arm: tegra: raise cpu floor when display is on
[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  * Memory thresholds
10  * Copyright (C) 2009 Nokia Corporation
11  * Author: Kirill A. Shutemov
12  *
13  * This program is free software; you can redistribute it and/or modify
14  * it under the terms of the GNU General Public License as published by
15  * the Free Software Foundation; either version 2 of the License, or
16  * (at your option) any later version.
17  *
18  * This program is distributed in the hope that it will be useful,
19  * but WITHOUT ANY WARRANTY; without even the implied warranty of
20  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
21  * GNU General Public License for more details.
22  */
23
24 #include <linux/res_counter.h>
25 #include <linux/memcontrol.h>
26 #include <linux/cgroup.h>
27 #include <linux/mm.h>
28 #include <linux/hugetlb.h>
29 #include <linux/pagemap.h>
30 #include <linux/smp.h>
31 #include <linux/page-flags.h>
32 #include <linux/backing-dev.h>
33 #include <linux/bit_spinlock.h>
34 #include <linux/rcupdate.h>
35 #include <linux/limits.h>
36 #include <linux/mutex.h>
37 #include <linux/rbtree.h>
38 #include <linux/slab.h>
39 #include <linux/swap.h>
40 #include <linux/swapops.h>
41 #include <linux/spinlock.h>
42 #include <linux/eventfd.h>
43 #include <linux/sort.h>
44 #include <linux/fs.h>
45 #include <linux/seq_file.h>
46 #include <linux/vmalloc.h>
47 #include <linux/mm_inline.h>
48 #include <linux/page_cgroup.h>
49 #include <linux/cpu.h>
50 #include <linux/oom.h>
51 #include "internal.h"
52
53 #include <asm/uaccess.h>
54
55 #include <trace/events/vmscan.h>
56
57 struct cgroup_subsys mem_cgroup_subsys __read_mostly;
58 #define MEM_CGROUP_RECLAIM_RETRIES      5
59 struct mem_cgroup *root_mem_cgroup __read_mostly;
60
61 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
62 /* Turned on only when memory cgroup is enabled && really_do_swap_account = 1 */
63 int do_swap_account __read_mostly;
64
65 /* for remember boot option*/
66 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP_ENABLED
67 static int really_do_swap_account __initdata = 1;
68 #else
69 static int really_do_swap_account __initdata = 0;
70 #endif
71
72 #else
73 #define do_swap_account         (0)
74 #endif
75
76
77 /*
78  * Statistics for memory cgroup.
79  */
80 enum mem_cgroup_stat_index {
81         /*
82          * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss.
83          */
84         MEM_CGROUP_STAT_CACHE,     /* # of pages charged as cache */
85         MEM_CGROUP_STAT_RSS,       /* # of pages charged as anon rss */
86         MEM_CGROUP_STAT_FILE_MAPPED,  /* # of pages charged as file rss */
87         MEM_CGROUP_STAT_SWAPOUT, /* # of pages, swapped out */
88         MEM_CGROUP_STAT_DATA, /* end of data requires synchronization */
89         MEM_CGROUP_ON_MOVE,     /* someone is moving account between groups */
90         MEM_CGROUP_STAT_NSTATS,
91 };
92
93 enum mem_cgroup_events_index {
94         MEM_CGROUP_EVENTS_PGPGIN,       /* # of pages paged in */
95         MEM_CGROUP_EVENTS_PGPGOUT,      /* # of pages paged out */
96         MEM_CGROUP_EVENTS_COUNT,        /* # of pages paged in/out */
97         MEM_CGROUP_EVENTS_PGFAULT,      /* # of page-faults */
98         MEM_CGROUP_EVENTS_PGMAJFAULT,   /* # of major page-faults */
99         MEM_CGROUP_EVENTS_NSTATS,
100 };
101 /*
102  * Per memcg event counter is incremented at every pagein/pageout. With THP,
103  * it will be incremated by the number of pages. This counter is used for
104  * for trigger some periodic events. This is straightforward and better
105  * than using jiffies etc. to handle periodic memcg event.
106  */
107 enum mem_cgroup_events_target {
108         MEM_CGROUP_TARGET_THRESH,
109         MEM_CGROUP_TARGET_SOFTLIMIT,
110         MEM_CGROUP_TARGET_NUMAINFO,
111         MEM_CGROUP_NTARGETS,
112 };
113 #define THRESHOLDS_EVENTS_TARGET (128)
114 #define SOFTLIMIT_EVENTS_TARGET (1024)
115 #define NUMAINFO_EVENTS_TARGET  (1024)
116
117 struct mem_cgroup_stat_cpu {
118         long count[MEM_CGROUP_STAT_NSTATS];
119         unsigned long events[MEM_CGROUP_EVENTS_NSTATS];
120         unsigned long targets[MEM_CGROUP_NTARGETS];
121 };
122
123 /*
124  * per-zone information in memory controller.
125  */
126 struct mem_cgroup_per_zone {
127         /*
128          * spin_lock to protect the per cgroup LRU
129          */
130         struct list_head        lists[NR_LRU_LISTS];
131         unsigned long           count[NR_LRU_LISTS];
132
133         struct zone_reclaim_stat reclaim_stat;
134         struct rb_node          tree_node;      /* RB tree node */
135         unsigned long long      usage_in_excess;/* Set to the value by which */
136                                                 /* the soft limit is exceeded*/
137         bool                    on_tree;
138         struct mem_cgroup       *mem;           /* Back pointer, we cannot */
139                                                 /* use container_of        */
140 };
141 /* Macro for accessing counter */
142 #define MEM_CGROUP_ZSTAT(mz, idx)       ((mz)->count[(idx)])
143
144 struct mem_cgroup_per_node {
145         struct mem_cgroup_per_zone zoneinfo[MAX_NR_ZONES];
146 };
147
148 struct mem_cgroup_lru_info {
149         struct mem_cgroup_per_node *nodeinfo[MAX_NUMNODES];
150 };
151
152 /*
153  * Cgroups above their limits are maintained in a RB-Tree, independent of
154  * their hierarchy representation
155  */
156
157 struct mem_cgroup_tree_per_zone {
158         struct rb_root rb_root;
159         spinlock_t lock;
160 };
161
162 struct mem_cgroup_tree_per_node {
163         struct mem_cgroup_tree_per_zone rb_tree_per_zone[MAX_NR_ZONES];
164 };
165
166 struct mem_cgroup_tree {
167         struct mem_cgroup_tree_per_node *rb_tree_per_node[MAX_NUMNODES];
168 };
169
170 static struct mem_cgroup_tree soft_limit_tree __read_mostly;
171
172 struct mem_cgroup_threshold {
173         struct eventfd_ctx *eventfd;
174         u64 threshold;
175 };
176
177 /* For threshold */
178 struct mem_cgroup_threshold_ary {
179         /* An array index points to threshold just below usage. */
180         int current_threshold;
181         /* Size of entries[] */
182         unsigned int size;
183         /* Array of thresholds */
184         struct mem_cgroup_threshold entries[0];
185 };
186
187 struct mem_cgroup_thresholds {
188         /* Primary thresholds array */
189         struct mem_cgroup_threshold_ary *primary;
190         /*
191          * Spare threshold array.
192          * This is needed to make mem_cgroup_unregister_event() "never fail".
193          * It must be able to store at least primary->size - 1 entries.
194          */
195         struct mem_cgroup_threshold_ary *spare;
196 };
197
198 /* for OOM */
199 struct mem_cgroup_eventfd_list {
200         struct list_head list;
201         struct eventfd_ctx *eventfd;
202 };
203
204 static void mem_cgroup_threshold(struct mem_cgroup *mem);
205 static void mem_cgroup_oom_notify(struct mem_cgroup *mem);
206
207 /*
208  * The memory controller data structure. The memory controller controls both
209  * page cache and RSS per cgroup. We would eventually like to provide
210  * statistics based on the statistics developed by Rik Van Riel for clock-pro,
211  * to help the administrator determine what knobs to tune.
212  *
213  * TODO: Add a water mark for the memory controller. Reclaim will begin when
214  * we hit the water mark. May be even add a low water mark, such that
215  * no reclaim occurs from a cgroup at it's low water mark, this is
216  * a feature that will be implemented much later in the future.
217  */
218 struct mem_cgroup {
219         struct cgroup_subsys_state css;
220         /*
221          * the counter to account for memory usage
222          */
223         struct res_counter res;
224         /*
225          * the counter to account for mem+swap usage.
226          */
227         struct res_counter memsw;
228         /*
229          * Per cgroup active and inactive list, similar to the
230          * per zone LRU lists.
231          */
232         struct mem_cgroup_lru_info info;
233         /*
234          * While reclaiming in a hierarchy, we cache the last child we
235          * reclaimed from.
236          */
237         int last_scanned_child;
238         int last_scanned_node;
239 #if MAX_NUMNODES > 1
240         nodemask_t      scan_nodes;
241         atomic_t        numainfo_events;
242         atomic_t        numainfo_updating;
243 #endif
244         /*
245          * Should the accounting and control be hierarchical, per subtree?
246          */
247         bool use_hierarchy;
248
249         bool            oom_lock;
250         atomic_t        under_oom;
251
252         atomic_t        refcnt;
253
254         int     swappiness;
255         /* OOM-Killer disable */
256         int             oom_kill_disable;
257
258         /* set when res.limit == memsw.limit */
259         bool            memsw_is_minimum;
260
261         /* protect arrays of thresholds */
262         struct mutex thresholds_lock;
263
264         /* thresholds for memory usage. RCU-protected */
265         struct mem_cgroup_thresholds thresholds;
266
267         /* thresholds for mem+swap usage. RCU-protected */
268         struct mem_cgroup_thresholds memsw_thresholds;
269
270         /* For oom notifier event fd */
271         struct list_head oom_notify;
272
273         /*
274          * Should we move charges of a task when a task is moved into this
275          * mem_cgroup ? And what type of charges should we move ?
276          */
277         unsigned long   move_charge_at_immigrate;
278         /*
279          * percpu counter.
280          */
281         struct mem_cgroup_stat_cpu *stat;
282         /*
283          * used when a cpu is offlined or other synchronizations
284          * See mem_cgroup_read_stat().
285          */
286         struct mem_cgroup_stat_cpu nocpu_base;
287         spinlock_t pcp_counter_lock;
288 };
289
290 /* Stuffs for move charges at task migration. */
291 /*
292  * Types of charges to be moved. "move_charge_at_immitgrate" is treated as a
293  * left-shifted bitmap of these types.
294  */
295 enum move_type {
296         MOVE_CHARGE_TYPE_ANON,  /* private anonymous page and swap of it */
297         MOVE_CHARGE_TYPE_FILE,  /* file page(including tmpfs) and swap of it */
298         NR_MOVE_TYPE,
299 };
300
301 /* "mc" and its members are protected by cgroup_mutex */
302 static struct move_charge_struct {
303         spinlock_t        lock; /* for from, to */
304         struct mem_cgroup *from;
305         struct mem_cgroup *to;
306         unsigned long precharge;
307         unsigned long moved_charge;
308         unsigned long moved_swap;
309         struct task_struct *moving_task;        /* a task moving charges */
310         wait_queue_head_t waitq;                /* a waitq for other context */
311 } mc = {
312         .lock = __SPIN_LOCK_UNLOCKED(mc.lock),
313         .waitq = __WAIT_QUEUE_HEAD_INITIALIZER(mc.waitq),
314 };
315
316 static bool move_anon(void)
317 {
318         return test_bit(MOVE_CHARGE_TYPE_ANON,
319                                         &mc.to->move_charge_at_immigrate);
320 }
321
322 static bool move_file(void)
323 {
324         return test_bit(MOVE_CHARGE_TYPE_FILE,
325                                         &mc.to->move_charge_at_immigrate);
326 }
327
328 /*
329  * Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft
330  * limit reclaim to prevent infinite loops, if they ever occur.
331  */
332 #define MEM_CGROUP_MAX_RECLAIM_LOOPS            (100)
333 #define MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS (2)
334
335 enum charge_type {
336         MEM_CGROUP_CHARGE_TYPE_CACHE = 0,
337         MEM_CGROUP_CHARGE_TYPE_MAPPED,
338         MEM_CGROUP_CHARGE_TYPE_SHMEM,   /* used by page migration of shmem */
339         MEM_CGROUP_CHARGE_TYPE_FORCE,   /* used by force_empty */
340         MEM_CGROUP_CHARGE_TYPE_SWAPOUT, /* for accounting swapcache */
341         MEM_CGROUP_CHARGE_TYPE_DROP,    /* a page was unused swap cache */
342         NR_CHARGE_TYPE,
343 };
344
345 /* for encoding cft->private value on file */
346 #define _MEM                    (0)
347 #define _MEMSWAP                (1)
348 #define _OOM_TYPE               (2)
349 #define MEMFILE_PRIVATE(x, val) (((x) << 16) | (val))
350 #define MEMFILE_TYPE(val)       (((val) >> 16) & 0xffff)
351 #define MEMFILE_ATTR(val)       ((val) & 0xffff)
352 /* Used for OOM nofiier */
353 #define OOM_CONTROL             (0)
354
355 /*
356  * Reclaim flags for mem_cgroup_hierarchical_reclaim
357  */
358 #define MEM_CGROUP_RECLAIM_NOSWAP_BIT   0x0
359 #define MEM_CGROUP_RECLAIM_NOSWAP       (1 << MEM_CGROUP_RECLAIM_NOSWAP_BIT)
360 #define MEM_CGROUP_RECLAIM_SHRINK_BIT   0x1
361 #define MEM_CGROUP_RECLAIM_SHRINK       (1 << MEM_CGROUP_RECLAIM_SHRINK_BIT)
362 #define MEM_CGROUP_RECLAIM_SOFT_BIT     0x2
363 #define MEM_CGROUP_RECLAIM_SOFT         (1 << MEM_CGROUP_RECLAIM_SOFT_BIT)
364
365 static void mem_cgroup_get(struct mem_cgroup *mem);
366 static void mem_cgroup_put(struct mem_cgroup *mem);
367 static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem);
368 static void drain_all_stock_async(struct mem_cgroup *mem);
369
370 static struct mem_cgroup_per_zone *
371 mem_cgroup_zoneinfo(struct mem_cgroup *mem, int nid, int zid)
372 {
373         return &mem->info.nodeinfo[nid]->zoneinfo[zid];
374 }
375
376 struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *mem)
377 {
378         return &mem->css;
379 }
380
381 static struct mem_cgroup_per_zone *
382 page_cgroup_zoneinfo(struct mem_cgroup *mem, struct page *page)
383 {
384         int nid = page_to_nid(page);
385         int zid = page_zonenum(page);
386
387         return mem_cgroup_zoneinfo(mem, nid, zid);
388 }
389
390 static struct mem_cgroup_tree_per_zone *
391 soft_limit_tree_node_zone(int nid, int zid)
392 {
393         return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid];
394 }
395
396 static struct mem_cgroup_tree_per_zone *
397 soft_limit_tree_from_page(struct page *page)
398 {
399         int nid = page_to_nid(page);
400         int zid = page_zonenum(page);
401
402         return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid];
403 }
404
405 static void
406 __mem_cgroup_insert_exceeded(struct mem_cgroup *mem,
407                                 struct mem_cgroup_per_zone *mz,
408                                 struct mem_cgroup_tree_per_zone *mctz,
409                                 unsigned long long new_usage_in_excess)
410 {
411         struct rb_node **p = &mctz->rb_root.rb_node;
412         struct rb_node *parent = NULL;
413         struct mem_cgroup_per_zone *mz_node;
414
415         if (mz->on_tree)
416                 return;
417
418         mz->usage_in_excess = new_usage_in_excess;
419         if (!mz->usage_in_excess)
420                 return;
421         while (*p) {
422                 parent = *p;
423                 mz_node = rb_entry(parent, struct mem_cgroup_per_zone,
424                                         tree_node);
425                 if (mz->usage_in_excess < mz_node->usage_in_excess)
426                         p = &(*p)->rb_left;
427                 /*
428                  * We can't avoid mem cgroups that are over their soft
429                  * limit by the same amount
430                  */
431                 else if (mz->usage_in_excess >= mz_node->usage_in_excess)
432                         p = &(*p)->rb_right;
433         }
434         rb_link_node(&mz->tree_node, parent, p);
435         rb_insert_color(&mz->tree_node, &mctz->rb_root);
436         mz->on_tree = true;
437 }
438
439 static void
440 __mem_cgroup_remove_exceeded(struct mem_cgroup *mem,
441                                 struct mem_cgroup_per_zone *mz,
442                                 struct mem_cgroup_tree_per_zone *mctz)
443 {
444         if (!mz->on_tree)
445                 return;
446         rb_erase(&mz->tree_node, &mctz->rb_root);
447         mz->on_tree = false;
448 }
449
450 static void
451 mem_cgroup_remove_exceeded(struct mem_cgroup *mem,
452                                 struct mem_cgroup_per_zone *mz,
453                                 struct mem_cgroup_tree_per_zone *mctz)
454 {
455         spin_lock(&mctz->lock);
456         __mem_cgroup_remove_exceeded(mem, mz, mctz);
457         spin_unlock(&mctz->lock);
458 }
459
460
461 static void mem_cgroup_update_tree(struct mem_cgroup *mem, struct page *page)
462 {
463         unsigned long long excess;
464         struct mem_cgroup_per_zone *mz;
465         struct mem_cgroup_tree_per_zone *mctz;
466         int nid = page_to_nid(page);
467         int zid = page_zonenum(page);
468         mctz = soft_limit_tree_from_page(page);
469
470         /*
471          * Necessary to update all ancestors when hierarchy is used.
472          * because their event counter is not touched.
473          */
474         for (; mem; mem = parent_mem_cgroup(mem)) {
475                 mz = mem_cgroup_zoneinfo(mem, nid, zid);
476                 excess = res_counter_soft_limit_excess(&mem->res);
477                 /*
478                  * We have to update the tree if mz is on RB-tree or
479                  * mem is over its softlimit.
480                  */
481                 if (excess || mz->on_tree) {
482                         spin_lock(&mctz->lock);
483                         /* if on-tree, remove it */
484                         if (mz->on_tree)
485                                 __mem_cgroup_remove_exceeded(mem, mz, mctz);
486                         /*
487                          * Insert again. mz->usage_in_excess will be updated.
488                          * If excess is 0, no tree ops.
489                          */
490                         __mem_cgroup_insert_exceeded(mem, mz, mctz, excess);
491                         spin_unlock(&mctz->lock);
492                 }
493         }
494 }
495
496 static void mem_cgroup_remove_from_trees(struct mem_cgroup *mem)
497 {
498         int node, zone;
499         struct mem_cgroup_per_zone *mz;
500         struct mem_cgroup_tree_per_zone *mctz;
501
502         for_each_node_state(node, N_POSSIBLE) {
503                 for (zone = 0; zone < MAX_NR_ZONES; zone++) {
504                         mz = mem_cgroup_zoneinfo(mem, node, zone);
505                         mctz = soft_limit_tree_node_zone(node, zone);
506                         mem_cgroup_remove_exceeded(mem, mz, mctz);
507                 }
508         }
509 }
510
511 static struct mem_cgroup_per_zone *
512 __mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
513 {
514         struct rb_node *rightmost = NULL;
515         struct mem_cgroup_per_zone *mz;
516
517 retry:
518         mz = NULL;
519         rightmost = rb_last(&mctz->rb_root);
520         if (!rightmost)
521                 goto done;              /* Nothing to reclaim from */
522
523         mz = rb_entry(rightmost, struct mem_cgroup_per_zone, tree_node);
524         /*
525          * Remove the node now but someone else can add it back,
526          * we will to add it back at the end of reclaim to its correct
527          * position in the tree.
528          */
529         __mem_cgroup_remove_exceeded(mz->mem, mz, mctz);
530         if (!res_counter_soft_limit_excess(&mz->mem->res) ||
531                 !css_tryget(&mz->mem->css))
532                 goto retry;
533 done:
534         return mz;
535 }
536
537 static struct mem_cgroup_per_zone *
538 mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
539 {
540         struct mem_cgroup_per_zone *mz;
541
542         spin_lock(&mctz->lock);
543         mz = __mem_cgroup_largest_soft_limit_node(mctz);
544         spin_unlock(&mctz->lock);
545         return mz;
546 }
547
548 /*
549  * Implementation Note: reading percpu statistics for memcg.
550  *
551  * Both of vmstat[] and percpu_counter has threshold and do periodic
552  * synchronization to implement "quick" read. There are trade-off between
553  * reading cost and precision of value. Then, we may have a chance to implement
554  * a periodic synchronizion of counter in memcg's counter.
555  *
556  * But this _read() function is used for user interface now. The user accounts
557  * memory usage by memory cgroup and he _always_ requires exact value because
558  * he accounts memory. Even if we provide quick-and-fuzzy read, we always
559  * have to visit all online cpus and make sum. So, for now, unnecessary
560  * synchronization is not implemented. (just implemented for cpu hotplug)
561  *
562  * If there are kernel internal actions which can make use of some not-exact
563  * value, and reading all cpu value can be performance bottleneck in some
564  * common workload, threashold and synchonization as vmstat[] should be
565  * implemented.
566  */
567 static long mem_cgroup_read_stat(struct mem_cgroup *mem,
568                                  enum mem_cgroup_stat_index idx)
569 {
570         long val = 0;
571         int cpu;
572
573         get_online_cpus();
574         for_each_online_cpu(cpu)
575                 val += per_cpu(mem->stat->count[idx], cpu);
576 #ifdef CONFIG_HOTPLUG_CPU
577         spin_lock(&mem->pcp_counter_lock);
578         val += mem->nocpu_base.count[idx];
579         spin_unlock(&mem->pcp_counter_lock);
580 #endif
581         put_online_cpus();
582         return val;
583 }
584
585 static void mem_cgroup_swap_statistics(struct mem_cgroup *mem,
586                                          bool charge)
587 {
588         int val = (charge) ? 1 : -1;
589         this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_SWAPOUT], val);
590 }
591
592 void mem_cgroup_pgfault(struct mem_cgroup *mem, int val)
593 {
594         this_cpu_add(mem->stat->events[MEM_CGROUP_EVENTS_PGFAULT], val);
595 }
596
597 void mem_cgroup_pgmajfault(struct mem_cgroup *mem, int val)
598 {
599         this_cpu_add(mem->stat->events[MEM_CGROUP_EVENTS_PGMAJFAULT], val);
600 }
601
602 static unsigned long mem_cgroup_read_events(struct mem_cgroup *mem,
603                                             enum mem_cgroup_events_index idx)
604 {
605         unsigned long val = 0;
606         int cpu;
607
608         for_each_online_cpu(cpu)
609                 val += per_cpu(mem->stat->events[idx], cpu);
610 #ifdef CONFIG_HOTPLUG_CPU
611         spin_lock(&mem->pcp_counter_lock);
612         val += mem->nocpu_base.events[idx];
613         spin_unlock(&mem->pcp_counter_lock);
614 #endif
615         return val;
616 }
617
618 static void mem_cgroup_charge_statistics(struct mem_cgroup *mem,
619                                          bool file, int nr_pages)
620 {
621         preempt_disable();
622
623         if (file)
624                 __this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_CACHE], nr_pages);
625         else
626                 __this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_RSS], nr_pages);
627
628         /* pagein of a big page is an event. So, ignore page size */
629         if (nr_pages > 0)
630                 __this_cpu_inc(mem->stat->events[MEM_CGROUP_EVENTS_PGPGIN]);
631         else {
632                 __this_cpu_inc(mem->stat->events[MEM_CGROUP_EVENTS_PGPGOUT]);
633                 nr_pages = -nr_pages; /* for event */
634         }
635
636         __this_cpu_add(mem->stat->events[MEM_CGROUP_EVENTS_COUNT], nr_pages);
637
638         preempt_enable();
639 }
640
641 unsigned long
642 mem_cgroup_zone_nr_lru_pages(struct mem_cgroup *mem, int nid, int zid,
643                         unsigned int lru_mask)
644 {
645         struct mem_cgroup_per_zone *mz;
646         enum lru_list l;
647         unsigned long ret = 0;
648
649         mz = mem_cgroup_zoneinfo(mem, nid, zid);
650
651         for_each_lru(l) {
652                 if (BIT(l) & lru_mask)
653                         ret += MEM_CGROUP_ZSTAT(mz, l);
654         }
655         return ret;
656 }
657
658 static unsigned long
659 mem_cgroup_node_nr_lru_pages(struct mem_cgroup *mem,
660                         int nid, unsigned int lru_mask)
661 {
662         u64 total = 0;
663         int zid;
664
665         for (zid = 0; zid < MAX_NR_ZONES; zid++)
666                 total += mem_cgroup_zone_nr_lru_pages(mem, nid, zid, lru_mask);
667
668         return total;
669 }
670
671 static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup *mem,
672                         unsigned int lru_mask)
673 {
674         int nid;
675         u64 total = 0;
676
677         for_each_node_state(nid, N_HIGH_MEMORY)
678                 total += mem_cgroup_node_nr_lru_pages(mem, nid, lru_mask);
679         return total;
680 }
681
682 static bool __memcg_event_check(struct mem_cgroup *mem, int target)
683 {
684         unsigned long val, next;
685
686         val = this_cpu_read(mem->stat->events[MEM_CGROUP_EVENTS_COUNT]);
687         next = this_cpu_read(mem->stat->targets[target]);
688         /* from time_after() in jiffies.h */
689         return ((long)next - (long)val < 0);
690 }
691
692 static void __mem_cgroup_target_update(struct mem_cgroup *mem, int target)
693 {
694         unsigned long val, next;
695
696         val = this_cpu_read(mem->stat->events[MEM_CGROUP_EVENTS_COUNT]);
697
698         switch (target) {
699         case MEM_CGROUP_TARGET_THRESH:
700                 next = val + THRESHOLDS_EVENTS_TARGET;
701                 break;
702         case MEM_CGROUP_TARGET_SOFTLIMIT:
703                 next = val + SOFTLIMIT_EVENTS_TARGET;
704                 break;
705         case MEM_CGROUP_TARGET_NUMAINFO:
706                 next = val + NUMAINFO_EVENTS_TARGET;
707                 break;
708         default:
709                 return;
710         }
711
712         this_cpu_write(mem->stat->targets[target], next);
713 }
714
715 /*
716  * Check events in order.
