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>
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>
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>
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>
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;
69 static int really_do_swap_account __initdata = 0;
73 #define do_swap_account (0)
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*/
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;
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;
166 struct mem_cgroup_threshold_ary {
167 /* An array index points to threshold just below usage. */
168 int current_threshold;
169 /* Size of entries[] */
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;
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.
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
231 int last_scanned_child;
233 * Should the accounting and control be hierarchical, per subtree?
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;
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.
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 */
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 wait_queue_head_t waitq; /* a waitq for other context */
297 .lock = __SPIN_LOCK_UNLOCKED(mc.lock),
298 .waitq = __WAIT_QUEUE_HEAD_INITIALIZER(mc.waitq),
301 static bool move_anon(void)
303 return test_bit(MOVE_CHARGE_TYPE_ANON,
304 &mc.to->move_charge_at_immigrate);
307 static bool move_file(void)
309 return test_bit(MOVE_CHARGE_TYPE_FILE,
310 &mc.to->move_charge_at_immigrate);
314 * Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft
315 * limit reclaim to prevent infinite loops, if they ever occur.
317 #define MEM_CGROUP_MAX_RECLAIM_LOOPS (100)
318 #define MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS (2)
321 MEM_CGROUP_CHARGE_TYPE_CACHE = 0,
322 MEM_CGROUP_CHARGE_TYPE_MAPPED,
323 MEM_CGROUP_CHARGE_TYPE_SHMEM, /* used by page migration of shmem */
324 MEM_CGROUP_CHARGE_TYPE_FORCE, /* used by force_empty */
325 MEM_CGROUP_CHARGE_TYPE_SWAPOUT, /* for accounting swapcache */
326 MEM_CGROUP_CHARGE_TYPE_DROP, /* a page was unused swap cache */
330 /* for encoding cft->private value on file */
333 #define _OOM_TYPE (2)
334 #define MEMFILE_PRIVATE(x, val) (((x) << 16) | (val))
335 #define MEMFILE_TYPE(val) (((val) >> 16) & 0xffff)
336 #define MEMFILE_ATTR(val) ((val) & 0xffff)
337 /* Used for OOM nofiier */
338 #define OOM_CONTROL (0)
341 * Reclaim flags for mem_cgroup_hierarchical_reclaim
343 #define MEM_CGROUP_RECLAIM_NOSWAP_BIT 0x0
344 #define MEM_CGROUP_RECLAIM_NOSWAP (1 << MEM_CGROUP_RECLAIM_NOSWAP_BIT)
345 #define MEM_CGROUP_RECLAIM_SHRINK_BIT 0x1
346 #define MEM_CGROUP_RECLAIM_SHRINK (1 << MEM_CGROUP_RECLAIM_SHRINK_BIT)
347 #define MEM_CGROUP_RECLAIM_SOFT_BIT 0x2
348 #define MEM_CGROUP_RECLAIM_SOFT (1 << MEM_CGROUP_RECLAIM_SOFT_BIT)
350 static void mem_cgroup_get(struct mem_cgroup *mem);
351 static void mem_cgroup_put(struct mem_cgroup *mem);
352 static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem);
353 static void drain_all_stock_async(void);
355 static struct mem_cgroup_per_zone *
356 mem_cgroup_zoneinfo(struct mem_cgroup *mem, int nid, int zid)
358 return &mem->info.nodeinfo[nid]->zoneinfo[zid];
361 struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *mem)
366 static struct mem_cgroup_per_zone *
367 page_cgroup_zoneinfo(struct page_cgroup *pc)
369 struct mem_cgroup *mem = pc->mem_cgroup;
370 int nid = page_cgroup_nid(pc);
371 int zid = page_cgroup_zid(pc);
376 return mem_cgroup_zoneinfo(mem, nid, zid);
379 static struct mem_cgroup_tree_per_zone *
380 soft_limit_tree_node_zone(int nid, int zid)
382 return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid];
385 static struct mem_cgroup_tree_per_zone *
386 soft_limit_tree_from_page(struct page *page)
388 int nid = page_to_nid(page);
389 int zid = page_zonenum(page);
391 return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid];
395 __mem_cgroup_insert_exceeded(struct mem_cgroup *mem,
396 struct mem_cgroup_per_zone *mz,
397 struct mem_cgroup_tree_per_zone *mctz,
398 unsigned long long new_usage_in_excess)
400 struct rb_node **p = &mctz->rb_root.rb_node;
401 struct rb_node *parent = NULL;
402 struct mem_cgroup_per_zone *mz_node;
407 mz->usage_in_excess = new_usage_in_excess;
408 if (!mz->usage_in_excess)
412 mz_node = rb_entry(parent, struct mem_cgroup_per_zone,
414 if (mz->usage_in_excess < mz_node->usage_in_excess)
417 * We can't avoid mem cgroups that are over their soft
418 * limit by the same amount
420 else if (mz->usage_in_excess >= mz_node->usage_in_excess)
423 rb_link_node(&mz->tree_node, parent, p);
424 rb_insert_color(&mz->tree_node, &mctz->rb_root);
429 __mem_cgroup_remove_exceeded(struct mem_cgroup *mem,
430 struct mem_cgroup_per_zone *mz,
431 struct mem_cgroup_tree_per_zone *mctz)
435 rb_erase(&mz->tree_node, &mctz->rb_root);
440 mem_cgroup_remove_exceeded(struct mem_cgroup *mem,
441 struct mem_cgroup_per_zone *mz,
442 struct mem_cgroup_tree_per_zone *mctz)
444 spin_lock(&mctz->lock);
445 __mem_cgroup_remove_exceeded(mem, mz, mctz);
446 spin_unlock(&mctz->lock);
450 static void mem_cgroup_update_tree(struct mem_cgroup *mem, struct page *page)
452 unsigned long long excess;
453 struct mem_cgroup_per_zone *mz;
454 struct mem_cgroup_tree_per_zone *mctz;
455 int nid = page_to_nid(page);
456 int zid = page_zonenum(page);
457 mctz = soft_limit_tree_from_page(page);
460 * Necessary to update all ancestors when hierarchy is used.
461 * because their event counter is not touched.
463 for (; mem; mem = parent_mem_cgroup(mem)) {
464 mz = mem_cgroup_zoneinfo(mem, nid, zid);
465 excess = res_counter_soft_limit_excess(&mem->res);
467 * We have to update the tree if mz is on RB-tree or
468 * mem is over its softlimit.
470 if (excess || mz->on_tree) {
471 spin_lock(&mctz->lock);
472 /* if on-tree, remove it */
474 __mem_cgroup_remove_exceeded(mem, mz, mctz);
476 * Insert again. mz->usage_in_excess will be updated.
477 * If excess is 0, no tree ops.
479 __mem_cgroup_insert_exceeded(mem, mz, mctz, excess);
480 spin_unlock(&mctz->lock);
485 static void mem_cgroup_remove_from_trees(struct mem_cgroup *mem)
488 struct mem_cgroup_per_zone *mz;
489 struct mem_cgroup_tree_per_zone *mctz;
491 for_each_node_state(node, N_POSSIBLE) {
492 for (zone = 0; zone < MAX_NR_ZONES; zone++) {
493 mz = mem_cgroup_zoneinfo(mem, node, zone);
494 mctz = soft_limit_tree_node_zone(node, zone);
495 mem_cgroup_remove_exceeded(mem, mz, mctz);
500 static struct mem_cgroup_per_zone *
501 __mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
503 struct rb_node *rightmost = NULL;
504 struct mem_cgroup_per_zone *mz;
508 rightmost = rb_last(&mctz->rb_root);
510 goto done; /* Nothing to reclaim from */
512 mz = rb_entry(rightmost, struct mem_cgroup_per_zone, tree_node);
514 * Remove the node now but someone else can add it back,
515 * we will to add it back at the end of reclaim to its correct
516 * position in the tree.
518 __mem_cgroup_remove_exceeded(mz->mem, mz, mctz);
519 if (!res_counter_soft_limit_excess(&mz->mem->res) ||
520 !css_tryget(&mz->mem->css))
526 static struct mem_cgroup_per_zone *
527 mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
529 struct mem_cgroup_per_zone *mz;
531 spin_lock(&mctz->lock);
532 mz = __mem_cgroup_largest_soft_limit_node(mctz);
533 spin_unlock(&mctz->lock);
538 * Implementation Note: reading percpu statistics for memcg.
540 * Both of vmstat[] and percpu_counter has threshold and do periodic
541 * synchronization to implement "quick" read. There are trade-off between
542 * reading cost and precision of value. Then, we may have a chance to implement
543 * a periodic synchronizion of counter in memcg's counter.
545 * But this _read() function is used for user interface now. The user accounts
546 * memory usage by memory cgroup and he _always_ requires exact value because
547 * he accounts memory. Even if we provide quick-and-fuzzy read, we always
548 * have to visit all online cpus and make sum. So, for now, unnecessary
549 * synchronization is not implemented. (just implemented for cpu hotplug)
551 * If there are kernel internal actions which can make use of some not-exact
552 * value, and reading all cpu value can be performance bottleneck in some
553 * common workload, threashold and synchonization as vmstat[] should be
556 static s64 mem_cgroup_read_stat(struct mem_cgroup *mem,
557 enum mem_cgroup_stat_index idx)
563 for_each_online_cpu(cpu)
564 val += per_cpu(mem->stat->count[idx], cpu);
565 #ifdef CONFIG_HOTPLUG_CPU
566 spin_lock(&mem->pcp_counter_lock);
567 val += mem->nocpu_base.count[idx];
568 spin_unlock(&mem->pcp_counter_lock);
574 static s64 mem_cgroup_local_usage(struct mem_cgroup *mem)
578 ret = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_RSS);
579 ret += mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_CACHE);
583 static void mem_cgroup_swap_statistics(struct mem_cgroup *mem,
586 int val = (charge) ? 1 : -1;
587 this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_SWAPOUT], val);
590 static void mem_cgroup_charge_statistics(struct mem_cgroup *mem,
591 bool file, int nr_pages)
596 __this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_CACHE], nr_pages);
598 __this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_RSS], nr_pages);
600 /* pagein of a big page is an event. So, ignore page size */
602 __this_cpu_inc(mem->stat->count[MEM_CGROUP_STAT_PGPGIN_COUNT]);
604 __this_cpu_inc(mem->stat->count[MEM_CGROUP_STAT_PGPGOUT_COUNT]);
605 nr_pages = -nr_pages; /* for event */
608 __this_cpu_add(mem->stat->count[MEM_CGROUP_EVENTS], nr_pages);
613 static unsigned long mem_cgroup_get_local_zonestat(struct mem_cgroup *mem,
617 struct mem_cgroup_per_zone *mz;
620 for_each_online_node(nid)
621 for (zid = 0; zid < MAX_NR_ZONES; zid++) {
622 mz = mem_cgroup_zoneinfo(mem, nid, zid);
623 total += MEM_CGROUP_ZSTAT(mz, idx);
628 static bool __memcg_event_check(struct mem_cgroup *mem, int event_mask_shift)
632 val = this_cpu_read(mem->stat->count[MEM_CGROUP_EVENTS]);
634 return !(val & ((1 << event_mask_shift) - 1));
638 * Check events in order.
641 static void memcg_check_events(struct mem_cgroup *mem, struct page *page)
643 /* threshold event is triggered in finer grain than soft limit */
644 if (unlikely(__memcg_event_check(mem, THRESHOLDS_EVENTS_THRESH))) {
645 mem_cgroup_threshold(mem);
646 if (unlikely(__memcg_event_check(mem, SOFTLIMIT_EVENTS_THRESH)))
647 mem_cgroup_update_tree(mem, page);
651 static struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont)
653 return container_of(cgroup_subsys_state(cont,
654 mem_cgroup_subsys_id), struct mem_cgroup,
658 struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
661 * mm_update_next_owner() may clear mm->owner to NULL
662 * if it races with swapoff, page migration, etc.
663 * So this can be called with p == NULL.
668 return container_of(task_subsys_state(p, mem_cgroup_subsys_id),
669 struct mem_cgroup, css);
672 static struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm)
674 struct mem_cgroup *mem = NULL;
679 * Because we have no locks, mm->owner's may be being moved to other
680 * cgroup. We use css_tryget() here even if this looks
681 * pessimistic (rather than adding locks here).
685 mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
688 } while (!css_tryget(&mem->css));
693 /* The caller has to guarantee "mem" exists before calling this */
694 static struct mem_cgroup *mem_cgroup_start_loop(struct mem_cgroup *mem)
696 struct cgroup_subsys_state *css;
699 if (!mem) /* ROOT cgroup has the smallest ID */
700 return root_mem_cgroup; /*css_put/get against root is ignored*/
701 if (!mem->use_hierarchy) {
702 if (css_tryget(&mem->css))
708 * searching a memory cgroup which has the smallest ID under given
709 * ROOT cgroup. (ID >= 1)
711 css = css_get_next(&mem_cgroup_subsys, 1, &mem->css, &found);
712 if (css && css_tryget(css))
713 mem = container_of(css, struct mem_cgroup, css);
720 static struct mem_cgroup *mem_cgroup_get_next(struct mem_cgroup *iter,
721 struct mem_cgroup *root,
724 int nextid = css_id(&iter->css) + 1;
727 struct cgroup_subsys_state *css;
729 hierarchy_used = iter->use_hierarchy;
732 /* If no ROOT, walk all, ignore hierarchy */
733 if (!cond || (root && !hierarchy_used))
737 root = root_mem_cgroup;
743 css = css_get_next(&mem_cgroup_subsys, nextid,
745 if (css && css_tryget(css))
746 iter = container_of(css, struct mem_cgroup, css);
748 /* If css is NULL, no more cgroups will be found */
750 } while (css && !iter);
755 * for_eacn_mem_cgroup_tree() for visiting all cgroup under tree. Please
756 * be careful that "break" loop is not allowed. We have reference count.
757 * Instead of that modify "cond" to be false and "continue" to exit the loop.
759 #define for_each_mem_cgroup_tree_cond(iter, root, cond) \
760 for (iter = mem_cgroup_start_loop(root);\
762 iter = mem_cgroup_get_next(iter, root, cond))
764 #define for_each_mem_cgroup_tree(iter, root) \
765 for_each_mem_cgroup_tree_cond(iter, root, true)
767 #define for_each_mem_cgroup_all(iter) \
768 for_each_mem_cgroup_tree_cond(iter, NULL, true)
771 static inline bool mem_cgroup_is_root(struct mem_cgroup *mem)
773 return (mem == root_mem_cgroup);
777 * Following LRU functions are allowed to be used without PCG_LOCK.
778 * Operations are called by routine of global LRU independently from memcg.
779 * What we have to take care of here is validness of pc->mem_cgroup.
781 * Changes to pc->mem_cgroup happens when
784 * In typical case, "charge" is done before add-to-lru. Exception is SwapCache.
785 * It is added to LRU before charge.
786 * If PCG_USED bit is not set, page_cgroup is not added to this private LRU.
787 * When moving account, the page is not on LRU. It's isolated.
790 void mem_cgroup_del_lru_list(struct page *page, enum lru_list lru)
792 struct page_cgroup *pc;
793 struct mem_cgroup_per_zone *mz;
795 if (mem_cgroup_disabled())
797 pc = lookup_page_cgroup(page);
798 /* can happen while we handle swapcache. */
799 if (!TestClearPageCgroupAcctLRU(pc))
801 VM_BUG_ON(!pc->mem_cgroup);
803 * We don't check PCG_USED bit. It's cleared when the "page" is finally
804 * removed from global LRU.
