memcg: some modification to softlimit under hierarchical memory reclaim.
[linux-2.6.git] / mm / memcontrol.c
1 /* memcontrol.c - Memory Controller
2  *
3  * Copyright IBM Corporation, 2007
4  * Author Balbir Singh <balbir@linux.vnet.ibm.com>
5  *
6  * Copyright 2007 OpenVZ SWsoft Inc
7  * Author: Pavel Emelianov <xemul@openvz.org>
8  *
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.
13  *
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.
18  */
19
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/limits.h>
31 #include <linux/mutex.h>
32 #include <linux/rbtree.h>
33 #include <linux/slab.h>
34 #include <linux/swap.h>
35 #include <linux/spinlock.h>
36 #include <linux/fs.h>
37 #include <linux/seq_file.h>
38 #include <linux/vmalloc.h>
39 #include <linux/mm_inline.h>
40 #include <linux/page_cgroup.h>
41 #include "internal.h"
42
43 #include <asm/uaccess.h>
44
45 struct cgroup_subsys mem_cgroup_subsys __read_mostly;
46 #define MEM_CGROUP_RECLAIM_RETRIES      5
47 struct mem_cgroup *root_mem_cgroup __read_mostly;
48
49 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
50 /* Turned on only when memory cgroup is enabled && really_do_swap_account = 1 */
51 int do_swap_account __read_mostly;
52 static int really_do_swap_account __initdata = 1; /* for remember boot option*/
53 #else
54 #define do_swap_account         (0)
55 #endif
56
57 static DEFINE_MUTEX(memcg_tasklist);    /* can be hold under cgroup_mutex */
58 #define SOFTLIMIT_EVENTS_THRESH (1000)
59
60 /*
61  * Statistics for memory cgroup.
62  */
63 enum mem_cgroup_stat_index {
64         /*
65          * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss.
66          */
67         MEM_CGROUP_STAT_CACHE,     /* # of pages charged as cache */
68         MEM_CGROUP_STAT_RSS,       /* # of pages charged as anon rss */
69         MEM_CGROUP_STAT_MAPPED_FILE,  /* # of pages charged as file rss */
70         MEM_CGROUP_STAT_PGPGIN_COUNT,   /* # of pages paged in */
71         MEM_CGROUP_STAT_PGPGOUT_COUNT,  /* # of pages paged out */
72         MEM_CGROUP_STAT_EVENTS, /* sum of pagein + pageout for internal use */
73         MEM_CGROUP_STAT_SWAPOUT, /* # of pages, swapped out */
74
75         MEM_CGROUP_STAT_NSTATS,
76 };
77
78 struct mem_cgroup_stat_cpu {
79         s64 count[MEM_CGROUP_STAT_NSTATS];
80 } ____cacheline_aligned_in_smp;
81
82 struct mem_cgroup_stat {
83         struct mem_cgroup_stat_cpu cpustat[0];
84 };
85
86 static inline void
87 __mem_cgroup_stat_reset_safe(struct mem_cgroup_stat_cpu *stat,
88                                 enum mem_cgroup_stat_index idx)
89 {
90         stat->count[idx] = 0;
91 }
92
93 static inline s64
94 __mem_cgroup_stat_read_local(struct mem_cgroup_stat_cpu *stat,
95                                 enum mem_cgroup_stat_index idx)
96 {
97         return stat->count[idx];
98 }
99
100 /*
101  * For accounting under irq disable, no need for increment preempt count.
102  */
103 static inline void __mem_cgroup_stat_add_safe(struct mem_cgroup_stat_cpu *stat,
104                 enum mem_cgroup_stat_index idx, int val)
105 {
106         stat->count[idx] += val;
107 }
108
109 static s64 mem_cgroup_read_stat(struct mem_cgroup_stat *stat,
110                 enum mem_cgroup_stat_index idx)
111 {
112         int cpu;
113         s64 ret = 0;
114         for_each_possible_cpu(cpu)
115                 ret += stat->cpustat[cpu].count[idx];
116         return ret;
117 }
118
119 static s64 mem_cgroup_local_usage(struct mem_cgroup_stat *stat)
120 {
121         s64 ret;
122
123         ret = mem_cgroup_read_stat(stat, MEM_CGROUP_STAT_CACHE);
124         ret += mem_cgroup_read_stat(stat, MEM_CGROUP_STAT_RSS);
125         return ret;
126 }
127
128 /*
129  * per-zone information in memory controller.
130  */
131 struct mem_cgroup_per_zone {
132         /*
133          * spin_lock to protect the per cgroup LRU
134          */
135         struct list_head        lists[NR_LRU_LISTS];
136         unsigned long           count[NR_LRU_LISTS];
137
138         struct zone_reclaim_stat reclaim_stat;
139         struct rb_node          tree_node;      /* RB tree node */
140         unsigned long long      usage_in_excess;/* Set to the value by which */
141                                                 /* the soft limit is exceeded*/
142         bool                    on_tree;
143         struct mem_cgroup       *mem;           /* Back pointer, we cannot */
144                                                 /* use container_of        */
145 };
146 /* Macro for accessing counter */
147 #define MEM_CGROUP_ZSTAT(mz, idx)       ((mz)->count[(idx)])
148
149 struct mem_cgroup_per_node {
150         struct mem_cgroup_per_zone zoneinfo[MAX_NR_ZONES];
151 };
152
153 struct mem_cgroup_lru_info {
154         struct mem_cgroup_per_node *nodeinfo[MAX_NUMNODES];
155 };
156
157 /*
158  * Cgroups above their limits are maintained in a RB-Tree, independent of
159  * their hierarchy representation
160  */
161
162 struct mem_cgroup_tree_per_zone {
163         struct rb_root rb_root;
164         spinlock_t lock;
165 };
166
167 struct mem_cgroup_tree_per_node {
168         struct mem_cgroup_tree_per_zone rb_tree_per_zone[MAX_NR_ZONES];
169 };
170
171 struct mem_cgroup_tree {
172         struct mem_cgroup_tree_per_node *rb_tree_per_node[MAX_NUMNODES];
173 };
174
175 static struct mem_cgroup_tree soft_limit_tree __read_mostly;
176
177 /*
178  * The memory controller data structure. The memory controller controls both
179  * page cache and RSS per cgroup. We would eventually like to provide
180  * statistics based on the statistics developed by Rik Van Riel for clock-pro,
181  * to help the administrator determine what knobs to tune.
182  *
183  * TODO: Add a water mark for the memory controller. Reclaim will begin when
184  * we hit the water mark. May be even add a low water mark, such that
185  * no reclaim occurs from a cgroup at it's low water mark, this is
186  * a feature that will be implemented much later in the future.
187  */
188 struct mem_cgroup {
189         struct cgroup_subsys_state css;
190         /*
191          * the counter to account for memory usage
192          */
193         struct res_counter res;
194         /*
195          * the counter to account for mem+swap usage.
196          */
197         struct res_counter memsw;
198         /*
199          * Per cgroup active and inactive list, similar to the
200          * per zone LRU lists.
201          */
202         struct mem_cgroup_lru_info info;
203
204         /*
205           protect against reclaim related member.
206         */
207         spinlock_t reclaim_param_lock;
208
209         int     prev_priority;  /* for recording reclaim priority */
210
211         /*
212          * While reclaiming in a hiearchy, we cache the last child we
213          * reclaimed from.
214          */
215         int last_scanned_child;
216         /*
217          * Should the accounting and control be hierarchical, per subtree?
218          */
219         bool use_hierarchy;
220         unsigned long   last_oom_jiffies;
221         atomic_t        refcnt;
222
223         unsigned int    swappiness;
224
225         /* set when res.limit == memsw.limit */
226         bool            memsw_is_minimum;
227
228         /*
229          * statistics. This must be placed at the end of memcg.
230          */
231         struct mem_cgroup_stat stat;
232 };
233
234 /*
235  * Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft
236  * limit reclaim to prevent infinite loops, if they ever occur.
237  */
238 #define MEM_CGROUP_MAX_RECLAIM_LOOPS            (100)
239 #define MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS (2)
240
241 enum charge_type {
242         MEM_CGROUP_CHARGE_TYPE_CACHE = 0,
243         MEM_CGROUP_CHARGE_TYPE_MAPPED,
244         MEM_CGROUP_CHARGE_TYPE_SHMEM,   /* used by page migration of shmem */
245         MEM_CGROUP_CHARGE_TYPE_FORCE,   /* used by force_empty */
246         MEM_CGROUP_CHARGE_TYPE_SWAPOUT, /* for accounting swapcache */
247         MEM_CGROUP_CHARGE_TYPE_DROP,    /* a page was unused swap cache */
248         NR_CHARGE_TYPE,
249 };
250
251 /* only for here (for easy reading.) */
252 #define PCGF_CACHE      (1UL << PCG_CACHE)
253 #define PCGF_USED       (1UL << PCG_USED)
254 #define PCGF_LOCK       (1UL << PCG_LOCK)
255 /* Not used, but added here for completeness */
256 #define PCGF_ACCT       (1UL << PCG_ACCT)
257
258 /* for encoding cft->private value on file */
259 #define _MEM                    (0)
260 #define _MEMSWAP                (1)
261 #define MEMFILE_PRIVATE(x, val) (((x) << 16) | (val))
262 #define MEMFILE_TYPE(val)       (((val) >> 16) & 0xffff)
263 #define MEMFILE_ATTR(val)       ((val) & 0xffff)
264
265 /*
266  * Reclaim flags for mem_cgroup_hierarchical_reclaim
267  */
268 #define MEM_CGROUP_RECLAIM_NOSWAP_BIT   0x0
269 #define MEM_CGROUP_RECLAIM_NOSWAP       (1 << MEM_CGROUP_RECLAIM_NOSWAP_BIT)
270 #define MEM_CGROUP_RECLAIM_SHRINK_BIT   0x1
271 #define MEM_CGROUP_RECLAIM_SHRINK       (1 << MEM_CGROUP_RECLAIM_SHRINK_BIT)
272 #define MEM_CGROUP_RECLAIM_SOFT_BIT     0x2
273 #define MEM_CGROUP_RECLAIM_SOFT         (1 << MEM_CGROUP_RECLAIM_SOFT_BIT)
274
275 static void mem_cgroup_get(struct mem_cgroup *mem);
276 static void mem_cgroup_put(struct mem_cgroup *mem);
277 static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem);
278
279 static struct mem_cgroup_per_zone *
280 mem_cgroup_zoneinfo(struct mem_cgroup *mem, int nid, int zid)
281 {
282         return &mem->info.nodeinfo[nid]->zoneinfo[zid];
283 }
284
285 static struct mem_cgroup_per_zone *
286 page_cgroup_zoneinfo(struct page_cgroup *pc)
287 {
288         struct mem_cgroup *mem = pc->mem_cgroup;
289         int nid = page_cgroup_nid(pc);
290         int zid = page_cgroup_zid(pc);
291
292         if (!mem)
293                 return NULL;
294
295         return mem_cgroup_zoneinfo(mem, nid, zid);
296 }
297
298 static struct mem_cgroup_tree_per_zone *
299 soft_limit_tree_node_zone(int nid, int zid)
300 {
301         return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid];
302 }
303
304 static struct mem_cgroup_tree_per_zone *
305 soft_limit_tree_from_page(struct page *page)
306 {
307         int nid = page_to_nid(page);
308         int zid = page_zonenum(page);
309
310         return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid];
311 }
312
313 static void
314 __mem_cgroup_insert_exceeded(struct mem_cgroup *mem,
315                                 struct mem_cgroup_per_zone *mz,
316                                 struct mem_cgroup_tree_per_zone *mctz)
317 {
318         struct rb_node **p = &mctz->rb_root.rb_node;
319         struct rb_node *parent = NULL;
320         struct mem_cgroup_per_zone *mz_node;
321
322         if (mz->on_tree)
323                 return;
324
325         mz->usage_in_excess = res_counter_soft_limit_excess(&mem->res);
326         while (*p) {
327                 parent = *p;
328                 mz_node = rb_entry(parent, struct mem_cgroup_per_zone,
329                                         tree_node);
330                 if (mz->usage_in_excess < mz_node->usage_in_excess)
331                         p = &(*p)->rb_left;
332                 /*
333                  * We can't avoid mem cgroups that are over their soft
334                  * limit by the same amount
335                  */
336                 else if (mz->usage_in_excess >= mz_node->usage_in_excess)
337                         p = &(*p)->rb_right;
338         }
339         rb_link_node(&mz->tree_node, parent, p);
340         rb_insert_color(&mz->tree_node, &mctz->rb_root);
341         mz->on_tree = true;
342 }
343
344 static void
345 __mem_cgroup_remove_exceeded(struct mem_cgroup *mem,
346                                 struct mem_cgroup_per_zone *mz,
347                                 struct mem_cgroup_tree_per_zone *mctz)
348 {
349         if (!mz->on_tree)
350                 return;
351         rb_erase(&mz->tree_node, &mctz->rb_root);
352         mz->on_tree = false;
353 }
354
355 static void
356 mem_cgroup_remove_exceeded(struct mem_cgroup *mem,
357                                 struct mem_cgroup_per_zone *mz,
358                                 struct mem_cgroup_tree_per_zone *mctz)
359 {
360         spin_lock(&mctz->lock);
361         __mem_cgroup_remove_exceeded(mem, mz, mctz);
362         spin_unlock(&mctz->lock);
363 }
364
365 static bool mem_cgroup_soft_limit_check(struct mem_cgroup *mem)
366 {
367         bool ret = false;
368         int cpu;
369         s64 val;
370         struct mem_cgroup_stat_cpu *cpustat;
371
372         cpu = get_cpu();
373         cpustat = &mem->stat.cpustat[cpu];
374         val = __mem_cgroup_stat_read_local(cpustat, MEM_CGROUP_STAT_EVENTS);
375         if (unlikely(val > SOFTLIMIT_EVENTS_THRESH)) {
376                 __mem_cgroup_stat_reset_safe(cpustat, MEM_CGROUP_STAT_EVENTS);
377                 ret = true;
378         }
379         put_cpu();
380         return ret;
381 }
382
383 static void mem_cgroup_update_tree(struct mem_cgroup *mem, struct page *page)
384 {
385         unsigned long long new_usage_in_excess;
386         struct mem_cgroup_per_zone *mz;
387         struct mem_cgroup_tree_per_zone *mctz;
388         int nid = page_to_nid(page);
389         int zid = page_zonenum(page);
390         mctz = soft_limit_tree_from_page(page);
391
392         /*
393          * Necessary to update all ancestors when hierarchy is used.