717  *
718  */
719 static void memcg_check_events(struct mem_cgroup *mem, struct page *page)
720 {
721         /* threshold event is triggered in finer grain than soft limit */
722         if (unlikely(__memcg_event_check(mem, MEM_CGROUP_TARGET_THRESH))) {
723                 mem_cgroup_threshold(mem);
724                 __mem_cgroup_target_update(mem, MEM_CGROUP_TARGET_THRESH);
725                 if (unlikely(__memcg_event_check(mem,
726                              MEM_CGROUP_TARGET_SOFTLIMIT))) {
727                         mem_cgroup_update_tree(mem, page);
728                         __mem_cgroup_target_update(mem,
729                                                    MEM_CGROUP_TARGET_SOFTLIMIT);
730                 }
731 #if MAX_NUMNODES > 1
732                 if (unlikely(__memcg_event_check(mem,
733                         MEM_CGROUP_TARGET_NUMAINFO))) {
734                         atomic_inc(&mem->numainfo_events);
735                         __mem_cgroup_target_update(mem,
736                                 MEM_CGROUP_TARGET_NUMAINFO);
737                 }
738 #endif
739         }
740 }
741
742 static struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont)
743 {
744         return container_of(cgroup_subsys_state(cont,
745                                 mem_cgroup_subsys_id), struct mem_cgroup,
746                                 css);
747 }
748
749 struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
750 {
751         /*
752          * mm_update_next_owner() may clear mm->owner to NULL
753          * if it races with swapoff, page migration, etc.
754          * So this can be called with p == NULL.
755          */
756         if (unlikely(!p))
757                 return NULL;
758
759         return container_of(task_subsys_state(p, mem_cgroup_subsys_id),
760                                 struct mem_cgroup, css);
761 }
762
763 struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm)
764 {
765         struct mem_cgroup *mem = NULL;
766
767         if (!mm)
768                 return NULL;
769         /*
770          * Because we have no locks, mm->owner's may be being moved to other
771          * cgroup. We use css_tryget() here even if this looks
772          * pessimistic (rather than adding locks here).
773          */
774         rcu_read_lock();
775         do {
776                 mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
777                 if (unlikely(!mem))
778                         break;
779         } while (!css_tryget(&mem->css));
780         rcu_read_unlock();
781         return mem;
782 }
783
784 /* The caller has to guarantee "mem" exists before calling this */
785 static struct mem_cgroup *mem_cgroup_start_loop(struct mem_cgroup *mem)
786 {
787         struct cgroup_subsys_state *css;
788         int found;
789
790         if (!mem) /* ROOT cgroup has the smallest ID */
791                 return root_mem_cgroup; /*css_put/get against root is ignored*/
792         if (!mem->use_hierarchy) {
793                 if (css_tryget(&mem->css))
794                         return mem;
795                 return NULL;
796         }
797         rcu_read_lock();
798         /*
799          * searching a memory cgroup which has the smallest ID under given
800          * ROOT cgroup. (ID >= 1)
801          */
802         css = css_get_next(&mem_cgroup_subsys, 1, &mem->css, &found);
803         if (css && css_tryget(css))
804                 mem = container_of(css, struct mem_cgroup, css);
805         else
806                 mem = NULL;
807         rcu_read_unlock();
808         return mem;
809 }
810
811 static struct mem_cgroup *mem_cgroup_get_next(struct mem_cgroup *iter,
812                                         struct mem_cgroup *root,
813                                         bool cond)
814 {
815         int nextid = css_id(&iter->css) + 1;
816         int found;
817         int hierarchy_used;
818         struct cgroup_subsys_state *css;
819
820         hierarchy_used = iter->use_hierarchy;
821
822         css_put(&iter->css);
823         /* If no ROOT, walk all, ignore hierarchy */
824         if (!cond || (root && !hierarchy_used))
825                 return NULL;
826
827         if (!root)
828                 root = root_mem_cgroup;
829
830         do {
831                 iter = NULL;
832                 rcu_read_lock();
833
834                 css = css_get_next(&mem_cgroup_subsys, nextid,
835                                 &root->css, &found);
836                 if (css && css_tryget(css))
837                         iter = container_of(css, struct mem_cgroup, css);
838                 rcu_read_unlock();
839                 /* If css is NULL, no more cgroups will be found */
840                 nextid = found + 1;
841         } while (css && !iter);
842
843         return iter;
844 }
845 /*
846  * for_eacn_mem_cgroup_tree() for visiting all cgroup under tree. Please
847  * be careful that "break" loop is not allowed. We have reference count.
848  * Instead of that modify "cond" to be false and "continue" to exit the loop.
849  */
850 #define for_each_mem_cgroup_tree_cond(iter, root, cond) \
851         for (iter = mem_cgroup_start_loop(root);\
852              iter != NULL;\
853              iter = mem_cgroup_get_next(iter, root, cond))
854
855 #define for_each_mem_cgroup_tree(iter, root) \
856         for_each_mem_cgroup_tree_cond(iter, root, true)
857
858 #define for_each_mem_cgroup_all(iter) \
859         for_each_mem_cgroup_tree_cond(iter, NULL, true)
860
861
862 static inline bool mem_cgroup_is_root(struct mem_cgroup *mem)
863 {
864         return (mem == root_mem_cgroup);
865 }
866
867 void mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx)
868 {
869         struct mem_cgroup *mem;
870
871         if (!mm)
872                 return;
873
874         rcu_read_lock();
875         mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
876         if (unlikely(!mem))
877                 goto out;
878
879         switch (idx) {
880         case PGMAJFAULT:
881                 mem_cgroup_pgmajfault(mem, 1);
882                 break;
883         case PGFAULT:
884                 mem_cgroup_pgfault(mem, 1);
885                 break;
886         default:
887                 BUG();
888         }
889 out:
890         rcu_read_unlock();
891 }
892 EXPORT_SYMBOL(mem_cgroup_count_vm_event);
893
894 /*
895  * Following LRU functions are allowed to be used without PCG_LOCK.
896  * Operations are called by routine of global LRU independently from memcg.
897  * What we have to take care of here is validness of pc->mem_cgroup.
898  *
899  * Changes to pc->mem_cgroup happens when
900  * 1. charge
901  * 2. moving account
902  * In typical case, "charge" is done before add-to-lru. Exception is SwapCache.
903  * It is added to LRU before charge.
904  * If PCG_USED bit is not set, page_cgroup is not added to this private LRU.
905  * When moving account, the page is not on LRU. It's isolated.
906  */
907
908 void mem_cgroup_del_lru_list(struct page *page, enum lru_list lru)
909 {
910         struct page_cgroup *pc;
911         struct mem_cgroup_per_zone *mz;
912
913         if (mem_cgroup_disabled())
914                 return;
915         pc = lookup_page_cgroup(page);
916         /* can happen while we handle swapcache. */
917         if (!TestClearPageCgroupAcctLRU(pc))
918                 return;
919         VM_BUG_ON(!pc->mem_cgroup);
920         /*
921          * We don't check PCG_USED bit. It's cleared when the "page" is finally
922          * removed from global LRU.
923          */
924         mz = page_cgroup_zoneinfo(pc->mem_cgroup, page);
925         /* huge page split is done under lru_lock. so, we have no races. */
926         MEM_CGROUP_ZSTAT(mz, lru) -= 1 << compound_order(page);
927         if (mem_cgroup_is_root(pc->mem_cgroup))
928                 return;
929         VM_BUG_ON(list_empty(&pc->lru));
930         list_del_init(&pc->lru);
931 }
932
933 void mem_cgroup_del_lru(struct page *page)
934 {
935         mem_cgroup_del_lru_list(page, page_lru(page));
936 }
937
938 /*
939  * Writeback is about to end against a page which has been marked for immediate
940  * reclaim.  If it still appears to be reclaimable, move it to the tail of the
941  * inactive list.
942  */
943 void mem_cgroup_rotate_reclaimable_page(struct page *page)
944 {
945         struct mem_cgroup_per_zone *mz;
946         struct page_cgroup *pc;
947         enum lru_list lru = page_lru(page);
948
949         if (mem_cgroup_disabled())
950                 return;
951
952         pc = lookup_page_cgroup(page);
953         /* unused or root page is not rotated. */
954         if (!PageCgroupUsed(pc))
955                 return;
956         /* Ensure pc->mem_cgroup is visible after reading PCG_USED. */
957         smp_rmb();
958         if (mem_cgroup_is_root(pc->mem_cgroup))
959                 return;
960         mz = page_cgroup_zoneinfo(pc->mem_cgroup, page);
961         list_move_tail(&pc->lru, &mz->lists[lru]);
962 }
963
964 void mem_cgroup_rotate_lru_list(struct page *page, enum lru_list lru)
965 {
966         struct mem_cgroup_per_zone *mz;
967         struct page_cgroup *pc;
968
969         if (mem_cgroup_disabled())
970                 return;
971
972         pc = lookup_page_cgroup(page);
973         /* unused or root page is not rotated. */
974         if (!PageCgroupUsed(pc))
975                 return;
976         /* Ensure pc->mem_cgroup is visible after reading PCG_USED. */
977         smp_rmb();
978         if (mem_cgroup_is_root(pc->mem_cgroup))
979                 return;
980         mz = page_cgroup_zoneinfo(pc->mem_cgroup, page);
981         list_move(&pc->lru, &mz->lists[lru]);
982 }
983
984 void mem_cgroup_add_lru_list(struct page *page, enum lru_list lru)
985 {
986         struct page_cgroup *pc;
987         struct mem_cgroup_per_zone *mz;
988
989         if (mem_cgroup_disabled())
990                 return;
991         pc = lookup_page_cgroup(page);
992         VM_BUG_ON(PageCgroupAcctLRU(pc));
993         if (!PageCgroupUsed(pc))
994                 return;
995         /* Ensure pc->mem_cgroup is visible after reading PCG_USED. */
996         smp_rmb();
997         mz = page_cgroup_zoneinfo(pc->mem_cgroup, page);
998         /* huge page split is done under lru_lock. so, we have no races. */
999         MEM_CGROUP_ZSTAT(mz, lru) += 1 << compound_order(page);
1000         SetPageCgroupAcctLRU(pc);
1001         if (mem_cgroup_is_root(pc->mem_cgroup))
1002                 return;
1003         list_add(&pc->lru, &mz->lists[lru]);
1004 }
1005
1006 /*
1007  * At handling SwapCache and other FUSE stuff, pc->mem_cgroup may be changed
1008  * while it's linked to lru because the page may be reused after it's fully
1009  * uncharged. To handle that, unlink page_cgroup from LRU when charge it again.
1010  * It's done under lock_page and expected that zone->lru_lock isnever held.
1011  */
1012 static void mem_cgroup_lru_del_before_commit(struct page *page)
1013 {
1014         unsigned long flags;
1015         struct zone *zone = page_zone(page);
1016         struct page_cgroup *pc = lookup_page_cgroup(page);
1017
1018         /*
1019          * Doing this check without taking ->lru_lock seems wrong but this
1020          * is safe. Because if page_cgroup's USED bit is unset, the page
1021          * will not be added to any memcg's LRU. If page_cgroup's USED bit is
1022          * set, the commit after this will fail, anyway.
1023          * This all charge/uncharge is done under some mutual execustion.
1024          * So, we don't need to taking care of changes in USED bit.
1025          */
1026         if (likely(!PageLRU(page)))
1027                 return;
1028
1029         spin_lock_irqsave(&zone->lru_lock, flags);
1030         /*
1031          * Forget old LRU when this page_cgroup is *not* used. This Used bit
1032          * is guarded by lock_page() because the page is SwapCache.
1033          */
1034         if (!PageCgroupUsed(pc))
1035                 mem_cgroup_del_lru_list(page, page_lru(page));
1036         spin_unlock_irqrestore(&zone->lru_lock, flags);
1037 }
1038
1039 static void mem_cgroup_lru_add_after_commit(struct page *page)
1040 {
1041         unsigned long flags;
1042         struct zone *zone = page_zone(page);
1043         struct page_cgroup *pc = lookup_page_cgroup(page);
1044
1045         /* taking care of that the page is added to LRU while we commit it */
1046         if (likely(!PageLRU(page)))
1047                 return;
1048         spin_lock_irqsave(&zone->lru_lock, flags);
1049         /* link when the page is linked to LRU but page_cgroup isn't */
1050         if (PageLRU(page) && !PageCgroupAcctLRU(pc))
1051                 mem_cgroup_add_lru_list(page, page_lru(page));
1052         spin_unlock_irqrestore(&zone->lru_lock, flags);
1053 }
1054
1055
1056 void mem_cgroup_move_lists(struct page *page,
1057                            enum lru_list from, enum lru_list to)
1058 {
1059         if (mem_cgroup_disabled())
1060                 return;
1061         mem_cgroup_del_lru_list(page, from);
1062         mem_cgroup_add_lru_list(page, to);
1063 }
1064
1065 /*
1066  * Checks whether given mem is same or in the root_mem's
1067  * hierarchy subtree
1068  */
1069 static bool mem_cgroup_same_or_subtree(const struct mem_cgroup *root_mem,
1070                 struct mem_cgroup *mem)
1071 {
1072         if (root_mem != mem) {
1073                 return (root_mem->use_hierarchy &&
1074                         css_is_ancestor(&mem->css, &root_mem->css));
1075         }
1076
1077         return true;
1078 }
1079
1080 int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem)
1081 {
1082         int ret;
1083         struct mem_cgroup *curr = NULL;
1084         struct task_struct *p;
1085
1086         p = find_lock_task_mm(task);
1087         if (!p)
1088                 return 0;
1089         curr = try_get_mem_cgroup_from_mm(p->mm);
1090         task_unlock(p);
1091         if (!curr)
1092                 return 0;
1093         /*
1094          * We should check use_hierarchy of "mem" not "curr". Because checking
1095          * use_hierarchy of "curr" here make this function true if hierarchy is
1096          * enabled in "curr" and "curr" is a child of "mem" in *cgroup*
1097          * hierarchy(even if use_hierarchy is disabled in "mem").
1098          */
1099         ret = mem_cgroup_same_or_subtree(mem, curr);
1100         css_put(&curr->css);
1101         return ret;
1102 }
1103
1104 static int calc_inactive_ratio(struct mem_cgroup *memcg, unsigned long *present_pages)
1105 {
1106         unsigned long active;
1107         unsigned long inactive;
1108         unsigned long gb;
1109         unsigned long inactive_ratio;
1110
1111         inactive = mem_cgroup_nr_lru_pages(memcg, BIT(LRU_INACTIVE_ANON));
1112         active = mem_cgroup_nr_lru_pages(memcg, BIT(LRU_ACTIVE_ANON));
1113
1114         gb = (inactive + active) >> (30 - PAGE_SHIFT);
1115         if (gb)
1116                 inactive_ratio = int_sqrt(10 * gb);
1117         else
1118                 inactive_ratio = 1;
1119
1120         if (present_pages) {
1121                 present_pages[0] = inactive;
1122                 present_pages[1] = active;
1123         }
1124
1125         return inactive_ratio;
1126 }
1127
1128 int mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg)
1129 {
1130         unsigned long active;
1131         unsigned long inactive;
1132         unsigned long present_pages[2];
1133         unsigned long inactive_ratio;
1134
1135         inactive_ratio = calc_inactive_ratio(memcg, present_pages);
1136
1137         inactive = present_pages[0];
1138         active = present_pages[1];
1139
1140         if (inactive * inactive_ratio < active)
1141                 return 1;
1142
1143         return 0;
1144 }
1145
1146 int mem_cgroup_inactive_file_is_low(struct mem_cgroup *memcg)
1147 {
1148         unsigned long active;
1149         unsigned long inactive;
1150
1151         inactive = mem_cgroup_nr_lru_pages(memcg, BIT(LRU_INACTIVE_FILE));
1152         active = mem_cgroup_nr_lru_pages(memcg, BIT(LRU_ACTIVE_FILE));
1153
1154         return (active > inactive);
1155 }
1156
1157 struct zone_reclaim_stat *mem_cgroup_get_reclaim_stat(struct mem_cgroup *memcg,
1158                                                       struct zone *zone)
1159 {
1160         int nid = zone_to_nid(zone);
1161         int zid = zone_idx(zone);
1162         struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid);
1163
1164         return &mz->reclaim_stat;
1165 }
1166
1167 struct zone_reclaim_stat *
1168 mem_cgroup_get_reclaim_stat_from_page(struct page *page)
1169 {
1170         struct page_cgroup *pc;
1171         struct mem_cgroup_per_zone *mz;
1172
1173         if (mem_cgroup_disabled())
1174                 return NULL;
1175
1176         pc = lookup_page_cgroup(page);
1177         if (!PageCgroupUsed(pc))
1178                 return NULL;
1179         /* Ensure pc->mem_cgroup is visible after reading PCG_USED. */
1180         smp_rmb();
1181         mz = page_cgroup_zoneinfo(pc->mem_cgroup, page);
1182         return &mz->reclaim_stat;
1183 }
1184
1185 unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
1186                                         struct list_head *dst,
1187                                         unsigned long *scanned, int order,
1188                                         int mode, struct zone *z,
1189                                         struct mem_cgroup *mem_cont,
1190                                         int active, int file)
1191 {
1192         unsigned long nr_taken = 0;
1193         struct page *page;
1194         unsigned long scan;
1195         LIST_HEAD(pc_list);
1196         struct list_head *src;
1197         struct page_cgroup *pc, *tmp;
1198         int nid = zone_to_nid(z);
1199         int zid = zone_idx(z);
1200         struct mem_cgroup_per_zone *mz;
1201         int lru = LRU_FILE * file + active;
1202         int ret;
1203
1204         BUG_ON(!mem_cont);
1205         mz = mem_cgroup_zoneinfo(mem_cont, nid, zid);
1206         src = &mz->lists[lru];
1207
1208         scan = 0;
1209         list_for_each_entry_safe_reverse(pc, tmp, src, lru) {
1210                 if (scan >= nr_to_scan)
1211                         break;
1212
1213                 if (unlikely(!PageCgroupUsed(pc)))
1214                         continue;
1215
1216                 page = lookup_cgroup_page(pc);
1217
1218                 if (unlikely(!PageLRU(page)))
1219                         continue;
1220
1221                 scan++;
1222                 ret = __isolate_lru_page(page, mode, file);
1223                 switch (ret) {
1224                 case 0:
1225                         list_move(&page->lru, dst);
1226                         mem_cgroup_del_lru(page);
1227                         nr_taken += hpage_nr_pages(page);
1228                         break;
1229                 case -EBUSY:
1230                         /* we don't affect global LRU but rotate in our LRU */
1231                         mem_cgroup_rotate_lru_list(page, page_lru(page));
1232                         break;
1233                 default:
1234                         break;
1235                 }
1236         }
1237
1238         *scanned = scan;
1239
1240         trace_mm_vmscan_memcg_isolate(0, nr_to_scan, scan, nr_taken,
1241                                       0, 0, 0, mode);
1242
1243         return nr_taken;
1244 }
1245
1246 #define mem_cgroup_from_res_counter(counter, member)    \
1247         container_of(counter, struct mem_cgroup, member)
1248
1249 /**
1250  * mem_cgroup_margin - calculate chargeable space of a memory cgroup
1251  * @mem: the memory cgroup
1252  *
1253  * Returns the maximum amount of memory @mem can be charged with, in
1254  * pages.
1255  */
1256 static unsigned long mem_cgroup_margin(struct mem_cgroup *mem)
1257 {
1258         unsigned long long margin;
1259
1260         margin = res_counter_margin(&mem->res);
1261         if (do_swap_account)
1262                 margin = min(margin, res_counter_margin(&mem->memsw));
1263         return margin >> PAGE_SHIFT;
1264 }
1265
1266 int mem_cgroup_swappiness(struct mem_cgroup *memcg)
1267 {
1268         struct cgroup *cgrp = memcg->css.cgroup;
1269
1270         /* root ? */
1271         if (cgrp->parent == NULL)
1272                 return vm_swappiness;
1273
1274         return memcg->swappiness;
1275 }
1276
1277 static void mem_cgroup_start_move(struct mem_cgroup *mem)
1278 {
1279         int cpu;
1280
1281         get_online_cpus();
1282         spin_lock(&mem->pcp_counter_lock);
1283         for_each_online_cpu(cpu)
1284                 per_cpu(mem->stat->count[MEM_CGROUP_ON_MOVE], cpu) += 1;
1285         mem->nocpu_base.count[MEM_CGROUP_ON_MOVE] += 1;
1286         spin_unlock(&mem->pcp_counter_lock);
1287         put_online_cpus();
1288
1289         synchronize_rcu();
1290 }
1291
1292 static void mem_cgroup_end_move(struct mem_cgroup *mem)
1293 {
1294         int cpu;
1295
1296         if (!mem)
1297                 return;
1298         get_online_cpus();
1299         spin_lock(&mem->pcp_counter_lock);
1300         for_each_online_cpu(cpu)
1301                 per_cpu(mem->stat->count[MEM_CGROUP_ON_MOVE], cpu) -= 1;
1302         mem->nocpu_base.count[MEM_CGROUP_ON_MOVE] -= 1;
1303         spin_unlock(&mem->pcp_counter_lock);
1304         put_online_cpus();
1305 }
1306 /*
1307  * 2 routines for checking "mem" is under move_account() or not.
1308  *
1309  * mem_cgroup_stealed() - checking a cgroup is mc.from or not. This is used
1310  *                        for avoiding race in accounting. If true,
1311  *                        pc->mem_cgroup may be overwritten.
1312  *
1313  * mem_cgroup_under_move() - checking a cgroup is mc.from or mc.to or
1314  *                        under hierarchy of moving cgroups. This is for
1315  *                        waiting at hith-memory prressure caused by "move".
1316  */
1317
1318 static bool mem_cgroup_stealed(struct mem_cgroup *mem)
1319 {
1320         VM_BUG_ON(!rcu_read_lock_held());
1321         return this_cpu_read(mem->stat->count[MEM_CGROUP_ON_MOVE]) > 0;
1322 }
1323
1324 static bool mem_cgroup_under_move(struct mem_cgroup *mem)
1325 {
1326         struct mem_cgroup *from;
1327         struct mem_cgroup *to;
1328         bool ret = false;
1329         /*
1330          * Unlike task_move routines, we access mc.to, mc.from not under
1331          * mutual exclusion by cgroup_mutex. Here, we take spinlock instead.
1332          */
1333         spin_lock(&mc.lock);
1334         from = mc.from;
1335         to = mc.to;
1336         if (!from)
1337                 goto unlock;
1338
1339         ret = mem_cgroup_same_or_subtree(mem, from)
1340                 || mem_cgroup_same_or_subtree(mem, to);
1341 unlock:
1342         spin_unlock(&mc.lock);
1343         return ret;
1344 }
1345
1346 static bool mem_cgroup_wait_acct_move(struct mem_cgroup *mem)
1347 {
1348         if (mc.moving_task && current != mc.moving_task) {
1349                 if (mem_cgroup_under_move(mem)) {
1350                         DEFINE_WAIT(wait);
1351                         prepare_to_wait(&mc.waitq, &wait, TASK_INTERRUPTIBLE);
1352                         /* moving charge context might have finished. */
1353                         if (mc.moving_task)
1354                                 schedule();
1355                         finish_wait(&mc.waitq, &wait);
1356                         return true;
1357                 }
1358         }
1359         return false;
1360 }
1361
1362 /**
1363  * mem_cgroup_print_oom_info: Called from OOM with tasklist_lock held in read mode.
1364  * @memcg: The memory cgroup that went over limit
1365  * @p: Task that is going to be killed
1366  *
1367  * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is
1368  * enabled
1369  */
1370 void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
1371 {
1372         struct cgroup *task_cgrp;
1373         struct cgroup *mem_cgrp;
1374         /*
1375          * Need a buffer in BSS, can't rely on allocations. The code relies
1376          * on the assumption that OOM is serialized for memory controller.
1377          * If this assumption is broken, revisit this code.
1378          */
1379         static char memcg_name[PATH_MAX];
1380         int ret;
1381
1382         if (!memcg || !p)
1383                 return;
1384
1385
1386         rcu_read_lock();
1387
1388         mem_cgrp = memcg->css.cgroup;
1389         task_cgrp = task_cgroup(p, mem_cgroup_subsys_id);
1390
1391         ret = cgroup_path(task_cgrp, memcg_name, PATH_MAX);
1392         if (ret < 0) {
1393                 /*
1394                  * Unfortunately, we are unable to convert to a useful name
1395                  * But we'll still print out the usage information
1396                  */
1397                 rcu_read_unlock();
1398                 goto done;
1399         }
1400         rcu_read_unlock();
1401
1402         printk(KERN_INFO "Task in %s killed", memcg_name);
1403
1404         rcu_read_lock();
1405         ret = cgroup_path(mem_cgrp, memcg_name, PATH_MAX);
1406         if (ret < 0) {
1407                 rcu_read_unlock();
1408                 goto done;
1409         }
1410         rcu_read_unlock();
1411
1412         /*
1413          * Continues from above, so we don't need an KERN_ level
1414          */
1415         printk(KERN_CONT " as a result of limit of %s\n", memcg_name);
1416 done:
1417
1418         printk(KERN_INFO "memory: usage %llukB, limit %llukB, failcnt %llu\n",
1419                 res_counter_read_u64(&memcg->res, RES_USAGE) >> 10,
1420                 res_counter_read_u64(&memcg->res, RES_LIMIT) >> 10,
1421                 res_counter_read_u64(&memcg->res, RES_FAILCNT));
1422         printk(KERN_INFO "memory+swap: usage %llukB, limit %llukB, "
1423                 "failcnt %llu\n",
1424                 res_counter_read_u64(&memcg->memsw, RES_USAGE) >> 10,
1425                 res_counter_read_u64(&memcg->memsw, RES_LIMIT) >> 10,
1426                 res_counter_read_u64(&memcg->memsw, RES_FAILCNT));
1427 }
1428
1429 /*
1430  * This function returns the number of memcg under hierarchy tree. Returns
1431  * 1(self count) if no children.
