1 /* memcontrol.c - Memory Controller
3 * Copyright IBM Corporation, 2007
4 * Author Balbir Singh <balbir@linux.vnet.ibm.com>
6 * Copyright 2007 OpenVZ SWsoft Inc
7 * Author: Pavel Emelianov <xemul@openvz.org>
10 * Copyright (C) 2009 Nokia Corporation
11 * Author: Kirill A. Shutemov
13 * This program is free software; you can redistribute it and/or modify
14 * it under the terms of the GNU General Public License as published by
15 * the Free Software Foundation; either version 2 of the License, or
16 * (at your option) any later version.
18 * This program is distributed in the hope that it will be useful,
19 * but WITHOUT ANY WARRANTY; without even the implied warranty of
20 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
21 * GNU General Public License for more details.
24 #include <linux/res_counter.h>
25 #include <linux/memcontrol.h>
26 #include <linux/cgroup.h>
28 #include <linux/hugetlb.h>
29 #include <linux/pagemap.h>
30 #include <linux/smp.h>
31 #include <linux/page-flags.h>
32 #include <linux/backing-dev.h>
33 #include <linux/bit_spinlock.h>
34 #include <linux/rcupdate.h>
35 #include <linux/limits.h>
36 #include <linux/mutex.h>
37 #include <linux/rbtree.h>
38 #include <linux/slab.h>
39 #include <linux/swap.h>
40 #include <linux/swapops.h>
41 #include <linux/spinlock.h>
42 #include <linux/eventfd.h>
43 #include <linux/sort.h>
45 #include <linux/seq_file.h>
46 #include <linux/vmalloc.h>
47 #include <linux/mm_inline.h>
48 #include <linux/page_cgroup.h>
49 #include <linux/cpu.h>
50 #include <linux/oom.h>
53 #include <asm/uaccess.h>
55 #include <trace/events/vmscan.h>
57 struct cgroup_subsys mem_cgroup_subsys __read_mostly;
58 #define MEM_CGROUP_RECLAIM_RETRIES 5
59 struct mem_cgroup *root_mem_cgroup __read_mostly;
61 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
62 /* Turned on only when memory cgroup is enabled && really_do_swap_account = 1 */
63 int do_swap_account __read_mostly;
65 /* for remember boot option*/
66 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP_ENABLED
67 static int really_do_swap_account __initdata = 1;
69 static int really_do_swap_account __initdata = 0;
73 #define do_swap_account (0)
77 * Per memcg event counter is incremented at every pagein/pageout. This counter
78 * is used for trigger some periodic events. This is straightforward and better
79 * than using jiffies etc. to handle periodic memcg event.
81 * These values will be used as !((event) & ((1 <<(thresh)) - 1))
83 #define THRESHOLDS_EVENTS_THRESH (7) /* once in 128 */
84 #define SOFTLIMIT_EVENTS_THRESH (10) /* once in 1024 */
87 * Statistics for memory cgroup.
89 enum mem_cgroup_stat_index {
91 * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss.
93 MEM_CGROUP_STAT_CACHE, /* # of pages charged as cache */
94 MEM_CGROUP_STAT_RSS, /* # of pages charged as anon rss */
95 MEM_CGROUP_STAT_FILE_MAPPED, /* # of pages charged as file rss */
96 MEM_CGROUP_STAT_PGPGIN_COUNT, /* # of pages paged in */
97 MEM_CGROUP_STAT_PGPGOUT_COUNT, /* # of pages paged out */
98 MEM_CGROUP_STAT_SWAPOUT, /* # of pages, swapped out */
99 MEM_CGROUP_STAT_DATA, /* end of data requires synchronization */
100 /* incremented at every pagein/pageout */
101 MEM_CGROUP_EVENTS = MEM_CGROUP_STAT_DATA,
102 MEM_CGROUP_ON_MOVE, /* someone is moving account between groups */
104 MEM_CGROUP_STAT_NSTATS,
107 struct mem_cgroup_stat_cpu {
108 s64 count[MEM_CGROUP_STAT_NSTATS];
112 * per-zone information in memory controller.
114 struct mem_cgroup_per_zone {
116 * spin_lock to protect the per cgroup LRU
118 struct list_head lists[NR_LRU_LISTS];
119 unsigned long count[NR_LRU_LISTS];
121 struct zone_reclaim_stat reclaim_stat;
122 struct rb_node tree_node; /* RB tree node */
123 unsigned long long usage_in_excess;/* Set to the value by which */
124 /* the soft limit is exceeded*/
126 struct mem_cgroup *mem; /* Back pointer, we cannot */
127 /* use container_of */
129 /* Macro for accessing counter */
130 #define MEM_CGROUP_ZSTAT(mz, idx) ((mz)->count[(idx)])
132 struct mem_cgroup_per_node {
133 struct mem_cgroup_per_zone zoneinfo[MAX_NR_ZONES];
136 struct mem_cgroup_lru_info {
137 struct mem_cgroup_per_node *nodeinfo[MAX_NUMNODES];
141 * Cgroups above their limits are maintained in a RB-Tree, independent of
142 * their hierarchy representation
145 struct mem_cgroup_tree_per_zone {
146 struct rb_root rb_root;
150 struct mem_cgroup_tree_per_node {
151 struct mem_cgroup_tree_per_zone rb_tree_per_zone[MAX_NR_ZONES];
154 struct mem_cgroup_tree {
155 struct mem_cgroup_tree_per_node *rb_tree_per_node[MAX_NUMNODES];
158 static struct mem_cgroup_tree soft_limit_tree __read_mostly;
160 struct mem_cgroup_threshold {
161 struct eventfd_ctx *eventfd;
166 struct mem_cgroup_threshold_ary {
167 /* An array index points to threshold just below usage. */
168 int current_threshold;
169 /* Size of entries[] */
171 /* Array of thresholds */
172 struct mem_cgroup_threshold entries[0];
175 struct mem_cgroup_thresholds {
176 /* Primary thresholds array */
177 struct mem_cgroup_threshold_ary *primary;
179 * Spare threshold array.
180 * This is needed to make mem_cgroup_unregister_event() "never fail".
181 * It must be able to store at least primary->size - 1 entries.
183 struct mem_cgroup_threshold_ary *spare;
187 struct mem_cgroup_eventfd_list {
188 struct list_head list;
189 struct eventfd_ctx *eventfd;
192 static void mem_cgroup_threshold(struct mem_cgroup *mem);
193 static void mem_cgroup_oom_notify(struct mem_cgroup *mem);
196 * The memory controller data structure. The memory controller controls both
197 * page cache and RSS per cgroup. We would eventually like to provide
198 * statistics based on the statistics developed by Rik Van Riel for clock-pro,
199 * to help the administrator determine what knobs to tune.
201 * TODO: Add a water mark for the memory controller. Reclaim will begin when
202 * we hit the water mark. May be even add a low water mark, such that
203 * no reclaim occurs from a cgroup at it's low water mark, this is
204 * a feature that will be implemented much later in the future.
207 struct cgroup_subsys_state css;
209 * the counter to account for memory usage
211 struct res_counter res;
213 * the counter to account for mem+swap usage.
215 struct res_counter memsw;
217 * Per cgroup active and inactive list, similar to the
218 * per zone LRU lists.
220 struct mem_cgroup_lru_info info;
222 * While reclaiming in a hierarchy, we cache the last child we
225 int last_scanned_child;
227 * Should the accounting and control be hierarchical, per subtree?
233 unsigned int swappiness;
234 /* OOM-Killer disable */
235 int oom_kill_disable;
237 /* set when res.limit == memsw.limit */
238 bool memsw_is_minimum;
240 /* protect arrays of thresholds */
241 struct mutex thresholds_lock;
243 /* thresholds for memory usage. RCU-protected */
244 struct mem_cgroup_thresholds thresholds;
246 /* thresholds for mem+swap usage. RCU-protected */
247 struct mem_cgroup_thresholds memsw_thresholds;
249 /* For oom notifier event fd */
250 struct list_head oom_notify;
253 * Should we move charges of a task when a task is moved into this
254 * mem_cgroup ? And what type of charges should we move ?
256 unsigned long move_charge_at_immigrate;
260 struct mem_cgroup_stat_cpu *stat;
262 * used when a cpu is offlined or other synchronizations
263 * See mem_cgroup_read_stat().
265 struct mem_cgroup_stat_cpu nocpu_base;
266 spinlock_t pcp_counter_lock;
269 /* Stuffs for move charges at task migration. */
271 * Types of charges to be moved. "move_charge_at_immitgrate" is treated as a
272 * left-shifted bitmap of these types.
275 MOVE_CHARGE_TYPE_ANON, /* private anonymous page and swap of it */
276 MOVE_CHARGE_TYPE_FILE, /* file page(including tmpfs) and swap of it */
280 /* "mc" and its members are protected by cgroup_mutex */
281 static struct move_charge_struct {
282 spinlock_t lock; /* for from, to */
283 struct mem_cgroup *from;
284 struct mem_cgroup *to;
285 unsigned long precharge;
286 unsigned long moved_charge;
287 unsigned long moved_swap;
288 struct task_struct *moving_task; /* a task moving charges */
289 wait_queue_head_t waitq; /* a waitq for other context */
291 .lock = __SPIN_LOCK_UNLOCKED(mc.lock),
292 .waitq = __WAIT_QUEUE_HEAD_INITIALIZER(mc.waitq),
295 static bool move_anon(void)
297 return test_bit(MOVE_CHARGE_TYPE_ANON,
298 &mc.to->move_charge_at_immigrate);
301 static bool move_file(void)
303 return test_bit(MOVE_CHARGE_TYPE_FILE,
304 &mc.to->move_charge_at_immigrate);
308 * Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft
309 * limit reclaim to prevent infinite loops, if they ever occur.
311 #define MEM_CGROUP_MAX_RECLAIM_LOOPS (100)
312 #define MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS (2)
315 MEM_CGROUP_CHARGE_TYPE_CACHE = 0,
316 MEM_CGROUP_CHARGE_TYPE_MAPPED,
317 MEM_CGROUP_CHARGE_TYPE_SHMEM, /* used by page migration of shmem */
318 MEM_CGROUP_CHARGE_TYPE_FORCE, /* used by force_empty */
319 MEM_CGROUP_CHARGE_TYPE_SWAPOUT, /* for accounting swapcache */
320 MEM_CGROUP_CHARGE_TYPE_DROP, /* a page was unused swap cache */
324 /* for encoding cft->private value on file */
327 #define _OOM_TYPE (2)
328 #define MEMFILE_PRIVATE(x, val) (((x) << 16) | (val))
329 #define MEMFILE_TYPE(val) (((val) >> 16) & 0xffff)
330 #define MEMFILE_ATTR(val) ((val) & 0xffff)
331 /* Used for OOM nofiier */
332 #define OOM_CONTROL (0)
335 * Reclaim flags for mem_cgroup_hierarchical_reclaim
337 #define MEM_CGROUP_RECLAIM_NOSWAP_BIT 0x0
338 #define MEM_CGROUP_RECLAIM_NOSWAP (1 << MEM_CGROUP_RECLAIM_NOSWAP_BIT)
339 #define MEM_CGROUP_RECLAIM_SHRINK_BIT 0x1
340 #define MEM_CGROUP_RECLAIM_SHRINK (1 << MEM_CGROUP_RECLAIM_SHRINK_BIT)
341 #define MEM_CGROUP_RECLAIM_SOFT_BIT 0x2
342 #define MEM_CGROUP_RECLAIM_SOFT (1 << MEM_CGROUP_RECLAIM_SOFT_BIT)
344 static void mem_cgroup_get(struct mem_cgroup *mem);
345 static void mem_cgroup_put(struct mem_cgroup *mem);
346 static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem);
347 static void drain_all_stock_async(void);
349 static struct mem_cgroup_per_zone *
350 mem_cgroup_zoneinfo(struct mem_cgroup *mem, int nid, int zid)
352 return &mem->info.nodeinfo[nid]->zoneinfo[zid];
355 struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *mem)
360 static struct mem_cgroup_per_zone *
361 page_cgroup_zoneinfo(struct mem_cgroup *mem, struct page *page)
363 int nid = page_to_nid(page);
364 int zid = page_zonenum(page);
366 return mem_cgroup_zoneinfo(mem, nid, zid);
369 static struct mem_cgroup_tree_per_zone *
370 soft_limit_tree_node_zone(int nid, int zid)
372 return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid];
375 static struct mem_cgroup_tree_per_zone *
376 soft_limit_tree_from_page(struct page *page)
378 int nid = page_to_nid(page);
379 int zid = page_zonenum(page);
381 return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid];
385 __mem_cgroup_insert_exceeded(struct mem_cgroup *mem,
386 struct mem_cgroup_per_zone *mz,
387 struct mem_cgroup_tree_per_zone *mctz,
388 unsigned long long new_usage_in_excess)
390 struct rb_node **p = &mctz->rb_root.rb_node;
391 struct rb_node *parent = NULL;
392 struct mem_cgroup_per_zone *mz_node;
397 mz->usage_in_excess = new_usage_in_excess;
398 if (!mz->usage_in_excess)
402 mz_node = rb_entry(parent, struct mem_cgroup_per_zone,
404 if (mz->usage_in_excess < mz_node->usage_in_excess)
407 * We can't avoid mem cgroups that are over their soft
408 * limit by the same amount
410 else if (mz->usage_in_excess >= mz_node->usage_in_excess)
413 rb_link_node(&mz->tree_node, parent, p);
414 rb_insert_color(&mz->tree_node, &mctz->rb_root);
419 __mem_cgroup_remove_exceeded(struct mem_cgroup *mem,
420 struct mem_cgroup_per_zone *mz,
421 struct mem_cgroup_tree_per_zone *mctz)
425 rb_erase(&mz->tree_node, &mctz->rb_root);
430 mem_cgroup_remove_exceeded(struct mem_cgroup *mem,
431 struct mem_cgroup_per_zone *mz,
432 struct mem_cgroup_tree_per_zone *mctz)
434 spin_lock(&mctz->lock);
435 __mem_cgroup_remove_exceeded(mem, mz, mctz);
436 spin_unlock(&mctz->lock);
440 static void mem_cgroup_update_tree(struct mem_cgroup *mem, struct page *page)
442 unsigned long long excess;
443 struct mem_cgroup_per_zone *mz;
444 struct mem_cgroup_tree_per_zone *mctz;
445 int nid = page_to_nid(page);
446 int zid = page_zonenum(page);
447 mctz = soft_limit_tree_from_page(page);
450 * Necessary to update all ancestors when hierarchy is used.
451 * because their event counter is not touched.
453 for (; mem; mem = parent_mem_cgroup(mem)) {
454 mz = mem_cgroup_zoneinfo(mem, nid, zid);
455 excess = res_counter_soft_limit_excess(&mem->res);
457 * We have to update the tree if mz is on RB-tree or
458 * mem is over its softlimit.
460 if (excess || mz->on_tree) {
461 spin_lock(&mctz->lock);
462 /* if on-tree, remove it */
464 __mem_cgroup_remove_exceeded(mem, mz, mctz);
466 * Insert again. mz->usage_in_excess will be updated.
467 * If excess is 0, no tree ops.
469 __mem_cgroup_insert_exceeded(mem, mz, mctz, excess);
470 spin_unlock(&mctz->lock);
475 static void mem_cgroup_remove_from_trees(struct mem_cgroup *mem)
478 struct mem_cgroup_per_zone *mz;
479 struct mem_cgroup_tree_per_zone *mctz;
481 for_each_node_state(node, N_POSSIBLE) {
482 for (zone = 0; zone < MAX_NR_ZONES; zone++) {
483 mz = mem_cgroup_zoneinfo(mem, node, zone);
484 mctz = soft_limit_tree_node_zone(node, zone);
485 mem_cgroup_remove_exceeded(mem, mz, mctz);
490 static struct mem_cgroup_per_zone *
491 __mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
493 struct rb_node *rightmost = NULL;
494 struct mem_cgroup_per_zone *mz;
498 rightmost = rb_last(&mctz->rb_root);
500 goto done; /* Nothing to reclaim from */
502 mz = rb_entry(rightmost, struct mem_cgroup_per_zone, tree_node);
504 * Remove the node now but someone else can add it back,
505 * we will to add it back at the end of reclaim to its correct
506 * position in the tree.
508 __mem_cgroup_remove_exceeded(mz->mem, mz, mctz);
509 if (!res_counter_soft_limit_excess(&mz->mem->res) ||
510 !css_tryget(&mz->mem->css))
516 static struct mem_cgroup_per_zone *
517 mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
519 struct mem_cgroup_per_zone *mz;
521 spin_lock(&mctz->lock);
522 mz = __mem_cgroup_largest_soft_limit_node(mctz);
523 spin_unlock(&mctz->lock);
528 * Implementation Note: reading percpu statistics for memcg.
530 * Both of vmstat[] and percpu_counter has threshold and do periodic
531 * synchronization to implement "quick" read. There are trade-off between
532 * reading cost and precision of value. Then, we may have a chance to implement
533 * a periodic synchronizion of counter in memcg's counter.
