]>
Commit | Line | Data |
---|---|---|
1 | /* memcontrol.c - Memory Controller | |
2 | * | |
3 | * Copyright IBM Corporation, 2007 | |
4 | * Author Balbir Singh <balbir@linux.vnet.ibm.com> | |
5 | * | |
6 | * Copyright 2007 OpenVZ SWsoft Inc | |
7 | * Author: Pavel Emelianov <xemul@openvz.org> | |
8 | * | |
9 | * Memory thresholds | |
10 | * Copyright (C) 2009 Nokia Corporation | |
11 | * Author: Kirill A. Shutemov | |
12 | * | |
13 | * Kernel Memory Controller | |
14 | * Copyright (C) 2012 Parallels Inc. and Google Inc. | |
15 | * Authors: Glauber Costa and Suleiman Souhlal | |
16 | * | |
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> | |
31 | #include <linux/mm.h> | |
32 | #include <linux/hugetlb.h> | |
33 | #include <linux/pagemap.h> | |
34 | #include <linux/smp.h> | |
35 | #include <linux/page-flags.h> | |
36 | #include <linux/backing-dev.h> | |
37 | #include <linux/bit_spinlock.h> | |
38 | #include <linux/rcupdate.h> | |
39 | #include <linux/limits.h> | |
40 | #include <linux/export.h> | |
41 | #include <linux/mutex.h> | |
42 | #include <linux/rbtree.h> | |
43 | #include <linux/slab.h> | |
44 | #include <linux/swap.h> | |
45 | #include <linux/swapops.h> | |
46 | #include <linux/spinlock.h> | |
47 | #include <linux/eventfd.h> | |
48 | #include <linux/poll.h> | |
49 | #include <linux/sort.h> | |
50 | #include <linux/fs.h> | |
51 | #include <linux/seq_file.h> | |
52 | #include <linux/vmpressure.h> | |
53 | #include <linux/mm_inline.h> | |
54 | #include <linux/page_cgroup.h> | |
55 | #include <linux/cpu.h> | |
56 | #include <linux/oom.h> | |
57 | #include <linux/lockdep.h> | |
58 | #include <linux/file.h> | |
59 | #include "internal.h" | |
60 | #include <net/sock.h> | |
61 | #include <net/ip.h> | |
62 | #include <net/tcp_memcontrol.h> | |
63 | #include "slab.h" | |
64 | ||
65 | #include <asm/uaccess.h> | |
66 | ||
67 | #include <trace/events/vmscan.h> | |
68 | ||
69 | struct cgroup_subsys memory_cgrp_subsys __read_mostly; | |
70 | EXPORT_SYMBOL(memory_cgrp_subsys); | |
71 | ||
72 | #define MEM_CGROUP_RECLAIM_RETRIES 5 | |
73 | static struct mem_cgroup *root_mem_cgroup __read_mostly; | |
74 | ||
75 | #ifdef CONFIG_MEMCG_SWAP | |
76 | /* Turned on only when memory cgroup is enabled && really_do_swap_account = 1 */ | |
77 | int do_swap_account __read_mostly; | |
78 | ||
79 | /* for remember boot option*/ | |
80 | #ifdef CONFIG_MEMCG_SWAP_ENABLED | |
81 | static int really_do_swap_account __initdata = 1; | |
82 | #else | |
83 | static int really_do_swap_account __initdata = 0; | |
84 | #endif | |
85 | ||
86 | #else | |
87 | #define do_swap_account 0 | |
88 | #endif | |
89 | ||
90 | ||
91 | static const char * const mem_cgroup_stat_names[] = { | |
92 | "cache", | |
93 | "rss", | |
94 | "rss_huge", | |
95 | "mapped_file", | |
96 | "writeback", | |
97 | "swap", | |
98 | }; | |
99 | ||
100 | enum mem_cgroup_events_index { | |
101 | MEM_CGROUP_EVENTS_PGPGIN, /* # of pages paged in */ | |
102 | MEM_CGROUP_EVENTS_PGPGOUT, /* # of pages paged out */ | |
103 | MEM_CGROUP_EVENTS_PGFAULT, /* # of page-faults */ | |
104 | MEM_CGROUP_EVENTS_PGMAJFAULT, /* # of major page-faults */ | |
105 | MEM_CGROUP_EVENTS_NSTATS, | |
106 | }; | |
107 | ||
108 | static const char * const mem_cgroup_events_names[] = { | |
109 | "pgpgin", | |
110 | "pgpgout", | |
111 | "pgfault", | |
112 | "pgmajfault", | |
113 | }; | |
114 | ||
115 | static const char * const mem_cgroup_lru_names[] = { | |
116 | "inactive_anon", | |
117 | "active_anon", | |
118 | "inactive_file", | |
119 | "active_file", | |
120 | "unevictable", | |
121 | }; | |
122 | ||
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 | */ | |
129 | enum mem_cgroup_events_target { | |
130 | MEM_CGROUP_TARGET_THRESH, | |
131 | MEM_CGROUP_TARGET_SOFTLIMIT, | |
132 | MEM_CGROUP_TARGET_NUMAINFO, | |
133 | MEM_CGROUP_NTARGETS, | |
134 | }; | |
135 | #define THRESHOLDS_EVENTS_TARGET 128 | |
136 | #define SOFTLIMIT_EVENTS_TARGET 1024 | |
137 | #define NUMAINFO_EVENTS_TARGET 1024 | |
138 | ||
139 | struct mem_cgroup_stat_cpu { | |
140 | long count[MEM_CGROUP_STAT_NSTATS]; | |
141 | unsigned long events[MEM_CGROUP_EVENTS_NSTATS]; | |
142 | unsigned long nr_page_events; | |
143 | unsigned long targets[MEM_CGROUP_NTARGETS]; | |
144 | }; | |
145 | ||
146 | struct mem_cgroup_reclaim_iter { | |
147 | /* | |
148 | * last scanned hierarchy member. Valid only if last_dead_count | |
149 | * matches memcg->dead_count of the hierarchy root group. | |
150 | */ | |
151 | struct mem_cgroup *last_visited; | |
152 | int last_dead_count; | |
153 | ||
154 | /* scan generation, increased every round-trip */ | |
155 | unsigned int generation; | |
156 | }; | |
157 | ||
158 | /* | |
159 | * per-zone information in memory controller. | |
160 | */ | |
161 | struct mem_cgroup_per_zone { | |
162 | struct lruvec lruvec; | |
163 | unsigned long lru_size[NR_LRU_LISTS]; | |
164 | ||
165 | struct mem_cgroup_reclaim_iter reclaim_iter[DEF_PRIORITY + 1]; | |
166 | ||
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; | |
171 | struct mem_cgroup *memcg; /* Back pointer, we cannot */ | |
172 | /* use container_of */ | |
173 | }; | |
174 | ||
175 | struct mem_cgroup_per_node { | |
176 | struct mem_cgroup_per_zone zoneinfo[MAX_NR_ZONES]; | |
177 | }; | |
178 | ||
179 | /* | |
180 | * Cgroups above their limits are maintained in a RB-Tree, independent of | |
181 | * their hierarchy representation | |
182 | */ | |
183 | ||
184 | struct mem_cgroup_tree_per_zone { | |
185 | struct rb_root rb_root; | |
186 | spinlock_t lock; | |
187 | }; | |
188 | ||
189 | struct mem_cgroup_tree_per_node { | |