1432  */
1433 static int mem_cgroup_count_children(struct mem_cgroup *mem)
1434 {
1435         int num = 0;
1436         struct mem_cgroup *iter;
1437
1438         for_each_mem_cgroup_tree(iter, mem)
1439                 num++;
1440         return num;
1441 }
1442
1443 /*
1444  * Return the memory (and swap, if configured) limit for a memcg.
1445  */
1446 u64 mem_cgroup_get_limit(struct mem_cgroup *memcg)
1447 {
1448         u64 limit;
1449         u64 memsw;
1450
1451         limit = res_counter_read_u64(&memcg->res, RES_LIMIT);
1452         limit += total_swap_pages << PAGE_SHIFT;
1453
1454         memsw = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
1455         /*
1456          * If memsw is finite and limits the amount of swap space available
1457          * to this memcg, return that limit.
1458          */
1459         return min(limit, memsw);
1460 }
1461
1462 /*
1463  * Visit the first child (need not be the first child as per the ordering
1464  * of the cgroup list, since we track last_scanned_child) of @mem and use
1465  * that to reclaim free pages from.
1466  */
1467 static struct mem_cgroup *
1468 mem_cgroup_select_victim(struct mem_cgroup *root_mem)
1469 {
1470         struct mem_cgroup *ret = NULL;
1471         struct cgroup_subsys_state *css;
1472         int nextid, found;
1473
1474         if (!root_mem->use_hierarchy) {
1475                 css_get(&root_mem->css);
1476                 ret = root_mem;
1477         }
1478
1479         while (!ret) {
1480                 rcu_read_lock();
1481                 nextid = root_mem->last_scanned_child + 1;
1482                 css = css_get_next(&mem_cgroup_subsys, nextid, &root_mem->css,
1483                                    &found);
1484                 if (css && css_tryget(css))
1485                         ret = container_of(css, struct mem_cgroup, css);
1486
1487                 rcu_read_unlock();
1488                 /* Updates scanning parameter */
1489                 if (!css) {
1490                         /* this means start scan from ID:1 */
1491                         root_mem->last_scanned_child = 0;
1492                 } else
1493                         root_mem->last_scanned_child = found;
1494         }
1495
1496         return ret;
1497 }
1498
1499 /**
1500  * test_mem_cgroup_node_reclaimable
1501  * @mem: the target memcg
1502  * @nid: the node ID to be checked.
1503  * @noswap : specify true here if the user wants flle only information.
1504  *
1505  * This function returns whether the specified memcg contains any
1506  * reclaimable pages on a node. Returns true if there are any reclaimable
1507  * pages in the node.
1508  */
1509 static bool test_mem_cgroup_node_reclaimable(struct mem_cgroup *mem,
1510                 int nid, bool noswap)
1511 {
1512         if (mem_cgroup_node_nr_lru_pages(mem, nid, LRU_ALL_FILE))
1513                 return true;
1514         if (noswap || !total_swap_pages)
1515                 return false;
1516         if (mem_cgroup_node_nr_lru_pages(mem, nid, LRU_ALL_ANON))
1517                 return true;
1518         return false;
1519
1520 }
1521 #if MAX_NUMNODES > 1
1522
1523 /*
1524  * Always updating the nodemask is not very good - even if we have an empty
1525  * list or the wrong list here, we can start from some node and traverse all
1526  * nodes based on the zonelist. So update the list loosely once per 10 secs.
1527  *
1528  */
1529 static void mem_cgroup_may_update_nodemask(struct mem_cgroup *mem)
1530 {
1531         int nid;
1532         /*
1533          * numainfo_events > 0 means there was at least NUMAINFO_EVENTS_TARGET
1534          * pagein/pageout changes since the last update.
1535          */
1536         if (!atomic_read(&mem->numainfo_events))
1537                 return;
1538         if (atomic_inc_return(&mem->numainfo_updating) > 1)
1539                 return;
1540
1541         /* make a nodemask where this memcg uses memory from */
1542         mem->scan_nodes = node_states[N_HIGH_MEMORY];
1543
1544         for_each_node_mask(nid, node_states[N_HIGH_MEMORY]) {
1545
1546                 if (!test_mem_cgroup_node_reclaimable(mem, nid, false))
1547                         node_clear(nid, mem->scan_nodes);
1548         }
1549
1550         atomic_set(&mem->numainfo_events, 0);
1551         atomic_set(&mem->numainfo_updating, 0);
1552 }
1553
1554 /*
1555  * Selecting a node where we start reclaim from. Because what we need is just
1556  * reducing usage counter, start from anywhere is O,K. Considering
1557  * memory reclaim from current node, there are pros. and cons.
1558  *
1559  * Freeing memory from current node means freeing memory from a node which
1560  * we'll use or we've used. So, it may make LRU bad. And if several threads
1561  * hit limits, it will see a contention on a node. But freeing from remote
1562  * node means more costs for memory reclaim because of memory latency.
1563  *
1564  * Now, we use round-robin. Better algorithm is welcomed.
1565  */
1566 int mem_cgroup_select_victim_node(struct mem_cgroup *mem)
1567 {
1568         int node;
1569
1570         mem_cgroup_may_update_nodemask(mem);
1571         node = mem->last_scanned_node;
1572
1573         node = next_node(node, mem->scan_nodes);
1574         if (node == MAX_NUMNODES)
1575                 node = first_node(mem->scan_nodes);
1576         /*
1577          * We call this when we hit limit, not when pages are added to LRU.
1578          * No LRU may hold pages because all pages are UNEVICTABLE or
1579          * memcg is too small and all pages are not on LRU. In that case,
1580          * we use curret node.
1581          */
1582         if (unlikely(node == MAX_NUMNODES))
1583                 node = numa_node_id();
1584
1585         mem->last_scanned_node = node;
1586         return node;
1587 }
1588
1589 /*
1590  * Check all nodes whether it contains reclaimable pages or not.
1591  * For quick scan, we make use of scan_nodes. This will allow us to skip
1592  * unused nodes. But scan_nodes is lazily updated and may not cotain
1593  * enough new information. We need to do double check.
1594  */
1595 bool mem_cgroup_reclaimable(struct mem_cgroup *mem, bool noswap)
1596 {
1597         int nid;
1598
1599         /*
1600          * quick check...making use of scan_node.
1601          * We can skip unused nodes.
1602          */
1603         if (!nodes_empty(mem->scan_nodes)) {
1604                 for (nid = first_node(mem->scan_nodes);
1605                      nid < MAX_NUMNODES;
1606                      nid = next_node(nid, mem->scan_nodes)) {
1607
1608                         if (test_mem_cgroup_node_reclaimable(mem, nid, noswap))
1609                                 return true;
1610                 }
1611         }
1612         /*
1613          * Check rest of nodes.
1614          */
1615         for_each_node_state(nid, N_HIGH_MEMORY) {
1616                 if (node_isset(nid, mem->scan_nodes))
1617                         continue;
1618                 if (test_mem_cgroup_node_reclaimable(mem, nid, noswap))
1619                         return true;
1620         }
1621         return false;
1622 }
1623
1624 #else
1625 int mem_cgroup_select_victim_node(struct mem_cgroup *mem)
1626 {
1627         return 0;
1628 }
1629
1630 bool mem_cgroup_reclaimable(struct mem_cgroup *mem, bool noswap)
1631 {
1632         return test_mem_cgroup_node_reclaimable(mem, 0, noswap);
1633 }
1634 #endif
1635
1636 /*
1637  * Scan the hierarchy if needed to reclaim memory. We remember the last child
1638  * we reclaimed from, so that we don't end up penalizing one child extensively
1639  * based on its position in the children list.
1640  *
1641  * root_mem is the original ancestor that we've been reclaim from.
1642  *
1643  * We give up and return to the caller when we visit root_mem twice.
1644  * (other groups can be removed while we're walking....)
1645  *
1646  * If shrink==true, for avoiding to free too much, this returns immedieately.
1647  */
1648 static int mem_cgroup_hierarchical_reclaim(struct mem_cgroup *root_mem,
1649                                                 struct zone *zone,
1650                                                 gfp_t gfp_mask,
1651                                                 unsigned long reclaim_options,
1652                                                 unsigned long *total_scanned)
1653 {
1654         struct mem_cgroup *victim;
1655         int ret, total = 0;
1656         int loop = 0;
1657         bool noswap = reclaim_options & MEM_CGROUP_RECLAIM_NOSWAP;
1658         bool shrink = reclaim_options & MEM_CGROUP_RECLAIM_SHRINK;
1659         bool check_soft = reclaim_options & MEM_CGROUP_RECLAIM_SOFT;
1660         unsigned long excess;
1661         unsigned long nr_scanned;
1662
1663         excess = res_counter_soft_limit_excess(&root_mem->res) >> PAGE_SHIFT;
1664
1665         /* If memsw_is_minimum==1, swap-out is of-no-use. */
1666         if (!check_soft && !shrink && root_mem->memsw_is_minimum)
1667                 noswap = true;
1668
1669         while (1) {
1670                 victim = mem_cgroup_select_victim(root_mem);
1671                 if (victim == root_mem) {
1672                         loop++;
1673                         /*
1674                          * We are not draining per cpu cached charges during
1675                          * soft limit reclaim  because global reclaim doesn't
1676                          * care about charges. It tries to free some memory and
1677                          * charges will not give any.
1678                          */
1679                         if (!check_soft && loop >= 1)
1680                                 drain_all_stock_async(root_mem);
1681                         if (loop >= 2) {
1682                                 /*
1683                                  * If we have not been able to reclaim
1684                                  * anything, it might because there are
1685                                  * no reclaimable pages under this hierarchy
1686                                  */
1687                                 if (!check_soft || !total) {
1688                                         css_put(&victim->css);
1689                                         break;
1690                                 }
1691                                 /*
1692                                  * We want to do more targeted reclaim.
1693                                  * excess >> 2 is not to excessive so as to
1694                                  * reclaim too much, nor too less that we keep
1695                                  * coming back to reclaim from this cgroup
1696                                  */
1697                                 if (total >= (excess >> 2) ||
1698                                         (loop > MEM_CGROUP_MAX_RECLAIM_LOOPS)) {
1699                                         css_put(&victim->css);
1700                                         break;
1701                                 }
1702                         }
1703                 }
1704                 if (!mem_cgroup_reclaimable(victim, noswap)) {
1705                         /* this cgroup's local usage == 0 */
1706                         css_put(&victim->css);
1707                         continue;
1708                 }
1709                 /* we use swappiness of local cgroup */
1710                 if (check_soft) {
1711                         ret = mem_cgroup_shrink_node_zone(victim, gfp_mask,
1712                                 noswap, zone, &nr_scanned);
1713                         *total_scanned += nr_scanned;
1714                 } else
1715                         ret = try_to_free_mem_cgroup_pages(victim, gfp_mask,
1716                                                 noswap);
1717                 css_put(&victim->css);
1718                 /*
1719                  * At shrinking usage, we can't check we should stop here or
1720                  * reclaim more. It's depends on callers. last_scanned_child
1721                  * will work enough for keeping fairness under tree.
1722                  */
1723                 if (shrink)
1724                         return ret;
1725                 total += ret;
1726                 if (check_soft) {
1727                         if (!res_counter_soft_limit_excess(&root_mem->res))
1728                                 return total;
1729                 } else if (mem_cgroup_margin(root_mem))
1730                         return total;
1731         }
1732         return total;
1733 }
1734
1735 /*
1736  * Check OOM-Killer is already running under our hierarchy.
1737  * If someone is running, return false.
1738  * Has to be called with memcg_oom_lock
1739  */
1740 static bool mem_cgroup_oom_lock(struct mem_cgroup *mem)
1741 {
1742         struct mem_cgroup *iter, *failed = NULL;
1743         bool cond = true;
1744
1745         for_each_mem_cgroup_tree_cond(iter, mem, cond) {
1746                 if (iter->oom_lock) {
1747                         /*
1748                          * this subtree of our hierarchy is already locked
1749                          * so we cannot give a lock.
1750                          */
1751                         failed = iter;
1752                         cond = false;
1753                 } else
1754                         iter->oom_lock = true;
1755         }
1756
1757         if (!failed)
1758                 return true;
1759
1760         /*
1761          * OK, we failed to lock the whole subtree so we have to clean up
1762          * what we set up to the failing subtree
1763          */
1764         cond = true;
1765         for_each_mem_cgroup_tree_cond(iter, mem, cond) {
1766                 if (iter == failed) {
1767                         cond = false;
1768                         continue;
1769                 }
1770                 iter->oom_lock = false;
1771         }
1772         return false;
1773 }
1774
1775 /*
1776  * Has to be called with memcg_oom_lock
1777  */
1778 static int mem_cgroup_oom_unlock(struct mem_cgroup *mem)
1779 {
1780         struct mem_cgroup *iter;
1781
1782         for_each_mem_cgroup_tree(iter, mem)
1783                 iter->oom_lock = false;
1784         return 0;
1785 }
1786
1787 static void mem_cgroup_mark_under_oom(struct mem_cgroup *mem)
1788 {
1789         struct mem_cgroup *iter;
1790
1791         for_each_mem_cgroup_tree(iter, mem)
1792                 atomic_inc(&iter->under_oom);
1793 }
1794
1795 static void mem_cgroup_unmark_under_oom(struct mem_cgroup *mem)
1796 {
1797         struct mem_cgroup *iter;
1798
1799         /*
1800          * When a new child is created while the hierarchy is under oom,
1801          * mem_cgroup_oom_lock() may not be called. We have to use
1802          * atomic_add_unless() here.
1803          */
1804         for_each_mem_cgroup_tree(iter, mem)
1805                 atomic_add_unless(&iter->under_oom, -1, 0);
1806 }
1807
1808 static DEFINE_SPINLOCK(memcg_oom_lock);
1809 static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq);
1810
1811 struct oom_wait_info {
1812         struct mem_cgroup *mem;
1813         wait_queue_t    wait;
1814 };
1815
1816 static int memcg_oom_wake_function(wait_queue_t *wait,
1817         unsigned mode, int sync, void *arg)
1818 {
1819         struct mem_cgroup *wake_mem = (struct mem_cgroup *)arg,
1820                           *oom_wait_mem;
1821         struct oom_wait_info *oom_wait_info;
1822
1823         oom_wait_info = container_of(wait, struct oom_wait_info, wait);
1824         oom_wait_mem = oom_wait_info->mem;
1825
1826         /*
1827          * Both of oom_wait_info->mem and wake_mem are stable under us.
1828          * Then we can use css_is_ancestor without taking care of RCU.
1829          */
1830         if (!mem_cgroup_same_or_subtree(oom_wait_mem, wake_mem)
1831                         && !mem_cgroup_same_or_subtree(wake_mem, oom_wait_mem))
1832                 return 0;
1833         return autoremove_wake_function(wait, mode, sync, arg);
1834 }
1835
1836 static void memcg_wakeup_oom(struct mem_cgroup *mem)
1837 {
1838         /* for filtering, pass "mem" as argument. */
1839         __wake_up(&memcg_oom_waitq, TASK_NORMAL, 0, mem);
1840 }
1841
1842 static void memcg_oom_recover(struct mem_cgroup *mem)
1843 {
1844         if (mem && atomic_read(&mem->under_oom))
1845                 memcg_wakeup_oom(mem);
1846 }
1847
1848 /*
1849  * try to call OOM killer. returns false if we should exit memory-reclaim loop.
1850  */
1851 bool mem_cgroup_handle_oom(struct mem_cgroup *mem, gfp_t mask)
1852 {
1853         struct oom_wait_info owait;
1854         bool locked, need_to_kill;
1855
1856         owait.mem = mem;
1857         owait.wait.flags = 0;
1858         owait.wait.func = memcg_oom_wake_function;
1859         owait.wait.private = current;
1860         INIT_LIST_HEAD(&owait.wait.task_list);
1861         need_to_kill = true;
1862         mem_cgroup_mark_under_oom(mem);
1863
1864         /* At first, try to OOM lock hierarchy under mem.*/
1865         spin_lock(&memcg_oom_lock);
1866         locked = mem_cgroup_oom_lock(mem);
1867         /*
1868          * Even if signal_pending(), we can't quit charge() loop without
1869          * accounting. So, UNINTERRUPTIBLE is appropriate. But SIGKILL
1870          * under OOM is always welcomed, use TASK_KILLABLE here.
1871          */
1872         prepare_to_wait(&memcg_oom_waitq, &owait.wait, TASK_KILLABLE);
1873         if (!locked || mem->oom_kill_disable)
1874                 need_to_kill = false;
1875         if (locked)
1876                 mem_cgroup_oom_notify(mem);
1877         spin_unlock(&memcg_oom_lock);
1878
1879         if (need_to_kill) {
1880                 finish_wait(&memcg_oom_waitq, &owait.wait);
1881                 mem_cgroup_out_of_memory(mem, mask);
1882         } else {
1883                 schedule();
1884                 finish_wait(&memcg_oom_waitq, &owait.wait);
1885         }
1886         spin_lock(&memcg_oom_lock);
1887         if (locked)
1888                 mem_cgroup_oom_unlock(mem);
1889         memcg_wakeup_oom(mem);
1890         spin_unlock(&memcg_oom_lock);
1891
1892         mem_cgroup_unmark_under_oom(mem);
1893
1894         if (test_thread_flag(TIF_MEMDIE) || fatal_signal_pending(current))
1895                 return false;
1896         /* Give chance to dying process */
1897         schedule_timeout(1);
1898         return true;
1899 }
1900
1901 /*
1902  * Currently used to update mapped file statistics, but the routine can be
1903  * generalized to update other statistics as well.
1904  *
1905  * Notes: Race condition
1906  *
1907  * We usually use page_cgroup_lock() for accessing page_cgroup member but
1908  * it tends to be costly. But considering some conditions, we doesn't need
1909  * to do so _always_.
1910  *
1911  * Considering "charge", lock_page_cgroup() is not required because all
1912  * file-stat operations happen after a page is attached to radix-tree. There
1913  * are no race with "charge".
1914  *
1915  * Considering "uncharge", we know that memcg doesn't clear pc->mem_cgroup
1916  * at "uncharge" intentionally. So, we always see valid pc->mem_cgroup even
1917  * if there are race with "uncharge". Statistics itself is properly handled
1918  * by flags.
1919  *
1920  * Considering "move", this is an only case we see a race. To make the race
1921  * small, we check MEM_CGROUP_ON_MOVE percpu value and detect there are
1922  * possibility of race condition. If there is, we take a lock.
1923  */
1924
1925 void mem_cgroup_update_page_stat(struct page *page,
1926                                  enum mem_cgroup_page_stat_item idx, int val)
1927 {
1928         struct mem_cgroup *mem;
1929         struct page_cgroup *pc = lookup_page_cgroup(page);
1930         bool need_unlock = false;
1931         unsigned long uninitialized_var(flags);
1932
1933         if (unlikely(!pc))
1934                 return;
1935
1936         rcu_read_lock();
1937         mem = pc->mem_cgroup;
1938         if (unlikely(!mem || !PageCgroupUsed(pc)))
1939                 goto out;
1940         /* pc->mem_cgroup is unstable ? */
1941         if (unlikely(mem_cgroup_stealed(mem)) || PageTransHuge(page)) {
1942                 /* take a lock against to access pc->mem_cgroup */
1943                 move_lock_page_cgroup(pc, &flags);
1944                 need_unlock = true;
1945                 mem = pc->mem_cgroup;
1946                 if (!mem || !PageCgroupUsed(pc))
1947                         goto out;
1948         }
1949
1950         switch (idx) {
1951         case MEMCG_NR_FILE_MAPPED:
1952                 if (val > 0)
1953                         SetPageCgroupFileMapped(pc);
1954                 else if (!page_mapped(page))
1955                         ClearPageCgroupFileMapped(pc);
1956                 idx = MEM_CGROUP_STAT_FILE_MAPPED;
1957                 break;
1958         default:
1959                 BUG();
1960         }
1961
1962         this_cpu_add(mem->stat->count[idx], val);
1963
1964 out:
1965         if (unlikely(need_unlock))
1966                 move_unlock_page_cgroup(pc, &flags);
1967         rcu_read_unlock();
1968         return;
1969 }
1970 EXPORT_SYMBOL(mem_cgroup_update_page_stat);
1971
1972 /*
1973  * size of first charge trial. "32" comes from vmscan.c's magic value.
1974  * TODO: maybe necessary to use big numbers in big irons.
1975  */
1976 #define CHARGE_BATCH    32U
1977 struct memcg_stock_pcp {
1978         struct mem_cgroup *cached; /* this never be root cgroup */
1979         unsigned int nr_pages;
1980         struct work_struct work;
1981         unsigned long flags;
1982 #define FLUSHING_CACHED_CHARGE  (0)
1983 };
1984 static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock);
1985 static DEFINE_MUTEX(percpu_charge_mutex);
1986
1987 /*
1988  * Try to consume stocked charge on this cpu. If success, one page is consumed
1989  * from local stock and true is returned. If the stock is 0 or charges from a
1990  * cgroup which is not current target, returns false. This stock will be
1991  * refilled.
1992  */
1993 static bool consume_stock(struct mem_cgroup *mem)
1994 {
1995         struct memcg_stock_pcp *stock;
1996         bool ret = true;
1997
1998         stock = &get_cpu_var(memcg_stock);
1999         if (mem == stock->cached && stock->nr_pages)
2000                 stock->nr_pages--;
2001         else /* need to call res_counter_charge */
2002                 ret = false;
2003         put_cpu_var(memcg_stock);
2004         return ret;
2005 }
2006
2007 /*
2008  * Returns stocks cached in percpu to res_counter and reset cached information.
2009  */
2010 static void drain_stock(struct memcg_stock_pcp *stock)
2011 {
2012         struct mem_cgroup *old = stock->cached;
2013
2014         if (stock->nr_pages) {
2015                 unsigned long bytes = stock->nr_pages * PAGE_SIZE;
2016
2017                 res_counter_uncharge(&old->res, bytes);
2018                 if (do_swap_account)
2019                         res_counter_uncharge(&old->memsw, bytes);
2020                 stock->nr_pages = 0;
2021         }
2022         stock->cached = NULL;
2023 }
2024
2025 /*
2026  * This must be called under preempt disabled or must be called by
2027  * a thread which is pinned to local cpu.
2028  */
2029 static void drain_local_stock(struct work_struct *dummy)
2030 {
2031         struct memcg_stock_pcp *stock = &__get_cpu_var(memcg_stock);
2032         drain_stock(stock);
2033         clear_bit(FLUSHING_CACHED_CHARGE, &stock->flags);
2034 }
2035
2036 /*
2037  * Cache charges(val) which is from res_counter, to local per_cpu area.
2038  * This will be consumed by consume_stock() function, later.
2039  */
2040 static void refill_stock(struct mem_cgroup *mem, unsigned int nr_pages)
2041 {
2042         struct memcg_stock_pcp *stock = &get_cpu_var(memcg_stock);
2043
2044         if (stock->cached != mem) { /* reset if necessary */
2045                 drain_stock(stock);
2046                 stock->cached = mem;
2047         }
2048         stock->nr_pages += nr_pages;
2049         put_cpu_var(memcg_stock);
2050 }
2051
2052 /*
2053  * Drains all per-CPU charge caches for given root_mem resp. subtree
2054  * of the hierarchy under it. sync flag says whether we should block
2055  * until the work is done.
2056  */
2057 static void drain_all_stock(struct mem_cgroup *root_mem, bool sync)
2058 {
2059         int cpu, curcpu;
2060
2061         /* Notify other cpus that system-wide "drain" is running */
2062         get_online_cpus();
2063         curcpu = get_cpu();
2064         for_each_online_cpu(cpu) {
2065                 struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
2066                 struct mem_cgroup *mem;
2067
2068                 mem = stock->cached;
2069                 if (!mem || !stock->nr_pages)
2070                         continue;
2071                 if (!mem_cgroup_same_or_subtree(root_mem, mem))
2072                         continue;
2073                 if (!test_and_set_bit(FLUSHING_CACHED_CHARGE, &stock->flags)) {
2074                         if (cpu == curcpu)
2075                                 drain_local_stock(&stock->work);
2076                         else
2077                                 schedule_work_on(cpu, &stock->work);
2078                 }
2079         }
2080         put_cpu();
2081
2082         if (!sync)
2083                 goto out;
2084
2085         for_each_online_cpu(cpu) {
2086                 struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
2087                 if (test_bit(FLUSHING_CACHED_CHARGE, &stock->flags))
2088                         flush_work(&stock->work);
2089         }
2090 out:
2091         put_online_cpus();
2092 }
2093
2094 /*
2095  * Tries to drain stocked charges in other cpus. This function is asynchronous
2096  * and just put a work per cpu for draining localy on each cpu. Caller can
2097  * expects some charges will be back to res_counter later but cannot wait for
2098  * it.