535 * But this _read() function is used for user interface now. The user accounts
536 * memory usage by memory cgroup and he _always_ requires exact value because
537 * he accounts memory. Even if we provide quick-and-fuzzy read, we always
538 * have to visit all online cpus and make sum. So, for now, unnecessary
539 * synchronization is not implemented. (just implemented for cpu hotplug)
541 * If there are kernel internal actions which can make use of some not-exact
542 * value, and reading all cpu value can be performance bottleneck in some
543 * common workload, threashold and synchonization as vmstat[] should be
546 static s64 mem_cgroup_read_stat(struct mem_cgroup *mem,
547 enum mem_cgroup_stat_index idx)
553 for_each_online_cpu(cpu)
554 val += per_cpu(mem->stat->count[idx], cpu);
555 #ifdef CONFIG_HOTPLUG_CPU
556 spin_lock(&mem->pcp_counter_lock);
557 val += mem->nocpu_base.count[idx];
558 spin_unlock(&mem->pcp_counter_lock);
564 static s64 mem_cgroup_local_usage(struct mem_cgroup *mem)
568 ret = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_RSS);
569 ret += mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_CACHE);
573 static void mem_cgroup_swap_statistics(struct mem_cgroup *mem,
576 int val = (charge) ? 1 : -1;
577 this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_SWAPOUT], val);
580 static void mem_cgroup_charge_statistics(struct mem_cgroup *mem,
581 bool file, int nr_pages)
586 __this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_CACHE], nr_pages);
588 __this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_RSS], nr_pages);
590 /* pagein of a big page is an event. So, ignore page size */
592 __this_cpu_inc(mem->stat->count[MEM_CGROUP_STAT_PGPGIN_COUNT]);
594 __this_cpu_inc(mem->stat->count[MEM_CGROUP_STAT_PGPGOUT_COUNT]);
595 nr_pages = -nr_pages; /* for event */
598 __this_cpu_add(mem->stat->count[MEM_CGROUP_EVENTS], nr_pages);
603 static unsigned long mem_cgroup_get_local_zonestat(struct mem_cgroup *mem,
607 struct mem_cgroup_per_zone *mz;
610 for_each_online_node(nid)
611 for (zid = 0; zid < MAX_NR_ZONES; zid++) {
612 mz = mem_cgroup_zoneinfo(mem, nid, zid);
613 total += MEM_CGROUP_ZSTAT(mz, idx);
618 static bool __memcg_event_check(struct mem_cgroup *mem, int event_mask_shift)
622 val = this_cpu_read(mem->stat->count[MEM_CGROUP_EVENTS]);
624 return !(val & ((1 << event_mask_shift) - 1));
628 * Check events in order.
631 static void memcg_check_events(struct mem_cgroup *mem, struct page *page)
633 /* threshold event is triggered in finer grain than soft limit */
634 if (unlikely(__memcg_event_check(mem, THRESHOLDS_EVENTS_THRESH))) {
635 mem_cgroup_threshold(mem);
636 if (unlikely(__memcg_event_check(mem, SOFTLIMIT_EVENTS_THRESH)))
637 mem_cgroup_update_tree(mem, page);
641 static struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont)
643 return container_of(cgroup_subsys_state(cont,
644 mem_cgroup_subsys_id), struct mem_cgroup,
648 struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
651 * mm_update_next_owner() may clear mm->owner to NULL
652 * if it races with swapoff, page migration, etc.
653 * So this can be called with p == NULL.
658 return container_of(task_subsys_state(p, mem_cgroup_subsys_id),
659 struct mem_cgroup, css);
662 static struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm)
664 struct mem_cgroup *mem = NULL;
669 * Because we have no locks, mm->owner's may be being moved to other
670 * cgroup. We use css_tryget() here even if this looks
671 * pessimistic (rather than adding locks here).
675 mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
678 } while (!css_tryget(&mem->css));
683 /* The caller has to guarantee "mem" exists before calling this */
684 static struct mem_cgroup *mem_cgroup_start_loop(struct mem_cgroup *mem)
686 struct cgroup_subsys_state *css;
689 if (!mem) /* ROOT cgroup has the smallest ID */
690 return root_mem_cgroup; /*css_put/get against root is ignored*/
691 if (!mem->use_hierarchy) {
692 if (css_tryget(&mem->css))
698 * searching a memory cgroup which has the smallest ID under given
699 * ROOT cgroup. (ID >= 1)
701 css = css_get_next(&mem_cgroup_subsys, 1, &mem->css, &found);
702 if (css && css_tryget(css))
703 mem = container_of(css, struct mem_cgroup, css);
710 static struct mem_cgroup *mem_cgroup_get_next(struct mem_cgroup *iter,
711 struct mem_cgroup *root,
714 int nextid = css_id(&iter->css) + 1;
717 struct cgroup_subsys_state *css;
719 hierarchy_used = iter->use_hierarchy;
722 /* If no ROOT, walk all, ignore hierarchy */
723 if (!cond || (root && !hierarchy_used))
727 root = root_mem_cgroup;
733 css = css_get_next(&mem_cgroup_subsys, nextid,
735 if (css && css_tryget(css))
736 iter = container_of(css, struct mem_cgroup, css);
738 /* If css is NULL, no more cgroups will be found */
740 } while (css && !iter);
745 * for_eacn_mem_cgroup_tree() for visiting all cgroup under tree. Please
746 * be careful that "break" loop is not allowed. We have reference count.
747 * Instead of that modify "cond" to be false and "continue" to exit the loop.
749 #define for_each_mem_cgroup_tree_cond(iter, root, cond) \
750 for (iter = mem_cgroup_start_loop(root);\
752 iter = mem_cgroup_get_next(iter, root, cond))
754 #define for_each_mem_cgroup_tree(iter, root) \
755 for_each_mem_cgroup_tree_cond(iter, root, true)
757 #define for_each_mem_cgroup_all(iter) \
758 for_each_mem_cgroup_tree_cond(iter, NULL, true)
761 static inline bool mem_cgroup_is_root(struct mem_cgroup *mem)
763 return (mem == root_mem_cgroup);
767 * Following LRU functions are allowed to be used without PCG_LOCK.
768 * Operations are called by routine of global LRU independently from memcg.
769 * What we have to take care of here is validness of pc->mem_cgroup.
771 * Changes to pc->mem_cgroup happens when
774 * In typical case, "charge" is done before add-to-lru. Exception is SwapCache.
775 * It is added to LRU before charge.
776 * If PCG_USED bit is not set, page_cgroup is not added to this private LRU.
777 * When moving account, the page is not on LRU. It's isolated.
780 void mem_cgroup_del_lru_list(struct page *page, enum lru_list lru)
782 struct page_cgroup *pc;
783 struct mem_cgroup_per_zone *mz;
785 if (mem_cgroup_disabled())
787 pc = lookup_page_cgroup(page);
788 /* can happen while we handle swapcache. */
789 if (!TestClearPageCgroupAcctLRU(pc))
791 VM_BUG_ON(!pc->mem_cgroup);
793 * We don't check PCG_USED bit. It's cleared when the "page" is finally
794 * removed from global LRU.
796 mz = page_cgroup_zoneinfo(pc->mem_cgroup, page);
797 /* huge page split is done under lru_lock. so, we have no races. */
798 MEM_CGROUP_ZSTAT(mz, lru) -= 1 << compound_order(page);
799 if (mem_cgroup_is_root(pc->mem_cgroup))
801 VM_BUG_ON(list_empty(&pc->lru));
802 list_del_init(&pc->lru);
805 void mem_cgroup_del_lru(struct page *page)
807 mem_cgroup_del_lru_list(page, page_lru(page));
811 * Writeback is about to end against a page which has been marked for immediate
812 * reclaim. If it still appears to be reclaimable, move it to the tail of the
815 void mem_cgroup_rotate_reclaimable_page(struct page *page)
817 struct mem_cgroup_per_zone *mz;
818 struct page_cgroup *pc;
819 enum lru_list lru = page_lru(page);
821 if (mem_cgroup_disabled())
824 pc = lookup_page_cgroup(page);
825 /* unused or root page is not rotated. */
826 if (!PageCgroupUsed(pc))
828 /* Ensure pc->mem_cgroup is visible after reading PCG_USED. */
830 if (mem_cgroup_is_root(pc->mem_cgroup))
832 mz = page_cgroup_zoneinfo(pc->mem_cgroup, page);
833 list_move_tail(&pc->lru, &mz->lists[lru]);
836 void mem_cgroup_rotate_lru_list(struct page *page, enum lru_list lru)
838 struct mem_cgroup_per_zone *mz;
839 struct page_cgroup *pc;
841 if (mem_cgroup_disabled())
844 pc = lookup_page_cgroup(page);
845 /* unused or root page is not rotated. */
846 if (!PageCgroupUsed(pc))
848 /* Ensure pc->mem_cgroup is visible after reading PCG_USED. */
850 if (mem_cgroup_is_root(pc->mem_cgroup))
852 mz = page_cgroup_zoneinfo(pc->mem_cgroup, page);
853 list_move(&pc->lru, &mz->lists[lru]);
856 void mem_cgroup_add_lru_list(struct page *page, enum lru_list lru)
858 struct page_cgroup *pc;
859 struct mem_cgroup_per_zone *mz;
861 if (mem_cgroup_disabled())
863 pc = lookup_page_cgroup(page);
864 VM_BUG_ON(PageCgroupAcctLRU(pc));
865 if (!PageCgroupUsed(pc))
867 /* Ensure pc->mem_cgroup is visible after reading PCG_USED. */
869 mz = page_cgroup_zoneinfo(pc->mem_cgroup, page);
870 /* huge page split is done under lru_lock. so, we have no races. */
871 MEM_CGROUP_ZSTAT(mz, lru) += 1 << compound_order(page);
872 SetPageCgroupAcctLRU(pc);
873 if (mem_cgroup_is_root(pc->mem_cgroup))
875 list_add(&pc->lru, &mz->lists[lru]);
879 * At handling SwapCache, pc->mem_cgroup may be changed while it's linked to
880 * lru because the page may.be reused after it's fully uncharged (because of
881 * SwapCache behavior).To handle that, unlink page_cgroup from LRU when charge
882 * it again. This function is only used to charge SwapCache. It's done under
883 * lock_page and expected that zone->lru_lock is never held.
885 static void mem_cgroup_lru_del_before_commit_swapcache(struct page *page)
888 struct zone *zone = page_zone(page);
889 struct page_cgroup *pc = lookup_page_cgroup(page);
891 spin_lock_irqsave(&zone->lru_lock, flags);
893 * Forget old LRU when this page_cgroup is *not* used. This Used bit
894 * is guarded by lock_page() because the page is SwapCache.
896 if (!PageCgroupUsed(pc))
897 mem_cgroup_del_lru_list(page, page_lru(page));
898 spin_unlock_irqrestore(&zone->lru_lock, flags);
901 static void mem_cgroup_lru_add_after_commit_swapcache(struct page *page)
904 struct zone *zone = page_zone(page);
905 struct page_cgroup *pc = lookup_page_cgroup(page);
907 spin_lock_irqsave(&zone->lru_lock, flags);
908 /* link when the page is linked to LRU but page_cgroup isn't */
909 if (PageLRU(page) && !PageCgroupAcctLRU(pc))
910 mem_cgroup_add_lru_list(page, page_lru(page));
911 spin_unlock_irqrestore(&zone->lru_lock, flags);
915 void mem_cgroup_move_lists(struct page *page,
916 enum lru_list from, enum lru_list to)
918 if (mem_cgroup_disabled())
920 mem_cgroup_del_lru_list(page, from);
921 mem_cgroup_add_lru_list(page, to);
924 int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem)
927 struct mem_cgroup *curr = NULL;
928 struct task_struct *p;
930 p = find_lock_task_mm(task);
933 curr = try_get_mem_cgroup_from_mm(p->mm);
938 * We should check use_hierarchy of "mem" not "curr". Because checking
939 * use_hierarchy of "curr" here make this function true if hierarchy is
940 * enabled in "curr" and "curr" is a child of "mem" in *cgroup*
941 * hierarchy(even if use_hierarchy is disabled in "mem").
943 if (mem->use_hierarchy)
944 ret = css_is_ancestor(&curr->css, &mem->css);
951 static int calc_inactive_ratio(struct mem_cgroup *memcg, unsigned long *present_pages)
953 unsigned long active;
954 unsigned long inactive;
956 unsigned long inactive_ratio;
958 inactive = mem_cgroup_get_local_zonestat(memcg, LRU_INACTIVE_ANON);
959 active = mem_cgroup_get_local_zonestat(memcg, LRU_ACTIVE_ANON);
961 gb = (inactive + active) >> (30 - PAGE_SHIFT);
963 inactive_ratio = int_sqrt(10 * gb);
968 present_pages[0] = inactive;
969 present_pages[1] = active;
972 return inactive_ratio;
975 int mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg)
977 unsigned long active;
978 unsigned long inactive;
979 unsigned long present_pages[2];
980 unsigned long inactive_ratio;
982 inactive_ratio = calc_inactive_ratio(memcg, present_pages);
984 inactive = present_pages[0];
985 active = present_pages[1];
987 if (inactive * inactive_ratio < active)
993 int mem_cgroup_inactive_file_is_low(struct mem_cgroup *memcg)
995 unsigned long active;
996 unsigned long inactive;
998 inactive = mem_cgroup_get_local_zonestat(memcg, LRU_INACTIVE_FILE);
999 active = mem_cgroup_get_local_zonestat(memcg, LRU_ACTIVE_FILE);
1001 return (active > inactive);
1004 unsigned long mem_cgroup_zone_nr_pages(struct mem_cgroup *memcg,
1008 int nid = zone_to_nid(zone);
1009 int zid = zone_idx(zone);
1010 struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid);
1012 return MEM_CGROUP_ZSTAT(mz, lru);
1015 struct zone_reclaim_stat *mem_cgroup_get_reclaim_stat(struct mem_cgroup *memcg,
1018 int nid = zone_to_nid(zone);
1019 int zid = zone_idx(zone);
1020 struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid);
1022 return &mz->reclaim_stat;
1025 struct zone_reclaim_stat *
1026 mem_cgroup_get_reclaim_stat_from_page(struct page *page)
1028 struct page_cgroup *pc;
1029 struct mem_cgroup_per_zone *mz;
1031 if (mem_cgroup_disabled())
1034 pc = lookup_page_cgroup(page);
1035 if (!PageCgroupUsed(pc))
1037 /* Ensure pc->mem_cgroup is visible after reading PCG_USED. */
1039 mz = page_cgroup_zoneinfo(pc->mem_cgroup, page);
1040 return &mz->reclaim_stat;
1043 unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
1044 struct list_head *dst,
1045 unsigned long *scanned, int order,
1046 int mode, struct zone *z,
1047 struct mem_cgroup *mem_cont,
1048 int active, int file)
1050 unsigned long nr_taken = 0;
1054 struct list_head *src;
1055 struct page_cgroup *pc, *tmp;
1056 int nid = zone_to_nid(z);
1057 int zid = zone_idx(z);
1058 struct mem_cgroup_per_zone *mz;
1059 int lru = LRU_FILE * file + active;
1063 mz = mem_cgroup_zoneinfo(mem_cont, nid, zid);
1064 src = &mz->lists[lru];
1067 list_for_each_entry_safe_reverse(pc, tmp, src, lru) {
1068 if (scan >= nr_to_scan)
1071 if (unlikely(!PageCgroupUsed(pc)))
1074 page = lookup_cgroup_page(pc);
1076 if (unlikely(!PageLRU(page)))
1080 ret = __isolate_lru_page(page, mode, file);
1083 list_move(&page->lru, dst);
1084 mem_cgroup_del_lru(page);
1085 nr_taken += hpage_nr_pages(page);
1088 /* we don't affect global LRU but rotate in our LRU */
1089 mem_cgroup_rotate_lru_list(page, page_lru(page));
1098 trace_mm_vmscan_memcg_isolate(0, nr_to_scan, scan, nr_taken,
1104 #define mem_cgroup_from_res_counter(counter, member) \
1105 container_of(counter, struct mem_cgroup, member)
1108 * mem_cgroup_margin - calculate chargeable space of a memory cgroup
1109 * @mem: the memory cgroup
1111 * Returns the maximum amount of memory @mem can be charged with, in
1114 static unsigned long long mem_cgroup_margin(struct mem_cgroup *mem)
1116 unsigned long long margin;
1118 margin = res_counter_margin(&mem->res);
1119 if (do_swap_account)
1120 margin = min(margin, res_counter_margin(&mem->memsw));
1124 static unsigned int get_swappiness(struct mem_cgroup *memcg)
1126 struct cgroup *cgrp = memcg->css.cgroup;
1129 if (cgrp->parent == NULL)
1130 return vm_swappiness;
1132 return memcg->swappiness;
1135 static void mem_cgroup_start_move(struct mem_cgroup *mem)
1140 spin_lock(&mem->pcp_counter_lock);
1141 for_each_online_cpu(cpu)
1142 per_cpu(mem->stat->count[MEM_CGROUP_ON_MOVE], cpu) += 1;
1143 mem->nocpu_base.count[MEM_CGROUP_ON_MOVE] += 1;
1144 spin_unlock(&mem->pcp_counter_lock);
1150 static void mem_cgroup_end_move(struct mem_cgroup *mem)
1157 spin_lock(&mem->pcp_counter_lock);
1158 for_each_online_cpu(cpu)
1159 per_cpu(mem->stat->count[MEM_CGROUP_ON_MOVE], cpu) -= 1;
1160 mem->nocpu_base.count[MEM_CGROUP_ON_MOVE] -= 1;
1161 spin_unlock(&mem->pcp_counter_lock);
1165 * 2 routines for checking "mem" is under move_account() or not.
1167 * mem_cgroup_stealed() - checking a cgroup is mc.from or not. This is used
1168 * for avoiding race in accounting. If true,
1169 * pc->mem_cgroup may be overwritten.
1171 * mem_cgroup_under_move() - checking a cgroup is mc.from or mc.to or
1172 * under hierarchy of moving cgroups. This is for
1173 * waiting at hith-memory prressure caused by "move".
1176 static bool mem_cgroup_stealed(struct mem_cgroup *mem)
1178 VM_BUG_ON(!rcu_read_lock_held());
1179 return this_cpu_read(mem->stat->count[MEM_CGROUP_ON_MOVE]) > 0;
1182 static bool mem_cgroup_under_move(struct mem_cgroup *mem)
1184 struct mem_cgroup *from;
1185 struct mem_cgroup *to;
1188 * Unlike task_move routines, we access mc.to, mc.from not under
1189 * mutual exclusion by cgroup_mutex. Here, we take spinlock instead.