806 mz = page_cgroup_zoneinfo(pc);
807 /* huge page split is done under lru_lock. so, we have no races. */
808 MEM_CGROUP_ZSTAT(mz, lru) -= 1 << compound_order(page);
809 if (mem_cgroup_is_root(pc->mem_cgroup))
811 VM_BUG_ON(list_empty(&pc->lru));
812 list_del_init(&pc->lru);
815 void mem_cgroup_del_lru(struct page *page)
817 mem_cgroup_del_lru_list(page, page_lru(page));
821 * Writeback is about to end against a page which has been marked for immediate
822 * reclaim. If it still appears to be reclaimable, move it to the tail of the
825 void mem_cgroup_rotate_reclaimable_page(struct page *page)
827 struct mem_cgroup_per_zone *mz;
828 struct page_cgroup *pc;
829 enum lru_list lru = page_lru(page);
831 if (mem_cgroup_disabled())
834 pc = lookup_page_cgroup(page);
835 /* unused or root page is not rotated. */
836 if (!PageCgroupUsed(pc))
838 /* Ensure pc->mem_cgroup is visible after reading PCG_USED. */
840 if (mem_cgroup_is_root(pc->mem_cgroup))
842 mz = page_cgroup_zoneinfo(pc);
843 list_move_tail(&pc->lru, &mz->lists[lru]);
846 void mem_cgroup_rotate_lru_list(struct page *page, enum lru_list lru)
848 struct mem_cgroup_per_zone *mz;
849 struct page_cgroup *pc;
851 if (mem_cgroup_disabled())
854 pc = lookup_page_cgroup(page);
855 /* unused or root page is not rotated. */
856 if (!PageCgroupUsed(pc))
858 /* Ensure pc->mem_cgroup is visible after reading PCG_USED. */
860 if (mem_cgroup_is_root(pc->mem_cgroup))
862 mz = page_cgroup_zoneinfo(pc);
863 list_move(&pc->lru, &mz->lists[lru]);
866 void mem_cgroup_add_lru_list(struct page *page, enum lru_list lru)
868 struct page_cgroup *pc;
869 struct mem_cgroup_per_zone *mz;
871 if (mem_cgroup_disabled())
873 pc = lookup_page_cgroup(page);
874 VM_BUG_ON(PageCgroupAcctLRU(pc));
875 if (!PageCgroupUsed(pc))
877 /* Ensure pc->mem_cgroup is visible after reading PCG_USED. */
879 mz = page_cgroup_zoneinfo(pc);
880 /* huge page split is done under lru_lock. so, we have no races. */
881 MEM_CGROUP_ZSTAT(mz, lru) += 1 << compound_order(page);
882 SetPageCgroupAcctLRU(pc);
883 if (mem_cgroup_is_root(pc->mem_cgroup))
885 list_add(&pc->lru, &mz->lists[lru]);
889 * At handling SwapCache, pc->mem_cgroup may be changed while it's linked to
890 * lru because the page may.be reused after it's fully uncharged (because of
891 * SwapCache behavior).To handle that, unlink page_cgroup from LRU when charge
892 * it again. This function is only used to charge SwapCache. It's done under
893 * lock_page and expected that zone->lru_lock is never held.
895 static void mem_cgroup_lru_del_before_commit_swapcache(struct page *page)
898 struct zone *zone = page_zone(page);
899 struct page_cgroup *pc = lookup_page_cgroup(page);
901 spin_lock_irqsave(&zone->lru_lock, flags);
903 * Forget old LRU when this page_cgroup is *not* used. This Used bit
904 * is guarded by lock_page() because the page is SwapCache.
906 if (!PageCgroupUsed(pc))
907 mem_cgroup_del_lru_list(page, page_lru(page));
908 spin_unlock_irqrestore(&zone->lru_lock, flags);
911 static void mem_cgroup_lru_add_after_commit_swapcache(struct page *page)
914 struct zone *zone = page_zone(page);
915 struct page_cgroup *pc = lookup_page_cgroup(page);
917 spin_lock_irqsave(&zone->lru_lock, flags);
918 /* link when the page is linked to LRU but page_cgroup isn't */
919 if (PageLRU(page) && !PageCgroupAcctLRU(pc))
920 mem_cgroup_add_lru_list(page, page_lru(page));
921 spin_unlock_irqrestore(&zone->lru_lock, flags);
925 void mem_cgroup_move_lists(struct page *page,
926 enum lru_list from, enum lru_list to)
928 if (mem_cgroup_disabled())
930 mem_cgroup_del_lru_list(page, from);
931 mem_cgroup_add_lru_list(page, to);
934 int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem)
937 struct mem_cgroup *curr = NULL;
938 struct task_struct *p;
940 p = find_lock_task_mm(task);
943 curr = try_get_mem_cgroup_from_mm(p->mm);
948 * We should check use_hierarchy of "mem" not "curr". Because checking
949 * use_hierarchy of "curr" here make this function true if hierarchy is
950 * enabled in "curr" and "curr" is a child of "mem" in *cgroup*
951 * hierarchy(even if use_hierarchy is disabled in "mem").
953 if (mem->use_hierarchy)
954 ret = css_is_ancestor(&curr->css, &mem->css);
961 static int calc_inactive_ratio(struct mem_cgroup *memcg, unsigned long *present_pages)
963 unsigned long active;
964 unsigned long inactive;
966 unsigned long inactive_ratio;
968 inactive = mem_cgroup_get_local_zonestat(memcg, LRU_INACTIVE_ANON);
969 active = mem_cgroup_get_local_zonestat(memcg, LRU_ACTIVE_ANON);
971 gb = (inactive + active) >> (30 - PAGE_SHIFT);
973 inactive_ratio = int_sqrt(10 * gb);
978 present_pages[0] = inactive;
979 present_pages[1] = active;
982 return inactive_ratio;
985 int mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg)
987 unsigned long active;
988 unsigned long inactive;
989 unsigned long present_pages[2];
990 unsigned long inactive_ratio;
992 inactive_ratio = calc_inactive_ratio(memcg, present_pages);
994 inactive = present_pages[0];
995 active = present_pages[1];
997 if (inactive * inactive_ratio < active)
1003 int mem_cgroup_inactive_file_is_low(struct mem_cgroup *memcg)
1005 unsigned long active;
1006 unsigned long inactive;
1008 inactive = mem_cgroup_get_local_zonestat(memcg, LRU_INACTIVE_FILE);
1009 active = mem_cgroup_get_local_zonestat(memcg, LRU_ACTIVE_FILE);
1011 return (active > inactive);
1014 unsigned long mem_cgroup_zone_nr_pages(struct mem_cgroup *memcg,
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 MEM_CGROUP_ZSTAT(mz, lru);
1025 struct zone_reclaim_stat *mem_cgroup_get_reclaim_stat(struct mem_cgroup *memcg,
1028 int nid = zone_to_nid(zone);
1029 int zid = zone_idx(zone);
1030 struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid);
1032 return &mz->reclaim_stat;
1035 struct zone_reclaim_stat *
1036 mem_cgroup_get_reclaim_stat_from_page(struct page *page)
1038 struct page_cgroup *pc;
1039 struct mem_cgroup_per_zone *mz;
1041 if (mem_cgroup_disabled())
1044 pc = lookup_page_cgroup(page);
1045 if (!PageCgroupUsed(pc))
1047 /* Ensure pc->mem_cgroup is visible after reading PCG_USED. */
1049 mz = page_cgroup_zoneinfo(pc);
1053 return &mz->reclaim_stat;
1056 unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
1057 struct list_head *dst,
1058 unsigned long *scanned, int order,
1059 int mode, struct zone *z,
1060 struct mem_cgroup *mem_cont,
1061 int active, int file)
1063 unsigned long nr_taken = 0;
1067 struct list_head *src;
1068 struct page_cgroup *pc, *tmp;
1069 int nid = zone_to_nid(z);
1070 int zid = zone_idx(z);
1071 struct mem_cgroup_per_zone *mz;
1072 int lru = LRU_FILE * file + active;
1076 mz = mem_cgroup_zoneinfo(mem_cont, nid, zid);
1077 src = &mz->lists[lru];
1080 list_for_each_entry_safe_reverse(pc, tmp, src, lru) {
1081 if (scan >= nr_to_scan)
1085 if (unlikely(!PageCgroupUsed(pc)))
1087 if (unlikely(!PageLRU(page)))
1091 ret = __isolate_lru_page(page, mode, file);
1094 list_move(&page->lru, dst);
1095 mem_cgroup_del_lru(page);
1096 nr_taken += hpage_nr_pages(page);
1099 /* we don't affect global LRU but rotate in our LRU */
1100 mem_cgroup_rotate_lru_list(page, page_lru(page));
1109 trace_mm_vmscan_memcg_isolate(0, nr_to_scan, scan, nr_taken,
1115 #define mem_cgroup_from_res_counter(counter, member) \
1116 container_of(counter, struct mem_cgroup, member)
1119 * mem_cgroup_margin - calculate chargeable space of a memory cgroup
1120 * @mem: the memory cgroup
1122 * Returns the maximum amount of memory @mem can be charged with, in
1125 static unsigned long long mem_cgroup_margin(struct mem_cgroup *mem)
1127 unsigned long long margin;
1129 margin = res_counter_margin(&mem->res);
1130 if (do_swap_account)
1131 margin = min(margin, res_counter_margin(&mem->memsw));
1135 static unsigned int get_swappiness(struct mem_cgroup *memcg)
1137 struct cgroup *cgrp = memcg->css.cgroup;
1138 unsigned int swappiness;
1141 if (cgrp->parent == NULL)
1142 return vm_swappiness;
1144 spin_lock(&memcg->reclaim_param_lock);
1145 swappiness = memcg->swappiness;
1146 spin_unlock(&memcg->reclaim_param_lock);
1151 static void mem_cgroup_start_move(struct mem_cgroup *mem)
1156 spin_lock(&mem->pcp_counter_lock);
1157 for_each_online_cpu(cpu)
1158 per_cpu(mem->stat->count[MEM_CGROUP_ON_MOVE], cpu) += 1;
1159 mem->nocpu_base.count[MEM_CGROUP_ON_MOVE] += 1;
1160 spin_unlock(&mem->pcp_counter_lock);
1166 static void mem_cgroup_end_move(struct mem_cgroup *mem)
1173 spin_lock(&mem->pcp_counter_lock);
1174 for_each_online_cpu(cpu)
1175 per_cpu(mem->stat->count[MEM_CGROUP_ON_MOVE], cpu) -= 1;
1176 mem->nocpu_base.count[MEM_CGROUP_ON_MOVE] -= 1;
1177 spin_unlock(&mem->pcp_counter_lock);
1181 * 2 routines for checking "mem" is under move_account() or not.
1183 * mem_cgroup_stealed() - checking a cgroup is mc.from or not. This is used
1184 * for avoiding race in accounting. If true,
1185 * pc->mem_cgroup may be overwritten.
1187 * mem_cgroup_under_move() - checking a cgroup is mc.from or mc.to or
1188 * under hierarchy of moving cgroups. This is for
1189 * waiting at hith-memory prressure caused by "move".
1192 static bool mem_cgroup_stealed(struct mem_cgroup *mem)
1194 VM_BUG_ON(!rcu_read_lock_held());
1195 return this_cpu_read(mem->stat->count[MEM_CGROUP_ON_MOVE]) > 0;
1198 static bool mem_cgroup_under_move(struct mem_cgroup *mem)
1200 struct mem_cgroup *from;
1201 struct mem_cgroup *to;
1204 * Unlike task_move routines, we access mc.to, mc.from not under
1205 * mutual exclusion by cgroup_mutex. Here, we take spinlock instead.
1207 spin_lock(&mc.lock);
1212 if (from == mem || to == mem
1213 || (mem->use_hierarchy && css_is_ancestor(&from->css, &mem->css))
1214 || (mem->use_hierarchy && css_is_ancestor(&to->css, &mem->css)))
1217 spin_unlock(&mc.lock);
1221 static bool mem_cgroup_wait_acct_move(struct mem_cgroup *mem)
1223 if (mc.moving_task && current != mc.moving_task) {
1224 if (mem_cgroup_under_move(mem)) {
1226 prepare_to_wait(&mc.waitq, &wait, TASK_INTERRUPTIBLE);
1227 /* moving charge context might have finished. */
1230 finish_wait(&mc.waitq, &wait);
1238 * mem_cgroup_print_oom_info: Called from OOM with tasklist_lock held in read mode.
1239 * @memcg: The memory cgroup that went over limit
1240 * @p: Task that is going to be killed
1242 * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is
1245 void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
1247 struct cgroup *task_cgrp;
1248 struct cgroup *mem_cgrp;
1250 * Need a buffer in BSS, can't rely on allocations. The code relies
1251 * on the assumption that OOM is serialized for memory controller.
1252 * If this assumption is broken, revisit this code.
1254 static char memcg_name[PATH_MAX];
1263 mem_cgrp = memcg->css.cgroup;
1264 task_cgrp = task_cgroup(p, mem_cgroup_subsys_id);
1266 ret = cgroup_path(task_cgrp, memcg_name, PATH_MAX);
1269 * Unfortunately, we are unable to convert to a useful name
1270 * But we'll still print out the usage information
1277 printk(KERN_INFO "Task in %s killed", memcg_name);
1280 ret = cgroup_path(mem_cgrp, memcg_name, PATH_MAX);
1288 * Continues from above, so we don't need an KERN_ level
1290 printk(KERN_CONT " as a result of limit of %s\n", memcg_name);
1293 printk(KERN_INFO "memory: usage %llukB, limit %llukB, failcnt %llu\n",
1294 res_counter_read_u64(&memcg->res, RES_USAGE) >> 10,
1295 res_counter_read_u64(&memcg->res, RES_LIMIT) >> 10,
1296 res_counter_read_u64(&memcg->res, RES_FAILCNT));
1297 printk(KERN_INFO "memory+swap: usage %llukB, limit %llukB, "
1299 res_counter_read_u64(&memcg->memsw, RES_USAGE) >> 10,
1300 res_counter_read_u64(&memcg->memsw, RES_LIMIT) >> 10,
1301 res_counter_read_u64(&memcg->memsw, RES_FAILCNT));
1305 * This function returns the number of memcg under hierarchy tree. Returns
1306 * 1(self count) if no children.
1308 static int mem_cgroup_count_children(struct mem_cgroup *mem)
1311 struct mem_cgroup *iter;
1313 for_each_mem_cgroup_tree(iter, mem)
1319 * Return the memory (and swap, if configured) limit for a memcg.
1321 u64 mem_cgroup_get_limit(struct mem_cgroup *memcg)
1326 limit = res_counter_read_u64(&memcg->res, RES_LIMIT);
1327 limit += total_swap_pages << PAGE_SHIFT;
1329 memsw = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
1331 * If memsw is finite and limits the amount of swap space available
1332 * to this memcg, return that limit.
1334 return min(limit, memsw);
1338 * Visit the first child (need not be the first child as per the ordering
1339 * of the cgroup list, since we track last_scanned_child) of @mem and use
1340 * that to reclaim free pages from.
1342 static struct mem_cgroup *
1343 mem_cgroup_select_victim(struct mem_cgroup *root_mem)
1345 struct mem_cgroup *ret = NULL;
1346 struct cgroup_subsys_state *css;
1349 if (!root_mem->use_hierarchy) {
1350 css_get(&root_mem->css);
1356 nextid = root_mem->last_scanned_child + 1;
1357 css = css_get_next(&mem_cgroup_subsys, nextid, &root_mem->css,
1359 if (css && css_tryget(css))
1360 ret = container_of(css, struct mem_cgroup, css);
1363 /* Updates scanning parameter */
1364 spin_lock(&root_mem->reclaim_param_lock);
1366 /* this means start scan from ID:1 */
1367 root_mem->last_scanned_child = 0;
1369 root_mem->last_scanned_child = found;
1370 spin_unlock(&root_mem->reclaim_param_lock);
1377 * Scan the hierarchy if needed to reclaim memory. We remember the last child
1378 * we reclaimed from, so that we don't end up penalizing one child extensively
1379 * based on its position in the children list.
1381 * root_mem is the original ancestor that we've been reclaim from.
1383 * We give up and return to the caller when we visit root_mem twice.
1384 * (other groups can be removed while we're walking....)
1386 * If shrink==true, for avoiding to free too much, this returns immedieately.
1388 static int mem_cgroup_hierarchical_reclaim(struct mem_cgroup *root_mem,
1391 unsigned long reclaim_options)
1393 struct mem_cgroup *victim;
1396 bool noswap = reclaim_options & MEM_CGROUP_RECLAIM_NOSWAP;
1397 bool shrink = reclaim_options & MEM_CGROUP_RECLAIM_SHRINK;
1398 bool check_soft = reclaim_options & MEM_CGROUP_RECLAIM_SOFT;
1399 unsigned long excess;
1401 excess = res_counter_soft_limit_excess(&root_mem->res) >> PAGE_SHIFT;
1403 /* If memsw_is_minimum==1, swap-out is of-no-use. */
1404 if (root_mem->memsw_is_minimum)
1408 victim = mem_cgroup_select_victim(root_mem);
1409 if (victim == root_mem) {
1412 drain_all_stock_async();
1415 * If we have not been able to reclaim
1416 * anything, it might because there are
1417 * no reclaimable pages under this hierarchy
1419 if (!check_soft || !total) {
1420 css_put(&victim->css);
1424 * We want to do more targetted reclaim.
1425 * excess >> 2 is not to excessive so as to
1426 * reclaim too much, nor too less that we keep
1427 * coming back to reclaim from this cgroup
1429 if (total >= (excess >> 2) ||
1430 (loop > MEM_CGROUP_MAX_RECLAIM_LOOPS)) {
1431 css_put(&victim->css);
1436 if (!mem_cgroup_local_usage(victim)) {
1437 /* this cgroup's local usage == 0 */
1438 css_put(&victim->css);
1441 /* we use swappiness of local cgroup */
1443 ret = mem_cgroup_shrink_node_zone(victim, gfp_mask,
1444 noswap, get_swappiness(victim), zone);
1446 ret = try_to_free_mem_cgroup_pages(victim, gfp_mask,
1447 noswap, get_swappiness(victim));
1448 css_put(&victim->css);
1450 * At shrinking usage, we can't check we should stop here or
1451 * reclaim more. It's depends on callers. last_scanned_child
1452 * will work enough for keeping fairness under tree.