2099  */
2100 static void drain_all_stock_async(struct mem_cgroup *root_mem)
2101 {
2102         /*
2103          * If someone calls draining, avoid adding more kworker runs.
2104          */
2105         if (!mutex_trylock(&percpu_charge_mutex))
2106                 return;
2107         drain_all_stock(root_mem, false);
2108         mutex_unlock(&percpu_charge_mutex);
2109 }
2110
2111 /* This is a synchronous drain interface. */
2112 static void drain_all_stock_sync(struct mem_cgroup *root_mem)
2113 {
2114         /* called when force_empty is called */
2115         mutex_lock(&percpu_charge_mutex);
2116         drain_all_stock(root_mem, true);
2117         mutex_unlock(&percpu_charge_mutex);
2118 }
2119
2120 /*
2121  * This function drains percpu counter value from DEAD cpu and
2122  * move it to local cpu. Note that this function can be preempted.
2123  */
2124 static void mem_cgroup_drain_pcp_counter(struct mem_cgroup *mem, int cpu)
2125 {
2126         int i;
2127
2128         spin_lock(&mem->pcp_counter_lock);
2129         for (i = 0; i < MEM_CGROUP_STAT_DATA; i++) {
2130                 long x = per_cpu(mem->stat->count[i], cpu);
2131
2132                 per_cpu(mem->stat->count[i], cpu) = 0;
2133                 mem->nocpu_base.count[i] += x;
2134         }
2135         for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++) {
2136                 unsigned long x = per_cpu(mem->stat->events[i], cpu);
2137
2138                 per_cpu(mem->stat->events[i], cpu) = 0;
2139                 mem->nocpu_base.events[i] += x;
2140         }
2141         /* need to clear ON_MOVE value, works as a kind of lock. */
2142         per_cpu(mem->stat->count[MEM_CGROUP_ON_MOVE], cpu) = 0;
2143         spin_unlock(&mem->pcp_counter_lock);
2144 }
2145
2146 static void synchronize_mem_cgroup_on_move(struct mem_cgroup *mem, int cpu)
2147 {
2148         int idx = MEM_CGROUP_ON_MOVE;
2149
2150         spin_lock(&mem->pcp_counter_lock);
2151         per_cpu(mem->stat->count[idx], cpu) = mem->nocpu_base.count[idx];
2152         spin_unlock(&mem->pcp_counter_lock);
2153 }
2154
2155 static int __cpuinit memcg_cpu_hotplug_callback(struct notifier_block *nb,
2156                                         unsigned long action,
2157                                         void *hcpu)
2158 {
2159         int cpu = (unsigned long)hcpu;
2160         struct memcg_stock_pcp *stock;
2161         struct mem_cgroup *iter;
2162
2163         if ((action == CPU_ONLINE)) {
2164                 for_each_mem_cgroup_all(iter)
2165                         synchronize_mem_cgroup_on_move(iter, cpu);
2166                 return NOTIFY_OK;
2167         }
2168
2169         if ((action != CPU_DEAD) || action != CPU_DEAD_FROZEN)
2170                 return NOTIFY_OK;
2171
2172         for_each_mem_cgroup_all(iter)
2173                 mem_cgroup_drain_pcp_counter(iter, cpu);
2174
2175         stock = &per_cpu(memcg_stock, cpu);
2176         drain_stock(stock);
2177         return NOTIFY_OK;
2178 }
2179
2180
2181 /* See __mem_cgroup_try_charge() for details */
2182 enum {
2183         CHARGE_OK,              /* success */
2184         CHARGE_RETRY,           /* need to retry but retry is not bad */
2185         CHARGE_NOMEM,           /* we can't do more. return -ENOMEM */
2186         CHARGE_WOULDBLOCK,      /* GFP_WAIT wasn't set and no enough res. */
2187         CHARGE_OOM_DIE,         /* the current is killed because of OOM */
2188 };
2189
2190 static int mem_cgroup_do_charge(struct mem_cgroup *mem, gfp_t gfp_mask,
2191                                 unsigned int nr_pages, bool oom_check)
2192 {
2193         unsigned long csize = nr_pages * PAGE_SIZE;
2194         struct mem_cgroup *mem_over_limit;
2195         struct res_counter *fail_res;
2196         unsigned long flags = 0;
2197         int ret;
2198
2199         ret = res_counter_charge(&mem->res, csize, &fail_res);
2200
2201         if (likely(!ret)) {
2202                 if (!do_swap_account)
2203                         return CHARGE_OK;
2204                 ret = res_counter_charge(&mem->memsw, csize, &fail_res);
2205                 if (likely(!ret))
2206                         return CHARGE_OK;
2207
2208                 res_counter_uncharge(&mem->res, csize);
2209                 mem_over_limit = mem_cgroup_from_res_counter(fail_res, memsw);
2210                 flags |= MEM_CGROUP_RECLAIM_NOSWAP;
2211         } else
2212                 mem_over_limit = mem_cgroup_from_res_counter(fail_res, res);
2213         /*
2214          * nr_pages can be either a huge page (HPAGE_PMD_NR), a batch
2215          * of regular pages (CHARGE_BATCH), or a single regular page (1).
2216          *
2217          * Never reclaim on behalf of optional batching, retry with a
2218          * single page instead.
2219          */
2220         if (nr_pages == CHARGE_BATCH)
2221                 return CHARGE_RETRY;
2222
2223         if (!(gfp_mask & __GFP_WAIT))
2224                 return CHARGE_WOULDBLOCK;
2225
2226         ret = mem_cgroup_hierarchical_reclaim(mem_over_limit, NULL,
2227                                               gfp_mask, flags, NULL);
2228         if (mem_cgroup_margin(mem_over_limit) >= nr_pages)
2229                 return CHARGE_RETRY;
2230         /*
2231          * Even though the limit is exceeded at this point, reclaim
2232          * may have been able to free some pages.  Retry the charge
2233          * before killing the task.
2234          *
2235          * Only for regular pages, though: huge pages are rather
2236          * unlikely to succeed so close to the limit, and we fall back
2237          * to regular pages anyway in case of failure.
2238          */
2239         if (nr_pages == 1 && ret)
2240                 return CHARGE_RETRY;
2241
2242         /*
2243          * At task move, charge accounts can be doubly counted. So, it's
2244          * better to wait until the end of task_move if something is going on.
2245          */
2246         if (mem_cgroup_wait_acct_move(mem_over_limit))
2247                 return CHARGE_RETRY;
2248
2249         /* If we don't need to call oom-killer at el, return immediately */
2250         if (!oom_check)
2251                 return CHARGE_NOMEM;
2252         /* check OOM */
2253         if (!mem_cgroup_handle_oom(mem_over_limit, gfp_mask))
2254                 return CHARGE_OOM_DIE;
2255
2256         return CHARGE_RETRY;
2257 }
2258
2259 /*
2260  * Unlike exported interface, "oom" parameter is added. if oom==true,
2261  * oom-killer can be invoked.
2262  */
2263 static int __mem_cgroup_try_charge(struct mm_struct *mm,
2264                                    gfp_t gfp_mask,
2265                                    unsigned int nr_pages,
2266                                    struct mem_cgroup **memcg,
2267                                    bool oom)
2268 {
2269         unsigned int batch = max(CHARGE_BATCH, nr_pages);
2270         int nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES;
2271         struct mem_cgroup *mem = NULL;
2272         int ret;
2273
2274         /*
2275          * Unlike gloval-vm's OOM-kill, we're not in memory shortage
2276          * in system level. So, allow to go ahead dying process in addition to
2277          * MEMDIE process.
2278          */
2279         if (unlikely(test_thread_flag(TIF_MEMDIE)
2280                      || fatal_signal_pending(current)))
2281                 goto bypass;
2282
2283         /*
2284          * We always charge the cgroup the mm_struct belongs to.
2285          * The mm_struct's mem_cgroup changes on task migration if the
2286          * thread group leader migrates. It's possible that mm is not
2287          * set, if so charge the init_mm (happens for pagecache usage).
2288          */
2289         if (!*memcg && !mm)
2290                 goto bypass;
2291 again:
2292         if (*memcg) { /* css should be a valid one */
2293                 mem = *memcg;
2294                 VM_BUG_ON(css_is_removed(&mem->css));
2295                 if (mem_cgroup_is_root(mem))
2296                         goto done;
2297                 if (nr_pages == 1 && consume_stock(mem))
2298                         goto done;
2299                 css_get(&mem->css);
2300         } else {
2301                 struct task_struct *p;
2302
2303                 rcu_read_lock();
2304                 p = rcu_dereference(mm->owner);
2305                 /*
2306                  * Because we don't have task_lock(), "p" can exit.
2307                  * In that case, "mem" can point to root or p can be NULL with
2308                  * race with swapoff. Then, we have small risk of mis-accouning.
2309                  * But such kind of mis-account by race always happens because
2310                  * we don't have cgroup_mutex(). It's overkill and we allo that
2311                  * small race, here.
2312                  * (*) swapoff at el will charge against mm-struct not against
2313                  * task-struct. So, mm->owner can be NULL.
2314                  */
2315                 mem = mem_cgroup_from_task(p);
2316                 if (!mem || mem_cgroup_is_root(mem)) {
2317                         rcu_read_unlock();
2318                         goto done;
2319                 }
2320                 if (nr_pages == 1 && consume_stock(mem)) {
2321                         /*
2322                          * It seems dagerous to access memcg without css_get().
2323                          * But considering how consume_stok works, it's not
2324                          * necessary. If consume_stock success, some charges
2325                          * from this memcg are cached on this cpu. So, we
2326                          * don't need to call css_get()/css_tryget() before
2327                          * calling consume_stock().
2328                          */
2329                         rcu_read_unlock();
2330                         goto done;
2331                 }
2332                 /* after here, we may be blocked. we need to get refcnt */
2333                 if (!css_tryget(&mem->css)) {
2334                         rcu_read_unlock();
2335                         goto again;
2336                 }
2337                 rcu_read_unlock();
2338         }
2339
2340         do {
2341                 bool oom_check;
2342
2343                 /* If killed, bypass charge */
2344                 if (fatal_signal_pending(current)) {
2345                         css_put(&mem->css);
2346                         goto bypass;
2347                 }
2348
2349                 oom_check = false;
2350                 if (oom && !nr_oom_retries) {
2351                         oom_check = true;
2352                         nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES;
2353                 }
2354
2355                 ret = mem_cgroup_do_charge(mem, gfp_mask, batch, oom_check);
2356                 switch (ret) {
2357                 case CHARGE_OK:
2358                         break;
2359                 case CHARGE_RETRY: /* not in OOM situation but retry */
2360                         batch = nr_pages;
2361                         css_put(&mem->css);
2362                         mem = NULL;
2363                         goto again;
2364                 case CHARGE_WOULDBLOCK: /* !__GFP_WAIT */
2365                         css_put(&mem->css);
2366                         goto nomem;
2367                 case CHARGE_NOMEM: /* OOM routine works */
2368                         if (!oom) {
2369                                 css_put(&mem->css);
2370                                 goto nomem;
2371                         }
2372                         /* If oom, we never return -ENOMEM */
2373                         nr_oom_retries--;
2374                         break;
2375                 case CHARGE_OOM_DIE: /* Killed by OOM Killer */
2376                         css_put(&mem->css);
2377                         goto bypass;
2378                 }
2379         } while (ret != CHARGE_OK);
2380
2381         if (batch > nr_pages)
2382                 refill_stock(mem, batch - nr_pages);
2383         css_put(&mem->css);
2384 done:
2385         *memcg = mem;
2386         return 0;
2387 nomem:
2388         *memcg = NULL;
2389         return -ENOMEM;
2390 bypass:
2391         *memcg = NULL;
2392         return 0;
2393 }
2394
2395 /*
2396  * Somemtimes we have to undo a charge we got by try_charge().
2397  * This function is for that and do uncharge, put css's refcnt.
2398  * gotten by try_charge().
2399  */
2400 static void __mem_cgroup_cancel_charge(struct mem_cgroup *mem,
2401                                        unsigned int nr_pages)
2402 {
2403         if (!mem_cgroup_is_root(mem)) {
2404                 unsigned long bytes = nr_pages * PAGE_SIZE;
2405
2406                 res_counter_uncharge(&mem->res, bytes);
2407                 if (do_swap_account)
2408                         res_counter_uncharge(&mem->memsw, bytes);
2409         }
2410 }
2411
2412 /*
2413  * A helper function to get mem_cgroup from ID. must be called under
2414  * rcu_read_lock(). The caller must check css_is_removed() or some if
2415  * it's concern. (dropping refcnt from swap can be called against removed
2416  * memcg.)
2417  */
2418 static struct mem_cgroup *mem_cgroup_lookup(unsigned short id)
2419 {
2420         struct cgroup_subsys_state *css;
2421
2422         /* ID 0 is unused ID */
2423         if (!id)
2424                 return NULL;
2425         css = css_lookup(&mem_cgroup_subsys, id);
2426         if (!css)
2427                 return NULL;
2428         return container_of(css, struct mem_cgroup, css);
2429 }
2430
2431 struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page)
2432 {
2433         struct mem_cgroup *mem = NULL;
2434         struct page_cgroup *pc;
2435         unsigned short id;
2436         swp_entry_t ent;
2437
2438         VM_BUG_ON(!PageLocked(page));
2439
2440         pc = lookup_page_cgroup(page);
2441         lock_page_cgroup(pc);
2442         if (PageCgroupUsed(pc)) {
2443                 mem = pc->mem_cgroup;
2444                 if (mem && !css_tryget(&mem->css))
2445                         mem = NULL;
2446         } else if (PageSwapCache(page)) {
2447                 ent.val = page_private(page);
2448                 id = lookup_swap_cgroup(ent);
2449                 rcu_read_lock();
2450                 mem = mem_cgroup_lookup(id);
2451                 if (mem && !css_tryget(&mem->css))
2452                         mem = NULL;
2453                 rcu_read_unlock();
2454         }
2455         unlock_page_cgroup(pc);
2456         return mem;
2457 }
2458
2459 static void __mem_cgroup_commit_charge(struct mem_cgroup *mem,
2460                                        struct page *page,
2461                                        unsigned int nr_pages,
2462                                        struct page_cgroup *pc,
2463                                        enum charge_type ctype)
2464 {
2465         lock_page_cgroup(pc);
2466         if (unlikely(PageCgroupUsed(pc))) {
2467                 unlock_page_cgroup(pc);
2468                 __mem_cgroup_cancel_charge(mem, nr_pages);
2469                 return;
2470         }
2471         /*
2472          * we don't need page_cgroup_lock about tail pages, becase they are not
2473          * accessed by any other context at this point.
2474          */
2475         pc->mem_cgroup = mem;
2476         /*
2477          * We access a page_cgroup asynchronously without lock_page_cgroup().
2478          * Especially when a page_cgroup is taken from a page, pc->mem_cgroup
2479          * is accessed after testing USED bit. To make pc->mem_cgroup visible
2480          * before USED bit, we need memory barrier here.
2481          * See mem_cgroup_add_lru_list(), etc.
2482          */
2483         smp_wmb();
2484         switch (ctype) {
2485         case MEM_CGROUP_CHARGE_TYPE_CACHE:
2486         case MEM_CGROUP_CHARGE_TYPE_SHMEM:
2487                 SetPageCgroupCache(pc);
2488                 SetPageCgroupUsed(pc);
2489                 break;
2490         case MEM_CGROUP_CHARGE_TYPE_MAPPED:
2491                 ClearPageCgroupCache(pc);
2492                 SetPageCgroupUsed(pc);
2493                 break;
2494         default:
2495                 break;
2496         }
2497
2498         mem_cgroup_charge_statistics(mem, PageCgroupCache(pc), nr_pages);
2499         unlock_page_cgroup(pc);
2500         /*
2501          * "charge_statistics" updated event counter. Then, check it.
2502          * Insert ancestor (and ancestor's ancestors), to softlimit RB-tree.
2503          * if they exceeds softlimit.
2504          */
2505         memcg_check_events(mem, page);
2506 }
2507
2508 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
2509
2510 #define PCGF_NOCOPY_AT_SPLIT ((1 << PCG_LOCK) | (1 << PCG_MOVE_LOCK) |\
2511                         (1 << PCG_ACCT_LRU) | (1 << PCG_MIGRATION))
2512 /*
2513  * Because tail pages are not marked as "used", set it. We're under
2514  * zone->lru_lock, 'splitting on pmd' and compund_lock.
2515  */
2516 void mem_cgroup_split_huge_fixup(struct page *head, struct page *tail)
2517 {
2518         struct page_cgroup *head_pc = lookup_page_cgroup(head);
2519         struct page_cgroup *tail_pc = lookup_page_cgroup(tail);
2520         unsigned long flags;
2521
2522         if (mem_cgroup_disabled())
2523                 return;
2524         /*
2525          * We have no races with charge/uncharge but will have races with
2526          * page state accounting.
2527          */
2528         move_lock_page_cgroup(head_pc, &flags);
2529
2530         tail_pc->mem_cgroup = head_pc->mem_cgroup;
2531         smp_wmb(); /* see __commit_charge() */
2532         if (PageCgroupAcctLRU(head_pc)) {
2533                 enum lru_list lru;
2534                 struct mem_cgroup_per_zone *mz;
2535
2536                 /*
2537                  * LRU flags cannot be copied because we need to add tail
2538                  *.page to LRU by generic call and our hook will be called.
2539                  * We hold lru_lock, then, reduce counter directly.
2540                  */
2541                 lru = page_lru(head);
2542                 mz = page_cgroup_zoneinfo(head_pc->mem_cgroup, head);
2543                 MEM_CGROUP_ZSTAT(mz, lru) -= 1;
2544         }
2545         tail_pc->flags = head_pc->flags & ~PCGF_NOCOPY_AT_SPLIT;
2546         move_unlock_page_cgroup(head_pc, &flags);
2547 }
2548 #endif
2549
2550 /**
2551  * mem_cgroup_move_account - move account of the page
2552  * @page: the page
2553  * @nr_pages: number of regular pages (>1 for huge pages)
2554  * @pc: page_cgroup of the page.
2555  * @from: mem_cgroup which the page is moved from.
2556  * @to: mem_cgroup which the page is moved to. @from != @to.
2557  * @uncharge: whether we should call uncharge and css_put against @from.
2558  *
2559  * The caller must confirm following.
2560  * - page is not on LRU (isolate_page() is useful.)
2561  * - compound_lock is held when nr_pages > 1
2562  *
2563  * This function doesn't do "charge" nor css_get to new cgroup. It should be
2564  * done by a caller(__mem_cgroup_try_charge would be useful). If @uncharge is
2565  * true, this function does "uncharge" from old cgroup, but it doesn't if
2566  * @uncharge is false, so a caller should do "uncharge".
2567  */
2568 static int mem_cgroup_move_account(struct page *page,
2569                                    unsigned int nr_pages,
2570                                    struct page_cgroup *pc,
2571                                    struct mem_cgroup *from,
2572                                    struct mem_cgroup *to,
2573                                    bool uncharge)
2574 {
2575         unsigned long flags;
2576         int ret;
2577
2578         VM_BUG_ON(from == to);
2579         VM_BUG_ON(PageLRU(page));
2580         /*
2581          * The page is isolated from LRU. So, collapse function
2582          * will not handle this page. But page splitting can happen.
2583          * Do this check under compound_page_lock(). The caller should
2584          * hold it.
2585          */
2586         ret = -EBUSY;
2587         if (nr_pages > 1 && !PageTransHuge(page))
2588                 goto out;
2589
2590         lock_page_cgroup(pc);
2591
2592         ret = -EINVAL;
2593         if (!PageCgroupUsed(pc) || pc->mem_cgroup != from)
2594                 goto unlock;
2595
2596         move_lock_page_cgroup(pc, &flags);
2597
2598         if (PageCgroupFileMapped(pc)) {
2599                 /* Update mapped_file data for mem_cgroup */
2600                 preempt_disable();
2601                 __this_cpu_dec(from->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]);
2602                 __this_cpu_inc(to->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]);
2603                 preempt_enable();
2604         }
2605         mem_cgroup_charge_statistics(from, PageCgroupCache(pc), -nr_pages);
2606         if (uncharge)
2607                 /* This is not "cancel", but cancel_charge does all we need. */
2608                 __mem_cgroup_cancel_charge(from, nr_pages);
2609
2610         /* caller should have done css_get */
2611         pc->mem_cgroup = to;
2612         mem_cgroup_charge_statistics(to, PageCgroupCache(pc), nr_pages);
2613         /*
2614          * We charges against "to" which may not have any tasks. Then, "to"
2615          * can be under rmdir(). But in current implementation, caller of
2616          * this function is just force_empty() and move charge, so it's
2617          * guaranteed that "to" is never removed. So, we don't check rmdir
2618          * status here.
2619          */
2620         move_unlock_page_cgroup(pc, &flags);
2621         ret = 0;
2622 unlock:
2623         unlock_page_cgroup(pc);
2624         /*
2625          * check events
2626          */
2627         memcg_check_events(to, page);
2628         memcg_check_events(from, page);
2629 out:
2630         return ret;
2631 }
2632
2633 /*
2634  * move charges to its parent.
2635  */
2636
2637 static int mem_cgroup_move_parent(struct page *page,
2638                                   struct page_cgroup *pc,
2639                                   struct mem_cgroup *child,
2640                                   gfp_t gfp_mask)
2641 {
2642         struct cgroup *cg = child->css.cgroup;
2643         struct cgroup *pcg = cg->parent;
2644         struct mem_cgroup *parent;
2645         unsigned int nr_pages;
2646         unsigned long uninitialized_var(flags);
2647         int ret;
2648
2649         /* Is ROOT ? */
2650         if (!pcg)
2651                 return -EINVAL;
2652
2653         ret = -EBUSY;
2654         if (!get_page_unless_zero(page))
2655                 goto out;
2656         if (isolate_lru_page(page))
2657                 goto put;
2658
2659         nr_pages = hpage_nr_pages(page);
2660
2661         parent = mem_cgroup_from_cont(pcg);
2662         ret = __mem_cgroup_try_charge(NULL, gfp_mask, nr_pages, &parent, false);
2663         if (ret || !parent)
2664                 goto put_back;
2665
2666         if (nr_pages > 1)
2667                 flags = compound_lock_irqsave(page);
2668
2669         ret = mem_cgroup_move_account(page, nr_pages, pc, child, parent, true);
2670         if (ret)
2671                 __mem_cgroup_cancel_charge(parent, nr_pages);
2672
2673         if (nr_pages > 1)
2674                 compound_unlock_irqrestore(page, flags);
2675 put_back:
2676         putback_lru_page(page);
2677 put:
2678         put_page(page);
2679 out:
2680         return ret;
2681 }
2682
2683 /*
2684  * Charge the memory controller for page usage.
2685  * Return
2686  * 0 if the charge was successful
2687  * < 0 if the cgroup is over its limit
2688  */
2689 static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm,
2690                                 gfp_t gfp_mask, enum charge_type ctype)
2691 {
2692         struct mem_cgroup *mem = NULL;
2693         unsigned int nr_pages = 1;
2694         struct page_cgroup *pc;
2695         bool oom = true;
2696         int ret;
2697
2698         if (PageTransHuge(page)) {
2699                 nr_pages <<= compound_order(page);
2700                 VM_BUG_ON(!PageTransHuge(page));
2701                 /*
2702                  * Never OOM-kill a process for a huge page.  The
2703                  * fault handler will fall back to regular pages.
2704                  */
2705                 oom = false;
2706         }
2707
2708         pc = lookup_page_cgroup(page);
2709         BUG_ON(!pc); /* XXX: remove this and move pc lookup into commit */
2710
2711         ret = __mem_cgroup_try_charge(mm, gfp_mask, nr_pages, &mem, oom);
2712         if (ret || !mem)
2713                 return ret;
2714
2715         __mem_cgroup_commit_charge(mem, page, nr_pages, pc, ctype);
2716         return 0;
2717 }
2718
2719 int mem_cgroup_newpage_charge(struct page *page,
2720                               struct mm_struct *mm, gfp_t gfp_mask)
2721 {
2722         if (mem_cgroup_disabled())
2723                 return 0;
2724         /*
2725          * If already mapped, we don't have to account.
2726          * If page cache, page->mapping has address_space.
2727          * But page->mapping may have out-of-use anon_vma pointer,
2728          * detecit it by PageAnon() check. newly-mapped-anon's page->mapping
2729          * is NULL.
2730          */
2731         if (page_mapped(page) || (page->mapping && !PageAnon(page)))
2732                 return 0;
2733         if (unlikely(!mm))
2734                 mm = &init_mm;
2735         return mem_cgroup_charge_common(page, mm, gfp_mask,
2736                                 MEM_CGROUP_CHARGE_TYPE_MAPPED);
2737 }
2738
2739 static void
2740 __mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr,
2741                                         enum charge_type ctype);
2742
2743 static void
2744 __mem_cgroup_commit_charge_lrucare(struct page *page, struct mem_cgroup *mem,
2745                                         enum charge_type ctype)
2746 {
2747         struct page_cgroup *pc = lookup_page_cgroup(page);
2748         /*
2749          * In some case, SwapCache, FUSE(splice_buf->radixtree), the page
2750          * is already on LRU. It means the page may on some other page_cgroup's
2751          * LRU. Take care of it.
