viafb: Eliminate some global.h references
[linux/fpc-iii.git] / mm / memcontrol.c
blob9ed760dc74481a7436e3ab7b084ff8abd233ee01
1 /* memcontrol.c - Memory Controller
3 * Copyright IBM Corporation, 2007
4 * Author Balbir Singh <balbir@linux.vnet.ibm.com>
6 * Copyright 2007 OpenVZ SWsoft Inc
7 * Author: Pavel Emelianov <xemul@openvz.org>
9 * Memory thresholds
10 * Copyright (C) 2009 Nokia Corporation
11 * Author: Kirill A. Shutemov
13 * This program is free software; you can redistribute it and/or modify
14 * it under the terms of the GNU General Public License as published by
15 * the Free Software Foundation; either version 2 of the License, or
16 * (at your option) any later version.
18 * This program is distributed in the hope that it will be useful,
19 * but WITHOUT ANY WARRANTY; without even the implied warranty of
20 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
21 * GNU General Public License for more details.
24 #include <linux/res_counter.h>
25 #include <linux/memcontrol.h>
26 #include <linux/cgroup.h>
27 #include <linux/mm.h>
28 #include <linux/hugetlb.h>
29 #include <linux/pagemap.h>
30 #include <linux/smp.h>
31 #include <linux/page-flags.h>
32 #include <linux/backing-dev.h>
33 #include <linux/bit_spinlock.h>
34 #include <linux/rcupdate.h>
35 #include <linux/limits.h>
36 #include <linux/mutex.h>
37 #include <linux/rbtree.h>
38 #include <linux/slab.h>
39 #include <linux/swap.h>
40 #include <linux/swapops.h>
41 #include <linux/spinlock.h>
42 #include <linux/eventfd.h>
43 #include <linux/sort.h>
44 #include <linux/fs.h>
45 #include <linux/seq_file.h>
46 #include <linux/vmalloc.h>
47 #include <linux/mm_inline.h>
48 #include <linux/page_cgroup.h>
49 #include <linux/cpu.h>
50 #include "internal.h"
52 #include <asm/uaccess.h>
54 struct cgroup_subsys mem_cgroup_subsys __read_mostly;
55 #define MEM_CGROUP_RECLAIM_RETRIES 5
56 struct mem_cgroup *root_mem_cgroup __read_mostly;
58 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
59 /* Turned on only when memory cgroup is enabled && really_do_swap_account = 1 */
60 int do_swap_account __read_mostly;
61 static int really_do_swap_account __initdata = 1; /* for remember boot option*/
62 #else
63 #define do_swap_account (0)
64 #endif
67 * Per memcg event counter is incremented at every pagein/pageout. This counter
68 * is used for trigger some periodic events. This is straightforward and better
69 * than using jiffies etc. to handle periodic memcg event.
71 * These values will be used as !((event) & ((1 <<(thresh)) - 1))
73 #define THRESHOLDS_EVENTS_THRESH (7) /* once in 128 */
74 #define SOFTLIMIT_EVENTS_THRESH (10) /* once in 1024 */
77 * Statistics for memory cgroup.
79 enum mem_cgroup_stat_index {
81 * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss.
83 MEM_CGROUP_STAT_CACHE, /* # of pages charged as cache */
84 MEM_CGROUP_STAT_RSS, /* # of pages charged as anon rss */
85 MEM_CGROUP_STAT_FILE_MAPPED, /* # of pages charged as file rss */
86 MEM_CGROUP_STAT_PGPGIN_COUNT, /* # of pages paged in */
87 MEM_CGROUP_STAT_PGPGOUT_COUNT, /* # of pages paged out */
88 MEM_CGROUP_STAT_SWAPOUT, /* # of pages, swapped out */
89 MEM_CGROUP_EVENTS, /* incremented at every pagein/pageout */
91 MEM_CGROUP_STAT_NSTATS,
94 struct mem_cgroup_stat_cpu {
95 s64 count[MEM_CGROUP_STAT_NSTATS];
99 * per-zone information in memory controller.
101 struct mem_cgroup_per_zone {
103 * spin_lock to protect the per cgroup LRU
105 struct list_head lists[NR_LRU_LISTS];
106 unsigned long count[NR_LRU_LISTS];
108 struct zone_reclaim_stat reclaim_stat;
109 struct rb_node tree_node; /* RB tree node */
110 unsigned long long usage_in_excess;/* Set to the value by which */
111 /* the soft limit is exceeded*/
112 bool on_tree;
113 struct mem_cgroup *mem; /* Back pointer, we cannot */
114 /* use container_of */
116 /* Macro for accessing counter */
117 #define MEM_CGROUP_ZSTAT(mz, idx) ((mz)->count[(idx)])
119 struct mem_cgroup_per_node {
120 struct mem_cgroup_per_zone zoneinfo[MAX_NR_ZONES];
123 struct mem_cgroup_lru_info {
124 struct mem_cgroup_per_node *nodeinfo[MAX_NUMNODES];
128 * Cgroups above their limits are maintained in a RB-Tree, independent of
129 * their hierarchy representation
132 struct mem_cgroup_tree_per_zone {
133 struct rb_root rb_root;
134 spinlock_t lock;
137 struct mem_cgroup_tree_per_node {
138 struct mem_cgroup_tree_per_zone rb_tree_per_zone[MAX_NR_ZONES];
141 struct mem_cgroup_tree {
142 struct mem_cgroup_tree_per_node *rb_tree_per_node[MAX_NUMNODES];
145 static struct mem_cgroup_tree soft_limit_tree __read_mostly;
147 struct mem_cgroup_threshold {
148 struct eventfd_ctx *eventfd;
149 u64 threshold;
152 struct mem_cgroup_threshold_ary {
153 /* An array index points to threshold just below usage. */
154 atomic_t current_threshold;
155 /* Size of entries[] */
156 unsigned int size;
157 /* Array of thresholds */
158 struct mem_cgroup_threshold entries[0];
161 static void mem_cgroup_threshold(struct mem_cgroup *mem);
164 * The memory controller data structure. The memory controller controls both
165 * page cache and RSS per cgroup. We would eventually like to provide
166 * statistics based on the statistics developed by Rik Van Riel for clock-pro,
167 * to help the administrator determine what knobs to tune.
169 * TODO: Add a water mark for the memory controller. Reclaim will begin when
170 * we hit the water mark. May be even add a low water mark, such that
171 * no reclaim occurs from a cgroup at it's low water mark, this is
172 * a feature that will be implemented much later in the future.
174 struct mem_cgroup {
175 struct cgroup_subsys_state css;
177 * the counter to account for memory usage
179 struct res_counter res;
181 * the counter to account for mem+swap usage.
183 struct res_counter memsw;
185 * Per cgroup active and inactive list, similar to the
186 * per zone LRU lists.
188 struct mem_cgroup_lru_info info;
191 protect against reclaim related member.
193 spinlock_t reclaim_param_lock;
195 int prev_priority; /* for recording reclaim priority */
198 * While reclaiming in a hierarchy, we cache the last child we
199 * reclaimed from.
201 int last_scanned_child;
203 * Should the accounting and control be hierarchical, per subtree?
205 bool use_hierarchy;
206 atomic_t oom_lock;
207 atomic_t refcnt;
209 unsigned int swappiness;
211 /* set when res.limit == memsw.limit */
212 bool memsw_is_minimum;
214 /* protect arrays of thresholds */
215 struct mutex thresholds_lock;
217 /* thresholds for memory usage. RCU-protected */
218 struct mem_cgroup_threshold_ary *thresholds;
220 /* thresholds for mem+swap usage. RCU-protected */
221 struct mem_cgroup_threshold_ary *memsw_thresholds;
224 * Should we move charges of a task when a task is moved into this
225 * mem_cgroup ? And what type of charges should we move ?
227 unsigned long move_charge_at_immigrate;
230 * percpu counter.
232 struct mem_cgroup_stat_cpu *stat;
235 /* Stuffs for move charges at task migration. */
237 * Types of charges to be moved. "move_charge_at_immitgrate" is treated as a
238 * left-shifted bitmap of these types.
240 enum move_type {
241 MOVE_CHARGE_TYPE_ANON, /* private anonymous page and swap of it */
242 NR_MOVE_TYPE,
245 /* "mc" and its members are protected by cgroup_mutex */
246 static struct move_charge_struct {
247 struct mem_cgroup *from;
248 struct mem_cgroup *to;
249 unsigned long precharge;
250 unsigned long moved_charge;
251 unsigned long moved_swap;
252 struct task_struct *moving_task; /* a task moving charges */
253 wait_queue_head_t waitq; /* a waitq for other context */
254 } mc = {
255 .waitq = __WAIT_QUEUE_HEAD_INITIALIZER(mc.waitq),
259 * Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft
260 * limit reclaim to prevent infinite loops, if they ever occur.
262 #define MEM_CGROUP_MAX_RECLAIM_LOOPS (100)
263 #define MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS (2)
265 enum charge_type {
266 MEM_CGROUP_CHARGE_TYPE_CACHE = 0,
267 MEM_CGROUP_CHARGE_TYPE_MAPPED,
268 MEM_CGROUP_CHARGE_TYPE_SHMEM, /* used by page migration of shmem */
269 MEM_CGROUP_CHARGE_TYPE_FORCE, /* used by force_empty */
270 MEM_CGROUP_CHARGE_TYPE_SWAPOUT, /* for accounting swapcache */
271 MEM_CGROUP_CHARGE_TYPE_DROP, /* a page was unused swap cache */
272 NR_CHARGE_TYPE,
275 /* only for here (for easy reading.) */
276 #define PCGF_CACHE (1UL << PCG_CACHE)
277 #define PCGF_USED (1UL << PCG_USED)
278 #define PCGF_LOCK (1UL << PCG_LOCK)
279 /* Not used, but added here for completeness */
280 #define PCGF_ACCT (1UL << PCG_ACCT)
282 /* for encoding cft->private value on file */
283 #define _MEM (0)
284 #define _MEMSWAP (1)
285 #define MEMFILE_PRIVATE(x, val) (((x) << 16) | (val))
286 #define MEMFILE_TYPE(val) (((val) >> 16) & 0xffff)
287 #define MEMFILE_ATTR(val) ((val) & 0xffff)
290 * Reclaim flags for mem_cgroup_hierarchical_reclaim
292 #define MEM_CGROUP_RECLAIM_NOSWAP_BIT 0x0
293 #define MEM_CGROUP_RECLAIM_NOSWAP (1 << MEM_CGROUP_RECLAIM_NOSWAP_BIT)
294 #define MEM_CGROUP_RECLAIM_SHRINK_BIT 0x1
295 #define MEM_CGROUP_RECLAIM_SHRINK (1 << MEM_CGROUP_RECLAIM_SHRINK_BIT)
296 #define MEM_CGROUP_RECLAIM_SOFT_BIT 0x2
297 #define MEM_CGROUP_RECLAIM_SOFT (1 << MEM_CGROUP_RECLAIM_SOFT_BIT)
299 static void mem_cgroup_get(struct mem_cgroup *mem);
300 static void mem_cgroup_put(struct mem_cgroup *mem);
301 static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem);
302 static void drain_all_stock_async(void);
304 static struct mem_cgroup_per_zone *
305 mem_cgroup_zoneinfo(struct mem_cgroup *mem, int nid, int zid)
307 return &mem->info.nodeinfo[nid]->zoneinfo[zid];
310 struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *mem)
312 return &mem->css;
315 static struct mem_cgroup_per_zone *
316 page_cgroup_zoneinfo(struct page_cgroup *pc)
318 struct mem_cgroup *mem = pc->mem_cgroup;
319 int nid = page_cgroup_nid(pc);
320 int zid = page_cgroup_zid(pc);
322 if (!mem)
323 return NULL;
325 return mem_cgroup_zoneinfo(mem, nid, zid);
328 static struct mem_cgroup_tree_per_zone *
329 soft_limit_tree_node_zone(int nid, int zid)
331 return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid];
334 static struct mem_cgroup_tree_per_zone *
335 soft_limit_tree_from_page(struct page *page)
337 int nid = page_to_nid(page);
338 int zid = page_zonenum(page);
340 return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid];
343 static void
344 __mem_cgroup_insert_exceeded(struct mem_cgroup *mem,
345 struct mem_cgroup_per_zone *mz,
346 struct mem_cgroup_tree_per_zone *mctz,
347 unsigned long long new_usage_in_excess)
349 struct rb_node **p = &mctz->rb_root.rb_node;
350 struct rb_node *parent = NULL;
351 struct mem_cgroup_per_zone *mz_node;
353 if (mz->on_tree)
354 return;
356 mz->usage_in_excess = new_usage_in_excess;
357 if (!mz->usage_in_excess)
358 return;
359 while (*p) {
360 parent = *p;
361 mz_node = rb_entry(parent, struct mem_cgroup_per_zone,
362 tree_node);
363 if (mz->usage_in_excess < mz_node->usage_in_excess)
364 p = &(*p)->rb_left;
366 * We can't avoid mem cgroups that are over their soft
367 * limit by the same amount
369 else if (mz->usage_in_excess >= mz_node->usage_in_excess)
370 p = &(*p)->rb_right;
372 rb_link_node(&mz->tree_node, parent, p);
373 rb_insert_color(&mz->tree_node, &mctz->rb_root);
374 mz->on_tree = true;
377 static void
378 __mem_cgroup_remove_exceeded(struct mem_cgroup *mem,
379 struct mem_cgroup_per_zone *mz,
380 struct mem_cgroup_tree_per_zone *mctz)
382 if (!mz->on_tree)
383 return;
384 rb_erase(&mz->tree_node, &mctz->rb_root);
385 mz->on_tree = false;
388 static void
389 mem_cgroup_remove_exceeded(struct mem_cgroup *mem,
390 struct mem_cgroup_per_zone *mz,
391 struct mem_cgroup_tree_per_zone *mctz)
393 spin_lock(&mctz->lock);
394 __mem_cgroup_remove_exceeded(mem, mz, mctz);
395 spin_unlock(&mctz->lock);
399 static void mem_cgroup_update_tree(struct mem_cgroup *mem, struct page *page)
401 unsigned long long excess;
402 struct mem_cgroup_per_zone *mz;
403 struct mem_cgroup_tree_per_zone *mctz;
404 int nid = page_to_nid(page);
405 int zid = page_zonenum(page);
406 mctz = soft_limit_tree_from_page(page);
409 * Necessary to update all ancestors when hierarchy is used.
410 * because their event counter is not touched.
412 for (; mem; mem = parent_mem_cgroup(mem)) {
413 mz = mem_cgroup_zoneinfo(mem, nid, zid);
414 excess = res_counter_soft_limit_excess(&mem->res);
416 * We have to update the tree if mz is on RB-tree or
417 * mem is over its softlimit.
419 if (excess || mz->on_tree) {
420 spin_lock(&mctz->lock);
421 /* if on-tree, remove it */
422 if (mz->on_tree)
423 __mem_cgroup_remove_exceeded(mem, mz, mctz);
425 * Insert again. mz->usage_in_excess will be updated.
426 * If excess is 0, no tree ops.
428 __mem_cgroup_insert_exceeded(mem, mz, mctz, excess);
429 spin_unlock(&mctz->lock);
434 static void mem_cgroup_remove_from_trees(struct mem_cgroup *mem)
436 int node, zone;
437 struct mem_cgroup_per_zone *mz;
438 struct mem_cgroup_tree_per_zone *mctz;
440 for_each_node_state(node, N_POSSIBLE) {
441 for (zone = 0; zone < MAX_NR_ZONES; zone++) {
442 mz = mem_cgroup_zoneinfo(mem, node, zone);
443 mctz = soft_limit_tree_node_zone(node, zone);
444 mem_cgroup_remove_exceeded(mem, mz, mctz);
449 static inline unsigned long mem_cgroup_get_excess(struct mem_cgroup *mem)
451 return res_counter_soft_limit_excess(&mem->res) >> PAGE_SHIFT;
454 static struct mem_cgroup_per_zone *
455 __mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
457 struct rb_node *rightmost = NULL;
458 struct mem_cgroup_per_zone *mz;
460 retry:
461 mz = NULL;
462 rightmost = rb_last(&mctz->rb_root);
463 if (!rightmost)
464 goto done; /* Nothing to reclaim from */
466 mz = rb_entry(rightmost, struct mem_cgroup_per_zone, tree_node);
468 * Remove the node now but someone else can add it back,
469 * we will to add it back at the end of reclaim to its correct
470 * position in the tree.
