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cgroup: remove sane_behavior support on non-default hierarchies
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8cdea7c0
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1/* memcontrol.c - Memory Controller
2 *
3 * Copyright IBM Corporation, 2007
4 * Author Balbir Singh <balbir@linux.vnet.ibm.com>
5 *
78fb7466
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6 * Copyright 2007 OpenVZ SWsoft Inc
7 * Author: Pavel Emelianov <xemul@openvz.org>
8 *
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9 * Memory thresholds
10 * Copyright (C) 2009 Nokia Corporation
11 * Author: Kirill A. Shutemov
12 *
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13 * Kernel Memory Controller
14 * Copyright (C) 2012 Parallels Inc. and Google Inc.
15 * Authors: Glauber Costa and Suleiman Souhlal
16 *
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17 * This program is free software; you can redistribute it and/or modify
18 * it under the terms of the GNU General Public License as published by
19 * the Free Software Foundation; either version 2 of the License, or
20 * (at your option) any later version.
21 *
22 * This program is distributed in the hope that it will be useful,
23 * but WITHOUT ANY WARRANTY; without even the implied warranty of
24 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
25 * GNU General Public License for more details.
26 */
27
28#include <linux/res_counter.h>
29#include <linux/memcontrol.h>
30#include <linux/cgroup.h>
78fb7466 31#include <linux/mm.h>
4ffef5fe 32#include <linux/hugetlb.h>
d13d1443 33#include <linux/pagemap.h>
d52aa412 34#include <linux/smp.h>
8a9f3ccd 35#include <linux/page-flags.h>
66e1707b 36#include <linux/backing-dev.h>
8a9f3ccd
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37#include <linux/bit_spinlock.h>
38#include <linux/rcupdate.h>
e222432b 39#include <linux/limits.h>
b9e15baf 40#include <linux/export.h>
8c7c6e34 41#include <linux/mutex.h>
bb4cc1a8 42#include <linux/rbtree.h>
b6ac57d5 43#include <linux/slab.h>
66e1707b 44#include <linux/swap.h>
02491447 45#include <linux/swapops.h>
66e1707b 46#include <linux/spinlock.h>
2e72b634 47#include <linux/eventfd.h>
79bd9814 48#include <linux/poll.h>
2e72b634 49#include <linux/sort.h>
66e1707b 50#include <linux/fs.h>
d2ceb9b7 51#include <linux/seq_file.h>
70ddf637 52#include <linux/vmpressure.h>
b69408e8 53#include <linux/mm_inline.h>
52d4b9ac 54#include <linux/page_cgroup.h>
cdec2e42 55#include <linux/cpu.h>
158e0a2d 56#include <linux/oom.h>
0056f4e6 57#include <linux/lockdep.h>
79bd9814 58#include <linux/file.h>
08e552c6 59#include "internal.h"
d1a4c0b3 60#include <net/sock.h>
4bd2c1ee 61#include <net/ip.h>
d1a4c0b3 62#include <net/tcp_memcontrol.h>
f35c3a8e 63#include "slab.h"
8cdea7c0 64
8697d331
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65#include <asm/uaccess.h>
66
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67#include <trace/events/vmscan.h>
68
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69struct cgroup_subsys memory_cgrp_subsys __read_mostly;
70EXPORT_SYMBOL(memory_cgrp_subsys);
68ae564b 71
a181b0e8 72#define MEM_CGROUP_RECLAIM_RETRIES 5
6bbda35c 73static struct mem_cgroup *root_mem_cgroup __read_mostly;
8cdea7c0 74
c255a458 75#ifdef CONFIG_MEMCG_SWAP
338c8431 76/* Turned on only when memory cgroup is enabled && really_do_swap_account = 1 */
c077719b 77int do_swap_account __read_mostly;
a42c390c
MH
78
79/* for remember boot option*/
c255a458 80#ifdef CONFIG_MEMCG_SWAP_ENABLED
a42c390c
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81static int really_do_swap_account __initdata = 1;
82#else
ada4ba59 83static int really_do_swap_account __initdata;
a42c390c
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84#endif
85
c077719b 86#else
a0db00fc 87#define do_swap_account 0
c077719b
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88#endif
89
90
af7c4b0e
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91static const char * const mem_cgroup_stat_names[] = {
92 "cache",
93 "rss",
b070e65c 94 "rss_huge",
af7c4b0e 95 "mapped_file",
3ea67d06 96 "writeback",
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97 "swap",
98};
99
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100enum mem_cgroup_events_index {
101 MEM_CGROUP_EVENTS_PGPGIN, /* # of pages paged in */
102 MEM_CGROUP_EVENTS_PGPGOUT, /* # of pages paged out */
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103 MEM_CGROUP_EVENTS_PGFAULT, /* # of page-faults */
104 MEM_CGROUP_EVENTS_PGMAJFAULT, /* # of major page-faults */
e9f8974f
JW
105 MEM_CGROUP_EVENTS_NSTATS,
106};
af7c4b0e
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107
108static const char * const mem_cgroup_events_names[] = {
109 "pgpgin",
110 "pgpgout",
111 "pgfault",
112 "pgmajfault",
113};
114
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115static const char * const mem_cgroup_lru_names[] = {
116 "inactive_anon",
117 "active_anon",
118 "inactive_file",
119 "active_file",
120 "unevictable",
121};
122
7a159cc9
JW
123/*
124 * Per memcg event counter is incremented at every pagein/pageout. With THP,
125 * it will be incremated by the number of pages. This counter is used for
126 * for trigger some periodic events. This is straightforward and better
127 * than using jiffies etc. to handle periodic memcg event.
128 */
129enum mem_cgroup_events_target {
130 MEM_CGROUP_TARGET_THRESH,
bb4cc1a8 131 MEM_CGROUP_TARGET_SOFTLIMIT,
453a9bf3 132 MEM_CGROUP_TARGET_NUMAINFO,
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133 MEM_CGROUP_NTARGETS,
134};
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135#define THRESHOLDS_EVENTS_TARGET 128
136#define SOFTLIMIT_EVENTS_TARGET 1024
137#define NUMAINFO_EVENTS_TARGET 1024
e9f8974f 138
d52aa412 139struct mem_cgroup_stat_cpu {
7a159cc9 140 long count[MEM_CGROUP_STAT_NSTATS];
e9f8974f 141 unsigned long events[MEM_CGROUP_EVENTS_NSTATS];
13114716 142 unsigned long nr_page_events;
7a159cc9 143 unsigned long targets[MEM_CGROUP_NTARGETS];
d52aa412
KH
144};
145
527a5ec9 146struct mem_cgroup_reclaim_iter {
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MH
147 /*
148 * last scanned hierarchy member. Valid only if last_dead_count
149 * matches memcg->dead_count of the hierarchy root group.
150 */
542f85f9 151 struct mem_cgroup *last_visited;
d2ab70aa 152 int last_dead_count;
5f578161 153
527a5ec9
JW
154 /* scan generation, increased every round-trip */
155 unsigned int generation;
156};
157
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KH
158/*
159 * per-zone information in memory controller.
160 */
6d12e2d8 161struct mem_cgroup_per_zone {
6290df54 162 struct lruvec lruvec;
1eb49272 163 unsigned long lru_size[NR_LRU_LISTS];
3e2f41f1 164
527a5ec9
JW
165 struct mem_cgroup_reclaim_iter reclaim_iter[DEF_PRIORITY + 1];
166
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AM
167 struct rb_node tree_node; /* RB tree node */
168 unsigned long long usage_in_excess;/* Set to the value by which */
169 /* the soft limit is exceeded*/
170 bool on_tree;
d79154bb 171 struct mem_cgroup *memcg; /* Back pointer, we cannot */
4e416953 172 /* use container_of */
6d12e2d8 173};
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174
175struct mem_cgroup_per_node {
176 struct mem_cgroup_per_zone zoneinfo[MAX_NR_ZONES];
177};
178
bb4cc1a8
AM
179/*
180 * Cgroups above their limits are maintained in a RB-Tree, independent of
181 * their hierarchy representation
182 */
183
184struct mem_cgroup_tree_per_zone {
185 struct rb_root rb_root;
186 spinlock_t lock;
187};
188
189struct mem_cgroup_tree_per_node {
190 struct mem_cgroup_tree_per_zone rb_tree_per_zone[MAX_NR_ZONES];
191};
192
193struct mem_cgroup_tree {
194 struct mem_cgroup_tree_per_node *rb_tree_per_node[MAX_NUMNODES];
195};
196
197static struct mem_cgroup_tree soft_limit_tree __read_mostly;
198
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199struct mem_cgroup_threshold {
200 struct eventfd_ctx *eventfd;
201 u64 threshold;
202};
203
9490ff27 204/* For threshold */
2e72b634 205struct mem_cgroup_threshold_ary {
748dad36 206 /* An array index points to threshold just below or equal to usage. */
5407a562 207 int current_threshold;
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208 /* Size of entries[] */
209 unsigned int size;
210 /* Array of thresholds */
211 struct mem_cgroup_threshold entries[0];
212};
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213
214struct mem_cgroup_thresholds {
215 /* Primary thresholds array */
216 struct mem_cgroup_threshold_ary *primary;
217 /*
218 * Spare threshold array.
219 * This is needed to make mem_cgroup_unregister_event() "never fail".
220 * It must be able to store at least primary->size - 1 entries.
221 */
222 struct mem_cgroup_threshold_ary *spare;
223};
224
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225/* for OOM */
226struct mem_cgroup_eventfd_list {
227 struct list_head list;
228 struct eventfd_ctx *eventfd;
229};
2e72b634 230
79bd9814
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231/*
232 * cgroup_event represents events which userspace want to receive.
233 */
3bc942f3 234struct mem_cgroup_event {
79bd9814 235 /*
59b6f873 236 * memcg which the event belongs to.
79bd9814 237 */
59b6f873 238 struct mem_cgroup *memcg;
79bd9814
TH
239 /*
240 * eventfd to signal userspace about the event.
241 */
242 struct eventfd_ctx *eventfd;
243 /*
244 * Each of these stored in a list by the cgroup.
245 */
246 struct list_head list;
fba94807
TH
247 /*
248 * register_event() callback will be used to add new userspace
249 * waiter for changes related to this event. Use eventfd_signal()
250 * on eventfd to send notification to userspace.
251 */
59b6f873 252 int (*register_event)(struct mem_cgroup *memcg,
347c4a87 253 struct eventfd_ctx *eventfd, const char *args);
fba94807
TH
254 /*
255 * unregister_event() callback will be called when userspace closes
256 * the eventfd or on cgroup removing. This callback must be set,
257 * if you want provide notification functionality.
258 */
59b6f873 259 void (*unregister_event)(struct mem_cgroup *memcg,
fba94807 260 struct eventfd_ctx *eventfd);
79bd9814
TH
261 /*
262 * All fields below needed to unregister event when
263 * userspace closes eventfd.
264 */
265 poll_table pt;
266 wait_queue_head_t *wqh;
267 wait_queue_t wait;
268 struct work_struct remove;
269};
270
c0ff4b85
R
271static void mem_cgroup_threshold(struct mem_cgroup *memcg);
272static void mem_cgroup_oom_notify(struct mem_cgroup *memcg);
2e72b634 273
8cdea7c0
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274/*
275 * The memory controller data structure. The memory controller controls both
276 * page cache and RSS per cgroup. We would eventually like to provide
277 * statistics based on the statistics developed by Rik Van Riel for clock-pro,
278 * to help the administrator determine what knobs to tune.
279 *
280 * TODO: Add a water mark for the memory controller. Reclaim will begin when
8a9f3ccd
BS
281 * we hit the water mark. May be even add a low water mark, such that
282 * no reclaim occurs from a cgroup at it's low water mark, this is
283 * a feature that will be implemented much later in the future.
8cdea7c0
BS
284 */
285struct mem_cgroup {
286 struct cgroup_subsys_state css;
287 /*
288 * the counter to account for memory usage
289 */
290 struct res_counter res;
59927fb9 291
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AV
292 /* vmpressure notifications */
293 struct vmpressure vmpressure;
294
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295 /*
296 * the counter to account for mem+swap usage.
297 */
298 struct res_counter memsw;
59927fb9 299
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300 /*
301 * the counter to account for kernel memory usage.
302 */
303 struct res_counter kmem;
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BS
304 /*
305 * Should the accounting and control be hierarchical, per subtree?
306 */
307 bool use_hierarchy;
510fc4e1 308 unsigned long kmem_account_flags; /* See KMEM_ACCOUNTED_*, below */
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MH
309
310 bool oom_lock;
311 atomic_t under_oom;
3812c8c8 312 atomic_t oom_wakeups;
79dfdacc 313
1f4c025b 314 int swappiness;
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KH
315 /* OOM-Killer disable */
316 int oom_kill_disable;
a7885eb8 317
22a668d7
KH
318 /* set when res.limit == memsw.limit */
319 bool memsw_is_minimum;
320
2e72b634
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321 /* protect arrays of thresholds */
322 struct mutex thresholds_lock;
323
324 /* thresholds for memory usage. RCU-protected */
2c488db2 325 struct mem_cgroup_thresholds thresholds;
907860ed 326
2e72b634 327 /* thresholds for mem+swap usage. RCU-protected */
2c488db2 328 struct mem_cgroup_thresholds memsw_thresholds;
907860ed 329
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KH
330 /* For oom notifier event fd */
331 struct list_head oom_notify;
185efc0f 332
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333 /*
334 * Should we move charges of a task when a task is moved into this
335 * mem_cgroup ? And what type of charges should we move ?
336 */
f894ffa8 337 unsigned long move_charge_at_immigrate;
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338 /*
339 * set > 0 if pages under this cgroup are moving to other cgroup.
340 */
341 atomic_t moving_account;
312734c0
KH
342 /* taken only while moving_account > 0 */
343 spinlock_t move_lock;
d52aa412 344 /*
c62b1a3b 345 * percpu counter.
d52aa412 346 */
3a7951b4 347 struct mem_cgroup_stat_cpu __percpu *stat;
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KH
348 /*
349 * used when a cpu is offlined or other synchronizations
350 * See mem_cgroup_read_stat().
351 */
352 struct mem_cgroup_stat_cpu nocpu_base;
353 spinlock_t pcp_counter_lock;
d1a4c0b3 354
5f578161 355 atomic_t dead_count;
4bd2c1ee 356#if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_INET)
2e685cad 357 struct cg_proto tcp_mem;
d1a4c0b3 358#endif
2633d7a0 359#if defined(CONFIG_MEMCG_KMEM)
bd673145
VD
360 /* analogous to slab_common's slab_caches list, but per-memcg;
361 * protected by memcg_slab_mutex */
2633d7a0 362 struct list_head memcg_slab_caches;
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GC
363 /* Index in the kmem_cache->memcg_params->memcg_caches array */
364 int kmemcg_id;
365#endif
45cf7ebd
GC
366
367 int last_scanned_node;
368#if MAX_NUMNODES > 1
369 nodemask_t scan_nodes;
370 atomic_t numainfo_events;
371 atomic_t numainfo_updating;
372#endif
70ddf637 373
fba94807
TH
374 /* List of events which userspace want to receive */
375 struct list_head event_list;
376 spinlock_t event_list_lock;
377
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JW
378 struct mem_cgroup_per_node *nodeinfo[0];
379 /* WARNING: nodeinfo must be the last member here */
8cdea7c0
BS
380};
381
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382/* internal only representation about the status of kmem accounting. */
383enum {
6de64beb 384 KMEM_ACCOUNTED_ACTIVE, /* accounted by this cgroup itself */
7de37682 385 KMEM_ACCOUNTED_DEAD, /* dead memcg with pending kmem charges */
510fc4e1
GC
386};
387
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GC
388#ifdef CONFIG_MEMCG_KMEM
389static inline void memcg_kmem_set_active(struct mem_cgroup *memcg)
390{
391 set_bit(KMEM_ACCOUNTED_ACTIVE, &memcg->kmem_account_flags);
392}
7de37682
GC
393
394static bool memcg_kmem_is_active(struct mem_cgroup *memcg)
395{
396 return test_bit(KMEM_ACCOUNTED_ACTIVE, &memcg->kmem_account_flags);
397}
398
399static void memcg_kmem_mark_dead(struct mem_cgroup *memcg)
400{
10d5ebf4
LZ
401 /*
402 * Our caller must use css_get() first, because memcg_uncharge_kmem()
403 * will call css_put() if it sees the memcg is dead.
404 */
405 smp_wmb();
7de37682
GC
406 if (test_bit(KMEM_ACCOUNTED_ACTIVE, &memcg->kmem_account_flags))
407 set_bit(KMEM_ACCOUNTED_DEAD, &memcg->kmem_account_flags);
408}
409
410static bool memcg_kmem_test_and_clear_dead(struct mem_cgroup *memcg)
411{
412 return test_and_clear_bit(KMEM_ACCOUNTED_DEAD,
413 &memcg->kmem_account_flags);
414}
510fc4e1
GC
415#endif
416
7dc74be0
DN
417/* Stuffs for move charges at task migration. */
418/*
ee5e8472
GC
419 * Types of charges to be moved. "move_charge_at_immitgrate" and
420 * "immigrate_flags" are treated as a left-shifted bitmap of these types.
7dc74be0
DN
421 */
422enum move_type {
4ffef5fe 423 MOVE_CHARGE_TYPE_ANON, /* private anonymous page and swap of it */
87946a72 424 MOVE_CHARGE_TYPE_FILE, /* file page(including tmpfs) and swap of it */
7dc74be0
DN
425 NR_MOVE_TYPE,
426};
427
4ffef5fe
DN
428/* "mc" and its members are protected by cgroup_mutex */
429static struct move_charge_struct {
b1dd693e 430 spinlock_t lock; /* for from, to */
4ffef5fe
DN
431 struct mem_cgroup *from;
432 struct mem_cgroup *to;
ee5e8472 433 unsigned long immigrate_flags;
4ffef5fe 434 unsigned long precharge;
854ffa8d 435 unsigned long moved_charge;
483c30b5 436 unsigned long moved_swap;
8033b97c
DN
437 struct task_struct *moving_task; /* a task moving charges */
438 wait_queue_head_t waitq; /* a waitq for other context */
439} mc = {
2bd9bb20 440 .lock = __SPIN_LOCK_UNLOCKED(mc.lock),
8033b97c
DN
441 .waitq = __WAIT_QUEUE_HEAD_INITIALIZER(mc.waitq),
442};
4ffef5fe 443
90254a65
DN
444static bool move_anon(void)
445{
ee5e8472 446 return test_bit(MOVE_CHARGE_TYPE_ANON, &mc.immigrate_flags);
90254a65
DN
447}
448
87946a72
DN
449static bool move_file(void)
450{
ee5e8472 451 return test_bit(MOVE_CHARGE_TYPE_FILE, &mc.immigrate_flags);
87946a72
DN
452}
453
4e416953
BS
454/*
455 * Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft
456 * limit reclaim to prevent infinite loops, if they ever occur.
457 */
a0db00fc 458#define MEM_CGROUP_MAX_RECLAIM_LOOPS 100
bb4cc1a8 459#define MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS 2
4e416953 460
217bc319
KH
461enum charge_type {
462 MEM_CGROUP_CHARGE_TYPE_CACHE = 0,
41326c17 463 MEM_CGROUP_CHARGE_TYPE_ANON,
d13d1443 464 MEM_CGROUP_CHARGE_TYPE_SWAPOUT, /* for accounting swapcache */
8a9478ca 465 MEM_CGROUP_CHARGE_TYPE_DROP, /* a page was unused swap cache */
c05555b5
KH
466 NR_CHARGE_TYPE,
467};
468
8c7c6e34 469/* for encoding cft->private value on file */
86ae53e1
GC
470enum res_type {
471 _MEM,
472 _MEMSWAP,
473 _OOM_TYPE,
510fc4e1 474 _KMEM,
86ae53e1
GC
475};
476
a0db00fc
KS
477#define MEMFILE_PRIVATE(x, val) ((x) << 16 | (val))
478#define MEMFILE_TYPE(val) ((val) >> 16 & 0xffff)
8c7c6e34 479#define MEMFILE_ATTR(val) ((val) & 0xffff)
9490ff27
KH
480/* Used for OOM nofiier */
481#define OOM_CONTROL (0)
8c7c6e34 482
75822b44
BS
483/*
484 * Reclaim flags for mem_cgroup_hierarchical_reclaim
485 */
486#define MEM_CGROUP_RECLAIM_NOSWAP_BIT 0x0
487#define MEM_CGROUP_RECLAIM_NOSWAP (1 << MEM_CGROUP_RECLAIM_NOSWAP_BIT)
488#define MEM_CGROUP_RECLAIM_SHRINK_BIT 0x1
489#define MEM_CGROUP_RECLAIM_SHRINK (1 << MEM_CGROUP_RECLAIM_SHRINK_BIT)
490
0999821b
GC
491/*
492 * The memcg_create_mutex will be held whenever a new cgroup is created.
493 * As a consequence, any change that needs to protect against new child cgroups
494 * appearing has to hold it as well.
495 */
496static DEFINE_MUTEX(memcg_create_mutex);
497
b2145145
WL
498struct mem_cgroup *mem_cgroup_from_css(struct cgroup_subsys_state *s)
499{
a7c6d554 500 return s ? container_of(s, struct mem_cgroup, css) : NULL;
b2145145
WL
501}
502
70ddf637
AV
503/* Some nice accessors for the vmpressure. */
504struct vmpressure *memcg_to_vmpressure(struct mem_cgroup *memcg)
505{
506 if (!memcg)
507 memcg = root_mem_cgroup;
508 return &memcg->vmpressure;
509}
510
511struct cgroup_subsys_state *vmpressure_to_css(struct vmpressure *vmpr)
512{
513 return &container_of(vmpr, struct mem_cgroup, vmpressure)->css;
514}
515
7ffc0edc
MH
516static inline bool mem_cgroup_is_root(struct mem_cgroup *memcg)
517{
518 return (memcg == root_mem_cgroup);
519}
520
4219b2da
LZ
521/*
522 * We restrict the id in the range of [1, 65535], so it can fit into
523 * an unsigned short.
524 */
525#define MEM_CGROUP_ID_MAX USHRT_MAX
526
34c00c31
LZ
527static inline unsigned short mem_cgroup_id(struct mem_cgroup *memcg)
528{
15a4c835 529 return memcg->css.id;
34c00c31
LZ
530}
531
532static inline struct mem_cgroup *mem_cgroup_from_id(unsigned short id)
533{
534 struct cgroup_subsys_state *css;
535
7d699ddb 536 css = css_from_id(id, &memory_cgrp_subsys);
34c00c31
LZ
537 return mem_cgroup_from_css(css);
538}
539
e1aab161 540/* Writing them here to avoid exposing memcg's inner layout */
4bd2c1ee 541#if defined(CONFIG_INET) && defined(CONFIG_MEMCG_KMEM)
e1aab161 542
e1aab161
GC
543void sock_update_memcg(struct sock *sk)
544{
376be5ff 545 if (mem_cgroup_sockets_enabled) {
e1aab161 546 struct mem_cgroup *memcg;
3f134619 547 struct cg_proto *cg_proto;
e1aab161
GC
548
549 BUG_ON(!sk->sk_prot->proto_cgroup);
550
f3f511e1
GC
551 /* Socket cloning can throw us here with sk_cgrp already
552 * filled. It won't however, necessarily happen from
553 * process context. So the test for root memcg given
554 * the current task's memcg won't help us in this case.
555 *
556 * Respecting the original socket's memcg is a better
557 * decision in this case.
558 */
559 if (sk->sk_cgrp) {
560 BUG_ON(mem_cgroup_is_root(sk->sk_cgrp->memcg));
5347e5ae 561 css_get(&sk->sk_cgrp->memcg->css);
f3f511e1
GC
562 return;
563 }
564
e1aab161
GC
565 rcu_read_lock();
566 memcg = mem_cgroup_from_task(current);
3f134619 567 cg_proto = sk->sk_prot->proto_cgroup(memcg);
5347e5ae 568 if (!mem_cgroup_is_root(memcg) &&
ec903c0c
TH
569 memcg_proto_active(cg_proto) &&
570 css_tryget_online(&memcg->css)) {
3f134619 571 sk->sk_cgrp = cg_proto;
e1aab161
GC
572 }
573 rcu_read_unlock();
574 }
575}
576EXPORT_SYMBOL(sock_update_memcg);
577
578void sock_release_memcg(struct sock *sk)
579{
376be5ff 580 if (mem_cgroup_sockets_enabled && sk->sk_cgrp) {
e1aab161
GC
581 struct mem_cgroup *memcg;
582 WARN_ON(!sk->sk_cgrp->memcg);
583 memcg = sk->sk_cgrp->memcg;
5347e5ae 584 css_put(&sk->sk_cgrp->memcg->css);
e1aab161
GC
585 }
586}
d1a4c0b3
GC
587
588struct cg_proto *tcp_proto_cgroup(struct mem_cgroup *memcg)
589{
590 if (!memcg || mem_cgroup_is_root(memcg))
591 return NULL;
592
2e685cad 593 return &memcg->tcp_mem;
d1a4c0b3
GC
594}
595EXPORT_SYMBOL(tcp_proto_cgroup);
e1aab161 596
3f134619
GC
597static void disarm_sock_keys(struct mem_cgroup *memcg)
598{
2e685cad 599 if (!memcg_proto_activated(&memcg->tcp_mem))
3f134619
GC
600 return;
601 static_key_slow_dec(&memcg_socket_limit_enabled);
602}
603#else
604static void disarm_sock_keys(struct mem_cgroup *memcg)
605{
606}
607#endif
608
a8964b9b 609#ifdef CONFIG_MEMCG_KMEM
55007d84
GC
610/*
611 * This will be the memcg's index in each cache's ->memcg_params->memcg_caches.
b8627835
LZ
612 * The main reason for not using cgroup id for this:
613 * this works better in sparse environments, where we have a lot of memcgs,
614 * but only a few kmem-limited. Or also, if we have, for instance, 200
615 * memcgs, and none but the 200th is kmem-limited, we'd have to have a
616 * 200 entry array for that.
55007d84
GC
617 *
618 * The current size of the caches array is stored in
619 * memcg_limited_groups_array_size. It will double each time we have to
620 * increase it.
621 */
622static DEFINE_IDA(kmem_limited_groups);
749c5415
GC
623int memcg_limited_groups_array_size;
624
55007d84
GC
625/*
626 * MIN_SIZE is different than 1, because we would like to avoid going through
627 * the alloc/free process all the time. In a small machine, 4 kmem-limited
628 * cgroups is a reasonable guess. In the future, it could be a parameter or
629 * tunable, but that is strictly not necessary.
630 *
b8627835 631 * MAX_SIZE should be as large as the number of cgrp_ids. Ideally, we could get
55007d84
GC
632 * this constant directly from cgroup, but it is understandable that this is
633 * better kept as an internal representation in cgroup.c. In any case, the
b8627835 634 * cgrp_id space is not getting any smaller, and we don't have to necessarily
55007d84
GC
635 * increase ours as well if it increases.
636 */
637#define MEMCG_CACHES_MIN_SIZE 4
b8627835 638#define MEMCG_CACHES_MAX_SIZE MEM_CGROUP_ID_MAX
55007d84 639
d7f25f8a
GC
640/*
641 * A lot of the calls to the cache allocation functions are expected to be
642 * inlined by the compiler. Since the calls to memcg_kmem_get_cache are
643 * conditional to this static branch, we'll have to allow modules that does
644 * kmem_cache_alloc and the such to see this symbol as well
645 */
a8964b9b 646struct static_key memcg_kmem_enabled_key;
d7f25f8a 647EXPORT_SYMBOL(memcg_kmem_enabled_key);
a8964b9b
GC
648
649static void disarm_kmem_keys(struct mem_cgroup *memcg)
650{
55007d84 651 if (memcg_kmem_is_active(memcg)) {
a8964b9b 652 static_key_slow_dec(&memcg_kmem_enabled_key);
55007d84
GC
653 ida_simple_remove(&kmem_limited_groups, memcg->kmemcg_id);
654 }
bea207c8
GC
655 /*
656 * This check can't live in kmem destruction function,
657 * since the charges will outlive the cgroup
658 */
659 WARN_ON(res_counter_read_u64(&memcg->kmem, RES_USAGE) != 0);
a8964b9b
GC
660}
661#else
662static void disarm_kmem_keys(struct mem_cgroup *memcg)
663{
664}
665#endif /* CONFIG_MEMCG_KMEM */
666
667static void disarm_static_keys(struct mem_cgroup *memcg)
668{
669 disarm_sock_keys(memcg);
670 disarm_kmem_keys(memcg);
671}
672
c0ff4b85 673static void drain_all_stock_async(struct mem_cgroup *memcg);
8c7c6e34 674
f64c3f54 675static struct mem_cgroup_per_zone *
e231875b 676mem_cgroup_zone_zoneinfo(struct mem_cgroup *memcg, struct zone *zone)
f64c3f54 677{
e231875b
JZ
678 int nid = zone_to_nid(zone);
679 int zid = zone_idx(zone);
680
54f72fe0 681 return &memcg->nodeinfo[nid]->zoneinfo[zid];
f64c3f54
BS
682}
683
c0ff4b85 684struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *memcg)
d324236b 685{
c0ff4b85 686 return &memcg->css;
d324236b
WF
687}
688
f64c3f54 689static struct mem_cgroup_per_zone *
e231875b 690mem_cgroup_page_zoneinfo(struct mem_cgroup *memcg, struct page *page)
f64c3f54 691{
97a6c37b
JW
692 int nid = page_to_nid(page);
693 int zid = page_zonenum(page);
f64c3f54 694
e231875b 695 return &memcg->nodeinfo[nid]->zoneinfo[zid];
f64c3f54
BS
696}
697
bb4cc1a8
AM
698static struct mem_cgroup_tree_per_zone *
699soft_limit_tree_node_zone(int nid, int zid)
700{
701 return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid];
702}
703
704static struct mem_cgroup_tree_per_zone *
705soft_limit_tree_from_page(struct page *page)
706{
707 int nid = page_to_nid(page);
708 int zid = page_zonenum(page);
709
710 return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid];
711}
712
cf2c8127
JW
713static void __mem_cgroup_insert_exceeded(struct mem_cgroup_per_zone *mz,
714 struct mem_cgroup_tree_per_zone *mctz,
715 unsigned long long new_usage_in_excess)
bb4cc1a8
AM
716{
717 struct rb_node **p = &mctz->rb_root.rb_node;
718 struct rb_node *parent = NULL;
719 struct mem_cgroup_per_zone *mz_node;
720
721 if (mz->on_tree)
722 return;
723
724 mz->usage_in_excess = new_usage_in_excess;
725 if (!mz->usage_in_excess)
726 return;
727 while (*p) {
728 parent = *p;
729 mz_node = rb_entry(parent, struct mem_cgroup_per_zone,
730 tree_node);
731 if (mz->usage_in_excess < mz_node->usage_in_excess)
732 p = &(*p)->rb_left;
733 /*
734 * We can't avoid mem cgroups that are over their soft
735 * limit by the same amount
736 */
737 else if (mz->usage_in_excess >= mz_node->usage_in_excess)
738 p = &(*p)->rb_right;
739 }
740 rb_link_node(&mz->tree_node, parent, p);
741 rb_insert_color(&mz->tree_node, &mctz->rb_root);
742 mz->on_tree = true;
743}
744
cf2c8127
JW
745static void __mem_cgroup_remove_exceeded(struct mem_cgroup_per_zone *mz,
746 struct mem_cgroup_tree_per_zone *mctz)
bb4cc1a8
AM
747{
748 if (!mz->on_tree)
749 return;
750 rb_erase(&mz->tree_node, &mctz->rb_root);
751 mz->on_tree = false;
752}
753
cf2c8127
JW
754static void mem_cgroup_remove_exceeded(struct mem_cgroup_per_zone *mz,
755 struct mem_cgroup_tree_per_zone *mctz)
bb4cc1a8
AM
756{
757 spin_lock(&mctz->lock);
cf2c8127 758 __mem_cgroup_remove_exceeded(mz, mctz);
bb4cc1a8
AM
759 spin_unlock(&mctz->lock);
760}
761
762
763static void mem_cgroup_update_tree(struct mem_cgroup *memcg, struct page *page)
764{
765 unsigned long long excess;
766 struct mem_cgroup_per_zone *mz;
767 struct mem_cgroup_tree_per_zone *mctz;
bb4cc1a8 768
e231875b 769 mctz = soft_limit_tree_from_page(page);
bb4cc1a8
AM
770 /*
771 * Necessary to update all ancestors when hierarchy is used.
772 * because their event counter is not touched.
773 */
774 for (; memcg; memcg = parent_mem_cgroup(memcg)) {
e231875b 775 mz = mem_cgroup_page_zoneinfo(memcg, page);
bb4cc1a8
AM
776 excess = res_counter_soft_limit_excess(&memcg->res);
777 /*
778 * We have to update the tree if mz is on RB-tree or
779 * mem is over its softlimit.
780 */
781 if (excess || mz->on_tree) {
782 spin_lock(&mctz->lock);
783 /* if on-tree, remove it */
784 if (mz->on_tree)
cf2c8127 785 __mem_cgroup_remove_exceeded(mz, mctz);
bb4cc1a8
AM
786 /*
787 * Insert again. mz->usage_in_excess will be updated.
788 * If excess is 0, no tree ops.
789 */
cf2c8127 790 __mem_cgroup_insert_exceeded(mz, mctz, excess);
bb4cc1a8
AM
791 spin_unlock(&mctz->lock);
792 }
793 }
794}
795
796static void mem_cgroup_remove_from_trees(struct mem_cgroup *memcg)
797{
bb4cc1a8 798 struct mem_cgroup_tree_per_zone *mctz;
e231875b
JZ
799 struct mem_cgroup_per_zone *mz;
800 int nid, zid;
bb4cc1a8 801
e231875b
JZ
802 for_each_node(nid) {
803 for (zid = 0; zid < MAX_NR_ZONES; zid++) {
804 mz = &memcg->nodeinfo[nid]->zoneinfo[zid];
805 mctz = soft_limit_tree_node_zone(nid, zid);
cf2c8127 806 mem_cgroup_remove_exceeded(mz, mctz);
bb4cc1a8
AM
807 }
808 }
809}
810
811static struct mem_cgroup_per_zone *
812__mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
813{
814 struct rb_node *rightmost = NULL;
815 struct mem_cgroup_per_zone *mz;
816
817retry:
818 mz = NULL;
819 rightmost = rb_last(&mctz->rb_root);
820 if (!rightmost)
821 goto done; /* Nothing to reclaim from */
822
823 mz = rb_entry(rightmost, struct mem_cgroup_per_zone, tree_node);
824 /*
825 * Remove the node now but someone else can add it back,
826 * we will to add it back at the end of reclaim to its correct
827 * position in the tree.
828 */
cf2c8127 829 __mem_cgroup_remove_exceeded(mz, mctz);
bb4cc1a8 830 if (!res_counter_soft_limit_excess(&mz->memcg->res) ||
ec903c0c 831 !css_tryget_online(&mz->memcg->css))
bb4cc1a8
AM
832 goto retry;
833done:
834 return mz;
835}
836
837static struct mem_cgroup_per_zone *
838mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
839{
840 struct mem_cgroup_per_zone *mz;
841
842 spin_lock(&mctz->lock);
843 mz = __mem_cgroup_largest_soft_limit_node(mctz);
844 spin_unlock(&mctz->lock);
845 return mz;
846}
847
711d3d2c
KH
848/*
849 * Implementation Note: reading percpu statistics for memcg.
850 *
851 * Both of vmstat[] and percpu_counter has threshold and do periodic
852 * synchronization to implement "quick" read. There are trade-off between
853 * reading cost and precision of value. Then, we may have a chance to implement
854 * a periodic synchronizion of counter in memcg's counter.
855 *
856 * But this _read() function is used for user interface now. The user accounts
857 * memory usage by memory cgroup and he _always_ requires exact value because
858 * he accounts memory. Even if we provide quick-and-fuzzy read, we always
859 * have to visit all online cpus and make sum. So, for now, unnecessary
860 * synchronization is not implemented. (just implemented for cpu hotplug)
861 *
862 * If there are kernel internal actions which can make use of some not-exact
863 * value, and reading all cpu value can be performance bottleneck in some
864 * common workload, threashold and synchonization as vmstat[] should be
865 * implemented.
866 */
c0ff4b85 867static long mem_cgroup_read_stat(struct mem_cgroup *memcg,
7a159cc9 868 enum mem_cgroup_stat_index idx)
c62b1a3b 869{
7a159cc9 870 long val = 0;
c62b1a3b 871 int cpu;
c62b1a3b 872
711d3d2c
KH
873 get_online_cpus();
874 for_each_online_cpu(cpu)
c0ff4b85 875 val += per_cpu(memcg->stat->count[idx], cpu);
711d3d2c 876#ifdef CONFIG_HOTPLUG_CPU
c0ff4b85
R
877 spin_lock(&memcg->pcp_counter_lock);
878 val += memcg->nocpu_base.count[idx];
879 spin_unlock(&memcg->pcp_counter_lock);
711d3d2c
KH
880#endif
881 put_online_cpus();
c62b1a3b
KH
882 return val;
883}
884
c0ff4b85 885static void mem_cgroup_swap_statistics(struct mem_cgroup *memcg,
0c3e73e8
BS
886 bool charge)
887{
888 int val = (charge) ? 1 : -1;
bff6bb83 889 this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_SWAP], val);
0c3e73e8
BS
890}
891
c0ff4b85 892static unsigned long mem_cgroup_read_events(struct mem_cgroup *memcg,
e9f8974f
JW
893 enum mem_cgroup_events_index idx)
894{
895 unsigned long val = 0;
896 int cpu;
897
9c567512 898 get_online_cpus();
e9f8974f 899 for_each_online_cpu(cpu)
c0ff4b85 900 val += per_cpu(memcg->stat->events[idx], cpu);
e9f8974f 901#ifdef CONFIG_HOTPLUG_CPU
c0ff4b85
R
902 spin_lock(&memcg->pcp_counter_lock);
903 val += memcg->nocpu_base.events[idx];
904 spin_unlock(&memcg->pcp_counter_lock);
e9f8974f 905#endif
9c567512 906 put_online_cpus();
e9f8974f
JW
907 return val;
908}
909
c0ff4b85 910static void mem_cgroup_charge_statistics(struct mem_cgroup *memcg,
b070e65c 911 struct page *page,
b2402857 912 bool anon, int nr_pages)
d52aa412 913{
b2402857
KH
914 /*
915 * Here, RSS means 'mapped anon' and anon's SwapCache. Shmem/tmpfs is
916 * counted as CACHE even if it's on ANON LRU.