2752          */
2753         mem_cgroup_lru_del_before_commit(page);
2754         __mem_cgroup_commit_charge(mem, page, 1, pc, ctype);
2755         mem_cgroup_lru_add_after_commit(page);
2756         return;
2757 }
2758
2759 int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
2760                                 gfp_t gfp_mask)
2761 {
2762         struct mem_cgroup *mem = NULL;
2763         int ret;
2764
2765         if (mem_cgroup_disabled())
2766                 return 0;
2767         if (PageCompound(page))
2768                 return 0;
2769
2770         if (unlikely(!mm))
2771                 mm = &init_mm;
2772
2773         if (page_is_file_cache(page)) {
2774                 ret = __mem_cgroup_try_charge(mm, gfp_mask, 1, &mem, true);
2775                 if (ret || !mem)
2776                         return ret;
2777
2778                 /*
2779                  * FUSE reuses pages without going through the final
2780                  * put that would remove them from the LRU list, make
2781                  * sure that they get relinked properly.
2782                  */
2783                 __mem_cgroup_commit_charge_lrucare(page, mem,
2784                                         MEM_CGROUP_CHARGE_TYPE_CACHE);
2785                 return ret;
2786         }
2787         /* shmem */
2788         if (PageSwapCache(page)) {
2789                 ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &mem);
2790                 if (!ret)
2791                         __mem_cgroup_commit_charge_swapin(page, mem,
2792                                         MEM_CGROUP_CHARGE_TYPE_SHMEM);
2793         } else
2794                 ret = mem_cgroup_charge_common(page, mm, gfp_mask,
2795                                         MEM_CGROUP_CHARGE_TYPE_SHMEM);
2796
2797         return ret;
2798 }
2799
2800 /*
2801  * While swap-in, try_charge -> commit or cancel, the page is locked.
2802  * And when try_charge() successfully returns, one refcnt to memcg without
2803  * struct page_cgroup is acquired. This refcnt will be consumed by
2804  * "commit()" or removed by "cancel()"
2805  */
2806 int mem_cgroup_try_charge_swapin(struct mm_struct *mm,
2807                                  struct page *page,
2808                                  gfp_t mask, struct mem_cgroup **ptr)
2809 {
2810         struct mem_cgroup *mem;
2811         int ret;
2812
2813         *ptr = NULL;
2814
2815         if (mem_cgroup_disabled())
2816                 return 0;
2817
2818         if (!do_swap_account)
2819                 goto charge_cur_mm;
2820         /*
2821          * A racing thread's fault, or swapoff, may have already updated
2822          * the pte, and even removed page from swap cache: in those cases
2823          * do_swap_page()'s pte_same() test will fail; but there's also a
2824          * KSM case which does need to charge the page.
2825          */
2826         if (!PageSwapCache(page))
2827                 goto charge_cur_mm;
2828         mem = try_get_mem_cgroup_from_page(page);
2829         if (!mem)
2830                 goto charge_cur_mm;
2831         *ptr = mem;
2832         ret = __mem_cgroup_try_charge(NULL, mask, 1, ptr, true);
2833         css_put(&mem->css);
2834         return ret;
2835 charge_cur_mm:
2836         if (unlikely(!mm))
2837                 mm = &init_mm;
2838         return __mem_cgroup_try_charge(mm, mask, 1, ptr, true);
2839 }
2840
2841 static void
2842 __mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr,
2843                                         enum charge_type ctype)
2844 {
2845         if (mem_cgroup_disabled())
2846                 return;
2847         if (!ptr)
2848                 return;
2849         cgroup_exclude_rmdir(&ptr->css);
2850
2851         __mem_cgroup_commit_charge_lrucare(page, ptr, ctype);
2852         /*
2853          * Now swap is on-memory. This means this page may be
2854          * counted both as mem and swap....double count.
2855          * Fix it by uncharging from memsw. Basically, this SwapCache is stable
2856          * under lock_page(). But in do_swap_page()::memory.c, reuse_swap_page()
2857          * may call delete_from_swap_cache() before reach here.
2858          */
2859         if (do_swap_account && PageSwapCache(page)) {
2860                 swp_entry_t ent = {.val = page_private(page)};
2861                 unsigned short id;
2862                 struct mem_cgroup *memcg;
2863
2864                 id = swap_cgroup_record(ent, 0);
2865                 rcu_read_lock();
2866                 memcg = mem_cgroup_lookup(id);
2867                 if (memcg) {
2868                         /*
2869                          * This recorded memcg can be obsolete one. So, avoid
2870                          * calling css_tryget
2871                          */
2872                         if (!mem_cgroup_is_root(memcg))
2873                                 res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
2874                         mem_cgroup_swap_statistics(memcg, false);
2875                         mem_cgroup_put(memcg);
2876                 }
2877                 rcu_read_unlock();
2878         }
2879         /*
2880          * At swapin, we may charge account against cgroup which has no tasks.
2881          * So, rmdir()->pre_destroy() can be called while we do this charge.
2882          * In that case, we need to call pre_destroy() again. check it here.
2883          */
2884         cgroup_release_and_wakeup_rmdir(&ptr->css);
2885 }
2886
2887 void mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr)
2888 {
2889         __mem_cgroup_commit_charge_swapin(page, ptr,
2890                                         MEM_CGROUP_CHARGE_TYPE_MAPPED);
2891 }
2892
2893 void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *mem)
2894 {
2895         if (mem_cgroup_disabled())
2896                 return;
2897         if (!mem)
2898                 return;
2899         __mem_cgroup_cancel_charge(mem, 1);
2900 }
2901
2902 static void mem_cgroup_do_uncharge(struct mem_cgroup *mem,
2903                                    unsigned int nr_pages,
2904                                    const enum charge_type ctype)
2905 {
2906         struct memcg_batch_info *batch = NULL;
2907         bool uncharge_memsw = true;
2908
2909         /* If swapout, usage of swap doesn't decrease */
2910         if (!do_swap_account || ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT)
2911                 uncharge_memsw = false;
2912
2913         batch = &current->memcg_batch;
2914         /*
2915          * In usual, we do css_get() when we remember memcg pointer.
2916          * But in this case, we keep res->usage until end of a series of
2917          * uncharges. Then, it's ok to ignore memcg's refcnt.
2918          */
2919         if (!batch->memcg)
2920                 batch->memcg = mem;
2921         /*
2922          * do_batch > 0 when unmapping pages or inode invalidate/truncate.
2923          * In those cases, all pages freed continuously can be expected to be in
2924          * the same cgroup and we have chance to coalesce uncharges.
2925          * But we do uncharge one by one if this is killed by OOM(TIF_MEMDIE)
2926          * because we want to do uncharge as soon as possible.
2927          */
2928
2929         if (!batch->do_batch || test_thread_flag(TIF_MEMDIE))
2930                 goto direct_uncharge;
2931
2932         if (nr_pages > 1)
2933                 goto direct_uncharge;
2934
2935         /*
2936          * In typical case, batch->memcg == mem. This means we can
2937          * merge a series of uncharges to an uncharge of res_counter.
2938          * If not, we uncharge res_counter ony by one.
2939          */
2940         if (batch->memcg != mem)
2941                 goto direct_uncharge;
2942         /* remember freed charge and uncharge it later */
2943         batch->nr_pages++;
2944         if (uncharge_memsw)
2945                 batch->memsw_nr_pages++;
2946         return;
2947 direct_uncharge:
2948         res_counter_uncharge(&mem->res, nr_pages * PAGE_SIZE);
2949         if (uncharge_memsw)
2950                 res_counter_uncharge(&mem->memsw, nr_pages * PAGE_SIZE);
2951         if (unlikely(batch->memcg != mem))
2952                 memcg_oom_recover(mem);
2953         return;
2954 }
2955
2956 /*
2957  * uncharge if !page_mapped(page)
2958  */
2959 static struct mem_cgroup *
2960 __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
2961 {
2962         struct mem_cgroup *mem = NULL;
2963         unsigned int nr_pages = 1;
2964         struct page_cgroup *pc;
2965
2966         if (mem_cgroup_disabled())
2967                 return NULL;
2968
2969         if (PageSwapCache(page))
2970                 return NULL;
2971
2972         if (PageTransHuge(page)) {
2973                 nr_pages <<= compound_order(page);
2974                 VM_BUG_ON(!PageTransHuge(page));
2975         }
2976         /*
2977          * Check if our page_cgroup is valid
2978          */
2979         pc = lookup_page_cgroup(page);
2980         if (unlikely(!pc || !PageCgroupUsed(pc)))
2981                 return NULL;
2982
2983         lock_page_cgroup(pc);
2984
2985         mem = pc->mem_cgroup;
2986
2987         if (!PageCgroupUsed(pc))
2988                 goto unlock_out;
2989
2990         switch (ctype) {
2991         case MEM_CGROUP_CHARGE_TYPE_MAPPED:
2992         case MEM_CGROUP_CHARGE_TYPE_DROP:
2993                 /* See mem_cgroup_prepare_migration() */
2994                 if (page_mapped(page) || PageCgroupMigration(pc))
2995                         goto unlock_out;
2996                 break;
2997         case MEM_CGROUP_CHARGE_TYPE_SWAPOUT:
2998                 if (!PageAnon(page)) {  /* Shared memory */
2999                         if (page->mapping && !page_is_file_cache(page))
3000                                 goto unlock_out;
3001                 } else if (page_mapped(page)) /* Anon */
3002                                 goto unlock_out;
3003                 break;
3004         default:
3005                 break;
3006         }
3007
3008         mem_cgroup_charge_statistics(mem, PageCgroupCache(pc), -nr_pages);
3009
3010         ClearPageCgroupUsed(pc);
3011         /*
3012          * pc->mem_cgroup is not cleared here. It will be accessed when it's
3013          * freed from LRU. This is safe because uncharged page is expected not
3014          * to be reused (freed soon). Exception is SwapCache, it's handled by
3015          * special functions.
3016          */
3017
3018         unlock_page_cgroup(pc);
3019         /*
3020          * even after unlock, we have mem->res.usage here and this memcg
3021          * will never be freed.
3022          */
3023         memcg_check_events(mem, page);
3024         if (do_swap_account && ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT) {
3025                 mem_cgroup_swap_statistics(mem, true);
3026                 mem_cgroup_get(mem);
3027         }
3028         if (!mem_cgroup_is_root(mem))
3029                 mem_cgroup_do_uncharge(mem, nr_pages, ctype);
3030
3031         return mem;
3032
3033 unlock_out:
3034         unlock_page_cgroup(pc);
3035         return NULL;
3036 }
3037
3038 void mem_cgroup_uncharge_page(struct page *page)
3039 {
3040         /* early check. */
3041         if (page_mapped(page))
3042                 return;
3043         if (page->mapping && !PageAnon(page))
3044                 return;
3045         __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_MAPPED);
3046 }
3047
3048 void mem_cgroup_uncharge_cache_page(struct page *page)
3049 {
3050         VM_BUG_ON(page_mapped(page));
3051         VM_BUG_ON(page->mapping);
3052         __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE);
3053 }
3054
3055 /*
3056  * Batch_start/batch_end is called in unmap_page_range/invlidate/trucate.
3057  * In that cases, pages are freed continuously and we can expect pages
3058  * are in the same memcg. All these calls itself limits the number of
3059  * pages freed at once, then uncharge_start/end() is called properly.
3060  * This may be called prural(2) times in a context,
3061  */
3062
3063 void mem_cgroup_uncharge_start(void)
3064 {
3065         current->memcg_batch.do_batch++;
3066         /* We can do nest. */
3067         if (current->memcg_batch.do_batch == 1) {
3068                 current->memcg_batch.memcg = NULL;
3069                 current->memcg_batch.nr_pages = 0;
3070                 current->memcg_batch.memsw_nr_pages = 0;
3071         }
3072 }
3073
3074 void mem_cgroup_uncharge_end(void)
3075 {
3076         struct memcg_batch_info *batch = &current->memcg_batch;
3077
3078         if (!batch->do_batch)
3079                 return;
3080
3081         batch->do_batch--;
3082         if (batch->do_batch) /* If stacked, do nothing. */
3083                 return;
3084
3085         if (!batch->memcg)
3086                 return;
3087         /*
3088          * This "batch->memcg" is valid without any css_get/put etc...
3089          * bacause we hide charges behind us.
3090          */
3091         if (batch->nr_pages)
3092                 res_counter_uncharge(&batch->memcg->res,
3093                                      batch->nr_pages * PAGE_SIZE);
3094         if (batch->memsw_nr_pages)
3095                 res_counter_uncharge(&batch->memcg->memsw,
3096                                      batch->memsw_nr_pages * PAGE_SIZE);
3097         memcg_oom_recover(batch->memcg);
3098         /* forget this pointer (for sanity check) */
3099         batch->memcg = NULL;
3100 }
3101
3102 #ifdef CONFIG_SWAP
3103 /*
3104  * called after __delete_from_swap_cache() and drop "page" account.
3105  * memcg information is recorded to swap_cgroup of "ent"
3106  */
3107 void
3108 mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout)
3109 {
3110         struct mem_cgroup *memcg;
3111         int ctype = MEM_CGROUP_CHARGE_TYPE_SWAPOUT;
3112
3113         if (!swapout) /* this was a swap cache but the swap is unused ! */
3114                 ctype = MEM_CGROUP_CHARGE_TYPE_DROP;
3115
3116         memcg = __mem_cgroup_uncharge_common(page, ctype);
3117
3118         /*
3119          * record memcg information,  if swapout && memcg != NULL,
3120          * mem_cgroup_get() was called in uncharge().
3121          */
3122         if (do_swap_account && swapout && memcg)
3123                 swap_cgroup_record(ent, css_id(&memcg->css));
3124 }
3125 #endif
3126
3127 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
3128 /*
3129  * called from swap_entry_free(). remove record in swap_cgroup and
3130  * uncharge "memsw" account.
3131  */
3132 void mem_cgroup_uncharge_swap(swp_entry_t ent)
3133 {
3134         struct mem_cgroup *memcg;
3135         unsigned short id;
3136
3137         if (!do_swap_account)
3138                 return;
3139
3140         id = swap_cgroup_record(ent, 0);
3141         rcu_read_lock();
3142         memcg = mem_cgroup_lookup(id);
3143         if (memcg) {
3144                 /*
3145                  * We uncharge this because swap is freed.
3146                  * This memcg can be obsolete one. We avoid calling css_tryget
3147                  */
3148                 if (!mem_cgroup_is_root(memcg))
3149                         res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
3150                 mem_cgroup_swap_statistics(memcg, false);
3151                 mem_cgroup_put(memcg);
3152         }
3153         rcu_read_unlock();
3154 }
3155
3156 /**
3157  * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record.
3158  * @entry: swap entry to be moved
3159  * @from:  mem_cgroup which the entry is moved from
3160  * @to:  mem_cgroup which the entry is moved to
3161  * @need_fixup: whether we should fixup res_counters and refcounts.
3162  *
3163  * It succeeds only when the swap_cgroup's record for this entry is the same
3164  * as the mem_cgroup's id of @from.
3165  *
3166  * Returns 0 on success, -EINVAL on failure.
3167  *
3168  * The caller must have charged to @to, IOW, called res_counter_charge() about
3169  * both res and memsw, and called css_get().
3170  */
3171 static int mem_cgroup_move_swap_account(swp_entry_t entry,
3172                 struct mem_cgroup *from, struct mem_cgroup *to, bool need_fixup)
3173 {
3174         unsigned short old_id, new_id;
3175
3176         old_id = css_id(&from->css);
3177         new_id = css_id(&to->css);
3178
3179         if (swap_cgroup_cmpxchg(entry, old_id, new_id) == old_id) {
3180                 mem_cgroup_swap_statistics(from, false);
3181                 mem_cgroup_swap_statistics(to, true);
3182                 /*
3183                  * This function is only called from task migration context now.
3184                  * It postpones res_counter and refcount handling till the end
3185                  * of task migration(mem_cgroup_clear_mc()) for performance
3186                  * improvement. But we cannot postpone mem_cgroup_get(to)
3187                  * because if the process that has been moved to @to does
3188                  * swap-in, the refcount of @to might be decreased to 0.
3189                  */
3190                 mem_cgroup_get(to);
3191                 if (need_fixup) {
3192                         if (!mem_cgroup_is_root(from))
3193                                 res_counter_uncharge(&from->memsw, PAGE_SIZE);
3194                         mem_cgroup_put(from);
3195                         /*
3196                          * we charged both to->res and to->memsw, so we should
3197                          * uncharge to->res.
3198                          */
3199                         if (!mem_cgroup_is_root(to))
3200                                 res_counter_uncharge(&to->res, PAGE_SIZE);
3201                 }
3202                 return 0;
3203         }
3204         return -EINVAL;
3205 }
3206 #else
3207 static inline int mem_cgroup_move_swap_account(swp_entry_t entry,
3208                 struct mem_cgroup *from, struct mem_cgroup *to, bool need_fixup)
3209 {
3210         return -EINVAL;
3211 }
3212 #endif
3213
3214 /*
3215  * Before starting migration, account PAGE_SIZE to mem_cgroup that the old
3216  * page belongs to.
3217  */
3218 int mem_cgroup_prepare_migration(struct page *page,
3219         struct page *newpage, struct mem_cgroup **ptr, gfp_t gfp_mask)
3220 {
3221         struct mem_cgroup *mem = NULL;
3222         struct page_cgroup *pc;
3223         enum charge_type ctype;
3224         int ret = 0;
3225
3226         *ptr = NULL;
3227
3228         VM_BUG_ON(PageTransHuge(page));
3229         if (mem_cgroup_disabled())
3230                 return 0;
3231
3232         pc = lookup_page_cgroup(page);
3233         lock_page_cgroup(pc);
3234         if (PageCgroupUsed(pc)) {
3235                 mem = pc->mem_cgroup;
3236                 css_get(&mem->css);
3237                 /*
3238                  * At migrating an anonymous page, its mapcount goes down
3239                  * to 0 and uncharge() will be called. But, even if it's fully
3240                  * unmapped, migration may fail and this page has to be
3241                  * charged again. We set MIGRATION flag here and delay uncharge
3242                  * until end_migration() is called
3243                  *
3244                  * Corner Case Thinking
3245                  * A)
3246                  * When the old page was mapped as Anon and it's unmap-and-freed
3247                  * while migration was ongoing.
3248                  * If unmap finds the old page, uncharge() of it will be delayed
3249                  * until end_migration(). If unmap finds a new page, it's
3250                  * uncharged when it make mapcount to be 1->0. If unmap code
3251                  * finds swap_migration_entry, the new page will not be mapped
3252                  * and end_migration() will find it(mapcount==0).
3253                  *
3254                  * B)
3255                  * When the old page was mapped but migraion fails, the kernel
3256                  * remaps it. A charge for it is kept by MIGRATION flag even
3257                  * if mapcount goes down to 0. We can do remap successfully
3258                  * without charging it again.
3259                  *
3260                  * C)
3261                  * The "old" page is under lock_page() until the end of
3262                  * migration, so, the old page itself will not be swapped-out.
3263                  * If the new page is swapped out before end_migraton, our
3264                  * hook to usual swap-out path will catch the event.
3265                  */
3266                 if (PageAnon(page))
3267                         SetPageCgroupMigration(pc);
3268         }
3269         unlock_page_cgroup(pc);
3270         /*
3271          * If the page is not charged at this point,
3272          * we return here.
3273          */
3274         if (!mem)
3275                 return 0;
3276
3277         *ptr = mem;
3278         ret = __mem_cgroup_try_charge(NULL, gfp_mask, 1, ptr, false);
3279         css_put(&mem->css);/* drop extra refcnt */
3280         if (ret || *ptr == NULL) {
3281                 if (PageAnon(page)) {
3282                         lock_page_cgroup(pc);
3283                         ClearPageCgroupMigration(pc);
3284                         unlock_page_cgroup(pc);
3285                         /*
3286                          * The old page may be fully unmapped while we kept it.
3287                          */
3288                         mem_cgroup_uncharge_page(page);
3289                 }
3290                 return -ENOMEM;
3291         }
3292         /*
3293          * We charge new page before it's used/mapped. So, even if unlock_page()
3294          * is called before end_migration, we can catch all events on this new
3295          * page. In the case new page is migrated but not remapped, new page's
3296          * mapcount will be finally 0 and we call uncharge in end_migration().
3297          */
3298         pc = lookup_page_cgroup(newpage);
3299         if (PageAnon(page))
3300                 ctype = MEM_CGROUP_CHARGE_TYPE_MAPPED;
3301         else if (page_is_file_cache(page))
3302                 ctype = MEM_CGROUP_CHARGE_TYPE_CACHE;
3303         else
3304                 ctype = MEM_CGROUP_CHARGE_TYPE_SHMEM;
3305         __mem_cgroup_commit_charge(mem, page, 1, pc, ctype);
3306         return ret;
3307 }
3308
3309 /* remove redundant charge if migration failed*/
3310 void mem_cgroup_end_migration(struct mem_cgroup *mem,
3311         struct page *oldpage, struct page *newpage, bool migration_ok)
3312 {
3313         struct page *used, *unused;
3314         struct page_cgroup *pc;
3315
3316         if (!mem)
3317                 return;
3318         /* blocks rmdir() */
3319         cgroup_exclude_rmdir(&mem->css);
3320         if (!migration_ok) {
3321                 used = oldpage;
3322                 unused = newpage;
3323         } else {
3324                 used = newpage;
3325                 unused = oldpage;
3326         }
3327         /*
3328          * We disallowed uncharge of pages under migration because mapcount
3329          * of the page goes down to zero, temporarly.
3330          * Clear the flag and check the page should be charged.
3331          */
3332         pc = lookup_page_cgroup(oldpage);
3333         lock_page_cgroup(pc);
3334         ClearPageCgroupMigration(pc);
3335         unlock_page_cgroup(pc);
3336
3337         __mem_cgroup_uncharge_common(unused, MEM_CGROUP_CHARGE_TYPE_FORCE);
3338
3339         /*
3340          * If a page is a file cache, radix-tree replacement is very atomic
3341          * and we can skip this check. When it was an Anon page, its mapcount
3342          * goes down to 0. But because we added MIGRATION flage, it's not
3343          * uncharged yet. There are several case but page->mapcount check
3344          * and USED bit check in mem_cgroup_uncharge_page() will do enough
3345          * check. (see prepare_charge() also)
3346          */
3347         if (PageAnon(used))
3348                 mem_cgroup_uncharge_page(used);
3349         /*
3350          * At migration, we may charge account against cgroup which has no
3351          * tasks.
3352          * So, rmdir()->pre_destroy() can be called while we do this charge.
3353          * In that case, we need to call pre_destroy() again. check it here.
3354          */
3355         cgroup_release_and_wakeup_rmdir(&mem->css);
3356 }
3357
3358 /*
3359  * At replace page cache, newpage is not under any memcg but it's on
3360  * LRU. So, this function doesn't touch res_counter but handles LRU
3361  * in correct way. Both pages are locked so we cannot race with uncharge.
3362  */
3363 void mem_cgroup_replace_page_cache(struct page *oldpage,
3364                                   struct page *newpage)
3365 {
3366         struct mem_cgroup *memcg;
3367         struct page_cgroup *pc;
3368         struct zone *zone;
3369         enum charge_type type = MEM_CGROUP_CHARGE_TYPE_CACHE;
3370         unsigned long flags;
3371
3372         if (mem_cgroup_disabled())
3373                 return;
3374
3375         pc = lookup_page_cgroup(oldpage);
3376         /* fix accounting on old pages */
3377         lock_page_cgroup(pc);
3378         memcg = pc->mem_cgroup;
3379         mem_cgroup_charge_statistics(memcg, PageCgroupCache(pc), -1);
3380         ClearPageCgroupUsed(pc);
3381         unlock_page_cgroup(pc);
3382
3383         if (PageSwapBacked(oldpage))
3384                 type = MEM_CGROUP_CHARGE_TYPE_SHMEM;
3385
3386         zone = page_zone(newpage);
3387         pc = lookup_page_cgroup(newpage);
3388         /*
3389          * Even if newpage->mapping was NULL before starting replacement,
3390          * the newpage may be on LRU(or pagevec for LRU) already. We lock
3391          * LRU while we overwrite pc->mem_cgroup.
3392          */
3393         spin_lock_irqsave(&zone->lru_lock, flags);
3394         if (PageLRU(newpage))
3395                 del_page_from_lru_list(zone, newpage, page_lru(newpage));
3396         __mem_cgroup_commit_charge(memcg, newpage, 1, pc, type);
3397         if (PageLRU(newpage))
3398                 add_page_to_lru_list(zone, newpage, page_lru(newpage));
3399         spin_unlock_irqrestore(&zone->lru_lock, flags);
3400 }
3401
3402 #ifdef CONFIG_DEBUG_VM
3403 static struct page_cgroup *lookup_page_cgroup_used(struct page *page)
3404 {
3405         struct page_cgroup *pc;
3406
3407         pc = lookup_page_cgroup(page);
3408         if (likely(pc) && PageCgroupUsed(pc))
3409                 return pc;
3410         return NULL;
3411 }
3412
3413 bool mem_cgroup_bad_page_check(struct page *page)
3414 {
3415         if (mem_cgroup_disabled())
3416                 return false;
3417
3418         return lookup_page_cgroup_used(page) != NULL;
3419 }
3420
3421 void mem_cgroup_print_bad_page(struct page *page)
3422 {
3423         struct page_cgroup *pc;
3424
3425         pc = lookup_page_cgroup_used(page);
3426         if (pc) {
3427                 int ret = -1;
3428                 char *path;
3429
3430                 printk(KERN_ALERT "pc:%p pc->flags:%lx pc->mem_cgroup:%p",
3431                        pc, pc->flags, pc->mem_cgroup);
3432
3433                 path = kmalloc(PATH_MAX, GFP_KERNEL);
3434                 if (path) {
3435                         rcu_read_lock();
3436                         ret = cgroup_path(pc->mem_cgroup->css.cgroup,
3437                                                         path, PATH_MAX);
3438                         rcu_read_unlock();
3439                 }
3440
3441                 printk(KERN_CONT "(%s)\n",
3442                                 (ret < 0) ? "cannot get the path" : path);
3443                 kfree(path);
3444         }
3445 }
3446 #endif
3447
3448 static DEFINE_MUTEX(set_limit_mutex);
3449
3450 static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
3451                                 unsigned long long val)
3452 {
3453         int retry_count;
3454         u64 memswlimit, memlimit;
3455         int ret = 0;
3456         int children = mem_cgroup_count_children(memcg);
3457         u64 curusage, oldusage;
3458         int enlarge;
3459
3460         /*
3461          * For keeping hierarchical_reclaim simple, how long we should retry
3462          * is depends on callers. We set our retry-count to be function
3463          * of # of children which we should visit in this loop.
