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 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2 of the License, or
12 * (at your option) any later version.
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Public License for more details.
20 #include <linux/res_counter.h>
21 #include <linux/memcontrol.h>
22 #include <linux/cgroup.h>
24 #include <linux/pagemap.h>
25 #include <linux/smp.h>
26 #include <linux/page-flags.h>
27 #include <linux/backing-dev.h>
28 #include <linux/bit_spinlock.h>
29 #include <linux/rcupdate.h>
30 #include <linux/limits.h>
31 #include <linux/mutex.h>
32 #include <linux/slab.h>
33 #include <linux/swap.h>
34 #include <linux/spinlock.h>
36 #include <linux/seq_file.h>
37 #include <linux/vmalloc.h>
38 #include <linux/mm_inline.h>
39 #include <linux/page_cgroup.h>
42 #include <asm/uaccess.h>
44 struct cgroup_subsys mem_cgroup_subsys __read_mostly;
45 #define MEM_CGROUP_RECLAIM_RETRIES 5
47 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
48 /* Turned on only when memory cgroup is enabled && really_do_swap_account = 0 */
49 int do_swap_account __read_mostly;
50 static int really_do_swap_account __initdata = 1; /* for remember boot option*/
52 #define do_swap_account (0)
55 static DEFINE_MUTEX(memcg_tasklist); /* can be hold under cgroup_mutex */
58 * Statistics for memory cgroup.
60 enum mem_cgroup_stat_index {
62 * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss.
64 MEM_CGROUP_STAT_CACHE, /* # of pages charged as cache */
65 MEM_CGROUP_STAT_RSS, /* # of pages charged as rss */
66 MEM_CGROUP_STAT_PGPGIN_COUNT, /* # of pages paged in */
67 MEM_CGROUP_STAT_PGPGOUT_COUNT, /* # of pages paged out */
69 MEM_CGROUP_STAT_NSTATS,
72 struct mem_cgroup_stat_cpu {
73 s64 count[MEM_CGROUP_STAT_NSTATS];
74 } ____cacheline_aligned_in_smp;
76 struct mem_cgroup_stat {
77 struct mem_cgroup_stat_cpu cpustat[0];
81 * For accounting under irq disable, no need for increment preempt count.
83 static inline void __mem_cgroup_stat_add_safe(struct mem_cgroup_stat_cpu *stat,
84 enum mem_cgroup_stat_index idx, int val)
86 stat->count[idx] += val;
89 static s64 mem_cgroup_read_stat(struct mem_cgroup_stat *stat,
90 enum mem_cgroup_stat_index idx)
94 for_each_possible_cpu(cpu)
95 ret += stat->cpustat[cpu].count[idx];
99 static s64 mem_cgroup_local_usage(struct mem_cgroup_stat *stat)
103 ret = mem_cgroup_read_stat(stat, MEM_CGROUP_STAT_CACHE);
104 ret += mem_cgroup_read_stat(stat, MEM_CGROUP_STAT_RSS);
109 * per-zone information in memory controller.
111 struct mem_cgroup_per_zone {
113 * spin_lock to protect the per cgroup LRU
115 struct list_head lists[NR_LRU_LISTS];
116 unsigned long count[NR_LRU_LISTS];
118 struct zone_reclaim_stat reclaim_stat;
120 /* Macro for accessing counter */
121 #define MEM_CGROUP_ZSTAT(mz, idx) ((mz)->count[(idx)])
123 struct mem_cgroup_per_node {
124 struct mem_cgroup_per_zone zoneinfo[MAX_NR_ZONES];
127 struct mem_cgroup_lru_info {
128 struct mem_cgroup_per_node *nodeinfo[MAX_NUMNODES];
132 * The memory controller data structure. The memory controller controls both
133 * page cache and RSS per cgroup. We would eventually like to provide
134 * statistics based on the statistics developed by Rik Van Riel for clock-pro,
135 * to help the administrator determine what knobs to tune.
137 * TODO: Add a water mark for the memory controller. Reclaim will begin when
138 * we hit the water mark. May be even add a low water mark, such that
139 * no reclaim occurs from a cgroup at it's low water mark, this is
140 * a feature that will be implemented much later in the future.
143 struct cgroup_subsys_state css;
145 * the counter to account for memory usage
147 struct res_counter res;
149 * the counter to account for mem+swap usage.
151 struct res_counter memsw;
153 * Per cgroup active and inactive list, similar to the
154 * per zone LRU lists.
156 struct mem_cgroup_lru_info info;
159 protect against reclaim related member.
161 spinlock_t reclaim_param_lock;
163 int prev_priority; /* for recording reclaim priority */
166 * While reclaiming in a hiearchy, we cache the last child we
169 int last_scanned_child;
171 * Should the accounting and control be hierarchical, per subtree?
174 unsigned long last_oom_jiffies;
177 unsigned int swappiness;
180 * statistics. This must be placed at the end of memcg.
182 struct mem_cgroup_stat stat;
186 MEM_CGROUP_CHARGE_TYPE_CACHE = 0,
187 MEM_CGROUP_CHARGE_TYPE_MAPPED,
188 MEM_CGROUP_CHARGE_TYPE_SHMEM, /* used by page migration of shmem */
189 MEM_CGROUP_CHARGE_TYPE_FORCE, /* used by force_empty */
190 MEM_CGROUP_CHARGE_TYPE_SWAPOUT, /* for accounting swapcache */
194 /* only for here (for easy reading.) */
195 #define PCGF_CACHE (1UL << PCG_CACHE)
196 #define PCGF_USED (1UL << PCG_USED)
197 #define PCGF_LOCK (1UL << PCG_LOCK)
198 static const unsigned long
199 pcg_default_flags[NR_CHARGE_TYPE] = {
200 PCGF_CACHE | PCGF_USED | PCGF_LOCK, /* File Cache */
201 PCGF_USED | PCGF_LOCK, /* Anon */
202 PCGF_CACHE | PCGF_USED | PCGF_LOCK, /* Shmem */
206 /* for encoding cft->private value on file */
209 #define MEMFILE_PRIVATE(x, val) (((x) << 16) | (val))
210 #define MEMFILE_TYPE(val) (((val) >> 16) & 0xffff)
211 #define MEMFILE_ATTR(val) ((val) & 0xffff)
213 static void mem_cgroup_get(struct mem_cgroup *mem);
214 static void mem_cgroup_put(struct mem_cgroup *mem);
215 static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem);
217 static void mem_cgroup_charge_statistics(struct mem_cgroup *mem,
218 struct page_cgroup *pc,
221 int val = (charge)? 1 : -1;
222 struct mem_cgroup_stat *stat = &mem->stat;
223 struct mem_cgroup_stat_cpu *cpustat;
226 cpustat = &stat->cpustat[cpu];
227 if (PageCgroupCache(pc))
228 __mem_cgroup_stat_add_safe(cpustat, MEM_CGROUP_STAT_CACHE, val);
230 __mem_cgroup_stat_add_safe(cpustat, MEM_CGROUP_STAT_RSS, val);
233 __mem_cgroup_stat_add_safe(cpustat,
234 MEM_CGROUP_STAT_PGPGIN_COUNT, 1);
236 __mem_cgroup_stat_add_safe(cpustat,
237 MEM_CGROUP_STAT_PGPGOUT_COUNT, 1);
241 static struct mem_cgroup_per_zone *
242 mem_cgroup_zoneinfo(struct mem_cgroup *mem, int nid, int zid)
244 return &mem->info.nodeinfo[nid]->zoneinfo[zid];
247 static struct mem_cgroup_per_zone *
248 page_cgroup_zoneinfo(struct page_cgroup *pc)
250 struct mem_cgroup *mem = pc->mem_cgroup;
251 int nid = page_cgroup_nid(pc);
252 int zid = page_cgroup_zid(pc);
257 return mem_cgroup_zoneinfo(mem, nid, zid);
260 static unsigned long mem_cgroup_get_local_zonestat(struct mem_cgroup *mem,
264 struct mem_cgroup_per_zone *mz;
267 for_each_online_node(nid)
268 for (zid = 0; zid < MAX_NR_ZONES; zid++) {
269 mz = mem_cgroup_zoneinfo(mem, nid, zid);
270 total += MEM_CGROUP_ZSTAT(mz, idx);
275 static struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont)
277 return container_of(cgroup_subsys_state(cont,
278 mem_cgroup_subsys_id), struct mem_cgroup,
282 struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
285 * mm_update_next_owner() may clear mm->owner to NULL
286 * if it races with swapoff, page migration, etc.