1458 if (!res_counter_soft_limit_excess(&root_mem->res))
1460 } else if (mem_cgroup_margin(root_mem))
1467 * Check OOM-Killer is already running under our hierarchy.
1468 * If someone is running, return false.
1470 static bool mem_cgroup_oom_lock(struct mem_cgroup *mem)
1472 int x, lock_count = 0;
1473 struct mem_cgroup *iter;
1475 for_each_mem_cgroup_tree(iter, mem) {
1476 x = atomic_inc_return(&iter->oom_lock);
1477 lock_count = max(x, lock_count);
1480 if (lock_count == 1)
1485 static int mem_cgroup_oom_unlock(struct mem_cgroup *mem)
1487 struct mem_cgroup *iter;
1490 * When a new child is created while the hierarchy is under oom,
1491 * mem_cgroup_oom_lock() may not be called. We have to use
1492 * atomic_add_unless() here.
1494 for_each_mem_cgroup_tree(iter, mem)
1495 atomic_add_unless(&iter->oom_lock, -1, 0);
1500 static DEFINE_MUTEX(memcg_oom_mutex);
1501 static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq);
1503 struct oom_wait_info {
1504 struct mem_cgroup *mem;
1508 static int memcg_oom_wake_function(wait_queue_t *wait,
1509 unsigned mode, int sync, void *arg)
1511 struct mem_cgroup *wake_mem = (struct mem_cgroup *)arg;
1512 struct oom_wait_info *oom_wait_info;
1514 oom_wait_info = container_of(wait, struct oom_wait_info, wait);
1516 if (oom_wait_info->mem == wake_mem)
1518 /* if no hierarchy, no match */
1519 if (!oom_wait_info->mem->use_hierarchy || !wake_mem->use_hierarchy)
1522 * Both of oom_wait_info->mem and wake_mem are stable under us.
1523 * Then we can use css_is_ancestor without taking care of RCU.
1525 if (!css_is_ancestor(&oom_wait_info->mem->css, &wake_mem->css) &&
1526 !css_is_ancestor(&wake_mem->css, &oom_wait_info->mem->css))
1530 return autoremove_wake_function(wait, mode, sync, arg);
1533 static void memcg_wakeup_oom(struct mem_cgroup *mem)
1535 /* for filtering, pass "mem" as argument. */
1536 __wake_up(&memcg_oom_waitq, TASK_NORMAL, 0, mem);
1539 static void memcg_oom_recover(struct mem_cgroup *mem)
1541 if (mem && atomic_read(&mem->oom_lock))
1542 memcg_wakeup_oom(mem);
1546 * try to call OOM killer. returns false if we should exit memory-reclaim loop.
1548 bool mem_cgroup_handle_oom(struct mem_cgroup *mem, gfp_t mask)
1550 struct oom_wait_info owait;
1551 bool locked, need_to_kill;
1554 owait.wait.flags = 0;
1555 owait.wait.func = memcg_oom_wake_function;
1556 owait.wait.private = current;
1557 INIT_LIST_HEAD(&owait.wait.task_list);
1558 need_to_kill = true;
1559 /* At first, try to OOM lock hierarchy under mem.*/
1560 mutex_lock(&memcg_oom_mutex);
1561 locked = mem_cgroup_oom_lock(mem);
1563 * Even if signal_pending(), we can't quit charge() loop without
1564 * accounting. So, UNINTERRUPTIBLE is appropriate. But SIGKILL
1565 * under OOM is always welcomed, use TASK_KILLABLE here.
1567 prepare_to_wait(&memcg_oom_waitq, &owait.wait, TASK_KILLABLE);
1568 if (!locked || mem->oom_kill_disable)
1569 need_to_kill = false;
1571 mem_cgroup_oom_notify(mem);
1572 mutex_unlock(&memcg_oom_mutex);
1575 finish_wait(&memcg_oom_waitq, &owait.wait);
1576 mem_cgroup_out_of_memory(mem, mask);
1579 finish_wait(&memcg_oom_waitq, &owait.wait);
1581 mutex_lock(&memcg_oom_mutex);
1582 mem_cgroup_oom_unlock(mem);
1583 memcg_wakeup_oom(mem);
1584 mutex_unlock(&memcg_oom_mutex);
1586 if (test_thread_flag(TIF_MEMDIE) || fatal_signal_pending(current))
1588 /* Give chance to dying process */
1589 schedule_timeout(1);
1594 * Currently used to update mapped file statistics, but the routine can be
1595 * generalized to update other statistics as well.
1597 * Notes: Race condition
1599 * We usually use page_cgroup_lock() for accessing page_cgroup member but
1600 * it tends to be costly. But considering some conditions, we doesn't need
1601 * to do so _always_.
1603 * Considering "charge", lock_page_cgroup() is not required because all
1604 * file-stat operations happen after a page is attached to radix-tree. There
1605 * are no race with "charge".
1607 * Considering "uncharge", we know that memcg doesn't clear pc->mem_cgroup
1608 * at "uncharge" intentionally. So, we always see valid pc->mem_cgroup even
1609 * if there are race with "uncharge". Statistics itself is properly handled
1612 * Considering "move", this is an only case we see a race. To make the race
1613 * small, we check MEM_CGROUP_ON_MOVE percpu value and detect there are
1614 * possibility of race condition. If there is, we take a lock.
1617 void mem_cgroup_update_page_stat(struct page *page,
1618 enum mem_cgroup_page_stat_item idx, int val)
1620 struct mem_cgroup *mem;
1621 struct page_cgroup *pc = lookup_page_cgroup(page);
1622 bool need_unlock = false;
1623 unsigned long uninitialized_var(flags);
1629 mem = pc->mem_cgroup;
1630 if (unlikely(!mem || !PageCgroupUsed(pc)))
1632 /* pc->mem_cgroup is unstable ? */
1633 if (unlikely(mem_cgroup_stealed(mem)) || PageTransHuge(page)) {
1634 /* take a lock against to access pc->mem_cgroup */
1635 move_lock_page_cgroup(pc, &flags);
1637 mem = pc->mem_cgroup;
1638 if (!mem || !PageCgroupUsed(pc))
1643 case MEMCG_NR_FILE_MAPPED:
1645 SetPageCgroupFileMapped(pc);
1646 else if (!page_mapped(page))
1647 ClearPageCgroupFileMapped(pc);
1648 idx = MEM_CGROUP_STAT_FILE_MAPPED;
1654 this_cpu_add(mem->stat->count[idx], val);
1657 if (unlikely(need_unlock))
1658 move_unlock_page_cgroup(pc, &flags);
1662 EXPORT_SYMBOL(mem_cgroup_update_page_stat);
1665 * size of first charge trial. "32" comes from vmscan.c's magic value.
1666 * TODO: maybe necessary to use big numbers in big irons.
1668 #define CHARGE_SIZE (32 * PAGE_SIZE)
1669 struct memcg_stock_pcp {
1670 struct mem_cgroup *cached; /* this never be root cgroup */
1672 struct work_struct work;
1674 static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock);
1675 static atomic_t memcg_drain_count;
1678 * Try to consume stocked charge on this cpu. If success, PAGE_SIZE is consumed
1679 * from local stock and true is returned. If the stock is 0 or charges from a
1680 * cgroup which is not current target, returns false. This stock will be
1683 static bool consume_stock(struct mem_cgroup *mem)
1685 struct memcg_stock_pcp *stock;
1688 stock = &get_cpu_var(memcg_stock);
1689 if (mem == stock->cached && stock->charge)
1690 stock->charge -= PAGE_SIZE;
1691 else /* need to call res_counter_charge */
1693 put_cpu_var(memcg_stock);
1698 * Returns stocks cached in percpu to res_counter and reset cached information.
1700 static void drain_stock(struct memcg_stock_pcp *stock)
1702 struct mem_cgroup *old = stock->cached;
1704 if (stock->charge) {
1705 res_counter_uncharge(&old->res, stock->charge);
1706 if (do_swap_account)
1707 res_counter_uncharge(&old->memsw, stock->charge);
1709 stock->cached = NULL;
1714 * This must be called under preempt disabled or must be called by
1715 * a thread which is pinned to local cpu.
1717 static void drain_local_stock(struct work_struct *dummy)
1719 struct memcg_stock_pcp *stock = &__get_cpu_var(memcg_stock);
1724 * Cache charges(val) which is from res_counter, to local per_cpu area.
1725 * This will be consumed by consume_stock() function, later.
1727 static void refill_stock(struct mem_cgroup *mem, int val)
1729 struct memcg_stock_pcp *stock = &get_cpu_var(memcg_stock);
1731 if (stock->cached != mem) { /* reset if necessary */
1733 stock->cached = mem;
1735 stock->charge += val;
1736 put_cpu_var(memcg_stock);
1740 * Tries to drain stocked charges in other cpus. This function is asynchronous
1741 * and just put a work per cpu for draining localy on each cpu. Caller can
1742 * expects some charges will be back to res_counter later but cannot wait for
1745 static void drain_all_stock_async(void)
1748 /* This function is for scheduling "drain" in asynchronous way.
1749 * The result of "drain" is not directly handled by callers. Then,
1750 * if someone is calling drain, we don't have to call drain more.
1751 * Anyway, WORK_STRUCT_PENDING check in queue_work_on() will catch if
1752 * there is a race. We just do loose check here.
1754 if (atomic_read(&memcg_drain_count))
1756 /* Notify other cpus that system-wide "drain" is running */
1757 atomic_inc(&memcg_drain_count);
1759 for_each_online_cpu(cpu) {
1760 struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
1761 schedule_work_on(cpu, &stock->work);
1764 atomic_dec(&memcg_drain_count);
1765 /* We don't wait for flush_work */
1768 /* This is a synchronous drain interface. */
1769 static void drain_all_stock_sync(void)
1771 /* called when force_empty is called */
1772 atomic_inc(&memcg_drain_count);
1773 schedule_on_each_cpu(drain_local_stock);
1774 atomic_dec(&memcg_drain_count);
1778 * This function drains percpu counter value from DEAD cpu and
1779 * move it to local cpu. Note that this function can be preempted.
1781 static void mem_cgroup_drain_pcp_counter(struct mem_cgroup *mem, int cpu)
1785 spin_lock(&mem->pcp_counter_lock);
1786 for (i = 0; i < MEM_CGROUP_STAT_DATA; i++) {
1787 s64 x = per_cpu(mem->stat->count[i], cpu);
1789 per_cpu(mem->stat->count[i], cpu) = 0;
1790 mem->nocpu_base.count[i] += x;
1792 /* need to clear ON_MOVE value, works as a kind of lock. */
1793 per_cpu(mem->stat->count[MEM_CGROUP_ON_MOVE], cpu) = 0;
1794 spin_unlock(&mem->pcp_counter_lock);
1797 static void synchronize_mem_cgroup_on_move(struct mem_cgroup *mem, int cpu)
1799 int idx = MEM_CGROUP_ON_MOVE;
1801 spin_lock(&mem->pcp_counter_lock);
1802 per_cpu(mem->stat->count[idx], cpu) = mem->nocpu_base.count[idx];
1803 spin_unlock(&mem->pcp_counter_lock);
1806 static int __cpuinit memcg_cpu_hotplug_callback(struct notifier_block *nb,
1807 unsigned long action,
1810 int cpu = (unsigned long)hcpu;
1811 struct memcg_stock_pcp *stock;
1812 struct mem_cgroup *iter;
1814 if ((action == CPU_ONLINE)) {
1815 for_each_mem_cgroup_all(iter)
1816 synchronize_mem_cgroup_on_move(iter, cpu);
1820 if ((action != CPU_DEAD) || action != CPU_DEAD_FROZEN)
1823 for_each_mem_cgroup_all(iter)
1824 mem_cgroup_drain_pcp_counter(iter, cpu);
1826 stock = &per_cpu(memcg_stock, cpu);
1832 /* See __mem_cgroup_try_charge() for details */
1834 CHARGE_OK, /* success */
1835 CHARGE_RETRY, /* need to retry but retry is not bad */
1836 CHARGE_NOMEM, /* we can't do more. return -ENOMEM */
1837 CHARGE_WOULDBLOCK, /* GFP_WAIT wasn't set and no enough res. */
1838 CHARGE_OOM_DIE, /* the current is killed because of OOM */
1841 static int __mem_cgroup_do_charge(struct mem_cgroup *mem, gfp_t gfp_mask,
1842 int csize, bool oom_check)
1844 struct mem_cgroup *mem_over_limit;
1845 struct res_counter *fail_res;
1846 unsigned long flags = 0;
1849 ret = res_counter_charge(&mem->res, csize, &fail_res);
1852 if (!do_swap_account)
1854 ret = res_counter_charge(&mem->memsw, csize, &fail_res);
1858 res_counter_uncharge(&mem->res, csize);
1859 mem_over_limit = mem_cgroup_from_res_counter(fail_res, memsw);
1860 flags |= MEM_CGROUP_RECLAIM_NOSWAP;
1862 mem_over_limit = mem_cgroup_from_res_counter(fail_res, res);
1864 * csize can be either a huge page (HPAGE_SIZE), a batch of
1865 * regular pages (CHARGE_SIZE), or a single regular page
1868 * Never reclaim on behalf of optional batching, retry with a
1869 * single page instead.
1871 if (csize == CHARGE_SIZE)
1872 return CHARGE_RETRY;
1874 if (!(gfp_mask & __GFP_WAIT))
1875 return CHARGE_WOULDBLOCK;
1877 ret = mem_cgroup_hierarchical_reclaim(mem_over_limit, NULL,
1879 if (mem_cgroup_margin(mem_over_limit) >= csize)
1880 return CHARGE_RETRY;
1882 * Even though the limit is exceeded at this point, reclaim
1883 * may have been able to free some pages. Retry the charge
1884 * before killing the task.
1886 * Only for regular pages, though: huge pages are rather
1887 * unlikely to succeed so close to the limit, and we fall back
1888 * to regular pages anyway in case of failure.
1890 if (csize == PAGE_SIZE && ret)
1891 return CHARGE_RETRY;
1894 * At task move, charge accounts can be doubly counted. So, it's
1895 * better to wait until the end of task_move if something is going on.
1897 if (mem_cgroup_wait_acct_move(mem_over_limit))
1898 return CHARGE_RETRY;
1900 /* If we don't need to call oom-killer at el, return immediately */
1902 return CHARGE_NOMEM;
1904 if (!mem_cgroup_handle_oom(mem_over_limit, gfp_mask))
1905 return CHARGE_OOM_DIE;
1907 return CHARGE_RETRY;
1911 * Unlike exported interface, "oom" parameter is added. if oom==true,
1912 * oom-killer can be invoked.
1914 static int __mem_cgroup_try_charge(struct mm_struct *mm,
1916 struct mem_cgroup **memcg, bool oom,
1919 int nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES;
1920 struct mem_cgroup *mem = NULL;
1922 int csize = max(CHARGE_SIZE, (unsigned long) page_size);
1925 * Unlike gloval-vm's OOM-kill, we're not in memory shortage
1926 * in system level. So, allow to go ahead dying process in addition to
1929 if (unlikely(test_thread_flag(TIF_MEMDIE)
1930 || fatal_signal_pending(current)))
1934 * We always charge the cgroup the mm_struct belongs to.
1935 * The mm_struct's mem_cgroup changes on task migration if the
1936 * thread group leader migrates. It's possible that mm is not
1937 * set, if so charge the init_mm (happens for pagecache usage).
1942 if (*memcg) { /* css should be a valid one */
1944 VM_BUG_ON(css_is_removed(&mem->css));
1945 if (mem_cgroup_is_root(mem))
1947 if (page_size == PAGE_SIZE && consume_stock(mem))
1951 struct task_struct *p;
1954 p = rcu_dereference(mm->owner);
1956 * Because we don't have task_lock(), "p" can exit.
1957 * In that case, "mem" can point to root or p can be NULL with
1958 * race with swapoff. Then, we have small risk of mis-accouning.
1959 * But such kind of mis-account by race always happens because
1960 * we don't have cgroup_mutex(). It's overkill and we allo that
1962 * (*) swapoff at el will charge against mm-struct not against
1963 * task-struct. So, mm->owner can be NULL.
1965 mem = mem_cgroup_from_task(p);
1966 if (!mem || mem_cgroup_is_root(mem)) {
1970 if (page_size == PAGE_SIZE && consume_stock(mem)) {
1972 * It seems dagerous to access memcg without css_get().
1973 * But considering how consume_stok works, it's not
1974 * necessary. If consume_stock success, some charges
1975 * from this memcg are cached on this cpu. So, we
1976 * don't need to call css_get()/css_tryget() before
1977 * calling consume_stock().
