CIFS: Fix endian conversion of vcnum field
[linux-2.6/mini2440.git] / mm / memcontrol.c
blob8e4be9cb2a6a7642601516e3587d151dcea586f4
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>
23 #include <linux/mm.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/mutex.h>
31 #include <linux/slab.h>
32 #include <linux/swap.h>
33 #include <linux/spinlock.h>
34 #include <linux/fs.h>
35 #include <linux/seq_file.h>
36 #include <linux/vmalloc.h>
37 #include <linux/mm_inline.h>
38 #include <linux/page_cgroup.h>
39 #include "internal.h"
41 #include <asm/uaccess.h>
43 struct cgroup_subsys mem_cgroup_subsys __read_mostly;
44 #define MEM_CGROUP_RECLAIM_RETRIES 5
46 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
47 /* Turned on only when memory cgroup is enabled && really_do_swap_account = 0 */
48 int do_swap_account __read_mostly;
49 static int really_do_swap_account __initdata = 1; /* for remember boot option*/
50 #else
51 #define do_swap_account (0)
52 #endif
54 static DEFINE_MUTEX(memcg_tasklist); /* can be hold under cgroup_mutex */
57 * Statistics for memory cgroup.
59 enum mem_cgroup_stat_index {
61 * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss.
63 MEM_CGROUP_STAT_CACHE, /* # of pages charged as cache */
64 MEM_CGROUP_STAT_RSS, /* # of pages charged as rss */
65 MEM_CGROUP_STAT_PGPGIN_COUNT, /* # of pages paged in */
66 MEM_CGROUP_STAT_PGPGOUT_COUNT, /* # of pages paged out */
68 MEM_CGROUP_STAT_NSTATS,
71 struct mem_cgroup_stat_cpu {
72 s64 count[MEM_CGROUP_STAT_NSTATS];
73 } ____cacheline_aligned_in_smp;
75 struct mem_cgroup_stat {
76 struct mem_cgroup_stat_cpu cpustat[0];
80 * For accounting under irq disable, no need for increment preempt count.
82 static inline void __mem_cgroup_stat_add_safe(struct mem_cgroup_stat_cpu *stat,
83 enum mem_cgroup_stat_index idx, int val)
85 stat->count[idx] += val;
88 static s64 mem_cgroup_read_stat(struct mem_cgroup_stat *stat,
89 enum mem_cgroup_stat_index idx)
91 int cpu;
92 s64 ret = 0;
93 for_each_possible_cpu(cpu)
94 ret += stat->cpustat[cpu].count[idx];
95 return ret;
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;
110 /* Macro for accessing counter */
111 #define MEM_CGROUP_ZSTAT(mz, idx) ((mz)->count[(idx)])
113 struct mem_cgroup_per_node {
114 struct mem_cgroup_per_zone zoneinfo[MAX_NR_ZONES];
117 struct mem_cgroup_lru_info {
118 struct mem_cgroup_per_node *nodeinfo[MAX_NUMNODES];
122 * The memory controller data structure. The memory controller controls both
123 * page cache and RSS per cgroup. We would eventually like to provide
124 * statistics based on the statistics developed by Rik Van Riel for clock-pro,
125 * to help the administrator determine what knobs to tune.
127 * TODO: Add a water mark for the memory controller. Reclaim will begin when
128 * we hit the water mark. May be even add a low water mark, such that
129 * no reclaim occurs from a cgroup at it's low water mark, this is
130 * a feature that will be implemented much later in the future.
132 struct mem_cgroup {
133 struct cgroup_subsys_state css;
135 * the counter to account for memory usage
137 struct res_counter res;
139 * the counter to account for mem+swap usage.
141 struct res_counter memsw;
143 * Per cgroup active and inactive list, similar to the
144 * per zone LRU lists.
146 struct mem_cgroup_lru_info info;
149 protect against reclaim related member.
151 spinlock_t reclaim_param_lock;
153 int prev_priority; /* for recording reclaim priority */
156 * While reclaiming in a hiearchy, we cache the last child we
157 * reclaimed from. Protected by hierarchy_mutex
159 struct mem_cgroup *last_scanned_child;
161 * Should the accounting and control be hierarchical, per subtree?
163 bool use_hierarchy;
164 unsigned long last_oom_jiffies;
165 atomic_t refcnt;
167 unsigned int swappiness;
170 * statistics. This must be placed at the end of memcg.
172 struct mem_cgroup_stat stat;
175 enum charge_type {
176 MEM_CGROUP_CHARGE_TYPE_CACHE = 0,
177 MEM_CGROUP_CHARGE_TYPE_MAPPED,
178 MEM_CGROUP_CHARGE_TYPE_SHMEM, /* used by page migration of shmem */
179 MEM_CGROUP_CHARGE_TYPE_FORCE, /* used by force_empty */
180 MEM_CGROUP_CHARGE_TYPE_SWAPOUT, /* for accounting swapcache */
181 NR_CHARGE_TYPE,
184 /* only for here (for easy reading.) */
185 #define PCGF_CACHE (1UL << PCG_CACHE)
186 #define PCGF_USED (1UL << PCG_USED)
187 #define PCGF_LOCK (1UL << PCG_LOCK)
188 static const unsigned long
189 pcg_default_flags[NR_CHARGE_TYPE] = {
190 PCGF_CACHE | PCGF_USED | PCGF_LOCK, /* File Cache */
191 PCGF_USED | PCGF_LOCK, /* Anon */
192 PCGF_CACHE | PCGF_USED | PCGF_LOCK, /* Shmem */
193 0, /* FORCE */
196 /* for encoding cft->private value on file */
197 #define _MEM (0)
198 #define _MEMSWAP (1)
199 #define MEMFILE_PRIVATE(x, val) (((x) << 16) | (val))
200 #define MEMFILE_TYPE(val) (((val) >> 16) & 0xffff)
201 #define MEMFILE_ATTR(val) ((val) & 0xffff)
203 static void mem_cgroup_get(struct mem_cgroup *mem);
204 static void mem_cgroup_put(struct mem_cgroup *mem);
205 static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem);
207 static void mem_cgroup_charge_statistics(struct mem_cgroup *mem,
208 struct page_cgroup *pc,
209 bool charge)
211 int val = (charge)? 1 : -1;
212 struct mem_cgroup_stat *stat = &mem->stat;
213 struct mem_cgroup_stat_cpu *cpustat;
214 int cpu = get_cpu();
216 cpustat = &stat->cpustat[cpu];
217 if (PageCgroupCache(pc))
218 __mem_cgroup_stat_add_safe(cpustat, MEM_CGROUP_STAT_CACHE, val);
219 else
220 __mem_cgroup_stat_add_safe(cpustat, MEM_CGROUP_STAT_RSS, val);
222 if (charge)
223 __mem_cgroup_stat_add_safe(cpustat,
224 MEM_CGROUP_STAT_PGPGIN_COUNT, 1);
225 else
226 __mem_cgroup_stat_add_safe(cpustat,
227 MEM_CGROUP_STAT_PGPGOUT_COUNT, 1);
228 put_cpu();
231 static struct mem_cgroup_per_zone *
232 mem_cgroup_zoneinfo(struct mem_cgroup *mem, int nid, int zid)
234 return &mem->info.nodeinfo[nid]->zoneinfo[zid];
237 static struct mem_cgroup_per_zone *
238 page_cgroup_zoneinfo(struct page_cgroup *pc)
240 struct mem_cgroup *mem = pc->mem_cgroup;
241 int nid = page_cgroup_nid(pc);
242 int zid = page_cgroup_zid(pc);
244 if (!mem)
245 return NULL;
247 return mem_cgroup_zoneinfo(mem, nid, zid);
250 static unsigned long mem_cgroup_get_all_zonestat(struct mem_cgroup *mem,
251 enum lru_list idx)
253 int nid, zid;
254 struct mem_cgroup_per_zone *mz;
255 u64 total = 0;
257 for_each_online_node(nid)
258 for (zid = 0; zid < MAX_NR_ZONES; zid++) {
259 mz = mem_cgroup_zoneinfo(mem, nid, zid);
260 total += MEM_CGROUP_ZSTAT(mz, idx);
262 return total;
265 static struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont)
267 return container_of(cgroup_subsys_state(cont,
268 mem_cgroup_subsys_id), struct mem_cgroup,
269 css);
272 struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
275 * mm_update_next_owner() may clear mm->owner to NULL
276 * if it races with swapoff, page migration, etc.
277 * So this can be called with p == NULL.
279 if (unlikely(!p))
280 return NULL;
282 return container_of(task_subsys_state(p, mem_cgroup_subsys_id),
283 struct mem_cgroup, css);
286 static struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm)
288 struct mem_cgroup *mem = NULL;
290 * Because we have no locks, mm->owner's may be being moved to other
291 * cgroup. We use css_tryget() here even if this looks
292 * pessimistic (rather than adding locks here).
294 rcu_read_lock();
295 do {
296 mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
297 if (unlikely(!mem))
298 break;
299 } while (!css_tryget(&mem->css));
300 rcu_read_unlock();
301 return mem;
304 static bool mem_cgroup_is_obsolete(struct mem_cgroup *mem)
306 if (!mem)
307 return true;
308 return css_is_removed(&mem->css);
312 * Following LRU functions are allowed to be used without PCG_LOCK.