190 | struct mem_cgroup_tree_per_zone rb_tree_per_zone[MAX_NR_ZONES]; | |
191 | }; | |
192 | ||
193 | struct mem_cgroup_tree { | |
194 | struct mem_cgroup_tree_per_node *rb_tree_per_node[MAX_NUMNODES]; | |
195 | }; | |
196 | ||
197 | static struct mem_cgroup_tree soft_limit_tree __read_mostly; | |
198 | ||
199 | struct mem_cgroup_threshold { | |
200 | struct eventfd_ctx *eventfd; | |
201 | u64 threshold; | |
202 | }; | |
203 | ||
204 | /* For threshold */ | |
205 | struct mem_cgroup_threshold_ary { | |
206 | /* An array index points to threshold just below or equal to usage. */ | |
207 | int current_threshold; | |
208 | /* Size of entries[] */ | |
209 | unsigned int size; | |
210 | /* Array of thresholds */ | |
211 | struct mem_cgroup_threshold entries[0]; | |
212 | }; | |
213 | ||
214 | struct 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 | ||
225 | /* for OOM */ | |
226 | struct mem_cgroup_eventfd_list { | |
227 | struct list_head list; | |
228 | struct eventfd_ctx *eventfd; | |
229 | }; | |
230 | ||
231 | /* | |
232 | * cgroup_event represents events which userspace want to receive. | |
233 | */ | |
234 | struct mem_cgroup_event { | |
235 | /* | |
236 | * memcg which the event belongs to. | |
237 | */ | |
238 | struct mem_cgroup *memcg; | |
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; | |
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 | */ | |
252 | int (*register_event)(struct mem_cgroup *memcg, | |
253 | struct eventfd_ctx *eventfd, const char *args); | |
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 | */ | |
259 | void (*unregister_event)(struct mem_cgroup *memcg, | |
260 | struct eventfd_ctx *eventfd); | |
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 | ||
271 | static void mem_cgroup_threshold(struct mem_cgroup *memcg); | |
272 | static void mem_cgroup_oom_notify(struct mem_cgroup *memcg); | |
273 | ||
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 | |
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. | |
284 | */ | |
285 | struct mem_cgroup { | |
286 | struct cgroup_subsys_state css; | |
287 | /* | |
288 | * the counter to account for memory usage | |
289 | */ | |
290 | struct res_counter res; | |
291 | ||
292 | /* vmpressure notifications */ | |
293 | struct vmpressure vmpressure; | |
294 | ||
295 | /* | |
296 | * the counter to account for mem+swap usage. | |
297 | */ | |
298 | struct res_counter memsw; | |
299 | ||
300 | /* | |
301 | * the counter to account for kernel memory usage. | |
302 | */ | |
303 | struct res_counter kmem; | |
304 | /* | |
305 | * Should the accounting and control be hierarchical, per subtree? | |
306 | */ | |
307 | bool use_hierarchy; | |
308 | unsigned long kmem_account_flags; /* See KMEM_ACCOUNTED_*, below */ | |
309 | ||
310 | bool oom_lock; | |
311 | atomic_t under_oom; | |
312 | atomic_t oom_wakeups; | |
313 | ||
314 | int swappiness; | |
315 | /* OOM-Killer disable */ | |
316 | int oom_kill_disable; | |
317 | ||
318 | /* set when res.limit == memsw.limit */ | |
319 | bool memsw_is_minimum; | |
320 | ||
321 | /* protect arrays of thresholds */ | |
322 | struct mutex thresholds_lock; | |
323 | ||
324 | /* thresholds for memory usage. RCU-protected */ | |
325 | struct mem_cgroup_thresholds thresholds; | |
326 | ||
327 | /* thresholds for mem+swap usage. RCU-protected */ | |
328 | struct mem_cgroup_thresholds memsw_thresholds; | |
329 | ||
330 | /* For oom notifier event fd */ | |
331 | struct list_head oom_notify; | |
332 | ||
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 | */ | |
337 | unsigned long move_charge_at_immigrate; | |
338 | /* | |
339 | * set > 0 if pages under this cgroup are moving to other cgroup. | |
340 | */ | |
341 | atomic_t moving_account; | |
342 | /* taken only while moving_account > 0 */ | |
343 | spinlock_t move_lock; | |
344 | /* | |
345 | * percpu counter. | |
346 | */ | |
347 | struct mem_cgroup_stat_cpu __percpu *stat; | |
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; | |
354 | ||
355 | atomic_t dead_count; | |
356 | #if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_INET) | |
357 | struct cg_proto tcp_mem; | |
358 | #endif | |
359 | #if defined(CONFIG_MEMCG_KMEM) | |
360 | /* analogous to slab_common's slab_caches list. per-memcg */ | |
361 | struct list_head memcg_slab_caches; | |
362 | /* Not a spinlock, we can take a lot of time walking the list */ | |
363 | struct mutex slab_caches_mutex; | |
364 | /* Index in the kmem_cache->memcg_params->memcg_caches array */ | |
365 | int kmemcg_id; | |
366 | #endif | |
367 | ||
368 | int last_scanned_node; | |
369 | #if MAX_NUMNODES > 1 | |
370 | nodemask_t scan_nodes; | |
371 | atomic_t numainfo_events; | |
372 | atomic_t numainfo_updating; | |
373 | #endif | |
374 | ||
375 | /* List of events which userspace want to receive */ | |
376 | struct list_head event_list; | |
377 | spinlock_t event_list_lock; | |
378 | ||
379 | struct mem_cgroup_per_node *nodeinfo[0]; | |
380 | /* WARNING: nodeinfo must be the last member here */ | |
381 | }; | |
382 | ||
383 | /* internal only representation about the status of kmem accounting. */ | |
384 | enum { | |
385 | KMEM_ACCOUNTED_ACTIVE, /* accounted by this cgroup itself */ | |
386 | KMEM_ACCOUNTED_DEAD, /* dead memcg with pending kmem charges */ | |
387 | }; | |
388 | ||
389 | #ifdef CONFIG_MEMCG_KMEM | |
390 | static inline void memcg_kmem_set_active(struct mem_cgroup *memcg) | |
391 | { | |
392 | set_bit(KMEM_ACCOUNTED_ACTIVE, &memcg->kmem_account_flags); | |
393 | } | |
394 | ||
395 | static bool memcg_kmem_is_active(struct mem_cgroup *memcg) | |