394          * because their event counter is not touched.
395          */
396         for (; mem; mem = parent_mem_cgroup(mem)) {
397                 mz = mem_cgroup_zoneinfo(mem, nid, zid);
398                 new_usage_in_excess =
399                         res_counter_soft_limit_excess(&mem->res);
400                 /*
401                  * We have to update the tree if mz is on RB-tree or
402                  * mem is over its softlimit.
403                  */
404                 if (new_usage_in_excess || mz->on_tree) {
405                         spin_lock(&mctz->lock);
406                         /* if on-tree, remove it */
407                         if (mz->on_tree)
408                                 __mem_cgroup_remove_exceeded(mem, mz, mctz);
409                         /*
410                          * if over soft limit, insert again. mz->usage_in_excess
411                          * will be updated properly.
412                          */
413                         if (new_usage_in_excess)
414                                 __mem_cgroup_insert_exceeded(mem, mz, mctz);
415                         else
416                                 mz->usage_in_excess = 0;
417                         spin_unlock(&mctz->lock);
418                 }
419         }
420 }
421
422 static void mem_cgroup_remove_from_trees(struct mem_cgroup *mem)
423 {
424         int node, zone;
425         struct mem_cgroup_per_zone *mz;
426         struct mem_cgroup_tree_per_zone *mctz;
427
428         for_each_node_state(node, N_POSSIBLE) {
429                 for (zone = 0; zone < MAX_NR_ZONES; zone++) {
430                         mz = mem_cgroup_zoneinfo(mem, node, zone);
431                         mctz = soft_limit_tree_node_zone(node, zone);
432                         mem_cgroup_remove_exceeded(mem, mz, mctz);
433                 }
434         }
435 }
436
437 static inline unsigned long mem_cgroup_get_excess(struct mem_cgroup *mem)
438 {
439         return res_counter_soft_limit_excess(&mem->res) >> PAGE_SHIFT;
440 }
441
442 static struct mem_cgroup_per_zone *
443 __mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
444 {
445         struct rb_node *rightmost = NULL;
446         struct mem_cgroup_per_zone *mz;
447
448 retry:
449         mz = NULL;
450         rightmost = rb_last(&mctz->rb_root);
451         if (!rightmost)
452                 goto done;              /* Nothing to reclaim from */
453
454         mz = rb_entry(rightmost, struct mem_cgroup_per_zone, tree_node);
455         /*
456          * Remove the node now but someone else can add it back,
457          * we will to add it back at the end of reclaim to its correct
458          * position in the tree.
459          */
460         __mem_cgroup_remove_exceeded(mz->mem, mz, mctz);
461         if (!res_counter_soft_limit_excess(&mz->mem->res) ||
462                 !css_tryget(&mz->mem->css))
463                 goto retry;
464 done:
465         return mz;
466 }
467
468 static struct mem_cgroup_per_zone *
469 mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
470 {
471         struct mem_cgroup_per_zone *mz;
472
473         spin_lock(&mctz->lock);
474         mz = __mem_cgroup_largest_soft_limit_node(mctz);
475         spin_unlock(&mctz->lock);
476         return mz;
477 }
478
479 static void mem_cgroup_swap_statistics(struct mem_cgroup *mem,
480                                          bool charge)
481 {
482         int val = (charge) ? 1 : -1;
483         struct mem_cgroup_stat *stat = &mem->stat;
484         struct mem_cgroup_stat_cpu *cpustat;
485         int cpu = get_cpu();
486
487         cpustat = &stat->cpustat[cpu];
488         __mem_cgroup_stat_add_safe(cpustat, MEM_CGROUP_STAT_SWAPOUT, val);
489         put_cpu();
490 }
491
492 static void mem_cgroup_charge_statistics(struct mem_cgroup *mem,
493                                          struct page_cgroup *pc,
494                                          bool charge)
495 {
496         int val = (charge) ? 1 : -1;
497         struct mem_cgroup_stat *stat = &mem->stat;
498         struct mem_cgroup_stat_cpu *cpustat;
499         int cpu = get_cpu();
500
501         cpustat = &stat->cpustat[cpu];
502         if (PageCgroupCache(pc))
503                 __mem_cgroup_stat_add_safe(cpustat, MEM_CGROUP_STAT_CACHE, val);
504         else
505                 __mem_cgroup_stat_add_safe(cpustat, MEM_CGROUP_STAT_RSS, val);
506
507         if (charge)
508                 __mem_cgroup_stat_add_safe(cpustat,
509                                 MEM_CGROUP_STAT_PGPGIN_COUNT, 1);
510         else
511                 __mem_cgroup_stat_add_safe(cpustat,
512                                 MEM_CGROUP_STAT_PGPGOUT_COUNT, 1);
513         __mem_cgroup_stat_add_safe(cpustat, MEM_CGROUP_STAT_EVENTS, 1);
514         put_cpu();
515 }
516
517 static unsigned long mem_cgroup_get_local_zonestat(struct mem_cgroup *mem,
518                                         enum lru_list idx)
519 {
520         int nid, zid;
521         struct mem_cgroup_per_zone *mz;
522         u64 total = 0;
523
524         for_each_online_node(nid)
525                 for (zid = 0; zid < MAX_NR_ZONES; zid++) {
526                         mz = mem_cgroup_zoneinfo(mem, nid, zid);
527                         total += MEM_CGROUP_ZSTAT(mz, idx);
528                 }
529         return total;
530 }
531
532 static struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont)
533 {
534         return container_of(cgroup_subsys_state(cont,
535                                 mem_cgroup_subsys_id), struct mem_cgroup,
536                                 css);
537 }
538
539 struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
540 {
541         /*
542          * mm_update_next_owner() may clear mm->owner to NULL
543          * if it races with swapoff, page migration, etc.
544          * So this can be called with p == NULL.
545          */
546         if (unlikely(!p))
547                 return NULL;
548
549         return container_of(task_subsys_state(p, mem_cgroup_subsys_id),
550                                 struct mem_cgroup, css);
551 }
552
553 static struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm)
554 {
555         struct mem_cgroup *mem = NULL;
556
557         if (!mm)
558                 return NULL;
559         /*
560          * Because we have no locks, mm->owner's may be being moved to other
561          * cgroup. We use css_tryget() here even if this looks
562          * pessimistic (rather than adding locks here).
563          */
564         rcu_read_lock();
565         do {
566                 mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
567                 if (unlikely(!mem))
568                         break;
569         } while (!css_tryget(&mem->css));
570         rcu_read_unlock();
571         return mem;
572 }
573
574 /*
575  * Call callback function against all cgroup under hierarchy tree.
576  */
577 static int mem_cgroup_walk_tree(struct mem_cgroup *root, void *data,
578                           int (*func)(struct mem_cgroup *, void *))
579 {
580         int found, ret, nextid;
581         struct cgroup_subsys_state *css;
582         struct mem_cgroup *mem;
583
584         if (!root->use_hierarchy)
585                 return (*func)(root, data);
586
587         nextid = 1;
588         do {
589                 ret = 0;
590                 mem = NULL;
591
592                 rcu_read_lock();
593                 css = css_get_next(&mem_cgroup_subsys, nextid, &root->css,
594                                    &found);
595                 if (css && css_tryget(css))
596                         mem = container_of(css, struct mem_cgroup, css);
597                 rcu_read_unlock();
598
599                 if (mem) {
600                         ret = (*func)(mem, data);
601                         css_put(&mem->css);
602                 }
603                 nextid = found + 1;
604         } while (!ret && css);
605
606         return ret;
607 }
608
609 static inline bool mem_cgroup_is_root(struct mem_cgroup *mem)
610 {
611         return (mem == root_mem_cgroup);
612 }
613
614 /*
615  * Following LRU functions are allowed to be used without PCG_LOCK.
616  * Operations are called by routine of global LRU independently from memcg.
617  * What we have to take care of here is validness of pc->mem_cgroup.
618  *
619  * Changes to pc->mem_cgroup happens when
620  * 1. charge
621  * 2. moving account
622  * In typical case, "charge" is done before add-to-lru. Exception is SwapCache.
623  * It is added to LRU before charge.
624  * If PCG_USED bit is not set, page_cgroup is not added to this private LRU.
625  * When moving account, the page is not on LRU. It's isolated.
626  */
627
628 void mem_cgroup_del_lru_list(struct page *page, enum lru_list lru)
629 {
630         struct page_cgroup *pc;
631         struct mem_cgroup_per_zone *mz;
632
633         if (mem_cgroup_disabled())
634                 return;
635         pc = lookup_page_cgroup(page);
636         /* can happen while we handle swapcache. */
637         if (!TestClearPageCgroupAcctLRU(pc))
638                 return;
639         VM_BUG_ON(!pc->mem_cgroup);
640         /*
641          * We don't check PCG_USED bit. It's cleared when the "page" is finally
642          * removed from global LRU.
643          */
644         mz = page_cgroup_zoneinfo(pc);
645         MEM_CGROUP_ZSTAT(mz, lru) -= 1;
646         if (mem_cgroup_is_root(pc->mem_cgroup))
647                 return;
648         VM_BUG_ON(list_empty(&pc->lru));
649         list_del_init(&pc->lru);
650         return;
651 }
652
653 void mem_cgroup_del_lru(struct page *page)
654 {
655         mem_cgroup_del_lru_list(page, page_lru(page));
656 }
657
658 void mem_cgroup_rotate_lru_list(struct page *page, enum lru_list lru)
659 {
660         struct mem_cgroup_per_zone *mz;
661         struct page_cgroup *pc;
662
663         if (mem_cgroup_disabled())
664                 return;
665
666         pc = lookup_page_cgroup(page);
667         /*
668          * Used bit is set without atomic ops but after smp_wmb().
669          * For making pc->mem_cgroup visible, insert smp_rmb() here.
670          */
671         smp_rmb();
672         /* unused or root page is not rotated. */
673         if (!PageCgroupUsed(pc) || mem_cgroup_is_root(pc->mem_cgroup))
674                 return;
675         mz = page_cgroup_zoneinfo(pc);
676         list_move(&pc->lru, &mz->lists[lru]);
677 }
678
679 void mem_cgroup_add_lru_list(struct page *page, enum lru_list lru)
680 {
681         struct page_cgroup *pc;
682         struct mem_cgroup_per_zone *mz;
683
684         if (mem_cgroup_disabled())
685                 return;
686         pc = lookup_page_cgroup(page);
687         VM_BUG_ON(PageCgroupAcctLRU(pc));
688         /*
689          * Used bit is set without atomic ops but after smp_wmb().
690          * For making pc->mem_cgroup visible, insert smp_rmb() here.
691          */
692         smp_rmb();
693         if (!PageCgroupUsed(pc))
694                 return;
695
696         mz = page_cgroup_zoneinfo(pc);
697         MEM_CGROUP_ZSTAT(mz, lru) += 1;
698         SetPageCgroupAcctLRU(pc);
699         if (mem_cgroup_is_root(pc->mem_cgroup))
700                 return;
701         list_add(&pc->lru, &mz->lists[lru]);
702 }
703
704 /*
705  * At handling SwapCache, pc->mem_cgroup may be changed while it's linked to
706  * lru because the page may.be reused after it's fully uncharged (because of
707  * SwapCache behavior).To handle that, unlink page_cgroup from LRU when charge
708  * it again. This function is only used to charge SwapCache. It's done under
709  * lock_page and expected that zone->lru_lock is never held.
710  */
711 static void mem_cgroup_lru_del_before_commit_swapcache(struct page *page)
712 {
713         unsigned long flags;
714         struct zone *zone = page_zone(page);
715         struct page_cgroup *pc = lookup_page_cgroup(page);
716
717         spin_lock_irqsave(&zone->lru_lock, flags);
718         /*
719          * Forget old LRU when this page_cgroup is *not* used. This Used bit
720          * is guarded by lock_page() because the page is SwapCache.
721          */
722         if (!PageCgroupUsed(pc))
723                 mem_cgroup_del_lru_list(page, page_lru(page));
724         spin_unlock_irqrestore(&zone->lru_lock, flags);
725 }
726
727 static void mem_cgroup_lru_add_after_commit_swapcache(struct page *page)
728 {
729         unsigned long flags;
730         struct zone *zone = page_zone(page);
731         struct page_cgroup *pc = lookup_page_cgroup(page);
732
733         spin_lock_irqsave(&zone->lru_lock, flags);
734         /* link when the page is linked to LRU but page_cgroup isn't */
735         if (PageLRU(page) && !PageCgroupAcctLRU(pc))
736                 mem_cgroup_add_lru_list(page, page_lru(page));
737         spin_unlock_irqrestore(&zone->lru_lock, flags);
738 }
739
740
741 void mem_cgroup_move_lists(struct page *page,
742                            enum lru_list from, enum lru_list to)
743 {
744         if (mem_cgroup_disabled())
745                 return;
746         mem_cgroup_del_lru_list(page, from);
747         mem_cgroup_add_lru_list(page, to);
748 }
749
750 int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem)
751 {
752         int ret;
753         struct mem_cgroup *curr = NULL;
754
755         task_lock(task);
756         rcu_read_lock();
757         curr = try_get_mem_cgroup_from_mm(task->mm);
758         rcu_read_unlock();
759         task_unlock(task);
760         if (!curr)
761                 return 0;
762         if (curr->use_hierarchy)
763                 ret = css_is_ancestor(&curr->css, &mem->css);
764         else
765                 ret = (curr == mem);
766         css_put(&curr->css);
767         return ret;
768 }
769
770 /*
771  * prev_priority control...this will be used in memory reclaim path.