287 * So this can be called with p == NULL.
292 return container_of(task_subsys_state(p, mem_cgroup_subsys_id),
293 struct mem_cgroup, css);
296 static struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm)
298 struct mem_cgroup *mem = NULL;
303 * Because we have no locks, mm->owner's may be being moved to other
304 * cgroup. We use css_tryget() here even if this looks
305 * pessimistic (rather than adding locks here).
309 mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
312 } while (!css_tryget(&mem->css));
317 static bool mem_cgroup_is_obsolete(struct mem_cgroup *mem)
321 return css_is_removed(&mem->css);
326 * Call callback function against all cgroup under hierarchy tree.
328 static int mem_cgroup_walk_tree(struct mem_cgroup *root, void *data,
329 int (*func)(struct mem_cgroup *, void *))
331 int found, ret, nextid;
332 struct cgroup_subsys_state *css;
333 struct mem_cgroup *mem;
335 if (!root->use_hierarchy)
336 return (*func)(root, data);
344 css = css_get_next(&mem_cgroup_subsys, nextid, &root->css,
346 if (css && css_tryget(css))
347 mem = container_of(css, struct mem_cgroup, css);
351 ret = (*func)(mem, data);
355 } while (!ret && css);
361 * Following LRU functions are allowed to be used without PCG_LOCK.
362 * Operations are called by routine of global LRU independently from memcg.
363 * What we have to take care of here is validness of pc->mem_cgroup.
365 * Changes to pc->mem_cgroup happens when
368 * In typical case, "charge" is done before add-to-lru. Exception is SwapCache.
369 * It is added to LRU before charge.
370 * If PCG_USED bit is not set, page_cgroup is not added to this private LRU.
371 * When moving account, the page is not on LRU. It's isolated.
374 void mem_cgroup_del_lru_list(struct page *page, enum lru_list lru)
376 struct page_cgroup *pc;
377 struct mem_cgroup *mem;
378 struct mem_cgroup_per_zone *mz;
380 if (mem_cgroup_disabled())
382 pc = lookup_page_cgroup(page);
383 /* can happen while we handle swapcache. */
384 if (list_empty(&pc->lru) || !pc->mem_cgroup)
387 * We don't check PCG_USED bit. It's cleared when the "page" is finally
388 * removed from global LRU.
390 mz = page_cgroup_zoneinfo(pc);
391 mem = pc->mem_cgroup;
392 MEM_CGROUP_ZSTAT(mz, lru) -= 1;
393 list_del_init(&pc->lru);
397 void mem_cgroup_del_lru(struct page *page)
399 mem_cgroup_del_lru_list(page, page_lru(page));
402 void mem_cgroup_rotate_lru_list(struct page *page, enum lru_list lru)
404 struct mem_cgroup_per_zone *mz;
405 struct page_cgroup *pc;
407 if (mem_cgroup_disabled())
410 pc = lookup_page_cgroup(page);
412 * Used bit is set without atomic ops but after smp_wmb().
413 * For making pc->mem_cgroup visible, insert smp_rmb() here.
416 /* unused page is not rotated. */
417 if (!PageCgroupUsed(pc))
419 mz = page_cgroup_zoneinfo(pc);
420 list_move(&pc->lru, &mz->lists[lru]);
423 void mem_cgroup_add_lru_list(struct page *page, enum lru_list lru)
425 struct page_cgroup *pc;
426 struct mem_cgroup_per_zone *mz;
428 if (mem_cgroup_disabled())
430 pc = lookup_page_cgroup(page);
432 * Used bit is set without atomic ops but after smp_wmb().
433 * For making pc->mem_cgroup visible, insert smp_rmb() here.
436 if (!PageCgroupUsed(pc))
439 mz = page_cgroup_zoneinfo(pc);
440 MEM_CGROUP_ZSTAT(mz, lru) += 1;
441 list_add(&pc->lru, &mz->lists[lru]);
445 * At handling SwapCache, pc->mem_cgroup may be changed while it's linked to
446 * lru because the page may.be reused after it's fully uncharged (because of
447 * SwapCache behavior).To handle that, unlink page_cgroup from LRU when charge
448 * it again. This function is only used to charge SwapCache. It's done under
449 * lock_page and expected that zone->lru_lock is never held.
451 static void mem_cgroup_lru_del_before_commit_swapcache(struct page *page)
454 struct zone *zone = page_zone(page);
455 struct page_cgroup *pc = lookup_page_cgroup(page);
457 spin_lock_irqsave(&zone->lru_lock, flags);
459 * Forget old LRU when this page_cgroup is *not* used. This Used bit
460 * is guarded by lock_page() because the page is SwapCache.
462 if (!PageCgroupUsed(pc))
463 mem_cgroup_del_lru_list(page, page_lru(page));
464 spin_unlock_irqrestore(&zone->lru_lock, flags);
467 static void mem_cgroup_lru_add_after_commit_swapcache(struct page *page)
470 struct zone *zone = page_zone(page);
471 struct page_cgroup *pc = lookup_page_cgroup(page);
473 spin_lock_irqsave(&zone->lru_lock, flags);
474 /* link when the page is linked to LRU but page_cgroup isn't */
475 if (PageLRU(page) && list_empty(&pc->lru))
476 mem_cgroup_add_lru_list(page, page_lru(page));
477 spin_unlock_irqrestore(&zone->lru_lock, flags);
481 void mem_cgroup_move_lists(struct page *page,
482 enum lru_list from, enum lru_list to)
484 if (mem_cgroup_disabled())
486 mem_cgroup_del_lru_list(page, from);
487 mem_cgroup_add_lru_list(page, to);
490 int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem)
493 struct mem_cgroup *curr = NULL;
497 curr = try_get_mem_cgroup_from_mm(task->mm);
502 if (curr->use_hierarchy)
503 ret = css_is_ancestor(&curr->css, &mem->css);
511 * prev_priority control...this will be used in memory reclaim path.
513 int mem_cgroup_get_reclaim_priority(struct mem_cgroup *mem)
517 spin_lock(&mem->reclaim_param_lock);
518 prev_priority = mem->prev_priority;
519 spin_unlock(&mem->reclaim_param_lock);
521 return prev_priority;
524 void mem_cgroup_note_reclaim_priority(struct mem_cgroup *mem, int priority)
526 spin_lock(&mem->reclaim_param_lock);
527 if (priority < mem->prev_priority)
528 mem->prev_priority = priority;
529 spin_unlock(&mem->reclaim_param_lock);
532 void mem_cgroup_record_reclaim_priority(struct mem_cgroup *mem, int priority)
534 spin_lock(&mem->reclaim_param_lock);
535 mem->prev_priority = priority;
536 spin_unlock(&mem->reclaim_param_lock);
539 static int calc_inactive_ratio(struct mem_cgroup *memcg, unsigned long *present_pages)
541 unsigned long active;
542 unsigned long inactive;
544 unsigned long inactive_ratio;
546 inactive = mem_cgroup_get_local_zonestat(memcg, LRU_INACTIVE_ANON);
547 active = mem_cgroup_get_local_zonestat(memcg, LRU_ACTIVE_ANON);
549 gb = (inactive + active) >> (30 - PAGE_SHIFT);
551 inactive_ratio = int_sqrt(10 * gb);
556 present_pages[0] = inactive;
557 present_pages[1] = active;
560 return inactive_ratio;
563 int mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg)
565 unsigned long active;
566 unsigned long inactive;
567 unsigned long present_pages[2];
568 unsigned long inactive_ratio;
570 inactive_ratio = calc_inactive_ratio(memcg, present_pages);
572 inactive = present_pages[0];
573 active = present_pages[1];
575 if (inactive * inactive_ratio < active)
581 unsigned long mem_cgroup_zone_nr_pages(struct mem_cgroup *memcg,
585 int nid = zone->zone_pgdat->node_id;
586 int zid = zone_idx(zone);
587 struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid);
589 return MEM_CGROUP_ZSTAT(mz, lru);
592 struct zone_reclaim_stat *mem_cgroup_get_reclaim_stat(struct mem_cgroup *memcg,
595 int nid = zone->zone_pgdat->node_id;
596 int zid = zone_idx(zone);
597 struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid);
599 return &mz->reclaim_stat;
602 struct zone_reclaim_stat *
603 mem_cgroup_get_reclaim_stat_from_page(struct page *page)
605 struct page_cgroup *pc;
606 struct mem_cgroup_per_zone *mz;
608 if (mem_cgroup_disabled())
611 pc = lookup_page_cgroup(page);
613 * Used bit is set without atomic ops but after smp_wmb().