396 | { | |
397 | return test_bit(KMEM_ACCOUNTED_ACTIVE, &memcg->kmem_account_flags); | |
398 | } | |
399 | ||
400 | static void memcg_kmem_mark_dead(struct mem_cgroup *memcg) | |
401 | { | |
402 | /* | |
403 | * Our caller must use css_get() first, because memcg_uncharge_kmem() | |
404 | * will call css_put() if it sees the memcg is dead. | |
405 | */ | |
406 | smp_wmb(); | |
407 | if (test_bit(KMEM_ACCOUNTED_ACTIVE, &memcg->kmem_account_flags)) | |
408 | set_bit(KMEM_ACCOUNTED_DEAD, &memcg->kmem_account_flags); | |
409 | } | |
410 | ||
411 | static bool memcg_kmem_test_and_clear_dead(struct mem_cgroup *memcg) | |
412 | { | |
413 | return test_and_clear_bit(KMEM_ACCOUNTED_DEAD, | |
414 | &memcg->kmem_account_flags); | |
415 | } | |
416 | #endif | |
417 | ||
418 | /* Stuffs for move charges at task migration. */ | |
419 | /* | |
420 | * Types of charges to be moved. "move_charge_at_immitgrate" and | |
421 | * "immigrate_flags" are treated as a left-shifted bitmap of these types. | |
422 | */ | |
423 | enum move_type { | |
424 | MOVE_CHARGE_TYPE_ANON, /* private anonymous page and swap of it */ | |
425 | MOVE_CHARGE_TYPE_FILE, /* file page(including tmpfs) and swap of it */ | |
426 | NR_MOVE_TYPE, | |
427 | }; | |
428 | ||
429 | /* "mc" and its members are protected by cgroup_mutex */ | |
430 | static struct move_charge_struct { | |
431 | spinlock_t lock; /* for from, to */ | |
432 | struct mem_cgroup *from; | |
433 | struct mem_cgroup *to; | |
434 | unsigned long immigrate_flags; | |
435 | unsigned long precharge; | |
436 | unsigned long moved_charge; | |
437 | unsigned long moved_swap; | |
438 | struct task_struct *moving_task; /* a task moving charges */ | |
439 | wait_queue_head_t waitq; /* a waitq for other context */ | |
440 | } mc = { | |
441 | .lock = __SPIN_LOCK_UNLOCKED(mc.lock), | |
442 | .waitq = __WAIT_QUEUE_HEAD_INITIALIZER(mc.waitq), | |
443 | }; | |
444 | ||
445 | static bool move_anon(void) | |
446 | { | |
447 | return test_bit(MOVE_CHARGE_TYPE_ANON, &mc.immigrate_flags); | |
448 | } | |
449 | ||
450 | static bool move_file(void) | |
451 | { | |
452 | return test_bit(MOVE_CHARGE_TYPE_FILE, &mc.immigrate_flags); | |
453 | } | |
454 | ||
455 | /* | |
456 | * Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft | |
457 | * limit reclaim to prevent infinite loops, if they ever occur. | |
458 | */ | |
459 | #define MEM_CGROUP_MAX_RECLAIM_LOOPS 100 | |
460 | #define MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS 2 | |
461 | ||
462 | enum charge_type { | |
463 | MEM_CGROUP_CHARGE_TYPE_CACHE = 0, | |
464 | MEM_CGROUP_CHARGE_TYPE_ANON, | |
465 | MEM_CGROUP_CHARGE_TYPE_SWAPOUT, /* for accounting swapcache */ | |
466 | MEM_CGROUP_CHARGE_TYPE_DROP, /* a page was unused swap cache */ | |
467 | NR_CHARGE_TYPE, | |
468 | }; | |
469 | ||
470 | /* for encoding cft->private value on file */ | |
471 | enum res_type { | |
472 | _MEM, | |
473 | _MEMSWAP, | |
474 | _OOM_TYPE, | |
475 | _KMEM, | |
476 | }; | |
477 | ||
478 | #define MEMFILE_PRIVATE(x, val) ((x) << 16 | (val)) | |
479 | #define MEMFILE_TYPE(val) ((val) >> 16 & 0xffff) | |
480 | #define MEMFILE_ATTR(val) ((val) & 0xffff) | |
481 | /* Used for OOM nofiier */ | |
482 | #define OOM_CONTROL (0) | |
483 | ||
484 | /* | |
485 | * Reclaim flags for mem_cgroup_hierarchical_reclaim | |
486 | */ | |
487 | #define MEM_CGROUP_RECLAIM_NOSWAP_BIT 0x0 | |
488 | #define MEM_CGROUP_RECLAIM_NOSWAP (1 << MEM_CGROUP_RECLAIM_NOSWAP_BIT) | |
489 | #define MEM_CGROUP_RECLAIM_SHRINK_BIT 0x1 | |
490 | #define MEM_CGROUP_RECLAIM_SHRINK (1 << MEM_CGROUP_RECLAIM_SHRINK_BIT) | |
491 | ||
492 | /* | |
493 | * The memcg_create_mutex will be held whenever a new cgroup is created. | |
494 | * As a consequence, any change that needs to protect against new child cgroups | |
495 | * appearing has to hold it as well. | |
496 | */ | |
497 | static DEFINE_MUTEX(memcg_create_mutex); | |
498 | ||
499 | struct mem_cgroup *mem_cgroup_from_css(struct cgroup_subsys_state *s) | |
500 | { | |
501 | return s ? container_of(s, struct mem_cgroup, css) : NULL; | |
502 | } | |
503 | ||
504 | /* Some nice accessors for the vmpressure. */ | |
505 | struct vmpressure *memcg_to_vmpressure(struct mem_cgroup *memcg) | |
506 | { | |
507 | if (!memcg) | |
508 | memcg = root_mem_cgroup; | |
509 | return &memcg->vmpressure; | |
510 | } | |
511 | ||
512 | struct cgroup_subsys_state *vmpressure_to_css(struct vmpressure *vmpr) | |
513 | { | |
514 | return &container_of(vmpr, struct mem_cgroup, vmpressure)->css; | |
515 | } | |
516 | ||
517 | static inline bool mem_cgroup_is_root(struct mem_cgroup *memcg) | |
518 | { | |
519 | return (memcg == root_mem_cgroup); | |
520 | } | |
521 | ||
522 | /* | |
523 | * We restrict the id in the range of [1, 65535], so it can fit into | |
524 | * an unsigned short. | |
525 | */ | |
526 | #define MEM_CGROUP_ID_MAX USHRT_MAX | |
527 | ||
528 | static inline unsigned short mem_cgroup_id(struct mem_cgroup *memcg) | |
529 | { | |
530 | /* | |
531 | * The ID of the root cgroup is 0, but memcg treat 0 as an | |
532 | * invalid ID, so we return (cgroup_id + 1). | |
533 | */ | |
534 | return memcg->css.cgroup->id + 1; | |
535 | } | |
536 | ||
537 | static inline struct mem_cgroup *mem_cgroup_from_id(unsigned short id) | |
538 | { | |
539 | struct cgroup_subsys_state *css; | |
540 | ||
541 | css = css_from_id(id - 1, &memory_cgrp_subsys); | |
542 | return mem_cgroup_from_css(css); | |
543 | } | |
544 | ||
545 | /* Writing them here to avoid exposing memcg's inner layout */ | |
546 | #if defined(CONFIG_INET) && defined(CONFIG_MEMCG_KMEM) | |
