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;
64 static int really_do_swap_account __initdata = 1; /* for remember boot option*/
66 #define do_swap_account (0)
70 * Per memcg event counter is incremented at every pagein/pageout. This counter
71 * is used for trigger some periodic events. This is straightforward and better
72 * than using jiffies etc. to handle periodic memcg event.
74 * These values will be used as !((event) & ((1 <<(thresh)) - 1))
76 #define THRESHOLDS_EVENTS_THRESH (7) /* once in 128 */
77 #define SOFTLIMIT_EVENTS_THRESH (10) /* once in 1024 */
80 * Statistics for memory cgroup.
82 enum mem_cgroup_stat_index {
84 * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss.
86 MEM_CGROUP_STAT_CACHE, /* # of pages charged as cache */
87 MEM_CGROUP_STAT_RSS, /* # of pages charged as anon rss */
88 MEM_CGROUP_STAT_FILE_MAPPED, /* # of pages charged as file rss */
89 MEM_CGROUP_STAT_PGPGIN_COUNT, /* # of pages paged in */
90 MEM_CGROUP_STAT_PGPGOUT_COUNT, /* # of pages paged out */
91 MEM_CGROUP_STAT_SWAPOUT, /* # of pages, swapped out */
92 MEM_CGROUP_STAT_DATA, /* end of data requires synchronization */
93 /* incremented at every pagein/pageout */
94 MEM_CGROUP_EVENTS = MEM_CGROUP_STAT_DATA,
95 MEM_CGROUP_ON_MOVE, /* someone is moving account between groups */
97 MEM_CGROUP_STAT_NSTATS,
100 struct mem_cgroup_stat_cpu {
101 s64 count[MEM_CGROUP_STAT_NSTATS];
105 * per-zone information in memory controller.
107 struct mem_cgroup_per_zone {
109 * spin_lock to protect the per cgroup LRU
111 struct list_head lists[NR_LRU_LISTS];
112 unsigned long count[NR_LRU_LISTS];
114 struct zone_reclaim_stat reclaim_stat;
115 struct rb_node tree_node; /* RB tree node */
116 unsigned long long usage_in_excess;/* Set to the value by which */
117 /* the soft limit is exceeded*/
119 struct mem_cgroup *mem; /* Back pointer, we cannot */
120 /* use container_of */
122 /* Macro for accessing counter */
123 #define MEM_CGROUP_ZSTAT(mz, idx) ((mz)->count[(idx)])
125 struct mem_cgroup_per_node {
126 struct mem_cgroup_per_zone zoneinfo[MAX_NR_ZONES];
129 struct mem_cgroup_lru_info {
130 struct mem_cgroup_per_node *nodeinfo[MAX_NUMNODES];
134 * Cgroups above their limits are maintained in a RB-Tree, independent of
135 * their hierarchy representation
138 struct mem_cgroup_tree_per_zone {
139 struct rb_root rb_root;
143 struct mem_cgroup_tree_per_node {
144 struct mem_cgroup_tree_per_zone rb_tree_per_zone[MAX_NR_ZONES];
147 struct mem_cgroup_tree {
148 struct mem_cgroup_tree_per_node *rb_tree_per_node[MAX_NUMNODES];
151 static struct mem_cgroup_tree soft_limit_tree __read_mostly;
153 struct mem_cgroup_threshold {
154 struct eventfd_ctx *eventfd;
159 struct mem_cgroup_threshold_ary {
160 /* An array index points to threshold just below usage. */
161 int current_threshold;
162 /* Size of entries[] */
164 /* Array of thresholds */
165 struct mem_cgroup_threshold entries[0];
168 struct mem_cgroup_thresholds {
169 /* Primary thresholds array */
170 struct mem_cgroup_threshold_ary *primary;
172 * Spare threshold array.
173 * This is needed to make mem_cgroup_unregister_event() "never fail".
174 * It must be able to store at least primary->size - 1 entries.
176 struct mem_cgroup_threshold_ary *spare;
180 struct mem_cgroup_eventfd_list {
181 struct list_head list;
182 struct eventfd_ctx *eventfd;
185 static void mem_cgroup_threshold(struct mem_cgroup *mem);
186 static void mem_cgroup_oom_notify(struct mem_cgroup *mem);
189 * The memory controller data structure. The memory controller controls both
190 * page cache and RSS per cgroup. We would eventually like to provide
191 * statistics based on the statistics developed by Rik Van Riel for clock-pro,
192 * to help the administrator determine what knobs to tune.
194 * TODO: Add a water mark for the memory controller. Reclaim will begin when
195 * we hit the water mark. May be even add a low water mark, such that
196 * no reclaim occurs from a cgroup at it's low water mark, this is
197 * a feature that will be implemented much later in the future.
200 struct cgroup_subsys_state css;
202 * the counter to account for memory usage
204 struct res_counter res;
206 * the counter to account for mem+swap usage.
208 struct res_counter memsw;
210 * Per cgroup active and inactive list, similar to the
211 * per zone LRU lists.
213 struct mem_cgroup_lru_info info;
216 protect against reclaim related member.
218 spinlock_t reclaim_param_lock;
221 * While reclaiming in a hierarchy, we cache the last child we
224 int last_scanned_child;
226 * Should the accounting and control be hierarchical, per subtree?
232 unsigned int swappiness;
233 /* OOM-Killer disable */
234 int oom_kill_disable;
236 /* set when res.limit == memsw.limit */
237 bool memsw_is_minimum;
239 /* protect arrays of thresholds */
240 struct mutex thresholds_lock;
242 /* thresholds for memory usage. RCU-protected */
243 struct mem_cgroup_thresholds thresholds;
245 /* thresholds for mem+swap usage. RCU-protected */
246 struct mem_cgroup_thresholds memsw_thresholds;
248 /* For oom notifier event fd */
249 struct list_head oom_notify;
252 * Should we move charges of a task when a task is moved into this
253 * mem_cgroup ? And what type of charges should we move ?
255 unsigned long move_charge_at_immigrate;
259 struct mem_cgroup_stat_cpu *stat;
261 * used when a cpu is offlined or other synchronizations
262 * See mem_cgroup_read_stat().
264 struct mem_cgroup_stat_cpu nocpu_base;
265 spinlock_t pcp_counter_lock;
268 /* Stuffs for move charges at task migration. */
270 * Types of charges to be moved. "move_charge_at_immitgrate" is treated as a
271 * left-shifted bitmap of these types.
274 MOVE_CHARGE_TYPE_ANON, /* private anonymous page and swap of it */
275 MOVE_CHARGE_TYPE_FILE, /* file page(including tmpfs) and swap of it */
279 /* "mc" and its members are protected by cgroup_mutex */
280 static struct move_charge_struct {
281 spinlock_t lock; /* for from, to, moving_task */
282 struct mem_cgroup *from;
283 struct mem_cgroup *to;
284 unsigned long precharge;
285 unsigned long moved_charge;
286 unsigned long moved_swap;
287 struct task_struct *moving_task; /* a task moving charges */
288 wait_queue_head_t waitq; /* a waitq for other context */
290 .lock = __SPIN_LOCK_UNLOCKED(mc.lock),
291 .waitq = __WAIT_QUEUE_HEAD_INITIALIZER(mc.waitq),
294 static bool move_anon(void)
296 return test_bit(MOVE_CHARGE_TYPE_ANON,
297 &mc.to->move_charge_at_immigrate);
300 static bool move_file(void)
302 return test_bit(MOVE_CHARGE_TYPE_FILE,
303 &mc.to->move_charge_at_immigrate);
307 * Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft
308 * limit reclaim to prevent infinite loops, if they ever occur.
310 #define MEM_CGROUP_MAX_RECLAIM_LOOPS (100)
311 #define MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS (2)
314 MEM_CGROUP_CHARGE_TYPE_CACHE = 0,
315 MEM_CGROUP_CHARGE_TYPE_MAPPED,
316 MEM_CGROUP_CHARGE_TYPE_SHMEM, /* used by page migration of shmem */
317 MEM_CGROUP_CHARGE_TYPE_FORCE, /* used by force_empty */
318 MEM_CGROUP_CHARGE_TYPE_SWAPOUT, /* for accounting swapcache */
319 MEM_CGROUP_CHARGE_TYPE_DROP, /* a page was unused swap cache */
323 /* only for here (for easy reading.) */
324 #define PCGF_CACHE (1UL << PCG_CACHE)
325 #define PCGF_USED (1UL << PCG_USED)
326 #define PCGF_LOCK (1UL << PCG_LOCK)
327 /* Not used, but added here for completeness */
328 #define PCGF_ACCT (1UL << PCG_ACCT)
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 inline unsigned long mem_cgroup_get_excess(struct mem_cgroup *mem)
502 return res_counter_soft_limit_excess(&mem->res) >> PAGE_SHIFT;
505 static struct mem_cgroup_per_zone *
506 __mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
508 struct rb_node *rightmost = NULL;
509 struct mem_cgroup_per_zone *mz;
513 rightmost = rb_last(&mctz->rb_root);
515 goto done; /* Nothing to reclaim from */
517 mz = rb_entry(rightmost, struct mem_cgroup_per_zone, tree_node);
519 * Remove the node now but someone else can add it back,
520 * we will to add it back at the end of reclaim to its correct
521 * position in the tree.
523 __mem_cgroup_remove_exceeded(mz->mem, mz, mctz);
524 if (!res_counter_soft_limit_excess(&mz->mem->res) ||
525 !css_tryget(&mz->mem->css))
531 static struct mem_cgroup_per_zone *
532 mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
534 struct mem_cgroup_per_zone *mz;
536 spin_lock(&mctz->lock);
537 mz = __mem_cgroup_largest_soft_limit_node(mctz);
538 spin_unlock(&mctz->lock);
543 * Implementation Note: reading percpu statistics for memcg.
545 * Both of vmstat[] and percpu_counter has threshold and do periodic
546 * synchronization to implement "quick" read. There are trade-off between
547 * reading cost and precision of value. Then, we may have a chance to implement
548 * a periodic synchronizion of counter in memcg's counter.
550 * But this _read() function is used for user interface now. The user accounts
551 * memory usage by memory cgroup and he _always_ requires exact value because
552 * he accounts memory. Even if we provide quick-and-fuzzy read, we always
553 * have to visit all online cpus and make sum. So, for now, unnecessary
554 * synchronization is not implemented. (just implemented for cpu hotplug)
556 * If there are kernel internal actions which can make use of some not-exact
557 * value, and reading all cpu value can be performance bottleneck in some
558 * common workload, threashold and synchonization as vmstat[] should be
561 static s64 mem_cgroup_read_stat(struct mem_cgroup *mem,
562 enum mem_cgroup_stat_index idx)
568 for_each_online_cpu(cpu)
569 val += per_cpu(mem->stat->count[idx], cpu);
570 #ifdef CONFIG_HOTPLUG_CPU
571 spin_lock(&mem->pcp_counter_lock);
572 val += mem->nocpu_base.count[idx];
573 spin_unlock(&mem->pcp_counter_lock);
579 static s64 mem_cgroup_local_usage(struct mem_cgroup *mem)
583 ret = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_RSS);
584 ret += mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_CACHE);
588 static void mem_cgroup_swap_statistics(struct mem_cgroup *mem,
591 int val = (charge) ? 1 : -1;
592 this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_SWAPOUT], val);
595 static void mem_cgroup_charge_statistics(struct mem_cgroup *mem,
596 struct page_cgroup *pc,
599 int val = (charge) ? 1 : -1;
603 if (PageCgroupCache(pc))
604 __this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_CACHE], val);
606 __this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_RSS], val);
609 __this_cpu_inc(mem->stat->count[MEM_CGROUP_STAT_PGPGIN_COUNT]);
611 __this_cpu_inc(mem->stat->count[MEM_CGROUP_STAT_PGPGOUT_COUNT]);
612 __this_cpu_inc(mem->stat->count[MEM_CGROUP_EVENTS]);
617 static unsigned long mem_cgroup_get_local_zonestat(struct mem_cgroup *mem,
621 struct mem_cgroup_per_zone *mz;
624 for_each_online_node(nid)
625 for (zid = 0; zid < MAX_NR_ZONES; zid++) {
626 mz = mem_cgroup_zoneinfo(mem, nid, zid);
627 total += MEM_CGROUP_ZSTAT(mz, idx);
632 static bool __memcg_event_check(struct mem_cgroup *mem, int event_mask_shift)
636 val = this_cpu_read(mem->stat->count[MEM_CGROUP_EVENTS]);
638 return !(val & ((1 << event_mask_shift) - 1));
642 * Check events in order.
645 static void memcg_check_events(struct mem_cgroup *mem, struct page *page)
647 /* threshold event is triggered in finer grain than soft limit */
648 if (unlikely(__memcg_event_check(mem, THRESHOLDS_EVENTS_THRESH))) {
649 mem_cgroup_threshold(mem);
650 if (unlikely(__memcg_event_check(mem, SOFTLIMIT_EVENTS_THRESH)))
651 mem_cgroup_update_tree(mem, page);
655 static struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont)
657 return container_of(cgroup_subsys_state(cont,
658 mem_cgroup_subsys_id), struct mem_cgroup,
662 struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
665 * mm_update_next_owner() may clear mm->owner to NULL
666 * if it races with swapoff, page migration, etc.
667 * So this can be called with p == NULL.
672 return container_of(task_subsys_state(p, mem_cgroup_subsys_id),
673 struct mem_cgroup, css);
676 static struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm)
678 struct mem_cgroup *mem = NULL;
683 * Because we have no locks, mm->owner's may be being moved to other
684 * cgroup. We use css_tryget() here even if this looks
685 * pessimistic (rather than adding locks here).
689 mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
692 } while (!css_tryget(&mem->css));
697 /* The caller has to guarantee "mem" exists before calling this */
698 static struct mem_cgroup *mem_cgroup_start_loop(struct mem_cgroup *mem)
700 struct cgroup_subsys_state *css;
703 if (!mem) /* ROOT cgroup has the smallest ID */
704 return root_mem_cgroup; /*css_put/get against root is ignored*/
705 if (!mem->use_hierarchy) {
706 if (css_tryget(&mem->css))
712 * searching a memory cgroup which has the smallest ID under given
713 * ROOT cgroup. (ID >= 1)
715 css = css_get_next(&mem_cgroup_subsys, 1, &mem->css, &found);
716 if (css && css_tryget(css))
717 mem = container_of(css, struct mem_cgroup, css);
724 static struct mem_cgroup *mem_cgroup_get_next(struct mem_cgroup *iter,
725 struct mem_cgroup *root,
728 int nextid = css_id(&iter->css) + 1;
731 struct cgroup_subsys_state *css;
733 hierarchy_used = iter->use_hierarchy;
736 /* If no ROOT, walk all, ignore hierarchy */
737 if (!cond || (root && !hierarchy_used))
741 root = root_mem_cgroup;
747 css = css_get_next(&mem_cgroup_subsys, nextid,
749 if (css && css_tryget(css))
750 iter = container_of(css, struct mem_cgroup, css);
752 /* If css is NULL, no more cgroups will be found */
754 } while (css && !iter);
759 * for_eacn_mem_cgroup_tree() for visiting all cgroup under tree. Please
760 * be careful that "break" loop is not allowed. We have reference count.
761 * Instead of that modify "cond" to be false and "continue" to exit the loop.
763 #define for_each_mem_cgroup_tree_cond(iter, root, cond) \
764 for (iter = mem_cgroup_start_loop(root);\
766 iter = mem_cgroup_get_next(iter, root, cond))
768 #define for_each_mem_cgroup_tree(iter, root) \
769 for_each_mem_cgroup_tree_cond(iter, root, true)
771 #define for_each_mem_cgroup_all(iter) \
772 for_each_mem_cgroup_tree_cond(iter, NULL, true)
775 static inline bool mem_cgroup_is_root(struct mem_cgroup *mem)
777 return (mem == root_mem_cgroup);
781 * Following LRU functions are allowed to be used without PCG_LOCK.
782 * Operations are called by routine of global LRU independently from memcg.
783 * What we have to take care of here is validness of pc->mem_cgroup.
785 * Changes to pc->mem_cgroup happens when
788 * In typical case, "charge" is done before add-to-lru. Exception is SwapCache.
