = container_of(css, struct mem_cgroup, css);
759 rcu_read_unlock();
760 /* If css is NULL, no more cgroups will be found */
761 nextid = found + 1;
762 } while (css && !iter);
764 return iter;
767 * for_eacn_mem_cgroup_tree() for visiting all cgroup under tree. Please
768 * be careful that "break" loop is not allowed. We have reference count.
769 * Instead of that modify "cond" to be false and "continue" to exit the loop.
771 #define for_each_mem_cgroup_tree_cond(iter, root, cond) \
772 for (iter = mem_cgroup_start_loop(root);\
773 iter != NULL;\
774 iter = mem_cgroup_get_next(iter, root, cond))
776 #define for_each_mem_cgroup_tree(iter, root) \
777 for_each_mem_cgroup_tree_cond(iter, root, true)
779 #define for_each_mem_cgroup_all(iter) \
780 for_each_mem_cgroup_tree_cond(iter, NULL, true)
783 static inline bool mem_cgroup_is_root(struct mem_cgroup *mem)
785 return (mem == root_mem_cgroup);
789 * Following LRU functions are allowed to be used without PCG_LOCK.
790 * Operations are called by routine of global LRU independently from memcg.
791 * What we have to take care of here is validness of pc->mem_cgroup.
793 * Changes to pc->mem_cgroup happens when
794 * 1. charge
795 * 2. moving account
796 * In typical case, "charge" is done before add-to-lru. Exception is SwapCache.
797 * It is added to LRU before charge.
798 * If PCG_USED bit is not set, page_cgroup is not added to this private LRU.
799 * When moving account, the page is not on LRU. It's isolated.
802 void mem_cgroup_del_lru_list(struct page *page, enum lru_list lru)
804 struct page_cgroup *pc;
805 struct mem_cgroup_per_zone *mz;
807 if (mem_cgroup_disabled())
808 return;
809 pc = lookup_page_cgroup(page);
810 /* can happen while we handle swapcache. */
811 if (!TestClearPageCgroupAcctLRU(pc))
812 return;
813 VM_BUG_ON(!pc->mem_cgroup);
815 * We don't check PCG_USED bit. It's cleared when the "page" is finally
816 * removed from global LRU.
818 mz = page_cgroup_zoneinfo(pc);
819 MEM_CGROUP_ZSTAT(mz, lru) -= 1;
820 if (mem_cgroup_is_root(pc->mem_cgroup))
821 return;
822 VM_BUG_ON(list_empty(&pc->lru));
823 list_del_init(&pc->lru);
824 return;
827 void mem_cgroup_del_lru(struct page *page)
829 mem_cgroup_del_lru_list(page, page_lru(page));
832 void mem_cgroup_rotate_lru_list(struct page *page, enum lru_list lru)
834 struct mem_cgroup_per_zone *mz;
835 struct page_cgroup *pc;
837 if (mem_cgroup_disabled())
838 return;
840 pc = lookup_page_cgroup(page);
842 * Used bit is set without atomic ops but after smp_wmb().
843 * For making pc->mem_cgroup visible, insert smp_rmb() here.
845 smp_rmb();
846 /* unused or root page is not rotated. */
847 if (!PageCgroupUsed(pc) || mem_cgroup_is_root(pc->mem_cgroup))
848 return;
849 mz = page_cgroup_zoneinfo(pc);
850 list_move(&pc->lru, &mz->lists[lru]);
853 void mem_cgroup_add_lru_list(struct page *page, enum lru_list lru)
855 struct page_cgroup *pc;
856 struct mem_cgroup_per_zone *mz;
858 if (mem_cgroup_disabled())
859 return;
860 pc = lookup_page_cgroup(page);
861 VM_BUG_ON(PageCgroupAcctLRU(pc));
863 * Used bit is set without atomic ops but after smp_wmb().
864 * For making pc->mem_cgroup visible, insert smp_rmb() here.
866 smp_rmb();
867 if (!PageCgroupUsed(pc))
868 return;
870 mz = page_cgroup_zoneinfo(pc);
871 MEM_CGROUP_ZSTAT(mz, lru) += 1;
872 SetPageCgroupAcctLRU(pc);
873 if (mem_cgroup_is_root(pc->mem_cgroup))
874 return;
875 list_add(&pc->lru, &mz->lists[lru]);
879 * At handling SwapCache, pc->mem_cgroup may be changed while it's linked to
880 * lru because the page may.be reused after it's fully uncharged (because of
881 * SwapCache behavior).To handle that, unlink page_cgroup from LRU when charge
882 * it again. This function is only used to charge SwapCache. It's done under
883 * lock_page and expected that zone->lru_lock is never held.
885 static void mem_cgroup_lru_del_before_commit_swapcache(struct page *page)
887 unsigned long flags;
888 struct zone *zone = page_zone(page);
889 struct page_cgroup *pc = lookup_page_cgroup(page);
891 spin_lock_irqsave(&zone->lru_lock, flags);
893 * Forget old LRU when this page_cgroup is *not* used. This Used bit
894 * is guarded by lock_page() because the page is SwapCache.
896 if (!PageCgroupUsed(pc))
897 mem_cgroup_del_lru_list(page, page_lru(page));
898 spin_unlock_irqrestore(&zone->lru_lock, flags);
901 static void mem_cgroup_lru_add_after_commit_swapcache(struct page *page)
903 unsigned long flags;
904 struct zone *zone = page_zone(page);
905 struct page_cgroup *pc = lookup_page_cgroup(page);
907 spin_lock_irqsave(&zone->lru_lock, flags);
908 /* link when the page is linked to LRU but page_cgroup isn't */
909 if (PageLRU(page) && !PageCgroupAcctLRU(pc))
910 mem_cgroup_add_lru_list(page, page_lru(page));
911 spin_unlock_irqrestore(&zone->lru_lock, flags);
915 void mem_cgroup_move_lists(struct page *page,
916 enum lru_list from, enum lru_list to)
918 if (mem_cgroup_disabled())
919 return;
920 mem_cgroup_del_lru_list(page, from);
921 mem_cgroup_add_lru_list(page, to);
924 int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem)
926 int ret;
927 struct mem_cgroup *curr = NULL;
928 struct task_struct *p;
930 p = find_lock_task_mm(task);
931 if (!p)
932 return 0;
933 curr = try_get_mem_cgroup_from_mm(p->mm);
934 task_unlock(p);
935 if (!curr)
936 return 0;
938 * We should check use_hierarchy of "mem" not "curr". Because checking
939 * use_hierarchy of "curr" here make this function true if hierarchy is
940 * enabled in "curr" and "curr" is a child of "mem" in *cgroup*
941 * hierarchy(even if use_hierarchy is disabled in "mem").
943 if (mem->use_hierarchy)
944 ret = css_is_ancestor(&curr->css, &mem->css);
945 else
946 ret = (curr == mem);
947 css_put(&curr->css);
948 return ret;
951 static int calc_inactive_ratio(struct mem_cgroup *memcg, unsigned long *present_pages)
953 unsigned long active;
954 unsigned long inactive;
955 unsigned long gb;
956 unsigned long inactive_ratio;
958 inactive = mem_cgroup_get_local_zonestat(memcg, LRU_INACTIVE_ANON);
959 active = mem_cgroup_get_local_zonestat(memcg, LRU_ACTIVE_ANON);
961 gb = (inactive + active) >> (30 - PAGE_SHIFT);
962 if (gb)
963 inactive_ratio = int_sqrt(10 * gb);
964 else
965 inactive_ratio = 1;
967 if (present_pages) {
968 present_pages[0] = inactive;
969 present_pages[1] = active;
972 return inactive_ratio;
975 int mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg)
977 unsigned long active;
978 unsigned long inactive;
979 unsigned long present_pages[2];
980 unsigned long inactive_ratio;
982 inactive_ratio = calc_inactive_ratio(memcg, present_pages);
984 inactive = present_pages[0];
985 active = present_pages[1];
987 if (inactive * inactive_ratio < active)
988 return 1;
990 return 0;
993 int mem_cgroup_inactive_file_is_low(struct mem_cgroup *memcg)
995 unsigned long active;
996 unsigned long inactive;
998 inactive = mem_cgroup_get_local_zonestat(memcg, LRU_INACTIVE_FILE);
999 active = mem_cgroup_get_local_zonestat(memcg, LRU_ACTIVE_FILE);
1001 return (active > inactive);
1004 unsigned long mem_cgroup_zone_nr_pages(struct mem_cgroup *memcg,
1005 struct zone *zone,
1006 enum lru_list lru)
1008 int nid = zone_to_nid(zone);
1009 int zid = zone_idx(zone);
1010 struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid);
1012 return MEM_CGROUP_ZSTAT(mz, lru);
1015 struct zone_reclaim_stat *mem_cgroup_get_reclaim_stat(struct mem_cgroup *memcg,
1016 struct zone *zone)
1018 int nid = zone_to_nid(zone);
1019 int zid = zone_idx(zone);
1020 struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid);
1022 return &mz->reclaim_stat;
1025 struct zone_reclaim_stat *
1026 mem_cgroup_get_reclaim_stat_from_page(struct page *page)
1028 struct page_cgroup *pc;
1029 struct mem_cgroup_per_zone *mz;
1031 if (mem_cgroup_disabled())
1032 return NULL;
1034 pc = lookup_page_cgroup(page);
1036 * Used bit is set without atomic ops but after smp_wmb().
1037 * For making pc->mem_cgroup visible, insert smp_rmb() here.
1039 smp_rmb();
1040 if (!PageCgroupUsed(pc))
1041 return NULL;
1043 mz = page_cgroup_zoneinfo(pc);
1044 if (!mz)
1045 return NULL;
1047 return &mz->reclaim_stat;
1050 unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
1051 struct list_head *dst,
1052 unsigned long *scanned, int order,
1053 int mode, struct zone *z,
1054 struct mem_cgroup *mem_cont,
1055 int active, int file)
1057 unsigned long nr_taken = 0;
1058 struct page *page;
1059 unsigned long scan;
1060 LIST_HEAD(pc_list);
1061 struct list_head *src;
1062 struct page_cgroup *pc, *tmp;
1063 int nid = zone_to_nid(z);
1064 int zid = zone_idx(z);
1065 struct mem_cgroup_per_zone *mz;
1066 int lru = LRU_FILE * file + active;
1067 int ret;
1069 BUG_ON(!mem_cont);
1070 mz = mem_cgroup_zoneinfo(mem_cont, nid, zid);
1071 src = &mz->lists[lru];
1073 scan = 0;
1074 list_for_each_entry_safe_reverse(pc, tmp, src, lru) {
1075 if (scan >= nr_to_scan)
1076 break;
1078 page = pc->page;
1079 if (unlikely(!PageCgroupUsed(pc)))
1080 continue;
1081 if (unlikely(!PageLRU(page)))
1082 continue;
1084 scan++;
1085 ret = __isolate_lru_page(page, mode, file);
1086 switch (ret) {
1087 case 0:
1088 list_move(&page->lru, dst);
1089 mem_cgroup_del_lru(page);
1090 nr_taken++;
1091 break;
1092 case -EBUSY:
1093 /* we don't affect global LRU but rotate in our LRU */
1094 mem_cgroup_rotate_lru_list(page, page_lru(page));
1095 break;
1096 default:
1097 break;
1101 *scanned = scan;
1103 trace_mm_vmscan_memcg_isolate(0, nr_to_scan, scan, nr_taken,
1104 0, 0, 0, mode);
1106 return nr_taken;
1109 #define mem_cgroup_from_res_counter(counter, member) \
1110 container_of(counter, struct mem_cgroup, member)
1112 static bool mem_cgroup_check_under_limit(struct mem_cgroup *mem)
1114 if (do_swap_account) {
1115 if (res_counter_check_under_limit(&mem->res) &&
1116 res_counter_check_under_limit(&mem->memsw))
1117 return true;
1118 } else
1119 if (res_counter_check_under_limit(&mem->res))
1120 return true;
1121 return false;
1124 static unsigned int get_swappiness(struct mem_cgroup *memcg)
1126 struct cgroup *cgrp = memcg->css.cgroup;
1127 unsigned int swappiness;
1129 /* root ? */
1130 if (cgrp->parent == NULL)
1131 return vm_swappiness;
1133 spin_lock(&memcg->reclaim_param_lock);
1134 swappiness = memcg->swappiness;
1135 spin_unlock(&memcg->reclaim_param_lock);
1137 return swappiness;
1140 static void mem_cgroup_start_move(struct mem_cgroup *mem)
1142 int cpu;
1144 get_online_cpus();
1145 spin_lock(&mem->pcp_counter_lock);
1146 for_each_online_cpu(cpu)
1147 per_cpu(mem->stat->count[MEM_CGROUP_ON_MOVE], cpu) += 1;
1148 mem->nocpu_base.count[MEM_CGROUP_ON_MOVE] += 1;
1149 spin_unlock(&mem->pcp_counter_lock);
1150 put_online_cpus();
1152 synchronize_rcu();
1155 static void mem_cgroup_end_move(struct mem_cgroup *mem)
1157 int cpu;
1159 if (!mem)
1160 return;
1161 get_online_cpus();
1162 spin_lock(&mem->pcp_counter_lock);
1163 for_each_online_cpu(cpu)
1164 per_cpu(mem->stat->count[MEM_CGROUP_ON_MOVE], cpu) -= 1;
1165 mem->nocpu_base.count[MEM_CGROUP_ON_MOVE] -= 1;
1166 spin_unlock(&mem->pcp_counter_lock);
1167 put_online_cpus();
1170 * 2 routines for checking "mem" is under move_account() or not.
1172 * mem_cgroup_stealed() - checking a cgroup is mc.from or not. This is used
1173 * for avoiding race in accounting. If true,
1174 * pc->mem_cgroup may be overwritten.
1176 * mem_cgroup_under_move() - checking a cgroup is mc.from or mc.to or
1177 * under hierarchy of moving cgroups. This is for
1178 * waiting at hith-memory prressure caused by "move".
1181 static bool mem_cgroup_stealed(struct mem_cgroup *mem)
1183 VM_BUG_ON(!rcu_read_lock_held());
1184 return this_cpu_read(mem->stat->count[MEM_CGROUP_ON_MOVE]) > 0;
1187 static bool mem_cgroup_under_move(struct mem_cgroup *mem)
1189 struct mem_cgroup *from;
1190 struct mem_cgroup *to;
1191 bool ret = false;
1193 * Unlike task_move routines, we access mc.to, mc.from not under
1194 * mutual exclusion by cgroup_mutex. Here, we take spinlock instead.
1196 spin_lock(&mc.lock);
1197 from = mc.from;
1198 to = mc.to;
1199 if (!from)
1200 goto unlock;
1201 if (from == mem || to == mem
1202 || (mem->use_hierarchy && css_is_ancestor(&from->css, &mem->css))
1203 || (mem->use_hierarchy && css_is_ancestor(&to->css, &mem->css)))
1204 ret = true;
1205 unlock:
1206 spin_unlock(&mc.lock);
1207 return ret;
1210 static bool mem_cgroup_wait_acct_move(struct mem_cgroup *mem)
1212 if (mc.moving_task && current != mc.moving_task) {
1213 if (mem_cgroup_under_move(mem)) {
1214 DEFINE_WAIT(wait);
1215 prepare_to_wait(&mc.waitq, &wait, TASK_INTERRUPTIBLE);
1216 /* moving charge context might have finished. */
1217 if (mc.moving_task)
1218 schedule();
1219 finish_wait(&mc.waitq, &wait);
1220 return true;
1223 return false;
1227 * mem_cgroup_print_oom_info: Called from OOM with tasklist_lock held in read mode.
1228 * @memcg: The memory cgroup that went over limit
1229 * @p: Task that is going to be killed
1231 * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is
1232 * enabled
1234 void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
1236 struct cgroup *task_cgrp;
1237 struct cgroup *mem_cgrp;
1239 * Need a buffer in BSS, can't rely on allocations. The code relies
1240 * on the assumption that OOM is serialized for memory controller.
1241 * If this assumption is broken, revisit this code.
1243 static char memcg_name[PATH_MAX];
1244 int ret;
1246 if (!memcg || !p)
1247 return;
1250 rcu_read_lock();
1252 mem_cgrp = memcg->css.cgroup;
1253 task_cgrp = task_cgroup(p, mem_cgroup_subsys_id);
1255 ret = cgroup_path(task_cgrp, memcg_name, PATH_MAX);
1256 if (ret < 0) {
1258 * Unfortunately, we are unable to convert to a useful name
1259 * But we'll still print out the usage information
1261 rcu_read_unlock();
1262 goto done;
1264 rcu_read_unlock();
1266 printk(KERN_INFO "Task in %s killed", memcg_name);
1268 rcu_read_lock();
1269 ret = cgroup_path(mem_cgrp, memcg_name, PATH_MAX);
1270 if (ret < 0) {
1271 rcu_read_unlock();
1272 goto done;
1274 rcu_read_unlock();
1277 * Continues from above, so we don't need an KERN_ level
1279 printk(KERN_CONT " as a result of limit of %s\n", memcg_name);
1280 done:
1282 printk(KERN_INFO "memory: usage %llukB, limit %llukB, failcnt %llu\n",
1283 res_counter_read_u64(&memcg->res, RES_USAGE) >> 10,
1284 res_counter_read_u64(&memcg->res, RES_LIMIT) >> 10,
1285 res_counter_read_u64(&memcg->res, RES_FAILCNT));
1286 printk(KERN_INFO "memory+swap: usage %llukB, limit %llukB, "
1287 "failcnt %llu\n",
1288 res_counter_read_u64(&memcg->memsw, RES_USAGE) >> 10,
1289 res_counter_read_u64(&memcg->memsw, RES_LIMIT) >> 10,
1290 res_counter_read_u64(&memcg->memsw, RES_FAILCNT));
1294 * This function returns the number of memcg under hierarchy tree. Returns
1295 * 1(self count) if no children.