3464          */
3465         retry_count = MEM_CGROUP_RECLAIM_RETRIES * children;
3466
3467         oldusage = res_counter_read_u64(&memcg->res, RES_USAGE);
3468
3469         enlarge = 0;
3470         while (retry_count) {
3471                 if (signal_pending(current)) {
3472                         ret = -EINTR;
3473                         break;
3474                 }
3475                 /*
3476                  * Rather than hide all in some function, I do this in
3477                  * open coded manner. You see what this really does.
3478                  * We have to guarantee mem->res.limit < mem->memsw.limit.
3479                  */
3480                 mutex_lock(&set_limit_mutex);
3481                 memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
3482                 if (memswlimit < val) {
3483                         ret = -EINVAL;
3484                         mutex_unlock(&set_limit_mutex);
3485                         break;
3486                 }
3487
3488                 memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT);
3489                 if (memlimit < val)
3490                         enlarge = 1;
3491
3492                 ret = res_counter_set_limit(&memcg->res, val);
3493                 if (!ret) {
3494                         if (memswlimit == val)
3495                                 memcg->memsw_is_minimum = true;
3496                         else
3497                                 memcg->memsw_is_minimum = false;
3498                 }
3499                 mutex_unlock(&set_limit_mutex);
3500
3501                 if (!ret)
3502                         break;
3503
3504                 mem_cgroup_hierarchical_reclaim(memcg, NULL, GFP_KERNEL,
3505                                                 MEM_CGROUP_RECLAIM_SHRINK,
3506                                                 NULL);
3507                 curusage = res_counter_read_u64(&memcg->res, RES_USAGE);
3508                 /* Usage is reduced ? */
3509                 if (curusage >= oldusage)
3510                         retry_count--;
3511                 else
3512                         oldusage = curusage;
3513         }
3514         if (!ret && enlarge)
3515                 memcg_oom_recover(memcg);
3516
3517         return ret;
3518 }
3519
3520 static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
3521                                         unsigned long long val)
3522 {
3523         int retry_count;
3524         u64 memlimit, memswlimit, oldusage, curusage;
3525         int children = mem_cgroup_count_children(memcg);
3526         int ret = -EBUSY;
3527         int enlarge = 0;
3528
3529         /* see mem_cgroup_resize_res_limit */
3530         retry_count = children * MEM_CGROUP_RECLAIM_RETRIES;
3531         oldusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
3532         while (retry_count) {
3533                 if (signal_pending(current)) {
3534                         ret = -EINTR;
3535                         break;
3536                 }
3537                 /*
3538                  * Rather than hide all in some function, I do this in
3539                  * open coded manner. You see what this really does.
3540                  * We have to guarantee mem->res.limit < mem->memsw.limit.
3541                  */
3542                 mutex_lock(&set_limit_mutex);
3543                 memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT);
3544                 if (memlimit > val) {
3545                         ret = -EINVAL;
3546                         mutex_unlock(&set_limit_mutex);
3547                         break;
3548                 }
3549                 memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
3550                 if (memswlimit < val)
3551                         enlarge = 1;
3552                 ret = res_counter_set_limit(&memcg->memsw, val);
3553                 if (!ret) {
3554                         if (memlimit == val)
3555                                 memcg->memsw_is_minimum = true;
3556                         else
3557                                 memcg->memsw_is_minimum = false;
3558                 }
3559                 mutex_unlock(&set_limit_mutex);
3560
3561                 if (!ret)
3562                         break;
3563
3564                 mem_cgroup_hierarchical_reclaim(memcg, NULL, GFP_KERNEL,
3565                                                 MEM_CGROUP_RECLAIM_NOSWAP |
3566                                                 MEM_CGROUP_RECLAIM_SHRINK,
3567                                                 NULL);
3568                 curusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
3569                 /* Usage is reduced ? */
3570                 if (curusage >= oldusage)
3571                         retry_count--;
3572                 else
3573                         oldusage = curusage;
3574         }
3575         if (!ret && enlarge)
3576                 memcg_oom_recover(memcg);
3577         return ret;
3578 }
3579
3580 unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
3581                                             gfp_t gfp_mask,
3582                                             unsigned long *total_scanned)
3583 {
3584         unsigned long nr_reclaimed = 0;
3585         struct mem_cgroup_per_zone *mz, *next_mz = NULL;
3586         unsigned long reclaimed;
3587         int loop = 0;
3588         struct mem_cgroup_tree_per_zone *mctz;
3589         unsigned long long excess;
3590         unsigned long nr_scanned;
3591
3592         if (order > 0)
3593                 return 0;
3594
3595         mctz = soft_limit_tree_node_zone(zone_to_nid(zone), zone_idx(zone));
3596         /*
3597          * This loop can run a while, specially if mem_cgroup's continuously
3598          * keep exceeding their soft limit and putting the system under
3599          * pressure
3600          */
3601         do {
3602                 if (next_mz)
3603                         mz = next_mz;
3604                 else
3605                         mz = mem_cgroup_largest_soft_limit_node(mctz);
3606                 if (!mz)
3607                         break;
3608
3609                 nr_scanned = 0;
3610                 reclaimed = mem_cgroup_hierarchical_reclaim(mz->mem, zone,
3611                                                 gfp_mask,
3612                                                 MEM_CGROUP_RECLAIM_SOFT,
3613                                                 &nr_scanned);
3614                 nr_reclaimed += reclaimed;
3615                 *total_scanned += nr_scanned;
3616                 spin_lock(&mctz->lock);
3617
3618                 /*
3619                  * If we failed to reclaim anything from this memory cgroup
3620                  * it is time to move on to the next cgroup
3621                  */
3622                 next_mz = NULL;
3623                 if (!reclaimed) {
3624                         do {
3625                                 /*
3626                                  * Loop until we find yet another one.
3627                                  *
3628                                  * By the time we get the soft_limit lock
3629                                  * again, someone might have aded the
3630                                  * group back on the RB tree. Iterate to
3631                                  * make sure we get a different mem.
3632                                  * mem_cgroup_largest_soft_limit_node returns
3633                                  * NULL if no other cgroup is present on
3634                                  * the tree
3635                                  */
3636                                 next_mz =
3637                                 __mem_cgroup_largest_soft_limit_node(mctz);
3638                                 if (next_mz == mz)
3639                                         css_put(&next_mz->mem->css);
3640                                 else /* next_mz == NULL or other memcg */
3641                                         break;
3642                         } while (1);
3643                 }
3644                 __mem_cgroup_remove_exceeded(mz->mem, mz, mctz);
3645                 excess = res_counter_soft_limit_excess(&mz->mem->res);
3646                 /*
3647                  * One school of thought says that we should not add
3648                  * back the node to the tree if reclaim returns 0.
3649                  * But our reclaim could return 0, simply because due
3650                  * to priority we are exposing a smaller subset of
3651                  * memory to reclaim from. Consider this as a longer
3652                  * term TODO.
3653                  */
3654                 /* If excess == 0, no tree ops */
3655                 __mem_cgroup_insert_exceeded(mz->mem, mz, mctz, excess);
3656                 spin_unlock(&mctz->lock);
3657                 css_put(&mz->mem->css);
3658                 loop++;
3659                 /*
3660                  * Could not reclaim anything and there are no more
3661                  * mem cgroups to try or we seem to be looping without
3662                  * reclaiming anything.
3663                  */
3664                 if (!nr_reclaimed &&
3665                         (next_mz == NULL ||
3666                         loop > MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS))
3667                         break;
3668         } while (!nr_reclaimed);
3669         if (next_mz)
3670                 css_put(&next_mz->mem->css);
3671         return nr_reclaimed;
3672 }
3673
3674 /*
3675  * This routine traverse page_cgroup in given list and drop them all.
3676  * *And* this routine doesn't reclaim page itself, just removes page_cgroup.
3677  */
3678 static int mem_cgroup_force_empty_list(struct mem_cgroup *mem,
3679                                 int node, int zid, enum lru_list lru)
3680 {
3681         struct zone *zone;
3682         struct mem_cgroup_per_zone *mz;
3683         struct page_cgroup *pc, *busy;
3684         unsigned long flags, loop;
3685         struct list_head *list;
3686         int ret = 0;
3687
3688         zone = &NODE_DATA(node)->node_zones[zid];
3689         mz = mem_cgroup_zoneinfo(mem, node, zid);
3690         list = &mz->lists[lru];
3691
3692         loop = MEM_CGROUP_ZSTAT(mz, lru);
3693         /* give some margin against EBUSY etc...*/
3694         loop += 256;
3695         busy = NULL;
3696         while (loop--) {
3697                 struct page *page;
3698
3699                 ret = 0;
3700                 spin_lock_irqsave(&zone->lru_lock, flags);
3701                 if (list_empty(list)) {
3702                         spin_unlock_irqrestore(&zone->lru_lock, flags);
3703                         break;
3704                 }
3705                 pc = list_entry(list->prev, struct page_cgroup, lru);
3706                 if (busy == pc) {
3707                         list_move(&pc->lru, list);
3708                         busy = NULL;
3709                         spin_unlock_irqrestore(&zone->lru_lock, flags);
3710                         continue;
3711                 }
3712                 spin_unlock_irqrestore(&zone->lru_lock, flags);
3713
3714                 page = lookup_cgroup_page(pc);
3715
3716                 ret = mem_cgroup_move_parent(page, pc, mem, GFP_KERNEL);
3717                 if (ret == -ENOMEM)
3718                         break;
3719
3720                 if (ret == -EBUSY || ret == -EINVAL) {
3721                         /* found lock contention or "pc" is obsolete. */
3722                         busy = pc;
3723                         cond_resched();
3724                 } else
3725                         busy = NULL;
3726         }
3727
3728         if (!ret && !list_empty(list))
3729                 return -EBUSY;
3730         return ret;
3731 }
3732
3733 /*
3734  * make mem_cgroup's charge to be 0 if there is no task.
3735  * This enables deleting this mem_cgroup.
3736  */
3737 static int mem_cgroup_force_empty(struct mem_cgroup *mem, bool free_all)
3738 {
3739         int ret;
3740         int node, zid, shrink;
3741         int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
3742         struct cgroup *cgrp = mem->css.cgroup;
3743
3744         css_get(&mem->css);
3745
3746         shrink = 0;
3747         /* should free all ? */
3748         if (free_all)
3749                 goto try_to_free;
3750 move_account:
3751         do {
3752                 ret = -EBUSY;
3753                 if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children))
3754                         goto out;
3755                 ret = -EINTR;
3756                 if (signal_pending(current))
3757                         goto out;
3758                 /* This is for making all *used* pages to be on LRU. */
3759                 lru_add_drain_all();
3760                 drain_all_stock_sync(mem);
3761                 ret = 0;
3762                 mem_cgroup_start_move(mem);
3763                 for_each_node_state(node, N_HIGH_MEMORY) {
3764                         for (zid = 0; !ret && zid < MAX_NR_ZONES; zid++) {
3765                                 enum lru_list l;
3766                                 for_each_lru(l) {
3767                                         ret = mem_cgroup_force_empty_list(mem,
3768                                                         node, zid, l);
3769                                         if (ret)
3770                                                 break;
3771                                 }
3772                         }
3773                         if (ret)
3774                                 break;
3775                 }
3776                 mem_cgroup_end_move(mem);
3777                 memcg_oom_recover(mem);
3778                 /* it seems parent cgroup doesn't have enough mem */
3779                 if (ret == -ENOMEM)
3780                         goto try_to_free;
3781                 cond_resched();
3782         /* "ret" should also be checked to ensure all lists are empty. */
3783         } while (mem->res.usage > 0 || ret);
3784 out:
3785         css_put(&mem->css);
3786         return ret;
3787
3788 try_to_free:
3789         /* returns EBUSY if there is a task or if we come here twice. */
3790         if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children) || shrink) {
3791                 ret = -EBUSY;
3792                 goto out;
3793         }
3794         /* we call try-to-free pages for make this cgroup empty */
3795         lru_add_drain_all();
3796         /* try to free all pages in this cgroup */
3797         shrink = 1;
3798         while (nr_retries && mem->res.usage > 0) {
3799                 int progress;
3800
3801                 if (signal_pending(current)) {
3802                         ret = -EINTR;
3803                         goto out;
3804                 }
3805                 progress = try_to_free_mem_cgroup_pages(mem, GFP_KERNEL,
3806                                                 false);
3807                 if (!progress) {
3808                         nr_retries--;
3809                         /* maybe some writeback is necessary */
3810                         congestion_wait(BLK_RW_ASYNC, HZ/10);
3811                 }
3812
3813         }
3814         lru_add_drain();
3815         /* try move_account...there may be some *locked* pages. */
3816         goto move_account;
3817 }
3818
3819 int mem_cgroup_force_empty_write(struct cgroup *cont, unsigned int event)
3820 {
3821         return mem_cgroup_force_empty(mem_cgroup_from_cont(cont), true);
3822 }
3823
3824
3825 static u64 mem_cgroup_hierarchy_read(struct cgroup *cont, struct cftype *cft)
3826 {
3827         return mem_cgroup_from_cont(cont)->use_hierarchy;
3828 }
3829
3830 static int mem_cgroup_hierarchy_write(struct cgroup *cont, struct cftype *cft,
3831                                         u64 val)
3832 {
3833         int retval = 0;
3834         struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
3835         struct cgroup *parent = cont->parent;
3836         struct mem_cgroup *parent_mem = NULL;
3837
3838         if (parent)
3839                 parent_mem = mem_cgroup_from_cont(parent);
3840
3841         cgroup_lock();
3842         /*
3843          * If parent's use_hierarchy is set, we can't make any modifications
3844          * in the child subtrees. If it is unset, then the change can
3845          * occur, provided the current cgroup has no children.
3846          *
3847          * For the root cgroup, parent_mem is NULL, we allow value to be
3848          * set if there are no children.
3849          */
3850         if ((!parent_mem || !parent_mem->use_hierarchy) &&
3851                                 (val == 1 || val == 0)) {
3852                 if (list_empty(&cont->children))
3853                         mem->use_hierarchy = val;
3854                 else
3855                         retval = -EBUSY;
3856         } else
3857                 retval = -EINVAL;
3858         cgroup_unlock();
3859
3860         return retval;
3861 }
3862
3863
3864 static unsigned long mem_cgroup_recursive_stat(struct mem_cgroup *mem,
3865                                                enum mem_cgroup_stat_index idx)
3866 {
3867         struct mem_cgroup *iter;
3868         long val = 0;
3869
3870         /* Per-cpu values can be negative, use a signed accumulator */
3871         for_each_mem_cgroup_tree(iter, mem)
3872                 val += mem_cgroup_read_stat(iter, idx);
3873
3874         if (val < 0) /* race ? */
3875                 val = 0;
3876         return val;
3877 }
3878
3879 static inline u64 mem_cgroup_usage(struct mem_cgroup *mem, bool swap)
3880 {
3881         u64 val;
3882
3883         if (!mem_cgroup_is_root(mem)) {
3884                 if (!swap)
3885                         return res_counter_read_u64(&mem->res, RES_USAGE);
3886                 else
3887                         return res_counter_read_u64(&mem->memsw, RES_USAGE);
3888         }
3889
3890         val = mem_cgroup_recursive_stat(mem, MEM_CGROUP_STAT_CACHE);
3891         val += mem_cgroup_recursive_stat(mem, MEM_CGROUP_STAT_RSS);
3892
3893         if (swap)
3894                 val += mem_cgroup_recursive_stat(mem, MEM_CGROUP_STAT_SWAPOUT);
3895
3896         return val << PAGE_SHIFT;
3897 }
3898
3899 static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft)
3900 {
3901         struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
3902         u64 val;
3903         int type, name;
3904
3905         type = MEMFILE_TYPE(cft->private);
3906         name = MEMFILE_ATTR(cft->private);
3907         switch (type) {
3908         case _MEM:
3909                 if (name == RES_USAGE)
3910                         val = mem_cgroup_usage(mem, false);
3911                 else
3912                         val = res_counter_read_u64(&mem->res, name);
3913                 break;
3914         case _MEMSWAP:
3915                 if (name == RES_USAGE)
3916                         val = mem_cgroup_usage(mem, true);
3917                 else
3918                         val = res_counter_read_u64(&mem->memsw, name);
3919                 break;
3920         default:
3921                 BUG();
3922                 break;
3923         }
3924         return val;
3925 }
3926 /*
3927  * The user of this function is...
3928  * RES_LIMIT.
3929  */
3930 static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
3931                             const char *buffer)
3932 {
3933         struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
3934         int type, name;
3935         unsigned long long val;
3936         int ret;
3937
3938         type = MEMFILE_TYPE(cft->private);
3939         name = MEMFILE_ATTR(cft->private);
3940         switch (name) {
3941         case RES_LIMIT:
3942                 if (mem_cgroup_is_root(memcg)) { /* Can't set limit on root */
3943                         ret = -EINVAL;
3944                         break;
3945                 }
3946                 /* This function does all necessary parse...reuse it */
3947                 ret = res_counter_memparse_write_strategy(buffer, &val);
3948                 if (ret)
3949                         break;
3950                 if (type == _MEM)
3951                         ret = mem_cgroup_resize_limit(memcg, val);
3952                 else
3953                         ret = mem_cgroup_resize_memsw_limit(memcg, val);
3954                 break;
3955         case RES_SOFT_LIMIT:
3956                 ret = res_counter_memparse_write_strategy(buffer, &val);
3957                 if (ret)
3958                         break;
3959                 /*
3960                  * For memsw, soft limits are hard to implement in terms
3961                  * of semantics, for now, we support soft limits for
3962                  * control without swap
3963                  */
3964                 if (type == _MEM)
3965                         ret = res_counter_set_soft_limit(&memcg->res, val);
3966                 else
3967                         ret = -EINVAL;
3968                 break;
3969         default:
3970                 ret = -EINVAL; /* should be BUG() ? */
3971                 break;
3972         }
3973         return ret;
3974 }
3975
3976 static void memcg_get_hierarchical_limit(struct mem_cgroup *memcg,
3977                 unsigned long long *mem_limit, unsigned long long *memsw_limit)
3978 {
3979         struct cgroup *cgroup;
3980         unsigned long long min_limit, min_memsw_limit, tmp;
3981
3982         min_limit = res_counter_read_u64(&memcg->res, RES_LIMIT);
3983         min_memsw_limit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
3984         cgroup = memcg->css.cgroup;
3985         if (!memcg->use_hierarchy)
3986                 goto out;
3987
3988         while (cgroup->parent) {
3989                 cgroup = cgroup->parent;
3990                 memcg = mem_cgroup_from_cont(cgroup);
3991                 if (!memcg->use_hierarchy)
3992                         break;
3993                 tmp = res_counter_read_u64(&memcg->res, RES_LIMIT);
3994                 min_limit = min(min_limit, tmp);
3995                 tmp = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
3996                 min_memsw_limit = min(min_memsw_limit, tmp);
3997         }
3998 out:
3999         *mem_limit = min_limit;
4000         *memsw_limit = min_memsw_limit;
4001         return;
4002 }
4003
4004 static int mem_cgroup_reset(struct cgroup *cont, unsigned int event)
4005 {
4006         struct mem_cgroup *mem;
4007         int type, name;
4008
4009         mem = mem_cgroup_from_cont(cont);
4010         type = MEMFILE_TYPE(event);
4011         name = MEMFILE_ATTR(event);
4012         switch (name) {
4013         case RES_MAX_USAGE:
4014                 if (type == _MEM)
4015                         res_counter_reset_max(&mem->res);
4016                 else
4017                         res_counter_reset_max(&mem->memsw);
4018                 break;
4019         case RES_FAILCNT:
4020                 if (type == _MEM)
4021                         res_counter_reset_failcnt(&mem->res);
4022                 else
4023                         res_counter_reset_failcnt(&mem->memsw);
4024                 break;
4025         }
4026
4027         return 0;
4028 }
4029
4030 static u64 mem_cgroup_move_charge_read(struct cgroup *cgrp,
4031                                         struct cftype *cft)
4032 {
4033         return mem_cgroup_from_cont(cgrp)->move_charge_at_immigrate;
4034 }
4035
4036 #ifdef CONFIG_MMU
4037 static int mem_cgroup_move_charge_write(struct cgroup *cgrp,
4038                                         struct cftype *cft, u64 val)
4039 {
4040         struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp);
4041
4042         if (val >= (1 << NR_MOVE_TYPE))
4043                 return -EINVAL;
4044         /*
4045          * We check this value several times in both in can_attach() and
4046          * attach(), so we need cgroup lock to prevent this value from being
4047          * inconsistent.