789 * It is added to LRU before charge.
790 * If PCG_USED bit is not set, page_cgroup is not added to this private LRU.
791 * When moving account, the page is not on LRU. It's isolated.
794 void mem_cgroup_del_lru_list(struct page *page, enum lru_list lru)
796 struct page_cgroup *pc;
797 struct mem_cgroup_per_zone *mz;
799 if (mem_cgroup_disabled())
801 pc = lookup_page_cgroup(page);
802 /* can happen while we handle swapcache. */
803 if (!TestClearPageCgroupAcctLRU(pc))
805 VM_BUG_ON(!pc->mem_cgroup);
807 * We don't check PCG_USED bit. It's cleared when the "page" is finally
808 * removed from global LRU.
810 mz = page_cgroup_zoneinfo(pc);
811 MEM_CGROUP_ZSTAT(mz, lru) -= 1;
812 if (mem_cgroup_is_root(pc->mem_cgroup))
814 VM_BUG_ON(list_empty(&pc->lru));
815 list_del_init(&pc->lru);
819 void mem_cgroup_del_lru(struct page *page)
821 mem_cgroup_del_lru_list(page, page_lru(page));
824 void mem_cgroup_rotate_lru_list(struct page *page, enum lru_list lru)
826 struct mem_cgroup_per_zone *mz;
827 struct page_cgroup *pc;
829 if (mem_cgroup_disabled())
832 pc = lookup_page_cgroup(page);
834 * Used bit is set without atomic ops but after smp_wmb().
835 * For making pc->mem_cgroup visible, insert smp_rmb() here.
838 /* unused or root page is not rotated. */
839 if (!PageCgroupUsed(pc) || mem_cgroup_is_root(pc->mem_cgroup))
841 mz = page_cgroup_zoneinfo(pc);
842 list_move(&pc->lru, &mz->lists[lru]);
845 void mem_cgroup_add_lru_list(struct page *page, enum lru_list lru)
847 struct page_cgroup *pc;
848 struct mem_cgroup_per_zone *mz;
850 if (mem_cgroup_disabled())
852 pc = lookup_page_cgroup(page);
853 VM_BUG_ON(PageCgroupAcctLRU(pc));
855 * Used bit is set without atomic ops but after smp_wmb().
856 * For making pc->mem_cgroup visible, insert smp_rmb() here.
859 if (!PageCgroupUsed(pc))
862 mz = page_cgroup_zoneinfo(pc);
863 MEM_CGROUP_ZSTAT(mz, lru) += 1;
864 SetPageCgroupAcctLRU(pc);
865 if (mem_cgroup_is_root(pc->mem_cgroup))
867 list_add(&pc->lru, &mz->lists[lru]);
871 * At handling SwapCache, pc->mem_cgroup may be changed while it's linked to
872 * lru because the page may.be reused after it's fully uncharged (because of
873 * SwapCache behavior).To handle that, unlink page_cgroup from LRU when charge
874 * it again. This function is only used to charge SwapCache. It's done under
875 * lock_page and expected that zone->lru_lock is never held.
877 static void mem_cgroup_lru_del_before_commit_swapcache(struct page *page)
880 struct zone *zone = page_zone(page);
881 struct page_cgroup *pc = lookup_page_cgroup(page);
883 spin_lock_irqsave(&zone->lru_lock, flags);
885 * Forget old LRU when this page_cgroup is *not* used. This Used bit
886 * is guarded by lock_page() because the page is SwapCache.
888 if (!PageCgroupUsed(pc))
889 mem_cgroup_del_lru_list(page, page_lru(page));
890 spin_unlock_irqrestore(&zone->lru_lock, flags);
893 static void mem_cgroup_lru_add_after_commit_swapcache(struct page *page)
896 struct zone *zone = page_zone(page);
897 struct page_cgroup *pc = lookup_page_cgroup(page);
899 spin_lock_irqsave(&zone->lru_lock, flags);
900 /* link when the page is linked to LRU but page_cgroup isn't */
901 if (PageLRU(page) && !PageCgroupAcctLRU(pc))
902 mem_cgroup_add_lru_list(page, page_lru(page));
903 spin_unlock_irqrestore(&zone->lru_lock, flags);
907 void mem_cgroup_move_lists(struct page *page,
908 enum lru_list from, enum lru_list to)
910 if (mem_cgroup_disabled())
912 mem_cgroup_del_lru_list(page, from);
913 mem_cgroup_add_lru_list(page, to);
916 int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem)
919 struct mem_cgroup *curr = NULL;
920 struct task_struct *p;
922 p = find_lock_task_mm(task);
925 curr = try_get_mem_cgroup_from_mm(p->mm);
930 * We should check use_hierarchy of "mem" not "curr". Because checking
931 * use_hierarchy of "curr" here make this function true if hierarchy is
932 * enabled in "curr" and "curr" is a child of "mem" in *cgroup*
933 * hierarchy(even if use_hierarchy is disabled in "mem").
935 if (mem->use_hierarchy)
936 ret = css_is_ancestor(&curr->css, &mem->css);
943 static int calc_inactive_ratio(struct mem_cgroup *memcg, unsigned long *present_pages)
945 unsigned long active;
946 unsigned long inactive;
948 unsigned long inactive_ratio;
950 inactive = mem_cgroup_get_local_zonestat(memcg, LRU_INACTIVE_ANON);
951 active = mem_cgroup_get_local_zonestat(memcg, LRU_ACTIVE_ANON);
953 gb = (inactive + active) >> (30 - PAGE_SHIFT);
955 inactive_ratio = int_sqrt(10 * gb);
960 present_pages[0] = inactive;
961 present_pages[1] = active;
964 return inactive_ratio;
967 int mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg)
969 unsigned long active;
970 unsigned long inactive;
971 unsigned long present_pages[2];
972 unsigned long inactive_ratio;
974 inactive_ratio = calc_inactive_ratio(memcg, present_pages);
976 inactive = present_pages[0];
977 active = present_pages[1];
979 if (inactive * inactive_ratio < active)
985 int mem_cgroup_inactive_file_is_low(struct mem_cgroup *memcg)
987 unsigned long active;
988 unsigned long inactive;
990 inactive = mem_cgroup_get_local_zonestat(memcg, LRU_INACTIVE_FILE);
991 active = mem_cgroup_get_local_zonestat(memcg, LRU_ACTIVE_FILE);
993 return (active > inactive);
996 unsigned long mem_cgroup_zone_nr_pages(struct mem_cgroup *memcg,
1000 int nid = zone_to_nid(zone);
1001 int zid = zone_idx(zone);
1002 struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid);
1004 return MEM_CGROUP_ZSTAT(mz, lru);
1007 struct zone_reclaim_stat *mem_cgroup_get_reclaim_stat(struct mem_cgroup *memcg,
1010 int nid = zone_to_nid(zone);
1011 int zid = zone_idx(zone);
1012 struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid);
1014 return &mz->reclaim_stat;
1017 struct zone_reclaim_stat *
1018 mem_cgroup_get_reclaim_stat_from_page(struct page *page)
1020 struct page_cgroup *pc;
1021 struct mem_cgroup_per_zone *mz;
1023 if (mem_cgroup_disabled())
1026 pc = lookup_page_cgroup(page);
1028 * Used bit is set without atomic ops but after smp_wmb().
1029 * For making pc->mem_cgroup visible, insert smp_rmb() here.
1032 if (!PageCgroupUsed(pc))
1035 mz = page_cgroup_zoneinfo(pc);
1039 return &mz->reclaim_stat;
1042 unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
1043 struct list_head *dst,
1044 unsigned long *scanned, int order,
1045 int mode, struct zone *z,
1046 struct mem_cgroup *mem_cont,
1047 int active, int file)
1049 unsigned long nr_taken = 0;
1053 struct list_head *src;
1054 struct page_cgroup *pc, *tmp;
1055 int nid = zone_to_nid(z);
1056 int zid = zone_idx(z);
1057 struct mem_cgroup_per_zone *mz;
1058 int lru = LRU_FILE * file + active;
1062 mz = mem_cgroup_zoneinfo(mem_cont, nid, zid);
1063 src = &mz->lists[lru];
1066 list_for_each_entry_safe_reverse(pc, tmp, src, lru) {
1067 if (scan >= nr_to_scan)
1071 if (unlikely(!PageCgroupUsed(pc)))
1073 if (unlikely(!PageLRU(page)))
1077 ret = __isolate_lru_page(page, mode, file);
1080 list_move(&page->lru, dst);
1081 mem_cgroup_del_lru(page);
1085 /* we don't affect global LRU but rotate in our LRU */
1086 mem_cgroup_rotate_lru_list(page, page_lru(page));
1095 trace_mm_vmscan_memcg_isolate(0, nr_to_scan, scan, nr_taken,
1101 #define mem_cgroup_from_res_counter(counter, member) \
1102 container_of(counter, struct mem_cgroup, member)
1104 static bool mem_cgroup_check_under_limit(struct mem_cgroup *mem)
1106 if (do_swap_account) {
1107 if (res_counter_check_under_limit(&mem->res) &&
1108 res_counter_check_under_limit(&mem->memsw))
1111 if (res_counter_check_under_limit(&mem->res))
1116 static unsigned int get_swappiness(struct mem_cgroup *memcg)
1118 struct cgroup *cgrp = memcg->css.cgroup;
1119 unsigned int swappiness;
1122 if (cgrp->parent == NULL)
1123 return vm_swappiness;
1125 spin_lock(&memcg->reclaim_param_lock);
1126 swappiness = memcg->swappiness;
1127 spin_unlock(&memcg->reclaim_param_lock);
1132 static void mem_cgroup_start_move(struct mem_cgroup *mem)
1135 /* Because this is for moving account, reuse mc.lock */
1136 spin_lock(&mc.lock);
1137 for_each_possible_cpu(cpu)
1138 per_cpu(mem->stat->count[MEM_CGROUP_ON_MOVE], cpu) += 1;
1139 spin_unlock(&mc.lock);
1144 static void mem_cgroup_end_move(struct mem_cgroup *mem)
1150 spin_lock(&mc.lock);
1151 for_each_possible_cpu(cpu)
1152 per_cpu(mem->stat->count[MEM_CGROUP_ON_MOVE], cpu) -= 1;
1153 spin_unlock(&mc.lock);
1156 * 2 routines for checking "mem" is under move_account() or not.
1158 * mem_cgroup_stealed() - checking a cgroup is mc.from or not. This is used
1159 * for avoiding race in accounting. If true,
1160 * pc->mem_cgroup may be overwritten.
1162 * mem_cgroup_under_move() - checking a cgroup is mc.from or mc.to or
1163 * under hierarchy of moving cgroups. This is for
1164 * waiting at hith-memory prressure caused by "move".
1167 static bool mem_cgroup_stealed(struct mem_cgroup *mem)
1169 VM_BUG_ON(!rcu_read_lock_held());
1170 return this_cpu_read(mem->stat->count[MEM_CGROUP_ON_MOVE]) > 0;
1173 static bool mem_cgroup_under_move(struct mem_cgroup *mem)
1175 struct mem_cgroup *from;
1176 struct mem_cgroup *to;
1179 * Unlike task_move routines, we access mc.to, mc.from not under
1180 * mutual exclusion by cgroup_mutex. Here, we take spinlock instead.
1182 spin_lock(&mc.lock);
1187 if (from == mem || to == mem
1188 || (mem->use_hierarchy && css_is_ancestor(&from->css, &mem->css))
1189 || (mem->use_hierarchy && css_is_ancestor(&to->css, &mem->css)))
1192 spin_unlock(&mc.lock);
1196 static bool mem_cgroup_wait_acct_move(struct mem_cgroup *mem)
1198 if (mc.moving_task && current != mc.moving_task) {
1199 if (mem_cgroup_under_move(mem)) {
1201 prepare_to_wait(&mc.waitq, &wait, TASK_INTERRUPTIBLE);
1202 /* moving charge context might have finished. */
1205 finish_wait(&mc.waitq, &wait);
1213 * mem_cgroup_print_oom_info: Called from OOM with tasklist_lock held in read mode.
1214 * @memcg: The memory cgroup that went over limit
1215 * @p: Task that is going to be killed
1217 * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is
1220 void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
1222 struct cgroup *task_cgrp;
1223 struct cgroup *mem_cgrp;
1225 * Need a buffer in BSS, can't rely on allocations. The code relies
1226 * on the assumption that OOM is serialized for memory controller.
1227 * If this assumption is broken, revisit this code.
1229 static char memcg_name[PATH_MAX];
1238 mem_cgrp = memcg->css.cgroup;
1239 task_cgrp = task_cgroup(p, mem_cgroup_subsys_id);
1241 ret = cgroup_path(task_cgrp, memcg_name, PATH_MAX);
1244 * Unfortunately, we are unable to convert to a useful name
1245 * But we'll still print out the usage information
1252 printk(KERN_INFO "Task in %s killed", memcg_name);
1255 ret = cgroup_path(mem_cgrp, memcg_name, PATH_MAX);
1263 * Continues from above, so we don't need an KERN_ level
1265 printk(KERN_CONT " as a result of limit of %s\n", memcg_name);
1268 printk(KERN_INFO "memory: usage %llukB, limit %llukB, failcnt %llu\n",
1269 res_counter_read_u64(&memcg->res, RES_USAGE) >> 10,
1270 res_counter_read_u64(&memcg->res, RES_LIMIT) >> 10,
1271 res_counter_read_u64(&memcg->res, RES_FAILCNT));
1272 printk(KERN_INFO "memory+swap: usage %llukB, limit %llukB, "
1274 res_counter_read_u64(&memcg->memsw, RES_USAGE) >> 10,
1275 res_counter_read_u64(&memcg->memsw, RES_LIMIT) >> 10,
1276 res_counter_read_u64(&memcg->memsw, RES_FAILCNT));
1280 * This function returns the number of memcg under hierarchy tree. Returns
1281 * 1(self count) if no children.
1283 static int mem_cgroup_count_children(struct mem_cgroup *mem)
1286 struct mem_cgroup *iter;
1288 for_each_mem_cgroup_tree(iter, mem)
1294 * Return the memory (and swap, if configured) limit for a memcg.
1296 u64 mem_cgroup_get_limit(struct mem_cgroup *memcg)
1301 limit = res_counter_read_u64(&memcg->res, RES_LIMIT) +
1303 memsw = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
1305 * If memsw is finite and limits the amount of swap space available
1306 * to this memcg, return that limit.
1308 return min(limit, memsw);
1312 * Visit the first child (need not be the first child as per the ordering
1313 * of the cgroup list, since we track last_scanned_child) of @mem and use
1314 * that to reclaim free pages from.
1316 static struct mem_cgroup *
1317 mem_cgroup_select_victim(struct mem_cgroup *root_mem)
1319 struct mem_cgroup *ret = NULL;
1320 struct cgroup_subsys_state *css;
1323 if (!root_mem->use_hierarchy) {
1324 css_get(&root_mem->css);
1330 nextid = root_mem->last_scanned_child + 1;
1331 css = css_get_next(&mem_cgroup_subsys, nextid, &root_mem->css,
1333 if (css && css_tryget(css))
1334 ret = container_of(css, struct mem_cgroup, css);
1337 /* Updates scanning parameter */
1338 spin_lock(&root_mem->reclaim_param_lock);
1340 /* this means start scan from ID:1 */
1341 root_mem->last_scanned_child = 0;
1343 root_mem->last_scanned_child = found;
1344 spin_unlock(&root_mem->reclaim_param_lock);
1351 * Scan the hierarchy if needed to reclaim memory. We remember the last child
1352 * we reclaimed from, so that we don't end up penalizing one child extensively
1353 * based on its position in the children list.
1355 * root_mem is the original ancestor that we've been reclaim from.
1357 * We give up and return to the caller when we visit root_mem twice.
1358 * (other groups can be removed while we're walking....)
1360 * If shrink==true, for avoiding to free too much, this returns immedieately.