313 * Operations are called by routine of global LRU independently from memcg.
314 * What we have to take care of here is validness of pc->mem_cgroup.
316 * Changes to pc->mem_cgroup happens when
317 * 1. charge
318 * 2. moving account
319 * In typical case, "charge" is done before add-to-lru. Exception is SwapCache.
320 * It is added to LRU before charge.
321 * If PCG_USED bit is not set, page_cgroup is not added to this private LRU.
322 * When moving account, the page is not on LRU. It's isolated.
325 void mem_cgroup_del_lru_list(struct page *page, enum lru_list lru)
327 struct page_cgroup *pc;
328 struct mem_cgroup *mem;
329 struct mem_cgroup_per_zone *mz;
331 if (mem_cgroup_disabled())
332 return;
333 pc = lookup_page_cgroup(page);
334 /* can happen while we handle swapcache. */
335 if (list_empty(&pc->lru) || !pc->mem_cgroup)
336 return;
338 * We don't check PCG_USED bit. It's cleared when the "page" is finally
339 * removed from global LRU.
341 mz = page_cgroup_zoneinfo(pc);
342 mem = pc->mem_cgroup;
343 MEM_CGROUP_ZSTAT(mz, lru) -= 1;
344 list_del_init(&pc->lru);
345 return;
348 void mem_cgroup_del_lru(struct page *page)
350 mem_cgroup_del_lru_list(page, page_lru(page));
353 void mem_cgroup_rotate_lru_list(struct page *page, enum lru_list lru)
355 struct mem_cgroup_per_zone *mz;
356 struct page_cgroup *pc;
358 if (mem_cgroup_disabled())
359 return;
361 pc = lookup_page_cgroup(page);
363 * Used bit is set without atomic ops but after smp_wmb().
364 * For making pc->mem_cgroup visible, insert smp_rmb() here.
366 smp_rmb();
367 /* unused page is not rotated. */
368 if (!PageCgroupUsed(pc))
369 return;
370 mz = page_cgroup_zoneinfo(pc);
371 list_move(&pc->lru, &mz->lists[lru]);
374 void mem_cgroup_add_lru_list(struct page *page, enum lru_list lru)
376 struct page_cgroup *pc;
377 struct mem_cgroup_per_zone *mz;
379 if (mem_cgroup_disabled())
380 return;
381 pc = lookup_page_cgroup(page);
383 * Used bit is set without atomic ops but after smp_wmb().
384 * For making pc->mem_cgroup visible, insert smp_rmb() here.
386 smp_rmb();
387 if (!PageCgroupUsed(pc))
388 return;
390 mz = page_cgroup_zoneinfo(pc);
391 MEM_CGROUP_ZSTAT(mz, lru) += 1;
392 list_add(&pc->lru, &mz->lists[lru]);
396 * At handling SwapCache, pc->mem_cgroup may be changed while it's linked to
397 * lru because the page may.be reused after it's fully uncharged (because of
398 * SwapCache behavior).To handle that, unlink page_cgroup from LRU when charge
399 * it again. This function is only used to charge SwapCache. It's done under
400 * lock_page and expected that zone->lru_lock is never held.
402 static void mem_cgroup_lru_del_before_commit_swapcache(struct page *page)
404 unsigned long flags;
405 struct zone *zone = page_zone(page);
406 struct page_cgroup *pc = lookup_page_cgroup(page);
408 spin_lock_irqsave(&zone->lru_lock, flags);
410 * Forget old LRU when this page_cgroup is *not* used. This Used bit
411 * is guarded by lock_page() because the page is SwapCache.
413 if (!PageCgroupUsed(pc))
414 mem_cgroup_del_lru_list(page, page_lru(page));
415 spin_unlock_irqrestore(&zone->lru_lock, flags);
418 static void mem_cgroup_lru_add_after_commit_swapcache(struct page *page)
420 unsigned long flags;
421 struct zone *zone = page_zone(page);
422 struct page_cgroup *pc = lookup_page_cgroup(page);
424 spin_lock_irqsave(&zone->lru_lock, flags);
425 /* link when the page is linked to LRU but page_cgroup isn't */
426 if (PageLRU(page) && list_empty(&pc->lru))
427 mem_cgroup_add_lru_list(page, page_lru(page));
428 spin_unlock_irqrestore(&zone->lru_lock, flags);
432 void mem_cgroup_move_lists(struct page *page,
433 enum lru_list from, enum lru_list to)
435 if (mem_cgroup_disabled())
436 return;
437 mem_cgroup_del_lru_list(page, from);
438 mem_cgroup_add_lru_list(page, to);
441 int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem)
443 int ret;
445 task_lock(task);
446 ret = task->mm && mm_match_cgroup(task->mm, mem);
447 task_unlock(task);
448 return ret;
452 * Calculate mapped_ratio under memory controller. This will be used in
453 * vmscan.c for deteremining we have to reclaim mapped pages.
455 int mem_cgroup_calc_mapped_ratio(struct mem_cgroup *mem)
457 long total, rss;
460 * usage is recorded in bytes. But, here, we assume the number of
461 * physical pages can be represented by "long" on any arch.
463 total = (long) (mem->res.usage >> PAGE_SHIFT) + 1L;
464 rss = (long)mem_cgroup_read_stat(&mem->stat, MEM_CGROUP_STAT_RSS);
465 return (int)((rss * 100L) / total);
469 * prev_priority control...this will be used in memory reclaim path.
471 int mem_cgroup_get_reclaim_priority(struct mem_cgroup *mem)
473 int prev_priority;
475 spin_lock(&mem->reclaim_param_lock);
476 prev_priority = mem->prev_priority;
477 spin_unlock(&mem->reclaim_param_lock);
479 return prev_priority;
482 void mem_cgroup_note_reclaim_priority(struct mem_cgroup *mem, int priority)
484 spin_lock(&mem->reclaim_param_lock);
485 if (priority < mem->prev_priority)
486 mem->prev_priority = priority;
487 spin_unlock(&mem->reclaim_param_lock);
490 void mem_cgroup_record_reclaim_priority(struct mem_cgroup *mem, int priority)
492 spin_lock(&mem->reclaim_param_lock);
493 mem->prev_priority = priority;
494 spin_unlock(&mem->reclaim_param_lock);
497 static int calc_inactive_ratio(struct mem_cgroup *memcg, unsigned long *present_pages)
499 unsigned long active;
500 unsigned long inactive;
501 unsigned long gb;
502 unsigned long inactive_ratio;
504 inactive = mem_cgroup_get_all_zonestat(memcg, LRU_INACTIVE_ANON);
505 active = mem_cgroup_get_all_zonestat(memcg, LRU_ACTIVE_ANON);
507 gb = (inactive + active) >> (30 - PAGE_SHIFT);
508 if (gb)
509 inactive_ratio = int_sqrt(10 * gb);
510 else
511 inactive_ratio = 1;
513 if (present_pages) {
514 present_pages[0] = inactive;
515 present_pages[1] = active;
518 return inactive_ratio;
521 int mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg)
523 unsigned long active;
524 unsigned long inactive;
525 unsigned long present_pages[2];
526 unsigned long inactive_ratio;
528 inactive_ratio = calc_inactive_ratio(memcg, present_pages);
530 inactive = present_pages[0];
531 active = present_pages[1];
533 if (inactive * inactive_ratio < active)
534 return 1;
536 return 0;
539 unsigned long mem_cgroup_zone_nr_pages(struct mem_cgroup *memcg,
540 struct zone *zone,
541 enum lru_list lru)
543 int nid = zone->zone_pgdat->node_id;
544 int zid = zone_idx(zone);
545 struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid);
547 return MEM_CGROUP_ZSTAT(mz, lru);
550 struct zone_reclaim_stat *mem_cgroup_get_reclaim_stat(struct mem_cgroup *memcg,
551 struct zone *zone)
553 int nid = zone->zone_pgdat->node_id;
554 int zid = zone_idx(zone);
555 struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid);
557 return &mz->reclaim_stat;
560 struct zone_reclaim_stat *
561 mem_cgroup_get_reclaim_stat_from_page(struct page *page)
563 struct page_cgroup *pc;
564 struct mem_cgroup_per_zone *mz;
566 if (mem_cgroup_disabled())
567 return NULL;
569 pc = lookup_page_cgroup(page);
571 * Used bit is set without atomic ops but after smp_wmb().
572 * For making pc->mem_cgroup visible, insert smp_rmb() here.