1297 static int mem_cgroup_count_children(struct mem_cgroup *mem)
1299 int num = 0;
1300 struct mem_cgroup *iter;
1302 for_each_mem_cgroup_tree(iter, mem)
1303 num++;
1304 return num;
1308 * Return the memory (and swap, if configured) limit for a memcg.
1310 u64 mem_cgroup_get_limit(struct mem_cgroup *memcg)
1312 u64 limit;
1313 u64 memsw;
1315 limit = res_counter_read_u64(&memcg->res, RES_LIMIT) +
1316 total_swap_pages;
1317 memsw = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
1319 * If memsw is finite and limits the amount of swap space available
1320 * to this memcg, return that limit.
1322 return min(limit, memsw);
1326 * Visit the first child (need not be the first child as per the ordering
1327 * of the cgroup list, since we track last_scanned_child) of @mem and use
1328 * that to reclaim free pages from.
1330 static struct mem_cgroup *
1331 mem_cgroup_select_victim(struct mem_cgroup *root_mem)
1333 struct mem_cgroup *ret = NULL;
1334 struct cgroup_subsys_state *css;
1335 int nextid, found;
1337 if (!root_mem->use_hierarchy) {
1338 css_get(&root_mem->css);
1339 ret = root_mem;
1342 while (!ret) {
1343 rcu_read_lock();
1344 nextid = root_mem->last_scanned_child + 1;
1345 css = css_get_next(&mem_cgroup_subsys, nextid, &root_mem->css,
1346 &found);
1347 if (css && css_tryget(css))
1348 ret = container_of(css, struct mem_cgroup, css);
1350 rcu_read_unlock();
1351 /* Updates scanning parameter */
1352 spin_lock(&root_mem->reclaim_param_lock);
1353 if (!css) {
1354 /* this means start scan from ID:1 */
1355 root_mem->last_scanned_child = 0;
1356 } else
1357 root_mem->last_scanned_child = found;
1358 spin_unlock(&root_mem->reclaim_param_lock);
1361 return ret;
1365 * Scan the hierarchy if needed to reclaim memory. We remember the last child
1366 * we reclaimed from, so that we don't end up penalizing one child extensively
1367 * based on its position in the children list.
1369 * root_mem is the original ancestor that we've been reclaim from.
1371 * We give up and return to the caller when we visit root_mem twice.
1372 * (other groups can be removed while we're walking....)
1374 * If shrink==true, for avoiding to free too much, this returns immedieately.
1376 static int mem_cgroup_hierarchical_reclaim(struct mem_cgroup *root_mem,
1377 struct zone *zone,
1378 gfp_t gfp_mask,
1379 unsigned long reclaim_options)
1381 struct mem_cgroup *victim;
1382 int ret, total = 0;
1383 int loop = 0;
1384 bool noswap = reclaim_options & MEM_CGROUP_RECLAIM_NOSWAP;
1385 bool shrink = reclaim_options & MEM_CGROUP_RECLAIM_SHRINK;
1386 bool check_soft = reclaim_options & MEM_CGROUP_RECLAIM_SOFT;
1387 unsigned long excess = mem_cgroup_get_excess(root_mem);
1389 /* If memsw_is_minimum==1, swap-out is of-no-use. */
1390 if (root_mem->memsw_is_minimum)
1391 noswap = true;
1393 while (1) {
1394 victim = mem_cgroup_select_victim(root_mem);
1395 if (victim == root_mem) {
1396 loop++;
1397 if (loop >= 1)
1398 drain_all_stock_async();
1399 if (loop >= 2) {
1401 * If we have not been able to reclaim
1402 * anything, it might because there are
1403 * no reclaimable pages under this hierarchy
1405 if (!check_soft || !total) {
1406 css_put(&victim->css);
1407 break;
1410 * We want to do more targetted reclaim.
1411 * excess >> 2 is not to excessive so as to
1412 * reclaim too much, nor too less that we keep
1413 * coming back to reclaim from this cgroup
1415 if (total >= (excess >> 2) ||
1416 (loop > MEM_CGROUP_MAX_RECLAIM_LOOPS)) {
1417 css_put(&victim->css);
1418 break;
1422 if (!mem_cgroup_local_usage(victim)) {
1423 /* this cgroup's local usage == 0 */
1424 css_put(&victim->css);
1425 continue;
1427 /* we use swappiness of local cgroup */
1428 if (check_soft)
1429 ret = mem_cgroup_shrink_node_zone(victim, gfp_mask,
1430 noswap, get_swappiness(victim), zone);
1431 else
1432 ret = try_to_free_mem_cgroup_pages(victim, gfp_mask,
1433 noswap, get_swappiness(victim));
1434 css_put(&victim->css);
1436 * At shrinking usage, we can't check we should stop here or
1437 * reclaim more. It's depends on callers. last_scanned_child
1438 * will work enough for keeping fairness under tree.
1440 if (shrink)
1441 return ret;
1442 total += ret;
1443 if (check_soft) {
1444 if (res_counter_check_under_soft_limit(&root_mem->res))
1445 return total;
1446 } else if (mem_cgroup_check_under_limit(root_mem))
1447 return 1 + total;
1449 return total;
1453 * Check OOM-Killer is already running under our hierarchy.
1454 * If someone is running, return false.
1456 static bool mem_cgroup_oom_lock(struct mem_cgroup *mem)
1458 int x, lock_count = 0;
1459 struct mem_cgroup *iter;
1461 for_each_mem_cgroup_tree(iter, mem) {
1462 x = atomic_inc_return(&iter->oom_lock);
1463 lock_count = max(x, lock_count);
1466 if (lock_count == 1)
1467 return true;
1468 return false;
1471 static int mem_cgroup_oom_unlock(struct mem_cgroup *mem)
1473 struct mem_cgroup *iter;
1476 * When a new child is created while the hierarchy is under oom,
1477 * mem_cgroup_oom_lock() may not be called. We have to use
1478 * atomic_add_unless() here.
1480 for_each_mem_cgroup_tree(iter, mem)
1481 atomic_add_unless(&iter->oom_lock, -1, 0);
1482 return 0;
1486 static DEFINE_MUTEX(memcg_oom_mutex);
1487 static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq);
1489 struct oom_wait_info {
1490 struct mem_cgroup *mem;
1491 wait_queue_t wait;
1494 static int memcg_oom_wake_function(wait_queue_t *wait,
1495 unsigned mode, int sync, void *arg)
1497 struct mem_cgroup *wake_mem = (struct mem_cgroup *)arg;
1498 struct oom_wait_info *oom_wait_info;
1500 oom_wait_info = container_of(wait, struct oom_wait_info, wait);
1502 if (oom_wait_info->mem == wake_mem)
1503 goto wakeup;
1504 /* if no hierarchy, no match */
1505 if (!oom_wait_info->mem->use_hierarchy || !wake_mem->use_hierarchy)
1506 return 0;
1508 * Both of oom_wait_info->mem and wake_mem are stable under us.
1509 * Then we can use css_is_ancestor without taking care of RCU.
1511 if (!css_is_ancestor(&oom_wait_info->mem->css, &wake_mem->css) &&
1512 !css_is_ancestor(&wake_mem->css, &oom_wait_info->mem->css))
1513 return 0;
1515 wakeup:
1516 return autoremove_wake_function(wait, mode, sync, arg);
1519 static void memcg_wakeup_oom(struct mem_cgroup *mem)
1521 /* for filtering, pass "mem" as argument. */
1522 __wake_up(&memcg_oom_waitq, TASK_NORMAL, 0, mem);
1525 static void memcg_oom_recover(struct mem_cgroup *mem)
1527 if (mem && atomic_read(&mem->oom_lock))
1528 memcg_wakeup_oom(mem);
1532 * try to call OOM killer. returns false if we should exit memory-reclaim loop.
1534 bool mem_cgroup_handle_oom(struct mem_cgroup *mem, gfp_t mask)
1536 struct oom_wait_info owait;
1537 bool locked, need_to_kill;
1539 owait.mem = mem;
1540 owait.wait.flags = 0;
1541 owait.wait.func = memcg_oom_wake_function;
1542 owait.wait.private = current;
1543 INIT_LIST_HEAD(&owait.wait.task_list);
1544 need_to_kill = true;
1545 /* At first, try to OOM lock hierarchy under mem.*/
1546 mutex_lock(&memcg_oom_mutex);
1547 locked = mem_cgroup_oom_lock(mem);
1549 * Even if signal_pending(), we can't quit charge() loop without
1550 * accounting. So, UNINTERRUPTIBLE is appropriate. But SIGKILL
1551 * under OOM is always welcomed, use TASK_KILLABLE here.
1553 prepare_to_wait(&memcg_oom_waitq, &owait.wait, TASK_KILLABLE);
1554 if (!locked || mem->oom_kill_disable)
1555 need_to_kill = false;
1556 if (locked)
1557 mem_cgroup_oom_notify(mem);
1558 mutex_unlock(&memcg_oom_mutex);
1560 if (need_to_kill) {
1561 finish_wait(&memcg_oom_waitq, &owait.wait);
1562 mem_cgroup_out_of_memory(mem, mask);
1563 } else {
1564 schedule();
1565 finish_wait(&memcg_oom_waitq, &owait.wait);
1567 mutex_lock(&memcg_oom_mutex);
1568 mem_cgroup_oom_unlock(mem);
1569 memcg_wakeup_oom(mem);
1570 mutex_unlock(&memcg_oom_mutex);
1572 if (test_thread_flag(TIF_MEMDIE) || fatal_signal_pending(current))
1573 return false;
1574 /* Give chance to dying process */
1575 schedule_timeout(1);
1576 return true;
1580 * Currently used to update mapped file statistics, but the routine can be
1581 * generalized to update other statistics as well.
1583 * Notes: Race condition
1585 * We usually use page_cgroup_lock() for accessing page_cgroup member but
1586 * it tends to be costly. But considering some conditions, we doesn't need
1587 * to do so _always_.
1589 * Considering "charge", lock_page_cgroup() is not required because all
1590 * file-stat operations happen after a page is attached to radix-tree. There
1591 * are no race with "charge".
1593 * Considering "uncharge", we know that memcg doesn't clear pc->mem_cgroup
1594 * at "uncharge" intentionally. So, we always see valid pc->mem_cgroup even
1595 * if there are race with "uncharge". Statistics itself is properly handled
1596 * by flags.
1598 * Considering "move", this is an only case we see a race. To make the race
1599 * small, we check MEM_CGROUP_ON_MOVE percpu value and detect there are
1600 * possibility of race condition. If there is, we take a lock.
1603 static void mem_cgroup_update_file_stat(struct page *page, int idx, int val)
1605 struct mem_cgroup *mem;
1606 struct page_cgroup *pc = lookup_page_cgroup(page);
1607 bool need_unlock = false;
1609 if (unlikely(!pc))
1610 return;
1612 rcu_read_lock();
1613 mem = pc->mem_cgroup;
1614 if (unlikely(!mem || !PageCgroupUsed(pc)))
1615 goto out;
1616 /* pc->mem_cgroup is unstable ? */
1617 if (unlikely(mem_cgroup_stealed(mem))) {
1618 /* take a lock against to access pc->mem_cgroup */
1619 lock_page_cgroup(pc);
1620 need_unlock = true;
1621 mem = pc->mem_cgroup;
1622 if (!mem || !PageCgroupUsed(pc))
1623 goto out;
1626 this_cpu_add(mem->stat->count[idx], val);
1628 switch (idx) {
1629 case MEM_CGROUP_STAT_FILE_MAPPED:
1630 if (val > 0)
1631 SetPageCgroupFileMapped(pc);
1632 else if (!page_mapped(page))
1633 ClearPageCgroupFileMapped(pc);
1634 break;
1635 default:
1636 BUG();
1639 out:
1640 if (unlikely(need_unlock))
1641 unlock_page_cgroup(pc);
1642 rcu_read_unlock();
1643 return;
1646 void mem_cgroup_update_file_mapped(struct page *page, int val)
1648 mem_cgroup_update_file_stat(page, MEM_CGROUP_STAT_FILE_MAPPED, val);
1652 * size of first charge trial. "32" comes from vmscan.c's magic value.
1653 * TODO: maybe necessary to use big numbers in big irons.
1655 #define CHARGE_SIZE (32 * PAGE_SIZE)
1656 struct memcg_stock_pcp {
1657 struct mem_cgroup *cached; /* this never be root cgroup */
1658 int charge;
1659 struct work_struct work;
1661 static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock);
1662 static atomic_t memcg_drain_count;
1665 * Try to consume stocked charge on this cpu. If success, PAGE_SIZE is consumed
1666 * from local stock and true is returned. If the stock is 0 or charges from a
1667 * cgroup which is not current target, returns false. This stock will be
1668 * refilled.
1670 static bool consume_stock(struct mem_cgroup *mem)
1672 struct memcg_stock_pcp *stock;
1673 bool ret = true;
1675 stock = &get_cpu_var(memcg_stock);
1676 if (mem == stock->cached && stock->charge)
1677 stock->charge -= PAGE_SIZE;
1678 else /* need to call res_counter_charge */
1679 ret = false;
1680 put_cpu_var(memcg_stock);
1681 return ret;
1685 * Returns stocks cached in percpu to res_counter and reset cached information.
1687 static void drain_stock(struct memcg_stock_pcp *stock)
1689 struct mem_cgroup *old = stock->cached;
1691 if (stock->charge) {
1692 res_counter_uncharge(&old->res, stock->charge);
1693 if (do_swap_account)
1694 res_counter_uncharge(&old->memsw, stock->charge);
1696 stock->cached = NULL;
1697 stock->charge = 0;
1701 * This must be called under preempt disabled or must be called by
1702 * a thread which is pinned to local cpu.
1704 static void drain_local_stock(struct work_struct *dummy)
1706 struct memcg_stock_pcp *stock = &__get_cpu_var(memcg_stock);
1707 drain_stock(stock);
1711 * Cache charges(val) which is from res_counter, to local per_cpu area.
1712 * This will be consumed by consume_stock() function, later.
1714 static void refill_stock(struct mem_cgroup *mem, int val)
1716 struct memcg_stock_pcp *stock = &get_cpu_var(memcg_stock);
1718 if (stock->cached != mem) { /* reset if necessary */
1719 drain_stock(stock);
1720 stock->cached = mem;
1722 stock->charge += val;
1723 put_cpu_var(memcg_stock);
1727 * Tries to drain stocked charges in other cpus. This function is asynchronous
1728 * and just put a work per cpu for draining localy on each cpu. Caller can
1729 * expects some charges will be back to res_counter later but cannot wait for
1730 * it.
1732 static void drain_all_stock_async(void)
1734 int cpu;
1735 /* This function is for scheduling "drain" in asynchronous way.
1736 * The result of "drain" is not directly handled by callers. Then,
1737 * if someone is calling drain, we don't have to call drain more.
1738 * Anyway, WORK_STRUCT_PENDING check in queue_work_on() will catch if
1739 * there is a race. We just do loose check here.
1741 if (atomic_read(&memcg_drain_count))
1742 return;
1743 /* Notify other cpus that system-wide "drain" is running */
1744 atomic_inc(&memcg_drain_count);
1745 get_online_cpus();
1746 for_each_online_cpu(cpu) {
1747 struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
1748 schedule_work_on(cpu, &stock->work);
1750 put_online_cpus();
1751 atomic_dec(&memcg_drain_count);
1752 /* We don't wait for flush_work */
1755 /* This is a synchronous drain interface. */
1756 static void drain_all_stock_sync(void)
1758 /* called when force_empty is called */
1759 atomic_inc(&memcg_drain_count);
1760 schedule_on_each_cpu(drain_local_stock);
1761 atomic_dec(&memcg_drain_count);
1765 * This function drains percpu counter value from DEAD cpu and
1766 * move it to local cpu. Note that this function can be preempted.