1362 static int mem_cgroup_hierarchical_reclaim(struct mem_cgroup *root_mem,
1365 unsigned long reclaim_options)
1367 struct mem_cgroup *victim;
1370 bool noswap = reclaim_options & MEM_CGROUP_RECLAIM_NOSWAP;
1371 bool shrink = reclaim_options & MEM_CGROUP_RECLAIM_SHRINK;
1372 bool check_soft = reclaim_options & MEM_CGROUP_RECLAIM_SOFT;
1373 unsigned long excess = mem_cgroup_get_excess(root_mem);
1375 /* If memsw_is_minimum==1, swap-out is of-no-use. */
1376 if (root_mem->memsw_is_minimum)
1380 victim = mem_cgroup_select_victim(root_mem);
1381 if (victim == root_mem) {
1384 drain_all_stock_async();
1387 * If we have not been able to reclaim
1388 * anything, it might because there are
1389 * no reclaimable pages under this hierarchy
1391 if (!check_soft || !total) {
1392 css_put(&victim->css);
1396 * We want to do more targetted reclaim.
1397 * excess >> 2 is not to excessive so as to
1398 * reclaim too much, nor too less that we keep
1399 * coming back to reclaim from this cgroup
1401 if (total >= (excess >> 2) ||
1402 (loop > MEM_CGROUP_MAX_RECLAIM_LOOPS)) {
1403 css_put(&victim->css);
1408 if (!mem_cgroup_local_usage(victim)) {
1409 /* this cgroup's local usage == 0 */
1410 css_put(&victim->css);
1413 /* we use swappiness of local cgroup */
1415 ret = mem_cgroup_shrink_node_zone(victim, gfp_mask,
1416 noswap, get_swappiness(victim), zone);
1418 ret = try_to_free_mem_cgroup_pages(victim, gfp_mask,
1419 noswap, get_swappiness(victim));
1420 css_put(&victim->css);
1422 * At shrinking usage, we can't check we should stop here or
1423 * reclaim more. It's depends on callers. last_scanned_child
1424 * will work enough for keeping fairness under tree.
1430 if (res_counter_check_under_soft_limit(&root_mem->res))
1432 } else if (mem_cgroup_check_under_limit(root_mem))
1439 * Check OOM-Killer is already running under our hierarchy.
1440 * If someone is running, return false.
1442 static bool mem_cgroup_oom_lock(struct mem_cgroup *mem)
1444 int x, lock_count = 0;
1445 struct mem_cgroup *iter;
1447 for_each_mem_cgroup_tree(iter, mem) {
1448 x = atomic_inc_return(&iter->oom_lock);
1449 lock_count = max(x, lock_count);
1452 if (lock_count == 1)
1457 static int mem_cgroup_oom_unlock(struct mem_cgroup *mem)
1459 struct mem_cgroup *iter;
1462 * When a new child is created while the hierarchy is under oom,
1463 * mem_cgroup_oom_lock() may not be called. We have to use
1464 * atomic_add_unless() here.
1466 for_each_mem_cgroup_tree(iter, mem)
1467 atomic_add_unless(&iter->oom_lock, -1, 0);
1472 static DEFINE_MUTEX(memcg_oom_mutex);
1473 static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq);
1475 struct oom_wait_info {
1476 struct mem_cgroup *mem;
1480 static int memcg_oom_wake_function(wait_queue_t *wait,
1481 unsigned mode, int sync, void *arg)
1483 struct mem_cgroup *wake_mem = (struct mem_cgroup *)arg;
1484 struct oom_wait_info *oom_wait_info;
1486 oom_wait_info = container_of(wait, struct oom_wait_info, wait);
1488 if (oom_wait_info->mem == wake_mem)
1490 /* if no hierarchy, no match */
1491 if (!oom_wait_info->mem->use_hierarchy || !wake_mem->use_hierarchy)
1494 * Both of oom_wait_info->mem and wake_mem are stable under us.
1495 * Then we can use css_is_ancestor without taking care of RCU.
1497 if (!css_is_ancestor(&oom_wait_info->mem->css, &wake_mem->css) &&
1498 !css_is_ancestor(&wake_mem->css, &oom_wait_info->mem->css))
1502 return autoremove_wake_function(wait, mode, sync, arg);
1505 static void memcg_wakeup_oom(struct mem_cgroup *mem)
1507 /* for filtering, pass "mem" as argument. */
1508 __wake_up(&memcg_oom_waitq, TASK_NORMAL, 0, mem);
1511 static void memcg_oom_recover(struct mem_cgroup *mem)
1513 if (mem && atomic_read(&mem->oom_lock))
1514 memcg_wakeup_oom(mem);
1518 * try to call OOM killer. returns false if we should exit memory-reclaim loop.
1520 bool mem_cgroup_handle_oom(struct mem_cgroup *mem, gfp_t mask)
1522 struct oom_wait_info owait;
1523 bool locked, need_to_kill;
1526 owait.wait.flags = 0;
1527 owait.wait.func = memcg_oom_wake_function;
1528 owait.wait.private = current;
1529 INIT_LIST_HEAD(&owait.wait.task_list);
1530 need_to_kill = true;
1531 /* At first, try to OOM lock hierarchy under mem.*/
1532 mutex_lock(&memcg_oom_mutex);
1533 locked = mem_cgroup_oom_lock(mem);
1535 * Even if signal_pending(), we can't quit charge() loop without
1536 * accounting. So, UNINTERRUPTIBLE is appropriate. But SIGKILL
1537 * under OOM is always welcomed, use TASK_KILLABLE here.
1539 prepare_to_wait(&memcg_oom_waitq, &owait.wait, TASK_KILLABLE);
1540 if (!locked || mem->oom_kill_disable)
1541 need_to_kill = false;
1543 mem_cgroup_oom_notify(mem);
1544 mutex_unlock(&memcg_oom_mutex);
1547 finish_wait(&memcg_oom_waitq, &owait.wait);
1548 mem_cgroup_out_of_memory(mem, mask);
1551 finish_wait(&memcg_oom_waitq, &owait.wait);
1553 mutex_lock(&memcg_oom_mutex);
1554 mem_cgroup_oom_unlock(mem);
1555 memcg_wakeup_oom(mem);
1556 mutex_unlock(&memcg_oom_mutex);
1558 if (test_thread_flag(TIF_MEMDIE) || fatal_signal_pending(current))
1560 /* Give chance to dying process */
1561 schedule_timeout(1);
1566 * Currently used to update mapped file statistics, but the routine can be
1567 * generalized to update other statistics as well.
1569 * Notes: Race condition
1571 * We usually use page_cgroup_lock() for accessing page_cgroup member but
1572 * it tends to be costly. But considering some conditions, we doesn't need
1573 * to do so _always_.
1575 * Considering "charge", lock_page_cgroup() is not required because all
1576 * file-stat operations happen after a page is attached to radix-tree. There
1577 * are no race with "charge".
1579 * Considering "uncharge", we know that memcg doesn't clear pc->mem_cgroup
1580 * at "uncharge" intentionally. So, we always see valid pc->mem_cgroup even
1581 * if there are race with "uncharge". Statistics itself is properly handled
1584 * Considering "move", this is an only case we see a race. To make the race
1585 * small, we check MEM_CGROUP_ON_MOVE percpu value and detect there are
1586 * possibility of race condition. If there is, we take a lock.
1588 void mem_cgroup_update_file_mapped(struct page *page, int val)
1590 struct mem_cgroup *mem;
1591 struct page_cgroup *pc = lookup_page_cgroup(page);
1592 bool need_unlock = false;
1598 mem = pc->mem_cgroup;
1599 if (unlikely(!mem || !PageCgroupUsed(pc)))
1601 /* pc->mem_cgroup is unstable ? */
1602 if (unlikely(mem_cgroup_stealed(mem))) {
1603 /* take a lock against to access pc->mem_cgroup */
1604 lock_page_cgroup(pc);
1606 mem = pc->mem_cgroup;
1607 if (!mem || !PageCgroupUsed(pc))
1611 this_cpu_inc(mem->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]);
1612 SetPageCgroupFileMapped(pc);
1614 this_cpu_dec(mem->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]);
1615 if (!page_mapped(page)) /* for race between dec->inc counter */
1616 ClearPageCgroupFileMapped(pc);
1620 if (unlikely(need_unlock))
1621 unlock_page_cgroup(pc);
1627 * size of first charge trial. "32" comes from vmscan.c's magic value.
1628 * TODO: maybe necessary to use big numbers in big irons.
1630 #define CHARGE_SIZE (32 * PAGE_SIZE)
1631 struct memcg_stock_pcp {
1632 struct mem_cgroup *cached; /* this never be root cgroup */
1634 struct work_struct work;
1636 static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock);
1637 static atomic_t memcg_drain_count;
1640 * Try to consume stocked charge on this cpu. If success, PAGE_SIZE is consumed
1641 * from local stock and true is returned. If the stock is 0 or charges from a
1642 * cgroup which is not current target, returns false. This stock will be
1645 static bool consume_stock(struct mem_cgroup *mem)
1647 struct memcg_stock_pcp *stock;
1650 stock = &get_cpu_var(memcg_stock);
1651 if (mem == stock->cached && stock->charge)
1652 stock->charge -= PAGE_SIZE;
1653 else /* need to call res_counter_charge */
1655 put_cpu_var(memcg_stock);
1660 * Returns stocks cached in percpu to res_counter and reset cached information.
1662 static void drain_stock(struct memcg_stock_pcp *stock)
1664 struct mem_cgroup *old = stock->cached;
1666 if (stock->charge) {
1667 res_counter_uncharge(&old->res, stock->charge);
1668 if (do_swap_account)
1669 res_counter_uncharge(&old->memsw, stock->charge);
1671 stock->cached = NULL;
1676 * This must be called under preempt disabled or must be called by
1677 * a thread which is pinned to local cpu.
1679 static void drain_local_stock(struct work_struct *dummy)
1681 struct memcg_stock_pcp *stock = &__get_cpu_var(memcg_stock);
1686 * Cache charges(val) which is from res_counter, to local per_cpu area.
1687 * This will be consumed by consume_stock() function, later.
1689 static void refill_stock(struct mem_cgroup *mem, int val)
1691 struct memcg_stock_pcp *stock = &get_cpu_var(memcg_stock);
1693 if (stock->cached != mem) { /* reset if necessary */
1695 stock->cached = mem;
1697 stock->charge += val;
1698 put_cpu_var(memcg_stock);
1702 * Tries to drain stocked charges in other cpus. This function is asynchronous
1703 * and just put a work per cpu for draining localy on each cpu. Caller can
1704 * expects some charges will be back to res_counter later but cannot wait for
1707 static void drain_all_stock_async(void)
1710 /* This function is for scheduling "drain" in asynchronous way.
1711 * The result of "drain" is not directly handled by callers. Then,
1712 * if someone is calling drain, we don't have to call drain more.
1713 * Anyway, WORK_STRUCT_PENDING check in queue_work_on() will catch if
1714 * there is a race. We just do loose check here.
1716 if (atomic_read(&memcg_drain_count))
1718 /* Notify other cpus that system-wide "drain" is running */
1719 atomic_inc(&memcg_drain_count);
1721 for_each_online_cpu(cpu) {
1722 struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
1723 schedule_work_on(cpu, &stock->work);
1726 atomic_dec(&memcg_drain_count);
1727 /* We don't wait for flush_work */
1730 /* This is a synchronous drain interface. */
1731 static void drain_all_stock_sync(void)
1733 /* called when force_empty is called */
1734 atomic_inc(&memcg_drain_count);
1735 schedule_on_each_cpu(drain_local_stock);
1736 atomic_dec(&memcg_drain_count);
1740 * This function drains percpu counter value from DEAD cpu and
1741 * move it to local cpu. Note that this function can be preempted.
1743 static void mem_cgroup_drain_pcp_counter(struct mem_cgroup *mem, int cpu)
1747 spin_lock(&mem->pcp_counter_lock);
1748 for (i = 0; i < MEM_CGROUP_STAT_DATA; i++) {
1749 s64 x = per_cpu(mem->stat->count[i], cpu);
1751 per_cpu(mem->stat->count[i], cpu) = 0;
1752 mem->nocpu_base.count[i] += x;
1754 spin_unlock(&mem->pcp_counter_lock);
1757 static int __cpuinit memcg_cpu_hotplug_callback(struct notifier_block *nb,
1758 unsigned long action,
1761 int cpu = (unsigned long)hcpu;
1762 struct memcg_stock_pcp *stock;
1763 struct mem_cgroup *iter;
1765 if ((action != CPU_DEAD) || action != CPU_DEAD_FROZEN)
1768 for_each_mem_cgroup_all(iter)
1769 mem_cgroup_drain_pcp_counter(iter, cpu);
1771 stock = &per_cpu(memcg_stock, cpu);
1777 /* See __mem_cgroup_try_charge() for details */
1779 CHARGE_OK, /* success */
1780 CHARGE_RETRY, /* need to retry but retry is not bad */
1781 CHARGE_NOMEM, /* we can't do more. return -ENOMEM */
1782 CHARGE_WOULDBLOCK, /* GFP_WAIT wasn't set and no enough res. */
1783 CHARGE_OOM_DIE, /* the current is killed because of OOM */
1786 static int __mem_cgroup_do_charge(struct mem_cgroup *mem, gfp_t gfp_mask,
1787 int csize, bool oom_check)
1789 struct mem_cgroup *mem_over_limit;
1790 struct res_counter *fail_res;
1791 unsigned long flags = 0;
1794 ret = res_counter_charge(&mem->res, csize, &fail_res);
1797 if (!do_swap_account)
1799 ret = res_counter_charge(&mem->memsw, csize, &fail_res);
1803 mem_over_limit = mem_cgroup_from_res_counter(fail_res, memsw);
1804 flags |= MEM_CGROUP_RECLAIM_NOSWAP;
1806 mem_over_limit = mem_cgroup_from_res_counter(fail_res, res);
1808 if (csize > PAGE_SIZE) /* change csize and retry */
1809 return CHARGE_RETRY;
1811 if (!(gfp_mask & __GFP_WAIT))
1812 return CHARGE_WOULDBLOCK;
1814 ret = mem_cgroup_hierarchical_reclaim(mem_over_limit, NULL,
1817 * try_to_free_mem_cgroup_pages() might not give us a full
1818 * picture of reclaim. Some pages are reclaimed and might be
1819 * moved to swap cache or just unmapped from the cgroup.
1820 * Check the limit again to see if the reclaim reduced the
1821 * current usage of the cgroup before giving up
1823 if (ret || mem_cgroup_check_under_limit(mem_over_limit))
1824 return CHARGE_RETRY;
1827 * At task move, charge accounts can be doubly counted. So, it's
1828 * better to wait until the end of task_move if something is going on.
1830 if (mem_cgroup_wait_acct_move(mem_over_limit))
1831 return CHARGE_RETRY;
1833 /* If we don't need to call oom-killer at el, return immediately */
1835 return CHARGE_NOMEM;
1837 if (!mem_cgroup_handle_oom(mem_over_limit, gfp_mask))
1838 return CHARGE_OOM_DIE;
1840 return CHARGE_RETRY;
1844 * Unlike exported interface, "oom" parameter is added. if oom==true,
1845 * oom-killer can be invoked.
1847 static int __mem_cgroup_try_charge(struct mm_struct *mm,
1848 gfp_t gfp_mask, struct mem_cgroup **memcg, bool oom)
1850 int nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES;
1851 struct mem_cgroup *mem = NULL;
1853 int csize = CHARGE_SIZE;
1856 * Unlike gloval-vm's OOM-kill, we're not in memory shortage
1857 * in system level. So, allow to go ahead dying process in addition to
1860 if (unlikely(test_thread_flag(TIF_MEMDIE)
1861 || fatal_signal_pending(current)))
1865 * We always charge the cgroup the mm_struct belongs to.
1866 * The mm_struct's mem_cgroup changes on task migration if the
1867 * thread group leader migrates. It's possible that mm is not
1868 * set, if so charge the init_mm (happens for pagecache usage).
1873 if (*memcg) { /* css should be a valid one */
1875 VM_BUG_ON(css_is_removed(&mem->css));
1876 if (mem_cgroup_is_root(mem))
1878 if (consume_stock(mem))
1882 struct task_struct *p;
1885 p = rcu_dereference(mm->owner);
1888 * because we don't have task_lock(), "p" can exit while
1889 * we're here. In that case, "mem" can point to root
1890 * cgroup but never be NULL. (and task_struct itself is freed
1891 * by RCU, cgroup itself is RCU safe.) Then, we have small
1892 * risk here to get wrong cgroup. But such kind of mis-account
1893 * by race always happens because we don't have cgroup_mutex().