574 smp_rmb();
575 if (!PageCgroupUsed(pc))
576 return NULL;
578 mz = page_cgroup_zoneinfo(pc);
579 if (!mz)
580 return NULL;
582 return &mz->reclaim_stat;
585 unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
586 struct list_head *dst,
587 unsigned long *scanned, int order,
588 int mode, struct zone *z,
589 struct mem_cgroup *mem_cont,
590 int active, int file)
592 unsigned long nr_taken = 0;
593 struct page *page;
594 unsigned long scan;
595 LIST_HEAD(pc_list);
596 struct list_head *src;
597 struct page_cgroup *pc, *tmp;
598 int nid = z->zone_pgdat->node_id;
599 int zid = zone_idx(z);
600 struct mem_cgroup_per_zone *mz;
601 int lru = LRU_FILE * !!file + !!active;
603 BUG_ON(!mem_cont);
604 mz = mem_cgroup_zoneinfo(mem_cont, nid, zid);
605 src = &mz->lists[lru];
607 scan = 0;
608 list_for_each_entry_safe_reverse(pc, tmp, src, lru) {
609 if (scan >= nr_to_scan)
610 break;
612 page = pc->page;
613 if (unlikely(!PageCgroupUsed(pc)))
614 continue;
615 if (unlikely(!PageLRU(page)))
616 continue;
618 scan++;
619 if (__isolate_lru_page(page, mode, file) == 0) {
620 list_move(&page->lru, dst);
621 nr_taken++;
625 *scanned = scan;
626 return nr_taken;
629 #define mem_cgroup_from_res_counter(counter, member) \
630 container_of(counter, struct mem_cgroup, member)
633 * This routine finds the DFS walk successor. This routine should be
634 * called with hierarchy_mutex held
636 static struct mem_cgroup *
637 __mem_cgroup_get_next_node(struct mem_cgroup *curr, struct mem_cgroup *root_mem)
639 struct cgroup *cgroup, *curr_cgroup, *root_cgroup;
641 curr_cgroup = curr->css.cgroup;
642 root_cgroup = root_mem->css.cgroup;
644 if (!list_empty(&curr_cgroup->children)) {
646 * Walk down to children
648 cgroup = list_entry(curr_cgroup->children.next,
649 struct cgroup, sibling);
650 curr = mem_cgroup_from_cont(cgroup);
651 goto done;
654 visit_parent:
655 if (curr_cgroup == root_cgroup) {
656 /* caller handles NULL case */
657 curr = NULL;
658 goto done;
662 * Goto next sibling
664 if (curr_cgroup->sibling.next != &curr_cgroup->parent->children) {
665 cgroup = list_entry(curr_cgroup->sibling.next, struct cgroup,
666 sibling);
667 curr = mem_cgroup_from_cont(cgroup);
668 goto done;
672 * Go up to next parent and next parent's sibling if need be
674 curr_cgroup = curr_cgroup->parent;
675 goto visit_parent;
677 done:
678 return curr;
682 * Visit the first child (need not be the first child as per the ordering
683 * of the cgroup list, since we track last_scanned_child) of @mem and use
684 * that to reclaim free pages from.
686 static struct mem_cgroup *
687 mem_cgroup_get_next_node(struct mem_cgroup *root_mem)
689 struct cgroup *cgroup;
690 struct mem_cgroup *orig, *next;
691 bool obsolete;
694 * Scan all children under the mem_cgroup mem
696 mutex_lock(&mem_cgroup_subsys.hierarchy_mutex);
698 orig = root_mem->last_scanned_child;
699 obsolete = mem_cgroup_is_obsolete(orig);
701 if (list_empty(&root_mem->css.cgroup->children)) {
703 * root_mem might have children before and last_scanned_child
704 * may point to one of them. We put it later.
706 if (orig)
707 VM_BUG_ON(!obsolete);
708 next = NULL;
709 goto done;
712 if (!orig || obsolete) {
713 cgroup = list_first_entry(&root_mem->css.cgroup->children,
714 struct cgroup, sibling);
715 next = mem_cgroup_from_cont(cgroup);
716 } else
717 next = __mem_cgroup_get_next_node(orig, root_mem);
719 done:
720 if (next)
721 mem_cgroup_get(next);
722 root_mem->last_scanned_child = next;
723 if (orig)
724 mem_cgroup_put(orig);
725 mutex_unlock(&mem_cgroup_subsys.hierarchy_mutex);
726 return (next) ? next : root_mem;
729 static bool mem_cgroup_check_under_limit(struct mem_cgroup *mem)
731 if (do_swap_account) {
732 if (res_counter_check_under_limit(&mem->res) &&
733 res_counter_check_under_limit(&mem->memsw))
734 return true;
735 } else
736 if (res_counter_check_under_limit(&mem->res))
737 return true;
738 return false;
741 static unsigned int get_swappiness(struct mem_cgroup *memcg)
743 struct cgroup *cgrp = memcg->css.cgroup;
744 unsigned int swappiness;
746 /* root ? */
747 if (cgrp->parent == NULL)
748 return vm_swappiness;
750 spin_lock(&memcg->reclaim_param_lock);
751 swappiness = memcg->swappiness;
752 spin_unlock(&memcg->reclaim_param_lock);
754 return swappiness;
758 * Dance down the hierarchy if needed to reclaim memory. We remember the
759 * last child we reclaimed from, so that we don't end up penalizing
760 * one child extensively based on its position in the children list.
762 * root_mem is the original ancestor that we've been reclaim from.
764 static int mem_cgroup_hierarchical_reclaim(struct mem_cgroup *root_mem,
765 gfp_t gfp_mask, bool noswap)
767 struct mem_cgroup *next_mem;
768 int ret = 0;
771 * Reclaim unconditionally and don't check for return value.
772 * We need to reclaim in the current group and down the tree.
773 * One might think about checking for children before reclaiming,
774 * but there might be left over accounting, even after children
775 * have left.
777 ret += try_to_free_mem_cgroup_pages(root_mem, gfp_mask, noswap,
778 get_swappiness(root_mem));
779 if (mem_cgroup_check_under_limit(root_mem))
780 return 1; /* indicate reclaim has succeeded */
781 if (!root_mem->use_hierarchy)
782 return ret;
784 next_mem = mem_cgroup_get_next_node(root_mem);
786 while (next_mem != root_mem) {
787 if (mem_cgroup_is_obsolete(next_mem)) {
788 next_mem = mem_cgroup_get_next_node(root_mem);
789 continue;
791 ret += try_to_free_mem_cgroup_pages(next_mem, gfp_mask, noswap,
792 get_swappiness(next_mem));
793 if (mem_cgroup_check_under_limit(root_mem))
794 return 1; /* indicate reclaim has succeeded */
795 next_mem = mem_cgroup_get_next_node(root_mem);
797 return ret;
800 bool mem_cgroup_oom_called(struct task_struct *task)
802 bool ret = false;
803 struct mem_cgroup *mem;
804 struct mm_struct *mm;
806 rcu_read_lock();
807 mm = task->mm;
808 if (!mm)
809 mm = &init_mm;
810 mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
811 if (mem && time_before(jiffies, mem->last_oom_jiffies + HZ/10))
812 ret = true;
813 rcu_read_unlock();
814 return ret;
817 * Unlike exported interface, "oom" parameter is added. if oom==true,
818 * oom-killer can be invoked.
820 static int __mem_cgroup_try_charge(struct mm_struct *mm,
821 gfp_t gfp_mask, struct mem_cgroup **memcg,
822 bool oom)
824 struct mem_cgroup *mem, *mem_over_limit;
825 int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
826 struct res_counter *fail_res;
828 if (unlikely(test_thread_flag(TIF_MEMDIE))) {
829 /* Don't account this! */
830 *memcg = NULL;
831 return 0;
835 * We always charge the cgroup the mm_struct belongs to.
836 * The mm_struct's mem_cgroup changes on task migration if the
837 * thread group leader migrates. It's possible that mm is not
838 * set, if so charge the init_mm (happens for pagecache usage).
840 mem = *memcg;
841 if (likely(!mem)) {
842 mem = try_get_mem_cgroup_from_mm(mm);
843 *memcg = mem;
844 } else {
845 css_get(&mem->css);
847 if (unlikely(!mem))
848 return 0;
850 VM_BUG_ON(mem_cgroup_is_obsolete(mem));
852 while (1) {
853 int ret;
854 bool noswap = false;
856 ret = res_counter_charge(&mem->res, PAGE_SIZE, &fail_res);
857 if (likely(!ret)) {
858 if (!do_swap_account)
859 break;
860 ret = res_counter_charge(&mem->memsw, PAGE_SIZE,
861 &fail_res);
862 if (likely(!ret))
863 break;
864 /* mem+swap counter fails */
865 res_counter_uncharge(&mem->res, PAGE_SIZE);
866 noswap = true;
867 mem_over_limit = mem_cgroup_from_res_counter(fail_res,
868 memsw);
869 } else
870 /* mem counter fails */
871 mem_over_limit = mem_cgroup_from_res_counter(fail_res,
872 res);
874 if (!(gfp_mask & __GFP_WAIT))
875 goto nomem;
877 ret = mem_cgroup_hierarchical_reclaim(mem_over_limit, gfp_mask,
878 noswap);
879 if (ret)
880 continue;
883 * try_to_free_mem_cgroup_pages() might not give us a full
884 * picture of reclaim. Some pages are reclaimed and might be
885 * moved to swap cache or just unmapped from the cgroup.