772  */
773 int mem_cgroup_get_reclaim_priority(struct mem_cgroup *mem)
774 {
775         int prev_priority;
776
777         spin_lock(&mem->reclaim_param_lock);
778         prev_priority = mem->prev_priority;
779         spin_unlock(&mem->reclaim_param_lock);
780
781         return prev_priority;
782 }
783
784 void mem_cgroup_note_reclaim_priority(struct mem_cgroup *mem, int priority)
785 {
786         spin_lock(&mem->reclaim_param_lock);
787         if (priority < mem->prev_priority)
788                 mem->prev_priority = priority;
789         spin_unlock(&mem->reclaim_param_lock);
790 }
791
792 void mem_cgroup_record_reclaim_priority(struct mem_cgroup *mem, int priority)
793 {
794         spin_lock(&mem->reclaim_param_lock);
795         mem->prev_priority = priority;
796         spin_unlock(&mem->reclaim_param_lock);
797 }
798
799 static int calc_inactive_ratio(struct mem_cgroup *memcg, unsigned long *present_pages)
800 {
801         unsigned long active;
802         unsigned long inactive;
803         unsigned long gb;
804         unsigned long inactive_ratio;
805
806         inactive = mem_cgroup_get_local_zonestat(memcg, LRU_INACTIVE_ANON);
807         active = mem_cgroup_get_local_zonestat(memcg, LRU_ACTIVE_ANON);
808
809         gb = (inactive + active) >> (30 - PAGE_SHIFT);
810         if (gb)
811                 inactive_ratio = int_sqrt(10 * gb);
812         else
813                 inactive_ratio = 1;
814
815         if (present_pages) {
816                 present_pages[0] = inactive;
817                 present_pages[1] = active;
818         }
819
820         return inactive_ratio;
821 }
822
823 int mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg)
824 {
825         unsigned long active;
826         unsigned long inactive;
827         unsigned long present_pages[2];
828         unsigned long inactive_ratio;
829
830         inactive_ratio = calc_inactive_ratio(memcg, present_pages);
831
832         inactive = present_pages[0];
833         active = present_pages[1];
834
835         if (inactive * inactive_ratio < active)
836                 return 1;
837
838         return 0;
839 }
840
841 int mem_cgroup_inactive_file_is_low(struct mem_cgroup *memcg)
842 {
843         unsigned long active;
844         unsigned long inactive;
845
846         inactive = mem_cgroup_get_local_zonestat(memcg, LRU_INACTIVE_FILE);
847         active = mem_cgroup_get_local_zonestat(memcg, LRU_ACTIVE_FILE);
848
849         return (active > inactive);
850 }
851
852 unsigned long mem_cgroup_zone_nr_pages(struct mem_cgroup *memcg,
853                                        struct zone *zone,
854                                        enum lru_list lru)
855 {
856         int nid = zone->zone_pgdat->node_id;
857         int zid = zone_idx(zone);
858         struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid);
859
860         return MEM_CGROUP_ZSTAT(mz, lru);
861 }
862
863 struct zone_reclaim_stat *mem_cgroup_get_reclaim_stat(struct mem_cgroup *memcg,
864                                                       struct zone *zone)
865 {
866         int nid = zone->zone_pgdat->node_id;
867         int zid = zone_idx(zone);
868         struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid);
869
870         return &mz->reclaim_stat;
871 }
872
873 struct zone_reclaim_stat *
874 mem_cgroup_get_reclaim_stat_from_page(struct page *page)
875 {
876         struct page_cgroup *pc;
877         struct mem_cgroup_per_zone *mz;
878
879         if (mem_cgroup_disabled())
880                 return NULL;
881
882         pc = lookup_page_cgroup(page);
883         /*
884          * Used bit is set without atomic ops but after smp_wmb().
885          * For making pc->mem_cgroup visible, insert smp_rmb() here.
886          */
887         smp_rmb();
888         if (!PageCgroupUsed(pc))
889                 return NULL;
890
891         mz = page_cgroup_zoneinfo(pc);
892         if (!mz)
893                 return NULL;
894
895         return &mz->reclaim_stat;
896 }
897
898 unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
899                                         struct list_head *dst,
900                                         unsigned long *scanned, int order,
901                                         int mode, struct zone *z,
902                                         struct mem_cgroup *mem_cont,
903                                         int active, int file)
904 {
905         unsigned long nr_taken = 0;
906         struct page *page;
907         unsigned long scan;
908         LIST_HEAD(pc_list);
909         struct list_head *src;
910         struct page_cgroup *pc, *tmp;
911         int nid = z->zone_pgdat->node_id;
912         int zid = zone_idx(z);
913         struct mem_cgroup_per_zone *mz;
914         int lru = LRU_FILE * file + active;
915         int ret;
916
917         BUG_ON(!mem_cont);
918         mz = mem_cgroup_zoneinfo(mem_cont, nid, zid);
919         src = &mz->lists[lru];
920
921         scan = 0;
922         list_for_each_entry_safe_reverse(pc, tmp, src, lru) {
923                 if (scan >= nr_to_scan)
924                         break;
925
926                 page = pc->page;
927                 if (unlikely(!PageCgroupUsed(pc)))
928                         continue;
929                 if (unlikely(!PageLRU(page)))
930                         continue;
931
932                 scan++;
933                 ret = __isolate_lru_page(page, mode, file);
934                 switch (ret) {
935                 case 0:
936                         list_move(&page->lru, dst);
937                         mem_cgroup_del_lru(page);
938                         nr_taken++;
939                         break;
940                 case -EBUSY:
941                         /* we don't affect global LRU but rotate in our LRU */
942                         mem_cgroup_rotate_lru_list(page, page_lru(page));
943                         break;
944                 default:
945                         break;
946                 }
947         }
948
949         *scanned = scan;
950         return nr_taken;
951 }
952
953 #define mem_cgroup_from_res_counter(counter, member)    \
954         container_of(counter, struct mem_cgroup, member)
955
956 static bool mem_cgroup_check_under_limit(struct mem_cgroup *mem)
957 {
958         if (do_swap_account) {
959                 if (res_counter_check_under_limit(&mem->res) &&
960                         res_counter_check_under_limit(&mem->memsw))
961                         return true;
962         } else
963                 if (res_counter_check_under_limit(&mem->res))
964                         return true;
965         return false;
966 }
967
968 static unsigned int get_swappiness(struct mem_cgroup *memcg)
969 {
970         struct cgroup *cgrp = memcg->css.cgroup;
971         unsigned int swappiness;
972
973         /* root ? */
974         if (cgrp->parent == NULL)
975                 return vm_swappiness;
976
977         spin_lock(&memcg->reclaim_param_lock);
978         swappiness = memcg->swappiness;
979         spin_unlock(&memcg->reclaim_param_lock);
980
981         return swappiness;
982 }
983
984 static int mem_cgroup_count_children_cb(struct mem_cgroup *mem, void *data)
985 {
986         int *val = data;
987         (*val)++;
988         return 0;
989 }
990
991 /**
992  * mem_cgroup_print_mem_info: Called from OOM with tasklist_lock held in read mode.
993  * @memcg: The memory cgroup that went over limit
994  * @p: Task that is going to be killed
995  *
996  * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is
997  * enabled
998  */
999 void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
1000 {
1001         struct cgroup *task_cgrp;
1002         struct cgroup *mem_cgrp;
1003         /*
1004          * Need a buffer in BSS, can't rely on allocations. The code relies
1005          * on the assumption that OOM is serialized for memory controller.
1006          * If this assumption is broken, revisit this code.
1007          */
1008         static char memcg_name[PATH_MAX];
1009         int ret;
1010
1011         if (!memcg)
1012                 return;
1013
1014
1015         rcu_read_lock();
1016
1017         mem_cgrp = memcg->css.cgroup;
1018         task_cgrp = task_cgroup(p, mem_cgroup_subsys_id);
1019
1020         ret = cgroup_path(task_cgrp, memcg_name, PATH_MAX);
1021         if (ret < 0) {
1022                 /*
1023                  * Unfortunately, we are unable to convert to a useful name
1024                  * But we'll still print out the usage information
1025                  */
1026                 rcu_read_unlock();
1027                 goto done;
1028         }
1029         rcu_read_unlock();
1030
1031         printk(KERN_INFO "Task in %s killed", memcg_name);
1032
1033         rcu_read_lock();
1034         ret = cgroup_path(mem_cgrp, memcg_name, PATH_MAX);
1035         if (ret < 0) {
1036                 rcu_read_unlock();
1037                 goto done;
1038         }
1039         rcu_read_unlock();
1040
1041         /*
1042          * Continues from above, so we don't need an KERN_ level
1043          */
1044         printk(KERN_CONT " as a result of limit of %s\n", memcg_name);
1045 done:
1046
1047         printk(KERN_INFO "memory: usage %llukB, limit %llukB, failcnt %llu\n",
1048                 res_counter_read_u64(&memcg->res, RES_USAGE) >> 10,
1049                 res_counter_read_u64(&memcg->res, RES_LIMIT) >> 10,
1050                 res_counter_read_u64(&memcg->res, RES_FAILCNT));
1051         printk(KERN_INFO "memory+swap: usage %llukB, limit %llukB, "
1052                 "failcnt %llu\n",
1053                 res_counter_read_u64(&memcg->memsw, RES_USAGE) >> 10,
1054                 res_counter_read_u64(&memcg->memsw, RES_LIMIT) >> 10,
1055                 res_counter_read_u64(&memcg->memsw, RES_FAILCNT));
1056 }
1057
1058 /*
1059  * This function returns the number of memcg under hierarchy tree. Returns
1060  * 1(self count) if no children.
1061  */
1062 static int mem_cgroup_count_children(struct mem_cgroup *mem)
1063 {
1064         int num = 0;
1065         mem_cgroup_walk_tree(mem, &num, mem_cgroup_count_children_cb);
1066         return num;
1067 }
1068
1069 /*
1070  * Visit the first child (need not be the first child as per the ordering
1071  * of the cgroup list, since we track last_scanned_child) of @mem and use
1072  * that to reclaim free pages from.
1073  */
1074 static struct mem_cgroup *
1075 mem_cgroup_select_victim(struct mem_cgroup *root_mem)
1076 {
1077         struct mem_cgroup *ret = NULL;
1078         struct cgroup_subsys_state *css;
1079         int nextid, found;
1080
1081         if (!root_mem->use_hierarchy) {
1082                 css_get(&root_mem->css);
1083                 ret = root_mem;
1084         }
1085
1086         while (!ret) {
1087                 rcu_read_lock();
1088                 nextid = root_mem->last_scanned_child + 1;
1089                 css = css_get_next(&mem_cgroup_subsys, nextid, &root_mem->css,
1090                                    &found);
1091                 if (css && css_tryget(css))
1092                         ret = container_of(css, struct mem_cgroup, css);
1093
1094                 rcu_read_unlock();
1095                 /* Updates scanning parameter */
1096                 spin_lock(&root_mem->reclaim_param_lock);
1097                 if (!css) {
1098                         /* this means start scan from ID:1 */
1099                         root_mem->last_scanned_child = 0;
1100                 } else
1101                         root_mem->last_scanned_child = found;
1102                 spin_unlock(&root_mem->reclaim_param_lock);
1103         }
1104
1105         return ret;
1106 }
1107
1108 /*
1109  * Scan the hierarchy if needed to reclaim memory. We remember the last child
1110  * we reclaimed from, so that we don't end up penalizing one child extensively
1111  * based on its position in the children list.
1112  *
1113  * root_mem is the original ancestor that we've been reclaim from.
1114  *
1115  * We give up and return to the caller when we visit root_mem twice.
1116  * (other groups can be removed while we're walking....)
1117  *
1118  * If shrink==true, for avoiding to free too much, this returns immedieately.
1119  */
1120 static int mem_cgroup_hierarchical_reclaim(struct mem_cgroup *root_mem,
1121                                                 struct zone *zone,
1122                                                 gfp_t gfp_mask,
1123                                                 unsigned long reclaim_options)
1124 {
1125         struct mem_cgroup *victim;
1126         int ret, total = 0;
1127         int loop = 0;
1128         bool noswap = reclaim_options & MEM_CGROUP_RECLAIM_NOSWAP;
1129         bool shrink = reclaim_options & MEM_CGROUP_RECLAIM_SHRINK;
1130         bool check_soft = reclaim_options & MEM_CGROUP_RECLAIM_SOFT;
1131         unsigned long excess = mem_cgroup_get_excess(root_mem);
1132
1133         /* If memsw_is_minimum==1, swap-out is of-no-use. */
1134         if (root_mem->memsw_is_minimum)
1135                 noswap = true;
1136
1137         while (1) {
1138                 victim = mem_cgroup_select_victim(root_mem);
1139                 if (victim == root_mem) {
1140                         loop++;
1141                         if (loop >= 2) {
1142                                 /*
1143                                  * If we have not been able to reclaim
1144                                  * anything, it might because there are
1145                                  * no reclaimable pages under this hierarchy
1146                                  */
1147                                 if (!check_soft || !total) {
1148                                         css_put(&victim->css);
1149                                         break;
1150                                 }
1151                                 /*
1152                                  * We want to do more targetted reclaim.
1153                                  * excess >> 2 is not to excessive so as to
1154                                  * reclaim too much, nor too less that we keep
1155                                  * coming back to reclaim from this cgroup
1156                                  */
1157                                 if (total >= (excess >> 2) ||
1158                                         (loop > MEM_CGROUP_MAX_RECLAIM_LOOPS)) {
1159                                         css_put(&victim->css);
1160                                         break;
1161                                 }
1162                         }
1163                 }
1164                 if (!mem_cgroup_local_usage(&victim->stat)) {
1165                         /* this cgroup's local usage == 0 */
1166                         css_put(&victim->css);
1167                         continue;
1168                 }
1169                 /* we use swappiness of local cgroup */
1170                 if (check_soft)
1171                         ret = mem_cgroup_shrink_node_zone(victim, gfp_mask,
1172                                 noswap, get_swappiness(victim), zone,
1173                                 zone->zone_pgdat->node_id);
1174                 else
1175                         ret = try_to_free_mem_cgroup_pages(victim, gfp_mask,
1176                                                 noswap, get_swappiness(victim));
1177                 css_put(&victim->css);
1178                 /*
1179                  * At shrinking usage, we can't check we should stop here or
1180                  * reclaim more. It's depends on callers. last_scanned_child
1181                  * will work enough for keeping fairness under tree.
1182                  */
1183                 if (shrink)
1184                         return ret;
1185                 total += ret;
1186                 if (check_soft) {
1187                         if (res_counter_check_under_soft_limit(&root_mem->res))
1188                                 return total;
1189                 } else if (mem_cgroup_check_under_limit(root_mem))
1190                         return 1 + total;
1191         }
1192         return total;
1193 }
1194
1195 bool mem_cgroup_oom_called(struct task_struct *task)
1196 {
1197         bool ret = false;
1198         struct mem_cgroup *mem;
1199         struct mm_struct *mm;
1200
1201         rcu_read_lock();
1202         mm = task->mm;
1203         if (!mm)
1204                 mm = &init_mm;
1205         mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
1206         if (mem && time_before(jiffies, mem->last_oom_jiffies + HZ/10))
1207                 ret = true;
1208         rcu_read_unlock();
1209         return ret;
1210 }
1211
1212 static int record_last_oom_cb(struct mem_cgroup *mem, void *data)
1213 {
1214         mem->last_oom_jiffies = jiffies;
1215         return 0;
1216 }
1217
1218 static void record_last_oom(struct mem_cgroup *mem)
1219 {
1220         mem_cgroup_walk_tree(mem, NULL, record_last_oom_cb);
1221 }
1222
1223 /*
1224  * Currently used to update mapped file statistics, but the routine can be
1225  * generalized to update other statistics as well.