547 | ||
548 | void sock_update_memcg(struct sock *sk) | |
549 | { | |
550 | if (mem_cgroup_sockets_enabled) { | |
551 | struct mem_cgroup *memcg; | |
552 | struct cg_proto *cg_proto; | |
553 | ||
554 | BUG_ON(!sk->sk_prot->proto_cgroup); | |
555 | ||
556 | /* Socket cloning can throw us here with sk_cgrp already | |
557 | * filled. It won't however, necessarily happen from | |
558 | * process context. So the test for root memcg given | |
559 | * the current task's memcg won't help us in this case. | |
560 | * | |
561 | * Respecting the original socket's memcg is a better | |
562 | * decision in this case. | |
563 | */ | |
564 | if (sk->sk_cgrp) { | |
565 | BUG_ON(mem_cgroup_is_root(sk->sk_cgrp->memcg)); | |
566 | css_get(&sk->sk_cgrp->memcg->css); | |
567 | return; | |
568 | } | |
569 | ||
570 | rcu_read_lock(); | |
571 | memcg = mem_cgroup_from_task(current); | |
572 | cg_proto = sk->sk_prot->proto_cgroup(memcg); | |
573 | if (!mem_cgroup_is_root(memcg) && | |
574 | memcg_proto_active(cg_proto) && css_tryget(&memcg->css)) { | |
575 | sk->sk_cgrp = cg_proto; | |
576 | } | |
577 | rcu_read_unlock(); | |
578 | } | |
579 | } | |
580 | EXPORT_SYMBOL(sock_update_memcg); | |
581 | ||
582 | void sock_release_memcg(struct sock *sk) | |
583 | { | |
584 | if (mem_cgroup_sockets_enabled && sk->sk_cgrp) { | |
585 | struct mem_cgroup *memcg; | |
586 | WARN_ON(!sk->sk_cgrp->memcg); | |
587 | memcg = sk->sk_cgrp->memcg; | |
588 | css_put(&sk->sk_cgrp->memcg->css); | |
589 | } | |
590 | } | |
591 | ||
592 | struct cg_proto *tcp_proto_cgroup(struct mem_cgroup *memcg) | |
593 | { | |
594 | if (!memcg || mem_cgroup_is_root(memcg)) | |
595 | return NULL; | |
596 | ||
597 | return &memcg->tcp_mem; | |
598 | } | |
599 | EXPORT_SYMBOL(tcp_proto_cgroup); | |
600 | ||
601 | static void disarm_sock_keys(struct mem_cgroup *memcg) | |
602 | { | |
603 | if (!memcg_proto_activated(&memcg->tcp_mem)) | |
604 | return; | |
605 | static_key_slow_dec(&memcg_socket_limit_enabled); | |
606 | } | |
607 | #else | |
608 | static void disarm_sock_keys(struct mem_cgroup *memcg) | |
609 | { | |
610 | } | |
611 | #endif | |
612 | ||
613 | #ifdef CONFIG_MEMCG_KMEM | |
614 | /* | |
615 | * This will be the memcg's index in each cache's ->memcg_params->memcg_caches. | |
616 | * The main reason for not using cgroup id for this: | |
617 | * this works better in sparse environments, where we have a lot of memcgs, | |
618 | * but only a few kmem-limited. Or also, if we have, for instance, 200 | |
619 | * memcgs, and none but the 200th is kmem-limited, we'd have to have a | |
620 | * 200 entry array for that. | |
621 | * | |
622 | * The current size of the caches array is stored in | |
623 | * memcg_limited_groups_array_size. It will double each time we have to | |
624 | * increase it. | |
625 | */ | |
626 | static DEFINE_IDA(kmem_limited_groups); | |
627 | int memcg_limited_groups_array_size; | |
628 | ||
629 | /* | |
630 | * MIN_SIZE is different than 1, because we would like to avoid going through | |
631 | * the alloc/free process all the time. In a small machine, 4 kmem-limited | |
632 | * cgroups is a reasonable guess. In the future, it could be a parameter or | |
633 | * tunable, but that is strictly not necessary. | |
634 | * | |
635 | * MAX_SIZE should be as large as the number of cgrp_ids. Ideally, we could get | |
636 | * this constant directly from cgroup, but it is understandable that this is | |
637 | * better kept as an internal representation in cgroup.c. In any case, the | |
638 | * cgrp_id space is not getting any smaller, and we don't have to necessarily | |
639 | * increase ours as well if it increases. | |
640 | */ | |
641 | #define MEMCG_CACHES_MIN_SIZE 4 | |
642 | #define MEMCG_CACHES_MAX_SIZE MEM_CGROUP_ID_MAX | |
643 | ||
644 | /* | |
645 | * A lot of the calls to the cache allocation functions are expected to be | |
646 | * inlined by the compiler. Since the calls to memcg_kmem_get_cache are | |
647 | * conditional to this static branch, we'll have to allow modules that does | |
648 | * kmem_cache_alloc and the such to see this symbol as well | |
649 | */ | |
650 | struct static_key memcg_kmem_enabled_key; | |
651 | EXPORT_SYMBOL(memcg_kmem_enabled_key); | |
652 | ||
653 | static void disarm_kmem_keys(struct mem_cgroup *memcg) | |
654 | { | |
655 | if (memcg_kmem_is_active(memcg)) { | |
656 | static_key_slow_dec(&memcg_kmem_enabled_key); | |
657 | ida_simple_remove(&kmem_limited_groups, memcg->kmemcg_id); | |
658 | } | |
659 | /* | |
660 | * This check can't live in kmem destruction function, | |
661 | * since the charges will outlive the cgroup | |
662 | */ | |
663 | WARN_ON(res_counter_read_u64(&memcg->kmem, RES_USAGE) != 0); | |
664 | } | |
665 | #else | |
666 | static void disarm_kmem_keys(struct mem_cgroup *memcg) | |
667 | { | |
668 | } | |
669 | #endif /* CONFIG_MEMCG_KMEM */ | |
670 | ||
671 | static void disarm_static_keys(struct mem_cgroup *memcg) | |
672 | { | |
673 | disarm_sock_keys(memcg); | |
674 | disarm_kmem_keys(memcg); | |
675 | } | |
676 | ||
677 | static void drain_all_stock_async(struct mem_cgroup *memcg); | |
678 | ||
679 | static struct mem_cgroup_per_zone * | |
680 | mem_cgroup_zoneinfo(struct mem_cgroup *memcg, int nid, int zid) | |
681 | { | |
682 | VM_BUG_ON((unsigned)nid >= nr_node_ids); | |
683 | return &memcg->nodeinfo[nid]->zoneinfo[zid]; | |
684 | } | |
685 | ||
686 | struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *memcg) | |
687 | { | |
688 | return &memcg->css; | |
689 | } | |
690 | ||
691 | static struct mem_cgroup_per_zone * | |