917 */
918 if (anon)
919 __this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_RSS],
c0ff4b85 920 nr_pages);
d52aa412 921 else
b2402857 922 __this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_CACHE],
c0ff4b85 923 nr_pages);
55e462b0 924
b070e65c
DR
925 if (PageTransHuge(page))
926 __this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_RSS_HUGE],
927 nr_pages);
928
e401f176
KH
929 /* pagein of a big page is an event. So, ignore page size */
930 if (nr_pages > 0)
c0ff4b85 931 __this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGPGIN]);
3751d604 932 else {
c0ff4b85 933 __this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGPGOUT]);
3751d604
KH
934 nr_pages = -nr_pages; /* for event */
935 }
e401f176 936
13114716 937 __this_cpu_add(memcg->stat->nr_page_events, nr_pages);
6d12e2d8
KH
938}
939
e231875b 940unsigned long mem_cgroup_get_lru_size(struct lruvec *lruvec, enum lru_list lru)
074291fe
KK
941{
942 struct mem_cgroup_per_zone *mz;
943
944 mz = container_of(lruvec, struct mem_cgroup_per_zone, lruvec);
945 return mz->lru_size[lru];
946}
947
e231875b
JZ
948static unsigned long mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg,
949 int nid,
950 unsigned int lru_mask)
bb2a0de9 951{
e231875b 952 unsigned long nr = 0;
889976db
YH
953 int zid;
954
e231875b 955 VM_BUG_ON((unsigned)nid >= nr_node_ids);
bb2a0de9 956
e231875b
JZ
957 for (zid = 0; zid < MAX_NR_ZONES; zid++) {
958 struct mem_cgroup_per_zone *mz;
959 enum lru_list lru;
960
961 for_each_lru(lru) {
962 if (!(BIT(lru) & lru_mask))
963 continue;
964 mz = &memcg->nodeinfo[nid]->zoneinfo[zid];
965 nr += mz->lru_size[lru];
966 }
967 }
968 return nr;
889976db 969}
bb2a0de9 970
c0ff4b85 971static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup *memcg,
bb2a0de9 972 unsigned int lru_mask)
6d12e2d8 973{
e231875b 974 unsigned long nr = 0;
889976db 975 int nid;
6d12e2d8 976
31aaea4a 977 for_each_node_state(nid, N_MEMORY)
e231875b
JZ
978 nr += mem_cgroup_node_nr_lru_pages(memcg, nid, lru_mask);
979 return nr;
d52aa412
KH
980}
981
f53d7ce3
JW
982static bool mem_cgroup_event_ratelimit(struct mem_cgroup *memcg,
983 enum mem_cgroup_events_target target)
7a159cc9
JW
984{
985 unsigned long val, next;
986
13114716 987 val = __this_cpu_read(memcg->stat->nr_page_events);
4799401f 988 next = __this_cpu_read(memcg->stat->targets[target]);
7a159cc9 989 /* from time_after() in jiffies.h */
f53d7ce3
JW
990 if ((long)next - (long)val < 0) {
991 switch (target) {
992 case MEM_CGROUP_TARGET_THRESH:
993 next = val + THRESHOLDS_EVENTS_TARGET;
994 break;
bb4cc1a8
AM
995 case MEM_CGROUP_TARGET_SOFTLIMIT:
996 next = val + SOFTLIMIT_EVENTS_TARGET;
997 break;
f53d7ce3
JW
998 case MEM_CGROUP_TARGET_NUMAINFO:
999 next = val + NUMAINFO_EVENTS_TARGET;
1000 break;
1001 default:
1002 break;
1003 }
1004 __this_cpu_write(memcg->stat->targets[target], next);
1005 return true;
7a159cc9 1006 }
f53d7ce3 1007 return false;
d2265e6f
KH
1008}
1009
1010/*
1011 * Check events in order.
1012 *
1013 */
c0ff4b85 1014static void memcg_check_events(struct mem_cgroup *memcg, struct page *page)
d2265e6f 1015{
4799401f 1016 preempt_disable();
d2265e6f 1017 /* threshold event is triggered in finer grain than soft limit */
f53d7ce3
JW
1018 if (unlikely(mem_cgroup_event_ratelimit(memcg,
1019 MEM_CGROUP_TARGET_THRESH))) {
bb4cc1a8 1020 bool do_softlimit;
82b3f2a7 1021 bool do_numainfo __maybe_unused;
f53d7ce3 1022
bb4cc1a8
AM
1023 do_softlimit = mem_cgroup_event_ratelimit(memcg,
1024 MEM_CGROUP_TARGET_SOFTLIMIT);
f53d7ce3
JW
1025#if MAX_NUMNODES > 1
1026 do_numainfo = mem_cgroup_event_ratelimit(memcg,
1027 MEM_CGROUP_TARGET_NUMAINFO);
1028#endif
1029 preempt_enable();
1030
c0ff4b85 1031 mem_cgroup_threshold(memcg);
bb4cc1a8
AM
1032 if (unlikely(do_softlimit))
1033 mem_cgroup_update_tree(memcg, page);
453a9bf3 1034#if MAX_NUMNODES > 1
f53d7ce3 1035 if (unlikely(do_numainfo))
c0ff4b85 1036 atomic_inc(&memcg->numainfo_events);
453a9bf3 1037#endif
f53d7ce3
JW
1038 } else
1039 preempt_enable();
d2265e6f
KH
1040}
1041
cf475ad2 1042struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
78fb7466 1043{
31a78f23
BS
1044 /*
1045 * mm_update_next_owner() may clear mm->owner to NULL
1046 * if it races with swapoff, page migration, etc.
1047 * So this can be called with p == NULL.
1048 */
1049 if (unlikely(!p))
1050 return NULL;
1051
073219e9 1052 return mem_cgroup_from_css(task_css(p, memory_cgrp_id));
78fb7466
PE
1053}
1054
df381975 1055static struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm)
54595fe2 1056{
c0ff4b85 1057 struct mem_cgroup *memcg = NULL;
0b7f569e 1058
54595fe2
KH
1059 rcu_read_lock();
1060 do {
6f6acb00
MH
1061 /*
1062 * Page cache insertions can happen withou an
1063 * actual mm context, e.g. during disk probing
1064 * on boot, loopback IO, acct() writes etc.
1065 */
1066 if (unlikely(!mm))
df381975 1067 memcg = root_mem_cgroup;
6f6acb00
MH
1068 else {
1069 memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
1070 if (unlikely(!memcg))
1071 memcg = root_mem_cgroup;
1072 }
ec903c0c 1073 } while (!css_tryget_online(&memcg->css));
54595fe2 1074 rcu_read_unlock();
c0ff4b85 1075 return memcg;
54595fe2
KH
1076}
1077
16248d8f
MH
1078/*
1079 * Returns a next (in a pre-order walk) alive memcg (with elevated css
1080 * ref. count) or NULL if the whole root's subtree has been visited.
1081 *
1082 * helper function to be used by mem_cgroup_iter
1083 */
1084static struct mem_cgroup *__mem_cgroup_iter_next(struct mem_cgroup *root,
694fbc0f 1085 struct mem_cgroup *last_visited)
16248d8f 1086{
492eb21b 1087 struct cgroup_subsys_state *prev_css, *next_css;
16248d8f 1088
bd8815a6 1089 prev_css = last_visited ? &last_visited->css : NULL;
16248d8f 1090skip_node:
492eb21b 1091 next_css = css_next_descendant_pre(prev_css, &root->css);
16248d8f
MH
1092
1093 /*
1094 * Even if we found a group we have to make sure it is
1095 * alive. css && !memcg means that the groups should be
1096 * skipped and we should continue the tree walk.
1097 * last_visited css is safe to use because it is
1098 * protected by css_get and the tree walk is rcu safe.
0eef6156
MH
1099 *
1100 * We do not take a reference on the root of the tree walk
1101 * because we might race with the root removal when it would
1102 * be the only node in the iterated hierarchy and mem_cgroup_iter
1103 * would end up in an endless loop because it expects that at
1104 * least one valid node will be returned. Root cannot disappear
1105 * because caller of the iterator should hold it already so
1106 * skipping css reference should be safe.
16248d8f 1107 */
492eb21b 1108 if (next_css) {
ce48225f 1109 if ((next_css == &root->css) ||
ec903c0c
TH
1110 ((next_css->flags & CSS_ONLINE) &&
1111 css_tryget_online(next_css)))
d8ad3055 1112 return mem_cgroup_from_css(next_css);
0eef6156
MH
1113
1114 prev_css = next_css;
1115 goto skip_node;
16248d8f
MH
1116 }
1117
1118 return NULL;
1119}
1120
519ebea3
JW
1121static void mem_cgroup_iter_invalidate(struct mem_cgroup *root)
1122{
1123 /*
1124 * When a group in the hierarchy below root is destroyed, the
1125 * hierarchy iterator can no longer be trusted since it might
1126 * have pointed to the destroyed group. Invalidate it.
1127 */
1128 atomic_inc(&root->dead_count);
1129}
1130
1131static struct mem_cgroup *
1132mem_cgroup_iter_load(struct mem_cgroup_reclaim_iter *iter,
1133 struct mem_cgroup *root,
1134 int *sequence)
1135{
1136 struct mem_cgroup *position = NULL;
1137 /*
1138 * A cgroup destruction happens in two stages: offlining and
1139 * release. They are separated by a RCU grace period.
1140 *
1141 * If the iterator is valid, we may still race with an
1142 * offlining. The RCU lock ensures the object won't be
1143 * released, tryget will fail if we lost the race.
1144 */
1145 *sequence = atomic_read(&root->dead_count);
1146 if (iter->last_dead_count == *sequence) {
1147 smp_rmb();
1148 position = iter->last_visited;
ecc736fc
MH
1149
1150 /*
1151 * We cannot take a reference to root because we might race
1152 * with root removal and returning NULL would end up in
1153 * an endless loop on the iterator user level when root
1154 * would be returned all the time.
1155 */
1156 if (position && position != root &&
ec903c0c 1157 !css_tryget_online(&position->css))
519ebea3
JW
1158 position = NULL;
1159 }
1160 return position;
1161}
1162
1163static void mem_cgroup_iter_update(struct mem_cgroup_reclaim_iter *iter,
1164 struct mem_cgroup *last_visited,
1165 struct mem_cgroup *new_position,
ecc736fc 1166 struct mem_cgroup *root,
519ebea3
JW
1167 int sequence)
1168{
ecc736fc
MH
1169 /* root reference counting symmetric to mem_cgroup_iter_load */
1170 if (last_visited && last_visited != root)
519ebea3
JW
1171 css_put(&last_visited->css);
1172 /*
1173 * We store the sequence count from the time @last_visited was
1174 * loaded successfully instead of rereading it here so that we
1175 * don't lose destruction events in between. We could have
1176 * raced with the destruction of @new_position after all.
1177 */
1178 iter->last_visited = new_position;
1179 smp_wmb();
1180 iter->last_dead_count = sequence;
1181}
1182
5660048c
JW
1183/**
1184 * mem_cgroup_iter - iterate over memory cgroup hierarchy
1185 * @root: hierarchy root
1186 * @prev: previously returned memcg, NULL on first invocation
1187 * @reclaim: cookie for shared reclaim walks, NULL for full walks
1188 *
1189 * Returns references to children of the hierarchy below @root, or
1190 * @root itself, or %NULL after a full round-trip.
1191 *
1192 * Caller must pass the return value in @prev on subsequent
1193 * invocations for reference counting, or use mem_cgroup_iter_break()
1194 * to cancel a hierarchy walk before the round-trip is complete.
1195 *
1196 * Reclaimers can specify a zone and a priority level in @reclaim to
1197 * divide up the memcgs in the hierarchy among all concurrent
1198 * reclaimers operating on the same zone and priority.
1199 */
694fbc0f 1200struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root,
5660048c 1201 struct mem_cgroup *prev,
694fbc0f 1202 struct mem_cgroup_reclaim_cookie *reclaim)
14067bb3 1203{
9f3a0d09 1204 struct mem_cgroup *memcg = NULL;
542f85f9 1205 struct mem_cgroup *last_visited = NULL;
711d3d2c 1206
694fbc0f
AM
1207 if (mem_cgroup_disabled())
1208 return NULL;
5660048c 1209
9f3a0d09
JW
1210 if (!root)
1211 root = root_mem_cgroup;
7d74b06f 1212
9f3a0d09 1213 if (prev && !reclaim)
542f85f9 1214 last_visited = prev;
14067bb3 1215
9f3a0d09
JW
1216 if (!root->use_hierarchy && root != root_mem_cgroup) {
1217 if (prev)
c40046f3 1218 goto out_css_put;
694fbc0f 1219 return root;
9f3a0d09 1220 }
14067bb3 1221
542f85f9 1222 rcu_read_lock();
9f3a0d09 1223 while (!memcg) {
527a5ec9 1224 struct mem_cgroup_reclaim_iter *uninitialized_var(iter);
519ebea3 1225 int uninitialized_var(seq);
711d3d2c 1226
527a5ec9 1227 if (reclaim) {
527a5ec9
JW
1228 struct mem_cgroup_per_zone *mz;
1229
e231875b 1230 mz = mem_cgroup_zone_zoneinfo(root, reclaim->zone);
527a5ec9 1231 iter = &mz->reclaim_iter[reclaim->priority];
542f85f9 1232 if (prev && reclaim->generation != iter->generation) {
5f578161 1233 iter->last_visited = NULL;
542f85f9
MH
1234 goto out_unlock;
1235 }
5f578161 1236
519ebea3 1237 last_visited = mem_cgroup_iter_load(iter, root, &seq);
527a5ec9 1238 }
7d74b06f 1239
694fbc0f 1240 memcg = __mem_cgroup_iter_next(root, last_visited);
14067bb3 1241
527a5ec9 1242 if (reclaim) {
ecc736fc
MH
1243 mem_cgroup_iter_update(iter, last_visited, memcg, root,
1244 seq);
542f85f9 1245
19f39402 1246 if (!memcg)
527a5ec9
JW
1247 iter->generation++;
1248 else if (!prev && memcg)
1249 reclaim->generation = iter->generation;
1250 }
9f3a0d09 1251
694fbc0f 1252 if (prev && !memcg)
542f85f9 1253 goto out_unlock;
9f3a0d09 1254 }
542f85f9
MH
1255out_unlock:
1256 rcu_read_unlock();
c40046f3
MH
1257out_css_put:
1258 if (prev && prev != root)
1259 css_put(&prev->css);
1260
9f3a0d09 1261 return memcg;
14067bb3 1262}
7d74b06f 1263
5660048c
JW
1264/**
1265 * mem_cgroup_iter_break - abort a hierarchy walk prematurely
1266 * @root: hierarchy root
1267 * @prev: last visited hierarchy member as returned by mem_cgroup_iter()
1268 */
1269void mem_cgroup_iter_break(struct mem_cgroup *root,
1270 struct mem_cgroup *prev)
9f3a0d09
JW
1271{
1272 if (!root)
1273 root = root_mem_cgroup;
1274 if (prev && prev != root)
1275 css_put(&prev->css);
1276}
7d74b06f 1277
9f3a0d09
JW
1278/*
1279 * Iteration constructs for visiting all cgroups (under a tree). If
1280 * loops are exited prematurely (break), mem_cgroup_iter_break() must
1281 * be used for reference counting.
1282 */
1283#define for_each_mem_cgroup_tree(iter, root) \
527a5ec9 1284 for (iter = mem_cgroup_iter(root, NULL, NULL); \
9f3a0d09 1285 iter != NULL; \
527a5ec9 1286 iter = mem_cgroup_iter(root, iter, NULL))
711d3d2c 1287
9f3a0d09 1288#define for_each_mem_cgroup(iter) \
527a5ec9 1289 for (iter = mem_cgroup_iter(NULL, NULL, NULL); \
9f3a0d09 1290 iter != NULL; \
527a5ec9 1291 iter = mem_cgroup_iter(NULL, iter, NULL))
14067bb3 1292
68ae564b 1293void __mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx)
456f998e 1294{
c0ff4b85 1295 struct mem_cgroup *memcg;
456f998e 1296
456f998e 1297 rcu_read_lock();
c0ff4b85
R
1298 memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
1299 if (unlikely(!memcg))
456f998e
YH
1300 goto out;
1301
1302 switch (idx) {
456f998e 1303 case PGFAULT:
0e574a93
JW
1304 this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGFAULT]);
1305 break;
1306 case PGMAJFAULT:
1307 this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGMAJFAULT]);
456f998e
YH
1308 break;
1309 default:
1310 BUG();
1311 }
1312out:
1313 rcu_read_unlock();
1314}
68ae564b 1315EXPORT_SYMBOL(__mem_cgroup_count_vm_event);
456f998e 1316
925b7673
JW
1317/**
1318 * mem_cgroup_zone_lruvec - get the lru list vector for a zone and memcg
1319 * @zone: zone of the wanted lruvec
fa9add64 1320 * @memcg: memcg of the wanted lruvec
925b7673
JW
1321 *
1322 * Returns the lru list vector holding pages for the given @zone and
1323 * @mem. This can be the global zone lruvec, if the memory controller
1324 * is disabled.
1325 */
1326struct lruvec *mem_cgroup_zone_lruvec(struct zone *zone,
1327 struct mem_cgroup *memcg)
1328{
1329 struct mem_cgroup_per_zone *mz;
bea8c150 1330 struct lruvec *lruvec;
925b7673 1331
bea8c150
HD
1332 if (mem_cgroup_disabled()) {
1333 lruvec = &zone->lruvec;
1334 goto out;
1335 }
925b7673 1336
e231875b 1337 mz = mem_cgroup_zone_zoneinfo(memcg, zone);
bea8c150
HD
1338 lruvec = &mz->lruvec;
1339out:
1340 /*
1341 * Since a node can be onlined after the mem_cgroup was created,
1342 * we have to be prepared to initialize lruvec->zone here;
1343 * and if offlined then reonlined, we need to reinitialize it.
1344 */
1345 if (unlikely(lruvec->zone != zone))
1346 lruvec->zone = zone;
1347 return lruvec;
925b7673
JW
1348}
1349
08e552c6
KH
1350/*
1351 * Following LRU functions are allowed to be used without PCG_LOCK.
1352 * Operations are called by routine of global LRU independently from memcg.
1353 * What we have to take care of here is validness of pc->mem_cgroup.
1354 *
1355 * Changes to pc->mem_cgroup happens when
1356 * 1. charge
1357 * 2. moving account
1358 * In typical case, "charge" is done before add-to-lru. Exception is SwapCache.
1359 * It is added to LRU before charge.
1360 * If PCG_USED bit is not set, page_cgroup is not added to this private LRU.
1361 * When moving account, the page is not on LRU. It's isolated.
1362 */
4f98a2fe 1363
925b7673 1364/**
fa9add64 1365 * mem_cgroup_page_lruvec - return lruvec for adding an lru page
925b7673 1366 * @page: the page
fa9add64 1367 * @zone: zone of the page
925b7673 1368 */
fa9add64 1369struct lruvec *mem_cgroup_page_lruvec(struct page *page, struct zone *zone)
08e552c6 1370{
08e552c6 1371 struct mem_cgroup_per_zone *mz;
925b7673
JW
1372 struct mem_cgroup *memcg;
1373 struct page_cgroup *pc;
bea8c150 1374 struct lruvec *lruvec;
6d12e2d8 1375
bea8c150
HD
1376 if (mem_cgroup_disabled()) {
1377 lruvec = &zone->lruvec;
1378 goto out;
1379 }
925b7673 1380
08e552c6 1381 pc = lookup_page_cgroup(page);
38c5d72f 1382 memcg = pc->mem_cgroup;
7512102c
HD
1383
1384 /*
fa9add64 1385 * Surreptitiously switch any uncharged offlist page to root:
7512102c
HD
1386 * an uncharged page off lru does nothing to secure
1387 * its former mem_cgroup from sudden removal.
1388 *
1389 * Our caller holds lru_lock, and PageCgroupUsed is updated
1390 * under page_cgroup lock: between them, they make all uses
1391 * of pc->mem_cgroup safe.
1392 */
fa9add64 1393 if (!PageLRU(page) && !PageCgroupUsed(pc) && memcg != root_mem_cgroup)
7512102c
HD
1394 pc->mem_cgroup = memcg = root_mem_cgroup;
1395
e231875b 1396 mz = mem_cgroup_page_zoneinfo(memcg, page);
bea8c150
HD
1397 lruvec = &mz->lruvec;
1398out:
1399 /*
1400 * Since a node can be onlined after the mem_cgroup was created,
1401 * we have to be prepared to initialize lruvec->zone here;
1402 * and if offlined then reonlined, we need to reinitialize it.
1403 */
1404 if (unlikely(lruvec->zone != zone))
1405 lruvec->zone = zone;
1406 return lruvec;
08e552c6 1407}
b69408e8 1408
925b7673 1409/**
fa9add64
HD
1410 * mem_cgroup_update_lru_size - account for adding or removing an lru page
1411 * @lruvec: mem_cgroup per zone lru vector
1412 * @lru: index of lru list the page is sitting on
1413 * @nr_pages: positive when adding or negative when removing
925b7673 1414 *
fa9add64
HD
1415 * This function must be called when a page is added to or removed from an
1416 * lru list.
3f58a829 1417 */
fa9add64
HD
1418void mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru,
1419 int nr_pages)
3f58a829
MK
1420{
1421 struct mem_cgroup_per_zone *mz;
fa9add64 1422 unsigned long *lru_size;
3f58a829
MK
1423
1424 if (mem_cgroup_disabled())
1425 return;
1426
fa9add64
HD
1427 mz = container_of(lruvec, struct mem_cgroup_per_zone, lruvec);
1428 lru_size = mz->lru_size + lru;
1429 *lru_size += nr_pages;
1430 VM_BUG_ON((long)(*lru_size) < 0);
08e552c6 1431}
544122e5 1432
3e92041d 1433/*
c0ff4b85 1434 * Checks whether given mem is same or in the root_mem_cgroup's
3e92041d
MH
1435 * hierarchy subtree
1436 */
c3ac9a8a
JW
1437bool __mem_cgroup_same_or_subtree(const struct mem_cgroup *root_memcg,
1438 struct mem_cgroup *memcg)
3e92041d 1439{
91c63734
JW
1440 if (root_memcg == memcg)
1441 return true;
3a981f48 1442 if (!root_memcg->use_hierarchy || !memcg)
91c63734 1443 return false;
b47f77b5 1444 return cgroup_is_descendant(memcg->css.cgroup, root_memcg->css.cgroup);
c3ac9a8a
JW
1445}
1446
1447static bool mem_cgroup_same_or_subtree(const struct mem_cgroup *root_memcg,
1448 struct mem_cgroup *memcg)
1449{
1450 bool ret;
1451
91c63734 1452 rcu_read_lock();
c3ac9a8a 1453 ret = __mem_cgroup_same_or_subtree(root_memcg, memcg);
91c63734
JW
1454 rcu_read_unlock();
1455 return ret;
3e92041d
MH
1456}
1457
ffbdccf5
DR
1458bool task_in_mem_cgroup(struct task_struct *task,
1459 const struct mem_cgroup *memcg)
4c4a2214 1460{
0b7f569e 1461 struct mem_cgroup *curr = NULL;
158e0a2d 1462 struct task_struct *p;
ffbdccf5 1463 bool ret;
4c4a2214 1464
158e0a2d 1465 p = find_lock_task_mm(task);
de077d22 1466 if (p) {
df381975 1467 curr = get_mem_cgroup_from_mm(p->mm);
de077d22
DR
1468 task_unlock(p);
1469 } else {
1470 /*
1471 * All threads may have already detached their mm's, but the oom
1472 * killer still needs to detect if they have already been oom
1473 * killed to prevent needlessly killing additional tasks.
1474 */
ffbdccf5 1475 rcu_read_lock();
de077d22
DR
1476 curr = mem_cgroup_from_task(task);
1477 if (curr)
1478 css_get(&curr->css);
ffbdccf5 1479 rcu_read_unlock();
de077d22 1480 }
d31f56db 1481 /*
c0ff4b85 1482 * We should check use_hierarchy of "memcg" not "curr". Because checking
d31f56db 1483 * use_hierarchy of "curr" here make this function true if hierarchy is
c0ff4b85
R
1484 * enabled in "curr" and "curr" is a child of "memcg" in *cgroup*
1485 * hierarchy(even if use_hierarchy is disabled in "memcg").
d31f56db 1486 */
c0ff4b85 1487 ret = mem_cgroup_same_or_subtree(memcg, curr);
0b7f569e 1488 css_put(&curr->css);
4c4a2214
DR
1489 return ret;
1490}
1491
c56d5c7d 1492int mem_cgroup_inactive_anon_is_low(struct lruvec *lruvec)
14797e23 1493{
9b272977 1494 unsigned long inactive_ratio;
14797e23 1495 unsigned long inactive;
9b272977 1496 unsigned long active;
c772be93 1497 unsigned long gb;
14797e23 1498
4d7dcca2
HD
1499 inactive = mem_cgroup_get_lru_size(lruvec, LRU_INACTIVE_ANON);
1500 active = mem_cgroup_get_lru_size(lruvec, LRU_ACTIVE_ANON);
14797e23 1501
c772be93
KM
1502 gb = (inactive + active) >> (30 - PAGE_SHIFT);
1503 if (gb)
1504 inactive_ratio = int_sqrt(10 * gb);
1505 else
1506 inactive_ratio = 1;
1507
9b272977 1508 return inactive * inactive_ratio < active;
14797e23
KM
1509}
1510
6d61ef40
BS
1511#define mem_cgroup_from_res_counter(counter, member) \
1512 container_of(counter, struct mem_cgroup, member)
1513
19942822 1514/**
9d11ea9f 1515 * mem_cgroup_margin - calculate chargeable space of a memory cgroup
dad7557e 1516 * @memcg: the memory cgroup
19942822 1517 *
9d11ea9f 1518 * Returns the maximum amount of memory @mem can be charged with, in
7ec99d62 1519 * pages.
19942822 1520 */
c0ff4b85 1521static unsigned long mem_cgroup_margin(struct mem_cgroup *memcg)
19942822 1522{
9d11ea9f
JW
1523 unsigned long long margin;
1524
c0ff4b85 1525 margin = res_counter_margin(&memcg->res);
9d11ea9f 1526 if (do_swap_account)
c0ff4b85 1527 margin = min(margin, res_counter_margin(&memcg->memsw));
7ec99d62 1528 return margin >> PAGE_SHIFT;
19942822
JW
1529}
1530
1f4c025b 1531int mem_cgroup_swappiness(struct mem_cgroup *memcg)
a7885eb8 1532{
a7885eb8 1533 /* root ? */
14208b0e 1534 if (mem_cgroup_disabled() || !memcg->css.parent)
a7885eb8
KM
1535 return vm_swappiness;
1536
bf1ff263 1537 return memcg->swappiness;
a7885eb8
KM
1538}
1539
619d094b
KH
1540/*
1541 * memcg->moving_account is used for checking possibility that some thread is
1542 * calling move_account(). When a thread on CPU-A starts moving pages under
1543 * a memcg, other threads should check memcg->moving_account under
1544 * rcu_read_lock(), like this:
1545 *
1546 * CPU-A CPU-B
1547 * rcu_read_lock()
1548 * memcg->moving_account+1 if (memcg->mocing_account)
1549 * take heavy locks.
1550 * synchronize_rcu() update something.
1551 * rcu_read_unlock()
1552 * start move here.
1553 */
4331f7d3
KH
1554
1555/* for quick checking without looking up memcg */
1556atomic_t memcg_moving __read_mostly;
1557
c0ff4b85 1558static void mem_cgroup_start_move(struct mem_cgroup *memcg)
32047e2a 1559{
4331f7d3 1560 atomic_inc(&memcg_moving);
619d094b 1561 atomic_inc(&memcg->moving_account);
32047e2a
KH
1562 synchronize_rcu();
1563}
1564
c0ff4b85 1565static void mem_cgroup_end_move(struct mem_cgroup *memcg)
32047e2a 1566{
619d094b
KH
1567 /*
1568 * Now, mem_cgroup_clear_mc() may call this function with NULL.
1569 * We check NULL in callee rather than caller.
1570 */
4331f7d3
KH
1571 if (memcg) {
1572 atomic_dec(&memcg_moving);
619d094b 1573 atomic_dec(&memcg->moving_account);
4331f7d3 1574 }
32047e2a 1575}
619d094b 1576
32047e2a 1577/*
bdcbb659 1578 * A routine for checking "mem" is under move_account() or not.
32047e2a 1579 *
bdcbb659
QH
1580 * Checking a cgroup is mc.from or mc.to or under hierarchy of
1581 * moving cgroups. This is for waiting at high-memory pressure
1582 * caused by "move".
32047e2a 1583 */
c0ff4b85 1584static bool mem_cgroup_under_move(struct mem_cgroup *memcg)
4b534334 1585{
2bd9bb20
KH
1586 struct mem_cgroup *from;
1587 struct mem_cgroup *to;
4b534334 1588 bool ret = false;
2bd9bb20
KH
1589 /*
1590 * Unlike task_move routines, we access mc.to, mc.from not under
1591 * mutual exclusion by cgroup_mutex. Here, we take spinlock instead.
1592 */
1593 spin_lock(&mc.lock);
1594 from = mc.from;
1595 to = mc.to;
1596 if (!from)
1597 goto unlock;
3e92041d 1598
c0ff4b85
R
1599 ret = mem_cgroup_same_or_subtree(memcg, from)
1600 || mem_cgroup_same_or_subtree(memcg, to);
2bd9bb20
KH
1601unlock:
1602 spin_unlock(&mc.lock);
4b534334
KH
1603 return ret;
1604}
1605
c0ff4b85 1606static bool mem_cgroup_wait_acct_move(struct mem_cgroup *memcg)
4b534334
KH
1607{
1608 if (mc.moving_task && current != mc.moving_task) {
c0ff4b85 1609 if (mem_cgroup_under_move(memcg)) {
4b534334
KH
1610 DEFINE_WAIT(wait);
1611 prepare_to_wait(&mc.waitq, &wait, TASK_INTERRUPTIBLE);
1612 /* moving charge context might have finished. */
1613 if (mc.moving_task)
1614 schedule();
1615 finish_wait(&mc.waitq, &wait);
1616 return true;
1617 }
1618 }
1619 return false;
1620}
1621
312734c0
KH
1622/*
1623 * Take this lock when
1624 * - a code tries to modify page's memcg while it's USED.
1625 * - a code tries to modify page state accounting in a memcg.
312734c0
KH
1626 */
1627static void move_lock_mem_cgroup(struct mem_cgroup *memcg,
1628 unsigned long *flags)
1629{
1630 spin_lock_irqsave(&memcg->move_lock, *flags);
1631}
1632
1633static void move_unlock_mem_cgroup(struct mem_cgroup *memcg,
1634 unsigned long *flags)
1635{
1636 spin_unlock_irqrestore(&memcg->move_lock, *flags);
1637}
1638
58cf188e 1639#define K(x) ((x) << (PAGE_SHIFT-10))
e222432b 1640/**
58cf188e 1641 * mem_cgroup_print_oom_info: Print OOM information relevant to memory controller.
e222432b
BS
1642 * @memcg: The memory cgroup that went over limit
1643 * @p: Task that is going to be killed
1644 *
1645 * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is
1646 * enabled
1647 */
1648void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
1649{
e61734c5 1650 /* oom_info_lock ensures that parallel ooms do not interleave */
08088cb9 1651 static DEFINE_MUTEX(oom_info_lock);
58cf188e
SZ
1652 struct mem_cgroup *iter;
1653 unsigned int i;
e222432b 1654
58cf188e 1655 if (!p)
e222432b
BS
1656 return;
1657
08088cb9 1658 mutex_lock(&oom_info_lock);
e222432b
BS
1659 rcu_read_lock();
1660
e61734c5
TH
1661 pr_info("Task in ");
1662 pr_cont_cgroup_path(task_cgroup(p, memory_cgrp_id));
1663 pr_info(" killed as a result of limit of ");
1664 pr_cont_cgroup_path(memcg->css.cgroup);
1665 pr_info("\n");
e222432b 1666
e222432b
BS
1667 rcu_read_unlock();
1668
d045197f 1669 pr_info("memory: usage %llukB, limit %llukB, failcnt %llu\n",
e222432b
BS
1670 res_counter_read_u64(&memcg->res, RES_USAGE) >> 10,
1671 res_counter_read_u64(&memcg->res, RES_LIMIT) >> 10,
1672 res_counter_read_u64(&memcg->res, RES_FAILCNT));
d045197f 1673 pr_info("memory+swap: usage %llukB, limit %llukB, failcnt %llu\n",
e222432b
BS
1674 res_counter_read_u64(&memcg->memsw, RES_USAGE) >> 10,
1675 res_counter_read_u64(&memcg->memsw, RES_LIMIT) >> 10,
1676 res_counter_read_u64(&memcg->memsw, RES_FAILCNT));
d045197f 1677 pr_info("kmem: usage %llukB, limit %llukB, failcnt %llu\n",
510fc4e1
GC
1678 res_counter_read_u64(&memcg->kmem, RES_USAGE) >> 10,
1679 res_counter_read_u64(&memcg->kmem, RES_LIMIT) >> 10,
1680 res_counter_read_u64(&memcg->kmem, RES_FAILCNT));
58cf188e
SZ
1681
1682 for_each_mem_cgroup_tree(iter, memcg) {
e61734c5
TH
1683 pr_info("Memory cgroup stats for ");
1684 pr_cont_cgroup_path(iter->css.cgroup);
58cf188e
SZ
1685 pr_cont(":");
1686
1687 for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
1688 if (i == MEM_CGROUP_STAT_SWAP && !do_swap_account)
1689 continue;
1690 pr_cont(" %s:%ldKB", mem_cgroup_stat_names[i],
1691 K(mem_cgroup_read_stat(iter, i)));
1692 }
1693
1694 for (i = 0; i < NR_LRU_LISTS; i++)
1695 pr_cont(" %s:%luKB", mem_cgroup_lru_names[i],
1696 K(mem_cgroup_nr_lru_pages(iter, BIT(i))));
1697
1698 pr_cont("\n");
1699 }
08088cb9 1700 mutex_unlock(&oom_info_lock);
e222432b
BS
1701}
1702
81d39c20
KH
1703/*
1704 * This function returns the number of memcg under hierarchy tree. Returns
1705 * 1(self count) if no children.
1706 */
c0ff4b85 1707static int mem_cgroup_count_children(struct mem_cgroup *memcg)
81d39c20
KH
1708{
1709 int num = 0;
7d74b06f
KH
1710 struct mem_cgroup *iter;
1711
c0ff4b85 1712 for_each_mem_cgroup_tree(iter, memcg)
7d74b06f 1713 num++;
81d39c20
KH
1714 return num;
1715}
1716
a63d83f4
DR
1717/*
1718 * Return the memory (and swap, if configured) limit for a memcg.
1719 */
9cbb78bb 1720static u64 mem_cgroup_get_limit(struct mem_cgroup *memcg)
a63d83f4
DR
1721{
1722 u64 limit;
a63d83f4 1723
f3e8eb70 1724 limit = res_counter_read_u64(&memcg->res, RES_LIMIT);
f3e8eb70 1725
a63d83f4 1726 /*
9a5a8f19 1727 * Do not consider swap space if we cannot swap due to swappiness
a63d83f4 1728 */
9a5a8f19
MH
1729 if (mem_cgroup_swappiness(memcg)) {
1730 u64 memsw;
1731
1732 limit += total_swap_pages << PAGE_SHIFT;
1733 memsw = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
1734
1735 /*
1736 * If memsw is finite and limits the amount of swap space
1737 * available to this memcg, return that limit.
1738 */
1739 limit = min(limit, memsw);
1740 }
1741
1742 return limit;
a63d83f4
DR
1743}
1744
19965460
DR
1745static void mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask,
1746 int order)
9cbb78bb
DR
1747{
1748 struct mem_cgroup *iter;
1749 unsigned long chosen_points = 0;
1750 unsigned long totalpages;
1751 unsigned int points = 0;
1752 struct task_struct *chosen = NULL;
1753
876aafbf 1754 /*
465adcf1
DR
1755 * If current has a pending SIGKILL or is exiting, then automatically
1756 * select it. The goal is to allow it to allocate so that it may
1757 * quickly exit and free its memory.
876aafbf 1758 */
465adcf1 1759 if (fatal_signal_pending(current) || current->flags & PF_EXITING) {
876aafbf
DR
1760 set_thread_flag(TIF_MEMDIE);
1761 return;
1762 }
1763
1764 check_panic_on_oom(CONSTRAINT_MEMCG, gfp_mask, order, NULL);
9cbb78bb
DR
1765 totalpages = mem_cgroup_get_limit(memcg) >> PAGE_SHIFT ? : 1;
1766 for_each_mem_cgroup_tree(iter, memcg) {
72ec7029 1767 struct css_task_iter it;
9cbb78bb
DR
1768 struct task_struct *task;
1769
72ec7029
TH
1770 css_task_iter_start(&iter->css, &it);
1771 while ((task = css_task_iter_next(&it))) {
9cbb78bb
DR
1772 switch (oom_scan_process_thread(task, totalpages, NULL,
1773 false)) {
1774 case OOM_SCAN_SELECT:
1775 if (chosen)
1776 put_task_struct(chosen);
1777 chosen = task;
1778 chosen_points = ULONG_MAX;
1779 get_task_struct(chosen);
1780 /* fall through */
1781 case OOM_SCAN_CONTINUE:
1782 continue;
1783 case OOM_SCAN_ABORT:
72ec7029 1784 css_task_iter_end(&it);
9cbb78bb
DR
1785 mem_cgroup_iter_break(memcg, iter);
1786 if (chosen)
1787 put_task_struct(chosen);
1788 return;
1789 case OOM_SCAN_OK:
1790 break;
1791 };
1792 points = oom_badness(task, memcg, NULL, totalpages);
d49ad935
DR
1793 if (!points || points < chosen_points)
1794 continue;
1795 /* Prefer thread group leaders for display purposes */
1796 if (points == chosen_points &&
1797 thread_group_leader(chosen))
1798 continue;
1799
1800 if (chosen)
1801 put_task_struct(chosen);
1802 chosen = task;
1803 chosen_points = points;
1804 get_task_struct(chosen);
9cbb78bb 1805 }
72ec7029 1806 css_task_iter_end(&it);
9cbb78bb
DR
1807 }
1808
1809 if (!chosen)
1810 return;
1811 points = chosen_points * 1000 / totalpages;
9cbb78bb
DR
1812 oom_kill_process(chosen, gfp_mask, order, points, totalpages, memcg,
1813 NULL, "Memory cgroup out of memory");
9cbb78bb
DR
1814}
1815
5660048c
JW
1816static unsigned long mem_cgroup_reclaim(struct mem_cgroup *memcg,
1817 gfp_t gfp_mask,
1818 unsigned long flags)
1819{
1820 unsigned long total = 0;
1821 bool noswap = false;
1822 int loop;
1823
1824 if (flags & MEM_CGROUP_RECLAIM_NOSWAP)
1825 noswap = true;
1826 if (!(flags & MEM_CGROUP_RECLAIM_SHRINK) && memcg->memsw_is_minimum)
1827 noswap = true;
1828
1829 for (loop = 0; loop < MEM_CGROUP_MAX_RECLAIM_LOOPS; loop++) {
1830 if (loop)
1831 drain_all_stock_async(memcg);
1832 total += try_to_free_mem_cgroup_pages(memcg, gfp_mask, noswap);
1833 /*
1834 * Allow limit shrinkers, which are triggered directly
1835 * by userspace, to catch signals and stop reclaim
1836 * after minimal progress, regardless of the margin.