1894 * It's overkill and we allow that small race, here.
1896 mem = mem_cgroup_from_task(p);
1898 if (mem_cgroup_is_root(mem)) {
1902 if (consume_stock(mem)) {
1904 * It seems dagerous to access memcg without css_get().
1905 * But considering how consume_stok works, it's not
1906 * necessary. If consume_stock success, some charges
1907 * from this memcg are cached on this cpu. So, we
1908 * don't need to call css_get()/css_tryget() before
1909 * calling consume_stock().
1914 /* after here, we may be blocked. we need to get refcnt */
1915 if (!css_tryget(&mem->css)) {
1925 /* If killed, bypass charge */
1926 if (fatal_signal_pending(current)) {
1932 if (oom && !nr_oom_retries) {
1934 nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES;
1937 ret = __mem_cgroup_do_charge(mem, gfp_mask, csize, oom_check);
1942 case CHARGE_RETRY: /* not in OOM situation but retry */
1947 case CHARGE_WOULDBLOCK: /* !__GFP_WAIT */
1950 case CHARGE_NOMEM: /* OOM routine works */
1955 /* If oom, we never return -ENOMEM */
1958 case CHARGE_OOM_DIE: /* Killed by OOM Killer */
1962 } while (ret != CHARGE_OK);
1964 if (csize > PAGE_SIZE)
1965 refill_stock(mem, csize - PAGE_SIZE);
1979 * Somemtimes we have to undo a charge we got by try_charge().
1980 * This function is for that and do uncharge, put css's refcnt.
1981 * gotten by try_charge().
1983 static void __mem_cgroup_cancel_charge(struct mem_cgroup *mem,
1984 unsigned long count)
1986 if (!mem_cgroup_is_root(mem)) {
1987 res_counter_uncharge(&mem->res, PAGE_SIZE * count);
1988 if (do_swap_account)
1989 res_counter_uncharge(&mem->memsw, PAGE_SIZE * count);
1993 static void mem_cgroup_cancel_charge(struct mem_cgroup *mem)
1995 __mem_cgroup_cancel_charge(mem, 1);
1999 * A helper function to get mem_cgroup from ID. must be called under
2000 * rcu_read_lock(). The caller must check css_is_removed() or some if
2001 * it's concern. (dropping refcnt from swap can be called against removed
2004 static struct mem_cgroup *mem_cgroup_lookup(unsigned short id)
2006 struct cgroup_subsys_state *css;
2008 /* ID 0 is unused ID */
2011 css = css_lookup(&mem_cgroup_subsys, id);
2014 return container_of(css, struct mem_cgroup, css);
2017 struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page)
2019 struct mem_cgroup *mem = NULL;
2020 struct page_cgroup *pc;
2024 VM_BUG_ON(!PageLocked(page));
2026 pc = lookup_page_cgroup(page);
2027 lock_page_cgroup(pc);
2028 if (PageCgroupUsed(pc)) {
2029 mem = pc->mem_cgroup;
2030 if (mem && !css_tryget(&mem->css))
2032 } else if (PageSwapCache(page)) {
2033 ent.val = page_private(page);
2034 id = lookup_swap_cgroup(ent);
2036 mem = mem_cgroup_lookup(id);
2037 if (mem && !css_tryget(&mem->css))
2041 unlock_page_cgroup(pc);
2046 * commit a charge got by __mem_cgroup_try_charge() and makes page_cgroup to be
2047 * USED state. If already USED, uncharge and return.
2050 static void __mem_cgroup_commit_charge(struct mem_cgroup *mem,
2051 struct page_cgroup *pc,
2052 enum charge_type ctype)
2054 /* try_charge() can return NULL to *memcg, taking care of it. */
2058 lock_page_cgroup(pc);
2059 if (unlikely(PageCgroupUsed(pc))) {
2060 unlock_page_cgroup(pc);
2061 mem_cgroup_cancel_charge(mem);
2065 pc->mem_cgroup = mem;
2067 * We access a page_cgroup asynchronously without lock_page_cgroup().
2068 * Especially when a page_cgroup is taken from a page, pc->mem_cgroup
2069 * is accessed after testing USED bit. To make pc->mem_cgroup visible
2070 * before USED bit, we need memory barrier here.
2071 * See mem_cgroup_add_lru_list(), etc.
2075 case MEM_CGROUP_CHARGE_TYPE_CACHE:
2076 case MEM_CGROUP_CHARGE_TYPE_SHMEM:
2077 SetPageCgroupCache(pc);
2078 SetPageCgroupUsed(pc);
2080 case MEM_CGROUP_CHARGE_TYPE_MAPPED:
2081 ClearPageCgroupCache(pc);
2082 SetPageCgroupUsed(pc);
2088 mem_cgroup_charge_statistics(mem, pc, true);
2090 unlock_page_cgroup(pc);
2092 * "charge_statistics" updated event counter. Then, check it.
2093 * Insert ancestor (and ancestor's ancestors), to softlimit RB-tree.
2094 * if they exceeds softlimit.
2096 memcg_check_events(mem, pc->page);
2100 * __mem_cgroup_move_account - move account of the page
2101 * @pc: page_cgroup of the page.
2102 * @from: mem_cgroup which the page is moved from.
2103 * @to: mem_cgroup which the page is moved to. @from != @to.
2104 * @uncharge: whether we should call uncharge and css_put against @from.
2106 * The caller must confirm following.
2107 * - page is not on LRU (isolate_page() is useful.)
2108 * - the pc is locked, used, and ->mem_cgroup points to @from.
2110 * This function doesn't do "charge" nor css_get to new cgroup. It should be
2111 * done by a caller(__mem_cgroup_try_charge would be usefull). If @uncharge is
2112 * true, this function does "uncharge" from old cgroup, but it doesn't if
2113 * @uncharge is false, so a caller should do "uncharge".
2116 static void __mem_cgroup_move_account(struct page_cgroup *pc,
2117 struct mem_cgroup *from, struct mem_cgroup *to, bool uncharge)
2119 VM_BUG_ON(from == to);
2120 VM_BUG_ON(PageLRU(pc->page));
2121 VM_BUG_ON(!PageCgroupLocked(pc));
2122 VM_BUG_ON(!PageCgroupUsed(pc));
2123 VM_BUG_ON(pc->mem_cgroup != from);
2125 if (PageCgroupFileMapped(pc)) {
2126 /* Update mapped_file data for mem_cgroup */
2128 __this_cpu_dec(from->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]);
2129 __this_cpu_inc(to->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]);
2132 mem_cgroup_charge_statistics(from, pc, false);
2134 /* This is not "cancel", but cancel_charge does all we need. */
2135 mem_cgroup_cancel_charge(from);
2137 /* caller should have done css_get */
2138 pc->mem_cgroup = to;
2139 mem_cgroup_charge_statistics(to, pc, true);
2141 * We charges against "to" which may not have any tasks. Then, "to"
2142 * can be under rmdir(). But in current implementation, caller of
2143 * this function is just force_empty() and move charge, so it's
2144 * garanteed that "to" is never removed. So, we don't check rmdir
2150 * check whether the @pc is valid for moving account and call
2151 * __mem_cgroup_move_account()
2153 static int mem_cgroup_move_account(struct page_cgroup *pc,
2154 struct mem_cgroup *from, struct mem_cgroup *to, bool uncharge)
2157 lock_page_cgroup(pc);
2158 if (PageCgroupUsed(pc) && pc->mem_cgroup == from) {
2159 __mem_cgroup_move_account(pc, from, to, uncharge);
2162 unlock_page_cgroup(pc);
2166 memcg_check_events(to, pc->page);
2167 memcg_check_events(from, pc->page);
2172 * move charges to its parent.
2175 static int mem_cgroup_move_parent(struct page_cgroup *pc,
2176 struct mem_cgroup *child,
2179 struct page *page = pc->page;
2180 struct cgroup *cg = child->css.cgroup;
2181 struct cgroup *pcg = cg->parent;
2182 struct mem_cgroup *parent;
2190 if (!get_page_unless_zero(page))
2192 if (isolate_lru_page(page))
2195 parent = mem_cgroup_from_cont(pcg);
2196 ret = __mem_cgroup_try_charge(NULL, gfp_mask, &parent, false);
2200 ret = mem_cgroup_move_account(pc, child, parent, true);
2202 mem_cgroup_cancel_charge(parent);
2204 putback_lru_page(page);
2212 * Charge the memory controller for page usage.
2214 * 0 if the charge was successful
2215 * < 0 if the cgroup is over its limit
2217 static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm,
2218 gfp_t gfp_mask, enum charge_type ctype)
2220 struct mem_cgroup *mem = NULL;
2221 struct page_cgroup *pc;
2224 pc = lookup_page_cgroup(page);
2225 /* can happen at boot */
2230 ret = __mem_cgroup_try_charge(mm, gfp_mask, &mem, true);
2234 __mem_cgroup_commit_charge(mem, pc, ctype);
2238 int mem_cgroup_newpage_charge(struct page *page,
2239 struct mm_struct *mm, gfp_t gfp_mask)
2241 if (mem_cgroup_disabled())
2243 if (PageCompound(page))
2246 * If already mapped, we don't have to account.
2247 * If page cache, page->mapping has address_space.
2248 * But page->mapping may have out-of-use anon_vma pointer,
2249 * detecit it by PageAnon() check. newly-mapped-anon's page->mapping
2252 if (page_mapped(page) || (page->mapping && !PageAnon(page)))
2256 return mem_cgroup_charge_common(page, mm, gfp_mask,
2257 MEM_CGROUP_CHARGE_TYPE_MAPPED);
2261 __mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr,
2262 enum charge_type ctype);
2264 int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
2269 if (mem_cgroup_disabled())
2271 if (PageCompound(page))
2274 * Corner case handling. This is called from add_to_page_cache()
2275 * in usual. But some FS (shmem) precharges this page before calling it
2276 * and call add_to_page_cache() with GFP_NOWAIT.
2278 * For GFP_NOWAIT case, the page may be pre-charged before calling
2279 * add_to_page_cache(). (See shmem.c) check it here and avoid to call
2280 * charge twice. (It works but has to pay a bit larger cost.)
2281 * And when the page is SwapCache, it should take swap information
2282 * into account. This is under lock_page() now.
2284 if (!(gfp_mask & __GFP_WAIT)) {
2285 struct page_cgroup *pc;
2287 pc = lookup_page_cgroup(page);
2290 lock_page_cgroup(pc);
2291 if (PageCgroupUsed(pc)) {
2292 unlock_page_cgroup(pc);
2295 unlock_page_cgroup(pc);
2301 if (page_is_file_cache(page))
2302 return mem_cgroup_charge_common(page, mm, gfp_mask,
2303 MEM_CGROUP_CHARGE_TYPE_CACHE);
2306 if (PageSwapCache(page)) {
2307 struct mem_cgroup *mem = NULL;
2309 ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &mem);
2311 __mem_cgroup_commit_charge_swapin(page, mem,
2312 MEM_CGROUP_CHARGE_TYPE_SHMEM);
2314 ret = mem_cgroup_charge_common(page, mm, gfp_mask,
2315 MEM_CGROUP_CHARGE_TYPE_SHMEM);
2321 * While swap-in, try_charge -> commit or cancel, the page is locked.
2322 * And when try_charge() successfully returns, one refcnt to memcg without
2323 * struct page_cgroup is acquired. This refcnt will be consumed by
2324 * "commit()" or removed by "cancel()"
2326 int mem_cgroup_try_charge_swapin(struct mm_struct *mm,
2328 gfp_t mask, struct mem_cgroup **ptr)
2330 struct mem_cgroup *mem;
2333 if (mem_cgroup_disabled())
2336 if (!do_swap_account)
2339 * A racing thread's fault, or swapoff, may have already updated
2340 * the pte, and even removed page from swap cache: in those cases
2341 * do_swap_page()'s pte_same() test will fail; but there's also a
2342 * KSM case which does need to charge the page.
2344 if (!PageSwapCache(page))
2346 mem = try_get_mem_cgroup_from_page(page);
2350 ret = __mem_cgroup_try_charge(NULL, mask, ptr, true);
2356 return __mem_cgroup_try_charge(mm, mask, ptr, true);
2360 __mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr,
2361 enum charge_type ctype)
2363 struct page_cgroup *pc;
2365 if (mem_cgroup_disabled())
2369 cgroup_exclude_rmdir(&ptr->css);
2370 pc = lookup_page_cgroup(page);
2371 mem_cgroup_lru_del_before_commit_swapcache(page);
2372 __mem_cgroup_commit_charge(ptr, pc, ctype);
2373 mem_cgroup_lru_add_after_commit_swapcache(page);
2375 * Now swap is on-memory. This means this page may be
2376 * counted both as mem and swap....double count.
2377 * Fix it by uncharging from memsw. Basically, this SwapCache is stable
2378 * under lock_page(). But in do_swap_page()::memory.c, reuse_swap_page()
2379 * may call delete_from_swap_cache() before reach here.
2381 if (do_swap_account && PageSwapCache(page)) {
2382 swp_entry_t ent = {.val = page_private(page)};
2384 struct mem_cgroup *memcg;
2386 id = swap_cgroup_record(ent, 0);
2388 memcg = mem_cgroup_lookup(id);
2391 * This recorded memcg can be obsolete one. So, avoid
2392 * calling css_tryget
2394 if (!mem_cgroup_is_root(memcg))
2395 res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
2396 mem_cgroup_swap_statistics(memcg, false);
2397 mem_cgroup_put(memcg);
2402 * At swapin, we may charge account against cgroup which has no tasks.
2403 * So, rmdir()->pre_destroy() can be called while we do this charge.
2404 * In that case, we need to call pre_destroy() again. check it here.
2406 cgroup_release_and_wakeup_rmdir(&ptr->css);
2409 void mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr)
2411 __mem_cgroup_commit_charge_swapin(page, ptr,
2412 MEM_CGROUP_CHARGE_TYPE_MAPPED);
2415 void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *mem)
2417 if (mem_cgroup_disabled())
2421 mem_cgroup_cancel_charge(mem);
2425 __do_uncharge(struct mem_cgroup *mem, const enum charge_type ctype)
2427 struct memcg_batch_info *batch = NULL;
2428 bool uncharge_memsw = true;
2429 /* If swapout, usage of swap doesn't decrease */
2430 if (!do_swap_account || ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT)
2431 uncharge_memsw = false;
2433 batch = ¤t->memcg_batch;
2435 * In usual, we do css_get() when we remember memcg pointer.
2436 * But in this case, we keep res->usage until end of a series of
2437 * uncharges. Then, it's ok to ignore memcg's refcnt.
2442 * do_batch > 0 when unmapping pages or inode invalidate/truncate.
2443 * In those cases, all pages freed continously can be expected to be in
2444 * the same cgroup and we have chance to coalesce uncharges.
2445 * But we do uncharge one by one if this is killed by OOM(TIF_MEMDIE)
2446 * because we want to do uncharge as soon as possible.
2449 if (!batch->do_batch || test_thread_flag(TIF_MEMDIE))
2450 goto direct_uncharge;
2453 * In typical case, batch->memcg == mem. This means we can
2454 * merge a series of uncharges to an uncharge of res_counter.
2455 * If not, we uncharge res_counter ony by one.