1226  */
1227 void mem_cgroup_update_mapped_file_stat(struct page *page, int val)
1228 {
1229         struct mem_cgroup *mem;
1230         struct mem_cgroup_stat *stat;
1231         struct mem_cgroup_stat_cpu *cpustat;
1232         int cpu;
1233         struct page_cgroup *pc;
1234
1235         if (!page_is_file_cache(page))
1236                 return;
1237
1238         pc = lookup_page_cgroup(page);
1239         if (unlikely(!pc))
1240                 return;
1241
1242         lock_page_cgroup(pc);
1243         mem = pc->mem_cgroup;
1244         if (!mem)
1245                 goto done;
1246
1247         if (!PageCgroupUsed(pc))
1248                 goto done;
1249
1250         /*
1251          * Preemption is already disabled, we don't need get_cpu()
1252          */
1253         cpu = smp_processor_id();
1254         stat = &mem->stat;
1255         cpustat = &stat->cpustat[cpu];
1256
1257         __mem_cgroup_stat_add_safe(cpustat, MEM_CGROUP_STAT_MAPPED_FILE, val);
1258 done:
1259         unlock_page_cgroup(pc);
1260 }
1261
1262 /*
1263  * Unlike exported interface, "oom" parameter is added. if oom==true,
1264  * oom-killer can be invoked.
1265  */
1266 static int __mem_cgroup_try_charge(struct mm_struct *mm,
1267                         gfp_t gfp_mask, struct mem_cgroup **memcg,
1268                         bool oom, struct page *page)
1269 {
1270         struct mem_cgroup *mem, *mem_over_limit;
1271         int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
1272         struct res_counter *fail_res;
1273
1274         if (unlikely(test_thread_flag(TIF_MEMDIE))) {
1275                 /* Don't account this! */
1276                 *memcg = NULL;
1277                 return 0;
1278         }
1279
1280         /*
1281          * We always charge the cgroup the mm_struct belongs to.
1282          * The mm_struct's mem_cgroup changes on task migration if the
1283          * thread group leader migrates. It's possible that mm is not
1284          * set, if so charge the init_mm (happens for pagecache usage).
1285          */
1286         mem = *memcg;
1287         if (likely(!mem)) {
1288                 mem = try_get_mem_cgroup_from_mm(mm);
1289                 *memcg = mem;
1290         } else {
1291                 css_get(&mem->css);
1292         }
1293         if (unlikely(!mem))
1294                 return 0;
1295
1296         VM_BUG_ON(css_is_removed(&mem->css));
1297
1298         while (1) {
1299                 int ret = 0;
1300                 unsigned long flags = 0;
1301
1302                 if (mem_cgroup_is_root(mem))
1303                         goto done;
1304                 ret = res_counter_charge(&mem->res, PAGE_SIZE, &fail_res);
1305                 if (likely(!ret)) {
1306                         if (!do_swap_account)
1307                                 break;
1308                         ret = res_counter_charge(&mem->memsw, PAGE_SIZE,
1309                                                         &fail_res);
1310                         if (likely(!ret))
1311                                 break;
1312                         /* mem+swap counter fails */
1313                         res_counter_uncharge(&mem->res, PAGE_SIZE);
1314                         flags |= MEM_CGROUP_RECLAIM_NOSWAP;
1315                         mem_over_limit = mem_cgroup_from_res_counter(fail_res,
1316                                                                         memsw);
1317                 } else
1318                         /* mem counter fails */
1319                         mem_over_limit = mem_cgroup_from_res_counter(fail_res,
1320                                                                         res);
1321
1322                 if (!(gfp_mask & __GFP_WAIT))
1323                         goto nomem;
1324
1325                 ret = mem_cgroup_hierarchical_reclaim(mem_over_limit, NULL,
1326                                                 gfp_mask, flags);
1327                 if (ret)
1328                         continue;
1329
1330                 /*
1331                  * try_to_free_mem_cgroup_pages() might not give us a full
1332                  * picture of reclaim. Some pages are reclaimed and might be
1333                  * moved to swap cache or just unmapped from the cgroup.
1334                  * Check the limit again to see if the reclaim reduced the
1335                  * current usage of the cgroup before giving up
1336                  *
1337                  */
1338                 if (mem_cgroup_check_under_limit(mem_over_limit))
1339                         continue;
1340
1341                 if (!nr_retries--) {
1342                         if (oom) {
1343                                 mutex_lock(&memcg_tasklist);
1344                                 mem_cgroup_out_of_memory(mem_over_limit, gfp_mask);
1345                                 mutex_unlock(&memcg_tasklist);
1346                                 record_last_oom(mem_over_limit);
1347                         }
1348                         goto nomem;
1349                 }
1350         }
1351         /*
1352          * Insert ancestor (and ancestor's ancestors), to softlimit RB-tree.
1353          * if they exceeds softlimit.
1354          */
1355         if (mem_cgroup_soft_limit_check(mem))
1356                 mem_cgroup_update_tree(mem, page);
1357 done:
1358         return 0;
1359 nomem:
1360         css_put(&mem->css);
1361         return -ENOMEM;
1362 }
1363
1364 /*
1365  * A helper function to get mem_cgroup from ID. must be called under
1366  * rcu_read_lock(). The caller must check css_is_removed() or some if
1367  * it's concern. (dropping refcnt from swap can be called against removed
1368  * memcg.)
1369  */
1370 static struct mem_cgroup *mem_cgroup_lookup(unsigned short id)
1371 {
1372         struct cgroup_subsys_state *css;
1373
1374         /* ID 0 is unused ID */
1375         if (!id)
1376                 return NULL;
1377         css = css_lookup(&mem_cgroup_subsys, id);
1378         if (!css)
1379                 return NULL;
1380         return container_of(css, struct mem_cgroup, css);
1381 }
1382
1383 static struct mem_cgroup *try_get_mem_cgroup_from_swapcache(struct page *page)
1384 {
1385         struct mem_cgroup *mem;
1386         struct page_cgroup *pc;
1387         unsigned short id;
1388         swp_entry_t ent;
1389
1390         VM_BUG_ON(!PageLocked(page));
1391
1392         if (!PageSwapCache(page))
1393                 return NULL;
1394
1395         pc = lookup_page_cgroup(page);
1396         lock_page_cgroup(pc);
1397         if (PageCgroupUsed(pc)) {
1398                 mem = pc->mem_cgroup;
1399                 if (mem && !css_tryget(&mem->css))
1400                         mem = NULL;
1401         } else {
1402                 ent.val = page_private(page);
1403                 id = lookup_swap_cgroup(ent);
1404                 rcu_read_lock();
1405                 mem = mem_cgroup_lookup(id);
1406                 if (mem && !css_tryget(&mem->css))
1407                         mem = NULL;
1408                 rcu_read_unlock();
1409         }
1410         unlock_page_cgroup(pc);
1411         return mem;
1412 }
1413
1414 /*
1415  * commit a charge got by __mem_cgroup_try_charge() and makes page_cgroup to be
1416  * USED state. If already USED, uncharge and return.
1417  */
1418
1419 static void __mem_cgroup_commit_charge(struct mem_cgroup *mem,
1420                                      struct page_cgroup *pc,
1421                                      enum charge_type ctype)
1422 {
1423         /* try_charge() can return NULL to *memcg, taking care of it. */
1424         if (!mem)
1425                 return;
1426
1427         lock_page_cgroup(pc);
1428         if (unlikely(PageCgroupUsed(pc))) {
1429                 unlock_page_cgroup(pc);
1430                 if (!mem_cgroup_is_root(mem)) {
1431                         res_counter_uncharge(&mem->res, PAGE_SIZE);
1432                         if (do_swap_account)
1433                                 res_counter_uncharge(&mem->memsw, PAGE_SIZE);
1434                 }
1435                 css_put(&mem->css);
1436                 return;
1437         }
1438
1439         pc->mem_cgroup = mem;
1440         /*
1441          * We access a page_cgroup asynchronously without lock_page_cgroup().
1442          * Especially when a page_cgroup is taken from a page, pc->mem_cgroup
1443          * is accessed after testing USED bit. To make pc->mem_cgroup visible
1444          * before USED bit, we need memory barrier here.
1445          * See mem_cgroup_add_lru_list(), etc.
1446          */
1447         smp_wmb();
1448         switch (ctype) {
1449         case MEM_CGROUP_CHARGE_TYPE_CACHE:
1450         case MEM_CGROUP_CHARGE_TYPE_SHMEM:
1451                 SetPageCgroupCache(pc);
1452                 SetPageCgroupUsed(pc);
1453                 break;
1454         case MEM_CGROUP_CHARGE_TYPE_MAPPED:
1455                 ClearPageCgroupCache(pc);
1456                 SetPageCgroupUsed(pc);
1457                 break;
1458         default:
1459                 break;
1460         }
1461
1462         mem_cgroup_charge_statistics(mem, pc, true);
1463
1464         unlock_page_cgroup(pc);
1465 }
1466
1467 /**
1468  * mem_cgroup_move_account - move account of the page
1469  * @pc: page_cgroup of the page.
1470  * @from: mem_cgroup which the page is moved from.
1471  * @to: mem_cgroup which the page is moved to. @from != @to.
1472  *
1473  * The caller must confirm following.
1474  * - page is not on LRU (isolate_page() is useful.)
1475  *
1476  * returns 0 at success,
1477  * returns -EBUSY when lock is busy or "pc" is unstable.
1478  *
1479  * This function does "uncharge" from old cgroup but doesn't do "charge" to
1480  * new cgroup. It should be done by a caller.
1481  */
1482
1483 static int mem_cgroup_move_account(struct page_cgroup *pc,
1484         struct mem_cgroup *from, struct mem_cgroup *to)
1485 {
1486         struct mem_cgroup_per_zone *from_mz, *to_mz;
1487         int nid, zid;
1488         int ret = -EBUSY;
1489         struct page *page;
1490         int cpu;
1491         struct mem_cgroup_stat *stat;
1492         struct mem_cgroup_stat_cpu *cpustat;
1493
1494         VM_BUG_ON(from == to);
1495         VM_BUG_ON(PageLRU(pc->page));
1496
1497         nid = page_cgroup_nid(pc);
1498         zid = page_cgroup_zid(pc);
1499         from_mz =  mem_cgroup_zoneinfo(from, nid, zid);
1500         to_mz =  mem_cgroup_zoneinfo(to, nid, zid);
1501
1502         if (!trylock_page_cgroup(pc))
1503                 return ret;
1504
1505         if (!PageCgroupUsed(pc))
1506                 goto out;
1507
1508         if (pc->mem_cgroup != from)
1509                 goto out;
1510
1511         if (!mem_cgroup_is_root(from))
1512                 res_counter_uncharge(&from->res, PAGE_SIZE);
1513         mem_cgroup_charge_statistics(from, pc, false);
1514
1515         page = pc->page;
1516         if (page_is_file_cache(page) && page_mapped(page)) {
1517                 cpu = smp_processor_id();
1518                 /* Update mapped_file data for mem_cgroup "from" */
1519                 stat = &from->stat;
1520                 cpustat = &stat->cpustat[cpu];
1521                 __mem_cgroup_stat_add_safe(cpustat, MEM_CGROUP_STAT_MAPPED_FILE,
1522                                                 -1);
1523
1524                 /* Update mapped_file data for mem_cgroup "to" */
1525                 stat = &to->stat;
1526                 cpustat = &stat->cpustat[cpu];
1527                 __mem_cgroup_stat_add_safe(cpustat, MEM_CGROUP_STAT_MAPPED_FILE,
1528                                                 1);
1529         }
1530
1531         if (do_swap_account && !mem_cgroup_is_root(from))
1532                 res_counter_uncharge(&from->memsw, PAGE_SIZE);
1533         css_put(&from->css);
1534
1535         css_get(&to->css);
1536         pc->mem_cgroup = to;
1537         mem_cgroup_charge_statistics(to, pc, true);
1538         ret = 0;
1539 out:
1540         unlock_page_cgroup(pc);
1541         /*
1542          * We charges against "to" which may not have any tasks. Then, "to"
1543          * can be under rmdir(). But in current implementation, caller of
1544          * this function is just force_empty() and it's garanteed that
1545          * "to" is never removed. So, we don't check rmdir status here.
1546          */
1547         return ret;
1548 }
1549
1550 /*
1551  * move charges to its parent.
1552  */
1553
1554 static int mem_cgroup_move_parent(struct page_cgroup *pc,
1555                                   struct mem_cgroup *child,
1556                                   gfp_t gfp_mask)
1557 {
1558         struct page *page = pc->page;
1559         struct cgroup *cg = child->css.cgroup;
1560         struct cgroup *pcg = cg->parent;
1561         struct mem_cgroup *parent;
1562         int ret;
1563
1564         /* Is ROOT ? */
1565         if (!pcg)
1566                 return -EINVAL;
1567
1568
1569         parent = mem_cgroup_from_cont(pcg);
1570
1571
1572         ret = __mem_cgroup_try_charge(NULL, gfp_mask, &parent, false, page);
1573         if (ret || !parent)
1574                 return ret;
1575
1576         if (!get_page_unless_zero(page)) {
1577                 ret = -EBUSY;
1578                 goto uncharge;
1579         }
1580
1581         ret = isolate_lru_page(page);
1582
1583         if (ret)
1584                 goto cancel;
1585
1586         ret = mem_cgroup_move_account(pc, child, parent);
1587
1588         putback_lru_page(page);
1589         if (!ret) {
1590                 put_page(page);
1591                 /* drop extra refcnt by try_charge() */
1592                 css_put(&parent->css);
1593                 return 0;
1594         }
1595
1596 cancel:
1597         put_page(page);
1598 uncharge:
1599         /* drop extra refcnt by try_charge() */
1600         css_put(&parent->css);
1601         /* uncharge if move fails */
1602         if (!mem_cgroup_is_root(parent)) {
1603                 res_counter_uncharge(&parent->res, PAGE_SIZE);
1604                 if (do_swap_account)
1605                         res_counter_uncharge(&parent->memsw, PAGE_SIZE);
1606         }
1607         return ret;
1608 }
1609
1610 /*
1611  * Charge the memory controller for page usage.