614 * For making pc->mem_cgroup visible, insert smp_rmb() here.
617 if (!PageCgroupUsed(pc))
620 mz = page_cgroup_zoneinfo(pc);
624 return &mz->reclaim_stat;
627 unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
628 struct list_head *dst,
629 unsigned long *scanned, int order,
630 int mode, struct zone *z,
631 struct mem_cgroup *mem_cont,
632 int active, int file)
634 unsigned long nr_taken = 0;
638 struct list_head *src;
639 struct page_cgroup *pc, *tmp;
640 int nid = z->zone_pgdat->node_id;
641 int zid = zone_idx(z);
642 struct mem_cgroup_per_zone *mz;
643 int lru = LRU_FILE * !!file + !!active;
646 mz = mem_cgroup_zoneinfo(mem_cont, nid, zid);
647 src = &mz->lists[lru];
650 list_for_each_entry_safe_reverse(pc, tmp, src, lru) {
651 if (scan >= nr_to_scan)
655 if (unlikely(!PageCgroupUsed(pc)))
657 if (unlikely(!PageLRU(page)))
661 if (__isolate_lru_page(page, mode, file) == 0) {
662 list_move(&page->lru, dst);
671 #define mem_cgroup_from_res_counter(counter, member) \
672 container_of(counter, struct mem_cgroup, member)
674 static bool mem_cgroup_check_under_limit(struct mem_cgroup *mem)
676 if (do_swap_account) {
677 if (res_counter_check_under_limit(&mem->res) &&
678 res_counter_check_under_limit(&mem->memsw))
681 if (res_counter_check_under_limit(&mem->res))
686 static unsigned int get_swappiness(struct mem_cgroup *memcg)
688 struct cgroup *cgrp = memcg->css.cgroup;
689 unsigned int swappiness;
692 if (cgrp->parent == NULL)
693 return vm_swappiness;
695 spin_lock(&memcg->reclaim_param_lock);
696 swappiness = memcg->swappiness;
697 spin_unlock(&memcg->reclaim_param_lock);
702 static int mem_cgroup_count_children_cb(struct mem_cgroup *mem, void *data)
710 * mem_cgroup_print_mem_info: Called from OOM with tasklist_lock held in read mode.
711 * @memcg: The memory cgroup that went over limit
712 * @p: Task that is going to be killed
714 * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is
717 void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
719 struct cgroup *task_cgrp;
720 struct cgroup *mem_cgrp;
722 * Need a buffer in BSS, can't rely on allocations. The code relies
723 * on the assumption that OOM is serialized for memory controller.
724 * If this assumption is broken, revisit this code.
726 static char memcg_name[PATH_MAX];
735 mem_cgrp = memcg->css.cgroup;
736 task_cgrp = task_cgroup(p, mem_cgroup_subsys_id);
738 ret = cgroup_path(task_cgrp, memcg_name, PATH_MAX);
741 * Unfortunately, we are unable to convert to a useful name
742 * But we'll still print out the usage information
749 printk(KERN_INFO "Task in %s killed", memcg_name);
752 ret = cgroup_path(mem_cgrp, memcg_name, PATH_MAX);
760 * Continues from above, so we don't need an KERN_ level
762 printk(KERN_CONT " as a result of limit of %s\n", memcg_name);
765 printk(KERN_INFO "memory: usage %llukB, limit %llukB, failcnt %llu\n",
766 res_counter_read_u64(&memcg->res, RES_USAGE) >> 10,
767 res_counter_read_u64(&memcg->res, RES_LIMIT) >> 10,
768 res_counter_read_u64(&memcg->res, RES_FAILCNT));
769 printk(KERN_INFO "memory+swap: usage %llukB, limit %llukB, "
771 res_counter_read_u64(&memcg->memsw, RES_USAGE) >> 10,
772 res_counter_read_u64(&memcg->memsw, RES_LIMIT) >> 10,
773 res_counter_read_u64(&memcg->memsw, RES_FAILCNT));
777 * This function returns the number of memcg under hierarchy tree. Returns
778 * 1(self count) if no children.
780 static int mem_cgroup_count_children(struct mem_cgroup *mem)
783 mem_cgroup_walk_tree(mem, &num, mem_cgroup_count_children_cb);
788 * Visit the first child (need not be the first child as per the ordering
789 * of the cgroup list, since we track last_scanned_child) of @mem and use
790 * that to reclaim free pages from.
792 static struct mem_cgroup *
793 mem_cgroup_select_victim(struct mem_cgroup *root_mem)
795 struct mem_cgroup *ret = NULL;
796 struct cgroup_subsys_state *css;
799 if (!root_mem->use_hierarchy) {
800 css_get(&root_mem->css);
806 nextid = root_mem->last_scanned_child + 1;
807 css = css_get_next(&mem_cgroup_subsys, nextid, &root_mem->css,
809 if (css && css_tryget(css))
810 ret = container_of(css, struct mem_cgroup, css);
813 /* Updates scanning parameter */
814 spin_lock(&root_mem->reclaim_param_lock);
816 /* this means start scan from ID:1 */
817 root_mem->last_scanned_child = 0;
819 root_mem->last_scanned_child = found;
820 spin_unlock(&root_mem->reclaim_param_lock);
827 * Scan the hierarchy if needed to reclaim memory. We remember the last child
828 * we reclaimed from, so that we don't end up penalizing one child extensively
829 * based on its position in the children list.
831 * root_mem is the original ancestor that we've been reclaim from.
833 * We give up and return to the caller when we visit root_mem twice.
834 * (other groups can be removed while we're walking....)
836 * If shrink==true, for avoiding to free too much, this returns immedieately.
838 static int mem_cgroup_hierarchical_reclaim(struct mem_cgroup *root_mem,
839 gfp_t gfp_mask, bool noswap, bool shrink)
841 struct mem_cgroup *victim;
846 victim = mem_cgroup_select_victim(root_mem);
847 if (victim == root_mem)
849 if (!mem_cgroup_local_usage(&victim->stat)) {
850 /* this cgroup's local usage == 0 */
851 css_put(&victim->css);
854 /* we use swappiness of local cgroup */
855 ret = try_to_free_mem_cgroup_pages(victim, gfp_mask, noswap,
856 get_swappiness(victim));
857 css_put(&victim->css);
859 * At shrinking usage, we can't check we should stop here or
860 * reclaim more. It's depends on callers. last_scanned_child
861 * will work enough for keeping fairness under tree.
866 if (mem_cgroup_check_under_limit(root_mem))
872 bool mem_cgroup_oom_called(struct task_struct *task)
875 struct mem_cgroup *mem;
876 struct mm_struct *mm;
882 mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
883 if (mem && time_before(jiffies, mem->last_oom_jiffies + HZ/10))
889 static int record_last_oom_cb(struct mem_cgroup *mem, void *data)
891 mem->last_oom_jiffies = jiffies;
895 static void record_last_oom(struct mem_cgroup *mem)
897 mem_cgroup_walk_tree(mem, NULL, record_last_oom_cb);
902 * Unlike exported interface, "oom" parameter is added. if oom==true,
903 * oom-killer can be invoked.
905 static int __mem_cgroup_try_charge(struct mm_struct *mm,
906 gfp_t gfp_mask, struct mem_cgroup **memcg,
909 struct mem_cgroup *mem, *mem_over_limit;
910 int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
911 struct res_counter *fail_res;
913 if (unlikely(test_thread_flag(TIF_MEMDIE))) {
914 /* Don't account this! */
920 * We always charge the cgroup the mm_struct belongs to.
921 * The mm_struct's mem_cgroup changes on task migration if the
922 * thread group leader migrates. It's possible that mm is not
923 * set, if so charge the init_mm (happens for pagecache usage).
