1 /* memcontrol.c - Memory Controller
3 * Copyright IBM Corporation, 2007
4 * Author Balbir Singh <balbir@linux.vnet.ibm.com>
6 * Copyright 2007 OpenVZ SWsoft Inc
7 * Author: Pavel Emelianov <xemul@openvz.org>
10 * Copyright (C) 2009 Nokia Corporation
11 * Author: Kirill A. Shutemov
13 * This program is free software; you can redistribute it and/or modify
14 * it under the terms of the GNU General Public License as published by
15 * the Free Software Foundation; either version 2 of the License, or
16 * (at your option) any later version.
18 * This program is distributed in the hope that it will be useful,
19 * but WITHOUT ANY WARRANTY; without even the implied warranty of
20 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
21 * GNU General Public License for more details.
24 #include <linux/res_counter.h>
25 #include <linux/memcontrol.h>
26 #include <linux/cgroup.h>
28 #include <linux/hugetlb.h>
29 #include <linux/pagemap.h>
30 #include <linux/smp.h>
31 #include <linux/page-flags.h>
32 #include <linux/backing-dev.h>
33 #include <linux/bit_spinlock.h>
34 #include <linux/rcupdate.h>
35 #include <linux/limits.h>
36 #include <linux/mutex.h>
37 #include <linux/rbtree.h>
38 #include <linux/slab.h>
39 #include <linux/swap.h>
40 #include <linux/swapops.h>
41 #include <linux/spinlock.h>
42 #include <linux/eventfd.h>
43 #include <linux/sort.h>
45 #include <linux/seq_file.h>
46 #include <linux/vmalloc.h>
47 #include <linux/mm_inline.h>
48 #include <linux/page_cgroup.h>
49 #include <linux/cpu.h>
50 #include <linux/oom.h>
53 #include <asm/uaccess.h>
55 #include <trace/events/vmscan.h>
57 struct cgroup_subsys mem_cgroup_subsys __read_mostly;
58 #define MEM_CGROUP_RECLAIM_RETRIES 5
59 struct mem_cgroup *root_mem_cgroup __read_mostly;
61 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
62 /* Turned on only when memory cgroup is enabled && really_do_swap_account = 1 */
63 int do_swap_account __read_mostly;
65 /* for remember boot option*/
66 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP_ENABLED
67 static int really_do_swap_account __initdata = 1;
69 static int really_do_swap_account __initdata = 0;
73 #define do_swap_account (0)
77 * Per memcg event counter is incremented at every pagein/pageout. This counter
78 * is used for trigger some periodic events. This is straightforward and better
79 * than using jiffies etc. to handle periodic memcg event.
81 * These values will be used as !((event) & ((1 <<(thresh)) - 1))
83 #define THRESHOLDS_EVENTS_THRESH (7) /* once in 128 */
84 #define SOFTLIMIT_EVENTS_THRESH (10) /* once in 1024 */
87 * Statistics for memory cgroup.
89 enum mem_cgroup_stat_index {
91 * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss.
93 MEM_CGROUP_STAT_CACHE, /* # of pages charged as cache */
94 MEM_CGROUP_STAT_RSS, /* # of pages charged as anon rss */
95 MEM_CGROUP_STAT_FILE_MAPPED, /* # of pages charged as file rss */
96 MEM_CGROUP_STAT_PGPGIN_COUNT, /* # of pages paged in */
97 MEM_CGROUP_STAT_PGPGOUT_COUNT, /* # of pages paged out */
98 MEM_CGROUP_STAT_SWAPOUT, /* # of pages, swapped out */
99 MEM_CGROUP_STAT_DATA, /* end of data requires synchronization */
100 /* incremented at every pagein/pageout */
101 MEM_CGROUP_EVENTS = MEM_CGROUP_STAT_DATA,
102 MEM_CGROUP_ON_MOVE, /* someone is moving account between groups */
104 MEM_CGROUP_STAT_NSTATS,
107 struct mem_cgroup_stat_cpu {
108 s64 count[MEM_CGROUP_STAT_NSTATS];
112 * per-zone information in memory controller.
114 struct mem_cgroup_per_zone {
116 * spin_lock to protect the per cgroup LRU
118 struct list_head lists[NR_LRU_LISTS];
119 unsigned long count[NR_LRU_LISTS];
121 struct zone_reclaim_stat reclaim_stat;
122 struct rb_node tree_node; /* RB tree node */
123 unsigned long long usage_in_excess;/* Set to the value by which */
124 /* the soft limit is exceeded*/
126 struct mem_cgroup *mem; /* Back pointer, we cannot */
127 /* use container_of */
129 /* Macro for accessing counter */
130 #define MEM_CGROUP_ZSTAT(mz, idx) ((mz)->count[(idx)])
132 struct mem_cgroup_per_node {
133 struct mem_cgroup_per_zone zoneinfo[MAX_NR_ZONES];
136 struct mem_cgroup_lru_info {
137 struct mem_cgroup_per_node *nodeinfo[MAX_NUMNODES];
141 * Cgroups above their limits are maintained in a RB-Tree, independent of
142 * their hierarchy representation
145 struct mem_cgroup_tree_per_zone {
146 struct rb_root rb_root;
150 struct mem_cgroup_tree_per_node {
151 struct mem_cgroup_tree_per_zone rb_tree_per_zone[MAX_NR_ZONES];
154 struct mem_cgroup_tree {
155 struct mem_cgroup_tree_per_node *rb_tree_per_node[MAX_NUMNODES];
158 static struct mem_cgroup_tree soft_limit_tree __read_mostly;
160 struct mem_cgroup_threshold {
161 struct eventfd_ctx *eventfd;
166 struct mem_cgroup_threshold_ary {
167 /* An array index points to threshold just below usage. */
168 int current_threshold;
169 /* Size of entries[] */
171 /* Array of thresholds */
172 struct mem_cgroup_threshold entries[0];
175 struct mem_cgroup_thresholds {
176 /* Primary thresholds array */
177 struct mem_cgroup_threshold_ary *primary;
179 * Spare threshold array.
180 * This is needed to make mem_cgroup_unregister_event() "never fail".
181 * It must be able to store at least primary->size - 1 entries.
183 struct mem_cgroup_threshold_ary *spare;
187 struct mem_cgroup_eventfd_list {
188 struct list_head list;
189 struct eventfd_ctx *eventfd;
192 static void mem_cgroup_threshold(struct mem_cgroup *mem);
193 static void mem_cgroup_oom_notify(struct mem_cgroup *mem);
196 * The memory controller data structure. The memory controller controls both
197 * page cache and RSS per cgroup. We would eventually like to provide
198 * statistics based on the statistics developed by Rik Van Riel for clock-pro,
199 * to help the administrator determine what knobs to tune.
201 * TODO: Add a water mark for the memory controller. Reclaim will begin when
202 * we hit the water mark. May be even add a low water mark, such that
203 * no reclaim occurs from a cgroup at it's low water mark, this is
204 * a feature that will be implemented much later in the future.
207 struct cgroup_subsys_state css;
209 * the counter to account for memory usage
211 struct res_counter res;
213 * the counter to account for mem+swap usage.
215 struct res_counter memsw;
217 * Per cgroup active and inactive list, similar to the
218 * per zone LRU lists.
220 struct mem_cgroup_lru_info info;
223 protect against reclaim related member.
225 spinlock_t reclaim_param_lock;
228 * While reclaiming in a hierarchy, we cache the last child we
231 int last_scanned_child;
233 * Should the accounting and control be hierarchical, per subtree?
239 unsigned int swappiness;
240 /* OOM-Killer disable */
241 int oom_kill_disable;
243 /* set when res.limit == memsw.limit */
244 bool memsw_is_minimum;
246 /* protect arrays of thresholds */
247 struct mutex thresholds_lock;
249 /* thresholds for memory usage. RCU-protected */
250 struct mem_cgroup_thresholds thresholds;
252 /* thresholds for mem+swap usage. RCU-protected */
253 struct mem_cgroup_thresholds memsw_thresholds;
255 /* For oom notifier event fd */
256 struct list_head oom_notify;
259 * Should we move charges of a task when a task is moved into this
260 * mem_cgroup ? And what type of charges should we move ?
262 unsigned long move_charge_at_immigrate;
266 struct mem_cgroup_stat_cpu *stat;
268 * used when a cpu is offlined or other synchronizations
269 * See mem_cgroup_read_stat().
271 struct mem_cgroup_stat_cpu nocpu_base;
272 spinlock_t pcp_counter_lock;
275 /* Stuffs for move charges at task migration. */
277 * Types of charges to be moved. "move_charge_at_immitgrate" is treated as a
278 * left-shifted bitmap of these types.
281 MOVE_CHARGE_TYPE_ANON, /* private anonymous page and swap of it */
282 MOVE_CHARGE_TYPE_FILE, /* file page(including tmpfs) and swap of it */
286 /* "mc" and its members are protected by cgroup_mutex */
287 static struct move_charge_struct {
288 spinlock_t lock; /* for from, to */
289 struct mem_cgroup *from;
290 struct mem_cgroup *to;
291 unsigned long precharge;
292 unsigned long moved_charge;
293 unsigned long moved_swap;
294 struct task_struct *moving_task; /* a task moving charges */
295 wait_queue_head_t waitq; /* a waitq for other context */
297 .lock = __SPIN_LOCK_UNLOCKED(mc.lock),
298 .waitq = __WAIT_QUEUE_HEAD_INITIALIZER(mc.waitq),
301 static bool move_anon(void)
303 return test_bit(MOVE_CHARGE_TYPE_ANON,
304 &mc.to->move_charge_at_immigrate);
307 static bool move_file(void)
309 return test_bit(MOVE_CHARGE_TYPE_FILE,
310 &mc.to->move_charge_at_immigrate);
314 * Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft
315 * limit reclaim to prevent infinite loops, if they ever occur.
317 #define MEM_CGROUP_MAX_RECLAIM_LOOPS (100)
318 #define MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS (2)
321 MEM_CGROUP_CHARGE_TYPE_CACHE = 0,
322 MEM_CGROUP_CHARGE_TYPE_MAPPED,
323 MEM_CGROUP_CHARGE_TYPE_SHMEM, /* used by page migration of shmem */
324 MEM_CGROUP_CHARGE_TYPE_FORCE, /* used by force_empty */
325 MEM_CGROUP_CHARGE_TYPE_SWAPOUT, /* for accounting swapcache */
326 MEM_CGROUP_CHARGE_TYPE_DROP, /* a page was unused swap cache */
330 /* for encoding cft->private value on file */
333 #define _OOM_TYPE (2)
334 #define MEMFILE_PRIVATE(x, val) (((x) << 16) | (val))
335 #define MEMFILE_TYPE(val) (((val) >> 16) & 0xffff)
336 #define MEMFILE_ATTR(val) ((val) & 0xffff)
337 /* Used for OOM nofiier */
338 #define OOM_CONTROL (0)
341 * Reclaim flags for mem_cgroup_hierarchical_reclaim
343 #define MEM_CGROUP_RECLAIM_NOSWAP_BIT 0x0
344 #define MEM_CGROUP_RECLAIM_NOSWAP (1 << MEM_CGROUP_RECLAIM_NOSWAP_BIT)
345 #define MEM_CGROUP_RECLAIM_SHRINK_BIT 0x1
346 #define MEM_CGROUP_RECLAIM_SHRINK (1 << MEM_CGROUP_RECLAIM_SHRINK_BIT)
347 #define MEM_CGROUP_RECLAIM_SOFT_BIT 0x2
348 #define MEM_CGROUP_RECLAIM_SOFT (1 << MEM_CGROUP_RECLAIM_SOFT_BIT)
350 static void mem_cgroup_get(struct mem_cgroup *mem);
351 static void mem_cgroup_put(struct mem_cgroup *mem);
352 static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem);
353 static void drain_all_stock_async(void);
355 static struct mem_cgroup_per_zone *
356 mem_cgroup_zoneinfo(struct mem_cgroup *mem, int nid, int zid)
358 return &mem->info.nodeinfo[nid]->zoneinfo[zid];
361 struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *mem)
366 static struct mem_cgroup_per_zone *
367 page_cgroup_zoneinfo(struct mem_cgroup *mem, struct page *page)
369 int nid = page_to_nid(page);
370 int zid = page_zonenum(page);
372 return mem_cgroup_zoneinfo(mem, nid, zid);
375 static struct mem_cgroup_tree_per_zone *
376 soft_limit_tree_node_zone(int nid, int zid)
378 return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid];
381 static struct mem_cgroup_tree_per_zone *
382 soft_limit_tree_from_page(struct page *page)
384 int nid = page_to_nid(page);
385 int zid = page_zonenum(page);
387 return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid];
391 __mem_cgroup_insert_exceeded(struct mem_cgroup *mem,
392 struct mem_cgroup_per_zone *mz,
393 struct mem_cgroup_tree_per_zone *mctz,
394 unsigned long long new_usage_in_excess)
396 struct rb_node **p = &mctz->rb_root.rb_node;
397 struct rb_node *parent = NULL;
398 struct mem_cgroup_per_zone *mz_node;
403 mz->usage_in_excess = new_usage_in_excess;
404 if (!mz->usage_in_excess)
408 mz_node = rb_entry(parent, struct mem_cgroup_per_zone,
410 if (mz->usage_in_excess < mz_node->usage_in_excess)
413 * We can't avoid mem cgroups that are over their soft
414 * limit by the same amount
416 else if (mz->usage_in_excess >= mz_node->usage_in_excess)
419 rb_link_node(&mz->tree_node, parent, p);
420 rb_insert_color(&mz->tree_node, &mctz->rb_root);
425 __mem_cgroup_remove_exceeded(struct mem_cgroup *mem,
426 struct mem_cgroup_per_zone *mz,
427 struct mem_cgroup_tree_per_zone *mctz)
431 rb_erase(&mz->tree_node, &mctz->rb_root);
436 mem_cgroup_remove_exceeded(struct mem_cgroup *mem,
437 struct mem_cgroup_per_zone *mz,
438 struct mem_cgroup_tree_per_zone *mctz)
440 spin_lock(&mctz->lock);
441 __mem_cgroup_remove_exceeded(mem, mz, mctz);
442 spin_unlock(&mctz->lock);
446 static void mem_cgroup_update_tree(struct mem_cgroup *mem, struct page *page)
448 unsigned long long excess;
449 struct mem_cgroup_per_zone *mz;
450 struct mem_cgroup_tree_per_zone *mctz;
451 int nid = page_to_nid(page);
452 int zid = page_zonenum(page);
453 mctz = soft_limit_tree_from_page(page);
456 * Necessary to update all ancestors when hierarchy is used.
457 * because their event counter is not touched.
459 for (; mem; mem = parent_mem_cgroup(mem)) {
460 mz = mem_cgroup_zoneinfo(mem, nid, zid);
461 excess = res_counter_soft_limit_excess(&mem->res);
463 * We have to update the tree if mz is on RB-tree or
464 * mem is over its softlimit.
466 if (excess || mz->on_tree) {
467 spin_lock(&mctz->lock);
468 /* if on-tree, remove it */
470 __mem_cgroup_remove_exceeded(mem, mz, mctz);
472 * Insert again. mz->usage_in_excess will be updated.
473 * If excess is 0, no tree ops.
475 __mem_cgroup_insert_exceeded(mem, mz, mctz, excess);
476 spin_unlock(&mctz->lock);
481 static void mem_cgroup_remove_from_trees(struct mem_cgroup *mem)
484 struct mem_cgroup_per_zone *mz;
485 struct mem_cgroup_tree_per_zone *mctz;
487 for_each_node_state(node, N_POSSIBLE) {
488 for (zone = 0; zone < MAX_NR_ZONES; zone++) {
489 mz = mem_cgroup_zoneinfo(mem, node, zone);
490 mctz = soft_limit_tree_node_zone(node, zone);
491 mem_cgroup_remove_exceeded(mem, mz, mctz);
496 static struct mem_cgroup_per_zone *
497 __mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
499 struct rb_node *rightmost = NULL;
500 struct mem_cgroup_per_zone *mz;
504 rightmost = rb_last(&mctz->rb_root);
506 goto done; /* Nothing to reclaim from */
508 mz = rb_entry(rightmost, struct mem_cgroup_per_zone, tree_node);
510 * Remove the node now but someone else can add it back,
511 * we will to add it back at the end of reclaim to its correct
512 * position in the tree.
514 __mem_cgroup_remove_exceeded(mz->mem, mz, mctz);
515 if (!res_counter_soft_limit_excess(&mz->mem->res) ||
516 !css_tryget(&mz->mem->css))
522 static struct mem_cgroup_per_zone *
523 mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
525 struct mem_cgroup_per_zone *mz;
527 spin_lock(&mctz->lock);
528 mz = __mem_cgroup_largest_soft_limit_node(mctz);
529 spin_unlock(&mctz->lock);
534 * Implementation Note: reading percpu statistics for memcg.
536 * Both of vmstat[] and percpu_counter has threshold and do periodic
537 * synchronization to implement "quick" read. There are trade-off between
538 * reading cost and precision of value. Then, we may have a chance to implement
539 * a periodic synchronizion of counter in memcg's counter.