4048          */
4049         cgroup_lock();
4050         mem->move_charge_at_immigrate = val;
4051         cgroup_unlock();
4052
4053         return 0;
4054 }
4055 #else
4056 static int mem_cgroup_move_charge_write(struct cgroup *cgrp,
4057                                         struct cftype *cft, u64 val)
4058 {
4059         return -ENOSYS;
4060 }
4061 #endif
4062
4063
4064 /* For read statistics */
4065 enum {
4066         MCS_CACHE,
4067         MCS_RSS,
4068         MCS_FILE_MAPPED,
4069         MCS_PGPGIN,
4070         MCS_PGPGOUT,
4071         MCS_SWAP,
4072         MCS_PGFAULT,
4073         MCS_PGMAJFAULT,
4074         MCS_INACTIVE_ANON,
4075         MCS_ACTIVE_ANON,
4076         MCS_INACTIVE_FILE,
4077         MCS_ACTIVE_FILE,
4078         MCS_UNEVICTABLE,
4079         NR_MCS_STAT,
4080 };
4081
4082 struct mcs_total_stat {
4083         s64 stat[NR_MCS_STAT];
4084 };
4085
4086 struct {
4087         char *local_name;
4088         char *total_name;
4089 } memcg_stat_strings[NR_MCS_STAT] = {
4090         {"cache", "total_cache"},
4091         {"rss", "total_rss"},
4092         {"mapped_file", "total_mapped_file"},
4093         {"pgpgin", "total_pgpgin"},
4094         {"pgpgout", "total_pgpgout"},
4095         {"swap", "total_swap"},
4096         {"pgfault", "total_pgfault"},
4097         {"pgmajfault", "total_pgmajfault"},
4098         {"inactive_anon", "total_inactive_anon"},
4099         {"active_anon", "total_active_anon"},
4100         {"inactive_file", "total_inactive_file"},
4101         {"active_file", "total_active_file"},
4102         {"unevictable", "total_unevictable"}
4103 };
4104
4105
4106 static void
4107 mem_cgroup_get_local_stat(struct mem_cgroup *mem, struct mcs_total_stat *s)
4108 {
4109         s64 val;
4110
4111         /* per cpu stat */
4112         val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_CACHE);
4113         s->stat[MCS_CACHE] += val * PAGE_SIZE;
4114         val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_RSS);
4115         s->stat[MCS_RSS] += val * PAGE_SIZE;
4116         val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_FILE_MAPPED);
4117         s->stat[MCS_FILE_MAPPED] += val * PAGE_SIZE;
4118         val = mem_cgroup_read_events(mem, MEM_CGROUP_EVENTS_PGPGIN);
4119         s->stat[MCS_PGPGIN] += val;
4120         val = mem_cgroup_read_events(mem, MEM_CGROUP_EVENTS_PGPGOUT);
4121         s->stat[MCS_PGPGOUT] += val;
4122         if (do_swap_account) {
4123                 val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_SWAPOUT);
4124                 s->stat[MCS_SWAP] += val * PAGE_SIZE;
4125         }
4126         val = mem_cgroup_read_events(mem, MEM_CGROUP_EVENTS_PGFAULT);
4127         s->stat[MCS_PGFAULT] += val;
4128         val = mem_cgroup_read_events(mem, MEM_CGROUP_EVENTS_PGMAJFAULT);
4129         s->stat[MCS_PGMAJFAULT] += val;
4130
4131         /* per zone stat */
4132         val = mem_cgroup_nr_lru_pages(mem, BIT(LRU_INACTIVE_ANON));
4133         s->stat[MCS_INACTIVE_ANON] += val * PAGE_SIZE;
4134         val = mem_cgroup_nr_lru_pages(mem, BIT(LRU_ACTIVE_ANON));
4135         s->stat[MCS_ACTIVE_ANON] += val * PAGE_SIZE;
4136         val = mem_cgroup_nr_lru_pages(mem, BIT(LRU_INACTIVE_FILE));
4137         s->stat[MCS_INACTIVE_FILE] += val * PAGE_SIZE;
4138         val = mem_cgroup_nr_lru_pages(mem, BIT(LRU_ACTIVE_FILE));
4139         s->stat[MCS_ACTIVE_FILE] += val * PAGE_SIZE;
4140         val = mem_cgroup_nr_lru_pages(mem, BIT(LRU_UNEVICTABLE));
4141         s->stat[MCS_UNEVICTABLE] += val * PAGE_SIZE;
4142 }
4143
4144 static void
4145 mem_cgroup_get_total_stat(struct mem_cgroup *mem, struct mcs_total_stat *s)
4146 {
4147         struct mem_cgroup *iter;
4148
4149         for_each_mem_cgroup_tree(iter, mem)
4150                 mem_cgroup_get_local_stat(iter, s);
4151 }
4152
4153 #ifdef CONFIG_NUMA
4154 static int mem_control_numa_stat_show(struct seq_file *m, void *arg)
4155 {
4156         int nid;
4157         unsigned long total_nr, file_nr, anon_nr, unevictable_nr;
4158         unsigned long node_nr;
4159         struct cgroup *cont = m->private;
4160         struct mem_cgroup *mem_cont = mem_cgroup_from_cont(cont);
4161
4162         total_nr = mem_cgroup_nr_lru_pages(mem_cont, LRU_ALL);
4163         seq_printf(m, "total=%lu", total_nr);
4164         for_each_node_state(nid, N_HIGH_MEMORY) {
4165                 node_nr = mem_cgroup_node_nr_lru_pages(mem_cont, nid, LRU_ALL);
4166                 seq_printf(m, " N%d=%lu", nid, node_nr);
4167         }
4168         seq_putc(m, '\n');
4169
4170         file_nr = mem_cgroup_nr_lru_pages(mem_cont, LRU_ALL_FILE);
4171         seq_printf(m, "file=%lu", file_nr);
4172         for_each_node_state(nid, N_HIGH_MEMORY) {
4173                 node_nr = mem_cgroup_node_nr_lru_pages(mem_cont, nid,
4174                                 LRU_ALL_FILE);
4175                 seq_printf(m, " N%d=%lu", nid, node_nr);
4176         }
4177         seq_putc(m, '\n');
4178
4179         anon_nr = mem_cgroup_nr_lru_pages(mem_cont, LRU_ALL_ANON);
4180         seq_printf(m, "anon=%lu", anon_nr);
4181         for_each_node_state(nid, N_HIGH_MEMORY) {
4182                 node_nr = mem_cgroup_node_nr_lru_pages(mem_cont, nid,
4183                                 LRU_ALL_ANON);
4184                 seq_printf(m, " N%d=%lu", nid, node_nr);
4185         }
4186         seq_putc(m, '\n');
4187
4188         unevictable_nr = mem_cgroup_nr_lru_pages(mem_cont, BIT(LRU_UNEVICTABLE));
4189         seq_printf(m, "unevictable=%lu", unevictable_nr);
4190         for_each_node_state(nid, N_HIGH_MEMORY) {
4191                 node_nr = mem_cgroup_node_nr_lru_pages(mem_cont, nid,
4192                                 BIT(LRU_UNEVICTABLE));
4193                 seq_printf(m, " N%d=%lu", nid, node_nr);
4194         }
4195         seq_putc(m, '\n');
4196         return 0;
4197 }
4198 #endif /* CONFIG_NUMA */
4199
4200 static int mem_control_stat_show(struct cgroup *cont, struct cftype *cft,
4201                                  struct cgroup_map_cb *cb)
4202 {
4203         struct mem_cgroup *mem_cont = mem_cgroup_from_cont(cont);
4204         struct mcs_total_stat mystat;
4205         int i;
4206
4207         memset(&mystat, 0, sizeof(mystat));
4208         mem_cgroup_get_local_stat(mem_cont, &mystat);
4209
4210
4211         for (i = 0; i < NR_MCS_STAT; i++) {
4212                 if (i == MCS_SWAP && !do_swap_account)
4213                         continue;
4214                 cb->fill(cb, memcg_stat_strings[i].local_name, mystat.stat[i]);
4215         }
4216
4217         /* Hierarchical information */
4218         {
4219                 unsigned long long limit, memsw_limit;
4220                 memcg_get_hierarchical_limit(mem_cont, &limit, &memsw_limit);
4221                 cb->fill(cb, "hierarchical_memory_limit", limit);
4222                 if (do_swap_account)
4223                         cb->fill(cb, "hierarchical_memsw_limit", memsw_limit);
4224         }
4225
4226         memset(&mystat, 0, sizeof(mystat));
4227         mem_cgroup_get_total_stat(mem_cont, &mystat);
4228         for (i = 0; i < NR_MCS_STAT; i++) {
4229                 if (i == MCS_SWAP && !do_swap_account)
4230                         continue;
4231                 cb->fill(cb, memcg_stat_strings[i].total_name, mystat.stat[i]);
4232         }
4233
4234 #ifdef CONFIG_DEBUG_VM
4235         cb->fill(cb, "inactive_ratio", calc_inactive_ratio(mem_cont, NULL));
4236
4237         {
4238                 int nid, zid;
4239                 struct mem_cgroup_per_zone *mz;
4240                 unsigned long recent_rotated[2] = {0, 0};
4241                 unsigned long recent_scanned[2] = {0, 0};
4242
4243                 for_each_online_node(nid)
4244                         for (zid = 0; zid < MAX_NR_ZONES; zid++) {
4245                                 mz = mem_cgroup_zoneinfo(mem_cont, nid, zid);
4246
4247                                 recent_rotated[0] +=
4248                                         mz->reclaim_stat.recent_rotated[0];
4249                                 recent_rotated[1] +=
4250                                         mz->reclaim_stat.recent_rotated[1];
4251                                 recent_scanned[0] +=
4252                                         mz->reclaim_stat.recent_scanned[0];
4253                                 recent_scanned[1] +=
4254                                         mz->reclaim_stat.recent_scanned[1];
4255                         }
4256                 cb->fill(cb, "recent_rotated_anon", recent_rotated[0]);
4257                 cb->fill(cb, "recent_rotated_file", recent_rotated[1]);
4258                 cb->fill(cb, "recent_scanned_anon", recent_scanned[0]);
4259                 cb->fill(cb, "recent_scanned_file", recent_scanned[1]);
4260         }
4261 #endif
4262
4263         return 0;
4264 }
4265
4266 static u64 mem_cgroup_swappiness_read(struct cgroup *cgrp, struct cftype *cft)
4267 {
4268         struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
4269
4270         return mem_cgroup_swappiness(memcg);
4271 }
4272
4273 static int mem_cgroup_swappiness_write(struct cgroup *cgrp, struct cftype *cft,
4274                                        u64 val)
4275 {
4276         struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
4277         struct mem_cgroup *parent;
4278
4279         if (val > 100)
4280                 return -EINVAL;
4281
4282         if (cgrp->parent == NULL)
4283                 return -EINVAL;
4284
4285         parent = mem_cgroup_from_cont(cgrp->parent);
4286
4287         cgroup_lock();
4288
4289         /* If under hierarchy, only empty-root can set this value */
4290         if ((parent->use_hierarchy) ||
4291             (memcg->use_hierarchy && !list_empty(&cgrp->children))) {
4292                 cgroup_unlock();
4293                 return -EINVAL;
4294         }
4295
4296         memcg->swappiness = val;
4297
4298         cgroup_unlock();
4299
4300         return 0;
4301 }
4302
4303 static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap)
4304 {
4305         struct mem_cgroup_threshold_ary *t;
4306         u64 usage;
4307         int i;
4308
4309         rcu_read_lock();
4310         if (!swap)
4311                 t = rcu_dereference(memcg->thresholds.primary);
4312         else
4313                 t = rcu_dereference(memcg->memsw_thresholds.primary);
4314
4315         if (!t)
4316                 goto unlock;
4317
4318         usage = mem_cgroup_usage(memcg, swap);
4319
4320         /*
4321          * current_threshold points to threshold just below usage.
4322          * If it's not true, a threshold was crossed after last
4323          * call of __mem_cgroup_threshold().
4324          */
4325         i = t->current_threshold;
4326
4327         /*
4328          * Iterate backward over array of thresholds starting from
4329          * current_threshold and check if a threshold is crossed.
4330          * If none of thresholds below usage is crossed, we read
4331          * only one element of the array here.
4332          */
4333         for (; i >= 0 && unlikely(t->entries[i].threshold > usage); i--)
4334                 eventfd_signal(t->entries[i].eventfd, 1);
4335
4336         /* i = current_threshold + 1 */
4337         i++;
4338
4339         /*
4340          * Iterate forward over array of thresholds starting from
4341          * current_threshold+1 and check if a threshold is crossed.
4342          * If none of thresholds above usage is crossed, we read
4343          * only one element of the array here.
4344          */
4345         for (; i < t->size && unlikely(t->entries[i].threshold <= usage); i++)
4346                 eventfd_signal(t->entries[i].eventfd, 1);
4347
4348         /* Update current_threshold */
4349         t->current_threshold = i - 1;
4350 unlock:
4351         rcu_read_unlock();
4352 }
4353
4354 static void mem_cgroup_threshold(struct mem_cgroup *memcg)
4355 {
4356         while (memcg) {
4357                 __mem_cgroup_threshold(memcg, false);
4358                 if (do_swap_account)
4359                         __mem_cgroup_threshold(memcg, true);
4360
4361                 memcg = parent_mem_cgroup(memcg);
4362         }
4363 }
4364
4365 static int compare_thresholds(const void *a, const void *b)
4366 {
4367         const struct mem_cgroup_threshold *_a = a;
4368         const struct mem_cgroup_threshold *_b = b;
4369
4370         return _a->threshold - _b->threshold;
4371 }
4372
4373 static int mem_cgroup_oom_notify_cb(struct mem_cgroup *mem)
4374 {
4375         struct mem_cgroup_eventfd_list *ev;
4376
4377         list_for_each_entry(ev, &mem->oom_notify, list)
4378                 eventfd_signal(ev->eventfd, 1);
4379         return 0;
4380 }
4381
4382 static void mem_cgroup_oom_notify(struct mem_cgroup *mem)
4383 {
4384         struct mem_cgroup *iter;
4385
4386         for_each_mem_cgroup_tree(iter, mem)
4387                 mem_cgroup_oom_notify_cb(iter);
4388 }
4389
4390 static int mem_cgroup_usage_register_event(struct cgroup *cgrp,
4391         struct cftype *cft, struct eventfd_ctx *eventfd, const char *args)
4392 {
4393         struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
4394         struct mem_cgroup_thresholds *thresholds;
4395         struct mem_cgroup_threshold_ary *new;
4396         int type = MEMFILE_TYPE(cft->private);
4397         u64 threshold, usage;
4398         int i, size, ret;
4399
4400         ret = res_counter_memparse_write_strategy(args, &threshold);
4401         if (ret)
4402                 return ret;
4403
4404         mutex_lock(&memcg->thresholds_lock);
4405
4406         if (type == _MEM)
4407                 thresholds = &memcg->thresholds;
4408         else if (type == _MEMSWAP)
4409                 thresholds = &memcg->memsw_thresholds;
4410         else
4411                 BUG();
4412
4413         usage = mem_cgroup_usage(memcg, type == _MEMSWAP);
4414
4415         /* Check if a threshold crossed before adding a new one */
4416         if (thresholds->primary)
4417                 __mem_cgroup_threshold(memcg, type == _MEMSWAP);
4418
4419         size = thresholds->primary ? thresholds->primary->size + 1 : 1;
4420
4421         /* Allocate memory for new array of thresholds */
4422         new = kmalloc(sizeof(*new) + size * sizeof(struct mem_cgroup_threshold),
4423                         GFP_KERNEL);
4424         if (!new) {
4425                 ret = -ENOMEM;
4426                 goto unlock;
4427         }
4428         new->size = size;
4429
4430         /* Copy thresholds (if any) to new array */
4431         if (thresholds->primary) {
4432                 memcpy(new->entries, thresholds->primary->entries, (size - 1) *
4433                                 sizeof(struct mem_cgroup_threshold));
4434         }
4435
4436         /* Add new threshold */
4437         new->entries[size - 1].eventfd = eventfd;
4438         new->entries[size - 1].threshold = threshold;
4439
4440         /* Sort thresholds. Registering of new threshold isn't time-critical */
4441         sort(new->entries, size, sizeof(struct mem_cgroup_threshold),
4442                         compare_thresholds, NULL);
4443
4444         /* Find current threshold */
4445         new->current_threshold = -1;
4446         for (i = 0; i < size; i++) {
4447                 if (new->entries[i].threshold < usage) {
4448                         /*
4449                          * new->current_threshold will not be used until
4450                          * rcu_assign_pointer(), so it's safe to increment
4451                          * it here.
4452                          */
4453                         ++new->current_threshold;
4454                 }
4455         }
4456
4457         /* Free old spare buffer and save old primary buffer as spare */
4458         kfree(thresholds->spare);
4459         thresholds->spare = thresholds->primary;
4460
4461         rcu_assign_pointer(thresholds->primary, new);
4462
4463         /* To be sure that nobody uses thresholds */
4464         synchronize_rcu();
4465
4466 unlock:
4467         mutex_unlock(&memcg->thresholds_lock);
4468
4469         return ret;
4470 }
4471
4472 static void mem_cgroup_usage_unregister_event(struct cgroup *cgrp,
4473         struct cftype *cft, struct eventfd_ctx *eventfd)
4474 {
4475         struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
4476         struct mem_cgroup_thresholds *thresholds;
4477         struct mem_cgroup_threshold_ary *new;
4478         int type = MEMFILE_TYPE(cft->private);
4479         u64 usage;
4480         int i, j, size;
4481
4482         mutex_lock(&memcg->thresholds_lock);
4483         if (type == _MEM)
4484                 thresholds = &memcg->thresholds;
4485         else if (type == _MEMSWAP)
4486                 thresholds = &memcg->memsw_thresholds;
4487         else
4488                 BUG();
4489
4490         /*
4491          * Something went wrong if we trying to unregister a threshold
4492          * if we don't have thresholds
4493          */
4494         BUG_ON(!thresholds);
4495
4496         usage = mem_cgroup_usage(memcg, type == _MEMSWAP);
4497
4498         /* Check if a threshold crossed before removing */
4499         __mem_cgroup_threshold(memcg, type == _MEMSWAP);
4500
4501         /* Calculate new number of threshold */
4502         size = 0;
4503         for (i = 0; i < thresholds->primary->size; i++) {
4504                 if (thresholds->primary->entries[i].eventfd != eventfd)
4505                         size++;
4506         }
4507
4508         new = thresholds->spare;
4509
4510         /* Set thresholds array to NULL if we don't have thresholds */
4511         if (!size) {
4512                 kfree(new);
4513                 new = NULL;
4514                 goto swap_buffers;
4515         }
4516
4517         new->size = size;
4518
4519         /* Copy thresholds and find current threshold */
4520         new->current_threshold = -1;
4521         for (i = 0, j = 0; i < thresholds->primary->size; i++) {
4522                 if (thresholds->primary->entries[i].eventfd == eventfd)
4523                         continue;
4524
4525                 new->entries[j] = thresholds->primary->entries[i];
4526                 if (new->entries[j].threshold < usage) {
4527                         /*
4528                          * new->current_threshold will not be used
4529                          * until rcu_assign_pointer(), so it's safe to increment
4530                          * it here.
4531                          */
4532                         ++new->current_threshold;
4533                 }
4534                 j++;
4535         }
4536
4537 swap_buffers:
4538         /* Swap primary and spare array */
4539         thresholds->spare = thresholds->primary;
4540         rcu_assign_pointer(thresholds->primary, new);
4541
4542         /* To be sure that nobody uses thresholds */
4543         synchronize_rcu();
4544
4545         mutex_unlock(&memcg->thresholds_lock);
4546 }
4547
4548 static int mem_cgroup_oom_register_event(struct cgroup *cgrp,
4549         struct cftype *cft, struct eventfd_ctx *eventfd, const char *args)
4550 {
4551         struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
4552         struct mem_cgroup_eventfd_list *event;
4553         int type = MEMFILE_TYPE(cft->private);
4554
4555         BUG_ON(type != _OOM_TYPE);
4556         event = kmalloc(sizeof(*event), GFP_KERNEL);
4557         if (!event)
4558                 return -ENOMEM;
4559
4560         spin_lock(&memcg_oom_lock);
4561
4562         event->eventfd = eventfd;
4563         list_add(&event->list, &memcg->oom_notify);
4564
4565         /* already in OOM ? */
4566         if (atomic_read(&memcg->under_oom))
4567                 eventfd_signal(eventfd, 1);
4568         spin_unlock(&memcg_oom_lock);
4569
4570         return 0;
4571 }
4572
4573 static void mem_cgroup_oom_unregister_event(struct cgroup *cgrp,
4574         struct cftype *cft, struct eventfd_ctx *eventfd)
4575 {
4576         struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp);
4577         struct mem_cgroup_eventfd_list *ev, *tmp;
4578         int type = MEMFILE_TYPE(cft->private);
4579
4580         BUG_ON(type != _OOM_TYPE);
4581
4582         spin_lock(&memcg_oom_lock);
4583
4584         list_for_each_entry_safe(ev, tmp, &mem->oom_notify, list) {
4585                 if (ev->eventfd == eventfd) {
4586                         list_del(&ev->list);
4587                         kfree(ev);
4588                 }
4589         }
4590
4591         spin_unlock(&memcg_oom_lock);
4592 }
4593
4594 static int mem_cgroup_oom_control_read(struct cgroup *cgrp,
4595         struct cftype *cft,  struct cgroup_map_cb *cb)
4596 {
4597         struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp);
4598
4599         cb->fill(cb, "oom_kill_disable", mem->oom_kill_disable);
4600
4601         if (atomic_read(&mem->under_oom))
4602                 cb->fill(cb, "under_oom", 1);
4603         else
4604                 cb->fill(cb, "under_oom", 0);
4605         return 0;
4606 }
4607
4608 static int mem_cgroup_oom_control_write(struct cgroup *cgrp,
4609         struct cftype *cft, u64 val)
4610 {
4611         struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp);
4612         struct mem_cgroup *parent;
4613
4614         /* cannot set to root cgroup and only 0 and 1 are allowed */
4615         if (!cgrp->parent || !((val == 0) || (val == 1)))
4616                 return -EINVAL;
4617
4618         parent = mem_cgroup_from_cont(cgrp->parent);
4619
4620         cgroup_lock();
4621         /* oom-kill-disable is a flag for subhierarchy. */
4622         if ((parent->use_hierarchy) ||
4623             (mem->use_hierarchy && !list_empty(&cgrp->children))) {
4624                 cgroup_unlock();
4625                 return -EINVAL;
4626         }
4627         mem->oom_kill_disable = val;
4628         if (!val)
4629                 memcg_oom_recover(mem);
4630         cgroup_unlock();
4631         return 0;
4632 }
4633
4634 #ifdef CONFIG_NUMA
4635 static const struct file_operations mem_control_numa_stat_file_operations = {
4636         .read = seq_read,
4637         .llseek = seq_lseek,
4638         .release = single_release,
4639 };
4640
4641 static int mem_control_numa_stat_open(struct inode *unused, struct file *file)
4642 {
4643         struct cgroup *cont = file->f_dentry->d_parent->d_fsdata;
4644
4645         file->f_op = &mem_control_numa_stat_file_operations;
4646         return single_open(file, mem_control_numa_stat_show, cont);
4647 }
4648 #endif /* CONFIG_NUMA */
4649
4650 static struct cftype mem_cgroup_files[] = {
4651         {
4652                 .name = "usage_in_bytes",
4653                 .private = MEMFILE_PRIVATE(_MEM, RES_USAGE),
4654                 .read_u64 = mem_cgroup_read,
4655                 .register_event = mem_cgroup_usage_register_event,
4656                 .unregister_event = mem_cgroup_usage_unregister_event,
4657         },
4658         {
4659                 .name = "max_usage_in_bytes",
4660                 .private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE),
4661                 .trigger = mem_cgroup_reset,
4662                 .read_u64 = mem_cgroup_read,
4663         },
4664         {
4665                 .name = "limit_in_bytes",
4666                 .private = MEMFILE_PRIVATE(_MEM, RES_LIMIT),
4667                 .write_string = mem_cgroup_write,
4668                 .read_u64 = mem_cgroup_read,
4669         },
4670         {
4671                 .name = "soft_limit_in_bytes",
4672                 .private = MEMFILE_PRIVATE(_MEM, RES_SOFT_LIMIT),
4673                 .write_string = mem_cgroup_write,
4674                 .read_u64 = mem_cgroup_read,
4675         },
4676         {
4677                 .name = "failcnt",
4678                 .private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT),
4679                 .trigger = mem_cgroup_reset,
4680                 .read_u64 = mem_cgroup_read,
4681         },
4682         {
4683                 .name = "stat",
4684                 .read_map = mem_control_stat_show,
4685         },
4686         {
4687                 .name = "force_empty",
4688                 .trigger = mem_cgroup_force_empty_write,
4689         },
4690         {
4691                 .name = "use_hierarchy",
4692                 .write_u64 = mem_cgroup_hierarchy_write,
4693                 .read_u64 = mem_cgroup_hierarchy_read,
4694         },
4695         {
4696                 .name = "swappiness",
4697                 .read_u64 = mem_cgroup_swappiness_read,
4698                 .write_u64 = mem_cgroup_swappiness_write,
4699         },
4700         {
4701                 .name = "move_charge_at_immigrate",
4702                 .read_u64 = mem_cgroup_move_charge_read,
4703                 .write_u64 = mem_cgroup_move_charge_write,
4704         },
4705         {
4706                 .name = "oom_control",
4707                 .read_map = mem_cgroup_oom_control_read,
4708                 .write_u64 = mem_cgroup_oom_control_write,
4709                 .register_event = mem_cgroup_oom_register_event,
4710                 .unregister_event = mem_cgroup_oom_unregister_event,
4711                 .private = MEMFILE_PRIVATE(_OOM_TYPE, OOM_CONTROL),
4712         },
4713 #ifdef CONFIG_NUMA
4714         {
4715                 .name = "numa_stat",
4716                 .open = mem_control_numa_stat_open,
4717                 .mode = S_IRUGO,
4718         },
4719 #endif
4720 };
4721
4722 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
4723 static struct cftype memsw_cgroup_files[] = {
4724         {
4725                 .name = "memsw.usage_in_bytes",
4726                 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE),
4727                 .read_u64 = mem_cgroup_read,
4728                 .register_event = mem_cgroup_usage_register_event,
4729                 .unregister_event = mem_cgroup_usage_unregister_event,
4730         },
4731         {
4732                 .name = "memsw.max_usage_in_bytes",
4733                 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE),
4734                 .trigger = mem_cgroup_reset,
4735                 .read_u64 = mem_cgroup_read,
4736         },
4737         {
4738                 .name = "memsw.limit_in_bytes",
4739                 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT),
4740                 .write_string = mem_cgroup_write,
4741                 .read_u64 = mem_cgroup_read,
4742         },
4743         {
4744                 .name = "memsw.failcnt",
4745                 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT),
4746                 .trigger = mem_cgroup_reset,
4747                 .read_u64 = mem_cgroup_read,
4748         },
4749 };
4750
4751 static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss)
4752 {
4753         if (!do_swap_account)
4754                 return 0;
4755         return cgroup_add_files(cont, ss, memsw_cgroup_files,
4756                                 ARRAY_SIZE(memsw_cgroup_files));
4757 };
4758 #else
4759 static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss)
4760 {
4761         return 0;
4762 }
4763 #endif
4764
4765 static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
4766 {
4767         struct mem_cgroup_per_node *pn;
4768         struct mem_cgroup_per_zone *mz;
4769         enum lru_list l;
4770         int zone, tmp = node;
4771         /*
4772          * This routine is called against possible nodes.
4773          * But it's BUG to call kmalloc() against offline node.
4774          *
4775          * TODO: this routine can waste much memory for nodes which will
4776          *       never be onlined. It's better to use memory hotplug callback
4777          *       function.
4778          */
4779         if (!node_state(node, N_NORMAL_MEMORY))
4780                 tmp = -1;
4781         pn = kzalloc_node(sizeof(*pn), GFP_KERNEL, tmp);
4782         if (!pn)
4783                 return 1;
4784
4785         mem->info.nodeinfo[node] = pn;
4786         for (zone = 0; zone < MAX_NR_ZONES; zone++) {
4787                 mz = &pn->zoneinfo[zone];
4788                 for_each_lru(l)
4789                         INIT_LIST_HEAD(&mz->lists[l]);
4790                 mz->usage_in_excess = 0;
4791                 mz->on_tree = false;
4792                 mz->mem = mem;
4793         }
4794         return 0;
4795 }
4796
4797 static void free_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
4798 {
4799         kfree(mem->info.nodeinfo[node]);
4800 }
4801
4802 static struct mem_cgroup *mem_cgroup_alloc(void)
4803 {
4804         struct mem_cgroup *mem;
4805         int size = sizeof(struct mem_cgroup);
4806
4807         /* Can be very big if MAX_NUMNODES is very big */
4808         if (size < PAGE_SIZE)
4809                 mem = kzalloc(size, GFP_KERNEL);
4810         else
4811                 mem = vzalloc(size);
4812
4813         if (!mem)
4814                 return NULL;
4815
4816         mem->stat = alloc_percpu(struct mem_cgroup_stat_cpu);
4817         if (!mem->stat)
4818                 goto out_free;
4819         spin_lock_init(&mem->pcp_counter_lock);
4820         return mem;
4821
4822 out_free:
4823         if (size < PAGE_SIZE)
4824                 kfree(mem);
4825         else
4826                 vfree(mem);
4827         return NULL;
4828 }
4829
4830 /*
4831  * At destroying mem_cgroup, references from swap_cgroup can remain.
4832  * (scanning all at force_empty is too costly...)
4833  *
4834  * Instead of clearing all references at force_empty, we remember
4835  * the number of reference from swap_cgroup and free mem_cgroup when
4836  * it goes down to 0.