1191 spin_lock(&mc.lock);
1196 if (from == mem || to == mem
1197 || (mem->use_hierarchy && css_is_ancestor(&from->css, &mem->css))
1198 || (mem->use_hierarchy && css_is_ancestor(&to->css, &mem->css)))
1201 spin_unlock(&mc.lock);
1205 static bool mem_cgroup_wait_acct_move(struct mem_cgroup *mem)
1207 if (mc.moving_task && current != mc.moving_task) {
1208 if (mem_cgroup_under_move(mem)) {
1210 prepare_to_wait(&mc.waitq, &wait, TASK_INTERRUPTIBLE);
1211 /* moving charge context might have finished. */
1214 finish_wait(&mc.waitq, &wait);
1222 * mem_cgroup_print_oom_info: Called from OOM with tasklist_lock held in read mode.
1223 * @memcg: The memory cgroup that went over limit
1224 * @p: Task that is going to be killed
1226 * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is
1229 void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
1231 struct cgroup *task_cgrp;
1232 struct cgroup *mem_cgrp;
1234 * Need a buffer in BSS, can't rely on allocations. The code relies
1235 * on the assumption that OOM is serialized for memory controller.
1236 * If this assumption is broken, revisit this code.
1238 static char memcg_name[PATH_MAX];
1247 mem_cgrp = memcg->css.cgroup;
1248 task_cgrp = task_cgroup(p, mem_cgroup_subsys_id);
1250 ret = cgroup_path(task_cgrp, memcg_name, PATH_MAX);
1253 * Unfortunately, we are unable to convert to a useful name
1254 * But we'll still print out the usage information
1261 printk(KERN_INFO "Task in %s killed", memcg_name);
1264 ret = cgroup_path(mem_cgrp, memcg_name, PATH_MAX);
1272 * Continues from above, so we don't need an KERN_ level
1274 printk(KERN_CONT " as a result of limit of %s\n", memcg_name);
1277 printk(KERN_INFO "memory: usage %llukB, limit %llukB, failcnt %llu\n",
1278 res_counter_read_u64(&memcg->res, RES_USAGE) >> 10,
1279 res_counter_read_u64(&memcg->res, RES_LIMIT) >> 10,
1280 res_counter_read_u64(&memcg->res, RES_FAILCNT));
1281 printk(KERN_INFO "memory+swap: usage %llukB, limit %llukB, "
1283 res_counter_read_u64(&memcg->memsw, RES_USAGE) >> 10,
1284 res_counter_read_u64(&memcg->memsw, RES_LIMIT) >> 10,
1285 res_counter_read_u64(&memcg->memsw, RES_FAILCNT));
1289 * This function returns the number of memcg under hierarchy tree. Returns
1290 * 1(self count) if no children.
1292 static int mem_cgroup_count_children(struct mem_cgroup *mem)
1295 struct mem_cgroup *iter;
1297 for_each_mem_cgroup_tree(iter, mem)
1303 * Return the memory (and swap, if configured) limit for a memcg.
1305 u64 mem_cgroup_get_limit(struct mem_cgroup *memcg)
1310 limit = res_counter_read_u64(&memcg->res, RES_LIMIT);
1311 limit += total_swap_pages << PAGE_SHIFT;
1313 memsw = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
1315 * If memsw is finite and limits the amount of swap space available
1316 * to this memcg, return that limit.
1318 return min(limit, memsw);
1322 * Visit the first child (need not be the first child as per the ordering
1323 * of the cgroup list, since we track last_scanned_child) of @mem and use
1324 * that to reclaim free pages from.
1326 static struct mem_cgroup *
1327 mem_cgroup_select_victim(struct mem_cgroup *root_mem)
1329 struct mem_cgroup *ret = NULL;
1330 struct cgroup_subsys_state *css;
1333 if (!root_mem->use_hierarchy) {
1334 css_get(&root_mem->css);
1340 nextid = root_mem->last_scanned_child + 1;
1341 css = css_get_next(&mem_cgroup_subsys, nextid, &root_mem->css,
1343 if (css && css_tryget(css))
1344 ret = container_of(css, struct mem_cgroup, css);
1347 /* Updates scanning parameter */
1349 /* this means start scan from ID:1 */
1350 root_mem->last_scanned_child = 0;
1352 root_mem->last_scanned_child = found;
1359 * Scan the hierarchy if needed to reclaim memory. We remember the last child
1360 * we reclaimed from, so that we don't end up penalizing one child extensively
1361 * based on its position in the children list.
1363 * root_mem is the original ancestor that we've been reclaim from.
1365 * We give up and return to the caller when we visit root_mem twice.
1366 * (other groups can be removed while we're walking....)
1368 * If shrink==true, for avoiding to free too much, this returns immedieately.
1370 static int mem_cgroup_hierarchical_reclaim(struct mem_cgroup *root_mem,
1373 unsigned long reclaim_options)
1375 struct mem_cgroup *victim;
1378 bool noswap = reclaim_options & MEM_CGROUP_RECLAIM_NOSWAP;
1379 bool shrink = reclaim_options & MEM_CGROUP_RECLAIM_SHRINK;
1380 bool check_soft = reclaim_options & MEM_CGROUP_RECLAIM_SOFT;
1381 unsigned long excess;
1383 excess = res_counter_soft_limit_excess(&root_mem->res) >> PAGE_SHIFT;
1385 /* If memsw_is_minimum==1, swap-out is of-no-use. */
1386 if (root_mem->memsw_is_minimum)
1390 victim = mem_cgroup_select_victim(root_mem);
1391 if (victim == root_mem) {
1394 drain_all_stock_async();
1397 * If we have not been able to reclaim
1398 * anything, it might because there are
1399 * no reclaimable pages under this hierarchy
1401 if (!check_soft || !total) {
1402 css_put(&victim->css);
1406 * We want to do more targetted reclaim.
1407 * excess >> 2 is not to excessive so as to
1408 * reclaim too much, nor too less that we keep
1409 * coming back to reclaim from this cgroup
1411 if (total >= (excess >> 2) ||
1412 (loop > MEM_CGROUP_MAX_RECLAIM_LOOPS)) {
1413 css_put(&victim->css);
1418 if (!mem_cgroup_local_usage(victim)) {
1419 /* this cgroup's local usage == 0 */
1420 css_put(&victim->css);
1423 /* we use swappiness of local cgroup */
1425 ret = mem_cgroup_shrink_node_zone(victim, gfp_mask,
1426 noswap, get_swappiness(victim), zone);
1428 ret = try_to_free_mem_cgroup_pages(victim, gfp_mask,
1429 noswap, get_swappiness(victim));
1430 css_put(&victim->css);
1432 * At shrinking usage, we can't check we should stop here or
1433 * reclaim more. It's depends on callers. last_scanned_child
1434 * will work enough for keeping fairness under tree.
1440 if (!res_counter_soft_limit_excess(&root_mem->res))
1442 } else if (mem_cgroup_margin(root_mem))
1449 * Check OOM-Killer is already running under our hierarchy.
1450 * If someone is running, return false.
1452 static bool mem_cgroup_oom_lock(struct mem_cgroup *mem)
1454 int x, lock_count = 0;
1455 struct mem_cgroup *iter;
1457 for_each_mem_cgroup_tree(iter, mem) {
1458 x = atomic_inc_return(&iter->oom_lock);
1459 lock_count = max(x, lock_count);
1462 if (lock_count == 1)
1467 static int mem_cgroup_oom_unlock(struct mem_cgroup *mem)
1469 struct mem_cgroup *iter;
1472 * When a new child is created while the hierarchy is under oom,
1473 * mem_cgroup_oom_lock() may not be called. We have to use
1474 * atomic_add_unless() here.
1476 for_each_mem_cgroup_tree(iter, mem)
1477 atomic_add_unless(&iter->oom_lock, -1, 0);
1482 static DEFINE_MUTEX(memcg_oom_mutex);
1483 static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq);
1485 struct oom_wait_info {
1486 struct mem_cgroup *mem;
1490 static int memcg_oom_wake_function(wait_queue_t *wait,
1491 unsigned mode, int sync, void *arg)
1493 struct mem_cgroup *wake_mem = (struct mem_cgroup *)arg;
1494 struct oom_wait_info *oom_wait_info;
1496 oom_wait_info = container_of(wait, struct oom_wait_info, wait);
1498 if (oom_wait_info->mem == wake_mem)
1500 /* if no hierarchy, no match */
1501 if (!oom_wait_info->mem->use_hierarchy || !wake_mem->use_hierarchy)
1504 * Both of oom_wait_info->mem and wake_mem are stable under us.
1505 * Then we can use css_is_ancestor without taking care of RCU.
1507 if (!css_is_ancestor(&oom_wait_info->mem->css, &wake_mem->css) &&
1508 !css_is_ancestor(&wake_mem->css, &oom_wait_info->mem->css))
1512 return autoremove_wake_function(wait, mode, sync, arg);
1515 static void memcg_wakeup_oom(struct mem_cgroup *mem)
1517 /* for filtering, pass "mem" as argument. */
1518 __wake_up(&memcg_oom_waitq, TASK_NORMAL, 0, mem);
1521 static void memcg_oom_recover(struct mem_cgroup *mem)
1523 if (mem && atomic_read(&mem->oom_lock))
1524 memcg_wakeup_oom(mem);
1528 * try to call OOM killer. returns false if we should exit memory-reclaim loop.
1530 bool mem_cgroup_handle_oom(struct mem_cgroup *mem, gfp_t mask)
1532 struct oom_wait_info owait;
1533 bool locked, need_to_kill;
1536 owait.wait.flags = 0;
1537 owait.wait.func = memcg_oom_wake_function;
1538 owait.wait.private = current;
1539 INIT_LIST_HEAD(&owait.wait.task_list);
1540 need_to_kill = true;
1541 /* At first, try to OOM lock hierarchy under mem.*/
1542 mutex_lock(&memcg_oom_mutex);
1543 locked = mem_cgroup_oom_lock(mem);
1545 * Even if signal_pending(), we can't quit charge() loop without
1546 * accounting. So, UNINTERRUPTIBLE is appropriate. But SIGKILL
1547 * under OOM is always welcomed, use TASK_KILLABLE here.
1549 prepare_to_wait(&memcg_oom_waitq, &owait.wait, TASK_KILLABLE);
1550 if (!locked || mem->oom_kill_disable)
1551 need_to_kill = false;
1553 mem_cgroup_oom_notify(mem);
1554 mutex_unlock(&memcg_oom_mutex);
1557 finish_wait(&memcg_oom_waitq, &owait.wait);
1558 mem_cgroup_out_of_memory(mem, mask);
1561 finish_wait(&memcg_oom_waitq, &owait.wait);
1563 mutex_lock(&memcg_oom_mutex);
1564 mem_cgroup_oom_unlock(mem);
1565 memcg_wakeup_oom(mem);
1566 mutex_unlock(&memcg_oom_mutex);
1568 if (test_thread_flag(TIF_MEMDIE) || fatal_signal_pending(current))
1570 /* Give chance to dying process */
1571 schedule_timeout(1);
1576 * Currently used to update mapped file statistics, but the routine can be
1577 * generalized to update other statistics as well.
1579 * Notes: Race condition
1581 * We usually use page_cgroup_lock() for accessing page_cgroup member but
1582 * it tends to be costly. But considering some conditions, we doesn't need
1583 * to do so _always_.
1585 * Considering "charge", lock_page_cgroup() is not required because all
1586 * file-stat operations happen after a page is attached to radix-tree. There
1587 * are no race with "charge".
1589 * Considering "uncharge", we know that memcg doesn't clear pc->mem_cgroup
1590 * at "uncharge" intentionally. So, we always see valid pc->mem_cgroup even
1591 * if there are race with "uncharge". Statistics itself is properly handled
1594 * Considering "move", this is an only case we see a race. To make the race
1595 * small, we check MEM_CGROUP_ON_MOVE percpu value and detect there are
1596 * possibility of race condition. If there is, we take a lock.
1599 void mem_cgroup_update_page_stat(struct page *page,
1600 enum mem_cgroup_page_stat_item idx, int val)
1602 struct mem_cgroup *mem;
1603 struct page_cgroup *pc = lookup_page_cgroup(page);
1604 bool need_unlock = false;
1605 unsigned long uninitialized_var(flags);
1611 mem = pc->mem_cgroup;
1612 if (unlikely(!mem || !PageCgroupUsed(pc)))
1614 /* pc->mem_cgroup is unstable ? */
1615 if (unlikely(mem_cgroup_stealed(mem)) || PageTransHuge(page)) {
1616 /* take a lock against to access pc->mem_cgroup */
1617 move_lock_page_cgroup(pc, &flags);
1619 mem = pc->mem_cgroup;
1620 if (!mem || !PageCgroupUsed(pc))
1625 case MEMCG_NR_FILE_MAPPED:
1627 SetPageCgroupFileMapped(pc);
1628 else if (!page_mapped(page))
1629 ClearPageCgroupFileMapped(pc);
1630 idx = MEM_CGROUP_STAT_FILE_MAPPED;
1636 this_cpu_add(mem->stat->count[idx], val);
1639 if (unlikely(need_unlock))
1640 move_unlock_page_cgroup(pc, &flags);
1644 EXPORT_SYMBOL(mem_cgroup_update_page_stat);
1647 * size of first charge trial. "32" comes from vmscan.c's magic value.
1648 * TODO: maybe necessary to use big numbers in big irons.
1650 #define CHARGE_SIZE (32 * PAGE_SIZE)
1651 struct memcg_stock_pcp {
1652 struct mem_cgroup *cached; /* this never be root cgroup */
1653 unsigned int nr_pages;
1654 struct work_struct work;
1656 static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock);
1657 static atomic_t memcg_drain_count;
1660 * Try to consume stocked charge on this cpu. If success, one page is consumed
1661 * from local stock and true is returned. If the stock is 0 or charges from a
1662 * cgroup which is not current target, returns false. This stock will be
1665 static bool consume_stock(struct mem_cgroup *mem)
1667 struct memcg_stock_pcp *stock;
1670 stock = &get_cpu_var(memcg_stock);
1671 if (mem == stock->cached && stock->nr_pages)
1673 else /* need to call res_counter_charge */
1675 put_cpu_var(memcg_stock);
1680 * Returns stocks cached in percpu to res_counter and reset cached information.
1682 static void drain_stock(struct memcg_stock_pcp *stock)
1684 struct mem_cgroup *old = stock->cached;
1686 if (stock->nr_pages) {
1687 unsigned long bytes = stock->nr_pages * PAGE_SIZE;
1689 res_counter_uncharge(&old->res, bytes);
1690 if (do_swap_account)
1691 res_counter_uncharge(&old->memsw, bytes);
1692 stock->nr_pages = 0;
1694 stock->cached = NULL;
1698 * This must be called under preempt disabled or must be called by
1699 * a thread which is pinned to local cpu.
1701 static void drain_local_stock(struct work_struct *dummy)
1703 struct memcg_stock_pcp *stock = &__get_cpu_var(memcg_stock);
1708 * Cache charges(val) which is from res_counter, to local per_cpu area.
1709 * This will be consumed by consume_stock() function, later.
1711 static void refill_stock(struct mem_cgroup *mem, unsigned int nr_pages)
1713 struct memcg_stock_pcp *stock = &get_cpu_var(memcg_stock);
1715 if (stock->cached != mem) { /* reset if necessary */
1717 stock->cached = mem;
1719 stock->nr_pages += nr_pages;
1720 put_cpu_var(memcg_stock);
1724 * Tries to drain stocked charges in other cpus. This function is asynchronous
1725 * and just put a work per cpu for draining localy on each cpu. Caller can
1726 * expects some charges will be back to res_counter later but cannot wait for
1729 static void drain_all_stock_async(void)
1732 /* This function is for scheduling "drain" in asynchronous way.
1733 * The result of "drain" is not directly handled by callers. Then,
1734 * if someone is calling drain, we don't have to call drain more.
1735 * Anyway, WORK_STRUCT_PENDING check in queue_work_on() will catch if
1736 * there is a race. We just do loose check here.
1738 if (atomic_read(&memcg_drain_count))
1740 /* Notify other cpus that system-wide "drain" is running */
1741 atomic_inc(&memcg_drain_count);
1743 for_each_online_cpu(cpu) {
1744 struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
1745 schedule_work_on(cpu, &stock->work);
1748 atomic_dec(&memcg_drain_count);
1749 /* We don't wait for flush_work */
1752 /* This is a synchronous drain interface. */
1753 static void drain_all_stock_sync(void)
1755 /* called when force_empty is called */
1756 atomic_inc(&memcg_drain_count);
1757 schedule_on_each_cpu(drain_local_stock);
1758 atomic_dec(&memcg_drain_count);
1762 * This function drains percpu counter value from DEAD cpu and
1763 * move it to local cpu. Note that this function can be preempted.