692 | page_cgroup_zoneinfo(struct mem_cgroup *memcg, struct page *page) | |
693 | { | |
694 | int nid = page_to_nid(page); | |
695 | int zid = page_zonenum(page); | |
696 | ||
697 | return mem_cgroup_zoneinfo(memcg, nid, zid); | |
698 | } | |
699 | ||
700 | static struct mem_cgroup_tree_per_zone * | |
701 | soft_limit_tree_node_zone(int nid, int zid) | |
702 | { | |
703 | return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid]; | |
704 | } | |
705 | ||
706 | static struct mem_cgroup_tree_per_zone * | |
707 | soft_limit_tree_from_page(struct page *page) | |
708 | { | |
709 | int nid = page_to_nid(page); | |
710 | int zid = page_zonenum(page); | |
711 | ||
712 | return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid]; | |
713 | } | |
714 | ||
715 | static void | |
716 | __mem_cgroup_insert_exceeded(struct mem_cgroup *memcg, | |
717 | struct mem_cgroup_per_zone *mz, | |
718 | struct mem_cgroup_tree_per_zone *mctz, | |
719 | unsigned long long new_usage_in_excess) | |
720 | { | |
721 | struct rb_node **p = &mctz->rb_root.rb_node; | |
722 | struct rb_node *parent = NULL; | |
723 | struct mem_cgroup_per_zone *mz_node; | |
724 | ||
725 | if (mz->on_tree) | |
726 | return; | |
727 | ||
728 | mz->usage_in_excess = new_usage_in_excess; | |
729 | if (!mz->usage_in_excess) | |
730 | return; | |
731 | while (*p) { | |
732 | parent = *p; | |
733 | mz_node = rb_entry(parent, struct mem_cgroup_per_zone, | |
734 | tree_node); | |
735 | if (mz->usage_in_excess < mz_node->usage_in_excess) | |
736 | p = &(*p)->rb_left; | |
737 | /* | |
738 | * We can't avoid mem cgroups that are over their soft | |
739 | * limit by the same amount | |
740 | */ | |
741 | else if (mz->usage_in_excess >= mz_node->usage_in_excess) | |
742 | p = &(*p)->rb_right; | |
743 | } | |
744 | rb_link_node(&mz->tree_node, parent, p); | |
745 | rb_insert_color(&mz->tree_node, &mctz->rb_root); | |
746 | mz->on_tree = true; | |
747 | } | |
748 | ||
749 | static void | |
750 | __mem_cgroup_remove_exceeded(struct mem_cgroup *memcg, | |
751 | struct mem_cgroup_per_zone *mz, | |
752 | struct mem_cgroup_tree_per_zone *mctz) | |
753 | { | |
754 | if (!mz->on_tree) | |
755 | return; | |
756 | rb_erase(&mz->tree_node, &mctz->rb_root); | |
757 | mz->on_tree = false; | |
758 | } | |
759 | ||
760 | static void | |
761 | mem_cgroup_remove_exceeded(struct mem_cgroup *memcg, | |
762 | struct mem_cgroup_per_zone *mz, | |
763 | struct mem_cgroup_tree_per_zone *mctz) | |
764 | { | |
765 | spin_lock(&mctz->lock); | |
766 | __mem_cgroup_remove_exceeded(memcg, mz, mctz); | |
767 | spin_unlock(&mctz->lock); | |
768 | } | |
769 | ||
770 | ||
771 | static void mem_cgroup_update_tree(struct mem_cgroup *memcg, struct page *page) | |
772 | { | |
773 | unsigned long long excess; | |
774 | struct mem_cgroup_per_zone *mz; | |
775 | struct mem_cgroup_tree_per_zone *mctz; | |
776 | int nid = page_to_nid(page); | |
777 | int zid = page_zonenum(page); | |
778 | mctz = soft_limit_tree_from_page(page); | |
779 | ||
780 | /* | |
781 | * Necessary to update all ancestors when hierarchy is used. | |
782 | * because their event counter is not touched. | |
783 | */ | |
784 | for (; memcg; memcg = parent_mem_cgroup(memcg)) { | |
785 | mz = mem_cgroup_zoneinfo(memcg, nid, zid); | |
786 | excess = res_counter_soft_limit_excess(&memcg->res); | |
787 | /* | |
788 | * We have to update the tree if mz is on RB-tree or | |
789 | * mem is over its softlimit. | |
790 | */ | |
791 | if (excess || mz->on_tree) { | |
792 | spin_lock(&mctz->lock); | |
793 | /* if on-tree, remove it */ | |
794 | if (mz->on_tree) | |
795 | __mem_cgroup_remove_exceeded(memcg, mz, mctz); | |
796 | /* | |
797 | * Insert again. mz->usage_in_excess will be updated. | |
798 | * If excess is 0, no tree ops. | |
799 | */ | |
800 | __mem_cgroup_insert_exceeded(memcg, mz, mctz, excess); | |
801 | spin_unlock(&mctz->lock); | |
802 | } | |
803 | } | |
804 | } | |
805 | ||
806 | static void mem_cgroup_remove_from_trees(struct mem_cgroup *memcg) | |
807 | { | |
808 | int node, zone; | |
809 | struct mem_cgroup_per_zone *mz; | |
810 | struct mem_cgroup_tree_per_zone *mctz; | |
811 | ||
812 | for_each_node(node) { | |
813 | for (zone = 0; zone < MAX_NR_ZONES; zone++) { | |
814 | mz = mem_cgroup_zoneinfo(memcg, node, zone); | |
815 | mctz = soft_limit_tree_node_zone(node, zone); | |
816 | mem_cgroup_remove_exceeded(memcg, mz, mctz); | |
817 | } | |
818 | } | |
819 | } | |
820 | ||
821 | static struct mem_cgroup_per_zone * | |
822 | __mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz) | |
823 | { | |
824 | struct rb_node *rightmost = NULL; | |
825 | struct mem_cgroup_per_zone *mz; | |
826 | ||
827 | retry: | |
828 | mz = NULL; | |
829 | rightmost = rb_last(&mctz->rb_root); | |
830 | if (!rightmost) | |
831 | goto done; /* Nothing to reclaim from */ | |
832 | ||
833 | mz = rb_entry(rightmost, struct mem_cgroup_per_zone, tree_node); | |
834 | /* | |
835 | * Remove the node now but someone else can add it back, | |
836 | * we will to add it back at the end of reclaim to its correct | |
837 | * position in the tree. | |
838 | */ | |
839 | __mem_cgroup_remove_exceeded(mz->memcg, mz, mctz); | |
840 | if (!res_counter_soft_limit_excess(&mz->memcg->res) || | |
841 | !css_tryget(&mz->memcg->css)) | |
842 | goto retry; | |
843 | done: | |
844 | return mz; | |
845 | } | |
846 | ||
847 | static struct mem_cgroup_per_zone * | |
848 | mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz) | |
849 | { | |
850 | struct mem_cgroup_per_zone *mz; | |
851 | ||
852 | spin_lock(&mctz->lock); | |