927 mem = try_get_mem_cgroup_from_mm(mm);
935 VM_BUG_ON(mem_cgroup_is_obsolete(mem));
941 ret = res_counter_charge(&mem->res, PAGE_SIZE, &fail_res);
943 if (!do_swap_account)
945 ret = res_counter_charge(&mem->memsw, PAGE_SIZE,
949 /* mem+swap counter fails */
950 res_counter_uncharge(&mem->res, PAGE_SIZE);
952 mem_over_limit = mem_cgroup_from_res_counter(fail_res,
955 /* mem counter fails */
956 mem_over_limit = mem_cgroup_from_res_counter(fail_res,
959 if (!(gfp_mask & __GFP_WAIT))
962 ret = mem_cgroup_hierarchical_reclaim(mem_over_limit, gfp_mask,
968 * try_to_free_mem_cgroup_pages() might not give us a full
969 * picture of reclaim. Some pages are reclaimed and might be
970 * moved to swap cache or just unmapped from the cgroup.
971 * Check the limit again to see if the reclaim reduced the
972 * current usage of the cgroup before giving up
975 if (mem_cgroup_check_under_limit(mem_over_limit))
980 mutex_lock(&memcg_tasklist);
981 mem_cgroup_out_of_memory(mem_over_limit, gfp_mask);
982 mutex_unlock(&memcg_tasklist);
983 record_last_oom(mem_over_limit);
996 * A helper function to get mem_cgroup from ID. must be called under
997 * rcu_read_lock(). The caller must check css_is_removed() or some if
998 * it's concern. (dropping refcnt from swap can be called against removed
1001 static struct mem_cgroup *mem_cgroup_lookup(unsigned short id)
1003 struct cgroup_subsys_state *css;
1005 /* ID 0 is unused ID */
1008 css = css_lookup(&mem_cgroup_subsys, id);
1011 return container_of(css, struct mem_cgroup, css);
1014 static struct mem_cgroup *try_get_mem_cgroup_from_swapcache(struct page *page)
1016 struct mem_cgroup *mem;
1017 struct page_cgroup *pc;
1021 VM_BUG_ON(!PageLocked(page));
1023 if (!PageSwapCache(page))
1026 pc = lookup_page_cgroup(page);
1028 * Used bit of swapcache is solid under page lock.
1030 if (PageCgroupUsed(pc)) {
1031 mem = pc->mem_cgroup;
1032 if (mem && !css_tryget(&mem->css))
1035 ent.val = page_private(page);
1036 id = lookup_swap_cgroup(ent);
1038 mem = mem_cgroup_lookup(id);
1039 if (mem && !css_tryget(&mem->css))
1047 * commit a charge got by __mem_cgroup_try_charge() and makes page_cgroup to be
1048 * USED state. If already USED, uncharge and return.
1051 static void __mem_cgroup_commit_charge(struct mem_cgroup *mem,
1052 struct page_cgroup *pc,
1053 enum charge_type ctype)
1055 /* try_charge() can return NULL to *memcg, taking care of it. */
1059 lock_page_cgroup(pc);
1060 if (unlikely(PageCgroupUsed(pc))) {
1061 unlock_page_cgroup(pc);
1062 res_counter_uncharge(&mem->res, PAGE_SIZE);
1063 if (do_swap_account)
1064 res_counter_uncharge(&mem->memsw, PAGE_SIZE);
1068 pc->mem_cgroup = mem;
1070 pc->flags = pcg_default_flags[ctype];
1072 mem_cgroup_charge_statistics(mem, pc, true);
1074 unlock_page_cgroup(pc);
1078 * mem_cgroup_move_account - move account of the page
1079 * @pc: page_cgroup of the page.
1080 * @from: mem_cgroup which the page is moved from.
1081 * @to: mem_cgroup which the page is moved to. @from != @to.
1083 * The caller must confirm following.
1084 * - page is not on LRU (isolate_page() is useful.)
1086 * returns 0 at success,
1087 * returns -EBUSY when lock is busy or "pc" is unstable.
1089 * This function does "uncharge" from old cgroup but doesn't do "charge" to
1090 * new cgroup. It should be done by a caller.
1093 static int mem_cgroup_move_account(struct page_cgroup *pc,
1094 struct mem_cgroup *from, struct mem_cgroup *to)
1096 struct mem_cgroup_per_zone *from_mz, *to_mz;
1100 VM_BUG_ON(from == to);
1101 VM_BUG_ON(PageLRU(pc->page));
1103 nid = page_cgroup_nid(pc);
1104 zid = page_cgroup_zid(pc);
1105 from_mz = mem_cgroup_zoneinfo(from, nid, zid);
1106 to_mz = mem_cgroup_zoneinfo(to, nid, zid);
1108 if (!trylock_page_cgroup(pc))
1111 if (!PageCgroupUsed(pc))
1114 if (pc->mem_cgroup != from)
1117 res_counter_uncharge(&from->res, PAGE_SIZE);
1118 mem_cgroup_charge_statistics(from, pc, false);
1119 if (do_swap_account)
1120 res_counter_uncharge(&from->memsw, PAGE_SIZE);
1121 css_put(&from->css);
1124 pc->mem_cgroup = to;
1125 mem_cgroup_charge_statistics(to, pc, true);
1128 unlock_page_cgroup(pc);
1133 * move charges to its parent.
1136 static int mem_cgroup_move_parent(struct page_cgroup *pc,
1137 struct mem_cgroup *child,
1140 struct page *page = pc->page;
1141 struct cgroup *cg = child->css.cgroup;
1142 struct cgroup *pcg = cg->parent;
1143 struct mem_cgroup *parent;
1151 parent = mem_cgroup_from_cont(pcg);
1154 ret = __mem_cgroup_try_charge(NULL, gfp_mask, &parent, false);
1158 if (!get_page_unless_zero(page)) {
1163 ret = isolate_lru_page(page);
1168 ret = mem_cgroup_move_account(pc, child, parent);
1170 putback_lru_page(page);
1173 /* drop extra refcnt by try_charge() */
1174 css_put(&parent->css);
1181 /* drop extra refcnt by try_charge() */
1182 css_put(&parent->css);
1183 /* uncharge if move fails */
1184 res_counter_uncharge(&parent->res, PAGE_SIZE);
1185 if (do_swap_account)
1186 res_counter_uncharge(&parent->memsw, PAGE_SIZE);
1191 * Charge the memory controller for page usage.
1193 * 0 if the charge was successful
1194 * < 0 if the cgroup is over its limit
1196 static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm,
1197 gfp_t gfp_mask, enum charge_type ctype,
1198 struct mem_cgroup *memcg)
1200 struct mem_cgroup *mem;
1201 struct page_cgroup *pc;
1204 pc = lookup_page_cgroup(page);
1205 /* can happen at boot */
1211 ret = __mem_cgroup_try_charge(mm, gfp_mask, &mem, true);
1215 __mem_cgroup_commit_charge(mem, pc, ctype);
1219 int mem_cgroup_newpage_charge(struct page *page,
1220 struct mm_struct *mm, gfp_t gfp_mask)
1222 if (mem_cgroup_disabled())
1224 if (PageCompound(page))
1227 * If already mapped, we don't have to account.
1228 * If page cache, page->mapping has address_space.
1229 * But page->mapping may have out-of-use anon_vma pointer,
1230 * detecit it by PageAnon() check. newly-mapped-anon's page->mapping
1233 if (page_mapped(page) || (page->mapping && !PageAnon(page)))
1237 return mem_cgroup_charge_common(page, mm, gfp_mask,
1238 MEM_CGROUP_CHARGE_TYPE_MAPPED, NULL);
1242 __mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr,
1243 enum charge_type ctype);
1245 int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
1248 struct mem_cgroup *mem = NULL;
1251 if (mem_cgroup_disabled())
1253 if (PageCompound(page))
1256 * Corner case handling. This is called from add_to_page_cache()
1257 * in usual. But some FS (shmem) precharges this page before calling it
1258 * and call add_to_page_cache() with GFP_NOWAIT.
1260 * For GFP_NOWAIT case, the page may be pre-charged before calling
1261 * add_to_page_cache(). (See shmem.c) check it here and avoid to call
1262 * charge twice. (It works but has to pay a bit larger cost.)
1263 * And when the page is SwapCache, it should take swap information
1264 * into account. This is under lock_page() now.