1765 static void mem_cgroup_drain_pcp_counter(struct mem_cgroup *mem, int cpu)
1769 spin_lock(&mem->pcp_counter_lock);
1770 for (i = 0; i < MEM_CGROUP_STAT_DATA; i++) {
1771 s64 x = per_cpu(mem->stat->count[i], cpu);
1773 per_cpu(mem->stat->count[i], cpu) = 0;
1774 mem->nocpu_base.count[i] += x;
1776 /* need to clear ON_MOVE value, works as a kind of lock. */
1777 per_cpu(mem->stat->count[MEM_CGROUP_ON_MOVE], cpu) = 0;
1778 spin_unlock(&mem->pcp_counter_lock);
1781 static void synchronize_mem_cgroup_on_move(struct mem_cgroup *mem, int cpu)
1783 int idx = MEM_CGROUP_ON_MOVE;
1785 spin_lock(&mem->pcp_counter_lock);
1786 per_cpu(mem->stat->count[idx], cpu) = mem->nocpu_base.count[idx];
1787 spin_unlock(&mem->pcp_counter_lock);
1790 static int __cpuinit memcg_cpu_hotplug_callback(struct notifier_block *nb,
1791 unsigned long action,
1794 int cpu = (unsigned long)hcpu;
1795 struct memcg_stock_pcp *stock;
1796 struct mem_cgroup *iter;
1798 if ((action == CPU_ONLINE)) {
1799 for_each_mem_cgroup_all(iter)
1800 synchronize_mem_cgroup_on_move(iter, cpu);
1804 if ((action != CPU_DEAD) || action != CPU_DEAD_FROZEN)
1807 for_each_mem_cgroup_all(iter)
1808 mem_cgroup_drain_pcp_counter(iter, cpu);
1810 stock = &per_cpu(memcg_stock, cpu);
1816 /* See __mem_cgroup_try_charge() for details */
1818 CHARGE_OK, /* success */
1819 CHARGE_RETRY, /* need to retry but retry is not bad */
1820 CHARGE_NOMEM, /* we can't do more. return -ENOMEM */
1821 CHARGE_WOULDBLOCK, /* GFP_WAIT wasn't set and no enough res. */
1822 CHARGE_OOM_DIE, /* the current is killed because of OOM */
1825 static int __mem_cgroup_do_charge(struct mem_cgroup *mem, gfp_t gfp_mask,
1826 int csize, bool oom_check)
1828 struct mem_cgroup *mem_over_limit;
1829 struct res_counter *fail_res;
1830 unsigned long flags = 0;
1833 ret = res_counter_charge(&mem->res, csize, &fail_res);
1836 if (!do_swap_account)
1838 ret = res_counter_charge(&mem->memsw, csize, &fail_res);
1842 res_counter_uncharge(&mem->res, csize);
1843 mem_over_limit = mem_cgroup_from_res_counter(fail_res, memsw);
1844 flags |= MEM_CGROUP_RECLAIM_NOSWAP;
1846 mem_over_limit = mem_cgroup_from_res_counter(fail_res, res);
1848 * csize can be either a huge page (HPAGE_SIZE), a batch of
1849 * regular pages (CHARGE_SIZE), or a single regular page
1852 * Never reclaim on behalf of optional batching, retry with a
1853 * single page instead.
1855 if (csize == CHARGE_SIZE)
1856 return CHARGE_RETRY;
1858 if (!(gfp_mask & __GFP_WAIT))
1859 return CHARGE_WOULDBLOCK;
1861 ret = mem_cgroup_hierarchical_reclaim(mem_over_limit, NULL,
1863 if (mem_cgroup_margin(mem_over_limit) >= csize)
1864 return CHARGE_RETRY;
1866 * Even though the limit is exceeded at this point, reclaim
1867 * may have been able to free some pages. Retry the charge
1868 * before killing the task.
1870 * Only for regular pages, though: huge pages are rather
1871 * unlikely to succeed so close to the limit, and we fall back
1872 * to regular pages anyway in case of failure.
1874 if (csize == PAGE_SIZE && ret)
1875 return CHARGE_RETRY;
1878 * At task move, charge accounts can be doubly counted. So, it's
1879 * better to wait until the end of task_move if something is going on.
1881 if (mem_cgroup_wait_acct_move(mem_over_limit))
1882 return CHARGE_RETRY;
1884 /* If we don't need to call oom-killer at el, return immediately */
1886 return CHARGE_NOMEM;
1888 if (!mem_cgroup_handle_oom(mem_over_limit, gfp_mask))
1889 return CHARGE_OOM_DIE;
1891 return CHARGE_RETRY;
1895 * Unlike exported interface, "oom" parameter is added. if oom==true,
1896 * oom-killer can be invoked.
1898 static int __mem_cgroup_try_charge(struct mm_struct *mm,
1900 struct mem_cgroup **memcg, bool oom,
1903 int nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES;
1904 struct mem_cgroup *mem = NULL;
1906 int csize = max(CHARGE_SIZE, (unsigned long) page_size);
1909 * Unlike gloval-vm's OOM-kill, we're not in memory shortage
1910 * in system level. So, allow to go ahead dying process in addition to
1913 if (unlikely(test_thread_flag(TIF_MEMDIE)
1914 || fatal_signal_pending(current)))
1918 * We always charge the cgroup the mm_struct belongs to.
1919 * The mm_struct's mem_cgroup changes on task migration if the
1920 * thread group leader migrates. It's possible that mm is not
1921 * set, if so charge the init_mm (happens for pagecache usage).
1926 if (*memcg) { /* css should be a valid one */
1928 VM_BUG_ON(css_is_removed(&mem->css));
1929 if (mem_cgroup_is_root(mem))
1931 if (page_size == PAGE_SIZE && consume_stock(mem))
1935 struct task_struct *p;
1938 p = rcu_dereference(mm->owner);
1940 * Because we don't have task_lock(), "p" can exit.
1941 * In that case, "mem" can point to root or p can be NULL with
1942 * race with swapoff. Then, we have small risk of mis-accouning.
1943 * But such kind of mis-account by race always happens because
1944 * we don't have cgroup_mutex(). It's overkill and we allo that
1946 * (*) swapoff at el will charge against mm-struct not against
1947 * task-struct. So, mm->owner can be NULL.
1949 mem = mem_cgroup_from_task(p);
1950 if (!mem || mem_cgroup_is_root(mem)) {
1954 if (page_size == PAGE_SIZE && consume_stock(mem)) {
1956 * It seems dagerous to access memcg without css_get().
1957 * But considering how consume_stok works, it's not
1958 * necessary. If consume_stock success, some charges
1959 * from this memcg are cached on this cpu. So, we
1960 * don't need to call css_get()/css_tryget() before
1961 * calling consume_stock().
1966 /* after here, we may be blocked. we need to get refcnt */
1967 if (!css_tryget(&mem->css)) {
1977 /* If killed, bypass charge */
1978 if (fatal_signal_pending(current)) {
1984 if (oom && !nr_oom_retries) {
1986 nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES;
1989 ret = __mem_cgroup_do_charge(mem, gfp_mask, csize, oom_check);
1994 case CHARGE_RETRY: /* not in OOM situation but retry */
1999 case CHARGE_WOULDBLOCK: /* !__GFP_WAIT */
2002 case CHARGE_NOMEM: /* OOM routine works */
2007 /* If oom, we never return -ENOMEM */
2010 case CHARGE_OOM_DIE: /* Killed by OOM Killer */
2014 } while (ret != CHARGE_OK);
2016 if (csize > page_size)
2017 refill_stock(mem, (csize - page_size) >> PAGE_SHIFT);
2031 * Somemtimes we have to undo a charge we got by try_charge().
2032 * This function is for that and do uncharge, put css's refcnt.
2033 * gotten by try_charge().
2035 static void __mem_cgroup_cancel_charge(struct mem_cgroup *mem,
2036 unsigned int nr_pages)
2038 if (!mem_cgroup_is_root(mem)) {
2039 unsigned long bytes = nr_pages * PAGE_SIZE;
2041 res_counter_uncharge(&mem->res, bytes);
2042 if (do_swap_account)
2043 res_counter_uncharge(&mem->memsw, bytes);
2048 * A helper function to get mem_cgroup from ID. must be called under
2049 * rcu_read_lock(). The caller must check css_is_removed() or some if
2050 * it's concern. (dropping refcnt from swap can be called against removed
2053 static struct mem_cgroup *mem_cgroup_lookup(unsigned short id)
2055 struct cgroup_subsys_state *css;
2057 /* ID 0 is unused ID */
2060 css = css_lookup(&mem_cgroup_subsys, id);
2063 return container_of(css, struct mem_cgroup, css);
2066 struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page)
2068 struct mem_cgroup *mem = NULL;
2069 struct page_cgroup *pc;
2073 VM_BUG_ON(!PageLocked(page));
2075 pc = lookup_page_cgroup(page);
2076 lock_page_cgroup(pc);
2077 if (PageCgroupUsed(pc)) {
2078 mem = pc->mem_cgroup;
2079 if (mem && !css_tryget(&mem->css))
2081 } else if (PageSwapCache(page)) {
2082 ent.val = page_private(page);
2083 id = lookup_swap_cgroup(ent);
2085 mem = mem_cgroup_lookup(id);
2086 if (mem && !css_tryget(&mem->css))
2090 unlock_page_cgroup(pc);
2094 static void __mem_cgroup_commit_charge(struct mem_cgroup *mem,
2096 struct page_cgroup *pc,
2097 enum charge_type ctype,
2100 int nr_pages = page_size >> PAGE_SHIFT;
2102 lock_page_cgroup(pc);
2103 if (unlikely(PageCgroupUsed(pc))) {
2104 unlock_page_cgroup(pc);
2105 __mem_cgroup_cancel_charge(mem, nr_pages);
2109 * we don't need page_cgroup_lock about tail pages, becase they are not
2110 * accessed by any other context at this point.
2112 pc->mem_cgroup = mem;
2114 * We access a page_cgroup asynchronously without lock_page_cgroup().
2115 * Especially when a page_cgroup is taken from a page, pc->mem_cgroup
2116 * is accessed after testing USED bit. To make pc->mem_cgroup visible
2117 * before USED bit, we need memory barrier here.
2118 * See mem_cgroup_add_lru_list(), etc.
2122 case MEM_CGROUP_CHARGE_TYPE_CACHE:
2123 case MEM_CGROUP_CHARGE_TYPE_SHMEM:
2124 SetPageCgroupCache(pc);
2125 SetPageCgroupUsed(pc);
2127 case MEM_CGROUP_CHARGE_TYPE_MAPPED:
2128 ClearPageCgroupCache(pc);
2129 SetPageCgroupUsed(pc);
2135 mem_cgroup_charge_statistics(mem, PageCgroupCache(pc), nr_pages);
2136 unlock_page_cgroup(pc);
2138 * "charge_statistics" updated event counter. Then, check it.
2139 * Insert ancestor (and ancestor's ancestors), to softlimit RB-tree.
2140 * if they exceeds softlimit.
2142 memcg_check_events(mem, page);
2145 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
2147 #define PCGF_NOCOPY_AT_SPLIT ((1 << PCG_LOCK) | (1 << PCG_MOVE_LOCK) |\
2148 (1 << PCG_ACCT_LRU) | (1 << PCG_MIGRATION))
2150 * Because tail pages are not marked as "used", set it. We're under
2151 * zone->lru_lock, 'splitting on pmd' and compund_lock.
2153 void mem_cgroup_split_huge_fixup(struct page *head, struct page *tail)
2155 struct page_cgroup *head_pc = lookup_page_cgroup(head);
2156 struct page_cgroup *tail_pc = lookup_page_cgroup(tail);
2157 unsigned long flags;
2159 if (mem_cgroup_disabled())
2162 * We have no races with charge/uncharge but will have races with
2163 * page state accounting.
2165 move_lock_page_cgroup(head_pc, &flags);
2167 tail_pc->mem_cgroup = head_pc->mem_cgroup;
2168 smp_wmb(); /* see __commit_charge() */
2169 if (PageCgroupAcctLRU(head_pc)) {
2171 struct mem_cgroup_per_zone *mz;
2174 * LRU flags cannot be copied because we need to add tail
2175 *.page to LRU by generic call and our hook will be called.
2176 * We hold lru_lock, then, reduce counter directly.
2178 lru = page_lru(head);
2179 mz = page_cgroup_zoneinfo(head_pc->mem_cgroup, head);
2180 MEM_CGROUP_ZSTAT(mz, lru) -= 1;
2182 tail_pc->flags = head_pc->flags & ~PCGF_NOCOPY_AT_SPLIT;
2183 move_unlock_page_cgroup(head_pc, &flags);
2188 * mem_cgroup_move_account - move account of the page
2190 * @pc: page_cgroup of the page.
2191 * @from: mem_cgroup which the page is moved from.
2192 * @to: mem_cgroup which the page is moved to. @from != @to.
2193 * @uncharge: whether we should call uncharge and css_put against @from.
2194 * @charge_size: number of bytes to charge (regular or huge page)
2196 * The caller must confirm following.
2197 * - page is not on LRU (isolate_page() is useful.)
2198 * - compound_lock is held when charge_size > PAGE_SIZE
2200 * This function doesn't do "charge" nor css_get to new cgroup. It should be
2201 * done by a caller(__mem_cgroup_try_charge would be usefull). If @uncharge is
2202 * true, this function does "uncharge" from old cgroup, but it doesn't if
2203 * @uncharge is false, so a caller should do "uncharge".
2205 static int mem_cgroup_move_account(struct page *page, struct page_cgroup *pc,
2206 struct mem_cgroup *from, struct mem_cgroup *to,
2207 bool uncharge, int charge_size)
2209 int nr_pages = charge_size >> PAGE_SHIFT;
2210 unsigned long flags;
2213 VM_BUG_ON(from == to);
2214 VM_BUG_ON(PageLRU(page));
2216 * The page is isolated from LRU. So, collapse function
2217 * will not handle this page. But page splitting can happen.
2218 * Do this check under compound_page_lock(). The caller should
2222 if (charge_size > PAGE_SIZE && !PageTransHuge(page))
2225 lock_page_cgroup(pc);
2228 if (!PageCgroupUsed(pc) || pc->mem_cgroup != from)
2231 move_lock_page_cgroup(pc, &flags);
2233 if (PageCgroupFileMapped(pc)) {
2234 /* Update mapped_file data for mem_cgroup */
2236 __this_cpu_dec(from->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]);
2237 __this_cpu_inc(to->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]);
2240 mem_cgroup_charge_statistics(from, PageCgroupCache(pc), -nr_pages);
2242 /* This is not "cancel", but cancel_charge does all we need. */
2243 __mem_cgroup_cancel_charge(from, nr_pages);
2245 /* caller should have done css_get */
2246 pc->mem_cgroup = to;
2247 mem_cgroup_charge_statistics(to, PageCgroupCache(pc), nr_pages);
2249 * We charges against "to" which may not have any tasks. Then, "to"
2250 * can be under rmdir(). But in current implementation, caller of
2251 * this function is just force_empty() and move charge, so it's
2252 * garanteed that "to" is never removed. So, we don't check rmdir
2255 move_unlock_page_cgroup(pc, &flags);
2258 unlock_page_cgroup(pc);
2262 memcg_check_events(to, page);
2263 memcg_check_events(from, page);
2269 * move charges to its parent.
2272 static int mem_cgroup_move_parent(struct page *page,
2273 struct page_cgroup *pc,
2274 struct mem_cgroup *child,
2277 struct cgroup *cg = child->css.cgroup;
2278 struct cgroup *pcg = cg->parent;
2279 struct mem_cgroup *parent;
2280 int page_size = PAGE_SIZE;
2281 unsigned long flags;
2289 if (!get_page_unless_zero(page))
2291 if (isolate_lru_page(page))
2294 if (PageTransHuge(page))
2295 page_size = HPAGE_SIZE;
2297 parent = mem_cgroup_from_cont(pcg);
2298 ret = __mem_cgroup_try_charge(NULL, gfp_mask,
2299 &parent, false, page_size);
2303 if (page_size > PAGE_SIZE)
2304 flags = compound_lock_irqsave(page);
2306 ret = mem_cgroup_move_account(page, pc, child, parent, true, page_size);
2308 __mem_cgroup_cancel_charge(parent, page_size >> PAGE_SHIFT);
2310 if (page_size > PAGE_SIZE)
2311 compound_unlock_irqrestore(page, flags);
2313 putback_lru_page(page);
2321 * Charge the memory controller for page usage.
2323 * 0 if the charge was successful
2324 * < 0 if the cgroup is over its limit
2326 static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm,
2327 gfp_t gfp_mask, enum charge_type ctype)
2329 struct mem_cgroup *mem = NULL;
2330 int page_size = PAGE_SIZE;
2331 struct page_cgroup *pc;
2335 if (PageTransHuge(page)) {
2336 page_size <<= compound_order(page);
2337 VM_BUG_ON(!PageTransHuge(page));
2339 * Never OOM-kill a process for a huge page. The
2340 * fault handler will fall back to regular pages.
2345 pc = lookup_page_cgroup(page);
2346 BUG_ON(!pc); /* XXX: remove this and move pc lookup into commit */
2348 ret = __mem_cgroup_try_charge(mm, gfp_mask, &mem, oom, page_size);
2352 __mem_cgroup_commit_charge(mem, page, pc, ctype, page_size);
2356 int mem_cgroup_newpage_charge(struct page *page,
2357 struct mm_struct *mm, gfp_t gfp_mask)
2359 if (mem_cgroup_disabled())
2362 * If already mapped, we don't have to account.
2363 * If page cache, page->mapping has address_space.
2364 * But page->mapping may have out-of-use anon_vma pointer,
2365 * detecit it by PageAnon() check. newly-mapped-anon's page->mapping
2368 if (page_mapped(page) || (page->mapping && !PageAnon(page)))
2372 return mem_cgroup_charge_common(page, mm, gfp_mask,
2373 MEM_CGROUP_CHARGE_TYPE_MAPPED);
2377 __mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr,
2378 enum charge_type ctype);
2380 int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
2385 if (mem_cgroup_disabled())
2387 if (PageCompound(page))
2390 * Corner case handling. This is called from add_to_page_cache()
2391 * in usual. But some FS (shmem) precharges this page before calling it
2392 * and call add_to_page_cache() with GFP_NOWAIT.
2394 * For GFP_NOWAIT case, the page may be pre-charged before calling
2395 * add_to_page_cache(). (See shmem.c) check it here and avoid to call
2396 * charge twice. (It works but has to pay a bit larger cost.)
2397 * And when the page is SwapCache, it should take swap information
2398 * into account. This is under lock_page() now.
2400 if (!(gfp_mask & __GFP_WAIT)) {
2401 struct page_cgroup *pc;
2403 pc = lookup_page_cgroup(page);
2406 lock_page_cgroup(pc);
2407 if (PageCgroupUsed(pc)) {
2408 unlock_page_cgroup(pc);
2411 unlock_page_cgroup(pc);
2417 if (page_is_file_cache(page))
2418 return mem_cgroup_charge_common(page, mm, gfp_mask,
2419 MEM_CGROUP_CHARGE_TYPE_CACHE);
2422 if (PageSwapCache(page)) {
2423 struct mem_cgroup *mem;
2425 ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &mem);
2427 __mem_cgroup_commit_charge_swapin(page, mem,
2428 MEM_CGROUP_CHARGE_TYPE_SHMEM);
2430 ret = mem_cgroup_charge_common(page, mm, gfp_mask,
2431 MEM_CGROUP_CHARGE_TYPE_SHMEM);
2437 * While swap-in, try_charge -> commit or cancel, the page is locked.