1837 */
1838 if (total && (flags & MEM_CGROUP_RECLAIM_SHRINK))
1839 break;
1840 if (mem_cgroup_margin(memcg))
1841 break;
1842 /*
1843 * If nothing was reclaimed after two attempts, there
1844 * may be no reclaimable pages in this hierarchy.
1845 */
1846 if (loop && !total)
1847 break;
1848 }
1849 return total;
1850}
1851
4d0c066d
KH
1852/**
1853 * test_mem_cgroup_node_reclaimable
dad7557e 1854 * @memcg: the target memcg
4d0c066d
KH
1855 * @nid: the node ID to be checked.
1856 * @noswap : specify true here if the user wants flle only information.
1857 *
1858 * This function returns whether the specified memcg contains any
1859 * reclaimable pages on a node. Returns true if there are any reclaimable
1860 * pages in the node.
1861 */
c0ff4b85 1862static bool test_mem_cgroup_node_reclaimable(struct mem_cgroup *memcg,
4d0c066d
KH
1863 int nid, bool noswap)
1864{
c0ff4b85 1865 if (mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL_FILE))
4d0c066d
KH
1866 return true;
1867 if (noswap || !total_swap_pages)
1868 return false;
c0ff4b85 1869 if (mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL_ANON))
4d0c066d
KH
1870 return true;
1871 return false;
1872
1873}
bb4cc1a8 1874#if MAX_NUMNODES > 1
889976db
YH
1875
1876/*
1877 * Always updating the nodemask is not very good - even if we have an empty
1878 * list or the wrong list here, we can start from some node and traverse all
1879 * nodes based on the zonelist. So update the list loosely once per 10 secs.
1880 *
1881 */
c0ff4b85 1882static void mem_cgroup_may_update_nodemask(struct mem_cgroup *memcg)
889976db
YH
1883{
1884 int nid;
453a9bf3
KH
1885 /*
1886 * numainfo_events > 0 means there was at least NUMAINFO_EVENTS_TARGET
1887 * pagein/pageout changes since the last update.
1888 */
c0ff4b85 1889 if (!atomic_read(&memcg->numainfo_events))
453a9bf3 1890 return;
c0ff4b85 1891 if (atomic_inc_return(&memcg->numainfo_updating) > 1)
889976db
YH
1892 return;
1893
889976db 1894 /* make a nodemask where this memcg uses memory from */
31aaea4a 1895 memcg->scan_nodes = node_states[N_MEMORY];
889976db 1896
31aaea4a 1897 for_each_node_mask(nid, node_states[N_MEMORY]) {
889976db 1898
c0ff4b85
R
1899 if (!test_mem_cgroup_node_reclaimable(memcg, nid, false))
1900 node_clear(nid, memcg->scan_nodes);
889976db 1901 }
453a9bf3 1902
c0ff4b85
R
1903 atomic_set(&memcg->numainfo_events, 0);
1904 atomic_set(&memcg->numainfo_updating, 0);
889976db
YH
1905}
1906
1907/*
1908 * Selecting a node where we start reclaim from. Because what we need is just
1909 * reducing usage counter, start from anywhere is O,K. Considering
1910 * memory reclaim from current node, there are pros. and cons.
1911 *
1912 * Freeing memory from current node means freeing memory from a node which
1913 * we'll use or we've used. So, it may make LRU bad. And if several threads
1914 * hit limits, it will see a contention on a node. But freeing from remote
1915 * node means more costs for memory reclaim because of memory latency.
1916 *
1917 * Now, we use round-robin. Better algorithm is welcomed.
1918 */
c0ff4b85 1919int mem_cgroup_select_victim_node(struct mem_cgroup *memcg)
889976db
YH
1920{
1921 int node;
1922
c0ff4b85
R
1923 mem_cgroup_may_update_nodemask(memcg);
1924 node = memcg->last_scanned_node;
889976db 1925
c0ff4b85 1926 node = next_node(node, memcg->scan_nodes);
889976db 1927 if (node == MAX_NUMNODES)
c0ff4b85 1928 node = first_node(memcg->scan_nodes);
889976db
YH
1929 /*
1930 * We call this when we hit limit, not when pages are added to LRU.
1931 * No LRU may hold pages because all pages are UNEVICTABLE or
1932 * memcg is too small and all pages are not on LRU. In that case,
1933 * we use curret node.
1934 */
1935 if (unlikely(node == MAX_NUMNODES))
1936 node = numa_node_id();
1937
c0ff4b85 1938 memcg->last_scanned_node = node;
889976db
YH
1939 return node;
1940}
1941
bb4cc1a8
AM
1942/*
1943 * Check all nodes whether it contains reclaimable pages or not.
1944 * For quick scan, we make use of scan_nodes. This will allow us to skip
1945 * unused nodes. But scan_nodes is lazily updated and may not cotain
1946 * enough new information. We need to do double check.
1947 */
1948static bool mem_cgroup_reclaimable(struct mem_cgroup *memcg, bool noswap)
1949{
1950 int nid;
1951
1952 /*
1953 * quick check...making use of scan_node.
1954 * We can skip unused nodes.
1955 */
1956 if (!nodes_empty(memcg->scan_nodes)) {
1957 for (nid = first_node(memcg->scan_nodes);
1958 nid < MAX_NUMNODES;
1959 nid = next_node(nid, memcg->scan_nodes)) {
1960
1961 if (test_mem_cgroup_node_reclaimable(memcg, nid, noswap))
1962 return true;
1963 }
1964 }
1965 /*
1966 * Check rest of nodes.
1967 */
1968 for_each_node_state(nid, N_MEMORY) {
1969 if (node_isset(nid, memcg->scan_nodes))
1970 continue;
1971 if (test_mem_cgroup_node_reclaimable(memcg, nid, noswap))
1972 return true;
1973 }
1974 return false;
1975}
1976
889976db 1977#else
c0ff4b85 1978int mem_cgroup_select_victim_node(struct mem_cgroup *memcg)
889976db
YH
1979{
1980 return 0;
1981}
4d0c066d 1982
bb4cc1a8
AM
1983static bool mem_cgroup_reclaimable(struct mem_cgroup *memcg, bool noswap)
1984{
1985 return test_mem_cgroup_node_reclaimable(memcg, 0, noswap);
1986}
889976db
YH
1987#endif
1988
0608f43d
AM
1989static int mem_cgroup_soft_reclaim(struct mem_cgroup *root_memcg,
1990 struct zone *zone,
1991 gfp_t gfp_mask,
1992 unsigned long *total_scanned)
1993{
1994 struct mem_cgroup *victim = NULL;
1995 int total = 0;
1996 int loop = 0;
1997 unsigned long excess;
1998 unsigned long nr_scanned;
1999 struct mem_cgroup_reclaim_cookie reclaim = {
2000 .zone = zone,
2001 .priority = 0,
2002 };
2003
2004 excess = res_counter_soft_limit_excess(&root_memcg->res) >> PAGE_SHIFT;
2005
2006 while (1) {
2007 victim = mem_cgroup_iter(root_memcg, victim, &reclaim);
2008 if (!victim) {
2009 loop++;
2010 if (loop >= 2) {
2011 /*
2012 * If we have not been able to reclaim
2013 * anything, it might because there are
2014 * no reclaimable pages under this hierarchy
2015 */
2016 if (!total)
2017 break;
2018 /*
2019 * We want to do more targeted reclaim.
2020 * excess >> 2 is not to excessive so as to
2021 * reclaim too much, nor too less that we keep
2022 * coming back to reclaim from this cgroup
2023 */
2024 if (total >= (excess >> 2) ||
2025 (loop > MEM_CGROUP_MAX_RECLAIM_LOOPS))
2026 break;
2027 }
2028 continue;
2029 }
2030 if (!mem_cgroup_reclaimable(victim, false))
2031 continue;
2032 total += mem_cgroup_shrink_node_zone(victim, gfp_mask, false,
2033 zone, &nr_scanned);
2034 *total_scanned += nr_scanned;
2035 if (!res_counter_soft_limit_excess(&root_memcg->res))
2036 break;
6d61ef40 2037 }
0608f43d
AM
2038 mem_cgroup_iter_break(root_memcg, victim);
2039 return total;
6d61ef40
BS
2040}
2041
0056f4e6
JW
2042#ifdef CONFIG_LOCKDEP
2043static struct lockdep_map memcg_oom_lock_dep_map = {
2044 .name = "memcg_oom_lock",
2045};
2046#endif
2047
fb2a6fc5
JW
2048static DEFINE_SPINLOCK(memcg_oom_lock);
2049
867578cb
KH
2050/*
2051 * Check OOM-Killer is already running under our hierarchy.
2052 * If someone is running, return false.
2053 */
fb2a6fc5 2054static bool mem_cgroup_oom_trylock(struct mem_cgroup *memcg)
867578cb 2055{
79dfdacc 2056 struct mem_cgroup *iter, *failed = NULL;
a636b327 2057
fb2a6fc5
JW
2058 spin_lock(&memcg_oom_lock);
2059
9f3a0d09 2060 for_each_mem_cgroup_tree(iter, memcg) {
23751be0 2061 if (iter->oom_lock) {
79dfdacc
MH
2062 /*
2063 * this subtree of our hierarchy is already locked
2064 * so we cannot give a lock.
2065 */
79dfdacc 2066 failed = iter;
9f3a0d09
JW
2067 mem_cgroup_iter_break(memcg, iter);
2068 break;
23751be0
JW
2069 } else
2070 iter->oom_lock = true;
7d74b06f 2071 }
867578cb 2072
fb2a6fc5
JW
2073 if (failed) {
2074 /*
2075 * OK, we failed to lock the whole subtree so we have
2076 * to clean up what we set up to the failing subtree
2077 */
2078 for_each_mem_cgroup_tree(iter, memcg) {
2079 if (iter == failed) {
2080 mem_cgroup_iter_break(memcg, iter);
2081 break;
2082 }
2083 iter->oom_lock = false;
79dfdacc 2084 }
0056f4e6
JW
2085 } else
2086 mutex_acquire(&memcg_oom_lock_dep_map, 0, 1, _RET_IP_);
fb2a6fc5
JW
2087
2088 spin_unlock(&memcg_oom_lock);
2089
2090 return !failed;
a636b327 2091}
0b7f569e 2092
fb2a6fc5 2093static void mem_cgroup_oom_unlock(struct mem_cgroup *memcg)
0b7f569e 2094{
7d74b06f
KH
2095 struct mem_cgroup *iter;
2096
fb2a6fc5 2097 spin_lock(&memcg_oom_lock);
0056f4e6 2098 mutex_release(&memcg_oom_lock_dep_map, 1, _RET_IP_);
c0ff4b85 2099 for_each_mem_cgroup_tree(iter, memcg)
79dfdacc 2100 iter->oom_lock = false;
fb2a6fc5 2101 spin_unlock(&memcg_oom_lock);
79dfdacc
MH
2102}
2103
c0ff4b85 2104static void mem_cgroup_mark_under_oom(struct mem_cgroup *memcg)
79dfdacc
MH
2105{
2106 struct mem_cgroup *iter;
2107
c0ff4b85 2108 for_each_mem_cgroup_tree(iter, memcg)
79dfdacc
MH
2109 atomic_inc(&iter->under_oom);
2110}
2111
c0ff4b85 2112static void mem_cgroup_unmark_under_oom(struct mem_cgroup *memcg)
79dfdacc
MH
2113{
2114 struct mem_cgroup *iter;
2115
867578cb
KH
2116 /*
2117 * When a new child is created while the hierarchy is under oom,
2118 * mem_cgroup_oom_lock() may not be called. We have to use
2119 * atomic_add_unless() here.
2120 */
c0ff4b85 2121 for_each_mem_cgroup_tree(iter, memcg)
79dfdacc 2122 atomic_add_unless(&iter->under_oom, -1, 0);
0b7f569e
KH
2123}
2124
867578cb
KH
2125static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq);
2126
dc98df5a 2127struct oom_wait_info {
d79154bb 2128 struct mem_cgroup *memcg;
dc98df5a
KH
2129 wait_queue_t wait;
2130};
2131
2132static int memcg_oom_wake_function(wait_queue_t *wait,
2133 unsigned mode, int sync, void *arg)
2134{
d79154bb
HD
2135 struct mem_cgroup *wake_memcg = (struct mem_cgroup *)arg;
2136 struct mem_cgroup *oom_wait_memcg;
dc98df5a
KH
2137 struct oom_wait_info *oom_wait_info;
2138
2139 oom_wait_info = container_of(wait, struct oom_wait_info, wait);
d79154bb 2140 oom_wait_memcg = oom_wait_info->memcg;
dc98df5a 2141
dc98df5a 2142 /*
d79154bb 2143 * Both of oom_wait_info->memcg and wake_memcg are stable under us.
dc98df5a
KH
2144 * Then we can use css_is_ancestor without taking care of RCU.
2145 */
c0ff4b85
R
2146 if (!mem_cgroup_same_or_subtree(oom_wait_memcg, wake_memcg)
2147 && !mem_cgroup_same_or_subtree(wake_memcg, oom_wait_memcg))
dc98df5a 2148 return 0;
dc98df5a
KH
2149 return autoremove_wake_function(wait, mode, sync, arg);
2150}
2151
c0ff4b85 2152static void memcg_wakeup_oom(struct mem_cgroup *memcg)
dc98df5a 2153{
3812c8c8 2154 atomic_inc(&memcg->oom_wakeups);
c0ff4b85
R
2155 /* for filtering, pass "memcg" as argument. */
2156 __wake_up(&memcg_oom_waitq, TASK_NORMAL, 0, memcg);
dc98df5a
KH
2157}
2158
c0ff4b85 2159static void memcg_oom_recover(struct mem_cgroup *memcg)
3c11ecf4 2160{
c0ff4b85
R
2161 if (memcg && atomic_read(&memcg->under_oom))
2162 memcg_wakeup_oom(memcg);
3c11ecf4
KH
2163}
2164
3812c8c8 2165static void mem_cgroup_oom(struct mem_cgroup *memcg, gfp_t mask, int order)
0b7f569e 2166{
3812c8c8
JW
2167 if (!current->memcg_oom.may_oom)
2168 return;
867578cb 2169 /*
49426420
JW
2170 * We are in the middle of the charge context here, so we
2171 * don't want to block when potentially sitting on a callstack
2172 * that holds all kinds of filesystem and mm locks.
2173 *
2174 * Also, the caller may handle a failed allocation gracefully
2175 * (like optional page cache readahead) and so an OOM killer
2176 * invocation might not even be necessary.
2177 *
2178 * That's why we don't do anything here except remember the
2179 * OOM context and then deal with it at the end of the page
2180 * fault when the stack is unwound, the locks are released,
2181 * and when we know whether the fault was overall successful.
867578cb 2182 */
49426420
JW
2183 css_get(&memcg->css);
2184 current->memcg_oom.memcg = memcg;
2185 current->memcg_oom.gfp_mask = mask;
2186 current->memcg_oom.order = order;
3812c8c8
JW
2187}
2188
2189/**
2190 * mem_cgroup_oom_synchronize - complete memcg OOM handling
49426420 2191 * @handle: actually kill/wait or just clean up the OOM state
3812c8c8 2192 *
49426420
JW
2193 * This has to be called at the end of a page fault if the memcg OOM
2194 * handler was enabled.
3812c8c8 2195 *
49426420 2196 * Memcg supports userspace OOM handling where failed allocations must
3812c8c8
JW
2197 * sleep on a waitqueue until the userspace task resolves the
2198 * situation. Sleeping directly in the charge context with all kinds
2199 * of locks held is not a good idea, instead we remember an OOM state
2200 * in the task and mem_cgroup_oom_synchronize() has to be called at
49426420 2201 * the end of the page fault to complete the OOM handling.
3812c8c8
JW
2202 *
2203 * Returns %true if an ongoing memcg OOM situation was detected and
49426420 2204 * completed, %false otherwise.
3812c8c8 2205 */
49426420 2206bool mem_cgroup_oom_synchronize(bool handle)
3812c8c8 2207{
49426420 2208 struct mem_cgroup *memcg = current->memcg_oom.memcg;
3812c8c8 2209 struct oom_wait_info owait;
49426420 2210 bool locked;
3812c8c8
JW
2211
2212 /* OOM is global, do not handle */
3812c8c8 2213 if (!memcg)
49426420 2214 return false;
3812c8c8 2215
49426420
JW
2216 if (!handle)
2217 goto cleanup;
3812c8c8
JW
2218
2219 owait.memcg = memcg;
2220 owait.wait.flags = 0;
2221 owait.wait.func = memcg_oom_wake_function;
2222 owait.wait.private = current;
2223 INIT_LIST_HEAD(&owait.wait.task_list);
867578cb 2224
3812c8c8 2225 prepare_to_wait(&memcg_oom_waitq, &owait.wait, TASK_KILLABLE);
49426420
JW
2226 mem_cgroup_mark_under_oom(memcg);
2227
2228 locked = mem_cgroup_oom_trylock(memcg);
2229
2230 if (locked)
2231 mem_cgroup_oom_notify(memcg);
2232
2233 if (locked && !memcg->oom_kill_disable) {
2234 mem_cgroup_unmark_under_oom(memcg);
2235 finish_wait(&memcg_oom_waitq, &owait.wait);
2236 mem_cgroup_out_of_memory(memcg, current->memcg_oom.gfp_mask,
2237 current->memcg_oom.order);
2238 } else {
3812c8c8 2239 schedule();
49426420
JW
2240 mem_cgroup_unmark_under_oom(memcg);
2241 finish_wait(&memcg_oom_waitq, &owait.wait);
2242 }
2243
2244 if (locked) {
fb2a6fc5
JW
2245 mem_cgroup_oom_unlock(memcg);
2246 /*
2247 * There is no guarantee that an OOM-lock contender
2248 * sees the wakeups triggered by the OOM kill
2249 * uncharges. Wake any sleepers explicitely.
2250 */
2251 memcg_oom_recover(memcg);
2252 }
49426420
JW
2253cleanup:
2254 current->memcg_oom.memcg = NULL;
3812c8c8 2255 css_put(&memcg->css);
867578cb 2256 return true;
0b7f569e
KH
2257}
2258
d69b042f 2259/*
b5ffc856 2260 * Used to update mapped file or writeback or other statistics.
32047e2a
KH
2261 *
2262 * Notes: Race condition
2263 *
b5ffc856 2264 * We usually use lock_page_cgroup() for accessing page_cgroup member but
32047e2a
KH
2265 * it tends to be costly. But considering some conditions, we doesn't need
2266 * to do so _always_.
2267 *
2268 * Considering "charge", lock_page_cgroup() is not required because all
2269 * file-stat operations happen after a page is attached to radix-tree. There
2270 * are no race with "charge".
2271 *
2272 * Considering "uncharge", we know that memcg doesn't clear pc->mem_cgroup
2273 * at "uncharge" intentionally. So, we always see valid pc->mem_cgroup even
2274 * if there are race with "uncharge". Statistics itself is properly handled
2275 * by flags.
2276 *
2277 * Considering "move", this is an only case we see a race. To make the race
b5ffc856
QH
2278 * small, we check memcg->moving_account and detect there are possibility
2279 * of race or not. If there is, we take a lock.
d69b042f 2280 */
26174efd 2281
89c06bd5
KH
2282void __mem_cgroup_begin_update_page_stat(struct page *page,
2283 bool *locked, unsigned long *flags)
2284{
2285 struct mem_cgroup *memcg;
2286 struct page_cgroup *pc;
2287
2288 pc = lookup_page_cgroup(page);
2289again:
2290 memcg = pc->mem_cgroup;
2291 if (unlikely(!memcg || !PageCgroupUsed(pc)))
2292 return;
2293 /*
2294 * If this memory cgroup is not under account moving, we don't
da92c47d 2295 * need to take move_lock_mem_cgroup(). Because we already hold
89c06bd5 2296 * rcu_read_lock(), any calls to move_account will be delayed until
bdcbb659 2297 * rcu_read_unlock().
89c06bd5 2298 */
bdcbb659
QH
2299 VM_BUG_ON(!rcu_read_lock_held());
2300 if (atomic_read(&memcg->moving_account) <= 0)
89c06bd5
KH
2301 return;
2302
2303 move_lock_mem_cgroup(memcg, flags);
2304 if (memcg != pc->mem_cgroup || !PageCgroupUsed(pc)) {
2305 move_unlock_mem_cgroup(memcg, flags);
2306 goto again;
2307 }
2308 *locked = true;
2309}
2310
2311void __mem_cgroup_end_update_page_stat(struct page *page, unsigned long *flags)
2312{
2313 struct page_cgroup *pc = lookup_page_cgroup(page);
2314
2315 /*
2316 * It's guaranteed that pc->mem_cgroup never changes while
2317 * lock is held because a routine modifies pc->mem_cgroup
da92c47d 2318 * should take move_lock_mem_cgroup().
89c06bd5
KH
2319 */
2320 move_unlock_mem_cgroup(pc->mem_cgroup, flags);
2321}
2322
2a7106f2 2323void mem_cgroup_update_page_stat(struct page *page,
68b4876d 2324 enum mem_cgroup_stat_index idx, int val)
d69b042f 2325{
c0ff4b85 2326 struct mem_cgroup *memcg;
32047e2a 2327 struct page_cgroup *pc = lookup_page_cgroup(page);
dbd4ea78 2328 unsigned long uninitialized_var(flags);
d69b042f 2329
cfa44946 2330 if (mem_cgroup_disabled())
d69b042f 2331 return;
89c06bd5 2332
658b72c5 2333 VM_BUG_ON(!rcu_read_lock_held());
c0ff4b85
R
2334 memcg = pc->mem_cgroup;
2335 if (unlikely(!memcg || !PageCgroupUsed(pc)))
89c06bd5 2336 return;
26174efd 2337
c0ff4b85 2338 this_cpu_add(memcg->stat->count[idx], val);
d69b042f 2339}
26174efd 2340
cdec2e42
KH
2341/*
2342 * size of first charge trial. "32" comes from vmscan.c's magic value.
2343 * TODO: maybe necessary to use big numbers in big irons.
2344 */
7ec99d62 2345#define CHARGE_BATCH 32U
cdec2e42
KH
2346struct memcg_stock_pcp {
2347 struct mem_cgroup *cached; /* this never be root cgroup */
11c9ea4e 2348 unsigned int nr_pages;
cdec2e42 2349 struct work_struct work;
26fe6168 2350 unsigned long flags;
a0db00fc 2351#define FLUSHING_CACHED_CHARGE 0
cdec2e42
KH
2352};
2353static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock);
9f50fad6 2354static DEFINE_MUTEX(percpu_charge_mutex);
cdec2e42 2355
a0956d54
SS
2356/**
2357 * consume_stock: Try to consume stocked charge on this cpu.
2358 * @memcg: memcg to consume from.
2359 * @nr_pages: how many pages to charge.
2360 *
2361 * The charges will only happen if @memcg matches the current cpu's memcg
2362 * stock, and at least @nr_pages are available in that stock. Failure to
2363 * service an allocation will refill the stock.
2364 *
2365 * returns true if successful, false otherwise.
cdec2e42 2366 */
a0956d54 2367static bool consume_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
cdec2e42
KH
2368{
2369 struct memcg_stock_pcp *stock;
2370 bool ret = true;
2371
a0956d54
SS
2372 if (nr_pages > CHARGE_BATCH)
2373 return false;
2374
cdec2e42 2375 stock = &get_cpu_var(memcg_stock);
a0956d54
SS
2376 if (memcg == stock->cached && stock->nr_pages >= nr_pages)
2377 stock->nr_pages -= nr_pages;
cdec2e42
KH
2378 else /* need to call res_counter_charge */
2379 ret = false;
2380 put_cpu_var(memcg_stock);
2381 return ret;
2382}
2383
2384/*
2385 * Returns stocks cached in percpu to res_counter and reset cached information.
2386 */
2387static void drain_stock(struct memcg_stock_pcp *stock)
2388{
2389 struct mem_cgroup *old = stock->cached;
2390
11c9ea4e
JW
2391 if (stock->nr_pages) {
2392 unsigned long bytes = stock->nr_pages * PAGE_SIZE;
2393
2394 res_counter_uncharge(&old->res, bytes);
cdec2e42 2395 if (do_swap_account)
11c9ea4e
JW
2396 res_counter_uncharge(&old->memsw, bytes);
2397 stock->nr_pages = 0;
cdec2e42
KH
2398 }
2399 stock->cached = NULL;
cdec2e42
KH
2400}
2401
2402/*
2403 * This must be called under preempt disabled or must be called by
2404 * a thread which is pinned to local cpu.
2405 */
2406static void drain_local_stock(struct work_struct *dummy)
2407{
7c8e0181 2408 struct memcg_stock_pcp *stock = this_cpu_ptr(&memcg_stock);
cdec2e42 2409 drain_stock(stock);
26fe6168 2410 clear_bit(FLUSHING_CACHED_CHARGE, &stock->flags);
cdec2e42
KH
2411}
2412
e4777496
MH
2413static void __init memcg_stock_init(void)
2414{
2415 int cpu;
2416
2417 for_each_possible_cpu(cpu) {
2418 struct memcg_stock_pcp *stock =
2419 &per_cpu(memcg_stock, cpu);
2420 INIT_WORK(&stock->work, drain_local_stock);
2421 }
2422}
2423
cdec2e42
KH
2424/*
2425 * Cache charges(val) which is from res_counter, to local per_cpu area.
320cc51d 2426 * This will be consumed by consume_stock() function, later.
cdec2e42 2427 */
c0ff4b85 2428static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
cdec2e42
KH
2429{
2430 struct memcg_stock_pcp *stock = &get_cpu_var(memcg_stock);
2431
c0ff4b85 2432 if (stock->cached != memcg) { /* reset if necessary */
cdec2e42 2433 drain_stock(stock);
c0ff4b85 2434 stock->cached = memcg;
cdec2e42 2435 }
11c9ea4e 2436 stock->nr_pages += nr_pages;
cdec2e42
KH
2437 put_cpu_var(memcg_stock);
2438}
2439
2440/*
c0ff4b85 2441 * Drains all per-CPU charge caches for given root_memcg resp. subtree
d38144b7
MH
2442 * of the hierarchy under it. sync flag says whether we should block
2443 * until the work is done.
cdec2e42 2444 */
c0ff4b85 2445static void drain_all_stock(struct mem_cgroup *root_memcg, bool sync)
cdec2e42 2446{
26fe6168 2447 int cpu, curcpu;
d38144b7 2448
cdec2e42 2449 /* Notify other cpus that system-wide "drain" is running */
cdec2e42 2450 get_online_cpus();
5af12d0e 2451 curcpu = get_cpu();
cdec2e42
KH
2452 for_each_online_cpu(cpu) {
2453 struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
c0ff4b85 2454 struct mem_cgroup *memcg;
26fe6168 2455
c0ff4b85
R
2456 memcg = stock->cached;
2457 if (!memcg || !stock->nr_pages)
26fe6168 2458 continue;
c0ff4b85 2459 if (!mem_cgroup_same_or_subtree(root_memcg, memcg))
3e92041d 2460 continue;
d1a05b69
MH
2461 if (!test_and_set_bit(FLUSHING_CACHED_CHARGE, &stock->flags)) {
2462 if (cpu == curcpu)
2463 drain_local_stock(&stock->work);
2464 else
2465 schedule_work_on(cpu, &stock->work);
2466 }
cdec2e42 2467 }
5af12d0e 2468 put_cpu();
d38144b7
MH
2469
2470 if (!sync)
2471 goto out;
2472
2473 for_each_online_cpu(cpu) {
2474 struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
9f50fad6 2475 if (test_bit(FLUSHING_CACHED_CHARGE, &stock->flags))
d38144b7
MH
2476 flush_work(&stock->work);
2477 }
2478out:
f894ffa8 2479 put_online_cpus();
d38144b7
MH
2480}
2481
2482/*
2483 * Tries to drain stocked charges in other cpus. This function is asynchronous
2484 * and just put a work per cpu for draining localy on each cpu. Caller can
2485 * expects some charges will be back to res_counter later but cannot wait for
2486 * it.
2487 */
c0ff4b85 2488static void drain_all_stock_async(struct mem_cgroup *root_memcg)
d38144b7 2489{
9f50fad6
MH
2490 /*
2491 * If someone calls draining, avoid adding more kworker runs.
2492 */
2493 if (!mutex_trylock(&percpu_charge_mutex))
2494 return;
c0ff4b85 2495 drain_all_stock(root_memcg, false);
9f50fad6 2496 mutex_unlock(&percpu_charge_mutex);
cdec2e42
KH
2497}
2498
2499/* This is a synchronous drain interface. */
c0ff4b85 2500static void drain_all_stock_sync(struct mem_cgroup *root_memcg)
cdec2e42
KH
2501{
2502 /* called when force_empty is called */
9f50fad6 2503 mutex_lock(&percpu_charge_mutex);
c0ff4b85 2504 drain_all_stock(root_memcg, true);
9f50fad6 2505 mutex_unlock(&percpu_charge_mutex);
cdec2e42
KH
2506}
2507
711d3d2c
KH
2508/*
2509 * This function drains percpu counter value from DEAD cpu and
2510 * move it to local cpu. Note that this function can be preempted.
2511 */
c0ff4b85 2512static void mem_cgroup_drain_pcp_counter(struct mem_cgroup *memcg, int cpu)
711d3d2c
KH
2513{
2514 int i;
2515
c0ff4b85 2516 spin_lock(&memcg->pcp_counter_lock);
6104621d 2517 for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
c0ff4b85 2518 long x = per_cpu(memcg->stat->count[i], cpu);
711d3d2c 2519
c0ff4b85
R
2520 per_cpu(memcg->stat->count[i], cpu) = 0;
2521 memcg->nocpu_base.count[i] += x;
711d3d2c 2522 }
e9f8974f 2523 for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++) {
c0ff4b85 2524 unsigned long x = per_cpu(memcg->stat->events[i], cpu);
e9f8974f 2525
c0ff4b85
R
2526 per_cpu(memcg->stat->events[i], cpu) = 0;
2527 memcg->nocpu_base.events[i] += x;
e9f8974f 2528 }
c0ff4b85 2529 spin_unlock(&memcg->pcp_counter_lock);
711d3d2c
KH
2530}
2531
0db0628d 2532static int memcg_cpu_hotplug_callback(struct notifier_block *nb,
cdec2e42
KH
2533 unsigned long action,
2534 void *hcpu)
2535{
2536 int cpu = (unsigned long)hcpu;
2537 struct memcg_stock_pcp *stock;
711d3d2c 2538 struct mem_cgroup *iter;
cdec2e42 2539
619d094b 2540 if (action == CPU_ONLINE)
1489ebad 2541 return NOTIFY_OK;
1489ebad 2542
d833049b 2543 if (action != CPU_DEAD && action != CPU_DEAD_FROZEN)
cdec2e42 2544 return NOTIFY_OK;
711d3d2c 2545
9f3a0d09 2546 for_each_mem_cgroup(iter)
711d3d2c
KH
2547 mem_cgroup_drain_pcp_counter(iter, cpu);
2548
cdec2e42
KH
2549 stock = &per_cpu(memcg_stock, cpu);
2550 drain_stock(stock);
2551 return NOTIFY_OK;
2552}
2553
4b534334 2554
6d1fdc48 2555/* See mem_cgroup_try_charge() for details */
4b534334
KH
2556enum {
2557 CHARGE_OK, /* success */
2558 CHARGE_RETRY, /* need to retry but retry is not bad */
2559 CHARGE_NOMEM, /* we can't do more. return -ENOMEM */
2560 CHARGE_WOULDBLOCK, /* GFP_WAIT wasn't set and no enough res. */
4b534334
KH
2561};
2562
c0ff4b85 2563static int mem_cgroup_do_charge(struct mem_cgroup *memcg, gfp_t gfp_mask,
4c9c5359 2564 unsigned int nr_pages, unsigned int min_pages,
3812c8c8 2565 bool invoke_oom)
4b534334 2566{
7ec99d62 2567 unsigned long csize = nr_pages * PAGE_SIZE;
4b534334
KH
2568 struct mem_cgroup *mem_over_limit;
2569 struct res_counter *fail_res;
2570 unsigned long flags = 0;
2571 int ret;
2572
c0ff4b85 2573 ret = res_counter_charge(&memcg->res, csize, &fail_res);
4b534334
KH
2574
2575 if (likely(!ret)) {
2576 if (!do_swap_account)
2577 return CHARGE_OK;
c0ff4b85 2578 ret = res_counter_charge(&memcg->memsw, csize, &fail_res);
4b534334
KH
2579 if (likely(!ret))
2580 return CHARGE_OK;
2581
c0ff4b85 2582 res_counter_uncharge(&memcg->res, csize);
4b534334
KH
2583 mem_over_limit = mem_cgroup_from_res_counter(fail_res, memsw);
2584 flags |= MEM_CGROUP_RECLAIM_NOSWAP;
2585 } else
2586 mem_over_limit = mem_cgroup_from_res_counter(fail_res, res);
9221edb7 2587 /*
9221edb7
JW
2588 * Never reclaim on behalf of optional batching, retry with a
2589 * single page instead.
2590 */
4c9c5359 2591 if (nr_pages > min_pages)
4b534334
KH
2592 return CHARGE_RETRY;
2593
2594 if (!(gfp_mask & __GFP_WAIT))
2595 return CHARGE_WOULDBLOCK;
2596
4c9c5359
SS
2597 if (gfp_mask & __GFP_NORETRY)
2598 return CHARGE_NOMEM;
2599
5660048c 2600 ret = mem_cgroup_reclaim(mem_over_limit, gfp_mask, flags);
7ec99d62 2601 if (mem_cgroup_margin(mem_over_limit) >= nr_pages)
19942822 2602 return CHARGE_RETRY;
4b534334 2603 /*
19942822
JW
2604 * Even though the limit is exceeded at this point, reclaim
2605 * may have been able to free some pages. Retry the charge
2606 * before killing the task.
2607 *
2608 * Only for regular pages, though: huge pages are rather
2609 * unlikely to succeed so close to the limit, and we fall back
2610 * to regular pages anyway in case of failure.
4b534334 2611 */
4c9c5359 2612 if (nr_pages <= (1 << PAGE_ALLOC_COSTLY_ORDER) && ret)
4b534334
KH
2613 return CHARGE_RETRY;
2614
2615 /*
2616 * At task move, charge accounts can be doubly counted. So, it's
2617 * better to wait until the end of task_move if something is going on.
2618 */
2619 if (mem_cgroup_wait_acct_move(mem_over_limit))
2620 return CHARGE_RETRY;
2621
3812c8c8
JW
2622 if (invoke_oom)
2623 mem_cgroup_oom(mem_over_limit, gfp_mask, get_order(csize));
4b534334 2624
3812c8c8 2625 return CHARGE_NOMEM;
4b534334
KH
2626}
2627
6d1fdc48
JW
2628/**
2629 * mem_cgroup_try_charge - try charging a memcg
2630 * @memcg: memcg to charge
2631 * @nr_pages: number of pages to charge
2632 * @oom: trigger OOM if reclaim fails
38c5d72f 2633 *
6d1fdc48
JW
2634 * Returns 0 if @memcg was charged successfully, -EINTR if the charge
2635 * was bypassed to root_mem_cgroup, and -ENOMEM if the charge failed.
8a9f3ccd 2636 */
6d1fdc48
JW
2637static int mem_cgroup_try_charge(struct mem_cgroup *memcg,
2638 gfp_t gfp_mask,
2639 unsigned int nr_pages,
2640 bool oom)
8a9f3ccd 2641{
7ec99d62 2642 unsigned int batch = max(CHARGE_BATCH, nr_pages);
4b534334 2643 int nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES;
4b534334 2644 int ret;
a636b327 2645
6d1fdc48
JW
2646 if (mem_cgroup_is_root(memcg))
2647 goto done;
867578cb 2648 /*
6d1fdc48
JW
2649 * Unlike in global OOM situations, memcg is not in a physical
2650 * memory shortage. Allow dying and OOM-killed tasks to
2651 * bypass the last charges so that they can exit quickly and
2652 * free their memory.