4837  *
4838  * Removal of cgroup itself succeeds regardless of refs from swap.
4839  */
4840
4841 static void __mem_cgroup_free(struct mem_cgroup *mem)
4842 {
4843         int node;
4844
4845         mem_cgroup_remove_from_trees(mem);
4846         free_css_id(&mem_cgroup_subsys, &mem->css);
4847
4848         for_each_node_state(node, N_POSSIBLE)
4849                 free_mem_cgroup_per_zone_info(mem, node);
4850
4851         free_percpu(mem->stat);
4852         if (sizeof(struct mem_cgroup) < PAGE_SIZE)
4853                 kfree(mem);
4854         else
4855                 vfree(mem);
4856 }
4857
4858 static void mem_cgroup_get(struct mem_cgroup *mem)
4859 {
4860         atomic_inc(&mem->refcnt);
4861 }
4862
4863 static void __mem_cgroup_put(struct mem_cgroup *mem, int count)
4864 {
4865         if (atomic_sub_and_test(count, &mem->refcnt)) {
4866                 struct mem_cgroup *parent = parent_mem_cgroup(mem);
4867                 __mem_cgroup_free(mem);
4868                 if (parent)
4869                         mem_cgroup_put(parent);
4870         }
4871 }
4872
4873 static void mem_cgroup_put(struct mem_cgroup *mem)
4874 {
4875         __mem_cgroup_put(mem, 1);
4876 }
4877
4878 /*
4879  * Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled.
4880  */
4881 static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem)
4882 {
4883         if (!mem->res.parent)
4884                 return NULL;
4885         return mem_cgroup_from_res_counter(mem->res.parent, res);
4886 }
4887
4888 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
4889 static void __init enable_swap_cgroup(void)
4890 {
4891         if (!mem_cgroup_disabled() && really_do_swap_account)
4892                 do_swap_account = 1;
4893 }
4894 #else
4895 static void __init enable_swap_cgroup(void)
4896 {
4897 }
4898 #endif
4899
4900 static int mem_cgroup_soft_limit_tree_init(void)
4901 {
4902         struct mem_cgroup_tree_per_node *rtpn;
4903         struct mem_cgroup_tree_per_zone *rtpz;
4904         int tmp, node, zone;
4905
4906         for_each_node_state(node, N_POSSIBLE) {
4907                 tmp = node;
4908                 if (!node_state(node, N_NORMAL_MEMORY))
4909                         tmp = -1;
4910                 rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL, tmp);
4911                 if (!rtpn)
4912                         return 1;
4913
4914                 soft_limit_tree.rb_tree_per_node[node] = rtpn;
4915
4916                 for (zone = 0; zone < MAX_NR_ZONES; zone++) {
4917                         rtpz = &rtpn->rb_tree_per_zone[zone];
4918                         rtpz->rb_root = RB_ROOT;
4919                         spin_lock_init(&rtpz->lock);
4920                 }
4921         }
4922         return 0;
4923 }
4924
4925 static struct cgroup_subsys_state * __ref
4926 mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
4927 {
4928         struct mem_cgroup *mem, *parent;
4929         long error = -ENOMEM;
4930         int node;
4931
4932         mem = mem_cgroup_alloc();
4933         if (!mem)
4934                 return ERR_PTR(error);
4935
4936         for_each_node_state(node, N_POSSIBLE)
4937                 if (alloc_mem_cgroup_per_zone_info(mem, node))
4938                         goto free_out;
4939
4940         /* root ? */
4941         if (cont->parent == NULL) {
4942                 int cpu;
4943                 enable_swap_cgroup();
4944                 parent = NULL;
4945                 if (mem_cgroup_soft_limit_tree_init())
4946                         goto free_out;
4947                 root_mem_cgroup = mem;
4948                 for_each_possible_cpu(cpu) {
4949                         struct memcg_stock_pcp *stock =
4950                                                 &per_cpu(memcg_stock, cpu);
4951                         INIT_WORK(&stock->work, drain_local_stock);
4952                 }
4953                 hotcpu_notifier(memcg_cpu_hotplug_callback, 0);
4954         } else {
4955                 parent = mem_cgroup_from_cont(cont->parent);
4956                 mem->use_hierarchy = parent->use_hierarchy;
4957                 mem->oom_kill_disable = parent->oom_kill_disable;
4958         }
4959
4960         if (parent && parent->use_hierarchy) {
4961                 res_counter_init(&mem->res, &parent->res);
4962                 res_counter_init(&mem->memsw, &parent->memsw);
4963                 /*
4964                  * We increment refcnt of the parent to ensure that we can
4965                  * safely access it on res_counter_charge/uncharge.
4966                  * This refcnt will be decremented when freeing this
4967                  * mem_cgroup(see mem_cgroup_put).
4968                  */
4969                 mem_cgroup_get(parent);
4970         } else {
4971                 res_counter_init(&mem->res, NULL);
4972                 res_counter_init(&mem->memsw, NULL);
4973         }
4974         mem->last_scanned_child = 0;
4975         mem->last_scanned_node = MAX_NUMNODES;
4976         INIT_LIST_HEAD(&mem->oom_notify);
4977
4978         if (parent)
4979                 mem->swappiness = mem_cgroup_swappiness(parent);
4980         atomic_set(&mem->refcnt, 1);
4981         mem->move_charge_at_immigrate = 0;
4982         mutex_init(&mem->thresholds_lock);
4983         return &mem->css;
4984 free_out:
4985         __mem_cgroup_free(mem);
4986         return ERR_PTR(error);
4987 }
4988
4989 static int mem_cgroup_pre_destroy(struct cgroup_subsys *ss,
4990                                         struct cgroup *cont)
4991 {
4992         struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
4993
4994         return mem_cgroup_force_empty(mem, false);
4995 }
4996
4997 static void mem_cgroup_destroy(struct cgroup_subsys *ss,
4998                                 struct cgroup *cont)
4999 {
5000         struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
5001
5002         mem_cgroup_put(mem);
5003 }
5004
5005 static int mem_cgroup_populate(struct cgroup_subsys *ss,
5006                                 struct cgroup *cont)
5007 {
5008         int ret;
5009
5010         ret = cgroup_add_files(cont, ss, mem_cgroup_files,
5011                                 ARRAY_SIZE(mem_cgroup_files));
5012
5013         if (!ret)
5014                 ret = register_memsw_files(cont, ss);
5015         return ret;
5016 }
5017
5018 #ifdef CONFIG_MMU
5019 /* Handlers for move charge at task migration. */
5020 #define PRECHARGE_COUNT_AT_ONCE 256
5021 static int mem_cgroup_do_precharge(unsigned long count)
5022 {
5023         int ret = 0;
5024         int batch_count = PRECHARGE_COUNT_AT_ONCE;
5025         struct mem_cgroup *mem = mc.to;
5026
5027         if (mem_cgroup_is_root(mem)) {
5028                 mc.precharge += count;
5029                 /* we don't need css_get for root */
5030                 return ret;
5031         }
5032         /* try to charge at once */
5033         if (count > 1) {
5034                 struct res_counter *dummy;
5035                 /*
5036                  * "mem" cannot be under rmdir() because we've already checked
5037                  * by cgroup_lock_live_cgroup() that it is not removed and we
5038                  * are still under the same cgroup_mutex. So we can postpone
5039                  * css_get().
5040                  */
5041                 if (res_counter_charge(&mem->res, PAGE_SIZE * count, &dummy))
5042                         goto one_by_one;
5043                 if (do_swap_account && res_counter_charge(&mem->memsw,
5044                                                 PAGE_SIZE * count, &dummy)) {
5045                         res_counter_uncharge(&mem->res, PAGE_SIZE * count);
5046                         goto one_by_one;
5047                 }
5048                 mc.precharge += count;
5049                 return ret;
5050         }
5051 one_by_one:
5052         /* fall back to one by one charge */
5053         while (count--) {
5054                 if (signal_pending(current)) {
5055                         ret = -EINTR;
5056                         break;
5057                 }
5058                 if (!batch_count--) {
5059                         batch_count = PRECHARGE_COUNT_AT_ONCE;
5060                         cond_resched();
5061                 }
5062                 ret = __mem_cgroup_try_charge(NULL, GFP_KERNEL, 1, &mem, false);
5063                 if (ret || !mem)
5064                         /* mem_cgroup_clear_mc() will do uncharge later */
5065                         return -ENOMEM;
5066                 mc.precharge++;
5067         }
5068         return ret;
5069 }
5070
5071 /**
5072  * is_target_pte_for_mc - check a pte whether it is valid for move charge
5073  * @vma: the vma the pte to be checked belongs
5074  * @addr: the address corresponding to the pte to be checked
5075  * @ptent: the pte to be checked
5076  * @target: the pointer the target page or swap ent will be stored(can be NULL)
5077  *
5078  * Returns
5079  *   0(MC_TARGET_NONE): if the pte is not a target for move charge.
5080  *   1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for
5081  *     move charge. if @target is not NULL, the page is stored in target->page
5082  *     with extra refcnt got(Callers should handle it).
5083  *   2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a
5084  *     target for charge migration. if @target is not NULL, the entry is stored
5085  *     in target->ent.
5086  *
5087  * Called with pte lock held.
5088  */
5089 union mc_target {
5090         struct page     *page;
5091         swp_entry_t     ent;
5092 };
5093
5094 enum mc_target_type {
5095         MC_TARGET_NONE, /* not used */
5096         MC_TARGET_PAGE,
5097         MC_TARGET_SWAP,
5098 };
5099
5100 static struct page *mc_handle_present_pte(struct vm_area_struct *vma,
5101                                                 unsigned long addr, pte_t ptent)
5102 {
5103         struct page *page = vm_normal_page(vma, addr, ptent);
5104
5105         if (!page || !page_mapped(page))
5106                 return NULL;
5107         if (PageAnon(page)) {
5108                 /* we don't move shared anon */
5109                 if (!move_anon() || page_mapcount(page) > 2)
5110                         return NULL;
5111         } else if (!move_file())
5112                 /* we ignore mapcount for file pages */
5113                 return NULL;
5114         if (!get_page_unless_zero(page))
5115                 return NULL;
5116
5117         return page;
5118 }
5119
5120 static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
5121                         unsigned long addr, pte_t ptent, swp_entry_t *entry)
5122 {
5123         int usage_count;
5124         struct page *page = NULL;
5125         swp_entry_t ent = pte_to_swp_entry(ptent);
5126
5127         if (!move_anon() || non_swap_entry(ent))
5128                 return NULL;
5129         usage_count = mem_cgroup_count_swap_user(ent, &page);
5130         if (usage_count > 1) { /* we don't move shared anon */
5131                 if (page)
5132                         put_page(page);
5133                 return NULL;
5134         }
5135         if (do_swap_account)
5136                 entry->val = ent.val;
5137
5138         return page;
5139 }
5140
5141 static struct page *mc_handle_file_pte(struct vm_area_struct *vma,
5142                         unsigned long addr, pte_t ptent, swp_entry_t *entry)
5143 {
5144         struct page *page = NULL;
5145         struct inode *inode;
5146         struct address_space *mapping;
5147         pgoff_t pgoff;
5148
5149         if (!vma->vm_file) /* anonymous vma */
5150                 return NULL;
5151         if (!move_file())
5152                 return NULL;
5153
5154         inode = vma->vm_file->f_path.dentry->d_inode;
5155         mapping = vma->vm_file->f_mapping;
5156         if (pte_none(ptent))
5157                 pgoff = linear_page_index(vma, addr);
5158         else /* pte_file(ptent) is true */
5159                 pgoff = pte_to_pgoff(ptent);
5160
5161         /* page is moved even if it's not RSS of this task(page-faulted). */
5162         page = find_get_page(mapping, pgoff);
5163
5164 #ifdef CONFIG_SWAP
5165         /* shmem/tmpfs may report page out on swap: account for that too. */
5166         if (radix_tree_exceptional_entry(page)) {
5167                 swp_entry_t swap = radix_to_swp_entry(page);
5168                 if (do_swap_account)
5169                         *entry = swap;
5170                 page = find_get_page(&swapper_space, swap.val);
5171         }
5172 #endif
5173         return page;
5174 }
5175
5176 static int is_target_pte_for_mc(struct vm_area_struct *vma,
5177                 unsigned long addr, pte_t ptent, union mc_target *target)
5178 {
5179         struct page *page = NULL;
5180         struct page_cgroup *pc;
5181         int ret = 0;
5182         swp_entry_t ent = { .val = 0 };
5183
5184         if (pte_present(ptent))
5185                 page = mc_handle_present_pte(vma, addr, ptent);
5186         else if (is_swap_pte(ptent))
5187                 page = mc_handle_swap_pte(vma, addr, ptent, &ent);
5188         else if (pte_none(ptent) || pte_file(ptent))
5189                 page = mc_handle_file_pte(vma, addr, ptent, &ent);
5190
5191         if (!page && !ent.val)
5192                 return 0;
5193         if (page) {
5194                 pc = lookup_page_cgroup(page);
5195                 /*
5196                  * Do only loose check w/o page_cgroup lock.
5197                  * mem_cgroup_move_account() checks the pc is valid or not under
5198                  * the lock.
5199                  */
5200                 if (PageCgroupUsed(pc) && pc->mem_cgroup == mc.from) {
5201                         ret = MC_TARGET_PAGE;
5202                         if (target)
5203                                 target->page = page;
5204                 }
5205                 if (!ret || !target)
5206                         put_page(page);
5207         }
5208         /* There is a swap entry and a page doesn't exist or isn't charged */
5209         if (ent.val && !ret &&
5210                         css_id(&mc.from->css) == lookup_swap_cgroup(ent)) {
5211                 ret = MC_TARGET_SWAP;
5212                 if (target)
5213                         target->ent = ent;
5214         }
5215         return ret;
5216 }
5217
5218 static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd,
5219                                         unsigned long addr, unsigned long end,
5220                                         struct mm_walk *walk)
5221 {
5222         struct vm_area_struct *vma = walk->private;
5223         pte_t *pte;
5224         spinlock_t *ptl;
5225
5226         split_huge_page_pmd(walk->mm, pmd);
5227
5228         pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
5229         for (; addr != end; pte++, addr += PAGE_SIZE)
5230                 if (is_target_pte_for_mc(vma, addr, *pte, NULL))
5231                         mc.precharge++; /* increment precharge temporarily */
5232         pte_unmap_unlock(pte - 1, ptl);
5233         cond_resched();
5234
5235         return 0;
5236 }
5237
5238 static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm)
5239 {
5240         unsigned long precharge;
5241         struct vm_area_struct *vma;
5242
5243         down_read(&mm->mmap_sem);
5244         for (vma = mm->mmap; vma; vma = vma->vm_next) {
5245                 struct mm_walk mem_cgroup_count_precharge_walk = {
5246                         .pmd_entry = mem_cgroup_count_precharge_pte_range,
5247                         .mm = mm,
5248                         .private = vma,
5249                 };
5250                 if (is_vm_hugetlb_page(vma))
5251                         continue;
5252                 walk_page_range(vma->vm_start, vma->vm_end,
5253                                         &mem_cgroup_count_precharge_walk);
5254         }
5255         up_read(&mm->mmap_sem);
5256
5257         precharge = mc.precharge;
5258         mc.precharge = 0;
5259
5260         return precharge;
5261 }
5262
5263 static int mem_cgroup_precharge_mc(struct mm_struct *mm)
5264 {
5265         unsigned long precharge = mem_cgroup_count_precharge(mm);
5266
5267         VM_BUG_ON(mc.moving_task);
5268         mc.moving_task = current;
5269         return mem_cgroup_do_precharge(precharge);
5270 }
5271
5272 /* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */
5273 static void __mem_cgroup_clear_mc(void)
5274 {
5275         struct mem_cgroup *from = mc.from;
5276         struct mem_cgroup *to = mc.to;
5277
5278         /* we must uncharge all the leftover precharges from mc.to */
5279         if (mc.precharge) {
5280                 __mem_cgroup_cancel_charge(mc.to, mc.precharge);
5281                 mc.precharge = 0;
5282         }
5283         /*
5284          * we didn't uncharge from mc.from at mem_cgroup_move_account(), so
5285          * we must uncharge here.
5286          */
5287         if (mc.moved_charge) {
5288                 __mem_cgroup_cancel_charge(mc.from, mc.moved_charge);
5289                 mc.moved_charge = 0;
5290         }
5291         /* we must fixup refcnts and charges */
5292         if (mc.moved_swap) {
5293                 /* uncharge swap account from the old cgroup */
5294                 if (!mem_cgroup_is_root(mc.from))
5295                         res_counter_uncharge(&mc.from->memsw,
5296                                                 PAGE_SIZE * mc.moved_swap);
5297                 __mem_cgroup_put(mc.from, mc.moved_swap);
5298
5299                 if (!mem_cgroup_is_root(mc.to)) {
5300                         /*
5301                          * we charged both to->res and to->memsw, so we should
5302                          * uncharge to->res.
5303                          */
5304                         res_counter_uncharge(&mc.to->res,
5305                                                 PAGE_SIZE * mc.moved_swap);
5306                 }
5307                 /* we've already done mem_cgroup_get(mc.to) */
5308                 mc.moved_swap = 0;
5309         }
5310         memcg_oom_recover(from);
5311         memcg_oom_recover(to);
5312         wake_up_all(&mc.waitq);
5313 }
5314
5315 static void mem_cgroup_clear_mc(void)
5316 {
5317         struct mem_cgroup *from = mc.from;
5318
5319         /*
5320          * we must clear moving_task before waking up waiters at the end of
5321          * task migration.
5322          */
5323         mc.moving_task = NULL;
5324         __mem_cgroup_clear_mc();
5325         spin_lock(&mc.lock);
5326         mc.from = NULL;
5327         mc.to = NULL;
5328         spin_unlock(&mc.lock);
5329         mem_cgroup_end_move(from);
5330 }
5331
5332 static int mem_cgroup_can_attach(struct cgroup_subsys *ss,
5333                                 struct cgroup *cgroup,
5334                                 struct task_struct *p)
5335 {
5336         int ret = 0;
5337         struct mem_cgroup *mem = mem_cgroup_from_cont(cgroup);
5338
5339         if (mem->move_charge_at_immigrate) {
5340                 struct mm_struct *mm;
5341                 struct mem_cgroup *from = mem_cgroup_from_task(p);
5342
5343                 VM_BUG_ON(from == mem);
5344
5345                 mm = get_task_mm(p);
5346                 if (!mm)
5347                         return 0;
5348                 /* We move charges only when we move a owner of the mm */
5349                 if (mm->owner == p) {
5350                         VM_BUG_ON(mc.from);
5351                         VM_BUG_ON(mc.to);
5352                         VM_BUG_ON(mc.precharge);
5353                         VM_BUG_ON(mc.moved_charge);
5354                         VM_BUG_ON(mc.moved_swap);
5355                         mem_cgroup_start_move(from);
5356                         spin_lock(&mc.lock);
5357                         mc.from = from;
5358                         mc.to = mem;
5359                         spin_unlock(&mc.lock);
5360                         /* We set mc.moving_task later */
5361
5362                         ret = mem_cgroup_precharge_mc(mm);
5363                         if (ret)
5364                                 mem_cgroup_clear_mc();
5365                 }
5366                 mmput(mm);
5367         }
5368         return ret;
5369 }
5370
5371 static void mem_cgroup_cancel_attach(struct cgroup_subsys *ss,
5372                                 struct cgroup *cgroup,
5373                                 struct task_struct *p)
5374 {
5375         mem_cgroup_clear_mc();
5376 }
5377
5378 static int mem_cgroup_move_charge_pte_range(pmd_t *pmd,
5379                                 unsigned long addr, unsigned long end,
5380                                 struct mm_walk *walk)
5381 {
5382         int ret = 0;
5383         struct vm_area_struct *vma = walk->private;
5384         pte_t *pte;
5385         spinlock_t *ptl;
5386
5387         split_huge_page_pmd(walk->mm, pmd);
5388 retry:
5389         pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
5390         for (; addr != end; addr += PAGE_SIZE) {
5391                 pte_t ptent = *(pte++);
5392                 union mc_target target;
5393                 int type;
5394                 struct page *page;
5395                 struct page_cgroup *pc;
5396                 swp_entry_t ent;
5397
5398                 if (!mc.precharge)
5399                         break;
5400
5401                 type = is_target_pte_for_mc(vma, addr, ptent, &target);
5402                 switch (type) {
5403                 case MC_TARGET_PAGE:
5404                         page = target.page;
5405                         if (isolate_lru_page(page))
5406                                 goto put;
5407                         pc = lookup_page_cgroup(page);
5408                         if (!mem_cgroup_move_account(page, 1, pc,
5409                                                      mc.from, mc.to, false)) {
5410                                 mc.precharge--;
5411                                 /* we uncharge from mc.from later. */
5412                                 mc.moved_charge++;
5413                         }
5414                         putback_lru_page(page);
5415 put:                    /* is_target_pte_for_mc() gets the page */
5416                         put_page(page);
5417                         break;
5418                 case MC_TARGET_SWAP:
5419                         ent = target.ent;
5420                         if (!mem_cgroup_move_swap_account(ent,
5421                                                 mc.from, mc.to, false)) {
5422                                 mc.precharge--;
5423                                 /* we fixup refcnts and charges later. */
5424                                 mc.moved_swap++;
5425                         }
5426                         break;
5427                 default:
5428                         break;
5429                 }
5430         }
5431         pte_unmap_unlock(pte - 1, ptl);
5432         cond_resched();
5433
5434         if (addr != end) {
5435                 /*
5436                  * We have consumed all precharges we got in can_attach().
5437                  * We try charge one by one, but don't do any additional
5438                  * charges to mc.to if we have failed in charge once in attach()
5439                  * phase.
5440                  */
5441                 ret = mem_cgroup_do_precharge(1);
5442                 if (!ret)
5443                         goto retry;
5444         }
5445
5446         return ret;
5447 }
5448
5449 static void mem_cgroup_move_charge(struct mm_struct *mm)
5450 {
5451         struct vm_area_struct *vma;
5452
5453         lru_add_drain_all();
5454 retry:
5455         if (unlikely(!down_read_trylock(&mm->mmap_sem))) {
5456                 /*
5457                  * Someone who are holding the mmap_sem might be waiting in
5458                  * waitq. So we cancel all extra charges, wake up all waiters,
5459                  * and retry. Because we cancel precharges, we might not be able
5460                  * to move enough charges, but moving charge is a best-effort
5461                  * feature anyway, so it wouldn't be a big problem.
5462                  */
5463                 __mem_cgroup_clear_mc();
5464                 cond_resched();
5465                 goto retry;
5466         }
5467         for (vma = mm->mmap; vma; vma = vma->vm_next) {
5468                 int ret;
5469                 struct mm_walk mem_cgroup_move_charge_walk = {
5470                         .pmd_entry = mem_cgroup_move_charge_pte_range,
5471                         .mm = mm,
5472                         .private = vma,
5473                 };
5474                 if (is_vm_hugetlb_page(vma))
5475                         continue;
5476                 ret = walk_page_range(vma->vm_start, vma->vm_end,
5477                                                 &mem_cgroup_move_charge_walk);
5478                 if (ret)
5479                         /*
5480                          * means we have consumed all precharges and failed in
5481                          * doing additional charge. Just abandon here.
5482                          */
5483                         break;
5484         }
5485         up_read(&mm->mmap_sem);
5486 }
5487
5488 static void mem_cgroup_move_task(struct cgroup_subsys *ss,
5489                                 struct cgroup *cont,
5490                                 struct cgroup *old_cont,
5491                                 struct task_struct *p)
5492 {
5493         struct mm_struct *mm = get_task_mm(p);
5494
5495         if (mm) {
5496                 if (mc.to)
5497                         mem_cgroup_move_charge(mm);
5498                 put_swap_token(mm);
5499                 mmput(mm);
5500         }
5501         if (mc.to)
5502                 mem_cgroup_clear_mc();
5503 }
5504 #else   /* !CONFIG_MMU */
5505 static int mem_cgroup_can_attach(struct cgroup_subsys *ss,
5506                                 struct cgroup *cgroup,
5507                                 struct task_struct *p)
5508 {
5509         return 0;
5510 }
5511 static void mem_cgroup_cancel_attach(struct cgroup_subsys *ss,
5512                                 struct cgroup *cgroup,
5513                                 struct task_struct *p)
5514 {
5515 }
5516 static void mem_cgroup_move_task(struct cgroup_subsys *ss,
5517                                 struct cgroup *cont,
5518                                 struct cgroup *old_cont,
5519                                 struct task_struct *p)
5520 {
5521 }
5522 #endif
5523
5524 struct cgroup_subsys mem_cgroup_subsys = {
5525         .name = "memory",
5526         .subsys_id = mem_cgroup_subsys_id,
5527         .create = mem_cgroup_create,
5528         .pre_destroy = mem_cgroup_pre_destroy,
5529         .destroy = mem_cgroup_destroy,
5530         .populate = mem_cgroup_populate,
5531         .can_attach = mem_cgroup_can_attach,
5532         .cancel_attach = mem_cgroup_cancel_attach,
5533         .attach = mem_cgroup_move_task,
5534         .early_init = 0,
5535         .use_id = 1,
5536 };
5537
5538 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
5539 static int __init enable_swap_account(char *s)
5540 {
5541         /* consider enabled if no parameter or 1 is given */
5542         if (!strcmp(s, "1"))
5543                 really_do_swap_account = 1;
5544         else if (!strcmp(s, "0"))
5545                 really_do_swap_account = 0;
5546         return 1;
5547 }
5548 __setup("swapaccount=", enable_swap_account);
5549
5550 #endif