2438 * And when try_charge() successfully returns, one refcnt to memcg without
2439 * struct page_cgroup is acquired. This refcnt will be consumed by
2440 * "commit()" or removed by "cancel()"
2442 int mem_cgroup_try_charge_swapin(struct mm_struct *mm,
2444 gfp_t mask, struct mem_cgroup **ptr)
2446 struct mem_cgroup *mem;
2451 if (mem_cgroup_disabled())
2454 if (!do_swap_account)
2457 * A racing thread's fault, or swapoff, may have already updated
2458 * the pte, and even removed page from swap cache: in those cases
2459 * do_swap_page()'s pte_same() test will fail; but there's also a
2460 * KSM case which does need to charge the page.
2462 if (!PageSwapCache(page))
2464 mem = try_get_mem_cgroup_from_page(page);
2468 ret = __mem_cgroup_try_charge(NULL, mask, ptr, true, PAGE_SIZE);
2474 return __mem_cgroup_try_charge(mm, mask, ptr, true, PAGE_SIZE);
2478 __mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr,
2479 enum charge_type ctype)
2481 struct page_cgroup *pc;
2483 if (mem_cgroup_disabled())
2487 cgroup_exclude_rmdir(&ptr->css);
2488 pc = lookup_page_cgroup(page);
2489 mem_cgroup_lru_del_before_commit_swapcache(page);
2490 __mem_cgroup_commit_charge(ptr, page, pc, ctype, PAGE_SIZE);
2491 mem_cgroup_lru_add_after_commit_swapcache(page);
2493 * Now swap is on-memory. This means this page may be
2494 * counted both as mem and swap....double count.
2495 * Fix it by uncharging from memsw. Basically, this SwapCache is stable
2496 * under lock_page(). But in do_swap_page()::memory.c, reuse_swap_page()
2497 * may call delete_from_swap_cache() before reach here.
2499 if (do_swap_account && PageSwapCache(page)) {
2500 swp_entry_t ent = {.val = page_private(page)};
2502 struct mem_cgroup *memcg;
2504 id = swap_cgroup_record(ent, 0);
2506 memcg = mem_cgroup_lookup(id);
2509 * This recorded memcg can be obsolete one. So, avoid
2510 * calling css_tryget
2512 if (!mem_cgroup_is_root(memcg))
2513 res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
2514 mem_cgroup_swap_statistics(memcg, false);
2515 mem_cgroup_put(memcg);
2520 * At swapin, we may charge account against cgroup which has no tasks.
2521 * So, rmdir()->pre_destroy() can be called while we do this charge.
2522 * In that case, we need to call pre_destroy() again. check it here.
2524 cgroup_release_and_wakeup_rmdir(&ptr->css);
2527 void mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr)
2529 __mem_cgroup_commit_charge_swapin(page, ptr,
2530 MEM_CGROUP_CHARGE_TYPE_MAPPED);
2533 void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *mem)
2535 if (mem_cgroup_disabled())
2539 __mem_cgroup_cancel_charge(mem, 1);
2543 __do_uncharge(struct mem_cgroup *mem, const enum charge_type ctype,
2546 struct memcg_batch_info *batch = NULL;
2547 bool uncharge_memsw = true;
2548 /* If swapout, usage of swap doesn't decrease */
2549 if (!do_swap_account || ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT)
2550 uncharge_memsw = false;
2552 batch = ¤t->memcg_batch;
2554 * In usual, we do css_get() when we remember memcg pointer.
2555 * But in this case, we keep res->usage until end of a series of
2556 * uncharges. Then, it's ok to ignore memcg's refcnt.
2561 * do_batch > 0 when unmapping pages or inode invalidate/truncate.
2562 * In those cases, all pages freed continously can be expected to be in
2563 * the same cgroup and we have chance to coalesce uncharges.
2564 * But we do uncharge one by one if this is killed by OOM(TIF_MEMDIE)
2565 * because we want to do uncharge as soon as possible.
2568 if (!batch->do_batch || test_thread_flag(TIF_MEMDIE))
2569 goto direct_uncharge;
2571 if (page_size != PAGE_SIZE)
2572 goto direct_uncharge;
2575 * In typical case, batch->memcg == mem. This means we can
2576 * merge a series of uncharges to an uncharge of res_counter.
2577 * If not, we uncharge res_counter ony by one.
2579 if (batch->memcg != mem)
2580 goto direct_uncharge;
2581 /* remember freed charge and uncharge it later */
2582 batch->bytes += PAGE_SIZE;
2584 batch->memsw_bytes += PAGE_SIZE;
2587 res_counter_uncharge(&mem->res, page_size);
2589 res_counter_uncharge(&mem->memsw, page_size);
2590 if (unlikely(batch->memcg != mem))
2591 memcg_oom_recover(mem);
2596 * uncharge if !page_mapped(page)
2598 static struct mem_cgroup *
2599 __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
2602 struct page_cgroup *pc;
2603 struct mem_cgroup *mem = NULL;
2604 int page_size = PAGE_SIZE;
2606 if (mem_cgroup_disabled())
2609 if (PageSwapCache(page))
2612 if (PageTransHuge(page)) {
2613 page_size <<= compound_order(page);
2614 VM_BUG_ON(!PageTransHuge(page));
2617 count = page_size >> PAGE_SHIFT;
2619 * Check if our page_cgroup is valid
2621 pc = lookup_page_cgroup(page);
2622 if (unlikely(!pc || !PageCgroupUsed(pc)))
2625 lock_page_cgroup(pc);
2627 mem = pc->mem_cgroup;
2629 if (!PageCgroupUsed(pc))
2633 case MEM_CGROUP_CHARGE_TYPE_MAPPED:
2634 case MEM_CGROUP_CHARGE_TYPE_DROP:
2635 /* See mem_cgroup_prepare_migration() */
2636 if (page_mapped(page) || PageCgroupMigration(pc))
2639 case MEM_CGROUP_CHARGE_TYPE_SWAPOUT:
2640 if (!PageAnon(page)) { /* Shared memory */
2641 if (page->mapping && !page_is_file_cache(page))
2643 } else if (page_mapped(page)) /* Anon */
2650 mem_cgroup_charge_statistics(mem, PageCgroupCache(pc), -count);
2652 ClearPageCgroupUsed(pc);
2654 * pc->mem_cgroup is not cleared here. It will be accessed when it's
2655 * freed from LRU. This is safe because uncharged page is expected not
2656 * to be reused (freed soon). Exception is SwapCache, it's handled by
2657 * special functions.
2660 unlock_page_cgroup(pc);
2662 * even after unlock, we have mem->res.usage here and this memcg
2663 * will never be freed.
2665 memcg_check_events(mem, page);
2666 if (do_swap_account && ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT) {
2667 mem_cgroup_swap_statistics(mem, true);
2668 mem_cgroup_get(mem);
2670 if (!mem_cgroup_is_root(mem))
2671 __do_uncharge(mem, ctype, page_size);
2676 unlock_page_cgroup(pc);
2680 void mem_cgroup_uncharge_page(struct page *page)
2683 if (page_mapped(page))
2685 if (page->mapping && !PageAnon(page))
2687 __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_MAPPED);
2690 void mem_cgroup_uncharge_cache_page(struct page *page)
2692 VM_BUG_ON(page_mapped(page));
2693 VM_BUG_ON(page->mapping);
2694 __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE);
2698 * Batch_start/batch_end is called in unmap_page_range/invlidate/trucate.
2699 * In that cases, pages are freed continuously and we can expect pages
2700 * are in the same memcg. All these calls itself limits the number of
2701 * pages freed at once, then uncharge_start/end() is called properly.
2702 * This may be called prural(2) times in a context,
2705 void mem_cgroup_uncharge_start(void)
2707 current->memcg_batch.do_batch++;
2708 /* We can do nest. */
2709 if (current->memcg_batch.do_batch == 1) {
2710 current->memcg_batch.memcg = NULL;
2711 current->memcg_batch.bytes = 0;
2712 current->memcg_batch.memsw_bytes = 0;
2716 void mem_cgroup_uncharge_end(void)
2718 struct memcg_batch_info *batch = ¤t->memcg_batch;
2720 if (!batch->do_batch)
2724 if (batch->do_batch) /* If stacked, do nothing. */
2730 * This "batch->memcg" is valid without any css_get/put etc...
2731 * bacause we hide charges behind us.
2734 res_counter_uncharge(&batch->memcg->res, batch->bytes);
2735 if (batch->memsw_bytes)
2736 res_counter_uncharge(&batch->memcg->memsw, batch->memsw_bytes);
2737 memcg_oom_recover(batch->memcg);
2738 /* forget this pointer (for sanity check) */
2739 batch->memcg = NULL;
2744 * called after __delete_from_swap_cache() and drop "page" account.
2745 * memcg information is recorded to swap_cgroup of "ent"
2748 mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout)
2750 struct mem_cgroup *memcg;
2751 int ctype = MEM_CGROUP_CHARGE_TYPE_SWAPOUT;
2753 if (!swapout) /* this was a swap cache but the swap is unused ! */
2754 ctype = MEM_CGROUP_CHARGE_TYPE_DROP;
2756 memcg = __mem_cgroup_uncharge_common(page, ctype);
2759 * record memcg information, if swapout && memcg != NULL,
2760 * mem_cgroup_get() was called in uncharge().
2762 if (do_swap_account && swapout && memcg)
2763 swap_cgroup_record(ent, css_id(&memcg->css));
2767 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
2769 * called from swap_entry_free(). remove record in swap_cgroup and
2770 * uncharge "memsw" account.
2772 void mem_cgroup_uncharge_swap(swp_entry_t ent)
2774 struct mem_cgroup *memcg;
2777 if (!do_swap_account)
2780 id = swap_cgroup_record(ent, 0);
2782 memcg = mem_cgroup_lookup(id);
2785 * We uncharge this because swap is freed.
2786 * This memcg can be obsolete one. We avoid calling css_tryget
2788 if (!mem_cgroup_is_root(memcg))
2789 res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
2790 mem_cgroup_swap_statistics(memcg, false);
2791 mem_cgroup_put(memcg);
2797 * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record.
2798 * @entry: swap entry to be moved
2799 * @from: mem_cgroup which the entry is moved from
2800 * @to: mem_cgroup which the entry is moved to
2801 * @need_fixup: whether we should fixup res_counters and refcounts.
2803 * It succeeds only when the swap_cgroup's record for this entry is the same
2804 * as the mem_cgroup's id of @from.
2806 * Returns 0 on success, -EINVAL on failure.
2808 * The caller must have charged to @to, IOW, called res_counter_charge() about
2809 * both res and memsw, and called css_get().
2811 static int mem_cgroup_move_swap_account(swp_entry_t entry,
2812 struct mem_cgroup *from, struct mem_cgroup *to, bool need_fixup)
2814 unsigned short old_id, new_id;
2816 old_id = css_id(&from->css);
2817 new_id = css_id(&to->css);
2819 if (swap_cgroup_cmpxchg(entry, old_id, new_id) == old_id) {
2820 mem_cgroup_swap_statistics(from, false);
2821 mem_cgroup_swap_statistics(to, true);
2823 * This function is only called from task migration context now.
2824 * It postpones res_counter and refcount handling till the end
2825 * of task migration(mem_cgroup_clear_mc()) for performance
2826 * improvement. But we cannot postpone mem_cgroup_get(to)
2827 * because if the process that has been moved to @to does
2828 * swap-in, the refcount of @to might be decreased to 0.
2832 if (!mem_cgroup_is_root(from))
2833 res_counter_uncharge(&from->memsw, PAGE_SIZE);
2834 mem_cgroup_put(from);
2836 * we charged both to->res and to->memsw, so we should
2839 if (!mem_cgroup_is_root(to))
2840 res_counter_uncharge(&to->res, PAGE_SIZE);
2847 static inline int mem_cgroup_move_swap_account(swp_entry_t entry,
2848 struct mem_cgroup *from, struct mem_cgroup *to, bool need_fixup)
2855 * Before starting migration, account PAGE_SIZE to mem_cgroup that the old
2858 int mem_cgroup_prepare_migration(struct page *page,
2859 struct page *newpage, struct mem_cgroup **ptr, gfp_t gfp_mask)
2861 struct page_cgroup *pc;
2862 struct mem_cgroup *mem = NULL;
2863 enum charge_type ctype;
2868 VM_BUG_ON(PageTransHuge(page));
2869 if (mem_cgroup_disabled())
2872 pc = lookup_page_cgroup(page);
2873 lock_page_cgroup(pc);
2874 if (PageCgroupUsed(pc)) {
2875 mem = pc->mem_cgroup;
2878 * At migrating an anonymous page, its mapcount goes down
2879 * to 0 and uncharge() will be called. But, even if it's fully
2880 * unmapped, migration may fail and this page has to be
2881 * charged again. We set MIGRATION flag here and delay uncharge
2882 * until end_migration() is called
2884 * Corner Case Thinking
2886 * When the old page was mapped as Anon and it's unmap-and-freed
2887 * while migration was ongoing.
2888 * If unmap finds the old page, uncharge() of it will be delayed
2889 * until end_migration(). If unmap finds a new page, it's
2890 * uncharged when it make mapcount to be 1->0. If unmap code
2891 * finds swap_migration_entry, the new page will not be mapped
2892 * and end_migration() will find it(mapcount==0).
2895 * When the old page was mapped but migraion fails, the kernel
2896 * remaps it. A charge for it is kept by MIGRATION flag even
2897 * if mapcount goes down to 0. We can do remap successfully
2898 * without charging it again.
2901 * The "old" page is under lock_page() until the end of
2902 * migration, so, the old page itself will not be swapped-out.
2903 * If the new page is swapped out before end_migraton, our
2904 * hook to usual swap-out path will catch the event.
2907 SetPageCgroupMigration(pc);
2909 unlock_page_cgroup(pc);
2911 * If the page is not charged at this point,
2918 ret = __mem_cgroup_try_charge(NULL, gfp_mask, ptr, false, PAGE_SIZE);
2919 css_put(&mem->css);/* drop extra refcnt */
2920 if (ret || *ptr == NULL) {
2921 if (PageAnon(page)) {
2922 lock_page_cgroup(pc);
2923 ClearPageCgroupMigration(pc);
2924 unlock_page_cgroup(pc);
2926 * The old page may be fully unmapped while we kept it.
2928 mem_cgroup_uncharge_page(page);
2933 * We charge new page before it's used/mapped. So, even if unlock_page()
2934 * is called before end_migration, we can catch all events on this new
2935 * page. In the case new page is migrated but not remapped, new page's
2936 * mapcount will be finally 0 and we call uncharge in end_migration().
2938 pc = lookup_page_cgroup(newpage);
2940 ctype = MEM_CGROUP_CHARGE_TYPE_MAPPED;
2941 else if (page_is_file_cache(page))
2942 ctype = MEM_CGROUP_CHARGE_TYPE_CACHE;
2944 ctype = MEM_CGROUP_CHARGE_TYPE_SHMEM;
2945 __mem_cgroup_commit_charge(mem, page, pc, ctype, PAGE_SIZE);
2949 /* remove redundant charge if migration failed*/
2950 void mem_cgroup_end_migration(struct mem_cgroup *mem,
2951 struct page *oldpage, struct page *newpage, bool migration_ok)
2953 struct page *used, *unused;
2954 struct page_cgroup *pc;
2958 /* blocks rmdir() */
2959 cgroup_exclude_rmdir(&mem->css);
2960 if (!migration_ok) {
2968 * We disallowed uncharge of pages under migration because mapcount
2969 * of the page goes down to zero, temporarly.
2970 * Clear the flag and check the page should be charged.
2972 pc = lookup_page_cgroup(oldpage);
2973 lock_page_cgroup(pc);
2974 ClearPageCgroupMigration(pc);
2975 unlock_page_cgroup(pc);
2977 __mem_cgroup_uncharge_common(unused, MEM_CGROUP_CHARGE_TYPE_FORCE);
2980 * If a page is a file cache, radix-tree replacement is very atomic
2981 * and we can skip this check. When it was an Anon page, its mapcount
2982 * goes down to 0. But because we added MIGRATION flage, it's not
2983 * uncharged yet. There are several case but page->mapcount check
2984 * and USED bit check in mem_cgroup_uncharge_page() will do enough
2985 * check. (see prepare_charge() also)
2988 mem_cgroup_uncharge_page(used);
2990 * At migration, we may charge account against cgroup which has no
2992 * So, rmdir()->pre_destroy() can be called while we do this charge.
2993 * In that case, we need to call pre_destroy() again. check it here.
2995 cgroup_release_and_wakeup_rmdir(&mem->css);
2999 * A call to try to shrink memory usage on charge failure at shmem's swapin.
3000 * Calling hierarchical_reclaim is not enough because we should update
3001 * last_oom_jiffies to prevent pagefault_out_of_memory from invoking global OOM.
3002 * Moreover considering hierarchy, we should reclaim from the mem_over_limit,
3003 * not from the memcg which this page would be charged to.
3004 * try_charge_swapin does all of these works properly.
3006 int mem_cgroup_shmem_charge_fallback(struct page *page,
3007 struct mm_struct *mm,
3010 struct mem_cgroup *mem;
3013 if (mem_cgroup_disabled())
3016 ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &mem);
3018 mem_cgroup_cancel_charge_swapin(mem); /* it does !mem check */
3023 #ifdef CONFIG_DEBUG_VM
3024 static struct page_cgroup *lookup_page_cgroup_used(struct page *page)
3026 struct page_cgroup *pc;
3028 pc = lookup_page_cgroup(page);
3029 if (likely(pc) && PageCgroupUsed(pc))
3034 bool mem_cgroup_bad_page_check(struct page *page)
3036 if (mem_cgroup_disabled())
3039 return lookup_page_cgroup_used(page) != NULL;
3042 void mem_cgroup_print_bad_page(struct page *page)
3044 struct page_cgroup *pc;
3046 pc = lookup_page_cgroup_used(page);
3051 printk(KERN_ALERT "pc:%p pc->flags:%lx pc->mem_cgroup:%p",
3052 pc, pc->flags, pc->mem_cgroup);
3054 path = kmalloc(PATH_MAX, GFP_KERNEL);
3057 ret = cgroup_path(pc->mem_cgroup->css.cgroup,
3062 printk(KERN_CONT "(%s)\n",
3063 (ret < 0) ? "cannot get the path" : path);
3069 static DEFINE_MUTEX(set_limit_mutex);
3071 static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
3072 unsigned long long val)
3075 u64 memswlimit, memlimit;
3077 int children = mem_cgroup_count_children(memcg);
3078 u64 curusage, oldusage;
3082 * For keeping hierarchical_reclaim simple, how long we should retry
3083 * is depends on callers. We set our retry-count to be function
3084 * of # of children which we should visit in this loop.