1982 /* after here, we may be blocked. we need to get refcnt */
1983 if (!css_tryget(&mem->css)) {
1993 /* If killed, bypass charge */
1994 if (fatal_signal_pending(current)) {
2000 if (oom && !nr_oom_retries) {
2002 nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES;
2005 ret = __mem_cgroup_do_charge(mem, gfp_mask, csize, oom_check);
2010 case CHARGE_RETRY: /* not in OOM situation but retry */
2015 case CHARGE_WOULDBLOCK: /* !__GFP_WAIT */
2018 case CHARGE_NOMEM: /* OOM routine works */
2023 /* If oom, we never return -ENOMEM */
2026 case CHARGE_OOM_DIE: /* Killed by OOM Killer */
2030 } while (ret != CHARGE_OK);
2032 if (csize > page_size)
2033 refill_stock(mem, csize - page_size);
2047 * Somemtimes we have to undo a charge we got by try_charge().
2048 * This function is for that and do uncharge, put css's refcnt.
2049 * gotten by try_charge().
2051 static void __mem_cgroup_cancel_charge(struct mem_cgroup *mem,
2052 unsigned long count)
2054 if (!mem_cgroup_is_root(mem)) {
2055 res_counter_uncharge(&mem->res, PAGE_SIZE * count);
2056 if (do_swap_account)
2057 res_counter_uncharge(&mem->memsw, PAGE_SIZE * count);
2061 static void mem_cgroup_cancel_charge(struct mem_cgroup *mem,
2064 __mem_cgroup_cancel_charge(mem, page_size >> PAGE_SHIFT);
2068 * A helper function to get mem_cgroup from ID. must be called under
2069 * rcu_read_lock(). The caller must check css_is_removed() or some if
2070 * it's concern. (dropping refcnt from swap can be called against removed
2073 static struct mem_cgroup *mem_cgroup_lookup(unsigned short id)
2075 struct cgroup_subsys_state *css;
2077 /* ID 0 is unused ID */
2080 css = css_lookup(&mem_cgroup_subsys, id);
2083 return container_of(css, struct mem_cgroup, css);
2086 struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page)
2088 struct mem_cgroup *mem = NULL;
2089 struct page_cgroup *pc;
2093 VM_BUG_ON(!PageLocked(page));
2095 pc = lookup_page_cgroup(page);
2096 lock_page_cgroup(pc);
2097 if (PageCgroupUsed(pc)) {
2098 mem = pc->mem_cgroup;
2099 if (mem && !css_tryget(&mem->css))
2101 } else if (PageSwapCache(page)) {
2102 ent.val = page_private(page);
2103 id = lookup_swap_cgroup(ent);
2105 mem = mem_cgroup_lookup(id);
2106 if (mem && !css_tryget(&mem->css))
2110 unlock_page_cgroup(pc);
2114 static void __mem_cgroup_commit_charge(struct mem_cgroup *mem,
2115 struct page_cgroup *pc,
2116 enum charge_type ctype,
2119 int nr_pages = page_size >> PAGE_SHIFT;
2121 lock_page_cgroup(pc);
2122 if (unlikely(PageCgroupUsed(pc))) {
2123 unlock_page_cgroup(pc);
2124 mem_cgroup_cancel_charge(mem, page_size);
2128 * we don't need page_cgroup_lock about tail pages, becase they are not
2129 * accessed by any other context at this point.
2131 pc->mem_cgroup = mem;
2133 * We access a page_cgroup asynchronously without lock_page_cgroup().
2134 * Especially when a page_cgroup is taken from a page, pc->mem_cgroup
2135 * is accessed after testing USED bit. To make pc->mem_cgroup visible
2136 * before USED bit, we need memory barrier here.
2137 * See mem_cgroup_add_lru_list(), etc.
2141 case MEM_CGROUP_CHARGE_TYPE_CACHE:
2142 case MEM_CGROUP_CHARGE_TYPE_SHMEM:
2143 SetPageCgroupCache(pc);
2144 SetPageCgroupUsed(pc);
2146 case MEM_CGROUP_CHARGE_TYPE_MAPPED:
2147 ClearPageCgroupCache(pc);
2148 SetPageCgroupUsed(pc);
2154 mem_cgroup_charge_statistics(mem, PageCgroupCache(pc), nr_pages);
2155 unlock_page_cgroup(pc);
2157 * "charge_statistics" updated event counter. Then, check it.
2158 * Insert ancestor (and ancestor's ancestors), to softlimit RB-tree.
2159 * if they exceeds softlimit.
2161 memcg_check_events(mem, pc->page);
2164 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
2166 #define PCGF_NOCOPY_AT_SPLIT ((1 << PCG_LOCK) | (1 << PCG_MOVE_LOCK) |\
2167 (1 << PCG_ACCT_LRU) | (1 << PCG_MIGRATION))
2169 * Because tail pages are not marked as "used", set it. We're under
2170 * zone->lru_lock, 'splitting on pmd' and compund_lock.
2172 void mem_cgroup_split_huge_fixup(struct page *head, struct page *tail)
2174 struct page_cgroup *head_pc = lookup_page_cgroup(head);
2175 struct page_cgroup *tail_pc = lookup_page_cgroup(tail);
2176 unsigned long flags;
2178 if (mem_cgroup_disabled())
2181 * We have no races with charge/uncharge but will have races with
2182 * page state accounting.
2184 move_lock_page_cgroup(head_pc, &flags);
2186 tail_pc->mem_cgroup = head_pc->mem_cgroup;
2187 smp_wmb(); /* see __commit_charge() */
2188 if (PageCgroupAcctLRU(head_pc)) {
2190 struct mem_cgroup_per_zone *mz;
2193 * LRU flags cannot be copied because we need to add tail
2194 *.page to LRU by generic call and our hook will be called.
2195 * We hold lru_lock, then, reduce counter directly.
2197 lru = page_lru(head);
2198 mz = page_cgroup_zoneinfo(head_pc);
2199 MEM_CGROUP_ZSTAT(mz, lru) -= 1;
2201 tail_pc->flags = head_pc->flags & ~PCGF_NOCOPY_AT_SPLIT;
2202 move_unlock_page_cgroup(head_pc, &flags);
2207 * __mem_cgroup_move_account - move account of the page
2208 * @pc: page_cgroup of the page.
2209 * @from: mem_cgroup which the page is moved from.
2210 * @to: mem_cgroup which the page is moved to. @from != @to.
2211 * @uncharge: whether we should call uncharge and css_put against @from.
2213 * The caller must confirm following.
2214 * - page is not on LRU (isolate_page() is useful.)
2215 * - the pc is locked, used, and ->mem_cgroup points to @from.
2217 * This function doesn't do "charge" nor css_get to new cgroup. It should be
2218 * done by a caller(__mem_cgroup_try_charge would be usefull). If @uncharge is
2219 * true, this function does "uncharge" from old cgroup, but it doesn't if
2220 * @uncharge is false, so a caller should do "uncharge".
2223 static void __mem_cgroup_move_account(struct page_cgroup *pc,
2224 struct mem_cgroup *from, struct mem_cgroup *to, bool uncharge,
2227 int nr_pages = charge_size >> PAGE_SHIFT;
2229 VM_BUG_ON(from == to);
2230 VM_BUG_ON(PageLRU(pc->page));
2231 VM_BUG_ON(!page_is_cgroup_locked(pc));
2232 VM_BUG_ON(!PageCgroupUsed(pc));
2233 VM_BUG_ON(pc->mem_cgroup != from);
2235 if (PageCgroupFileMapped(pc)) {
2236 /* Update mapped_file data for mem_cgroup */
2238 __this_cpu_dec(from->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]);
2239 __this_cpu_inc(to->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]);
2242 mem_cgroup_charge_statistics(from, PageCgroupCache(pc), -nr_pages);
2244 /* This is not "cancel", but cancel_charge does all we need. */
2245 mem_cgroup_cancel_charge(from, charge_size);
2247 /* caller should have done css_get */
2248 pc->mem_cgroup = to;
2249 mem_cgroup_charge_statistics(to, PageCgroupCache(pc), nr_pages);
2251 * We charges against "to" which may not have any tasks. Then, "to"
2252 * can be under rmdir(). But in current implementation, caller of
2253 * this function is just force_empty() and move charge, so it's
2254 * garanteed that "to" is never removed. So, we don't check rmdir
2260 * check whether the @pc is valid for moving account and call
2261 * __mem_cgroup_move_account()
2263 static int mem_cgroup_move_account(struct page_cgroup *pc,
2264 struct mem_cgroup *from, struct mem_cgroup *to,
2265 bool uncharge, int charge_size)
2268 unsigned long flags;
2270 * The page is isolated from LRU. So, collapse function
2271 * will not handle this page. But page splitting can happen.
2272 * Do this check under compound_page_lock(). The caller should
2275 if ((charge_size > PAGE_SIZE) && !PageTransHuge(pc->page))
2278 lock_page_cgroup(pc);
2279 if (PageCgroupUsed(pc) && pc->mem_cgroup == from) {
2280 move_lock_page_cgroup(pc, &flags);
2281 __mem_cgroup_move_account(pc, from, to, uncharge, charge_size);
2282 move_unlock_page_cgroup(pc, &flags);
2285 unlock_page_cgroup(pc);
2289 memcg_check_events(to, pc->page);
2290 memcg_check_events(from, pc->page);
2295 * move charges to its parent.
2298 static int mem_cgroup_move_parent(struct page_cgroup *pc,
2299 struct mem_cgroup *child,
2302 struct page *page = pc->page;
2303 struct cgroup *cg = child->css.cgroup;
2304 struct cgroup *pcg = cg->parent;
2305 struct mem_cgroup *parent;
2306 int page_size = PAGE_SIZE;
2307 unsigned long flags;
2315 if (!get_page_unless_zero(page))
2317 if (isolate_lru_page(page))
2320 if (PageTransHuge(page))
2321 page_size = HPAGE_SIZE;
2323 parent = mem_cgroup_from_cont(pcg);
2324 ret = __mem_cgroup_try_charge(NULL, gfp_mask,
2325 &parent, false, page_size);
2329 if (page_size > PAGE_SIZE)
2330 flags = compound_lock_irqsave(page);
2332 ret = mem_cgroup_move_account(pc, child, parent, true, page_size);
2334 mem_cgroup_cancel_charge(parent, page_size);
2336 if (page_size > PAGE_SIZE)
2337 compound_unlock_irqrestore(page, flags);
2339 putback_lru_page(page);
2347 * Charge the memory controller for page usage.
2349 * 0 if the charge was successful
2350 * < 0 if the cgroup is over its limit
2352 static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm,
2353 gfp_t gfp_mask, enum charge_type ctype)
2355 struct mem_cgroup *mem = NULL;
2356 int page_size = PAGE_SIZE;
2357 struct page_cgroup *pc;
2361 if (PageTransHuge(page)) {
2362 page_size <<= compound_order(page);
2363 VM_BUG_ON(!PageTransHuge(page));
2365 * Never OOM-kill a process for a huge page. The
2366 * fault handler will fall back to regular pages.
2371 pc = lookup_page_cgroup(page);
2372 /* can happen at boot */
2377 ret = __mem_cgroup_try_charge(mm, gfp_mask, &mem, oom, page_size);
2381 __mem_cgroup_commit_charge(mem, pc, ctype, page_size);
2385 int mem_cgroup_newpage_charge(struct page *page,
2386 struct mm_struct *mm, gfp_t gfp_mask)
2388 if (mem_cgroup_disabled())
2391 * If already mapped, we don't have to account.
2392 * If page cache, page->mapping has address_space.
2393 * But page->mapping may have out-of-use anon_vma pointer,
2394 * detecit it by PageAnon() check. newly-mapped-anon's page->mapping
2397 if (page_mapped(page) || (page->mapping && !PageAnon(page)))
2401 return mem_cgroup_charge_common(page, mm, gfp_mask,
2402 MEM_CGROUP_CHARGE_TYPE_MAPPED);
2406 __mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr,
2407 enum charge_type ctype);
2409 int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
2414 if (mem_cgroup_disabled())
2416 if (PageCompound(page))
2419 * Corner case handling. This is called from add_to_page_cache()
2420 * in usual. But some FS (shmem) precharges this page before calling it
2421 * and call add_to_page_cache() with GFP_NOWAIT.
2423 * For GFP_NOWAIT case, the page may be pre-charged before calling
2424 * add_to_page_cache(). (See shmem.c) check it here and avoid to call
2425 * charge twice. (It works but has to pay a bit larger cost.)
2426 * And when the page is SwapCache, it should take swap information
2427 * into account. This is under lock_page() now.
2429 if (!(gfp_mask & __GFP_WAIT)) {
2430 struct page_cgroup *pc;
2432 pc = lookup_page_cgroup(page);
2435 lock_page_cgroup(pc);
2436 if (PageCgroupUsed(pc)) {
2437 unlock_page_cgroup(pc);
2440 unlock_page_cgroup(pc);
2446 if (page_is_file_cache(page))
2447 return mem_cgroup_charge_common(page, mm, gfp_mask,
2448 MEM_CGROUP_CHARGE_TYPE_CACHE);
2451 if (PageSwapCache(page)) {
2452 struct mem_cgroup *mem;
2454 ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &mem);
2456 __mem_cgroup_commit_charge_swapin(page, mem,
2457 MEM_CGROUP_CHARGE_TYPE_SHMEM);
2459 ret = mem_cgroup_charge_common(page, mm, gfp_mask,
2460 MEM_CGROUP_CHARGE_TYPE_SHMEM);
2466 * While swap-in, try_charge -> commit or cancel, the page is locked.
2467 * And when try_charge() successfully returns, one refcnt to memcg without
2468 * struct page_cgroup is acquired. This refcnt will be consumed by
2469 * "commit()" or removed by "cancel()"
2471 int mem_cgroup_try_charge_swapin(struct mm_struct *mm,
2473 gfp_t mask, struct mem_cgroup **ptr)
2475 struct mem_cgroup *mem;
2480 if (mem_cgroup_disabled())
2483 if (!do_swap_account)
2486 * A racing thread's fault, or swapoff, may have already updated
2487 * the pte, and even removed page from swap cache: in those cases
2488 * do_swap_page()'s pte_same() test will fail; but there's also a
2489 * KSM case which does need to charge the page.
2491 if (!PageSwapCache(page))
2493 mem = try_get_mem_cgroup_from_page(page);
2497 ret = __mem_cgroup_try_charge(NULL, mask, ptr, true, PAGE_SIZE);
2503 return __mem_cgroup_try_charge(mm, mask, ptr, true, PAGE_SIZE);
2507 __mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr,
2508 enum charge_type ctype)
2510 struct page_cgroup *pc;
2512 if (mem_cgroup_disabled())
2516 cgroup_exclude_rmdir(&ptr->css);
2517 pc = lookup_page_cgroup(page);
2518 mem_cgroup_lru_del_before_commit_swapcache(page);
2519 __mem_cgroup_commit_charge(ptr, pc, ctype, PAGE_SIZE);
2520 mem_cgroup_lru_add_after_commit_swapcache(page);
2522 * Now swap is on-memory. This means this page may be
2523 * counted both as mem and swap....double count.
2524 * Fix it by uncharging from memsw. Basically, this SwapCache is stable
2525 * under lock_page(). But in do_swap_page()::memory.c, reuse_swap_page()
2526 * may call delete_from_swap_cache() before reach here.
2528 if (do_swap_account && PageSwapCache(page)) {
2529 swp_entry_t ent = {.val = page_private(page)};
2531 struct mem_cgroup *memcg;
2533 id = swap_cgroup_record(ent, 0);
2535 memcg = mem_cgroup_lookup(id);
2538 * This recorded memcg can be obsolete one. So, avoid
2539 * calling css_tryget
2541 if (!mem_cgroup_is_root(memcg))
2542 res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
2543 mem_cgroup_swap_statistics(memcg, false);
2544 mem_cgroup_put(memcg);
2549 * At swapin, we may charge account against cgroup which has no tasks.
2550 * So, rmdir()->pre_destroy() can be called while we do this charge.
2551 * In that case, we need to call pre_destroy() again. check it here.
2553 cgroup_release_and_wakeup_rmdir(&ptr->css);
2556 void mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr)
2558 __mem_cgroup_commit_charge_swapin(page, ptr,
2559 MEM_CGROUP_CHARGE_TYPE_MAPPED);
2562 void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *mem)
2564 if (mem_cgroup_disabled())
2568 mem_cgroup_cancel_charge(mem, PAGE_SIZE);
2572 __do_uncharge(struct mem_cgroup *mem, const enum charge_type ctype,
2575 struct memcg_batch_info *batch = NULL;
2576 bool uncharge_memsw = true;
2577 /* If swapout, usage of swap doesn't decrease */
2578 if (!do_swap_account || ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT)
2579 uncharge_memsw = false;
2581 batch = ¤t->memcg_batch;
2583 * In usual, we do css_get() when we remember memcg pointer.
2584 * But in this case, we keep res->usage until end of a series of
2585 * uncharges. Then, it's ok to ignore memcg's refcnt.
2590 * do_batch > 0 when unmapping pages or inode invalidate/truncate.