1266 if (!(gfp_mask & __GFP_WAIT)) {
1267 struct page_cgroup *pc;
1270 pc = lookup_page_cgroup(page);
1273 lock_page_cgroup(pc);
1274 if (PageCgroupUsed(pc)) {
1275 unlock_page_cgroup(pc);
1278 unlock_page_cgroup(pc);
1281 if (unlikely(!mm && !mem))
1284 if (page_is_file_cache(page))
1285 return mem_cgroup_charge_common(page, mm, gfp_mask,
1286 MEM_CGROUP_CHARGE_TYPE_CACHE, NULL);
1289 if (PageSwapCache(page)) {
1290 ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &mem);
1292 __mem_cgroup_commit_charge_swapin(page, mem,
1293 MEM_CGROUP_CHARGE_TYPE_SHMEM);
1295 ret = mem_cgroup_charge_common(page, mm, gfp_mask,
1296 MEM_CGROUP_CHARGE_TYPE_SHMEM, mem);
1302 * While swap-in, try_charge -> commit or cancel, the page is locked.
1303 * And when try_charge() successfully returns, one refcnt to memcg without
1304 * struct page_cgroup is aquired. This refcnt will be cumsumed by
1305 * "commit()" or removed by "cancel()"
1307 int mem_cgroup_try_charge_swapin(struct mm_struct *mm,
1309 gfp_t mask, struct mem_cgroup **ptr)
1311 struct mem_cgroup *mem;
1314 if (mem_cgroup_disabled())
1317 if (!do_swap_account)
1320 * A racing thread's fault, or swapoff, may have already updated
1321 * the pte, and even removed page from swap cache: return success
1322 * to go on to do_swap_page()'s pte_same() test, which should fail.
1324 if (!PageSwapCache(page))
1326 mem = try_get_mem_cgroup_from_swapcache(page);
1330 ret = __mem_cgroup_try_charge(NULL, mask, ptr, true);
1331 /* drop extra refcnt from tryget */
1337 return __mem_cgroup_try_charge(mm, mask, ptr, true);
1341 __mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr,
1342 enum charge_type ctype)
1344 struct page_cgroup *pc;
1346 if (mem_cgroup_disabled())
1350 pc = lookup_page_cgroup(page);
1351 mem_cgroup_lru_del_before_commit_swapcache(page);
1352 __mem_cgroup_commit_charge(ptr, pc, ctype);
1353 mem_cgroup_lru_add_after_commit_swapcache(page);
1355 * Now swap is on-memory. This means this page may be
1356 * counted both as mem and swap....double count.
1357 * Fix it by uncharging from memsw. Basically, this SwapCache is stable
1358 * under lock_page(). But in do_swap_page()::memory.c, reuse_swap_page()
1359 * may call delete_from_swap_cache() before reach here.
1361 if (do_swap_account && PageSwapCache(page)) {
1362 swp_entry_t ent = {.val = page_private(page)};
1364 struct mem_cgroup *memcg;
1366 id = swap_cgroup_record(ent, 0);
1368 memcg = mem_cgroup_lookup(id);
1371 * This recorded memcg can be obsolete one. So, avoid
1372 * calling css_tryget
1374 res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
1375 mem_cgroup_put(memcg);
1379 /* add this page(page_cgroup) to the LRU we want. */
1383 void mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr)
1385 __mem_cgroup_commit_charge_swapin(page, ptr,
1386 MEM_CGROUP_CHARGE_TYPE_MAPPED);
1389 void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *mem)
1391 if (mem_cgroup_disabled())
1395 res_counter_uncharge(&mem->res, PAGE_SIZE);
1396 if (do_swap_account)
1397 res_counter_uncharge(&mem->memsw, PAGE_SIZE);
1403 * uncharge if !page_mapped(page)
1405 static struct mem_cgroup *
1406 __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
1408 struct page_cgroup *pc;
1409 struct mem_cgroup *mem = NULL;
1410 struct mem_cgroup_per_zone *mz;
1412 if (mem_cgroup_disabled())
1415 if (PageSwapCache(page))
1419 * Check if our page_cgroup is valid
1421 pc = lookup_page_cgroup(page);
1422 if (unlikely(!pc || !PageCgroupUsed(pc)))
1425 lock_page_cgroup(pc);
1427 mem = pc->mem_cgroup;
1429 if (!PageCgroupUsed(pc))
1433 case MEM_CGROUP_CHARGE_TYPE_MAPPED:
1434 if (page_mapped(page))
1437 case MEM_CGROUP_CHARGE_TYPE_SWAPOUT:
1438 if (!PageAnon(page)) { /* Shared memory */
1439 if (page->mapping && !page_is_file_cache(page))
1441 } else if (page_mapped(page)) /* Anon */
1448 res_counter_uncharge(&mem->res, PAGE_SIZE);
1449 if (do_swap_account && (ctype != MEM_CGROUP_CHARGE_TYPE_SWAPOUT))
1450 res_counter_uncharge(&mem->memsw, PAGE_SIZE);
1451 mem_cgroup_charge_statistics(mem, pc, false);
1453 ClearPageCgroupUsed(pc);
1455 * pc->mem_cgroup is not cleared here. It will be accessed when it's
1456 * freed from LRU. This is safe because uncharged page is expected not
1457 * to be reused (freed soon). Exception is SwapCache, it's handled by
1458 * special functions.
1461 mz = page_cgroup_zoneinfo(pc);
1462 unlock_page_cgroup(pc);
1464 /* at swapout, this memcg will be accessed to record to swap */
1465 if (ctype != MEM_CGROUP_CHARGE_TYPE_SWAPOUT)
1471 unlock_page_cgroup(pc);
1475 void mem_cgroup_uncharge_page(struct page *page)
1478 if (page_mapped(page))
1480 if (page->mapping && !PageAnon(page))
1482 __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_MAPPED);
1485 void mem_cgroup_uncharge_cache_page(struct page *page)
1487 VM_BUG_ON(page_mapped(page));
1488 VM_BUG_ON(page->mapping);
1489 __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE);
1493 * called from __delete_from_swap_cache() and drop "page" account.
1494 * memcg information is recorded to swap_cgroup of "ent"
1496 void mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent)
1498 struct mem_cgroup *memcg;
1500 memcg = __mem_cgroup_uncharge_common(page,
1501 MEM_CGROUP_CHARGE_TYPE_SWAPOUT);
1502 /* record memcg information */
1503 if (do_swap_account && memcg) {
1504 swap_cgroup_record(ent, css_id(&memcg->css));
1505 mem_cgroup_get(memcg);
1508 css_put(&memcg->css);
1511 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
1513 * called from swap_entry_free(). remove record in swap_cgroup and
1514 * uncharge "memsw" account.
1516 void mem_cgroup_uncharge_swap(swp_entry_t ent)
1518 struct mem_cgroup *memcg;
1521 if (!do_swap_account)
1524 id = swap_cgroup_record(ent, 0);
1526 memcg = mem_cgroup_lookup(id);
1529 * We uncharge this because swap is freed.
1530 * This memcg can be obsolete one. We avoid calling css_tryget
1532 res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
1533 mem_cgroup_put(memcg);
1540 * Before starting migration, account PAGE_SIZE to mem_cgroup that the old
1543 int mem_cgroup_prepare_migration(struct page *page, struct mem_cgroup **ptr)
1545 struct page_cgroup *pc;
1546 struct mem_cgroup *mem = NULL;
1549 if (mem_cgroup_disabled())
1552 pc = lookup_page_cgroup(page);
1553 lock_page_cgroup(pc);
1554 if (PageCgroupUsed(pc)) {
1555 mem = pc->mem_cgroup;
1558 unlock_page_cgroup(pc);
1561 ret = __mem_cgroup_try_charge(NULL, GFP_KERNEL, &mem, false);
1568 /* remove redundant charge if migration failed*/
1569 void mem_cgroup_end_migration(struct mem_cgroup *mem,
1570 struct page *oldpage, struct page *newpage)
1572 struct page *target, *unused;
1573 struct page_cgroup *pc;
1574 enum charge_type ctype;
1579 /* at migration success, oldpage->mapping is NULL. */
1580 if (oldpage->mapping) {
1588 if (PageAnon(target))
1589 ctype = MEM_CGROUP_CHARGE_TYPE_MAPPED;
1590 else if (page_is_file_cache(target))
1591 ctype = MEM_CGROUP_CHARGE_TYPE_CACHE;
1593 ctype = MEM_CGROUP_CHARGE_TYPE_SHMEM;
1595 /* unused page is not on radix-tree now. */
1597 __mem_cgroup_uncharge_common(unused, ctype);
1599 pc = lookup_page_cgroup(target);
1601 * __mem_cgroup_commit_charge() check PCG_USED bit of page_cgroup.