853 | mz = __mem_cgroup_largest_soft_limit_node(mctz); | |
854 | spin_unlock(&mctz->lock); | |
855 | return mz; | |
856 | } | |
857 | ||
858 | /* | |
859 | * Implementation Note: reading percpu statistics for memcg. | |
860 | * | |
861 | * Both of vmstat[] and percpu_counter has threshold and do periodic | |
862 | * synchronization to implement "quick" read. There are trade-off between | |
863 | * reading cost and precision of value. Then, we may have a chance to implement | |
864 | * a periodic synchronizion of counter in memcg's counter. | |
865 | * | |
866 | * But this _read() function is used for user interface now. The user accounts | |
867 | * memory usage by memory cgroup and he _always_ requires exact value because | |
868 | * he accounts memory. Even if we provide quick-and-fuzzy read, we always | |
869 | * have to visit all online cpus and make sum. So, for now, unnecessary | |
870 | * synchronization is not implemented. (just implemented for cpu hotplug) | |
871 | * | |
872 | * If there are kernel internal actions which can make use of some not-exact | |
873 | * value, and reading all cpu value can be performance bottleneck in some | |
874 | * common workload, threashold and synchonization as vmstat[] should be | |
875 | * implemented. | |
876 | */ | |
877 | static long mem_cgroup_read_stat(struct mem_cgroup *memcg, | |
878 | enum mem_cgroup_stat_index idx) | |
879 | { | |
880 | long val = 0; | |
881 | int cpu; | |
882 | ||
883 | get_online_cpus(); | |
884 | for_each_online_cpu(cpu) | |
885 | val += per_cpu(memcg->stat->count[idx], cpu); | |
886 | #ifdef CONFIG_HOTPLUG_CPU | |
887 | spin_lock(&memcg->pcp_counter_lock); | |
888 | val += memcg->nocpu_base.count[idx]; | |
889 | spin_unlock(&memcg->pcp_counter_lock); | |
890 | #endif | |
891 | put_online_cpus(); | |
892 | return val; | |
893 | } | |
894 | ||
895 | static void mem_cgroup_swap_statistics(struct mem_cgroup *memcg, | |
896 | bool charge) | |
897 | { | |
898 | int val = (charge) ? 1 : -1; | |
899 | this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_SWAP], val); | |
900 | } | |
901 | ||
902 | static unsigned long mem_cgroup_read_events(struct mem_cgroup *memcg, | |
903 | enum mem_cgroup_events_index idx) | |
904 | { | |
905 | unsigned long val = 0; | |
906 | int cpu; | |
907 | ||
908 | get_online_cpus(); | |
909 | for_each_online_cpu(cpu) | |
910 | val += per_cpu(memcg->stat->events[idx], cpu); | |
911 | #ifdef CONFIG_HOTPLUG_CPU | |
912 | spin_lock(&memcg->pcp_counter_lock); | |
913 | val += memcg->nocpu_base.events[idx]; | |
914 | spin_unlock(&memcg->pcp_counter_lock); | |
915 | #endif | |
916 | put_online_cpus(); | |
917 | return val; | |
918 | } | |
919 | ||
920 | static void mem_cgroup_charge_statistics(struct mem_cgroup *memcg, | |
921 | struct page *page, | |
922 | bool anon, int nr_pages) | |
923 | { | |
924 | /* | |
925 | * Here, RSS means 'mapped anon' and anon's SwapCache. Shmem/tmpfs is | |
926 | * counted as CACHE even if it's on ANON LRU. | |
927 | */ | |
928 | if (anon) | |
929 | __this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_RSS], | |
930 | nr_pages); | |
931 | else | |
932 | __this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_CACHE], | |
933 | nr_pages); | |
934 | ||
935 | if (PageTransHuge(page)) | |
936 | __this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_RSS_HUGE], | |
937 | nr_pages); | |
938 | ||
939 | /* pagein of a big page is an event. So, ignore page size */ | |
940 | if (nr_pages > 0) | |
941 | __this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGPGIN]); | |
942 | else { | |
943 | __this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGPGOUT]); | |
944 | nr_pages = -nr_pages; /* for event */ | |
945 | } | |
946 | ||
947 | __this_cpu_add(memcg->stat->nr_page_events, nr_pages); | |
948 | } | |
949 | ||
950 | unsigned long | |
951 | mem_cgroup_get_lru_size(struct lruvec *lruvec, enum lru_list lru) | |
952 | { | |
953 | struct mem_cgroup_per_zone *mz; | |
954 | ||
955 | mz = container_of(lruvec, struct mem_cgroup_per_zone, lruvec); | |
956 | return mz->lru_size[lru]; | |
957 | } | |
958 | ||
959 | static unsigned long | |
960 | mem_cgroup_zone_nr_lru_pages(struct mem_cgroup *memcg, int nid, int zid, | |
961 | unsigned int lru_mask) | |
962 | { | |
963 | struct mem_cgroup_per_zone *mz; | |
964 | enum lru_list lru; | |
965 | unsigned long ret = 0; | |
966 | ||
967 | mz = mem_cgroup_zoneinfo(memcg, nid, zid); | |
968 | ||
969 | for_each_lru(lru) { | |
970 | if (BIT(lru) & lru_mask) | |
971 | ret += mz->lru_size[lru]; | |
972 | } | |
973 | return ret; | |
974 | } | |
975 | ||
976 | static unsigned long | |
977 | mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg, | |
978 | int nid, unsigned int lru_mask) | |
979 | { | |
980 | u64 total = 0; | |
981 | int zid; | |
982 | ||
983 | for (zid = 0; zid < MAX_NR_ZONES; zid++) | |
984 | total += mem_cgroup_zone_nr_lru_pages(memcg, | |
985 | nid, zid, lru_mask); | |
986 | ||
987 | return total; | |
988 | } | |
989 | ||
990 | static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup *memcg, | |
991 | unsigned int lru_mask) | |
992 | { | |
993 | int nid; | |
994 | u64 total = 0; | |
995 | ||
996 | for_each_node_state(nid, N_MEMORY) | |
997 | total += mem_cgroup_node_nr_lru_pages(memcg, nid, lru_mask); | |
998 | return total; | |
999 | } | |
1000 | ||
1001 | static bool mem_cgroup_event_ratelimit(struct mem_cgroup *memcg, | |
1002 | enum mem_cgroup_events_target target) | |
1003 | { | |
1004 | unsigned long val, next; | |
1005 | ||
1006 | val = __this_cpu_read(memcg->stat->nr_page_events); | |