886 * Check the limit again to see if the reclaim reduced the
887 * current usage of the cgroup before giving up
890 if (mem_cgroup_check_under_limit(mem_over_limit))
891 continue;
893 if (!nr_retries--) {
894 if (oom) {
895 mutex_lock(&memcg_tasklist);
896 mem_cgroup_out_of_memory(mem_over_limit, gfp_mask);
897 mutex_unlock(&memcg_tasklist);
898 mem_over_limit->last_oom_jiffies = jiffies;
900 goto nomem;
903 return 0;
904 nomem:
905 css_put(&mem->css);
906 return -ENOMEM;
909 static struct mem_cgroup *try_get_mem_cgroup_from_swapcache(struct page *page)
911 struct mem_cgroup *mem;
912 swp_entry_t ent;
914 if (!PageSwapCache(page))
915 return NULL;
917 ent.val = page_private(page);
918 mem = lookup_swap_cgroup(ent);
919 if (!mem)
920 return NULL;
921 if (!css_tryget(&mem->css))
922 return NULL;
923 return mem;
927 * commit a charge got by __mem_cgroup_try_charge() and makes page_cgroup to be
928 * USED state. If already USED, uncharge and return.
931 static void __mem_cgroup_commit_charge(struct mem_cgroup *mem,
932 struct page_cgroup *pc,
933 enum charge_type ctype)
935 /* try_charge() can return NULL to *memcg, taking care of it. */
936 if (!mem)
937 return;
939 lock_page_cgroup(pc);
940 if (unlikely(PageCgroupUsed(pc))) {
941 unlock_page_cgroup(pc);
942 res_counter_uncharge(&mem->res, PAGE_SIZE);
943 if (do_swap_account)
944 res_counter_uncharge(&mem->memsw, PAGE_SIZE);
945 css_put(&mem->css);
946 return;
948 pc->mem_cgroup = mem;
949 smp_wmb();
950 pc->flags = pcg_default_flags[ctype];
952 mem_cgroup_charge_statistics(mem, pc, true);
954 unlock_page_cgroup(pc);
958 * mem_cgroup_move_account - move account of the page
959 * @pc: page_cgroup of the page.
960 * @from: mem_cgroup which the page is moved from.
961 * @to: mem_cgroup which the page is moved to. @from != @to.
963 * The caller must confirm following.
964 * - page is not on LRU (isolate_page() is useful.)
966 * returns 0 at success,
967 * returns -EBUSY when lock is busy or "pc" is unstable.
969 * This function does "uncharge" from old cgroup but doesn't do "charge" to
970 * new cgroup. It should be done by a caller.
973 static int mem_cgroup_move_account(struct page_cgroup *pc,
974 struct mem_cgroup *from, struct mem_cgroup *to)
976 struct mem_cgroup_per_zone *from_mz, *to_mz;
977 int nid, zid;
978 int ret = -EBUSY;
980 VM_BUG_ON(from == to);
981 VM_BUG_ON(PageLRU(pc->page));
983 nid = page_cgroup_nid(pc);
984 zid = page_cgroup_zid(pc);
985 from_mz = mem_cgroup_zoneinfo(from, nid, zid);
986 to_mz = mem_cgroup_zoneinfo(to, nid, zid);
988 if (!trylock_page_cgroup(pc))
989 return ret;
991 if (!PageCgroupUsed(pc))
992 goto out;
994 if (pc->mem_cgroup != from)
995 goto out;
997 res_counter_uncharge(&from->res, PAGE_SIZE);
998 mem_cgroup_charge_statistics(from, pc, false);
999 if (do_swap_account)
1000 res_counter_uncharge(&from->memsw, PAGE_SIZE);
1001 css_put(&from->css);
1003 css_get(&to->css);
1004 pc->mem_cgroup = to;
1005 mem_cgroup_charge_statistics(to, pc, true);
1006 ret = 0;
1007 out:
1008 unlock_page_cgroup(pc);
1009 return ret;
1013 * move charges to its parent.
1016 static int mem_cgroup_move_parent(struct page_cgroup *pc,
1017 struct mem_cgroup *child,
1018 gfp_t gfp_mask)
1020 struct page *page = pc->page;
1021 struct cgroup *cg = child->css.cgroup;
1022 struct cgroup *pcg = cg->parent;
1023 struct mem_cgroup *parent;
1024 int ret;
1026 /* Is ROOT ? */
1027 if (!pcg)
1028 return -EINVAL;
1031 parent = mem_cgroup_from_cont(pcg);
1034 ret = __mem_cgroup_try_charge(NULL, gfp_mask, &parent, false);
1035 if (ret || !parent)
1036 return ret;
1038 if (!get_page_unless_zero(page)) {
1039 ret = -EBUSY;
1040 goto uncharge;
1043 ret = isolate_lru_page(page);
1045 if (ret)
1046 goto cancel;
1048 ret = mem_cgroup_move_account(pc, child, parent);
1050 putback_lru_page(page);
1051 if (!ret) {
1052 put_page(page);
1053 /* drop extra refcnt by try_charge() */
1054 css_put(&parent->css);
1055 return 0;
1058 cancel:
1059 put_page(page);
1060 uncharge:
1061 /* drop extra refcnt by try_charge() */
1062 css_put(&parent->css);
1063 /* uncharge if move fails */
1064 res_counter_uncharge(&parent->res, PAGE_SIZE);
1065 if (do_swap_account)
1066 res_counter_uncharge(&parent->memsw, PAGE_SIZE);
1067 return ret;
1071 * Charge the memory controller for page usage.
1072 * Return
1073 * 0 if the charge was successful
1074 * < 0 if the cgroup is over its limit
1076 static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm,
1077 gfp_t gfp_mask, enum charge_type ctype,
1078 struct mem_cgroup *memcg)
1080 struct mem_cgroup *mem;
1081 struct page_cgroup *pc;
1082 int ret;
1084 pc = lookup_page_cgroup(page);
1085 /* can happen at boot */
1086 if (unlikely(!pc))
1087 return 0;
1088 prefetchw(pc);
1090 mem = memcg;
1091 ret = __mem_cgroup_try_charge(mm, gfp_mask, &mem, true);
1092 if (ret || !mem)
1093 return ret;
1095 __mem_cgroup_commit_charge(mem, pc, ctype);
1096 return 0;
1099 int mem_cgroup_newpage_charge(struct page *page,
1100 struct mm_struct *mm, gfp_t gfp_mask)
1102 if (mem_cgroup_disabled())
1103 return 0;
1104 if (PageCompound(page))
1105 return 0;
1107 * If already mapped, we don't have to account.
1108 * If page cache, page->mapping has address_space.
1109 * But page->mapping may have out-of-use anon_vma pointer,
1110 * detecit it by PageAnon() check. newly-mapped-anon's page->mapping
1111 * is NULL.
1113 if (page_mapped(page) || (page->mapping && !PageAnon(page)))
1114 return 0;
1115 if (unlikely(!mm))
1116 mm = &init_mm;
1117 return mem_cgroup_charge_common(page, mm, gfp_mask,
1118 MEM_CGROUP_CHARGE_TYPE_MAPPED, NULL);
1121 int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
1122 gfp_t gfp_mask)
1124 struct mem_cgroup *mem = NULL;
1125 int ret;
1127 if (mem_cgroup_disabled())
1128 return 0;
1129 if (PageCompound(page))
1130 return 0;
1132 * Corner case handling. This is called from add_to_page_cache()
1133 * in usual. But some FS (shmem) precharges this page before calling it
1134 * and call add_to_page_cache() with GFP_NOWAIT.
1136 * For GFP_NOWAIT case, the page may be pre-charged before calling
1137 * add_to_page_cache(). (See shmem.c) check it here and avoid to call
1138 * charge twice. (It works but has to pay a bit larger cost.)
1139 * And when the page is SwapCache, it should take swap information
1140 * into account. This is under lock_page() now.
1142 if (!(gfp_mask & __GFP_WAIT)) {
1143 struct page_cgroup *pc;
1146 pc = lookup_page_cgroup(page);
1147 if (!pc)
1148 return 0;
1149 lock_page_cgroup(pc);
1150 if (PageCgroupUsed(pc)) {
1151 unlock_page_cgroup(pc);
1152 return 0;
1154 unlock_page_cgroup(pc);
1157 if (do_swap_account && PageSwapCache(page)) {
1158 mem = try_get_mem_cgroup_from_swapcache(page);
1159 if (mem)
1160 mm = NULL;
1161 else
1162 mem = NULL;
1163 /* SwapCache may be still linked to LRU now. */
1164 mem_cgroup_lru_del_before_commit_swapcache(page);
1167 if (unlikely(!mm && !mem))
1168 mm = &init_mm;
1170 if (page_is_file_cache(page))
1171 return mem_cgroup_charge_common(page, mm, gfp_mask,
1172 MEM_CGROUP_CHARGE_TYPE_CACHE, NULL);
1174 ret = mem_cgroup_charge_common(page, mm, gfp_mask,
1175 MEM_CGROUP_CHARGE_TYPE_SHMEM, mem);
1176 if (mem)
1177 css_put(&mem->css);
1178 if (PageSwapCache(page))
1179 mem_cgroup_lru_add_after_commit_swapcache(page);
1181 if (do_swap_account && !ret && PageSwapCache(page)) {
1182 swp_entry_t ent = {.val = page_private(page)};
1183 /* avoid double counting */
1184 mem = swap_cgroup_record(ent, NULL);
1185 if (mem) {
1186 res_counter_uncharge(&mem->memsw, PAGE_SIZE);
1187 mem_cgroup_put(mem);
1190 return ret;
1194 * While swap-in, try_charge -> commit or cancel, the page is locked.