867578cb 2653 */
6d1fdc48 2654 if (unlikely(test_thread_flag(TIF_MEMDIE) ||
d8dc595c
MH
2655 fatal_signal_pending(current) ||
2656 current->flags & PF_EXITING))
867578cb 2657 goto bypass;
a636b327 2658
49426420 2659 if (unlikely(task_in_memcg_oom(current)))
1f14c1ac 2660 goto nomem;
49426420 2661
a0d8b00a
JW
2662 if (gfp_mask & __GFP_NOFAIL)
2663 oom = false;
f75ca962 2664again:
b6b6cc72
MH
2665 if (consume_stock(memcg, nr_pages))
2666 goto done;
8a9f3ccd 2667
4b534334 2668 do {
3812c8c8 2669 bool invoke_oom = oom && !nr_oom_retries;
7a81b88c 2670
4b534334 2671 /* If killed, bypass charge */
6d1fdc48 2672 if (fatal_signal_pending(current))
4b534334 2673 goto bypass;
6d61ef40 2674
3812c8c8
JW
2675 ret = mem_cgroup_do_charge(memcg, gfp_mask, batch,
2676 nr_pages, invoke_oom);
4b534334
KH
2677 switch (ret) {
2678 case CHARGE_OK:
2679 break;
2680 case CHARGE_RETRY: /* not in OOM situation but retry */
7ec99d62 2681 batch = nr_pages;
f75ca962 2682 goto again;
4b534334
KH
2683 case CHARGE_WOULDBLOCK: /* !__GFP_WAIT */
2684 goto nomem;
2685 case CHARGE_NOMEM: /* OOM routine works */
6d1fdc48 2686 if (!oom || invoke_oom)
867578cb 2687 goto nomem;
4b534334
KH
2688 nr_oom_retries--;
2689 break;
66e1707b 2690 }
4b534334
KH
2691 } while (ret != CHARGE_OK);
2692
7ec99d62 2693 if (batch > nr_pages)
c0ff4b85 2694 refill_stock(memcg, batch - nr_pages);
0c3e73e8 2695done:
7a81b88c
KH
2696 return 0;
2697nomem:
6d1fdc48 2698 if (!(gfp_mask & __GFP_NOFAIL))
3168ecbe 2699 return -ENOMEM;
867578cb 2700bypass:
38c5d72f 2701 return -EINTR;
7a81b88c 2702}
8a9f3ccd 2703
6d1fdc48
JW
2704/**
2705 * mem_cgroup_try_charge_mm - try charging a mm
2706 * @mm: mm_struct to charge
2707 * @nr_pages: number of pages to charge
2708 * @oom: trigger OOM if reclaim fails
2709 *
2710 * Returns the charged mem_cgroup associated with the given mm_struct or
2711 * NULL the charge failed.
2712 */
2713static struct mem_cgroup *mem_cgroup_try_charge_mm(struct mm_struct *mm,
2714 gfp_t gfp_mask,
2715 unsigned int nr_pages,
2716 bool oom)
2717
2718{
2719 struct mem_cgroup *memcg;
2720 int ret;
2721
2722 memcg = get_mem_cgroup_from_mm(mm);
2723 ret = mem_cgroup_try_charge(memcg, gfp_mask, nr_pages, oom);
2724 css_put(&memcg->css);
2725 if (ret == -EINTR)
2726 memcg = root_mem_cgroup;
2727 else if (ret)
2728 memcg = NULL;
2729
2730 return memcg;
2731}
2732
a3032a2c
DN
2733/*
2734 * Somemtimes we have to undo a charge we got by try_charge().
2735 * This function is for that and do uncharge, put css's refcnt.
2736 * gotten by try_charge().
2737 */
c0ff4b85 2738static void __mem_cgroup_cancel_charge(struct mem_cgroup *memcg,
e7018b8d 2739 unsigned int nr_pages)
a3032a2c 2740{
c0ff4b85 2741 if (!mem_cgroup_is_root(memcg)) {
e7018b8d
JW
2742 unsigned long bytes = nr_pages * PAGE_SIZE;
2743
c0ff4b85 2744 res_counter_uncharge(&memcg->res, bytes);
a3032a2c 2745 if (do_swap_account)
c0ff4b85 2746 res_counter_uncharge(&memcg->memsw, bytes);
a3032a2c 2747 }
854ffa8d
DN
2748}
2749
d01dd17f
KH
2750/*
2751 * Cancel chrages in this cgroup....doesn't propagate to parent cgroup.
2752 * This is useful when moving usage to parent cgroup.
2753 */
2754static void __mem_cgroup_cancel_local_charge(struct mem_cgroup *memcg,
2755 unsigned int nr_pages)
2756{
2757 unsigned long bytes = nr_pages * PAGE_SIZE;
2758
2759 if (mem_cgroup_is_root(memcg))
2760 return;
2761
2762 res_counter_uncharge_until(&memcg->res, memcg->res.parent, bytes);
2763 if (do_swap_account)
2764 res_counter_uncharge_until(&memcg->memsw,
2765 memcg->memsw.parent, bytes);
2766}
2767
a3b2d692
KH
2768/*
2769 * A helper function to get mem_cgroup from ID. must be called under
ec903c0c
TH
2770 * rcu_read_lock(). The caller is responsible for calling
2771 * css_tryget_online() if the mem_cgroup is used for charging. (dropping
2772 * refcnt from swap can be called against removed memcg.)
a3b2d692
KH
2773 */
2774static struct mem_cgroup *mem_cgroup_lookup(unsigned short id)
2775{
a3b2d692
KH
2776 /* ID 0 is unused ID */
2777 if (!id)
2778 return NULL;
34c00c31 2779 return mem_cgroup_from_id(id);
a3b2d692
KH
2780}
2781
e42d9d5d 2782struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page)
b5a84319 2783{
c0ff4b85 2784 struct mem_cgroup *memcg = NULL;
3c776e64 2785 struct page_cgroup *pc;
a3b2d692 2786 unsigned short id;
b5a84319
KH
2787 swp_entry_t ent;
2788
309381fe 2789 VM_BUG_ON_PAGE(!PageLocked(page), page);
3c776e64 2790
3c776e64 2791 pc = lookup_page_cgroup(page);
c0bd3f63 2792 lock_page_cgroup(pc);
a3b2d692 2793 if (PageCgroupUsed(pc)) {
c0ff4b85 2794 memcg = pc->mem_cgroup;
ec903c0c 2795 if (memcg && !css_tryget_online(&memcg->css))
c0ff4b85 2796 memcg = NULL;
e42d9d5d 2797 } else if (PageSwapCache(page)) {
3c776e64 2798 ent.val = page_private(page);
9fb4b7cc 2799 id = lookup_swap_cgroup_id(ent);
a3b2d692 2800 rcu_read_lock();
c0ff4b85 2801 memcg = mem_cgroup_lookup(id);
ec903c0c 2802 if (memcg && !css_tryget_online(&memcg->css))
c0ff4b85 2803 memcg = NULL;
a3b2d692 2804 rcu_read_unlock();
3c776e64 2805 }
c0bd3f63 2806 unlock_page_cgroup(pc);
c0ff4b85 2807 return memcg;
b5a84319
KH
2808}
2809
c0ff4b85 2810static void __mem_cgroup_commit_charge(struct mem_cgroup *memcg,
5564e88b 2811 struct page *page,
7ec99d62 2812 unsigned int nr_pages,
9ce70c02
HD
2813 enum charge_type ctype,
2814 bool lrucare)
7a81b88c 2815{
ce587e65 2816 struct page_cgroup *pc = lookup_page_cgroup(page);
9ce70c02 2817 struct zone *uninitialized_var(zone);
fa9add64 2818 struct lruvec *lruvec;
9ce70c02 2819 bool was_on_lru = false;
b2402857 2820 bool anon;
9ce70c02 2821
ca3e0214 2822 lock_page_cgroup(pc);
309381fe 2823 VM_BUG_ON_PAGE(PageCgroupUsed(pc), page);
ca3e0214
KH
2824 /*
2825 * we don't need page_cgroup_lock about tail pages, becase they are not
2826 * accessed by any other context at this point.
2827 */
9ce70c02
HD
2828
2829 /*
2830 * In some cases, SwapCache and FUSE(splice_buf->radixtree), the page
2831 * may already be on some other mem_cgroup's LRU. Take care of it.
2832 */
2833 if (lrucare) {
2834 zone = page_zone(page);
2835 spin_lock_irq(&zone->lru_lock);
2836 if (PageLRU(page)) {
fa9add64 2837 lruvec = mem_cgroup_zone_lruvec(zone, pc->mem_cgroup);
9ce70c02 2838 ClearPageLRU(page);
fa9add64 2839 del_page_from_lru_list(page, lruvec, page_lru(page));
9ce70c02
HD
2840 was_on_lru = true;
2841 }
2842 }
2843
c0ff4b85 2844 pc->mem_cgroup = memcg;
261fb61a
KH
2845 /*
2846 * We access a page_cgroup asynchronously without lock_page_cgroup().
2847 * Especially when a page_cgroup is taken from a page, pc->mem_cgroup
2848 * is accessed after testing USED bit. To make pc->mem_cgroup visible
2849 * before USED bit, we need memory barrier here.
2850 * See mem_cgroup_add_lru_list(), etc.
f894ffa8 2851 */
08e552c6 2852 smp_wmb();
b2402857 2853 SetPageCgroupUsed(pc);
3be91277 2854
9ce70c02
HD
2855 if (lrucare) {
2856 if (was_on_lru) {
fa9add64 2857 lruvec = mem_cgroup_zone_lruvec(zone, pc->mem_cgroup);
309381fe 2858 VM_BUG_ON_PAGE(PageLRU(page), page);
9ce70c02 2859 SetPageLRU(page);
fa9add64 2860 add_page_to_lru_list(page, lruvec, page_lru(page));
9ce70c02
HD
2861 }
2862 spin_unlock_irq(&zone->lru_lock);
2863 }
2864
41326c17 2865 if (ctype == MEM_CGROUP_CHARGE_TYPE_ANON)
b2402857
KH
2866 anon = true;
2867 else
2868 anon = false;
2869
b070e65c 2870 mem_cgroup_charge_statistics(memcg, page, anon, nr_pages);
52d4b9ac 2871 unlock_page_cgroup(pc);
9ce70c02 2872
430e4863 2873 /*
bb4cc1a8
AM
2874 * "charge_statistics" updated event counter. Then, check it.
2875 * Insert ancestor (and ancestor's ancestors), to softlimit RB-tree.
2876 * if they exceeds softlimit.
430e4863 2877 */
c0ff4b85 2878 memcg_check_events(memcg, page);
7a81b88c 2879}
66e1707b 2880
7cf27982
GC
2881static DEFINE_MUTEX(set_limit_mutex);
2882
7ae1e1d0 2883#ifdef CONFIG_MEMCG_KMEM
bd673145
VD
2884/*
2885 * The memcg_slab_mutex is held whenever a per memcg kmem cache is created or
2886 * destroyed. It protects memcg_caches arrays and memcg_slab_caches lists.
2887 */
2888static DEFINE_MUTEX(memcg_slab_mutex);
2889
d6441637
VD
2890static DEFINE_MUTEX(activate_kmem_mutex);
2891
7ae1e1d0
GC
2892static inline bool memcg_can_account_kmem(struct mem_cgroup *memcg)
2893{
2894 return !mem_cgroup_disabled() && !mem_cgroup_is_root(memcg) &&
6de64beb 2895 memcg_kmem_is_active(memcg);
7ae1e1d0
GC
2896}
2897
1f458cbf
GC
2898/*
2899 * This is a bit cumbersome, but it is rarely used and avoids a backpointer
2900 * in the memcg_cache_params struct.
2901 */
2902static struct kmem_cache *memcg_params_to_cache(struct memcg_cache_params *p)
2903{
2904 struct kmem_cache *cachep;
2905
2906 VM_BUG_ON(p->is_root_cache);
2907 cachep = p->root_cache;
7a67d7ab 2908 return cache_from_memcg_idx(cachep, memcg_cache_id(p->memcg));
1f458cbf
GC
2909}
2910
749c5415 2911#ifdef CONFIG_SLABINFO
2da8ca82 2912static int mem_cgroup_slabinfo_read(struct seq_file *m, void *v)
749c5415 2913{
2da8ca82 2914 struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
749c5415
GC
2915 struct memcg_cache_params *params;
2916
2917 if (!memcg_can_account_kmem(memcg))
2918 return -EIO;
2919
2920 print_slabinfo_header(m);
2921
bd673145 2922 mutex_lock(&memcg_slab_mutex);
749c5415
GC
2923 list_for_each_entry(params, &memcg->memcg_slab_caches, list)
2924 cache_show(memcg_params_to_cache(params), m);
bd673145 2925 mutex_unlock(&memcg_slab_mutex);
749c5415
GC
2926
2927 return 0;
2928}
2929#endif
2930
c67a8a68 2931static int memcg_charge_kmem(struct mem_cgroup *memcg, gfp_t gfp, u64 size)
7ae1e1d0
GC
2932{
2933 struct res_counter *fail_res;
7ae1e1d0 2934 int ret = 0;
7ae1e1d0
GC
2935
2936 ret = res_counter_charge(&memcg->kmem, size, &fail_res);
2937 if (ret)
2938 return ret;
2939
6d1fdc48
JW
2940 ret = mem_cgroup_try_charge(memcg, gfp, size >> PAGE_SHIFT,
2941 oom_gfp_allowed(gfp));
7ae1e1d0
GC
2942 if (ret == -EINTR) {
2943 /*
6d1fdc48 2944 * mem_cgroup_try_charge() chosed to bypass to root due to
7ae1e1d0
GC
2945 * OOM kill or fatal signal. Since our only options are to
2946 * either fail the allocation or charge it to this cgroup, do
2947 * it as a temporary condition. But we can't fail. From a
2948 * kmem/slab perspective, the cache has already been selected,
2949 * by mem_cgroup_kmem_get_cache(), so it is too late to change
2950 * our minds.
2951 *
2952 * This condition will only trigger if the task entered
2953 * memcg_charge_kmem in a sane state, but was OOM-killed during
6d1fdc48 2954 * mem_cgroup_try_charge() above. Tasks that were already
7ae1e1d0
GC
2955 * dying when the allocation triggers should have been already
2956 * directed to the root cgroup in memcontrol.h
2957 */
2958 res_counter_charge_nofail(&memcg->res, size, &fail_res);
2959 if (do_swap_account)
2960 res_counter_charge_nofail(&memcg->memsw, size,
2961 &fail_res);
2962 ret = 0;
2963 } else if (ret)
2964 res_counter_uncharge(&memcg->kmem, size);
2965
2966 return ret;
2967}
2968
c67a8a68 2969static void memcg_uncharge_kmem(struct mem_cgroup *memcg, u64 size)
7ae1e1d0 2970{
7ae1e1d0
GC
2971 res_counter_uncharge(&memcg->res, size);
2972 if (do_swap_account)
2973 res_counter_uncharge(&memcg->memsw, size);
7de37682
GC
2974
2975 /* Not down to 0 */
2976 if (res_counter_uncharge(&memcg->kmem, size))
2977 return;
2978
10d5ebf4
LZ
2979 /*
2980 * Releases a reference taken in kmem_cgroup_css_offline in case
2981 * this last uncharge is racing with the offlining code or it is
2982 * outliving the memcg existence.
2983 *
2984 * The memory barrier imposed by test&clear is paired with the
2985 * explicit one in memcg_kmem_mark_dead().
2986 */
7de37682 2987 if (memcg_kmem_test_and_clear_dead(memcg))
10d5ebf4 2988 css_put(&memcg->css);
7ae1e1d0
GC
2989}
2990
2633d7a0
GC
2991/*
2992 * helper for acessing a memcg's index. It will be used as an index in the
2993 * child cache array in kmem_cache, and also to derive its name. This function
2994 * will return -1 when this is not a kmem-limited memcg.
2995 */
2996int memcg_cache_id(struct mem_cgroup *memcg)
2997{
2998 return memcg ? memcg->kmemcg_id : -1;
2999}
3000
55007d84
GC
3001static size_t memcg_caches_array_size(int num_groups)
3002{
3003 ssize_t size;
3004 if (num_groups <= 0)
3005 return 0;
3006
3007 size = 2 * num_groups;
3008 if (size < MEMCG_CACHES_MIN_SIZE)
3009 size = MEMCG_CACHES_MIN_SIZE;
3010 else if (size > MEMCG_CACHES_MAX_SIZE)
3011 size = MEMCG_CACHES_MAX_SIZE;
3012
3013 return size;
3014}
3015
3016/*
3017 * We should update the current array size iff all caches updates succeed. This
3018 * can only be done from the slab side. The slab mutex needs to be held when
3019 * calling this.
3020 */
3021void memcg_update_array_size(int num)
3022{
3023 if (num > memcg_limited_groups_array_size)
3024 memcg_limited_groups_array_size = memcg_caches_array_size(num);
3025}
3026
3027int memcg_update_cache_size(struct kmem_cache *s, int num_groups)
3028{
3029 struct memcg_cache_params *cur_params = s->memcg_params;
3030
f35c3a8e 3031 VM_BUG_ON(!is_root_cache(s));
55007d84
GC
3032
3033 if (num_groups > memcg_limited_groups_array_size) {
3034 int i;
f8570263 3035 struct memcg_cache_params *new_params;
55007d84
GC
3036 ssize_t size = memcg_caches_array_size(num_groups);
3037
3038 size *= sizeof(void *);
90c7a79c 3039 size += offsetof(struct memcg_cache_params, memcg_caches);
55007d84 3040
f8570263
VD
3041 new_params = kzalloc(size, GFP_KERNEL);
3042 if (!new_params)
55007d84 3043 return -ENOMEM;
55007d84 3044
f8570263 3045 new_params->is_root_cache = true;
55007d84
GC
3046
3047 /*
3048 * There is the chance it will be bigger than
3049 * memcg_limited_groups_array_size, if we failed an allocation
3050 * in a cache, in which case all caches updated before it, will
3051 * have a bigger array.
3052 *
3053 * But if that is the case, the data after
3054 * memcg_limited_groups_array_size is certainly unused
3055 */
3056 for (i = 0; i < memcg_limited_groups_array_size; i++) {
3057 if (!cur_params->memcg_caches[i])
3058 continue;
f8570263 3059 new_params->memcg_caches[i] =
55007d84
GC
3060 cur_params->memcg_caches[i];
3061 }
3062
3063 /*
3064 * Ideally, we would wait until all caches succeed, and only
3065 * then free the old one. But this is not worth the extra
3066 * pointer per-cache we'd have to have for this.
3067 *
3068 * It is not a big deal if some caches are left with a size
3069 * bigger than the others. And all updates will reset this
3070 * anyway.
3071 */
f8570263
VD
3072 rcu_assign_pointer(s->memcg_params, new_params);
3073 if (cur_params)
3074 kfree_rcu(cur_params, rcu_head);
55007d84
GC
3075 }
3076 return 0;
3077}
3078
363a044f
VD
3079int memcg_alloc_cache_params(struct mem_cgroup *memcg, struct kmem_cache *s,
3080 struct kmem_cache *root_cache)
2633d7a0 3081{
90c7a79c 3082 size_t size;
2633d7a0
GC
3083
3084 if (!memcg_kmem_enabled())
3085 return 0;
3086
90c7a79c
AV
3087 if (!memcg) {
3088 size = offsetof(struct memcg_cache_params, memcg_caches);
55007d84 3089 size += memcg_limited_groups_array_size * sizeof(void *);
90c7a79c
AV
3090 } else
3091 size = sizeof(struct memcg_cache_params);
55007d84 3092
2633d7a0
GC
3093 s->memcg_params = kzalloc(size, GFP_KERNEL);
3094 if (!s->memcg_params)
3095 return -ENOMEM;
3096
943a451a 3097 if (memcg) {
2633d7a0 3098 s->memcg_params->memcg = memcg;
943a451a 3099 s->memcg_params->root_cache = root_cache;
051dd460 3100 css_get(&memcg->css);
4ba902b5
GC
3101 } else
3102 s->memcg_params->is_root_cache = true;
3103
2633d7a0
GC
3104 return 0;
3105}
3106
363a044f
VD
3107void memcg_free_cache_params(struct kmem_cache *s)
3108{
051dd460
VD
3109 if (!s->memcg_params)
3110 return;
3111 if (!s->memcg_params->is_root_cache)
3112 css_put(&s->memcg_params->memcg->css);
363a044f
VD
3113 kfree(s->memcg_params);
3114}
3115
776ed0f0
VD
3116static void memcg_register_cache(struct mem_cgroup *memcg,
3117 struct kmem_cache *root_cache)
2633d7a0 3118{
93f39eea
VD
3119 static char memcg_name_buf[NAME_MAX + 1]; /* protected by
3120 memcg_slab_mutex */
bd673145 3121 struct kmem_cache *cachep;
d7f25f8a
GC
3122 int id;
3123
bd673145
VD
3124 lockdep_assert_held(&memcg_slab_mutex);
3125
3126 id = memcg_cache_id(memcg);
3127
3128 /*
3129 * Since per-memcg caches are created asynchronously on first
3130 * allocation (see memcg_kmem_get_cache()), several threads can try to
3131 * create the same cache, but only one of them may succeed.
3132 */
3133 if (cache_from_memcg_idx(root_cache, id))
1aa13254
VD
3134 return;
3135
073ee1c6 3136 cgroup_name(memcg->css.cgroup, memcg_name_buf, NAME_MAX + 1);
776ed0f0 3137 cachep = memcg_create_kmem_cache(memcg, root_cache, memcg_name_buf);
2edefe11 3138 /*
bd673145
VD
3139 * If we could not create a memcg cache, do not complain, because
3140 * that's not critical at all as we can always proceed with the root
3141 * cache.
2edefe11 3142 */
bd673145
VD
3143 if (!cachep)
3144 return;
2edefe11 3145
bd673145 3146 list_add(&cachep->memcg_params->list, &memcg->memcg_slab_caches);
1aa13254 3147
d7f25f8a 3148 /*
959c8963
VD
3149 * Since readers won't lock (see cache_from_memcg_idx()), we need a
3150 * barrier here to ensure nobody will see the kmem_cache partially
3151 * initialized.
d7f25f8a 3152 */
959c8963
VD
3153 smp_wmb();
3154
bd673145
VD
3155 BUG_ON(root_cache->memcg_params->memcg_caches[id]);
3156 root_cache->memcg_params->memcg_caches[id] = cachep;
1aa13254 3157}
d7f25f8a 3158
776ed0f0 3159static void memcg_unregister_cache(struct kmem_cache *cachep)
1aa13254 3160{
bd673145 3161 struct kmem_cache *root_cache;
1aa13254
VD
3162 struct mem_cgroup *memcg;
3163 int id;
3164
bd673145 3165 lockdep_assert_held(&memcg_slab_mutex);
d7f25f8a 3166
bd673145 3167 BUG_ON(is_root_cache(cachep));
2edefe11 3168
bd673145
VD
3169 root_cache = cachep->memcg_params->root_cache;
3170 memcg = cachep->memcg_params->memcg;
96403da2 3171 id = memcg_cache_id(memcg);
d7f25f8a 3172
bd673145
VD
3173 BUG_ON(root_cache->memcg_params->memcg_caches[id] != cachep);
3174 root_cache->memcg_params->memcg_caches[id] = NULL;
d7f25f8a 3175
bd673145
VD
3176 list_del(&cachep->memcg_params->list);
3177
3178 kmem_cache_destroy(cachep);
2633d7a0
GC
3179}
3180
0e9d92f2
GC
3181/*
3182 * During the creation a new cache, we need to disable our accounting mechanism
3183 * altogether. This is true even if we are not creating, but rather just
3184 * enqueing new caches to be created.
3185 *
3186 * This is because that process will trigger allocations; some visible, like
3187 * explicit kmallocs to auxiliary data structures, name strings and internal
3188 * cache structures; some well concealed, like INIT_WORK() that can allocate
3189 * objects during debug.
3190 *
3191 * If any allocation happens during memcg_kmem_get_cache, we will recurse back
3192 * to it. This may not be a bounded recursion: since the first cache creation
3193 * failed to complete (waiting on the allocation), we'll just try to create the
3194 * cache again, failing at the same point.
3195 *
3196 * memcg_kmem_get_cache is prepared to abort after seeing a positive count of
3197 * memcg_kmem_skip_account. So we enclose anything that might allocate memory
3198 * inside the following two functions.
3199 */
3200static inline void memcg_stop_kmem_account(void)
3201{
3202 VM_BUG_ON(!current->mm);
3203 current->memcg_kmem_skip_account++;
3204}
3205
3206static inline void memcg_resume_kmem_account(void)
3207{
3208 VM_BUG_ON(!current->mm);
3209 current->memcg_kmem_skip_account--;
3210}
3211
776ed0f0 3212int __memcg_cleanup_cache_params(struct kmem_cache *s)
7cf27982
GC
3213{
3214 struct kmem_cache *c;
b8529907 3215 int i, failed = 0;
7cf27982 3216
bd673145 3217 mutex_lock(&memcg_slab_mutex);
7a67d7ab
QH
3218 for_each_memcg_cache_index(i) {
3219 c = cache_from_memcg_idx(s, i);
7cf27982
GC
3220 if (!c)
3221 continue;
3222
776ed0f0 3223 memcg_unregister_cache(c);
b8529907
VD
3224
3225 if (cache_from_memcg_idx(s, i))
3226 failed++;
7cf27982 3227 }
bd673145 3228 mutex_unlock(&memcg_slab_mutex);
b8529907 3229 return failed;
7cf27982
GC
3230}
3231
776ed0f0 3232static void memcg_unregister_all_caches(struct mem_cgroup *memcg)
1f458cbf
GC
3233{
3234 struct kmem_cache *cachep;
bd673145 3235 struct memcg_cache_params *params, *tmp;
1f458cbf
GC
3236
3237 if (!memcg_kmem_is_active(memcg))
3238 return;
3239
bd673145
VD
3240 mutex_lock(&memcg_slab_mutex);
3241 list_for_each_entry_safe(params, tmp, &memcg->memcg_slab_caches, list) {
1f458cbf 3242 cachep = memcg_params_to_cache(params);
bd673145
VD
3243 kmem_cache_shrink(cachep);
3244 if (atomic_read(&cachep->memcg_params->nr_pages) == 0)
776ed0f0 3245 memcg_unregister_cache(cachep);
1f458cbf 3246 }
bd673145 3247 mutex_unlock(&memcg_slab_mutex);
1f458cbf
GC
3248}
3249
776ed0f0 3250struct memcg_register_cache_work {
5722d094
VD
3251 struct mem_cgroup *memcg;
3252 struct kmem_cache *cachep;
3253 struct work_struct work;
3254};
3255
776ed0f0 3256static void memcg_register_cache_func(struct work_struct *w)
d7f25f8a 3257{
776ed0f0
VD
3258 struct memcg_register_cache_work *cw =
3259 container_of(w, struct memcg_register_cache_work, work);
5722d094
VD
3260 struct mem_cgroup *memcg = cw->memcg;
3261 struct kmem_cache *cachep = cw->cachep;
d7f25f8a 3262
bd673145 3263 mutex_lock(&memcg_slab_mutex);
776ed0f0 3264 memcg_register_cache(memcg, cachep);
bd673145
VD
3265 mutex_unlock(&memcg_slab_mutex);
3266
5722d094 3267 css_put(&memcg->css);
d7f25f8a
GC
3268 kfree(cw);
3269}
3270
3271/*
3272 * Enqueue the creation of a per-memcg kmem_cache.
d7f25f8a 3273 */
776ed0f0
VD
3274static void __memcg_schedule_register_cache(struct mem_cgroup *memcg,
3275 struct kmem_cache *cachep)
d7f25f8a 3276{
776ed0f0 3277 struct memcg_register_cache_work *cw;
d7f25f8a 3278
776ed0f0 3279 cw = kmalloc(sizeof(*cw), GFP_NOWAIT);
ca0dde97
LZ
3280 if (cw == NULL) {
3281 css_put(&memcg->css);
d7f25f8a
GC
3282 return;
3283 }
3284
3285 cw->memcg = memcg;
3286 cw->cachep = cachep;
3287
776ed0f0 3288 INIT_WORK(&cw->work, memcg_register_cache_func);
d7f25f8a
GC
3289 schedule_work(&cw->work);
3290}
3291
776ed0f0
VD
3292static void memcg_schedule_register_cache(struct mem_cgroup *memcg,
3293 struct kmem_cache *cachep)
0e9d92f2
GC
3294{
3295 /*
3296 * We need to stop accounting when we kmalloc, because if the
3297 * corresponding kmalloc cache is not yet created, the first allocation
776ed0f0 3298 * in __memcg_schedule_register_cache will recurse.
0e9d92f2
GC
3299 *
3300 * However, it is better to enclose the whole function. Depending on
3301 * the debugging options enabled, INIT_WORK(), for instance, can
3302 * trigger an allocation. This too, will make us recurse. Because at
3303 * this point we can't allow ourselves back into memcg_kmem_get_cache,
3304 * the safest choice is to do it like this, wrapping the whole function.
3305 */
3306 memcg_stop_kmem_account();
776ed0f0 3307 __memcg_schedule_register_cache(memcg, cachep);
0e9d92f2
GC
3308 memcg_resume_kmem_account();
3309}
c67a8a68
VD
3310
3311int __memcg_charge_slab(struct kmem_cache *cachep, gfp_t gfp, int order)
3312{
3313 int res;
3314
3315 res = memcg_charge_kmem(cachep->memcg_params->memcg, gfp,
3316 PAGE_SIZE << order);
3317 if (!res)
3318 atomic_add(1 << order, &cachep->memcg_params->nr_pages);
3319 return res;
3320}
3321
3322void __memcg_uncharge_slab(struct kmem_cache *cachep, int order)
3323{
3324 memcg_uncharge_kmem(cachep->memcg_params->memcg, PAGE_SIZE << order);
3325 atomic_sub(1 << order, &cachep->memcg_params->nr_pages);
3326}
3327
d7f25f8a
GC
3328/*
3329 * Return the kmem_cache we're supposed to use for a slab allocation.
3330 * We try to use the current memcg's version of the cache.
3331 *
3332 * If the cache does not exist yet, if we are the first user of it,
3333 * we either create it immediately, if possible, or create it asynchronously
3334 * in a workqueue.
3335 * In the latter case, we will let the current allocation go through with
3336 * the original cache.
3337 *
3338 * Can't be called in interrupt context or from kernel threads.
3339 * This function needs to be called with rcu_read_lock() held.
3340 */
3341struct kmem_cache *__memcg_kmem_get_cache(struct kmem_cache *cachep,
3342 gfp_t gfp)
3343{
3344 struct mem_cgroup *memcg;
959c8963 3345 struct kmem_cache *memcg_cachep;
d7f25f8a
GC
3346
3347 VM_BUG_ON(!cachep->memcg_params);
3348 VM_BUG_ON(!cachep->memcg_params->is_root_cache);
3349
0e9d92f2
GC
3350 if (!current->mm || current->memcg_kmem_skip_account)
3351 return cachep;
3352
d7f25f8a
GC
3353 rcu_read_lock();
3354 memcg = mem_cgroup_from_task(rcu_dereference(current->mm->owner));
d7f25f8a
GC
3355
3356 if (!memcg_can_account_kmem(memcg))
ca0dde97 3357 goto out;
d7f25f8a 3358
959c8963
VD
3359 memcg_cachep = cache_from_memcg_idx(cachep, memcg_cache_id(memcg));
3360 if (likely(memcg_cachep)) {
3361 cachep = memcg_cachep;
ca0dde97 3362 goto out;
d7f25f8a
GC
3363 }
3364
ca0dde97 3365 /* The corresponding put will be done in the workqueue. */
ec903c0c 3366 if (!css_tryget_online(&memcg->css))
ca0dde97
LZ
3367 goto out;
3368 rcu_read_unlock();
3369
3370 /*
3371 * If we are in a safe context (can wait, and not in interrupt
3372 * context), we could be be predictable and return right away.
3373 * This would guarantee that the allocation being performed
3374 * already belongs in the new cache.
3375 *
3376 * However, there are some clashes that can arrive from locking.
3377 * For instance, because we acquire the slab_mutex while doing
776ed0f0
VD
3378 * memcg_create_kmem_cache, this means no further allocation
3379 * could happen with the slab_mutex held. So it's better to
3380 * defer everything.
ca0dde97 3381 */
776ed0f0 3382 memcg_schedule_register_cache(memcg, cachep);
ca0dde97
LZ
3383 return cachep;
3384out:
3385 rcu_read_unlock();
3386 return cachep;
d7f25f8a 3387}
d7f25f8a 3388
7ae1e1d0
GC
3389/*
3390 * We need to verify if the allocation against current->mm->owner's memcg is
3391 * possible for the given order. But the page is not allocated yet, so we'll
3392 * need a further commit step to do the final arrangements.
3393 *
3394 * It is possible for the task to switch cgroups in this mean time, so at
3395 * commit time, we can't rely on task conversion any longer. We'll then use
3396 * the handle argument to return to the caller which cgroup we should commit
3397 * against. We could also return the memcg directly and avoid the pointer
3398 * passing, but a boolean return value gives better semantics considering
3399 * the compiled-out case as well.
3400 *
3401 * Returning true means the allocation is possible.
3402 */
3403bool
3404__memcg_kmem_newpage_charge(gfp_t gfp, struct mem_cgroup **_memcg, int order)
3405{
3406 struct mem_cgroup *memcg;
3407 int ret;
3408
3409 *_memcg = NULL;
6d42c232
GC
3410
3411 /*
3412 * Disabling accounting is only relevant for some specific memcg
3413 * internal allocations. Therefore we would initially not have such
52383431
VD
3414 * check here, since direct calls to the page allocator that are
3415 * accounted to kmemcg (alloc_kmem_pages and friends) only happen
3416 * outside memcg core. We are mostly concerned with cache allocations,
3417 * and by having this test at memcg_kmem_get_cache, we are already able
3418 * to relay the allocation to the root cache and bypass the memcg cache
3419 * altogether.
6d42c232
GC
3420 *
3421 * There is one exception, though: the SLUB allocator does not create
3422 * large order caches, but rather service large kmallocs directly from
3423 * the page allocator. Therefore, the following sequence when backed by
3424 * the SLUB allocator:
3425 *
f894ffa8
AM
3426 * memcg_stop_kmem_account();
3427 * kmalloc(<large_number>)
3428 * memcg_resume_kmem_account();
6d42c232
GC
3429 *
3430 * would effectively ignore the fact that we should skip accounting,
3431 * since it will drive us directly to this function without passing
3432 * through the cache selector memcg_kmem_get_cache. Such large
3433 * allocations are extremely rare but can happen, for instance, for the
3434 * cache arrays. We bring this test here.
3435 */
3436 if (!current->mm || current->memcg_kmem_skip_account)
3437 return true;
3438
df381975 3439 memcg = get_mem_cgroup_from_mm(current->mm);
7ae1e1d0
GC
3440
3441 if (!memcg_can_account_kmem(memcg)) {
3442 css_put(&memcg->css);
3443 return true;
3444 }
3445
7ae1e1d0
GC
3446 ret = memcg_charge_kmem(memcg, gfp, PAGE_SIZE << order);
3447 if (!ret)
3448 *_memcg = memcg;
7ae1e1d0
GC
3449
3450 css_put(&memcg->css);
3451 return (ret == 0);
3452}
3453
3454void __memcg_kmem_commit_charge(struct page *page, struct mem_cgroup *memcg,
3455 int order)
3456{
3457 struct page_cgroup *pc;
3458
3459 VM_BUG_ON(mem_cgroup_is_root(memcg));
3460
3461 /* The page allocation failed. Revert */
3462 if (!page) {
3463 memcg_uncharge_kmem(memcg, PAGE_SIZE << order);
7ae1e1d0
GC
3464 return;
3465 }
3466
3467 pc = lookup_page_cgroup(page);
3468 lock_page_cgroup(pc);
3469 pc->mem_cgroup = memcg;
3470 SetPageCgroupUsed(pc);
3471 unlock_page_cgroup(pc);
3472}
3473
3474void __memcg_kmem_uncharge_pages(struct page *page, int order)
3475{
3476 struct mem_cgroup *memcg = NULL;
3477 struct page_cgroup *pc;
3478
3479
3480 pc = lookup_page_cgroup(page);
3481 /*
3482 * Fast unlocked return. Theoretically might have changed, have to
3483 * check again after locking.
3484 */
3485 if (!PageCgroupUsed(pc))
3486 return;
3487
3488 lock_page_cgroup(pc);
3489 if (PageCgroupUsed(pc)) {
3490 memcg = pc->mem_cgroup;
3491 ClearPageCgroupUsed(pc);
3492 }
3493 unlock_page_cgroup(pc);
3494
3495 /*
3496 * We trust that only if there is a memcg associated with the page, it
3497 * is a valid allocation
3498 */
3499 if (!memcg)
3500 return;
3501
309381fe 3502 VM_BUG_ON_PAGE(mem_cgroup_is_root(memcg), page);
7ae1e1d0 3503 memcg_uncharge_kmem(memcg, PAGE_SIZE << order);
7ae1e1d0 3504}
1f458cbf 3505#else
776ed0f0 3506static inline void memcg_unregister_all_caches(struct mem_cgroup *memcg)
1f458cbf
GC
3507{
3508}
7ae1e1d0
GC
3509#endif /* CONFIG_MEMCG_KMEM */
3510
ca3e0214
KH
3511#ifdef CONFIG_TRANSPARENT_HUGEPAGE
3512
a0db00fc 3513#define PCGF_NOCOPY_AT_SPLIT (1 << PCG_LOCK | 1 << PCG_MIGRATION)
ca3e0214
KH
3514/*
3515 * Because tail pages are not marked as "used", set it. We're under
e94c8a9c
KH
3516 * zone->lru_lock, 'splitting on pmd' and compound_lock.
3517 * charge/uncharge will be never happen and move_account() is done under
3518 * compound_lock(), so we don't have to take care of races.
ca3e0214 3519 */
e94c8a9c 3520void mem_cgroup_split_huge_fixup(struct page *head)
ca3e0214
KH
3521{
3522 struct page_cgroup *head_pc = lookup_page_cgroup(head);
e94c8a9c 3523 struct page_cgroup *pc;
b070e65c 3524 struct mem_cgroup *memcg;
e94c8a9c 3525 int i;
ca3e0214 3526
3d37c4a9
KH
3527 if (mem_cgroup_disabled())
3528 return;
b070e65c
DR
3529
3530 memcg = head_pc->mem_cgroup;
e94c8a9c
KH
3531 for (i = 1; i < HPAGE_PMD_NR; i++) {
3532 pc = head_pc + i;
b070e65c 3533 pc->mem_cgroup = memcg;
e94c8a9c 3534 smp_wmb();/* see __commit_charge() */
e94c8a9c
KH
3535 pc->flags = head_pc->flags & ~PCGF_NOCOPY_AT_SPLIT;
3536 }
b070e65c
DR
3537 __this_cpu_sub(memcg->stat->count[MEM_CGROUP_STAT_RSS_HUGE],
3538 HPAGE_PMD_NR);
ca3e0214 3539}
12d27107 3540#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
ca3e0214 3541
f817ed48 3542/**
de3638d9 3543 * mem_cgroup_move_account - move account of the page
5564e88b 3544 * @page: the page
7ec99d62 3545 * @nr_pages: number of regular pages (>1 for huge pages)
f817ed48
KH
3546 * @pc: page_cgroup of the page.