1768 static void mem_cgroup_drain_pcp_counter(struct mem_cgroup *mem, int cpu)
1770 int i;
1772 spin_lock(&mem->pcp_counter_lock);
1773 for (i = 0; i < MEM_CGROUP_STAT_DATA; i++) {
1774 s64 x = per_cpu(mem->stat->count[i], cpu);
1776 per_cpu(mem->stat->count[i], cpu) = 0;
1777 mem->nocpu_base.count[i] += x;
1779 /* need to clear ON_MOVE value, works as a kind of lock. */
1780 per_cpu(mem->stat->count[MEM_CGROUP_ON_MOVE], cpu) = 0;
1781 spin_unlock(&mem->pcp_counter_lock);
1784 static void synchronize_mem_cgroup_on_move(struct mem_cgroup *mem, int cpu)
1786 int idx = MEM_CGROUP_ON_MOVE;
1788 spin_lock(&mem->pcp_counter_lock);
1789 per_cpu(mem->stat->count[idx], cpu) = mem->nocpu_base.count[idx];
1790 spin_unlock(&mem->pcp_counter_lock);
1793 static int __cpuinit memcg_cpu_hotplug_callback(struct notifier_block *nb,
1794 unsigned long action,
1795 void *hcpu)
1797 int cpu = (unsigned long)hcpu;
1798 struct memcg_stock_pcp *stock;
1799 struct mem_cgroup *iter;
1801 if ((action == CPU_ONLINE)) {
1802 for_each_mem_cgroup_all(iter)
1803 synchronize_mem_cgroup_on_move(iter, cpu);
1804 return NOTIFY_OK;
1807 if ((action != CPU_DEAD) || action != CPU_DEAD_FROZEN)
1808 return NOTIFY_OK;
1810 for_each_mem_cgroup_all(iter)
1811 mem_cgroup_drain_pcp_counter(iter, cpu);
1813 stock = &per_cpu(memcg_stock, cpu);
1814 drain_stock(stock);
1815 return NOTIFY_OK;
1819 /* See __mem_cgroup_try_charge() for details */
1820 enum {
1821 CHARGE_OK, /* success */
1822 CHARGE_RETRY, /* need to retry but retry is not bad */
1823 CHARGE_NOMEM, /* we can't do more. return -ENOMEM */
1824 CHARGE_WOULDBLOCK, /* GFP_WAIT wasn't set and no enough res. */
1825 CHARGE_OOM_DIE, /* the current is killed because of OOM */
1828 static int __mem_cgroup_do_charge(struct mem_cgroup *mem, gfp_t gfp_mask,
1829 int csize, bool oom_check)
1831 struct mem_cgroup *mem_over_limit;
1832 struct res_counter *fail_res;
1833 unsigned long flags = 0;
1834 int ret;
1836 ret = res_counter_charge(&mem->res, csize, &fail_res);
1838 if (likely(!ret)) {
1839 if (!do_swap_account)
1840 return CHARGE_OK;
1841 ret = res_counter_charge(&mem->memsw, csize, &fail_res);
1842 if (likely(!ret))
1843 return CHARGE_OK;
1845 mem_over_limit = mem_cgroup_from_res_counter(fail_res, memsw);
1846 flags |= MEM_CGROUP_RECLAIM_NOSWAP;
1847 } else
1848 mem_over_limit = mem_cgroup_from_res_counter(fail_res, res);
1850 if (csize > PAGE_SIZE) /* change csize and retry */
1851 return CHARGE_RETRY;
1853 if (!(gfp_mask & __GFP_WAIT))
1854 return CHARGE_WOULDBLOCK;
1856 ret = mem_cgroup_hierarchical_reclaim(mem_over_limit, NULL,
1857 gfp_mask, flags);
1859 * try_to_free_mem_cgroup_pages() might not give us a full
1860 * picture of reclaim. Some pages are reclaimed and might be
1861 * moved to swap cache or just unmapped from the cgroup.
1862 * Check the limit again to see if the reclaim reduced the
1863 * current usage of the cgroup before giving up
1865 if (ret || mem_cgroup_check_under_limit(mem_over_limit))
1866 return CHARGE_RETRY;
1869 * At task move, charge accounts can be doubly counted. So, it's
1870 * better to wait until the end of task_move if something is going on.
1872 if (mem_cgroup_wait_acct_move(mem_over_limit))
1873 return CHARGE_RETRY;
1875 /* If we don't need to call oom-killer at el, return immediately */
1876 if (!oom_check)
1877 return CHARGE_NOMEM;
1878 /* check OOM */
1879 if (!mem_cgroup_handle_oom(mem_over_limit, gfp_mask))
1880 return CHARGE_OOM_DIE;
1882 return CHARGE_RETRY;
1886 * Unlike exported interface, "oom" parameter is added. if oom==true,
1887 * oom-killer can be invoked.
1889 static int __mem_cgroup_try_charge(struct mm_struct *mm,
1890 gfp_t gfp_mask, struct mem_cgroup **memcg, bool oom)
1892 int nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES;
1893 struct mem_cgroup *mem = NULL;
1894 int ret;
1895 int csize = CHARGE_SIZE;
1898 * Unlike gloval-vm's OOM-kill, we're not in memory shortage
1899 * in system level. So, allow to go ahead dying process in addition to
1900 * MEMDIE process.
1902 if (unlikely(test_thread_flag(TIF_MEMDIE)
1903 || fatal_signal_pending(current)))
1904 goto bypass;
1907 * We always charge the cgroup the mm_struct belongs to.
1908 * The mm_struct's mem_cgroup changes on task migration if the
1909 * thread group leader migrates. It's possible that mm is not
1910 * set, if so charge the init_mm (happens for pagecache usage).
1912 if (!*memcg && !mm)
1913 goto bypass;
1914 again:
1915 if (*memcg) { /* css should be a valid one */
1916 mem = *memcg;
1917 VM_BUG_ON(css_is_removed(&mem->css));
1918 if (mem_cgroup_is_root(mem))
1919 goto done;
1920 if (consume_stock(mem))
1921 goto done;
1922 css_get(&mem->css);
1923 } else {
1924 struct task_struct *p;
1926 rcu_read_lock();
1927 p = rcu_dereference(mm->owner);
1928 VM_BUG_ON(!p);
1930 * because we don't have task_lock(), "p" can exit while
1931 * we're here. In that case, "mem" can point to root
1932 * cgroup but never be NULL. (and task_struct itself is freed
1933 * by RCU, cgroup itself is RCU safe.) Then, we have small
1934 * risk here to get wrong cgroup. But such kind of mis-account
1935 * by race always happens because we don't have cgroup_mutex().
1936 * It's overkill and we allow that small race, here.
1938 mem = mem_cgroup_from_task(p);
1939 VM_BUG_ON(!mem);
1940 if (mem_cgroup_is_root(mem)) {
1941 rcu_read_unlock();
1942 goto done;
1944 if (consume_stock(mem)) {
1946 * It seems dagerous to access memcg without css_get().
1947 * But considering how consume_stok works, it's not
1948 * necessary. If consume_stock success, some charges
1949 * from this memcg are cached on this cpu. So, we
1950 * don't need to call css_get()/css_tryget() before
1951 * calling consume_stock().
1953 rcu_read_unlock();
1954 goto done;
1956 /* after here, we may be blocked. we need to get refcnt */
1957 if (!css_tryget(&mem->css)) {
1958 rcu_read_unlock();
1959 goto again;
1961 rcu_read_unlock();
1964 do {
1965 bool oom_check;
1967 /* If killed, bypass charge */
1968 if (fatal_signal_pending(current)) {
1969 css_put(&mem->css);
1970 goto bypass;
1973 oom_check = false;
1974 if (oom && !nr_oom_retries) {
1975 oom_check = true;
1976 nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES;
1979 ret = __mem_cgroup_do_charge(mem, gfp_mask, csize, oom_check);
1981 switch (ret) {
1982 case CHARGE_OK:
1983 break;
1984 case CHARGE_RETRY: /* not in OOM situation but retry */
1985 csize = PAGE_SIZE;
1986 css_put(&mem->css);
1987 mem = NULL;
1988 goto again;
1989 case CHARGE_WOULDBLOCK: /* !__GFP_WAIT */
1990 css_put(&mem->css);
1991 goto nomem;
1992 case CHARGE_NOMEM: /* OOM routine works */
1993 if (!oom) {
1994 css_put(&mem->css);
1995 goto nomem;
1997 /* If oom, we never return -ENOMEM */
1998 nr_oom_retries--;
1999 break;
2000 case CHARGE_OOM_DIE: /* Killed by OOM Killer */
2001 css_put(&mem->css);
2002 goto bypass;
2004 } while (ret != CHARGE_OK);
2006 if (csize > PAGE_SIZE)
2007 refill_stock(mem, csize - PAGE_SIZE);
2008 css_put(&mem->css);
2009 done:
2010 *memcg = mem;
2011 return 0;
2012 nomem:
2013 *memcg = NULL;
2014 return -ENOMEM;
2015 bypass:
2016 *memcg = NULL;
2017 return 0;
2021 * Somemtimes we have to undo a charge we got by try_charge().
2022 * This function is for that and do uncharge, put css's refcnt.
2023 * gotten by try_charge().
2025 static void __mem_cgroup_cancel_charge(struct mem_cgroup *mem,
2026 unsigned long count)
2028 if (!mem_cgroup_is_root(mem)) {
2029 res_counter_uncharge(&mem->res, PAGE_SIZE * count);
2030 if (do_swap_account)
2031 res_counter_uncharge(&mem->memsw, PAGE_SIZE * count);
2035 static void mem_cgroup_cancel_charge(struct mem_cgroup *mem)
2037 __mem_cgroup_cancel_charge(mem, 1);
2041 * A helper function to get mem_cgroup from ID. must be called under
2042 * rcu_read_lock(). The caller must check css_is_removed() or some if
2043 * it's concern. (dropping refcnt from swap can be called against removed
2044 * memcg.)
2046 static struct mem_cgroup *mem_cgroup_lookup(unsigned short id)
2048 struct cgroup_subsys_state *css;
2050 /* ID 0 is unused ID */
2051 if (!id)
2052 return NULL;
2053 css = css_lookup(&mem_cgroup_subsys, id);
2054 if (!css)
2055 return NULL;
2056 return container_of(css, struct mem_cgroup, css);
2059 struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page)
2061 struct mem_cgroup *mem = NULL;
2062 struct page_cgroup *pc;
2063 unsigned short id;
2064 swp_entry_t ent;
2066 VM_BUG_ON(!PageLocked(page));
2068 pc = lookup_page_cgroup(page);
2069 lock_page_cgroup(pc);
2070 if (PageCgroupUsed(pc)) {
2071 mem = pc->mem_cgroup;
2072 if (mem && !css_tryget(&mem->css))
2073 mem = NULL;
2074 } else if (PageSwapCache(page)) {
2075 ent.val = page_private(page);
2076 id = lookup_swap_cgroup(ent);
2077 rcu_read_lock();
2078 mem = mem_cgroup_lookup(id);
2079 if (mem && !css_tryget(&mem->css))
2080 mem = NULL;
2081 rcu_read_unlock();
2083 unlock_page_cgroup(pc);
2084 return mem;
2088 * commit a charge got by __mem_cgroup_try_charge() and makes page_cgroup to be
2089 * USED state. If already USED, uncharge and return.
2092 static void __mem_cgroup_commit_charge(struct mem_cgroup *mem,
2093 struct page_cgroup *pc,
2094 enum charge_type ctype)
2096 /* try_charge() can return NULL to *memcg, taking care of it. */
2097 if (!mem)
2098 return;
2100 lock_page_cgroup(pc);
2101 if (unlikely(PageCgroupUsed(pc))) {
2102 unlock_page_cgroup(pc);
2103 mem_cgroup_cancel_charge(mem);
2104 return;
2107 pc->mem_cgroup = mem;
2109 * We access a page_cgroup asynchronously without lock_page_cgroup().
2110 * Especially when a page_cgroup is taken from a page, pc->mem_cgroup
2111 * is accessed after testing USED bit. To make pc->mem_cgroup visible
2112 * before USED bit, we need memory barrier here.
2113 * See mem_cgroup_add_lru_list(), etc.
2115 smp_wmb();
2116 switch (ctype) {
2117 case MEM_CGROUP_CHARGE_TYPE_CACHE:
2118 case MEM_CGROUP_CHARGE_TYPE_SHMEM:
2119 SetPageCgroupCache(pc);
2120 SetPageCgroupUsed(pc);
2121 break;
2122 case MEM_CGROUP_CHARGE_TYPE_MAPPED:
2123 ClearPageCgroupCache(pc);
2124 SetPageCgroupUsed(pc);
2125 break;
2126 default:
2127 break;
2130 mem_cgroup_charge_statistics(mem, pc, true);
2132 unlock_page_cgroup(pc);
2134 * "charge_statistics" updated event counter. Then, check it.
2135 * Insert ancestor (and ancestor's ancestors), to softlimit RB-tree.
2136 * if they exceeds softlimit.
2138 memcg_check_events(mem, pc->page);
2142 * __mem_cgroup_move_account - move account of the page
2143 * @pc: page_cgroup of the page.
2144 * @from: mem_cgroup which the page is moved from.
2145 * @to: mem_cgroup which the page is moved to. @from != @to.
2146 * @uncharge: whether we should call uncharge and css_put against @from.
2148 * The caller must confirm following.
2149 * - page is not on LRU (isolate_page() is useful.)
2150 * - the pc is locked, used, and ->mem_cgroup points to @from.
2152 * This function doesn't do "charge" nor css_get to new cgroup. It should be
2153 * done by a caller(__mem_cgroup_try_charge would be usefull). If @uncharge is
2154 * true, this function does "uncharge" from old cgroup, but it doesn't if
2155 * @uncharge is false, so a caller should do "uncharge".
2158 static void __mem_cgroup_move_account(struct page_cgroup *pc,
2159 struct mem_cgroup *from, struct mem_cgroup *to, bool uncharge)
2161 VM_BUG_ON(from == to);
2162 VM_BUG_ON(PageLRU(pc->page));
2163 VM_BUG_ON(!page_is_cgroup_locked(pc));
2164 VM_BUG_ON(!PageCgroupUsed(pc));
2165 VM_BUG_ON(pc->mem_cgroup != from);
2167 if (PageCgroupFileMapped(pc)) {
2168 /* Update mapped_file data for mem_cgroup */
2169 preempt_disable();
2170 __this_cpu_dec(from->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]);
2171 __this_cpu_inc(to->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]);
2172 preempt_enable();
2174 mem_cgroup_charge_statistics(from, pc, false);
2175 if (uncharge)
2176 /* This is not "cancel", but cancel_charge does all we need. */
2177 mem_cgroup_cancel_charge(from);
2179 /* caller should have done css_get */
2180 pc->mem_cgroup = to;
2181 mem_cgroup_charge_statistics(to, pc, true);
2183 * We charges against "to" which may not have any tasks. Then, "to"
2184 * can be under rmdir(). But in current implementation, caller of
2185 * this function is just force_empty() and move charge, so it's
2186 * garanteed that "to" is never removed. So, we don't check rmdir
2187 * status here.
2192 * check whether the @pc is valid for moving account and call
2193 * __mem_cgroup_move_account()
2195 static int mem_cgroup_move_account(struct page_cgroup *pc,
2196 struct mem_cgroup *from, struct mem_cgroup *to, bool uncharge)
2198 int ret = -EINVAL;
2199 lock_page_cgroup(pc);
2200 if (PageCgroupUsed(pc) && pc->mem_cgroup == from) {
2201 __mem_cgroup_move_account(pc, from, to, uncharge);
2202 ret = 0;
2204 unlock_page_cgroup(pc);
2206 * check events
2208 memcg_check_events(to, pc->page);
2209 memcg_check_events(from, pc->page);
2210 return ret;
2214 * move charges to its parent.
2217 static int mem_cgroup_move_parent(struct page_cgroup *pc,
2218 struct mem_cgroup *child,
2219 gfp_t gfp_mask)
2221 struct page *page = pc->page;
2222 struct cgroup *cg = child->css.cgroup;
2223 struct cgroup *pcg = cg->parent;
2224 struct mem_cgroup *parent;
2225 int ret;
2227 /* Is ROOT ? */
2228 if (!pcg)
2229 return -EINVAL;
2231 ret = -EBUSY;
2232 if (!get_page_unless_zero(page))
2233 goto out;
2234 if (isolate_lru_page(page))
2235 goto put;
2237 parent = mem_cgroup_from_cont(pcg);
2238 ret = __mem_cgroup_try_charge(NULL, gfp_mask, &parent, false);
2239 if (ret || !parent)
2240 goto put_back;
2242 ret = mem_cgroup_move_account(pc, child, parent, true);
2243 if (ret)
2244 mem_cgroup_cancel_charge(parent);
2245 put_back:
2246 putback_lru_page(page);
2247 put:
2248 put_page(page);
2249 out:
2250 return ret;
2254 * Charge the memory controller for page usage.
2255 * Return
2256 * 0 if the charge was successful
2257 * < 0 if the cgroup is over its limit
2259 static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm,
2260 gfp_t gfp_mask, enum charge_type ctype)
2262 struct mem_cgroup *mem = NULL;
2263 struct page_cgroup *pc;
2264 int ret;
2266 pc = lookup_page_cgroup(page);
2267 /* can happen at boot */
2268 if (unlikely(!pc))
2269 return 0;
2270 prefetchw(pc);
2272 ret = __mem_cgroup_try_charge(mm, gfp_mask, &mem, true);
2273 if (ret || !mem)
2274 return ret;
2276 __mem_cgroup_commit_charge(mem, pc, ctype);
2277 return 0;
2280 int mem_cgroup_newpage_charge(struct page *page,
2281 struct mm_struct *mm, gfp_t gfp_mask)
2283 if (mem_cgroup_disabled())
2284 return 0;
2285 if (PageCompound(page))
2286 return 0;
2288 * If already mapped, we don't have to account.
2289 * If page cache, page->mapping has address_space.
2290 * But page->mapping may have out-of-use anon_vma pointer,
2291 * detecit it by PageAnon() check. newly-mapped-anon's page->mapping
2292 * is NULL.