541 * But this _read() function is used for user interface now. The user accounts
542 * memory usage by memory cgroup and he _always_ requires exact value because
543 * he accounts memory. Even if we provide quick-and-fuzzy read, we always
544 * have to visit all online cpus and make sum. So, for now, unnecessary
545 * synchronization is not implemented. (just implemented for cpu hotplug)
547 * If there are kernel internal actions which can make use of some not-exact
548 * value, and reading all cpu value can be performance bottleneck in some
549 * common workload, threashold and synchonization as vmstat[] should be
552 static s64 mem_cgroup_read_stat(struct mem_cgroup *mem,
553 enum mem_cgroup_stat_index idx)
559 for_each_online_cpu(cpu)
560 val += per_cpu(mem->stat->count[idx], cpu);
561 #ifdef CONFIG_HOTPLUG_CPU
562 spin_lock(&mem->pcp_counter_lock);
563 val += mem->nocpu_base.count[idx];
564 spin_unlock(&mem->pcp_counter_lock);
570 static s64 mem_cgroup_local_usage(struct mem_cgroup *mem)
574 ret = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_RSS);
575 ret += mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_CACHE);
579 static void mem_cgroup_swap_statistics(struct mem_cgroup *mem,
582 int val = (charge) ? 1 : -1;
583 this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_SWAPOUT], val);
586 static void mem_cgroup_charge_statistics(struct mem_cgroup *mem,
587 bool file, int nr_pages)
592 __this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_CACHE], nr_pages);
594 __this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_RSS], nr_pages);
596 /* pagein of a big page is an event. So, ignore page size */
598 __this_cpu_inc(mem->stat->count[MEM_CGROUP_STAT_PGPGIN_COUNT]);
600 __this_cpu_inc(mem->stat->count[MEM_CGROUP_STAT_PGPGOUT_COUNT]);
601 nr_pages = -nr_pages; /* for event */
604 __this_cpu_add(mem->stat->count[MEM_CGROUP_EVENTS], nr_pages);
609 static unsigned long mem_cgroup_get_local_zonestat(struct mem_cgroup *mem,
613 struct mem_cgroup_per_zone *mz;
616 for_each_online_node(nid)
617 for (zid = 0; zid < MAX_NR_ZONES; zid++) {
618 mz = mem_cgroup_zoneinfo(mem, nid, zid);
619 total += MEM_CGROUP_ZSTAT(mz, idx);
624 static bool __memcg_event_check(struct mem_cgroup *mem, int event_mask_shift)
628 val = this_cpu_read(mem->stat->count[MEM_CGROUP_EVENTS]);
630 return !(val & ((1 << event_mask_shift) - 1));
634 * Check events in order.
637 static void memcg_check_events(struct mem_cgroup *mem, struct page *page)
639 /* threshold event is triggered in finer grain than soft limit */
640 if (unlikely(__memcg_event_check(mem, THRESHOLDS_EVENTS_THRESH))) {
641 mem_cgroup_threshold(mem);
642 if (unlikely(__memcg_event_check(mem, SOFTLIMIT_EVENTS_THRESH)))
643 mem_cgroup_update_tree(mem, page);
647 static struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont)
649 return container_of(cgroup_subsys_state(cont,
650 mem_cgroup_subsys_id), struct mem_cgroup,
654 struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
657 * mm_update_next_owner() may clear mm->owner to NULL
658 * if it races with swapoff, page migration, etc.
659 * So this can be called with p == NULL.
664 return container_of(task_subsys_state(p, mem_cgroup_subsys_id),
665 struct mem_cgroup, css);
668 static struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm)
670 struct mem_cgroup *mem = NULL;
675 * Because we have no locks, mm->owner's may be being moved to other
676 * cgroup. We use css_tryget() here even if this looks
677 * pessimistic (rather than adding locks here).
681 mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
684 } while (!css_tryget(&mem->css));
689 /* The caller has to guarantee "mem" exists before calling this */
690 static struct mem_cgroup *mem_cgroup_start_loop(struct mem_cgroup *mem)
692 struct cgroup_subsys_state *css;
695 if (!mem) /* ROOT cgroup has the smallest ID */
696 return root_mem_cgroup; /*css_put/get against root is ignored*/
697 if (!mem->use_hierarchy) {
698 if (css_tryget(&mem->css))
704 * searching a memory cgroup which has the smallest ID under given
705 * ROOT cgroup. (ID >= 1)
707 css = css_get_next(&mem_cgroup_subsys, 1, &mem->css, &found);
708 if (css && css_tryget(css))
709 mem = container_of(css, struct mem_cgroup, css);
716 static struct mem_cgroup *mem_cgroup_get_next(struct mem_cgroup *iter,
717 struct mem_cgroup *root,
720 int nextid = css_id(&iter->css) + 1;
723 struct cgroup_subsys_state *css;
725 hierarchy_used = iter->use_hierarchy;
728 /* If no ROOT, walk all, ignore hierarchy */
729 if (!cond || (root && !hierarchy_used))
733 root = root_mem_cgroup;
739 css = css_get_next(&mem_cgroup_subsys, nextid,
741 if (css && css_tryget(css))
742 iter = container_of(css, struct mem_cgroup, css);
744 /* If css is NULL, no more cgroups will be found */
746 } while (css && !iter);
751 * for_eacn_mem_cgroup_tree() for visiting all cgroup under tree. Please
752 * be careful that "break" loop is not allowed. We have reference count.
753 * Instead of that modify "cond" to be false and "continue" to exit the loop.
755 #define for_each_mem_cgroup_tree_cond(iter, root, cond) \
756 for (iter = mem_cgroup_start_loop(root);\
758 iter = mem_cgroup_get_next(iter, root, cond))
760 #define for_each_mem_cgroup_tree(iter, root) \
761 for_each_mem_cgroup_tree_cond(iter, root, true)
763 #define for_each_mem_cgroup_all(iter) \
764 for_each_mem_cgroup_tree_cond(iter, NULL, true)
767 static inline bool mem_cgroup_is_root(struct mem_cgroup *mem)
769 return (mem == root_mem_cgroup);
773 * Following LRU functions are allowed to be used without PCG_LOCK.
774 * Operations are called by routine of global LRU independently from memcg.
775 * What we have to take care of here is validness of pc->mem_cgroup.
777 * Changes to pc->mem_cgroup happens when
780 * In typical case, "charge" is done before add-to-lru. Exception is SwapCache.
781 * It is added to LRU before charge.
782 * If PCG_USED bit is not set, page_cgroup is not added to this private LRU.
783 * When moving account, the page is not on LRU. It's isolated.
786 void mem_cgroup_del_lru_list(struct page *page, enum lru_list lru)
788 struct page_cgroup *pc;
789 struct mem_cgroup_per_zone *mz;
791 if (mem_cgroup_disabled())
793 pc = lookup_page_cgroup(page);
794 /* can happen while we handle swapcache. */
795 if (!TestClearPageCgroupAcctLRU(pc))
797 VM_BUG_ON(!pc->mem_cgroup);
799 * We don't check PCG_USED bit. It's cleared when the "page" is finally
800 * removed from global LRU.
802 mz = page_cgroup_zoneinfo(pc->mem_cgroup, page);
803 /* huge page split is done under lru_lock. so, we have no races. */
804 MEM_CGROUP_ZSTAT(mz, lru) -= 1 << compound_order(page);
805 if (mem_cgroup_is_root(pc->mem_cgroup))
807 VM_BUG_ON(list_empty(&pc->lru));
808 list_del_init(&pc->lru);
811 void mem_cgroup_del_lru(struct page *page)
813 mem_cgroup_del_lru_list(page, page_lru(page));
817 * Writeback is about to end against a page which has been marked for immediate
818 * reclaim. If it still appears to be reclaimable, move it to the tail of the
821 void mem_cgroup_rotate_reclaimable_page(struct page *page)
823 struct mem_cgroup_per_zone *mz;
824 struct page_cgroup *pc;
825 enum lru_list lru = page_lru(page);
827 if (mem_cgroup_disabled())
830 pc = lookup_page_cgroup(page);
831 /* unused or root page is not rotated. */
832 if (!PageCgroupUsed(pc))
834 /* Ensure pc->mem_cgroup is visible after reading PCG_USED. */
836 if (mem_cgroup_is_root(pc->mem_cgroup))
838 mz = page_cgroup_zoneinfo(pc->mem_cgroup, page);
839 list_move_tail(&pc->lru, &mz->lists[lru]);
842 void mem_cgroup_rotate_lru_list(struct page *page, enum lru_list lru)
844 struct mem_cgroup_per_zone *mz;
845 struct page_cgroup *pc;
847 if (mem_cgroup_disabled())
850 pc = lookup_page_cgroup(page);
851 /* unused or root page is not rotated. */
852 if (!PageCgroupUsed(pc))
854 /* Ensure pc->mem_cgroup is visible after reading PCG_USED. */
856 if (mem_cgroup_is_root(pc->mem_cgroup))
858 mz = page_cgroup_zoneinfo(pc->mem_cgroup, page);
859 list_move(&pc->lru, &mz->lists[lru]);
862 void mem_cgroup_add_lru_list(struct page *page, enum lru_list lru)
864 struct page_cgroup *pc;
865 struct mem_cgroup_per_zone *mz;
867 if (mem_cgroup_disabled())
869 pc = lookup_page_cgroup(page);
870 VM_BUG_ON(PageCgroupAcctLRU(pc));
871 if (!PageCgroupUsed(pc))
873 /* Ensure pc->mem_cgroup is visible after reading PCG_USED. */
875 mz = page_cgroup_zoneinfo(pc->mem_cgroup, page);
876 /* huge page split is done under lru_lock. so, we have no races. */
877 MEM_CGROUP_ZSTAT(mz, lru) += 1 << compound_order(page);
878 SetPageCgroupAcctLRU(pc);
879 if (mem_cgroup_is_root(pc->mem_cgroup))
881 list_add(&pc->lru, &mz->lists[lru]);
885 * At handling SwapCache, pc->mem_cgroup may be changed while it's linked to
886 * lru because the page may.be reused after it's fully uncharged (because of
887 * SwapCache behavior).To handle that, unlink page_cgroup from LRU when charge
888 * it again. This function is only used to charge SwapCache. It's done under
889 * lock_page and expected that zone->lru_lock is never held.
891 static void mem_cgroup_lru_del_before_commit_swapcache(struct page *page)
894 struct zone *zone = page_zone(page);
895 struct page_cgroup *pc = lookup_page_cgroup(page);
897 spin_lock_irqsave(&zone->lru_lock, flags);
899 * Forget old LRU when this page_cgroup is *not* used. This Used bit
900 * is guarded by lock_page() because the page is SwapCache.
902 if (!PageCgroupUsed(pc))
903 mem_cgroup_del_lru_list(page, page_lru(page));
904 spin_unlock_irqrestore(&zone->lru_lock, flags);
907 static void mem_cgroup_lru_add_after_commit_swapcache(struct page *page)
910 struct zone *zone = page_zone(page);
911 struct page_cgroup *pc = lookup_page_cgroup(page);
913 spin_lock_irqsave(&zone->lru_lock, flags);
914 /* link when the page is linked to LRU but page_cgroup isn't */
915 if (PageLRU(page) && !PageCgroupAcctLRU(pc))
916 mem_cgroup_add_lru_list(page, page_lru(page));
917 spin_unlock_irqrestore(&zone->lru_lock, flags);
921 void mem_cgroup_move_lists(struct page *page,
922 enum lru_list from, enum lru_list to)
924 if (mem_cgroup_disabled())
926 mem_cgroup_del_lru_list(page, from);
927 mem_cgroup_add_lru_list(page, to);
930 int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem)
933 struct mem_cgroup *curr = NULL;
934 struct task_struct *p;
936 p = find_lock_task_mm(task);
939 curr = try_get_mem_cgroup_from_mm(p->mm);
944 * We should check use_hierarchy of "mem" not "curr". Because checking
945 * use_hierarchy of "curr" here make this function true if hierarchy is
946 * enabled in "curr" and "curr" is a child of "mem" in *cgroup*
947 * hierarchy(even if use_hierarchy is disabled in "mem").
949 if (mem->use_hierarchy)
950 ret = css_is_ancestor(&curr->css, &mem->css);
957 static int calc_inactive_ratio(struct mem_cgroup *memcg, unsigned long *present_pages)
959 unsigned long active;
960 unsigned long inactive;
962 unsigned long inactive_ratio;
964 inactive = mem_cgroup_get_local_zonestat(memcg, LRU_INACTIVE_ANON);
965 active = mem_cgroup_get_local_zonestat(memcg, LRU_ACTIVE_ANON);
967 gb = (inactive + active) >> (30 - PAGE_SHIFT);
969 inactive_ratio = int_sqrt(10 * gb);
974 present_pages[0] = inactive;
975 present_pages[1] = active;
978 return inactive_ratio;
981 int mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg)
983 unsigned long active;
984 unsigned long inactive;
985 unsigned long present_pages[2];
986 unsigned long inactive_ratio;
988 inactive_ratio = calc_inactive_ratio(memcg, present_pages);
990 inactive = present_pages[0];
991 active = present_pages[1];
993 if (inactive * inactive_ratio < active)
999 int mem_cgroup_inactive_file_is_low(struct mem_cgroup *memcg)
1001 unsigned long active;
1002 unsigned long inactive;
1004 inactive = mem_cgroup_get_local_zonestat(memcg, LRU_INACTIVE_FILE);
1005 active = mem_cgroup_get_local_zonestat(memcg, LRU_ACTIVE_FILE);
1007 return (active > inactive);
1010 unsigned long mem_cgroup_zone_nr_pages(struct mem_cgroup *memcg,
1014 int nid = zone_to_nid(zone);
1015 int zid = zone_idx(zone);
1016 struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid);
1018 return MEM_CGROUP_ZSTAT(mz, lru);
1021 struct zone_reclaim_stat *mem_cgroup_get_reclaim_stat(struct mem_cgroup *memcg,
1024 int nid = zone_to_nid(zone);
1025 int zid = zone_idx(zone);
1026 struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid);
1028 return &mz->reclaim_stat;
1031 struct zone_reclaim_stat *
1032 mem_cgroup_get_reclaim_stat_from_page(struct page *page)
1034 struct page_cgroup *pc;
1035 struct mem_cgroup_per_zone *mz;
1037 if (mem_cgroup_disabled())
1040 pc = lookup_page_cgroup(page);
1041 if (!PageCgroupUsed(pc))
1043 /* Ensure pc->mem_cgroup is visible after reading PCG_USED. */
1045 mz = page_cgroup_zoneinfo(pc->mem_cgroup, page);
1046 return &mz->reclaim_stat;
1049 unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
1050 struct list_head *dst,
1051 unsigned long *scanned, int order,
1052 int mode, struct zone *z,
1053 struct mem_cgroup *mem_cont,
1054 int active, int file)
1056 unsigned long nr_taken = 0;
1060 struct list_head *src;
1061 struct page_cgroup *pc, *tmp;
1062 int nid = zone_to_nid(z);
1063 int zid = zone_idx(z);
1064 struct mem_cgroup_per_zone *mz;
1065 int lru = LRU_FILE * file + active;
1069 mz = mem_cgroup_zoneinfo(mem_cont, nid, zid);
1070 src = &mz->lists[lru];
1073 list_for_each_entry_safe_reverse(pc, tmp, src, lru) {
1074 if (scan >= nr_to_scan)
1077 if (unlikely(!PageCgroupUsed(pc)))
1080 page = lookup_cgroup_page(pc);
1082 if (unlikely(!PageLRU(page)))
1086 ret = __isolate_lru_page(page, mode, file);
1089 list_move(&page->lru, dst);
1090 mem_cgroup_del_lru(page);
1091 nr_taken += hpage_nr_pages(page);
1094 /* we don't affect global LRU but rotate in our LRU */
1095 mem_cgroup_rotate_lru_list(page, page_lru(page));
1104 trace_mm_vmscan_memcg_isolate(0, nr_to_scan, scan, nr_taken,
1110 #define mem_cgroup_from_res_counter(counter, member) \
1111 container_of(counter, struct mem_cgroup, member)
1114 * mem_cgroup_margin - calculate chargeable space of a memory cgroup
1115 * @mem: the memory cgroup
1117 * Returns the maximum amount of memory @mem can be charged with, in
1120 static unsigned long long mem_cgroup_margin(struct mem_cgroup *mem)
1122 unsigned long long margin;
1124 margin = res_counter_margin(&mem->res);
1125 if (do_swap_account)
1126 margin = min(margin, res_counter_margin(&mem->memsw));
1130 static unsigned int get_swappiness(struct mem_cgroup *memcg)
1132 struct cgroup *cgrp = memcg->css.cgroup;
1133 unsigned int swappiness;
1136 if (cgrp->parent == NULL)
1137 return vm_swappiness;
1139 spin_lock(&memcg->reclaim_param_lock);
1140 swappiness = memcg->swappiness;
1141 spin_unlock(&memcg->reclaim_param_lock);
1146 static void mem_cgroup_start_move(struct mem_cgroup *mem)
1151 spin_lock(&mem->pcp_counter_lock);
1152 for_each_online_cpu(cpu)
1153 per_cpu(mem->stat->count[MEM_CGROUP_ON_MOVE], cpu) += 1;
1154 mem->nocpu_base.count[MEM_CGROUP_ON_MOVE] += 1;
1155 spin_unlock(&mem->pcp_counter_lock);
1161 static void mem_cgroup_end_move(struct mem_cgroup *mem)
1168 spin_lock(&mem->pcp_counter_lock);
1169 for_each_online_cpu(cpu)
1170 per_cpu(mem->stat->count[MEM_CGROUP_ON_MOVE], cpu) -= 1;
1171 mem->nocpu_base.count[MEM_CGROUP_ON_MOVE] -= 1;
1172 spin_unlock(&mem->pcp_counter_lock);
1176 * 2 routines for checking "mem" is under move_account() or not.
1178 * mem_cgroup_stealed() - checking a cgroup is mc.from or not. This is used
1179 * for avoiding race in accounting. If true,
1180 * pc->mem_cgroup may be overwritten.
1182 * mem_cgroup_under_move() - checking a cgroup is mc.from or mc.to or
1183 * under hierarchy of moving cgroups. This is for
1184 * waiting at hith-memory prressure caused by "move".
1187 static bool mem_cgroup_stealed(struct mem_cgroup *mem)
1189 VM_BUG_ON(!rcu_read_lock_held());
1190 return this_cpu_read(mem->stat->count[MEM_CGROUP_ON_MOVE]) > 0;
1193 static bool mem_cgroup_under_move(struct mem_cgroup *mem)
1195 struct mem_cgroup *from;
1196 struct mem_cgroup *to;
1199 * Unlike task_move routines, we access mc.to, mc.from not under
1200 * mutual exclusion by cgroup_mutex. Here, we take spinlock instead.