2457 if (batch->memcg != mem)
2458 goto direct_uncharge;
2459 /* remember freed charge and uncharge it later */
2460 batch->bytes += PAGE_SIZE;
2462 batch->memsw_bytes += PAGE_SIZE;
2465 res_counter_uncharge(&mem->res, PAGE_SIZE);
2467 res_counter_uncharge(&mem->memsw, PAGE_SIZE);
2468 if (unlikely(batch->memcg != mem))
2469 memcg_oom_recover(mem);
2474 * uncharge if !page_mapped(page)
2476 static struct mem_cgroup *
2477 __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
2479 struct page_cgroup *pc;
2480 struct mem_cgroup *mem = NULL;
2482 if (mem_cgroup_disabled())
2485 if (PageSwapCache(page))
2489 * Check if our page_cgroup is valid
2491 pc = lookup_page_cgroup(page);
2492 if (unlikely(!pc || !PageCgroupUsed(pc)))
2495 lock_page_cgroup(pc);
2497 mem = pc->mem_cgroup;
2499 if (!PageCgroupUsed(pc))
2503 case MEM_CGROUP_CHARGE_TYPE_MAPPED:
2504 case MEM_CGROUP_CHARGE_TYPE_DROP:
2505 /* See mem_cgroup_prepare_migration() */
2506 if (page_mapped(page) || PageCgroupMigration(pc))
2509 case MEM_CGROUP_CHARGE_TYPE_SWAPOUT:
2510 if (!PageAnon(page)) { /* Shared memory */
2511 if (page->mapping && !page_is_file_cache(page))
2513 } else if (page_mapped(page)) /* Anon */
2520 mem_cgroup_charge_statistics(mem, pc, false);
2522 ClearPageCgroupUsed(pc);
2524 * pc->mem_cgroup is not cleared here. It will be accessed when it's
2525 * freed from LRU. This is safe because uncharged page is expected not
2526 * to be reused (freed soon). Exception is SwapCache, it's handled by
2527 * special functions.
2530 unlock_page_cgroup(pc);
2532 * even after unlock, we have mem->res.usage here and this memcg
2533 * will never be freed.
2535 memcg_check_events(mem, page);
2536 if (do_swap_account && ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT) {
2537 mem_cgroup_swap_statistics(mem, true);
2538 mem_cgroup_get(mem);
2540 if (!mem_cgroup_is_root(mem))
2541 __do_uncharge(mem, ctype);
2546 unlock_page_cgroup(pc);
2550 void mem_cgroup_uncharge_page(struct page *page)
2553 if (page_mapped(page))
2555 if (page->mapping && !PageAnon(page))
2557 __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_MAPPED);
2560 void mem_cgroup_uncharge_cache_page(struct page *page)
2562 VM_BUG_ON(page_mapped(page));
2563 VM_BUG_ON(page->mapping);
2564 __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE);
2568 * Batch_start/batch_end is called in unmap_page_range/invlidate/trucate.
2569 * In that cases, pages are freed continuously and we can expect pages
2570 * are in the same memcg. All these calls itself limits the number of
2571 * pages freed at once, then uncharge_start/end() is called properly.
2572 * This may be called prural(2) times in a context,
2575 void mem_cgroup_uncharge_start(void)
2577 current->memcg_batch.do_batch++;
2578 /* We can do nest. */
2579 if (current->memcg_batch.do_batch == 1) {
2580 current->memcg_batch.memcg = NULL;
2581 current->memcg_batch.bytes = 0;
2582 current->memcg_batch.memsw_bytes = 0;
2586 void mem_cgroup_uncharge_end(void)
2588 struct memcg_batch_info *batch = ¤t->memcg_batch;
2590 if (!batch->do_batch)
2594 if (batch->do_batch) /* If stacked, do nothing. */
2600 * This "batch->memcg" is valid without any css_get/put etc...
2601 * bacause we hide charges behind us.
2604 res_counter_uncharge(&batch->memcg->res, batch->bytes);
2605 if (batch->memsw_bytes)
2606 res_counter_uncharge(&batch->memcg->memsw, batch->memsw_bytes);
2607 memcg_oom_recover(batch->memcg);
2608 /* forget this pointer (for sanity check) */
2609 batch->memcg = NULL;
2614 * called after __delete_from_swap_cache() and drop "page" account.
2615 * memcg information is recorded to swap_cgroup of "ent"
2618 mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout)
2620 struct mem_cgroup *memcg;
2621 int ctype = MEM_CGROUP_CHARGE_TYPE_SWAPOUT;
2623 if (!swapout) /* this was a swap cache but the swap is unused ! */
2624 ctype = MEM_CGROUP_CHARGE_TYPE_DROP;
2626 memcg = __mem_cgroup_uncharge_common(page, ctype);
2629 * record memcg information, if swapout && memcg != NULL,
2630 * mem_cgroup_get() was called in uncharge().
2632 if (do_swap_account && swapout && memcg)
2633 swap_cgroup_record(ent, css_id(&memcg->css));
2637 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
2639 * called from swap_entry_free(). remove record in swap_cgroup and
2640 * uncharge "memsw" account.
2642 void mem_cgroup_uncharge_swap(swp_entry_t ent)
2644 struct mem_cgroup *memcg;
2647 if (!do_swap_account)
2650 id = swap_cgroup_record(ent, 0);
2652 memcg = mem_cgroup_lookup(id);
2655 * We uncharge this because swap is freed.
2656 * This memcg can be obsolete one. We avoid calling css_tryget
2658 if (!mem_cgroup_is_root(memcg))
2659 res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
2660 mem_cgroup_swap_statistics(memcg, false);
2661 mem_cgroup_put(memcg);
2667 * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record.
2668 * @entry: swap entry to be moved
2669 * @from: mem_cgroup which the entry is moved from
2670 * @to: mem_cgroup which the entry is moved to
2671 * @need_fixup: whether we should fixup res_counters and refcounts.
2673 * It succeeds only when the swap_cgroup's record for this entry is the same
2674 * as the mem_cgroup's id of @from.
2676 * Returns 0 on success, -EINVAL on failure.
2678 * The caller must have charged to @to, IOW, called res_counter_charge() about
2679 * both res and memsw, and called css_get().
2681 static int mem_cgroup_move_swap_account(swp_entry_t entry,
2682 struct mem_cgroup *from, struct mem_cgroup *to, bool need_fixup)
2684 unsigned short old_id, new_id;
2686 old_id = css_id(&from->css);
2687 new_id = css_id(&to->css);
2689 if (swap_cgroup_cmpxchg(entry, old_id, new_id) == old_id) {
2690 mem_cgroup_swap_statistics(from, false);
2691 mem_cgroup_swap_statistics(to, true);
2693 * This function is only called from task migration context now.
2694 * It postpones res_counter and refcount handling till the end
2695 * of task migration(mem_cgroup_clear_mc()) for performance
2696 * improvement. But we cannot postpone mem_cgroup_get(to)
2697 * because if the process that has been moved to @to does
2698 * swap-in, the refcount of @to might be decreased to 0.
2702 if (!mem_cgroup_is_root(from))
2703 res_counter_uncharge(&from->memsw, PAGE_SIZE);
2704 mem_cgroup_put(from);
2706 * we charged both to->res and to->memsw, so we should
2709 if (!mem_cgroup_is_root(to))
2710 res_counter_uncharge(&to->res, PAGE_SIZE);
2717 static inline int mem_cgroup_move_swap_account(swp_entry_t entry,
2718 struct mem_cgroup *from, struct mem_cgroup *to, bool need_fixup)
2725 * Before starting migration, account PAGE_SIZE to mem_cgroup that the old
2728 int mem_cgroup_prepare_migration(struct page *page,
2729 struct page *newpage, struct mem_cgroup **ptr)
2731 struct page_cgroup *pc;
2732 struct mem_cgroup *mem = NULL;
2733 enum charge_type ctype;
2736 if (mem_cgroup_disabled())
2739 pc = lookup_page_cgroup(page);
2740 lock_page_cgroup(pc);
2741 if (PageCgroupUsed(pc)) {
2742 mem = pc->mem_cgroup;
2745 * At migrating an anonymous page, its mapcount goes down
2746 * to 0 and uncharge() will be called. But, even if it's fully
2747 * unmapped, migration may fail and this page has to be
2748 * charged again. We set MIGRATION flag here and delay uncharge
2749 * until end_migration() is called
2751 * Corner Case Thinking
2753 * When the old page was mapped as Anon and it's unmap-and-freed
2754 * while migration was ongoing.
2755 * If unmap finds the old page, uncharge() of it will be delayed
2756 * until end_migration(). If unmap finds a new page, it's
2757 * uncharged when it make mapcount to be 1->0. If unmap code
2758 * finds swap_migration_entry, the new page will not be mapped
2759 * and end_migration() will find it(mapcount==0).
2762 * When the old page was mapped but migraion fails, the kernel
2763 * remaps it. A charge for it is kept by MIGRATION flag even
2764 * if mapcount goes down to 0. We can do remap successfully
2765 * without charging it again.
2768 * The "old" page is under lock_page() until the end of
2769 * migration, so, the old page itself will not be swapped-out.
2770 * If the new page is swapped out before end_migraton, our
2771 * hook to usual swap-out path will catch the event.
2774 SetPageCgroupMigration(pc);
2776 unlock_page_cgroup(pc);
2778 * If the page is not charged at this point,
2785 ret = __mem_cgroup_try_charge(NULL, GFP_KERNEL, ptr, false);
2786 css_put(&mem->css);/* drop extra refcnt */
2787 if (ret || *ptr == NULL) {
2788 if (PageAnon(page)) {
2789 lock_page_cgroup(pc);
2790 ClearPageCgroupMigration(pc);
2791 unlock_page_cgroup(pc);
2793 * The old page may be fully unmapped while we kept it.
2795 mem_cgroup_uncharge_page(page);
2800 * We charge new page before it's used/mapped. So, even if unlock_page()
2801 * is called before end_migration, we can catch all events on this new
2802 * page. In the case new page is migrated but not remapped, new page's
2803 * mapcount will be finally 0 and we call uncharge in end_migration().
2805 pc = lookup_page_cgroup(newpage);
2807 ctype = MEM_CGROUP_CHARGE_TYPE_MAPPED;
2808 else if (page_is_file_cache(page))
2809 ctype = MEM_CGROUP_CHARGE_TYPE_CACHE;
2811 ctype = MEM_CGROUP_CHARGE_TYPE_SHMEM;
2812 __mem_cgroup_commit_charge(mem, pc, ctype);
2816 /* remove redundant charge if migration failed*/
2817 void mem_cgroup_end_migration(struct mem_cgroup *mem,
2818 struct page *oldpage, struct page *newpage)
2820 struct page *used, *unused;
2821 struct page_cgroup *pc;
2825 /* blocks rmdir() */
2826 cgroup_exclude_rmdir(&mem->css);
2827 /* at migration success, oldpage->mapping is NULL. */
2828 if (oldpage->mapping) {
2836 * We disallowed uncharge of pages under migration because mapcount
2837 * of the page goes down to zero, temporarly.
2838 * Clear the flag and check the page should be charged.
2840 pc = lookup_page_cgroup(oldpage);
2841 lock_page_cgroup(pc);
2842 ClearPageCgroupMigration(pc);
2843 unlock_page_cgroup(pc);
2845 __mem_cgroup_uncharge_common(unused, MEM_CGROUP_CHARGE_TYPE_FORCE);
2848 * If a page is a file cache, radix-tree replacement is very atomic
2849 * and we can skip this check. When it was an Anon page, its mapcount
2850 * goes down to 0. But because we added MIGRATION flage, it's not
2851 * uncharged yet. There are several case but page->mapcount check
2852 * and USED bit check in mem_cgroup_uncharge_page() will do enough
2853 * check. (see prepare_charge() also)
2856 mem_cgroup_uncharge_page(used);
2858 * At migration, we may charge account against cgroup which has no
2860 * So, rmdir()->pre_destroy() can be called while we do this charge.
2861 * In that case, we need to call pre_destroy() again. check it here.
2863 cgroup_release_and_wakeup_rmdir(&mem->css);
2867 * A call to try to shrink memory usage on charge failure at shmem's swapin.
2868 * Calling hierarchical_reclaim is not enough because we should update
2869 * last_oom_jiffies to prevent pagefault_out_of_memory from invoking global OOM.
2870 * Moreover considering hierarchy, we should reclaim from the mem_over_limit,
2871 * not from the memcg which this page would be charged to.
2872 * try_charge_swapin does all of these works properly.
2874 int mem_cgroup_shmem_charge_fallback(struct page *page,
2875 struct mm_struct *mm,
2878 struct mem_cgroup *mem = NULL;
2881 if (mem_cgroup_disabled())
2884 ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &mem);
2886 mem_cgroup_cancel_charge_swapin(mem); /* it does !mem check */
2891 static DEFINE_MUTEX(set_limit_mutex);
2893 static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
2894 unsigned long long val)
2897 u64 memswlimit, memlimit;
2899 int children = mem_cgroup_count_children(memcg);
2900 u64 curusage, oldusage;
2904 * For keeping hierarchical_reclaim simple, how long we should retry
2905 * is depends on callers. We set our retry-count to be function
2906 * of # of children which we should visit in this loop.
2908 retry_count = MEM_CGROUP_RECLAIM_RETRIES * children;
2910 oldusage = res_counter_read_u64(&memcg->res, RES_USAGE);
2913 while (retry_count) {
2914 if (signal_pending(current)) {
2919 * Rather than hide all in some function, I do this in
2920 * open coded manner. You see what this really does.
2921 * We have to guarantee mem->res.limit < mem->memsw.limit.
2923 mutex_lock(&set_limit_mutex);
2924 memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
2925 if (memswlimit < val) {
2927 mutex_unlock(&set_limit_mutex);
2931 memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT);
2935 ret = res_counter_set_limit(&memcg->res, val);
2937 if (memswlimit == val)
2938 memcg->memsw_is_minimum = true;
2940 memcg->memsw_is_minimum = false;
2942 mutex_unlock(&set_limit_mutex);
2947 mem_cgroup_hierarchical_reclaim(memcg, NULL, GFP_KERNEL,
2948 MEM_CGROUP_RECLAIM_SHRINK);
2949 curusage = res_counter_read_u64(&memcg->res, RES_USAGE);
2950 /* Usage is reduced ? */
2951 if (curusage >= oldusage)
2954 oldusage = curusage;
2956 if (!ret && enlarge)
2957 memcg_oom_recover(memcg);
2962 static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
2963 unsigned long long val)
2966 u64 memlimit, memswlimit, oldusage, curusage;
2967 int children = mem_cgroup_count_children(memcg);
2971 /* see mem_cgroup_resize_res_limit */
2972 retry_count = children * MEM_CGROUP_RECLAIM_RETRIES;
2973 oldusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
2974 while (retry_count) {
2975 if (signal_pending(current)) {
2980 * Rather than hide all in some function, I do this in
2981 * open coded manner. You see what this really does.
2982 * We have to guarantee mem->res.limit < mem->memsw.limit.
2984 mutex_lock(&set_limit_mutex);
2985 memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT);
2986 if (memlimit > val) {
2988 mutex_unlock(&set_limit_mutex);
2991 memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
2992 if (memswlimit < val)
2994 ret = res_counter_set_limit(&memcg->memsw, val);
2996 if (memlimit == val)
2997 memcg->memsw_is_minimum = true;
2999 memcg->memsw_is_minimum = false;
3001 mutex_unlock(&set_limit_mutex);
3006 mem_cgroup_hierarchical_reclaim(memcg, NULL, GFP_KERNEL,
3007 MEM_CGROUP_RECLAIM_NOSWAP |
3008 MEM_CGROUP_RECLAIM_SHRINK);
3009 curusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
3010 /* Usage is reduced ? */
3011 if (curusage >= oldusage)
3014 oldusage = curusage;
3016 if (!ret && enlarge)
3017 memcg_oom_recover(memcg);
3021 unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
3024 unsigned long nr_reclaimed = 0;
3025 struct mem_cgroup_per_zone *mz, *next_mz = NULL;
3026 unsigned long reclaimed;
3028 struct mem_cgroup_tree_per_zone *mctz;
3029 unsigned long long excess;
3034 mctz = soft_limit_tree_node_zone(zone_to_nid(zone), zone_idx(zone));
3036 * This loop can run a while, specially if mem_cgroup's continuously
3037 * keep exceeding their soft limit and putting the system under
3044 mz = mem_cgroup_largest_soft_limit_node(mctz);
3048 reclaimed = mem_cgroup_hierarchical_reclaim(mz->mem, zone,
3050 MEM_CGROUP_RECLAIM_SOFT);
3051 nr_reclaimed += reclaimed;
3052 spin_lock(&mctz->lock);
3055 * If we failed to reclaim anything from this memory cgroup
3056 * it is time to move on to the next cgroup
3062 * Loop until we find yet another one.