1602 * So, double-counting is effectively avoided.
1604 __mem_cgroup_commit_charge(mem, pc, ctype);
1607 * Both of oldpage and newpage are still under lock_page().
1608 * Then, we don't have to care about race in radix-tree.
1609 * But we have to be careful that this page is unmapped or not.
1611 * There is a case for !page_mapped(). At the start of
1612 * migration, oldpage was mapped. But now, it's zapped.
1613 * But we know *target* page is not freed/reused under us.
1614 * mem_cgroup_uncharge_page() does all necessary checks.
1616 if (ctype == MEM_CGROUP_CHARGE_TYPE_MAPPED)
1617 mem_cgroup_uncharge_page(target);
1621 * A call to try to shrink memory usage under specified resource controller.
1622 * This is typically used for page reclaiming for shmem for reducing side
1623 * effect of page allocation from shmem, which is used by some mem_cgroup.
1625 int mem_cgroup_shrink_usage(struct page *page,
1626 struct mm_struct *mm,
1629 struct mem_cgroup *mem = NULL;
1631 int retry = MEM_CGROUP_RECLAIM_RETRIES;
1633 if (mem_cgroup_disabled())
1636 mem = try_get_mem_cgroup_from_swapcache(page);
1638 mem = try_get_mem_cgroup_from_mm(mm);
1643 progress = mem_cgroup_hierarchical_reclaim(mem,
1644 gfp_mask, true, false);
1645 progress += mem_cgroup_check_under_limit(mem);
1646 } while (!progress && --retry);
1654 static DEFINE_MUTEX(set_limit_mutex);
1656 static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
1657 unsigned long long val)
1663 int children = mem_cgroup_count_children(memcg);
1664 u64 curusage, oldusage;
1667 * For keeping hierarchical_reclaim simple, how long we should retry
1668 * is depends on callers. We set our retry-count to be function
1669 * of # of children which we should visit in this loop.
1671 retry_count = MEM_CGROUP_RECLAIM_RETRIES * children;
1673 oldusage = res_counter_read_u64(&memcg->res, RES_USAGE);
1675 while (retry_count) {
1676 if (signal_pending(current)) {
1681 * Rather than hide all in some function, I do this in
1682 * open coded manner. You see what this really does.
1683 * We have to guarantee mem->res.limit < mem->memsw.limit.
1685 mutex_lock(&set_limit_mutex);
1686 memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
1687 if (memswlimit < val) {
1689 mutex_unlock(&set_limit_mutex);
1692 ret = res_counter_set_limit(&memcg->res, val);
1693 mutex_unlock(&set_limit_mutex);
1698 progress = mem_cgroup_hierarchical_reclaim(memcg, GFP_KERNEL,
1700 curusage = res_counter_read_u64(&memcg->res, RES_USAGE);
1701 /* Usage is reduced ? */
1702 if (curusage >= oldusage)
1705 oldusage = curusage;
1711 int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
1712 unsigned long long val)
1715 u64 memlimit, oldusage, curusage;
1716 int children = mem_cgroup_count_children(memcg);
1719 if (!do_swap_account)
1721 /* see mem_cgroup_resize_res_limit */
1722 retry_count = children * MEM_CGROUP_RECLAIM_RETRIES;
1723 oldusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
1724 while (retry_count) {
1725 if (signal_pending(current)) {
1730 * Rather than hide all in some function, I do this in
1731 * open coded manner. You see what this really does.
1732 * We have to guarantee mem->res.limit < mem->memsw.limit.
1734 mutex_lock(&set_limit_mutex);
1735 memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT);
1736 if (memlimit > val) {
1738 mutex_unlock(&set_limit_mutex);
1741 ret = res_counter_set_limit(&memcg->memsw, val);
1742 mutex_unlock(&set_limit_mutex);
1747 mem_cgroup_hierarchical_reclaim(memcg, GFP_KERNEL, true, true);
1748 curusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
1749 /* Usage is reduced ? */
1750 if (curusage >= oldusage)
1753 oldusage = curusage;
1759 * This routine traverse page_cgroup in given list and drop them all.
1760 * *And* this routine doesn't reclaim page itself, just removes page_cgroup.
1762 static int mem_cgroup_force_empty_list(struct mem_cgroup *mem,
1763 int node, int zid, enum lru_list lru)
1766 struct mem_cgroup_per_zone *mz;
1767 struct page_cgroup *pc, *busy;
1768 unsigned long flags, loop;
1769 struct list_head *list;
1772 zone = &NODE_DATA(node)->node_zones[zid];
1773 mz = mem_cgroup_zoneinfo(mem, node, zid);
1774 list = &mz->lists[lru];
1776 loop = MEM_CGROUP_ZSTAT(mz, lru);
1777 /* give some margin against EBUSY etc...*/
1782 spin_lock_irqsave(&zone->lru_lock, flags);
1783 if (list_empty(list)) {
1784 spin_unlock_irqrestore(&zone->lru_lock, flags);
1787 pc = list_entry(list->prev, struct page_cgroup, lru);
1789 list_move(&pc->lru, list);
1791 spin_unlock_irqrestore(&zone->lru_lock, flags);
1794 spin_unlock_irqrestore(&zone->lru_lock, flags);
1796 ret = mem_cgroup_move_parent(pc, mem, GFP_KERNEL);
1800 if (ret == -EBUSY || ret == -EINVAL) {
1801 /* found lock contention or "pc" is obsolete. */
1808 if (!ret && !list_empty(list))
1814 * make mem_cgroup's charge to be 0 if there is no task.
1815 * This enables deleting this mem_cgroup.
1817 static int mem_cgroup_force_empty(struct mem_cgroup *mem, bool free_all)
1820 int node, zid, shrink;
1821 int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
1822 struct cgroup *cgrp = mem->css.cgroup;
1827 /* should free all ? */
1831 while (mem->res.usage > 0) {
1833 if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children))
1836 if (signal_pending(current))
1838 /* This is for making all *used* pages to be on LRU. */
1839 lru_add_drain_all();
1841 for_each_node_state(node, N_HIGH_MEMORY) {
1842 for (zid = 0; !ret && zid < MAX_NR_ZONES; zid++) {
1845 ret = mem_cgroup_force_empty_list(mem,
1854 /* it seems parent cgroup doesn't have enough mem */
1865 /* returns EBUSY if there is a task or if we come here twice. */
1866 if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children) || shrink) {
1870 /* we call try-to-free pages for make this cgroup empty */
1871 lru_add_drain_all();
1872 /* try to free all pages in this cgroup */
1874 while (nr_retries && mem->res.usage > 0) {
1877 if (signal_pending(current)) {
1881 progress = try_to_free_mem_cgroup_pages(mem, GFP_KERNEL,
1882 false, get_swappiness(mem));
1885 /* maybe some writeback is necessary */
1886 congestion_wait(WRITE, HZ/10);
1891 /* try move_account...there may be some *locked* pages. */
1898 int mem_cgroup_force_empty_write(struct cgroup *cont, unsigned int event)
1900 return mem_cgroup_force_empty(mem_cgroup_from_cont(cont), true);
1904 static u64 mem_cgroup_hierarchy_read(struct cgroup *cont, struct cftype *cft)
1906 return mem_cgroup_from_cont(cont)->use_hierarchy;
1909 static int mem_cgroup_hierarchy_write(struct cgroup *cont, struct cftype *cft,
1913 struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
1914 struct cgroup *parent = cont->parent;
1915 struct mem_cgroup *parent_mem = NULL;
1918 parent_mem = mem_cgroup_from_cont(parent);
1922 * If parent's use_hiearchy is set, we can't make any modifications
1923 * in the child subtrees. If it is unset, then the change can
1924 * occur, provided the current cgroup has no children.
1926 * For the root cgroup, parent_mem is NULL, we allow value to be
1927 * set if there are no children.