1195 * And when try_charge() successfully returns, one refcnt to memcg without
1196 * struct page_cgroup is aquired. This refcnt will be cumsumed by
1197 * "commit()" or removed by "cancel()"
1199 int mem_cgroup_try_charge_swapin(struct mm_struct *mm,
1200 struct page *page,
1201 gfp_t mask, struct mem_cgroup **ptr)
1203 struct mem_cgroup *mem;
1204 int ret;
1206 if (mem_cgroup_disabled())
1207 return 0;
1209 if (!do_swap_account)
1210 goto charge_cur_mm;
1212 * A racing thread's fault, or swapoff, may have already updated
1213 * the pte, and even removed page from swap cache: return success
1214 * to go on to do_swap_page()'s pte_same() test, which should fail.
1216 if (!PageSwapCache(page))
1217 return 0;
1218 mem = try_get_mem_cgroup_from_swapcache(page);
1219 if (!mem)
1220 goto charge_cur_mm;
1221 *ptr = mem;
1222 ret = __mem_cgroup_try_charge(NULL, mask, ptr, true);
1223 /* drop extra refcnt from tryget */
1224 css_put(&mem->css);
1225 return ret;
1226 charge_cur_mm:
1227 if (unlikely(!mm))
1228 mm = &init_mm;
1229 return __mem_cgroup_try_charge(mm, mask, ptr, true);
1232 void mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr)
1234 struct page_cgroup *pc;
1236 if (mem_cgroup_disabled())
1237 return;
1238 if (!ptr)
1239 return;
1240 pc = lookup_page_cgroup(page);
1241 mem_cgroup_lru_del_before_commit_swapcache(page);
1242 __mem_cgroup_commit_charge(ptr, pc, MEM_CGROUP_CHARGE_TYPE_MAPPED);
1243 mem_cgroup_lru_add_after_commit_swapcache(page);
1245 * Now swap is on-memory. This means this page may be
1246 * counted both as mem and swap....double count.
1247 * Fix it by uncharging from memsw. Basically, this SwapCache is stable
1248 * under lock_page(). But in do_swap_page()::memory.c, reuse_swap_page()
1249 * may call delete_from_swap_cache() before reach here.
1251 if (do_swap_account && PageSwapCache(page)) {
1252 swp_entry_t ent = {.val = page_private(page)};
1253 struct mem_cgroup *memcg;
1254 memcg = swap_cgroup_record(ent, NULL);
1255 if (memcg) {
1256 res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
1257 mem_cgroup_put(memcg);
1261 /* add this page(page_cgroup) to the LRU we want. */
1265 void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *mem)
1267 if (mem_cgroup_disabled())
1268 return;
1269 if (!mem)
1270 return;
1271 res_counter_uncharge(&mem->res, PAGE_SIZE);
1272 if (do_swap_account)
1273 res_counter_uncharge(&mem->memsw, PAGE_SIZE);
1274 css_put(&mem->css);
1279 * uncharge if !page_mapped(page)
1281 static struct mem_cgroup *
1282 __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
1284 struct page_cgroup *pc;
1285 struct mem_cgroup *mem = NULL;
1286 struct mem_cgroup_per_zone *mz;
1288 if (mem_cgroup_disabled())
1289 return NULL;
1291 if (PageSwapCache(page))
1292 return NULL;
1295 * Check if our page_cgroup is valid
1297 pc = lookup_page_cgroup(page);
1298 if (unlikely(!pc || !PageCgroupUsed(pc)))
1299 return NULL;
1301 lock_page_cgroup(pc);
1303 mem = pc->mem_cgroup;
1305 if (!PageCgroupUsed(pc))
1306 goto unlock_out;
1308 switch (ctype) {
1309 case MEM_CGROUP_CHARGE_TYPE_MAPPED:
1310 if (page_mapped(page))
1311 goto unlock_out;
1312 break;
1313 case MEM_CGROUP_CHARGE_TYPE_SWAPOUT:
1314 if (!PageAnon(page)) { /* Shared memory */
1315 if (page->mapping && !page_is_file_cache(page))
1316 goto unlock_out;
1317 } else if (page_mapped(page)) /* Anon */
1318 goto unlock_out;
1319 break;
1320 default:
1321 break;
1324 res_counter_uncharge(&mem->res, PAGE_SIZE);
1325 if (do_swap_account && (ctype != MEM_CGROUP_CHARGE_TYPE_SWAPOUT))
1326 res_counter_uncharge(&mem->memsw, PAGE_SIZE);
1328 mem_cgroup_charge_statistics(mem, pc, false);
1329 ClearPageCgroupUsed(pc);
1331 * pc->mem_cgroup is not cleared here. It will be accessed when it's
1332 * freed from LRU. This is safe because uncharged page is expected not
1333 * to be reused (freed soon). Exception is SwapCache, it's handled by
1334 * special functions.
1337 mz = page_cgroup_zoneinfo(pc);
1338 unlock_page_cgroup(pc);
1340 /* at swapout, this memcg will be accessed to record to swap */
1341 if (ctype != MEM_CGROUP_CHARGE_TYPE_SWAPOUT)
1342 css_put(&mem->css);
1344 return mem;
1346 unlock_out:
1347 unlock_page_cgroup(pc);
1348 return NULL;
1351 void mem_cgroup_uncharge_page(struct page *page)
1353 /* early check. */
1354 if (page_mapped(page))
1355 return;
1356 if (page->mapping && !PageAnon(page))
1357 return;
1358 __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_MAPPED);
1361 void mem_cgroup_uncharge_cache_page(struct page *page)
1363 VM_BUG_ON(page_mapped(page));
1364 VM_BUG_ON(page->mapping);
1365 __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE);
1369 * called from __delete_from_swap_cache() and drop "page" account.
1370 * memcg information is recorded to swap_cgroup of "ent"
1372 void mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent)
1374 struct mem_cgroup *memcg;
1376 memcg = __mem_cgroup_uncharge_common(page,
1377 MEM_CGROUP_CHARGE_TYPE_SWAPOUT);
1378 /* record memcg information */
1379 if (do_swap_account && memcg) {
1380 swap_cgroup_record(ent, memcg);
1381 mem_cgroup_get(memcg);
1383 if (memcg)
1384 css_put(&memcg->css);
1387 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
1389 * called from swap_entry_free(). remove record in swap_cgroup and
1390 * uncharge "memsw" account.
1392 void mem_cgroup_uncharge_swap(swp_entry_t ent)
1394 struct mem_cgroup *memcg;
1396 if (!do_swap_account)
1397 return;
1399 memcg = swap_cgroup_record(ent, NULL);
1400 if (memcg) {
1401 res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
1402 mem_cgroup_put(memcg);
1405 #endif
1408 * Before starting migration, account PAGE_SIZE to mem_cgroup that the old
1409 * page belongs to.
1411 int mem_cgroup_prepare_migration(struct page *page, struct mem_cgroup **ptr)
1413 struct page_cgroup *pc;
1414 struct mem_cgroup *mem = NULL;
1415 int ret = 0;
1417 if (mem_cgroup_disabled())
1418 return 0;
1420 pc = lookup_page_cgroup(page);
1421 lock_page_cgroup(pc);
1422 if (PageCgroupUsed(pc)) {
1423 mem = pc->mem_cgroup;
1424 css_get(&mem->css);
1426 unlock_page_cgroup(pc);
1428 if (mem) {
1429 ret = __mem_cgroup_try_charge(NULL, GFP_KERNEL, &mem, false);
1430 css_put(&mem->css);
1432 *ptr = mem;
1433 return ret;
1436 /* remove redundant charge if migration failed*/
1437 void mem_cgroup_end_migration(struct mem_cgroup *mem,
1438 struct page *oldpage, struct page *newpage)
1440 struct page *target, *unused;
1441 struct page_cgroup *pc;
1442 enum charge_type ctype;
1444 if (!mem)
1445 return;
1447 /* at migration success, oldpage->mapping is NULL. */
1448 if (oldpage->mapping) {
1449 target = oldpage;
1450 unused = NULL;
1451 } else {
1452 target = newpage;
1453 unused = oldpage;
1456 if (PageAnon(target))
1457 ctype = MEM_CGROUP_CHARGE_TYPE_MAPPED;
1458 else if (page_is_file_cache(target))
1459 ctype = MEM_CGROUP_CHARGE_TYPE_CACHE;
1460 else
1461 ctype = MEM_CGROUP_CHARGE_TYPE_SHMEM;
1463 /* unused page is not on radix-tree now. */
1464 if (unused)
1465 __mem_cgroup_uncharge_common(unused, ctype);
1467 pc = lookup_page_cgroup(target);
1469 * __mem_cgroup_commit_charge() check PCG_USED bit of page_cgroup.
1470 * So, double-counting is effectively avoided.