2591 * In those cases, all pages freed continously can be expected to be in
2592 * the same cgroup and we have chance to coalesce uncharges.
2593 * But we do uncharge one by one if this is killed by OOM(TIF_MEMDIE)
2594 * because we want to do uncharge as soon as possible.
2597 if (!batch->do_batch || test_thread_flag(TIF_MEMDIE))
2598 goto direct_uncharge;
2600 if (page_size != PAGE_SIZE)
2601 goto direct_uncharge;
2604 * In typical case, batch->memcg == mem. This means we can
2605 * merge a series of uncharges to an uncharge of res_counter.
2606 * If not, we uncharge res_counter ony by one.
2608 if (batch->memcg != mem)
2609 goto direct_uncharge;
2610 /* remember freed charge and uncharge it later */
2611 batch->bytes += PAGE_SIZE;
2613 batch->memsw_bytes += PAGE_SIZE;
2616 res_counter_uncharge(&mem->res, page_size);
2618 res_counter_uncharge(&mem->memsw, page_size);
2619 if (unlikely(batch->memcg != mem))
2620 memcg_oom_recover(mem);
2625 * uncharge if !page_mapped(page)
2627 static struct mem_cgroup *
2628 __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
2631 struct page_cgroup *pc;
2632 struct mem_cgroup *mem = NULL;
2633 int page_size = PAGE_SIZE;
2635 if (mem_cgroup_disabled())
2638 if (PageSwapCache(page))
2641 if (PageTransHuge(page)) {
2642 page_size <<= compound_order(page);
2643 VM_BUG_ON(!PageTransHuge(page));
2646 count = page_size >> PAGE_SHIFT;
2648 * Check if our page_cgroup is valid
2650 pc = lookup_page_cgroup(page);
2651 if (unlikely(!pc || !PageCgroupUsed(pc)))
2654 lock_page_cgroup(pc);
2656 mem = pc->mem_cgroup;
2658 if (!PageCgroupUsed(pc))
2662 case MEM_CGROUP_CHARGE_TYPE_MAPPED:
2663 case MEM_CGROUP_CHARGE_TYPE_DROP:
2664 /* See mem_cgroup_prepare_migration() */
2665 if (page_mapped(page) || PageCgroupMigration(pc))
2668 case MEM_CGROUP_CHARGE_TYPE_SWAPOUT:
2669 if (!PageAnon(page)) { /* Shared memory */
2670 if (page->mapping && !page_is_file_cache(page))
2672 } else if (page_mapped(page)) /* Anon */
2679 mem_cgroup_charge_statistics(mem, PageCgroupCache(pc), -count);
2681 ClearPageCgroupUsed(pc);
2683 * pc->mem_cgroup is not cleared here. It will be accessed when it's
2684 * freed from LRU. This is safe because uncharged page is expected not
2685 * to be reused (freed soon). Exception is SwapCache, it's handled by
2686 * special functions.
2689 unlock_page_cgroup(pc);
2691 * even after unlock, we have mem->res.usage here and this memcg
2692 * will never be freed.
2694 memcg_check_events(mem, page);
2695 if (do_swap_account && ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT) {
2696 mem_cgroup_swap_statistics(mem, true);
2697 mem_cgroup_get(mem);
2699 if (!mem_cgroup_is_root(mem))
2700 __do_uncharge(mem, ctype, page_size);
2705 unlock_page_cgroup(pc);
2709 void mem_cgroup_uncharge_page(struct page *page)
2712 if (page_mapped(page))
2714 if (page->mapping && !PageAnon(page))
2716 __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_MAPPED);
2719 void mem_cgroup_uncharge_cache_page(struct page *page)
2721 VM_BUG_ON(page_mapped(page));
2722 VM_BUG_ON(page->mapping);
2723 __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE);
2727 * Batch_start/batch_end is called in unmap_page_range/invlidate/trucate.
2728 * In that cases, pages are freed continuously and we can expect pages
2729 * are in the same memcg. All these calls itself limits the number of
2730 * pages freed at once, then uncharge_start/end() is called properly.
2731 * This may be called prural(2) times in a context,
2734 void mem_cgroup_uncharge_start(void)
2736 current->memcg_batch.do_batch++;
2737 /* We can do nest. */
2738 if (current->memcg_batch.do_batch == 1) {
2739 current->memcg_batch.memcg = NULL;
2740 current->memcg_batch.bytes = 0;
2741 current->memcg_batch.memsw_bytes = 0;
2745 void mem_cgroup_uncharge_end(void)
2747 struct memcg_batch_info *batch = ¤t->memcg_batch;
2749 if (!batch->do_batch)
2753 if (batch->do_batch) /* If stacked, do nothing. */
2759 * This "batch->memcg" is valid without any css_get/put etc...
2760 * bacause we hide charges behind us.
2763 res_counter_uncharge(&batch->memcg->res, batch->bytes);
2764 if (batch->memsw_bytes)
2765 res_counter_uncharge(&batch->memcg->memsw, batch->memsw_bytes);
2766 memcg_oom_recover(batch->memcg);
2767 /* forget this pointer (for sanity check) */
2768 batch->memcg = NULL;
2773 * called after __delete_from_swap_cache() and drop "page" account.
2774 * memcg information is recorded to swap_cgroup of "ent"
2777 mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout)
2779 struct mem_cgroup *memcg;
2780 int ctype = MEM_CGROUP_CHARGE_TYPE_SWAPOUT;
2782 if (!swapout) /* this was a swap cache but the swap is unused ! */
2783 ctype = MEM_CGROUP_CHARGE_TYPE_DROP;
2785 memcg = __mem_cgroup_uncharge_common(page, ctype);
2788 * record memcg information, if swapout && memcg != NULL,
2789 * mem_cgroup_get() was called in uncharge().
2791 if (do_swap_account && swapout && memcg)
2792 swap_cgroup_record(ent, css_id(&memcg->css));
2796 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
2798 * called from swap_entry_free(). remove record in swap_cgroup and
2799 * uncharge "memsw" account.
2801 void mem_cgroup_uncharge_swap(swp_entry_t ent)
2803 struct mem_cgroup *memcg;
2806 if (!do_swap_account)
2809 id = swap_cgroup_record(ent, 0);
2811 memcg = mem_cgroup_lookup(id);
2814 * We uncharge this because swap is freed.
2815 * This memcg can be obsolete one. We avoid calling css_tryget
2817 if (!mem_cgroup_is_root(memcg))
2818 res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
2819 mem_cgroup_swap_statistics(memcg, false);
2820 mem_cgroup_put(memcg);
2826 * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record.
2827 * @entry: swap entry to be moved
2828 * @from: mem_cgroup which the entry is moved from
2829 * @to: mem_cgroup which the entry is moved to
2830 * @need_fixup: whether we should fixup res_counters and refcounts.
2832 * It succeeds only when the swap_cgroup's record for this entry is the same
2833 * as the mem_cgroup's id of @from.
2835 * Returns 0 on success, -EINVAL on failure.
2837 * The caller must have charged to @to, IOW, called res_counter_charge() about
2838 * both res and memsw, and called css_get().
2840 static int mem_cgroup_move_swap_account(swp_entry_t entry,
2841 struct mem_cgroup *from, struct mem_cgroup *to, bool need_fixup)
2843 unsigned short old_id, new_id;
2845 old_id = css_id(&from->css);
2846 new_id = css_id(&to->css);
2848 if (swap_cgroup_cmpxchg(entry, old_id, new_id) == old_id) {
2849 mem_cgroup_swap_statistics(from, false);
2850 mem_cgroup_swap_statistics(to, true);
2852 * This function is only called from task migration context now.
2853 * It postpones res_counter and refcount handling till the end
2854 * of task migration(mem_cgroup_clear_mc()) for performance
2855 * improvement. But we cannot postpone mem_cgroup_get(to)
2856 * because if the process that has been moved to @to does
2857 * swap-in, the refcount of @to might be decreased to 0.
2861 if (!mem_cgroup_is_root(from))
2862 res_counter_uncharge(&from->memsw, PAGE_SIZE);
2863 mem_cgroup_put(from);
2865 * we charged both to->res and to->memsw, so we should
2868 if (!mem_cgroup_is_root(to))
2869 res_counter_uncharge(&to->res, PAGE_SIZE);
2876 static inline int mem_cgroup_move_swap_account(swp_entry_t entry,
2877 struct mem_cgroup *from, struct mem_cgroup *to, bool need_fixup)
2884 * Before starting migration, account PAGE_SIZE to mem_cgroup that the old
2887 int mem_cgroup_prepare_migration(struct page *page,
2888 struct page *newpage, struct mem_cgroup **ptr, gfp_t gfp_mask)
2890 struct page_cgroup *pc;
2891 struct mem_cgroup *mem = NULL;
2892 enum charge_type ctype;
2897 VM_BUG_ON(PageTransHuge(page));
2898 if (mem_cgroup_disabled())
2901 pc = lookup_page_cgroup(page);
2902 lock_page_cgroup(pc);
2903 if (PageCgroupUsed(pc)) {
2904 mem = pc->mem_cgroup;
2907 * At migrating an anonymous page, its mapcount goes down
2908 * to 0 and uncharge() will be called. But, even if it's fully
2909 * unmapped, migration may fail and this page has to be
2910 * charged again. We set MIGRATION flag here and delay uncharge
2911 * until end_migration() is called
2913 * Corner Case Thinking
2915 * When the old page was mapped as Anon and it's unmap-and-freed
2916 * while migration was ongoing.
2917 * If unmap finds the old page, uncharge() of it will be delayed
2918 * until end_migration(). If unmap finds a new page, it's
2919 * uncharged when it make mapcount to be 1->0. If unmap code
2920 * finds swap_migration_entry, the new page will not be mapped
2921 * and end_migration() will find it(mapcount==0).
2924 * When the old page was mapped but migraion fails, the kernel
2925 * remaps it. A charge for it is kept by MIGRATION flag even
2926 * if mapcount goes down to 0. We can do remap successfully
2927 * without charging it again.
2930 * The "old" page is under lock_page() until the end of
2931 * migration, so, the old page itself will not be swapped-out.
2932 * If the new page is swapped out before end_migraton, our
2933 * hook to usual swap-out path will catch the event.
2936 SetPageCgroupMigration(pc);
2938 unlock_page_cgroup(pc);
2940 * If the page is not charged at this point,
2947 ret = __mem_cgroup_try_charge(NULL, gfp_mask, ptr, false, PAGE_SIZE);
2948 css_put(&mem->css);/* drop extra refcnt */
2949 if (ret || *ptr == NULL) {
2950 if (PageAnon(page)) {
2951 lock_page_cgroup(pc);
2952 ClearPageCgroupMigration(pc);
2953 unlock_page_cgroup(pc);
2955 * The old page may be fully unmapped while we kept it.
2957 mem_cgroup_uncharge_page(page);
2962 * We charge new page before it's used/mapped. So, even if unlock_page()
2963 * is called before end_migration, we can catch all events on this new
2964 * page. In the case new page is migrated but not remapped, new page's
2965 * mapcount will be finally 0 and we call uncharge in end_migration().
2967 pc = lookup_page_cgroup(newpage);
2969 ctype = MEM_CGROUP_CHARGE_TYPE_MAPPED;
2970 else if (page_is_file_cache(page))
2971 ctype = MEM_CGROUP_CHARGE_TYPE_CACHE;
2973 ctype = MEM_CGROUP_CHARGE_TYPE_SHMEM;
2974 __mem_cgroup_commit_charge(mem, pc, ctype, PAGE_SIZE);
2978 /* remove redundant charge if migration failed*/
2979 void mem_cgroup_end_migration(struct mem_cgroup *mem,
2980 struct page *oldpage, struct page *newpage, bool migration_ok)
2982 struct page *used, *unused;
2983 struct page_cgroup *pc;
2987 /* blocks rmdir() */
2988 cgroup_exclude_rmdir(&mem->css);
2989 if (!migration_ok) {
2997 * We disallowed uncharge of pages under migration because mapcount
2998 * of the page goes down to zero, temporarly.
2999 * Clear the flag and check the page should be charged.
3001 pc = lookup_page_cgroup(oldpage);
3002 lock_page_cgroup(pc);
3003 ClearPageCgroupMigration(pc);
3004 unlock_page_cgroup(pc);
3006 __mem_cgroup_uncharge_common(unused, MEM_CGROUP_CHARGE_TYPE_FORCE);
3009 * If a page is a file cache, radix-tree replacement is very atomic
3010 * and we can skip this check. When it was an Anon page, its mapcount
3011 * goes down to 0. But because we added MIGRATION flage, it's not
3012 * uncharged yet. There are several case but page->mapcount check
3013 * and USED bit check in mem_cgroup_uncharge_page() will do enough
3014 * check. (see prepare_charge() also)
3017 mem_cgroup_uncharge_page(used);
3019 * At migration, we may charge account against cgroup which has no
3021 * So, rmdir()->pre_destroy() can be called while we do this charge.
3022 * In that case, we need to call pre_destroy() again. check it here.
3024 cgroup_release_and_wakeup_rmdir(&mem->css);
3028 * A call to try to shrink memory usage on charge failure at shmem's swapin.
3029 * Calling hierarchical_reclaim is not enough because we should update
3030 * last_oom_jiffies to prevent pagefault_out_of_memory from invoking global OOM.
3031 * Moreover considering hierarchy, we should reclaim from the mem_over_limit,
3032 * not from the memcg which this page would be charged to.
3033 * try_charge_swapin does all of these works properly.
3035 int mem_cgroup_shmem_charge_fallback(struct page *page,
3036 struct mm_struct *mm,
3039 struct mem_cgroup *mem;
3042 if (mem_cgroup_disabled())
3045 ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &mem);
3047 mem_cgroup_cancel_charge_swapin(mem); /* it does !mem check */
3052 static DEFINE_MUTEX(set_limit_mutex);
3054 static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
3055 unsigned long long val)
3058 u64 memswlimit, memlimit;
3060 int children = mem_cgroup_count_children(memcg);
3061 u64 curusage, oldusage;
3065 * For keeping hierarchical_reclaim simple, how long we should retry
3066 * is depends on callers. We set our retry-count to be function
3067 * of # of children which we should visit in this loop.
3069 retry_count = MEM_CGROUP_RECLAIM_RETRIES * children;
3071 oldusage = res_counter_read_u64(&memcg->res, RES_USAGE);
3074 while (retry_count) {
3075 if (signal_pending(current)) {
3080 * Rather than hide all in some function, I do this in
3081 * open coded manner. You see what this really does.
3082 * We have to guarantee mem->res.limit < mem->memsw.limit.
3084 mutex_lock(&set_limit_mutex);
3085 memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
3086 if (memswlimit < val) {
3088 mutex_unlock(&set_limit_mutex);
3092 memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT);
3096 ret = res_counter_set_limit(&memcg->res, val);
3098 if (memswlimit == val)
3099 memcg->memsw_is_minimum = true;
3101 memcg->memsw_is_minimum = false;
3103 mutex_unlock(&set_limit_mutex);
3108 mem_cgroup_hierarchical_reclaim(memcg, NULL, GFP_KERNEL,
3109 MEM_CGROUP_RECLAIM_SHRINK);
3110 curusage = res_counter_read_u64(&memcg->res, RES_USAGE);
3111 /* Usage is reduced ? */
3112 if (curusage >= oldusage)
3115 oldusage = curusage;
3117 if (!ret && enlarge)
3118 memcg_oom_recover(memcg);
3123 static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
3124 unsigned long long val)
3127 u64 memlimit, memswlimit, oldusage, curusage;
3128 int children = mem_cgroup_count_children(memcg);
3132 /* see mem_cgroup_resize_res_limit */
3133 retry_count = children * MEM_CGROUP_RECLAIM_RETRIES;
3134 oldusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
3135 while (retry_count) {
3136 if (signal_pending(current)) {
3141 * Rather than hide all in some function, I do this in
3142 * open coded manner. You see what this really does.
3143 * We have to guarantee mem->res.limit < mem->memsw.limit.