2294 if (page_mapped(page) || (page->mapping && !PageAnon(page)))
2295 return 0;
2296 if (unlikely(!mm))
2297 mm = &init_mm;
2298 return mem_cgroup_charge_common(page, mm, gfp_mask,
2299 MEM_CGROUP_CHARGE_TYPE_MAPPED);
2302 static void
2303 __mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr,
2304 enum charge_type ctype);
2306 int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
2307 gfp_t gfp_mask)
2309 int ret;
2311 if (mem_cgroup_disabled())
2312 return 0;
2313 if (PageCompound(page))
2314 return 0;
2316 * Corner case handling. This is called from add_to_page_cache()
2317 * in usual. But some FS (shmem) precharges this page before calling it
2318 * and call add_to_page_cache() with GFP_NOWAIT.
2320 * For GFP_NOWAIT case, the page may be pre-charged before calling
2321 * add_to_page_cache(). (See shmem.c) check it here and avoid to call
2322 * charge twice. (It works but has to pay a bit larger cost.)
2323 * And when the page is SwapCache, it should take swap information
2324 * into account. This is under lock_page() now.
2326 if (!(gfp_mask & __GFP_WAIT)) {
2327 struct page_cgroup *pc;
2329 pc = lookup_page_cgroup(page);
2330 if (!pc)
2331 return 0;
2332 lock_page_cgroup(pc);
2333 if (PageCgroupUsed(pc)) {
2334 unlock_page_cgroup(pc);
2335 return 0;
2337 unlock_page_cgroup(pc);
2340 if (unlikely(!mm))
2341 mm = &init_mm;
2343 if (page_is_file_cache(page))
2344 return mem_cgroup_charge_common(page, mm, gfp_mask,
2345 MEM_CGROUP_CHARGE_TYPE_CACHE);
2347 /* shmem */
2348 if (PageSwapCache(page)) {
2349 struct mem_cgroup *mem = NULL;
2351 ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &mem);
2352 if (!ret)
2353 __mem_cgroup_commit_charge_swapin(page, mem,
2354 MEM_CGROUP_CHARGE_TYPE_SHMEM);
2355 } else
2356 ret = mem_cgroup_charge_common(page, mm, gfp_mask,
2357 MEM_CGROUP_CHARGE_TYPE_SHMEM);
2359 return ret;
2363 * While swap-in, try_charge -> commit or cancel, the page is locked.
2364 * And when try_charge() successfully returns, one refcnt to memcg without
2365 * struct page_cgroup is acquired. This refcnt will be consumed by
2366 * "commit()" or removed by "cancel()"
2368 int mem_cgroup_try_charge_swapin(struct mm_struct *mm,
2369 struct page *page,
2370 gfp_t mask, struct mem_cgroup **ptr)
2372 struct mem_cgroup *mem;
2373 int ret;
2375 if (mem_cgroup_disabled())
2376 return 0;
2378 if (!do_swap_account)
2379 goto charge_cur_mm;
2381 * A racing thread's fault, or swapoff, may have already updated
2382 * the pte, and even removed page from swap cache: in those cases
2383 * do_swap_page()'s pte_same() test will fail; but there's also a
2384 * KSM case which does need to charge the page.
2386 if (!PageSwapCache(page))
2387 goto charge_cur_mm;
2388 mem = try_get_mem_cgroup_from_page(page);
2389 if (!mem)
2390 goto charge_cur_mm;
2391 *ptr = mem;
2392 ret = __mem_cgroup_try_charge(NULL, mask, ptr, true);
2393 css_put(&mem->css);
2394 return ret;
2395 charge_cur_mm:
2396 if (unlikely(!mm))
2397 mm = &init_mm;
2398 return __mem_cgroup_try_charge(mm, mask, ptr, true);
2401 static void
2402 __mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr,
2403 enum charge_type ctype)
2405 struct page_cgroup *pc;
2407 if (mem_cgroup_disabled())
2408 return;
2409 if (!ptr)
2410 return;
2411 cgroup_exclude_rmdir(&ptr->css);
2412 pc = lookup_page_cgroup(page);
2413 mem_cgroup_lru_del_before_commit_swapcache(page);
2414 __mem_cgroup_commit_charge(ptr, pc, ctype);
2415 mem_cgroup_lru_add_after_commit_swapcache(page);
2417 * Now swap is on-memory. This means this page may be
2418 * counted both as mem and swap....double count.
2419 * Fix it by uncharging from memsw. Basically, this SwapCache is stable
2420 * under lock_page(). But in do_swap_page()::memory.c, reuse_swap_page()
2421 * may call delete_from_swap_cache() before reach here.
2423 if (do_swap_account && PageSwapCache(page)) {
2424 swp_entry_t ent = {.val = page_private(page)};
2425 unsigned short id;
2426 struct mem_cgroup *memcg;
2428 id = swap_cgroup_record(ent, 0);
2429 rcu_read_lock();
2430 memcg = mem_cgroup_lookup(id);
2431 if (memcg) {
2433 * This recorded memcg can be obsolete one. So, avoid
2434 * calling css_tryget
2436 if (!mem_cgroup_is_root(memcg))
2437 res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
2438 mem_cgroup_swap_statistics(memcg, false);
2439 mem_cgroup_put(memcg);
2441 rcu_read_unlock();
2444 * At swapin, we may charge account against cgroup which has no tasks.
2445 * So, rmdir()->pre_destroy() can be called while we do this charge.
2446 * In that case, we need to call pre_destroy() again. check it here.
2448 cgroup_release_and_wakeup_rmdir(&ptr->css);
2451 void mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr)
2453 __mem_cgroup_commit_charge_swapin(page, ptr,
2454 MEM_CGROUP_CHARGE_TYPE_MAPPED);
2457 void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *mem)
2459 if (mem_cgroup_disabled())
2460 return;
2461 if (!mem)
2462 return;
2463 mem_cgroup_cancel_charge(mem);
2466 static void
2467 __do_uncharge(struct mem_cgroup *mem, const enum charge_type ctype)
2469 struct memcg_batch_info *batch = NULL;
2470 bool uncharge_memsw = true;
2471 /* If swapout, usage of swap doesn't decrease */
2472 if (!do_swap_account || ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT)
2473 uncharge_memsw = false;
2475 batch = &current->memcg_batch;
2477 * In usual, we do css_get() when we remember memcg pointer.
2478 * But in this case, we keep res->usage until end of a series of
2479 * uncharges. Then, it's ok to ignore memcg's refcnt.
2481 if (!batch->memcg)
2482 batch->memcg = mem;
2484 * do_batch > 0 when unmapping pages or inode invalidate/truncate.
2485 * In those cases, all pages freed continously can be expected to be in
2486 * the same cgroup and we have chance to coalesce uncharges.
2487 * But we do uncharge one by one if this is killed by OOM(TIF_MEMDIE)
2488 * because we want to do uncharge as soon as possible.
2491 if (!batch->do_batch || test_thread_flag(TIF_MEMDIE))
2492 goto direct_uncharge;
2495 * In typical case, batch->memcg == mem. This means we can
2496 * merge a series of uncharges to an uncharge of res_counter.
2497 * If not, we uncharge res_counter ony by one.
2499 if (batch->memcg != mem)
2500 goto direct_uncharge;
2501 /* remember freed charge and uncharge it later */
2502 batch->bytes += PAGE_SIZE;
2503 if (uncharge_memsw)
2504 batch->memsw_bytes += PAGE_SIZE;
2505 return;
2506 direct_uncharge:
2507 res_counter_uncharge(&mem->res, PAGE_SIZE);
2508 if (uncharge_memsw)
2509 res_counter_uncharge(&mem->memsw, PAGE_SIZE);
2510 if (unlikely(batch->memcg != mem))
2511 memcg_oom_recover(mem);
2512 return;
2516 * uncharge if !page_mapped(page)
2518 static struct mem_cgroup *
2519 __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
2521 struct page_cgroup *pc;
2522 struct mem_cgroup *mem = NULL;
2524 if (mem_cgroup_disabled())
2525 return NULL;
2527 if (PageSwapCache(page))
2528 return NULL;
2531 * Check if our page_cgroup is valid
2533 pc = lookup_page_cgroup(page);
2534 if (unlikely(!pc || !PageCgroupUsed(pc)))
2535 return NULL;
2537 lock_page_cgroup(pc);
2539 mem = pc->mem_cgroup;
2541 if (!PageCgroupUsed(pc))
2542 goto unlock_out;
2544 switch (ctype) {
2545 case MEM_CGROUP_CHARGE_TYPE_MAPPED:
2546 case MEM_CGROUP_CHARGE_TYPE_DROP:
2547 /* See mem_cgroup_prepare_migration() */
2548 if (page_mapped(page) || PageCgroupMigration(pc))
2549 goto unlock_out;
2550 break;
2551 case MEM_CGROUP_CHARGE_TYPE_SWAPOUT:
2552 if (!PageAnon(page)) { /* Shared memory */
2553 if (page->mapping && !page_is_file_cache(page))
2554 goto unlock_out;
2555 } else if (page_mapped(page)) /* Anon */
2556 goto unlock_out;
2557 break;
2558 default:
2559 break;
2562 mem_cgroup_charge_statistics(mem, pc, false);
2564 ClearPageCgroupUsed(pc);
2566 * pc->mem_cgroup is not cleared here. It will be accessed when it's
2567 * freed from LRU. This is safe because uncharged page is expected not
2568 * to be reused (freed soon). Exception is SwapCache, it's handled by
2569 * special functions.
2572 unlock_page_cgroup(pc);
2574 * even after unlock, we have mem->res.usage here and this memcg
2575 * will never be freed.
2577 memcg_check_events(mem, page);
2578 if (do_swap_account && ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT) {
2579 mem_cgroup_swap_statistics(mem, true);
2580 mem_cgroup_get(mem);
2582 if (!mem_cgroup_is_root(mem))
2583 __do_uncharge(mem, ctype);
2585 return mem;
2587 unlock_out:
2588 unlock_page_cgroup(pc);
2589 return NULL;
2592 void mem_cgroup_uncharge_page(struct page *page)
2594 /* early check. */
2595 if (page_mapped(page))
2596 return;
2597 if (page->mapping && !PageAnon(page))
2598 return;
2599 __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_MAPPED);
2602 void mem_cgroup_uncharge_cache_page(struct page *page)
2604 VM_BUG_ON(page_mapped(page));
2605 VM_BUG_ON(page->mapping);
2606 __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE);
2610 * Batch_start/batch_end is called in unmap_page_range/invlidate/trucate.
2611 * In that cases, pages are freed continuously and we can expect pages
2612 * are in the same memcg. All these calls itself limits the number of
2613 * pages freed at once, then uncharge_start/end() is called properly.
2614 * This may be called prural(2) times in a context,
2617 void mem_cgroup_uncharge_start(void)
2619 current->memcg_batch.do_batch++;
2620 /* We can do nest. */
2621 if (current->memcg_batch.do_batch == 1) {
2622 current->memcg_batch.memcg = NULL;
2623 current->memcg_batch.bytes = 0;
2624 current->memcg_batch.memsw_bytes = 0;
2628 void mem_cgroup_uncharge_end(void)
2630 struct memcg_batch_info *batch = &current->memcg_batch;
2632 if (!batch->do_batch)
2633 return;
2635 batch->do_batch--;
2636 if (batch->do_batch) /* If stacked, do nothing. */
2637 return;
2639 if (!batch->memcg)
2640 return;
2642 * This "batch->memcg" is valid without any css_get/put etc...
2643 * bacause we hide charges behind us.
2645 if (batch->bytes)
2646 res_counter_uncharge(&batch->memcg->res, batch->bytes);
2647 if (batch->memsw_bytes)
2648 res_counter_uncharge(&batch->memcg->memsw, batch->memsw_bytes);
2649 memcg_oom_recover(batch->memcg);
2650 /* forget this pointer (for sanity check) */
2651 batch->memcg = NULL;
2654 #ifdef CONFIG_SWAP
2656 * called after __delete_from_swap_cache() and drop "page" account.
2657 * memcg information is recorded to swap_cgroup of "ent"
2659 void
2660 mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout)
2662 struct mem_cgroup *memcg;
2663 int ctype = MEM_CGROUP_CHARGE_TYPE_SWAPOUT;
2665 if (!swapout) /* this was a swap cache but the swap is unused ! */
2666 ctype = MEM_CGROUP_CHARGE_TYPE_DROP;
2668 memcg = __mem_cgroup_uncharge_common(page, ctype);
2671 * record memcg information, if swapout && memcg != NULL,
2672 * mem_cgroup_get() was called in uncharge().
2674 if (do_swap_account && swapout && memcg)
2675 swap_cgroup_record(ent, css_id(&memcg->css));
2677 #endif
2679 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
2681 * called from swap_entry_free(). remove record in swap_cgroup and
2682 * uncharge "memsw" account.
2684 void mem_cgroup_uncharge_swap(swp_entry_t ent)
2686 struct mem_cgroup *memcg;
2687 unsigned short id;
2689 if (!do_swap_account)
2690 return;
2692 id = swap_cgroup_record(ent, 0);
2693 rcu_read_lock();
2694 memcg = mem_cgroup_lookup(id);
2695 if (memcg) {
2697 * We uncharge this because swap is freed.
2698 * This memcg can be obsolete one. We avoid calling css_tryget
2700 if (!mem_cgroup_is_root(memcg))
2701 res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
2702 mem_cgroup_swap_statistics(memcg, false);
2703 mem_cgroup_put(memcg);
2705 rcu_read_unlock();
2709 * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record.
2710 * @entry: swap entry to be moved
2711 * @from: mem_cgroup which the entry is moved from
2712 * @to: mem_cgroup which the entry is moved to
2713 * @need_fixup: whether we should fixup res_counters and refcounts.
2715 * It succeeds only when the swap_cgroup's record for this entry is the same
2716 * as the mem_cgroup's id of @from.
2718 * Returns 0 on success, -EINVAL on failure.
2720 * The caller must have charged to @to, IOW, called res_counter_charge() about
2721 * both res and memsw, and called css_get().
2723 static int mem_cgroup_move_swap_account(swp_entry_t entry,
2724 struct mem_cgroup *from, struct mem_cgroup *to, bool need_fixup)
2726 unsigned short old_id, new_id;
2728 old_id = css_id(&from->css);
2729 new_id = css_id(&to->css);
2731 if (swap_cgroup_cmpxchg(entry, old_id, new_id) == old_id) {
2732 mem_cgroup_swap_statistics(from, false);
2733 mem_cgroup_swap_statistics(to, true);
2735 * This function is only called from task migration context now.
2736 * It postpones res_counter and refcount handling till the end
2737 * of task migration(mem_cgroup_clear_mc()) for performance
2738 * improvement. But we cannot postpone mem_cgroup_get(to)
2739 * because if the process that has been moved to @to does
2740 * swap-in, the refcount of @to might be decreased to 0.
2742 mem_cgroup_get(to);
2743 if (need_fixup) {
2744 if (!mem_cgroup_is_root(from))
2745 res_counter_uncharge(&from->memsw, PAGE_SIZE);
2746 mem_cgroup_put(from);
2748 * we charged both to->res and to->memsw, so we should
2749 * uncharge to->res.
2751 if (!mem_cgroup_is_root(to))
2752 res_counter_uncharge(&to->res, PAGE_SIZE);
2754 return 0;
2756 return -EINVAL;
2758 #else
2759 static inline int mem_cgroup_move_swap_account(swp_entry_t entry,
2760 struct mem_cgroup *from, struct mem_cgroup *to, bool need_fixup)
2762 return -EINVAL;
2764 #endif
2767 * Before starting migration, account PAGE_SIZE to mem_cgroup that the old
2768 * page belongs to.
2770 int mem_cgroup_prepare_migration(struct page *page,
2771 struct page *newpage, struct mem_cgroup **ptr)
2773 struct page_cgroup *pc;
2774 struct mem_cgroup *mem = NULL;
2775 enum charge_type ctype;
2776 int ret = 0;
2778 if (mem_cgroup_disabled())
2779 return 0;
2781 pc = lookup_page_cgroup(page);
2782 lock_page_cgroup(pc);
2783 if (PageCgroupUsed(pc)) {
2784 mem = pc->mem_cgroup;
2785 css_get(&mem->css);
2787 * At migrating an anonymous page, its mapcount goes down
2788 * to 0 and uncharge() will be called. But, even if it's fully
2789 * unmapped, migration may fail and this page has to be
2790 * charged again. We set MIGRATION flag here and delay uncharge
2791 * until end_migration() is called
2793 * Corner Case Thinking
2794 * A)
2795 * When the old page was mapped as Anon and it's unmap-and-freed
2796 * while migration was ongoing.
2797 * If unmap finds the old page, uncharge() of it will be delayed
2798 * until end_migration(). If unmap finds a new page, it's
2799 * uncharged when it make mapcount to be 1->0. If unmap code
2800 * finds swap_migration_entry, the new page will not be mapped
2801 * and end_migration() will find it(mapcount==0).
2803 * B)
2804 * When the old page was mapped but migraion fails, the kernel
2805 * remaps it. A charge for it is kept by MIGRATION flag even
2806 * if mapcount goes down to 0. We can do remap successfully
2807 * without charging it again.