1612  * Return
1613  * 0 if the charge was successful
1614  * < 0 if the cgroup is over its limit
1615  */
1616 static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm,
1617                                 gfp_t gfp_mask, enum charge_type ctype,
1618                                 struct mem_cgroup *memcg)
1619 {
1620         struct mem_cgroup *mem;
1621         struct page_cgroup *pc;
1622         int ret;
1623
1624         pc = lookup_page_cgroup(page);
1625         /* can happen at boot */
1626         if (unlikely(!pc))
1627                 return 0;
1628         prefetchw(pc);
1629
1630         mem = memcg;
1631         ret = __mem_cgroup_try_charge(mm, gfp_mask, &mem, true, page);
1632         if (ret || !mem)
1633                 return ret;
1634
1635         __mem_cgroup_commit_charge(mem, pc, ctype);
1636         return 0;
1637 }
1638
1639 int mem_cgroup_newpage_charge(struct page *page,
1640                               struct mm_struct *mm, gfp_t gfp_mask)
1641 {
1642         if (mem_cgroup_disabled())
1643                 return 0;
1644         if (PageCompound(page))
1645                 return 0;
1646         /*
1647          * If already mapped, we don't have to account.
1648          * If page cache, page->mapping has address_space.
1649          * But page->mapping may have out-of-use anon_vma pointer,
1650          * detecit it by PageAnon() check. newly-mapped-anon's page->mapping
1651          * is NULL.
1652          */
1653         if (page_mapped(page) || (page->mapping && !PageAnon(page)))
1654                 return 0;
1655         if (unlikely(!mm))
1656                 mm = &init_mm;
1657         return mem_cgroup_charge_common(page, mm, gfp_mask,
1658                                 MEM_CGROUP_CHARGE_TYPE_MAPPED, NULL);
1659 }
1660
1661 static void
1662 __mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr,
1663                                         enum charge_type ctype);
1664
1665 int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
1666                                 gfp_t gfp_mask)
1667 {
1668         struct mem_cgroup *mem = NULL;
1669         int ret;
1670
1671         if (mem_cgroup_disabled())
1672                 return 0;
1673         if (PageCompound(page))
1674                 return 0;
1675         /*
1676          * Corner case handling. This is called from add_to_page_cache()
1677          * in usual. But some FS (shmem) precharges this page before calling it
1678          * and call add_to_page_cache() with GFP_NOWAIT.
1679          *
1680          * For GFP_NOWAIT case, the page may be pre-charged before calling
1681          * add_to_page_cache(). (See shmem.c) check it here and avoid to call
1682          * charge twice. (It works but has to pay a bit larger cost.)
1683          * And when the page is SwapCache, it should take swap information
1684          * into account. This is under lock_page() now.
1685          */
1686         if (!(gfp_mask & __GFP_WAIT)) {
1687                 struct page_cgroup *pc;
1688
1689
1690                 pc = lookup_page_cgroup(page);
1691                 if (!pc)
1692                         return 0;
1693                 lock_page_cgroup(pc);
1694                 if (PageCgroupUsed(pc)) {
1695                         unlock_page_cgroup(pc);
1696                         return 0;
1697                 }
1698                 unlock_page_cgroup(pc);
1699         }
1700
1701         if (unlikely(!mm && !mem))
1702                 mm = &init_mm;
1703
1704         if (page_is_file_cache(page))
1705                 return mem_cgroup_charge_common(page, mm, gfp_mask,
1706                                 MEM_CGROUP_CHARGE_TYPE_CACHE, NULL);
1707
1708         /* shmem */
1709         if (PageSwapCache(page)) {
1710                 ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &mem);
1711                 if (!ret)
1712                         __mem_cgroup_commit_charge_swapin(page, mem,
1713                                         MEM_CGROUP_CHARGE_TYPE_SHMEM);
1714         } else
1715                 ret = mem_cgroup_charge_common(page, mm, gfp_mask,
1716                                         MEM_CGROUP_CHARGE_TYPE_SHMEM, mem);
1717
1718         return ret;
1719 }
1720
1721 /*
1722  * While swap-in, try_charge -> commit or cancel, the page is locked.
1723  * And when try_charge() successfully returns, one refcnt to memcg without
1724  * struct page_cgroup is aquired. This refcnt will be cumsumed by
1725  * "commit()" or removed by "cancel()"
1726  */
1727 int mem_cgroup_try_charge_swapin(struct mm_struct *mm,
1728                                  struct page *page,
1729                                  gfp_t mask, struct mem_cgroup **ptr)
1730 {
1731         struct mem_cgroup *mem;
1732         int ret;
1733
1734         if (mem_cgroup_disabled())
1735                 return 0;
1736
1737         if (!do_swap_account)
1738                 goto charge_cur_mm;
1739         /*
1740          * A racing thread's fault, or swapoff, may have already updated
1741          * the pte, and even removed page from swap cache: return success
1742          * to go on to do_swap_page()'s pte_same() test, which should fail.
1743          */
1744         if (!PageSwapCache(page))
1745                 return 0;
1746         mem = try_get_mem_cgroup_from_swapcache(page);
1747         if (!mem)
1748                 goto charge_cur_mm;
1749         *ptr = mem;
1750         ret = __mem_cgroup_try_charge(NULL, mask, ptr, true, page);
1751         /* drop extra refcnt from tryget */
1752         css_put(&mem->css);
1753         return ret;
1754 charge_cur_mm:
1755         if (unlikely(!mm))
1756                 mm = &init_mm;
1757         return __mem_cgroup_try_charge(mm, mask, ptr, true, page);
1758 }
1759
1760 static void
1761 __mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr,
1762                                         enum charge_type ctype)
1763 {
1764         struct page_cgroup *pc;
1765
1766         if (mem_cgroup_disabled())
1767                 return;
1768         if (!ptr)
1769                 return;
1770         cgroup_exclude_rmdir(&ptr->css);
1771         pc = lookup_page_cgroup(page);
1772         mem_cgroup_lru_del_before_commit_swapcache(page);
1773         __mem_cgroup_commit_charge(ptr, pc, ctype);
1774         mem_cgroup_lru_add_after_commit_swapcache(page);
1775         /*
1776          * Now swap is on-memory. This means this page may be
1777          * counted both as mem and swap....double count.
1778          * Fix it by uncharging from memsw. Basically, this SwapCache is stable
1779          * under lock_page(). But in do_swap_page()::memory.c, reuse_swap_page()
1780          * may call delete_from_swap_cache() before reach here.
1781          */
1782         if (do_swap_account && PageSwapCache(page)) {
1783                 swp_entry_t ent = {.val = page_private(page)};
1784                 unsigned short id;
1785                 struct mem_cgroup *memcg;
1786
1787                 id = swap_cgroup_record(ent, 0);
1788                 rcu_read_lock();
1789                 memcg = mem_cgroup_lookup(id);
1790                 if (memcg) {
1791                         /*
1792                          * This recorded memcg can be obsolete one. So, avoid
1793                          * calling css_tryget
1794                          */
1795                         if (!mem_cgroup_is_root(memcg))
1796                                 res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
1797                         mem_cgroup_swap_statistics(memcg, false);
1798                         mem_cgroup_put(memcg);
1799                 }
1800                 rcu_read_unlock();
1801         }
1802         /*
1803          * At swapin, we may charge account against cgroup which has no tasks.
1804          * So, rmdir()->pre_destroy() can be called while we do this charge.
1805          * In that case, we need to call pre_destroy() again. check it here.
1806          */
1807         cgroup_release_and_wakeup_rmdir(&ptr->css);
1808 }
1809
1810 void mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr)
1811 {
1812         __mem_cgroup_commit_charge_swapin(page, ptr,
1813                                         MEM_CGROUP_CHARGE_TYPE_MAPPED);
1814 }
1815
1816 void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *mem)
1817 {
1818         if (mem_cgroup_disabled())
1819                 return;
1820         if (!mem)
1821                 return;
1822         if (!mem_cgroup_is_root(mem)) {
1823                 res_counter_uncharge(&mem->res, PAGE_SIZE);
1824                 if (do_swap_account)
1825                         res_counter_uncharge(&mem->memsw, PAGE_SIZE);
1826         }
1827         css_put(&mem->css);
1828 }
1829
1830
1831 /*
1832  * uncharge if !page_mapped(page)
1833  */
1834 static struct mem_cgroup *
1835 __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
1836 {
1837         struct page_cgroup *pc;
1838         struct mem_cgroup *mem = NULL;
1839         struct mem_cgroup_per_zone *mz;
1840
1841         if (mem_cgroup_disabled())
1842                 return NULL;
1843
1844         if (PageSwapCache(page))
1845                 return NULL;
1846
1847         /*
1848          * Check if our page_cgroup is valid
1849          */
1850         pc = lookup_page_cgroup(page);
1851         if (unlikely(!pc || !PageCgroupUsed(pc)))
1852                 return NULL;
1853
1854         lock_page_cgroup(pc);
1855
1856         mem = pc->mem_cgroup;
1857
1858         if (!PageCgroupUsed(pc))
1859                 goto unlock_out;
1860
1861         switch (ctype) {
1862         case MEM_CGROUP_CHARGE_TYPE_MAPPED:
1863         case MEM_CGROUP_CHARGE_TYPE_DROP:
1864                 if (page_mapped(page))
1865                         goto unlock_out;
1866                 break;
1867         case MEM_CGROUP_CHARGE_TYPE_SWAPOUT:
1868                 if (!PageAnon(page)) {  /* Shared memory */
1869                         if (page->mapping && !page_is_file_cache(page))
1870                                 goto unlock_out;
1871                 } else if (page_mapped(page)) /* Anon */
1872                                 goto unlock_out;
1873                 break;
1874         default:
1875                 break;
1876         }
1877
1878         if (!mem_cgroup_is_root(mem)) {
1879                 res_counter_uncharge(&mem->res, PAGE_SIZE);
1880                 if (do_swap_account &&
1881                                 (ctype != MEM_CGROUP_CHARGE_TYPE_SWAPOUT))
1882                         res_counter_uncharge(&mem->memsw, PAGE_SIZE);
1883         }
1884         if (ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT)
1885                 mem_cgroup_swap_statistics(mem, true);
1886         mem_cgroup_charge_statistics(mem, pc, false);
1887
1888         ClearPageCgroupUsed(pc);
1889         /*
1890          * pc->mem_cgroup is not cleared here. It will be accessed when it's
1891          * freed from LRU. This is safe because uncharged page is expected not
1892          * to be reused (freed soon). Exception is SwapCache, it's handled by
1893          * special functions.
1894          */
1895
1896         mz = page_cgroup_zoneinfo(pc);
1897         unlock_page_cgroup(pc);
1898
1899         if (mem_cgroup_soft_limit_check(mem))
1900                 mem_cgroup_update_tree(mem, page);
1901         /* at swapout, this memcg will be accessed to record to swap */
1902         if (ctype != MEM_CGROUP_CHARGE_TYPE_SWAPOUT)
1903                 css_put(&mem->css);
1904
1905         return mem;
1906
1907 unlock_out:
1908         unlock_page_cgroup(pc);
1909         return NULL;
1910 }
1911
1912 void mem_cgroup_uncharge_page(struct page *page)
1913 {
1914         /* early check. */
1915         if (page_mapped(page))
1916                 return;
1917         if (page->mapping && !PageAnon(page))
1918                 return;
1919         __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_MAPPED);
1920 }
1921
1922 void mem_cgroup_uncharge_cache_page(struct page *page)
1923 {
1924         VM_BUG_ON(page_mapped(page));
1925         VM_BUG_ON(page->mapping);
1926         __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE);
1927 }
1928
1929 #ifdef CONFIG_SWAP
1930 /*
1931  * called after __delete_from_swap_cache() and drop "page" account.
1932  * memcg information is recorded to swap_cgroup of "ent"
1933  */
1934 void
1935 mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout)
1936 {
1937         struct mem_cgroup *memcg;
1938         int ctype = MEM_CGROUP_CHARGE_TYPE_SWAPOUT;
1939
1940         if (!swapout) /* this was a swap cache but the swap is unused ! */
1941                 ctype = MEM_CGROUP_CHARGE_TYPE_DROP;
1942
1943         memcg = __mem_cgroup_uncharge_common(page, ctype);
1944
1945         /* record memcg information */
1946         if (do_swap_account && swapout && memcg) {
1947                 swap_cgroup_record(ent, css_id(&memcg->css));
1948                 mem_cgroup_get(memcg);
1949         }
1950         if (swapout && memcg)
1951                 css_put(&memcg->css);
1952 }
1953 #endif
1954
1955 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
1956 /*
1957  * called from swap_entry_free(). remove record in swap_cgroup and
1958  * uncharge "memsw" account.
1959  */
1960 void mem_cgroup_uncharge_swap(swp_entry_t ent)
1961 {
1962         struct mem_cgroup *memcg;
1963         unsigned short id;
1964
1965         if (!do_swap_account)
1966                 return;
1967
1968         id = swap_cgroup_record(ent, 0);
1969         rcu_read_lock();
1970         memcg = mem_cgroup_lookup(id);
1971         if (memcg) {
1972                 /*
1973                  * We uncharge this because swap is freed.
1974                  * This memcg can be obsolete one. We avoid calling css_tryget
1975                  */
1976                 if (!mem_cgroup_is_root(memcg))
1977                         res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
1978                 mem_cgroup_swap_statistics(memcg, false);
1979                 mem_cgroup_put(memcg);
1980         }
1981         rcu_read_unlock();
1982 }
1983 #endif
1984
1985 /*
1986  * Before starting migration, account PAGE_SIZE to mem_cgroup that the old
1987  * page belongs to.