1929 if ((!parent_mem || !parent_mem->use_hierarchy) &&
1930 (val == 1 || val == 0)) {
1931 if (list_empty(&cont->children))
1932 mem->use_hierarchy = val;
1942 static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft)
1944 struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
1948 type = MEMFILE_TYPE(cft->private);
1949 name = MEMFILE_ATTR(cft->private);
1952 val = res_counter_read_u64(&mem->res, name);
1955 if (do_swap_account)
1956 val = res_counter_read_u64(&mem->memsw, name);
1965 * The user of this function is...
1968 static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
1971 struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
1973 unsigned long long val;
1976 type = MEMFILE_TYPE(cft->private);
1977 name = MEMFILE_ATTR(cft->private);
1980 /* This function does all necessary parse...reuse it */
1981 ret = res_counter_memparse_write_strategy(buffer, &val);
1985 ret = mem_cgroup_resize_limit(memcg, val);
1987 ret = mem_cgroup_resize_memsw_limit(memcg, val);
1990 ret = -EINVAL; /* should be BUG() ? */
1996 static void memcg_get_hierarchical_limit(struct mem_cgroup *memcg,
1997 unsigned long long *mem_limit, unsigned long long *memsw_limit)
1999 struct cgroup *cgroup;
2000 unsigned long long min_limit, min_memsw_limit, tmp;
2002 min_limit = res_counter_read_u64(&memcg->res, RES_LIMIT);
2003 min_memsw_limit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
2004 cgroup = memcg->css.cgroup;
2005 if (!memcg->use_hierarchy)
2008 while (cgroup->parent) {
2009 cgroup = cgroup->parent;
2010 memcg = mem_cgroup_from_cont(cgroup);
2011 if (!memcg->use_hierarchy)
2013 tmp = res_counter_read_u64(&memcg->res, RES_LIMIT);
2014 min_limit = min(min_limit, tmp);
2015 tmp = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
2016 min_memsw_limit = min(min_memsw_limit, tmp);
2019 *mem_limit = min_limit;
2020 *memsw_limit = min_memsw_limit;
2024 static int mem_cgroup_reset(struct cgroup *cont, unsigned int event)
2026 struct mem_cgroup *mem;
2029 mem = mem_cgroup_from_cont(cont);
2030 type = MEMFILE_TYPE(event);
2031 name = MEMFILE_ATTR(event);
2035 res_counter_reset_max(&mem->res);
2037 res_counter_reset_max(&mem->memsw);
2041 res_counter_reset_failcnt(&mem->res);
2043 res_counter_reset_failcnt(&mem->memsw);
2050 /* For read statistics */
2064 struct mcs_total_stat {
2065 s64 stat[NR_MCS_STAT];
2071 } memcg_stat_strings[NR_MCS_STAT] = {
2072 {"cache", "total_cache"},
2073 {"rss", "total_rss"},
2074 {"pgpgin", "total_pgpgin"},
2075 {"pgpgout", "total_pgpgout"},
2076 {"inactive_anon", "total_inactive_anon"},
2077 {"active_anon", "total_active_anon"},
2078 {"inactive_file", "total_inactive_file"},
2079 {"active_file", "total_active_file"},
2080 {"unevictable", "total_unevictable"}
2084 static int mem_cgroup_get_local_stat(struct mem_cgroup *mem, void *data)
2086 struct mcs_total_stat *s = data;
2090 val = mem_cgroup_read_stat(&mem->stat, MEM_CGROUP_STAT_CACHE);
2091 s->stat[MCS_CACHE] += val * PAGE_SIZE;
2092 val = mem_cgroup_read_stat(&mem->stat, MEM_CGROUP_STAT_RSS);
2093 s->stat[MCS_RSS] += val * PAGE_SIZE;
2094 val = mem_cgroup_read_stat(&mem->stat, MEM_CGROUP_STAT_PGPGIN_COUNT);
2095 s->stat[MCS_PGPGIN] += val;
2096 val = mem_cgroup_read_stat(&mem->stat, MEM_CGROUP_STAT_PGPGOUT_COUNT);
2097 s->stat[MCS_PGPGOUT] += val;
2100 val = mem_cgroup_get_local_zonestat(mem, LRU_INACTIVE_ANON);
2101 s->stat[MCS_INACTIVE_ANON] += val * PAGE_SIZE;
2102 val = mem_cgroup_get_local_zonestat(mem, LRU_ACTIVE_ANON);
2103 s->stat[MCS_ACTIVE_ANON] += val * PAGE_SIZE;
2104 val = mem_cgroup_get_local_zonestat(mem, LRU_INACTIVE_FILE);
2105 s->stat[MCS_INACTIVE_FILE] += val * PAGE_SIZE;
2106 val = mem_cgroup_get_local_zonestat(mem, LRU_ACTIVE_FILE);
2107 s->stat[MCS_ACTIVE_FILE] += val * PAGE_SIZE;
2108 val = mem_cgroup_get_local_zonestat(mem, LRU_UNEVICTABLE);
2109 s->stat[MCS_UNEVICTABLE] += val * PAGE_SIZE;
2114 mem_cgroup_get_total_stat(struct mem_cgroup *mem, struct mcs_total_stat *s)
2116 mem_cgroup_walk_tree(mem, s, mem_cgroup_get_local_stat);
2119 static int mem_control_stat_show(struct cgroup *cont, struct cftype *cft,
2120 struct cgroup_map_cb *cb)
2122 struct mem_cgroup *mem_cont = mem_cgroup_from_cont(cont);
2123 struct mcs_total_stat mystat;
2126 memset(&mystat, 0, sizeof(mystat));
2127 mem_cgroup_get_local_stat(mem_cont, &mystat);
2129 for (i = 0; i < NR_MCS_STAT; i++)
2130 cb->fill(cb, memcg_stat_strings[i].local_name, mystat.stat[i]);
2132 /* Hierarchical information */
2134 unsigned long long limit, memsw_limit;
2135 memcg_get_hierarchical_limit(mem_cont, &limit, &memsw_limit);
2136 cb->fill(cb, "hierarchical_memory_limit", limit);
2137 if (do_swap_account)
2138 cb->fill(cb, "hierarchical_memsw_limit", memsw_limit);
2141 memset(&mystat, 0, sizeof(mystat));
2142 mem_cgroup_get_total_stat(mem_cont, &mystat);
2143 for (i = 0; i < NR_MCS_STAT; i++)
2144 cb->fill(cb, memcg_stat_strings[i].total_name, mystat.stat[i]);
2147 #ifdef CONFIG_DEBUG_VM
2148 cb->fill(cb, "inactive_ratio", calc_inactive_ratio(mem_cont, NULL));
2152 struct mem_cgroup_per_zone *mz;
2153 unsigned long recent_rotated[2] = {0, 0};
2154 unsigned long recent_scanned[2] = {0, 0};
2156 for_each_online_node(nid)
2157 for (zid = 0; zid < MAX_NR_ZONES; zid++) {
2158 mz = mem_cgroup_zoneinfo(mem_cont, nid, zid);
2160 recent_rotated[0] +=
2161 mz->reclaim_stat.recent_rotated[0];
2162 recent_rotated[1] +=
2163 mz->reclaim_stat.recent_rotated[1];
2164 recent_scanned[0] +=
2165 mz->reclaim_stat.recent_scanned[0];
2166 recent_scanned[1] +=
2167 mz->reclaim_stat.recent_scanned[1];
2169 cb->fill(cb, "recent_rotated_anon", recent_rotated[0]);
2170 cb->fill(cb, "recent_rotated_file", recent_rotated[1]);
2171 cb->fill(cb, "recent_scanned_anon", recent_scanned[0]);
2172 cb->fill(cb, "recent_scanned_file", recent_scanned[1]);
2179 static u64 mem_cgroup_swappiness_read(struct cgroup *cgrp, struct cftype *cft)
2181 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
2183 return get_swappiness(memcg);
2186 static int mem_cgroup_swappiness_write(struct cgroup *cgrp, struct cftype *cft,
2189 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
2190 struct mem_cgroup *parent;
2195 if (cgrp->parent == NULL)
2198 parent = mem_cgroup_from_cont(cgrp->parent);
2202 /* If under hierarchy, only empty-root can set this value */
2203 if ((parent->use_hierarchy) ||
2204 (memcg->use_hierarchy && !list_empty(&cgrp->children))) {
2209 spin_lock(&memcg->reclaim_param_lock);
2210 memcg->swappiness = val;
2211 spin_unlock(&memcg->reclaim_param_lock);
2219 static struct cftype mem_cgroup_files[] = {
2221 .name = "usage_in_bytes",
2222 .private = MEMFILE_PRIVATE(_MEM, RES_USAGE),
2223 .read_u64 = mem_cgroup_read,
2226 .name = "max_usage_in_bytes",
2227 .private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE),
2228 .trigger = mem_cgroup_reset,
2229 .read_u64 = mem_cgroup_read,
2232 .name = "limit_in_bytes",
2233 .private = MEMFILE_PRIVATE(_MEM, RES_LIMIT),
2234 .write_string = mem_cgroup_write,
2235 .read_u64 = mem_cgroup_read,
2239 .private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT),
2240 .trigger = mem_cgroup_reset,
2241 .read_u64 = mem_cgroup_read,
2245 .read_map = mem_control_stat_show,
2248 .name = "force_empty",
2249 .trigger = mem_cgroup_force_empty_write,
2252 .name = "use_hierarchy",
2253 .write_u64 = mem_cgroup_hierarchy_write,
2254 .read_u64 = mem_cgroup_hierarchy_read,
2257 .name = "swappiness",
2258 .read_u64 = mem_cgroup_swappiness_read,
2259 .write_u64 = mem_cgroup_swappiness_write,
2263 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
2264 static struct cftype memsw_cgroup_files[] = {
2266 .name = "memsw.usage_in_bytes",
2267 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE),
2268 .read_u64 = mem_cgroup_read,
2271 .name = "memsw.max_usage_in_bytes",
2272 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE),
2273 .trigger = mem_cgroup_reset,
2274 .read_u64 = mem_cgroup_read,
2277 .name = "memsw.limit_in_bytes",
2278 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT),
2279 .write_string = mem_cgroup_write,
2280 .read_u64 = mem_cgroup_read,
2283 .name = "memsw.failcnt",
2284 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT),
2285 .trigger = mem_cgroup_reset,
2286 .read_u64 = mem_cgroup_read,
2290 static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss)
2292 if (!do_swap_account)
2294 return cgroup_add_files(cont, ss, memsw_cgroup_files,
2295 ARRAY_SIZE(memsw_cgroup_files));
2298 static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss)
2304 static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
2306 struct mem_cgroup_per_node *pn;
2307 struct mem_cgroup_per_zone *mz;
2309 int zone, tmp = node;
2311 * This routine is called against possible nodes.