3547 * @from: mem_cgroup which the page is moved from.
3548 * @to: mem_cgroup which the page is moved to. @from != @to.
3549 *
3550 * The caller must confirm following.
08e552c6 3551 * - page is not on LRU (isolate_page() is useful.)
7ec99d62 3552 * - compound_lock is held when nr_pages > 1
f817ed48 3553 *
2f3479b1
KH
3554 * This function doesn't do "charge" to new cgroup and doesn't do "uncharge"
3555 * from old cgroup.
f817ed48 3556 */
7ec99d62
JW
3557static int mem_cgroup_move_account(struct page *page,
3558 unsigned int nr_pages,
3559 struct page_cgroup *pc,
3560 struct mem_cgroup *from,
2f3479b1 3561 struct mem_cgroup *to)
f817ed48 3562{
de3638d9
JW
3563 unsigned long flags;
3564 int ret;
b2402857 3565 bool anon = PageAnon(page);
987eba66 3566
f817ed48 3567 VM_BUG_ON(from == to);
309381fe 3568 VM_BUG_ON_PAGE(PageLRU(page), page);
de3638d9
JW
3569 /*
3570 * The page is isolated from LRU. So, collapse function
3571 * will not handle this page. But page splitting can happen.
3572 * Do this check under compound_page_lock(). The caller should
3573 * hold it.
3574 */
3575 ret = -EBUSY;
7ec99d62 3576 if (nr_pages > 1 && !PageTransHuge(page))
de3638d9
JW
3577 goto out;
3578
3579 lock_page_cgroup(pc);
3580
3581 ret = -EINVAL;
3582 if (!PageCgroupUsed(pc) || pc->mem_cgroup != from)
3583 goto unlock;
3584
312734c0 3585 move_lock_mem_cgroup(from, &flags);
f817ed48 3586
59d1d256
JW
3587 if (!anon && page_mapped(page)) {
3588 __this_cpu_sub(from->stat->count[MEM_CGROUP_STAT_FILE_MAPPED],
3589 nr_pages);
3590 __this_cpu_add(to->stat->count[MEM_CGROUP_STAT_FILE_MAPPED],
3591 nr_pages);
3592 }
3ea67d06 3593
59d1d256
JW
3594 if (PageWriteback(page)) {
3595 __this_cpu_sub(from->stat->count[MEM_CGROUP_STAT_WRITEBACK],
3596 nr_pages);
3597 __this_cpu_add(to->stat->count[MEM_CGROUP_STAT_WRITEBACK],
3598 nr_pages);
3599 }
3ea67d06 3600
b070e65c 3601 mem_cgroup_charge_statistics(from, page, anon, -nr_pages);
d69b042f 3602
854ffa8d 3603 /* caller should have done css_get */
08e552c6 3604 pc->mem_cgroup = to;
b070e65c 3605 mem_cgroup_charge_statistics(to, page, anon, nr_pages);
312734c0 3606 move_unlock_mem_cgroup(from, &flags);
de3638d9
JW
3607 ret = 0;
3608unlock:
57f9fd7d 3609 unlock_page_cgroup(pc);
d2265e6f
KH
3610 /*
3611 * check events
3612 */
5564e88b
JW
3613 memcg_check_events(to, page);
3614 memcg_check_events(from, page);
de3638d9 3615out:
f817ed48
KH
3616 return ret;
3617}
3618
2ef37d3f
MH
3619/**
3620 * mem_cgroup_move_parent - moves page to the parent group
3621 * @page: the page to move
3622 * @pc: page_cgroup of the page
3623 * @child: page's cgroup
3624 *
3625 * move charges to its parent or the root cgroup if the group has no
3626 * parent (aka use_hierarchy==0).
3627 * Although this might fail (get_page_unless_zero, isolate_lru_page or
3628 * mem_cgroup_move_account fails) the failure is always temporary and
3629 * it signals a race with a page removal/uncharge or migration. In the
3630 * first case the page is on the way out and it will vanish from the LRU
3631 * on the next attempt and the call should be retried later.
3632 * Isolation from the LRU fails only if page has been isolated from
3633 * the LRU since we looked at it and that usually means either global
3634 * reclaim or migration going on. The page will either get back to the
3635 * LRU or vanish.
3636 * Finaly mem_cgroup_move_account fails only if the page got uncharged
3637 * (!PageCgroupUsed) or moved to a different group. The page will
3638 * disappear in the next attempt.
f817ed48 3639 */
5564e88b
JW
3640static int mem_cgroup_move_parent(struct page *page,
3641 struct page_cgroup *pc,
6068bf01 3642 struct mem_cgroup *child)
f817ed48 3643{
f817ed48 3644 struct mem_cgroup *parent;
7ec99d62 3645 unsigned int nr_pages;
4be4489f 3646 unsigned long uninitialized_var(flags);
f817ed48
KH
3647 int ret;
3648
d8423011 3649 VM_BUG_ON(mem_cgroup_is_root(child));
f817ed48 3650
57f9fd7d
DN
3651 ret = -EBUSY;
3652 if (!get_page_unless_zero(page))
3653 goto out;
3654 if (isolate_lru_page(page))
3655 goto put;
52dbb905 3656
7ec99d62 3657 nr_pages = hpage_nr_pages(page);
08e552c6 3658
cc926f78
KH
3659 parent = parent_mem_cgroup(child);
3660 /*
3661 * If no parent, move charges to root cgroup.
3662 */
3663 if (!parent)
3664 parent = root_mem_cgroup;
f817ed48 3665
2ef37d3f 3666 if (nr_pages > 1) {
309381fe 3667 VM_BUG_ON_PAGE(!PageTransHuge(page), page);
987eba66 3668 flags = compound_lock_irqsave(page);
2ef37d3f 3669 }
987eba66 3670
cc926f78 3671 ret = mem_cgroup_move_account(page, nr_pages,
2f3479b1 3672 pc, child, parent);
cc926f78
KH
3673 if (!ret)
3674 __mem_cgroup_cancel_local_charge(child, nr_pages);
8dba474f 3675
7ec99d62 3676 if (nr_pages > 1)
987eba66 3677 compound_unlock_irqrestore(page, flags);
08e552c6 3678 putback_lru_page(page);
57f9fd7d 3679put:
40d58138 3680 put_page(page);
57f9fd7d 3681out:
f817ed48
KH
3682 return ret;
3683}
3684
d715ae08 3685int mem_cgroup_charge_anon(struct page *page,
1bec6b33 3686 struct mm_struct *mm, gfp_t gfp_mask)
7a81b88c 3687{
7ec99d62 3688 unsigned int nr_pages = 1;
6d1fdc48 3689 struct mem_cgroup *memcg;
8493ae43 3690 bool oom = true;
ec168510 3691
1bec6b33
JW
3692 if (mem_cgroup_disabled())
3693 return 0;
3694
3695 VM_BUG_ON_PAGE(page_mapped(page), page);
3696 VM_BUG_ON_PAGE(page->mapping && !PageAnon(page), page);
3697 VM_BUG_ON(!mm);
3698
37c2ac78 3699 if (PageTransHuge(page)) {
7ec99d62 3700 nr_pages <<= compound_order(page);
309381fe 3701 VM_BUG_ON_PAGE(!PageTransHuge(page), page);
8493ae43
JW
3702 /*
3703 * Never OOM-kill a process for a huge page. The
3704 * fault handler will fall back to regular pages.
3705 */
3706 oom = false;
37c2ac78 3707 }
7a81b88c 3708
6d1fdc48
JW
3709 memcg = mem_cgroup_try_charge_mm(mm, gfp_mask, nr_pages, oom);
3710 if (!memcg)
3711 return -ENOMEM;
1bec6b33
JW
3712 __mem_cgroup_commit_charge(memcg, page, nr_pages,
3713 MEM_CGROUP_CHARGE_TYPE_ANON, false);
8a9f3ccd 3714 return 0;
8a9f3ccd
BS
3715}
3716
54595fe2
KH
3717/*
3718 * While swap-in, try_charge -> commit or cancel, the page is locked.
3719 * And when try_charge() successfully returns, one refcnt to memcg without
21ae2956 3720 * struct page_cgroup is acquired. This refcnt will be consumed by
54595fe2
KH
3721 * "commit()" or removed by "cancel()"
3722 */
0435a2fd
JW
3723static int __mem_cgroup_try_charge_swapin(struct mm_struct *mm,
3724 struct page *page,
3725 gfp_t mask,
3726 struct mem_cgroup **memcgp)
8c7c6e34 3727{
6d1fdc48 3728 struct mem_cgroup *memcg = NULL;
90deb788 3729 struct page_cgroup *pc;
54595fe2 3730 int ret;
8c7c6e34 3731
90deb788
JW
3732 pc = lookup_page_cgroup(page);
3733 /*
3734 * Every swap fault against a single page tries to charge the
3735 * page, bail as early as possible. shmem_unuse() encounters
3736 * already charged pages, too. The USED bit is protected by
3737 * the page lock, which serializes swap cache removal, which
3738 * in turn serializes uncharging.
3739 */
3740 if (PageCgroupUsed(pc))
6d1fdc48
JW
3741 goto out;
3742 if (do_swap_account)
3743 memcg = try_get_mem_cgroup_from_page(page);
c0ff4b85 3744 if (!memcg)
6d1fdc48
JW
3745 memcg = get_mem_cgroup_from_mm(mm);
3746 ret = mem_cgroup_try_charge(memcg, mask, 1, true);
c0ff4b85 3747 css_put(&memcg->css);
38c5d72f 3748 if (ret == -EINTR)
6d1fdc48
JW
3749 memcg = root_mem_cgroup;
3750 else if (ret)
3751 return ret;
3752out:
3753 *memcgp = memcg;
3754 return 0;
8c7c6e34
KH
3755}
3756
0435a2fd
JW
3757int mem_cgroup_try_charge_swapin(struct mm_struct *mm, struct page *page,
3758 gfp_t gfp_mask, struct mem_cgroup **memcgp)
3759{
6d1fdc48
JW
3760 if (mem_cgroup_disabled()) {
3761 *memcgp = NULL;
0435a2fd 3762 return 0;
6d1fdc48 3763 }
bdf4f4d2
JW
3764 /*
3765 * A racing thread's fault, or swapoff, may have already
3766 * updated the pte, and even removed page from swap cache: in
3767 * those cases unuse_pte()'s pte_same() test will fail; but
3768 * there's also a KSM case which does need to charge the page.
3769 */
3770 if (!PageSwapCache(page)) {
6d1fdc48 3771 struct mem_cgroup *memcg;
bdf4f4d2 3772
6d1fdc48
JW
3773 memcg = mem_cgroup_try_charge_mm(mm, gfp_mask, 1, true);
3774 if (!memcg)
3775 return -ENOMEM;
3776 *memcgp = memcg;
3777 return 0;
bdf4f4d2 3778 }
0435a2fd
JW
3779 return __mem_cgroup_try_charge_swapin(mm, page, gfp_mask, memcgp);
3780}
3781
827a03d2
JW
3782void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *memcg)
3783{
3784 if (mem_cgroup_disabled())
3785 return;
3786 if (!memcg)
3787 return;
3788 __mem_cgroup_cancel_charge(memcg, 1);
3789}
3790
83aae4c7 3791static void
72835c86 3792__mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *memcg,
83aae4c7 3793 enum charge_type ctype)
7a81b88c 3794{
f8d66542 3795 if (mem_cgroup_disabled())
7a81b88c 3796 return;
72835c86 3797 if (!memcg)
7a81b88c 3798 return;
5a6475a4 3799
ce587e65 3800 __mem_cgroup_commit_charge(memcg, page, 1, ctype, true);
8c7c6e34
KH
3801 /*
3802 * Now swap is on-memory. This means this page may be
3803 * counted both as mem and swap....double count.
03f3c433
KH
3804 * Fix it by uncharging from memsw. Basically, this SwapCache is stable
3805 * under lock_page(). But in do_swap_page()::memory.c, reuse_swap_page()
3806 * may call delete_from_swap_cache() before reach here.
8c7c6e34 3807 */
03f3c433 3808 if (do_swap_account && PageSwapCache(page)) {
8c7c6e34 3809 swp_entry_t ent = {.val = page_private(page)};
86493009 3810 mem_cgroup_uncharge_swap(ent);
8c7c6e34 3811 }
7a81b88c
KH
3812}
3813
72835c86
JW
3814void mem_cgroup_commit_charge_swapin(struct page *page,
3815 struct mem_cgroup *memcg)
83aae4c7 3816{
72835c86 3817 __mem_cgroup_commit_charge_swapin(page, memcg,
41326c17 3818 MEM_CGROUP_CHARGE_TYPE_ANON);
83aae4c7
DN
3819}
3820
d715ae08 3821int mem_cgroup_charge_file(struct page *page, struct mm_struct *mm,
827a03d2 3822 gfp_t gfp_mask)
7a81b88c 3823{
827a03d2 3824 enum charge_type type = MEM_CGROUP_CHARGE_TYPE_CACHE;
6d1fdc48 3825 struct mem_cgroup *memcg;
827a03d2
JW
3826 int ret;
3827
f8d66542 3828 if (mem_cgroup_disabled())
827a03d2
JW
3829 return 0;
3830 if (PageCompound(page))
3831 return 0;
3832
6d1fdc48 3833 if (PageSwapCache(page)) { /* shmem */
0435a2fd
JW
3834 ret = __mem_cgroup_try_charge_swapin(mm, page,
3835 gfp_mask, &memcg);
6d1fdc48
JW
3836 if (ret)
3837 return ret;
3838 __mem_cgroup_commit_charge_swapin(page, memcg, type);
3839 return 0;
827a03d2 3840 }
6d1fdc48 3841
6f6acb00
MH
3842 memcg = mem_cgroup_try_charge_mm(mm, gfp_mask, 1, true);
3843 if (!memcg)
3844 return -ENOMEM;
6d1fdc48
JW
3845 __mem_cgroup_commit_charge(memcg, page, 1, type, false);
3846 return 0;
7a81b88c
KH
3847}
3848
c0ff4b85 3849static void mem_cgroup_do_uncharge(struct mem_cgroup *memcg,
7ec99d62
JW
3850 unsigned int nr_pages,
3851 const enum charge_type ctype)
569b846d
KH
3852{
3853 struct memcg_batch_info *batch = NULL;
3854 bool uncharge_memsw = true;
7ec99d62 3855
569b846d
KH
3856 /* If swapout, usage of swap doesn't decrease */
3857 if (!do_swap_account || ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT)
3858 uncharge_memsw = false;
569b846d
KH
3859
3860 batch = &current->memcg_batch;
3861 /*
3862 * In usual, we do css_get() when we remember memcg pointer.
3863 * But in this case, we keep res->usage until end of a series of
3864 * uncharges. Then, it's ok to ignore memcg's refcnt.
3865 */
3866 if (!batch->memcg)
c0ff4b85 3867 batch->memcg = memcg;
3c11ecf4
KH
3868 /*
3869 * do_batch > 0 when unmapping pages or inode invalidate/truncate.
25985edc 3870 * In those cases, all pages freed continuously can be expected to be in
3c11ecf4
KH
3871 * the same cgroup and we have chance to coalesce uncharges.
3872 * But we do uncharge one by one if this is killed by OOM(TIF_MEMDIE)
3873 * because we want to do uncharge as soon as possible.
3874 */
3875
3876 if (!batch->do_batch || test_thread_flag(TIF_MEMDIE))
3877 goto direct_uncharge;
3878
7ec99d62 3879 if (nr_pages > 1)
ec168510
AA
3880 goto direct_uncharge;
3881
569b846d
KH
3882 /*
3883 * In typical case, batch->memcg == mem. This means we can
3884 * merge a series of uncharges to an uncharge of res_counter.
3885 * If not, we uncharge res_counter ony by one.
3886 */
c0ff4b85 3887 if (batch->memcg != memcg)
569b846d
KH
3888 goto direct_uncharge;
3889 /* remember freed charge and uncharge it later */
7ffd4ca7 3890 batch->nr_pages++;
569b846d 3891 if (uncharge_memsw)
7ffd4ca7 3892 batch->memsw_nr_pages++;
569b846d
KH
3893 return;
3894direct_uncharge:
c0ff4b85 3895 res_counter_uncharge(&memcg->res, nr_pages * PAGE_SIZE);
569b846d 3896 if (uncharge_memsw)
c0ff4b85
R
3897 res_counter_uncharge(&memcg->memsw, nr_pages * PAGE_SIZE);
3898 if (unlikely(batch->memcg != memcg))
3899 memcg_oom_recover(memcg);
569b846d 3900}
7a81b88c 3901
8a9f3ccd 3902/*
69029cd5 3903 * uncharge if !page_mapped(page)
8a9f3ccd 3904 */
8c7c6e34 3905static struct mem_cgroup *
0030f535
JW
3906__mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype,
3907 bool end_migration)
8a9f3ccd 3908{
c0ff4b85 3909 struct mem_cgroup *memcg = NULL;
7ec99d62
JW
3910 unsigned int nr_pages = 1;
3911 struct page_cgroup *pc;
b2402857 3912 bool anon;
8a9f3ccd 3913
f8d66542 3914 if (mem_cgroup_disabled())
8c7c6e34 3915 return NULL;
4077960e 3916
37c2ac78 3917 if (PageTransHuge(page)) {
7ec99d62 3918 nr_pages <<= compound_order(page);
309381fe 3919 VM_BUG_ON_PAGE(!PageTransHuge(page), page);
37c2ac78 3920 }
8697d331 3921 /*
3c541e14 3922 * Check if our page_cgroup is valid
8697d331 3923 */
52d4b9ac 3924 pc = lookup_page_cgroup(page);
cfa44946 3925 if (unlikely(!PageCgroupUsed(pc)))
8c7c6e34 3926 return NULL;
b9c565d5 3927
52d4b9ac 3928 lock_page_cgroup(pc);
d13d1443 3929
c0ff4b85 3930 memcg = pc->mem_cgroup;
8c7c6e34 3931
d13d1443
KH
3932 if (!PageCgroupUsed(pc))
3933 goto unlock_out;
3934
b2402857
KH
3935 anon = PageAnon(page);
3936
d13d1443 3937 switch (ctype) {
41326c17 3938 case MEM_CGROUP_CHARGE_TYPE_ANON:
2ff76f11
KH
3939 /*
3940 * Generally PageAnon tells if it's the anon statistics to be
3941 * updated; but sometimes e.g. mem_cgroup_uncharge_page() is
3942 * used before page reached the stage of being marked PageAnon.
3943 */
b2402857
KH
3944 anon = true;
3945 /* fallthrough */
8a9478ca 3946 case MEM_CGROUP_CHARGE_TYPE_DROP:
ac39cf8c 3947 /* See mem_cgroup_prepare_migration() */
0030f535
JW
3948 if (page_mapped(page))
3949 goto unlock_out;
3950 /*
3951 * Pages under migration may not be uncharged. But
3952 * end_migration() /must/ be the one uncharging the
3953 * unused post-migration page and so it has to call
3954 * here with the migration bit still set. See the
3955 * res_counter handling below.
3956 */
3957 if (!end_migration && PageCgroupMigration(pc))
d13d1443
KH
3958 goto unlock_out;
3959 break;
3960 case MEM_CGROUP_CHARGE_TYPE_SWAPOUT:
3961 if (!PageAnon(page)) { /* Shared memory */
3962 if (page->mapping && !page_is_file_cache(page))
3963 goto unlock_out;
3964 } else if (page_mapped(page)) /* Anon */
3965 goto unlock_out;
3966 break;
3967 default:
3968 break;
52d4b9ac 3969 }
d13d1443 3970
b070e65c 3971 mem_cgroup_charge_statistics(memcg, page, anon, -nr_pages);
04046e1a 3972
52d4b9ac 3973 ClearPageCgroupUsed(pc);
544122e5
KH
3974 /*
3975 * pc->mem_cgroup is not cleared here. It will be accessed when it's
3976 * freed from LRU. This is safe because uncharged page is expected not
3977 * to be reused (freed soon). Exception is SwapCache, it's handled by
3978 * special functions.
3979 */
b9c565d5 3980
52d4b9ac 3981 unlock_page_cgroup(pc);
f75ca962 3982 /*
c0ff4b85 3983 * even after unlock, we have memcg->res.usage here and this memcg
4050377b 3984 * will never be freed, so it's safe to call css_get().
f75ca962 3985 */
c0ff4b85 3986 memcg_check_events(memcg, page);
f75ca962 3987 if (do_swap_account && ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT) {
c0ff4b85 3988 mem_cgroup_swap_statistics(memcg, true);
4050377b 3989 css_get(&memcg->css);
f75ca962 3990 }
0030f535
JW
3991 /*
3992 * Migration does not charge the res_counter for the
3993 * replacement page, so leave it alone when phasing out the
3994 * page that is unused after the migration.
3995 */
3996 if (!end_migration && !mem_cgroup_is_root(memcg))
c0ff4b85 3997 mem_cgroup_do_uncharge(memcg, nr_pages, ctype);
6d12e2d8 3998
c0ff4b85 3999 return memcg;
d13d1443
KH
4000
4001unlock_out:
4002 unlock_page_cgroup(pc);
8c7c6e34 4003 return NULL;
3c541e14
BS
4004}
4005
69029cd5
KH
4006void mem_cgroup_uncharge_page(struct page *page)
4007{
52d4b9ac
KH
4008 /* early check. */
4009 if (page_mapped(page))
4010 return;
309381fe 4011 VM_BUG_ON_PAGE(page->mapping && !PageAnon(page), page);
28ccddf7
JW
4012 /*
4013 * If the page is in swap cache, uncharge should be deferred
4014 * to the swap path, which also properly accounts swap usage
4015 * and handles memcg lifetime.
4016 *
4017 * Note that this check is not stable and reclaim may add the
4018 * page to swap cache at any time after this. However, if the
4019 * page is not in swap cache by the time page->mapcount hits
4020 * 0, there won't be any page table references to the swap
4021 * slot, and reclaim will free it and not actually write the
4022 * page to disk.
4023 */
0c59b89c
JW
4024 if (PageSwapCache(page))
4025 return;
0030f535 4026 __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_ANON, false);
69029cd5
KH
4027}
4028
4029void mem_cgroup_uncharge_cache_page(struct page *page)
4030{
309381fe
SL
4031 VM_BUG_ON_PAGE(page_mapped(page), page);
4032 VM_BUG_ON_PAGE(page->mapping, page);
0030f535 4033 __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE, false);
69029cd5
KH
4034}
4035
569b846d
KH
4036/*
4037 * Batch_start/batch_end is called in unmap_page_range/invlidate/trucate.
4038 * In that cases, pages are freed continuously and we can expect pages
4039 * are in the same memcg. All these calls itself limits the number of
4040 * pages freed at once, then uncharge_start/end() is called properly.
4041 * This may be called prural(2) times in a context,
4042 */
4043
4044void mem_cgroup_uncharge_start(void)
4045{
4046 current->memcg_batch.do_batch++;
4047 /* We can do nest. */
4048 if (current->memcg_batch.do_batch == 1) {
4049 current->memcg_batch.memcg = NULL;
7ffd4ca7
JW
4050 current->memcg_batch.nr_pages = 0;
4051 current->memcg_batch.memsw_nr_pages = 0;
569b846d
KH
4052 }
4053}
4054
4055void mem_cgroup_uncharge_end(void)
4056{
4057 struct memcg_batch_info *batch = &current->memcg_batch;
4058
4059 if (!batch->do_batch)
4060 return;
4061
4062 batch->do_batch--;
4063 if (batch->do_batch) /* If stacked, do nothing. */
4064 return;
4065
4066 if (!batch->memcg)
4067 return;
4068 /*
4069 * This "batch->memcg" is valid without any css_get/put etc...
4070 * bacause we hide charges behind us.
4071 */
7ffd4ca7
JW
4072 if (batch->nr_pages)
4073 res_counter_uncharge(&batch->memcg->res,
4074 batch->nr_pages * PAGE_SIZE);
4075 if (batch->memsw_nr_pages)
4076 res_counter_uncharge(&batch->memcg->memsw,
4077 batch->memsw_nr_pages * PAGE_SIZE);
3c11ecf4 4078 memcg_oom_recover(batch->memcg);
569b846d
KH
4079 /* forget this pointer (for sanity check) */
4080 batch->memcg = NULL;
4081}
4082
e767e056 4083#ifdef CONFIG_SWAP
8c7c6e34 4084/*
e767e056 4085 * called after __delete_from_swap_cache() and drop "page" account.
8c7c6e34
KH
4086 * memcg information is recorded to swap_cgroup of "ent"
4087 */
8a9478ca
KH
4088void
4089mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout)
8c7c6e34
KH
4090{
4091 struct mem_cgroup *memcg;
8a9478ca
KH
4092 int ctype = MEM_CGROUP_CHARGE_TYPE_SWAPOUT;
4093
4094 if (!swapout) /* this was a swap cache but the swap is unused ! */
4095 ctype = MEM_CGROUP_CHARGE_TYPE_DROP;
4096
0030f535 4097 memcg = __mem_cgroup_uncharge_common(page, ctype, false);
8c7c6e34 4098
f75ca962
KH
4099 /*
4100 * record memcg information, if swapout && memcg != NULL,
4050377b 4101 * css_get() was called in uncharge().
f75ca962
KH
4102 */
4103 if (do_swap_account && swapout && memcg)
34c00c31 4104 swap_cgroup_record(ent, mem_cgroup_id(memcg));
8c7c6e34 4105}
e767e056 4106#endif
8c7c6e34 4107
c255a458 4108#ifdef CONFIG_MEMCG_SWAP
8c7c6e34
KH
4109/*
4110 * called from swap_entry_free(). remove record in swap_cgroup and
4111 * uncharge "memsw" account.
4112 */
4113void mem_cgroup_uncharge_swap(swp_entry_t ent)
d13d1443 4114{
8c7c6e34 4115 struct mem_cgroup *memcg;
a3b2d692 4116 unsigned short id;
8c7c6e34
KH
4117
4118 if (!do_swap_account)
4119 return;
4120
a3b2d692
KH
4121 id = swap_cgroup_record(ent, 0);
4122 rcu_read_lock();
4123 memcg = mem_cgroup_lookup(id);
8c7c6e34 4124 if (memcg) {
a3b2d692 4125 /*
ec903c0c
TH
4126 * We uncharge this because swap is freed. This memcg can
4127 * be obsolete one. We avoid calling css_tryget_online().
a3b2d692 4128 */
0c3e73e8 4129 if (!mem_cgroup_is_root(memcg))
4e649152 4130 res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
0c3e73e8 4131 mem_cgroup_swap_statistics(memcg, false);
4050377b 4132 css_put(&memcg->css);
8c7c6e34 4133 }
a3b2d692 4134 rcu_read_unlock();
d13d1443 4135}
02491447
DN
4136
4137/**
4138 * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record.
4139 * @entry: swap entry to be moved
4140 * @from: mem_cgroup which the entry is moved from
4141 * @to: mem_cgroup which the entry is moved to
4142 *
4143 * It succeeds only when the swap_cgroup's record for this entry is the same
4144 * as the mem_cgroup's id of @from.
4145 *
4146 * Returns 0 on success, -EINVAL on failure.
4147 *
4148 * The caller must have charged to @to, IOW, called res_counter_charge() about
4149 * both res and memsw, and called css_get().
4150 */
4151static int mem_cgroup_move_swap_account(swp_entry_t entry,
e91cbb42 4152 struct mem_cgroup *from, struct mem_cgroup *to)
02491447
DN
4153{
4154 unsigned short old_id, new_id;
4155
34c00c31
LZ
4156 old_id = mem_cgroup_id(from);
4157 new_id = mem_cgroup_id(to);
02491447
DN
4158
4159 if (swap_cgroup_cmpxchg(entry, old_id, new_id) == old_id) {
02491447 4160 mem_cgroup_swap_statistics(from, false);
483c30b5 4161 mem_cgroup_swap_statistics(to, true);
02491447 4162 /*
483c30b5
DN
4163 * This function is only called from task migration context now.
4164 * It postpones res_counter and refcount handling till the end
4165 * of task migration(mem_cgroup_clear_mc()) for performance
4050377b
LZ
4166 * improvement. But we cannot postpone css_get(to) because if
4167 * the process that has been moved to @to does swap-in, the
4168 * refcount of @to might be decreased to 0.
4169 *
4170 * We are in attach() phase, so the cgroup is guaranteed to be
4171 * alive, so we can just call css_get().
02491447 4172 */
4050377b 4173 css_get(&to->css);
02491447
DN
4174 return 0;
4175 }
4176 return -EINVAL;
4177}
4178#else
4179static inline int mem_cgroup_move_swap_account(swp_entry_t entry,
e91cbb42 4180 struct mem_cgroup *from, struct mem_cgroup *to)
02491447
DN
4181{
4182 return -EINVAL;
4183}
8c7c6e34 4184#endif
d13d1443 4185
ae41be37 4186/*
01b1ae63
KH
4187 * Before starting migration, account PAGE_SIZE to mem_cgroup that the old
4188 * page belongs to.
ae41be37 4189 */
0030f535
JW
4190void mem_cgroup_prepare_migration(struct page *page, struct page *newpage,
4191 struct mem_cgroup **memcgp)
ae41be37 4192{
c0ff4b85 4193 struct mem_cgroup *memcg = NULL;
b32967ff 4194 unsigned int nr_pages = 1;
7ec99d62 4195 struct page_cgroup *pc;
ac39cf8c 4196 enum charge_type ctype;
8869b8f6 4197
72835c86 4198 *memcgp = NULL;
56039efa 4199
f8d66542 4200 if (mem_cgroup_disabled())
0030f535 4201 return;
4077960e 4202
b32967ff
MG
4203 if (PageTransHuge(page))
4204 nr_pages <<= compound_order(page);
4205
52d4b9ac
KH
4206 pc = lookup_page_cgroup(page);
4207 lock_page_cgroup(pc);
4208 if (PageCgroupUsed(pc)) {
c0ff4b85
R
4209 memcg = pc->mem_cgroup;
4210 css_get(&memcg->css);
ac39cf8c
AM
4211 /*
4212 * At migrating an anonymous page, its mapcount goes down
4213 * to 0 and uncharge() will be called. But, even if it's fully
4214 * unmapped, migration may fail and this page has to be
4215 * charged again. We set MIGRATION flag here and delay uncharge
4216 * until end_migration() is called
4217 *
4218 * Corner Case Thinking
4219 * A)
4220 * When the old page was mapped as Anon and it's unmap-and-freed
4221 * while migration was ongoing.
4222 * If unmap finds the old page, uncharge() of it will be delayed
4223 * until end_migration(). If unmap finds a new page, it's
4224 * uncharged when it make mapcount to be 1->0. If unmap code
4225 * finds swap_migration_entry, the new page will not be mapped
4226 * and end_migration() will find it(mapcount==0).
4227 *
4228 * B)
4229 * When the old page was mapped but migraion fails, the kernel
4230 * remaps it. A charge for it is kept by MIGRATION flag even
4231 * if mapcount goes down to 0. We can do remap successfully
4232 * without charging it again.
4233 *
4234 * C)
4235 * The "old" page is under lock_page() until the end of
4236 * migration, so, the old page itself will not be swapped-out.
4237 * If the new page is swapped out before end_migraton, our
4238 * hook to usual swap-out path will catch the event.
4239 */
4240 if (PageAnon(page))
4241 SetPageCgroupMigration(pc);
e8589cc1 4242 }
52d4b9ac 4243 unlock_page_cgroup(pc);
ac39cf8c
AM
4244 /*
4245 * If the page is not charged at this point,
4246 * we return here.
4247 */
c0ff4b85 4248 if (!memcg)
0030f535 4249 return;
01b1ae63 4250
72835c86 4251 *memcgp = memcg;
ac39cf8c
AM
4252 /*
4253 * We charge new page before it's used/mapped. So, even if unlock_page()
4254 * is called before end_migration, we can catch all events on this new
4255 * page. In the case new page is migrated but not remapped, new page's
4256 * mapcount will be finally 0 and we call uncharge in end_migration().
4257 */
ac39cf8c 4258 if (PageAnon(page))
41326c17 4259 ctype = MEM_CGROUP_CHARGE_TYPE_ANON;
ac39cf8c 4260 else
62ba7442 4261 ctype = MEM_CGROUP_CHARGE_TYPE_CACHE;
0030f535
JW
4262 /*
4263 * The page is committed to the memcg, but it's not actually
4264 * charged to the res_counter since we plan on replacing the
4265 * old one and only one page is going to be left afterwards.
4266 */
b32967ff 4267 __mem_cgroup_commit_charge(memcg, newpage, nr_pages, ctype, false);
ae41be37 4268}
8869b8f6 4269
69029cd5 4270/* remove redundant charge if migration failed*/
c0ff4b85 4271void mem_cgroup_end_migration(struct mem_cgroup *memcg,
50de1dd9 4272 struct page *oldpage, struct page *newpage, bool migration_ok)
ae41be37 4273{
ac39cf8c 4274 struct page *used, *unused;
01b1ae63 4275 struct page_cgroup *pc;
b2402857 4276 bool anon;
01b1ae63 4277
c0ff4b85 4278 if (!memcg)
01b1ae63 4279 return;
b25ed609 4280
50de1dd9 4281 if (!migration_ok) {
ac39cf8c
AM
4282 used = oldpage;
4283 unused = newpage;
01b1ae63 4284 } else {
ac39cf8c 4285 used = newpage;
01b1ae63
KH
4286 unused = oldpage;
4287 }
0030f535 4288 anon = PageAnon(used);
7d188958
JW
4289 __mem_cgroup_uncharge_common(unused,
4290 anon ? MEM_CGROUP_CHARGE_TYPE_ANON
4291 : MEM_CGROUP_CHARGE_TYPE_CACHE,
4292 true);
0030f535 4293 css_put(&memcg->css);
69029cd5 4294 /*
ac39cf8c
AM
4295 * We disallowed uncharge of pages under migration because mapcount
4296 * of the page goes down to zero, temporarly.
4297 * Clear the flag and check the page should be charged.
01b1ae63 4298 */
ac39cf8c
AM
4299 pc = lookup_page_cgroup(oldpage);
4300 lock_page_cgroup(pc);
4301 ClearPageCgroupMigration(pc);
4302 unlock_page_cgroup(pc);
ac39cf8c 4303
01b1ae63 4304 /*
ac39cf8c
AM
4305 * If a page is a file cache, radix-tree replacement is very atomic
4306 * and we can skip this check. When it was an Anon page, its mapcount
4307 * goes down to 0. But because we added MIGRATION flage, it's not
4308 * uncharged yet. There are several case but page->mapcount check
4309 * and USED bit check in mem_cgroup_uncharge_page() will do enough
4310 * check. (see prepare_charge() also)
69029cd5 4311 */
b2402857 4312 if (anon)
ac39cf8c 4313 mem_cgroup_uncharge_page(used);
ae41be37 4314}
78fb7466 4315
ab936cbc
KH
4316/*
4317 * At replace page cache, newpage is not under any memcg but it's on
4318 * LRU. So, this function doesn't touch res_counter but handles LRU
4319 * in correct way. Both pages are locked so we cannot race with uncharge.
4320 */
4321void mem_cgroup_replace_page_cache(struct page *oldpage,
4322 struct page *newpage)
4323{
bde05d1c 4324 struct mem_cgroup *memcg = NULL;
ab936cbc 4325 struct page_cgroup *pc;
ab936cbc 4326 enum charge_type type = MEM_CGROUP_CHARGE_TYPE_CACHE;
ab936cbc
KH
4327
4328 if (mem_cgroup_disabled())
4329 return;
4330
4331 pc = lookup_page_cgroup(oldpage);
4332 /* fix accounting on old pages */
4333 lock_page_cgroup(pc);
bde05d1c
HD
4334 if (PageCgroupUsed(pc)) {
4335 memcg = pc->mem_cgroup;
b070e65c 4336 mem_cgroup_charge_statistics(memcg, oldpage, false, -1);
bde05d1c
HD
4337 ClearPageCgroupUsed(pc);
4338 }
ab936cbc
KH
4339 unlock_page_cgroup(pc);
4340
bde05d1c
HD
4341 /*
4342 * When called from shmem_replace_page(), in some cases the
4343 * oldpage has already been charged, and in some cases not.
4344 */
4345 if (!memcg)
4346 return;
ab936cbc
KH
4347 /*
4348 * Even if newpage->mapping was NULL before starting replacement,
4349 * the newpage may be on LRU(or pagevec for LRU) already. We lock
4350 * LRU while we overwrite pc->mem_cgroup.
4351 */
ce587e65 4352 __mem_cgroup_commit_charge(memcg, newpage, 1, type, true);
ab936cbc
KH
4353}
4354
f212ad7c
DN
4355#ifdef CONFIG_DEBUG_VM
4356static struct page_cgroup *lookup_page_cgroup_used(struct page *page)
4357{
4358 struct page_cgroup *pc;
4359
4360 pc = lookup_page_cgroup(page);
cfa44946
JW
4361 /*
4362 * Can be NULL while feeding pages into the page allocator for
4363 * the first time, i.e. during boot or memory hotplug;
4364 * or when mem_cgroup_disabled().
4365 */
f212ad7c
DN
4366 if (likely(pc) && PageCgroupUsed(pc))
4367 return pc;
4368 return NULL;
4369}
4370
4371bool mem_cgroup_bad_page_check(struct page *page)
4372{
4373 if (mem_cgroup_disabled())
4374 return false;
4375
4376 return lookup_page_cgroup_used(page) != NULL;
4377}
4378
4379void mem_cgroup_print_bad_page(struct page *page)
4380{
4381 struct page_cgroup *pc;
4382
4383 pc = lookup_page_cgroup_used(page);
4384 if (pc) {
d045197f
AM
4385 pr_alert("pc:%p pc->flags:%lx pc->mem_cgroup:%p\n",
4386 pc, pc->flags, pc->mem_cgroup);
f212ad7c
DN
4387 }
4388}
4389#endif
4390
d38d2a75 4391static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
8c7c6e34 4392 unsigned long long val)
628f4235 4393{
81d39c20 4394 int retry_count;
3c11ecf4 4395 u64 memswlimit, memlimit;
628f4235 4396 int ret = 0;
81d39c20
KH
4397 int children = mem_cgroup_count_children(memcg);
4398 u64 curusage, oldusage;
3c11ecf4 4399 int enlarge;
81d39c20
KH
4400
4401 /*
4402 * For keeping hierarchical_reclaim simple, how long we should retry
4403 * is depends on callers. We set our retry-count to be function
4404 * of # of children which we should visit in this loop.