3064 * By the time we get the soft_limit lock
3065 * again, someone might have aded the
3066 * group back on the RB tree. Iterate to
3067 * make sure we get a different mem.
3068 * mem_cgroup_largest_soft_limit_node returns
3069 * NULL if no other cgroup is present on
3073 __mem_cgroup_largest_soft_limit_node(mctz);
3074 if (next_mz == mz) {
3075 css_put(&next_mz->mem->css);
3077 } else /* next_mz == NULL or other memcg */
3081 __mem_cgroup_remove_exceeded(mz->mem, mz, mctz);
3082 excess = res_counter_soft_limit_excess(&mz->mem->res);
3084 * One school of thought says that we should not add
3085 * back the node to the tree if reclaim returns 0.
3086 * But our reclaim could return 0, simply because due
3087 * to priority we are exposing a smaller subset of
3088 * memory to reclaim from. Consider this as a longer
3091 /* If excess == 0, no tree ops */
3092 __mem_cgroup_insert_exceeded(mz->mem, mz, mctz, excess);
3093 spin_unlock(&mctz->lock);
3094 css_put(&mz->mem->css);
3097 * Could not reclaim anything and there are no more
3098 * mem cgroups to try or we seem to be looping without
3099 * reclaiming anything.
3101 if (!nr_reclaimed &&
3103 loop > MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS))
3105 } while (!nr_reclaimed);
3107 css_put(&next_mz->mem->css);
3108 return nr_reclaimed;
3112 * This routine traverse page_cgroup in given list and drop them all.
3113 * *And* this routine doesn't reclaim page itself, just removes page_cgroup.
3115 static int mem_cgroup_force_empty_list(struct mem_cgroup *mem,
3116 int node, int zid, enum lru_list lru)
3119 struct mem_cgroup_per_zone *mz;
3120 struct page_cgroup *pc, *busy;
3121 unsigned long flags, loop;
3122 struct list_head *list;
3125 zone = &NODE_DATA(node)->node_zones[zid];
3126 mz = mem_cgroup_zoneinfo(mem, node, zid);
3127 list = &mz->lists[lru];
3129 loop = MEM_CGROUP_ZSTAT(mz, lru);
3130 /* give some margin against EBUSY etc...*/
3135 spin_lock_irqsave(&zone->lru_lock, flags);
3136 if (list_empty(list)) {
3137 spin_unlock_irqrestore(&zone->lru_lock, flags);
3140 pc = list_entry(list->prev, struct page_cgroup, lru);
3142 list_move(&pc->lru, list);
3144 spin_unlock_irqrestore(&zone->lru_lock, flags);
3147 spin_unlock_irqrestore(&zone->lru_lock, flags);
3149 ret = mem_cgroup_move_parent(pc, mem, GFP_KERNEL);
3153 if (ret == -EBUSY || ret == -EINVAL) {
3154 /* found lock contention or "pc" is obsolete. */
3161 if (!ret && !list_empty(list))
3167 * make mem_cgroup's charge to be 0 if there is no task.
3168 * This enables deleting this mem_cgroup.
3170 static int mem_cgroup_force_empty(struct mem_cgroup *mem, bool free_all)
3173 int node, zid, shrink;
3174 int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
3175 struct cgroup *cgrp = mem->css.cgroup;
3180 /* should free all ? */
3186 if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children))
3189 if (signal_pending(current))
3191 /* This is for making all *used* pages to be on LRU. */
3192 lru_add_drain_all();
3193 drain_all_stock_sync();
3195 mem_cgroup_start_move(mem);
3196 for_each_node_state(node, N_HIGH_MEMORY) {
3197 for (zid = 0; !ret && zid < MAX_NR_ZONES; zid++) {
3200 ret = mem_cgroup_force_empty_list(mem,
3209 mem_cgroup_end_move(mem);
3210 memcg_oom_recover(mem);
3211 /* it seems parent cgroup doesn't have enough mem */
3215 /* "ret" should also be checked to ensure all lists are empty. */
3216 } while (mem->res.usage > 0 || ret);
3222 /* returns EBUSY if there is a task or if we come here twice. */
3223 if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children) || shrink) {
3227 /* we call try-to-free pages for make this cgroup empty */
3228 lru_add_drain_all();
3229 /* try to free all pages in this cgroup */
3231 while (nr_retries && mem->res.usage > 0) {
3234 if (signal_pending(current)) {
3238 progress = try_to_free_mem_cgroup_pages(mem, GFP_KERNEL,
3239 false, get_swappiness(mem));
3242 /* maybe some writeback is necessary */
3243 congestion_wait(BLK_RW_ASYNC, HZ/10);
3248 /* try move_account...there may be some *locked* pages. */
3252 int mem_cgroup_force_empty_write(struct cgroup *cont, unsigned int event)
3254 return mem_cgroup_force_empty(mem_cgroup_from_cont(cont), true);
3258 static u64 mem_cgroup_hierarchy_read(struct cgroup *cont, struct cftype *cft)
3260 return mem_cgroup_from_cont(cont)->use_hierarchy;
3263 static int mem_cgroup_hierarchy_write(struct cgroup *cont, struct cftype *cft,
3267 struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
3268 struct cgroup *parent = cont->parent;
3269 struct mem_cgroup *parent_mem = NULL;
3272 parent_mem = mem_cgroup_from_cont(parent);
3276 * If parent's use_hierarchy is set, we can't make any modifications
3277 * in the child subtrees. If it is unset, then the change can
3278 * occur, provided the current cgroup has no children.
3280 * For the root cgroup, parent_mem is NULL, we allow value to be
3281 * set if there are no children.
3283 if ((!parent_mem || !parent_mem->use_hierarchy) &&
3284 (val == 1 || val == 0)) {
3285 if (list_empty(&cont->children))
3286 mem->use_hierarchy = val;
3297 static u64 mem_cgroup_get_recursive_idx_stat(struct mem_cgroup *mem,
3298 enum mem_cgroup_stat_index idx)
3300 struct mem_cgroup *iter;
3303 /* each per cpu's value can be minus.Then, use s64 */
3304 for_each_mem_cgroup_tree(iter, mem)
3305 val += mem_cgroup_read_stat(iter, idx);
3307 if (val < 0) /* race ? */
3312 static inline u64 mem_cgroup_usage(struct mem_cgroup *mem, bool swap)
3316 if (!mem_cgroup_is_root(mem)) {
3318 return res_counter_read_u64(&mem->res, RES_USAGE);
3320 return res_counter_read_u64(&mem->memsw, RES_USAGE);
3323 val = mem_cgroup_get_recursive_idx_stat(mem, MEM_CGROUP_STAT_CACHE);
3324 val += mem_cgroup_get_recursive_idx_stat(mem, MEM_CGROUP_STAT_RSS);
3327 val += mem_cgroup_get_recursive_idx_stat(mem,
3328 MEM_CGROUP_STAT_SWAPOUT);
3330 return val << PAGE_SHIFT;
3333 static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft)
3335 struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
3339 type = MEMFILE_TYPE(cft->private);
3340 name = MEMFILE_ATTR(cft->private);
3343 if (name == RES_USAGE)
3344 val = mem_cgroup_usage(mem, false);
3346 val = res_counter_read_u64(&mem->res, name);
3349 if (name == RES_USAGE)
3350 val = mem_cgroup_usage(mem, true);
3352 val = res_counter_read_u64(&mem->memsw, name);
3361 * The user of this function is...
3364 static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
3367 struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
3369 unsigned long long val;
3372 type = MEMFILE_TYPE(cft->private);
3373 name = MEMFILE_ATTR(cft->private);
3376 if (mem_cgroup_is_root(memcg)) { /* Can't set limit on root */
3380 /* This function does all necessary parse...reuse it */
3381 ret = res_counter_memparse_write_strategy(buffer, &val);
3385 ret = mem_cgroup_resize_limit(memcg, val);
3387 ret = mem_cgroup_resize_memsw_limit(memcg, val);
3389 case RES_SOFT_LIMIT:
3390 ret = res_counter_memparse_write_strategy(buffer, &val);
3394 * For memsw, soft limits are hard to implement in terms
3395 * of semantics, for now, we support soft limits for
3396 * control without swap
3399 ret = res_counter_set_soft_limit(&memcg->res, val);
3404 ret = -EINVAL; /* should be BUG() ? */
3410 static void memcg_get_hierarchical_limit(struct mem_cgroup *memcg,
3411 unsigned long long *mem_limit, unsigned long long *memsw_limit)
3413 struct cgroup *cgroup;
3414 unsigned long long min_limit, min_memsw_limit, tmp;
3416 min_limit = res_counter_read_u64(&memcg->res, RES_LIMIT);
3417 min_memsw_limit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
3418 cgroup = memcg->css.cgroup;
3419 if (!memcg->use_hierarchy)
3422 while (cgroup->parent) {
3423 cgroup = cgroup->parent;
3424 memcg = mem_cgroup_from_cont(cgroup);
3425 if (!memcg->use_hierarchy)
3427 tmp = res_counter_read_u64(&memcg->res, RES_LIMIT);
3428 min_limit = min(min_limit, tmp);
3429 tmp = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
3430 min_memsw_limit = min(min_memsw_limit, tmp);
3433 *mem_limit = min_limit;
3434 *memsw_limit = min_memsw_limit;
3438 static int mem_cgroup_reset(struct cgroup *cont, unsigned int event)
3440 struct mem_cgroup *mem;
3443 mem = mem_cgroup_from_cont(cont);
3444 type = MEMFILE_TYPE(event);
3445 name = MEMFILE_ATTR(event);
3449 res_counter_reset_max(&mem->res);
3451 res_counter_reset_max(&mem->memsw);
3455 res_counter_reset_failcnt(&mem->res);
3457 res_counter_reset_failcnt(&mem->memsw);
3464 static u64 mem_cgroup_move_charge_read(struct cgroup *cgrp,
3467 return mem_cgroup_from_cont(cgrp)->move_charge_at_immigrate;
3471 static int mem_cgroup_move_charge_write(struct cgroup *cgrp,
3472 struct cftype *cft, u64 val)
3474 struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp);
3476 if (val >= (1 << NR_MOVE_TYPE))
3479 * We check this value several times in both in can_attach() and
3480 * attach(), so we need cgroup lock to prevent this value from being
3484 mem->move_charge_at_immigrate = val;
3490 static int mem_cgroup_move_charge_write(struct cgroup *cgrp,
3491 struct cftype *cft, u64 val)
3498 /* For read statistics */
3514 struct mcs_total_stat {
3515 s64 stat[NR_MCS_STAT];
3521 } memcg_stat_strings[NR_MCS_STAT] = {
3522 {"cache", "total_cache"},
3523 {"rss", "total_rss"},
3524 {"mapped_file", "total_mapped_file"},
3525 {"pgpgin", "total_pgpgin"},
3526 {"pgpgout", "total_pgpgout"},
3527 {"swap", "total_swap"},
3528 {"inactive_anon", "total_inactive_anon"},
3529 {"active_anon", "total_active_anon"},
3530 {"inactive_file", "total_inactive_file"},
3531 {"active_file", "total_active_file"},
3532 {"unevictable", "total_unevictable"}
3537 mem_cgroup_get_local_stat(struct mem_cgroup *mem, struct mcs_total_stat *s)
3542 val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_CACHE);
3543 s->stat[MCS_CACHE] += val * PAGE_SIZE;
3544 val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_RSS);
3545 s->stat[MCS_RSS] += val * PAGE_SIZE;
3546 val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_FILE_MAPPED);
3547 s->stat[MCS_FILE_MAPPED] += val * PAGE_SIZE;
3548 val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_PGPGIN_COUNT);
3549 s->stat[MCS_PGPGIN] += val;
3550 val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_PGPGOUT_COUNT);
3551 s->stat[MCS_PGPGOUT] += val;
3552 if (do_swap_account) {
3553 val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_SWAPOUT);
3554 s->stat[MCS_SWAP] += val * PAGE_SIZE;
3558 val = mem_cgroup_get_local_zonestat(mem, LRU_INACTIVE_ANON);
3559 s->stat[MCS_INACTIVE_ANON] += val * PAGE_SIZE;
3560 val = mem_cgroup_get_local_zonestat(mem, LRU_ACTIVE_ANON);
3561 s->stat[MCS_ACTIVE_ANON] += val * PAGE_SIZE;
3562 val = mem_cgroup_get_local_zonestat(mem, LRU_INACTIVE_FILE);
3563 s->stat[MCS_INACTIVE_FILE] += val * PAGE_SIZE;
3564 val = mem_cgroup_get_local_zonestat(mem, LRU_ACTIVE_FILE);
3565 s->stat[MCS_ACTIVE_FILE] += val * PAGE_SIZE;
3566 val = mem_cgroup_get_local_zonestat(mem, LRU_UNEVICTABLE);
3567 s->stat[MCS_UNEVICTABLE] += val * PAGE_SIZE;
3571 mem_cgroup_get_total_stat(struct mem_cgroup *mem, struct mcs_total_stat *s)
3573 struct mem_cgroup *iter;
3575 for_each_mem_cgroup_tree(iter, mem)
3576 mem_cgroup_get_local_stat(iter, s);
3579 static int mem_control_stat_show(struct cgroup *cont, struct cftype *cft,
3580 struct cgroup_map_cb *cb)
3582 struct mem_cgroup *mem_cont = mem_cgroup_from_cont(cont);
3583 struct mcs_total_stat mystat;
3586 memset(&mystat, 0, sizeof(mystat));
3587 mem_cgroup_get_local_stat(mem_cont, &mystat);
3589 for (i = 0; i < NR_MCS_STAT; i++) {
3590 if (i == MCS_SWAP && !do_swap_account)
3592 cb->fill(cb, memcg_stat_strings[i].local_name, mystat.stat[i]);
3595 /* Hierarchical information */
3597 unsigned long long limit, memsw_limit;
3598 memcg_get_hierarchical_limit(mem_cont, &limit, &memsw_limit);
3599 cb->fill(cb, "hierarchical_memory_limit", limit);
3600 if (do_swap_account)
3601 cb->fill(cb, "hierarchical_memsw_limit", memsw_limit);
3604 memset(&mystat, 0, sizeof(mystat));
3605 mem_cgroup_get_total_stat(mem_cont, &mystat);
3606 for (i = 0; i < NR_MCS_STAT; i++) {
3607 if (i == MCS_SWAP && !do_swap_account)
3609 cb->fill(cb, memcg_stat_strings[i].total_name, mystat.stat[i]);
3612 #ifdef CONFIG_DEBUG_VM
3613 cb->fill(cb, "inactive_ratio", calc_inactive_ratio(mem_cont, NULL));
3617 struct mem_cgroup_per_zone *mz;
3618 unsigned long recent_rotated[2] = {0, 0};
3619 unsigned long recent_scanned[2] = {0, 0};
3621 for_each_online_node(nid)
3622 for (zid = 0; zid < MAX_NR_ZONES; zid++) {
3623 mz = mem_cgroup_zoneinfo(mem_cont, nid, zid);
3625 recent_rotated[0] +=
3626 mz->reclaim_stat.recent_rotated[0];
3627 recent_rotated[1] +=
3628 mz->reclaim_stat.recent_rotated[1];
3629 recent_scanned[0] +=
3630 mz->reclaim_stat.recent_scanned[0];
3631 recent_scanned[1] +=
3632 mz->reclaim_stat.recent_scanned[1];
3634 cb->fill(cb, "recent_rotated_anon", recent_rotated[0]);
3635 cb->fill(cb, "recent_rotated_file", recent_rotated[1]);
3636 cb->fill(cb, "recent_scanned_anon", recent_scanned[0]);
3637 cb->fill(cb, "recent_scanned_file", recent_scanned[1]);
3644 static u64 mem_cgroup_swappiness_read(struct cgroup *cgrp, struct cftype *cft)
3646 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
3648 return get_swappiness(memcg);
3651 static int mem_cgroup_swappiness_write(struct cgroup *cgrp, struct cftype *cft,
3654 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
3655 struct mem_cgroup *parent;
3660 if (cgrp->parent == NULL)
3663 parent = mem_cgroup_from_cont(cgrp->parent);
3667 /* If under hierarchy, only empty-root can set this value */
3668 if ((parent->use_hierarchy) ||
3669 (memcg->use_hierarchy && !list_empty(&cgrp->children))) {
3674 spin_lock(&memcg->reclaim_param_lock);
3675 memcg->swappiness = val;
3676 spin_unlock(&memcg->reclaim_param_lock);
3683 static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap)
3685 struct mem_cgroup_threshold_ary *t;
3691 t = rcu_dereference(memcg->thresholds.primary);
3693 t = rcu_dereference(memcg->memsw_thresholds.primary);
3698 usage = mem_cgroup_usage(memcg, swap);
3701 * current_threshold points to threshold just below usage.