472 __mem_cgroup_remove_exceeded(mz->mem, mz, mctz);
473 if (!res_counter_soft_limit_excess(&mz->mem->res) ||
474 !css_tryget(&mz->mem->css))
475 goto retry;
476 done:
477 return mz;
480 static struct mem_cgroup_per_zone *
481 mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
483 struct mem_cgroup_per_zone *mz;
485 spin_lock(&mctz->lock);
486 mz = __mem_cgroup_largest_soft_limit_node(mctz);
487 spin_unlock(&mctz->lock);
488 return mz;
491 static s64 mem_cgroup_read_stat(struct mem_cgroup *mem,
492 enum mem_cgroup_stat_index idx)
494 int cpu;
495 s64 val = 0;
497 for_each_possible_cpu(cpu)
498 val += per_cpu(mem->stat->count[idx], cpu);
499 return val;
502 static s64 mem_cgroup_local_usage(struct mem_cgroup *mem)
504 s64 ret;
506 ret = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_RSS);
507 ret += mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_CACHE);
508 return ret;
511 static void mem_cgroup_swap_statistics(struct mem_cgroup *mem,
512 bool charge)
514 int val = (charge) ? 1 : -1;
515 this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_SWAPOUT], val);
518 static void mem_cgroup_charge_statistics(struct mem_cgroup *mem,
519 struct page_cgroup *pc,
520 bool charge)
522 int val = (charge) ? 1 : -1;
524 preempt_disable();
526 if (PageCgroupCache(pc))
527 __this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_CACHE], val);
528 else
529 __this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_RSS], val);
531 if (charge)
532 __this_cpu_inc(mem->stat->count[MEM_CGROUP_STAT_PGPGIN_COUNT]);
533 else
534 __this_cpu_inc(mem->stat->count[MEM_CGROUP_STAT_PGPGOUT_COUNT]);
535 __this_cpu_inc(mem->stat->count[MEM_CGROUP_EVENTS]);
537 preempt_enable();
540 static unsigned long mem_cgroup_get_local_zonestat(struct mem_cgroup *mem,
541 enum lru_list idx)
543 int nid, zid;
544 struct mem_cgroup_per_zone *mz;
545 u64 total = 0;
547 for_each_online_node(nid)
548 for (zid = 0; zid < MAX_NR_ZONES; zid++) {
549 mz = mem_cgroup_zoneinfo(mem, nid, zid);
550 total += MEM_CGROUP_ZSTAT(mz, idx);
552 return total;
555 static bool __memcg_event_check(struct mem_cgroup *mem, int event_mask_shift)
557 s64 val;
559 val = this_cpu_read(mem->stat->count[MEM_CGROUP_EVENTS]);
561 return !(val & ((1 << event_mask_shift) - 1));
565 * Check events in order.
568 static void memcg_check_events(struct mem_cgroup *mem, struct page *page)
570 /* threshold event is triggered in finer grain than soft limit */
571 if (unlikely(__memcg_event_check(mem, THRESHOLDS_EVENTS_THRESH))) {
572 mem_cgroup_threshold(mem);
573 if (unlikely(__memcg_event_check(mem, SOFTLIMIT_EVENTS_THRESH)))
574 mem_cgroup_update_tree(mem, page);
578 static struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont)
580 return container_of(cgroup_subsys_state(cont,
581 mem_cgroup_subsys_id), struct mem_cgroup,
582 css);
585 struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
588 * mm_update_next_owner() may clear mm->owner to NULL
589 * if it races with swapoff, page migration, etc.
590 * So this can be called with p == NULL.
592 if (unlikely(!p))
593 return NULL;
595 return container_of(task_subsys_state(p, mem_cgroup_subsys_id),
596 struct mem_cgroup, css);
599 static struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm)
601 struct mem_cgroup *mem = NULL;
603 if (!mm)
604 return NULL;
606 * Because we have no locks, mm->owner's may be being moved to other
607 * cgroup. We use css_tryget() here even if this looks
608 * pessimistic (rather than adding locks here).
610 rcu_read_lock();
611 do {
612 mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
613 if (unlikely(!mem))
614 break;
615 } while (!css_tryget(&mem->css));
616 rcu_read_unlock();
617 return mem;
621 * Call callback function against all cgroup under hierarchy tree.
623 static int mem_cgroup_walk_tree(struct mem_cgroup *root, void *data,
624 int (*func)(struct mem_cgroup *, void *))
626 int found, ret, nextid;
627 struct cgroup_subsys_state *css;
628 struct mem_cgroup *mem;
630 if (!root->use_hierarchy)
631 return (*func)(root, data);
633 nextid = 1;
634 do {
635 ret = 0;
636 mem = NULL;
638 rcu_read_lock();
639 css = css_get_next(&mem_cgroup_subsys, nextid, &root->css,
640 &found);
641 if (css && css_tryget(css))
642 mem = container_of(css, struct mem_cgroup, css);
643 rcu_read_unlock();
645 if (mem) {
646 ret = (*func)(mem, data);
647 css_put(&mem->css);
649 nextid = found + 1;
650 } while (!ret && css);
652 return ret;
655 static inline bool mem_cgroup_is_root(struct mem_cgroup *mem)
657 return (mem == root_mem_cgroup);
661 * Following LRU functions are allowed to be used without PCG_LOCK.
662 * Operations are called by routine of global LRU independently from memcg.
663 * What we have to take care of here is validness of pc->mem_cgroup.
665 * Changes to pc->mem_cgroup happens when
666 * 1. charge
667 * 2. moving account
668 * In typical case, "charge" is done before add-to-lru. Exception is SwapCache.
669 * It is added to LRU before charge.
670 * If PCG_USED bit is not set, page_cgroup is not added to this private LRU.
671 * When moving account, the page is not on LRU. It's isolated.
674 void mem_cgroup_del_lru_list(struct page *page, enum lru_list lru)
676 struct page_cgroup *pc;
677 struct mem_cgroup_per_zone *mz;
679 if (mem_cgroup_disabled())
680 return;
681 pc = lookup_page_cgroup(page);
682 /* can happen while we handle swapcache. */
683 if (!TestClearPageCgroupAcctLRU(pc))
684 return;
685 VM_BUG_ON(!pc->mem_cgroup);
687 * We don't check PCG_USED bit. It's cleared when the "page" is finally
688 * removed from global LRU.
690 mz = page_cgroup_zoneinfo(pc);
691 MEM_CGROUP_ZSTAT(mz, lru) -= 1;
692 if (mem_cgroup_is_root(pc->mem_cgroup))
693 return;
694 VM_BUG_ON(list_empty(&pc->lru));
695 list_del_init(&pc->lru);
696 return;
699 void mem_cgroup_del_lru(struct page *page)
701 mem_cgroup_del_lru_list(page, page_lru(page));
704 void mem_cgroup_rotate_lru_list(struct page *page, enum lru_list lru)
706 struct mem_cgroup_per_zone *mz;
707 struct page_cgroup *pc;
709 if (mem_cgroup_disabled())
710 return;
712 pc = lookup_page_cgroup(page);
714 * Used bit is set without atomic ops but after smp_wmb().
715 * For making pc->mem_cgroup visible, insert smp_rmb() here.
717 smp_rmb();
718 /* unused or root page is not rotated. */
719 if (!PageCgroupUsed(pc) || mem_cgroup_is_root(pc->mem_cgroup))
720 return;
721 mz = page_cgroup_zoneinfo(pc);
722 list_move(&pc->lru, &mz->lists[lru]);
725 void mem_cgroup_add_lru_list(struct page *page, enum lru_list lru)
727 struct page_cgroup *pc;
728 struct mem_cgroup_per_zone *mz;
730 if (mem_cgroup_disabled())
731 return;
732 pc = lookup_page_cgroup(page);
733 VM_BUG_ON(PageCgroupAcctLRU(pc));
735 * Used bit is set without atomic ops but after smp_wmb().
736 * For making pc->mem_cgroup visible, insert smp_rmb() here.
738 smp_rmb();
739 if (!PageCgroupUsed(pc))
740 return;
742 mz = page_cgroup_zoneinfo(pc);
743 MEM_CGROUP_ZSTAT(mz, lru) += 1;
744 SetPageCgroupAcctLRU(pc);
745 if (mem_cgroup_is_root(pc->mem_cgroup))
746 return;
747 list_add(&pc->lru, &mz->lists[lru]);
751 * At handling SwapCache, pc->mem_cgroup may be changed while it's linked to
752 * lru because the page may.be reused after it's fully uncharged (because of
753 * SwapCache behavior).To handle that, unlink page_cgroup from LRU when charge
754 * it again. This function is only used to charge SwapCache. It's done under
755 * lock_page and expected that zone->lru_lock is never held.
757 static void mem_cgroup_lru_del_before_commit_swapcache(struct page *page)
759 unsigned long flags;
760 struct zone *zone = page_zone(page);
761 struct page_cgroup *pc = lookup_page_cgroup(page);
763 spin_lock_irqsave(&zone->lru_lock, flags);
765 * Forget old LRU when this page_cgroup is *not* used. This Used bit
766 * is guarded by lock_page() because the page is SwapCache.
768 if (!PageCgroupUsed(pc))
769 mem_cgroup_del_lru_list(page, page_lru(page));
770 spin_unlock_irqrestore(&zone->lru_lock, flags);
773 static void mem_cgroup_lru_add_after_commit_swapcache(struct page *page)
775 unsigned long flags;
776 struct zone *zone = page_zone(page);
777 struct page_cgroup *pc = lookup_page_cgroup(page);
779 spin_lock_irqsave(&zone->lru_lock, flags);
780 /* link when the page is linked to LRU but page_cgroup isn't */
781 if (PageLRU(page) && !PageCgroupAcctLRU(pc))
782 mem_cgroup_add_lru_list(page, page_lru(page));
783 spin_unlock_irqrestore(&zone->lru_lock, flags);
787 void mem_cgroup_move_lists(struct page *page,
788 enum lru_list from, enum lru_list to)
790 if (mem_cgroup_disabled())
791 return;
792 mem_cgroup_del_lru_list(page, from);
793 mem_cgroup_add_lru_list(page, to);
796 int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem)
798 int ret;
799 struct mem_cgroup *curr = NULL;
801 task_lock(task);
802 rcu_read_lock();
803 curr = try_get_mem_cgroup_from_mm(task->mm);
804 rcu_read_unlock();
805 task_unlock(task);
806 if (!curr)
807 return 0;
809 * We should check use_hierarchy of "mem" not "curr". Because checking
810 * use_hierarchy of "curr" here make this function true if hierarchy is
811 * enabled in "curr" and "curr" is a child of "mem" in *cgroup*
812 * hierarchy(even if use_hierarchy is disabled in "mem").
814 if (mem->use_hierarchy)
815 ret = css_is_ancestor(&curr->css, &mem->css);
816 else
817 ret = (curr == mem);
818 css_put(&curr->css);
819 return ret;
823 * prev_priority control...this will be used in memory reclaim path.
825 int mem_cgroup_get_reclaim_priority(struct mem_cgroup *mem)
827 int prev_priority;
829 spin_lock(&mem->reclaim_param_lock);
830 prev_priority = mem->prev_priority;
831 spin_unlock(&mem->reclaim_param_lock);
833 return prev_priority;
836 void mem_cgroup_note_reclaim_priority(struct mem_cgroup *mem, int priority)
838 spin_lock(&mem->reclaim_param_lock);
839 if (priority < mem->prev_priority)
840 mem->prev_priority = priority;
841 spin_unlock(&mem->reclaim_param_lock);
844 void mem_cgroup_record_reclaim_priority(struct mem_cgroup *mem, int priority)
846 spin_lock(&mem->reclaim_param_lock);
847 mem->prev_priority = priority;
848 spin_unlock(&mem->reclaim_param_lock);
851 static int calc_inactive_ratio(struct mem_cgroup *memcg, unsigned long *present_pages)
853 unsigned long active;
854 unsigned long inactive;
855 unsigned long gb;
856 unsigned long inactive_ratio;
858 inactive = mem_cgroup_get_local_zonestat(memcg, LRU_INACTIVE_ANON);
859 active = mem_cgroup_get_local_zonestat(memcg, LRU_ACTIVE_ANON);
861 gb = (inactive + active) >> (30 - PAGE_SHIFT);
862 if (gb)
863 inactive_ratio = int_sqrt(10 * gb);
864 else
865 inactive_ratio = 1;
867 if (present_pages) {
868 present_pages[0] = inactive;
869 present_pages[1] = active;
872 return inactive_ratio;
875 int mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg)
877 unsigned long active;
878 unsigned long inactive;
879 unsigned long present_pages[2];
880 unsigned long inactive_ratio;
882 inactive_ratio = calc_inactive_ratio(memcg, present_pages);
884 inactive = present_pages[0];
885 active = present_pages[1];
887 if (inactive * inactive_ratio < active)
888 return 1;
890 return 0;
893 int mem_cgroup_inactive_file_is_low(struct mem_cgroup *memcg)
895 unsigned long active;
896 unsigned long inactive;
898 inactive = mem_cgroup_get_local_zonestat(memcg, LRU_INACTIVE_FILE);
899 active = mem_cgroup_get_local_zonestat(memcg, LRU_ACTIVE_FILE);
901 return (active > inactive);
904 unsigned long mem_cgroup_zone_nr_pages(struct mem_cgroup *memcg,
905 struct zone *zone,
906 enum lru_list lru)
908 int nid = zone->zone_pgdat->node_id;
909 int zid = zone_idx(zone);
910 struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid);
912 return MEM_CGROUP_ZSTAT(mz, lru);
915 struct zone_reclaim_stat *mem_cgroup_get_reclaim_stat(struct mem_cgroup *memcg,
916 struct zone *zone)
918 int nid = zone->zone_pgdat->node_id;
919 int zid = zone_idx(zone);
920 struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid);
922 return &mz->reclaim_stat;
925 struct zone_reclaim_stat *
926 mem_cgroup_get_reclaim_stat_from_page(struct page *page)
928 struct page_cgroup *pc;
929 struct mem_cgroup_per_zone *mz;
931 if (mem_cgroup_disabled())
932 return NULL;
934 pc = lookup_page_cgroup(page);
936 * Used bit is set without atomic ops but after smp_wmb().
937 * For making pc->mem_cgroup visible, insert smp_rmb() here.
939 smp_rmb();
940 if (!PageCgroupUsed(pc))
941 return NULL;
943 mz = page_cgroup_zoneinfo(pc);
944 if (!mz)
945 return NULL;
947 return &mz->reclaim_stat;
950 unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
951 struct list_head *dst,
952 unsigned long *scanned, int order,
953 int mode, struct zone *z,
954 struct mem_cgroup *mem_cont,
955 int active, int file)
957 unsigned long nr_taken = 0;
958 struct page *page;
959 unsigned long scan;
960 LIST_HEAD(pc_list);
961 struct list_head *src;
962 struct page_cgroup *pc, *tmp;
963 int nid = z->zone_pgdat->node_id;
964 int zid = zone_idx(z);
965 struct mem_cgroup_per_zone *mz;
966 int lru = LRU_FILE * file + active;
967 int ret;
969 BUG_ON(!mem_cont);
970 mz = mem_cgroup_zoneinfo(mem_cont, nid, zid);
971 src = &mz->lists[lru];
973 scan = 0;
974 list_for_each_entry_safe_reverse(pc, tmp, src, lru) {
975 if (scan >= nr_to_scan)
976 break;
978 page = pc->page;
979 if (unlikely(!PageCgroupUsed(pc)))
980 continue;
981 if (unlikely(!PageLRU(page)))
982 continue;
984 scan++;
985 ret = __isolate_lru_page(page, mode, file);
986 switch (ret) {
987 case 0:
988 list_move(&page->lru, dst);
989 mem_cgroup_del_lru(page);
990 nr_taken++;
991 break;
992 case -EBUSY:
993 /* we don't affect global LRU but rotate in our LRU */
994 mem_cgroup_rotate_lru_list(page, page_lru(page));
995 break;
996 default:
997 break;
1001 *scanned = scan;
1002 return nr_taken;
1005 #define mem_cgroup_from_res_counter(counter, member) \
1006 container_of(counter, struct mem_cgroup, member)
1008 static bool mem_cgroup_check_under_limit(struct mem_cgroup *mem)
1010 if (do_swap_account) {
1011 if (res_counter_check_under_limit(&mem->res) &&
1012 res_counter_check_under_limit(&mem->memsw))
1013 return true;
1014 } else
1015 if (res_counter_check_under_limit(&mem->res))
1016 return true;
1017 return false;
1020 static unsigned int get_swappiness(struct mem_cgroup *memcg)
1022 struct cgroup *cgrp = memcg->css.cgroup;
1023 unsigned int swappiness;
1025 /* root ? */
1026 if (cgrp->parent == NULL)
1027 return vm_swappiness;
1029 spin_lock(&memcg->reclaim_param_lock);
1030 swappiness = memcg->swappiness;
1031 spin_unlock(&memcg->reclaim_param_lock);
1033 return swappiness;
1036 static int mem_cgroup_count_children_cb(struct mem_cgroup *mem, void *data)
1038 int *val = data;
1039 (*val)++;
1040 return 0;
1044 * mem_cgroup_print_oom_info: Called from OOM with tasklist_lock held in read mode.
1045 * @memcg: The memory cgroup that went over limit
1046 * @p: Task that is going to be killed
1048 * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is
1049 * enabled
1051 void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
1053 struct cgroup *task_cgrp;
1054 struct cgroup *mem_cgrp;
1056 * Need a buffer in BSS, can't rely on allocations. The code relies
1057 * on the assumption that OOM is serialized for memory controller.
1058 * If this assumption is broken, revisit this code.
1060 static char memcg_name[PATH_MAX];
1061 int ret;
1063 if (!memcg || !p)
1064 return;
1067 rcu_read_lock();
1069 mem_cgrp = memcg->css.cgroup;
1070 task_cgrp = task_cgroup(p, mem_cgroup_subsys_id);
1072 ret = cgroup_path(task_cgrp, memcg_name, PATH_MAX);
1073 if (ret < 0) {
1075 * Unfortunately, we are unable to convert to a useful name
1076 * But we'll still print out the usage information
1078 rcu_read_unlock();
1079 goto done;
1081 rcu_read_unlock();
1083 printk(KERN_INFO "Task in %s killed", memcg_name);
1085 rcu_read_lock();
1086 ret = cgroup_path(mem_cgrp, memcg_name, PATH_MAX);
1087 if (ret < 0) {
1088 rcu_read_unlock();
1089 goto done;
1091 rcu_read_unlock();
1094 * Continues from above, so we don't need an KERN_ level
1096 printk(KERN_CONT " as a result of limit of %s\n", memcg_name);
1097 done:
1099 printk(KERN_INFO "memory: usage %llukB, limit %llukB, failcnt %llu\n",
1100 res_counter_read_u64(&memcg->res, RES_USAGE) >> 10,
1101 res_counter_read_u64(&memcg->res, RES_LIMIT) >> 10,
1102 res_counter_read_u64(&memcg->res, RES_FAILCNT));
1103 printk(KERN_INFO "memory+swap: usage %llukB, limit %llukB, "
1104 "failcnt %llu\n",
1105 res_counter_read_u64(&memcg->memsw, RES_USAGE) >> 10,
1106 res_counter_read_u64(&memcg->memsw, RES_LIMIT) >> 10,
1107 res_counter_read_u64(&memcg->memsw, RES_FAILCNT));
1111 * This function returns the number of memcg under hierarchy tree. Returns
1112 * 1(self count) if no children.