1202 spin_lock(&mc.lock);
1207 if (from == mem || to == mem
1208 || (mem->use_hierarchy && css_is_ancestor(&from->css, &mem->css))
1209 || (mem->use_hierarchy && css_is_ancestor(&to->css, &mem->css)))
1212 spin_unlock(&mc.lock);
1216 static bool mem_cgroup_wait_acct_move(struct mem_cgroup *mem)
1218 if (mc.moving_task && current != mc.moving_task) {
1219 if (mem_cgroup_under_move(mem)) {
1221 prepare_to_wait(&mc.waitq, &wait, TASK_INTERRUPTIBLE);
1222 /* moving charge context might have finished. */
1225 finish_wait(&mc.waitq, &wait);
1233 * mem_cgroup_print_oom_info: Called from OOM with tasklist_lock held in read mode.
1234 * @memcg: The memory cgroup that went over limit
1235 * @p: Task that is going to be killed
1237 * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is
1240 void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
1242 struct cgroup *task_cgrp;
1243 struct cgroup *mem_cgrp;
1245 * Need a buffer in BSS, can't rely on allocations. The code relies
1246 * on the assumption that OOM is serialized for memory controller.
1247 * If this assumption is broken, revisit this code.
1249 static char memcg_name[PATH_MAX];
1258 mem_cgrp = memcg->css.cgroup;
1259 task_cgrp = task_cgroup(p, mem_cgroup_subsys_id);
1261 ret = cgroup_path(task_cgrp, memcg_name, PATH_MAX);
1264 * Unfortunately, we are unable to convert to a useful name
1265 * But we'll still print out the usage information
1272 printk(KERN_INFO "Task in %s killed", memcg_name);
1275 ret = cgroup_path(mem_cgrp, memcg_name, PATH_MAX);
1283 * Continues from above, so we don't need an KERN_ level
1285 printk(KERN_CONT " as a result of limit of %s\n", memcg_name);
1288 printk(KERN_INFO "memory: usage %llukB, limit %llukB, failcnt %llu\n",
1289 res_counter_read_u64(&memcg->res, RES_USAGE) >> 10,
1290 res_counter_read_u64(&memcg->res, RES_LIMIT) >> 10,
1291 res_counter_read_u64(&memcg->res, RES_FAILCNT));
1292 printk(KERN_INFO "memory+swap: usage %llukB, limit %llukB, "
1294 res_counter_read_u64(&memcg->memsw, RES_USAGE) >> 10,
1295 res_counter_read_u64(&memcg->memsw, RES_LIMIT) >> 10,
1296 res_counter_read_u64(&memcg->memsw, RES_FAILCNT));
1300 * This function returns the number of memcg under hierarchy tree. Returns
1301 * 1(self count) if no children.
1303 static int mem_cgroup_count_children(struct mem_cgroup *mem)
1306 struct mem_cgroup *iter;
1308 for_each_mem_cgroup_tree(iter, mem)
1314 * Return the memory (and swap, if configured) limit for a memcg.
1316 u64 mem_cgroup_get_limit(struct mem_cgroup *memcg)
1321 limit = res_counter_read_u64(&memcg->res, RES_LIMIT);
1322 limit += total_swap_pages << PAGE_SHIFT;
1324 memsw = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
1326 * If memsw is finite and limits the amount of swap space available
1327 * to this memcg, return that limit.
1329 return min(limit, memsw);
1333 * Visit the first child (need not be the first child as per the ordering
1334 * of the cgroup list, since we track last_scanned_child) of @mem and use
1335 * that to reclaim free pages from.
1337 static struct mem_cgroup *
1338 mem_cgroup_select_victim(struct mem_cgroup *root_mem)
1340 struct mem_cgroup *ret = NULL;
1341 struct cgroup_subsys_state *css;
1344 if (!root_mem->use_hierarchy) {
1345 css_get(&root_mem->css);
1351 nextid = root_mem->last_scanned_child + 1;
1352 css = css_get_next(&mem_cgroup_subsys, nextid, &root_mem->css,
1354 if (css && css_tryget(css))
1355 ret = container_of(css, struct mem_cgroup, css);
1358 /* Updates scanning parameter */
1359 spin_lock(&root_mem->reclaim_param_lock);
1361 /* this means start scan from ID:1 */
1362 root_mem->last_scanned_child = 0;
1364 root_mem->last_scanned_child = found;
1365 spin_unlock(&root_mem->reclaim_param_lock);
1372 * Scan the hierarchy if needed to reclaim memory. We remember the last child
1373 * we reclaimed from, so that we don't end up penalizing one child extensively
1374 * based on its position in the children list.
1376 * root_mem is the original ancestor that we've been reclaim from.
1378 * We give up and return to the caller when we visit root_mem twice.
1379 * (other groups can be removed while we're walking....)
1381 * If shrink==true, for avoiding to free too much, this returns immedieately.
1383 static int mem_cgroup_hierarchical_reclaim(struct mem_cgroup *root_mem,
1386 unsigned long reclaim_options)
1388 struct mem_cgroup *victim;
1391 bool noswap = reclaim_options & MEM_CGROUP_RECLAIM_NOSWAP;
1392 bool shrink = reclaim_options & MEM_CGROUP_RECLAIM_SHRINK;
1393 bool check_soft = reclaim_options & MEM_CGROUP_RECLAIM_SOFT;
1394 unsigned long excess;
1396 excess = res_counter_soft_limit_excess(&root_mem->res) >> PAGE_SHIFT;
1398 /* If memsw_is_minimum==1, swap-out is of-no-use. */
1399 if (root_mem->memsw_is_minimum)
1403 victim = mem_cgroup_select_victim(root_mem);
1404 if (victim == root_mem) {
1407 drain_all_stock_async();
1410 * If we have not been able to reclaim
1411 * anything, it might because there are
1412 * no reclaimable pages under this hierarchy
1414 if (!check_soft || !total) {
1415 css_put(&victim->css);
1419 * We want to do more targetted reclaim.
1420 * excess >> 2 is not to excessive so as to
1421 * reclaim too much, nor too less that we keep
1422 * coming back to reclaim from this cgroup
1424 if (total >= (excess >> 2) ||
1425 (loop > MEM_CGROUP_MAX_RECLAIM_LOOPS)) {
1426 css_put(&victim->css);
1431 if (!mem_cgroup_local_usage(victim)) {
1432 /* this cgroup's local usage == 0 */
1433 css_put(&victim->css);
1436 /* we use swappiness of local cgroup */
1438 ret = mem_cgroup_shrink_node_zone(victim, gfp_mask,
1439 noswap, get_swappiness(victim), zone);
1441 ret = try_to_free_mem_cgroup_pages(victim, gfp_mask,
1442 noswap, get_swappiness(victim));
1443 css_put(&victim->css);
1445 * At shrinking usage, we can't check we should stop here or
1446 * reclaim more. It's depends on callers. last_scanned_child
1447 * will work enough for keeping fairness under tree.
1453 if (!res_counter_soft_limit_excess(&root_mem->res))
1455 } else if (mem_cgroup_margin(root_mem))
1462 * Check OOM-Killer is already running under our hierarchy.
1463 * If someone is running, return false.
1465 static bool mem_cgroup_oom_lock(struct mem_cgroup *mem)
1467 int x, lock_count = 0;
1468 struct mem_cgroup *iter;
1470 for_each_mem_cgroup_tree(iter, mem) {
1471 x = atomic_inc_return(&iter->oom_lock);
1472 lock_count = max(x, lock_count);
1475 if (lock_count == 1)
1480 static int mem_cgroup_oom_unlock(struct mem_cgroup *mem)
1482 struct mem_cgroup *iter;
1485 * When a new child is created while the hierarchy is under oom,
1486 * mem_cgroup_oom_lock() may not be called. We have to use
1487 * atomic_add_unless() here.
1489 for_each_mem_cgroup_tree(iter, mem)
1490 atomic_add_unless(&iter->oom_lock, -1, 0);
1495 static DEFINE_MUTEX(memcg_oom_mutex);
1496 static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq);
1498 struct oom_wait_info {
1499 struct mem_cgroup *mem;
1503 static int memcg_oom_wake_function(wait_queue_t *wait,
1504 unsigned mode, int sync, void *arg)
1506 struct mem_cgroup *wake_mem = (struct mem_cgroup *)arg;
1507 struct oom_wait_info *oom_wait_info;
1509 oom_wait_info = container_of(wait, struct oom_wait_info, wait);
1511 if (oom_wait_info->mem == wake_mem)
1513 /* if no hierarchy, no match */
1514 if (!oom_wait_info->mem->use_hierarchy || !wake_mem->use_hierarchy)
1517 * Both of oom_wait_info->mem and wake_mem are stable under us.
1518 * Then we can use css_is_ancestor without taking care of RCU.
1520 if (!css_is_ancestor(&oom_wait_info->mem->css, &wake_mem->css) &&
1521 !css_is_ancestor(&wake_mem->css, &oom_wait_info->mem->css))
1525 return autoremove_wake_function(wait, mode, sync, arg);
1528 static void memcg_wakeup_oom(struct mem_cgroup *mem)
1530 /* for filtering, pass "mem" as argument. */
1531 __wake_up(&memcg_oom_waitq, TASK_NORMAL, 0, mem);
1534 static void memcg_oom_recover(struct mem_cgroup *mem)
1536 if (mem && atomic_read(&mem->oom_lock))
1537 memcg_wakeup_oom(mem);
1541 * try to call OOM killer. returns false if we should exit memory-reclaim loop.
1543 bool mem_cgroup_handle_oom(struct mem_cgroup *mem, gfp_t mask)
1545 struct oom_wait_info owait;
1546 bool locked, need_to_kill;
1549 owait.wait.flags = 0;
1550 owait.wait.func = memcg_oom_wake_function;
1551 owait.wait.private = current;
1552 INIT_LIST_HEAD(&owait.wait.task_list);
1553 need_to_kill = true;
1554 /* At first, try to OOM lock hierarchy under mem.*/
1555 mutex_lock(&memcg_oom_mutex);
1556 locked = mem_cgroup_oom_lock(mem);
1558 * Even if signal_pending(), we can't quit charge() loop without
1559 * accounting. So, UNINTERRUPTIBLE is appropriate. But SIGKILL
1560 * under OOM is always welcomed, use TASK_KILLABLE here.
1562 prepare_to_wait(&memcg_oom_waitq, &owait.wait, TASK_KILLABLE);
1563 if (!locked || mem->oom_kill_disable)
1564 need_to_kill = false;
1566 mem_cgroup_oom_notify(mem);
1567 mutex_unlock(&memcg_oom_mutex);
1570 finish_wait(&memcg_oom_waitq, &owait.wait);
1571 mem_cgroup_out_of_memory(mem, mask);
1574 finish_wait(&memcg_oom_waitq, &owait.wait);
1576 mutex_lock(&memcg_oom_mutex);
1577 mem_cgroup_oom_unlock(mem);
1578 memcg_wakeup_oom(mem);
1579 mutex_unlock(&memcg_oom_mutex);
1581 if (test_thread_flag(TIF_MEMDIE) || fatal_signal_pending(current))
1583 /* Give chance to dying process */
1584 schedule_timeout(1);
1589 * Currently used to update mapped file statistics, but the routine can be
1590 * generalized to update other statistics as well.
1592 * Notes: Race condition
1594 * We usually use page_cgroup_lock() for accessing page_cgroup member but
1595 * it tends to be costly. But considering some conditions, we doesn't need
1596 * to do so _always_.
1598 * Considering "charge", lock_page_cgroup() is not required because all
1599 * file-stat operations happen after a page is attached to radix-tree. There
1600 * are no race with "charge".
1602 * Considering "uncharge", we know that memcg doesn't clear pc->mem_cgroup
1603 * at "uncharge" intentionally. So, we always see valid pc->mem_cgroup even
1604 * if there are race with "uncharge". Statistics itself is properly handled
1607 * Considering "move", this is an only case we see a race. To make the race
1608 * small, we check MEM_CGROUP_ON_MOVE percpu value and detect there are
1609 * possibility of race condition. If there is, we take a lock.
1612 void mem_cgroup_update_page_stat(struct page *page,
1613 enum mem_cgroup_page_stat_item idx, int val)
1615 struct mem_cgroup *mem;
1616 struct page_cgroup *pc = lookup_page_cgroup(page);
1617 bool need_unlock = false;
1618 unsigned long uninitialized_var(flags);
1624 mem = pc->mem_cgroup;
1625 if (unlikely(!mem || !PageCgroupUsed(pc)))
1627 /* pc->mem_cgroup is unstable ? */
1628 if (unlikely(mem_cgroup_stealed(mem)) || PageTransHuge(page)) {
1629 /* take a lock against to access pc->mem_cgroup */
1630 move_lock_page_cgroup(pc, &flags);
1632 mem = pc->mem_cgroup;
1633 if (!mem || !PageCgroupUsed(pc))
1638 case MEMCG_NR_FILE_MAPPED:
1640 SetPageCgroupFileMapped(pc);
1641 else if (!page_mapped(page))
1642 ClearPageCgroupFileMapped(pc);
1643 idx = MEM_CGROUP_STAT_FILE_MAPPED;
1649 this_cpu_add(mem->stat->count[idx], val);
1652 if (unlikely(need_unlock))
1653 move_unlock_page_cgroup(pc, &flags);
1657 EXPORT_SYMBOL(mem_cgroup_update_page_stat);
1660 * size of first charge trial. "32" comes from vmscan.c's magic value.
1661 * TODO: maybe necessary to use big numbers in big irons.
1663 #define CHARGE_SIZE (32 * PAGE_SIZE)
1664 struct memcg_stock_pcp {
1665 struct mem_cgroup *cached; /* this never be root cgroup */
1667 struct work_struct work;
1669 static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock);
1670 static atomic_t memcg_drain_count;
1673 * Try to consume stocked charge on this cpu. If success, PAGE_SIZE is consumed
1674 * from local stock and true is returned. If the stock is 0 or charges from a
1675 * cgroup which is not current target, returns false. This stock will be
1678 static bool consume_stock(struct mem_cgroup *mem)
1680 struct memcg_stock_pcp *stock;
1683 stock = &get_cpu_var(memcg_stock);
1684 if (mem == stock->cached && stock->charge)
1685 stock->charge -= PAGE_SIZE;
1686 else /* need to call res_counter_charge */
1688 put_cpu_var(memcg_stock);
1693 * Returns stocks cached in percpu to res_counter and reset cached information.
1695 static void drain_stock(struct memcg_stock_pcp *stock)
1697 struct mem_cgroup *old = stock->cached;
1699 if (stock->charge) {
1700 res_counter_uncharge(&old->res, stock->charge);
1701 if (do_swap_account)
1702 res_counter_uncharge(&old->memsw, stock->charge);
1704 stock->cached = NULL;
1709 * This must be called under preempt disabled or must be called by
1710 * a thread which is pinned to local cpu.
1712 static void drain_local_stock(struct work_struct *dummy)
1714 struct memcg_stock_pcp *stock = &__get_cpu_var(memcg_stock);
1719 * Cache charges(val) which is from res_counter, to local per_cpu area.
1720 * This will be consumed by consume_stock() function, later.
1722 static void refill_stock(struct mem_cgroup *mem, int val)
1724 struct memcg_stock_pcp *stock = &get_cpu_var(memcg_stock);
1726 if (stock->cached != mem) { /* reset if necessary */
1728 stock->cached = mem;
1730 stock->charge += val;
1731 put_cpu_var(memcg_stock);
1735 * Tries to drain stocked charges in other cpus. This function is asynchronous
1736 * and just put a work per cpu for draining localy on each cpu. Caller can
1737 * expects some charges will be back to res_counter later but cannot wait for
1740 static void drain_all_stock_async(void)
1743 /* This function is for scheduling "drain" in asynchronous way.
1744 * The result of "drain" is not directly handled by callers. Then,
1745 * if someone is calling drain, we don't have to call drain more.
1746 * Anyway, WORK_STRUCT_PENDING check in queue_work_on() will catch if
1747 * there is a race. We just do loose check here.
1749 if (atomic_read(&memcg_drain_count))
1751 /* Notify other cpus that system-wide "drain" is running */
1752 atomic_inc(&memcg_drain_count);
1754 for_each_online_cpu(cpu) {
1755 struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
1756 schedule_work_on(cpu, &stock->work);
1759 atomic_dec(&memcg_drain_count);
1760 /* We don't wait for flush_work */
1763 /* This is a synchronous drain interface. */
1764 static void drain_all_stock_sync(void)
1766 /* called when force_empty is called */
1767 atomic_inc(&memcg_drain_count);
1768 schedule_on_each_cpu(drain_local_stock);
1769 atomic_dec(&memcg_drain_count);
1773 * This function drains percpu counter value from DEAD cpu and
1774 * move it to local cpu. Note that this function can be preempted.