3145 mutex_lock(&set_limit_mutex);
3146 memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT);
3147 if (memlimit > val) {
3149 mutex_unlock(&set_limit_mutex);
3152 memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
3153 if (memswlimit < val)
3155 ret = res_counter_set_limit(&memcg->memsw, val);
3157 if (memlimit == val)
3158 memcg->memsw_is_minimum = true;
3160 memcg->memsw_is_minimum = false;
3162 mutex_unlock(&set_limit_mutex);
3167 mem_cgroup_hierarchical_reclaim(memcg, NULL, GFP_KERNEL,
3168 MEM_CGROUP_RECLAIM_NOSWAP |
3169 MEM_CGROUP_RECLAIM_SHRINK);
3170 curusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
3171 /* Usage is reduced ? */
3172 if (curusage >= oldusage)
3175 oldusage = curusage;
3177 if (!ret && enlarge)
3178 memcg_oom_recover(memcg);
3182 unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
3185 unsigned long nr_reclaimed = 0;
3186 struct mem_cgroup_per_zone *mz, *next_mz = NULL;
3187 unsigned long reclaimed;
3189 struct mem_cgroup_tree_per_zone *mctz;
3190 unsigned long long excess;
3195 mctz = soft_limit_tree_node_zone(zone_to_nid(zone), zone_idx(zone));
3197 * This loop can run a while, specially if mem_cgroup's continuously
3198 * keep exceeding their soft limit and putting the system under
3205 mz = mem_cgroup_largest_soft_limit_node(mctz);
3209 reclaimed = mem_cgroup_hierarchical_reclaim(mz->mem, zone,
3211 MEM_CGROUP_RECLAIM_SOFT);
3212 nr_reclaimed += reclaimed;
3213 spin_lock(&mctz->lock);
3216 * If we failed to reclaim anything from this memory cgroup
3217 * it is time to move on to the next cgroup
3223 * Loop until we find yet another one.
3225 * By the time we get the soft_limit lock
3226 * again, someone might have aded the
3227 * group back on the RB tree. Iterate to
3228 * make sure we get a different mem.
3229 * mem_cgroup_largest_soft_limit_node returns
3230 * NULL if no other cgroup is present on
3234 __mem_cgroup_largest_soft_limit_node(mctz);
3235 if (next_mz == mz) {
3236 css_put(&next_mz->mem->css);
3238 } else /* next_mz == NULL or other memcg */
3242 __mem_cgroup_remove_exceeded(mz->mem, mz, mctz);
3243 excess = res_counter_soft_limit_excess(&mz->mem->res);
3245 * One school of thought says that we should not add
3246 * back the node to the tree if reclaim returns 0.
3247 * But our reclaim could return 0, simply because due
3248 * to priority we are exposing a smaller subset of
3249 * memory to reclaim from. Consider this as a longer
3252 /* If excess == 0, no tree ops */
3253 __mem_cgroup_insert_exceeded(mz->mem, mz, mctz, excess);
3254 spin_unlock(&mctz->lock);
3255 css_put(&mz->mem->css);
3258 * Could not reclaim anything and there are no more
3259 * mem cgroups to try or we seem to be looping without
3260 * reclaiming anything.
3262 if (!nr_reclaimed &&
3264 loop > MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS))
3266 } while (!nr_reclaimed);
3268 css_put(&next_mz->mem->css);
3269 return nr_reclaimed;
3273 * This routine traverse page_cgroup in given list and drop them all.
3274 * *And* this routine doesn't reclaim page itself, just removes page_cgroup.
3276 static int mem_cgroup_force_empty_list(struct mem_cgroup *mem,
3277 int node, int zid, enum lru_list lru)
3280 struct mem_cgroup_per_zone *mz;
3281 struct page_cgroup *pc, *busy;
3282 unsigned long flags, loop;
3283 struct list_head *list;
3286 zone = &NODE_DATA(node)->node_zones[zid];
3287 mz = mem_cgroup_zoneinfo(mem, node, zid);
3288 list = &mz->lists[lru];
3290 loop = MEM_CGROUP_ZSTAT(mz, lru);
3291 /* give some margin against EBUSY etc...*/
3296 spin_lock_irqsave(&zone->lru_lock, flags);
3297 if (list_empty(list)) {
3298 spin_unlock_irqrestore(&zone->lru_lock, flags);
3301 pc = list_entry(list->prev, struct page_cgroup, lru);
3303 list_move(&pc->lru, list);
3305 spin_unlock_irqrestore(&zone->lru_lock, flags);
3308 spin_unlock_irqrestore(&zone->lru_lock, flags);
3310 ret = mem_cgroup_move_parent(pc, mem, GFP_KERNEL);
3314 if (ret == -EBUSY || ret == -EINVAL) {
3315 /* found lock contention or "pc" is obsolete. */
3322 if (!ret && !list_empty(list))
3328 * make mem_cgroup's charge to be 0 if there is no task.
3329 * This enables deleting this mem_cgroup.
3331 static int mem_cgroup_force_empty(struct mem_cgroup *mem, bool free_all)
3334 int node, zid, shrink;
3335 int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
3336 struct cgroup *cgrp = mem->css.cgroup;
3341 /* should free all ? */
3347 if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children))
3350 if (signal_pending(current))
3352 /* This is for making all *used* pages to be on LRU. */
3353 lru_add_drain_all();
3354 drain_all_stock_sync();
3356 mem_cgroup_start_move(mem);
3357 for_each_node_state(node, N_HIGH_MEMORY) {
3358 for (zid = 0; !ret && zid < MAX_NR_ZONES; zid++) {
3361 ret = mem_cgroup_force_empty_list(mem,
3370 mem_cgroup_end_move(mem);
3371 memcg_oom_recover(mem);
3372 /* it seems parent cgroup doesn't have enough mem */
3376 /* "ret" should also be checked to ensure all lists are empty. */
3377 } while (mem->res.usage > 0 || ret);
3383 /* returns EBUSY if there is a task or if we come here twice. */
3384 if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children) || shrink) {
3388 /* we call try-to-free pages for make this cgroup empty */
3389 lru_add_drain_all();
3390 /* try to free all pages in this cgroup */
3392 while (nr_retries && mem->res.usage > 0) {
3395 if (signal_pending(current)) {
3399 progress = try_to_free_mem_cgroup_pages(mem, GFP_KERNEL,
3400 false, get_swappiness(mem));
3403 /* maybe some writeback is necessary */
3404 congestion_wait(BLK_RW_ASYNC, HZ/10);
3409 /* try move_account...there may be some *locked* pages. */
3413 int mem_cgroup_force_empty_write(struct cgroup *cont, unsigned int event)
3415 return mem_cgroup_force_empty(mem_cgroup_from_cont(cont), true);
3419 static u64 mem_cgroup_hierarchy_read(struct cgroup *cont, struct cftype *cft)
3421 return mem_cgroup_from_cont(cont)->use_hierarchy;
3424 static int mem_cgroup_hierarchy_write(struct cgroup *cont, struct cftype *cft,
3428 struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
3429 struct cgroup *parent = cont->parent;
3430 struct mem_cgroup *parent_mem = NULL;
3433 parent_mem = mem_cgroup_from_cont(parent);
3437 * If parent's use_hierarchy is set, we can't make any modifications
3438 * in the child subtrees. If it is unset, then the change can
3439 * occur, provided the current cgroup has no children.
3441 * For the root cgroup, parent_mem is NULL, we allow value to be
3442 * set if there are no children.
3444 if ((!parent_mem || !parent_mem->use_hierarchy) &&
3445 (val == 1 || val == 0)) {
3446 if (list_empty(&cont->children))
3447 mem->use_hierarchy = val;
3458 static u64 mem_cgroup_get_recursive_idx_stat(struct mem_cgroup *mem,
3459 enum mem_cgroup_stat_index idx)
3461 struct mem_cgroup *iter;
3464 /* each per cpu's value can be minus.Then, use s64 */
3465 for_each_mem_cgroup_tree(iter, mem)
3466 val += mem_cgroup_read_stat(iter, idx);
3468 if (val < 0) /* race ? */
3473 static inline u64 mem_cgroup_usage(struct mem_cgroup *mem, bool swap)
3477 if (!mem_cgroup_is_root(mem)) {
3479 return res_counter_read_u64(&mem->res, RES_USAGE);
3481 return res_counter_read_u64(&mem->memsw, RES_USAGE);
3484 val = mem_cgroup_get_recursive_idx_stat(mem, MEM_CGROUP_STAT_CACHE);
3485 val += mem_cgroup_get_recursive_idx_stat(mem, MEM_CGROUP_STAT_RSS);
3488 val += mem_cgroup_get_recursive_idx_stat(mem,
3489 MEM_CGROUP_STAT_SWAPOUT);
3491 return val << PAGE_SHIFT;
3494 static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft)
3496 struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
3500 type = MEMFILE_TYPE(cft->private);
3501 name = MEMFILE_ATTR(cft->private);
3504 if (name == RES_USAGE)
3505 val = mem_cgroup_usage(mem, false);
3507 val = res_counter_read_u64(&mem->res, name);
3510 if (name == RES_USAGE)
3511 val = mem_cgroup_usage(mem, true);
3513 val = res_counter_read_u64(&mem->memsw, name);
3522 * The user of this function is...
3525 static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
3528 struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
3530 unsigned long long val;
3533 type = MEMFILE_TYPE(cft->private);
3534 name = MEMFILE_ATTR(cft->private);
3537 if (mem_cgroup_is_root(memcg)) { /* Can't set limit on root */
3541 /* This function does all necessary parse...reuse it */
3542 ret = res_counter_memparse_write_strategy(buffer, &val);
3546 ret = mem_cgroup_resize_limit(memcg, val);
3548 ret = mem_cgroup_resize_memsw_limit(memcg, val);
3550 case RES_SOFT_LIMIT:
3551 ret = res_counter_memparse_write_strategy(buffer, &val);
3555 * For memsw, soft limits are hard to implement in terms
3556 * of semantics, for now, we support soft limits for
3557 * control without swap
3560 ret = res_counter_set_soft_limit(&memcg->res, val);
3565 ret = -EINVAL; /* should be BUG() ? */
3571 static void memcg_get_hierarchical_limit(struct mem_cgroup *memcg,
3572 unsigned long long *mem_limit, unsigned long long *memsw_limit)
3574 struct cgroup *cgroup;
3575 unsigned long long min_limit, min_memsw_limit, tmp;
3577 min_limit = res_counter_read_u64(&memcg->res, RES_LIMIT);
3578 min_memsw_limit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
3579 cgroup = memcg->css.cgroup;
3580 if (!memcg->use_hierarchy)
3583 while (cgroup->parent) {
3584 cgroup = cgroup->parent;
3585 memcg = mem_cgroup_from_cont(cgroup);
3586 if (!memcg->use_hierarchy)
3588 tmp = res_counter_read_u64(&memcg->res, RES_LIMIT);
3589 min_limit = min(min_limit, tmp);
3590 tmp = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
3591 min_memsw_limit = min(min_memsw_limit, tmp);
3594 *mem_limit = min_limit;
3595 *memsw_limit = min_memsw_limit;
3599 static int mem_cgroup_reset(struct cgroup *cont, unsigned int event)
3601 struct mem_cgroup *mem;
3604 mem = mem_cgroup_from_cont(cont);
3605 type = MEMFILE_TYPE(event);
3606 name = MEMFILE_ATTR(event);
3610 res_counter_reset_max(&mem->res);
3612 res_counter_reset_max(&mem->memsw);
3616 res_counter_reset_failcnt(&mem->res);
3618 res_counter_reset_failcnt(&mem->memsw);
3625 static u64 mem_cgroup_move_charge_read(struct cgroup *cgrp,
3628 return mem_cgroup_from_cont(cgrp)->move_charge_at_immigrate;
3632 static int mem_cgroup_move_charge_write(struct cgroup *cgrp,
3633 struct cftype *cft, u64 val)
3635 struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp);
3637 if (val >= (1 << NR_MOVE_TYPE))
3640 * We check this value several times in both in can_attach() and
3641 * attach(), so we need cgroup lock to prevent this value from being
3645 mem->move_charge_at_immigrate = val;
3651 static int mem_cgroup_move_charge_write(struct cgroup *cgrp,
3652 struct cftype *cft, u64 val)
3659 /* For read statistics */
3675 struct mcs_total_stat {
3676 s64 stat[NR_MCS_STAT];
3682 } memcg_stat_strings[NR_MCS_STAT] = {
3683 {"cache", "total_cache"},
3684 {"rss", "total_rss"},
3685 {"mapped_file", "total_mapped_file"},
3686 {"pgpgin", "total_pgpgin"},
3687 {"pgpgout", "total_pgpgout"},
3688 {"swap", "total_swap"},
3689 {"inactive_anon", "total_inactive_anon"},
3690 {"active_anon", "total_active_anon"},
3691 {"inactive_file", "total_inactive_file"},
3692 {"active_file", "total_active_file"},
3693 {"unevictable", "total_unevictable"}
3698 mem_cgroup_get_local_stat(struct mem_cgroup *mem, struct mcs_total_stat *s)
3703 val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_CACHE);
3704 s->stat[MCS_CACHE] += val * PAGE_SIZE;
3705 val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_RSS);
3706 s->stat[MCS_RSS] += val * PAGE_SIZE;
3707 val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_FILE_MAPPED);
3708 s->stat[MCS_FILE_MAPPED] += val * PAGE_SIZE;
3709 val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_PGPGIN_COUNT);
3710 s->stat[MCS_PGPGIN] += val;
3711 val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_PGPGOUT_COUNT);
3712 s->stat[MCS_PGPGOUT] += val;
3713 if (do_swap_account) {
3714 val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_SWAPOUT);
3715 s->stat[MCS_SWAP] += val * PAGE_SIZE;
3719 val = mem_cgroup_get_local_zonestat(mem, LRU_INACTIVE_ANON);
3720 s->stat[MCS_INACTIVE_ANON] += val * PAGE_SIZE;
3721 val = mem_cgroup_get_local_zonestat(mem, LRU_ACTIVE_ANON);
3722 s->stat[MCS_ACTIVE_ANON] += val * PAGE_SIZE;
3723 val = mem_cgroup_get_local_zonestat(mem, LRU_INACTIVE_FILE);
3724 s->stat[MCS_INACTIVE_FILE] += val * PAGE_SIZE;
3725 val = mem_cgroup_get_local_zonestat(mem, LRU_ACTIVE_FILE);
3726 s->stat[MCS_ACTIVE_FILE] += val * PAGE_SIZE;
3727 val = mem_cgroup_get_local_zonestat(mem, LRU_UNEVICTABLE);
3728 s->stat[MCS_UNEVICTABLE] += val * PAGE_SIZE;
3732 mem_cgroup_get_total_stat(struct mem_cgroup *mem, struct mcs_total_stat *s)
3734 struct mem_cgroup *iter;
3736 for_each_mem_cgroup_tree(iter, mem)
3737 mem_cgroup_get_local_stat(iter, s);
3740 static int mem_control_stat_show(struct cgroup *cont, struct cftype *cft,
3741 struct cgroup_map_cb *cb)
3743 struct mem_cgroup *mem_cont = mem_cgroup_from_cont(cont);
3744 struct mcs_total_stat mystat;
3747 memset(&mystat, 0, sizeof(mystat));
3748 mem_cgroup_get_local_stat(mem_cont, &mystat);
3750 for (i = 0; i < NR_MCS_STAT; i++) {
3751 if (i == MCS_SWAP && !do_swap_account)
3753 cb->fill(cb, memcg_stat_strings[i].local_name, mystat.stat[i]);
3756 /* Hierarchical information */
3758 unsigned long long limit, memsw_limit;
3759 memcg_get_hierarchical_limit(mem_cont, &limit, &memsw_limit);
3760 cb->fill(cb, "hierarchical_memory_limit", limit);
3761 if (do_swap_account)
3762 cb->fill(cb, "hierarchical_memsw_limit", memsw_limit);
3765 memset(&mystat, 0, sizeof(mystat));
3766 mem_cgroup_get_total_stat(mem_cont, &mystat);
3767 for (i = 0; i < NR_MCS_STAT; i++) {
3768 if (i == MCS_SWAP && !do_swap_account)
3770 cb->fill(cb, memcg_stat_strings[i].total_name, mystat.stat[i]);
3773 #ifdef CONFIG_DEBUG_VM
3774 cb->fill(cb, "inactive_ratio", calc_inactive_ratio(mem_cont, NULL));
3778 struct mem_cgroup_per_zone *mz;
3779 unsigned long recent_rotated[2] = {0, 0};
3780 unsigned long recent_scanned[2] = {0, 0};
3782 for_each_online_node(nid)
3783 for (zid = 0; zid < MAX_NR_ZONES; zid++) {
3784 mz = mem_cgroup_zoneinfo(mem_cont, nid, zid);
3786 recent_rotated[0] +=
3787 mz->reclaim_stat.recent_rotated[0];
3788 recent_rotated[1] +=
3789 mz->reclaim_stat.recent_rotated[1];
3790 recent_scanned[0] +=
3791 mz->reclaim_stat.recent_scanned[0];
3792 recent_scanned[1] +=
3793 mz->reclaim_stat.recent_scanned[1];
3795 cb->fill(cb, "recent_rotated_anon", recent_rotated[0]);
3796 cb->fill(cb, "recent_rotated_file", recent_rotated[1]);
3797 cb->fill(cb, "recent_scanned_anon", recent_scanned[0]);
3798 cb->fill(cb, "recent_scanned_file", recent_scanned[1]);
3805 static u64 mem_cgroup_swappiness_read(struct cgroup *cgrp, struct cftype *cft)
3807 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
3809 return get_swappiness(memcg);
3812 static int mem_cgroup_swappiness_write(struct cgroup *cgrp, struct cftype *cft,
3815 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
3816 struct mem_cgroup *parent;
3821 if (cgrp->parent == NULL)
3824 parent = mem_cgroup_from_cont(cgrp->parent);
3828 /* If under hierarchy, only empty-root can set this value */
3829 if ((parent->use_hierarchy) ||
3830 (memcg->use_hierarchy && !list_empty(&cgrp->children))) {
3835 spin_lock(&memcg->reclaim_param_lock);
3836 memcg->swappiness = val;
3837 spin_unlock(&memcg->reclaim_param_lock);
3844 static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap)
3846 struct mem_cgroup_threshold_ary *t;
3852 t = rcu_dereference(memcg->thresholds.primary);
3854 t = rcu_dereference(memcg->memsw_thresholds.primary);
3859 usage = mem_cgroup_usage(memcg, swap);
3862 * current_threshold points to threshold just below usage.