1114 static int mem_cgroup_count_children(struct mem_cgroup *mem)
1116 int num = 0;
1117 mem_cgroup_walk_tree(mem, &num, mem_cgroup_count_children_cb);
1118 return num;
1122 * Visit the first child (need not be the first child as per the ordering
1123 * of the cgroup list, since we track last_scanned_child) of @mem and use
1124 * that to reclaim free pages from.
1126 static struct mem_cgroup *
1127 mem_cgroup_select_victim(struct mem_cgroup *root_mem)
1129 struct mem_cgroup *ret = NULL;
1130 struct cgroup_subsys_state *css;
1131 int nextid, found;
1133 if (!root_mem->use_hierarchy) {
1134 css_get(&root_mem->css);
1135 ret = root_mem;
1138 while (!ret) {
1139 rcu_read_lock();
1140 nextid = root_mem->last_scanned_child + 1;
1141 css = css_get_next(&mem_cgroup_subsys, nextid, &root_mem->css,
1142 &found);
1143 if (css && css_tryget(css))
1144 ret = container_of(css, struct mem_cgroup, css);
1146 rcu_read_unlock();
1147 /* Updates scanning parameter */
1148 spin_lock(&root_mem->reclaim_param_lock);
1149 if (!css) {
1150 /* this means start scan from ID:1 */
1151 root_mem->last_scanned_child = 0;
1152 } else
1153 root_mem->last_scanned_child = found;
1154 spin_unlock(&root_mem->reclaim_param_lock);
1157 return ret;
1161 * Scan the hierarchy if needed to reclaim memory. We remember the last child
1162 * we reclaimed from, so that we don't end up penalizing one child extensively
1163 * based on its position in the children list.
1165 * root_mem is the original ancestor that we've been reclaim from.
1167 * We give up and return to the caller when we visit root_mem twice.
1168 * (other groups can be removed while we're walking....)
1170 * If shrink==true, for avoiding to free too much, this returns immedieately.
1172 static int mem_cgroup_hierarchical_reclaim(struct mem_cgroup *root_mem,
1173 struct zone *zone,
1174 gfp_t gfp_mask,
1175 unsigned long reclaim_options)
1177 struct mem_cgroup *victim;
1178 int ret, total = 0;
1179 int loop = 0;
1180 bool noswap = reclaim_options & MEM_CGROUP_RECLAIM_NOSWAP;
1181 bool shrink = reclaim_options & MEM_CGROUP_RECLAIM_SHRINK;
1182 bool check_soft = reclaim_options & MEM_CGROUP_RECLAIM_SOFT;
1183 unsigned long excess = mem_cgroup_get_excess(root_mem);
1185 /* If memsw_is_minimum==1, swap-out is of-no-use. */
1186 if (root_mem->memsw_is_minimum)
1187 noswap = true;
1189 while (1) {
1190 victim = mem_cgroup_select_victim(root_mem);
1191 if (victim == root_mem) {
1192 loop++;
1193 if (loop >= 1)
1194 drain_all_stock_async();
1195 if (loop >= 2) {
1197 * If we have not been able to reclaim
1198 * anything, it might because there are
1199 * no reclaimable pages under this hierarchy
1201 if (!check_soft || !total) {
1202 css_put(&victim->css);
1203 break;
1206 * We want to do more targetted reclaim.
1207 * excess >> 2 is not to excessive so as to
1208 * reclaim too much, nor too less that we keep
1209 * coming back to reclaim from this cgroup
1211 if (total >= (excess >> 2) ||
1212 (loop > MEM_CGROUP_MAX_RECLAIM_LOOPS)) {
1213 css_put(&victim->css);
1214 break;
1218 if (!mem_cgroup_local_usage(victim)) {
1219 /* this cgroup's local usage == 0 */
1220 css_put(&victim->css);
1221 continue;
1223 /* we use swappiness of local cgroup */
1224 if (check_soft)
1225 ret = mem_cgroup_shrink_node_zone(victim, gfp_mask,
1226 noswap, get_swappiness(victim), zone,
1227 zone->zone_pgdat->node_id);
1228 else
1229 ret = try_to_free_mem_cgroup_pages(victim, gfp_mask,
1230 noswap, get_swappiness(victim));
1231 css_put(&victim->css);
1233 * At shrinking usage, we can't check we should stop here or
1234 * reclaim more. It's depends on callers. last_scanned_child
1235 * will work enough for keeping fairness under tree.
1237 if (shrink)
1238 return ret;
1239 total += ret;
1240 if (check_soft) {
1241 if (res_counter_check_under_soft_limit(&root_mem->res))
1242 return total;
1243 } else if (mem_cgroup_check_under_limit(root_mem))
1244 return 1 + total;
1246 return total;
1249 static int mem_cgroup_oom_lock_cb(struct mem_cgroup *mem, void *data)
1251 int *val = (int *)data;
1252 int x;
1254 * Logically, we can stop scanning immediately when we find
1255 * a memcg is already locked. But condidering unlock ops and
1256 * creation/removal of memcg, scan-all is simple operation.
1258 x = atomic_inc_return(&mem->oom_lock);
1259 *val = max(x, *val);
1260 return 0;
1263 * Check OOM-Killer is already running under our hierarchy.
1264 * If someone is running, return false.
1266 static bool mem_cgroup_oom_lock(struct mem_cgroup *mem)
1268 int lock_count = 0;
1270 mem_cgroup_walk_tree(mem, &lock_count, mem_cgroup_oom_lock_cb);
1272 if (lock_count == 1)
1273 return true;
1274 return false;
1277 static int mem_cgroup_oom_unlock_cb(struct mem_cgroup *mem, void *data)
1280 * When a new child is created while the hierarchy is under oom,
1281 * mem_cgroup_oom_lock() may not be called. We have to use
1282 * atomic_add_unless() here.
1284 atomic_add_unless(&mem->oom_lock, -1, 0);
1285 return 0;
1288 static void mem_cgroup_oom_unlock(struct mem_cgroup *mem)
1290 mem_cgroup_walk_tree(mem, NULL, mem_cgroup_oom_unlock_cb);
1293 static DEFINE_MUTEX(memcg_oom_mutex);
1294 static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq);
1297 * try to call OOM killer. returns false if we should exit memory-reclaim loop.
1299 bool mem_cgroup_handle_oom(struct mem_cgroup *mem, gfp_t mask)
1301 DEFINE_WAIT(wait);
1302 bool locked;
1304 /* At first, try to OOM lock hierarchy under mem.*/
1305 mutex_lock(&memcg_oom_mutex);
1306 locked = mem_cgroup_oom_lock(mem);
1308 * Even if signal_pending(), we can't quit charge() loop without
1309 * accounting. So, UNINTERRUPTIBLE is appropriate. But SIGKILL
1310 * under OOM is always welcomed, use TASK_KILLABLE here.
1312 if (!locked)
1313 prepare_to_wait(&memcg_oom_waitq, &wait, TASK_KILLABLE);
1314 mutex_unlock(&memcg_oom_mutex);
1316 if (locked)
1317 mem_cgroup_out_of_memory(mem, mask);
1318 else {
1319 schedule();
1320 finish_wait(&memcg_oom_waitq, &wait);
1322 mutex_lock(&memcg_oom_mutex);
1323 mem_cgroup_oom_unlock(mem);
1325 * Here, we use global waitq .....more fine grained waitq ?
1326 * Assume following hierarchy.
1327 * A/
1328 * 01
1329 * 02
1330 * assume OOM happens both in A and 01 at the same time. Tthey are
1331 * mutually exclusive by lock. (kill in 01 helps A.)
1332 * When we use per memcg waitq, we have to wake up waiters on A and 02
1333 * in addtion to waiters on 01. We use global waitq for avoiding mess.
1334 * It will not be a big problem.
1335 * (And a task may be moved to other groups while it's waiting for OOM.)
1337 wake_up_all(&memcg_oom_waitq);
1338 mutex_unlock(&memcg_oom_mutex);
1340 if (test_thread_flag(TIF_MEMDIE) || fatal_signal_pending(current))
1341 return false;
1342 /* Give chance to dying process */
1343 schedule_timeout(1);
1344 return true;
1348 * Currently used to update mapped file statistics, but the routine can be
1349 * generalized to update other statistics as well.
1351 void mem_cgroup_update_file_mapped(struct page *page, int val)
1353 struct mem_cgroup *mem;
1354 struct page_cgroup *pc;
1356 pc = lookup_page_cgroup(page);
1357 if (unlikely(!pc))
1358 return;
1360 lock_page_cgroup(pc);
1361 mem = pc->mem_cgroup;
1362 if (!mem)
1363 goto done;
1365 if (!PageCgroupUsed(pc))
1366 goto done;
1369 * Preemption is already disabled. We can use __this_cpu_xxx
1371 __this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_FILE_MAPPED], val);
1373 done:
1374 unlock_page_cgroup(pc);
1378 * size of first charge trial. "32" comes from vmscan.c's magic value.
1379 * TODO: maybe necessary to use big numbers in big irons.
1381 #define CHARGE_SIZE (32 * PAGE_SIZE)
1382 struct memcg_stock_pcp {
1383 struct mem_cgroup *cached; /* this never be root cgroup */
1384 int charge;
1385 struct work_struct work;
1387 static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock);
1388 static atomic_t memcg_drain_count;
1391 * Try to consume stocked charge on this cpu. If success, PAGE_SIZE is consumed
1392 * from local stock and true is returned. If the stock is 0 or charges from a
1393 * cgroup which is not current target, returns false. This stock will be
1394 * refilled.
1396 static bool consume_stock(struct mem_cgroup *mem)
1398 struct memcg_stock_pcp *stock;
1399 bool ret = true;
1401 stock = &get_cpu_var(memcg_stock);
1402 if (mem == stock->cached && stock->charge)
1403 stock->charge -= PAGE_SIZE;
1404 else /* need to call res_counter_charge */
1405 ret = false;
1406 put_cpu_var(memcg_stock);
1407 return ret;
1411 * Returns stocks cached in percpu to res_counter and reset cached information.
1413 static void drain_stock(struct memcg_stock_pcp *stock)
1415 struct mem_cgroup *old = stock->cached;
1417 if (stock->charge) {
1418 res_counter_uncharge(&old->res, stock->charge);
1419 if (do_swap_account)
1420 res_counter_uncharge(&old->memsw, stock->charge);
1422 stock->cached = NULL;
1423 stock->charge = 0;
1427 * This must be called under preempt disabled or must be called by
1428 * a thread which is pinned to local cpu.
1430 static void drain_local_stock(struct work_struct *dummy)
1432 struct memcg_stock_pcp *stock = &__get_cpu_var(memcg_stock);
1433 drain_stock(stock);
1437 * Cache charges(val) which is from res_counter, to local per_cpu area.
1438 * This will be consumed by consumt_stock() function, later.
1440 static void refill_stock(struct mem_cgroup *mem, int val)
1442 struct memcg_stock_pcp *stock = &get_cpu_var(memcg_stock);
1444 if (stock->cached != mem) { /* reset if necessary */
1445 drain_stock(stock);
1446 stock->cached = mem;
1448 stock->charge += val;
1449 put_cpu_var(memcg_stock);
1453 * Tries to drain stocked charges in other cpus. This function is asynchronous
1454 * and just put a work per cpu for draining localy on each cpu. Caller can
1455 * expects some charges will be back to res_counter later but cannot wait for
1456 * it.
1458 static void drain_all_stock_async(void)
1460 int cpu;
1461 /* This function is for scheduling "drain" in asynchronous way.
1462 * The result of "drain" is not directly handled by callers. Then,
1463 * if someone is calling drain, we don't have to call drain more.
1464 * Anyway, WORK_STRUCT_PENDING check in queue_work_on() will catch if
1465 * there is a race. We just do loose check here.
1467 if (atomic_read(&memcg_drain_count))
1468 return;
1469 /* Notify other cpus that system-wide "drain" is running */
1470 atomic_inc(&memcg_drain_count);
1471 get_online_cpus();
1472 for_each_online_cpu(cpu) {
1473 struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
1474 schedule_work_on(cpu, &stock->work);
1476 put_online_cpus();
1477 atomic_dec(&memcg_drain_count);
1478 /* We don't wait for flush_work */
1481 /* This is a synchronous drain interface. */
1482 static void drain_all_stock_sync(void)
1484 /* called when force_empty is called */
1485 atomic_inc(&memcg_drain_count);
1486 schedule_on_each_cpu(drain_local_stock);
1487 atomic_dec(&memcg_drain_count);
1490 static int __cpuinit memcg_stock_cpu_callback(struct notifier_block *nb,
1491 unsigned long action,
1492 void *hcpu)
1494 int cpu = (unsigned long)hcpu;
1495 struct memcg_stock_pcp *stock;
1497 if (action != CPU_DEAD)
1498 return NOTIFY_OK;
1499 stock = &per_cpu(memcg_stock, cpu);
1500 drain_stock(stock);
1501 return NOTIFY_OK;
1505 * Unlike exported interface, "oom" parameter is added. if oom==true,
1506 * oom-killer can be invoked.
1508 static int __mem_cgroup_try_charge(struct mm_struct *mm,
1509 gfp_t gfp_mask, struct mem_cgroup **memcg, bool oom)
1511 struct mem_cgroup *mem, *mem_over_limit;
1512 int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
1513 struct res_counter *fail_res;
1514 int csize = CHARGE_SIZE;
1517 * Unlike gloval-vm's OOM-kill, we're not in memory shortage
1518 * in system level. So, allow to go ahead dying process in addition to
1519 * MEMDIE process.
1521 if (unlikely(test_thread_flag(TIF_MEMDIE)
1522 || fatal_signal_pending(current)))
1523 goto bypass;
1526 * We always charge the cgroup the mm_struct belongs to.
1527 * The mm_struct's mem_cgroup changes on task migration if the
1528 * thread group leader migrates. It's possible that mm is not
1529 * set, if so charge the init_mm (happens for pagecache usage).
1531 mem = *memcg;
1532 if (likely(!mem)) {
1533 mem = try_get_mem_cgroup_from_mm(mm);
1534 *memcg = mem;
1535 } else {
1536 css_get(&mem->css);
1538 if (unlikely(!mem))
1539 return 0;
1541 VM_BUG_ON(css_is_removed(&mem->css));
1542 if (mem_cgroup_is_root(mem))
1543 goto done;
1545 while (1) {
1546 int ret = 0;
1547 unsigned long flags = 0;
1549 if (consume_stock(mem))
1550 goto done;
1552 ret = res_counter_charge(&mem->res, csize, &fail_res);
1553 if (likely(!ret)) {
1554 if (!do_swap_account)
1555 break;
1556 ret = res_counter_charge(&mem->memsw, csize, &fail_res);
1557 if (likely(!ret))
1558 break;
1559 /* mem+swap counter fails */
1560 res_counter_uncharge(&mem->res, csize);
1561 flags |= MEM_CGROUP_RECLAIM_NOSWAP;
1562 mem_over_limit = mem_cgroup_from_res_counter(fail_res,
1563 memsw);
1564 } else
1565 /* mem counter fails */
1566 mem_over_limit = mem_cgroup_from_res_counter(fail_res,
1567 res);
1569 /* reduce request size and retry */
1570 if (csize > PAGE_SIZE) {
1571 csize = PAGE_SIZE;
1572 continue;
1574 if (!(gfp_mask & __GFP_WAIT))
1575 goto nomem;
1577 ret = mem_cgroup_hierarchical_reclaim(mem_over_limit, NULL,
1578 gfp_mask, flags);
1579 if (ret)
1580 continue;
1583 * try_to_free_mem_cgroup_pages() might not give us a full
1584 * picture of reclaim. Some pages are reclaimed and might be
1585 * moved to swap cache or just unmapped from the cgroup.
1586 * Check the limit again to see if the reclaim reduced the
1587 * current usage of the cgroup before giving up
1590 if (mem_cgroup_check_under_limit(mem_over_limit))
1591 continue;
1593 /* try to avoid oom while someone is moving charge */
1594 if (mc.moving_task && current != mc.moving_task) {
1595 struct mem_cgroup *from, *to;
1596 bool do_continue = false;
1598 * There is a small race that "from" or "to" can be
1599 * freed by rmdir, so we use css_tryget().
1601 rcu_read_lock();
1602 from = mc.from;
1603 to = mc.to;
1604 if (from && css_tryget(&from->css)) {
1605 if (mem_over_limit->use_hierarchy)
1606 do_continue = css_is_ancestor(
1607 &from->css,
1608 &mem_over_limit->css);
1609 else
1610 do_continue = (from == mem_over_limit);
1611 css_put(&from->css);
1613 if (!do_continue && to && css_tryget(&to->css)) {
1614 if (mem_over_limit->use_hierarchy)
1615 do_continue = css_is_ancestor(
1616 &to->css,
1617 &mem_over_limit->css);
1618 else
1619 do_continue = (to == mem_over_limit);
1620 css_put(&to->css);
1622 rcu_read_unlock();
1623 if (do_continue) {
1624 DEFINE_WAIT(wait);
1625 prepare_to_wait(&mc.waitq, &wait,
1626 TASK_INTERRUPTIBLE);
1627 /* moving charge context might have finished. */
1628 if (mc.moving_task)
1629 schedule();
1630 finish_wait(&mc.waitq, &wait);
1631 continue;
1635 if (!nr_retries--) {
1636 if (!oom)
1637 goto nomem;
1638 if (mem_cgroup_handle_oom(mem_over_limit, gfp_mask)) {
1639 nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
1640 continue;
1642 /* When we reach here, current task is dying .*/
1643 css_put(&mem->css);
1644 goto bypass;
1647 if (csize > PAGE_SIZE)
1648 refill_stock(mem, csize - PAGE_SIZE);
1649 done:
1650 return 0;
1651 nomem:
1652 css_put(&mem->css);
1653 return -ENOMEM;
1654 bypass:
1655 *memcg = NULL;
1656 return 0;
1660 * Somemtimes we have to undo a charge we got by try_charge().