1776 static void mem_cgroup_drain_pcp_counter(struct mem_cgroup *mem, int cpu)
1780 spin_lock(&mem->pcp_counter_lock);
1781 for (i = 0; i < MEM_CGROUP_STAT_DATA; i++) {
1782 s64 x = per_cpu(mem->stat->count[i], cpu);
1784 per_cpu(mem->stat->count[i], cpu) = 0;
1785 mem->nocpu_base.count[i] += x;
1787 /* need to clear ON_MOVE value, works as a kind of lock. */
1788 per_cpu(mem->stat->count[MEM_CGROUP_ON_MOVE], cpu) = 0;
1789 spin_unlock(&mem->pcp_counter_lock);
1792 static void synchronize_mem_cgroup_on_move(struct mem_cgroup *mem, int cpu)
1794 int idx = MEM_CGROUP_ON_MOVE;
1796 spin_lock(&mem->pcp_counter_lock);
1797 per_cpu(mem->stat->count[idx], cpu) = mem->nocpu_base.count[idx];
1798 spin_unlock(&mem->pcp_counter_lock);
1801 static int __cpuinit memcg_cpu_hotplug_callback(struct notifier_block *nb,
1802 unsigned long action,
1805 int cpu = (unsigned long)hcpu;
1806 struct memcg_stock_pcp *stock;
1807 struct mem_cgroup *iter;
1809 if ((action == CPU_ONLINE)) {
1810 for_each_mem_cgroup_all(iter)
1811 synchronize_mem_cgroup_on_move(iter, cpu);
1815 if ((action != CPU_DEAD) || action != CPU_DEAD_FROZEN)
1818 for_each_mem_cgroup_all(iter)
1819 mem_cgroup_drain_pcp_counter(iter, cpu);
1821 stock = &per_cpu(memcg_stock, cpu);
1827 /* See __mem_cgroup_try_charge() for details */
1829 CHARGE_OK, /* success */
1830 CHARGE_RETRY, /* need to retry but retry is not bad */
1831 CHARGE_NOMEM, /* we can't do more. return -ENOMEM */
1832 CHARGE_WOULDBLOCK, /* GFP_WAIT wasn't set and no enough res. */
1833 CHARGE_OOM_DIE, /* the current is killed because of OOM */
1836 static int __mem_cgroup_do_charge(struct mem_cgroup *mem, gfp_t gfp_mask,
1837 int csize, bool oom_check)
1839 struct mem_cgroup *mem_over_limit;
1840 struct res_counter *fail_res;
1841 unsigned long flags = 0;
1844 ret = res_counter_charge(&mem->res, csize, &fail_res);
1847 if (!do_swap_account)
1849 ret = res_counter_charge(&mem->memsw, csize, &fail_res);
1853 res_counter_uncharge(&mem->res, csize);
1854 mem_over_limit = mem_cgroup_from_res_counter(fail_res, memsw);
1855 flags |= MEM_CGROUP_RECLAIM_NOSWAP;
1857 mem_over_limit = mem_cgroup_from_res_counter(fail_res, res);
1859 * csize can be either a huge page (HPAGE_SIZE), a batch of
1860 * regular pages (CHARGE_SIZE), or a single regular page
1863 * Never reclaim on behalf of optional batching, retry with a
1864 * single page instead.
1866 if (csize == CHARGE_SIZE)
1867 return CHARGE_RETRY;
1869 if (!(gfp_mask & __GFP_WAIT))
1870 return CHARGE_WOULDBLOCK;
1872 ret = mem_cgroup_hierarchical_reclaim(mem_over_limit, NULL,
1874 if (mem_cgroup_margin(mem_over_limit) >= csize)
1875 return CHARGE_RETRY;
1877 * Even though the limit is exceeded at this point, reclaim
1878 * may have been able to free some pages. Retry the charge
1879 * before killing the task.
1881 * Only for regular pages, though: huge pages are rather
1882 * unlikely to succeed so close to the limit, and we fall back
1883 * to regular pages anyway in case of failure.
1885 if (csize == PAGE_SIZE && ret)
1886 return CHARGE_RETRY;
1889 * At task move, charge accounts can be doubly counted. So, it's
1890 * better to wait until the end of task_move if something is going on.
1892 if (mem_cgroup_wait_acct_move(mem_over_limit))
1893 return CHARGE_RETRY;
1895 /* If we don't need to call oom-killer at el, return immediately */
1897 return CHARGE_NOMEM;
1899 if (!mem_cgroup_handle_oom(mem_over_limit, gfp_mask))
1900 return CHARGE_OOM_DIE;
1902 return CHARGE_RETRY;
1906 * Unlike exported interface, "oom" parameter is added. if oom==true,
1907 * oom-killer can be invoked.
1909 static int __mem_cgroup_try_charge(struct mm_struct *mm,
1911 struct mem_cgroup **memcg, bool oom,
1914 int nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES;
1915 struct mem_cgroup *mem = NULL;
1917 int csize = max(CHARGE_SIZE, (unsigned long) page_size);
1920 * Unlike gloval-vm's OOM-kill, we're not in memory shortage
1921 * in system level. So, allow to go ahead dying process in addition to
1924 if (unlikely(test_thread_flag(TIF_MEMDIE)
1925 || fatal_signal_pending(current)))
1929 * We always charge the cgroup the mm_struct belongs to.
1930 * The mm_struct's mem_cgroup changes on task migration if the
1931 * thread group leader migrates. It's possible that mm is not
1932 * set, if so charge the init_mm (happens for pagecache usage).
1937 if (*memcg) { /* css should be a valid one */
1939 VM_BUG_ON(css_is_removed(&mem->css));
1940 if (mem_cgroup_is_root(mem))
1942 if (page_size == PAGE_SIZE && consume_stock(mem))
1946 struct task_struct *p;
1949 p = rcu_dereference(mm->owner);
1951 * Because we don't have task_lock(), "p" can exit.
1952 * In that case, "mem" can point to root or p can be NULL with
1953 * race with swapoff. Then, we have small risk of mis-accouning.
1954 * But such kind of mis-account by race always happens because
1955 * we don't have cgroup_mutex(). It's overkill and we allo that
1957 * (*) swapoff at el will charge against mm-struct not against
1958 * task-struct. So, mm->owner can be NULL.
1960 mem = mem_cgroup_from_task(p);
1961 if (!mem || mem_cgroup_is_root(mem)) {
1965 if (page_size == PAGE_SIZE && consume_stock(mem)) {
1967 * It seems dagerous to access memcg without css_get().
1968 * But considering how consume_stok works, it's not
1969 * necessary. If consume_stock success, some charges
1970 * from this memcg are cached on this cpu. So, we
1971 * don't need to call css_get()/css_tryget() before
1972 * calling consume_stock().
1977 /* after here, we may be blocked. we need to get refcnt */
1978 if (!css_tryget(&mem->css)) {
1988 /* If killed, bypass charge */
1989 if (fatal_signal_pending(current)) {
1995 if (oom && !nr_oom_retries) {
1997 nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES;
2000 ret = __mem_cgroup_do_charge(mem, gfp_mask, csize, oom_check);
2005 case CHARGE_RETRY: /* not in OOM situation but retry */
2010 case CHARGE_WOULDBLOCK: /* !__GFP_WAIT */
2013 case CHARGE_NOMEM: /* OOM routine works */
2018 /* If oom, we never return -ENOMEM */
2021 case CHARGE_OOM_DIE: /* Killed by OOM Killer */
2025 } while (ret != CHARGE_OK);
2027 if (csize > page_size)
2028 refill_stock(mem, csize - page_size);
2042 * Somemtimes we have to undo a charge we got by try_charge().
2043 * This function is for that and do uncharge, put css's refcnt.
2044 * gotten by try_charge().
2046 static void __mem_cgroup_cancel_charge(struct mem_cgroup *mem,
2047 unsigned long count)
2049 if (!mem_cgroup_is_root(mem)) {
2050 res_counter_uncharge(&mem->res, PAGE_SIZE * count);
2051 if (do_swap_account)
2052 res_counter_uncharge(&mem->memsw, PAGE_SIZE * count);
2056 static void mem_cgroup_cancel_charge(struct mem_cgroup *mem,
2059 __mem_cgroup_cancel_charge(mem, page_size >> PAGE_SHIFT);
2063 * A helper function to get mem_cgroup from ID. must be called under
2064 * rcu_read_lock(). The caller must check css_is_removed() or some if
2065 * it's concern. (dropping refcnt from swap can be called against removed
2068 static struct mem_cgroup *mem_cgroup_lookup(unsigned short id)
2070 struct cgroup_subsys_state *css;
2072 /* ID 0 is unused ID */
2075 css = css_lookup(&mem_cgroup_subsys, id);
2078 return container_of(css, struct mem_cgroup, css);
2081 struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page)
2083 struct mem_cgroup *mem = NULL;
2084 struct page_cgroup *pc;
2088 VM_BUG_ON(!PageLocked(page));
2090 pc = lookup_page_cgroup(page);
2091 lock_page_cgroup(pc);
2092 if (PageCgroupUsed(pc)) {
2093 mem = pc->mem_cgroup;
2094 if (mem && !css_tryget(&mem->css))
2096 } else if (PageSwapCache(page)) {
2097 ent.val = page_private(page);
2098 id = lookup_swap_cgroup(ent);
2100 mem = mem_cgroup_lookup(id);
2101 if (mem && !css_tryget(&mem->css))
2105 unlock_page_cgroup(pc);
2109 static void __mem_cgroup_commit_charge(struct mem_cgroup *mem,
2111 struct page_cgroup *pc,
2112 enum charge_type ctype,
2115 int nr_pages = page_size >> PAGE_SHIFT;
2117 lock_page_cgroup(pc);
2118 if (unlikely(PageCgroupUsed(pc))) {
2119 unlock_page_cgroup(pc);
2120 mem_cgroup_cancel_charge(mem, page_size);
2124 * we don't need page_cgroup_lock about tail pages, becase they are not
2125 * accessed by any other context at this point.
2127 pc->mem_cgroup = mem;
2129 * We access a page_cgroup asynchronously without lock_page_cgroup().
2130 * Especially when a page_cgroup is taken from a page, pc->mem_cgroup
2131 * is accessed after testing USED bit. To make pc->mem_cgroup visible
2132 * before USED bit, we need memory barrier here.
2133 * See mem_cgroup_add_lru_list(), etc.
2137 case MEM_CGROUP_CHARGE_TYPE_CACHE:
2138 case MEM_CGROUP_CHARGE_TYPE_SHMEM:
2139 SetPageCgroupCache(pc);
2140 SetPageCgroupUsed(pc);
2142 case MEM_CGROUP_CHARGE_TYPE_MAPPED:
2143 ClearPageCgroupCache(pc);
2144 SetPageCgroupUsed(pc);
2150 mem_cgroup_charge_statistics(mem, PageCgroupCache(pc), nr_pages);
2151 unlock_page_cgroup(pc);
2153 * "charge_statistics" updated event counter. Then, check it.
2154 * Insert ancestor (and ancestor's ancestors), to softlimit RB-tree.
2155 * if they exceeds softlimit.
2157 memcg_check_events(mem, page);
2160 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
2162 #define PCGF_NOCOPY_AT_SPLIT ((1 << PCG_LOCK) | (1 << PCG_MOVE_LOCK) |\
2163 (1 << PCG_ACCT_LRU) | (1 << PCG_MIGRATION))
2165 * Because tail pages are not marked as "used", set it. We're under
2166 * zone->lru_lock, 'splitting on pmd' and compund_lock.
2168 void mem_cgroup_split_huge_fixup(struct page *head, struct page *tail)
2170 struct page_cgroup *head_pc = lookup_page_cgroup(head);
2171 struct page_cgroup *tail_pc = lookup_page_cgroup(tail);
2172 unsigned long flags;
2174 if (mem_cgroup_disabled())
2177 * We have no races with charge/uncharge but will have races with
2178 * page state accounting.
2180 move_lock_page_cgroup(head_pc, &flags);
2182 tail_pc->mem_cgroup = head_pc->mem_cgroup;
2183 smp_wmb(); /* see __commit_charge() */
2184 if (PageCgroupAcctLRU(head_pc)) {
2186 struct mem_cgroup_per_zone *mz;
2189 * LRU flags cannot be copied because we need to add tail
2190 *.page to LRU by generic call and our hook will be called.
2191 * We hold lru_lock, then, reduce counter directly.
2193 lru = page_lru(head);
2194 mz = page_cgroup_zoneinfo(head_pc->mem_cgroup, head);
2195 MEM_CGROUP_ZSTAT(mz, lru) -= 1;
2197 tail_pc->flags = head_pc->flags & ~PCGF_NOCOPY_AT_SPLIT;
2198 move_unlock_page_cgroup(head_pc, &flags);
2203 * mem_cgroup_move_account - move account of the page
2205 * @pc: page_cgroup of the page.
2206 * @from: mem_cgroup which the page is moved from.
2207 * @to: mem_cgroup which the page is moved to. @from != @to.
2208 * @uncharge: whether we should call uncharge and css_put against @from.
2209 * @charge_size: number of bytes to charge (regular or huge page)
2211 * The caller must confirm following.
2212 * - page is not on LRU (isolate_page() is useful.)
2213 * - compound_lock is held when charge_size > PAGE_SIZE
2215 * This function doesn't do "charge" nor css_get to new cgroup. It should be
2216 * done by a caller(__mem_cgroup_try_charge would be usefull). If @uncharge is
2217 * true, this function does "uncharge" from old cgroup, but it doesn't if
2218 * @uncharge is false, so a caller should do "uncharge".
2220 static int mem_cgroup_move_account(struct page *page, struct page_cgroup *pc,
2221 struct mem_cgroup *from, struct mem_cgroup *to,
2222 bool uncharge, int charge_size)
2224 int nr_pages = charge_size >> PAGE_SHIFT;
2225 unsigned long flags;
2228 VM_BUG_ON(from == to);
2229 VM_BUG_ON(PageLRU(page));
2231 * The page is isolated from LRU. So, collapse function
2232 * will not handle this page. But page splitting can happen.
2233 * Do this check under compound_page_lock(). The caller should
2237 if (charge_size > PAGE_SIZE && !PageTransHuge(page))
2240 lock_page_cgroup(pc);
2243 if (!PageCgroupUsed(pc) || pc->mem_cgroup != from)
2246 move_lock_page_cgroup(pc, &flags);
2248 if (PageCgroupFileMapped(pc)) {
2249 /* Update mapped_file data for mem_cgroup */
2251 __this_cpu_dec(from->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]);
2252 __this_cpu_inc(to->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]);
2255 mem_cgroup_charge_statistics(from, PageCgroupCache(pc), -nr_pages);
2257 /* This is not "cancel", but cancel_charge does all we need. */
2258 mem_cgroup_cancel_charge(from, charge_size);
2260 /* caller should have done css_get */
2261 pc->mem_cgroup = to;
2262 mem_cgroup_charge_statistics(to, PageCgroupCache(pc), nr_pages);
2264 * We charges against "to" which may not have any tasks. Then, "to"
2265 * can be under rmdir(). But in current implementation, caller of
2266 * this function is just force_empty() and move charge, so it's
2267 * garanteed that "to" is never removed. So, we don't check rmdir
2270 move_unlock_page_cgroup(pc, &flags);
2273 unlock_page_cgroup(pc);
2277 memcg_check_events(to, page);
2278 memcg_check_events(from, page);
2284 * move charges to its parent.
2287 static int mem_cgroup_move_parent(struct page *page,
2288 struct page_cgroup *pc,
2289 struct mem_cgroup *child,
2292 struct cgroup *cg = child->css.cgroup;
2293 struct cgroup *pcg = cg->parent;
2294 struct mem_cgroup *parent;
2295 int page_size = PAGE_SIZE;
2296 unsigned long flags;
2304 if (!get_page_unless_zero(page))
2306 if (isolate_lru_page(page))
2309 if (PageTransHuge(page))
2310 page_size = HPAGE_SIZE;
2312 parent = mem_cgroup_from_cont(pcg);
2313 ret = __mem_cgroup_try_charge(NULL, gfp_mask,
2314 &parent, false, page_size);
2318 if (page_size > PAGE_SIZE)
2319 flags = compound_lock_irqsave(page);
2321 ret = mem_cgroup_move_account(page, pc, child, parent, true, page_size);
2323 mem_cgroup_cancel_charge(parent, page_size);
2325 if (page_size > PAGE_SIZE)
2326 compound_unlock_irqrestore(page, flags);
2328 putback_lru_page(page);
2336 * Charge the memory controller for page usage.
2338 * 0 if the charge was successful
2339 * < 0 if the cgroup is over its limit
2341 static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm,
2342 gfp_t gfp_mask, enum charge_type ctype)
2344 struct mem_cgroup *mem = NULL;
2345 int page_size = PAGE_SIZE;
2346 struct page_cgroup *pc;
2350 if (PageTransHuge(page)) {
2351 page_size <<= compound_order(page);
2352 VM_BUG_ON(!PageTransHuge(page));
2354 * Never OOM-kill a process for a huge page. The
2355 * fault handler will fall back to regular pages.
2360 pc = lookup_page_cgroup(page);
2361 BUG_ON(!pc); /* XXX: remove this and move pc lookup into commit */
2363 ret = __mem_cgroup_try_charge(mm, gfp_mask, &mem, oom, page_size);
2367 __mem_cgroup_commit_charge(mem, page, pc, ctype, page_size);
2371 int mem_cgroup_newpage_charge(struct page *page,
2372 struct mm_struct *mm, gfp_t gfp_mask)
2374 if (mem_cgroup_disabled())
2377 * If already mapped, we don't have to account.
2378 * If page cache, page->mapping has address_space.
2379 * But page->mapping may have out-of-use anon_vma pointer,
2380 * detecit it by PageAnon() check. newly-mapped-anon's page->mapping
2383 if (page_mapped(page) || (page->mapping && !PageAnon(page)))
2387 return mem_cgroup_charge_common(page, mm, gfp_mask,
2388 MEM_CGROUP_CHARGE_TYPE_MAPPED);
2392 __mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr,
2393 enum charge_type ctype);
2395 int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
2400 if (mem_cgroup_disabled())
2402 if (PageCompound(page))
2405 * Corner case handling. This is called from add_to_page_cache()
2406 * in usual. But some FS (shmem) precharges this page before calling it
2407 * and call add_to_page_cache() with GFP_NOWAIT.
2409 * For GFP_NOWAIT case, the page may be pre-charged before calling
2410 * add_to_page_cache(). (See shmem.c) check it here and avoid to call
2411 * charge twice. (It works but has to pay a bit larger cost.)
2412 * And when the page is SwapCache, it should take swap information
2413 * into account. This is under lock_page() now.
2415 if (!(gfp_mask & __GFP_WAIT)) {
2416 struct page_cgroup *pc;
2418 pc = lookup_page_cgroup(page);
2421 lock_page_cgroup(pc);
2422 if (PageCgroupUsed(pc)) {
2423 unlock_page_cgroup(pc);
2426 unlock_page_cgroup(pc);
2432 if (page_is_file_cache(page))
2433 return mem_cgroup_charge_common(page, mm, gfp_mask,
2434 MEM_CGROUP_CHARGE_TYPE_CACHE);
2437 if (PageSwapCache(page)) {
2438 struct mem_cgroup *mem;
2440 ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &mem);
2442 __mem_cgroup_commit_charge_swapin(page, mem,
2443 MEM_CGROUP_CHARGE_TYPE_SHMEM);
2445 ret = mem_cgroup_charge_common(page, mm, gfp_mask,
2446 MEM_CGROUP_CHARGE_TYPE_SHMEM);
2452 * While swap-in, try_charge -> commit or cancel, the page is locked.