2312 * But it's BUG to call kmalloc() against offline node.
2314 * TODO: this routine can waste much memory for nodes which will
2315 * never be onlined. It's better to use memory hotplug callback
2318 if (!node_state(node, N_NORMAL_MEMORY))
2320 pn = kmalloc_node(sizeof(*pn), GFP_KERNEL, tmp);
2324 mem->info.nodeinfo[node] = pn;
2325 memset(pn, 0, sizeof(*pn));
2327 for (zone = 0; zone < MAX_NR_ZONES; zone++) {
2328 mz = &pn->zoneinfo[zone];
2330 INIT_LIST_HEAD(&mz->lists[l]);
2335 static void free_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
2337 kfree(mem->info.nodeinfo[node]);
2340 static int mem_cgroup_size(void)
2342 int cpustat_size = nr_cpu_ids * sizeof(struct mem_cgroup_stat_cpu);
2343 return sizeof(struct mem_cgroup) + cpustat_size;
2346 static struct mem_cgroup *mem_cgroup_alloc(void)
2348 struct mem_cgroup *mem;
2349 int size = mem_cgroup_size();
2351 if (size < PAGE_SIZE)
2352 mem = kmalloc(size, GFP_KERNEL);
2354 mem = vmalloc(size);
2357 memset(mem, 0, size);
2362 * At destroying mem_cgroup, references from swap_cgroup can remain.
2363 * (scanning all at force_empty is too costly...)
2365 * Instead of clearing all references at force_empty, we remember
2366 * the number of reference from swap_cgroup and free mem_cgroup when
2367 * it goes down to 0.
2369 * Removal of cgroup itself succeeds regardless of refs from swap.
2372 static void __mem_cgroup_free(struct mem_cgroup *mem)
2376 free_css_id(&mem_cgroup_subsys, &mem->css);
2378 for_each_node_state(node, N_POSSIBLE)
2379 free_mem_cgroup_per_zone_info(mem, node);
2381 if (mem_cgroup_size() < PAGE_SIZE)
2387 static void mem_cgroup_get(struct mem_cgroup *mem)
2389 atomic_inc(&mem->refcnt);
2392 static void mem_cgroup_put(struct mem_cgroup *mem)
2394 if (atomic_dec_and_test(&mem->refcnt)) {
2395 struct mem_cgroup *parent = parent_mem_cgroup(mem);
2396 __mem_cgroup_free(mem);
2398 mem_cgroup_put(parent);
2403 * Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled.
2405 static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem)
2407 if (!mem->res.parent)
2409 return mem_cgroup_from_res_counter(mem->res.parent, res);
2412 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
2413 static void __init enable_swap_cgroup(void)
2415 if (!mem_cgroup_disabled() && really_do_swap_account)
2416 do_swap_account = 1;
2419 static void __init enable_swap_cgroup(void)
2424 static struct cgroup_subsys_state * __ref
2425 mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
2427 struct mem_cgroup *mem, *parent;
2428 long error = -ENOMEM;
2431 mem = mem_cgroup_alloc();
2433 return ERR_PTR(error);
2435 for_each_node_state(node, N_POSSIBLE)
2436 if (alloc_mem_cgroup_per_zone_info(mem, node))
2439 if (cont->parent == NULL) {
2440 enable_swap_cgroup();
2443 parent = mem_cgroup_from_cont(cont->parent);
2444 mem->use_hierarchy = parent->use_hierarchy;
2447 if (parent && parent->use_hierarchy) {
2448 res_counter_init(&mem->res, &parent->res);
2449 res_counter_init(&mem->memsw, &parent->memsw);
2451 * We increment refcnt of the parent to ensure that we can
2452 * safely access it on res_counter_charge/uncharge.
2453 * This refcnt will be decremented when freeing this
2454 * mem_cgroup(see mem_cgroup_put).
2456 mem_cgroup_get(parent);
2458 res_counter_init(&mem->res, NULL);
2459 res_counter_init(&mem->memsw, NULL);
2461 mem->last_scanned_child = 0;
2462 spin_lock_init(&mem->reclaim_param_lock);
2465 mem->swappiness = get_swappiness(parent);
2466 atomic_set(&mem->refcnt, 1);
2469 __mem_cgroup_free(mem);
2470 return ERR_PTR(error);
2473 static int mem_cgroup_pre_destroy(struct cgroup_subsys *ss,
2474 struct cgroup *cont)
2476 struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
2478 return mem_cgroup_force_empty(mem, false);
2481 static void mem_cgroup_destroy(struct cgroup_subsys *ss,
2482 struct cgroup *cont)
2484 struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
2486 mem_cgroup_put(mem);
2489 static int mem_cgroup_populate(struct cgroup_subsys *ss,
2490 struct cgroup *cont)
2494 ret = cgroup_add_files(cont, ss, mem_cgroup_files,
2495 ARRAY_SIZE(mem_cgroup_files));
2498 ret = register_memsw_files(cont, ss);
2502 static void mem_cgroup_move_task(struct cgroup_subsys *ss,
2503 struct cgroup *cont,
2504 struct cgroup *old_cont,
2505 struct task_struct *p)
2507 mutex_lock(&memcg_tasklist);
2509 * FIXME: It's better to move charges of this process from old
2510 * memcg to new memcg. But it's just on TODO-List now.
2512 mutex_unlock(&memcg_tasklist);
2515 struct cgroup_subsys mem_cgroup_subsys = {
2517 .subsys_id = mem_cgroup_subsys_id,
2518 .create = mem_cgroup_create,
2519 .pre_destroy = mem_cgroup_pre_destroy,
2520 .destroy = mem_cgroup_destroy,
2521 .populate = mem_cgroup_populate,
2522 .attach = mem_cgroup_move_task,
2527 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
2529 static int __init disable_swap_account(char *s)
2531 really_do_swap_account = 0;
2534 __setup("noswapaccount", disable_swap_account);