1661 * This function is for that and do uncharge, put css's refcnt.
1662 * gotten by try_charge().
1664 static void __mem_cgroup_cancel_charge(struct mem_cgroup *mem,
1665 unsigned long count)
1667 if (!mem_cgroup_is_root(mem)) {
1668 res_counter_uncharge(&mem->res, PAGE_SIZE * count);
1669 if (do_swap_account)
1670 res_counter_uncharge(&mem->memsw, PAGE_SIZE * count);
1671 VM_BUG_ON(test_bit(CSS_ROOT, &mem->css.flags));
1672 WARN_ON_ONCE(count > INT_MAX);
1673 __css_put(&mem->css, (int)count);
1675 /* we don't need css_put for root */
1678 static void mem_cgroup_cancel_charge(struct mem_cgroup *mem)
1680 __mem_cgroup_cancel_charge(mem, 1);
1684 * A helper function to get mem_cgroup from ID. must be called under
1685 * rcu_read_lock(). The caller must check css_is_removed() or some if
1686 * it's concern. (dropping refcnt from swap can be called against removed
1687 * memcg.)
1689 static struct mem_cgroup *mem_cgroup_lookup(unsigned short id)
1691 struct cgroup_subsys_state *css;
1693 /* ID 0 is unused ID */
1694 if (!id)
1695 return NULL;
1696 css = css_lookup(&mem_cgroup_subsys, id);
1697 if (!css)
1698 return NULL;
1699 return container_of(css, struct mem_cgroup, css);
1702 struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page)
1704 struct mem_cgroup *mem = NULL;
1705 struct page_cgroup *pc;
1706 unsigned short id;
1707 swp_entry_t ent;
1709 VM_BUG_ON(!PageLocked(page));
1711 pc = lookup_page_cgroup(page);
1712 lock_page_cgroup(pc);
1713 if (PageCgroupUsed(pc)) {
1714 mem = pc->mem_cgroup;
1715 if (mem && !css_tryget(&mem->css))
1716 mem = NULL;
1717 } else if (PageSwapCache(page)) {
1718 ent.val = page_private(page);
1719 id = lookup_swap_cgroup(ent);
1720 rcu_read_lock();
1721 mem = mem_cgroup_lookup(id);
1722 if (mem && !css_tryget(&mem->css))
1723 mem = NULL;
1724 rcu_read_unlock();
1726 unlock_page_cgroup(pc);
1727 return mem;
1731 * commit a charge got by __mem_cgroup_try_charge() and makes page_cgroup to be
1732 * USED state. If already USED, uncharge and return.
1735 static void __mem_cgroup_commit_charge(struct mem_cgroup *mem,
1736 struct page_cgroup *pc,
1737 enum charge_type ctype)
1739 /* try_charge() can return NULL to *memcg, taking care of it. */
1740 if (!mem)
1741 return;
1743 lock_page_cgroup(pc);
1744 if (unlikely(PageCgroupUsed(pc))) {
1745 unlock_page_cgroup(pc);
1746 mem_cgroup_cancel_charge(mem);
1747 return;
1750 pc->mem_cgroup = mem;
1752 * We access a page_cgroup asynchronously without lock_page_cgroup().
1753 * Especially when a page_cgroup is taken from a page, pc->mem_cgroup
1754 * is accessed after testing USED bit. To make pc->mem_cgroup visible
1755 * before USED bit, we need memory barrier here.
1756 * See mem_cgroup_add_lru_list(), etc.
1758 smp_wmb();
1759 switch (ctype) {
1760 case MEM_CGROUP_CHARGE_TYPE_CACHE:
1761 case MEM_CGROUP_CHARGE_TYPE_SHMEM:
1762 SetPageCgroupCache(pc);
1763 SetPageCgroupUsed(pc);
1764 break;
1765 case MEM_CGROUP_CHARGE_TYPE_MAPPED:
1766 ClearPageCgroupCache(pc);
1767 SetPageCgroupUsed(pc);
1768 break;
1769 default:
1770 break;
1773 mem_cgroup_charge_statistics(mem, pc, true);
1775 unlock_page_cgroup(pc);
1777 * "charge_statistics" updated event counter. Then, check it.
1778 * Insert ancestor (and ancestor's ancestors), to softlimit RB-tree.
1779 * if they exceeds softlimit.
1781 memcg_check_events(mem, pc->page);
1785 * __mem_cgroup_move_account - move account of the page
1786 * @pc: page_cgroup of the page.
1787 * @from: mem_cgroup which the page is moved from.
1788 * @to: mem_cgroup which the page is moved to. @from != @to.
1789 * @uncharge: whether we should call uncharge and css_put against @from.
1791 * The caller must confirm following.
1792 * - page is not on LRU (isolate_page() is useful.)
1793 * - the pc is locked, used, and ->mem_cgroup points to @from.
1795 * This function doesn't do "charge" nor css_get to new cgroup. It should be
1796 * done by a caller(__mem_cgroup_try_charge would be usefull). If @uncharge is
1797 * true, this function does "uncharge" from old cgroup, but it doesn't if
1798 * @uncharge is false, so a caller should do "uncharge".
1801 static void __mem_cgroup_move_account(struct page_cgroup *pc,
1802 struct mem_cgroup *from, struct mem_cgroup *to, bool uncharge)
1804 struct page *page;
1806 VM_BUG_ON(from == to);
1807 VM_BUG_ON(PageLRU(pc->page));
1808 VM_BUG_ON(!PageCgroupLocked(pc));
1809 VM_BUG_ON(!PageCgroupUsed(pc));
1810 VM_BUG_ON(pc->mem_cgroup != from);
1812 page = pc->page;
1813 if (page_mapped(page) && !PageAnon(page)) {
1814 /* Update mapped_file data for mem_cgroup */
1815 preempt_disable();
1816 __this_cpu_dec(from->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]);
1817 __this_cpu_inc(to->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]);
1818 preempt_enable();
1820 mem_cgroup_charge_statistics(from, pc, false);
1821 if (uncharge)
1822 /* This is not "cancel", but cancel_charge does all we need. */
1823 mem_cgroup_cancel_charge(from);
1825 /* caller should have done css_get */
1826 pc->mem_cgroup = to;
1827 mem_cgroup_charge_statistics(to, pc, true);
1829 * We charges against "to" which may not have any tasks. Then, "to"
1830 * can be under rmdir(). But in current implementation, caller of
1831 * this function is just force_empty() and move charge, so it's
1832 * garanteed that "to" is never removed. So, we don't check rmdir
1833 * status here.
1838 * check whether the @pc is valid for moving account and call
1839 * __mem_cgroup_move_account()
1841 static int mem_cgroup_move_account(struct page_cgroup *pc,
1842 struct mem_cgroup *from, struct mem_cgroup *to, bool uncharge)
1844 int ret = -EINVAL;
1845 lock_page_cgroup(pc);
1846 if (PageCgroupUsed(pc) && pc->mem_cgroup == from) {
1847 __mem_cgroup_move_account(pc, from, to, uncharge);
1848 ret = 0;
1850 unlock_page_cgroup(pc);
1852 * check events
1854 memcg_check_events(to, pc->page);
1855 memcg_check_events(from, pc->page);
1856 return ret;
1860 * move charges to its parent.
1863 static int mem_cgroup_move_parent(struct page_cgroup *pc,
1864 struct mem_cgroup *child,
1865 gfp_t gfp_mask)
1867 struct page *page = pc->page;
1868 struct cgroup *cg = child->css.cgroup;
1869 struct cgroup *pcg = cg->parent;
1870 struct mem_cgroup *parent;
1871 int ret;
1873 /* Is ROOT ? */
1874 if (!pcg)
1875 return -EINVAL;
1877 ret = -EBUSY;
1878 if (!get_page_unless_zero(page))
1879 goto out;
1880 if (isolate_lru_page(page))
1881 goto put;
1883 parent = mem_cgroup_from_cont(pcg);
1884 ret = __mem_cgroup_try_charge(NULL, gfp_mask, &parent, false);
1885 if (ret || !parent)
1886 goto put_back;
1888 ret = mem_cgroup_move_account(pc, child, parent, true);
1889 if (ret)
1890 mem_cgroup_cancel_charge(parent);
1891 put_back:
1892 putback_lru_page(page);
1893 put:
1894 put_page(page);
1895 out:
1896 return ret;
1900 * Charge the memory controller for page usage.
1901 * Return
1902 * 0 if the charge was successful
1903 * < 0 if the cgroup is over its limit
1905 static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm,
1906 gfp_t gfp_mask, enum charge_type ctype,
1907 struct mem_cgroup *memcg)
1909 struct mem_cgroup *mem;
1910 struct page_cgroup *pc;
1911 int ret;
1913 pc = lookup_page_cgroup(page);
1914 /* can happen at boot */
1915 if (unlikely(!pc))
1916 return 0;
1917 prefetchw(pc);
1919 mem = memcg;
1920 ret = __mem_cgroup_try_charge(mm, gfp_mask, &mem, true);
1921 if (ret || !mem)
1922 return ret;
1924 __mem_cgroup_commit_charge(mem, pc, ctype);
1925 return 0;
1928 int mem_cgroup_newpage_charge(struct page *page,
1929 struct mm_struct *mm, gfp_t gfp_mask)
1931 if (mem_cgroup_disabled())
1932 return 0;
1933 if (PageCompound(page))
1934 return 0;
1936 * If already mapped, we don't have to account.
1937 * If page cache, page->mapping has address_space.
1938 * But page->mapping may have out-of-use anon_vma pointer,
1939 * detecit it by PageAnon() check. newly-mapped-anon's page->mapping
1940 * is NULL.
1942 if (page_mapped(page) || (page->mapping && !PageAnon(page)))
1943 return 0;
1944 if (unlikely(!mm))
1945 mm = &init_mm;
1946 return mem_cgroup_charge_common(page, mm, gfp_mask,
1947 MEM_CGROUP_CHARGE_TYPE_MAPPED, NULL);
1950 static void
1951 __mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr,
1952 enum charge_type ctype);
1954 int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
1955 gfp_t gfp_mask)
1957 struct mem_cgroup *mem = NULL;
1958 int ret;
1960 if (mem_cgroup_disabled())
1961 return 0;
1962 if (PageCompound(page))
1963 return 0;
1965 * Corner case handling. This is called from add_to_page_cache()
1966 * in usual. But some FS (shmem) precharges this page before calling it
1967 * and call add_to_page_cache() with GFP_NOWAIT.
1969 * For GFP_NOWAIT case, the page may be pre-charged before calling
1970 * add_to_page_cache(). (See shmem.c) check it here and avoid to call
1971 * charge twice. (It works but has to pay a bit larger cost.)
1972 * And when the page is SwapCache, it should take swap information
1973 * into account. This is under lock_page() now.
1975 if (!(gfp_mask & __GFP_WAIT)) {
1976 struct page_cgroup *pc;
1979 pc = lookup_page_cgroup(page);
1980 if (!pc)
1981 return 0;
1982 lock_page_cgroup(pc);
1983 if (PageCgroupUsed(pc)) {
1984 unlock_page_cgroup(pc);
1985 return 0;
1987 unlock_page_cgroup(pc);
1990 if (unlikely(!mm && !mem))
1991 mm = &init_mm;
1993 if (page_is_file_cache(page))
1994 return mem_cgroup_charge_common(page, mm, gfp_mask,
1995 MEM_CGROUP_CHARGE_TYPE_CACHE, NULL);
1997 /* shmem */
1998 if (PageSwapCache(page)) {
1999 ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &mem);
2000 if (!ret)
2001 __mem_cgroup_commit_charge_swapin(page, mem,
2002 MEM_CGROUP_CHARGE_TYPE_SHMEM);
2003 } else
2004 ret = mem_cgroup_charge_common(page, mm, gfp_mask,
2005 MEM_CGROUP_CHARGE_TYPE_SHMEM, mem);
2007 return ret;
2011 * While swap-in, try_charge -> commit or cancel, the page is locked.
2012 * And when try_charge() successfully returns, one refcnt to memcg without
2013 * struct page_cgroup is acquired. This refcnt will be consumed by
2014 * "commit()" or removed by "cancel()"
2016 int mem_cgroup_try_charge_swapin(struct mm_struct *mm,
2017 struct page *page,
2018 gfp_t mask, struct mem_cgroup **ptr)
2020 struct mem_cgroup *mem;
2021 int ret;
2023 if (mem_cgroup_disabled())
2024 return 0;
2026 if (!do_swap_account)
2027 goto charge_cur_mm;
2029 * A racing thread's fault, or swapoff, may have already updated
2030 * the pte, and even removed page from swap cache: in those cases
2031 * do_swap_page()'s pte_same() test will fail; but there's also a
2032 * KSM case which does need to charge the page.
2034 if (!PageSwapCache(page))
2035 goto charge_cur_mm;
2036 mem = try_get_mem_cgroup_from_page(page);
2037 if (!mem)
2038 goto charge_cur_mm;
2039 *ptr = mem;
2040 ret = __mem_cgroup_try_charge(NULL, mask, ptr, true);
2041 /* drop extra refcnt from tryget */
2042 css_put(&mem->css);
2043 return ret;
2044 charge_cur_mm:
2045 if (unlikely(!mm))
2046 mm = &init_mm;
2047 return __mem_cgroup_try_charge(mm, mask, ptr, true);
2050 static void
2051 __mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr,
2052 enum charge_type ctype)
2054 struct page_cgroup *pc;
2056 if (mem_cgroup_disabled())
2057 return;
2058 if (!ptr)
2059 return;
2060 cgroup_exclude_rmdir(&ptr->css);
2061 pc = lookup_page_cgroup(page);
2062 mem_cgroup_lru_del_before_commit_swapcache(page);
2063 __mem_cgroup_commit_charge(ptr, pc, ctype);
2064 mem_cgroup_lru_add_after_commit_swapcache(page);
2066 * Now swap is on-memory. This means this page may be
2067 * counted both as mem and swap....double count.
2068 * Fix it by uncharging from memsw. Basically, this SwapCache is stable
2069 * under lock_page(). But in do_swap_page()::memory.c, reuse_swap_page()
2070 * may call delete_from_swap_cache() before reach here.
2072 if (do_swap_account && PageSwapCache(page)) {
2073 swp_entry_t ent = {.val = page_private(page)};
2074 unsigned short id;
2075 struct mem_cgroup *memcg;
2077 id = swap_cgroup_record(ent, 0);
2078 rcu_read_lock();
2079 memcg = mem_cgroup_lookup(id);
2080 if (memcg) {
2082 * This recorded memcg can be obsolete one. So, avoid
2083 * calling css_tryget
2085 if (!mem_cgroup_is_root(memcg))
2086 res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
2087 mem_cgroup_swap_statistics(memcg, false);
2088 mem_cgroup_put(memcg);
2090 rcu_read_unlock();
2093 * At swapin, we may charge account against cgroup which has no tasks.
2094 * So, rmdir()->pre_destroy() can be called while we do this charge.
2095 * In that case, we need to call pre_destroy() again. check it here.
2097 cgroup_release_and_wakeup_rmdir(&ptr->css);
2100 void mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr)
2102 __mem_cgroup_commit_charge_swapin(page, ptr,
2103 MEM_CGROUP_CHARGE_TYPE_MAPPED);
2106 void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *mem)
2108 if (mem_cgroup_disabled())
2109 return;
2110 if (!mem)
2111 return;
2112 mem_cgroup_cancel_charge(mem);
2115 static void
2116 __do_uncharge(struct mem_cgroup *mem, const enum charge_type ctype)
2118 struct memcg_batch_info *batch = NULL;
2119 bool uncharge_memsw = true;
2120 /* If swapout, usage of swap doesn't decrease */
2121 if (!do_swap_account || ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT)
2122 uncharge_memsw = false;
2124 * do_batch > 0 when unmapping pages or inode invalidate/truncate.
2125 * In those cases, all pages freed continously can be expected to be in
2126 * the same cgroup and we have chance to coalesce uncharges.
2127 * But we do uncharge one by one if this is killed by OOM(TIF_MEMDIE)
2128 * because we want to do uncharge as soon as possible.
2130 if (!current->memcg_batch.do_batch || test_thread_flag(TIF_MEMDIE))
2131 goto direct_uncharge;
2133 batch = &current->memcg_batch;
2135 * In usual, we do css_get() when we remember memcg pointer.
2136 * But in this case, we keep res->usage until end of a series of
2137 * uncharges. Then, it's ok to ignore memcg's refcnt.
2139 if (!batch->memcg)
2140 batch->memcg = mem;
2142 * In typical case, batch->memcg == mem. This means we can
2143 * merge a series of uncharges to an uncharge of res_counter.
2144 * If not, we uncharge res_counter ony by one.