1472 __mem_cgroup_commit_charge(mem, pc, ctype);
1475 * Both of oldpage and newpage are still under lock_page().
1476 * Then, we don't have to care about race in radix-tree.
1477 * But we have to be careful that this page is unmapped or not.
1479 * There is a case for !page_mapped(). At the start of
1480 * migration, oldpage was mapped. But now, it's zapped.
1481 * But we know *target* page is not freed/reused under us.
1482 * mem_cgroup_uncharge_page() does all necessary checks.
1484 if (ctype == MEM_CGROUP_CHARGE_TYPE_MAPPED)
1485 mem_cgroup_uncharge_page(target);
1489 * A call to try to shrink memory usage under specified resource controller.
1490 * This is typically used for page reclaiming for shmem for reducing side
1491 * effect of page allocation from shmem, which is used by some mem_cgroup.
1493 int mem_cgroup_shrink_usage(struct page *page,
1494 struct mm_struct *mm,
1495 gfp_t gfp_mask)
1497 struct mem_cgroup *mem = NULL;
1498 int progress = 0;
1499 int retry = MEM_CGROUP_RECLAIM_RETRIES;
1501 if (mem_cgroup_disabled())
1502 return 0;
1503 if (page)
1504 mem = try_get_mem_cgroup_from_swapcache(page);
1505 if (!mem && mm)
1506 mem = try_get_mem_cgroup_from_mm(mm);
1507 if (unlikely(!mem))
1508 return 0;
1510 do {
1511 progress = mem_cgroup_hierarchical_reclaim(mem, gfp_mask, true);
1512 progress += mem_cgroup_check_under_limit(mem);
1513 } while (!progress && --retry);
1515 css_put(&mem->css);
1516 if (!retry)
1517 return -ENOMEM;
1518 return 0;
1521 static DEFINE_MUTEX(set_limit_mutex);
1523 static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
1524 unsigned long long val)
1527 int retry_count = MEM_CGROUP_RECLAIM_RETRIES;
1528 int progress;
1529 u64 memswlimit;
1530 int ret = 0;
1532 while (retry_count) {
1533 if (signal_pending(current)) {
1534 ret = -EINTR;
1535 break;
1538 * Rather than hide all in some function, I do this in
1539 * open coded manner. You see what this really does.
1540 * We have to guarantee mem->res.limit < mem->memsw.limit.
1542 mutex_lock(&set_limit_mutex);
1543 memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
1544 if (memswlimit < val) {
1545 ret = -EINVAL;
1546 mutex_unlock(&set_limit_mutex);
1547 break;
1549 ret = res_counter_set_limit(&memcg->res, val);
1550 mutex_unlock(&set_limit_mutex);
1552 if (!ret)
1553 break;
1555 progress = mem_cgroup_hierarchical_reclaim(memcg, GFP_KERNEL,
1556 false);
1557 if (!progress) retry_count--;
1560 return ret;
1563 int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
1564 unsigned long long val)
1566 int retry_count = MEM_CGROUP_RECLAIM_RETRIES;
1567 u64 memlimit, oldusage, curusage;
1568 int ret;
1570 if (!do_swap_account)
1571 return -EINVAL;
1573 while (retry_count) {
1574 if (signal_pending(current)) {
1575 ret = -EINTR;
1576 break;
1579 * Rather than hide all in some function, I do this in
1580 * open coded manner. You see what this really does.
1581 * We have to guarantee mem->res.limit < mem->memsw.limit.
1583 mutex_lock(&set_limit_mutex);
1584 memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT);
1585 if (memlimit > val) {
1586 ret = -EINVAL;
1587 mutex_unlock(&set_limit_mutex);
1588 break;
1590 ret = res_counter_set_limit(&memcg->memsw, val);
1591 mutex_unlock(&set_limit_mutex);
1593 if (!ret)
1594 break;
1596 oldusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
1597 mem_cgroup_hierarchical_reclaim(memcg, GFP_KERNEL, true);
1598 curusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
1599 if (curusage >= oldusage)
1600 retry_count--;
1602 return ret;
1606 * This routine traverse page_cgroup in given list and drop them all.
1607 * *And* this routine doesn't reclaim page itself, just removes page_cgroup.
1609 static int mem_cgroup_force_empty_list(struct mem_cgroup *mem,
1610 int node, int zid, enum lru_list lru)
1612 struct zone *zone;
1613 struct mem_cgroup_per_zone *mz;
1614 struct page_cgroup *pc, *busy;
1615 unsigned long flags, loop;
1616 struct list_head *list;
1617 int ret = 0;
1619 zone = &NODE_DATA(node)->node_zones[zid];
1620 mz = mem_cgroup_zoneinfo(mem, node, zid);
1621 list = &mz->lists[lru];
1623 loop = MEM_CGROUP_ZSTAT(mz, lru);
1624 /* give some margin against EBUSY etc...*/
1625 loop += 256;
1626 busy = NULL;
1627 while (loop--) {
1628 ret = 0;
1629 spin_lock_irqsave(&zone->lru_lock, flags);
1630 if (list_empty(list)) {
1631 spin_unlock_irqrestore(&zone->lru_lock, flags);
1632 break;
1634 pc = list_entry(list->prev, struct page_cgroup, lru);
1635 if (busy == pc) {
1636 list_move(&pc->lru, list);
1637 busy = 0;
1638 spin_unlock_irqrestore(&zone->lru_lock, flags);
1639 continue;
1641 spin_unlock_irqrestore(&zone->lru_lock, flags);
1643 ret = mem_cgroup_move_parent(pc, mem, GFP_KERNEL);
1644 if (ret == -ENOMEM)
1645 break;
1647 if (ret == -EBUSY || ret == -EINVAL) {
1648 /* found lock contention or "pc" is obsolete. */
1649 busy = pc;
1650 cond_resched();
1651 } else
1652 busy = NULL;
1655 if (!ret && !list_empty(list))
1656 return -EBUSY;
1657 return ret;
1661 * make mem_cgroup's charge to be 0 if there is no task.
1662 * This enables deleting this mem_cgroup.
1664 static int mem_cgroup_force_empty(struct mem_cgroup *mem, bool free_all)
1666 int ret;
1667 int node, zid, shrink;
1668 int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
1669 struct cgroup *cgrp = mem->css.cgroup;
1671 css_get(&mem->css);
1673 shrink = 0;
1674 /* should free all ? */
1675 if (free_all)
1676 goto try_to_free;
1677 move_account:
1678 while (mem->res.usage > 0) {
1679 ret = -EBUSY;
1680 if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children))
1681 goto out;
1682 ret = -EINTR;
1683 if (signal_pending(current))
1684 goto out;
1685 /* This is for making all *used* pages to be on LRU. */
1686 lru_add_drain_all();
1687 ret = 0;
1688 for_each_node_state(node, N_HIGH_MEMORY) {
1689 for (zid = 0; !ret && zid < MAX_NR_ZONES; zid++) {
1690 enum lru_list l;
1691 for_each_lru(l) {
1692 ret = mem_cgroup_force_empty_list(mem,
1693 node, zid, l);
1694 if (ret)
1695 break;
1698 if (ret)
1699 break;
1701 /* it seems parent cgroup doesn't have enough mem */
1702 if (ret == -ENOMEM)
1703 goto try_to_free;
1704 cond_resched();
1706 ret = 0;
1707 out:
1708 css_put(&mem->css);
1709 return ret;
1711 try_to_free:
1712 /* returns EBUSY if there is a task or if we come here twice. */
1713 if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children) || shrink) {
1714 ret = -EBUSY;
1715 goto out;
1717 /* we call try-to-free pages for make this cgroup empty */
1718 lru_add_drain_all();
1719 /* try to free all pages in this cgroup */
1720 shrink = 1;
1721 while (nr_retries && mem->res.usage > 0) {
1722 int progress;
1724 if (signal_pending(current)) {
1725 ret = -EINTR;
1726 goto out;
1728 progress = try_to_free_mem_cgroup_pages(mem, GFP_KERNEL,
1729 false, get_swappiness(mem));
1730 if (!progress) {
1731 nr_retries--;
1732 /* maybe some writeback is necessary */
1733 congestion_wait(WRITE, HZ/10);
1737 lru_add_drain();
1738 /* try move_account...there may be some *locked* pages. */
1739 if (mem->res.usage)
1740 goto move_account;
1741 ret = 0;
1742 goto out;
1745 int mem_cgroup_force_empty_write(struct cgroup *cont, unsigned int event)
1747 return mem_cgroup_force_empty(mem_cgroup_from_cont(cont), true);
1751 static u64 mem_cgroup_hierarchy_read(struct cgroup *cont, struct cftype *cft)
1753 return mem_cgroup_from_cont(cont)->use_hierarchy;
1756 static int mem_cgroup_hierarchy_write(struct cgroup *cont, struct cftype *cft,
1757 u64 val)
1759 int retval = 0;
1760 struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
1761 struct cgroup *parent = cont->parent;
1762 struct mem_cgroup *parent_mem = NULL;
1764 if (parent)
1765 parent_mem = mem_cgroup_from_cont(parent);
1767 cgroup_lock();
1769 * If parent's use_hiearchy is set, we can't make any modifications
1770 * in the child subtrees. If it is unset, then the change can
1771 * occur, provided the current cgroup has no children.