3702 * If it's not true, a threshold was crossed after last
3703 * call of __mem_cgroup_threshold().
3705 i = t->current_threshold;
3708 * Iterate backward over array of thresholds starting from
3709 * current_threshold and check if a threshold is crossed.
3710 * If none of thresholds below usage is crossed, we read
3711 * only one element of the array here.
3713 for (; i >= 0 && unlikely(t->entries[i].threshold > usage); i--)
3714 eventfd_signal(t->entries[i].eventfd, 1);
3716 /* i = current_threshold + 1 */
3720 * Iterate forward over array of thresholds starting from
3721 * current_threshold+1 and check if a threshold is crossed.
3722 * If none of thresholds above usage is crossed, we read
3723 * only one element of the array here.
3725 for (; i < t->size && unlikely(t->entries[i].threshold <= usage); i++)
3726 eventfd_signal(t->entries[i].eventfd, 1);
3728 /* Update current_threshold */
3729 t->current_threshold = i - 1;
3734 static void mem_cgroup_threshold(struct mem_cgroup *memcg)
3737 __mem_cgroup_threshold(memcg, false);
3738 if (do_swap_account)
3739 __mem_cgroup_threshold(memcg, true);
3741 memcg = parent_mem_cgroup(memcg);
3745 static int compare_thresholds(const void *a, const void *b)
3747 const struct mem_cgroup_threshold *_a = a;
3748 const struct mem_cgroup_threshold *_b = b;
3750 return _a->threshold - _b->threshold;
3753 static int mem_cgroup_oom_notify_cb(struct mem_cgroup *mem)
3755 struct mem_cgroup_eventfd_list *ev;
3757 list_for_each_entry(ev, &mem->oom_notify, list)
3758 eventfd_signal(ev->eventfd, 1);
3762 static void mem_cgroup_oom_notify(struct mem_cgroup *mem)
3764 struct mem_cgroup *iter;
3766 for_each_mem_cgroup_tree(iter, mem)
3767 mem_cgroup_oom_notify_cb(iter);
3770 static int mem_cgroup_usage_register_event(struct cgroup *cgrp,
3771 struct cftype *cft, struct eventfd_ctx *eventfd, const char *args)
3773 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
3774 struct mem_cgroup_thresholds *thresholds;
3775 struct mem_cgroup_threshold_ary *new;
3776 int type = MEMFILE_TYPE(cft->private);
3777 u64 threshold, usage;
3780 ret = res_counter_memparse_write_strategy(args, &threshold);
3784 mutex_lock(&memcg->thresholds_lock);
3787 thresholds = &memcg->thresholds;
3788 else if (type == _MEMSWAP)
3789 thresholds = &memcg->memsw_thresholds;
3793 usage = mem_cgroup_usage(memcg, type == _MEMSWAP);
3795 /* Check if a threshold crossed before adding a new one */
3796 if (thresholds->primary)
3797 __mem_cgroup_threshold(memcg, type == _MEMSWAP);
3799 size = thresholds->primary ? thresholds->primary->size + 1 : 1;
3801 /* Allocate memory for new array of thresholds */
3802 new = kmalloc(sizeof(*new) + size * sizeof(struct mem_cgroup_threshold),
3810 /* Copy thresholds (if any) to new array */
3811 if (thresholds->primary) {
3812 memcpy(new->entries, thresholds->primary->entries, (size - 1) *
3813 sizeof(struct mem_cgroup_threshold));
3816 /* Add new threshold */
3817 new->entries[size - 1].eventfd = eventfd;
3818 new->entries[size - 1].threshold = threshold;
3820 /* Sort thresholds. Registering of new threshold isn't time-critical */
3821 sort(new->entries, size, sizeof(struct mem_cgroup_threshold),
3822 compare_thresholds, NULL);
3824 /* Find current threshold */
3825 new->current_threshold = -1;
3826 for (i = 0; i < size; i++) {
3827 if (new->entries[i].threshold < usage) {
3829 * new->current_threshold will not be used until
3830 * rcu_assign_pointer(), so it's safe to increment
3833 ++new->current_threshold;
3837 /* Free old spare buffer and save old primary buffer as spare */
3838 kfree(thresholds->spare);
3839 thresholds->spare = thresholds->primary;
3841 rcu_assign_pointer(thresholds->primary, new);
3843 /* To be sure that nobody uses thresholds */
3847 mutex_unlock(&memcg->thresholds_lock);
3852 static void mem_cgroup_usage_unregister_event(struct cgroup *cgrp,
3853 struct cftype *cft, struct eventfd_ctx *eventfd)
3855 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
3856 struct mem_cgroup_thresholds *thresholds;
3857 struct mem_cgroup_threshold_ary *new;
3858 int type = MEMFILE_TYPE(cft->private);
3862 mutex_lock(&memcg->thresholds_lock);
3864 thresholds = &memcg->thresholds;
3865 else if (type == _MEMSWAP)
3866 thresholds = &memcg->memsw_thresholds;
3871 * Something went wrong if we trying to unregister a threshold
3872 * if we don't have thresholds
3874 BUG_ON(!thresholds);
3876 usage = mem_cgroup_usage(memcg, type == _MEMSWAP);
3878 /* Check if a threshold crossed before removing */
3879 __mem_cgroup_threshold(memcg, type == _MEMSWAP);
3881 /* Calculate new number of threshold */
3883 for (i = 0; i < thresholds->primary->size; i++) {
3884 if (thresholds->primary->entries[i].eventfd != eventfd)
3888 new = thresholds->spare;
3890 /* Set thresholds array to NULL if we don't have thresholds */
3899 /* Copy thresholds and find current threshold */
3900 new->current_threshold = -1;
3901 for (i = 0, j = 0; i < thresholds->primary->size; i++) {
3902 if (thresholds->primary->entries[i].eventfd == eventfd)
3905 new->entries[j] = thresholds->primary->entries[i];
3906 if (new->entries[j].threshold < usage) {
3908 * new->current_threshold will not be used
3909 * until rcu_assign_pointer(), so it's safe to increment
3912 ++new->current_threshold;
3918 /* Swap primary and spare array */
3919 thresholds->spare = thresholds->primary;
3920 rcu_assign_pointer(thresholds->primary, new);
3922 /* To be sure that nobody uses thresholds */
3925 mutex_unlock(&memcg->thresholds_lock);
3928 static int mem_cgroup_oom_register_event(struct cgroup *cgrp,
3929 struct cftype *cft, struct eventfd_ctx *eventfd, const char *args)
3931 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
3932 struct mem_cgroup_eventfd_list *event;
3933 int type = MEMFILE_TYPE(cft->private);
3935 BUG_ON(type != _OOM_TYPE);
3936 event = kmalloc(sizeof(*event), GFP_KERNEL);
3940 mutex_lock(&memcg_oom_mutex);
3942 event->eventfd = eventfd;
3943 list_add(&event->list, &memcg->oom_notify);
3945 /* already in OOM ? */
3946 if (atomic_read(&memcg->oom_lock))
3947 eventfd_signal(eventfd, 1);
3948 mutex_unlock(&memcg_oom_mutex);
3953 static void mem_cgroup_oom_unregister_event(struct cgroup *cgrp,
3954 struct cftype *cft, struct eventfd_ctx *eventfd)
3956 struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp);
3957 struct mem_cgroup_eventfd_list *ev, *tmp;
3958 int type = MEMFILE_TYPE(cft->private);
3960 BUG_ON(type != _OOM_TYPE);
3962 mutex_lock(&memcg_oom_mutex);
3964 list_for_each_entry_safe(ev, tmp, &mem->oom_notify, list) {
3965 if (ev->eventfd == eventfd) {
3966 list_del(&ev->list);
3971 mutex_unlock(&memcg_oom_mutex);
3974 static int mem_cgroup_oom_control_read(struct cgroup *cgrp,
3975 struct cftype *cft, struct cgroup_map_cb *cb)
3977 struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp);
3979 cb->fill(cb, "oom_kill_disable", mem->oom_kill_disable);
3981 if (atomic_read(&mem->oom_lock))
3982 cb->fill(cb, "under_oom", 1);
3984 cb->fill(cb, "under_oom", 0);
3988 static int mem_cgroup_oom_control_write(struct cgroup *cgrp,
3989 struct cftype *cft, u64 val)
3991 struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp);
3992 struct mem_cgroup *parent;
3994 /* cannot set to root cgroup and only 0 and 1 are allowed */
3995 if (!cgrp->parent || !((val == 0) || (val == 1)))
3998 parent = mem_cgroup_from_cont(cgrp->parent);
4001 /* oom-kill-disable is a flag for subhierarchy. */
4002 if ((parent->use_hierarchy) ||
4003 (mem->use_hierarchy && !list_empty(&cgrp->children))) {
4007 mem->oom_kill_disable = val;
4009 memcg_oom_recover(mem);
4014 static struct cftype mem_cgroup_files[] = {
4016 .name = "usage_in_bytes",
4017 .private = MEMFILE_PRIVATE(_MEM, RES_USAGE),
4018 .read_u64 = mem_cgroup_read,
4019 .register_event = mem_cgroup_usage_register_event,
4020 .unregister_event = mem_cgroup_usage_unregister_event,
4023 .name = "max_usage_in_bytes",
4024 .private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE),
4025 .trigger = mem_cgroup_reset,
4026 .read_u64 = mem_cgroup_read,
4029 .name = "limit_in_bytes",
4030 .private = MEMFILE_PRIVATE(_MEM, RES_LIMIT),
4031 .write_string = mem_cgroup_write,
4032 .read_u64 = mem_cgroup_read,
4035 .name = "soft_limit_in_bytes",
4036 .private = MEMFILE_PRIVATE(_MEM, RES_SOFT_LIMIT),
4037 .write_string = mem_cgroup_write,
4038 .read_u64 = mem_cgroup_read,
4042 .private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT),
4043 .trigger = mem_cgroup_reset,
4044 .read_u64 = mem_cgroup_read,
4048 .read_map = mem_control_stat_show,
4051 .name = "force_empty",
4052 .trigger = mem_cgroup_force_empty_write,
4055 .name = "use_hierarchy",
4056 .write_u64 = mem_cgroup_hierarchy_write,
4057 .read_u64 = mem_cgroup_hierarchy_read,
4060 .name = "swappiness",
4061 .read_u64 = mem_cgroup_swappiness_read,
4062 .write_u64 = mem_cgroup_swappiness_write,
4065 .name = "move_charge_at_immigrate",
4066 .read_u64 = mem_cgroup_move_charge_read,
4067 .write_u64 = mem_cgroup_move_charge_write,
4070 .name = "oom_control",
4071 .read_map = mem_cgroup_oom_control_read,
4072 .write_u64 = mem_cgroup_oom_control_write,
4073 .register_event = mem_cgroup_oom_register_event,
4074 .unregister_event = mem_cgroup_oom_unregister_event,
4075 .private = MEMFILE_PRIVATE(_OOM_TYPE, OOM_CONTROL),
4079 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
4080 static struct cftype memsw_cgroup_files[] = {
4082 .name = "memsw.usage_in_bytes",
4083 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE),
4084 .read_u64 = mem_cgroup_read,
4085 .register_event = mem_cgroup_usage_register_event,
4086 .unregister_event = mem_cgroup_usage_unregister_event,
4089 .name = "memsw.max_usage_in_bytes",
4090 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE),
4091 .trigger = mem_cgroup_reset,
4092 .read_u64 = mem_cgroup_read,
4095 .name = "memsw.limit_in_bytes",
4096 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT),
4097 .write_string = mem_cgroup_write,
4098 .read_u64 = mem_cgroup_read,
4101 .name = "memsw.failcnt",
4102 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT),
4103 .trigger = mem_cgroup_reset,
4104 .read_u64 = mem_cgroup_read,
4108 static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss)
4110 if (!do_swap_account)
4112 return cgroup_add_files(cont, ss, memsw_cgroup_files,
4113 ARRAY_SIZE(memsw_cgroup_files));
4116 static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss)
4122 static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
4124 struct mem_cgroup_per_node *pn;
4125 struct mem_cgroup_per_zone *mz;
4127 int zone, tmp = node;
4129 * This routine is called against possible nodes.
4130 * But it's BUG to call kmalloc() against offline node.
4132 * TODO: this routine can waste much memory for nodes which will
4133 * never be onlined. It's better to use memory hotplug callback
4136 if (!node_state(node, N_NORMAL_MEMORY))
4138 pn = kmalloc_node(sizeof(*pn), GFP_KERNEL, tmp);
4142 mem->info.nodeinfo[node] = pn;
4143 memset(pn, 0, sizeof(*pn));
4145 for (zone = 0; zone < MAX_NR_ZONES; zone++) {
4146 mz = &pn->zoneinfo[zone];
4148 INIT_LIST_HEAD(&mz->lists[l]);
4149 mz->usage_in_excess = 0;
4150 mz->on_tree = false;
4156 static void free_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
4158 kfree(mem->info.nodeinfo[node]);
4161 static struct mem_cgroup *mem_cgroup_alloc(void)
4163 struct mem_cgroup *mem;
4164 int size = sizeof(struct mem_cgroup);
4166 /* Can be very big if MAX_NUMNODES is very big */
4167 if (size < PAGE_SIZE)
4168 mem = kmalloc(size, GFP_KERNEL);
4170 mem = vmalloc(size);
4175 memset(mem, 0, size);
4176 mem->stat = alloc_percpu(struct mem_cgroup_stat_cpu);
4178 if (size < PAGE_SIZE)
4184 spin_lock_init(&mem->pcp_counter_lock);
4189 * At destroying mem_cgroup, references from swap_cgroup can remain.
4190 * (scanning all at force_empty is too costly...)
4192 * Instead of clearing all references at force_empty, we remember
4193 * the number of reference from swap_cgroup and free mem_cgroup when
4194 * it goes down to 0.
4196 * Removal of cgroup itself succeeds regardless of refs from swap.
4199 static void __mem_cgroup_free(struct mem_cgroup *mem)
4203 mem_cgroup_remove_from_trees(mem);
4204 free_css_id(&mem_cgroup_subsys, &mem->css);
4206 for_each_node_state(node, N_POSSIBLE)
4207 free_mem_cgroup_per_zone_info(mem, node);
4209 free_percpu(mem->stat);
4210 if (sizeof(struct mem_cgroup) < PAGE_SIZE)
4216 static void mem_cgroup_get(struct mem_cgroup *mem)
4218 atomic_inc(&mem->refcnt);
4221 static void __mem_cgroup_put(struct mem_cgroup *mem, int count)
4223 if (atomic_sub_and_test(count, &mem->refcnt)) {
4224 struct mem_cgroup *parent = parent_mem_cgroup(mem);
4225 __mem_cgroup_free(mem);
4227 mem_cgroup_put(parent);
4231 static void mem_cgroup_put(struct mem_cgroup *mem)
4233 __mem_cgroup_put(mem, 1);
4237 * Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled.