2146 if (batch->memcg != mem)
2147 goto direct_uncharge;
2148 /* remember freed charge and uncharge it later */
2149 batch->bytes += PAGE_SIZE;
2150 if (uncharge_memsw)
2151 batch->memsw_bytes += PAGE_SIZE;
2152 return;
2153 direct_uncharge:
2154 res_counter_uncharge(&mem->res, PAGE_SIZE);
2155 if (uncharge_memsw)
2156 res_counter_uncharge(&mem->memsw, PAGE_SIZE);
2157 return;
2161 * uncharge if !page_mapped(page)
2163 static struct mem_cgroup *
2164 __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
2166 struct page_cgroup *pc;
2167 struct mem_cgroup *mem = NULL;
2168 struct mem_cgroup_per_zone *mz;
2170 if (mem_cgroup_disabled())
2171 return NULL;
2173 if (PageSwapCache(page))
2174 return NULL;
2177 * Check if our page_cgroup is valid
2179 pc = lookup_page_cgroup(page);
2180 if (unlikely(!pc || !PageCgroupUsed(pc)))
2181 return NULL;
2183 lock_page_cgroup(pc);
2185 mem = pc->mem_cgroup;
2187 if (!PageCgroupUsed(pc))
2188 goto unlock_out;
2190 switch (ctype) {
2191 case MEM_CGROUP_CHARGE_TYPE_MAPPED:
2192 case MEM_CGROUP_CHARGE_TYPE_DROP:
2193 if (page_mapped(page))
2194 goto unlock_out;
2195 break;
2196 case MEM_CGROUP_CHARGE_TYPE_SWAPOUT:
2197 if (!PageAnon(page)) { /* Shared memory */
2198 if (page->mapping && !page_is_file_cache(page))
2199 goto unlock_out;
2200 } else if (page_mapped(page)) /* Anon */
2201 goto unlock_out;
2202 break;
2203 default:
2204 break;
2207 if (!mem_cgroup_is_root(mem))
2208 __do_uncharge(mem, ctype);
2209 if (ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT)
2210 mem_cgroup_swap_statistics(mem, true);
2211 mem_cgroup_charge_statistics(mem, pc, false);
2213 ClearPageCgroupUsed(pc);
2215 * pc->mem_cgroup is not cleared here. It will be accessed when it's
2216 * freed from LRU. This is safe because uncharged page is expected not
2217 * to be reused (freed soon). Exception is SwapCache, it's handled by
2218 * special functions.
2221 mz = page_cgroup_zoneinfo(pc);
2222 unlock_page_cgroup(pc);
2224 memcg_check_events(mem, page);
2225 /* at swapout, this memcg will be accessed to record to swap */
2226 if (ctype != MEM_CGROUP_CHARGE_TYPE_SWAPOUT)
2227 css_put(&mem->css);
2229 return mem;
2231 unlock_out:
2232 unlock_page_cgroup(pc);
2233 return NULL;
2236 void mem_cgroup_uncharge_page(struct page *page)
2238 /* early check. */
2239 if (page_mapped(page))
2240 return;
2241 if (page->mapping && !PageAnon(page))
2242 return;
2243 __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_MAPPED);
2246 void mem_cgroup_uncharge_cache_page(struct page *page)
2248 VM_BUG_ON(page_mapped(page));
2249 VM_BUG_ON(page->mapping);
2250 __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE);
2254 * Batch_start/batch_end is called in unmap_page_range/invlidate/trucate.
2255 * In that cases, pages are freed continuously and we can expect pages
2256 * are in the same memcg. All these calls itself limits the number of
2257 * pages freed at once, then uncharge_start/end() is called properly.
2258 * This may be called prural(2) times in a context,
2261 void mem_cgroup_uncharge_start(void)
2263 current->memcg_batch.do_batch++;
2264 /* We can do nest. */
2265 if (current->memcg_batch.do_batch == 1) {
2266 current->memcg_batch.memcg = NULL;
2267 current->memcg_batch.bytes = 0;
2268 current->memcg_batch.memsw_bytes = 0;
2272 void mem_cgroup_uncharge_end(void)
2274 struct memcg_batch_info *batch = &current->memcg_batch;
2276 if (!batch->do_batch)
2277 return;
2279 batch->do_batch--;
2280 if (batch->do_batch) /* If stacked, do nothing. */
2281 return;
2283 if (!batch->memcg)
2284 return;
2286 * This "batch->memcg" is valid without any css_get/put etc...
2287 * bacause we hide charges behind us.
2289 if (batch->bytes)
2290 res_counter_uncharge(&batch->memcg->res, batch->bytes);
2291 if (batch->memsw_bytes)
2292 res_counter_uncharge(&batch->memcg->memsw, batch->memsw_bytes);
2293 /* forget this pointer (for sanity check) */
2294 batch->memcg = NULL;
2297 #ifdef CONFIG_SWAP
2299 * called after __delete_from_swap_cache() and drop "page" account.
2300 * memcg information is recorded to swap_cgroup of "ent"
2302 void
2303 mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout)
2305 struct mem_cgroup *memcg;
2306 int ctype = MEM_CGROUP_CHARGE_TYPE_SWAPOUT;
2308 if (!swapout) /* this was a swap cache but the swap is unused ! */
2309 ctype = MEM_CGROUP_CHARGE_TYPE_DROP;
2311 memcg = __mem_cgroup_uncharge_common(page, ctype);
2313 /* record memcg information */
2314 if (do_swap_account && swapout && memcg) {
2315 swap_cgroup_record(ent, css_id(&memcg->css));
2316 mem_cgroup_get(memcg);
2318 if (swapout && memcg)
2319 css_put(&memcg->css);
2321 #endif
2323 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
2325 * called from swap_entry_free(). remove record in swap_cgroup and
2326 * uncharge "memsw" account.
2328 void mem_cgroup_uncharge_swap(swp_entry_t ent)
2330 struct mem_cgroup *memcg;
2331 unsigned short id;
2333 if (!do_swap_account)
2334 return;
2336 id = swap_cgroup_record(ent, 0);
2337 rcu_read_lock();
2338 memcg = mem_cgroup_lookup(id);
2339 if (memcg) {
2341 * We uncharge this because swap is freed.
2342 * This memcg can be obsolete one. We avoid calling css_tryget
2344 if (!mem_cgroup_is_root(memcg))
2345 res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
2346 mem_cgroup_swap_statistics(memcg, false);
2347 mem_cgroup_put(memcg);
2349 rcu_read_unlock();
2353 * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record.
2354 * @entry: swap entry to be moved
2355 * @from: mem_cgroup which the entry is moved from
2356 * @to: mem_cgroup which the entry is moved to
2357 * @need_fixup: whether we should fixup res_counters and refcounts.
2359 * It succeeds only when the swap_cgroup's record for this entry is the same
2360 * as the mem_cgroup's id of @from.
2362 * Returns 0 on success, -EINVAL on failure.
2364 * The caller must have charged to @to, IOW, called res_counter_charge() about
2365 * both res and memsw, and called css_get().
2367 static int mem_cgroup_move_swap_account(swp_entry_t entry,
2368 struct mem_cgroup *from, struct mem_cgroup *to, bool need_fixup)
2370 unsigned short old_id, new_id;
2372 old_id = css_id(&from->css);
2373 new_id = css_id(&to->css);
2375 if (swap_cgroup_cmpxchg(entry, old_id, new_id) == old_id) {
2376 mem_cgroup_swap_statistics(from, false);
2377 mem_cgroup_swap_statistics(to, true);
2379 * This function is only called from task migration context now.
2380 * It postpones res_counter and refcount handling till the end
2381 * of task migration(mem_cgroup_clear_mc()) for performance
2382 * improvement. But we cannot postpone mem_cgroup_get(to)
2383 * because if the process that has been moved to @to does
2384 * swap-in, the refcount of @to might be decreased to 0.
2386 mem_cgroup_get(to);
2387 if (need_fixup) {
2388 if (!mem_cgroup_is_root(from))
2389 res_counter_uncharge(&from->memsw, PAGE_SIZE);
2390 mem_cgroup_put(from);
2392 * we charged both to->res and to->memsw, so we should
2393 * uncharge to->res.
2395 if (!mem_cgroup_is_root(to))
2396 res_counter_uncharge(&to->res, PAGE_SIZE);
2397 css_put(&to->css);
2399 return 0;
2401 return -EINVAL;
2403 #else
2404 static inline int mem_cgroup_move_swap_account(swp_entry_t entry,
2405 struct mem_cgroup *from, struct mem_cgroup *to, bool need_fixup)
2407 return -EINVAL;
2409 #endif
2412 * Before starting migration, account PAGE_SIZE to mem_cgroup that the old
2413 * page belongs to.
2415 int mem_cgroup_prepare_migration(struct page *page, struct mem_cgroup **ptr)
2417 struct page_cgroup *pc;
2418 struct mem_cgroup *mem = NULL;
2419 int ret = 0;
2421 if (mem_cgroup_disabled())
2422 return 0;
2424 pc = lookup_page_cgroup(page);
2425 lock_page_cgroup(pc);
2426 if (PageCgroupUsed(pc)) {
2427 mem = pc->mem_cgroup;
2428 css_get(&mem->css);
2430 unlock_page_cgroup(pc);
2432 if (mem) {
2433 ret = __mem_cgroup_try_charge(NULL, GFP_KERNEL, &mem, false);
2434 css_put(&mem->css);
2436 *ptr = mem;
2437 return ret;
2440 /* remove redundant charge if migration failed*/
2441 void mem_cgroup_end_migration(struct mem_cgroup *mem,
2442 struct page *oldpage, struct page *newpage)
2444 struct page *target, *unused;
2445 struct page_cgroup *pc;
2446 enum charge_type ctype;
2448 if (!mem)
2449 return;
2450 cgroup_exclude_rmdir(&mem->css);
2451 /* at migration success, oldpage->mapping is NULL. */
2452 if (oldpage->mapping) {
2453 target = oldpage;
2454 unused = NULL;
2455 } else {
2456 target = newpage;
2457 unused = oldpage;
2460 if (PageAnon(target))
2461 ctype = MEM_CGROUP_CHARGE_TYPE_MAPPED;
2462 else if (page_is_file_cache(target))
2463 ctype = MEM_CGROUP_CHARGE_TYPE_CACHE;
2464 else
2465 ctype = MEM_CGROUP_CHARGE_TYPE_SHMEM;
2467 /* unused page is not on radix-tree now. */
2468 if (unused)
2469 __mem_cgroup_uncharge_common(unused, ctype);
2471 pc = lookup_page_cgroup(target);
2473 * __mem_cgroup_commit_charge() check PCG_USED bit of page_cgroup.
2474 * So, double-counting is effectively avoided.
2476 __mem_cgroup_commit_charge(mem, pc, ctype);
2479 * Both of oldpage and newpage are still under lock_page().
2480 * Then, we don't have to care about race in radix-tree.
2481 * But we have to be careful that this page is unmapped or not.
2483 * There is a case for !page_mapped(). At the start of
2484 * migration, oldpage was mapped. But now, it's zapped.
2485 * But we know *target* page is not freed/reused under us.
2486 * mem_cgroup_uncharge_page() does all necessary checks.
2488 if (ctype == MEM_CGROUP_CHARGE_TYPE_MAPPED)
2489 mem_cgroup_uncharge_page(target);
2491 * At migration, we may charge account against cgroup which has no tasks
2492 * So, rmdir()->pre_destroy() can be called while we do this charge.
2493 * In that case, we need to call pre_destroy() again. check it here.
2495 cgroup_release_and_wakeup_rmdir(&mem->css);
2499 * A call to try to shrink memory usage on charge failure at shmem's swapin.
2500 * Calling hierarchical_reclaim is not enough because we should update
2501 * last_oom_jiffies to prevent pagefault_out_of_memory from invoking global OOM.
2502 * Moreover considering hierarchy, we should reclaim from the mem_over_limit,
2503 * not from the memcg which this page would be charged to.
2504 * try_charge_swapin does all of these works properly.
2506 int mem_cgroup_shmem_charge_fallback(struct page *page,
2507 struct mm_struct *mm,
2508 gfp_t gfp_mask)
2510 struct mem_cgroup *mem = NULL;
2511 int ret;
2513 if (mem_cgroup_disabled())
2514 return 0;
2516 ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &mem);
2517 if (!ret)
2518 mem_cgroup_cancel_charge_swapin(mem); /* it does !mem check */
2520 return ret;
2523 static DEFINE_MUTEX(set_limit_mutex);
2525 static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
2526 unsigned long long val)
2528 int retry_count;
2529 u64 memswlimit;
2530 int ret = 0;
2531 int children = mem_cgroup_count_children(memcg);
2532 u64 curusage, oldusage;
2535 * For keeping hierarchical_reclaim simple, how long we should retry
2536 * is depends on callers. We set our retry-count to be function
2537 * of # of children which we should visit in this loop.
2539 retry_count = MEM_CGROUP_RECLAIM_RETRIES * children;
2541 oldusage = res_counter_read_u64(&memcg->res, RES_USAGE);
2543 while (retry_count) {
2544 if (signal_pending(current)) {
2545 ret = -EINTR;
2546 break;
2549 * Rather than hide all in some function, I do this in
2550 * open coded manner. You see what this really does.
2551 * We have to guarantee mem->res.limit < mem->memsw.limit.
2553 mutex_lock(&set_limit_mutex);
2554 memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
2555 if (memswlimit < val) {
2556 ret = -EINVAL;
2557 mutex_unlock(&set_limit_mutex);
2558 break;
2560 ret = res_counter_set_limit(&memcg->res, val);
2561 if (!ret) {
2562 if (memswlimit == val)
2563 memcg->memsw_is_minimum = true;
2564 else
2565 memcg->memsw_is_minimum = false;
2567 mutex_unlock(&set_limit_mutex);
2569 if (!ret)
2570 break;
2572 mem_cgroup_hierarchical_reclaim(memcg, NULL, GFP_KERNEL,
2573 MEM_CGROUP_RECLAIM_SHRINK);
2574 curusage = res_counter_read_u64(&memcg->res, RES_USAGE);
2575 /* Usage is reduced ? */
2576 if (curusage >= oldusage)
2577 retry_count--;
2578 else
2579 oldusage = curusage;
2582 return ret;
2585 static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
2586 unsigned long long val)
2588 int retry_count;
2589 u64 memlimit, oldusage, curusage;
2590 int children = mem_cgroup_count_children(memcg);
2591 int ret = -EBUSY;
2593 /* see mem_cgroup_resize_res_limit */
2594 retry_count = children * MEM_CGROUP_RECLAIM_RETRIES;
2595 oldusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
2596 while (retry_count) {
2597 if (signal_pending(current)) {
2598 ret = -EINTR;
2599 break;
2602 * Rather than hide all in some function, I do this in
2603 * open coded manner. You see what this really does.
2604 * We have to guarantee mem->res.limit < mem->memsw.limit.
2606 mutex_lock(&set_limit_mutex);
2607 memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT);
2608 if (memlimit > val) {
2609 ret = -EINVAL;
2610 mutex_unlock(&set_limit_mutex);
2611 break;
2613 ret = res_counter_set_limit(&memcg->memsw, val);
2614 if (!ret) {
2615 if (memlimit == val)
2616 memcg->memsw_is_minimum = true;
2617 else
2618 memcg->memsw_is_minimum = false;
2620 mutex_unlock(&set_limit_mutex);
2622 if (!ret)
2623 break;
2625 mem_cgroup_hierarchical_reclaim(memcg, NULL, GFP_KERNEL,
2626 MEM_CGROUP_RECLAIM_NOSWAP |
2627 MEM_CGROUP_RECLAIM_SHRINK);
2628 curusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
2629 /* Usage is reduced ? */
2630 if (curusage >= oldusage)
2631 retry_count--;
2632 else
2633 oldusage = curusage;
2635 return ret;
2638 unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
2639 gfp_t gfp_mask, int nid,
2640 int zid)
2642 unsigned long nr_reclaimed = 0;
2643 struct mem_cgroup_per_zone *mz, *next_mz = NULL;
2644 unsigned long reclaimed;
2645 int loop = 0;
2646 struct mem_cgroup_tree_per_zone *mctz;
2647 unsigned long long excess;
2649 if (order > 0)
2650 return 0;
2652 mctz = soft_limit_tree_node_zone(nid, zid);
2654 * This loop can run a while, specially if mem_cgroup's continuously
2655 * keep exceeding their soft limit and putting the system under
2656 * pressure
2658 do {
2659 if (next_mz)
2660 mz = next_mz;
2661 else
2662 mz = mem_cgroup_largest_soft_limit_node(mctz);
2663 if (!mz)
2664 break;
2666 reclaimed = mem_cgroup_hierarchical_reclaim(mz->mem, zone,
2667 gfp_mask,
2668 MEM_CGROUP_RECLAIM_SOFT);
2669 nr_reclaimed += reclaimed;
2670 spin_lock(&mctz->lock);
2673 * If we failed to reclaim anything from this memory cgroup
2674 * it is time to move on to the next cgroup
2676 next_mz = NULL;
2677 if (!reclaimed) {
2678 do {
2680 * Loop until we find yet another one.
2682 * By the time we get the soft_limit lock
2683 * again, someone might have aded the
2684 * group back on the RB tree. Iterate to
2685 * make sure we get a different mem.
2686 * mem_cgroup_largest_soft_limit_node returns
2687 * NULL if no other cgroup is present on
2688 * the tree
2690 next_mz =
2691 __mem_cgroup_largest_soft_limit_node(mctz);
2692 if (next_mz == mz) {
2693 css_put(&next_mz->mem->css);
2694 next_mz = NULL;
2695 } else /* next_mz == NULL or other memcg */
2696 break;
2697 } while (1);
2699 __mem_cgroup_remove_exceeded(mz->mem, mz, mctz);
2700 excess = res_counter_soft_limit_excess(&mz->mem->res);
2702 * One school of thought says that we should not add
2703 * back the node to the tree if reclaim returns 0.
2704 * But our reclaim could return 0, simply because due
2705 * to priority we are exposing a smaller subset of
2706 * memory to reclaim from. Consider this as a longer
2707 * term TODO.