4405 */
4406 retry_count = MEM_CGROUP_RECLAIM_RETRIES * children;
4407
4408 oldusage = res_counter_read_u64(&memcg->res, RES_USAGE);
628f4235 4409
3c11ecf4 4410 enlarge = 0;
8c7c6e34 4411 while (retry_count) {
628f4235
KH
4412 if (signal_pending(current)) {
4413 ret = -EINTR;
4414 break;
4415 }
8c7c6e34
KH
4416 /*
4417 * Rather than hide all in some function, I do this in
4418 * open coded manner. You see what this really does.
aaad153e 4419 * We have to guarantee memcg->res.limit <= memcg->memsw.limit.
8c7c6e34
KH
4420 */
4421 mutex_lock(&set_limit_mutex);
4422 memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
4423 if (memswlimit < val) {
4424 ret = -EINVAL;
4425 mutex_unlock(&set_limit_mutex);
628f4235
KH
4426 break;
4427 }
3c11ecf4
KH
4428
4429 memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT);
4430 if (memlimit < val)
4431 enlarge = 1;
4432
8c7c6e34 4433 ret = res_counter_set_limit(&memcg->res, val);
22a668d7
KH
4434 if (!ret) {
4435 if (memswlimit == val)
4436 memcg->memsw_is_minimum = true;
4437 else
4438 memcg->memsw_is_minimum = false;
4439 }
8c7c6e34
KH
4440 mutex_unlock(&set_limit_mutex);
4441
4442 if (!ret)
4443 break;
4444
5660048c
JW
4445 mem_cgroup_reclaim(memcg, GFP_KERNEL,
4446 MEM_CGROUP_RECLAIM_SHRINK);
81d39c20
KH
4447 curusage = res_counter_read_u64(&memcg->res, RES_USAGE);
4448 /* Usage is reduced ? */
f894ffa8 4449 if (curusage >= oldusage)
81d39c20
KH
4450 retry_count--;
4451 else
4452 oldusage = curusage;
8c7c6e34 4453 }
3c11ecf4
KH
4454 if (!ret && enlarge)
4455 memcg_oom_recover(memcg);
14797e23 4456
8c7c6e34
KH
4457 return ret;
4458}
4459
338c8431
LZ
4460static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
4461 unsigned long long val)
8c7c6e34 4462{
81d39c20 4463 int retry_count;
3c11ecf4 4464 u64 memlimit, memswlimit, oldusage, curusage;
81d39c20
KH
4465 int children = mem_cgroup_count_children(memcg);
4466 int ret = -EBUSY;
3c11ecf4 4467 int enlarge = 0;
8c7c6e34 4468
81d39c20 4469 /* see mem_cgroup_resize_res_limit */
f894ffa8 4470 retry_count = children * MEM_CGROUP_RECLAIM_RETRIES;
81d39c20 4471 oldusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
8c7c6e34
KH
4472 while (retry_count) {
4473 if (signal_pending(current)) {
4474 ret = -EINTR;
4475 break;
4476 }
4477 /*
4478 * Rather than hide all in some function, I do this in
4479 * open coded manner. You see what this really does.
aaad153e 4480 * We have to guarantee memcg->res.limit <= memcg->memsw.limit.
8c7c6e34
KH
4481 */
4482 mutex_lock(&set_limit_mutex);
4483 memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT);
4484 if (memlimit > val) {
4485 ret = -EINVAL;
4486 mutex_unlock(&set_limit_mutex);
4487 break;
4488 }
3c11ecf4
KH
4489 memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
4490 if (memswlimit < val)
4491 enlarge = 1;
8c7c6e34 4492 ret = res_counter_set_limit(&memcg->memsw, val);
22a668d7
KH
4493 if (!ret) {
4494 if (memlimit == val)
4495 memcg->memsw_is_minimum = true;
4496 else
4497 memcg->memsw_is_minimum = false;
4498 }
8c7c6e34
KH
4499 mutex_unlock(&set_limit_mutex);
4500
4501 if (!ret)
4502 break;
4503
5660048c
JW
4504 mem_cgroup_reclaim(memcg, GFP_KERNEL,
4505 MEM_CGROUP_RECLAIM_NOSWAP |
4506 MEM_CGROUP_RECLAIM_SHRINK);
8c7c6e34 4507 curusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
81d39c20 4508 /* Usage is reduced ? */
8c7c6e34 4509 if (curusage >= oldusage)
628f4235 4510 retry_count--;
81d39c20
KH
4511 else
4512 oldusage = curusage;
628f4235 4513 }
3c11ecf4
KH
4514 if (!ret && enlarge)
4515 memcg_oom_recover(memcg);
628f4235
KH
4516 return ret;
4517}
4518
0608f43d
AM
4519unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
4520 gfp_t gfp_mask,
4521 unsigned long *total_scanned)
4522{
4523 unsigned long nr_reclaimed = 0;
4524 struct mem_cgroup_per_zone *mz, *next_mz = NULL;
4525 unsigned long reclaimed;
4526 int loop = 0;
4527 struct mem_cgroup_tree_per_zone *mctz;
4528 unsigned long long excess;
4529 unsigned long nr_scanned;
4530
4531 if (order > 0)
4532 return 0;
4533
4534 mctz = soft_limit_tree_node_zone(zone_to_nid(zone), zone_idx(zone));
4535 /*
4536 * This loop can run a while, specially if mem_cgroup's continuously
4537 * keep exceeding their soft limit and putting the system under
4538 * pressure
4539 */
4540 do {
4541 if (next_mz)
4542 mz = next_mz;
4543 else
4544 mz = mem_cgroup_largest_soft_limit_node(mctz);
4545 if (!mz)
4546 break;
4547
4548 nr_scanned = 0;
4549 reclaimed = mem_cgroup_soft_reclaim(mz->memcg, zone,
4550 gfp_mask, &nr_scanned);
4551 nr_reclaimed += reclaimed;
4552 *total_scanned += nr_scanned;
4553 spin_lock(&mctz->lock);
4554
4555 /*
4556 * If we failed to reclaim anything from this memory cgroup
4557 * it is time to move on to the next cgroup
4558 */
4559 next_mz = NULL;
4560 if (!reclaimed) {
4561 do {
4562 /*
4563 * Loop until we find yet another one.
4564 *
4565 * By the time we get the soft_limit lock
4566 * again, someone might have aded the
4567 * group back on the RB tree. Iterate to
4568 * make sure we get a different mem.
4569 * mem_cgroup_largest_soft_limit_node returns
4570 * NULL if no other cgroup is present on
4571 * the tree
4572 */
4573 next_mz =
4574 __mem_cgroup_largest_soft_limit_node(mctz);
4575 if (next_mz == mz)
4576 css_put(&next_mz->memcg->css);
4577 else /* next_mz == NULL or other memcg */
4578 break;
4579 } while (1);
4580 }
cf2c8127 4581 __mem_cgroup_remove_exceeded(mz, mctz);
0608f43d
AM
4582 excess = res_counter_soft_limit_excess(&mz->memcg->res);
4583 /*
4584 * One school of thought says that we should not add
4585 * back the node to the tree if reclaim returns 0.
4586 * But our reclaim could return 0, simply because due
4587 * to priority we are exposing a smaller subset of
4588 * memory to reclaim from. Consider this as a longer
4589 * term TODO.
4590 */
4591 /* If excess == 0, no tree ops */
cf2c8127 4592 __mem_cgroup_insert_exceeded(mz, mctz, excess);
0608f43d
AM
4593 spin_unlock(&mctz->lock);
4594 css_put(&mz->memcg->css);
4595 loop++;
4596 /*
4597 * Could not reclaim anything and there are no more
4598 * mem cgroups to try or we seem to be looping without
4599 * reclaiming anything.
4600 */
4601 if (!nr_reclaimed &&
4602 (next_mz == NULL ||
4603 loop > MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS))
4604 break;
4605 } while (!nr_reclaimed);
4606 if (next_mz)
4607 css_put(&next_mz->memcg->css);
4608 return nr_reclaimed;
4609}
4610
2ef37d3f
MH
4611/**
4612 * mem_cgroup_force_empty_list - clears LRU of a group
4613 * @memcg: group to clear
4614 * @node: NUMA node
4615 * @zid: zone id
4616 * @lru: lru to to clear
4617 *
3c935d18 4618 * Traverse a specified page_cgroup list and try to drop them all. This doesn't
2ef37d3f
MH
4619 * reclaim the pages page themselves - pages are moved to the parent (or root)
4620 * group.
cc847582 4621 */
2ef37d3f 4622static void mem_cgroup_force_empty_list(struct mem_cgroup *memcg,
08e552c6 4623 int node, int zid, enum lru_list lru)
cc847582 4624{
bea8c150 4625 struct lruvec *lruvec;
2ef37d3f 4626 unsigned long flags;
072c56c1 4627 struct list_head *list;
925b7673
JW
4628 struct page *busy;
4629 struct zone *zone;
072c56c1 4630
08e552c6 4631 zone = &NODE_DATA(node)->node_zones[zid];
bea8c150
HD
4632 lruvec = mem_cgroup_zone_lruvec(zone, memcg);
4633 list = &lruvec->lists[lru];
cc847582 4634
f817ed48 4635 busy = NULL;
2ef37d3f 4636 do {
925b7673 4637 struct page_cgroup *pc;
5564e88b
JW
4638 struct page *page;
4639
08e552c6 4640 spin_lock_irqsave(&zone->lru_lock, flags);
f817ed48 4641 if (list_empty(list)) {
08e552c6 4642 spin_unlock_irqrestore(&zone->lru_lock, flags);
52d4b9ac 4643 break;
f817ed48 4644 }
925b7673
JW
4645 page = list_entry(list->prev, struct page, lru);
4646 if (busy == page) {
4647 list_move(&page->lru, list);
648bcc77 4648 busy = NULL;
08e552c6 4649 spin_unlock_irqrestore(&zone->lru_lock, flags);
f817ed48
KH
4650 continue;
4651 }
08e552c6 4652 spin_unlock_irqrestore(&zone->lru_lock, flags);
f817ed48 4653
925b7673 4654 pc = lookup_page_cgroup(page);
5564e88b 4655
3c935d18 4656 if (mem_cgroup_move_parent(page, pc, memcg)) {
f817ed48 4657 /* found lock contention or "pc" is obsolete. */
925b7673 4658 busy = page;
f817ed48
KH
4659 } else
4660 busy = NULL;
2a7a0e0f 4661 cond_resched();
2ef37d3f 4662 } while (!list_empty(list));
cc847582
KH
4663}
4664
4665/*
c26251f9
MH
4666 * make mem_cgroup's charge to be 0 if there is no task by moving
4667 * all the charges and pages to the parent.
cc847582 4668 * This enables deleting this mem_cgroup.
c26251f9
MH
4669 *
4670 * Caller is responsible for holding css reference on the memcg.
cc847582 4671 */
ab5196c2 4672static void mem_cgroup_reparent_charges(struct mem_cgroup *memcg)
cc847582 4673{
c26251f9 4674 int node, zid;
bea207c8 4675 u64 usage;
f817ed48 4676
fce66477 4677 do {
52d4b9ac
KH
4678 /* This is for making all *used* pages to be on LRU. */
4679 lru_add_drain_all();
c0ff4b85 4680 drain_all_stock_sync(memcg);
c0ff4b85 4681 mem_cgroup_start_move(memcg);
31aaea4a 4682 for_each_node_state(node, N_MEMORY) {
2ef37d3f 4683 for (zid = 0; zid < MAX_NR_ZONES; zid++) {
f156ab93
HD
4684 enum lru_list lru;
4685 for_each_lru(lru) {
2ef37d3f 4686 mem_cgroup_force_empty_list(memcg,
f156ab93 4687 node, zid, lru);
f817ed48 4688 }
1ecaab2b 4689 }
f817ed48 4690 }
c0ff4b85
R
4691 mem_cgroup_end_move(memcg);
4692 memcg_oom_recover(memcg);
52d4b9ac 4693 cond_resched();
f817ed48 4694
2ef37d3f 4695 /*
bea207c8
GC
4696 * Kernel memory may not necessarily be trackable to a specific
4697 * process. So they are not migrated, and therefore we can't
4698 * expect their value to drop to 0 here.
4699 * Having res filled up with kmem only is enough.
4700 *
2ef37d3f
MH
4701 * This is a safety check because mem_cgroup_force_empty_list
4702 * could have raced with mem_cgroup_replace_page_cache callers
4703 * so the lru seemed empty but the page could have been added
4704 * right after the check. RES_USAGE should be safe as we always
4705 * charge before adding to the LRU.
4706 */
bea207c8
GC
4707 usage = res_counter_read_u64(&memcg->res, RES_USAGE) -
4708 res_counter_read_u64(&memcg->kmem, RES_USAGE);
4709 } while (usage > 0);
c26251f9
MH
4710}
4711
ea280e7b
TH
4712/*
4713 * Test whether @memcg has children, dead or alive. Note that this
4714 * function doesn't care whether @memcg has use_hierarchy enabled and
4715 * returns %true if there are child csses according to the cgroup
4716 * hierarchy. Testing use_hierarchy is the caller's responsiblity.
4717 */
b5f99b53
GC
4718static inline bool memcg_has_children(struct mem_cgroup *memcg)
4719{
ea280e7b
TH
4720 bool ret;
4721
696ac172 4722 /*
ea280e7b
TH
4723 * The lock does not prevent addition or deletion of children, but
4724 * it prevents a new child from being initialized based on this
4725 * parent in css_online(), so it's enough to decide whether
4726 * hierarchically inherited attributes can still be changed or not.
696ac172 4727 */
ea280e7b
TH
4728 lockdep_assert_held(&memcg_create_mutex);
4729
4730 rcu_read_lock();
4731 ret = css_next_child(NULL, &memcg->css);
4732 rcu_read_unlock();
4733 return ret;
b5f99b53
GC
4734}
4735
c26251f9
MH
4736/*
4737 * Reclaims as many pages from the given memcg as possible and moves
4738 * the rest to the parent.
4739 *
4740 * Caller is responsible for holding css reference for memcg.
4741 */
4742static int mem_cgroup_force_empty(struct mem_cgroup *memcg)
4743{
4744 int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
c26251f9 4745
c1e862c1
KH
4746 /* we call try-to-free pages for make this cgroup empty */
4747 lru_add_drain_all();
f817ed48 4748 /* try to free all pages in this cgroup */
569530fb 4749 while (nr_retries && res_counter_read_u64(&memcg->res, RES_USAGE) > 0) {
f817ed48 4750 int progress;
c1e862c1 4751
c26251f9
MH
4752 if (signal_pending(current))
4753 return -EINTR;
4754
c0ff4b85 4755 progress = try_to_free_mem_cgroup_pages(memcg, GFP_KERNEL,
185efc0f 4756 false);
c1e862c1 4757 if (!progress) {
f817ed48 4758 nr_retries--;
c1e862c1 4759 /* maybe some writeback is necessary */
8aa7e847 4760 congestion_wait(BLK_RW_ASYNC, HZ/10);
c1e862c1 4761 }
f817ed48
KH
4762
4763 }
ab5196c2
MH
4764
4765 return 0;
cc847582
KH
4766}
4767
6770c64e
TH
4768static ssize_t mem_cgroup_force_empty_write(struct kernfs_open_file *of,
4769 char *buf, size_t nbytes,
4770 loff_t off)
c1e862c1 4771{
6770c64e 4772 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
c26251f9 4773
d8423011
MH
4774 if (mem_cgroup_is_root(memcg))
4775 return -EINVAL;
6770c64e 4776 return mem_cgroup_force_empty(memcg) ?: nbytes;
c1e862c1
KH
4777}
4778
182446d0
TH
4779static u64 mem_cgroup_hierarchy_read(struct cgroup_subsys_state *css,
4780 struct cftype *cft)
18f59ea7 4781{
182446d0 4782 return mem_cgroup_from_css(css)->use_hierarchy;
18f59ea7
BS
4783}
4784
182446d0
TH
4785static int mem_cgroup_hierarchy_write(struct cgroup_subsys_state *css,
4786 struct cftype *cft, u64 val)
18f59ea7
BS
4787{
4788 int retval = 0;
182446d0 4789 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5c9d535b 4790 struct mem_cgroup *parent_memcg = mem_cgroup_from_css(memcg->css.parent);
18f59ea7 4791
0999821b 4792 mutex_lock(&memcg_create_mutex);
567fb435
GC
4793
4794 if (memcg->use_hierarchy == val)
4795 goto out;
4796
18f59ea7 4797 /*
af901ca1 4798 * If parent's use_hierarchy is set, we can't make any modifications
18f59ea7
BS
4799 * in the child subtrees. If it is unset, then the change can
4800 * occur, provided the current cgroup has no children.
4801 *
4802 * For the root cgroup, parent_mem is NULL, we allow value to be
4803 * set if there are no children.
4804 */
c0ff4b85 4805 if ((!parent_memcg || !parent_memcg->use_hierarchy) &&
18f59ea7 4806 (val == 1 || val == 0)) {
ea280e7b 4807 if (!memcg_has_children(memcg))
c0ff4b85 4808 memcg->use_hierarchy = val;
18f59ea7
BS
4809 else
4810 retval = -EBUSY;
4811 } else
4812 retval = -EINVAL;
567fb435
GC
4813
4814out:
0999821b 4815 mutex_unlock(&memcg_create_mutex);
18f59ea7
BS
4816
4817 return retval;
4818}
4819
0c3e73e8 4820
c0ff4b85 4821static unsigned long mem_cgroup_recursive_stat(struct mem_cgroup *memcg,
7a159cc9 4822 enum mem_cgroup_stat_index idx)
0c3e73e8 4823{
7d74b06f 4824 struct mem_cgroup *iter;
7a159cc9 4825 long val = 0;
0c3e73e8 4826
7a159cc9 4827 /* Per-cpu values can be negative, use a signed accumulator */
c0ff4b85 4828 for_each_mem_cgroup_tree(iter, memcg)
7d74b06f
KH
4829 val += mem_cgroup_read_stat(iter, idx);
4830
4831 if (val < 0) /* race ? */
4832 val = 0;
4833 return val;
0c3e73e8
BS
4834}
4835
c0ff4b85 4836static inline u64 mem_cgroup_usage(struct mem_cgroup *memcg, bool swap)
104f3928 4837{
7d74b06f 4838 u64 val;
104f3928 4839
c0ff4b85 4840 if (!mem_cgroup_is_root(memcg)) {
104f3928 4841 if (!swap)
65c64ce8 4842 return res_counter_read_u64(&memcg->res, RES_USAGE);
104f3928 4843 else
65c64ce8 4844 return res_counter_read_u64(&memcg->memsw, RES_USAGE);
104f3928
KS
4845 }
4846
b070e65c
DR
4847 /*
4848 * Transparent hugepages are still accounted for in MEM_CGROUP_STAT_RSS
4849 * as well as in MEM_CGROUP_STAT_RSS_HUGE.
4850 */
c0ff4b85
R
4851 val = mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_CACHE);
4852 val += mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_RSS);
104f3928 4853
7d74b06f 4854 if (swap)
bff6bb83 4855 val += mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_SWAP);
104f3928
KS
4856
4857 return val << PAGE_SHIFT;
4858}
4859
791badbd
TH
4860static u64 mem_cgroup_read_u64(struct cgroup_subsys_state *css,
4861 struct cftype *cft)
8cdea7c0 4862{
182446d0 4863 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
104f3928 4864 u64 val;
791badbd 4865 int name;
86ae53e1 4866 enum res_type type;
8c7c6e34
KH
4867
4868 type = MEMFILE_TYPE(cft->private);
4869 name = MEMFILE_ATTR(cft->private);
af36f906 4870
8c7c6e34
KH
4871 switch (type) {
4872 case _MEM:
104f3928 4873 if (name == RES_USAGE)
c0ff4b85 4874 val = mem_cgroup_usage(memcg, false);
104f3928 4875 else
c0ff4b85 4876 val = res_counter_read_u64(&memcg->res, name);
8c7c6e34
KH
4877 break;
4878 case _MEMSWAP:
104f3928 4879 if (name == RES_USAGE)
c0ff4b85 4880 val = mem_cgroup_usage(memcg, true);
104f3928 4881 else
c0ff4b85 4882 val = res_counter_read_u64(&memcg->memsw, name);
8c7c6e34 4883 break;
510fc4e1
GC
4884 case _KMEM:
4885 val = res_counter_read_u64(&memcg->kmem, name);
4886 break;
8c7c6e34
KH
4887 default:
4888 BUG();
8c7c6e34 4889 }
af36f906 4890
791badbd 4891 return val;
8cdea7c0 4892}
510fc4e1 4893
510fc4e1 4894#ifdef CONFIG_MEMCG_KMEM
d6441637
VD
4895/* should be called with activate_kmem_mutex held */
4896static int __memcg_activate_kmem(struct mem_cgroup *memcg,
4897 unsigned long long limit)
4898{
4899 int err = 0;
4900 int memcg_id;
4901
4902 if (memcg_kmem_is_active(memcg))
4903 return 0;
4904
4905 /*
4906 * We are going to allocate memory for data shared by all memory
4907 * cgroups so let's stop accounting here.
4908 */
4909 memcg_stop_kmem_account();
4910
510fc4e1
GC
4911 /*
4912 * For simplicity, we won't allow this to be disabled. It also can't
4913 * be changed if the cgroup has children already, or if tasks had
4914 * already joined.
4915 *
4916 * If tasks join before we set the limit, a person looking at
4917 * kmem.usage_in_bytes will have no way to determine when it took
4918 * place, which makes the value quite meaningless.
4919 *
4920 * After it first became limited, changes in the value of the limit are
4921 * of course permitted.
510fc4e1 4922 */
0999821b 4923 mutex_lock(&memcg_create_mutex);
ea280e7b
TH
4924 if (cgroup_has_tasks(memcg->css.cgroup) ||
4925 (memcg->use_hierarchy && memcg_has_children(memcg)))
d6441637
VD
4926 err = -EBUSY;
4927 mutex_unlock(&memcg_create_mutex);
4928 if (err)
4929 goto out;
510fc4e1 4930
d6441637
VD
4931 memcg_id = ida_simple_get(&kmem_limited_groups,
4932 0, MEMCG_CACHES_MAX_SIZE, GFP_KERNEL);
4933 if (memcg_id < 0) {
4934 err = memcg_id;
4935 goto out;
4936 }
4937
4938 /*
4939 * Make sure we have enough space for this cgroup in each root cache's
4940 * memcg_params.
4941 */
bd673145 4942 mutex_lock(&memcg_slab_mutex);
d6441637 4943 err = memcg_update_all_caches(memcg_id + 1);
bd673145 4944 mutex_unlock(&memcg_slab_mutex);
d6441637
VD
4945 if (err)
4946 goto out_rmid;
4947
4948 memcg->kmemcg_id = memcg_id;
4949 INIT_LIST_HEAD(&memcg->memcg_slab_caches);
d6441637
VD
4950
4951 /*
4952 * We couldn't have accounted to this cgroup, because it hasn't got the
4953 * active bit set yet, so this should succeed.
4954 */
4955 err = res_counter_set_limit(&memcg->kmem, limit);
4956 VM_BUG_ON(err);
4957
4958 static_key_slow_inc(&memcg_kmem_enabled_key);
4959 /*
4960 * Setting the active bit after enabling static branching will
4961 * guarantee no one starts accounting before all call sites are
4962 * patched.
4963 */
4964 memcg_kmem_set_active(memcg);
510fc4e1 4965out:
d6441637
VD
4966 memcg_resume_kmem_account();
4967 return err;
4968
4969out_rmid:
4970 ida_simple_remove(&kmem_limited_groups, memcg_id);
4971 goto out;
4972}
4973
4974static int memcg_activate_kmem(struct mem_cgroup *memcg,
4975 unsigned long long limit)
4976{
4977 int ret;
4978
4979 mutex_lock(&activate_kmem_mutex);
4980 ret = __memcg_activate_kmem(memcg, limit);
4981 mutex_unlock(&activate_kmem_mutex);
4982 return ret;
4983}
4984
4985static int memcg_update_kmem_limit(struct mem_cgroup *memcg,
4986 unsigned long long val)
4987{
4988 int ret;
4989
4990 if (!memcg_kmem_is_active(memcg))
4991 ret = memcg_activate_kmem(memcg, val);
4992 else
4993 ret = res_counter_set_limit(&memcg->kmem, val);
510fc4e1
GC
4994 return ret;
4995}
4996
55007d84 4997static int memcg_propagate_kmem(struct mem_cgroup *memcg)
510fc4e1 4998{
55007d84 4999 int ret = 0;
510fc4e1 5000 struct mem_cgroup *parent = parent_mem_cgroup(memcg);
55007d84 5001
d6441637
VD
5002 if (!parent)
5003 return 0;
55007d84 5004
d6441637 5005 mutex_lock(&activate_kmem_mutex);
55007d84 5006 /*
d6441637
VD
5007 * If the parent cgroup is not kmem-active now, it cannot be activated
5008 * after this point, because it has at least one child already.
55007d84 5009 */
d6441637
VD
5010 if (memcg_kmem_is_active(parent))
5011 ret = __memcg_activate_kmem(memcg, RES_COUNTER_MAX);
5012 mutex_unlock(&activate_kmem_mutex);
55007d84 5013 return ret;
510fc4e1 5014}
d6441637
VD
5015#else
5016static int memcg_update_kmem_limit(struct mem_cgroup *memcg,
5017 unsigned long long val)
5018{
5019 return -EINVAL;
5020}
6d043990 5021#endif /* CONFIG_MEMCG_KMEM */
510fc4e1 5022
628f4235
KH
5023/*
5024 * The user of this function is...
5025 * RES_LIMIT.
5026 */
451af504
TH
5027static ssize_t mem_cgroup_write(struct kernfs_open_file *of,
5028 char *buf, size_t nbytes, loff_t off)
8cdea7c0 5029{
451af504 5030 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
86ae53e1
GC
5031 enum res_type type;
5032 int name;
628f4235
KH
5033 unsigned long long val;
5034 int ret;
5035
451af504
TH
5036 buf = strstrip(buf);
5037 type = MEMFILE_TYPE(of_cft(of)->private);
5038 name = MEMFILE_ATTR(of_cft(of)->private);
af36f906 5039
8c7c6e34 5040 switch (name) {
628f4235 5041 case RES_LIMIT:
4b3bde4c
BS
5042 if (mem_cgroup_is_root(memcg)) { /* Can't set limit on root */
5043 ret = -EINVAL;
5044 break;
5045 }
628f4235 5046 /* This function does all necessary parse...reuse it */
451af504 5047 ret = res_counter_memparse_write_strategy(buf, &val);
8c7c6e34
KH
5048 if (ret)
5049 break;
5050 if (type == _MEM)
628f4235 5051 ret = mem_cgroup_resize_limit(memcg, val);
510fc4e1 5052 else if (type == _MEMSWAP)
8c7c6e34 5053 ret = mem_cgroup_resize_memsw_limit(memcg, val);
510fc4e1 5054 else if (type == _KMEM)
d6441637 5055 ret = memcg_update_kmem_limit(memcg, val);
510fc4e1
GC
5056 else
5057 return -EINVAL;
628f4235 5058 break;
296c81d8 5059 case RES_SOFT_LIMIT:
451af504 5060 ret = res_counter_memparse_write_strategy(buf, &val);
296c81d8
BS
5061 if (ret)
5062 break;
5063 /*
5064 * For memsw, soft limits are hard to implement in terms
5065 * of semantics, for now, we support soft limits for
5066 * control without swap
5067 */
5068 if (type == _MEM)
5069 ret = res_counter_set_soft_limit(&memcg->res, val);
5070 else
5071 ret = -EINVAL;
5072 break;
628f4235
KH
5073 default:
5074 ret = -EINVAL; /* should be BUG() ? */
5075 break;
5076 }
451af504 5077 return ret ?: nbytes;
8cdea7c0
BS
5078}
5079
fee7b548
KH
5080static void memcg_get_hierarchical_limit(struct mem_cgroup *memcg,
5081 unsigned long long *mem_limit, unsigned long long *memsw_limit)
5082{
fee7b548
KH
5083 unsigned long long min_limit, min_memsw_limit, tmp;
5084
5085 min_limit = res_counter_read_u64(&memcg->res, RES_LIMIT);
5086 min_memsw_limit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
fee7b548
KH
5087 if (!memcg->use_hierarchy)
5088 goto out;
5089
5c9d535b
TH
5090 while (memcg->css.parent) {
5091 memcg = mem_cgroup_from_css(memcg->css.parent);
fee7b548
KH
5092 if (!memcg->use_hierarchy)
5093 break;
5094 tmp = res_counter_read_u64(&memcg->res, RES_LIMIT);
5095 min_limit = min(min_limit, tmp);
5096 tmp = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
5097 min_memsw_limit = min(min_memsw_limit, tmp);
5098 }
5099out:
5100 *mem_limit = min_limit;
5101 *memsw_limit = min_memsw_limit;
fee7b548
KH
5102}
5103
6770c64e
TH
5104static ssize_t mem_cgroup_reset(struct kernfs_open_file *of, char *buf,
5105 size_t nbytes, loff_t off)
c84872e1 5106{
6770c64e 5107 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
86ae53e1
GC
5108 int name;
5109 enum res_type type;
c84872e1 5110
6770c64e
TH
5111 type = MEMFILE_TYPE(of_cft(of)->private);
5112 name = MEMFILE_ATTR(of_cft(of)->private);
af36f906 5113
8c7c6e34 5114 switch (name) {
29f2a4da 5115 case RES_MAX_USAGE:
8c7c6e34 5116 if (type == _MEM)
c0ff4b85 5117 res_counter_reset_max(&memcg->res);
510fc4e1 5118 else if (type == _MEMSWAP)
c0ff4b85 5119 res_counter_reset_max(&memcg->memsw);
510fc4e1
GC
5120 else if (type == _KMEM)
5121 res_counter_reset_max(&memcg->kmem);
5122 else
5123 return -EINVAL;
29f2a4da
PE
5124 break;
5125 case RES_FAILCNT:
8c7c6e34 5126 if (type == _MEM)
c0ff4b85 5127 res_counter_reset_failcnt(&memcg->res);
510fc4e1 5128 else if (type == _MEMSWAP)
c0ff4b85 5129 res_counter_reset_failcnt(&memcg->memsw);
510fc4e1
GC
5130 else if (type == _KMEM)
5131 res_counter_reset_failcnt(&memcg->kmem);
5132 else
5133 return -EINVAL;
29f2a4da
PE
5134 break;
5135 }
f64c3f54 5136
6770c64e 5137 return nbytes;
c84872e1
PE
5138}
5139
182446d0 5140static u64 mem_cgroup_move_charge_read(struct cgroup_subsys_state *css,
7dc74be0
DN
5141 struct cftype *cft)
5142{
182446d0 5143 return mem_cgroup_from_css(css)->move_charge_at_immigrate;
7dc74be0
DN
5144}
5145
02491447 5146#ifdef CONFIG_MMU
182446d0 5147static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css,
7dc74be0
DN
5148 struct cftype *cft, u64 val)
5149{
182446d0 5150 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
7dc74be0
DN
5151
5152 if (val >= (1 << NR_MOVE_TYPE))
5153 return -EINVAL;
ee5e8472 5154
7dc74be0 5155 /*
ee5e8472
GC
5156 * No kind of locking is needed in here, because ->can_attach() will
5157 * check this value once in the beginning of the process, and then carry
5158 * on with stale data. This means that changes to this value will only
5159 * affect task migrations starting after the change.
7dc74be0 5160 */
c0ff4b85 5161 memcg->move_charge_at_immigrate = val;
7dc74be0
DN
5162 return 0;
5163}
02491447 5164#else
182446d0 5165static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css,
02491447
DN
5166 struct cftype *cft, u64 val)
5167{
5168 return -ENOSYS;
5169}
5170#endif
7dc74be0 5171
406eb0c9 5172#ifdef CONFIG_NUMA
2da8ca82 5173static int memcg_numa_stat_show(struct seq_file *m, void *v)
406eb0c9 5174{
25485de6
GT
5175 struct numa_stat {
5176 const char *name;
5177 unsigned int lru_mask;
5178 };
5179
5180 static const struct numa_stat stats[] = {
5181 { "total", LRU_ALL },
5182 { "file", LRU_ALL_FILE },
5183 { "anon", LRU_ALL_ANON },
5184 { "unevictable", BIT(LRU_UNEVICTABLE) },
5185 };
5186 const struct numa_stat *stat;
406eb0c9 5187 int nid;
25485de6 5188 unsigned long nr;
2da8ca82 5189 struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
406eb0c9 5190
25485de6
GT
5191 for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) {
5192 nr = mem_cgroup_nr_lru_pages(memcg, stat->lru_mask);
5193 seq_printf(m, "%s=%lu", stat->name, nr);
5194 for_each_node_state(nid, N_MEMORY) {
5195 nr = mem_cgroup_node_nr_lru_pages(memcg, nid,
5196 stat->lru_mask);
5197 seq_printf(m, " N%d=%lu", nid, nr);
5198 }
5199 seq_putc(m, '\n');
406eb0c9 5200 }
406eb0c9 5201
071aee13
YH
5202 for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) {
5203 struct mem_cgroup *iter;
5204
5205 nr = 0;
5206 for_each_mem_cgroup_tree(iter, memcg)
5207 nr += mem_cgroup_nr_lru_pages(iter, stat->lru_mask);
5208 seq_printf(m, "hierarchical_%s=%lu", stat->name, nr);
5209 for_each_node_state(nid, N_MEMORY) {
5210 nr = 0;
5211 for_each_mem_cgroup_tree(iter, memcg)
5212 nr += mem_cgroup_node_nr_lru_pages(
5213 iter, nid, stat->lru_mask);
5214 seq_printf(m, " N%d=%lu", nid, nr);
5215 }
5216 seq_putc(m, '\n');
406eb0c9 5217 }
406eb0c9 5218
406eb0c9
YH
5219 return 0;
5220}
5221#endif /* CONFIG_NUMA */
5222
af7c4b0e
JW
5223static inline void mem_cgroup_lru_names_not_uptodate(void)
5224{
5225 BUILD_BUG_ON(ARRAY_SIZE(mem_cgroup_lru_names) != NR_LRU_LISTS);
5226}
5227
2da8ca82 5228static int memcg_stat_show(struct seq_file *m, void *v)
d2ceb9b7 5229{
2da8ca82 5230 struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
af7c4b0e
JW
5231 struct mem_cgroup *mi;
5232 unsigned int i;
406eb0c9 5233
af7c4b0e 5234 for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
bff6bb83 5235 if (i == MEM_CGROUP_STAT_SWAP && !do_swap_account)
1dd3a273 5236 continue;
af7c4b0e
JW
5237 seq_printf(m, "%s %ld\n", mem_cgroup_stat_names[i],
5238 mem_cgroup_read_stat(memcg, i) * PAGE_SIZE);
1dd3a273 5239 }
7b854121 5240
af7c4b0e
JW
5241 for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++)
5242 seq_printf(m, "%s %lu\n", mem_cgroup_events_names[i],
5243 mem_cgroup_read_events(memcg, i));
5244
5245 for (i = 0; i < NR_LRU_LISTS; i++)
5246 seq_printf(m, "%s %lu\n", mem_cgroup_lru_names[i],
5247 mem_cgroup_nr_lru_pages(memcg, BIT(i)) * PAGE_SIZE);
5248
14067bb3 5249 /* Hierarchical information */
fee7b548
KH
5250 {
5251 unsigned long long limit, memsw_limit;
d79154bb 5252 memcg_get_hierarchical_limit(memcg, &limit, &memsw_limit);
78ccf5b5 5253 seq_printf(m, "hierarchical_memory_limit %llu\n", limit);
fee7b548 5254 if (do_swap_account)
78ccf5b5
JW
5255 seq_printf(m, "hierarchical_memsw_limit %llu\n",
5256 memsw_limit);
fee7b548 5257 }
7f016ee8 5258
af7c4b0e
JW
5259 for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
5260 long long val = 0;
5261
bff6bb83 5262 if (i == MEM_CGROUP_STAT_SWAP && !do_swap_account)
1dd3a273 5263 continue;
af7c4b0e
JW
5264 for_each_mem_cgroup_tree(mi, memcg)
5265 val += mem_cgroup_read_stat(mi, i) * PAGE_SIZE;
5266 seq_printf(m, "total_%s %lld\n", mem_cgroup_stat_names[i], val);
5267 }
5268
5269 for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++) {
5270 unsigned long long val = 0;
5271
5272 for_each_mem_cgroup_tree(mi, memcg)
5273 val += mem_cgroup_read_events(mi, i);
5274 seq_printf(m, "total_%s %llu\n",
5275 mem_cgroup_events_names[i], val);
5276 }
5277
5278 for (i = 0; i < NR_LRU_LISTS; i++) {
5279 unsigned long long val = 0;
5280
5281 for_each_mem_cgroup_tree(mi, memcg)
5282 val += mem_cgroup_nr_lru_pages(mi, BIT(i)) * PAGE_SIZE;
5283 seq_printf(m, "total_%s %llu\n", mem_cgroup_lru_names[i], val);
1dd3a273 5284 }
14067bb3 5285
7f016ee8 5286#ifdef CONFIG_DEBUG_VM
7f016ee8
KM
5287 {
5288 int nid, zid;
5289 struct mem_cgroup_per_zone *mz;
89abfab1 5290 struct zone_reclaim_stat *rstat;
7f016ee8
KM
5291 unsigned long recent_rotated[2] = {0, 0};
5292 unsigned long recent_scanned[2] = {0, 0};
5293
5294 for_each_online_node(nid)
5295 for (zid = 0; zid < MAX_NR_ZONES; zid++) {
e231875b 5296 mz = &memcg->nodeinfo[nid]->zoneinfo[zid];
89abfab1 5297 rstat = &mz->lruvec.reclaim_stat;
7f016ee8 5298
89abfab1
HD
5299 recent_rotated[0] += rstat->recent_rotated[0];
5300 recent_rotated[1] += rstat->recent_rotated[1];
5301 recent_scanned[0] += rstat->recent_scanned[0];
5302 recent_scanned[1] += rstat->recent_scanned[1];
7f016ee8 5303 }
78ccf5b5
JW
5304 seq_printf(m, "recent_rotated_anon %lu\n", recent_rotated[0]);
5305 seq_printf(m, "recent_rotated_file %lu\n", recent_rotated[1]);
5306 seq_printf(m, "recent_scanned_anon %lu\n", recent_scanned[0]);
5307 seq_printf(m, "recent_scanned_file %lu\n", recent_scanned[1]);
7f016ee8
KM
5308 }
5309#endif
5310
d2ceb9b7
KH
5311 return 0;
5312}
5313
182446d0
TH
5314static u64 mem_cgroup_swappiness_read(struct cgroup_subsys_state *css,
5315 struct cftype *cft)
a7885eb8 5316{
182446d0 5317 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
a7885eb8 5318
1f4c025b 5319 return mem_cgroup_swappiness(memcg);
a7885eb8
KM
5320}
5321
182446d0
TH
5322static int mem_cgroup_swappiness_write(struct cgroup_subsys_state *css,
5323 struct cftype *cft, u64 val)
a7885eb8 5324{
182446d0 5325 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
a7885eb8 5326
3dae7fec 5327 if (val > 100)
a7885eb8
KM
5328 return -EINVAL;
5329
14208b0e 5330 if (css->parent)
3dae7fec
JW
5331 memcg->swappiness = val;
5332 else
5333 vm_swappiness = val;
068b38c1 5334
a7885eb8
KM
5335 return 0;
5336}
5337
2e72b634
KS
5338static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap)
5339{
5340 struct mem_cgroup_threshold_ary *t;
5341 u64 usage;
5342 int i;
5343
5344 rcu_read_lock();
5345 if (!swap)
2c488db2 5346 t = rcu_dereference(memcg->thresholds.primary);
2e72b634 5347 else
2c488db2 5348 t = rcu_dereference(memcg->memsw_thresholds.primary);
2e72b634
KS
5349
5350 if (!t)
5351 goto unlock;
5352
5353 usage = mem_cgroup_usage(memcg, swap);
5354
5355 /*
748dad36 5356 * current_threshold points to threshold just below or equal to usage.