4239 static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem)
4241 if (!mem->res.parent)
4243 return mem_cgroup_from_res_counter(mem->res.parent, res);
4246 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
4247 static void __init enable_swap_cgroup(void)
4249 if (!mem_cgroup_disabled() && really_do_swap_account)
4250 do_swap_account = 1;
4253 static void __init enable_swap_cgroup(void)
4258 static int mem_cgroup_soft_limit_tree_init(void)
4260 struct mem_cgroup_tree_per_node *rtpn;
4261 struct mem_cgroup_tree_per_zone *rtpz;
4262 int tmp, node, zone;
4264 for_each_node_state(node, N_POSSIBLE) {
4266 if (!node_state(node, N_NORMAL_MEMORY))
4268 rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL, tmp);
4272 soft_limit_tree.rb_tree_per_node[node] = rtpn;
4274 for (zone = 0; zone < MAX_NR_ZONES; zone++) {
4275 rtpz = &rtpn->rb_tree_per_zone[zone];
4276 rtpz->rb_root = RB_ROOT;
4277 spin_lock_init(&rtpz->lock);
4283 static struct cgroup_subsys_state * __ref
4284 mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
4286 struct mem_cgroup *mem, *parent;
4287 long error = -ENOMEM;
4290 mem = mem_cgroup_alloc();
4292 return ERR_PTR(error);
4294 for_each_node_state(node, N_POSSIBLE)
4295 if (alloc_mem_cgroup_per_zone_info(mem, node))
4299 if (cont->parent == NULL) {
4301 enable_swap_cgroup();
4303 root_mem_cgroup = mem;
4304 if (mem_cgroup_soft_limit_tree_init())
4306 for_each_possible_cpu(cpu) {
4307 struct memcg_stock_pcp *stock =
4308 &per_cpu(memcg_stock, cpu);
4309 INIT_WORK(&stock->work, drain_local_stock);
4311 hotcpu_notifier(memcg_cpu_hotplug_callback, 0);
4313 parent = mem_cgroup_from_cont(cont->parent);
4314 mem->use_hierarchy = parent->use_hierarchy;
4315 mem->oom_kill_disable = parent->oom_kill_disable;
4318 if (parent && parent->use_hierarchy) {
4319 res_counter_init(&mem->res, &parent->res);
4320 res_counter_init(&mem->memsw, &parent->memsw);
4322 * We increment refcnt of the parent to ensure that we can
4323 * safely access it on res_counter_charge/uncharge.
4324 * This refcnt will be decremented when freeing this
4325 * mem_cgroup(see mem_cgroup_put).
4327 mem_cgroup_get(parent);
4329 res_counter_init(&mem->res, NULL);
4330 res_counter_init(&mem->memsw, NULL);
4332 mem->last_scanned_child = 0;
4333 spin_lock_init(&mem->reclaim_param_lock);
4334 INIT_LIST_HEAD(&mem->oom_notify);
4337 mem->swappiness = get_swappiness(parent);
4338 atomic_set(&mem->refcnt, 1);
4339 mem->move_charge_at_immigrate = 0;
4340 mutex_init(&mem->thresholds_lock);
4343 __mem_cgroup_free(mem);
4344 root_mem_cgroup = NULL;
4345 return ERR_PTR(error);
4348 static int mem_cgroup_pre_destroy(struct cgroup_subsys *ss,
4349 struct cgroup *cont)
4351 struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
4353 return mem_cgroup_force_empty(mem, false);
4356 static void mem_cgroup_destroy(struct cgroup_subsys *ss,
4357 struct cgroup *cont)
4359 struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
4361 mem_cgroup_put(mem);
4364 static int mem_cgroup_populate(struct cgroup_subsys *ss,
4365 struct cgroup *cont)
4369 ret = cgroup_add_files(cont, ss, mem_cgroup_files,
4370 ARRAY_SIZE(mem_cgroup_files));
4373 ret = register_memsw_files(cont, ss);
4378 /* Handlers for move charge at task migration. */
4379 #define PRECHARGE_COUNT_AT_ONCE 256
4380 static int mem_cgroup_do_precharge(unsigned long count)
4383 int batch_count = PRECHARGE_COUNT_AT_ONCE;
4384 struct mem_cgroup *mem = mc.to;
4386 if (mem_cgroup_is_root(mem)) {
4387 mc.precharge += count;
4388 /* we don't need css_get for root */
4391 /* try to charge at once */
4393 struct res_counter *dummy;
4395 * "mem" cannot be under rmdir() because we've already checked
4396 * by cgroup_lock_live_cgroup() that it is not removed and we
4397 * are still under the same cgroup_mutex. So we can postpone
4400 if (res_counter_charge(&mem->res, PAGE_SIZE * count, &dummy))
4402 if (do_swap_account && res_counter_charge(&mem->memsw,
4403 PAGE_SIZE * count, &dummy)) {
4404 res_counter_uncharge(&mem->res, PAGE_SIZE * count);
4407 mc.precharge += count;
4411 /* fall back to one by one charge */
4413 if (signal_pending(current)) {
4417 if (!batch_count--) {
4418 batch_count = PRECHARGE_COUNT_AT_ONCE;
4421 ret = __mem_cgroup_try_charge(NULL, GFP_KERNEL, &mem, false);
4423 /* mem_cgroup_clear_mc() will do uncharge later */
4431 * is_target_pte_for_mc - check a pte whether it is valid for move charge
4432 * @vma: the vma the pte to be checked belongs
4433 * @addr: the address corresponding to the pte to be checked
4434 * @ptent: the pte to be checked
4435 * @target: the pointer the target page or swap ent will be stored(can be NULL)
4438 * 0(MC_TARGET_NONE): if the pte is not a target for move charge.
4439 * 1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for
4440 * move charge. if @target is not NULL, the page is stored in target->page
4441 * with extra refcnt got(Callers should handle it).
4442 * 2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a
4443 * target for charge migration. if @target is not NULL, the entry is stored
4446 * Called with pte lock held.
4453 enum mc_target_type {
4454 MC_TARGET_NONE, /* not used */
4459 static struct page *mc_handle_present_pte(struct vm_area_struct *vma,
4460 unsigned long addr, pte_t ptent)
4462 struct page *page = vm_normal_page(vma, addr, ptent);
4464 if (!page || !page_mapped(page))
4466 if (PageAnon(page)) {
4467 /* we don't move shared anon */
4468 if (!move_anon() || page_mapcount(page) > 2)
4470 } else if (!move_file())
4471 /* we ignore mapcount for file pages */
4473 if (!get_page_unless_zero(page))
4479 static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
4480 unsigned long addr, pte_t ptent, swp_entry_t *entry)
4483 struct page *page = NULL;
4484 swp_entry_t ent = pte_to_swp_entry(ptent);
4486 if (!move_anon() || non_swap_entry(ent))
4488 usage_count = mem_cgroup_count_swap_user(ent, &page);
4489 if (usage_count > 1) { /* we don't move shared anon */
4494 if (do_swap_account)
4495 entry->val = ent.val;
4500 static struct page *mc_handle_file_pte(struct vm_area_struct *vma,
4501 unsigned long addr, pte_t ptent, swp_entry_t *entry)
4503 struct page *page = NULL;
4504 struct inode *inode;
4505 struct address_space *mapping;
4508 if (!vma->vm_file) /* anonymous vma */
4513 inode = vma->vm_file->f_path.dentry->d_inode;
4514 mapping = vma->vm_file->f_mapping;
4515 if (pte_none(ptent))
4516 pgoff = linear_page_index(vma, addr);
4517 else /* pte_file(ptent) is true */
4518 pgoff = pte_to_pgoff(ptent);
4520 /* page is moved even if it's not RSS of this task(page-faulted). */
4521 if (!mapping_cap_swap_backed(mapping)) { /* normal file */
4522 page = find_get_page(mapping, pgoff);
4523 } else { /* shmem/tmpfs file. we should take account of swap too. */
4525 mem_cgroup_get_shmem_target(inode, pgoff, &page, &ent);
4526 if (do_swap_account)
4527 entry->val = ent.val;
4533 static int is_target_pte_for_mc(struct vm_area_struct *vma,
4534 unsigned long addr, pte_t ptent, union mc_target *target)
4536 struct page *page = NULL;
4537 struct page_cgroup *pc;
4539 swp_entry_t ent = { .val = 0 };
4541 if (pte_present(ptent))
4542 page = mc_handle_present_pte(vma, addr, ptent);
4543 else if (is_swap_pte(ptent))
4544 page = mc_handle_swap_pte(vma, addr, ptent, &ent);
4545 else if (pte_none(ptent) || pte_file(ptent))
4546 page = mc_handle_file_pte(vma, addr, ptent, &ent);
4548 if (!page && !ent.val)
4551 pc = lookup_page_cgroup(page);
4553 * Do only loose check w/o page_cgroup lock.
4554 * mem_cgroup_move_account() checks the pc is valid or not under
4557 if (PageCgroupUsed(pc) && pc->mem_cgroup == mc.from) {
4558 ret = MC_TARGET_PAGE;
4560 target->page = page;
4562 if (!ret || !target)
4565 /* There is a swap entry and a page doesn't exist or isn't charged */
4566 if (ent.val && !ret &&
4567 css_id(&mc.from->css) == lookup_swap_cgroup(ent)) {
4568 ret = MC_TARGET_SWAP;
4575 static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd,
4576 unsigned long addr, unsigned long end,
4577 struct mm_walk *walk)
4579 struct vm_area_struct *vma = walk->private;
4583 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
4584 for (; addr != end; pte++, addr += PAGE_SIZE)
4585 if (is_target_pte_for_mc(vma, addr, *pte, NULL))
4586 mc.precharge++; /* increment precharge temporarily */
4587 pte_unmap_unlock(pte - 1, ptl);
4593 static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm)
4595 unsigned long precharge;
4596 struct vm_area_struct *vma;
4598 down_read(&mm->mmap_sem);
4599 for (vma = mm->mmap; vma; vma = vma->vm_next) {
4600 struct mm_walk mem_cgroup_count_precharge_walk = {
4601 .pmd_entry = mem_cgroup_count_precharge_pte_range,
4605 if (is_vm_hugetlb_page(vma))
4607 walk_page_range(vma->vm_start, vma->vm_end,
4608 &mem_cgroup_count_precharge_walk);
4610 up_read(&mm->mmap_sem);
4612 precharge = mc.precharge;
4618 static int mem_cgroup_precharge_mc(struct mm_struct *mm)
4620 return mem_cgroup_do_precharge(mem_cgroup_count_precharge(mm));
4623 static void mem_cgroup_clear_mc(void)
4625 struct mem_cgroup *from = mc.from;
4626 struct mem_cgroup *to = mc.to;
4628 /* we must uncharge all the leftover precharges from mc.to */
4630 __mem_cgroup_cancel_charge(mc.to, mc.precharge);
4634 * we didn't uncharge from mc.from at mem_cgroup_move_account(), so
4635 * we must uncharge here.
4637 if (mc.moved_charge) {
4638 __mem_cgroup_cancel_charge(mc.from, mc.moved_charge);
4639 mc.moved_charge = 0;
4641 /* we must fixup refcnts and charges */
4642 if (mc.moved_swap) {
4643 /* uncharge swap account from the old cgroup */
4644 if (!mem_cgroup_is_root(mc.from))
4645 res_counter_uncharge(&mc.from->memsw,
4646 PAGE_SIZE * mc.moved_swap);
4647 __mem_cgroup_put(mc.from, mc.moved_swap);
4649 if (!mem_cgroup_is_root(mc.to)) {
4651 * we charged both to->res and to->memsw, so we should
4654 res_counter_uncharge(&mc.to->res,
4655 PAGE_SIZE * mc.moved_swap);
4657 /* we've already done mem_cgroup_get(mc.to) */
4661 spin_lock(&mc.lock);
4664 mc.moving_task = NULL;
4665 spin_unlock(&mc.lock);
4666 mem_cgroup_end_move(from);
4667 memcg_oom_recover(from);
4668 memcg_oom_recover(to);
4669 wake_up_all(&mc.waitq);
4672 static int mem_cgroup_can_attach(struct cgroup_subsys *ss,
4673 struct cgroup *cgroup,
4674 struct task_struct *p,
4678 struct mem_cgroup *mem = mem_cgroup_from_cont(cgroup);
4680 if (mem->move_charge_at_immigrate) {
4681 struct mm_struct *mm;
4682 struct mem_cgroup *from = mem_cgroup_from_task(p);
4684 VM_BUG_ON(from == mem);
4686 mm = get_task_mm(p);
4689 /* We move charges only when we move a owner of the mm */
4690 if (mm->owner == p) {
4693 VM_BUG_ON(mc.precharge);
4694 VM_BUG_ON(mc.moved_charge);
4695 VM_BUG_ON(mc.moved_swap);
4696 VM_BUG_ON(mc.moving_task);
4697 mem_cgroup_start_move(from);
4698 spin_lock(&mc.lock);
4702 mc.moved_charge = 0;
4704 mc.moving_task = current;
4705 spin_unlock(&mc.lock);
4707 ret = mem_cgroup_precharge_mc(mm);
4709 mem_cgroup_clear_mc();
4716 static void mem_cgroup_cancel_attach(struct cgroup_subsys *ss,
4717 struct cgroup *cgroup,
4718 struct task_struct *p,
4721 mem_cgroup_clear_mc();
4724 static int mem_cgroup_move_charge_pte_range(pmd_t *pmd,
4725 unsigned long addr, unsigned long end,
4726 struct mm_walk *walk)
4729 struct vm_area_struct *vma = walk->private;
4734 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
4735 for (; addr != end; addr += PAGE_SIZE) {
4736 pte_t ptent = *(pte++);
4737 union mc_target target;
4740 struct page_cgroup *pc;
4746 type = is_target_pte_for_mc(vma, addr, ptent, &target);
4748 case MC_TARGET_PAGE:
4750 if (isolate_lru_page(page))
4752 pc = lookup_page_cgroup(page);
4753 if (!mem_cgroup_move_account(pc,
4754 mc.from, mc.to, false)) {
4756 /* we uncharge from mc.from later. */
4759 putback_lru_page(page);
4760 put: /* is_target_pte_for_mc() gets the page */
4763 case MC_TARGET_SWAP:
4765 if (!mem_cgroup_move_swap_account(ent,
4766 mc.from, mc.to, false)) {
4768 /* we fixup refcnts and charges later. */
4776 pte_unmap_unlock(pte - 1, ptl);
4781 * We have consumed all precharges we got in can_attach().
4782 * We try charge one by one, but don't do any additional
4783 * charges to mc.to if we have failed in charge once in attach()
4786 ret = mem_cgroup_do_precharge(1);
4794 static void mem_cgroup_move_charge(struct mm_struct *mm)
4796 struct vm_area_struct *vma;
4798 lru_add_drain_all();
4799 down_read(&mm->mmap_sem);
4800 for (vma = mm->mmap; vma; vma = vma->vm_next) {
4802 struct mm_walk mem_cgroup_move_charge_walk = {
4803 .pmd_entry = mem_cgroup_move_charge_pte_range,
4807 if (is_vm_hugetlb_page(vma))
4809 ret = walk_page_range(vma->vm_start, vma->vm_end,
4810 &mem_cgroup_move_charge_walk);
4813 * means we have consumed all precharges and failed in
4814 * doing additional charge. Just abandon here.
4818 up_read(&mm->mmap_sem);
4821 static void mem_cgroup_move_task(struct cgroup_subsys *ss,
4822 struct cgroup *cont,
4823 struct cgroup *old_cont,
4824 struct task_struct *p,
4827 struct mm_struct *mm;
4830 /* no need to move charge */
4833 mm = get_task_mm(p);
4835 mem_cgroup_move_charge(mm);
4838 mem_cgroup_clear_mc();
4840 #else /* !CONFIG_MMU */
4841 static int mem_cgroup_can_attach(struct cgroup_subsys *ss,
4842 struct cgroup *cgroup,
4843 struct task_struct *p,
4848 static void mem_cgroup_cancel_attach(struct cgroup_subsys *ss,
4849 struct cgroup *cgroup,
4850 struct task_struct *p,
4854 static void mem_cgroup_move_task(struct cgroup_subsys *ss,
4855 struct cgroup *cont,
4856 struct cgroup *old_cont,
4857 struct task_struct *p,
4863 struct cgroup_subsys mem_cgroup_subsys = {
4865 .subsys_id = mem_cgroup_subsys_id,
4866 .create = mem_cgroup_create,
4867 .pre_destroy = mem_cgroup_pre_destroy,
4868 .destroy = mem_cgroup_destroy,
4869 .populate = mem_cgroup_populate,
4870 .can_attach = mem_cgroup_can_attach,
4871 .cancel_attach = mem_cgroup_cancel_attach,
4872 .attach = mem_cgroup_move_task,
4877 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
4879 static int __init disable_swap_account(char *s)
4881 really_do_swap_account = 0;
4884 __setup("noswapaccount", disable_swap_account);