2709 /* If excess == 0, no tree ops */
2710 __mem_cgroup_insert_exceeded(mz->mem, mz, mctz, excess);
2711 spin_unlock(&mctz->lock);
2712 css_put(&mz->mem->css);
2713 loop++;
2715 * Could not reclaim anything and there are no more
2716 * mem cgroups to try or we seem to be looping without
2717 * reclaiming anything.
2719 if (!nr_reclaimed &&
2720 (next_mz == NULL ||
2721 loop > MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS))
2722 break;
2723 } while (!nr_reclaimed);
2724 if (next_mz)
2725 css_put(&next_mz->mem->css);
2726 return nr_reclaimed;
2730 * This routine traverse page_cgroup in given list and drop them all.
2731 * *And* this routine doesn't reclaim page itself, just removes page_cgroup.
2733 static int mem_cgroup_force_empty_list(struct mem_cgroup *mem,
2734 int node, int zid, enum lru_list lru)
2736 struct zone *zone;
2737 struct mem_cgroup_per_zone *mz;
2738 struct page_cgroup *pc, *busy;
2739 unsigned long flags, loop;
2740 struct list_head *list;
2741 int ret = 0;
2743 zone = &NODE_DATA(node)->node_zones[zid];
2744 mz = mem_cgroup_zoneinfo(mem, node, zid);
2745 list = &mz->lists[lru];
2747 loop = MEM_CGROUP_ZSTAT(mz, lru);
2748 /* give some margin against EBUSY etc...*/
2749 loop += 256;
2750 busy = NULL;
2751 while (loop--) {
2752 ret = 0;
2753 spin_lock_irqsave(&zone->lru_lock, flags);
2754 if (list_empty(list)) {
2755 spin_unlock_irqrestore(&zone->lru_lock, flags);
2756 break;
2758 pc = list_entry(list->prev, struct page_cgroup, lru);
2759 if (busy == pc) {
2760 list_move(&pc->lru, list);
2761 busy = NULL;
2762 spin_unlock_irqrestore(&zone->lru_lock, flags);
2763 continue;
2765 spin_unlock_irqrestore(&zone->lru_lock, flags);
2767 ret = mem_cgroup_move_parent(pc, mem, GFP_KERNEL);
2768 if (ret == -ENOMEM)
2769 break;
2771 if (ret == -EBUSY || ret == -EINVAL) {
2772 /* found lock contention or "pc" is obsolete. */
2773 busy = pc;
2774 cond_resched();
2775 } else
2776 busy = NULL;
2779 if (!ret && !list_empty(list))
2780 return -EBUSY;
2781 return ret;
2785 * make mem_cgroup's charge to be 0 if there is no task.
2786 * This enables deleting this mem_cgroup.
2788 static int mem_cgroup_force_empty(struct mem_cgroup *mem, bool free_all)
2790 int ret;
2791 int node, zid, shrink;
2792 int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
2793 struct cgroup *cgrp = mem->css.cgroup;
2795 css_get(&mem->css);
2797 shrink = 0;
2798 /* should free all ? */
2799 if (free_all)
2800 goto try_to_free;
2801 move_account:
2802 do {
2803 ret = -EBUSY;
2804 if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children))
2805 goto out;
2806 ret = -EINTR;
2807 if (signal_pending(current))
2808 goto out;
2809 /* This is for making all *used* pages to be on LRU. */
2810 lru_add_drain_all();
2811 drain_all_stock_sync();
2812 ret = 0;
2813 for_each_node_state(node, N_HIGH_MEMORY) {
2814 for (zid = 0; !ret && zid < MAX_NR_ZONES; zid++) {
2815 enum lru_list l;
2816 for_each_lru(l) {
2817 ret = mem_cgroup_force_empty_list(mem,
2818 node, zid, l);
2819 if (ret)
2820 break;
2823 if (ret)
2824 break;
2826 /* it seems parent cgroup doesn't have enough mem */
2827 if (ret == -ENOMEM)
2828 goto try_to_free;
2829 cond_resched();
2830 /* "ret" should also be checked to ensure all lists are empty. */
2831 } while (mem->res.usage > 0 || ret);
2832 out:
2833 css_put(&mem->css);
2834 return ret;
2836 try_to_free:
2837 /* returns EBUSY if there is a task or if we come here twice. */
2838 if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children) || shrink) {
2839 ret = -EBUSY;
2840 goto out;
2842 /* we call try-to-free pages for make this cgroup empty */
2843 lru_add_drain_all();
2844 /* try to free all pages in this cgroup */
2845 shrink = 1;
2846 while (nr_retries && mem->res.usage > 0) {
2847 int progress;
2849 if (signal_pending(current)) {
2850 ret = -EINTR;
2851 goto out;
2853 progress = try_to_free_mem_cgroup_pages(mem, GFP_KERNEL,
2854 false, get_swappiness(mem));
2855 if (!progress) {
2856 nr_retries--;
2857 /* maybe some writeback is necessary */
2858 congestion_wait(BLK_RW_ASYNC, HZ/10);
2862 lru_add_drain();
2863 /* try move_account...there may be some *locked* pages. */
2864 goto move_account;
2867 int mem_cgroup_force_empty_write(struct cgroup *cont, unsigned int event)
2869 return mem_cgroup_force_empty(mem_cgroup_from_cont(cont), true);
2873 static u64 mem_cgroup_hierarchy_read(struct cgroup *cont, struct cftype *cft)
2875 return mem_cgroup_from_cont(cont)->use_hierarchy;
2878 static int mem_cgroup_hierarchy_write(struct cgroup *cont, struct cftype *cft,
2879 u64 val)
2881 int retval = 0;
2882 struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
2883 struct cgroup *parent = cont->parent;
2884 struct mem_cgroup *parent_mem = NULL;
2886 if (parent)
2887 parent_mem = mem_cgroup_from_cont(parent);
2889 cgroup_lock();
2891 * If parent's use_hierarchy is set, we can't make any modifications
2892 * in the child subtrees. If it is unset, then the change can
2893 * occur, provided the current cgroup has no children.
2895 * For the root cgroup, parent_mem is NULL, we allow value to be
2896 * set if there are no children.
2898 if ((!parent_mem || !parent_mem->use_hierarchy) &&
2899 (val == 1 || val == 0)) {
2900 if (list_empty(&cont->children))
2901 mem->use_hierarchy = val;
2902 else
2903 retval = -EBUSY;
2904 } else
2905 retval = -EINVAL;
2906 cgroup_unlock();
2908 return retval;
2911 struct mem_cgroup_idx_data {
2912 s64 val;
2913 enum mem_cgroup_stat_index idx;
2916 static int
2917 mem_cgroup_get_idx_stat(struct mem_cgroup *mem, void *data)
2919 struct mem_cgroup_idx_data *d = data;
2920 d->val += mem_cgroup_read_stat(mem, d->idx);
2921 return 0;
2924 static void
2925 mem_cgroup_get_recursive_idx_stat(struct mem_cgroup *mem,
2926 enum mem_cgroup_stat_index idx, s64 *val)
2928 struct mem_cgroup_idx_data d;
2929 d.idx = idx;
2930 d.val = 0;
2931 mem_cgroup_walk_tree(mem, &d, mem_cgroup_get_idx_stat);
2932 *val = d.val;
2935 static inline u64 mem_cgroup_usage(struct mem_cgroup *mem, bool swap)
2937 u64 idx_val, val;
2939 if (!mem_cgroup_is_root(mem)) {
2940 if (!swap)
2941 return res_counter_read_u64(&mem->res, RES_USAGE);
2942 else
2943 return res_counter_read_u64(&mem->memsw, RES_USAGE);
2946 mem_cgroup_get_recursive_idx_stat(mem, MEM_CGROUP_STAT_CACHE, &idx_val);
2947 val = idx_val;
2948 mem_cgroup_get_recursive_idx_stat(mem, MEM_CGROUP_STAT_RSS, &idx_val);
2949 val += idx_val;
2951 if (swap) {
2952 mem_cgroup_get_recursive_idx_stat(mem,
2953 MEM_CGROUP_STAT_SWAPOUT, &idx_val);
2954 val += idx_val;
2957 return val << PAGE_SHIFT;
2960 static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft)
2962 struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
2963 u64 val;
2964 int type, name;
2966 type = MEMFILE_TYPE(cft->private);
2967 name = MEMFILE_ATTR(cft->private);
2968 switch (type) {
2969 case _MEM:
2970 if (name == RES_USAGE)
2971 val = mem_cgroup_usage(mem, false);
2972 else
2973 val = res_counter_read_u64(&mem->res, name);
2974 break;
2975 case _MEMSWAP:
2976 if (name == RES_USAGE)
2977 val = mem_cgroup_usage(mem, true);
2978 else
2979 val = res_counter_read_u64(&mem->memsw, name);
2980 break;
2981 default:
2982 BUG();
2983 break;
2985 return val;
2988 * The user of this function is...
2989 * RES_LIMIT.
2991 static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
2992 const char *buffer)
2994 struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
2995 int type, name;
2996 unsigned long long val;
2997 int ret;
2999 type = MEMFILE_TYPE(cft->private);
3000 name = MEMFILE_ATTR(cft->private);
3001 switch (name) {
3002 case RES_LIMIT:
3003 if (mem_cgroup_is_root(memcg)) { /* Can't set limit on root */
3004 ret = -EINVAL;
3005 break;
3007 /* This function does all necessary parse...reuse it */
3008 ret = res_counter_memparse_write_strategy(buffer, &val);
3009 if (ret)
3010 break;
3011 if (type == _MEM)
3012 ret = mem_cgroup_resize_limit(memcg, val);
3013 else
3014 ret = mem_cgroup_resize_memsw_limit(memcg, val);
3015 break;
3016 case RES_SOFT_LIMIT:
3017 ret = res_counter_memparse_write_strategy(buffer, &val);
3018 if (ret)
3019 break;
3021 * For memsw, soft limits are hard to implement in terms
3022 * of semantics, for now, we support soft limits for
3023 * control without swap
3025 if (type == _MEM)
3026 ret = res_counter_set_soft_limit(&memcg->res, val);
3027 else
3028 ret = -EINVAL;
3029 break;
3030 default:
3031 ret = -EINVAL; /* should be BUG() ? */
3032 break;
3034 return ret;
3037 static void memcg_get_hierarchical_limit(struct mem_cgroup *memcg,
3038 unsigned long long *mem_limit, unsigned long long *memsw_limit)
3040 struct cgroup *cgroup;
3041 unsigned long long min_limit, min_memsw_limit, tmp;
3043 min_limit = res_counter_read_u64(&memcg->res, RES_LIMIT);
3044 min_memsw_limit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
3045 cgroup = memcg->css.cgroup;
3046 if (!memcg->use_hierarchy)
3047 goto out;
3049 while (cgroup->parent) {
3050 cgroup = cgroup->parent;
3051 memcg = mem_cgroup_from_cont(cgroup);
3052 if (!memcg->use_hierarchy)
3053 break;
3054 tmp = res_counter_read_u64(&memcg->res, RES_LIMIT);
3055 min_limit = min(min_limit, tmp);
3056 tmp = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
3057 min_memsw_limit = min(min_memsw_limit, tmp);
3059 out:
3060 *mem_limit = min_limit;
3061 *memsw_limit = min_memsw_limit;
3062 return;
3065 static int mem_cgroup_reset(struct cgroup *cont, unsigned int event)
3067 struct mem_cgroup *mem;
3068 int type, name;
3070 mem = mem_cgroup_from_cont(cont);
3071 type = MEMFILE_TYPE(event);
3072 name = MEMFILE_ATTR(event);
3073 switch (name) {
3074 case RES_MAX_USAGE:
3075 if (type == _MEM)
3076 res_counter_reset_max(&mem->res);
3077 else
3078 res_counter_reset_max(&mem->memsw);
3079 break;
3080 case RES_FAILCNT:
3081 if (type == _MEM)
3082 res_counter_reset_failcnt(&mem->res);
3083 else
3084 res_counter_reset_failcnt(&mem->memsw);
3085 break;
3088 return 0;
3091 static u64 mem_cgroup_move_charge_read(struct cgroup *cgrp,
3092 struct cftype *cft)
3094 return mem_cgroup_from_cont(cgrp)->move_charge_at_immigrate;
3097 #ifdef CONFIG_MMU
3098 static int mem_cgroup_move_charge_write(struct cgroup *cgrp,
3099 struct cftype *cft, u64 val)
3101 struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp);
3103 if (val >= (1 << NR_MOVE_TYPE))
3104 return -EINVAL;
3106 * We check this value several times in both in can_attach() and
3107 * attach(), so we need cgroup lock to prevent this value from being
3108 * inconsistent.
3110 cgroup_lock();
3111 mem->move_charge_at_immigrate = val;
3112 cgroup_unlock();
3114 return 0;
3116 #else
3117 static int mem_cgroup_move_charge_write(struct cgroup *cgrp,
3118 struct cftype *cft, u64 val)
3120 return -ENOSYS;
3122 #endif
3125 /* For read statistics */
3126 enum {
3127 MCS_CACHE,
3128 MCS_RSS,
3129 MCS_FILE_MAPPED,
3130 MCS_PGPGIN,
3131 MCS_PGPGOUT,
3132 MCS_SWAP,
3133 MCS_INACTIVE_ANON,
3134 MCS_ACTIVE_ANON,
3135 MCS_INACTIVE_FILE,
3136 MCS_ACTIVE_FILE,
3137 MCS_UNEVICTABLE,
3138 NR_MCS_STAT,
3141 struct mcs_total_stat {
3142 s64 stat[NR_MCS_STAT];
3145 struct {
3146 char *local_name;
3147 char *total_name;
3148 } memcg_stat_strings[NR_MCS_STAT] = {
3149 {"cache", "total_cache"},
3150 {"rss", "total_rss"},
3151 {"mapped_file", "total_mapped_file"},
3152 {"pgpgin", "total_pgpgin"},
3153 {"pgpgout", "total_pgpgout"},
3154 {"swap", "total_swap"},
3155 {"inactive_anon", "total_inactive_anon"},
3156 {"active_anon", "total_active_anon"},
3157 {"inactive_file", "total_inactive_file"},
3158 {"active_file", "total_active_file"},
3159 {"unevictable", "total_unevictable"}
3163 static int mem_cgroup_get_local_stat(struct mem_cgroup *mem, void *data)
3165 struct mcs_total_stat *s = data;
3166 s64 val;
3168 /* per cpu stat */
3169 val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_CACHE);
3170 s->stat[MCS_CACHE] += val * PAGE_SIZE;
3171 val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_RSS);
3172 s->stat[MCS_RSS] += val * PAGE_SIZE;
3173 val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_FILE_MAPPED);
3174 s->stat[MCS_FILE_MAPPED] += val * PAGE_SIZE;
3175 val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_PGPGIN_COUNT);
3176 s->stat[MCS_PGPGIN] += val;
3177 val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_PGPGOUT_COUNT);
3178 s->stat[MCS_PGPGOUT] += val;
3179 if (do_swap_account) {
3180 val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_SWAPOUT);
3181 s->stat[MCS_SWAP] += val * PAGE_SIZE;
3184 /* per zone stat */
3185 val = mem_cgroup_get_local_zonestat(mem, LRU_INACTIVE_ANON);
3186 s->stat[MCS_INACTIVE_ANON] += val * PAGE_SIZE;
3187 val = mem_cgroup_get_local_zonestat(mem, LRU_ACTIVE_ANON);
3188 s->stat[MCS_ACTIVE_ANON] += val * PAGE_SIZE;
3189 val = mem_cgroup_get_local_zonestat(mem, LRU_INACTIVE_FILE);
3190 s->stat[MCS_INACTIVE_FILE] += val * PAGE_SIZE;
3191 val = mem_cgroup_get_local_zonestat(mem, LRU_ACTIVE_FILE);
3192 s->stat[MCS_ACTIVE_FILE] += val * PAGE_SIZE;
3193 val = mem_cgroup_get_local_zonestat(mem, LRU_UNEVICTABLE);
3194 s->stat[MCS_UNEVICTABLE] += val * PAGE_SIZE;
3195 return 0;
3198 static void
3199 mem_cgroup_get_total_stat(struct mem_cgroup *mem, struct mcs_total_stat *s)
3201 mem_cgroup_walk_tree(mem, s, mem_cgroup_get_local_stat);
3204 static int mem_control_stat_show(struct cgroup *cont, struct cftype *cft,
3205 struct cgroup_map_cb *cb)
3207 struct mem_cgroup *mem_cont = mem_cgroup_from_cont(cont);
3208 struct mcs_total_stat mystat;
3209 int i;
3211 memset(&mystat, 0, sizeof(mystat));
3212 mem_cgroup_get_local_stat(mem_cont, &mystat);
3214 for (i = 0; i < NR_MCS_STAT; i++) {
3215 if (i == MCS_SWAP && !do_swap_account)
3216 continue;
3217 cb->fill(cb, memcg_stat_strings[i].local_name, mystat.stat[i]);
3220 /* Hierarchical information */
3222 unsigned long long limit, memsw_limit;
3223 memcg_get_hierarchical_limit(mem_cont, &limit, &memsw_limit);
3224 cb->fill(cb, "hierarchical_memory_limit", limit);
3225 if (do_swap_account)
3226 cb->fill(cb, "hierarchical_memsw_limit", memsw_limit);
3229 memset(&mystat, 0, sizeof(mystat));
3230 mem_cgroup_get_total_stat(mem_cont, &mystat);
3231 for (i = 0; i < NR_MCS_STAT; i++) {
3232 if (i == MCS_SWAP && !do_swap_account)
3233 continue;
3234 cb->fill(cb, memcg_stat_strings[i].total_name, mystat.stat[i]);
3237 #ifdef CONFIG_DEBUG_VM
3238 cb->fill(cb, "inactive_ratio", calc_inactive_ratio(mem_cont, NULL));
3241 int nid, zid;
3242 struct mem_cgroup_per_zone *mz;
3243 unsigned long recent_rotated[2] = {0, 0};
3244 unsigned long recent_scanned[2] = {0, 0};
3246 for_each_online_node(nid)
3247 for (zid = 0; zid < MAX_NR_ZONES; zid++) {
3248 mz = mem_cgroup_zoneinfo(mem_cont, nid, zid);
3250 recent_rotated[0] +=
3251 mz->reclaim_stat.recent_rotated[0];
3252 recent_rotated[1] +=
3253 mz->reclaim_stat.recent_rotated[1];
3254 recent_scanned[0] +=
3255 mz->reclaim_stat.recent_scanned[0];
3256 recent_scanned[1] +=
3257 mz->reclaim_stat.recent_scanned[1];
3259 cb->fill(cb, "recent_rotated_anon", recent_rotated[0]);
3260 cb->fill(cb, "recent_rotated_file", recent_rotated[1]);
3261 cb->fill(cb, "recent_scanned_anon", recent_scanned[0]);
3262 cb->fill(cb, "recent_scanned_file", recent_scanned[1]);
3264 #endif
3266 return 0;
3269 static u64 mem_cgroup_swappiness_read(struct cgroup *cgrp, struct cftype *cft)
3271 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
3273 return get_swappiness(memcg);
3276 static int mem_cgroup_swappiness_write(struct cgroup *cgrp, struct cftype *cft,
3277 u64 val)
3279 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
3280 struct mem_cgroup *parent;
3282 if (val > 100)
3283 return -EINVAL;
3285 if (cgrp->parent == NULL)
3286 return -EINVAL;
3288 parent = mem_cgroup_from_cont(cgrp->parent);
3290 cgroup_lock();
3292 /* If under hierarchy, only empty-root can set this value */
3293 if ((parent->use_hierarchy) ||
3294 (memcg->use_hierarchy && !list_empty(&cgrp->children))) {
3295 cgroup_unlock();
3296 return -EINVAL;
3299 spin_lock(&memcg->reclaim_param_lock);
3300 memcg->swappiness = val;
3301 spin_unlock(&memcg->reclaim_param_lock);
3303 cgroup_unlock();
3305 return 0;
3308 static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap)
3310 struct mem_cgroup_threshold_ary *t;
3311 u64 usage;
3312 int i;
3314 rcu_read_lock();
3315 if (!swap)
3316 t = rcu_dereference(memcg->thresholds);
3317 else
3318 t = rcu_dereference(memcg->memsw_thresholds);
3320 if (!t)
3321 goto unlock;
3323 usage = mem_cgroup_usage(memcg, swap);
3326 * current_threshold points to threshold just below usage.