3086 retry_count = MEM_CGROUP_RECLAIM_RETRIES * children;
3088 oldusage = res_counter_read_u64(&memcg->res, RES_USAGE);
3091 while (retry_count) {
3092 if (signal_pending(current)) {
3097 * Rather than hide all in some function, I do this in
3098 * open coded manner. You see what this really does.
3099 * We have to guarantee mem->res.limit < mem->memsw.limit.
3101 mutex_lock(&set_limit_mutex);
3102 memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
3103 if (memswlimit < val) {
3105 mutex_unlock(&set_limit_mutex);
3109 memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT);
3113 ret = res_counter_set_limit(&memcg->res, val);
3115 if (memswlimit == val)
3116 memcg->memsw_is_minimum = true;
3118 memcg->memsw_is_minimum = false;
3120 mutex_unlock(&set_limit_mutex);
3125 mem_cgroup_hierarchical_reclaim(memcg, NULL, GFP_KERNEL,
3126 MEM_CGROUP_RECLAIM_SHRINK);
3127 curusage = res_counter_read_u64(&memcg->res, RES_USAGE);
3128 /* Usage is reduced ? */
3129 if (curusage >= oldusage)
3132 oldusage = curusage;
3134 if (!ret && enlarge)
3135 memcg_oom_recover(memcg);
3140 static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
3141 unsigned long long val)
3144 u64 memlimit, memswlimit, oldusage, curusage;
3145 int children = mem_cgroup_count_children(memcg);
3149 /* see mem_cgroup_resize_res_limit */
3150 retry_count = children * MEM_CGROUP_RECLAIM_RETRIES;
3151 oldusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
3152 while (retry_count) {
3153 if (signal_pending(current)) {
3158 * Rather than hide all in some function, I do this in
3159 * open coded manner. You see what this really does.
3160 * We have to guarantee mem->res.limit < mem->memsw.limit.
3162 mutex_lock(&set_limit_mutex);
3163 memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT);
3164 if (memlimit > val) {
3166 mutex_unlock(&set_limit_mutex);
3169 memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
3170 if (memswlimit < val)
3172 ret = res_counter_set_limit(&memcg->memsw, val);
3174 if (memlimit == val)
3175 memcg->memsw_is_minimum = true;
3177 memcg->memsw_is_minimum = false;
3179 mutex_unlock(&set_limit_mutex);
3184 mem_cgroup_hierarchical_reclaim(memcg, NULL, GFP_KERNEL,
3185 MEM_CGROUP_RECLAIM_NOSWAP |
3186 MEM_CGROUP_RECLAIM_SHRINK);
3187 curusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
3188 /* Usage is reduced ? */
3189 if (curusage >= oldusage)
3192 oldusage = curusage;
3194 if (!ret && enlarge)
3195 memcg_oom_recover(memcg);
3199 unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
3202 unsigned long nr_reclaimed = 0;
3203 struct mem_cgroup_per_zone *mz, *next_mz = NULL;
3204 unsigned long reclaimed;
3206 struct mem_cgroup_tree_per_zone *mctz;
3207 unsigned long long excess;
3212 mctz = soft_limit_tree_node_zone(zone_to_nid(zone), zone_idx(zone));
3214 * This loop can run a while, specially if mem_cgroup's continuously
3215 * keep exceeding their soft limit and putting the system under
3222 mz = mem_cgroup_largest_soft_limit_node(mctz);
3226 reclaimed = mem_cgroup_hierarchical_reclaim(mz->mem, zone,
3228 MEM_CGROUP_RECLAIM_SOFT);
3229 nr_reclaimed += reclaimed;
3230 spin_lock(&mctz->lock);
3233 * If we failed to reclaim anything from this memory cgroup
3234 * it is time to move on to the next cgroup
3240 * Loop until we find yet another one.
3242 * By the time we get the soft_limit lock
3243 * again, someone might have aded the
3244 * group back on the RB tree. Iterate to
3245 * make sure we get a different mem.
3246 * mem_cgroup_largest_soft_limit_node returns
3247 * NULL if no other cgroup is present on
3251 __mem_cgroup_largest_soft_limit_node(mctz);
3252 if (next_mz == mz) {
3253 css_put(&next_mz->mem->css);
3255 } else /* next_mz == NULL or other memcg */
3259 __mem_cgroup_remove_exceeded(mz->mem, mz, mctz);
3260 excess = res_counter_soft_limit_excess(&mz->mem->res);
3262 * One school of thought says that we should not add
3263 * back the node to the tree if reclaim returns 0.
3264 * But our reclaim could return 0, simply because due
3265 * to priority we are exposing a smaller subset of
3266 * memory to reclaim from. Consider this as a longer
3269 /* If excess == 0, no tree ops */
3270 __mem_cgroup_insert_exceeded(mz->mem, mz, mctz, excess);
3271 spin_unlock(&mctz->lock);
3272 css_put(&mz->mem->css);
3275 * Could not reclaim anything and there are no more
3276 * mem cgroups to try or we seem to be looping without
3277 * reclaiming anything.
3279 if (!nr_reclaimed &&
3281 loop > MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS))
3283 } while (!nr_reclaimed);
3285 css_put(&next_mz->mem->css);
3286 return nr_reclaimed;
3290 * This routine traverse page_cgroup in given list and drop them all.
3291 * *And* this routine doesn't reclaim page itself, just removes page_cgroup.
3293 static int mem_cgroup_force_empty_list(struct mem_cgroup *mem,
3294 int node, int zid, enum lru_list lru)
3297 struct mem_cgroup_per_zone *mz;
3298 struct page_cgroup *pc, *busy;
3299 unsigned long flags, loop;
3300 struct list_head *list;
3303 zone = &NODE_DATA(node)->node_zones[zid];
3304 mz = mem_cgroup_zoneinfo(mem, node, zid);
3305 list = &mz->lists[lru];
3307 loop = MEM_CGROUP_ZSTAT(mz, lru);
3308 /* give some margin against EBUSY etc...*/
3315 spin_lock_irqsave(&zone->lru_lock, flags);
3316 if (list_empty(list)) {
3317 spin_unlock_irqrestore(&zone->lru_lock, flags);
3320 pc = list_entry(list->prev, struct page_cgroup, lru);
3322 list_move(&pc->lru, list);
3324 spin_unlock_irqrestore(&zone->lru_lock, flags);
3327 spin_unlock_irqrestore(&zone->lru_lock, flags);
3329 page = lookup_cgroup_page(pc);
3331 ret = mem_cgroup_move_parent(page, pc, mem, GFP_KERNEL);
3335 if (ret == -EBUSY || ret == -EINVAL) {
3336 /* found lock contention or "pc" is obsolete. */
3343 if (!ret && !list_empty(list))
3349 * make mem_cgroup's charge to be 0 if there is no task.
3350 * This enables deleting this mem_cgroup.
3352 static int mem_cgroup_force_empty(struct mem_cgroup *mem, bool free_all)
3355 int node, zid, shrink;
3356 int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
3357 struct cgroup *cgrp = mem->css.cgroup;
3362 /* should free all ? */
3368 if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children))
3371 if (signal_pending(current))
3373 /* This is for making all *used* pages to be on LRU. */
3374 lru_add_drain_all();
3375 drain_all_stock_sync();
3377 mem_cgroup_start_move(mem);
3378 for_each_node_state(node, N_HIGH_MEMORY) {
3379 for (zid = 0; !ret && zid < MAX_NR_ZONES; zid++) {
3382 ret = mem_cgroup_force_empty_list(mem,
3391 mem_cgroup_end_move(mem);
3392 memcg_oom_recover(mem);
3393 /* it seems parent cgroup doesn't have enough mem */
3397 /* "ret" should also be checked to ensure all lists are empty. */
3398 } while (mem->res.usage > 0 || ret);
3404 /* returns EBUSY if there is a task or if we come here twice. */
3405 if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children) || shrink) {
3409 /* we call try-to-free pages for make this cgroup empty */
3410 lru_add_drain_all();
3411 /* try to free all pages in this cgroup */
3413 while (nr_retries && mem->res.usage > 0) {
3416 if (signal_pending(current)) {
3420 progress = try_to_free_mem_cgroup_pages(mem, GFP_KERNEL,
3421 false, get_swappiness(mem));
3424 /* maybe some writeback is necessary */
3425 congestion_wait(BLK_RW_ASYNC, HZ/10);
3430 /* try move_account...there may be some *locked* pages. */
3434 int mem_cgroup_force_empty_write(struct cgroup *cont, unsigned int event)
3436 return mem_cgroup_force_empty(mem_cgroup_from_cont(cont), true);
3440 static u64 mem_cgroup_hierarchy_read(struct cgroup *cont, struct cftype *cft)
3442 return mem_cgroup_from_cont(cont)->use_hierarchy;
3445 static int mem_cgroup_hierarchy_write(struct cgroup *cont, struct cftype *cft,
3449 struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
3450 struct cgroup *parent = cont->parent;
3451 struct mem_cgroup *parent_mem = NULL;
3454 parent_mem = mem_cgroup_from_cont(parent);
3458 * If parent's use_hierarchy is set, we can't make any modifications
3459 * in the child subtrees. If it is unset, then the change can
3460 * occur, provided the current cgroup has no children.
3462 * For the root cgroup, parent_mem is NULL, we allow value to be
3463 * set if there are no children.
3465 if ((!parent_mem || !parent_mem->use_hierarchy) &&
3466 (val == 1 || val == 0)) {
3467 if (list_empty(&cont->children))
3468 mem->use_hierarchy = val;
3479 static u64 mem_cgroup_get_recursive_idx_stat(struct mem_cgroup *mem,
3480 enum mem_cgroup_stat_index idx)
3482 struct mem_cgroup *iter;
3485 /* each per cpu's value can be minus.Then, use s64 */
3486 for_each_mem_cgroup_tree(iter, mem)
3487 val += mem_cgroup_read_stat(iter, idx);
3489 if (val < 0) /* race ? */
3494 static inline u64 mem_cgroup_usage(struct mem_cgroup *mem, bool swap)
3498 if (!mem_cgroup_is_root(mem)) {
3500 return res_counter_read_u64(&mem->res, RES_USAGE);
3502 return res_counter_read_u64(&mem->memsw, RES_USAGE);
3505 val = mem_cgroup_get_recursive_idx_stat(mem, MEM_CGROUP_STAT_CACHE);
3506 val += mem_cgroup_get_recursive_idx_stat(mem, MEM_CGROUP_STAT_RSS);
3509 val += mem_cgroup_get_recursive_idx_stat(mem,
3510 MEM_CGROUP_STAT_SWAPOUT);
3512 return val << PAGE_SHIFT;
3515 static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft)
3517 struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
3521 type = MEMFILE_TYPE(cft->private);
3522 name = MEMFILE_ATTR(cft->private);
3525 if (name == RES_USAGE)
3526 val = mem_cgroup_usage(mem, false);
3528 val = res_counter_read_u64(&mem->res, name);
3531 if (name == RES_USAGE)
3532 val = mem_cgroup_usage(mem, true);
3534 val = res_counter_read_u64(&mem->memsw, name);
3543 * The user of this function is...
3546 static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
3549 struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
3551 unsigned long long val;
3554 type = MEMFILE_TYPE(cft->private);
3555 name = MEMFILE_ATTR(cft->private);
3558 if (mem_cgroup_is_root(memcg)) { /* Can't set limit on root */
3562 /* This function does all necessary parse...reuse it */
3563 ret = res_counter_memparse_write_strategy(buffer, &val);
3567 ret = mem_cgroup_resize_limit(memcg, val);
3569 ret = mem_cgroup_resize_memsw_limit(memcg, val);
3571 case RES_SOFT_LIMIT:
3572 ret = res_counter_memparse_write_strategy(buffer, &val);
3576 * For memsw, soft limits are hard to implement in terms
3577 * of semantics, for now, we support soft limits for
3578 * control without swap
3581 ret = res_counter_set_soft_limit(&memcg->res, val);
3586 ret = -EINVAL; /* should be BUG() ? */
3592 static void memcg_get_hierarchical_limit(struct mem_cgroup *memcg,
3593 unsigned long long *mem_limit, unsigned long long *memsw_limit)
3595 struct cgroup *cgroup;
3596 unsigned long long min_limit, min_memsw_limit, tmp;
3598 min_limit = res_counter_read_u64(&memcg->res, RES_LIMIT);
3599 min_memsw_limit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
3600 cgroup = memcg->css.cgroup;
3601 if (!memcg->use_hierarchy)
3604 while (cgroup->parent) {
3605 cgroup = cgroup->parent;
3606 memcg = mem_cgroup_from_cont(cgroup);
3607 if (!memcg->use_hierarchy)
3609 tmp = res_counter_read_u64(&memcg->res, RES_LIMIT);
3610 min_limit = min(min_limit, tmp);
3611 tmp = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
3612 min_memsw_limit = min(min_memsw_limit, tmp);
3615 *mem_limit = min_limit;
3616 *memsw_limit = min_memsw_limit;
3620 static int mem_cgroup_reset(struct cgroup *cont, unsigned int event)
3622 struct mem_cgroup *mem;
3625 mem = mem_cgroup_from_cont(cont);
3626 type = MEMFILE_TYPE(event);
3627 name = MEMFILE_ATTR(event);
3631 res_counter_reset_max(&mem->res);
3633 res_counter_reset_max(&mem->memsw);
3637 res_counter_reset_failcnt(&mem->res);
3639 res_counter_reset_failcnt(&mem->memsw);
3646 static u64 mem_cgroup_move_charge_read(struct cgroup *cgrp,
3649 return mem_cgroup_from_cont(cgrp)->move_charge_at_immigrate;
3653 static int mem_cgroup_move_charge_write(struct cgroup *cgrp,
3654 struct cftype *cft, u64 val)
3656 struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp);
3658 if (val >= (1 << NR_MOVE_TYPE))
3661 * We check this value several times in both in can_attach() and
3662 * attach(), so we need cgroup lock to prevent this value from being
3666 mem->move_charge_at_immigrate = val;
3672 static int mem_cgroup_move_charge_write(struct cgroup *cgrp,
3673 struct cftype *cft, u64 val)
3680 /* For read statistics */
3696 struct mcs_total_stat {
3697 s64 stat[NR_MCS_STAT];
3703 } memcg_stat_strings[NR_MCS_STAT] = {
3704 {"cache", "total_cache"},
3705 {"rss", "total_rss"},
3706 {"mapped_file", "total_mapped_file"},
3707 {"pgpgin", "total_pgpgin"},
3708 {"pgpgout", "total_pgpgout"},
3709 {"swap", "total_swap"},
3710 {"inactive_anon", "total_inactive_anon"},
3711 {"active_anon", "total_active_anon"},
3712 {"inactive_file", "total_inactive_file"},
3713 {"active_file", "total_active_file"},
3714 {"unevictable", "total_unevictable"}
3719 mem_cgroup_get_local_stat(struct mem_cgroup *mem, struct mcs_total_stat *s)
3724 val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_CACHE);
3725 s->stat[MCS_CACHE] += val * PAGE_SIZE;
3726 val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_RSS);
3727 s->stat[MCS_RSS] += val * PAGE_SIZE;
3728 val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_FILE_MAPPED);
3729 s->stat[MCS_FILE_MAPPED] += val * PAGE_SIZE;
3730 val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_PGPGIN_COUNT);
3731 s->stat[MCS_PGPGIN] += val;
3732 val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_PGPGOUT_COUNT);
3733 s->stat[MCS_PGPGOUT] += val;
3734 if (do_swap_account) {
3735 val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_SWAPOUT);
3736 s->stat[MCS_SWAP] += val * PAGE_SIZE;
3740 val = mem_cgroup_get_local_zonestat(mem, LRU_INACTIVE_ANON);
3741 s->stat[MCS_INACTIVE_ANON] += val * PAGE_SIZE;
3742 val = mem_cgroup_get_local_zonestat(mem, LRU_ACTIVE_ANON);
3743 s->stat[MCS_ACTIVE_ANON] += val * PAGE_SIZE;
3744 val = mem_cgroup_get_local_zonestat(mem, LRU_INACTIVE_FILE);
3745 s->stat[MCS_INACTIVE_FILE] += val * PAGE_SIZE;
3746 val = mem_cgroup_get_local_zonestat(mem, LRU_ACTIVE_FILE);
3747 s->stat[MCS_ACTIVE_FILE] += val * PAGE_SIZE;
3748 val = mem_cgroup_get_local_zonestat(mem, LRU_UNEVICTABLE);
3749 s->stat[MCS_UNEVICTABLE] += val * PAGE_SIZE;
3753 mem_cgroup_get_total_stat(struct mem_cgroup *mem, struct mcs_total_stat *s)
3755 struct mem_cgroup *iter;
3757 for_each_mem_cgroup_tree(iter, mem)
3758 mem_cgroup_get_local_stat(iter, s);
3761 static int mem_control_stat_show(struct cgroup *cont, struct cftype *cft,
3762 struct cgroup_map_cb *cb)
3764 struct mem_cgroup *mem_cont = mem_cgroup_from_cont(cont);
3765 struct mcs_total_stat mystat;
3768 memset(&mystat, 0, sizeof(mystat));
3769 mem_cgroup_get_local_stat(mem_cont, &mystat);
3771 for (i = 0; i < NR_MCS_STAT; i++) {
3772 if (i == MCS_SWAP && !do_swap_account)
3774 cb->fill(cb, memcg_stat_strings[i].local_name, mystat.stat[i]);
3777 /* Hierarchical information */
3779 unsigned long long limit, memsw_limit;
3780 memcg_get_hierarchical_limit(mem_cont, &limit, &memsw_limit);
3781 cb->fill(cb, "hierarchical_memory_limit", limit);
3782 if (do_swap_account)
3783 cb->fill(cb, "hierarchical_memsw_limit", memsw_limit);
3786 memset(&mystat, 0, sizeof(mystat));
3787 mem_cgroup_get_total_stat(mem_cont, &mystat);
3788 for (i = 0; i < NR_MCS_STAT; i++) {
3789 if (i == MCS_SWAP && !do_swap_account)
3791 cb->fill(cb, memcg_stat_strings[i].total_name, mystat.stat[i]);
3794 #ifdef CONFIG_DEBUG_VM
3795 cb->fill(cb, "inactive_ratio", calc_inactive_ratio(mem_cont, NULL));
3799 struct mem_cgroup_per_zone *mz;
3800 unsigned long recent_rotated[2] = {0, 0};
3801 unsigned long recent_scanned[2] = {0, 0};
3803 for_each_online_node(nid)
3804 for (zid = 0; zid < MAX_NR_ZONES; zid++) {
3805 mz = mem_cgroup_zoneinfo(mem_cont, nid, zid);
3807 recent_rotated[0] +=
3808 mz->reclaim_stat.recent_rotated[0];
3809 recent_rotated[1] +=
3810 mz->reclaim_stat.recent_rotated[1];
3811 recent_scanned[0] +=
3812 mz->reclaim_stat.recent_scanned[0];
3813 recent_scanned[1] +=
3814 mz->reclaim_stat.recent_scanned[1];
3816 cb->fill(cb, "recent_rotated_anon", recent_rotated[0]);
3817 cb->fill(cb, "recent_rotated_file", recent_rotated[1]);
3818 cb->fill(cb, "recent_scanned_anon", recent_scanned[0]);
3819 cb->fill(cb, "recent_scanned_file", recent_scanned[1]);
3826 static u64 mem_cgroup_swappiness_read(struct cgroup *cgrp, struct cftype *cft)
3828 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
3830 return get_swappiness(memcg);
3833 static int mem_cgroup_swappiness_write(struct cgroup *cgrp, struct cftype *cft,
3836 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
3837 struct mem_cgroup *parent;
3842 if (cgrp->parent == NULL)
3845 parent = mem_cgroup_from_cont(cgrp->parent);
3849 /* If under hierarchy, only empty-root can set this value */
3850 if ((parent->use_hierarchy) ||
3851 (memcg->use_hierarchy && !list_empty(&cgrp->children))) {
3856 memcg->swappiness = val;
3863 static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap)
3865 struct mem_cgroup_threshold_ary *t;
3871 t = rcu_dereference(memcg->thresholds.primary);
3873 t = rcu_dereference(memcg->memsw_thresholds.primary);
3878 usage = mem_cgroup_usage(memcg, swap);
3881 * current_threshold points to threshold just below usage.