1988  */
1989 int mem_cgroup_prepare_migration(struct page *page, struct mem_cgroup **ptr)
1990 {
1991         struct page_cgroup *pc;
1992         struct mem_cgroup *mem = NULL;
1993         int ret = 0;
1994
1995         if (mem_cgroup_disabled())
1996                 return 0;
1997
1998         pc = lookup_page_cgroup(page);
1999         lock_page_cgroup(pc);
2000         if (PageCgroupUsed(pc)) {
2001                 mem = pc->mem_cgroup;
2002                 css_get(&mem->css);
2003         }
2004         unlock_page_cgroup(pc);
2005
2006         if (mem) {
2007                 ret = __mem_cgroup_try_charge(NULL, GFP_KERNEL, &mem, false,
2008                                                 page);
2009                 css_put(&mem->css);
2010         }
2011         *ptr = mem;
2012         return ret;
2013 }
2014
2015 /* remove redundant charge if migration failed*/
2016 void mem_cgroup_end_migration(struct mem_cgroup *mem,
2017                 struct page *oldpage, struct page *newpage)
2018 {
2019         struct page *target, *unused;
2020         struct page_cgroup *pc;
2021         enum charge_type ctype;
2022
2023         if (!mem)
2024                 return;
2025         cgroup_exclude_rmdir(&mem->css);
2026         /* at migration success, oldpage->mapping is NULL. */
2027         if (oldpage->mapping) {
2028                 target = oldpage;
2029                 unused = NULL;
2030         } else {
2031                 target = newpage;
2032                 unused = oldpage;
2033         }
2034
2035         if (PageAnon(target))
2036                 ctype = MEM_CGROUP_CHARGE_TYPE_MAPPED;
2037         else if (page_is_file_cache(target))
2038                 ctype = MEM_CGROUP_CHARGE_TYPE_CACHE;
2039         else
2040                 ctype = MEM_CGROUP_CHARGE_TYPE_SHMEM;
2041
2042         /* unused page is not on radix-tree now. */
2043         if (unused)
2044                 __mem_cgroup_uncharge_common(unused, ctype);
2045
2046         pc = lookup_page_cgroup(target);
2047         /*
2048          * __mem_cgroup_commit_charge() check PCG_USED bit of page_cgroup.
2049          * So, double-counting is effectively avoided.
2050          */
2051         __mem_cgroup_commit_charge(mem, pc, ctype);
2052
2053         /*
2054          * Both of oldpage and newpage are still under lock_page().
2055          * Then, we don't have to care about race in radix-tree.
2056          * But we have to be careful that this page is unmapped or not.
2057          *
2058          * There is a case for !page_mapped(). At the start of
2059          * migration, oldpage was mapped. But now, it's zapped.
2060          * But we know *target* page is not freed/reused under us.
2061          * mem_cgroup_uncharge_page() does all necessary checks.
2062          */
2063         if (ctype == MEM_CGROUP_CHARGE_TYPE_MAPPED)
2064                 mem_cgroup_uncharge_page(target);
2065         /*
2066          * At migration, we may charge account against cgroup which has no tasks
2067          * So, rmdir()->pre_destroy() can be called while we do this charge.
2068          * In that case, we need to call pre_destroy() again. check it here.
2069          */
2070         cgroup_release_and_wakeup_rmdir(&mem->css);
2071 }
2072
2073 /*
2074  * A call to try to shrink memory usage on charge failure at shmem's swapin.
2075  * Calling hierarchical_reclaim is not enough because we should update
2076  * last_oom_jiffies to prevent pagefault_out_of_memory from invoking global OOM.
2077  * Moreover considering hierarchy, we should reclaim from the mem_over_limit,
2078  * not from the memcg which this page would be charged to.
2079  * try_charge_swapin does all of these works properly.
2080  */
2081 int mem_cgroup_shmem_charge_fallback(struct page *page,
2082                             struct mm_struct *mm,
2083                             gfp_t gfp_mask)
2084 {
2085         struct mem_cgroup *mem = NULL;
2086         int ret;
2087
2088         if (mem_cgroup_disabled())
2089                 return 0;
2090
2091         ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &mem);
2092         if (!ret)
2093                 mem_cgroup_cancel_charge_swapin(mem); /* it does !mem check */
2094
2095         return ret;
2096 }
2097
2098 static DEFINE_MUTEX(set_limit_mutex);
2099
2100 static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
2101                                 unsigned long long val)
2102 {
2103         int retry_count;
2104         int progress;
2105         u64 memswlimit;
2106         int ret = 0;
2107         int children = mem_cgroup_count_children(memcg);
2108         u64 curusage, oldusage;
2109
2110         /*
2111          * For keeping hierarchical_reclaim simple, how long we should retry
2112          * is depends on callers. We set our retry-count to be function
2113          * of # of children which we should visit in this loop.
2114          */
2115         retry_count = MEM_CGROUP_RECLAIM_RETRIES * children;
2116
2117         oldusage = res_counter_read_u64(&memcg->res, RES_USAGE);
2118
2119         while (retry_count) {
2120                 if (signal_pending(current)) {
2121                         ret = -EINTR;
2122                         break;
2123                 }
2124                 /*
2125                  * Rather than hide all in some function, I do this in
2126                  * open coded manner. You see what this really does.
2127                  * We have to guarantee mem->res.limit < mem->memsw.limit.
2128                  */
2129                 mutex_lock(&set_limit_mutex);
2130                 memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
2131                 if (memswlimit < val) {
2132                         ret = -EINVAL;
2133                         mutex_unlock(&set_limit_mutex);
2134                         break;
2135                 }
2136                 ret = res_counter_set_limit(&memcg->res, val);
2137                 if (!ret) {
2138                         if (memswlimit == val)
2139                                 memcg->memsw_is_minimum = true;
2140                         else
2141                                 memcg->memsw_is_minimum = false;
2142                 }
2143                 mutex_unlock(&set_limit_mutex);
2144
2145                 if (!ret)
2146                         break;
2147
2148                 progress = mem_cgroup_hierarchical_reclaim(memcg, NULL,
2149                                                 GFP_KERNEL,
2150                                                 MEM_CGROUP_RECLAIM_SHRINK);
2151                 curusage = res_counter_read_u64(&memcg->res, RES_USAGE);
2152                 /* Usage is reduced ? */
2153                 if (curusage >= oldusage)
2154                         retry_count--;
2155                 else
2156                         oldusage = curusage;
2157         }
2158
2159         return ret;
2160 }
2161
2162 static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
2163                                         unsigned long long val)
2164 {
2165         int retry_count;
2166         u64 memlimit, oldusage, curusage;
2167         int children = mem_cgroup_count_children(memcg);
2168         int ret = -EBUSY;
2169
2170         /* see mem_cgroup_resize_res_limit */
2171         retry_count = children * MEM_CGROUP_RECLAIM_RETRIES;
2172         oldusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
2173         while (retry_count) {
2174                 if (signal_pending(current)) {
2175                         ret = -EINTR;
2176                         break;
2177                 }
2178                 /*
2179                  * Rather than hide all in some function, I do this in
2180                  * open coded manner. You see what this really does.
2181                  * We have to guarantee mem->res.limit < mem->memsw.limit.
2182                  */
2183                 mutex_lock(&set_limit_mutex);
2184                 memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT);
2185                 if (memlimit > val) {
2186                         ret = -EINVAL;
2187                         mutex_unlock(&set_limit_mutex);
2188                         break;
2189                 }
2190                 ret = res_counter_set_limit(&memcg->memsw, val);
2191                 if (!ret) {
2192                         if (memlimit == val)
2193                                 memcg->memsw_is_minimum = true;
2194                         else
2195                                 memcg->memsw_is_minimum = false;
2196                 }
2197                 mutex_unlock(&set_limit_mutex);
2198
2199                 if (!ret)
2200                         break;
2201
2202                 mem_cgroup_hierarchical_reclaim(memcg, NULL, GFP_KERNEL,
2203                                                 MEM_CGROUP_RECLAIM_NOSWAP |
2204                                                 MEM_CGROUP_RECLAIM_SHRINK);
2205                 curusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
2206                 /* Usage is reduced ? */
2207                 if (curusage >= oldusage)
2208                         retry_count--;
2209                 else
2210                         oldusage = curusage;
2211         }
2212         return ret;
2213 }
2214
2215 unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
2216                                                 gfp_t gfp_mask, int nid,
2217                                                 int zid)
2218 {
2219         unsigned long nr_reclaimed = 0;
2220         struct mem_cgroup_per_zone *mz, *next_mz = NULL;
2221         unsigned long reclaimed;
2222         int loop = 0;
2223         struct mem_cgroup_tree_per_zone *mctz;
2224
2225         if (order > 0)
2226                 return 0;
2227
2228         mctz = soft_limit_tree_node_zone(nid, zid);
2229         /*
2230          * This loop can run a while, specially if mem_cgroup's continuously
2231          * keep exceeding their soft limit and putting the system under
2232          * pressure
2233          */
2234         do {
2235                 if (next_mz)
2236                         mz = next_mz;
2237                 else
2238                         mz = mem_cgroup_largest_soft_limit_node(mctz);
2239                 if (!mz)
2240                         break;
2241
2242                 reclaimed = mem_cgroup_hierarchical_reclaim(mz->mem, zone,
2243                                                 gfp_mask,
2244                                                 MEM_CGROUP_RECLAIM_SOFT);
2245                 nr_reclaimed += reclaimed;
2246                 spin_lock(&mctz->lock);
2247
2248                 /*
2249                  * If we failed to reclaim anything from this memory cgroup
2250                  * it is time to move on to the next cgroup
2251                  */
2252                 next_mz = NULL;
2253                 if (!reclaimed) {
2254                         do {
2255                                 /*
2256                                  * Loop until we find yet another one.
2257                                  *
2258                                  * By the time we get the soft_limit lock
2259                                  * again, someone might have aded the
2260                                  * group back on the RB tree. Iterate to
2261                                  * make sure we get a different mem.
2262                                  * mem_cgroup_largest_soft_limit_node returns
2263                                  * NULL if no other cgroup is present on
2264                                  * the tree
2265                                  */
2266                                 next_mz =
2267                                 __mem_cgroup_largest_soft_limit_node(mctz);
2268                                 if (next_mz == mz) {
2269                                         css_put(&next_mz->mem->css);
2270                                         next_mz = NULL;
2271                                 } else /* next_mz == NULL or other memcg */
2272                                         break;
2273                         } while (1);
2274                 }
2275                 mz->usage_in_excess =
2276                         res_counter_soft_limit_excess(&mz->mem->res);
2277                 __mem_cgroup_remove_exceeded(mz->mem, mz, mctz);
2278                 /*
2279                  * One school of thought says that we should not add
2280                  * back the node to the tree if reclaim returns 0.
2281                  * But our reclaim could return 0, simply because due
2282                  * to priority we are exposing a smaller subset of
2283                  * memory to reclaim from. Consider this as a longer
2284                  * term TODO.
2285                  */
2286                 if (mz->usage_in_excess)
2287                         __mem_cgroup_insert_exceeded(mz->mem, mz, mctz);
2288                 spin_unlock(&mctz->lock);
2289                 css_put(&mz->mem->css);
2290                 loop++;
2291                 /*
2292                  * Could not reclaim anything and there are no more
2293                  * mem cgroups to try or we seem to be looping without
2294                  * reclaiming anything.
2295                  */
2296                 if (!nr_reclaimed &&
2297                         (next_mz == NULL ||
2298                         loop > MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS))
2299                         break;
2300         } while (!nr_reclaimed);
2301         if (next_mz)
2302                 css_put(&next_mz->mem->css);
2303         return nr_reclaimed;
2304 }
2305
2306 /*
2307  * This routine traverse page_cgroup in given list and drop them all.
2308  * *And* this routine doesn't reclaim page itself, just removes page_cgroup.
2309  */
2310 static int mem_cgroup_force_empty_list(struct mem_cgroup *mem,
2311                                 int node, int zid, enum lru_list lru)
2312 {
2313         struct zone *zone;
2314         struct mem_cgroup_per_zone *mz;
2315         struct page_cgroup *pc, *busy;
2316         unsigned long flags, loop;
2317         struct list_head *list;
2318         int ret = 0;
2319
2320         zone = &NODE_DATA(node)->node_zones[zid];
2321         mz = mem_cgroup_zoneinfo(mem, node, zid);
2322         list = &mz->lists[lru];
2323
2324         loop = MEM_CGROUP_ZSTAT(mz, lru);
2325         /* give some margin against EBUSY etc...*/
2326         loop += 256;
2327         busy = NULL;
2328         while (loop--) {
2329                 ret = 0;
2330                 spin_lock_irqsave(&zone->lru_lock, flags);
2331                 if (list_empty(list)) {
2332                         spin_unlock_irqrestore(&zone->lru_lock, flags);
2333                         break;
2334                 }
2335                 pc = list_entry(list->prev, struct page_cgroup, lru);
2336                 if (busy == pc) {
2337                         list_move(&pc->lru, list);
2338                         busy = 0;
2339                         spin_unlock_irqrestore(&zone->lru_lock, flags);
2340                         continue;
2341                 }
2342                 spin_unlock_irqrestore(&zone->lru_lock, flags);
2343
2344                 ret = mem_cgroup_move_parent(pc, mem, GFP_KERNEL);
2345                 if (ret == -ENOMEM)
2346                         break;
2347
2348                 if (ret == -EBUSY || ret == -EINVAL) {
2349                         /* found lock contention or "pc" is obsolete. */
2350                         busy = pc;
2351                         cond_resched();
2352                 } else
2353                         busy = NULL;
2354         }
2355
2356         if (!ret && !list_empty(list))
2357                 return -EBUSY;
2358         return ret;
2359 }
2360
2361 /*
2362  * make mem_cgroup's charge to be 0 if there is no task.
2363  * This enables deleting this mem_cgroup.