2809 * C)
2810 * The "old" page is under lock_page() until the end of
2811 * migration, so, the old page itself will not be swapped-out.
2812 * If the new page is swapped out before end_migraton, our
2813 * hook to usual swap-out path will catch the event.
2815 if (PageAnon(page))
2816 SetPageCgroupMigration(pc);
2818 unlock_page_cgroup(pc);
2820 * If the page is not charged at this point,
2821 * we return here.
2823 if (!mem)
2824 return 0;
2826 *ptr = mem;
2827 ret = __mem_cgroup_try_charge(NULL, GFP_KERNEL, ptr, false);
2828 css_put(&mem->css);/* drop extra refcnt */
2829 if (ret || *ptr == NULL) {
2830 if (PageAnon(page)) {
2831 lock_page_cgroup(pc);
2832 ClearPageCgroupMigration(pc);
2833 unlock_page_cgroup(pc);
2835 * The old page may be fully unmapped while we kept it.
2837 mem_cgroup_uncharge_page(page);
2839 return -ENOMEM;
2842 * We charge new page before it's used/mapped. So, even if unlock_page()
2843 * is called before end_migration, we can catch all events on this new
2844 * page. In the case new page is migrated but not remapped, new page's
2845 * mapcount will be finally 0 and we call uncharge in end_migration().
2847 pc = lookup_page_cgroup(newpage);
2848 if (PageAnon(page))
2849 ctype = MEM_CGROUP_CHARGE_TYPE_MAPPED;
2850 else if (page_is_file_cache(page))
2851 ctype = MEM_CGROUP_CHARGE_TYPE_CACHE;
2852 else
2853 ctype = MEM_CGROUP_CHARGE_TYPE_SHMEM;
2854 __mem_cgroup_commit_charge(mem, pc, ctype);
2855 return ret;
2858 /* remove redundant charge if migration failed*/
2859 void mem_cgroup_end_migration(struct mem_cgroup *mem,
2860 struct page *oldpage, struct page *newpage)
2862 struct page *used, *unused;
2863 struct page_cgroup *pc;
2865 if (!mem)
2866 return;
2867 /* blocks rmdir() */
2868 cgroup_exclude_rmdir(&mem->css);
2869 /* at migration success, oldpage->mapping is NULL. */
2870 if (oldpage->mapping) {
2871 used = oldpage;
2872 unused = newpage;
2873 } else {
2874 used = newpage;
2875 unused = oldpage;
2878 * We disallowed uncharge of pages under migration because mapcount
2879 * of the page goes down to zero, temporarly.
2880 * Clear the flag and check the page should be charged.
2882 pc = lookup_page_cgroup(oldpage);
2883 lock_page_cgroup(pc);
2884 ClearPageCgroupMigration(pc);
2885 unlock_page_cgroup(pc);
2887 __mem_cgroup_uncharge_common(unused, MEM_CGROUP_CHARGE_TYPE_FORCE);
2890 * If a page is a file cache, radix-tree replacement is very atomic
2891 * and we can skip this check. When it was an Anon page, its mapcount
2892 * goes down to 0. But because we added MIGRATION flage, it's not
2893 * uncharged yet. There are several case but page->mapcount check
2894 * and USED bit check in mem_cgroup_uncharge_page() will do enough
2895 * check. (see prepare_charge() also)
2897 if (PageAnon(used))
2898 mem_cgroup_uncharge_page(used);
2900 * At migration, we may charge account against cgroup which has no
2901 * tasks.
2902 * So, rmdir()->pre_destroy() can be called while we do this charge.
2903 * In that case, we need to call pre_destroy() again. check it here.
2905 cgroup_release_and_wakeup_rmdir(&mem->css);
2909 * A call to try to shrink memory usage on charge failure at shmem's swapin.
2910 * Calling hierarchical_reclaim is not enough because we should update
2911 * last_oom_jiffies to prevent pagefault_out_of_memory from invoking global OOM.
2912 * Moreover considering hierarchy, we should reclaim from the mem_over_limit,
2913 * not from the memcg which this page would be charged to.
2914 * try_charge_swapin does all of these works properly.
2916 int mem_cgroup_shmem_charge_fallback(struct page *page,
2917 struct mm_struct *mm,
2918 gfp_t gfp_mask)
2920 struct mem_cgroup *mem = NULL;
2921 int ret;
2923 if (mem_cgroup_disabled())
2924 return 0;
2926 ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &mem);
2927 if (!ret)
2928 mem_cgroup_cancel_charge_swapin(mem); /* it does !mem check */
2930 return ret;
2933 static DEFINE_MUTEX(set_limit_mutex);
2935 static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
2936 unsigned long long val)
2938 int retry_count;
2939 u64 memswlimit, memlimit;
2940 int ret = 0;
2941 int children = mem_cgroup_count_children(memcg);
2942 u64 curusage, oldusage;
2943 int enlarge;
2946 * For keeping hierarchical_reclaim simple, how long we should retry
2947 * is depends on callers. We set our retry-count to be function
2948 * of # of children which we should visit in this loop.
2950 retry_count = MEM_CGROUP_RECLAIM_RETRIES * children;
2952 oldusage = res_counter_read_u64(&memcg->res, RES_USAGE);
2954 enlarge = 0;
2955 while (retry_count) {
2956 if (signal_pending(current)) {
2957 ret = -EINTR;
2958 break;
2961 * Rather than hide all in some function, I do this in
2962 * open coded manner. You see what this really does.
2963 * We have to guarantee mem->res.limit < mem->memsw.limit.
2965 mutex_lock(&set_limit_mutex);
2966 memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
2967 if (memswlimit < val) {
2968 ret = -EINVAL;
2969 mutex_unlock(&set_limit_mutex);
2970 break;
2973 memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT);
2974 if (memlimit < val)
2975 enlarge = 1;
2977 ret = res_counter_set_limit(&memcg->res, val);
2978 if (!ret) {
2979 if (memswlimit == val)
2980 memcg->memsw_is_minimum = true;
2981 else
2982 memcg->memsw_is_minimum = false;
2984 mutex_unlock(&set_limit_mutex);
2986 if (!ret)
2987 break;
2989 mem_cgroup_hierarchical_reclaim(memcg, NULL, GFP_KERNEL,
2990 MEM_CGROUP_RECLAIM_SHRINK);
2991 curusage = res_counter_read_u64(&memcg->res, RES_USAGE);
2992 /* Usage is reduced ? */
2993 if (curusage >= oldusage)
2994 retry_count--;
2995 else
2996 oldusage = curusage;
2998 if (!ret && enlarge)
2999 memcg_oom_recover(memcg);
3001 return ret;
3004 static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
3005 unsigned long long val)
3007 int retry_count;
3008 u64 memlimit, memswlimit, oldusage, curusage;
3009 int children = mem_cgroup_count_children(memcg);
3010 int ret = -EBUSY;
3011 int enlarge = 0;
3013 /* see mem_cgroup_resize_res_limit */
3014 retry_count = children * MEM_CGROUP_RECLAIM_RETRIES;
3015 oldusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
3016 while (retry_count) {
3017 if (signal_pending(current)) {
3018 ret = -EINTR;
3019 break;
3022 * Rather than hide all in some function, I do this in
3023 * open coded manner. You see what this really does.
3024 * We have to guarantee mem->res.limit < mem->memsw.limit.
3026 mutex_lock(&set_limit_mutex);
3027 memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT);
3028 if (memlimit > val) {
3029 ret = -EINVAL;
3030 mutex_unlock(&set_limit_mutex);
3031 break;
3033 memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
3034 if (memswlimit < val)
3035 enlarge = 1;
3036 ret = res_counter_set_limit(&memcg->memsw, val);
3037 if (!ret) {
3038 if (memlimit == val)
3039 memcg->memsw_is_minimum = true;
3040 else
3041 memcg->memsw_is_minimum = false;
3043 mutex_unlock(&set_limit_mutex);
3045 if (!ret)
3046 break;
3048 mem_cgroup_hierarchical_reclaim(memcg, NULL, GFP_KERNEL,
3049 MEM_CGROUP_RECLAIM_NOSWAP |
3050 MEM_CGROUP_RECLAIM_SHRINK);
3051 curusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
3052 /* Usage is reduced ? */
3053 if (curusage >= oldusage)
3054 retry_count--;
3055 else
3056 oldusage = curusage;
3058 if (!ret && enlarge)
3059 memcg_oom_recover(memcg);
3060 return ret;
3063 unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
3064 gfp_t gfp_mask)
3066 unsigned long nr_reclaimed = 0;
3067 struct mem_cgroup_per_zone *mz, *next_mz = NULL;
3068 unsigned long reclaimed;
3069 int loop = 0;
3070 struct mem_cgroup_tree_per_zone *mctz;
3071 unsigned long long excess;
3073 if (order > 0)
3074 return 0;
3076 mctz = soft_limit_tree_node_zone(zone_to_nid(zone), zone_idx(zone));
3078 * This loop can run a while, specially if mem_cgroup's continuously
3079 * keep exceeding their soft limit and putting the system under
3080 * pressure
3082 do {
3083 if (next_mz)
3084 mz = next_mz;
3085 else
3086 mz = mem_cgroup_largest_soft_limit_node(mctz);
3087 if (!mz)
3088 break;
3090 reclaimed = mem_cgroup_hierarchical_reclaim(mz->mem, zone,
3091 gfp_mask,
3092 MEM_CGROUP_RECLAIM_SOFT);
3093 nr_reclaimed += reclaimed;
3094 spin_lock(&mctz->lock);
3097 * If we failed to reclaim anything from this memory cgroup
3098 * it is time to move on to the next cgroup
3100 next_mz = NULL;
3101 if (!reclaimed) {
3102 do {
3104 * Loop until we find yet another one.
3106 * By the time we get the soft_limit lock
3107 * again, someone might have aded the
3108 * group back on the RB tree. Iterate to
3109 * make sure we get a different mem.
3110 * mem_cgroup_largest_soft_limit_node returns
3111 * NULL if no other cgroup is present on
3112 * the tree
3114 next_mz =
3115 __mem_cgroup_largest_soft_limit_node(mctz);
3116 if (next_mz == mz) {
3117 css_put(&next_mz->mem->css);
3118 next_mz = NULL;
3119 } else /* next_mz == NULL or other memcg */
3120 break;
3121 } while (1);
3123 __mem_cgroup_remove_exceeded(mz->mem, mz, mctz);
3124 excess = res_counter_soft_limit_excess(&mz->mem->res);
3126 * One school of thought says that we should not add
3127 * back the node to the tree if reclaim returns 0.
3128 * But our reclaim could return 0, simply because due
3129 * to priority we are exposing a smaller subset of
3130 * memory to reclaim from. Consider this as a longer
3131 * term TODO.
3133 /* If excess == 0, no tree ops */
3134 __mem_cgroup_insert_exceeded(mz->mem, mz, mctz, excess);
3135 spin_unlock(&mctz->lock);
3136 css_put(&mz->mem->css);
3137 loop++;
3139 * Could not reclaim anything and there are no more
3140 * mem cgroups to try or we seem to be looping without
3141 * reclaiming anything.
3143 if (!nr_reclaimed &&
3144 (next_mz == NULL ||
3145 loop > MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS))
3146 break;
3147 } while (!nr_reclaimed);
3148 if (next_mz)
3149 css_put(&next_mz->mem->css);
3150 return nr_reclaimed;
3154 * This routine traverse page_cgroup in given list and drop them all.
3155 * *And* this routine doesn't reclaim page itself, just removes page_cgroup.
3157 static int mem_cgroup_force_empty_list(struct mem_cgroup *mem,
3158 int node, int zid, enum lru_list lru)
3160 struct zone *zone;
3161 struct mem_cgroup_per_zone *mz;
3162 struct page_cgroup *pc, *busy;
3163 unsigned long flags, loop;
3164 struct list_head *list;
3165 int ret = 0;
3167 zone = &NODE_DATA(node)->node_zones[zid];
3168 mz = mem_cgroup_zoneinfo(mem, node, zid);
3169 list = &mz->lists[lru];
3171 loop = MEM_CGROUP_ZSTAT(mz, lru);
3172 /* give some margin against EBUSY etc...*/
3173 loop += 256;
3174 busy = NULL;
3175 while (loop--) {
3176 ret = 0;
3177 spin_lock_irqsave(&zone->lru_lock, flags);
3178 if (list_empty(list)) {
3179 spin_unlock_irqrestore(&zone->lru_lock, flags);
3180 break;
3182 pc = list_entry(list->prev, struct page_cgroup, lru);
3183 if (busy == pc) {
3184 list_move(&pc->lru, list);
3185 busy = NULL;
3186 spin_unlock_irqrestore(&zone->lru_lock, flags);
3187 continue;
3189 spin_unlock_irqrestore(&zone->lru_lock, flags);
3191 ret = mem_cgroup_move_parent(pc, mem, GFP_KERNEL);
3192 if (ret == -ENOMEM)
3193 break;
3195 if (ret == -EBUSY || ret == -EINVAL) {
3196 /* found lock contention or "pc" is obsolete. */
3197 busy = pc;
3198 cond_resched();
3199 } else
3200 busy = NULL;
3203 if (!ret && !list_empty(list))
3204 return -EBUSY;
3205 return ret;
3209 * make mem_cgroup's charge to be 0 if there is no task.
3210 * This enables deleting this mem_cgroup.
3212 static int mem_cgroup_force_empty(struct mem_cgroup *mem, bool free_all)
3214 int ret;
3215 int node, zid, shrink;
3216 int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
3217 struct cgroup *cgrp = mem->css.cgroup;
3219 css_get(&mem->css);
3221 shrink = 0;
3222 /* should free all ? */
3223 if (free_all)
3224 goto try_to_free;
3225 move_account:
3226 do {
3227 ret = -EBUSY;
3228 if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children))
3229 goto out;
3230 ret = -EINTR;
3231 if (signal_pending(current))
3232 goto out;
3233 /* This is for making all *used* pages to be on LRU. */
3234 lru_add_drain_all();
3235 drain_all_stock_sync();
3236 ret = 0;
3237 mem_cgroup_start_move(mem);
3238 for_each_node_state(node, N_HIGH_MEMORY) {
3239 for (zid = 0; !ret && zid < MAX_NR_ZONES; zid++) {
3240 enum lru_list l;
3241 for_each_lru(l) {
3242 ret = mem_cgroup_force_empty_list(mem,
3243 node, zid, l);
3244 if (ret)
3245 break;
3248 if (ret)
3249 break;
3251 mem_cgroup_end_move(mem);
3252 memcg_oom_recover(mem);
3253 /* it seems parent cgroup doesn't have enough mem */
3254 if (ret == -ENOMEM)
3255 goto try_to_free;
3256 cond_resched();
3257 /* "ret" should also be checked to ensure all lists are empty. */
3258 } while (mem->res.usage > 0 || ret);
3259 out:
3260 css_put(&mem->css);
3261 return ret;
3263 try_to_free:
3264 /* returns EBUSY if there is a task or if we come here twice. */
3265 if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children) || shrink) {
3266 ret = -EBUSY;
3267 goto out;
3269 /* we call try-to-free pages for make this cgroup empty */
3270 lru_add_drain_all();
3271 /* try to free all pages in this cgroup */
3272 shrink = 1;
3273 while (nr_retries && mem->res.usage > 0) {
3274 int progress;
3276 if (signal_pending(current)) {
3277 ret = -EINTR;
3278 goto out;
3280 progress = try_to_free_mem_cgroup_pages(mem, GFP_KERNEL,
3281 false, get_swappiness(mem));
3282 if (!progress) {
3283 nr_retries--;
3284 /* maybe some writeback is necessary */
3285 congestion_wait(BLK_RW_ASYNC, HZ/10);
3289 lru_add_drain();
3290 /* try move_account...there may be some *locked* pages. */
3291 goto move_account;
3294 int mem_cgroup_force_empty_write(struct cgroup *cont, unsigned int event)
3296 return mem_cgroup_force_empty(mem_cgroup_from_cont(cont), true);
3300 static u64 mem_cgroup_hierarchy_read(struct cgroup *cont, struct cftype *cft)
3302 return mem_cgroup_from_cont(cont)->use_hierarchy;
3305 static int mem_cgroup_hierarchy_write(struct cgroup *cont, struct cftype *cft,
3306 u64 val)
3308 int retval = 0;
3309 struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
3310 struct cgroup *parent = cont->parent;
3311 struct mem_cgroup *parent_mem = NULL;
3313 if (parent)
3314 parent_mem = mem_cgroup_from_cont(parent);
3316 cgroup_lock();
3318 * If parent's use_hierarchy is set, we can't make any modifications
3319 * in the child subtrees. If it is unset, then the change can
3320 * occur, provided the current cgroup has no children.
3322 * For the root cgroup, parent_mem is NULL, we allow value to be
3323 * set if there are no children.