1007 | next = __this_cpu_read(memcg->stat->targets[target]); | |
1008 | /* from time_after() in jiffies.h */ | |
1009 | if ((long)next - (long)val < 0) { | |
1010 | switch (target) { | |
1011 | case MEM_CGROUP_TARGET_THRESH: | |
1012 | next = val + THRESHOLDS_EVENTS_TARGET; | |
1013 | break; | |
1014 | case MEM_CGROUP_TARGET_SOFTLIMIT: | |
1015 | next = val + SOFTLIMIT_EVENTS_TARGET; | |
1016 | break; | |
1017 | case MEM_CGROUP_TARGET_NUMAINFO: | |
1018 | next = val + NUMAINFO_EVENTS_TARGET; | |
1019 | break; | |
1020 | default: | |
1021 | break; | |
1022 | } | |
1023 | __this_cpu_write(memcg->stat->targets[target], next); | |
1024 | return true; | |
1025 | } | |
1026 | return false; | |
1027 | } | |
1028 | ||
1029 | /* | |
1030 | * Check events in order. | |
1031 | * | |
1032 | */ | |
1033 | static void memcg_check_events(struct mem_cgroup *memcg, struct page *page) | |
1034 | { | |
1035 | preempt_disable(); | |
1036 | /* threshold event is triggered in finer grain than soft limit */ | |
1037 | if (unlikely(mem_cgroup_event_ratelimit(memcg, | |
1038 | MEM_CGROUP_TARGET_THRESH))) { | |
1039 | bool do_softlimit; | |
1040 | bool do_numainfo __maybe_unused; | |
1041 | ||
1042 | do_softlimit = mem_cgroup_event_ratelimit(memcg, | |
1043 | MEM_CGROUP_TARGET_SOFTLIMIT); | |
1044 | #if MAX_NUMNODES > 1 | |
1045 | do_numainfo = mem_cgroup_event_ratelimit(memcg, | |
1046 | MEM_CGROUP_TARGET_NUMAINFO); | |
1047 | #endif | |
1048 | preempt_enable(); | |
1049 | ||
1050 | mem_cgroup_threshold(memcg); | |
1051 | if (unlikely(do_softlimit)) | |
1052 | mem_cgroup_update_tree(memcg, page); | |
1053 | #if MAX_NUMNODES > 1 | |
1054 | if (unlikely(do_numainfo)) | |
1055 | atomic_inc(&memcg->numainfo_events); | |
1056 | #endif | |
1057 | } else | |
1058 | preempt_enable(); | |
1059 | } | |
1060 | ||
1061 | struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p) | |
1062 | { | |
1063 | /* | |
1064 | * mm_update_next_owner() may clear mm->owner to NULL | |
1065 | * if it races with swapoff, page migration, etc. | |
1066 | * So this can be called with p == NULL. | |
1067 | */ | |
1068 | if (unlikely(!p)) | |
1069 | return NULL; | |
1070 | ||
1071 | return mem_cgroup_from_css(task_css(p, memory_cgrp_id)); | |
1072 | } | |
1073 | ||
1074 | static struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm) | |
1075 | { | |
1076 | struct mem_cgroup *memcg = NULL; | |
1077 | ||
1078 | rcu_read_lock(); | |
1079 | do { | |
1080 | memcg = mem_cgroup_from_task(rcu_dereference(mm->owner)); | |
1081 | if (unlikely(!memcg)) | |
1082 | memcg = root_mem_cgroup; | |
1083 | } while (!css_tryget(&memcg->css)); | |
1084 | rcu_read_unlock(); | |
1085 | return memcg; | |
1086 | } | |
1087 | ||
1088 | /* | |
1089 | * Returns a next (in a pre-order walk) alive memcg (with elevated css | |
1090 | * ref. count) or NULL if the whole root's subtree has been visited. | |
1091 | * | |
1092 | * helper function to be used by mem_cgroup_iter | |
1093 | */ | |
1094 | static struct mem_cgroup *__mem_cgroup_iter_next(struct mem_cgroup *root, | |
1095 | struct mem_cgroup *last_visited) | |
1096 | { | |
1097 | struct cgroup_subsys_state *prev_css, *next_css; | |
1098 | ||
1099 | prev_css = last_visited ? &last_visited->css : NULL; | |
1100 | skip_node: | |
1101 | next_css = css_next_descendant_pre(prev_css, &root->css); | |
1102 | ||
1103 | /* | |
1104 | * Even if we found a group we have to make sure it is | |
1105 | * alive. css && !memcg means that the groups should be | |
1106 | * skipped and we should continue the tree walk. | |
1107 | * last_visited css is safe to use because it is | |
1108 | * protected by css_get and the tree walk is rcu safe. | |
1109 | * | |
1110 | * We do not take a reference on the root of the tree walk | |
1111 | * because we might race with the root removal when it would | |
1112 | * be the only node in the iterated hierarchy and mem_cgroup_iter | |
1113 | * would end up in an endless loop because it expects that at | |
1114 | * least one valid node will be returned. Root cannot disappear | |
1115 | * because caller of the iterator should hold it already so | |
1116 | * skipping css reference should be safe. | |
1117 | */ | |
1118 | if (next_css) { | |
1119 | if ((next_css == &root->css) || | |
1120 | ((next_css->flags & CSS_ONLINE) && css_tryget(next_css))) | |
1121 | return mem_cgroup_from_css(next_css); | |
1122 | ||
1123 | prev_css = next_css; | |
1124 | goto skip_node; | |
1125 | } | |
1126 | ||
1127 | return NULL; | |
1128 | } | |
1129 | ||
1130 | static void mem_cgroup_iter_invalidate(struct mem_cgroup *root) | |
1131 | { | |
1132 | /* | |
1133 | * When a group in the hierarchy below root is destroyed, the | |
1134 | * hierarchy iterator can no longer be trusted since it might | |
1135 | * have pointed to the destroyed group. Invalidate it. | |
1136 | */ | |
1137 | atomic_inc(&root->dead_count); | |
1138 | } | |
1139 | ||
1140 | static struct mem_cgroup * | |
1141 | mem_cgroup_iter_load(struct mem_cgroup_reclaim_iter *iter, | |
1142 | struct mem_cgroup *root, | |
1143 | int *sequence) | |
1144 | { | |
1145 | struct mem_cgroup *position = NULL; | |
1146 | /* | |
1147 | * A cgroup destruction happens in two stages: offlining and | |
1148 | * release. They are separated by a RCU grace period. | |
1149 | * | |
1150 | * If the iterator is valid, we may still race with an | |
1151 | * offlining. The RCU lock ensures the object won't be | |
1152 | * released, tryget will fail if we lost the race. | |
1153 | */ | |
1154 | *sequence = atomic_read(&root->dead_count); | |