3327 * If it's not true, a threshold was crossed after last
3328 * call of __mem_cgroup_threshold().
3330 i = atomic_read(&t->current_threshold);
3333 * Iterate backward over array of thresholds starting from
3334 * current_threshold and check if a threshold is crossed.
3335 * If none of thresholds below usage is crossed, we read
3336 * only one element of the array here.
3338 for (; i >= 0 && unlikely(t->entries[i].threshold > usage); i--)
3339 eventfd_signal(t->entries[i].eventfd, 1);
3341 /* i = current_threshold + 1 */
3342 i++;
3345 * Iterate forward over array of thresholds starting from
3346 * current_threshold+1 and check if a threshold is crossed.
3347 * If none of thresholds above usage is crossed, we read
3348 * only one element of the array here.
3350 for (; i < t->size && unlikely(t->entries[i].threshold <= usage); i++)
3351 eventfd_signal(t->entries[i].eventfd, 1);
3353 /* Update current_threshold */
3354 atomic_set(&t->current_threshold, i - 1);
3355 unlock:
3356 rcu_read_unlock();
3359 static void mem_cgroup_threshold(struct mem_cgroup *memcg)
3361 __mem_cgroup_threshold(memcg, false);
3362 if (do_swap_account)
3363 __mem_cgroup_threshold(memcg, true);
3366 static int compare_thresholds(const void *a, const void *b)
3368 const struct mem_cgroup_threshold *_a = a;
3369 const struct mem_cgroup_threshold *_b = b;
3371 return _a->threshold - _b->threshold;
3374 static int mem_cgroup_register_event(struct cgroup *cgrp, struct cftype *cft,
3375 struct eventfd_ctx *eventfd, const char *args)
3377 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
3378 struct mem_cgroup_threshold_ary *thresholds, *thresholds_new;
3379 int type = MEMFILE_TYPE(cft->private);
3380 u64 threshold, usage;
3381 int size;
3382 int i, ret;
3384 ret = res_counter_memparse_write_strategy(args, &threshold);
3385 if (ret)
3386 return ret;
3388 mutex_lock(&memcg->thresholds_lock);
3389 if (type == _MEM)
3390 thresholds = memcg->thresholds;
3391 else if (type == _MEMSWAP)
3392 thresholds = memcg->memsw_thresholds;
3393 else
3394 BUG();
3396 usage = mem_cgroup_usage(memcg, type == _MEMSWAP);
3398 /* Check if a threshold crossed before adding a new one */
3399 if (thresholds)
3400 __mem_cgroup_threshold(memcg, type == _MEMSWAP);
3402 if (thresholds)
3403 size = thresholds->size + 1;
3404 else
3405 size = 1;
3407 /* Allocate memory for new array of thresholds */
3408 thresholds_new = kmalloc(sizeof(*thresholds_new) +
3409 size * sizeof(struct mem_cgroup_threshold),
3410 GFP_KERNEL);
3411 if (!thresholds_new) {
3412 ret = -ENOMEM;
3413 goto unlock;
3415 thresholds_new->size = size;
3417 /* Copy thresholds (if any) to new array */
3418 if (thresholds)
3419 memcpy(thresholds_new->entries, thresholds->entries,
3420 thresholds->size *
3421 sizeof(struct mem_cgroup_threshold));
3422 /* Add new threshold */
3423 thresholds_new->entries[size - 1].eventfd = eventfd;
3424 thresholds_new->entries[size - 1].threshold = threshold;
3426 /* Sort thresholds. Registering of new threshold isn't time-critical */
3427 sort(thresholds_new->entries, size,
3428 sizeof(struct mem_cgroup_threshold),
3429 compare_thresholds, NULL);
3431 /* Find current threshold */
3432 atomic_set(&thresholds_new->current_threshold, -1);
3433 for (i = 0; i < size; i++) {
3434 if (thresholds_new->entries[i].threshold < usage) {
3436 * thresholds_new->current_threshold will not be used
3437 * until rcu_assign_pointer(), so it's safe to increment
3438 * it here.
3440 atomic_inc(&thresholds_new->current_threshold);
3444 if (type == _MEM)
3445 rcu_assign_pointer(memcg->thresholds, thresholds_new);
3446 else
3447 rcu_assign_pointer(memcg->memsw_thresholds, thresholds_new);
3449 /* To be sure that nobody uses thresholds before freeing it */
3450 synchronize_rcu();
3452 kfree(thresholds);
3453 unlock:
3454 mutex_unlock(&memcg->thresholds_lock);
3456 return ret;
3459 static int mem_cgroup_unregister_event(struct cgroup *cgrp, struct cftype *cft,
3460 struct eventfd_ctx *eventfd)
3462 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
3463 struct mem_cgroup_threshold_ary *thresholds, *thresholds_new;
3464 int type = MEMFILE_TYPE(cft->private);
3465 u64 usage;
3466 int size = 0;
3467 int i, j, ret;
3469 mutex_lock(&memcg->thresholds_lock);
3470 if (type == _MEM)
3471 thresholds = memcg->thresholds;
3472 else if (type == _MEMSWAP)
3473 thresholds = memcg->memsw_thresholds;
3474 else
3475 BUG();
3478 * Something went wrong if we trying to unregister a threshold
3479 * if we don't have thresholds
3481 BUG_ON(!thresholds);
3483 usage = mem_cgroup_usage(memcg, type == _MEMSWAP);
3485 /* Check if a threshold crossed before removing */
3486 __mem_cgroup_threshold(memcg, type == _MEMSWAP);
3488 /* Calculate new number of threshold */
3489 for (i = 0; i < thresholds->size; i++) {
3490 if (thresholds->entries[i].eventfd != eventfd)
3491 size++;
3494 /* Set thresholds array to NULL if we don't have thresholds */
3495 if (!size) {
3496 thresholds_new = NULL;
3497 goto assign;
3500 /* Allocate memory for new array of thresholds */
3501 thresholds_new = kmalloc(sizeof(*thresholds_new) +
3502 size * sizeof(struct mem_cgroup_threshold),
3503 GFP_KERNEL);
3504 if (!thresholds_new) {
3505 ret = -ENOMEM;
3506 goto unlock;
3508 thresholds_new->size = size;
3510 /* Copy thresholds and find current threshold */
3511 atomic_set(&thresholds_new->current_threshold, -1);
3512 for (i = 0, j = 0; i < thresholds->size; i++) {
3513 if (thresholds->entries[i].eventfd == eventfd)
3514 continue;
3516 thresholds_new->entries[j] = thresholds->entries[i];
3517 if (thresholds_new->entries[j].threshold < usage) {
3519 * thresholds_new->current_threshold will not be used
3520 * until rcu_assign_pointer(), so it's safe to increment
3521 * it here.
3523 atomic_inc(&thresholds_new->current_threshold);
3525 j++;
3528 assign:
3529 if (type == _MEM)
3530 rcu_assign_pointer(memcg->thresholds, thresholds_new);
3531 else
3532 rcu_assign_pointer(memcg->memsw_thresholds, thresholds_new);
3534 /* To be sure that nobody uses thresholds before freeing it */
3535 synchronize_rcu();
3537 kfree(thresholds);
3538 unlock:
3539 mutex_unlock(&memcg->thresholds_lock);
3541 return ret;
3544 static struct cftype mem_cgroup_files[] = {
3546 .name = "usage_in_bytes",
3547 .private = MEMFILE_PRIVATE(_MEM, RES_USAGE),
3548 .read_u64 = mem_cgroup_read,
3549 .register_event = mem_cgroup_register_event,
3550 .unregister_event = mem_cgroup_unregister_event,
3553 .name = "max_usage_in_bytes",
3554 .private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE),
3555 .trigger = mem_cgroup_reset,
3556 .read_u64 = mem_cgroup_read,
3559 .name = "limit_in_bytes",
3560 .private = MEMFILE_PRIVATE(_MEM, RES_LIMIT),
3561 .write_string = mem_cgroup_write,
3562 .read_u64 = mem_cgroup_read,
3565 .name = "soft_limit_in_bytes",
3566 .private = MEMFILE_PRIVATE(_MEM, RES_SOFT_LIMIT),
3567 .write_string = mem_cgroup_write,
3568 .read_u64 = mem_cgroup_read,
3571 .name = "failcnt",
3572 .private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT),
3573 .trigger = mem_cgroup_reset,
3574 .read_u64 = mem_cgroup_read,
3577 .name = "stat",
3578 .read_map = mem_control_stat_show,
3581 .name = "force_empty",
3582 .trigger = mem_cgroup_force_empty_write,
3585 .name = "use_hierarchy",
3586 .write_u64 = mem_cgroup_hierarchy_write,
3587 .read_u64 = mem_cgroup_hierarchy_read,
3590 .name = "swappiness",
3591 .read_u64 = mem_cgroup_swappiness_read,
3592 .write_u64 = mem_cgroup_swappiness_write,
3595 .name = "move_charge_at_immigrate",
3596 .read_u64 = mem_cgroup_move_charge_read,
3597 .write_u64 = mem_cgroup_move_charge_write,
3601 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
3602 static struct cftype memsw_cgroup_files[] = {
3604 .name = "memsw.usage_in_bytes",
3605 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE),
3606 .read_u64 = mem_cgroup_read,
3607 .register_event = mem_cgroup_register_event,
3608 .unregister_event = mem_cgroup_unregister_event,
3611 .name = "memsw.max_usage_in_bytes",
3612 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE),
3613 .trigger = mem_cgroup_reset,
3614 .read_u64 = mem_cgroup_read,
3617 .name = "memsw.limit_in_bytes",
3618 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT),
3619 .write_string = mem_cgroup_write,
3620 .read_u64 = mem_cgroup_read,
3623 .name = "memsw.failcnt",
3624 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT),
3625 .trigger = mem_cgroup_reset,
3626 .read_u64 = mem_cgroup_read,
3630 static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss)
3632 if (!do_swap_account)
3633 return 0;
3634 return cgroup_add_files(cont, ss, memsw_cgroup_files,
3635 ARRAY_SIZE(memsw_cgroup_files));
3637 #else
3638 static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss)
3640 return 0;
3642 #endif
3644 static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
3646 struct mem_cgroup_per_node *pn;
3647 struct mem_cgroup_per_zone *mz;
3648 enum lru_list l;
3649 int zone, tmp = node;
3651 * This routine is called against possible nodes.
3652 * But it's BUG to call kmalloc() against offline node.
3654 * TODO: this routine can waste much memory for nodes which will
3655 * never be onlined. It's better to use memory hotplug callback
3656 * function.
3658 if (!node_state(node, N_NORMAL_MEMORY))
3659 tmp = -1;
3660 pn = kmalloc_node(sizeof(*pn), GFP_KERNEL, tmp);
3661 if (!pn)
3662 return 1;
3664 mem->info.nodeinfo[node] = pn;
3665 memset(pn, 0, sizeof(*pn));
3667 for (zone = 0; zone < MAX_NR_ZONES; zone++) {
3668 mz = &pn->zoneinfo[zone];
3669 for_each_lru(l)
3670 INIT_LIST_HEAD(&mz->lists[l]);
3671 mz->usage_in_excess = 0;
3672 mz->on_tree = false;
3673 mz->mem = mem;
3675 return 0;
3678 static void free_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
3680 kfree(mem->info.nodeinfo[node]);
3683 static struct mem_cgroup *mem_cgroup_alloc(void)
3685 struct mem_cgroup *mem;
3686 int size = sizeof(struct mem_cgroup);
3688 /* Can be very big if MAX_NUMNODES is very big */
3689 if (size < PAGE_SIZE)
3690 mem = kmalloc(size, GFP_KERNEL);
3691 else
3692 mem = vmalloc(size);
3694 if (!mem)
3695 return NULL;
3697 memset(mem, 0, size);
3698 mem->stat = alloc_percpu(struct mem_cgroup_stat_cpu);
3699 if (!mem->stat) {
3700 if (size < PAGE_SIZE)
3701 kfree(mem);
3702 else
3703 vfree(mem);
3704 mem = NULL;
3706 return mem;
3710 * At destroying mem_cgroup, references from swap_cgroup can remain.
3711 * (scanning all at force_empty is too costly...)
3713 * Instead of clearing all references at force_empty, we remember
3714 * the number of reference from swap_cgroup and free mem_cgroup when
3715 * it goes down to 0.
3717 * Removal of cgroup itself succeeds regardless of refs from swap.
3720 static void __mem_cgroup_free(struct mem_cgroup *mem)
3722 int node;
3724 mem_cgroup_remove_from_trees(mem);
3725 free_css_id(&mem_cgroup_subsys, &mem->css);
3727 for_each_node_state(node, N_POSSIBLE)
3728 free_mem_cgroup_per_zone_info(mem, node);
3730 free_percpu(mem->stat);
3731 if (sizeof(struct mem_cgroup) < PAGE_SIZE)
3732 kfree(mem);
3733 else
3734 vfree(mem);
3737 static void mem_cgroup_get(struct mem_cgroup *mem)
3739 atomic_inc(&mem->refcnt);
3742 static void __mem_cgroup_put(struct mem_cgroup *mem, int count)
3744 if (atomic_sub_and_test(count, &mem->refcnt)) {
3745 struct mem_cgroup *parent = parent_mem_cgroup(mem);
3746 __mem_cgroup_free(mem);
3747 if (parent)
3748 mem_cgroup_put(parent);
3752 static void mem_cgroup_put(struct mem_cgroup *mem)
3754 __mem_cgroup_put(mem, 1);
3758 * Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled.
3760 static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem)
3762 if (!mem->res.parent)
3763 return NULL;
3764 return mem_cgroup_from_res_counter(mem->res.parent, res);
3767 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
3768 static void __init enable_swap_cgroup(void)
3770 if (!mem_cgroup_disabled() && really_do_swap_account)
3771 do_swap_account = 1;
3773 #else
3774 static void __init enable_swap_cgroup(void)
3777 #endif
3779 static int mem_cgroup_soft_limit_tree_init(void)
3781 struct mem_cgroup_tree_per_node *rtpn;
3782 struct mem_cgroup_tree_per_zone *rtpz;
3783 int tmp, node, zone;
3785 for_each_node_state(node, N_POSSIBLE) {
3786 tmp = node;
3787 if (!node_state(node, N_NORMAL_MEMORY))
3788 tmp = -1;
3789 rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL, tmp);
3790 if (!rtpn)
3791 return 1;
3793 soft_limit_tree.rb_tree_per_node[node] = rtpn;
3795 for (zone = 0; zone < MAX_NR_ZONES; zone++) {
3796 rtpz = &rtpn->rb_tree_per_zone[zone];
3797 rtpz->rb_root = RB_ROOT;
3798 spin_lock_init(&rtpz->lock);
3801 return 0;
3804 static struct cgroup_subsys_state * __ref
3805 mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
3807 struct mem_cgroup *mem, *parent;
3808 long error = -ENOMEM;
3809 int node;
3811 mem = mem_cgroup_alloc();
3812 if (!mem)
3813 return ERR_PTR(error);
3815 for_each_node_state(node, N_POSSIBLE)
3816 if (alloc_mem_cgroup_per_zone_info(mem, node))
3817 goto free_out;
3819 /* root ? */
3820 if (cont->parent == NULL) {
3821 int cpu;
3822 enable_swap_cgroup();
3823 parent = NULL;
3824 root_mem_cgroup = mem;
3825 if (mem_cgroup_soft_limit_tree_init())
3826 goto free_out;
3827 for_each_possible_cpu(cpu) {
3828 struct memcg_stock_pcp *stock =
3829 &per_cpu(memcg_stock, cpu);
3830 INIT_WORK(&stock->work, drain_local_stock);
3832 hotcpu_notifier(memcg_stock_cpu_callback, 0);
3833 } else {
3834 parent = mem_cgroup_from_cont(cont->parent);
3835 mem->use_hierarchy = parent->use_hierarchy;
3838 if (parent && parent->use_hierarchy) {
3839 res_counter_init(&mem->res, &parent->res);
3840 res_counter_init(&mem->memsw, &parent->memsw);
3842 * We increment refcnt of the parent to ensure that we can
3843 * safely access it on res_counter_charge/uncharge.