3863 * If it's not true, a threshold was crossed after last
3864 * call of __mem_cgroup_threshold().
3866 i = t->current_threshold;
3869 * Iterate backward over array of thresholds starting from
3870 * current_threshold and check if a threshold is crossed.
3871 * If none of thresholds below usage is crossed, we read
3872 * only one element of the array here.
3874 for (; i >= 0 && unlikely(t->entries[i].threshold > usage); i--)
3875 eventfd_signal(t->entries[i].eventfd, 1);
3877 /* i = current_threshold + 1 */
3881 * Iterate forward over array of thresholds starting from
3882 * current_threshold+1 and check if a threshold is crossed.
3883 * If none of thresholds above usage is crossed, we read
3884 * only one element of the array here.
3886 for (; i < t->size && unlikely(t->entries[i].threshold <= usage); i++)
3887 eventfd_signal(t->entries[i].eventfd, 1);
3889 /* Update current_threshold */
3890 t->current_threshold = i - 1;
3895 static void mem_cgroup_threshold(struct mem_cgroup *memcg)
3898 __mem_cgroup_threshold(memcg, false);
3899 if (do_swap_account)
3900 __mem_cgroup_threshold(memcg, true);
3902 memcg = parent_mem_cgroup(memcg);
3906 static int compare_thresholds(const void *a, const void *b)
3908 const struct mem_cgroup_threshold *_a = a;
3909 const struct mem_cgroup_threshold *_b = b;
3911 return _a->threshold - _b->threshold;
3914 static int mem_cgroup_oom_notify_cb(struct mem_cgroup *mem)
3916 struct mem_cgroup_eventfd_list *ev;
3918 list_for_each_entry(ev, &mem->oom_notify, list)
3919 eventfd_signal(ev->eventfd, 1);
3923 static void mem_cgroup_oom_notify(struct mem_cgroup *mem)
3925 struct mem_cgroup *iter;
3927 for_each_mem_cgroup_tree(iter, mem)
3928 mem_cgroup_oom_notify_cb(iter);
3931 static int mem_cgroup_usage_register_event(struct cgroup *cgrp,
3932 struct cftype *cft, struct eventfd_ctx *eventfd, const char *args)
3934 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
3935 struct mem_cgroup_thresholds *thresholds;
3936 struct mem_cgroup_threshold_ary *new;
3937 int type = MEMFILE_TYPE(cft->private);
3938 u64 threshold, usage;
3941 ret = res_counter_memparse_write_strategy(args, &threshold);
3945 mutex_lock(&memcg->thresholds_lock);
3948 thresholds = &memcg->thresholds;
3949 else if (type == _MEMSWAP)
3950 thresholds = &memcg->memsw_thresholds;
3954 usage = mem_cgroup_usage(memcg, type == _MEMSWAP);
3956 /* Check if a threshold crossed before adding a new one */
3957 if (thresholds->primary)
3958 __mem_cgroup_threshold(memcg, type == _MEMSWAP);
3960 size = thresholds->primary ? thresholds->primary->size + 1 : 1;
3962 /* Allocate memory for new array of thresholds */
3963 new = kmalloc(sizeof(*new) + size * sizeof(struct mem_cgroup_threshold),
3971 /* Copy thresholds (if any) to new array */
3972 if (thresholds->primary) {
3973 memcpy(new->entries, thresholds->primary->entries, (size - 1) *
3974 sizeof(struct mem_cgroup_threshold));
3977 /* Add new threshold */
3978 new->entries[size - 1].eventfd = eventfd;
3979 new->entries[size - 1].threshold = threshold;
3981 /* Sort thresholds. Registering of new threshold isn't time-critical */
3982 sort(new->entries, size, sizeof(struct mem_cgroup_threshold),
3983 compare_thresholds, NULL);
3985 /* Find current threshold */
3986 new->current_threshold = -1;
3987 for (i = 0; i < size; i++) {
3988 if (new->entries[i].threshold < usage) {
3990 * new->current_threshold will not be used until
3991 * rcu_assign_pointer(), so it's safe to increment
3994 ++new->current_threshold;
3998 /* Free old spare buffer and save old primary buffer as spare */
3999 kfree(thresholds->spare);
4000 thresholds->spare = thresholds->primary;
4002 rcu_assign_pointer(thresholds->primary, new);
4004 /* To be sure that nobody uses thresholds */
4008 mutex_unlock(&memcg->thresholds_lock);
4013 static void mem_cgroup_usage_unregister_event(struct cgroup *cgrp,
4014 struct cftype *cft, struct eventfd_ctx *eventfd)
4016 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
4017 struct mem_cgroup_thresholds *thresholds;
4018 struct mem_cgroup_threshold_ary *new;
4019 int type = MEMFILE_TYPE(cft->private);
4023 mutex_lock(&memcg->thresholds_lock);
4025 thresholds = &memcg->thresholds;
4026 else if (type == _MEMSWAP)
4027 thresholds = &memcg->memsw_thresholds;
4032 * Something went wrong if we trying to unregister a threshold
4033 * if we don't have thresholds
4035 BUG_ON(!thresholds);
4037 usage = mem_cgroup_usage(memcg, type == _MEMSWAP);
4039 /* Check if a threshold crossed before removing */
4040 __mem_cgroup_threshold(memcg, type == _MEMSWAP);
4042 /* Calculate new number of threshold */
4044 for (i = 0; i < thresholds->primary->size; i++) {
4045 if (thresholds->primary->entries[i].eventfd != eventfd)
4049 new = thresholds->spare;
4051 /* Set thresholds array to NULL if we don't have thresholds */
4060 /* Copy thresholds and find current threshold */
4061 new->current_threshold = -1;
4062 for (i = 0, j = 0; i < thresholds->primary->size; i++) {
4063 if (thresholds->primary->entries[i].eventfd == eventfd)
4066 new->entries[j] = thresholds->primary->entries[i];
4067 if (new->entries[j].threshold < usage) {
4069 * new->current_threshold will not be used
4070 * until rcu_assign_pointer(), so it's safe to increment
4073 ++new->current_threshold;
4079 /* Swap primary and spare array */
4080 thresholds->spare = thresholds->primary;
4081 rcu_assign_pointer(thresholds->primary, new);
4083 /* To be sure that nobody uses thresholds */
4086 mutex_unlock(&memcg->thresholds_lock);
4089 static int mem_cgroup_oom_register_event(struct cgroup *cgrp,
4090 struct cftype *cft, struct eventfd_ctx *eventfd, const char *args)
4092 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
4093 struct mem_cgroup_eventfd_list *event;
4094 int type = MEMFILE_TYPE(cft->private);
4096 BUG_ON(type != _OOM_TYPE);
4097 event = kmalloc(sizeof(*event), GFP_KERNEL);
4101 mutex_lock(&memcg_oom_mutex);
4103 event->eventfd = eventfd;
4104 list_add(&event->list, &memcg->oom_notify);
4106 /* already in OOM ? */
4107 if (atomic_read(&memcg->oom_lock))
4108 eventfd_signal(eventfd, 1);
4109 mutex_unlock(&memcg_oom_mutex);
4114 static void mem_cgroup_oom_unregister_event(struct cgroup *cgrp,
4115 struct cftype *cft, struct eventfd_ctx *eventfd)
4117 struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp);
4118 struct mem_cgroup_eventfd_list *ev, *tmp;
4119 int type = MEMFILE_TYPE(cft->private);
4121 BUG_ON(type != _OOM_TYPE);
4123 mutex_lock(&memcg_oom_mutex);
4125 list_for_each_entry_safe(ev, tmp, &mem->oom_notify, list) {
4126 if (ev->eventfd == eventfd) {
4127 list_del(&ev->list);
4132 mutex_unlock(&memcg_oom_mutex);
4135 static int mem_cgroup_oom_control_read(struct cgroup *cgrp,
4136 struct cftype *cft, struct cgroup_map_cb *cb)
4138 struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp);
4140 cb->fill(cb, "oom_kill_disable", mem->oom_kill_disable);
4142 if (atomic_read(&mem->oom_lock))
4143 cb->fill(cb, "under_oom", 1);
4145 cb->fill(cb, "under_oom", 0);
4149 static int mem_cgroup_oom_control_write(struct cgroup *cgrp,
4150 struct cftype *cft, u64 val)
4152 struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp);
4153 struct mem_cgroup *parent;
4155 /* cannot set to root cgroup and only 0 and 1 are allowed */
4156 if (!cgrp->parent || !((val == 0) || (val == 1)))
4159 parent = mem_cgroup_from_cont(cgrp->parent);
4162 /* oom-kill-disable is a flag for subhierarchy. */
4163 if ((parent->use_hierarchy) ||
4164 (mem->use_hierarchy && !list_empty(&cgrp->children))) {
4168 mem->oom_kill_disable = val;
4170 memcg_oom_recover(mem);
4175 static struct cftype mem_cgroup_files[] = {
4177 .name = "usage_in_bytes",
4178 .private = MEMFILE_PRIVATE(_MEM, RES_USAGE),
4179 .read_u64 = mem_cgroup_read,
4180 .register_event = mem_cgroup_usage_register_event,
4181 .unregister_event = mem_cgroup_usage_unregister_event,
4184 .name = "max_usage_in_bytes",
4185 .private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE),
4186 .trigger = mem_cgroup_reset,
4187 .read_u64 = mem_cgroup_read,
4190 .name = "limit_in_bytes",
4191 .private = MEMFILE_PRIVATE(_MEM, RES_LIMIT),
4192 .write_string = mem_cgroup_write,
4193 .read_u64 = mem_cgroup_read,
4196 .name = "soft_limit_in_bytes",
4197 .private = MEMFILE_PRIVATE(_MEM, RES_SOFT_LIMIT),
4198 .write_string = mem_cgroup_write,
4199 .read_u64 = mem_cgroup_read,
4203 .private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT),
4204 .trigger = mem_cgroup_reset,
4205 .read_u64 = mem_cgroup_read,
4209 .read_map = mem_control_stat_show,
4212 .name = "force_empty",
4213 .trigger = mem_cgroup_force_empty_write,
4216 .name = "use_hierarchy",
4217 .write_u64 = mem_cgroup_hierarchy_write,
4218 .read_u64 = mem_cgroup_hierarchy_read,
4221 .name = "swappiness",
4222 .read_u64 = mem_cgroup_swappiness_read,
4223 .write_u64 = mem_cgroup_swappiness_write,
4226 .name = "move_charge_at_immigrate",
4227 .read_u64 = mem_cgroup_move_charge_read,
4228 .write_u64 = mem_cgroup_move_charge_write,
4231 .name = "oom_control",
4232 .read_map = mem_cgroup_oom_control_read,
4233 .write_u64 = mem_cgroup_oom_control_write,
4234 .register_event = mem_cgroup_oom_register_event,
4235 .unregister_event = mem_cgroup_oom_unregister_event,
4236 .private = MEMFILE_PRIVATE(_OOM_TYPE, OOM_CONTROL),
4240 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
4241 static struct cftype memsw_cgroup_files[] = {
4243 .name = "memsw.usage_in_bytes",
4244 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE),
4245 .read_u64 = mem_cgroup_read,
4246 .register_event = mem_cgroup_usage_register_event,
4247 .unregister_event = mem_cgroup_usage_unregister_event,
4250 .name = "memsw.max_usage_in_bytes",
4251 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE),
4252 .trigger = mem_cgroup_reset,
4253 .read_u64 = mem_cgroup_read,
4256 .name = "memsw.limit_in_bytes",
4257 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT),
4258 .write_string = mem_cgroup_write,
4259 .read_u64 = mem_cgroup_read,
4262 .name = "memsw.failcnt",
4263 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT),
4264 .trigger = mem_cgroup_reset,
4265 .read_u64 = mem_cgroup_read,
4269 static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss)
4271 if (!do_swap_account)
4273 return cgroup_add_files(cont, ss, memsw_cgroup_files,
4274 ARRAY_SIZE(memsw_cgroup_files));
4277 static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss)
4283 static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
4285 struct mem_cgroup_per_node *pn;
4286 struct mem_cgroup_per_zone *mz;
4288 int zone, tmp = node;
4290 * This routine is called against possible nodes.
4291 * But it's BUG to call kmalloc() against offline node.
4293 * TODO: this routine can waste much memory for nodes which will
4294 * never be onlined. It's better to use memory hotplug callback
4297 if (!node_state(node, N_NORMAL_MEMORY))
4299 pn = kzalloc_node(sizeof(*pn), GFP_KERNEL, tmp);
4303 mem->info.nodeinfo[node] = pn;
4304 for (zone = 0; zone < MAX_NR_ZONES; zone++) {
4305 mz = &pn->zoneinfo[zone];
4307 INIT_LIST_HEAD(&mz->lists[l]);
4308 mz->usage_in_excess = 0;
4309 mz->on_tree = false;
4315 static void free_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
4317 kfree(mem->info.nodeinfo[node]);
4320 static struct mem_cgroup *mem_cgroup_alloc(void)
4322 struct mem_cgroup *mem;
4323 int size = sizeof(struct mem_cgroup);
4325 /* Can be very big if MAX_NUMNODES is very big */
4326 if (size < PAGE_SIZE)
4327 mem = kzalloc(size, GFP_KERNEL);
4329 mem = vzalloc(size);
4334 mem->stat = alloc_percpu(struct mem_cgroup_stat_cpu);
4337 spin_lock_init(&mem->pcp_counter_lock);
4341 if (size < PAGE_SIZE)
4349 * At destroying mem_cgroup, references from swap_cgroup can remain.
4350 * (scanning all at force_empty is too costly...)
4352 * Instead of clearing all references at force_empty, we remember
4353 * the number of reference from swap_cgroup and free mem_cgroup when
4354 * it goes down to 0.
4356 * Removal of cgroup itself succeeds regardless of refs from swap.
4359 static void __mem_cgroup_free(struct mem_cgroup *mem)
4363 mem_cgroup_remove_from_trees(mem);
4364 free_css_id(&mem_cgroup_subsys, &mem->css);
4366 for_each_node_state(node, N_POSSIBLE)
4367 free_mem_cgroup_per_zone_info(mem, node);
4369 free_percpu(mem->stat);
4370 if (sizeof(struct mem_cgroup) < PAGE_SIZE)
4376 static void mem_cgroup_get(struct mem_cgroup *mem)
4378 atomic_inc(&mem->refcnt);
4381 static void __mem_cgroup_put(struct mem_cgroup *mem, int count)
4383 if (atomic_sub_and_test(count, &mem->refcnt)) {
4384 struct mem_cgroup *parent = parent_mem_cgroup(mem);
4385 __mem_cgroup_free(mem);
4387 mem_cgroup_put(parent);
4391 static void mem_cgroup_put(struct mem_cgroup *mem)
4393 __mem_cgroup_put(mem, 1);
4397 * Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled.
4399 static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem)
4401 if (!mem->res.parent)
4403 return mem_cgroup_from_res_counter(mem->res.parent, res);
4406 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
4407 static void __init enable_swap_cgroup(void)
4409 if (!mem_cgroup_disabled() && really_do_swap_account)
4410 do_swap_account = 1;
4413 static void __init enable_swap_cgroup(void)
4418 static int mem_cgroup_soft_limit_tree_init(void)
4420 struct mem_cgroup_tree_per_node *rtpn;
4421 struct mem_cgroup_tree_per_zone *rtpz;
4422 int tmp, node, zone;
4424 for_each_node_state(node, N_POSSIBLE) {
4426 if (!node_state(node, N_NORMAL_MEMORY))
4428 rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL, tmp);
4432 soft_limit_tree.rb_tree_per_node[node] = rtpn;
4434 for (zone = 0; zone < MAX_NR_ZONES; zone++) {
4435 rtpz = &rtpn->rb_tree_per_zone[zone];
4436 rtpz->rb_root = RB_ROOT;
4437 spin_lock_init(&rtpz->lock);
4443 static struct cgroup_subsys_state * __ref
4444 mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
4446 struct mem_cgroup *mem, *parent;
4447 long error = -ENOMEM;
4450 mem = mem_cgroup_alloc();
4452 return ERR_PTR(error);
4454 for_each_node_state(node, N_POSSIBLE)
4455 if (alloc_mem_cgroup_per_zone_info(mem, node))
4459 if (cont->parent == NULL) {
4461 enable_swap_cgroup();
4463 root_mem_cgroup = mem;
4464 if (mem_cgroup_soft_limit_tree_init())
4466 for_each_possible_cpu(cpu) {
4467 struct memcg_stock_pcp *stock =
4468 &per_cpu(memcg_stock, cpu);
4469 INIT_WORK(&stock->work, drain_local_stock);
4471 hotcpu_notifier(memcg_cpu_hotplug_callback, 0);
4473 parent = mem_cgroup_from_cont(cont->parent);
4474 mem->use_hierarchy = parent->use_hierarchy;
4475 mem->oom_kill_disable = parent->oom_kill_disable;
4478 if (parent && parent->use_hierarchy) {
4479 res_counter_init(&mem->res, &parent->res);
4480 res_counter_init(&mem->memsw, &parent->memsw);
4482 * We increment refcnt of the parent to ensure that we can
4483 * safely access it on res_counter_charge/uncharge.