3882 * If it's not true, a threshold was crossed after last
3883 * call of __mem_cgroup_threshold().
3885 i = t->current_threshold;
3888 * Iterate backward over array of thresholds starting from
3889 * current_threshold and check if a threshold is crossed.
3890 * If none of thresholds below usage is crossed, we read
3891 * only one element of the array here.
3893 for (; i >= 0 && unlikely(t->entries[i].threshold > usage); i--)
3894 eventfd_signal(t->entries[i].eventfd, 1);
3896 /* i = current_threshold + 1 */
3900 * Iterate forward over array of thresholds starting from
3901 * current_threshold+1 and check if a threshold is crossed.
3902 * If none of thresholds above usage is crossed, we read
3903 * only one element of the array here.
3905 for (; i < t->size && unlikely(t->entries[i].threshold <= usage); i++)
3906 eventfd_signal(t->entries[i].eventfd, 1);
3908 /* Update current_threshold */
3909 t->current_threshold = i - 1;
3914 static void mem_cgroup_threshold(struct mem_cgroup *memcg)
3917 __mem_cgroup_threshold(memcg, false);
3918 if (do_swap_account)
3919 __mem_cgroup_threshold(memcg, true);
3921 memcg = parent_mem_cgroup(memcg);
3925 static int compare_thresholds(const void *a, const void *b)
3927 const struct mem_cgroup_threshold *_a = a;
3928 const struct mem_cgroup_threshold *_b = b;
3930 return _a->threshold - _b->threshold;
3933 static int mem_cgroup_oom_notify_cb(struct mem_cgroup *mem)
3935 struct mem_cgroup_eventfd_list *ev;
3937 list_for_each_entry(ev, &mem->oom_notify, list)
3938 eventfd_signal(ev->eventfd, 1);
3942 static void mem_cgroup_oom_notify(struct mem_cgroup *mem)
3944 struct mem_cgroup *iter;
3946 for_each_mem_cgroup_tree(iter, mem)
3947 mem_cgroup_oom_notify_cb(iter);
3950 static int mem_cgroup_usage_register_event(struct cgroup *cgrp,
3951 struct cftype *cft, struct eventfd_ctx *eventfd, const char *args)
3953 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
3954 struct mem_cgroup_thresholds *thresholds;
3955 struct mem_cgroup_threshold_ary *new;
3956 int type = MEMFILE_TYPE(cft->private);
3957 u64 threshold, usage;
3960 ret = res_counter_memparse_write_strategy(args, &threshold);
3964 mutex_lock(&memcg->thresholds_lock);
3967 thresholds = &memcg->thresholds;
3968 else if (type == _MEMSWAP)
3969 thresholds = &memcg->memsw_thresholds;
3973 usage = mem_cgroup_usage(memcg, type == _MEMSWAP);
3975 /* Check if a threshold crossed before adding a new one */
3976 if (thresholds->primary)
3977 __mem_cgroup_threshold(memcg, type == _MEMSWAP);
3979 size = thresholds->primary ? thresholds->primary->size + 1 : 1;
3981 /* Allocate memory for new array of thresholds */
3982 new = kmalloc(sizeof(*new) + size * sizeof(struct mem_cgroup_threshold),
3990 /* Copy thresholds (if any) to new array */
3991 if (thresholds->primary) {
3992 memcpy(new->entries, thresholds->primary->entries, (size - 1) *
3993 sizeof(struct mem_cgroup_threshold));
3996 /* Add new threshold */
3997 new->entries[size - 1].eventfd = eventfd;
3998 new->entries[size - 1].threshold = threshold;
4000 /* Sort thresholds. Registering of new threshold isn't time-critical */
4001 sort(new->entries, size, sizeof(struct mem_cgroup_threshold),
4002 compare_thresholds, NULL);
4004 /* Find current threshold */
4005 new->current_threshold = -1;
4006 for (i = 0; i < size; i++) {
4007 if (new->entries[i].threshold < usage) {
4009 * new->current_threshold will not be used until
4010 * rcu_assign_pointer(), so it's safe to increment
4013 ++new->current_threshold;
4017 /* Free old spare buffer and save old primary buffer as spare */
4018 kfree(thresholds->spare);
4019 thresholds->spare = thresholds->primary;
4021 rcu_assign_pointer(thresholds->primary, new);
4023 /* To be sure that nobody uses thresholds */
4027 mutex_unlock(&memcg->thresholds_lock);
4032 static void mem_cgroup_usage_unregister_event(struct cgroup *cgrp,
4033 struct cftype *cft, struct eventfd_ctx *eventfd)
4035 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
4036 struct mem_cgroup_thresholds *thresholds;
4037 struct mem_cgroup_threshold_ary *new;
4038 int type = MEMFILE_TYPE(cft->private);
4042 mutex_lock(&memcg->thresholds_lock);
4044 thresholds = &memcg->thresholds;
4045 else if (type == _MEMSWAP)
4046 thresholds = &memcg->memsw_thresholds;
4051 * Something went wrong if we trying to unregister a threshold
4052 * if we don't have thresholds
4054 BUG_ON(!thresholds);
4056 usage = mem_cgroup_usage(memcg, type == _MEMSWAP);
4058 /* Check if a threshold crossed before removing */
4059 __mem_cgroup_threshold(memcg, type == _MEMSWAP);
4061 /* Calculate new number of threshold */
4063 for (i = 0; i < thresholds->primary->size; i++) {
4064 if (thresholds->primary->entries[i].eventfd != eventfd)
4068 new = thresholds->spare;
4070 /* Set thresholds array to NULL if we don't have thresholds */
4079 /* Copy thresholds and find current threshold */
4080 new->current_threshold = -1;
4081 for (i = 0, j = 0; i < thresholds->primary->size; i++) {
4082 if (thresholds->primary->entries[i].eventfd == eventfd)
4085 new->entries[j] = thresholds->primary->entries[i];
4086 if (new->entries[j].threshold < usage) {
4088 * new->current_threshold will not be used
4089 * until rcu_assign_pointer(), so it's safe to increment
4092 ++new->current_threshold;
4098 /* Swap primary and spare array */
4099 thresholds->spare = thresholds->primary;
4100 rcu_assign_pointer(thresholds->primary, new);
4102 /* To be sure that nobody uses thresholds */
4105 mutex_unlock(&memcg->thresholds_lock);
4108 static int mem_cgroup_oom_register_event(struct cgroup *cgrp,
4109 struct cftype *cft, struct eventfd_ctx *eventfd, const char *args)
4111 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
4112 struct mem_cgroup_eventfd_list *event;
4113 int type = MEMFILE_TYPE(cft->private);
4115 BUG_ON(type != _OOM_TYPE);
4116 event = kmalloc(sizeof(*event), GFP_KERNEL);
4120 mutex_lock(&memcg_oom_mutex);
4122 event->eventfd = eventfd;
4123 list_add(&event->list, &memcg->oom_notify);
4125 /* already in OOM ? */
4126 if (atomic_read(&memcg->oom_lock))
4127 eventfd_signal(eventfd, 1);
4128 mutex_unlock(&memcg_oom_mutex);
4133 static void mem_cgroup_oom_unregister_event(struct cgroup *cgrp,
4134 struct cftype *cft, struct eventfd_ctx *eventfd)
4136 struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp);
4137 struct mem_cgroup_eventfd_list *ev, *tmp;
4138 int type = MEMFILE_TYPE(cft->private);
4140 BUG_ON(type != _OOM_TYPE);
4142 mutex_lock(&memcg_oom_mutex);
4144 list_for_each_entry_safe(ev, tmp, &mem->oom_notify, list) {
4145 if (ev->eventfd == eventfd) {
4146 list_del(&ev->list);
4151 mutex_unlock(&memcg_oom_mutex);
4154 static int mem_cgroup_oom_control_read(struct cgroup *cgrp,
4155 struct cftype *cft, struct cgroup_map_cb *cb)
4157 struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp);
4159 cb->fill(cb, "oom_kill_disable", mem->oom_kill_disable);
4161 if (atomic_read(&mem->oom_lock))
4162 cb->fill(cb, "under_oom", 1);
4164 cb->fill(cb, "under_oom", 0);
4168 static int mem_cgroup_oom_control_write(struct cgroup *cgrp,
4169 struct cftype *cft, u64 val)
4171 struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp);
4172 struct mem_cgroup *parent;
4174 /* cannot set to root cgroup and only 0 and 1 are allowed */
4175 if (!cgrp->parent || !((val == 0) || (val == 1)))
4178 parent = mem_cgroup_from_cont(cgrp->parent);
4181 /* oom-kill-disable is a flag for subhierarchy. */
4182 if ((parent->use_hierarchy) ||
4183 (mem->use_hierarchy && !list_empty(&cgrp->children))) {
4187 mem->oom_kill_disable = val;
4189 memcg_oom_recover(mem);
4194 static struct cftype mem_cgroup_files[] = {
4196 .name = "usage_in_bytes",
4197 .private = MEMFILE_PRIVATE(_MEM, RES_USAGE),
4198 .read_u64 = mem_cgroup_read,
4199 .register_event = mem_cgroup_usage_register_event,
4200 .unregister_event = mem_cgroup_usage_unregister_event,
4203 .name = "max_usage_in_bytes",
4204 .private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE),
4205 .trigger = mem_cgroup_reset,
4206 .read_u64 = mem_cgroup_read,
4209 .name = "limit_in_bytes",
4210 .private = MEMFILE_PRIVATE(_MEM, RES_LIMIT),
4211 .write_string = mem_cgroup_write,
4212 .read_u64 = mem_cgroup_read,
4215 .name = "soft_limit_in_bytes",
4216 .private = MEMFILE_PRIVATE(_MEM, RES_SOFT_LIMIT),
4217 .write_string = mem_cgroup_write,
4218 .read_u64 = mem_cgroup_read,
4222 .private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT),
4223 .trigger = mem_cgroup_reset,
4224 .read_u64 = mem_cgroup_read,
4228 .read_map = mem_control_stat_show,
4231 .name = "force_empty",
4232 .trigger = mem_cgroup_force_empty_write,
4235 .name = "use_hierarchy",
4236 .write_u64 = mem_cgroup_hierarchy_write,
4237 .read_u64 = mem_cgroup_hierarchy_read,
4240 .name = "swappiness",
4241 .read_u64 = mem_cgroup_swappiness_read,
4242 .write_u64 = mem_cgroup_swappiness_write,
4245 .name = "move_charge_at_immigrate",
4246 .read_u64 = mem_cgroup_move_charge_read,
4247 .write_u64 = mem_cgroup_move_charge_write,
4250 .name = "oom_control",
4251 .read_map = mem_cgroup_oom_control_read,
4252 .write_u64 = mem_cgroup_oom_control_write,
4253 .register_event = mem_cgroup_oom_register_event,
4254 .unregister_event = mem_cgroup_oom_unregister_event,
4255 .private = MEMFILE_PRIVATE(_OOM_TYPE, OOM_CONTROL),
4259 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
4260 static struct cftype memsw_cgroup_files[] = {
4262 .name = "memsw.usage_in_bytes",
4263 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE),
4264 .read_u64 = mem_cgroup_read,
4265 .register_event = mem_cgroup_usage_register_event,
4266 .unregister_event = mem_cgroup_usage_unregister_event,
4269 .name = "memsw.max_usage_in_bytes",
4270 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE),
4271 .trigger = mem_cgroup_reset,
4272 .read_u64 = mem_cgroup_read,
4275 .name = "memsw.limit_in_bytes",
4276 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT),
4277 .write_string = mem_cgroup_write,
4278 .read_u64 = mem_cgroup_read,
4281 .name = "memsw.failcnt",
4282 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT),
4283 .trigger = mem_cgroup_reset,
4284 .read_u64 = mem_cgroup_read,
4288 static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss)
4290 if (!do_swap_account)
4292 return cgroup_add_files(cont, ss, memsw_cgroup_files,
4293 ARRAY_SIZE(memsw_cgroup_files));
4296 static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss)
4302 static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
4304 struct mem_cgroup_per_node *pn;
4305 struct mem_cgroup_per_zone *mz;
4307 int zone, tmp = node;
4309 * This routine is called against possible nodes.
4310 * But it's BUG to call kmalloc() against offline node.
4312 * TODO: this routine can waste much memory for nodes which will
4313 * never be onlined. It's better to use memory hotplug callback
4316 if (!node_state(node, N_NORMAL_MEMORY))
4318 pn = kzalloc_node(sizeof(*pn), GFP_KERNEL, tmp);
4322 mem->info.nodeinfo[node] = pn;
4323 for (zone = 0; zone < MAX_NR_ZONES; zone++) {
4324 mz = &pn->zoneinfo[zone];
4326 INIT_LIST_HEAD(&mz->lists[l]);
4327 mz->usage_in_excess = 0;
4328 mz->on_tree = false;
4334 static void free_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
4336 kfree(mem->info.nodeinfo[node]);
4339 static struct mem_cgroup *mem_cgroup_alloc(void)
4341 struct mem_cgroup *mem;
4342 int size = sizeof(struct mem_cgroup);
4344 /* Can be very big if MAX_NUMNODES is very big */
4345 if (size < PAGE_SIZE)
4346 mem = kzalloc(size, GFP_KERNEL);
4348 mem = vzalloc(size);
4353 mem->stat = alloc_percpu(struct mem_cgroup_stat_cpu);
4356 spin_lock_init(&mem->pcp_counter_lock);
4360 if (size < PAGE_SIZE)
4368 * At destroying mem_cgroup, references from swap_cgroup can remain.
4369 * (scanning all at force_empty is too costly...)
4371 * Instead of clearing all references at force_empty, we remember
4372 * the number of reference from swap_cgroup and free mem_cgroup when
4373 * it goes down to 0.
4375 * Removal of cgroup itself succeeds regardless of refs from swap.
4378 static void __mem_cgroup_free(struct mem_cgroup *mem)
4382 mem_cgroup_remove_from_trees(mem);
4383 free_css_id(&mem_cgroup_subsys, &mem->css);
4385 for_each_node_state(node, N_POSSIBLE)
4386 free_mem_cgroup_per_zone_info(mem, node);
4388 free_percpu(mem->stat);
4389 if (sizeof(struct mem_cgroup) < PAGE_SIZE)
4395 static void mem_cgroup_get(struct mem_cgroup *mem)
4397 atomic_inc(&mem->refcnt);
4400 static void __mem_cgroup_put(struct mem_cgroup *mem, int count)
4402 if (atomic_sub_and_test(count, &mem->refcnt)) {
4403 struct mem_cgroup *parent = parent_mem_cgroup(mem);
4404 __mem_cgroup_free(mem);
4406 mem_cgroup_put(parent);
4410 static void mem_cgroup_put(struct mem_cgroup *mem)
4412 __mem_cgroup_put(mem, 1);
4416 * Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled.