2453 * And when try_charge() successfully returns, one refcnt to memcg without
2454 * struct page_cgroup is acquired. This refcnt will be consumed by
2455 * "commit()" or removed by "cancel()"
2457 int mem_cgroup_try_charge_swapin(struct mm_struct *mm,
2459 gfp_t mask, struct mem_cgroup **ptr)
2461 struct mem_cgroup *mem;
2466 if (mem_cgroup_disabled())
2469 if (!do_swap_account)
2472 * A racing thread's fault, or swapoff, may have already updated
2473 * the pte, and even removed page from swap cache: in those cases
2474 * do_swap_page()'s pte_same() test will fail; but there's also a
2475 * KSM case which does need to charge the page.
2477 if (!PageSwapCache(page))
2479 mem = try_get_mem_cgroup_from_page(page);
2483 ret = __mem_cgroup_try_charge(NULL, mask, ptr, true, PAGE_SIZE);
2489 return __mem_cgroup_try_charge(mm, mask, ptr, true, PAGE_SIZE);
2493 __mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr,
2494 enum charge_type ctype)
2496 struct page_cgroup *pc;
2498 if (mem_cgroup_disabled())
2502 cgroup_exclude_rmdir(&ptr->css);
2503 pc = lookup_page_cgroup(page);
2504 mem_cgroup_lru_del_before_commit_swapcache(page);
2505 __mem_cgroup_commit_charge(ptr, page, pc, ctype, PAGE_SIZE);
2506 mem_cgroup_lru_add_after_commit_swapcache(page);
2508 * Now swap is on-memory. This means this page may be
2509 * counted both as mem and swap....double count.
2510 * Fix it by uncharging from memsw. Basically, this SwapCache is stable
2511 * under lock_page(). But in do_swap_page()::memory.c, reuse_swap_page()
2512 * may call delete_from_swap_cache() before reach here.
2514 if (do_swap_account && PageSwapCache(page)) {
2515 swp_entry_t ent = {.val = page_private(page)};
2517 struct mem_cgroup *memcg;
2519 id = swap_cgroup_record(ent, 0);
2521 memcg = mem_cgroup_lookup(id);
2524 * This recorded memcg can be obsolete one. So, avoid
2525 * calling css_tryget
2527 if (!mem_cgroup_is_root(memcg))
2528 res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
2529 mem_cgroup_swap_statistics(memcg, false);
2530 mem_cgroup_put(memcg);
2535 * At swapin, we may charge account against cgroup which has no tasks.
2536 * So, rmdir()->pre_destroy() can be called while we do this charge.
2537 * In that case, we need to call pre_destroy() again. check it here.
2539 cgroup_release_and_wakeup_rmdir(&ptr->css);
2542 void mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr)
2544 __mem_cgroup_commit_charge_swapin(page, ptr,
2545 MEM_CGROUP_CHARGE_TYPE_MAPPED);
2548 void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *mem)
2550 if (mem_cgroup_disabled())
2554 mem_cgroup_cancel_charge(mem, PAGE_SIZE);
2558 __do_uncharge(struct mem_cgroup *mem, const enum charge_type ctype,
2561 struct memcg_batch_info *batch = NULL;
2562 bool uncharge_memsw = true;
2563 /* If swapout, usage of swap doesn't decrease */
2564 if (!do_swap_account || ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT)
2565 uncharge_memsw = false;
2567 batch = ¤t->memcg_batch;
2569 * In usual, we do css_get() when we remember memcg pointer.
2570 * But in this case, we keep res->usage until end of a series of
2571 * uncharges. Then, it's ok to ignore memcg's refcnt.
2576 * do_batch > 0 when unmapping pages or inode invalidate/truncate.
2577 * In those cases, all pages freed continously can be expected to be in
2578 * the same cgroup and we have chance to coalesce uncharges.
2579 * But we do uncharge one by one if this is killed by OOM(TIF_MEMDIE)
2580 * because we want to do uncharge as soon as possible.
2583 if (!batch->do_batch || test_thread_flag(TIF_MEMDIE))
2584 goto direct_uncharge;
2586 if (page_size != PAGE_SIZE)
2587 goto direct_uncharge;
2590 * In typical case, batch->memcg == mem. This means we can
2591 * merge a series of uncharges to an uncharge of res_counter.
2592 * If not, we uncharge res_counter ony by one.
2594 if (batch->memcg != mem)
2595 goto direct_uncharge;
2596 /* remember freed charge and uncharge it later */
2597 batch->bytes += PAGE_SIZE;
2599 batch->memsw_bytes += PAGE_SIZE;
2602 res_counter_uncharge(&mem->res, page_size);
2604 res_counter_uncharge(&mem->memsw, page_size);
2605 if (unlikely(batch->memcg != mem))
2606 memcg_oom_recover(mem);
2611 * uncharge if !page_mapped(page)
2613 static struct mem_cgroup *
2614 __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
2617 struct page_cgroup *pc;
2618 struct mem_cgroup *mem = NULL;
2619 int page_size = PAGE_SIZE;
2621 if (mem_cgroup_disabled())
2624 if (PageSwapCache(page))
2627 if (PageTransHuge(page)) {
2628 page_size <<= compound_order(page);
2629 VM_BUG_ON(!PageTransHuge(page));
2632 count = page_size >> PAGE_SHIFT;
2634 * Check if our page_cgroup is valid
2636 pc = lookup_page_cgroup(page);
2637 if (unlikely(!pc || !PageCgroupUsed(pc)))
2640 lock_page_cgroup(pc);
2642 mem = pc->mem_cgroup;
2644 if (!PageCgroupUsed(pc))
2648 case MEM_CGROUP_CHARGE_TYPE_MAPPED:
2649 case MEM_CGROUP_CHARGE_TYPE_DROP:
2650 /* See mem_cgroup_prepare_migration() */
2651 if (page_mapped(page) || PageCgroupMigration(pc))
2654 case MEM_CGROUP_CHARGE_TYPE_SWAPOUT:
2655 if (!PageAnon(page)) { /* Shared memory */
2656 if (page->mapping && !page_is_file_cache(page))
2658 } else if (page_mapped(page)) /* Anon */
2665 mem_cgroup_charge_statistics(mem, PageCgroupCache(pc), -count);
2667 ClearPageCgroupUsed(pc);
2669 * pc->mem_cgroup is not cleared here. It will be accessed when it's
2670 * freed from LRU. This is safe because uncharged page is expected not
2671 * to be reused (freed soon). Exception is SwapCache, it's handled by
2672 * special functions.
2675 unlock_page_cgroup(pc);
2677 * even after unlock, we have mem->res.usage here and this memcg
2678 * will never be freed.
2680 memcg_check_events(mem, page);
2681 if (do_swap_account && ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT) {
2682 mem_cgroup_swap_statistics(mem, true);
2683 mem_cgroup_get(mem);
2685 if (!mem_cgroup_is_root(mem))
2686 __do_uncharge(mem, ctype, page_size);
2691 unlock_page_cgroup(pc);
2695 void mem_cgroup_uncharge_page(struct page *page)
2698 if (page_mapped(page))
2700 if (page->mapping && !PageAnon(page))
2702 __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_MAPPED);
2705 void mem_cgroup_uncharge_cache_page(struct page *page)
2707 VM_BUG_ON(page_mapped(page));
2708 VM_BUG_ON(page->mapping);
2709 __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE);
2713 * Batch_start/batch_end is called in unmap_page_range/invlidate/trucate.
2714 * In that cases, pages are freed continuously and we can expect pages
2715 * are in the same memcg. All these calls itself limits the number of
2716 * pages freed at once, then uncharge_start/end() is called properly.
2717 * This may be called prural(2) times in a context,
2720 void mem_cgroup_uncharge_start(void)
2722 current->memcg_batch.do_batch++;
2723 /* We can do nest. */
2724 if (current->memcg_batch.do_batch == 1) {
2725 current->memcg_batch.memcg = NULL;
2726 current->memcg_batch.bytes = 0;
2727 current->memcg_batch.memsw_bytes = 0;
2731 void mem_cgroup_uncharge_end(void)
2733 struct memcg_batch_info *batch = ¤t->memcg_batch;
2735 if (!batch->do_batch)
2739 if (batch->do_batch) /* If stacked, do nothing. */
2745 * This "batch->memcg" is valid without any css_get/put etc...
2746 * bacause we hide charges behind us.
2749 res_counter_uncharge(&batch->memcg->res, batch->bytes);
2750 if (batch->memsw_bytes)
2751 res_counter_uncharge(&batch->memcg->memsw, batch->memsw_bytes);
2752 memcg_oom_recover(batch->memcg);
2753 /* forget this pointer (for sanity check) */
2754 batch->memcg = NULL;
2759 * called after __delete_from_swap_cache() and drop "page" account.
2760 * memcg information is recorded to swap_cgroup of "ent"
2763 mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout)
2765 struct mem_cgroup *memcg;
2766 int ctype = MEM_CGROUP_CHARGE_TYPE_SWAPOUT;
2768 if (!swapout) /* this was a swap cache but the swap is unused ! */
2769 ctype = MEM_CGROUP_CHARGE_TYPE_DROP;
2771 memcg = __mem_cgroup_uncharge_common(page, ctype);
2774 * record memcg information, if swapout && memcg != NULL,
2775 * mem_cgroup_get() was called in uncharge().
2777 if (do_swap_account && swapout && memcg)
2778 swap_cgroup_record(ent, css_id(&memcg->css));
2782 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
2784 * called from swap_entry_free(). remove record in swap_cgroup and
2785 * uncharge "memsw" account.
2787 void mem_cgroup_uncharge_swap(swp_entry_t ent)
2789 struct mem_cgroup *memcg;
2792 if (!do_swap_account)
2795 id = swap_cgroup_record(ent, 0);
2797 memcg = mem_cgroup_lookup(id);
2800 * We uncharge this because swap is freed.
2801 * This memcg can be obsolete one. We avoid calling css_tryget
2803 if (!mem_cgroup_is_root(memcg))
2804 res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
2805 mem_cgroup_swap_statistics(memcg, false);
2806 mem_cgroup_put(memcg);
2812 * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record.
2813 * @entry: swap entry to be moved
2814 * @from: mem_cgroup which the entry is moved from
2815 * @to: mem_cgroup which the entry is moved to
2816 * @need_fixup: whether we should fixup res_counters and refcounts.
2818 * It succeeds only when the swap_cgroup's record for this entry is the same
2819 * as the mem_cgroup's id of @from.
2821 * Returns 0 on success, -EINVAL on failure.
2823 * The caller must have charged to @to, IOW, called res_counter_charge() about
2824 * both res and memsw, and called css_get().
2826 static int mem_cgroup_move_swap_account(swp_entry_t entry,
2827 struct mem_cgroup *from, struct mem_cgroup *to, bool need_fixup)
2829 unsigned short old_id, new_id;
2831 old_id = css_id(&from->css);
2832 new_id = css_id(&to->css);
2834 if (swap_cgroup_cmpxchg(entry, old_id, new_id) == old_id) {
2835 mem_cgroup_swap_statistics(from, false);
2836 mem_cgroup_swap_statistics(to, true);
2838 * This function is only called from task migration context now.
2839 * It postpones res_counter and refcount handling till the end
2840 * of task migration(mem_cgroup_clear_mc()) for performance
2841 * improvement. But we cannot postpone mem_cgroup_get(to)
2842 * because if the process that has been moved to @to does
2843 * swap-in, the refcount of @to might be decreased to 0.
2847 if (!mem_cgroup_is_root(from))
2848 res_counter_uncharge(&from->memsw, PAGE_SIZE);
2849 mem_cgroup_put(from);
2851 * we charged both to->res and to->memsw, so we should
2854 if (!mem_cgroup_is_root(to))
2855 res_counter_uncharge(&to->res, PAGE_SIZE);
2862 static inline int mem_cgroup_move_swap_account(swp_entry_t entry,
2863 struct mem_cgroup *from, struct mem_cgroup *to, bool need_fixup)
2870 * Before starting migration, account PAGE_SIZE to mem_cgroup that the old
2873 int mem_cgroup_prepare_migration(struct page *page,
2874 struct page *newpage, struct mem_cgroup **ptr, gfp_t gfp_mask)
2876 struct page_cgroup *pc;
2877 struct mem_cgroup *mem = NULL;
2878 enum charge_type ctype;
2883 VM_BUG_ON(PageTransHuge(page));
2884 if (mem_cgroup_disabled())
2887 pc = lookup_page_cgroup(page);
2888 lock_page_cgroup(pc);
2889 if (PageCgroupUsed(pc)) {
2890 mem = pc->mem_cgroup;
2893 * At migrating an anonymous page, its mapcount goes down
2894 * to 0 and uncharge() will be called. But, even if it's fully
2895 * unmapped, migration may fail and this page has to be
2896 * charged again. We set MIGRATION flag here and delay uncharge
2897 * until end_migration() is called
2899 * Corner Case Thinking
2901 * When the old page was mapped as Anon and it's unmap-and-freed
2902 * while migration was ongoing.
2903 * If unmap finds the old page, uncharge() of it will be delayed
2904 * until end_migration(). If unmap finds a new page, it's
2905 * uncharged when it make mapcount to be 1->0. If unmap code
2906 * finds swap_migration_entry, the new page will not be mapped
2907 * and end_migration() will find it(mapcount==0).
2910 * When the old page was mapped but migraion fails, the kernel
2911 * remaps it. A charge for it is kept by MIGRATION flag even
2912 * if mapcount goes down to 0. We can do remap successfully
2913 * without charging it again.
2916 * The "old" page is under lock_page() until the end of
2917 * migration, so, the old page itself will not be swapped-out.
2918 * If the new page is swapped out before end_migraton, our
2919 * hook to usual swap-out path will catch the event.
2922 SetPageCgroupMigration(pc);
2924 unlock_page_cgroup(pc);
2926 * If the page is not charged at this point,
2933 ret = __mem_cgroup_try_charge(NULL, gfp_mask, ptr, false, PAGE_SIZE);
2934 css_put(&mem->css);/* drop extra refcnt */
2935 if (ret || *ptr == NULL) {
2936 if (PageAnon(page)) {
2937 lock_page_cgroup(pc);
2938 ClearPageCgroupMigration(pc);
2939 unlock_page_cgroup(pc);
2941 * The old page may be fully unmapped while we kept it.
2943 mem_cgroup_uncharge_page(page);
2948 * We charge new page before it's used/mapped. So, even if unlock_page()
2949 * is called before end_migration, we can catch all events on this new
2950 * page. In the case new page is migrated but not remapped, new page's
2951 * mapcount will be finally 0 and we call uncharge in end_migration().
2953 pc = lookup_page_cgroup(newpage);
2955 ctype = MEM_CGROUP_CHARGE_TYPE_MAPPED;
2956 else if (page_is_file_cache(page))
2957 ctype = MEM_CGROUP_CHARGE_TYPE_CACHE;
2959 ctype = MEM_CGROUP_CHARGE_TYPE_SHMEM;
2960 __mem_cgroup_commit_charge(mem, page, pc, ctype, PAGE_SIZE);
2964 /* remove redundant charge if migration failed*/
2965 void mem_cgroup_end_migration(struct mem_cgroup *mem,
2966 struct page *oldpage, struct page *newpage, bool migration_ok)
2968 struct page *used, *unused;
2969 struct page_cgroup *pc;
2973 /* blocks rmdir() */
2974 cgroup_exclude_rmdir(&mem->css);
2975 if (!migration_ok) {
2983 * We disallowed uncharge of pages under migration because mapcount
2984 * of the page goes down to zero, temporarly.
2985 * Clear the flag and check the page should be charged.
2987 pc = lookup_page_cgroup(oldpage);
2988 lock_page_cgroup(pc);
2989 ClearPageCgroupMigration(pc);
2990 unlock_page_cgroup(pc);
2992 __mem_cgroup_uncharge_common(unused, MEM_CGROUP_CHARGE_TYPE_FORCE);
2995 * If a page is a file cache, radix-tree replacement is very atomic
2996 * and we can skip this check. When it was an Anon page, its mapcount
2997 * goes down to 0. But because we added MIGRATION flage, it's not
2998 * uncharged yet. There are several case but page->mapcount check
2999 * and USED bit check in mem_cgroup_uncharge_page() will do enough
3000 * check. (see prepare_charge() also)
3003 mem_cgroup_uncharge_page(used);
3005 * At migration, we may charge account against cgroup which has no
3007 * So, rmdir()->pre_destroy() can be called while we do this charge.
3008 * In that case, we need to call pre_destroy() again. check it here.
3010 cgroup_release_and_wakeup_rmdir(&mem->css);
3014 * A call to try to shrink memory usage on charge failure at shmem's swapin.
3015 * Calling hierarchical_reclaim is not enough because we should update
3016 * last_oom_jiffies to prevent pagefault_out_of_memory from invoking global OOM.
3017 * Moreover considering hierarchy, we should reclaim from the mem_over_limit,
3018 * not from the memcg which this page would be charged to.
3019 * try_charge_swapin does all of these works properly.
3021 int mem_cgroup_shmem_charge_fallback(struct page *page,
3022 struct mm_struct *mm,
3025 struct mem_cgroup *mem;
3028 if (mem_cgroup_disabled())
3031 ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &mem);
3033 mem_cgroup_cancel_charge_swapin(mem); /* it does !mem check */
3038 #ifdef CONFIG_DEBUG_VM
3039 static struct page_cgroup *lookup_page_cgroup_used(struct page *page)
3041 struct page_cgroup *pc;
3043 pc = lookup_page_cgroup(page);
3044 if (likely(pc) && PageCgroupUsed(pc))
3049 bool mem_cgroup_bad_page_check(struct page *page)
3051 if (mem_cgroup_disabled())
3054 return lookup_page_cgroup_used(page) != NULL;
3057 void mem_cgroup_print_bad_page(struct page *page)
3059 struct page_cgroup *pc;
3061 pc = lookup_page_cgroup_used(page);
3066 printk(KERN_ALERT "pc:%p pc->flags:%lx pc->mem_cgroup:%p",
3067 pc, pc->flags, pc->mem_cgroup);
3069 path = kmalloc(PATH_MAX, GFP_KERNEL);
3072 ret = cgroup_path(pc->mem_cgroup->css.cgroup,
3077 printk(KERN_CONT "(%s)\n",
3078 (ret < 0) ? "cannot get the path" : path);
3084 static DEFINE_MUTEX(set_limit_mutex);
3086 static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
3087 unsigned long long val)
3090 u64 memswlimit, memlimit;
3092 int children = mem_cgroup_count_children(memcg);
3093 u64 curusage, oldusage;
3097 * For keeping hierarchical_reclaim simple, how long we should retry
3098 * is depends on callers. We set our retry-count to be function
3099 * of # of children which we should visit in this loop.