2364  */
2365 static int mem_cgroup_force_empty(struct mem_cgroup *mem, bool free_all)
2366 {
2367         int ret;
2368         int node, zid, shrink;
2369         int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
2370         struct cgroup *cgrp = mem->css.cgroup;
2371
2372         css_get(&mem->css);
2373
2374         shrink = 0;
2375         /* should free all ? */
2376         if (free_all)
2377                 goto try_to_free;
2378 move_account:
2379         while (mem->res.usage > 0) {
2380                 ret = -EBUSY;
2381                 if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children))
2382                         goto out;
2383                 ret = -EINTR;
2384                 if (signal_pending(current))
2385                         goto out;
2386                 /* This is for making all *used* pages to be on LRU. */
2387                 lru_add_drain_all();
2388                 ret = 0;
2389                 for_each_node_state(node, N_HIGH_MEMORY) {
2390                         for (zid = 0; !ret && zid < MAX_NR_ZONES; zid++) {
2391                                 enum lru_list l;
2392                                 for_each_lru(l) {
2393                                         ret = mem_cgroup_force_empty_list(mem,
2394                                                         node, zid, l);
2395                                         if (ret)
2396                                                 break;
2397                                 }
2398                         }
2399                         if (ret)
2400                                 break;
2401                 }
2402                 /* it seems parent cgroup doesn't have enough mem */
2403                 if (ret == -ENOMEM)
2404                         goto try_to_free;
2405                 cond_resched();
2406         }
2407         ret = 0;
2408 out:
2409         css_put(&mem->css);
2410         return ret;
2411
2412 try_to_free:
2413         /* returns EBUSY if there is a task or if we come here twice. */
2414         if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children) || shrink) {
2415                 ret = -EBUSY;
2416                 goto out;
2417         }
2418         /* we call try-to-free pages for make this cgroup empty */
2419         lru_add_drain_all();
2420         /* try to free all pages in this cgroup */
2421         shrink = 1;
2422         while (nr_retries && mem->res.usage > 0) {
2423                 int progress;
2424
2425                 if (signal_pending(current)) {
2426                         ret = -EINTR;
2427                         goto out;
2428                 }
2429                 progress = try_to_free_mem_cgroup_pages(mem, GFP_KERNEL,
2430                                                 false, get_swappiness(mem));
2431                 if (!progress) {
2432                         nr_retries--;
2433                         /* maybe some writeback is necessary */
2434                         congestion_wait(BLK_RW_ASYNC, HZ/10);
2435                 }
2436
2437         }
2438         lru_add_drain();
2439         /* try move_account...there may be some *locked* pages. */
2440         if (mem->res.usage)
2441                 goto move_account;
2442         ret = 0;
2443         goto out;
2444 }
2445
2446 int mem_cgroup_force_empty_write(struct cgroup *cont, unsigned int event)
2447 {
2448         return mem_cgroup_force_empty(mem_cgroup_from_cont(cont), true);
2449 }
2450
2451
2452 static u64 mem_cgroup_hierarchy_read(struct cgroup *cont, struct cftype *cft)
2453 {
2454         return mem_cgroup_from_cont(cont)->use_hierarchy;
2455 }
2456
2457 static int mem_cgroup_hierarchy_write(struct cgroup *cont, struct cftype *cft,
2458                                         u64 val)
2459 {
2460         int retval = 0;
2461         struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
2462         struct cgroup *parent = cont->parent;
2463         struct mem_cgroup *parent_mem = NULL;
2464
2465         if (parent)
2466                 parent_mem = mem_cgroup_from_cont(parent);
2467
2468         cgroup_lock();
2469         /*
2470          * If parent's use_hiearchy is set, we can't make any modifications
2471          * in the child subtrees. If it is unset, then the change can
2472          * occur, provided the current cgroup has no children.
2473          *
2474          * For the root cgroup, parent_mem is NULL, we allow value to be
2475          * set if there are no children.
2476          */
2477         if ((!parent_mem || !parent_mem->use_hierarchy) &&
2478                                 (val == 1 || val == 0)) {
2479                 if (list_empty(&cont->children))
2480                         mem->use_hierarchy = val;
2481                 else
2482                         retval = -EBUSY;
2483         } else
2484                 retval = -EINVAL;
2485         cgroup_unlock();
2486
2487         return retval;
2488 }
2489
2490 struct mem_cgroup_idx_data {
2491         s64 val;
2492         enum mem_cgroup_stat_index idx;
2493 };
2494
2495 static int
2496 mem_cgroup_get_idx_stat(struct mem_cgroup *mem, void *data)
2497 {
2498         struct mem_cgroup_idx_data *d = data;
2499         d->val += mem_cgroup_read_stat(&mem->stat, d->idx);
2500         return 0;
2501 }
2502
2503 static void
2504 mem_cgroup_get_recursive_idx_stat(struct mem_cgroup *mem,
2505                                 enum mem_cgroup_stat_index idx, s64 *val)
2506 {
2507         struct mem_cgroup_idx_data d;
2508         d.idx = idx;
2509         d.val = 0;
2510         mem_cgroup_walk_tree(mem, &d, mem_cgroup_get_idx_stat);
2511         *val = d.val;
2512 }
2513
2514 static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft)
2515 {
2516         struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
2517         u64 idx_val, val;
2518         int type, name;
2519
2520         type = MEMFILE_TYPE(cft->private);
2521         name = MEMFILE_ATTR(cft->private);
2522         switch (type) {
2523         case _MEM:
2524                 if (name == RES_USAGE && mem_cgroup_is_root(mem)) {
2525                         mem_cgroup_get_recursive_idx_stat(mem,
2526                                 MEM_CGROUP_STAT_CACHE, &idx_val);
2527                         val = idx_val;
2528                         mem_cgroup_get_recursive_idx_stat(mem,
2529                                 MEM_CGROUP_STAT_RSS, &idx_val);
2530                         val += idx_val;
2531                         val <<= PAGE_SHIFT;
2532                 } else
2533                         val = res_counter_read_u64(&mem->res, name);
2534                 break;
2535         case _MEMSWAP:
2536                 if (name == RES_USAGE && mem_cgroup_is_root(mem)) {
2537                         mem_cgroup_get_recursive_idx_stat(mem,
2538                                 MEM_CGROUP_STAT_CACHE, &idx_val);
2539                         val = idx_val;
2540                         mem_cgroup_get_recursive_idx_stat(mem,
2541                                 MEM_CGROUP_STAT_RSS, &idx_val);
2542                         val += idx_val;
2543                         mem_cgroup_get_recursive_idx_stat(mem,
2544                                 MEM_CGROUP_STAT_SWAPOUT, &idx_val);
2545                         val <<= PAGE_SHIFT;
2546                 } else
2547                         val = res_counter_read_u64(&mem->memsw, name);
2548                 break;
2549         default:
2550                 BUG();
2551                 break;
2552         }
2553         return val;
2554 }
2555 /*
2556  * The user of this function is...
2557  * RES_LIMIT.
2558  */
2559 static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
2560                             const char *buffer)
2561 {
2562         struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
2563         int type, name;
2564         unsigned long long val;
2565         int ret;
2566
2567         type = MEMFILE_TYPE(cft->private);
2568         name = MEMFILE_ATTR(cft->private);
2569         switch (name) {
2570         case RES_LIMIT:
2571                 if (mem_cgroup_is_root(memcg)) { /* Can't set limit on root */
2572                         ret = -EINVAL;
2573                         break;
2574                 }
2575                 /* This function does all necessary parse...reuse it */
2576                 ret = res_counter_memparse_write_strategy(buffer, &val);
2577                 if (ret)
2578                         break;
2579                 if (type == _MEM)
2580                         ret = mem_cgroup_resize_limit(memcg, val);
2581                 else
2582                         ret = mem_cgroup_resize_memsw_limit(memcg, val);
2583                 break;
2584         case RES_SOFT_LIMIT:
2585                 ret = res_counter_memparse_write_strategy(buffer, &val);
2586                 if (ret)
2587                         break;
2588                 /*
2589                  * For memsw, soft limits are hard to implement in terms
2590                  * of semantics, for now, we support soft limits for
2591                  * control without swap
2592                  */
2593                 if (type == _MEM)
2594                         ret = res_counter_set_soft_limit(&memcg->res, val);
2595                 else
2596                         ret = -EINVAL;
2597                 break;
2598         default:
2599                 ret = -EINVAL; /* should be BUG() ? */
2600                 break;
2601         }
2602         return ret;
2603 }
2604
2605 static void memcg_get_hierarchical_limit(struct mem_cgroup *memcg,
2606                 unsigned long long *mem_limit, unsigned long long *memsw_limit)
2607 {
2608         struct cgroup *cgroup;
2609         unsigned long long min_limit, min_memsw_limit, tmp;
2610
2611         min_limit = res_counter_read_u64(&memcg->res, RES_LIMIT);
2612         min_memsw_limit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
2613         cgroup = memcg->css.cgroup;
2614         if (!memcg->use_hierarchy)
2615                 goto out;
2616
2617         while (cgroup->parent) {
2618                 cgroup = cgroup->parent;
2619                 memcg = mem_cgroup_from_cont(cgroup);
2620                 if (!memcg->use_hierarchy)
2621                         break;
2622                 tmp = res_counter_read_u64(&memcg->res, RES_LIMIT);
2623                 min_limit = min(min_limit, tmp);
2624                 tmp = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
2625                 min_memsw_limit = min(min_memsw_limit, tmp);
2626         }
2627 out:
2628         *mem_limit = min_limit;
2629         *memsw_limit = min_memsw_limit;
2630         return;
2631 }
2632
2633 static int mem_cgroup_reset(struct cgroup *cont, unsigned int event)
2634 {
2635         struct mem_cgroup *mem;
2636         int type, name;
2637
2638         mem = mem_cgroup_from_cont(cont);
2639         type = MEMFILE_TYPE(event);
2640         name = MEMFILE_ATTR(event);
2641         switch (name) {
2642         case RES_MAX_USAGE:
2643                 if (type == _MEM)
2644                         res_counter_reset_max(&mem->res);
2645                 else
2646                         res_counter_reset_max(&mem->memsw);
2647                 break;
2648         case RES_FAILCNT:
2649                 if (type == _MEM)
2650                         res_counter_reset_failcnt(&mem->res);
2651                 else
2652                         res_counter_reset_failcnt(&mem->memsw);
2653                 break;
2654         }
2655
2656         return 0;
2657 }
2658
2659
2660 /* For read statistics */
2661 enum {
2662         MCS_CACHE,
2663         MCS_RSS,
2664         MCS_MAPPED_FILE,
2665         MCS_PGPGIN,
2666         MCS_PGPGOUT,
2667         MCS_SWAP,
2668         MCS_INACTIVE_ANON,
2669         MCS_ACTIVE_ANON,
2670         MCS_INACTIVE_FILE,
2671         MCS_ACTIVE_FILE,
2672         MCS_UNEVICTABLE,
2673         NR_MCS_STAT,
2674 };
2675
2676 struct mcs_total_stat {
2677         s64 stat[NR_MCS_STAT];
2678 };
2679
2680 struct {
2681         char *local_name;
2682         char *total_name;
2683 } memcg_stat_strings[NR_MCS_STAT] = {
2684         {"cache", "total_cache"},
2685         {"rss", "total_rss"},
2686         {"mapped_file", "total_mapped_file"},
2687         {"pgpgin", "total_pgpgin"},
2688         {"pgpgout", "total_pgpgout"},
2689         {"swap", "total_swap"},
2690         {"inactive_anon", "total_inactive_anon"},
2691         {"active_anon", "total_active_anon"},
2692         {"inactive_file", "total_inactive_file"},
2693         {"active_file", "total_active_file"},
2694         {"unevictable", "total_unevictable"}
2695 };
2696
2697
2698 static int mem_cgroup_get_local_stat(struct mem_cgroup *mem, void *data)
2699 {
2700         struct mcs_total_stat *s = data;
2701         s64 val;
2702
2703         /* per cpu stat */
2704         val = mem_cgroup_read_stat(&mem->stat, MEM_CGROUP_STAT_CACHE);
2705         s->stat[MCS_CACHE] += val * PAGE_SIZE;
2706         val = mem_cgroup_read_stat(&mem->stat, MEM_CGROUP_STAT_RSS);
2707         s->stat[MCS_RSS] += val * PAGE_SIZE;
2708         val = mem_cgroup_read_stat(&mem->stat, MEM_CGROUP_STAT_MAPPED_FILE);
2709         s->stat[MCS_MAPPED_FILE] += val * PAGE_SIZE;
2710         val = mem_cgroup_read_stat(&mem->stat, MEM_CGROUP_STAT_PGPGIN_COUNT);
2711         s->stat[MCS_PGPGIN] += val;
2712         val = mem_cgroup_read_stat(&mem->stat, MEM_CGROUP_STAT_PGPGOUT_COUNT);
2713         s->stat[MCS_PGPGOUT] += val;
2714         if (do_swap_account) {
2715                 val = mem_cgroup_read_stat(&mem->stat, MEM_CGROUP_STAT_SWAPOUT);
2716                 s->stat[MCS_SWAP] += val * PAGE_SIZE;
2717         }
2718
2719         /* per zone stat */
2720         val = mem_cgroup_get_local_zonestat(mem, LRU_INACTIVE_ANON);
2721         s->stat[MCS_INACTIVE_ANON] += val * PAGE_SIZE;
2722         val = mem_cgroup_get_local_zonestat(mem, LRU_ACTIVE_ANON);
2723         s->stat[MCS_ACTIVE_ANON] += val * PAGE_SIZE;
2724         val = mem_cgroup_get_local_zonestat(mem, LRU_INACTIVE_FILE);
2725         s->stat[MCS_INACTIVE_FILE] += val * PAGE_SIZE;
2726         val = mem_cgroup_get_local_zonestat(mem, LRU_ACTIVE_FILE);
2727         s->stat[MCS_ACTIVE_FILE] += val * PAGE_SIZE;
2728         val = mem_cgroup_get_local_zonestat(mem, LRU_UNEVICTABLE);
2729         s->stat[MCS_UNEVICTABLE] += val * PAGE_SIZE;
2730         return 0;
2731 }
2732
2733 static void
2734 mem_cgroup_get_total_stat(struct mem_cgroup *mem, struct mcs_total_stat *s)
2735 {
2736         mem_cgroup_walk_tree(mem, s, mem_cgroup_get_local_stat);
2737 }
2738
2739 static int mem_control_stat_show(struct cgroup *cont, struct cftype *cft,
2740                                  struct cgroup_map_cb *cb)
2741 {
2742         struct mem_cgroup *mem_cont = mem_cgroup_from_cont(cont);
2743         struct mcs_total_stat mystat;
2744         int i;
2745
2746         memset(&mystat, 0, sizeof(mystat));
2747         mem_cgroup_get_local_stat(mem_cont, &mystat);
2748
2749         for (i = 0; i < NR_MCS_STAT; i++) {
2750                 if (i == MCS_SWAP && !do_swap_account)
2751                         continue;
2752                 cb->fill(cb, memcg_stat_strings[i].local_name, mystat.stat[i]);
2753         }
2754
2755         /* Hierarchical information */
2756         {
2757                 unsigned long long limit, memsw_limit;
2758                 memcg_get_hierarchical_limit(mem_cont, &limit, &memsw_limit);
2759                 cb->fill(cb, "hierarchical_memory_limit", limit);
2760                 if (do_swap_account)
2761                         cb->fill(cb, "hierarchical_memsw_limit", memsw_limit);
2762         }
2763
2764         memset(&mystat, 0, sizeof(mystat));