4418 static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem)
4420 if (!mem->res.parent)
4422 return mem_cgroup_from_res_counter(mem->res.parent, res);
4425 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
4426 static void __init enable_swap_cgroup(void)
4428 if (!mem_cgroup_disabled() && really_do_swap_account)
4429 do_swap_account = 1;
4432 static void __init enable_swap_cgroup(void)
4437 static int mem_cgroup_soft_limit_tree_init(void)
4439 struct mem_cgroup_tree_per_node *rtpn;
4440 struct mem_cgroup_tree_per_zone *rtpz;
4441 int tmp, node, zone;
4443 for_each_node_state(node, N_POSSIBLE) {
4445 if (!node_state(node, N_NORMAL_MEMORY))
4447 rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL, tmp);
4451 soft_limit_tree.rb_tree_per_node[node] = rtpn;
4453 for (zone = 0; zone < MAX_NR_ZONES; zone++) {
4454 rtpz = &rtpn->rb_tree_per_zone[zone];
4455 rtpz->rb_root = RB_ROOT;
4456 spin_lock_init(&rtpz->lock);
4462 static struct cgroup_subsys_state * __ref
4463 mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
4465 struct mem_cgroup *mem, *parent;
4466 long error = -ENOMEM;
4469 mem = mem_cgroup_alloc();
4471 return ERR_PTR(error);
4473 for_each_node_state(node, N_POSSIBLE)
4474 if (alloc_mem_cgroup_per_zone_info(mem, node))
4478 if (cont->parent == NULL) {
4480 enable_swap_cgroup();
4482 root_mem_cgroup = mem;
4483 if (mem_cgroup_soft_limit_tree_init())
4485 for_each_possible_cpu(cpu) {
4486 struct memcg_stock_pcp *stock =
4487 &per_cpu(memcg_stock, cpu);
4488 INIT_WORK(&stock->work, drain_local_stock);
4490 hotcpu_notifier(memcg_cpu_hotplug_callback, 0);
4492 parent = mem_cgroup_from_cont(cont->parent);
4493 mem->use_hierarchy = parent->use_hierarchy;
4494 mem->oom_kill_disable = parent->oom_kill_disable;
4497 if (parent && parent->use_hierarchy) {
4498 res_counter_init(&mem->res, &parent->res);
4499 res_counter_init(&mem->memsw, &parent->memsw);
4501 * We increment refcnt of the parent to ensure that we can
4502 * safely access it on res_counter_charge/uncharge.
4503 * This refcnt will be decremented when freeing this
4504 * mem_cgroup(see mem_cgroup_put).
4506 mem_cgroup_get(parent);
4508 res_counter_init(&mem->res, NULL);
4509 res_counter_init(&mem->memsw, NULL);
4511 mem->last_scanned_child = 0;
4512 INIT_LIST_HEAD(&mem->oom_notify);
4515 mem->swappiness = get_swappiness(parent);
4516 atomic_set(&mem->refcnt, 1);
4517 mem->move_charge_at_immigrate = 0;
4518 mutex_init(&mem->thresholds_lock);
4521 __mem_cgroup_free(mem);
4522 root_mem_cgroup = NULL;
4523 return ERR_PTR(error);
4526 static int mem_cgroup_pre_destroy(struct cgroup_subsys *ss,
4527 struct cgroup *cont)
4529 struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
4531 return mem_cgroup_force_empty(mem, false);
4534 static void mem_cgroup_destroy(struct cgroup_subsys *ss,
4535 struct cgroup *cont)
4537 struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
4539 mem_cgroup_put(mem);
4542 static int mem_cgroup_populate(struct cgroup_subsys *ss,
4543 struct cgroup *cont)
4547 ret = cgroup_add_files(cont, ss, mem_cgroup_files,
4548 ARRAY_SIZE(mem_cgroup_files));
4551 ret = register_memsw_files(cont, ss);
4556 /* Handlers for move charge at task migration. */
4557 #define PRECHARGE_COUNT_AT_ONCE 256
4558 static int mem_cgroup_do_precharge(unsigned long count)
4561 int batch_count = PRECHARGE_COUNT_AT_ONCE;
4562 struct mem_cgroup *mem = mc.to;
4564 if (mem_cgroup_is_root(mem)) {
4565 mc.precharge += count;
4566 /* we don't need css_get for root */
4569 /* try to charge at once */
4571 struct res_counter *dummy;
4573 * "mem" cannot be under rmdir() because we've already checked
4574 * by cgroup_lock_live_cgroup() that it is not removed and we
4575 * are still under the same cgroup_mutex. So we can postpone
4578 if (res_counter_charge(&mem->res, PAGE_SIZE * count, &dummy))
4580 if (do_swap_account && res_counter_charge(&mem->memsw,
4581 PAGE_SIZE * count, &dummy)) {
4582 res_counter_uncharge(&mem->res, PAGE_SIZE * count);
4585 mc.precharge += count;
4589 /* fall back to one by one charge */
4591 if (signal_pending(current)) {
4595 if (!batch_count--) {
4596 batch_count = PRECHARGE_COUNT_AT_ONCE;
4599 ret = __mem_cgroup_try_charge(NULL, GFP_KERNEL, &mem, false,
4602 /* mem_cgroup_clear_mc() will do uncharge later */
4610 * is_target_pte_for_mc - check a pte whether it is valid for move charge
4611 * @vma: the vma the pte to be checked belongs
4612 * @addr: the address corresponding to the pte to be checked
4613 * @ptent: the pte to be checked
4614 * @target: the pointer the target page or swap ent will be stored(can be NULL)
4617 * 0(MC_TARGET_NONE): if the pte is not a target for move charge.
4618 * 1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for
4619 * move charge. if @target is not NULL, the page is stored in target->page
4620 * with extra refcnt got(Callers should handle it).
4621 * 2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a
4622 * target for charge migration. if @target is not NULL, the entry is stored
4625 * Called with pte lock held.
4632 enum mc_target_type {
4633 MC_TARGET_NONE, /* not used */
4638 static struct page *mc_handle_present_pte(struct vm_area_struct *vma,
4639 unsigned long addr, pte_t ptent)
4641 struct page *page = vm_normal_page(vma, addr, ptent);
4643 if (!page || !page_mapped(page))
4645 if (PageAnon(page)) {
4646 /* we don't move shared anon */
4647 if (!move_anon() || page_mapcount(page) > 2)
4649 } else if (!move_file())
4650 /* we ignore mapcount for file pages */
4652 if (!get_page_unless_zero(page))
4658 static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
4659 unsigned long addr, pte_t ptent, swp_entry_t *entry)
4662 struct page *page = NULL;
4663 swp_entry_t ent = pte_to_swp_entry(ptent);
4665 if (!move_anon() || non_swap_entry(ent))
4667 usage_count = mem_cgroup_count_swap_user(ent, &page);
4668 if (usage_count > 1) { /* we don't move shared anon */
4673 if (do_swap_account)
4674 entry->val = ent.val;
4679 static struct page *mc_handle_file_pte(struct vm_area_struct *vma,
4680 unsigned long addr, pte_t ptent, swp_entry_t *entry)
4682 struct page *page = NULL;
4683 struct inode *inode;
4684 struct address_space *mapping;
4687 if (!vma->vm_file) /* anonymous vma */
4692 inode = vma->vm_file->f_path.dentry->d_inode;
4693 mapping = vma->vm_file->f_mapping;
4694 if (pte_none(ptent))
4695 pgoff = linear_page_index(vma, addr);
4696 else /* pte_file(ptent) is true */
4697 pgoff = pte_to_pgoff(ptent);
4699 /* page is moved even if it's not RSS of this task(page-faulted). */
4700 if (!mapping_cap_swap_backed(mapping)) { /* normal file */
4701 page = find_get_page(mapping, pgoff);
4702 } else { /* shmem/tmpfs file. we should take account of swap too. */
4704 mem_cgroup_get_shmem_target(inode, pgoff, &page, &ent);
4705 if (do_swap_account)
4706 entry->val = ent.val;
4712 static int is_target_pte_for_mc(struct vm_area_struct *vma,
4713 unsigned long addr, pte_t ptent, union mc_target *target)
4715 struct page *page = NULL;
4716 struct page_cgroup *pc;
4718 swp_entry_t ent = { .val = 0 };
4720 if (pte_present(ptent))
4721 page = mc_handle_present_pte(vma, addr, ptent);
4722 else if (is_swap_pte(ptent))
4723 page = mc_handle_swap_pte(vma, addr, ptent, &ent);
4724 else if (pte_none(ptent) || pte_file(ptent))
4725 page = mc_handle_file_pte(vma, addr, ptent, &ent);
4727 if (!page && !ent.val)
4730 pc = lookup_page_cgroup(page);
4732 * Do only loose check w/o page_cgroup lock.
4733 * mem_cgroup_move_account() checks the pc is valid or not under
4736 if (PageCgroupUsed(pc) && pc->mem_cgroup == mc.from) {
4737 ret = MC_TARGET_PAGE;
4739 target->page = page;
4741 if (!ret || !target)
4744 /* There is a swap entry and a page doesn't exist or isn't charged */
4745 if (ent.val && !ret &&
4746 css_id(&mc.from->css) == lookup_swap_cgroup(ent)) {
4747 ret = MC_TARGET_SWAP;
4754 static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd,
4755 unsigned long addr, unsigned long end,
4756 struct mm_walk *walk)
4758 struct vm_area_struct *vma = walk->private;
4762 split_huge_page_pmd(walk->mm, pmd);
4764 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
4765 for (; addr != end; pte++, addr += PAGE_SIZE)
4766 if (is_target_pte_for_mc(vma, addr, *pte, NULL))
4767 mc.precharge++; /* increment precharge temporarily */
4768 pte_unmap_unlock(pte - 1, ptl);
4774 static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm)
4776 unsigned long precharge;
4777 struct vm_area_struct *vma;
4779 down_read(&mm->mmap_sem);
4780 for (vma = mm->mmap; vma; vma = vma->vm_next) {
4781 struct mm_walk mem_cgroup_count_precharge_walk = {
4782 .pmd_entry = mem_cgroup_count_precharge_pte_range,
4786 if (is_vm_hugetlb_page(vma))
4788 walk_page_range(vma->vm_start, vma->vm_end,
4789 &mem_cgroup_count_precharge_walk);
4791 up_read(&mm->mmap_sem);
4793 precharge = mc.precharge;
4799 static int mem_cgroup_precharge_mc(struct mm_struct *mm)
4801 unsigned long precharge = mem_cgroup_count_precharge(mm);
4803 VM_BUG_ON(mc.moving_task);
4804 mc.moving_task = current;
4805 return mem_cgroup_do_precharge(precharge);
4808 /* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */
4809 static void __mem_cgroup_clear_mc(void)
4811 struct mem_cgroup *from = mc.from;
4812 struct mem_cgroup *to = mc.to;
4814 /* we must uncharge all the leftover precharges from mc.to */
4816 __mem_cgroup_cancel_charge(mc.to, mc.precharge);
4820 * we didn't uncharge from mc.from at mem_cgroup_move_account(), so
4821 * we must uncharge here.
4823 if (mc.moved_charge) {
4824 __mem_cgroup_cancel_charge(mc.from, mc.moved_charge);
4825 mc.moved_charge = 0;
4827 /* we must fixup refcnts and charges */
4828 if (mc.moved_swap) {
4829 /* uncharge swap account from the old cgroup */
4830 if (!mem_cgroup_is_root(mc.from))
4831 res_counter_uncharge(&mc.from->memsw,
4832 PAGE_SIZE * mc.moved_swap);
4833 __mem_cgroup_put(mc.from, mc.moved_swap);
4835 if (!mem_cgroup_is_root(mc.to)) {
4837 * we charged both to->res and to->memsw, so we should
4840 res_counter_uncharge(&mc.to->res,
4841 PAGE_SIZE * mc.moved_swap);
4843 /* we've already done mem_cgroup_get(mc.to) */
4846 memcg_oom_recover(from);
4847 memcg_oom_recover(to);
4848 wake_up_all(&mc.waitq);
4851 static void mem_cgroup_clear_mc(void)
4853 struct mem_cgroup *from = mc.from;
4856 * we must clear moving_task before waking up waiters at the end of
4859 mc.moving_task = NULL;
4860 __mem_cgroup_clear_mc();
4861 spin_lock(&mc.lock);
4864 spin_unlock(&mc.lock);
4865 mem_cgroup_end_move(from);
4868 static int mem_cgroup_can_attach(struct cgroup_subsys *ss,
4869 struct cgroup *cgroup,
4870 struct task_struct *p,
4874 struct mem_cgroup *mem = mem_cgroup_from_cont(cgroup);
4876 if (mem->move_charge_at_immigrate) {
4877 struct mm_struct *mm;
4878 struct mem_cgroup *from = mem_cgroup_from_task(p);
4880 VM_BUG_ON(from == mem);
4882 mm = get_task_mm(p);
4885 /* We move charges only when we move a owner of the mm */
4886 if (mm->owner == p) {
4889 VM_BUG_ON(mc.precharge);
4890 VM_BUG_ON(mc.moved_charge);
4891 VM_BUG_ON(mc.moved_swap);
4892 mem_cgroup_start_move(from);
4893 spin_lock(&mc.lock);
4896 spin_unlock(&mc.lock);
4897 /* We set mc.moving_task later */
4899 ret = mem_cgroup_precharge_mc(mm);
4901 mem_cgroup_clear_mc();
4908 static void mem_cgroup_cancel_attach(struct cgroup_subsys *ss,
4909 struct cgroup *cgroup,
4910 struct task_struct *p,
4913 mem_cgroup_clear_mc();
4916 static int mem_cgroup_move_charge_pte_range(pmd_t *pmd,
4917 unsigned long addr, unsigned long end,
4918 struct mm_walk *walk)
4921 struct vm_area_struct *vma = walk->private;
4925 split_huge_page_pmd(walk->mm, pmd);
4927 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
4928 for (; addr != end; addr += PAGE_SIZE) {
4929 pte_t ptent = *(pte++);
4930 union mc_target target;
4933 struct page_cgroup *pc;
4939 type = is_target_pte_for_mc(vma, addr, ptent, &target);
4941 case MC_TARGET_PAGE:
4943 if (isolate_lru_page(page))
4945 pc = lookup_page_cgroup(page);
4946 if (!mem_cgroup_move_account(page, pc,
4947 mc.from, mc.to, false, PAGE_SIZE)) {
4949 /* we uncharge from mc.from later. */
4952 putback_lru_page(page);
4953 put: /* is_target_pte_for_mc() gets the page */
4956 case MC_TARGET_SWAP:
4958 if (!mem_cgroup_move_swap_account(ent,
4959 mc.from, mc.to, false)) {
4961 /* we fixup refcnts and charges later. */
4969 pte_unmap_unlock(pte - 1, ptl);
4974 * We have consumed all precharges we got in can_attach().
4975 * We try charge one by one, but don't do any additional
4976 * charges to mc.to if we have failed in charge once in attach()
4979 ret = mem_cgroup_do_precharge(1);
4987 static void mem_cgroup_move_charge(struct mm_struct *mm)
4989 struct vm_area_struct *vma;
4991 lru_add_drain_all();
4993 if (unlikely(!down_read_trylock(&mm->mmap_sem))) {
4995 * Someone who are holding the mmap_sem might be waiting in
4996 * waitq. So we cancel all extra charges, wake up all waiters,
4997 * and retry. Because we cancel precharges, we might not be able
4998 * to move enough charges, but moving charge is a best-effort
4999 * feature anyway, so it wouldn't be a big problem.
5001 __mem_cgroup_clear_mc();
5005 for (vma = mm->mmap; vma; vma = vma->vm_next) {
5007 struct mm_walk mem_cgroup_move_charge_walk = {
5008 .pmd_entry = mem_cgroup_move_charge_pte_range,
5012 if (is_vm_hugetlb_page(vma))
5014 ret = walk_page_range(vma->vm_start, vma->vm_end,
5015 &mem_cgroup_move_charge_walk);
5018 * means we have consumed all precharges and failed in
5019 * doing additional charge. Just abandon here.
5023 up_read(&mm->mmap_sem);
5026 static void mem_cgroup_move_task(struct cgroup_subsys *ss,
5027 struct cgroup *cont,
5028 struct cgroup *old_cont,
5029 struct task_struct *p,
5032 struct mm_struct *mm;
5035 /* no need to move charge */
5038 mm = get_task_mm(p);
5040 mem_cgroup_move_charge(mm);
5043 mem_cgroup_clear_mc();
5045 #else /* !CONFIG_MMU */
5046 static int mem_cgroup_can_attach(struct cgroup_subsys *ss,
5047 struct cgroup *cgroup,
5048 struct task_struct *p,
5053 static void mem_cgroup_cancel_attach(struct cgroup_subsys *ss,
5054 struct cgroup *cgroup,
5055 struct task_struct *p,
5059 static void mem_cgroup_move_task(struct cgroup_subsys *ss,
5060 struct cgroup *cont,
5061 struct cgroup *old_cont,
5062 struct task_struct *p,
5068 struct cgroup_subsys mem_cgroup_subsys = {
5070 .subsys_id = mem_cgroup_subsys_id,
5071 .create = mem_cgroup_create,
5072 .pre_destroy = mem_cgroup_pre_destroy,
5073 .destroy = mem_cgroup_destroy,
5074 .populate = mem_cgroup_populate,
5075 .can_attach = mem_cgroup_can_attach,
5076 .cancel_attach = mem_cgroup_cancel_attach,
5077 .attach = mem_cgroup_move_task,
5082 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
5083 static int __init enable_swap_account(char *s)
5085 /* consider enabled if no parameter or 1 is given */
5086 if (!(*s) || !strcmp(s, "=1"))
5087 really_do_swap_account = 1;
5088 else if (!strcmp(s, "=0"))
5089 really_do_swap_account = 0;
5092 __setup("swapaccount", enable_swap_account);
5094 static int __init disable_swap_account(char *s)
5096 printk_once("noswapaccount is deprecated and will be removed in 2.6.40. Use swapaccount=0 instead\n");
5097 enable_swap_account("=0");
5100 __setup("noswapaccount", disable_swap_account);