2e72b634
KS
5357 * If it's not true, a threshold was crossed after last
5358 * call of __mem_cgroup_threshold().
5359 */
5407a562 5360 i = t->current_threshold;
2e72b634
KS
5361
5362 /*
5363 * Iterate backward over array of thresholds starting from
5364 * current_threshold and check if a threshold is crossed.
5365 * If none of thresholds below usage is crossed, we read
5366 * only one element of the array here.
5367 */
5368 for (; i >= 0 && unlikely(t->entries[i].threshold > usage); i--)
5369 eventfd_signal(t->entries[i].eventfd, 1);
5370
5371 /* i = current_threshold + 1 */
5372 i++;
5373
5374 /*
5375 * Iterate forward over array of thresholds starting from
5376 * current_threshold+1 and check if a threshold is crossed.
5377 * If none of thresholds above usage is crossed, we read
5378 * only one element of the array here.
5379 */
5380 for (; i < t->size && unlikely(t->entries[i].threshold <= usage); i++)
5381 eventfd_signal(t->entries[i].eventfd, 1);
5382
5383 /* Update current_threshold */
5407a562 5384 t->current_threshold = i - 1;
2e72b634
KS
5385unlock:
5386 rcu_read_unlock();
5387}
5388
5389static void mem_cgroup_threshold(struct mem_cgroup *memcg)
5390{
ad4ca5f4
KS
5391 while (memcg) {
5392 __mem_cgroup_threshold(memcg, false);
5393 if (do_swap_account)
5394 __mem_cgroup_threshold(memcg, true);
5395
5396 memcg = parent_mem_cgroup(memcg);
5397 }
2e72b634
KS
5398}
5399
5400static int compare_thresholds(const void *a, const void *b)
5401{
5402 const struct mem_cgroup_threshold *_a = a;
5403 const struct mem_cgroup_threshold *_b = b;
5404
2bff24a3
GT
5405 if (_a->threshold > _b->threshold)
5406 return 1;
5407
5408 if (_a->threshold < _b->threshold)
5409 return -1;
5410
5411 return 0;
2e72b634
KS
5412}
5413
c0ff4b85 5414static int mem_cgroup_oom_notify_cb(struct mem_cgroup *memcg)
9490ff27
KH
5415{
5416 struct mem_cgroup_eventfd_list *ev;
5417
c0ff4b85 5418 list_for_each_entry(ev, &memcg->oom_notify, list)
9490ff27
KH
5419 eventfd_signal(ev->eventfd, 1);
5420 return 0;
5421}
5422
c0ff4b85 5423static void mem_cgroup_oom_notify(struct mem_cgroup *memcg)
9490ff27 5424{
7d74b06f
KH
5425 struct mem_cgroup *iter;
5426
c0ff4b85 5427 for_each_mem_cgroup_tree(iter, memcg)
7d74b06f 5428 mem_cgroup_oom_notify_cb(iter);
9490ff27
KH
5429}
5430
59b6f873 5431static int __mem_cgroup_usage_register_event(struct mem_cgroup *memcg,
347c4a87 5432 struct eventfd_ctx *eventfd, const char *args, enum res_type type)
2e72b634 5433{
2c488db2
KS
5434 struct mem_cgroup_thresholds *thresholds;
5435 struct mem_cgroup_threshold_ary *new;
2e72b634 5436 u64 threshold, usage;
2c488db2 5437 int i, size, ret;
2e72b634
KS
5438
5439 ret = res_counter_memparse_write_strategy(args, &threshold);
5440 if (ret)
5441 return ret;
5442
5443 mutex_lock(&memcg->thresholds_lock);
2c488db2 5444
2e72b634 5445 if (type == _MEM)
2c488db2 5446 thresholds = &memcg->thresholds;
2e72b634 5447 else if (type == _MEMSWAP)
2c488db2 5448 thresholds = &memcg->memsw_thresholds;
2e72b634
KS
5449 else
5450 BUG();
5451
5452 usage = mem_cgroup_usage(memcg, type == _MEMSWAP);
5453
5454 /* Check if a threshold crossed before adding a new one */
2c488db2 5455 if (thresholds->primary)
2e72b634
KS
5456 __mem_cgroup_threshold(memcg, type == _MEMSWAP);
5457
2c488db2 5458 size = thresholds->primary ? thresholds->primary->size + 1 : 1;
2e72b634
KS
5459
5460 /* Allocate memory for new array of thresholds */
2c488db2 5461 new = kmalloc(sizeof(*new) + size * sizeof(struct mem_cgroup_threshold),
2e72b634 5462 GFP_KERNEL);
2c488db2 5463 if (!new) {
2e72b634
KS
5464 ret = -ENOMEM;
5465 goto unlock;
5466 }
2c488db2 5467 new->size = size;
2e72b634
KS
5468
5469 /* Copy thresholds (if any) to new array */
2c488db2
KS
5470 if (thresholds->primary) {
5471 memcpy(new->entries, thresholds->primary->entries, (size - 1) *
2e72b634 5472 sizeof(struct mem_cgroup_threshold));
2c488db2
KS
5473 }
5474
2e72b634 5475 /* Add new threshold */
2c488db2
KS
5476 new->entries[size - 1].eventfd = eventfd;
5477 new->entries[size - 1].threshold = threshold;
2e72b634
KS
5478
5479 /* Sort thresholds. Registering of new threshold isn't time-critical */
2c488db2 5480 sort(new->entries, size, sizeof(struct mem_cgroup_threshold),
2e72b634
KS
5481 compare_thresholds, NULL);
5482
5483 /* Find current threshold */
2c488db2 5484 new->current_threshold = -1;
2e72b634 5485 for (i = 0; i < size; i++) {
748dad36 5486 if (new->entries[i].threshold <= usage) {
2e72b634 5487 /*
2c488db2
KS
5488 * new->current_threshold will not be used until
5489 * rcu_assign_pointer(), so it's safe to increment
2e72b634
KS
5490 * it here.
5491 */
2c488db2 5492 ++new->current_threshold;
748dad36
SZ
5493 } else
5494 break;
2e72b634
KS
5495 }
5496
2c488db2
KS
5497 /* Free old spare buffer and save old primary buffer as spare */
5498 kfree(thresholds->spare);
5499 thresholds->spare = thresholds->primary;
5500
5501 rcu_assign_pointer(thresholds->primary, new);
2e72b634 5502
907860ed 5503 /* To be sure that nobody uses thresholds */
2e72b634
KS
5504 synchronize_rcu();
5505
2e72b634
KS
5506unlock:
5507 mutex_unlock(&memcg->thresholds_lock);
5508
5509 return ret;
5510}
5511
59b6f873 5512static int mem_cgroup_usage_register_event(struct mem_cgroup *memcg,
347c4a87
TH
5513 struct eventfd_ctx *eventfd, const char *args)
5514{
59b6f873 5515 return __mem_cgroup_usage_register_event(memcg, eventfd, args, _MEM);
347c4a87
TH
5516}
5517
59b6f873 5518static int memsw_cgroup_usage_register_event(struct mem_cgroup *memcg,
347c4a87
TH
5519 struct eventfd_ctx *eventfd, const char *args)
5520{
59b6f873 5521 return __mem_cgroup_usage_register_event(memcg, eventfd, args, _MEMSWAP);
347c4a87
TH
5522}
5523
59b6f873 5524static void __mem_cgroup_usage_unregister_event(struct mem_cgroup *memcg,
347c4a87 5525 struct eventfd_ctx *eventfd, enum res_type type)
2e72b634 5526{
2c488db2
KS
5527 struct mem_cgroup_thresholds *thresholds;
5528 struct mem_cgroup_threshold_ary *new;
2e72b634 5529 u64 usage;
2c488db2 5530 int i, j, size;
2e72b634
KS
5531
5532 mutex_lock(&memcg->thresholds_lock);
5533 if (type == _MEM)
2c488db2 5534 thresholds = &memcg->thresholds;
2e72b634 5535 else if (type == _MEMSWAP)
2c488db2 5536 thresholds = &memcg->memsw_thresholds;
2e72b634
KS
5537 else
5538 BUG();
5539
371528ca
AV
5540 if (!thresholds->primary)
5541 goto unlock;
5542
2e72b634
KS
5543 usage = mem_cgroup_usage(memcg, type == _MEMSWAP);
5544
5545 /* Check if a threshold crossed before removing */
5546 __mem_cgroup_threshold(memcg, type == _MEMSWAP);
5547
5548 /* Calculate new number of threshold */
2c488db2
KS
5549 size = 0;
5550 for (i = 0; i < thresholds->primary->size; i++) {
5551 if (thresholds->primary->entries[i].eventfd != eventfd)
2e72b634
KS
5552 size++;
5553 }
5554
2c488db2 5555 new = thresholds->spare;
907860ed 5556
2e72b634
KS
5557 /* Set thresholds array to NULL if we don't have thresholds */
5558 if (!size) {
2c488db2
KS
5559 kfree(new);
5560 new = NULL;
907860ed 5561 goto swap_buffers;
2e72b634
KS
5562 }
5563
2c488db2 5564 new->size = size;
2e72b634
KS
5565
5566 /* Copy thresholds and find current threshold */
2c488db2
KS
5567 new->current_threshold = -1;
5568 for (i = 0, j = 0; i < thresholds->primary->size; i++) {
5569 if (thresholds->primary->entries[i].eventfd == eventfd)
2e72b634
KS
5570 continue;
5571
2c488db2 5572 new->entries[j] = thresholds->primary->entries[i];
748dad36 5573 if (new->entries[j].threshold <= usage) {
2e72b634 5574 /*
2c488db2 5575 * new->current_threshold will not be used
2e72b634
KS
5576 * until rcu_assign_pointer(), so it's safe to increment
5577 * it here.
5578 */
2c488db2 5579 ++new->current_threshold;
2e72b634
KS
5580 }
5581 j++;
5582 }
5583
907860ed 5584swap_buffers:
2c488db2
KS
5585 /* Swap primary and spare array */
5586 thresholds->spare = thresholds->primary;
8c757763
SZ
5587 /* If all events are unregistered, free the spare array */
5588 if (!new) {
5589 kfree(thresholds->spare);
5590 thresholds->spare = NULL;
5591 }
5592
2c488db2 5593 rcu_assign_pointer(thresholds->primary, new);
2e72b634 5594
907860ed 5595 /* To be sure that nobody uses thresholds */
2e72b634 5596 synchronize_rcu();
371528ca 5597unlock:
2e72b634 5598 mutex_unlock(&memcg->thresholds_lock);
2e72b634 5599}
c1e862c1 5600
59b6f873 5601static void mem_cgroup_usage_unregister_event(struct mem_cgroup *memcg,
347c4a87
TH
5602 struct eventfd_ctx *eventfd)
5603{
59b6f873 5604 return __mem_cgroup_usage_unregister_event(memcg, eventfd, _MEM);
347c4a87
TH
5605}
5606
59b6f873 5607static void memsw_cgroup_usage_unregister_event(struct mem_cgroup *memcg,
347c4a87
TH
5608 struct eventfd_ctx *eventfd)
5609{
59b6f873 5610 return __mem_cgroup_usage_unregister_event(memcg, eventfd, _MEMSWAP);
347c4a87
TH
5611}
5612
59b6f873 5613static int mem_cgroup_oom_register_event(struct mem_cgroup *memcg,
347c4a87 5614 struct eventfd_ctx *eventfd, const char *args)
9490ff27 5615{
9490ff27 5616 struct mem_cgroup_eventfd_list *event;
9490ff27 5617
9490ff27
KH
5618 event = kmalloc(sizeof(*event), GFP_KERNEL);
5619 if (!event)
5620 return -ENOMEM;
5621
1af8efe9 5622 spin_lock(&memcg_oom_lock);
9490ff27
KH
5623
5624 event->eventfd = eventfd;
5625 list_add(&event->list, &memcg->oom_notify);
5626
5627 /* already in OOM ? */
79dfdacc 5628 if (atomic_read(&memcg->under_oom))
9490ff27 5629 eventfd_signal(eventfd, 1);
1af8efe9 5630 spin_unlock(&memcg_oom_lock);
9490ff27
KH
5631
5632 return 0;
5633}
5634
59b6f873 5635static void mem_cgroup_oom_unregister_event(struct mem_cgroup *memcg,
347c4a87 5636 struct eventfd_ctx *eventfd)
9490ff27 5637{
9490ff27 5638 struct mem_cgroup_eventfd_list *ev, *tmp;
9490ff27 5639
1af8efe9 5640 spin_lock(&memcg_oom_lock);
9490ff27 5641
c0ff4b85 5642 list_for_each_entry_safe(ev, tmp, &memcg->oom_notify, list) {
9490ff27
KH
5643 if (ev->eventfd == eventfd) {
5644 list_del(&ev->list);
5645 kfree(ev);
5646 }
5647 }
5648
1af8efe9 5649 spin_unlock(&memcg_oom_lock);
9490ff27
KH
5650}
5651
2da8ca82 5652static int mem_cgroup_oom_control_read(struct seq_file *sf, void *v)
3c11ecf4 5653{
2da8ca82 5654 struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(sf));
3c11ecf4 5655
791badbd
TH
5656 seq_printf(sf, "oom_kill_disable %d\n", memcg->oom_kill_disable);
5657 seq_printf(sf, "under_oom %d\n", (bool)atomic_read(&memcg->under_oom));
3c11ecf4
KH
5658 return 0;
5659}
5660
182446d0 5661static int mem_cgroup_oom_control_write(struct cgroup_subsys_state *css,
3c11ecf4
KH
5662 struct cftype *cft, u64 val)
5663{
182446d0 5664 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
3c11ecf4
KH
5665
5666 /* cannot set to root cgroup and only 0 and 1 are allowed */
14208b0e 5667 if (!css->parent || !((val == 0) || (val == 1)))
3c11ecf4
KH
5668 return -EINVAL;
5669
c0ff4b85 5670 memcg->oom_kill_disable = val;
4d845ebf 5671 if (!val)
c0ff4b85 5672 memcg_oom_recover(memcg);
3dae7fec 5673
3c11ecf4
KH
5674 return 0;
5675}
5676
c255a458 5677#ifdef CONFIG_MEMCG_KMEM
cbe128e3 5678static int memcg_init_kmem(struct mem_cgroup *memcg, struct cgroup_subsys *ss)
e5671dfa 5679{
55007d84
GC
5680 int ret;
5681
2633d7a0 5682 memcg->kmemcg_id = -1;
55007d84
GC
5683 ret = memcg_propagate_kmem(memcg);
5684 if (ret)
5685 return ret;
2633d7a0 5686
1d62e436 5687 return mem_cgroup_sockets_init(memcg, ss);
573b400d 5688}
e5671dfa 5689
10d5ebf4 5690static void memcg_destroy_kmem(struct mem_cgroup *memcg)
d1a4c0b3 5691{
1d62e436 5692 mem_cgroup_sockets_destroy(memcg);
10d5ebf4
LZ
5693}
5694
5695static void kmem_cgroup_css_offline(struct mem_cgroup *memcg)
5696{
5697 if (!memcg_kmem_is_active(memcg))
5698 return;
5699
5700 /*
5701 * kmem charges can outlive the cgroup. In the case of slab
5702 * pages, for instance, a page contain objects from various
5703 * processes. As we prevent from taking a reference for every
5704 * such allocation we have to be careful when doing uncharge
5705 * (see memcg_uncharge_kmem) and here during offlining.
5706 *
5707 * The idea is that that only the _last_ uncharge which sees
5708 * the dead memcg will drop the last reference. An additional
5709 * reference is taken here before the group is marked dead
5710 * which is then paired with css_put during uncharge resp. here.
5711 *
5712 * Although this might sound strange as this path is called from
ec903c0c
TH
5713 * css_offline() when the referencemight have dropped down to 0 and
5714 * shouldn't be incremented anymore (css_tryget_online() would
5715 * fail) we do not have other options because of the kmem
5716 * allocations lifetime.
10d5ebf4
LZ
5717 */
5718 css_get(&memcg->css);
7de37682
GC
5719
5720 memcg_kmem_mark_dead(memcg);
5721
5722 if (res_counter_read_u64(&memcg->kmem, RES_USAGE) != 0)
5723 return;
5724
7de37682 5725 if (memcg_kmem_test_and_clear_dead(memcg))
10d5ebf4 5726 css_put(&memcg->css);
d1a4c0b3 5727}
e5671dfa 5728#else
cbe128e3 5729static int memcg_init_kmem(struct mem_cgroup *memcg, struct cgroup_subsys *ss)
e5671dfa
GC
5730{
5731 return 0;
5732}
d1a4c0b3 5733
10d5ebf4
LZ
5734static void memcg_destroy_kmem(struct mem_cgroup *memcg)
5735{
5736}
5737
5738static void kmem_cgroup_css_offline(struct mem_cgroup *memcg)
d1a4c0b3
GC
5739{
5740}
e5671dfa
GC
5741#endif
5742
3bc942f3
TH
5743/*
5744 * DO NOT USE IN NEW FILES.
5745 *
5746 * "cgroup.event_control" implementation.
5747 *
5748 * This is way over-engineered. It tries to support fully configurable
5749 * events for each user. Such level of flexibility is completely
5750 * unnecessary especially in the light of the planned unified hierarchy.
5751 *
5752 * Please deprecate this and replace with something simpler if at all
5753 * possible.
5754 */
5755
79bd9814
TH
5756/*
5757 * Unregister event and free resources.
5758 *
5759 * Gets called from workqueue.
5760 */
3bc942f3 5761static void memcg_event_remove(struct work_struct *work)
79bd9814 5762{
3bc942f3
TH
5763 struct mem_cgroup_event *event =
5764 container_of(work, struct mem_cgroup_event, remove);
59b6f873 5765 struct mem_cgroup *memcg = event->memcg;
79bd9814
TH
5766
5767 remove_wait_queue(event->wqh, &event->wait);
5768
59b6f873 5769 event->unregister_event(memcg, event->eventfd);
79bd9814
TH
5770
5771 /* Notify userspace the event is going away. */
5772 eventfd_signal(event->eventfd, 1);
5773
5774 eventfd_ctx_put(event->eventfd);
5775 kfree(event);
59b6f873 5776 css_put(&memcg->css);
79bd9814
TH
5777}
5778
5779/*
5780 * Gets called on POLLHUP on eventfd when user closes it.
5781 *
5782 * Called with wqh->lock held and interrupts disabled.
5783 */
3bc942f3
TH
5784static int memcg_event_wake(wait_queue_t *wait, unsigned mode,
5785 int sync, void *key)
79bd9814 5786{
3bc942f3
TH
5787 struct mem_cgroup_event *event =
5788 container_of(wait, struct mem_cgroup_event, wait);
59b6f873 5789 struct mem_cgroup *memcg = event->memcg;
79bd9814
TH
5790 unsigned long flags = (unsigned long)key;
5791
5792 if (flags & POLLHUP) {
5793 /*
5794 * If the event has been detached at cgroup removal, we
5795 * can simply return knowing the other side will cleanup
5796 * for us.
5797 *
5798 * We can't race against event freeing since the other
5799 * side will require wqh->lock via remove_wait_queue(),
5800 * which we hold.
5801 */
fba94807 5802 spin_lock(&memcg->event_list_lock);
79bd9814
TH
5803 if (!list_empty(&event->list)) {
5804 list_del_init(&event->list);
5805 /*
5806 * We are in atomic context, but cgroup_event_remove()
5807 * may sleep, so we have to call it in workqueue.
5808 */
5809 schedule_work(&event->remove);
5810 }
fba94807 5811 spin_unlock(&memcg->event_list_lock);
79bd9814
TH
5812 }
5813
5814 return 0;
5815}
5816
3bc942f3 5817static void memcg_event_ptable_queue_proc(struct file *file,
79bd9814
TH
5818 wait_queue_head_t *wqh, poll_table *pt)
5819{
3bc942f3
TH
5820 struct mem_cgroup_event *event =
5821 container_of(pt, struct mem_cgroup_event, pt);
79bd9814
TH
5822
5823 event->wqh = wqh;
5824 add_wait_queue(wqh, &event->wait);
5825}
5826
5827/*
3bc942f3
TH
5828 * DO NOT USE IN NEW FILES.
5829 *
79bd9814
TH
5830 * Parse input and register new cgroup event handler.
5831 *
5832 * Input must be in format '<event_fd> <control_fd> <args>'.
5833 * Interpretation of args is defined by control file implementation.
5834 */
451af504
TH
5835static ssize_t memcg_write_event_control(struct kernfs_open_file *of,
5836 char *buf, size_t nbytes, loff_t off)
79bd9814 5837{
451af504 5838 struct cgroup_subsys_state *css = of_css(of);
fba94807 5839 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
3bc942f3 5840 struct mem_cgroup_event *event;
79bd9814
TH
5841 struct cgroup_subsys_state *cfile_css;
5842 unsigned int efd, cfd;
5843 struct fd efile;
5844 struct fd cfile;
fba94807 5845 const char *name;
79bd9814
TH
5846 char *endp;
5847 int ret;
5848
451af504
TH
5849 buf = strstrip(buf);
5850
5851 efd = simple_strtoul(buf, &endp, 10);
79bd9814
TH
5852 if (*endp != ' ')
5853 return -EINVAL;
451af504 5854 buf = endp + 1;
79bd9814 5855
451af504 5856 cfd = simple_strtoul(buf, &endp, 10);
79bd9814
TH
5857 if ((*endp != ' ') && (*endp != '\0'))
5858 return -EINVAL;
451af504 5859 buf = endp + 1;
79bd9814
TH
5860
5861 event = kzalloc(sizeof(*event), GFP_KERNEL);
5862 if (!event)
5863 return -ENOMEM;
5864
59b6f873 5865 event->memcg = memcg;
79bd9814 5866 INIT_LIST_HEAD(&event->list);
3bc942f3
TH
5867 init_poll_funcptr(&event->pt, memcg_event_ptable_queue_proc);
5868 init_waitqueue_func_entry(&event->wait, memcg_event_wake);
5869 INIT_WORK(&event->remove, memcg_event_remove);
79bd9814
TH
5870
5871 efile = fdget(efd);
5872 if (!efile.file) {
5873 ret = -EBADF;
5874 goto out_kfree;
5875 }
5876
5877 event->eventfd = eventfd_ctx_fileget(efile.file);
5878 if (IS_ERR(event->eventfd)) {
5879 ret = PTR_ERR(event->eventfd);
5880 goto out_put_efile;
5881 }
5882
5883 cfile = fdget(cfd);
5884 if (!cfile.file) {
5885 ret = -EBADF;
5886 goto out_put_eventfd;
5887 }
5888
5889 /* the process need read permission on control file */
5890 /* AV: shouldn't we check that it's been opened for read instead? */
5891 ret = inode_permission(file_inode(cfile.file), MAY_READ);
5892 if (ret < 0)
5893 goto out_put_cfile;
5894
fba94807
TH
5895 /*
5896 * Determine the event callbacks and set them in @event. This used
5897 * to be done via struct cftype but cgroup core no longer knows
5898 * about these events. The following is crude but the whole thing
5899 * is for compatibility anyway.
3bc942f3
TH
5900 *
5901 * DO NOT ADD NEW FILES.
fba94807
TH
5902 */
5903 name = cfile.file->f_dentry->d_name.name;
5904
5905 if (!strcmp(name, "memory.usage_in_bytes")) {
5906 event->register_event = mem_cgroup_usage_register_event;
5907 event->unregister_event = mem_cgroup_usage_unregister_event;
5908 } else if (!strcmp(name, "memory.oom_control")) {
5909 event->register_event = mem_cgroup_oom_register_event;
5910 event->unregister_event = mem_cgroup_oom_unregister_event;
5911 } else if (!strcmp(name, "memory.pressure_level")) {
5912 event->register_event = vmpressure_register_event;
5913 event->unregister_event = vmpressure_unregister_event;
5914 } else if (!strcmp(name, "memory.memsw.usage_in_bytes")) {
347c4a87
TH
5915 event->register_event = memsw_cgroup_usage_register_event;
5916 event->unregister_event = memsw_cgroup_usage_unregister_event;
fba94807
TH
5917 } else {
5918 ret = -EINVAL;
5919 goto out_put_cfile;
5920 }
5921
79bd9814 5922 /*
b5557c4c
TH
5923 * Verify @cfile should belong to @css. Also, remaining events are
5924 * automatically removed on cgroup destruction but the removal is
5925 * asynchronous, so take an extra ref on @css.
79bd9814 5926 */
ec903c0c
TH
5927 cfile_css = css_tryget_online_from_dir(cfile.file->f_dentry->d_parent,
5928 &memory_cgrp_subsys);
79bd9814 5929 ret = -EINVAL;
5a17f543 5930 if (IS_ERR(cfile_css))
79bd9814 5931 goto out_put_cfile;
5a17f543
TH
5932 if (cfile_css != css) {
5933 css_put(cfile_css);
79bd9814 5934 goto out_put_cfile;
5a17f543 5935 }
79bd9814 5936
451af504 5937 ret = event->register_event(memcg, event->eventfd, buf);
79bd9814
TH
5938 if (ret)
5939 goto out_put_css;
5940
5941 efile.file->f_op->poll(efile.file, &event->pt);
5942
fba94807
TH
5943 spin_lock(&memcg->event_list_lock);
5944 list_add(&event->list, &memcg->event_list);
5945 spin_unlock(&memcg->event_list_lock);
79bd9814
TH
5946
5947 fdput(cfile);
5948 fdput(efile);
5949
451af504 5950 return nbytes;
79bd9814
TH
5951
5952out_put_css:
b5557c4c 5953 css_put(css);
79bd9814
TH
5954out_put_cfile:
5955 fdput(cfile);
5956out_put_eventfd:
5957 eventfd_ctx_put(event->eventfd);
5958out_put_efile:
5959 fdput(efile);
5960out_kfree:
5961 kfree(event);
5962
5963 return ret;
5964}
5965
8cdea7c0
BS
5966static struct cftype mem_cgroup_files[] = {
5967 {
0eea1030 5968 .name = "usage_in_bytes",
8c7c6e34 5969 .private = MEMFILE_PRIVATE(_MEM, RES_USAGE),
791badbd 5970 .read_u64 = mem_cgroup_read_u64,
8cdea7c0 5971 },
c84872e1
PE
5972 {
5973 .name = "max_usage_in_bytes",
8c7c6e34 5974 .private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE),
6770c64e 5975 .write = mem_cgroup_reset,
791badbd 5976 .read_u64 = mem_cgroup_read_u64,
c84872e1 5977 },
8cdea7c0 5978 {
0eea1030 5979 .name = "limit_in_bytes",
8c7c6e34 5980 .private = MEMFILE_PRIVATE(_MEM, RES_LIMIT),
451af504 5981 .write = mem_cgroup_write,
791badbd 5982 .read_u64 = mem_cgroup_read_u64,
8cdea7c0 5983 },
296c81d8
BS
5984 {
5985 .name = "soft_limit_in_bytes",
5986 .private = MEMFILE_PRIVATE(_MEM, RES_SOFT_LIMIT),
451af504 5987 .write = mem_cgroup_write,
791badbd 5988 .read_u64 = mem_cgroup_read_u64,
296c81d8 5989 },
8cdea7c0
BS
5990 {
5991 .name = "failcnt",
8c7c6e34 5992 .private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT),
6770c64e 5993 .write = mem_cgroup_reset,
791badbd 5994 .read_u64 = mem_cgroup_read_u64,
8cdea7c0 5995 },
d2ceb9b7
KH
5996 {
5997 .name = "stat",
2da8ca82 5998 .seq_show = memcg_stat_show,
d2ceb9b7 5999 },
c1e862c1
KH
6000 {
6001 .name = "force_empty",
6770c64e 6002 .write = mem_cgroup_force_empty_write,
c1e862c1 6003 },
18f59ea7
BS
6004 {
6005 .name = "use_hierarchy",
f00baae7 6006 .flags = CFTYPE_INSANE,
18f59ea7
BS
6007 .write_u64 = mem_cgroup_hierarchy_write,
6008 .read_u64 = mem_cgroup_hierarchy_read,
6009 },
79bd9814 6010 {
3bc942f3 6011 .name = "cgroup.event_control", /* XXX: for compat */
451af504 6012 .write = memcg_write_event_control,
79bd9814
TH
6013 .flags = CFTYPE_NO_PREFIX,
6014 .mode = S_IWUGO,
6015 },
a7885eb8
KM
6016 {
6017 .name = "swappiness",
6018 .read_u64 = mem_cgroup_swappiness_read,
6019 .write_u64 = mem_cgroup_swappiness_write,
6020 },
7dc74be0
DN
6021 {
6022 .name = "move_charge_at_immigrate",
6023 .read_u64 = mem_cgroup_move_charge_read,
6024 .write_u64 = mem_cgroup_move_charge_write,
6025 },
9490ff27
KH
6026 {
6027 .name = "oom_control",
2da8ca82 6028 .seq_show = mem_cgroup_oom_control_read,
3c11ecf4 6029 .write_u64 = mem_cgroup_oom_control_write,
9490ff27
KH
6030 .private = MEMFILE_PRIVATE(_OOM_TYPE, OOM_CONTROL),
6031 },
70ddf637
AV
6032 {
6033 .name = "pressure_level",
70ddf637 6034 },
406eb0c9
YH
6035#ifdef CONFIG_NUMA
6036 {
6037 .name = "numa_stat",
2da8ca82 6038 .seq_show = memcg_numa_stat_show,
406eb0c9
YH
6039 },
6040#endif
510fc4e1
GC
6041#ifdef CONFIG_MEMCG_KMEM
6042 {
6043 .name = "kmem.limit_in_bytes",
6044 .private = MEMFILE_PRIVATE(_KMEM, RES_LIMIT),
451af504 6045 .write = mem_cgroup_write,
791badbd 6046 .read_u64 = mem_cgroup_read_u64,
510fc4e1
GC
6047 },
6048 {
6049 .name = "kmem.usage_in_bytes",
6050 .private = MEMFILE_PRIVATE(_KMEM, RES_USAGE),
791badbd 6051 .read_u64 = mem_cgroup_read_u64,
510fc4e1
GC
6052 },
6053 {
6054 .name = "kmem.failcnt",
6055 .private = MEMFILE_PRIVATE(_KMEM, RES_FAILCNT),
6770c64e 6056 .write = mem_cgroup_reset,
791badbd 6057 .read_u64 = mem_cgroup_read_u64,
510fc4e1
GC
6058 },
6059 {
6060 .name = "kmem.max_usage_in_bytes",
6061 .private = MEMFILE_PRIVATE(_KMEM, RES_MAX_USAGE),
6770c64e 6062 .write = mem_cgroup_reset,
791badbd 6063 .read_u64 = mem_cgroup_read_u64,
510fc4e1 6064 },
749c5415
GC
6065#ifdef CONFIG_SLABINFO
6066 {
6067 .name = "kmem.slabinfo",
2da8ca82 6068 .seq_show = mem_cgroup_slabinfo_read,
749c5415
GC
6069 },
6070#endif
8c7c6e34 6071#endif
6bc10349 6072 { }, /* terminate */
af36f906 6073};
8c7c6e34 6074
2d11085e
MH
6075#ifdef CONFIG_MEMCG_SWAP
6076static struct cftype memsw_cgroup_files[] = {
6077 {
6078 .name = "memsw.usage_in_bytes",
6079 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE),
791badbd 6080 .read_u64 = mem_cgroup_read_u64,
2d11085e
MH
6081 },
6082 {
6083 .name = "memsw.max_usage_in_bytes",
6084 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE),
6770c64e 6085 .write = mem_cgroup_reset,
791badbd 6086 .read_u64 = mem_cgroup_read_u64,
2d11085e
MH
6087 },
6088 {
6089 .name = "memsw.limit_in_bytes",
6090 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT),
451af504 6091 .write = mem_cgroup_write,
791badbd 6092 .read_u64 = mem_cgroup_read_u64,
2d11085e
MH
6093 },
6094 {
6095 .name = "memsw.failcnt",
6096 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT),
6770c64e 6097 .write = mem_cgroup_reset,
791badbd 6098 .read_u64 = mem_cgroup_read_u64,
2d11085e
MH
6099 },
6100 { }, /* terminate */
6101};
6102#endif
c0ff4b85 6103static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *memcg, int node)
6d12e2d8
KH
6104{
6105 struct mem_cgroup_per_node *pn;
1ecaab2b 6106 struct mem_cgroup_per_zone *mz;
41e3355d 6107 int zone, tmp = node;
1ecaab2b
KH
6108 /*
6109 * This routine is called against possible nodes.
6110 * But it's BUG to call kmalloc() against offline node.
6111 *
6112 * TODO: this routine can waste much memory for nodes which will
6113 * never be onlined. It's better to use memory hotplug callback
6114 * function.
6115 */
41e3355d
KH
6116 if (!node_state(node, N_NORMAL_MEMORY))
6117 tmp = -1;
17295c88 6118 pn = kzalloc_node(sizeof(*pn), GFP_KERNEL, tmp);
6d12e2d8
KH
6119 if (!pn)
6120 return 1;
1ecaab2b 6121
1ecaab2b
KH
6122 for (zone = 0; zone < MAX_NR_ZONES; zone++) {
6123 mz = &pn->zoneinfo[zone];
bea8c150 6124 lruvec_init(&mz->lruvec);
bb4cc1a8
AM
6125 mz->usage_in_excess = 0;
6126 mz->on_tree = false;
d79154bb 6127 mz->memcg = memcg;
1ecaab2b 6128 }
54f72fe0 6129 memcg->nodeinfo[node] = pn;
6d12e2d8
KH
6130 return 0;
6131}
6132
c0ff4b85 6133static void free_mem_cgroup_per_zone_info(struct mem_cgroup *memcg, int node)
1ecaab2b 6134{
54f72fe0 6135 kfree(memcg->nodeinfo[node]);
1ecaab2b
KH
6136}
6137
33327948
KH
6138static struct mem_cgroup *mem_cgroup_alloc(void)
6139{
d79154bb 6140 struct mem_cgroup *memcg;
8ff69e2c 6141 size_t size;
33327948 6142
8ff69e2c
VD
6143 size = sizeof(struct mem_cgroup);
6144 size += nr_node_ids * sizeof(struct mem_cgroup_per_node *);
33327948 6145
8ff69e2c 6146 memcg = kzalloc(size, GFP_KERNEL);
d79154bb 6147 if (!memcg)
e7bbcdf3
DC
6148 return NULL;
6149
d79154bb
HD
6150 memcg->stat = alloc_percpu(struct mem_cgroup_stat_cpu);
6151 if (!memcg->stat)
d2e61b8d 6152 goto out_free;
d79154bb
HD
6153 spin_lock_init(&memcg->pcp_counter_lock);
6154 return memcg;
d2e61b8d
DC
6155
6156out_free:
8ff69e2c 6157 kfree(memcg);
d2e61b8d 6158 return NULL;
33327948
KH
6159}
6160
59927fb9 6161/*
c8b2a36f
GC
6162 * At destroying mem_cgroup, references from swap_cgroup can remain.
6163 * (scanning all at force_empty is too costly...)
6164 *
6165 * Instead of clearing all references at force_empty, we remember
6166 * the number of reference from swap_cgroup and free mem_cgroup when
6167 * it goes down to 0.
6168 *
6169 * Removal of cgroup itself succeeds regardless of refs from swap.
59927fb9 6170 */
c8b2a36f
GC
6171
6172static void __mem_cgroup_free(struct mem_cgroup *memcg)
59927fb9 6173{
c8b2a36f 6174 int node;
59927fb9 6175
bb4cc1a8 6176 mem_cgroup_remove_from_trees(memcg);
c8b2a36f
GC
6177
6178 for_each_node(node)
6179 free_mem_cgroup_per_zone_info(memcg, node);
6180
6181 free_percpu(memcg->stat);
6182
3f134619
GC
6183 /*
6184 * We need to make sure that (at least for now), the jump label
6185 * destruction code runs outside of the cgroup lock. This is because
6186 * get_online_cpus(), which is called from the static_branch update,
6187 * can't be called inside the cgroup_lock. cpusets are the ones
6188 * enforcing this dependency, so if they ever change, we might as well.
6189 *
6190 * schedule_work() will guarantee this happens. Be careful if you need
6191 * to move this code around, and make sure it is outside
6192 * the cgroup_lock.
6193 */
a8964b9b 6194 disarm_static_keys(memcg);
8ff69e2c 6195 kfree(memcg);
59927fb9 6196}
3afe36b1 6197
7bcc1bb1
DN
6198/*
6199 * Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled.