3325 if ((!parent_mem || !parent_mem->use_hierarchy) &&
3326 (val == 1 || val == 0)) {
3327 if (list_empty(&cont->children))
3328 mem->use_hierarchy = val;
3329 else
3330 retval = -EBUSY;
3331 } else
3332 retval = -EINVAL;
3333 cgroup_unlock();
3335 return retval;
3339 static u64 mem_cgroup_get_recursive_idx_stat(struct mem_cgroup *mem,
3340 enum mem_cgroup_stat_index idx)
3342 struct mem_cgroup *iter;
3343 s64 val = 0;
3345 /* each per cpu's value can be minus.Then, use s64 */
3346 for_each_mem_cgroup_tree(iter, mem)
3347 val += mem_cgroup_read_stat(iter, idx);
3349 if (val < 0) /* race ? */
3350 val = 0;
3351 return val;
3354 static inline u64 mem_cgroup_usage(struct mem_cgroup *mem, bool swap)
3356 u64 val;
3358 if (!mem_cgroup_is_root(mem)) {
3359 if (!swap)
3360 return res_counter_read_u64(&mem->res, RES_USAGE);
3361 else
3362 return res_counter_read_u64(&mem->memsw, RES_USAGE);
3365 val = mem_cgroup_get_recursive_idx_stat(mem, MEM_CGROUP_STAT_CACHE);
3366 val += mem_cgroup_get_recursive_idx_stat(mem, MEM_CGROUP_STAT_RSS);
3368 if (swap)
3369 val += mem_cgroup_get_recursive_idx_stat(mem,
3370 MEM_CGROUP_STAT_SWAPOUT);
3372 return val << PAGE_SHIFT;
3375 static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft)
3377 struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
3378 u64 val;
3379 int type, name;
3381 type = MEMFILE_TYPE(cft->private);
3382 name = MEMFILE_ATTR(cft->private);
3383 switch (type) {
3384 case _MEM:
3385 if (name == RES_USAGE)
3386 val = mem_cgroup_usage(mem, false);
3387 else
3388 val = res_counter_read_u64(&mem->res, name);
3389 break;
3390 case _MEMSWAP:
3391 if (name == RES_USAGE)
3392 val = mem_cgroup_usage(mem, true);
3393 else
3394 val = res_counter_read_u64(&mem->memsw, name);
3395 break;
3396 default:
3397 BUG();
3398 break;
3400 return val;
3403 * The user of this function is...
3404 * RES_LIMIT.
3406 static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
3407 const char *buffer)
3409 struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
3410 int type, name;
3411 unsigned long long val;
3412 int ret;
3414 type = MEMFILE_TYPE(cft->private);
3415 name = MEMFILE_ATTR(cft->private);
3416 switch (name) {
3417 case RES_LIMIT:
3418 if (mem_cgroup_is_root(memcg)) { /* Can't set limit on root */
3419 ret = -EINVAL;
3420 break;
3422 /* This function does all necessary parse...reuse it */
3423 ret = res_counter_memparse_write_strategy(buffer, &val);
3424 if (ret)
3425 break;
3426 if (type == _MEM)
3427 ret = mem_cgroup_resize_limit(memcg, val);
3428 else
3429 ret = mem_cgroup_resize_memsw_limit(memcg, val);
3430 break;
3431 case RES_SOFT_LIMIT:
3432 ret = res_counter_memparse_write_strategy(buffer, &val);
3433 if (ret)
3434 break;
3436 * For memsw, soft limits are hard to implement in terms
3437 * of semantics, for now, we support soft limits for
3438 * control without swap
3440 if (type == _MEM)
3441 ret = res_counter_set_soft_limit(&memcg->res, val);
3442 else
3443 ret = -EINVAL;
3444 break;
3445 default:
3446 ret = -EINVAL; /* should be BUG() ? */
3447 break;
3449 return ret;
3452 static void memcg_get_hierarchical_limit(struct mem_cgroup *memcg,
3453 unsigned long long *mem_limit, unsigned long long *memsw_limit)
3455 struct cgroup *cgroup;
3456 unsigned long long min_limit, min_memsw_limit, tmp;
3458 min_limit = res_counter_read_u64(&memcg->res, RES_LIMIT);
3459 min_memsw_limit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
3460 cgroup = memcg->css.cgroup;
3461 if (!memcg->use_hierarchy)
3462 goto out;
3464 while (cgroup->parent) {
3465 cgroup = cgroup->parent;
3466 memcg = mem_cgroup_from_cont(cgroup);
3467 if (!memcg->use_hierarchy)
3468 break;
3469 tmp = res_counter_read_u64(&memcg->res, RES_LIMIT);
3470 min_limit = min(min_limit, tmp);
3471 tmp = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
3472 min_memsw_limit = min(min_memsw_limit, tmp);
3474 out:
3475 *mem_limit = min_limit;
3476 *memsw_limit = min_memsw_limit;
3477 return;
3480 static int mem_cgroup_reset(struct cgroup *cont, unsigned int event)
3482 struct mem_cgroup *mem;
3483 int type, name;
3485 mem = mem_cgroup_from_cont(cont);
3486 type = MEMFILE_TYPE(event);
3487 name = MEMFILE_ATTR(event);
3488 switch (name) {
3489 case RES_MAX_USAGE:
3490 if (type == _MEM)
3491 res_counter_reset_max(&mem->res);
3492 else
3493 res_counter_reset_max(&mem->memsw);
3494 break;
3495 case RES_FAILCNT:
3496 if (type == _MEM)
3497 res_counter_reset_failcnt(&mem->res);
3498 else
3499 res_counter_reset_failcnt(&mem->memsw);
3500 break;
3503 return 0;
3506 static u64 mem_cgroup_move_charge_read(struct cgroup *cgrp,
3507 struct cftype *cft)
3509 return mem_cgroup_from_cont(cgrp)->move_charge_at_immigrate;
3512 #ifdef CONFIG_MMU
3513 static int mem_cgroup_move_charge_write(struct cgroup *cgrp,
3514 struct cftype *cft, u64 val)
3516 struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp);
3518 if (val >= (1 << NR_MOVE_TYPE))
3519 return -EINVAL;
3521 * We check this value several times in both in can_attach() and
3522 * attach(), so we need cgroup lock to prevent this value from being
3523 * inconsistent.
3525 cgroup_lock();
3526 mem->move_charge_at_immigrate = val;
3527 cgroup_unlock();
3529 return 0;
3531 #else
3532 static int mem_cgroup_move_charge_write(struct cgroup *cgrp,
3533 struct cftype *cft, u64 val)
3535 return -ENOSYS;
3537 #endif
3540 /* For read statistics */
3541 enum {
3542 MCS_CACHE,
3543 MCS_RSS,
3544 MCS_FILE_MAPPED,
3545 MCS_PGPGIN,
3546 MCS_PGPGOUT,
3547 MCS_SWAP,
3548 MCS_INACTIVE_ANON,
3549 MCS_ACTIVE_ANON,
3550 MCS_INACTIVE_FILE,
3551 MCS_ACTIVE_FILE,
3552 MCS_UNEVICTABLE,
3553 NR_MCS_STAT,
3556 struct mcs_total_stat {
3557 s64 stat[NR_MCS_STAT];
3560 struct {
3561 char *local_name;
3562 char *total_name;
3563 } memcg_stat_strings[NR_MCS_STAT] = {
3564 {"cache", "total_cache"},
3565 {"rss", "total_rss"},
3566 {"mapped_file", "total_mapped_file"},
3567 {"pgpgin", "total_pgpgin"},
3568 {"pgpgout", "total_pgpgout"},
3569 {"swap", "total_swap"},
3570 {"inactive_anon", "total_inactive_anon"},
3571 {"active_anon", "total_active_anon"},
3572 {"inactive_file", "total_inactive_file"},
3573 {"active_file", "total_active_file"},
3574 {"unevictable", "total_unevictable"}
3578 static void
3579 mem_cgroup_get_local_stat(struct mem_cgroup *mem, struct mcs_total_stat *s)
3581 s64 val;
3583 /* per cpu stat */
3584 val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_CACHE);
3585 s->stat[MCS_CACHE] += val * PAGE_SIZE;
3586 val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_RSS);
3587 s->stat[MCS_RSS] += val * PAGE_SIZE;
3588 val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_FILE_MAPPED);
3589 s->stat[MCS_FILE_MAPPED] += val * PAGE_SIZE;
3590 val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_PGPGIN_COUNT);
3591 s->stat[MCS_PGPGIN] += val;
3592 val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_PGPGOUT_COUNT);
3593 s->stat[MCS_PGPGOUT] += val;
3594 if (do_swap_account) {
3595 val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_SWAPOUT);
3596 s->stat[MCS_SWAP] += val * PAGE_SIZE;
3599 /* per zone stat */
3600 val = mem_cgroup_get_local_zonestat(mem, LRU_INACTIVE_ANON);
3601 s->stat[MCS_INACTIVE_ANON] += val * PAGE_SIZE;
3602 val = mem_cgroup_get_local_zonestat(mem, LRU_ACTIVE_ANON);
3603 s->stat[MCS_ACTIVE_ANON] += val * PAGE_SIZE;
3604 val = mem_cgroup_get_local_zonestat(mem, LRU_INACTIVE_FILE);
3605 s->stat[MCS_INACTIVE_FILE] += val * PAGE_SIZE;
3606 val = mem_cgroup_get_local_zonestat(mem, LRU_ACTIVE_FILE);
3607 s->stat[MCS_ACTIVE_FILE] += val * PAGE_SIZE;
3608 val = mem_cgroup_get_local_zonestat(mem, LRU_UNEVICTABLE);
3609 s->stat[MCS_UNEVICTABLE] += val * PAGE_SIZE;
3612 static void
3613 mem_cgroup_get_total_stat(struct mem_cgroup *mem, struct mcs_total_stat *s)
3615 struct mem_cgroup *iter;
3617 for_each_mem_cgroup_tree(iter, mem)
3618 mem_cgroup_get_local_stat(iter, s);
3621 static int mem_control_stat_show(struct cgroup *cont, struct cftype *cft,
3622 struct cgroup_map_cb *cb)
3624 struct mem_cgroup *mem_cont = mem_cgroup_from_cont(cont);
3625 struct mcs_total_stat mystat;
3626 int i;
3628 memset(&mystat, 0, sizeof(mystat));
3629 mem_cgroup_get_local_stat(mem_cont, &mystat);
3631 for (i = 0; i < NR_MCS_STAT; i++) {
3632 if (i == MCS_SWAP && !do_swap_account)
3633 continue;
3634 cb->fill(cb, memcg_stat_strings[i].local_name, mystat.stat[i]);
3637 /* Hierarchical information */
3639 unsigned long long limit, memsw_limit;
3640 memcg_get_hierarchical_limit(mem_cont, &limit, &memsw_limit);
3641 cb->fill(cb, "hierarchical_memory_limit", limit);
3642 if (do_swap_account)
3643 cb->fill(cb, "hierarchical_memsw_limit", memsw_limit);
3646 memset(&mystat, 0, sizeof(mystat));
3647 mem_cgroup_get_total_stat(mem_cont, &mystat);
3648 for (i = 0; i < NR_MCS_STAT; i++) {
3649 if (i == MCS_SWAP && !do_swap_account)
3650 continue;
3651 cb->fill(cb, memcg_stat_strings[i].total_name, mystat.stat[i]);
3654 #ifdef CONFIG_DEBUG_VM
3655 cb->fill(cb, "inactive_ratio", calc_inactive_ratio(mem_cont, NULL));
3658 int nid, zid;
3659 struct mem_cgroup_per_zone *mz;
3660 unsigned long recent_rotated[2] = {0, 0};
3661 unsigned long recent_scanned[2] = {0, 0};
3663 for_each_online_node(nid)
3664 for (zid = 0; zid < MAX_NR_ZONES; zid++) {
3665 mz = mem_cgroup_zoneinfo(mem_cont, nid, zid);
3667 recent_rotated[0] +=
3668 mz->reclaim_stat.recent_rotated[0];
3669 recent_rotated[1] +=
3670 mz->reclaim_stat.recent_rotated[1];
3671 recent_scanned[0] +=
3672 mz->reclaim_stat.recent_scanned[0];
3673 recent_scanned[1] +=
3674 mz->reclaim_stat.recent_scanned[1];
3676 cb->fill(cb, "recent_rotated_anon", recent_rotated[0]);
3677 cb->fill(cb, "recent_rotated_file", recent_rotated[1]);
3678 cb->fill(cb, "recent_scanned_anon", recent_scanned[0]);
3679 cb->fill(cb, "recent_scanned_file", recent_scanned[1]);
3681 #endif
3683 return 0;
3686 static u64 mem_cgroup_swappiness_read(struct cgroup *cgrp, struct cftype *cft)
3688 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
3690 return get_swappiness(memcg);
3693 static int mem_cgroup_swappiness_write(struct cgroup *cgrp, struct cftype *cft,
3694 u64 val)
3696 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
3697 struct mem_cgroup *parent;
3699 if (val > 100)
3700 return -EINVAL;
3702 if (cgrp->parent == NULL)
3703 return -EINVAL;
3705 parent = mem_cgroup_from_cont(cgrp->parent);
3707 cgroup_lock();
3709 /* If under hierarchy, only empty-root can set this value */
3710 if ((parent->use_hierarchy) ||
3711 (memcg->use_hierarchy && !list_empty(&cgrp->children))) {
3712 cgroup_unlock();
3713 return -EINVAL;
3716 spin_lock(&memcg->reclaim_param_lock);
3717 memcg->swappiness = val;
3718 spin_unlock(&memcg->reclaim_param_lock);
3720 cgroup_unlock();
3722 return 0;
3725 static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap)
3727 struct mem_cgroup_threshold_ary *t;
3728 u64 usage;
3729 int i;
3731 rcu_read_lock();
3732 if (!swap)
3733 t = rcu_dereference(memcg->thresholds.primary);
3734 else
3735 t = rcu_dereference(memcg->memsw_thresholds.primary);
3737 if (!t)
3738 goto unlock;
3740 usage = mem_cgroup_usage(memcg, swap);
3743 * current_threshold points to threshold just below usage.
3744 * If it's not true, a threshold was crossed after last
3745 * call of __mem_cgroup_threshold().
3747 i = t->current_threshold;
3750 * Iterate backward over array of thresholds starting from
3751 * current_threshold and check if a threshold is crossed.
3752 * If none of thresholds below usage is crossed, we read
3753 * only one element of the array here.
3755 for (; i >= 0 && unlikely(t->entries[i].threshold > usage); i--)
3756 eventfd_signal(t->entries[i].eventfd, 1);
3758 /* i = current_threshold + 1 */
3759 i++;
3762 * Iterate forward over array of thresholds starting from
3763 * current_threshold+1 and check if a threshold is crossed.
3764 * If none of thresholds above usage is crossed, we read
3765 * only one element of the array here.
3767 for (; i < t->size && unlikely(t->entries[i].threshold <= usage); i++)
3768 eventfd_signal(t->entries[i].eventfd, 1);
3770 /* Update current_threshold */
3771 t->current_threshold = i - 1;
3772 unlock:
3773 rcu_read_unlock();
3776 static void mem_cgroup_threshold(struct mem_cgroup *memcg)
3778 while (memcg) {
3779 __mem_cgroup_threshold(memcg, false);
3780 if (do_swap_account)
3781 __mem_cgroup_threshold(memcg, true);
3783 memcg = parent_mem_cgroup(memcg);
3787 static int compare_thresholds(const void *a, const void *b)
3789 const struct mem_cgroup_threshold *_a = a;
3790 const struct mem_cgroup_threshold *_b = b;
3792 return _a->threshold - _b->threshold;
3795 static int mem_cgroup_oom_notify_cb(struct mem_cgroup *mem)
3797 struct mem_cgroup_eventfd_list *ev;
3799 list_for_each_entry(ev, &mem->oom_notify, list)
3800 eventfd_signal(ev->eventfd, 1);
3801 return 0;
3804 static void mem_cgroup_oom_notify(struct mem_cgroup *mem)
3806 struct mem_cgroup *iter;
3808 for_each_mem_cgroup_tree(iter, mem)
3809 mem_cgroup_oom_notify_cb(iter);
3812 static int mem_cgroup_usage_register_event(struct cgroup *cgrp,
3813 struct cftype *cft, struct eventfd_ctx *eventfd, const char *args)
3815 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
3816 struct mem_cgroup_thresholds *thresholds;
3817 struct mem_cgroup_threshold_ary *new;
3818 int type = MEMFILE_TYPE(cft->private);
3819 u64 threshold, usage;
3820 int i, size, ret;
3822 ret = res_counter_memparse_write_strategy(args, &threshold);
3823 if (ret)
3824 return ret;
3826 mutex_lock(&memcg->thresholds_lock);
3828 if (type == _MEM)
3829 thresholds = &memcg->thresholds;
3830 else if (type == _MEMSWAP)
3831 thresholds = &memcg->memsw_thresholds;
3832 else
3833 BUG();
3835 usage = mem_cgroup_usage(memcg, type == _MEMSWAP);
3837 /* Check if a threshold crossed before adding a new one */
3838 if (thresholds->primary)
3839 __mem_cgroup_threshold(memcg, type == _MEMSWAP);
3841 size = thresholds->primary ? thresholds->primary->size + 1 : 1;
3843 /* Allocate memory for new array of thresholds */
3844 new = kmalloc(sizeof(*new) + size * sizeof(struct mem_cgroup_threshold),
3845 GFP_KERNEL);
3846 if (!new) {
3847 ret = -ENOMEM;
3848 goto unlock;
3850 new->size = size;
3852 /* Copy thresholds (if any) to new array */
3853 if (thresholds->primary) {
3854 memcpy(new->entries, thresholds->primary->entries, (size - 1) *
3855 sizeof(struct mem_cgroup_threshold));
3858 /* Add new threshold */
3859 new->entries[size - 1].eventfd = eventfd;
3860 new->entries[size - 1].threshold = threshold;
3862 /* Sort thresholds. Registering of new threshold isn't time-critical */
3863 sort(new->entries, size, sizeof(struct mem_cgroup_threshold),
3864 compare_thresholds, NULL);
3866 /* Find current threshold */
3867 new->current_threshold = -1;
3868 for (i = 0; i < size; i++) {
3869 if (new->entries[i].threshold < usage) {
3871 * new->current_threshold will not be used until
3872 * rcu_assign_pointer(), so it's safe to increment
3873 * it here.