3844 * This refcnt will be decremented when freeing this
3845 * mem_cgroup(see mem_cgroup_put).
3847 mem_cgroup_get(parent);
3848 } else {
3849 res_counter_init(&mem->res, NULL);
3850 res_counter_init(&mem->memsw, NULL);
3852 mem->last_scanned_child = 0;
3853 spin_lock_init(&mem->reclaim_param_lock);
3855 if (parent)
3856 mem->swappiness = get_swappiness(parent);
3857 atomic_set(&mem->refcnt, 1);
3858 mem->move_charge_at_immigrate = 0;
3859 mutex_init(&mem->thresholds_lock);
3860 return &mem->css;
3861 free_out:
3862 __mem_cgroup_free(mem);
3863 root_mem_cgroup = NULL;
3864 return ERR_PTR(error);
3867 static int mem_cgroup_pre_destroy(struct cgroup_subsys *ss,
3868 struct cgroup *cont)
3870 struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
3872 return mem_cgroup_force_empty(mem, false);
3875 static void mem_cgroup_destroy(struct cgroup_subsys *ss,
3876 struct cgroup *cont)
3878 struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
3880 mem_cgroup_put(mem);
3883 static int mem_cgroup_populate(struct cgroup_subsys *ss,
3884 struct cgroup *cont)
3886 int ret;
3888 ret = cgroup_add_files(cont, ss, mem_cgroup_files,
3889 ARRAY_SIZE(mem_cgroup_files));
3891 if (!ret)
3892 ret = register_memsw_files(cont, ss);
3893 return ret;
3896 #ifdef CONFIG_MMU
3897 /* Handlers for move charge at task migration. */
3898 #define PRECHARGE_COUNT_AT_ONCE 256
3899 static int mem_cgroup_do_precharge(unsigned long count)
3901 int ret = 0;
3902 int batch_count = PRECHARGE_COUNT_AT_ONCE;
3903 struct mem_cgroup *mem = mc.to;
3905 if (mem_cgroup_is_root(mem)) {
3906 mc.precharge += count;
3907 /* we don't need css_get for root */
3908 return ret;
3910 /* try to charge at once */
3911 if (count > 1) {
3912 struct res_counter *dummy;
3914 * "mem" cannot be under rmdir() because we've already checked
3915 * by cgroup_lock_live_cgroup() that it is not removed and we
3916 * are still under the same cgroup_mutex. So we can postpone
3917 * css_get().
3919 if (res_counter_charge(&mem->res, PAGE_SIZE * count, &dummy))
3920 goto one_by_one;
3921 if (do_swap_account && res_counter_charge(&mem->memsw,
3922 PAGE_SIZE * count, &dummy)) {
3923 res_counter_uncharge(&mem->res, PAGE_SIZE * count);
3924 goto one_by_one;
3926 mc.precharge += count;
3927 VM_BUG_ON(test_bit(CSS_ROOT, &mem->css.flags));
3928 WARN_ON_ONCE(count > INT_MAX);
3929 __css_get(&mem->css, (int)count);
3930 return ret;
3932 one_by_one:
3933 /* fall back to one by one charge */
3934 while (count--) {
3935 if (signal_pending(current)) {
3936 ret = -EINTR;
3937 break;
3939 if (!batch_count--) {
3940 batch_count = PRECHARGE_COUNT_AT_ONCE;
3941 cond_resched();
3943 ret = __mem_cgroup_try_charge(NULL, GFP_KERNEL, &mem, false);
3944 if (ret || !mem)
3945 /* mem_cgroup_clear_mc() will do uncharge later */
3946 return -ENOMEM;
3947 mc.precharge++;
3949 return ret;
3953 * is_target_pte_for_mc - check a pte whether it is valid for move charge
3954 * @vma: the vma the pte to be checked belongs
3955 * @addr: the address corresponding to the pte to be checked
3956 * @ptent: the pte to be checked
3957 * @target: the pointer the target page or swap ent will be stored(can be NULL)
3959 * Returns
3960 * 0(MC_TARGET_NONE): if the pte is not a target for move charge.
3961 * 1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for
3962 * move charge. if @target is not NULL, the page is stored in target->page
3963 * with extra refcnt got(Callers should handle it).
3964 * 2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a
3965 * target for charge migration. if @target is not NULL, the entry is stored
3966 * in target->ent.
3968 * Called with pte lock held.
3970 union mc_target {
3971 struct page *page;
3972 swp_entry_t ent;
3975 enum mc_target_type {
3976 MC_TARGET_NONE, /* not used */
3977 MC_TARGET_PAGE,
3978 MC_TARGET_SWAP,
3981 static int is_target_pte_for_mc(struct vm_area_struct *vma,
3982 unsigned long addr, pte_t ptent, union mc_target *target)
3984 struct page *page = NULL;
3985 struct page_cgroup *pc;
3986 int ret = 0;
3987 swp_entry_t ent = { .val = 0 };
3988 int usage_count = 0;
3989 bool move_anon = test_bit(MOVE_CHARGE_TYPE_ANON,
3990 &mc.to->move_charge_at_immigrate);
3992 if (!pte_present(ptent)) {
3993 /* TODO: handle swap of shmes/tmpfs */
3994 if (pte_none(ptent) || pte_file(ptent))
3995 return 0;
3996 else if (is_swap_pte(ptent)) {
3997 ent = pte_to_swp_entry(ptent);
3998 if (!move_anon || non_swap_entry(ent))
3999 return 0;
4000 usage_count = mem_cgroup_count_swap_user(ent, &page);
4002 } else {
4003 page = vm_normal_page(vma, addr, ptent);
4004 if (!page || !page_mapped(page))
4005 return 0;
4007 * TODO: We don't move charges of file(including shmem/tmpfs)
4008 * pages for now.
4010 if (!move_anon || !PageAnon(page))
4011 return 0;
4012 if (!get_page_unless_zero(page))
4013 return 0;
4014 usage_count = page_mapcount(page);
4016 if (usage_count > 1) {
4018 * TODO: We don't move charges of shared(used by multiple
4019 * processes) pages for now.
4021 if (page)
4022 put_page(page);
4023 return 0;
4025 if (page) {
4026 pc = lookup_page_cgroup(page);
4028 * Do only loose check w/o page_cgroup lock.
4029 * mem_cgroup_move_account() checks the pc is valid or not under
4030 * the lock.
4032 if (PageCgroupUsed(pc) && pc->mem_cgroup == mc.from) {
4033 ret = MC_TARGET_PAGE;
4034 if (target)
4035 target->page = page;
4037 if (!ret || !target)
4038 put_page(page);
4040 /* throught */
4041 if (ent.val && do_swap_account && !ret &&
4042 css_id(&mc.from->css) == lookup_swap_cgroup(ent)) {
4043 ret = MC_TARGET_SWAP;
4044 if (target)
4045 target->ent = ent;
4047 return ret;
4050 static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd,
4051 unsigned long addr, unsigned long end,
4052 struct mm_walk *walk)
4054 struct vm_area_struct *vma = walk->private;
4055 pte_t *pte;
4056 spinlock_t *ptl;
4058 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
4059 for (; addr != end; pte++, addr += PAGE_SIZE)
4060 if (is_target_pte_for_mc(vma, addr, *pte, NULL))
4061 mc.precharge++; /* increment precharge temporarily */
4062 pte_unmap_unlock(pte - 1, ptl);
4063 cond_resched();
4065 return 0;
4068 static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm)
4070 unsigned long precharge;
4071 struct vm_area_struct *vma;
4073 down_read(&mm->mmap_sem);
4074 for (vma = mm->mmap; vma; vma = vma->vm_next) {
4075 struct mm_walk mem_cgroup_count_precharge_walk = {
4076 .pmd_entry = mem_cgroup_count_precharge_pte_range,
4077 .mm = mm,
4078 .private = vma,
4080 if (is_vm_hugetlb_page(vma))
4081 continue;
4082 /* TODO: We don't move charges of shmem/tmpfs pages for now. */
4083 if (vma->vm_flags & VM_SHARED)
4084 continue;
4085 walk_page_range(vma->vm_start, vma->vm_end,
4086 &mem_cgroup_count_precharge_walk);
4088 up_read(&mm->mmap_sem);
4090 precharge = mc.precharge;
4091 mc.precharge = 0;
4093 return precharge;
4096 static int mem_cgroup_precharge_mc(struct mm_struct *mm)
4098 return mem_cgroup_do_precharge(mem_cgroup_count_precharge(mm));
4101 static void mem_cgroup_clear_mc(void)
4103 /* we must uncharge all the leftover precharges from mc.to */
4104 if (mc.precharge) {
4105 __mem_cgroup_cancel_charge(mc.to, mc.precharge);
4106 mc.precharge = 0;
4109 * we didn't uncharge from mc.from at mem_cgroup_move_account(), so
4110 * we must uncharge here.
4112 if (mc.moved_charge) {
4113 __mem_cgroup_cancel_charge(mc.from, mc.moved_charge);
4114 mc.moved_charge = 0;
4116 /* we must fixup refcnts and charges */
4117 if (mc.moved_swap) {
4118 WARN_ON_ONCE(mc.moved_swap > INT_MAX);
4119 /* uncharge swap account from the old cgroup */
4120 if (!mem_cgroup_is_root(mc.from))
4121 res_counter_uncharge(&mc.from->memsw,
4122 PAGE_SIZE * mc.moved_swap);
4123 __mem_cgroup_put(mc.from, mc.moved_swap);
4125 if (!mem_cgroup_is_root(mc.to)) {
4127 * we charged both to->res and to->memsw, so we should
4128 * uncharge to->res.
4130 res_counter_uncharge(&mc.to->res,
4131 PAGE_SIZE * mc.moved_swap);
4132 VM_BUG_ON(test_bit(CSS_ROOT, &mc.to->css.flags));
4133 __css_put(&mc.to->css, mc.moved_swap);
4135 /* we've already done mem_cgroup_get(mc.to) */
4137 mc.moved_swap = 0;
4139 mc.from = NULL;
4140 mc.to = NULL;
4141 mc.moving_task = NULL;
4142 wake_up_all(&mc.waitq);
4145 static int mem_cgroup_can_attach(struct cgroup_subsys *ss,
4146 struct cgroup *cgroup,
4147 struct task_struct *p,
4148 bool threadgroup)
4150 int ret = 0;
4151 struct mem_cgroup *mem = mem_cgroup_from_cont(cgroup);
4153 if (mem->move_charge_at_immigrate) {
4154 struct mm_struct *mm;
4155 struct mem_cgroup *from = mem_cgroup_from_task(p);
4157 VM_BUG_ON(from == mem);
4159 mm = get_task_mm(p);
4160 if (!mm)
4161 return 0;
4162 /* We move charges only when we move a owner of the mm */
4163 if (mm->owner == p) {
4164 VM_BUG_ON(mc.from);
4165 VM_BUG_ON(mc.to);
4166 VM_BUG_ON(mc.precharge);
4167 VM_BUG_ON(mc.moved_charge);
4168 VM_BUG_ON(mc.moved_swap);
4169 VM_BUG_ON(mc.moving_task);
4170 mc.from = from;
4171 mc.to = mem;
4172 mc.precharge = 0;
4173 mc.moved_charge = 0;
4174 mc.moved_swap = 0;
4175 mc.moving_task = current;
4177 ret = mem_cgroup_precharge_mc(mm);
4178 if (ret)
4179 mem_cgroup_clear_mc();
4181 mmput(mm);
4183 return ret;
4186 static void mem_cgroup_cancel_attach(struct cgroup_subsys *ss,
4187 struct cgroup *cgroup,
4188 struct task_struct *p,
4189 bool threadgroup)
4191 mem_cgroup_clear_mc();
4194 static int mem_cgroup_move_charge_pte_range(pmd_t *pmd,
4195 unsigned long addr, unsigned long end,
4196 struct mm_walk *walk)
4198 int ret = 0;
4199 struct vm_area_struct *vma = walk->private;
4200 pte_t *pte;
4201 spinlock_t *ptl;
4203 retry:
4204 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
4205 for (; addr != end; addr += PAGE_SIZE) {
4206 pte_t ptent = *(pte++);
4207 union mc_target target;
4208 int type;
4209 struct page *page;
4210 struct page_cgroup *pc;
4211 swp_entry_t ent;
4213 if (!mc.precharge)
4214 break;
4216 type = is_target_pte_for_mc(vma, addr, ptent, &target);
4217 switch (type) {
4218 case MC_TARGET_PAGE:
4219 page = target.page;
4220 if (isolate_lru_page(page))
4221 goto put;
4222 pc = lookup_page_cgroup(page);
4223 if (!mem_cgroup_move_account(pc,
4224 mc.from, mc.to, false)) {
4225 mc.precharge--;
4226 /* we uncharge from mc.from later. */
4227 mc.moved_charge++;
4229 putback_lru_page(page);
4230 put: /* is_target_pte_for_mc() gets the page */
4231 put_page(page);
4232 break;
4233 case MC_TARGET_SWAP:
4234 ent = target.ent;
4235 if (!mem_cgroup_move_swap_account(ent,
4236 mc.from, mc.to, false)) {
4237 mc.precharge--;
4238 /* we fixup refcnts and charges later. */
4239 mc.moved_swap++;
4241 break;
4242 default:
4243 break;
4246 pte_unmap_unlock(pte - 1, ptl);
4247 cond_resched();
4249 if (addr != end) {
4251 * We have consumed all precharges we got in can_attach().
4252 * We try charge one by one, but don't do any additional
4253 * charges to mc.to if we have failed in charge once in attach()
4254 * phase.
4256 ret = mem_cgroup_do_precharge(1);
4257 if (!ret)
4258 goto retry;
4261 return ret;
4264 static void mem_cgroup_move_charge(struct mm_struct *mm)
4266 struct vm_area_struct *vma;
4268 lru_add_drain_all();
4269 down_read(&mm->mmap_sem);
4270 for (vma = mm->mmap; vma; vma = vma->vm_next) {
4271 int ret;
4272 struct mm_walk mem_cgroup_move_charge_walk = {
4273 .pmd_entry = mem_cgroup_move_charge_pte_range,
4274 .mm = mm,
4275 .private = vma,
4277 if (is_vm_hugetlb_page(vma))
4278 continue;
4279 /* TODO: We don't move charges of shmem/tmpfs pages for now. */
4280 if (vma->vm_flags & VM_SHARED)
4281 continue;
4282 ret = walk_page_range(vma->vm_start, vma->vm_end,
4283 &mem_cgroup_move_charge_walk);
4284 if (ret)
4286 * means we have consumed all precharges and failed in
4287 * doing additional charge. Just abandon here.
4289 break;
4291 up_read(&mm->mmap_sem);
4294 static void mem_cgroup_move_task(struct cgroup_subsys *ss,
4295 struct cgroup *cont,
4296 struct cgroup *old_cont,
4297 struct task_struct *p,
4298 bool threadgroup)
4300 struct mm_struct *mm;
4302 if (!mc.to)
4303 /* no need to move charge */
4304 return;
4306 mm = get_task_mm(p);
4307 if (mm) {
4308 mem_cgroup_move_charge(mm);
4309 mmput(mm);
4311 mem_cgroup_clear_mc();
4313 #else /* !CONFIG_MMU */
4314 static int mem_cgroup_can_attach(struct cgroup_subsys *ss,
4315 struct cgroup *cgroup,
4316 struct task_struct *p,
4317 bool threadgroup)
4319 return 0;
4321 static void mem_cgroup_cancel_attach(struct cgroup_subsys *ss,
4322 struct cgroup *cgroup,
4323 struct task_struct *p,
4324 bool threadgroup)
4327 static void mem_cgroup_move_task(struct cgroup_subsys *ss,
4328 struct cgroup *cont,
4329 struct cgroup *old_cont,
4330 struct task_struct *p,
4331 bool threadgroup)
4334 #endif
4336 struct cgroup_subsys mem_cgroup_subsys = {
4337 .name = "memory",
4338 .subsys_id = mem_cgroup_subsys_id,
4339 .create = mem_cgroup_create,
4340 .pre_destroy = mem_cgroup_pre_destroy,
4341 .destroy = mem_cgroup_destroy,
4342 .populate = mem_cgroup_populate,
4343 .can_attach = mem_cgroup_can_attach,
4344 .cancel_attach = mem_cgroup_cancel_attach,
4345 .attach = mem_cgroup_move_task,
4346 .early_init = 0,
4347 .use_id = 1,
4350 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
4352 static int __init disable_swap_account(char *s)
4354 really_do_swap_account = 0;
4355 return 1;
4357 __setup("noswapaccount", disable_swap_account);
4358 #endif