3101 retry_count = MEM_CGROUP_RECLAIM_RETRIES * children;
3103 oldusage = res_counter_read_u64(&memcg->res, RES_USAGE);
3106 while (retry_count) {
3107 if (signal_pending(current)) {
3112 * Rather than hide all in some function, I do this in
3113 * open coded manner. You see what this really does.
3114 * We have to guarantee mem->res.limit < mem->memsw.limit.
3116 mutex_lock(&set_limit_mutex);
3117 memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
3118 if (memswlimit < val) {
3120 mutex_unlock(&set_limit_mutex);
3124 memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT);
3128 ret = res_counter_set_limit(&memcg->res, val);
3130 if (memswlimit == val)
3131 memcg->memsw_is_minimum = true;
3133 memcg->memsw_is_minimum = false;
3135 mutex_unlock(&set_limit_mutex);
3140 mem_cgroup_hierarchical_reclaim(memcg, NULL, GFP_KERNEL,
3141 MEM_CGROUP_RECLAIM_SHRINK);
3142 curusage = res_counter_read_u64(&memcg->res, RES_USAGE);
3143 /* Usage is reduced ? */
3144 if (curusage >= oldusage)
3147 oldusage = curusage;
3149 if (!ret && enlarge)
3150 memcg_oom_recover(memcg);
3155 static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
3156 unsigned long long val)
3159 u64 memlimit, memswlimit, oldusage, curusage;
3160 int children = mem_cgroup_count_children(memcg);
3164 /* see mem_cgroup_resize_res_limit */
3165 retry_count = children * MEM_CGROUP_RECLAIM_RETRIES;
3166 oldusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
3167 while (retry_count) {
3168 if (signal_pending(current)) {
3173 * Rather than hide all in some function, I do this in
3174 * open coded manner. You see what this really does.
3175 * We have to guarantee mem->res.limit < mem->memsw.limit.
3177 mutex_lock(&set_limit_mutex);
3178 memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT);
3179 if (memlimit > val) {
3181 mutex_unlock(&set_limit_mutex);
3184 memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
3185 if (memswlimit < val)
3187 ret = res_counter_set_limit(&memcg->memsw, val);
3189 if (memlimit == val)
3190 memcg->memsw_is_minimum = true;
3192 memcg->memsw_is_minimum = false;
3194 mutex_unlock(&set_limit_mutex);
3199 mem_cgroup_hierarchical_reclaim(memcg, NULL, GFP_KERNEL,
3200 MEM_CGROUP_RECLAIM_NOSWAP |
3201 MEM_CGROUP_RECLAIM_SHRINK);
3202 curusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
3203 /* Usage is reduced ? */
3204 if (curusage >= oldusage)
3207 oldusage = curusage;
3209 if (!ret && enlarge)
3210 memcg_oom_recover(memcg);
3214 unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
3217 unsigned long nr_reclaimed = 0;
3218 struct mem_cgroup_per_zone *mz, *next_mz = NULL;
3219 unsigned long reclaimed;
3221 struct mem_cgroup_tree_per_zone *mctz;
3222 unsigned long long excess;
3227 mctz = soft_limit_tree_node_zone(zone_to_nid(zone), zone_idx(zone));
3229 * This loop can run a while, specially if mem_cgroup's continuously
3230 * keep exceeding their soft limit and putting the system under
3237 mz = mem_cgroup_largest_soft_limit_node(mctz);
3241 reclaimed = mem_cgroup_hierarchical_reclaim(mz->mem, zone,
3243 MEM_CGROUP_RECLAIM_SOFT);
3244 nr_reclaimed += reclaimed;
3245 spin_lock(&mctz->lock);
3248 * If we failed to reclaim anything from this memory cgroup
3249 * it is time to move on to the next cgroup
3255 * Loop until we find yet another one.
3257 * By the time we get the soft_limit lock
3258 * again, someone might have aded the
3259 * group back on the RB tree. Iterate to
3260 * make sure we get a different mem.
3261 * mem_cgroup_largest_soft_limit_node returns
3262 * NULL if no other cgroup is present on
3266 __mem_cgroup_largest_soft_limit_node(mctz);
3267 if (next_mz == mz) {
3268 css_put(&next_mz->mem->css);
3270 } else /* next_mz == NULL or other memcg */
3274 __mem_cgroup_remove_exceeded(mz->mem, mz, mctz);
3275 excess = res_counter_soft_limit_excess(&mz->mem->res);
3277 * One school of thought says that we should not add
3278 * back the node to the tree if reclaim returns 0.
3279 * But our reclaim could return 0, simply because due
3280 * to priority we are exposing a smaller subset of
3281 * memory to reclaim from. Consider this as a longer
3284 /* If excess == 0, no tree ops */
3285 __mem_cgroup_insert_exceeded(mz->mem, mz, mctz, excess);
3286 spin_unlock(&mctz->lock);
3287 css_put(&mz->mem->css);
3290 * Could not reclaim anything and there are no more
3291 * mem cgroups to try or we seem to be looping without
3292 * reclaiming anything.
3294 if (!nr_reclaimed &&
3296 loop > MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS))
3298 } while (!nr_reclaimed);
3300 css_put(&next_mz->mem->css);
3301 return nr_reclaimed;
3305 * This routine traverse page_cgroup in given list and drop them all.
3306 * *And* this routine doesn't reclaim page itself, just removes page_cgroup.
3308 static int mem_cgroup_force_empty_list(struct mem_cgroup *mem,
3309 int node, int zid, enum lru_list lru)
3312 struct mem_cgroup_per_zone *mz;
3313 struct page_cgroup *pc, *busy;
3314 unsigned long flags, loop;
3315 struct list_head *list;
3318 zone = &NODE_DATA(node)->node_zones[zid];
3319 mz = mem_cgroup_zoneinfo(mem, node, zid);
3320 list = &mz->lists[lru];
3322 loop = MEM_CGROUP_ZSTAT(mz, lru);
3323 /* give some margin against EBUSY etc...*/
3330 spin_lock_irqsave(&zone->lru_lock, flags);
3331 if (list_empty(list)) {
3332 spin_unlock_irqrestore(&zone->lru_lock, flags);
3335 pc = list_entry(list->prev, struct page_cgroup, lru);
3337 list_move(&pc->lru, list);
3339 spin_unlock_irqrestore(&zone->lru_lock, flags);
3342 spin_unlock_irqrestore(&zone->lru_lock, flags);
3344 page = lookup_cgroup_page(pc);
3346 ret = mem_cgroup_move_parent(page, pc, mem, GFP_KERNEL);
3350 if (ret == -EBUSY || ret == -EINVAL) {
3351 /* found lock contention or "pc" is obsolete. */
3358 if (!ret && !list_empty(list))
3364 * make mem_cgroup's charge to be 0 if there is no task.
3365 * This enables deleting this mem_cgroup.
3367 static int mem_cgroup_force_empty(struct mem_cgroup *mem, bool free_all)
3370 int node, zid, shrink;
3371 int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
3372 struct cgroup *cgrp = mem->css.cgroup;
3377 /* should free all ? */
3383 if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children))
3386 if (signal_pending(current))
3388 /* This is for making all *used* pages to be on LRU. */
3389 lru_add_drain_all();
3390 drain_all_stock_sync();
3392 mem_cgroup_start_move(mem);
3393 for_each_node_state(node, N_HIGH_MEMORY) {
3394 for (zid = 0; !ret && zid < MAX_NR_ZONES; zid++) {
3397 ret = mem_cgroup_force_empty_list(mem,
3406 mem_cgroup_end_move(mem);
3407 memcg_oom_recover(mem);
3408 /* it seems parent cgroup doesn't have enough mem */
3412 /* "ret" should also be checked to ensure all lists are empty. */
3413 } while (mem->res.usage > 0 || ret);
3419 /* returns EBUSY if there is a task or if we come here twice. */
3420 if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children) || shrink) {
3424 /* we call try-to-free pages for make this cgroup empty */
3425 lru_add_drain_all();
3426 /* try to free all pages in this cgroup */
3428 while (nr_retries && mem->res.usage > 0) {
3431 if (signal_pending(current)) {
3435 progress = try_to_free_mem_cgroup_pages(mem, GFP_KERNEL,
3436 false, get_swappiness(mem));
3439 /* maybe some writeback is necessary */
3440 congestion_wait(BLK_RW_ASYNC, HZ/10);
3445 /* try move_account...there may be some *locked* pages. */
3449 int mem_cgroup_force_empty_write(struct cgroup *cont, unsigned int event)
3451 return mem_cgroup_force_empty(mem_cgroup_from_cont(cont), true);
3455 static u64 mem_cgroup_hierarchy_read(struct cgroup *cont, struct cftype *cft)
3457 return mem_cgroup_from_cont(cont)->use_hierarchy;
3460 static int mem_cgroup_hierarchy_write(struct cgroup *cont, struct cftype *cft,
3464 struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
3465 struct cgroup *parent = cont->parent;
3466 struct mem_cgroup *parent_mem = NULL;
3469 parent_mem = mem_cgroup_from_cont(parent);
3473 * If parent's use_hierarchy is set, we can't make any modifications
3474 * in the child subtrees. If it is unset, then the change can
3475 * occur, provided the current cgroup has no children.
3477 * For the root cgroup, parent_mem is NULL, we allow value to be
3478 * set if there are no children.
3480 if ((!parent_mem || !parent_mem->use_hierarchy) &&
3481 (val == 1 || val == 0)) {
3482 if (list_empty(&cont->children))
3483 mem->use_hierarchy = val;
3494 static u64 mem_cgroup_get_recursive_idx_stat(struct mem_cgroup *mem,
3495 enum mem_cgroup_stat_index idx)
3497 struct mem_cgroup *iter;
3500 /* each per cpu's value can be minus.Then, use s64 */
3501 for_each_mem_cgroup_tree(iter, mem)
3502 val += mem_cgroup_read_stat(iter, idx);
3504 if (val < 0) /* race ? */
3509 static inline u64 mem_cgroup_usage(struct mem_cgroup *mem, bool swap)
3513 if (!mem_cgroup_is_root(mem)) {
3515 return res_counter_read_u64(&mem->res, RES_USAGE);
3517 return res_counter_read_u64(&mem->memsw, RES_USAGE);
3520 val = mem_cgroup_get_recursive_idx_stat(mem, MEM_CGROUP_STAT_CACHE);
3521 val += mem_cgroup_get_recursive_idx_stat(mem, MEM_CGROUP_STAT_RSS);
3524 val += mem_cgroup_get_recursive_idx_stat(mem,
3525 MEM_CGROUP_STAT_SWAPOUT);
3527 return val << PAGE_SHIFT;
3530 static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft)
3532 struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
3536 type = MEMFILE_TYPE(cft->private);
3537 name = MEMFILE_ATTR(cft->private);
3540 if (name == RES_USAGE)
3541 val = mem_cgroup_usage(mem, false);
3543 val = res_counter_read_u64(&mem->res, name);
3546 if (name == RES_USAGE)
3547 val = mem_cgroup_usage(mem, true);
3549 val = res_counter_read_u64(&mem->memsw, name);
3558 * The user of this function is...
3561 static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
3564 struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
3566 unsigned long long val;
3569 type = MEMFILE_TYPE(cft->private);
3570 name = MEMFILE_ATTR(cft->private);
3573 if (mem_cgroup_is_root(memcg)) { /* Can't set limit on root */
3577 /* This function does all necessary parse...reuse it */
3578 ret = res_counter_memparse_write_strategy(buffer, &val);
3582 ret = mem_cgroup_resize_limit(memcg, val);
3584 ret = mem_cgroup_resize_memsw_limit(memcg, val);
3586 case RES_SOFT_LIMIT:
3587 ret = res_counter_memparse_write_strategy(buffer, &val);
3591 * For memsw, soft limits are hard to implement in terms
3592 * of semantics, for now, we support soft limits for
3593 * control without swap
3596 ret = res_counter_set_soft_limit(&memcg->res, val);
3601 ret = -EINVAL; /* should be BUG() ? */
3607 static void memcg_get_hierarchical_limit(struct mem_cgroup *memcg,
3608 unsigned long long *mem_limit, unsigned long long *memsw_limit)
3610 struct cgroup *cgroup;
3611 unsigned long long min_limit, min_memsw_limit, tmp;
3613 min_limit = res_counter_read_u64(&memcg->res, RES_LIMIT);
3614 min_memsw_limit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
3615 cgroup = memcg->css.cgroup;
3616 if (!memcg->use_hierarchy)
3619 while (cgroup->parent) {
3620 cgroup = cgroup->parent;
3621 memcg = mem_cgroup_from_cont(cgroup);
3622 if (!memcg->use_hierarchy)
3624 tmp = res_counter_read_u64(&memcg->res, RES_LIMIT);
3625 min_limit = min(min_limit, tmp);
3626 tmp = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
3627 min_memsw_limit = min(min_memsw_limit, tmp);
3630 *mem_limit = min_limit;
3631 *memsw_limit = min_memsw_limit;
3635 static int mem_cgroup_reset(struct cgroup *cont, unsigned int event)
3637 struct mem_cgroup *mem;
3640 mem = mem_cgroup_from_cont(cont);
3641 type = MEMFILE_TYPE(event);
3642 name = MEMFILE_ATTR(event);
3646 res_counter_reset_max(&mem->res);
3648 res_counter_reset_max(&mem->memsw);
3652 res_counter_reset_failcnt(&mem->res);
3654 res_counter_reset_failcnt(&mem->memsw);
3661 static u64 mem_cgroup_move_charge_read(struct cgroup *cgrp,
3664 return mem_cgroup_from_cont(cgrp)->move_charge_at_immigrate;
3668 static int mem_cgroup_move_charge_write(struct cgroup *cgrp,
3669 struct cftype *cft, u64 val)
3671 struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp);
3673 if (val >= (1 << NR_MOVE_TYPE))
3676 * We check this value several times in both in can_attach() and
3677 * attach(), so we need cgroup lock to prevent this value from being
3681 mem->move_charge_at_immigrate = val;
3687 static int mem_cgroup_move_charge_write(struct cgroup *cgrp,
3688 struct cftype *cft, u64 val)
3695 /* For read statistics */
3711 struct mcs_total_stat {
3712 s64 stat[NR_MCS_STAT];
3718 } memcg_stat_strings[NR_MCS_STAT] = {
3719 {"cache", "total_cache"},
3720 {"rss", "total_rss"},
3721 {"mapped_file", "total_mapped_file"},
3722 {"pgpgin", "total_pgpgin"},
3723 {"pgpgout", "total_pgpgout"},
3724 {"swap", "total_swap"},
3725 {"inactive_anon", "total_inactive_anon"},
3726 {"active_anon", "total_active_anon"},
3727 {"inactive_file", "total_inactive_file"},
3728 {"active_file", "total_active_file"},
3729 {"unevictable", "total_unevictable"}
3734 mem_cgroup_get_local_stat(struct mem_cgroup *mem, struct mcs_total_stat *s)
3739 val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_CACHE);
3740 s->stat[MCS_CACHE] += val * PAGE_SIZE;
3741 val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_RSS);
3742 s->stat[MCS_RSS] += val * PAGE_SIZE;
3743 val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_FILE_MAPPED);
3744 s->stat[MCS_FILE_MAPPED] += val * PAGE_SIZE;
3745 val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_PGPGIN_COUNT);
3746 s->stat[MCS_PGPGIN] += val;
3747 val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_PGPGOUT_COUNT);
3748 s->stat[MCS_PGPGOUT] += val;
3749 if (do_swap_account) {
3750 val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_SWAPOUT);
3751 s->stat[MCS_SWAP] += val * PAGE_SIZE;
3755 val = mem_cgroup_get_local_zonestat(mem, LRU_INACTIVE_ANON);
3756 s->stat[MCS_INACTIVE_ANON] += val * PAGE_SIZE;
3757 val = mem_cgroup_get_local_zonestat(mem, LRU_ACTIVE_ANON);
3758 s->stat[MCS_ACTIVE_ANON] += val * PAGE_SIZE;
3759 val = mem_cgroup_get_local_zonestat(mem, LRU_INACTIVE_FILE);
3760 s->stat[MCS_INACTIVE_FILE] += val * PAGE_SIZE;
3761 val = mem_cgroup_get_local_zonestat(mem, LRU_ACTIVE_FILE);
3762 s->stat[MCS_ACTIVE_FILE] += val * PAGE_SIZE;
3763 val = mem_cgroup_get_local_zonestat(mem, LRU_UNEVICTABLE);
3764 s->stat[MCS_UNEVICTABLE] += val * PAGE_SIZE;
3768 mem_cgroup_get_total_stat(struct mem_cgroup *mem, struct mcs_total_stat *s)
3770 struct mem_cgroup *iter;
3772 for_each_mem_cgroup_tree(iter, mem)
3773 mem_cgroup_get_local_stat(iter, s);
3776 static int mem_control_stat_show(struct cgroup *cont, struct cftype *cft,
3777 struct cgroup_map_cb *cb)
3779 struct mem_cgroup *mem_cont = mem_cgroup_from_cont(cont);
3780 struct mcs_total_stat mystat;
3783 memset(&mystat, 0, sizeof(mystat));
3784 mem_cgroup_get_local_stat(mem_cont, &mystat);
3786 for (i = 0; i < NR_MCS_STAT; i++) {
3787 if (i == MCS_SWAP && !do_swap_account)
3789 cb->fill(cb, memcg_stat_strings[i].local_name, mystat.stat[i]);
3792 /* Hierarchical information */
3794 unsigned long long limit, memsw_limit;
3795 memcg_get_hierarchical_limit(mem_cont, &limit, &memsw_limit);
3796 cb->fill(cb, "hierarchical_memory_limit", limit);
3797 if (do_swap_account)
3798 cb->fill(cb, "hierarchical_memsw_limit", memsw_limit);
3801 memset(&mystat, 0, sizeof(mystat));
3802 mem_cgroup_get_total_stat(mem_cont, &mystat);
3803 for (i = 0; i < NR_MCS_STAT; i++) {
3804 if (i == MCS_SWAP && !do_swap_account)
3806 cb->fill(cb, memcg_stat_strings[i].total_name, mystat.stat[i]);
3809 #ifdef CONFIG_DEBUG_VM
3810 cb->fill(cb, "inactive_ratio", calc_inactive_ratio(mem_cont, NULL));
3814 struct mem_cgroup_per_zone *mz;
3815 unsigned long recent_rotated[2] = {0, 0};
3816 unsigned long recent_scanned[2] = {0, 0};
3818 for_each_online_node(nid)
3819 for (zid = 0; zid < MAX_NR_ZONES; zid++) {
3820 mz = mem_cgroup_zoneinfo(mem_cont, nid, zid);
3822 recent_rotated[0] +=
3823 mz->reclaim_stat.recent_rotated[0];
3824 recent_rotated[1] +=
3825 mz->reclaim_stat.recent_rotated[1];
3826 recent_scanned[0] +=
3827 mz->reclaim_stat.recent_scanned[0];
3828 recent_scanned[1] +=
3829 mz->reclaim_stat.recent_scanned[1];
3831 cb->fill(cb, "recent_rotated_anon", recent_rotated[0]);
3832 cb->fill(cb, "recent_rotated_file", recent_rotated[1]);
3833 cb->fill(cb, "recent_scanned_anon", recent_scanned[0]);
3834 cb->fill(cb, "recent_scanned_file", recent_scanned[1]);
3841 static u64 mem_cgroup_swappiness_read(struct cgroup *cgrp, struct cftype *cft)
3843 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
3845 return get_swappiness(memcg);
3848 static int mem_cgroup_swappiness_write(struct cgroup *cgrp, struct cftype *cft,
3851 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
3852 struct mem_cgroup *parent;
3857 if (cgrp->parent == NULL)
3860 parent = mem_cgroup_from_cont(cgrp->parent);
3864 /* If under hierarchy, only empty-root can set this value */
3865 if ((parent->use_hierarchy) ||
3866 (memcg->use_hierarchy && !list_empty(&cgrp->children))) {
3871 spin_lock(&memcg->reclaim_param_lock);
3872 memcg->swappiness = val;
3873 spin_unlock(&memcg->reclaim_param_lock);
3880 static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap)
3882 struct mem_cgroup_threshold_ary *t;
3888 t = rcu_dereference(memcg->thresholds.primary);
3890 t = rcu_dereference(memcg->memsw_thresholds.primary);
3895 usage = mem_cgroup_usage(memcg, swap);
3898 * current_threshold points to threshold just below usage.