1773 * For the root cgroup, parent_mem is NULL, we allow value to be
1774 * set if there are no children.
1776 if ((!parent_mem || !parent_mem->use_hierarchy) &&
1777 (val == 1 || val == 0)) {
1778 if (list_empty(&cont->children))
1779 mem->use_hierarchy = val;
1780 else
1781 retval = -EBUSY;
1782 } else
1783 retval = -EINVAL;
1784 cgroup_unlock();
1786 return retval;
1789 static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft)
1791 struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
1792 u64 val = 0;
1793 int type, name;
1795 type = MEMFILE_TYPE(cft->private);
1796 name = MEMFILE_ATTR(cft->private);
1797 switch (type) {
1798 case _MEM:
1799 val = res_counter_read_u64(&mem->res, name);
1800 break;
1801 case _MEMSWAP:
1802 if (do_swap_account)
1803 val = res_counter_read_u64(&mem->memsw, name);
1804 break;
1805 default:
1806 BUG();
1807 break;
1809 return val;
1812 * The user of this function is...
1813 * RES_LIMIT.
1815 static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
1816 const char *buffer)
1818 struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
1819 int type, name;
1820 unsigned long long val;
1821 int ret;
1823 type = MEMFILE_TYPE(cft->private);
1824 name = MEMFILE_ATTR(cft->private);
1825 switch (name) {
1826 case RES_LIMIT:
1827 /* This function does all necessary parse...reuse it */
1828 ret = res_counter_memparse_write_strategy(buffer, &val);
1829 if (ret)
1830 break;
1831 if (type == _MEM)
1832 ret = mem_cgroup_resize_limit(memcg, val);
1833 else
1834 ret = mem_cgroup_resize_memsw_limit(memcg, val);
1835 break;
1836 default:
1837 ret = -EINVAL; /* should be BUG() ? */
1838 break;
1840 return ret;
1843 static void memcg_get_hierarchical_limit(struct mem_cgroup *memcg,
1844 unsigned long long *mem_limit, unsigned long long *memsw_limit)
1846 struct cgroup *cgroup;
1847 unsigned long long min_limit, min_memsw_limit, tmp;
1849 min_limit = res_counter_read_u64(&memcg->res, RES_LIMIT);
1850 min_memsw_limit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
1851 cgroup = memcg->css.cgroup;
1852 if (!memcg->use_hierarchy)
1853 goto out;
1855 while (cgroup->parent) {
1856 cgroup = cgroup->parent;
1857 memcg = mem_cgroup_from_cont(cgroup);
1858 if (!memcg->use_hierarchy)
1859 break;
1860 tmp = res_counter_read_u64(&memcg->res, RES_LIMIT);
1861 min_limit = min(min_limit, tmp);
1862 tmp = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
1863 min_memsw_limit = min(min_memsw_limit, tmp);
1865 out:
1866 *mem_limit = min_limit;
1867 *memsw_limit = min_memsw_limit;
1868 return;
1871 static int mem_cgroup_reset(struct cgroup *cont, unsigned int event)
1873 struct mem_cgroup *mem;
1874 int type, name;
1876 mem = mem_cgroup_from_cont(cont);
1877 type = MEMFILE_TYPE(event);
1878 name = MEMFILE_ATTR(event);
1879 switch (name) {
1880 case RES_MAX_USAGE:
1881 if (type == _MEM)
1882 res_counter_reset_max(&mem->res);
1883 else
1884 res_counter_reset_max(&mem->memsw);
1885 break;
1886 case RES_FAILCNT:
1887 if (type == _MEM)
1888 res_counter_reset_failcnt(&mem->res);
1889 else
1890 res_counter_reset_failcnt(&mem->memsw);
1891 break;
1893 return 0;
1896 static const struct mem_cgroup_stat_desc {
1897 const char *msg;
1898 u64 unit;
1899 } mem_cgroup_stat_desc[] = {
1900 [MEM_CGROUP_STAT_CACHE] = { "cache", PAGE_SIZE, },
1901 [MEM_CGROUP_STAT_RSS] = { "rss", PAGE_SIZE, },
1902 [MEM_CGROUP_STAT_PGPGIN_COUNT] = {"pgpgin", 1, },
1903 [MEM_CGROUP_STAT_PGPGOUT_COUNT] = {"pgpgout", 1, },
1906 static int mem_control_stat_show(struct cgroup *cont, struct cftype *cft,
1907 struct cgroup_map_cb *cb)
1909 struct mem_cgroup *mem_cont = mem_cgroup_from_cont(cont);
1910 struct mem_cgroup_stat *stat = &mem_cont->stat;
1911 int i;
1913 for (i = 0; i < ARRAY_SIZE(stat->cpustat[0].count); i++) {
1914 s64 val;
1916 val = mem_cgroup_read_stat(stat, i);
1917 val *= mem_cgroup_stat_desc[i].unit;
1918 cb->fill(cb, mem_cgroup_stat_desc[i].msg, val);
1920 /* showing # of active pages */
1922 unsigned long active_anon, inactive_anon;
1923 unsigned long active_file, inactive_file;
1924 unsigned long unevictable;
1926 inactive_anon = mem_cgroup_get_all_zonestat(mem_cont,
1927 LRU_INACTIVE_ANON);
1928 active_anon = mem_cgroup_get_all_zonestat(mem_cont,
1929 LRU_ACTIVE_ANON);
1930 inactive_file = mem_cgroup_get_all_zonestat(mem_cont,
1931 LRU_INACTIVE_FILE);
1932 active_file = mem_cgroup_get_all_zonestat(mem_cont,
1933 LRU_ACTIVE_FILE);
1934 unevictable = mem_cgroup_get_all_zonestat(mem_cont,
1935 LRU_UNEVICTABLE);
1937 cb->fill(cb, "active_anon", (active_anon) * PAGE_SIZE);
1938 cb->fill(cb, "inactive_anon", (inactive_anon) * PAGE_SIZE);
1939 cb->fill(cb, "active_file", (active_file) * PAGE_SIZE);
1940 cb->fill(cb, "inactive_file", (inactive_file) * PAGE_SIZE);
1941 cb->fill(cb, "unevictable", unevictable * PAGE_SIZE);
1945 unsigned long long limit, memsw_limit;
1946 memcg_get_hierarchical_limit(mem_cont, &limit, &memsw_limit);
1947 cb->fill(cb, "hierarchical_memory_limit", limit);
1948 if (do_swap_account)
1949 cb->fill(cb, "hierarchical_memsw_limit", memsw_limit);
1952 #ifdef CONFIG_DEBUG_VM
1953 cb->fill(cb, "inactive_ratio", calc_inactive_ratio(mem_cont, NULL));
1956 int nid, zid;
1957 struct mem_cgroup_per_zone *mz;
1958 unsigned long recent_rotated[2] = {0, 0};
1959 unsigned long recent_scanned[2] = {0, 0};
1961 for_each_online_node(nid)
1962 for (zid = 0; zid < MAX_NR_ZONES; zid++) {
1963 mz = mem_cgroup_zoneinfo(mem_cont, nid, zid);
1965 recent_rotated[0] +=
1966 mz->reclaim_stat.recent_rotated[0];
1967 recent_rotated[1] +=
1968 mz->reclaim_stat.recent_rotated[1];
1969 recent_scanned[0] +=
1970 mz->reclaim_stat.recent_scanned[0];
1971 recent_scanned[1] +=
1972 mz->reclaim_stat.recent_scanned[1];
1974 cb->fill(cb, "recent_rotated_anon", recent_rotated[0]);
1975 cb->fill(cb, "recent_rotated_file", recent_rotated[1]);
1976 cb->fill(cb, "recent_scanned_anon", recent_scanned[0]);
1977 cb->fill(cb, "recent_scanned_file", recent_scanned[1]);
1979 #endif
1981 return 0;
1984 static u64 mem_cgroup_swappiness_read(struct cgroup *cgrp, struct cftype *cft)
1986 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
1988 return get_swappiness(memcg);
1991 static int mem_cgroup_swappiness_write(struct cgroup *cgrp, struct cftype *cft,
1992 u64 val)
1994 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
1995 struct mem_cgroup *parent;
1997 if (val > 100)
1998 return -EINVAL;
2000 if (cgrp->parent == NULL)
2001 return -EINVAL;
2003 parent = mem_cgroup_from_cont(cgrp->parent);
2005 cgroup_lock();
2007 /* If under hierarchy, only empty-root can set this value */
2008 if ((parent->use_hierarchy) ||
2009 (memcg->use_hierarchy && !list_empty(&cgrp->children))) {
2010 cgroup_unlock();
2011 return -EINVAL;
2014 spin_lock(&memcg->reclaim_param_lock);
2015 memcg->swappiness = val;
2016 spin_unlock(&memcg->reclaim_param_lock);
2018 cgroup_unlock();
2020 return 0;
2024 static struct cftype mem_cgroup_files[] = {
2026 .name = "usage_in_bytes",
2027 .private = MEMFILE_PRIVATE(_MEM, RES_USAGE),
2028 .read_u64 = mem_cgroup_read,
2031 .name = "max_usage_in_bytes",
2032 .private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE),
2033 .trigger = mem_cgroup_reset,
2034 .read_u64 = mem_cgroup_read,
2037 .name = "limit_in_bytes",
2038 .private = MEMFILE_PRIVATE(_MEM, RES_LIMIT),
2039 .write_string = mem_cgroup_write,
2040 .read_u64 = mem_cgroup_read,
2043 .name = "failcnt",
2044 .private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT),
2045 .trigger = mem_cgroup_reset,
2046 .read_u64 = mem_cgroup_read,
2049 .name = "stat",
2050 .read_map = mem_control_stat_show,
2053 .name = "force_empty",
2054 .trigger = mem_cgroup_force_empty_write,
2057 .name = "use_hierarchy",
2058 .write_u64 = mem_cgroup_hierarchy_write,
2059 .read_u64 = mem_cgroup_hierarchy_read,
2062 .name = "swappiness",
2063 .read_u64 = mem_cgroup_swappiness_read,
2064 .write_u64 = mem_cgroup_swappiness_write,
2068 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
2069 static struct cftype memsw_cgroup_files[] = {
2071 .name = "memsw.usage_in_bytes",
2072 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE),
2073 .read_u64 = mem_cgroup_read,
2076 .name = "memsw.max_usage_in_bytes",
2077 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE),
2078 .trigger = mem_cgroup_reset,
2079 .read_u64 = mem_cgroup_read,
2082 .name = "memsw.limit_in_bytes",
2083 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT),
2084 .write_string = mem_cgroup_write,
2085 .read_u64 = mem_cgroup_read,
2088 .name = "memsw.failcnt",
2089 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT),
2090 .trigger = mem_cgroup_reset,
2091 .read_u64 = mem_cgroup_read,
2095 static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss)
2097 if (!do_swap_account)
2098 return 0;
2099 return cgroup_add_files(cont, ss, memsw_cgroup_files,
2100 ARRAY_SIZE(memsw_cgroup_files));
2102 #else
2103 static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss)
2105 return 0;
2107 #endif
2109 static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
2111 struct mem_cgroup_per_node *pn;
2112 struct mem_cgroup_per_zone *mz;
2113 enum lru_list l;
2114 int zone, tmp = node;
2116 * This routine is called against possible nodes.