2765         mem_cgroup_get_total_stat(mem_cont, &mystat);
2766         for (i = 0; i < NR_MCS_STAT; i++) {
2767                 if (i == MCS_SWAP && !do_swap_account)
2768                         continue;
2769                 cb->fill(cb, memcg_stat_strings[i].total_name, mystat.stat[i]);
2770         }
2771
2772 #ifdef CONFIG_DEBUG_VM
2773         cb->fill(cb, "inactive_ratio", calc_inactive_ratio(mem_cont, NULL));
2774
2775         {
2776                 int nid, zid;
2777                 struct mem_cgroup_per_zone *mz;
2778                 unsigned long recent_rotated[2] = {0, 0};
2779                 unsigned long recent_scanned[2] = {0, 0};
2780
2781                 for_each_online_node(nid)
2782                         for (zid = 0; zid < MAX_NR_ZONES; zid++) {
2783                                 mz = mem_cgroup_zoneinfo(mem_cont, nid, zid);
2784
2785                                 recent_rotated[0] +=
2786                                         mz->reclaim_stat.recent_rotated[0];
2787                                 recent_rotated[1] +=
2788                                         mz->reclaim_stat.recent_rotated[1];
2789                                 recent_scanned[0] +=
2790                                         mz->reclaim_stat.recent_scanned[0];
2791                                 recent_scanned[1] +=
2792                                         mz->reclaim_stat.recent_scanned[1];
2793                         }
2794                 cb->fill(cb, "recent_rotated_anon", recent_rotated[0]);
2795                 cb->fill(cb, "recent_rotated_file", recent_rotated[1]);
2796                 cb->fill(cb, "recent_scanned_anon", recent_scanned[0]);
2797                 cb->fill(cb, "recent_scanned_file", recent_scanned[1]);
2798         }
2799 #endif
2800
2801         return 0;
2802 }
2803
2804 static u64 mem_cgroup_swappiness_read(struct cgroup *cgrp, struct cftype *cft)
2805 {
2806         struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
2807
2808         return get_swappiness(memcg);
2809 }
2810
2811 static int mem_cgroup_swappiness_write(struct cgroup *cgrp, struct cftype *cft,
2812                                        u64 val)
2813 {
2814         struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
2815         struct mem_cgroup *parent;
2816
2817         if (val > 100)
2818                 return -EINVAL;
2819
2820         if (cgrp->parent == NULL)
2821                 return -EINVAL;
2822
2823         parent = mem_cgroup_from_cont(cgrp->parent);
2824
2825         cgroup_lock();
2826
2827         /* If under hierarchy, only empty-root can set this value */
2828         if ((parent->use_hierarchy) ||
2829             (memcg->use_hierarchy && !list_empty(&cgrp->children))) {
2830                 cgroup_unlock();
2831                 return -EINVAL;
2832         }
2833
2834         spin_lock(&memcg->reclaim_param_lock);
2835         memcg->swappiness = val;
2836         spin_unlock(&memcg->reclaim_param_lock);
2837
2838         cgroup_unlock();
2839
2840         return 0;
2841 }
2842
2843
2844 static struct cftype mem_cgroup_files[] = {
2845         {
2846                 .name = "usage_in_bytes",
2847                 .private = MEMFILE_PRIVATE(_MEM, RES_USAGE),
2848                 .read_u64 = mem_cgroup_read,
2849         },
2850         {
2851                 .name = "max_usage_in_bytes",
2852                 .private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE),
2853                 .trigger = mem_cgroup_reset,
2854                 .read_u64 = mem_cgroup_read,
2855         },
2856         {
2857                 .name = "limit_in_bytes",
2858                 .private = MEMFILE_PRIVATE(_MEM, RES_LIMIT),
2859                 .write_string = mem_cgroup_write,
2860                 .read_u64 = mem_cgroup_read,
2861         },
2862         {
2863                 .name = "soft_limit_in_bytes",
2864                 .private = MEMFILE_PRIVATE(_MEM, RES_SOFT_LIMIT),
2865                 .write_string = mem_cgroup_write,
2866                 .read_u64 = mem_cgroup_read,
2867         },
2868         {
2869                 .name = "failcnt",
2870                 .private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT),
2871                 .trigger = mem_cgroup_reset,
2872                 .read_u64 = mem_cgroup_read,
2873         },
2874         {
2875                 .name = "stat",
2876                 .read_map = mem_control_stat_show,
2877         },
2878         {
2879                 .name = "force_empty",
2880                 .trigger = mem_cgroup_force_empty_write,
2881         },
2882         {
2883                 .name = "use_hierarchy",
2884                 .write_u64 = mem_cgroup_hierarchy_write,
2885                 .read_u64 = mem_cgroup_hierarchy_read,
2886         },
2887         {
2888                 .name = "swappiness",
2889                 .read_u64 = mem_cgroup_swappiness_read,
2890                 .write_u64 = mem_cgroup_swappiness_write,
2891         },
2892 };
2893
2894 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
2895 static struct cftype memsw_cgroup_files[] = {
2896         {
2897                 .name = "memsw.usage_in_bytes",
2898                 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE),
2899                 .read_u64 = mem_cgroup_read,
2900         },
2901         {
2902                 .name = "memsw.max_usage_in_bytes",
2903                 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE),
2904                 .trigger = mem_cgroup_reset,
2905                 .read_u64 = mem_cgroup_read,
2906         },
2907         {
2908                 .name = "memsw.limit_in_bytes",
2909                 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT),
2910                 .write_string = mem_cgroup_write,
2911                 .read_u64 = mem_cgroup_read,
2912         },
2913         {
2914                 .name = "memsw.failcnt",
2915                 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT),
2916                 .trigger = mem_cgroup_reset,
2917                 .read_u64 = mem_cgroup_read,
2918         },
2919 };
2920
2921 static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss)
2922 {
2923         if (!do_swap_account)
2924                 return 0;
2925         return cgroup_add_files(cont, ss, memsw_cgroup_files,
2926                                 ARRAY_SIZE(memsw_cgroup_files));
2927 };
2928 #else
2929 static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss)
2930 {
2931         return 0;
2932 }
2933 #endif
2934
2935 static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
2936 {
2937         struct mem_cgroup_per_node *pn;
2938         struct mem_cgroup_per_zone *mz;
2939         enum lru_list l;
2940         int zone, tmp = node;
2941         /*
2942          * This routine is called against possible nodes.
2943          * But it's BUG to call kmalloc() against offline node.
2944          *
2945          * TODO: this routine can waste much memory for nodes which will
2946          *       never be onlined. It's better to use memory hotplug callback
2947          *       function.
2948          */
2949         if (!node_state(node, N_NORMAL_MEMORY))
2950                 tmp = -1;
2951         pn = kmalloc_node(sizeof(*pn), GFP_KERNEL, tmp);
2952         if (!pn)
2953                 return 1;
2954
2955         mem->info.nodeinfo[node] = pn;
2956         memset(pn, 0, sizeof(*pn));
2957
2958         for (zone = 0; zone < MAX_NR_ZONES; zone++) {
2959                 mz = &pn->zoneinfo[zone];
2960                 for_each_lru(l)
2961                         INIT_LIST_HEAD(&mz->lists[l]);
2962                 mz->usage_in_excess = 0;
2963                 mz->on_tree = false;
2964                 mz->mem = mem;
2965         }
2966         return 0;
2967 }
2968
2969 static void free_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
2970 {
2971         kfree(mem->info.nodeinfo[node]);
2972 }
2973
2974 static int mem_cgroup_size(void)
2975 {
2976         int cpustat_size = nr_cpu_ids * sizeof(struct mem_cgroup_stat_cpu);
2977         return sizeof(struct mem_cgroup) + cpustat_size;
2978 }
2979
2980 static struct mem_cgroup *mem_cgroup_alloc(void)
2981 {
2982         struct mem_cgroup *mem;
2983         int size = mem_cgroup_size();
2984
2985         if (size < PAGE_SIZE)
2986                 mem = kmalloc(size, GFP_KERNEL);
2987         else
2988                 mem = vmalloc(size);
2989
2990         if (mem)
2991                 memset(mem, 0, size);
2992         return mem;
2993 }
2994
2995 /*
2996  * At destroying mem_cgroup, references from swap_cgroup can remain.
2997  * (scanning all at force_empty is too costly...)
2998  *
2999  * Instead of clearing all references at force_empty, we remember
3000  * the number of reference from swap_cgroup and free mem_cgroup when
3001  * it goes down to 0.
3002  *
3003  * Removal of cgroup itself succeeds regardless of refs from swap.
3004  */
3005
3006 static void __mem_cgroup_free(struct mem_cgroup *mem)
3007 {
3008         int node;
3009
3010         mem_cgroup_remove_from_trees(mem);
3011         free_css_id(&mem_cgroup_subsys, &mem->css);
3012
3013         for_each_node_state(node, N_POSSIBLE)
3014                 free_mem_cgroup_per_zone_info(mem, node);
3015
3016         if (mem_cgroup_size() < PAGE_SIZE)
3017                 kfree(mem);
3018         else
3019                 vfree(mem);
3020 }
3021
3022 static void mem_cgroup_get(struct mem_cgroup *mem)
3023 {
3024         atomic_inc(&mem->refcnt);
3025 }
3026
3027 static void mem_cgroup_put(struct mem_cgroup *mem)
3028 {
3029         if (atomic_dec_and_test(&mem->refcnt)) {
3030                 struct mem_cgroup *parent = parent_mem_cgroup(mem);
3031                 __mem_cgroup_free(mem);
3032                 if (parent)
3033                         mem_cgroup_put(parent);
3034         }
3035 }
3036
3037 /*
3038  * Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled.
3039  */
3040 static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem)
3041 {
3042         if (!mem->res.parent)
3043                 return NULL;
3044         return mem_cgroup_from_res_counter(mem->res.parent, res);
3045 }
3046
3047 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
3048 static void __init enable_swap_cgroup(void)
3049 {
3050         if (!mem_cgroup_disabled() && really_do_swap_account)
3051                 do_swap_account = 1;
3052 }
3053 #else
3054 static void __init enable_swap_cgroup(void)
3055 {
3056 }
3057 #endif
3058
3059 static int mem_cgroup_soft_limit_tree_init(void)
3060 {
3061         struct mem_cgroup_tree_per_node *rtpn;
3062         struct mem_cgroup_tree_per_zone *rtpz;
3063         int tmp, node, zone;
3064
3065         for_each_node_state(node, N_POSSIBLE) {
3066                 tmp = node;
3067                 if (!node_state(node, N_NORMAL_MEMORY))
3068                         tmp = -1;
3069                 rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL, tmp);
3070                 if (!rtpn)
3071                         return 1;
3072
3073                 soft_limit_tree.rb_tree_per_node[node] = rtpn;
3074
3075                 for (zone = 0; zone < MAX_NR_ZONES; zone++) {
3076                         rtpz = &rtpn->rb_tree_per_zone[zone];
3077                         rtpz->rb_root = RB_ROOT;
3078                         spin_lock_init(&rtpz->lock);
3079                 }
3080         }
3081         return 0;
3082 }
3083
3084 static struct cgroup_subsys_state * __ref
3085 mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
3086 {
3087         struct mem_cgroup *mem, *parent;
3088         long error = -ENOMEM;
3089         int node;
3090
3091         mem = mem_cgroup_alloc();
3092         if (!mem)
3093                 return ERR_PTR(error);
3094
3095         for_each_node_state(node, N_POSSIBLE)
3096                 if (alloc_mem_cgroup_per_zone_info(mem, node))
3097                         goto free_out;
3098
3099         /* root ? */
3100         if (cont->parent == NULL) {
3101                 enable_swap_cgroup();
3102                 parent = NULL;
3103                 root_mem_cgroup = mem;
3104                 if (mem_cgroup_soft_limit_tree_init())
3105                         goto free_out;
3106
3107         } else {
3108                 parent = mem_cgroup_from_cont(cont->parent);
3109                 mem->use_hierarchy = parent->use_hierarchy;
3110         }
3111
3112         if (parent && parent->use_hierarchy) {
3113                 res_counter_init(&mem->res, &parent->res);
3114                 res_counter_init(&mem->memsw, &parent->memsw);
3115                 /*
3116                  * We increment refcnt of the parent to ensure that we can
3117                  * safely access it on res_counter_charge/uncharge.
3118                  * This refcnt will be decremented when freeing this
3119                  * mem_cgroup(see mem_cgroup_put).
3120                  */
3121                 mem_cgroup_get(parent);
3122         } else {
3123                 res_counter_init(&mem->res, NULL);
3124                 res_counter_init(&mem->memsw, NULL);
3125         }
3126         mem->last_scanned_child = 0;
3127         spin_lock_init(&mem->reclaim_param_lock);
3128
3129         if (parent)
3130                 mem->swappiness = get_swappiness(parent);
3131         atomic_set(&mem->refcnt, 1);
3132         return &mem->css;
3133 free_out:
3134         __mem_cgroup_free(mem);
3135         root_mem_cgroup = NULL;
3136         return ERR_PTR(error);
3137 }
3138
3139 static int mem_cgroup_pre_destroy(struct cgroup_subsys *ss,
3140                                         struct cgroup *cont)
3141 {
3142         struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
3143
3144         return mem_cgroup_force_empty(mem, false);
3145 }
3146
3147 static void mem_cgroup_destroy(struct cgroup_subsys *ss,
3148                                 struct cgroup *cont)
3149 {
3150         struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
3151
3152         mem_cgroup_put(mem);
3153 }
3154
3155 static int mem_cgroup_populate(struct cgroup_subsys *ss,
3156                                 struct cgroup *cont)
3157 {
3158         int ret;
3159
3160         ret = cgroup_add_files(cont, ss, mem_cgroup_files,
3161                                 ARRAY_SIZE(mem_cgroup_files));
3162
3163         if (!ret)
3164                 ret = register_memsw_files(cont, ss);
3165         return ret;
3166 }
3167
3168 static void mem_cgroup_move_task(struct cgroup_subsys *ss,
3169                                 struct cgroup *cont,
3170                                 struct cgroup *old_cont,
3171                                 struct task_struct *p,
3172                                 bool threadgroup)
3173 {
3174         mutex_lock(&memcg_tasklist);
3175         /*
3176          * FIXME: It's better to move charges of this process from old
3177          * memcg to new memcg. But it's just on TODO-List now.
3178          */
3179         mutex_unlock(&memcg_tasklist);
3180 }
3181
3182 struct cgroup_subsys mem_cgroup_subsys = {
3183         .name = "memory",
3184         .subsys_id = mem_cgroup_subsys_id,
3185         .create = mem_cgroup_create,
3186         .pre_destroy = mem_cgroup_pre_destroy,
3187         .destroy = mem_cgroup_destroy,
3188         .populate = mem_cgroup_populate,
3189         .attach = mem_cgroup_move_task,
3190         .early_init = 0,
3191         .use_id = 1,
3192 };
3193
3194 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
3195
3196 static int __init disable_swap_account(char *s)
3197 {
3198         really_do_swap_account = 0;
3199         return 1;
3200 }
3201 __setup("noswapaccount", disable_swap_account);
3202 #endif