3875 ++new->current_threshold;
3879 /* Free old spare buffer and save old primary buffer as spare */
3880 kfree(thresholds->spare);
3881 thresholds->spare = thresholds->primary;
3883 rcu_assign_pointer(thresholds->primary, new);
3885 /* To be sure that nobody uses thresholds */
3886 synchronize_rcu();
3888 unlock:
3889 mutex_unlock(&memcg->thresholds_lock);
3891 return ret;
3894 static void mem_cgroup_usage_unregister_event(struct cgroup *cgrp,
3895 struct cftype *cft, struct eventfd_ctx *eventfd)
3897 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
3898 struct mem_cgroup_thresholds *thresholds;
3899 struct mem_cgroup_threshold_ary *new;
3900 int type = MEMFILE_TYPE(cft->private);
3901 u64 usage;
3902 int i, j, size;
3904 mutex_lock(&memcg->thresholds_lock);
3905 if (type == _MEM)
3906 thresholds = &memcg->thresholds;
3907 else if (type == _MEMSWAP)
3908 thresholds = &memcg->memsw_thresholds;
3909 else
3910 BUG();
3913 * Something went wrong if we trying to unregister a threshold
3914 * if we don't have thresholds
3916 BUG_ON(!thresholds);
3918 usage = mem_cgroup_usage(memcg, type == _MEMSWAP);
3920 /* Check if a threshold crossed before removing */
3921 __mem_cgroup_threshold(memcg, type == _MEMSWAP);
3923 /* Calculate new number of threshold */
3924 size = 0;
3925 for (i = 0; i < thresholds->primary->size; i++) {
3926 if (thresholds->primary->entries[i].eventfd != eventfd)
3927 size++;
3930 new = thresholds->spare;
3932 /* Set thresholds array to NULL if we don't have thresholds */
3933 if (!size) {
3934 kfree(new);
3935 new = NULL;
3936 goto swap_buffers;
3939 new->size = size;
3941 /* Copy thresholds and find current threshold */
3942 new->current_threshold = -1;
3943 for (i = 0, j = 0; i < thresholds->primary->size; i++) {
3944 if (thresholds->primary->entries[i].eventfd == eventfd)
3945 continue;
3947 new->entries[j] = thresholds->primary->entries[i];
3948 if (new->entries[j].threshold < usage) {
3950 * new->current_threshold will not be used
3951 * until rcu_assign_pointer(), so it's safe to increment
3952 * it here.
3954 ++new->current_threshold;
3956 j++;
3959 swap_buffers:
3960 /* Swap primary and spare array */
3961 thresholds->spare = thresholds->primary;
3962 rcu_assign_pointer(thresholds->primary, new);
3964 /* To be sure that nobody uses thresholds */
3965 synchronize_rcu();
3967 mutex_unlock(&memcg->thresholds_lock);
3970 static int mem_cgroup_oom_register_event(struct cgroup *cgrp,
3971 struct cftype *cft, struct eventfd_ctx *eventfd, const char *args)
3973 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
3974 struct mem_cgroup_eventfd_list *event;
3975 int type = MEMFILE_TYPE(cft->private);
3977 BUG_ON(type != _OOM_TYPE);
3978 event = kmalloc(sizeof(*event), GFP_KERNEL);
3979 if (!event)
3980 return -ENOMEM;
3982 mutex_lock(&memcg_oom_mutex);
3984 event->eventfd = eventfd;
3985 list_add(&event->list, &memcg->oom_notify);
3987 /* already in OOM ? */
3988 if (atomic_read(&memcg->oom_lock))
3989 eventfd_signal(eventfd, 1);
3990 mutex_unlock(&memcg_oom_mutex);
3992 return 0;
3995 static void mem_cgroup_oom_unregister_event(struct cgroup *cgrp,
3996 struct cftype *cft, struct eventfd_ctx *eventfd)
3998 struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp);
3999 struct mem_cgroup_eventfd_list *ev, *tmp;
4000 int type = MEMFILE_TYPE(cft->private);
4002 BUG_ON(type != _OOM_TYPE);
4004 mutex_lock(&memcg_oom_mutex);
4006 list_for_each_entry_safe(ev, tmp, &mem->oom_notify, list) {
4007 if (ev->eventfd == eventfd) {
4008 list_del(&ev->list);
4009 kfree(ev);
4013 mutex_unlock(&memcg_oom_mutex);
4016 static int mem_cgroup_oom_control_read(struct cgroup *cgrp,
4017 struct cftype *cft, struct cgroup_map_cb *cb)
4019 struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp);
4021 cb->fill(cb, "oom_kill_disable", mem->oom_kill_disable);
4023 if (atomic_read(&mem->oom_lock))
4024 cb->fill(cb, "under_oom", 1);
4025 else
4026 cb->fill(cb, "under_oom", 0);
4027 return 0;
4030 static int mem_cgroup_oom_control_write(struct cgroup *cgrp,
4031 struct cftype *cft, u64 val)
4033 struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp);
4034 struct mem_cgroup *parent;
4036 /* cannot set to root cgroup and only 0 and 1 are allowed */
4037 if (!cgrp->parent || !((val == 0) || (val == 1)))
4038 return -EINVAL;
4040 parent = mem_cgroup_from_cont(cgrp->parent);
4042 cgroup_lock();
4043 /* oom-kill-disable is a flag for subhierarchy. */
4044 if ((parent->use_hierarchy) ||
4045 (mem->use_hierarchy && !list_empty(&cgrp->children))) {
4046 cgroup_unlock();
4047 return -EINVAL;
4049 mem->oom_kill_disable = val;
4050 if (!val)
4051 memcg_oom_recover(mem);
4052 cgroup_unlock();
4053 return 0;
4056 static struct cftype mem_cgroup_files[] = {
4058 .name = "usage_in_bytes",
4059 .private = MEMFILE_PRIVATE(_MEM, RES_USAGE),
4060 .read_u64 = mem_cgroup_read,
4061 .register_event = mem_cgroup_usage_register_event,
4062 .unregister_event = mem_cgroup_usage_unregister_event,
4065 .name = "max_usage_in_bytes",
4066 .private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE),
4067 .trigger = mem_cgroup_reset,
4068 .read_u64 = mem_cgroup_read,
4071 .name = "limit_in_bytes",
4072 .private = MEMFILE_PRIVATE(_MEM, RES_LIMIT),
4073 .write_string = mem_cgroup_write,
4074 .read_u64 = mem_cgroup_read,
4077 .name = "soft_limit_in_bytes",
4078 .private = MEMFILE_PRIVATE(_MEM, RES_SOFT_LIMIT),
4079 .write_string = mem_cgroup_write,
4080 .read_u64 = mem_cgroup_read,
4083 .name = "failcnt",
4084 .private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT),
4085 .trigger = mem_cgroup_reset,
4086 .read_u64 = mem_cgroup_read,
4089 .name = "stat",
4090 .read_map = mem_control_stat_show,
4093 .name = "force_empty",
4094 .trigger = mem_cgroup_force_empty_write,
4097 .name = "use_hierarchy",
4098 .write_u64 = mem_cgroup_hierarchy_write,
4099 .read_u64 = mem_cgroup_hierarchy_read,
4102 .name = "swappiness",
4103 .read_u64 = mem_cgroup_swappiness_read,
4104 .write_u64 = mem_cgroup_swappiness_write,
4107 .name = "move_charge_at_immigrate",
4108 .read_u64 = mem_cgroup_move_charge_read,
4109 .write_u64 = mem_cgroup_move_charge_write,
4112 .name = "oom_control",
4113 .read_map = mem_cgroup_oom_control_read,
4114 .write_u64 = mem_cgroup_oom_control_write,
4115 .register_event = mem_cgroup_oom_register_event,
4116 .unregister_event = mem_cgroup_oom_unregister_event,
4117 .private = MEMFILE_PRIVATE(_OOM_TYPE, OOM_CONTROL),
4121 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
4122 static struct cftype memsw_cgroup_files[] = {
4124 .name = "memsw.usage_in_bytes",
4125 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE),
4126 .read_u64 = mem_cgroup_read,
4127 .register_event = mem_cgroup_usage_register_event,
4128 .unregister_event = mem_cgroup_usage_unregister_event,
4131 .name = "memsw.max_usage_in_bytes",
4132 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE),
4133 .trigger = mem_cgroup_reset,
4134 .read_u64 = mem_cgroup_read,
4137 .name = "memsw.limit_in_bytes",
4138 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT),
4139 .write_string = mem_cgroup_write,
4140 .read_u64 = mem_cgroup_read,
4143 .name = "memsw.failcnt",
4144 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT),
4145 .trigger = mem_cgroup_reset,
4146 .read_u64 = mem_cgroup_read,
4150 static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss)
4152 if (!do_swap_account)
4153 return 0;
4154 return cgroup_add_files(cont, ss, memsw_cgroup_files,
4155 ARRAY_SIZE(memsw_cgroup_files));
4157 #else
4158 static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss)
4160 return 0;
4162 #endif
4164 static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
4166 struct mem_cgroup_per_node *pn;
4167 struct mem_cgroup_per_zone *mz;
4168 enum lru_list l;
4169 int zone, tmp = node;
4171 * This routine is called against possible nodes.
4172 * But it's BUG to call kmalloc() against offline node.
4174 * TODO: this routine can waste much memory for nodes which will
4175 * never be onlined. It's better to use memory hotplug callback
4176 * function.
4178 if (!node_state(node, N_NORMAL_MEMORY))
4179 tmp = -1;
4180 pn = kmalloc_node(sizeof(*pn), GFP_KERNEL, tmp);
4181 if (!pn)
4182 return 1;
4184 mem->info.nodeinfo[node] = pn;
4185 memset(pn, 0, sizeof(*pn));
4187 for (zone = 0; zone < MAX_NR_ZONES; zone++) {
4188 mz = &pn->zoneinfo[zone];
4189 for_each_lru(l)
4190 INIT_LIST_HEAD(&mz->lists[l]);
4191 mz->usage_in_excess = 0;
4192 mz->on_tree = false;
4193 mz->mem = mem;
4195 return 0;
4198 static void free_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
4200 kfree(mem->info.nodeinfo[node]);
4203 static struct mem_cgroup *mem_cgroup_alloc(void)
4205 struct mem_cgroup *mem;
4206 int size = sizeof(struct mem_cgroup);
4208 /* Can be very big if MAX_NUMNODES is very big */
4209 if (size < PAGE_SIZE)
4210 mem = kmalloc(size, GFP_KERNEL);
4211 else
4212 mem = vmalloc(size);
4214 if (!mem)
4215 return NULL;
4217 memset(mem, 0, size);
4218 mem->stat = alloc_percpu(struct mem_cgroup_stat_cpu);
4219 if (!mem->stat)
4220 goto out_free;
4221 spin_lock_init(&mem->pcp_counter_lock);
4222 return mem;
4224 out_free:
4225 if (size < PAGE_SIZE)
4226 kfree(mem);
4227 else
4228 vfree(mem);
4229 return NULL;
4233 * At destroying mem_cgroup, references from swap_cgroup can remain.
4234 * (scanning all at force_empty is too costly...)
4236 * Instead of clearing all references at force_empty, we remember
4237 * the number of reference from swap_cgroup and free mem_cgroup when
4238 * it goes down to 0.
4240 * Removal of cgroup itself succeeds regardless of refs from swap.
4243 static void __mem_cgroup_free(struct mem_cgroup *mem)
4245 int node;
4247 mem_cgroup_remove_from_trees(mem);
4248 free_css_id(&mem_cgroup_subsys, &mem->css);
4250 for_each_node_state(node, N_POSSIBLE)
4251 free_mem_cgroup_per_zone_info(mem, node);
4253 free_percpu(mem->stat);
4254 if (sizeof(struct mem_cgroup) < PAGE_SIZE)
4255 kfree(mem);
4256 else
4257 vfree(mem);
4260 static void mem_cgroup_get(struct mem_cgroup *mem)
4262 atomic_inc(&mem->refcnt);
4265 static void __mem_cgroup_put(struct mem_cgroup *mem, int count)
4267 if (atomic_sub_and_test(count, &mem->refcnt)) {
4268 struct mem_cgroup *parent = parent_mem_cgroup(mem);
4269 __mem_cgroup_free(mem);
4270 if (parent)
4271 mem_cgroup_put(parent);
4275 static void mem_cgroup_put(struct mem_cgroup *mem)
4277 __mem_cgroup_put(mem, 1);
4281 * Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled.
4283 static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem)
4285 if (!mem->res.parent)
4286 return NULL;
4287 return mem_cgroup_from_res_counter(mem->res.parent, res);
4290 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
4291 static void __init enable_swap_cgroup(void)
4293 if (!mem_cgroup_disabled() && really_do_swap_account)
4294 do_swap_account = 1;
4296 #else
4297 static void __init enable_swap_cgroup(void)
4300 #endif
4302 static int mem_cgroup_soft_limit_tree_init(void)
4304 struct mem_cgroup_tree_per_node *rtpn;
4305 struct mem_cgroup_tree_per_zone *rtpz;
4306 int tmp, node, zone;
4308 for_each_node_state(node, N_POSSIBLE) {
4309 tmp = node;
4310 if (!node_state(node, N_NORMAL_MEMORY))
4311 tmp = -1;
4312 rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL, tmp);
4313 if (!rtpn)
4314 return 1;
4316 soft_limit_tree.rb_tree_per_node[node] = rtpn;
4318 for (zone = 0; zone < MAX_NR_ZONES; zone++) {
4319 rtpz = &rtpn->rb_tree_per_zone[zone];
4320 rtpz->rb_root = RB_ROOT;
4321 spin_lock_init(&rtpz->lock);
4324 return 0;
4327 static struct cgroup_subsys_state * __ref
4328 mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
4330 struct mem_cgroup *mem, *parent;
4331 long error = -ENOMEM;
4332 int node;
4334 mem = mem_cgroup_alloc();
4335 if (!mem)
4336 return ERR_PTR(error);
4338 for_each_node_state(node, N_POSSIBLE)
4339 if (alloc_mem_cgroup_per_zone_info(mem, node))
4340 goto free_out;
4342 /* root ? */
4343 if (cont->parent == NULL) {
4344 int cpu;
4345 enable_swap_cgroup();
4346 parent = NULL;
4347 root_mem_cgroup = mem;
4348 if (mem_cgroup_soft_limit_tree_init())
4349 goto free_out;
4350 for_each_possible_cpu(cpu) {
4351 struct memcg_stock_pcp *stock =
4352 &per_cpu(memcg_stock, cpu);
4353 INIT_WORK(&stock->work, drain_local_stock);
4355 hotcpu_notifier(memcg_cpu_hotplug_callback, 0);
4356 } else {
4357 parent = mem_cgroup_from_cont(cont->parent);
4358 mem->use_hierarchy = parent->use_hierarchy;
4359 mem->oom_kill_disable = parent->oom_kill_disable;
4362 if (parent && parent->use_hierarchy) {
4363 res_counter_init(&mem->res, &parent->res);
4364 res_counter_init(&mem->memsw, &parent->memsw);
4366 * We increment refcnt of the parent to ensure that we can
4367 * safely access it on res_counter_charge/uncharge.
4368 * This refcnt will be decremented when freeing this
4369 * mem_cgroup(see mem_cgroup_put).
4371 mem_cgroup_get(parent);
4372 } else {
4373 res_counter_init(&mem->res, NULL);
4374 res_counter_init(&mem->memsw, NULL);
4376 mem->last_scanned_child = 0;
4377 spin_lock_init(&mem->reclaim_param_lock);
4378 INIT_LIST_HEAD(&mem->oom_notify);
4380 if (parent)
4381 mem->swappiness = get_swappiness(parent);
4382 atomic_set(&mem->refcnt, 1);
4383 mem->move_charge_at_immigrate = 0;
4384 mutex_init(&mem->thresholds_lock);
4385 return &mem->css;
4386 free_out:
4387 __mem_cgroup_free(mem);
4388 root_mem_cgroup = NULL;
4389 return ERR_PTR(error);
4392 static int mem_cgroup_pre_destroy(struct cgroup_subsys *ss,
4393 struct cgroup *cont)
4395 struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
4397 return mem_cgroup_force_empty(mem, false);
4400 static void mem_cgroup_destroy(struct cgroup_subsys *ss,
4401 struct cgroup *cont)
4403 struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
4405 mem_cgroup_put(mem);
4408 static int mem_cgroup_populate(struct cgroup_subsys *ss,
4409 struct cgroup *cont)
4411 int ret;
4413 ret = cgroup_add_files(cont, ss, mem_cgroup_files,
4414 ARRAY_SIZE(mem_cgroup_files));
4416 if (!ret)
4417 ret = register_memsw_files(cont, ss);
4418 return ret;
4421 #ifdef CONFIG_MMU
4422 /* Handlers for move charge at task migration. */
4423 #define PRECHARGE_COUNT_AT_ONCE 256
4424 static int mem_cgroup_do_precharge(unsigned long count)
4426 int ret = 0;
4427 int batch_count = PRECHARGE_COUNT_AT_ONCE;
4428 struct mem_cgroup *mem = mc.to;
4430 if (mem_cgroup_is_root(mem)) {
4431 mc.precharge += count;
4432 /* we don't need css_get for root */
4433 return ret;
4435 /* try to charge at once */
4436 if (count > 1) {
4437 struct res_counter *dummy;
4439 * "mem" cannot be under rmdir() because we've already checked
4440 * by cgroup_lock_live_cgroup() that it is not removed and we
4441 * are still under the same cgroup_mutex. So we can postpone
4442 * css_get().