3899 * If it's not true, a threshold was crossed after last
3900 * call of __mem_cgroup_threshold().
3902 i = t->current_threshold;
3905 * Iterate backward over array of thresholds starting from
3906 * current_threshold and check if a threshold is crossed.
3907 * If none of thresholds below usage is crossed, we read
3908 * only one element of the array here.
3910 for (; i >= 0 && unlikely(t->entries[i].threshold > usage); i--)
3911 eventfd_signal(t->entries[i].eventfd, 1);
3913 /* i = current_threshold + 1 */
3917 * Iterate forward over array of thresholds starting from
3918 * current_threshold+1 and check if a threshold is crossed.
3919 * If none of thresholds above usage is crossed, we read
3920 * only one element of the array here.
3922 for (; i < t->size && unlikely(t->entries[i].threshold <= usage); i++)
3923 eventfd_signal(t->entries[i].eventfd, 1);
3925 /* Update current_threshold */
3926 t->current_threshold = i - 1;
3931 static void mem_cgroup_threshold(struct mem_cgroup *memcg)
3934 __mem_cgroup_threshold(memcg, false);
3935 if (do_swap_account)
3936 __mem_cgroup_threshold(memcg, true);
3938 memcg = parent_mem_cgroup(memcg);
3942 static int compare_thresholds(const void *a, const void *b)
3944 const struct mem_cgroup_threshold *_a = a;
3945 const struct mem_cgroup_threshold *_b = b;
3947 return _a->threshold - _b->threshold;
3950 static int mem_cgroup_oom_notify_cb(struct mem_cgroup *mem)
3952 struct mem_cgroup_eventfd_list *ev;
3954 list_for_each_entry(ev, &mem->oom_notify, list)
3955 eventfd_signal(ev->eventfd, 1);
3959 static void mem_cgroup_oom_notify(struct mem_cgroup *mem)
3961 struct mem_cgroup *iter;
3963 for_each_mem_cgroup_tree(iter, mem)
3964 mem_cgroup_oom_notify_cb(iter);
3967 static int mem_cgroup_usage_register_event(struct cgroup *cgrp,
3968 struct cftype *cft, struct eventfd_ctx *eventfd, const char *args)
3970 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
3971 struct mem_cgroup_thresholds *thresholds;
3972 struct mem_cgroup_threshold_ary *new;
3973 int type = MEMFILE_TYPE(cft->private);
3974 u64 threshold, usage;
3977 ret = res_counter_memparse_write_strategy(args, &threshold);
3981 mutex_lock(&memcg->thresholds_lock);
3984 thresholds = &memcg->thresholds;
3985 else if (type == _MEMSWAP)
3986 thresholds = &memcg->memsw_thresholds;
3990 usage = mem_cgroup_usage(memcg, type == _MEMSWAP);
3992 /* Check if a threshold crossed before adding a new one */
3993 if (thresholds->primary)
3994 __mem_cgroup_threshold(memcg, type == _MEMSWAP);
3996 size = thresholds->primary ? thresholds->primary->size + 1 : 1;
3998 /* Allocate memory for new array of thresholds */
3999 new = kmalloc(sizeof(*new) + size * sizeof(struct mem_cgroup_threshold),
4007 /* Copy thresholds (if any) to new array */
4008 if (thresholds->primary) {
4009 memcpy(new->entries, thresholds->primary->entries, (size - 1) *
4010 sizeof(struct mem_cgroup_threshold));
4013 /* Add new threshold */
4014 new->entries[size - 1].eventfd = eventfd;
4015 new->entries[size - 1].threshold = threshold;
4017 /* Sort thresholds. Registering of new threshold isn't time-critical */
4018 sort(new->entries, size, sizeof(struct mem_cgroup_threshold),
4019 compare_thresholds, NULL);
4021 /* Find current threshold */
4022 new->current_threshold = -1;
4023 for (i = 0; i < size; i++) {
4024 if (new->entries[i].threshold < usage) {
4026 * new->current_threshold will not be used until
4027 * rcu_assign_pointer(), so it's safe to increment
4030 ++new->current_threshold;
4034 /* Free old spare buffer and save old primary buffer as spare */
4035 kfree(thresholds->spare);
4036 thresholds->spare = thresholds->primary;
4038 rcu_assign_pointer(thresholds->primary, new);
4040 /* To be sure that nobody uses thresholds */
4044 mutex_unlock(&memcg->thresholds_lock);
4049 static void mem_cgroup_usage_unregister_event(struct cgroup *cgrp,
4050 struct cftype *cft, struct eventfd_ctx *eventfd)
4052 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
4053 struct mem_cgroup_thresholds *thresholds;
4054 struct mem_cgroup_threshold_ary *new;
4055 int type = MEMFILE_TYPE(cft->private);
4059 mutex_lock(&memcg->thresholds_lock);
4061 thresholds = &memcg->thresholds;
4062 else if (type == _MEMSWAP)
4063 thresholds = &memcg->memsw_thresholds;
4068 * Something went wrong if we trying to unregister a threshold
4069 * if we don't have thresholds
4071 BUG_ON(!thresholds);
4073 usage = mem_cgroup_usage(memcg, type == _MEMSWAP);
4075 /* Check if a threshold crossed before removing */
4076 __mem_cgroup_threshold(memcg, type == _MEMSWAP);
4078 /* Calculate new number of threshold */
4080 for (i = 0; i < thresholds->primary->size; i++) {
4081 if (thresholds->primary->entries[i].eventfd != eventfd)
4085 new = thresholds->spare;
4087 /* Set thresholds array to NULL if we don't have thresholds */
4096 /* Copy thresholds and find current threshold */
4097 new->current_threshold = -1;
4098 for (i = 0, j = 0; i < thresholds->primary->size; i++) {
4099 if (thresholds->primary->entries[i].eventfd == eventfd)
4102 new->entries[j] = thresholds->primary->entries[i];
4103 if (new->entries[j].threshold < usage) {
4105 * new->current_threshold will not be used
4106 * until rcu_assign_pointer(), so it's safe to increment
4109 ++new->current_threshold;
4115 /* Swap primary and spare array */
4116 thresholds->spare = thresholds->primary;
4117 rcu_assign_pointer(thresholds->primary, new);
4119 /* To be sure that nobody uses thresholds */
4122 mutex_unlock(&memcg->thresholds_lock);
4125 static int mem_cgroup_oom_register_event(struct cgroup *cgrp,
4126 struct cftype *cft, struct eventfd_ctx *eventfd, const char *args)
4128 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
4129 struct mem_cgroup_eventfd_list *event;
4130 int type = MEMFILE_TYPE(cft->private);
4132 BUG_ON(type != _OOM_TYPE);
4133 event = kmalloc(sizeof(*event), GFP_KERNEL);
4137 mutex_lock(&memcg_oom_mutex);
4139 event->eventfd = eventfd;
4140 list_add(&event->list, &memcg->oom_notify);
4142 /* already in OOM ? */
4143 if (atomic_read(&memcg->oom_lock))
4144 eventfd_signal(eventfd, 1);
4145 mutex_unlock(&memcg_oom_mutex);
4150 static void mem_cgroup_oom_unregister_event(struct cgroup *cgrp,
4151 struct cftype *cft, struct eventfd_ctx *eventfd)
4153 struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp);
4154 struct mem_cgroup_eventfd_list *ev, *tmp;
4155 int type = MEMFILE_TYPE(cft->private);
4157 BUG_ON(type != _OOM_TYPE);
4159 mutex_lock(&memcg_oom_mutex);
4161 list_for_each_entry_safe(ev, tmp, &mem->oom_notify, list) {
4162 if (ev->eventfd == eventfd) {
4163 list_del(&ev->list);
4168 mutex_unlock(&memcg_oom_mutex);
4171 static int mem_cgroup_oom_control_read(struct cgroup *cgrp,
4172 struct cftype *cft, struct cgroup_map_cb *cb)
4174 struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp);
4176 cb->fill(cb, "oom_kill_disable", mem->oom_kill_disable);
4178 if (atomic_read(&mem->oom_lock))
4179 cb->fill(cb, "under_oom", 1);
4181 cb->fill(cb, "under_oom", 0);
4185 static int mem_cgroup_oom_control_write(struct cgroup *cgrp,
4186 struct cftype *cft, u64 val)
4188 struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp);
4189 struct mem_cgroup *parent;
4191 /* cannot set to root cgroup and only 0 and 1 are allowed */
4192 if (!cgrp->parent || !((val == 0) || (val == 1)))
4195 parent = mem_cgroup_from_cont(cgrp->parent);
4198 /* oom-kill-disable is a flag for subhierarchy. */
4199 if ((parent->use_hierarchy) ||
4200 (mem->use_hierarchy && !list_empty(&cgrp->children))) {
4204 mem->oom_kill_disable = val;
4206 memcg_oom_recover(mem);
4211 static struct cftype mem_cgroup_files[] = {
4213 .name = "usage_in_bytes",
4214 .private = MEMFILE_PRIVATE(_MEM, RES_USAGE),
4215 .read_u64 = mem_cgroup_read,
4216 .register_event = mem_cgroup_usage_register_event,
4217 .unregister_event = mem_cgroup_usage_unregister_event,
4220 .name = "max_usage_in_bytes",
4221 .private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE),
4222 .trigger = mem_cgroup_reset,
4223 .read_u64 = mem_cgroup_read,
4226 .name = "limit_in_bytes",
4227 .private = MEMFILE_PRIVATE(_MEM, RES_LIMIT),
4228 .write_string = mem_cgroup_write,
4229 .read_u64 = mem_cgroup_read,
4232 .name = "soft_limit_in_bytes",
4233 .private = MEMFILE_PRIVATE(_MEM, RES_SOFT_LIMIT),
4234 .write_string = mem_cgroup_write,
4235 .read_u64 = mem_cgroup_read,
4239 .private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT),
4240 .trigger = mem_cgroup_reset,
4241 .read_u64 = mem_cgroup_read,
4245 .read_map = mem_control_stat_show,
4248 .name = "force_empty",
4249 .trigger = mem_cgroup_force_empty_write,
4252 .name = "use_hierarchy",
4253 .write_u64 = mem_cgroup_hierarchy_write,
4254 .read_u64 = mem_cgroup_hierarchy_read,
4257 .name = "swappiness",
4258 .read_u64 = mem_cgroup_swappiness_read,
4259 .write_u64 = mem_cgroup_swappiness_write,
4262 .name = "move_charge_at_immigrate",
4263 .read_u64 = mem_cgroup_move_charge_read,
4264 .write_u64 = mem_cgroup_move_charge_write,
4267 .name = "oom_control",
4268 .read_map = mem_cgroup_oom_control_read,
4269 .write_u64 = mem_cgroup_oom_control_write,
4270 .register_event = mem_cgroup_oom_register_event,
4271 .unregister_event = mem_cgroup_oom_unregister_event,
4272 .private = MEMFILE_PRIVATE(_OOM_TYPE, OOM_CONTROL),
4276 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
4277 static struct cftype memsw_cgroup_files[] = {
4279 .name = "memsw.usage_in_bytes",
4280 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE),
4281 .read_u64 = mem_cgroup_read,
4282 .register_event = mem_cgroup_usage_register_event,
4283 .unregister_event = mem_cgroup_usage_unregister_event,
4286 .name = "memsw.max_usage_in_bytes",
4287 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE),
4288 .trigger = mem_cgroup_reset,
4289 .read_u64 = mem_cgroup_read,
4292 .name = "memsw.limit_in_bytes",
4293 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT),
4294 .write_string = mem_cgroup_write,
4295 .read_u64 = mem_cgroup_read,
4298 .name = "memsw.failcnt",
4299 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT),
4300 .trigger = mem_cgroup_reset,
4301 .read_u64 = mem_cgroup_read,
4305 static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss)
4307 if (!do_swap_account)
4309 return cgroup_add_files(cont, ss, memsw_cgroup_files,
4310 ARRAY_SIZE(memsw_cgroup_files));
4313 static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss)
4319 static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
4321 struct mem_cgroup_per_node *pn;
4322 struct mem_cgroup_per_zone *mz;
4324 int zone, tmp = node;
4326 * This routine is called against possible nodes.
4327 * But it's BUG to call kmalloc() against offline node.
4329 * TODO: this routine can waste much memory for nodes which will
4330 * never be onlined. It's better to use memory hotplug callback
4333 if (!node_state(node, N_NORMAL_MEMORY))
4335 pn = kzalloc_node(sizeof(*pn), GFP_KERNEL, tmp);
4339 mem->info.nodeinfo[node] = pn;
4340 for (zone = 0; zone < MAX_NR_ZONES; zone++) {
4341 mz = &pn->zoneinfo[zone];
4343 INIT_LIST_HEAD(&mz->lists[l]);
4344 mz->usage_in_excess = 0;
4345 mz->on_tree = false;
4351 static void free_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
4353 kfree(mem->info.nodeinfo[node]);
4356 static struct mem_cgroup *mem_cgroup_alloc(void)
4358 struct mem_cgroup *mem;
4359 int size = sizeof(struct mem_cgroup);
4361 /* Can be very big if MAX_NUMNODES is very big */
4362 if (size < PAGE_SIZE)
4363 mem = kzalloc(size, GFP_KERNEL);
4365 mem = vzalloc(size);
4370 mem->stat = alloc_percpu(struct mem_cgroup_stat_cpu);
4373 spin_lock_init(&mem->pcp_counter_lock);
4377 if (size < PAGE_SIZE)
4385 * At destroying mem_cgroup, references from swap_cgroup can remain.
4386 * (scanning all at force_empty is too costly...)
4388 * Instead of clearing all references at force_empty, we remember
4389 * the number of reference from swap_cgroup and free mem_cgroup when
4390 * it goes down to 0.
4392 * Removal of cgroup itself succeeds regardless of refs from swap.
4395 static void __mem_cgroup_free(struct mem_cgroup *mem)
4399 mem_cgroup_remove_from_trees(mem);
4400 free_css_id(&mem_cgroup_subsys, &mem->css);
4402 for_each_node_state(node, N_POSSIBLE)
4403 free_mem_cgroup_per_zone_info(mem, node);
4405 free_percpu(mem->stat);
4406 if (sizeof(struct mem_cgroup) < PAGE_SIZE)
4412 static void mem_cgroup_get(struct mem_cgroup *mem)
4414 atomic_inc(&mem->refcnt);
4417 static void __mem_cgroup_put(struct mem_cgroup *mem, int count)
4419 if (atomic_sub_and_test(count, &mem->refcnt)) {
4420 struct mem_cgroup *parent = parent_mem_cgroup(mem);
4421 __mem_cgroup_free(mem);
4423 mem_cgroup_put(parent);
4427 static void mem_cgroup_put(struct mem_cgroup *mem)
4429 __mem_cgroup_put(mem, 1);
4433 * Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled.