4484 * This refcnt will be decremented when freeing this
4485 * mem_cgroup(see mem_cgroup_put).
4487 mem_cgroup_get(parent);
4489 res_counter_init(&mem->res, NULL);
4490 res_counter_init(&mem->memsw, NULL);
4492 mem->last_scanned_child = 0;
4493 spin_lock_init(&mem->reclaim_param_lock);
4494 INIT_LIST_HEAD(&mem->oom_notify);
4497 mem->swappiness = get_swappiness(parent);
4498 atomic_set(&mem->refcnt, 1);
4499 mem->move_charge_at_immigrate = 0;
4500 mutex_init(&mem->thresholds_lock);
4503 __mem_cgroup_free(mem);
4504 root_mem_cgroup = NULL;
4505 return ERR_PTR(error);
4508 static int mem_cgroup_pre_destroy(struct cgroup_subsys *ss,
4509 struct cgroup *cont)
4511 struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
4513 return mem_cgroup_force_empty(mem, false);
4516 static void mem_cgroup_destroy(struct cgroup_subsys *ss,
4517 struct cgroup *cont)
4519 struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
4521 mem_cgroup_put(mem);
4524 static int mem_cgroup_populate(struct cgroup_subsys *ss,
4525 struct cgroup *cont)
4529 ret = cgroup_add_files(cont, ss, mem_cgroup_files,
4530 ARRAY_SIZE(mem_cgroup_files));
4533 ret = register_memsw_files(cont, ss);
4538 /* Handlers for move charge at task migration. */
4539 #define PRECHARGE_COUNT_AT_ONCE 256
4540 static int mem_cgroup_do_precharge(unsigned long count)
4543 int batch_count = PRECHARGE_COUNT_AT_ONCE;
4544 struct mem_cgroup *mem = mc.to;
4546 if (mem_cgroup_is_root(mem)) {
4547 mc.precharge += count;
4548 /* we don't need css_get for root */
4551 /* try to charge at once */
4553 struct res_counter *dummy;
4555 * "mem" cannot be under rmdir() because we've already checked
4556 * by cgroup_lock_live_cgroup() that it is not removed and we
4557 * are still under the same cgroup_mutex. So we can postpone
4560 if (res_counter_charge(&mem->res, PAGE_SIZE * count, &dummy))
4562 if (do_swap_account && res_counter_charge(&mem->memsw,
4563 PAGE_SIZE * count, &dummy)) {
4564 res_counter_uncharge(&mem->res, PAGE_SIZE * count);
4567 mc.precharge += count;
4571 /* fall back to one by one charge */
4573 if (signal_pending(current)) {
4577 if (!batch_count--) {
4578 batch_count = PRECHARGE_COUNT_AT_ONCE;
4581 ret = __mem_cgroup_try_charge(NULL, GFP_KERNEL, &mem, false,
4584 /* mem_cgroup_clear_mc() will do uncharge later */
4592 * is_target_pte_for_mc - check a pte whether it is valid for move charge
4593 * @vma: the vma the pte to be checked belongs
4594 * @addr: the address corresponding to the pte to be checked
4595 * @ptent: the pte to be checked
4596 * @target: the pointer the target page or swap ent will be stored(can be NULL)
4599 * 0(MC_TARGET_NONE): if the pte is not a target for move charge.
4600 * 1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for
4601 * move charge. if @target is not NULL, the page is stored in target->page
4602 * with extra refcnt got(Callers should handle it).
4603 * 2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a
4604 * target for charge migration. if @target is not NULL, the entry is stored
4607 * Called with pte lock held.
4614 enum mc_target_type {
4615 MC_TARGET_NONE, /* not used */
4620 static struct page *mc_handle_present_pte(struct vm_area_struct *vma,
4621 unsigned long addr, pte_t ptent)
4623 struct page *page = vm_normal_page(vma, addr, ptent);
4625 if (!page || !page_mapped(page))
4627 if (PageAnon(page)) {
4628 /* we don't move shared anon */
4629 if (!move_anon() || page_mapcount(page) > 2)
4631 } else if (!move_file())
4632 /* we ignore mapcount for file pages */
4634 if (!get_page_unless_zero(page))
4640 static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
4641 unsigned long addr, pte_t ptent, swp_entry_t *entry)
4644 struct page *page = NULL;
4645 swp_entry_t ent = pte_to_swp_entry(ptent);
4647 if (!move_anon() || non_swap_entry(ent))
4649 usage_count = mem_cgroup_count_swap_user(ent, &page);
4650 if (usage_count > 1) { /* we don't move shared anon */
4655 if (do_swap_account)
4656 entry->val = ent.val;
4661 static struct page *mc_handle_file_pte(struct vm_area_struct *vma,
4662 unsigned long addr, pte_t ptent, swp_entry_t *entry)
4664 struct page *page = NULL;
4665 struct inode *inode;
4666 struct address_space *mapping;
4669 if (!vma->vm_file) /* anonymous vma */
4674 inode = vma->vm_file->f_path.dentry->d_inode;
4675 mapping = vma->vm_file->f_mapping;
4676 if (pte_none(ptent))
4677 pgoff = linear_page_index(vma, addr);
4678 else /* pte_file(ptent) is true */
4679 pgoff = pte_to_pgoff(ptent);
4681 /* page is moved even if it's not RSS of this task(page-faulted). */
4682 if (!mapping_cap_swap_backed(mapping)) { /* normal file */
4683 page = find_get_page(mapping, pgoff);
4684 } else { /* shmem/tmpfs file. we should take account of swap too. */
4686 mem_cgroup_get_shmem_target(inode, pgoff, &page, &ent);
4687 if (do_swap_account)
4688 entry->val = ent.val;
4694 static int is_target_pte_for_mc(struct vm_area_struct *vma,
4695 unsigned long addr, pte_t ptent, union mc_target *target)
4697 struct page *page = NULL;
4698 struct page_cgroup *pc;
4700 swp_entry_t ent = { .val = 0 };
4702 if (pte_present(ptent))
4703 page = mc_handle_present_pte(vma, addr, ptent);
4704 else if (is_swap_pte(ptent))
4705 page = mc_handle_swap_pte(vma, addr, ptent, &ent);
4706 else if (pte_none(ptent) || pte_file(ptent))
4707 page = mc_handle_file_pte(vma, addr, ptent, &ent);
4709 if (!page && !ent.val)
4712 pc = lookup_page_cgroup(page);
4714 * Do only loose check w/o page_cgroup lock.
4715 * mem_cgroup_move_account() checks the pc is valid or not under
4718 if (PageCgroupUsed(pc) && pc->mem_cgroup == mc.from) {
4719 ret = MC_TARGET_PAGE;
4721 target->page = page;
4723 if (!ret || !target)
4726 /* There is a swap entry and a page doesn't exist or isn't charged */
4727 if (ent.val && !ret &&
4728 css_id(&mc.from->css) == lookup_swap_cgroup(ent)) {
4729 ret = MC_TARGET_SWAP;
4736 static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd,
4737 unsigned long addr, unsigned long end,
4738 struct mm_walk *walk)
4740 struct vm_area_struct *vma = walk->private;
4744 split_huge_page_pmd(walk->mm, pmd);
4746 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
4747 for (; addr != end; pte++, addr += PAGE_SIZE)
4748 if (is_target_pte_for_mc(vma, addr, *pte, NULL))
4749 mc.precharge++; /* increment precharge temporarily */
4750 pte_unmap_unlock(pte - 1, ptl);
4756 static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm)
4758 unsigned long precharge;
4759 struct vm_area_struct *vma;
4761 down_read(&mm->mmap_sem);
4762 for (vma = mm->mmap; vma; vma = vma->vm_next) {
4763 struct mm_walk mem_cgroup_count_precharge_walk = {
4764 .pmd_entry = mem_cgroup_count_precharge_pte_range,
4768 if (is_vm_hugetlb_page(vma))
4770 walk_page_range(vma->vm_start, vma->vm_end,
4771 &mem_cgroup_count_precharge_walk);
4773 up_read(&mm->mmap_sem);
4775 precharge = mc.precharge;
4781 static int mem_cgroup_precharge_mc(struct mm_struct *mm)
4783 unsigned long precharge = mem_cgroup_count_precharge(mm);
4785 VM_BUG_ON(mc.moving_task);
4786 mc.moving_task = current;
4787 return mem_cgroup_do_precharge(precharge);
4790 /* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */
4791 static void __mem_cgroup_clear_mc(void)
4793 struct mem_cgroup *from = mc.from;
4794 struct mem_cgroup *to = mc.to;
4796 /* we must uncharge all the leftover precharges from mc.to */
4798 __mem_cgroup_cancel_charge(mc.to, mc.precharge);
4802 * we didn't uncharge from mc.from at mem_cgroup_move_account(), so
4803 * we must uncharge here.
4805 if (mc.moved_charge) {
4806 __mem_cgroup_cancel_charge(mc.from, mc.moved_charge);
4807 mc.moved_charge = 0;
4809 /* we must fixup refcnts and charges */
4810 if (mc.moved_swap) {
4811 /* uncharge swap account from the old cgroup */
4812 if (!mem_cgroup_is_root(mc.from))
4813 res_counter_uncharge(&mc.from->memsw,
4814 PAGE_SIZE * mc.moved_swap);
4815 __mem_cgroup_put(mc.from, mc.moved_swap);
4817 if (!mem_cgroup_is_root(mc.to)) {
4819 * we charged both to->res and to->memsw, so we should
4822 res_counter_uncharge(&mc.to->res,
4823 PAGE_SIZE * mc.moved_swap);
4825 /* we've already done mem_cgroup_get(mc.to) */
4828 memcg_oom_recover(from);
4829 memcg_oom_recover(to);
4830 wake_up_all(&mc.waitq);
4833 static void mem_cgroup_clear_mc(void)
4835 struct mem_cgroup *from = mc.from;
4838 * we must clear moving_task before waking up waiters at the end of
4841 mc.moving_task = NULL;
4842 __mem_cgroup_clear_mc();
4843 spin_lock(&mc.lock);
4846 spin_unlock(&mc.lock);
4847 mem_cgroup_end_move(from);
4850 static int mem_cgroup_can_attach(struct cgroup_subsys *ss,
4851 struct cgroup *cgroup,
4852 struct task_struct *p,
4856 struct mem_cgroup *mem = mem_cgroup_from_cont(cgroup);
4858 if (mem->move_charge_at_immigrate) {
4859 struct mm_struct *mm;
4860 struct mem_cgroup *from = mem_cgroup_from_task(p);
4862 VM_BUG_ON(from == mem);
4864 mm = get_task_mm(p);
4867 /* We move charges only when we move a owner of the mm */
4868 if (mm->owner == p) {
4871 VM_BUG_ON(mc.precharge);
4872 VM_BUG_ON(mc.moved_charge);
4873 VM_BUG_ON(mc.moved_swap);
4874 mem_cgroup_start_move(from);
4875 spin_lock(&mc.lock);
4878 spin_unlock(&mc.lock);
4879 /* We set mc.moving_task later */
4881 ret = mem_cgroup_precharge_mc(mm);
4883 mem_cgroup_clear_mc();
4890 static void mem_cgroup_cancel_attach(struct cgroup_subsys *ss,
4891 struct cgroup *cgroup,
4892 struct task_struct *p,
4895 mem_cgroup_clear_mc();
4898 static int mem_cgroup_move_charge_pte_range(pmd_t *pmd,
4899 unsigned long addr, unsigned long end,
4900 struct mm_walk *walk)
4903 struct vm_area_struct *vma = walk->private;
4907 split_huge_page_pmd(walk->mm, pmd);
4909 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
4910 for (; addr != end; addr += PAGE_SIZE) {
4911 pte_t ptent = *(pte++);
4912 union mc_target target;
4915 struct page_cgroup *pc;
4921 type = is_target_pte_for_mc(vma, addr, ptent, &target);
4923 case MC_TARGET_PAGE:
4925 if (isolate_lru_page(page))
4927 pc = lookup_page_cgroup(page);
4928 if (!mem_cgroup_move_account(pc,
4929 mc.from, mc.to, false, PAGE_SIZE)) {
4931 /* we uncharge from mc.from later. */
4934 putback_lru_page(page);
4935 put: /* is_target_pte_for_mc() gets the page */
4938 case MC_TARGET_SWAP:
4940 if (!mem_cgroup_move_swap_account(ent,
4941 mc.from, mc.to, false)) {
4943 /* we fixup refcnts and charges later. */
4951 pte_unmap_unlock(pte - 1, ptl);
4956 * We have consumed all precharges we got in can_attach().
4957 * We try charge one by one, but don't do any additional
4958 * charges to mc.to if we have failed in charge once in attach()
4961 ret = mem_cgroup_do_precharge(1);
4969 static void mem_cgroup_move_charge(struct mm_struct *mm)
4971 struct vm_area_struct *vma;
4973 lru_add_drain_all();
4975 if (unlikely(!down_read_trylock(&mm->mmap_sem))) {
4977 * Someone who are holding the mmap_sem might be waiting in
4978 * waitq. So we cancel all extra charges, wake up all waiters,
4979 * and retry. Because we cancel precharges, we might not be able
4980 * to move enough charges, but moving charge is a best-effort
4981 * feature anyway, so it wouldn't be a big problem.
4983 __mem_cgroup_clear_mc();
4987 for (vma = mm->mmap; vma; vma = vma->vm_next) {
4989 struct mm_walk mem_cgroup_move_charge_walk = {
4990 .pmd_entry = mem_cgroup_move_charge_pte_range,
4994 if (is_vm_hugetlb_page(vma))
4996 ret = walk_page_range(vma->vm_start, vma->vm_end,
4997 &mem_cgroup_move_charge_walk);
5000 * means we have consumed all precharges and failed in
5001 * doing additional charge. Just abandon here.
5005 up_read(&mm->mmap_sem);
5008 static void mem_cgroup_move_task(struct cgroup_subsys *ss,
5009 struct cgroup *cont,
5010 struct cgroup *old_cont,
5011 struct task_struct *p,
5014 struct mm_struct *mm;
5017 /* no need to move charge */
5020 mm = get_task_mm(p);
5022 mem_cgroup_move_charge(mm);
5025 mem_cgroup_clear_mc();
5027 #else /* !CONFIG_MMU */
5028 static int mem_cgroup_can_attach(struct cgroup_subsys *ss,
5029 struct cgroup *cgroup,
5030 struct task_struct *p,
5035 static void mem_cgroup_cancel_attach(struct cgroup_subsys *ss,
5036 struct cgroup *cgroup,
5037 struct task_struct *p,
5041 static void mem_cgroup_move_task(struct cgroup_subsys *ss,
5042 struct cgroup *cont,
5043 struct cgroup *old_cont,
5044 struct task_struct *p,
5050 struct cgroup_subsys mem_cgroup_subsys = {
5052 .subsys_id = mem_cgroup_subsys_id,
5053 .create = mem_cgroup_create,
5054 .pre_destroy = mem_cgroup_pre_destroy,
5055 .destroy = mem_cgroup_destroy,
5056 .populate = mem_cgroup_populate,
5057 .can_attach = mem_cgroup_can_attach,
5058 .cancel_attach = mem_cgroup_cancel_attach,
5059 .attach = mem_cgroup_move_task,
5064 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
5065 static int __init enable_swap_account(char *s)
5067 /* consider enabled if no parameter or 1 is given */
5068 if (!(*s) || !strcmp(s, "=1"))
5069 really_do_swap_account = 1;
5070 else if (!strcmp(s, "=0"))
5071 really_do_swap_account = 0;
5074 __setup("swapaccount", enable_swap_account);
5076 static int __init disable_swap_account(char *s)
5078 printk_once("noswapaccount is deprecated and will be removed in 2.6.40. Use swapaccount=0 instead\n");
5079 enable_swap_account("=0");
5082 __setup("noswapaccount", disable_swap_account);