2117 * But it's BUG to call kmalloc() against offline node.
2119 * TODO: this routine can waste much memory for nodes which will
2120 * never be onlined. It's better to use memory hotplug callback
2121 * function.
2123 if (!node_state(node, N_NORMAL_MEMORY))
2124 tmp = -1;
2125 pn = kmalloc_node(sizeof(*pn), GFP_KERNEL, tmp);
2126 if (!pn)
2127 return 1;
2129 mem->info.nodeinfo[node] = pn;
2130 memset(pn, 0, sizeof(*pn));
2132 for (zone = 0; zone < MAX_NR_ZONES; zone++) {
2133 mz = &pn->zoneinfo[zone];
2134 for_each_lru(l)
2135 INIT_LIST_HEAD(&mz->lists[l]);
2137 return 0;
2140 static void free_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
2142 kfree(mem->info.nodeinfo[node]);
2145 static int mem_cgroup_size(void)
2147 int cpustat_size = nr_cpu_ids * sizeof(struct mem_cgroup_stat_cpu);
2148 return sizeof(struct mem_cgroup) + cpustat_size;
2151 static struct mem_cgroup *mem_cgroup_alloc(void)
2153 struct mem_cgroup *mem;
2154 int size = mem_cgroup_size();
2156 if (size < PAGE_SIZE)
2157 mem = kmalloc(size, GFP_KERNEL);
2158 else
2159 mem = vmalloc(size);
2161 if (mem)
2162 memset(mem, 0, size);
2163 return mem;
2167 * At destroying mem_cgroup, references from swap_cgroup can remain.
2168 * (scanning all at force_empty is too costly...)
2170 * Instead of clearing all references at force_empty, we remember
2171 * the number of reference from swap_cgroup and free mem_cgroup when
2172 * it goes down to 0.
2174 * Removal of cgroup itself succeeds regardless of refs from swap.
2177 static void __mem_cgroup_free(struct mem_cgroup *mem)
2179 int node;
2181 for_each_node_state(node, N_POSSIBLE)
2182 free_mem_cgroup_per_zone_info(mem, node);
2184 if (mem_cgroup_size() < PAGE_SIZE)
2185 kfree(mem);
2186 else
2187 vfree(mem);
2190 static void mem_cgroup_get(struct mem_cgroup *mem)
2192 atomic_inc(&mem->refcnt);
2195 static void mem_cgroup_put(struct mem_cgroup *mem)
2197 if (atomic_dec_and_test(&mem->refcnt)) {
2198 struct mem_cgroup *parent = parent_mem_cgroup(mem);
2199 __mem_cgroup_free(mem);
2200 if (parent)
2201 mem_cgroup_put(parent);
2206 * Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled.
2208 static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem)
2210 if (!mem->res.parent)
2211 return NULL;
2212 return mem_cgroup_from_res_counter(mem->res.parent, res);
2215 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
2216 static void __init enable_swap_cgroup(void)
2218 if (!mem_cgroup_disabled() && really_do_swap_account)
2219 do_swap_account = 1;
2221 #else
2222 static void __init enable_swap_cgroup(void)
2225 #endif
2227 static struct cgroup_subsys_state * __ref
2228 mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
2230 struct mem_cgroup *mem, *parent;
2231 int node;
2233 mem = mem_cgroup_alloc();
2234 if (!mem)
2235 return ERR_PTR(-ENOMEM);
2237 for_each_node_state(node, N_POSSIBLE)
2238 if (alloc_mem_cgroup_per_zone_info(mem, node))
2239 goto free_out;
2240 /* root ? */
2241 if (cont->parent == NULL) {
2242 enable_swap_cgroup();
2243 parent = NULL;
2244 } else {
2245 parent = mem_cgroup_from_cont(cont->parent);
2246 mem->use_hierarchy = parent->use_hierarchy;
2249 if (parent && parent->use_hierarchy) {
2250 res_counter_init(&mem->res, &parent->res);
2251 res_counter_init(&mem->memsw, &parent->memsw);
2253 * We increment refcnt of the parent to ensure that we can
2254 * safely access it on res_counter_charge/uncharge.
2255 * This refcnt will be decremented when freeing this
2256 * mem_cgroup(see mem_cgroup_put).
2258 mem_cgroup_get(parent);
2259 } else {
2260 res_counter_init(&mem->res, NULL);
2261 res_counter_init(&mem->memsw, NULL);
2263 mem->last_scanned_child = NULL;
2264 spin_lock_init(&mem->reclaim_param_lock);
2266 if (parent)
2267 mem->swappiness = get_swappiness(parent);
2268 atomic_set(&mem->refcnt, 1);
2269 return &mem->css;
2270 free_out:
2271 __mem_cgroup_free(mem);
2272 return ERR_PTR(-ENOMEM);
2275 static void mem_cgroup_pre_destroy(struct cgroup_subsys *ss,
2276 struct cgroup *cont)
2278 struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
2279 mem_cgroup_force_empty(mem, false);
2282 static void mem_cgroup_destroy(struct cgroup_subsys *ss,
2283 struct cgroup *cont)
2285 struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
2286 struct mem_cgroup *last_scanned_child = mem->last_scanned_child;
2288 if (last_scanned_child) {
2289 VM_BUG_ON(!mem_cgroup_is_obsolete(last_scanned_child));
2290 mem_cgroup_put(last_scanned_child);
2292 mem_cgroup_put(mem);
2295 static int mem_cgroup_populate(struct cgroup_subsys *ss,
2296 struct cgroup *cont)
2298 int ret;
2300 ret = cgroup_add_files(cont, ss, mem_cgroup_files,
2301 ARRAY_SIZE(mem_cgroup_files));
2303 if (!ret)
2304 ret = register_memsw_files(cont, ss);
2305 return ret;
2308 static void mem_cgroup_move_task(struct cgroup_subsys *ss,
2309 struct cgroup *cont,
2310 struct cgroup *old_cont,
2311 struct task_struct *p)
2313 mutex_lock(&memcg_tasklist);
2315 * FIXME: It's better to move charges of this process from old
2316 * memcg to new memcg. But it's just on TODO-List now.
2318 mutex_unlock(&memcg_tasklist);
2321 struct cgroup_subsys mem_cgroup_subsys = {
2322 .name = "memory",
2323 .subsys_id = mem_cgroup_subsys_id,
2324 .create = mem_cgroup_create,
2325 .pre_destroy = mem_cgroup_pre_destroy,
2326 .destroy = mem_cgroup_destroy,
2327 .populate = mem_cgroup_populate,
2328 .attach = mem_cgroup_move_task,
2329 .early_init = 0,
2332 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
2334 static int __init disable_swap_account(char *s)
2336 really_do_swap_account = 0;
2337 return 1;
2339 __setup("noswapaccount", disable_swap_account);
2340 #endif