4435 static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem)
4437 if (!mem->res.parent)
4439 return mem_cgroup_from_res_counter(mem->res.parent, res);
4442 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
4443 static void __init enable_swap_cgroup(void)
4445 if (!mem_cgroup_disabled() && really_do_swap_account)
4446 do_swap_account = 1;
4449 static void __init enable_swap_cgroup(void)
4454 static int mem_cgroup_soft_limit_tree_init(void)
4456 struct mem_cgroup_tree_per_node *rtpn;
4457 struct mem_cgroup_tree_per_zone *rtpz;
4458 int tmp, node, zone;
4460 for_each_node_state(node, N_POSSIBLE) {
4462 if (!node_state(node, N_NORMAL_MEMORY))
4464 rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL, tmp);
4468 soft_limit_tree.rb_tree_per_node[node] = rtpn;
4470 for (zone = 0; zone < MAX_NR_ZONES; zone++) {
4471 rtpz = &rtpn->rb_tree_per_zone[zone];
4472 rtpz->rb_root = RB_ROOT;
4473 spin_lock_init(&rtpz->lock);
4479 static struct cgroup_subsys_state * __ref
4480 mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
4482 struct mem_cgroup *mem, *parent;
4483 long error = -ENOMEM;
4486 mem = mem_cgroup_alloc();
4488 return ERR_PTR(error);
4490 for_each_node_state(node, N_POSSIBLE)
4491 if (alloc_mem_cgroup_per_zone_info(mem, node))
4495 if (cont->parent == NULL) {
4497 enable_swap_cgroup();
4499 root_mem_cgroup = mem;
4500 if (mem_cgroup_soft_limit_tree_init())
4502 for_each_possible_cpu(cpu) {
4503 struct memcg_stock_pcp *stock =
4504 &per_cpu(memcg_stock, cpu);
4505 INIT_WORK(&stock->work, drain_local_stock);
4507 hotcpu_notifier(memcg_cpu_hotplug_callback, 0);
4509 parent = mem_cgroup_from_cont(cont->parent);
4510 mem->use_hierarchy = parent->use_hierarchy;
4511 mem->oom_kill_disable = parent->oom_kill_disable;
4514 if (parent && parent->use_hierarchy) {
4515 res_counter_init(&mem->res, &parent->res);
4516 res_counter_init(&mem->memsw, &parent->memsw);
4518 * We increment refcnt of the parent to ensure that we can
4519 * safely access it on res_counter_charge/uncharge.
4520 * This refcnt will be decremented when freeing this
4521 * mem_cgroup(see mem_cgroup_put).
4523 mem_cgroup_get(parent);
4525 res_counter_init(&mem->res, NULL);
4526 res_counter_init(&mem->memsw, NULL);
4528 mem->last_scanned_child = 0;
4529 spin_lock_init(&mem->reclaim_param_lock);
4530 INIT_LIST_HEAD(&mem->oom_notify);
4533 mem->swappiness = get_swappiness(parent);
4534 atomic_set(&mem->refcnt, 1);
4535 mem->move_charge_at_immigrate = 0;
4536 mutex_init(&mem->thresholds_lock);
4539 __mem_cgroup_free(mem);
4540 root_mem_cgroup = NULL;
4541 return ERR_PTR(error);
4544 static int mem_cgroup_pre_destroy(struct cgroup_subsys *ss,
4545 struct cgroup *cont)
4547 struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
4549 return mem_cgroup_force_empty(mem, false);
4552 static void mem_cgroup_destroy(struct cgroup_subsys *ss,
4553 struct cgroup *cont)
4555 struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
4557 mem_cgroup_put(mem);
4560 static int mem_cgroup_populate(struct cgroup_subsys *ss,
4561 struct cgroup *cont)
4565 ret = cgroup_add_files(cont, ss, mem_cgroup_files,
4566 ARRAY_SIZE(mem_cgroup_files));
4569 ret = register_memsw_files(cont, ss);
4574 /* Handlers for move charge at task migration. */
4575 #define PRECHARGE_COUNT_AT_ONCE 256
4576 static int mem_cgroup_do_precharge(unsigned long count)
4579 int batch_count = PRECHARGE_COUNT_AT_ONCE;
4580 struct mem_cgroup *mem = mc.to;
4582 if (mem_cgroup_is_root(mem)) {
4583 mc.precharge += count;
4584 /* we don't need css_get for root */
4587 /* try to charge at once */
4589 struct res_counter *dummy;
4591 * "mem" cannot be under rmdir() because we've already checked
4592 * by cgroup_lock_live_cgroup() that it is not removed and we
4593 * are still under the same cgroup_mutex. So we can postpone
4596 if (res_counter_charge(&mem->res, PAGE_SIZE * count, &dummy))
4598 if (do_swap_account && res_counter_charge(&mem->memsw,
4599 PAGE_SIZE * count, &dummy)) {
4600 res_counter_uncharge(&mem->res, PAGE_SIZE * count);
4603 mc.precharge += count;
4607 /* fall back to one by one charge */
4609 if (signal_pending(current)) {
4613 if (!batch_count--) {
4614 batch_count = PRECHARGE_COUNT_AT_ONCE;
4617 ret = __mem_cgroup_try_charge(NULL, GFP_KERNEL, &mem, false,
4620 /* mem_cgroup_clear_mc() will do uncharge later */
4628 * is_target_pte_for_mc - check a pte whether it is valid for move charge
4629 * @vma: the vma the pte to be checked belongs
4630 * @addr: the address corresponding to the pte to be checked
4631 * @ptent: the pte to be checked
4632 * @target: the pointer the target page or swap ent will be stored(can be NULL)
4635 * 0(MC_TARGET_NONE): if the pte is not a target for move charge.
4636 * 1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for
4637 * move charge. if @target is not NULL, the page is stored in target->page
4638 * with extra refcnt got(Callers should handle it).
4639 * 2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a
4640 * target for charge migration. if @target is not NULL, the entry is stored
4643 * Called with pte lock held.
4650 enum mc_target_type {
4651 MC_TARGET_NONE, /* not used */
4656 static struct page *mc_handle_present_pte(struct vm_area_struct *vma,
4657 unsigned long addr, pte_t ptent)
4659 struct page *page = vm_normal_page(vma, addr, ptent);
4661 if (!page || !page_mapped(page))
4663 if (PageAnon(page)) {
4664 /* we don't move shared anon */
4665 if (!move_anon() || page_mapcount(page) > 2)
4667 } else if (!move_file())
4668 /* we ignore mapcount for file pages */
4670 if (!get_page_unless_zero(page))
4676 static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
4677 unsigned long addr, pte_t ptent, swp_entry_t *entry)
4680 struct page *page = NULL;
4681 swp_entry_t ent = pte_to_swp_entry(ptent);
4683 if (!move_anon() || non_swap_entry(ent))
4685 usage_count = mem_cgroup_count_swap_user(ent, &page);
4686 if (usage_count > 1) { /* we don't move shared anon */
4691 if (do_swap_account)
4692 entry->val = ent.val;
4697 static struct page *mc_handle_file_pte(struct vm_area_struct *vma,
4698 unsigned long addr, pte_t ptent, swp_entry_t *entry)
4700 struct page *page = NULL;
4701 struct inode *inode;
4702 struct address_space *mapping;
4705 if (!vma->vm_file) /* anonymous vma */
4710 inode = vma->vm_file->f_path.dentry->d_inode;
4711 mapping = vma->vm_file->f_mapping;
4712 if (pte_none(ptent))
4713 pgoff = linear_page_index(vma, addr);
4714 else /* pte_file(ptent) is true */
4715 pgoff = pte_to_pgoff(ptent);
4717 /* page is moved even if it's not RSS of this task(page-faulted). */
4718 if (!mapping_cap_swap_backed(mapping)) { /* normal file */
4719 page = find_get_page(mapping, pgoff);
4720 } else { /* shmem/tmpfs file. we should take account of swap too. */
4722 mem_cgroup_get_shmem_target(inode, pgoff, &page, &ent);
4723 if (do_swap_account)
4724 entry->val = ent.val;
4730 static int is_target_pte_for_mc(struct vm_area_struct *vma,
4731 unsigned long addr, pte_t ptent, union mc_target *target)
4733 struct page *page = NULL;
4734 struct page_cgroup *pc;
4736 swp_entry_t ent = { .val = 0 };
4738 if (pte_present(ptent))
4739 page = mc_handle_present_pte(vma, addr, ptent);
4740 else if (is_swap_pte(ptent))
4741 page = mc_handle_swap_pte(vma, addr, ptent, &ent);
4742 else if (pte_none(ptent) || pte_file(ptent))
4743 page = mc_handle_file_pte(vma, addr, ptent, &ent);
4745 if (!page && !ent.val)
4748 pc = lookup_page_cgroup(page);
4750 * Do only loose check w/o page_cgroup lock.
4751 * mem_cgroup_move_account() checks the pc is valid or not under
4754 if (PageCgroupUsed(pc) && pc->mem_cgroup == mc.from) {
4755 ret = MC_TARGET_PAGE;
4757 target->page = page;
4759 if (!ret || !target)
4762 /* There is a swap entry and a page doesn't exist or isn't charged */
4763 if (ent.val && !ret &&
4764 css_id(&mc.from->css) == lookup_swap_cgroup(ent)) {
4765 ret = MC_TARGET_SWAP;
4772 static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd,
4773 unsigned long addr, unsigned long end,
4774 struct mm_walk *walk)
4776 struct vm_area_struct *vma = walk->private;
4780 split_huge_page_pmd(walk->mm, pmd);
4782 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
4783 for (; addr != end; pte++, addr += PAGE_SIZE)
4784 if (is_target_pte_for_mc(vma, addr, *pte, NULL))
4785 mc.precharge++; /* increment precharge temporarily */
4786 pte_unmap_unlock(pte - 1, ptl);
4792 static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm)
4794 unsigned long precharge;
4795 struct vm_area_struct *vma;
4797 down_read(&mm->mmap_sem);
4798 for (vma = mm->mmap; vma; vma = vma->vm_next) {
4799 struct mm_walk mem_cgroup_count_precharge_walk = {
4800 .pmd_entry = mem_cgroup_count_precharge_pte_range,
4804 if (is_vm_hugetlb_page(vma))
4806 walk_page_range(vma->vm_start, vma->vm_end,
4807 &mem_cgroup_count_precharge_walk);
4809 up_read(&mm->mmap_sem);
4811 precharge = mc.precharge;
4817 static int mem_cgroup_precharge_mc(struct mm_struct *mm)
4819 unsigned long precharge = mem_cgroup_count_precharge(mm);
4821 VM_BUG_ON(mc.moving_task);
4822 mc.moving_task = current;
4823 return mem_cgroup_do_precharge(precharge);
4826 /* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */
4827 static void __mem_cgroup_clear_mc(void)
4829 struct mem_cgroup *from = mc.from;
4830 struct mem_cgroup *to = mc.to;
4832 /* we must uncharge all the leftover precharges from mc.to */
4834 __mem_cgroup_cancel_charge(mc.to, mc.precharge);
4838 * we didn't uncharge from mc.from at mem_cgroup_move_account(), so
4839 * we must uncharge here.
4841 if (mc.moved_charge) {
4842 __mem_cgroup_cancel_charge(mc.from, mc.moved_charge);
4843 mc.moved_charge = 0;
4845 /* we must fixup refcnts and charges */
4846 if (mc.moved_swap) {
4847 /* uncharge swap account from the old cgroup */
4848 if (!mem_cgroup_is_root(mc.from))
4849 res_counter_uncharge(&mc.from->memsw,
4850 PAGE_SIZE * mc.moved_swap);
4851 __mem_cgroup_put(mc.from, mc.moved_swap);
4853 if (!mem_cgroup_is_root(mc.to)) {
4855 * we charged both to->res and to->memsw, so we should
4858 res_counter_uncharge(&mc.to->res,
4859 PAGE_SIZE * mc.moved_swap);
4861 /* we've already done mem_cgroup_get(mc.to) */
4864 memcg_oom_recover(from);
4865 memcg_oom_recover(to);
4866 wake_up_all(&mc.waitq);
4869 static void mem_cgroup_clear_mc(void)
4871 struct mem_cgroup *from = mc.from;
4874 * we must clear moving_task before waking up waiters at the end of
4877 mc.moving_task = NULL;
4878 __mem_cgroup_clear_mc();
4879 spin_lock(&mc.lock);
4882 spin_unlock(&mc.lock);
4883 mem_cgroup_end_move(from);
4886 static int mem_cgroup_can_attach(struct cgroup_subsys *ss,
4887 struct cgroup *cgroup,
4888 struct task_struct *p,
4892 struct mem_cgroup *mem = mem_cgroup_from_cont(cgroup);
4894 if (mem->move_charge_at_immigrate) {
4895 struct mm_struct *mm;
4896 struct mem_cgroup *from = mem_cgroup_from_task(p);
4898 VM_BUG_ON(from == mem);
4900 mm = get_task_mm(p);
4903 /* We move charges only when we move a owner of the mm */
4904 if (mm->owner == p) {
4907 VM_BUG_ON(mc.precharge);
4908 VM_BUG_ON(mc.moved_charge);
4909 VM_BUG_ON(mc.moved_swap);
4910 mem_cgroup_start_move(from);
4911 spin_lock(&mc.lock);
4914 spin_unlock(&mc.lock);
4915 /* We set mc.moving_task later */
4917 ret = mem_cgroup_precharge_mc(mm);
4919 mem_cgroup_clear_mc();
4926 static void mem_cgroup_cancel_attach(struct cgroup_subsys *ss,
4927 struct cgroup *cgroup,
4928 struct task_struct *p,
4931 mem_cgroup_clear_mc();
4934 static int mem_cgroup_move_charge_pte_range(pmd_t *pmd,
4935 unsigned long addr, unsigned long end,
4936 struct mm_walk *walk)
4939 struct vm_area_struct *vma = walk->private;
4943 split_huge_page_pmd(walk->mm, pmd);
4945 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
4946 for (; addr != end; addr += PAGE_SIZE) {
4947 pte_t ptent = *(pte++);
4948 union mc_target target;
4951 struct page_cgroup *pc;
4957 type = is_target_pte_for_mc(vma, addr, ptent, &target);
4959 case MC_TARGET_PAGE:
4961 if (isolate_lru_page(page))
4963 pc = lookup_page_cgroup(page);
4964 if (!mem_cgroup_move_account(page, pc,
4965 mc.from, mc.to, false, PAGE_SIZE)) {
4967 /* we uncharge from mc.from later. */
4970 putback_lru_page(page);
4971 put: /* is_target_pte_for_mc() gets the page */
4974 case MC_TARGET_SWAP:
4976 if (!mem_cgroup_move_swap_account(ent,
4977 mc.from, mc.to, false)) {
4979 /* we fixup refcnts and charges later. */
4987 pte_unmap_unlock(pte - 1, ptl);
4992 * We have consumed all precharges we got in can_attach().
4993 * We try charge one by one, but don't do any additional
4994 * charges to mc.to if we have failed in charge once in attach()
4997 ret = mem_cgroup_do_precharge(1);
5005 static void mem_cgroup_move_charge(struct mm_struct *mm)
5007 struct vm_area_struct *vma;
5009 lru_add_drain_all();
5011 if (unlikely(!down_read_trylock(&mm->mmap_sem))) {
5013 * Someone who are holding the mmap_sem might be waiting in
5014 * waitq. So we cancel all extra charges, wake up all waiters,
5015 * and retry. Because we cancel precharges, we might not be able
5016 * to move enough charges, but moving charge is a best-effort
5017 * feature anyway, so it wouldn't be a big problem.
5019 __mem_cgroup_clear_mc();
5023 for (vma = mm->mmap; vma; vma = vma->vm_next) {
5025 struct mm_walk mem_cgroup_move_charge_walk = {
5026 .pmd_entry = mem_cgroup_move_charge_pte_range,
5030 if (is_vm_hugetlb_page(vma))
5032 ret = walk_page_range(vma->vm_start, vma->vm_end,
5033 &mem_cgroup_move_charge_walk);
5036 * means we have consumed all precharges and failed in
5037 * doing additional charge. Just abandon here.
5041 up_read(&mm->mmap_sem);
5044 static void mem_cgroup_move_task(struct cgroup_subsys *ss,
5045 struct cgroup *cont,
5046 struct cgroup *old_cont,
5047 struct task_struct *p,
5050 struct mm_struct *mm;
5053 /* no need to move charge */
5056 mm = get_task_mm(p);
5058 mem_cgroup_move_charge(mm);
5061 mem_cgroup_clear_mc();
5063 #else /* !CONFIG_MMU */
5064 static int mem_cgroup_can_attach(struct cgroup_subsys *ss,
5065 struct cgroup *cgroup,
5066 struct task_struct *p,
5071 static void mem_cgroup_cancel_attach(struct cgroup_subsys *ss,
5072 struct cgroup *cgroup,
5073 struct task_struct *p,
5077 static void mem_cgroup_move_task(struct cgroup_subsys *ss,
5078 struct cgroup *cont,
5079 struct cgroup *old_cont,
5080 struct task_struct *p,
5086 struct cgroup_subsys mem_cgroup_subsys = {
5088 .subsys_id = mem_cgroup_subsys_id,
5089 .create = mem_cgroup_create,
5090 .pre_destroy = mem_cgroup_pre_destroy,
5091 .destroy = mem_cgroup_destroy,
5092 .populate = mem_cgroup_populate,
5093 .can_attach = mem_cgroup_can_attach,
5094 .cancel_attach = mem_cgroup_cancel_attach,
5095 .attach = mem_cgroup_move_task,
5100 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
5101 static int __init enable_swap_account(char *s)
5103 /* consider enabled if no parameter or 1 is given */
5104 if (!(*s) || !strcmp(s, "=1"))
5105 really_do_swap_account = 1;
5106 else if (!strcmp(s, "=0"))
5107 really_do_swap_account = 0;
5110 __setup("swapaccount", enable_swap_account);
5112 static int __init disable_swap_account(char *s)
5114 printk_once("noswapaccount is deprecated and will be removed in 2.6.40. Use swapaccount=0 instead\n");
5115 enable_swap_account("=0");
5118 __setup("noswapaccount", disable_swap_account);