6200 */
e1aab161 6201struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *memcg)
7bcc1bb1 6202{
c0ff4b85 6203 if (!memcg->res.parent)
7bcc1bb1 6204 return NULL;
c0ff4b85 6205 return mem_cgroup_from_res_counter(memcg->res.parent, res);
7bcc1bb1 6206}
e1aab161 6207EXPORT_SYMBOL(parent_mem_cgroup);
33327948 6208
bb4cc1a8
AM
6209static void __init mem_cgroup_soft_limit_tree_init(void)
6210{
6211 struct mem_cgroup_tree_per_node *rtpn;
6212 struct mem_cgroup_tree_per_zone *rtpz;
6213 int tmp, node, zone;
6214
6215 for_each_node(node) {
6216 tmp = node;
6217 if (!node_state(node, N_NORMAL_MEMORY))
6218 tmp = -1;
6219 rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL, tmp);
6220 BUG_ON(!rtpn);
6221
6222 soft_limit_tree.rb_tree_per_node[node] = rtpn;
6223
6224 for (zone = 0; zone < MAX_NR_ZONES; zone++) {
6225 rtpz = &rtpn->rb_tree_per_zone[zone];
6226 rtpz->rb_root = RB_ROOT;
6227 spin_lock_init(&rtpz->lock);
6228 }
6229 }
6230}
6231
0eb253e2 6232static struct cgroup_subsys_state * __ref
eb95419b 6233mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
8cdea7c0 6234{
d142e3e6 6235 struct mem_cgroup *memcg;
04046e1a 6236 long error = -ENOMEM;
6d12e2d8 6237 int node;
8cdea7c0 6238
c0ff4b85
R
6239 memcg = mem_cgroup_alloc();
6240 if (!memcg)
04046e1a 6241 return ERR_PTR(error);
78fb7466 6242
3ed28fa1 6243 for_each_node(node)
c0ff4b85 6244 if (alloc_mem_cgroup_per_zone_info(memcg, node))
6d12e2d8 6245 goto free_out;
f64c3f54 6246
c077719b 6247 /* root ? */
eb95419b 6248 if (parent_css == NULL) {
a41c58a6 6249 root_mem_cgroup = memcg;
d142e3e6
GC
6250 res_counter_init(&memcg->res, NULL);
6251 res_counter_init(&memcg->memsw, NULL);
6252 res_counter_init(&memcg->kmem, NULL);
18f59ea7 6253 }
28dbc4b6 6254
d142e3e6
GC
6255 memcg->last_scanned_node = MAX_NUMNODES;
6256 INIT_LIST_HEAD(&memcg->oom_notify);
d142e3e6
GC
6257 memcg->move_charge_at_immigrate = 0;
6258 mutex_init(&memcg->thresholds_lock);
6259 spin_lock_init(&memcg->move_lock);
70ddf637 6260 vmpressure_init(&memcg->vmpressure);
fba94807
TH
6261 INIT_LIST_HEAD(&memcg->event_list);
6262 spin_lock_init(&memcg->event_list_lock);
d142e3e6
GC
6263
6264 return &memcg->css;
6265
6266free_out:
6267 __mem_cgroup_free(memcg);
6268 return ERR_PTR(error);
6269}
6270
6271static int
eb95419b 6272mem_cgroup_css_online(struct cgroup_subsys_state *css)
d142e3e6 6273{
eb95419b 6274 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5c9d535b 6275 struct mem_cgroup *parent = mem_cgroup_from_css(css->parent);
d142e3e6 6276
15a4c835 6277 if (css->id > MEM_CGROUP_ID_MAX)
4219b2da
LZ
6278 return -ENOSPC;
6279
63876986 6280 if (!parent)
d142e3e6
GC
6281 return 0;
6282
0999821b 6283 mutex_lock(&memcg_create_mutex);
d142e3e6
GC
6284
6285 memcg->use_hierarchy = parent->use_hierarchy;
6286 memcg->oom_kill_disable = parent->oom_kill_disable;
6287 memcg->swappiness = mem_cgroup_swappiness(parent);
6288
6289 if (parent->use_hierarchy) {
c0ff4b85
R
6290 res_counter_init(&memcg->res, &parent->res);
6291 res_counter_init(&memcg->memsw, &parent->memsw);
510fc4e1 6292 res_counter_init(&memcg->kmem, &parent->kmem);
55007d84 6293
7bcc1bb1 6294 /*
8d76a979
LZ
6295 * No need to take a reference to the parent because cgroup
6296 * core guarantees its existence.
7bcc1bb1 6297 */
18f59ea7 6298 } else {
c0ff4b85
R
6299 res_counter_init(&memcg->res, NULL);
6300 res_counter_init(&memcg->memsw, NULL);
510fc4e1 6301 res_counter_init(&memcg->kmem, NULL);
8c7f6edb
TH
6302 /*
6303 * Deeper hierachy with use_hierarchy == false doesn't make
6304 * much sense so let cgroup subsystem know about this
6305 * unfortunate state in our controller.
6306 */
d142e3e6 6307 if (parent != root_mem_cgroup)
073219e9 6308 memory_cgrp_subsys.broken_hierarchy = true;
18f59ea7 6309 }
0999821b 6310 mutex_unlock(&memcg_create_mutex);
d6441637 6311
073219e9 6312 return memcg_init_kmem(memcg, &memory_cgrp_subsys);
8cdea7c0
BS
6313}
6314
5f578161
MH
6315/*
6316 * Announce all parents that a group from their hierarchy is gone.
6317 */
6318static void mem_cgroup_invalidate_reclaim_iterators(struct mem_cgroup *memcg)
6319{
6320 struct mem_cgroup *parent = memcg;
6321
6322 while ((parent = parent_mem_cgroup(parent)))
519ebea3 6323 mem_cgroup_iter_invalidate(parent);
5f578161
MH
6324
6325 /*
6326 * if the root memcg is not hierarchical we have to check it
6327 * explicitely.
6328 */
6329 if (!root_mem_cgroup->use_hierarchy)
519ebea3 6330 mem_cgroup_iter_invalidate(root_mem_cgroup);
5f578161
MH
6331}
6332
eb95419b 6333static void mem_cgroup_css_offline(struct cgroup_subsys_state *css)
df878fb0 6334{
eb95419b 6335 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
3bc942f3 6336 struct mem_cgroup_event *event, *tmp;
4fb1a86f 6337 struct cgroup_subsys_state *iter;
79bd9814
TH
6338
6339 /*
6340 * Unregister events and notify userspace.
6341 * Notify userspace about cgroup removing only after rmdir of cgroup
6342 * directory to avoid race between userspace and kernelspace.
6343 */
fba94807
TH
6344 spin_lock(&memcg->event_list_lock);
6345 list_for_each_entry_safe(event, tmp, &memcg->event_list, list) {
79bd9814
TH
6346 list_del_init(&event->list);
6347 schedule_work(&event->remove);
6348 }
fba94807 6349 spin_unlock(&memcg->event_list_lock);
ec64f515 6350
10d5ebf4
LZ
6351 kmem_cgroup_css_offline(memcg);
6352
5f578161 6353 mem_cgroup_invalidate_reclaim_iterators(memcg);
4fb1a86f
FB
6354
6355 /*
6356 * This requires that offlining is serialized. Right now that is
6357 * guaranteed because css_killed_work_fn() holds the cgroup_mutex.
6358 */
6359 css_for_each_descendant_post(iter, css)
6360 mem_cgroup_reparent_charges(mem_cgroup_from_css(iter));
6361
776ed0f0 6362 memcg_unregister_all_caches(memcg);
33cb876e 6363 vmpressure_cleanup(&memcg->vmpressure);
df878fb0
KH
6364}
6365
eb95419b 6366static void mem_cgroup_css_free(struct cgroup_subsys_state *css)
8cdea7c0 6367{
eb95419b 6368 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
96f1c58d
JW
6369 /*
6370 * XXX: css_offline() would be where we should reparent all
6371 * memory to prepare the cgroup for destruction. However,
ec903c0c 6372 * memcg does not do css_tryget_online() and res_counter charging
96f1c58d
JW
6373 * under the same RCU lock region, which means that charging
6374 * could race with offlining. Offlining only happens to
6375 * cgroups with no tasks in them but charges can show up
6376 * without any tasks from the swapin path when the target
6377 * memcg is looked up from the swapout record and not from the
6378 * current task as it usually is. A race like this can leak
6379 * charges and put pages with stale cgroup pointers into
6380 * circulation:
6381 *
6382 * #0 #1
6383 * lookup_swap_cgroup_id()
6384 * rcu_read_lock()
6385 * mem_cgroup_lookup()
ec903c0c 6386 * css_tryget_online()
96f1c58d 6387 * rcu_read_unlock()
ec903c0c 6388 * disable css_tryget_online()
96f1c58d
JW
6389 * call_rcu()
6390 * offline_css()
6391 * reparent_charges()
6392 * res_counter_charge()
6393 * css_put()
6394 * css_free()
6395 * pc->mem_cgroup = dead memcg
6396 * add page to lru
6397 *
6398 * The bulk of the charges are still moved in offline_css() to
6399 * avoid pinning a lot of pages in case a long-term reference
6400 * like a swapout record is deferring the css_free() to long
6401 * after offlining. But this makes sure we catch any charges
6402 * made after offlining:
6403 */
6404 mem_cgroup_reparent_charges(memcg);
c268e994 6405
10d5ebf4 6406 memcg_destroy_kmem(memcg);
465939a1 6407 __mem_cgroup_free(memcg);
8cdea7c0
BS
6408}
6409
1ced953b
TH
6410/**
6411 * mem_cgroup_css_reset - reset the states of a mem_cgroup
6412 * @css: the target css
6413 *
6414 * Reset the states of the mem_cgroup associated with @css. This is
6415 * invoked when the userland requests disabling on the default hierarchy
6416 * but the memcg is pinned through dependency. The memcg should stop
6417 * applying policies and should revert to the vanilla state as it may be
6418 * made visible again.
6419 *
6420 * The current implementation only resets the essential configurations.
6421 * This needs to be expanded to cover all the visible parts.
6422 */
6423static void mem_cgroup_css_reset(struct cgroup_subsys_state *css)
6424{
6425 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
6426
6427 mem_cgroup_resize_limit(memcg, ULLONG_MAX);
6428 mem_cgroup_resize_memsw_limit(memcg, ULLONG_MAX);
6429 memcg_update_kmem_limit(memcg, ULLONG_MAX);
6430 res_counter_set_soft_limit(&memcg->res, ULLONG_MAX);
6431}
6432
02491447 6433#ifdef CONFIG_MMU
7dc74be0 6434/* Handlers for move charge at task migration. */
854ffa8d
DN
6435#define PRECHARGE_COUNT_AT_ONCE 256
6436static int mem_cgroup_do_precharge(unsigned long count)
7dc74be0 6437{
854ffa8d
DN
6438 int ret = 0;
6439 int batch_count = PRECHARGE_COUNT_AT_ONCE;
c0ff4b85 6440 struct mem_cgroup *memcg = mc.to;
4ffef5fe 6441
c0ff4b85 6442 if (mem_cgroup_is_root(memcg)) {
854ffa8d
DN
6443 mc.precharge += count;
6444 /* we don't need css_get for root */
6445 return ret;
6446 }
6447 /* try to charge at once */
6448 if (count > 1) {
6449 struct res_counter *dummy;
6450 /*
c0ff4b85 6451 * "memcg" cannot be under rmdir() because we've already checked
854ffa8d
DN
6452 * by cgroup_lock_live_cgroup() that it is not removed and we
6453 * are still under the same cgroup_mutex. So we can postpone
6454 * css_get().
6455 */
c0ff4b85 6456 if (res_counter_charge(&memcg->res, PAGE_SIZE * count, &dummy))
854ffa8d 6457 goto one_by_one;
c0ff4b85 6458 if (do_swap_account && res_counter_charge(&memcg->memsw,
854ffa8d 6459 PAGE_SIZE * count, &dummy)) {
c0ff4b85 6460 res_counter_uncharge(&memcg->res, PAGE_SIZE * count);
854ffa8d
DN
6461 goto one_by_one;
6462 }
6463 mc.precharge += count;
854ffa8d
DN
6464 return ret;
6465 }
6466one_by_one:
6467 /* fall back to one by one charge */
6468 while (count--) {
6469 if (signal_pending(current)) {
6470 ret = -EINTR;
6471 break;
6472 }
6473 if (!batch_count--) {
6474 batch_count = PRECHARGE_COUNT_AT_ONCE;
6475 cond_resched();
6476 }
6d1fdc48 6477 ret = mem_cgroup_try_charge(memcg, GFP_KERNEL, 1, false);
38c5d72f 6478 if (ret)
854ffa8d 6479 /* mem_cgroup_clear_mc() will do uncharge later */
38c5d72f 6480 return ret;
854ffa8d
DN
6481 mc.precharge++;
6482 }
4ffef5fe
DN
6483 return ret;
6484}
6485
6486/**
8d32ff84 6487 * get_mctgt_type - get target type of moving charge
4ffef5fe
DN
6488 * @vma: the vma the pte to be checked belongs
6489 * @addr: the address corresponding to the pte to be checked
6490 * @ptent: the pte to be checked
02491447 6491 * @target: the pointer the target page or swap ent will be stored(can be NULL)
4ffef5fe
DN
6492 *
6493 * Returns
6494 * 0(MC_TARGET_NONE): if the pte is not a target for move charge.
6495 * 1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for
6496 * move charge. if @target is not NULL, the page is stored in target->page
6497 * with extra refcnt got(Callers should handle it).
02491447
DN
6498 * 2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a
6499 * target for charge migration. if @target is not NULL, the entry is stored
6500 * in target->ent.
4ffef5fe
DN
6501 *
6502 * Called with pte lock held.
6503 */
4ffef5fe
DN
6504union mc_target {
6505 struct page *page;
02491447 6506 swp_entry_t ent;
4ffef5fe
DN
6507};
6508
4ffef5fe 6509enum mc_target_type {
8d32ff84 6510 MC_TARGET_NONE = 0,
4ffef5fe 6511 MC_TARGET_PAGE,
02491447 6512 MC_TARGET_SWAP,
4ffef5fe
DN
6513};
6514
90254a65
DN
6515static struct page *mc_handle_present_pte(struct vm_area_struct *vma,
6516 unsigned long addr, pte_t ptent)
4ffef5fe 6517{
90254a65 6518 struct page *page = vm_normal_page(vma, addr, ptent);
4ffef5fe 6519
90254a65
DN
6520 if (!page || !page_mapped(page))
6521 return NULL;
6522 if (PageAnon(page)) {
6523 /* we don't move shared anon */
4b91355e 6524 if (!move_anon())
90254a65 6525 return NULL;
87946a72
DN
6526 } else if (!move_file())
6527 /* we ignore mapcount for file pages */
90254a65
DN
6528 return NULL;
6529 if (!get_page_unless_zero(page))
6530 return NULL;
6531
6532 return page;
6533}
6534
4b91355e 6535#ifdef CONFIG_SWAP
90254a65
DN
6536static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
6537 unsigned long addr, pte_t ptent, swp_entry_t *entry)
6538{
90254a65
DN
6539 struct page *page = NULL;
6540 swp_entry_t ent = pte_to_swp_entry(ptent);
6541
6542 if (!move_anon() || non_swap_entry(ent))
6543 return NULL;
4b91355e
KH
6544 /*
6545 * Because lookup_swap_cache() updates some statistics counter,
6546 * we call find_get_page() with swapper_space directly.
6547 */
33806f06 6548 page = find_get_page(swap_address_space(ent), ent.val);
90254a65
DN
6549 if (do_swap_account)
6550 entry->val = ent.val;
6551
6552 return page;
6553}
4b91355e
KH
6554#else
6555static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
6556 unsigned long addr, pte_t ptent, swp_entry_t *entry)
6557{
6558 return NULL;
6559}
6560#endif
90254a65 6561
87946a72
DN
6562static struct page *mc_handle_file_pte(struct vm_area_struct *vma,
6563 unsigned long addr, pte_t ptent, swp_entry_t *entry)
6564{
6565 struct page *page = NULL;
87946a72
DN
6566 struct address_space *mapping;
6567 pgoff_t pgoff;
6568
6569 if (!vma->vm_file) /* anonymous vma */
6570 return NULL;
6571 if (!move_file())
6572 return NULL;
6573
87946a72
DN
6574 mapping = vma->vm_file->f_mapping;
6575 if (pte_none(ptent))
6576 pgoff = linear_page_index(vma, addr);
6577 else /* pte_file(ptent) is true */
6578 pgoff = pte_to_pgoff(ptent);
6579
6580 /* page is moved even if it's not RSS of this task(page-faulted). */
aa3b1895
HD
6581#ifdef CONFIG_SWAP
6582 /* shmem/tmpfs may report page out on swap: account for that too. */
139b6a6f
JW
6583 if (shmem_mapping(mapping)) {
6584 page = find_get_entry(mapping, pgoff);
6585 if (radix_tree_exceptional_entry(page)) {
6586 swp_entry_t swp = radix_to_swp_entry(page);
6587 if (do_swap_account)
6588 *entry = swp;
6589 page = find_get_page(swap_address_space(swp), swp.val);
6590 }
6591 } else
6592 page = find_get_page(mapping, pgoff);
6593#else
6594 page = find_get_page(mapping, pgoff);
aa3b1895 6595#endif
87946a72
DN
6596 return page;
6597}
6598
8d32ff84 6599static enum mc_target_type get_mctgt_type(struct vm_area_struct *vma,
90254a65
DN
6600 unsigned long addr, pte_t ptent, union mc_target *target)
6601{
6602 struct page *page = NULL;
6603 struct page_cgroup *pc;
8d32ff84 6604 enum mc_target_type ret = MC_TARGET_NONE;
90254a65
DN
6605 swp_entry_t ent = { .val = 0 };
6606
6607 if (pte_present(ptent))
6608 page = mc_handle_present_pte(vma, addr, ptent);
6609 else if (is_swap_pte(ptent))
6610 page = mc_handle_swap_pte(vma, addr, ptent, &ent);
87946a72
DN
6611 else if (pte_none(ptent) || pte_file(ptent))
6612 page = mc_handle_file_pte(vma, addr, ptent, &ent);
90254a65
DN
6613
6614 if (!page && !ent.val)
8d32ff84 6615 return ret;
02491447
DN
6616 if (page) {
6617 pc = lookup_page_cgroup(page);
6618 /*
6619 * Do only loose check w/o page_cgroup lock.
6620 * mem_cgroup_move_account() checks the pc is valid or not under
6621 * the lock.
6622 */
6623 if (PageCgroupUsed(pc) && pc->mem_cgroup == mc.from) {
6624 ret = MC_TARGET_PAGE;
6625 if (target)
6626 target->page = page;
6627 }
6628 if (!ret || !target)
6629 put_page(page);
6630 }
90254a65
DN
6631 /* There is a swap entry and a page doesn't exist or isn't charged */
6632 if (ent.val && !ret &&
34c00c31 6633 mem_cgroup_id(mc.from) == lookup_swap_cgroup_id(ent)) {
7f0f1546
KH
6634 ret = MC_TARGET_SWAP;
6635 if (target)
6636 target->ent = ent;
4ffef5fe 6637 }
4ffef5fe
DN
6638 return ret;
6639}
6640
12724850
NH
6641#ifdef CONFIG_TRANSPARENT_HUGEPAGE
6642/*
6643 * We don't consider swapping or file mapped pages because THP does not
6644 * support them for now.
6645 * Caller should make sure that pmd_trans_huge(pmd) is true.
6646 */
6647static enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma,
6648 unsigned long addr, pmd_t pmd, union mc_target *target)
6649{
6650 struct page *page = NULL;
6651 struct page_cgroup *pc;
6652 enum mc_target_type ret = MC_TARGET_NONE;
6653
6654 page = pmd_page(pmd);
309381fe 6655 VM_BUG_ON_PAGE(!page || !PageHead(page), page);
12724850
NH
6656 if (!move_anon())
6657 return ret;
6658 pc = lookup_page_cgroup(page);
6659 if (PageCgroupUsed(pc) && pc->mem_cgroup == mc.from) {
6660 ret = MC_TARGET_PAGE;
6661 if (target) {
6662 get_page(page);
6663 target->page = page;
6664 }
6665 }
6666 return ret;
6667}
6668#else
6669static inline enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma,
6670 unsigned long addr, pmd_t pmd, union mc_target *target)
6671{
6672 return MC_TARGET_NONE;
6673}
6674#endif
6675
4ffef5fe
DN
6676static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd,
6677 unsigned long addr, unsigned long end,
6678 struct mm_walk *walk)
6679{
6680 struct vm_area_struct *vma = walk->private;
6681 pte_t *pte;
6682 spinlock_t *ptl;
6683
bf929152 6684 if (pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
12724850
NH
6685 if (get_mctgt_type_thp(vma, addr, *pmd, NULL) == MC_TARGET_PAGE)
6686 mc.precharge += HPAGE_PMD_NR;
bf929152 6687 spin_unlock(ptl);
1a5a9906 6688 return 0;
12724850 6689 }
03319327 6690
45f83cef
AA
6691 if (pmd_trans_unstable(pmd))
6692 return 0;
4ffef5fe
DN
6693 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
6694 for (; addr != end; pte++, addr += PAGE_SIZE)
8d32ff84 6695 if (get_mctgt_type(vma, addr, *pte, NULL))
4ffef5fe
DN
6696 mc.precharge++; /* increment precharge temporarily */
6697 pte_unmap_unlock(pte - 1, ptl);
6698 cond_resched();
6699
7dc74be0
DN
6700 return 0;
6701}
6702
4ffef5fe
DN
6703static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm)
6704{
6705 unsigned long precharge;
6706 struct vm_area_struct *vma;
6707
dfe076b0 6708 down_read(&mm->mmap_sem);
4ffef5fe
DN
6709 for (vma = mm->mmap; vma; vma = vma->vm_next) {
6710 struct mm_walk mem_cgroup_count_precharge_walk = {
6711 .pmd_entry = mem_cgroup_count_precharge_pte_range,
6712 .mm = mm,
6713 .private = vma,
6714 };
6715 if (is_vm_hugetlb_page(vma))
6716 continue;
4ffef5fe
DN
6717 walk_page_range(vma->vm_start, vma->vm_end,
6718 &mem_cgroup_count_precharge_walk);
6719 }
dfe076b0 6720 up_read(&mm->mmap_sem);
4ffef5fe
DN
6721
6722 precharge = mc.precharge;
6723 mc.precharge = 0;
6724
6725 return precharge;
6726}
6727
4ffef5fe
DN
6728static int mem_cgroup_precharge_mc(struct mm_struct *mm)
6729{
dfe076b0
DN
6730 unsigned long precharge = mem_cgroup_count_precharge(mm);
6731
6732 VM_BUG_ON(mc.moving_task);
6733 mc.moving_task = current;
6734 return mem_cgroup_do_precharge(precharge);
4ffef5fe
DN
6735}
6736
dfe076b0
DN
6737/* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */
6738static void __mem_cgroup_clear_mc(void)
4ffef5fe 6739{
2bd9bb20
KH
6740 struct mem_cgroup *from = mc.from;
6741 struct mem_cgroup *to = mc.to;
4050377b 6742 int i;
2bd9bb20 6743
4ffef5fe 6744 /* we must uncharge all the leftover precharges from mc.to */
854ffa8d
DN
6745 if (mc.precharge) {
6746 __mem_cgroup_cancel_charge(mc.to, mc.precharge);
6747 mc.precharge = 0;
6748 }
6749 /*
6750 * we didn't uncharge from mc.from at mem_cgroup_move_account(), so
6751 * we must uncharge here.
6752 */
6753 if (mc.moved_charge) {
6754 __mem_cgroup_cancel_charge(mc.from, mc.moved_charge);
6755 mc.moved_charge = 0;
4ffef5fe 6756 }
483c30b5
DN
6757 /* we must fixup refcnts and charges */
6758 if (mc.moved_swap) {
483c30b5
DN
6759 /* uncharge swap account from the old cgroup */
6760 if (!mem_cgroup_is_root(mc.from))
6761 res_counter_uncharge(&mc.from->memsw,
6762 PAGE_SIZE * mc.moved_swap);
4050377b
LZ
6763
6764 for (i = 0; i < mc.moved_swap; i++)
6765 css_put(&mc.from->css);
483c30b5
DN
6766
6767 if (!mem_cgroup_is_root(mc.to)) {
6768 /*
6769 * we charged both to->res and to->memsw, so we should
6770 * uncharge to->res.
6771 */
6772 res_counter_uncharge(&mc.to->res,
6773 PAGE_SIZE * mc.moved_swap);
483c30b5 6774 }
4050377b 6775 /* we've already done css_get(mc.to) */
483c30b5
DN
6776 mc.moved_swap = 0;
6777 }
dfe076b0
DN
6778 memcg_oom_recover(from);
6779 memcg_oom_recover(to);
6780 wake_up_all(&mc.waitq);
6781}
6782
6783static void mem_cgroup_clear_mc(void)
6784{
6785 struct mem_cgroup *from = mc.from;
6786
6787 /*
6788 * we must clear moving_task before waking up waiters at the end of
6789 * task migration.
6790 */
6791 mc.moving_task = NULL;
6792 __mem_cgroup_clear_mc();
2bd9bb20 6793 spin_lock(&mc.lock);
4ffef5fe
DN
6794 mc.from = NULL;
6795 mc.to = NULL;
2bd9bb20 6796 spin_unlock(&mc.lock);
32047e2a 6797 mem_cgroup_end_move(from);
4ffef5fe
DN
6798}
6799
eb95419b 6800static int mem_cgroup_can_attach(struct cgroup_subsys_state *css,
761b3ef5 6801 struct cgroup_taskset *tset)
7dc74be0 6802{
2f7ee569 6803 struct task_struct *p = cgroup_taskset_first(tset);
7dc74be0 6804 int ret = 0;
eb95419b 6805 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
ee5e8472 6806 unsigned long move_charge_at_immigrate;
7dc74be0 6807
ee5e8472
GC
6808 /*
6809 * We are now commited to this value whatever it is. Changes in this
6810 * tunable will only affect upcoming migrations, not the current one.
6811 * So we need to save it, and keep it going.
6812 */
6813 move_charge_at_immigrate = memcg->move_charge_at_immigrate;
6814 if (move_charge_at_immigrate) {
7dc74be0
DN
6815 struct mm_struct *mm;
6816 struct mem_cgroup *from = mem_cgroup_from_task(p);
6817
c0ff4b85 6818 VM_BUG_ON(from == memcg);
7dc74be0
DN
6819
6820 mm = get_task_mm(p);
6821 if (!mm)
6822 return 0;
7dc74be0 6823 /* We move charges only when we move a owner of the mm */
4ffef5fe
DN
6824 if (mm->owner == p) {
6825 VM_BUG_ON(mc.from);
6826 VM_BUG_ON(mc.to);
6827 VM_BUG_ON(mc.precharge);
854ffa8d 6828 VM_BUG_ON(mc.moved_charge);
483c30b5 6829 VM_BUG_ON(mc.moved_swap);
32047e2a 6830 mem_cgroup_start_move(from);
2bd9bb20 6831 spin_lock(&mc.lock);
4ffef5fe 6832 mc.from = from;
c0ff4b85 6833 mc.to = memcg;
ee5e8472 6834 mc.immigrate_flags = move_charge_at_immigrate;
2bd9bb20 6835 spin_unlock(&mc.lock);
dfe076b0 6836 /* We set mc.moving_task later */
4ffef5fe
DN
6837
6838 ret = mem_cgroup_precharge_mc(mm);
6839 if (ret)
6840 mem_cgroup_clear_mc();
dfe076b0
DN
6841 }
6842 mmput(mm);
7dc74be0
DN
6843 }
6844 return ret;
6845}
6846
eb95419b 6847static void mem_cgroup_cancel_attach(struct cgroup_subsys_state *css,
761b3ef5 6848 struct cgroup_taskset *tset)
7dc74be0 6849{
4ffef5fe 6850 mem_cgroup_clear_mc();
7dc74be0
DN
6851}
6852
4ffef5fe
DN
6853static int mem_cgroup_move_charge_pte_range(pmd_t *pmd,
6854 unsigned long addr, unsigned long end,
6855 struct mm_walk *walk)
7dc74be0 6856{
4ffef5fe
DN
6857 int ret = 0;
6858 struct vm_area_struct *vma = walk->private;
6859 pte_t *pte;
6860 spinlock_t *ptl;
12724850
NH
6861 enum mc_target_type target_type;
6862 union mc_target target;
6863 struct page *page;
6864 struct page_cgroup *pc;
4ffef5fe 6865
12724850
NH
6866 /*
6867 * We don't take compound_lock() here but no race with splitting thp
6868 * happens because:
6869 * - if pmd_trans_huge_lock() returns 1, the relevant thp is not
6870 * under splitting, which means there's no concurrent thp split,
6871 * - if another thread runs into split_huge_page() just after we
6872 * entered this if-block, the thread must wait for page table lock
6873 * to be unlocked in __split_huge_page_splitting(), where the main
6874 * part of thp split is not executed yet.
6875 */
bf929152 6876 if (pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
62ade86a 6877 if (mc.precharge < HPAGE_PMD_NR) {
bf929152 6878 spin_unlock(ptl);
12724850
NH
6879 return 0;
6880 }
6881 target_type = get_mctgt_type_thp(vma, addr, *pmd, &target);
6882 if (target_type == MC_TARGET_PAGE) {
6883 page = target.page;
6884 if (!isolate_lru_page(page)) {
6885 pc = lookup_page_cgroup(page);
6886 if (!mem_cgroup_move_account(page, HPAGE_PMD_NR,
2f3479b1 6887 pc, mc.from, mc.to)) {
12724850
NH
6888 mc.precharge -= HPAGE_PMD_NR;
6889 mc.moved_charge += HPAGE_PMD_NR;
6890 }
6891 putback_lru_page(page);
6892 }
6893 put_page(page);
6894 }
bf929152 6895 spin_unlock(ptl);
1a5a9906 6896 return 0;
12724850
NH
6897 }
6898
45f83cef
AA
6899 if (pmd_trans_unstable(pmd))
6900 return 0;
4ffef5fe
DN
6901retry:
6902 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
6903 for (; addr != end; addr += PAGE_SIZE) {
6904 pte_t ptent = *(pte++);
02491447 6905 swp_entry_t ent;
4ffef5fe
DN
6906
6907 if (!mc.precharge)
6908 break;
6909
8d32ff84 6910 switch (get_mctgt_type(vma, addr, ptent, &target)) {
4ffef5fe
DN
6911 case MC_TARGET_PAGE:
6912 page = target.page;
6913 if (isolate_lru_page(page))
6914 goto put;
6915 pc = lookup_page_cgroup(page);
7ec99d62 6916 if (!mem_cgroup_move_account(page, 1, pc,
2f3479b1 6917 mc.from, mc.to)) {
4ffef5fe 6918 mc.precharge--;
854ffa8d
DN
6919 /* we uncharge from mc.from later. */
6920 mc.moved_charge++;
4ffef5fe
DN
6921 }
6922 putback_lru_page(page);
8d32ff84 6923put: /* get_mctgt_type() gets the page */
4ffef5fe
DN
6924 put_page(page);
6925 break;
02491447
DN
6926 case MC_TARGET_SWAP:
6927 ent = target.ent;
e91cbb42 6928 if (!mem_cgroup_move_swap_account(ent, mc.from, mc.to)) {
02491447 6929 mc.precharge--;
483c30b5
DN
6930 /* we fixup refcnts and charges later. */
6931 mc.moved_swap++;
6932 }
02491447 6933 break;
4ffef5fe
DN
6934 default:
6935 break;
6936 }
6937 }
6938 pte_unmap_unlock(pte - 1, ptl);
6939 cond_resched();
6940
6941 if (addr != end) {
6942 /*
6943 * We have consumed all precharges we got in can_attach().
6944 * We try charge one by one, but don't do any additional
6945 * charges to mc.to if we have failed in charge once in attach()
6946 * phase.
6947 */
854ffa8d 6948 ret = mem_cgroup_do_precharge(1);
4ffef5fe
DN
6949 if (!ret)
6950 goto retry;
6951 }
6952
6953 return ret;
6954}
6955
6956static void mem_cgroup_move_charge(struct mm_struct *mm)
6957{
6958 struct vm_area_struct *vma;
6959
6960 lru_add_drain_all();
dfe076b0
DN
6961retry:
6962 if (unlikely(!down_read_trylock(&mm->mmap_sem))) {
6963 /*
6964 * Someone who are holding the mmap_sem might be waiting in
6965 * waitq. So we cancel all extra charges, wake up all waiters,
6966 * and retry. Because we cancel precharges, we might not be able
6967 * to move enough charges, but moving charge is a best-effort
6968 * feature anyway, so it wouldn't be a big problem.
6969 */
6970 __mem_cgroup_clear_mc();
6971 cond_resched();
6972 goto retry;
6973 }
4ffef5fe
DN
6974 for (vma = mm->mmap; vma; vma = vma->vm_next) {
6975 int ret;
6976 struct mm_walk mem_cgroup_move_charge_walk = {
6977 .pmd_entry = mem_cgroup_move_charge_pte_range,
6978 .mm = mm,
6979 .private = vma,
6980 };
6981 if (is_vm_hugetlb_page(vma))
6982 continue;
4ffef5fe
DN
6983 ret = walk_page_range(vma->vm_start, vma->vm_end,
6984 &mem_cgroup_move_charge_walk);
6985 if (ret)
6986 /*
6987 * means we have consumed all precharges and failed in
6988 * doing additional charge. Just abandon here.
6989 */
6990 break;
6991 }
dfe076b0 6992 up_read(&mm->mmap_sem);
7dc74be0
DN
6993}
6994
eb95419b 6995static void mem_cgroup_move_task(struct cgroup_subsys_state *css,
761b3ef5 6996 struct cgroup_taskset *tset)
67e465a7 6997{
2f7ee569 6998 struct task_struct *p = cgroup_taskset_first(tset);
a433658c 6999 struct mm_struct *mm = get_task_mm(p);
dfe076b0 7000
dfe076b0 7001 if (mm) {
a433658c
KM
7002 if (mc.to)
7003 mem_cgroup_move_charge(mm);
dfe076b0
DN
7004 mmput(mm);
7005 }
a433658c
KM
7006 if (mc.to)
7007 mem_cgroup_clear_mc();
67e465a7 7008}
5cfb80a7 7009#else /* !CONFIG_MMU */
eb95419b 7010static int mem_cgroup_can_attach(struct cgroup_subsys_state *css,
761b3ef5 7011 struct cgroup_taskset *tset)
5cfb80a7
DN
7012{
7013 return 0;
7014}
eb95419b 7015static void mem_cgroup_cancel_attach(struct cgroup_subsys_state *css,
761b3ef5 7016 struct cgroup_taskset *tset)
5cfb80a7
DN
7017{
7018}
eb95419b 7019static void mem_cgroup_move_task(struct cgroup_subsys_state *css,
761b3ef5 7020 struct cgroup_taskset *tset)
5cfb80a7
DN
7021{
7022}
7023#endif
67e465a7 7024
f00baae7
TH
7025/*
7026 * Cgroup retains root cgroups across [un]mount cycles making it necessary
aa6ec29b
TH
7027 * to verify whether we're attached to the default hierarchy on each mount
7028 * attempt.
f00baae7 7029 */
eb95419b 7030static void mem_cgroup_bind(struct cgroup_subsys_state *root_css)
f00baae7
TH
7031{
7032 /*
aa6ec29b 7033 * use_hierarchy is forced on the default hierarchy. cgroup core
f00baae7
TH
7034 * guarantees that @root doesn't have any children, so turning it
7035 * on for the root memcg is enough.
7036 */
aa6ec29b 7037 if (cgroup_on_dfl(root_css->cgroup))
eb95419b 7038 mem_cgroup_from_css(root_css)->use_hierarchy = true;
f00baae7
TH
7039}
7040
073219e9 7041struct cgroup_subsys memory_cgrp_subsys = {
92fb9748 7042 .css_alloc = mem_cgroup_css_alloc,
d142e3e6 7043 .css_online = mem_cgroup_css_online,
92fb9748
TH
7044 .css_offline = mem_cgroup_css_offline,
7045 .css_free = mem_cgroup_css_free,
1ced953b 7046 .css_reset = mem_cgroup_css_reset,
7dc74be0
DN
7047 .can_attach = mem_cgroup_can_attach,
7048 .cancel_attach = mem_cgroup_cancel_attach,
67e465a7 7049 .attach = mem_cgroup_move_task,
f00baae7 7050 .bind = mem_cgroup_bind,
6bc10349 7051 .base_cftypes = mem_cgroup_files,
6d12e2d8 7052 .early_init = 0,
8cdea7c0 7053};
c077719b 7054
c255a458 7055#ifdef CONFIG_MEMCG_SWAP
a42c390c
MH
7056static int __init enable_swap_account(char *s)
7057{
a2c8990a 7058 if (!strcmp(s, "1"))
a42c390c 7059 really_do_swap_account = 1;
a2c8990a 7060 else if (!strcmp(s, "0"))
a42c390c
MH
7061 really_do_swap_account = 0;
7062 return 1;
7063}
a2c8990a 7064__setup("swapaccount=", enable_swap_account);
c077719b 7065
2d11085e
MH
7066static void __init memsw_file_init(void)
7067{
073219e9 7068 WARN_ON(cgroup_add_cftypes(&memory_cgrp_subsys, memsw_cgroup_files));
6acc8b02
MH
7069}
7070
7071static void __init enable_swap_cgroup(void)
7072{
7073 if (!mem_cgroup_disabled() && really_do_swap_account) {
7074 do_swap_account = 1;
7075 memsw_file_init();
7076 }
2d11085e 7077}
6acc8b02 7078
2d11085e 7079#else
6acc8b02 7080static void __init enable_swap_cgroup(void)
2d11085e
MH
7081{
7082}
c077719b 7083#endif
2d11085e
MH
7084
7085/*
1081312f
MH
7086 * subsys_initcall() for memory controller.
7087 *
7088 * Some parts like hotcpu_notifier() have to be initialized from this context
7089 * because of lock dependencies (cgroup_lock -> cpu hotplug) but basically
7090 * everything that doesn't depend on a specific mem_cgroup structure should
7091 * be initialized from here.
2d11085e
MH
7092 */
7093static int __init mem_cgroup_init(void)
7094{
7095 hotcpu_notifier(memcg_cpu_hotplug_callback, 0);
6acc8b02 7096 enable_swap_cgroup();
bb4cc1a8 7097 mem_cgroup_soft_limit_tree_init();
e4777496 7098 memcg_stock_init();
2d11085e
MH
7099 return 0;
7100}
7101subsys_initcall(mem_cgroup_init);