4444 if (res_counter_charge(&mem->res, PAGE_SIZE * count, &dummy))
4445 goto one_by_one;
4446 if (do_swap_account && res_counter_charge(&mem->memsw,
4447 PAGE_SIZE * count, &dummy)) {
4448 res_counter_uncharge(&mem->res, PAGE_SIZE * count);
4449 goto one_by_one;
4451 mc.precharge += count;
4452 return ret;
4454 one_by_one:
4455 /* fall back to one by one charge */
4456 while (count--) {
4457 if (signal_pending(current)) {
4458 ret = -EINTR;
4459 break;
4461 if (!batch_count--) {
4462 batch_count = PRECHARGE_COUNT_AT_ONCE;
4463 cond_resched();
4465 ret = __mem_cgroup_try_charge(NULL, GFP_KERNEL, &mem, false);
4466 if (ret || !mem)
4467 /* mem_cgroup_clear_mc() will do uncharge later */
4468 return -ENOMEM;
4469 mc.precharge++;
4471 return ret;
4475 * is_target_pte_for_mc - check a pte whether it is valid for move charge
4476 * @vma: the vma the pte to be checked belongs
4477 * @addr: the address corresponding to the pte to be checked
4478 * @ptent: the pte to be checked
4479 * @target: the pointer the target page or swap ent will be stored(can be NULL)
4481 * Returns
4482 * 0(MC_TARGET_NONE): if the pte is not a target for move charge.
4483 * 1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for
4484 * move charge. if @target is not NULL, the page is stored in target->page
4485 * with extra refcnt got(Callers should handle it).
4486 * 2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a
4487 * target for charge migration. if @target is not NULL, the entry is stored
4488 * in target->ent.
4490 * Called with pte lock held.
4492 union mc_target {
4493 struct page *page;
4494 swp_entry_t ent;
4497 enum mc_target_type {
4498 MC_TARGET_NONE, /* not used */
4499 MC_TARGET_PAGE,
4500 MC_TARGET_SWAP,
4503 static struct page *mc_handle_present_pte(struct vm_area_struct *vma,
4504 unsigned long addr, pte_t ptent)
4506 struct page *page = vm_normal_page(vma, addr, ptent);
4508 if (!page || !page_mapped(page))
4509 return NULL;
4510 if (PageAnon(page)) {
4511 /* we don't move shared anon */
4512 if (!move_anon() || page_mapcount(page) > 2)
4513 return NULL;
4514 } else if (!move_file())
4515 /* we ignore mapcount for file pages */
4516 return NULL;
4517 if (!get_page_unless_zero(page))
4518 return NULL;
4520 return page;
4523 static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
4524 unsigned long addr, pte_t ptent, swp_entry_t *entry)
4526 int usage_count;
4527 struct page *page = NULL;
4528 swp_entry_t ent = pte_to_swp_entry(ptent);
4530 if (!move_anon() || non_swap_entry(ent))
4531 return NULL;
4532 usage_count = mem_cgroup_count_swap_user(ent, &page);
4533 if (usage_count > 1) { /* we don't move shared anon */
4534 if (page)
4535 put_page(page);
4536 return NULL;
4538 if (do_swap_account)
4539 entry->val = ent.val;
4541 return page;
4544 static struct page *mc_handle_file_pte(struct vm_area_struct *vma,
4545 unsigned long addr, pte_t ptent, swp_entry_t *entry)
4547 struct page *page = NULL;
4548 struct inode *inode;
4549 struct address_space *mapping;
4550 pgoff_t pgoff;
4552 if (!vma->vm_file) /* anonymous vma */
4553 return NULL;
4554 if (!move_file())
4555 return NULL;
4557 inode = vma->vm_file->f_path.dentry->d_inode;
4558 mapping = vma->vm_file->f_mapping;
4559 if (pte_none(ptent))
4560 pgoff = linear_page_index(vma, addr);
4561 else /* pte_file(ptent) is true */
4562 pgoff = pte_to_pgoff(ptent);
4564 /* page is moved even if it's not RSS of this task(page-faulted). */
4565 if (!mapping_cap_swap_backed(mapping)) { /* normal file */
4566 page = find_get_page(mapping, pgoff);
4567 } else { /* shmem/tmpfs file. we should take account of swap too. */
4568 swp_entry_t ent;
4569 mem_cgroup_get_shmem_target(inode, pgoff, &page, &ent);
4570 if (do_swap_account)
4571 entry->val = ent.val;
4574 return page;
4577 static int is_target_pte_for_mc(struct vm_area_struct *vma,
4578 unsigned long addr, pte_t ptent, union mc_target *target)
4580 struct page *page = NULL;
4581 struct page_cgroup *pc;
4582 int ret = 0;
4583 swp_entry_t ent = { .val = 0 };
4585 if (pte_present(ptent))
4586 page = mc_handle_present_pte(vma, addr, ptent);
4587 else if (is_swap_pte(ptent))
4588 page = mc_handle_swap_pte(vma, addr, ptent, &ent);
4589 else if (pte_none(ptent) || pte_file(ptent))
4590 page = mc_handle_file_pte(vma, addr, ptent, &ent);
4592 if (!page && !ent.val)
4593 return 0;
4594 if (page) {
4595 pc = lookup_page_cgroup(page);
4597 * Do only loose check w/o page_cgroup lock.
4598 * mem_cgroup_move_account() checks the pc is valid or not under
4599 * the lock.
4601 if (PageCgroupUsed(pc) && pc->mem_cgroup == mc.from) {
4602 ret = MC_TARGET_PAGE;
4603 if (target)
4604 target->page = page;
4606 if (!ret || !target)
4607 put_page(page);
4609 /* There is a swap entry and a page doesn't exist or isn't charged */
4610 if (ent.val && !ret &&
4611 css_id(&mc.from->css) == lookup_swap_cgroup(ent)) {
4612 ret = MC_TARGET_SWAP;
4613 if (target)
4614 target->ent = ent;
4616 return ret;
4619 static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd,
4620 unsigned long addr, unsigned long end,
4621 struct mm_walk *walk)
4623 struct vm_area_struct *vma = walk->private;
4624 pte_t *pte;
4625 spinlock_t *ptl;
4627 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
4628 for (; addr != end; pte++, addr += PAGE_SIZE)
4629 if (is_target_pte_for_mc(vma, addr, *pte, NULL))
4630 mc.precharge++; /* increment precharge temporarily */
4631 pte_unmap_unlock(pte - 1, ptl);
4632 cond_resched();
4634 return 0;
4637 static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm)
4639 unsigned long precharge;
4640 struct vm_area_struct *vma;
4642 /* We've already held the mmap_sem */
4643 for (vma = mm->mmap; vma; vma = vma->vm_next) {
4644 struct mm_walk mem_cgroup_count_precharge_walk = {
4645 .pmd_entry = mem_cgroup_count_precharge_pte_range,
4646 .mm = mm,
4647 .private = vma,
4649 if (is_vm_hugetlb_page(vma))
4650 continue;
4651 walk_page_range(vma->vm_start, vma->vm_end,
4652 &mem_cgroup_count_precharge_walk);
4655 precharge = mc.precharge;
4656 mc.precharge = 0;
4658 return precharge;
4661 static int mem_cgroup_precharge_mc(struct mm_struct *mm)
4663 return mem_cgroup_do_precharge(mem_cgroup_count_precharge(mm));
4666 static void mem_cgroup_clear_mc(void)
4668 struct mem_cgroup *from = mc.from;
4669 struct mem_cgroup *to = mc.to;
4671 /* we must uncharge all the leftover precharges from mc.to */
4672 if (mc.precharge) {
4673 __mem_cgroup_cancel_charge(mc.to, mc.precharge);
4674 mc.precharge = 0;
4677 * we didn't uncharge from mc.from at mem_cgroup_move_account(), so
4678 * we must uncharge here.
4680 if (mc.moved_charge) {
4681 __mem_cgroup_cancel_charge(mc.from, mc.moved_charge);
4682 mc.moved_charge = 0;
4684 /* we must fixup refcnts and charges */
4685 if (mc.moved_swap) {
4686 /* uncharge swap account from the old cgroup */
4687 if (!mem_cgroup_is_root(mc.from))
4688 res_counter_uncharge(&mc.from->memsw,
4689 PAGE_SIZE * mc.moved_swap);
4690 __mem_cgroup_put(mc.from, mc.moved_swap);
4692 if (!mem_cgroup_is_root(mc.to)) {
4694 * we charged both to->res and to->memsw, so we should
4695 * uncharge to->res.
4697 res_counter_uncharge(&mc.to->res,
4698 PAGE_SIZE * mc.moved_swap);
4700 /* we've already done mem_cgroup_get(mc.to) */
4702 mc.moved_swap = 0;
4704 if (mc.mm) {
4705 up_read(&mc.mm->mmap_sem);
4706 mmput(mc.mm);
4708 spin_lock(&mc.lock);
4709 mc.from = NULL;
4710 mc.to = NULL;
4711 spin_unlock(&mc.lock);
4712 mc.moving_task = NULL;
4713 mc.mm = NULL;
4714 mem_cgroup_end_move(from);
4715 memcg_oom_recover(from);
4716 memcg_oom_recover(to);
4717 wake_up_all(&mc.waitq);
4720 static int mem_cgroup_can_attach(struct cgroup_subsys *ss,
4721 struct cgroup *cgroup,
4722 struct task_struct *p,
4723 bool threadgroup)
4725 int ret = 0;
4726 struct mem_cgroup *mem = mem_cgroup_from_cont(cgroup);
4728 if (mem->move_charge_at_immigrate) {
4729 struct mm_struct *mm;
4730 struct mem_cgroup *from = mem_cgroup_from_task(p);
4732 VM_BUG_ON(from == mem);
4734 mm = get_task_mm(p);
4735 if (!mm)
4736 return 0;
4737 /* We move charges only when we move a owner of the mm */
4738 if (mm->owner == p) {
4740 * We do all the move charge works under one mmap_sem to
4741 * avoid deadlock with down_write(&mmap_sem)
4742 * -> try_charge() -> if (mc.moving_task) -> sleep.
4744 down_read(&mm->mmap_sem);
4746 VM_BUG_ON(mc.from);
4747 VM_BUG_ON(mc.to);
4748 VM_BUG_ON(mc.precharge);
4749 VM_BUG_ON(mc.moved_charge);
4750 VM_BUG_ON(mc.moved_swap);
4751 VM_BUG_ON(mc.moving_task);
4752 VM_BUG_ON(mc.mm);
4754 mem_cgroup_start_move(from);
4755 spin_lock(&mc.lock);
4756 mc.from = from;
4757 mc.to = mem;
4758 mc.precharge = 0;
4759 mc.moved_charge = 0;
4760 mc.moved_swap = 0;
4761 spin_unlock(&mc.lock);
4762 mc.moving_task = current;
4763 mc.mm = mm;
4765 ret = mem_cgroup_precharge_mc(mm);
4766 if (ret)
4767 mem_cgroup_clear_mc();
4768 /* We call up_read() and mmput() in clear_mc(). */
4769 } else
4770 mmput(mm);
4772 return ret;
4775 static void mem_cgroup_cancel_attach(struct cgroup_subsys *ss,
4776 struct cgroup *cgroup,
4777 struct task_struct *p,
4778 bool threadgroup)
4780 mem_cgroup_clear_mc();
4783 static int mem_cgroup_move_charge_pte_range(pmd_t *pmd,
4784 unsigned long addr, unsigned long end,
4785 struct mm_walk *walk)
4787 int ret = 0;
4788 struct vm_area_struct *vma = walk->private;
4789 pte_t *pte;
4790 spinlock_t *ptl;
4792 retry:
4793 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
4794 for (; addr != end; addr += PAGE_SIZE) {
4795 pte_t ptent = *(pte++);
4796 union mc_target target;
4797 int type;
4798 struct page *page;
4799 struct page_cgroup *pc;
4800 swp_entry_t ent;
4802 if (!mc.precharge)
4803 break;
4805 type = is_target_pte_for_mc(vma, addr, ptent, &target);
4806 switch (type) {
4807 case MC_TARGET_PAGE:
4808 page = target.page;
4809 if (isolate_lru_page(page))
4810 goto put;
4811 pc = lookup_page_cgroup(page);
4812 if (!mem_cgroup_move_account(pc,
4813 mc.from, mc.to, false)) {
4814 mc.precharge--;
4815 /* we uncharge from mc.from later. */
4816 mc.moved_charge++;
4818 putback_lru_page(page);
4819 put: /* is_target_pte_for_mc() gets the page */
4820 put_page(page);
4821 break;
4822 case MC_TARGET_SWAP:
4823 ent = target.ent;
4824 if (!mem_cgroup_move_swap_account(ent,
4825 mc.from, mc.to, false)) {
4826 mc.precharge--;
4827 /* we fixup refcnts and charges later. */
4828 mc.moved_swap++;
4830 break;
4831 default:
4832 break;
4835 pte_unmap_unlock(pte - 1, ptl);
4836 cond_resched();
4838 if (addr != end) {
4840 * We have consumed all precharges we got in can_attach().
4841 * We try charge one by one, but don't do any additional
4842 * charges to mc.to if we have failed in charge once in attach()
4843 * phase.
4845 ret = mem_cgroup_do_precharge(1);
4846 if (!ret)
4847 goto retry;
4850 return ret;
4853 static void mem_cgroup_move_charge(struct mm_struct *mm)
4855 struct vm_area_struct *vma;
4857 lru_add_drain_all();
4858 /* We've already held the mmap_sem */
4859 for (vma = mm->mmap; vma; vma = vma->vm_next) {
4860 int ret;
4861 struct mm_walk mem_cgroup_move_charge_walk = {
4862 .pmd_entry = mem_cgroup_move_charge_pte_range,
4863 .mm = mm,
4864 .private = vma,
4866 if (is_vm_hugetlb_page(vma))
4867 continue;
4868 ret = walk_page_range(vma->vm_start, vma->vm_end,
4869 &mem_cgroup_move_charge_walk);
4870 if (ret)
4872 * means we have consumed all precharges and failed in
4873 * doing additional charge. Just abandon here.
4875 break;
4879 static void mem_cgroup_move_task(struct cgroup_subsys *ss,
4880 struct cgroup *cont,
4881 struct cgroup *old_cont,
4882 struct task_struct *p,
4883 bool threadgroup)
4885 if (!mc.mm)
4886 /* no need to move charge */
4887 return;
4889 mem_cgroup_move_charge(mc.mm);
4890 mem_cgroup_clear_mc();
4892 #else /* !CONFIG_MMU */
4893 static int mem_cgroup_can_attach(struct cgroup_subsys *ss,
4894 struct cgroup *cgroup,
4895 struct task_struct *p,
4896 bool threadgroup)
4898 return 0;
4900 static void mem_cgroup_cancel_attach(struct cgroup_subsys *ss,
4901 struct cgroup *cgroup,
4902 struct task_struct *p,
4903 bool threadgroup)
4906 static void mem_cgroup_move_task(struct cgroup_subsys *ss,
4907 struct cgroup *cont,
4908 struct cgroup *old_cont,
4909 struct task_struct *p,
4910 bool threadgroup)
4913 #endif
4915 struct cgroup_subsys mem_cgroup_subsys = {
4916 .name = "memory",
4917 .subsys_id = mem_cgroup_subsys_id,
4918 .create = mem_cgroup_create,
4919 .pre_destroy = mem_cgroup_pre_destroy,
4920 .destroy = mem_cgroup_destroy,
4921 .populate = mem_cgroup_populate,
4922 .can_attach = mem_cgroup_can_attach,
4923 .cancel_attach = mem_cgroup_cancel_attach,
4924 .attach = mem_cgroup_move_task,
4925 .early_init = 0,
4926 .use_id = 1,
4929 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
4930 static int __init enable_swap_account(char *s)
4932 /* consider enabled if no parameter or 1 is given */
4933 if (!s || !strcmp(s, "1"))
4934 really_do_swap_account = 1;
4935 else if (!strcmp(s, "0"))
4936 really_do_swap_account = 0;
4937 return 1;
4939 __setup("swapaccount", enable_swap_account);
4941 static int __init disable_swap_account(char *s)
4943 enable_swap_account("0");
4944 return 1;
4946 __setup("noswapaccount", disable_swap_account);
4947 #endif