1155 | if (iter->last_dead_count == *sequence) { | |
1156 | smp_rmb(); | |
1157 | position = iter->last_visited; | |
1158 | ||
1159 | /* | |
1160 | * We cannot take a reference to root because we might race | |
1161 | * with root removal and returning NULL would end up in | |
1162 | * an endless loop on the iterator user level when root | |
1163 | * would be returned all the time. | |
1164 | */ | |
1165 | if (position && position != root && | |
1166 | !css_tryget(&position->css)) | |
1167 | position = NULL; | |
1168 | } | |
1169 | return position; | |
1170 | } | |
1171 | ||
1172 | static void mem_cgroup_iter_update(struct mem_cgroup_reclaim_iter *iter, | |
1173 | struct mem_cgroup *last_visited, | |
1174 | struct mem_cgroup *new_position, | |
1175 | struct mem_cgroup *root, | |
1176 | int sequence) | |
1177 | { | |
1178 | /* root reference counting symmetric to mem_cgroup_iter_load */ | |
1179 | if (last_visited && last_visited != root) | |
1180 | css_put(&last_visited->css); | |
1181 | /* | |
1182 | * We store the sequence count from the time @last_visited was | |
1183 | * loaded successfully instead of rereading it here so that we | |
1184 | * don't lose destruction events in between. We could have | |
1185 | * raced with the destruction of @new_position after all. | |
1186 | */ | |
1187 | iter->last_visited = new_position; | |
1188 | smp_wmb(); | |
1189 | iter->last_dead_count = sequence; | |
1190 | } | |
1191 | ||
1192 | /** | |
1193 | * mem_cgroup_iter - iterate over memory cgroup hierarchy | |
1194 | * @root: hierarchy root | |
1195 | * @prev: previously returned memcg, NULL on first invocation | |
1196 | * @reclaim: cookie for shared reclaim walks, NULL for full walks | |
1197 | * | |
1198 | * Returns references to children of the hierarchy below @root, or | |
1199 | * @root itself, or %NULL after a full round-trip. | |
1200 | * | |
1201 | * Caller must pass the return value in @prev on subsequent | |
1202 | * invocations for reference counting, or use mem_cgroup_iter_break() | |
1203 | * to cancel a hierarchy walk before the round-trip is complete. | |
1204 | * | |
1205 | * Reclaimers can specify a zone and a priority level in @reclaim to | |
1206 | * divide up the memcgs in the hierarchy among all concurrent | |
1207 | * reclaimers operating on the same zone and priority. | |
1208 | */ | |
1209 | struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root, | |
1210 | struct mem_cgroup *prev, | |
1211 | struct mem_cgroup_reclaim_cookie *reclaim) | |
1212 | { | |
1213 | struct mem_cgroup *memcg = NULL; | |
1214 | struct mem_cgroup *last_visited = NULL; | |
1215 | ||
1216 | if (mem_cgroup_disabled()) | |
1217 | return NULL; | |
1218 | ||
1219 | if (!root) | |
1220 | root = root_mem_cgroup; | |
1221 | ||
1222 | if (prev && !reclaim) | |
1223 | last_visited = prev; | |
1224 | ||
1225 | if (!root->use_hierarchy && root != root_mem_cgroup) { | |
1226 | if (prev) | |
1227 | goto out_css_put; | |
1228 | return root; | |
1229 | } | |
1230 | ||
1231 | rcu_read_lock(); | |
1232 | while (!memcg) { | |
1233 | struct mem_cgroup_reclaim_iter *uninitialized_var(iter); | |
1234 | int uninitialized_var(seq); | |
1235 | ||
1236 | if (reclaim) { | |
1237 | int nid = zone_to_nid(reclaim->zone); | |
1238 | int zid = zone_idx(reclaim->zone); | |
1239 | struct mem_cgroup_per_zone *mz; | |
1240 | ||
1241 | mz = mem_cgroup_zoneinfo(root, nid, zid); | |
1242 | iter = &mz->reclaim_iter[reclaim->priority]; | |
1243 | if (prev && reclaim->generation != iter->generation) { | |
1244 | iter->last_visited = NULL; | |
1245 | goto out_unlock; | |
1246 | } | |
1247 | ||
1248 | last_visited = mem_cgroup_iter_load(iter, root, &seq); | |
1249 | } | |
1250 | ||
1251 | memcg = __mem_cgroup_iter_next(root, last_visited); | |
1252 | ||
1253 | if (reclaim) { | |
1254 | mem_cgroup_iter_update(iter, last_visited, memcg, root, | |
1255 | seq); | |
1256 | ||
1257 | if (!memcg) | |
1258 | iter->generation++; | |
1259 | else if (!prev && memcg) | |
1260 | reclaim->generation = iter->generation; | |
1261 | } | |
1262 | ||
1263 | if (prev && !memcg) | |
1264 | goto out_unlock; | |
1265 | } | |
1266 | out_unlock: | |
1267 | rcu_read_unlock(); | |
1268 | out_css_put: | |
1269 | if (prev && prev != root) | |
1270 | css_put(&prev->css); | |
1271 | ||
1272 | return memcg; | |
1273 | } | |
1274 | ||
1275 | /** | |
1276 | * mem_cgroup_iter_break - abort a hierarchy walk prematurely | |
1277 | * @root: hierarchy root | |
1278 | * @prev: last visited hierarchy member as returned by mem_cgroup_iter() | |
1279 | */ | |
1280 | void mem_cgroup_iter_break(struct mem_cgroup *root, | |
1281 | struct mem_cgroup *prev) | |
1282 | { | |
1283 | if (!root) | |
1284 | root = root_mem_cgroup; | |
1285 | if (prev && prev != root) | |
1286 | css_put(&prev->css); | |
1287 | } | |
1288 | ||
1289 | /* | |
1290 | * Iteration constructs for visiting all cgroups (under a tree). If | |
1291 | * loops are exited prematurely (break), mem_cgroup_iter_break() must | |
1292 | * be used for reference counting. | |
1293 | */ | |
1294 | #define for_each_mem_cgroup_tree(iter, root) \ | |
1295 | for (iter = mem_cgroup_iter(root, NULL, NULL); \ | |
1296 | iter != NULL; \ | |
1297 | iter = mem_cgroup_iter(root, iter, NULL)) | |
1298 | ||
1299 | #define for_each_mem_cgroup(iter) \ | |
1300 | for (iter = mem_cgroup_iter(NULL, NULL, NULL); \ | |
1301 | iter != NULL; \ | |
1302 | iter = mem_cgroup_iter(NULL, iter, NULL)) | |
1303 | ||
1304 | void __mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx) | |
1305 | { | |
1306 | struct mem_cgroup *memcg; | |
1307 | ||
1308 | rcu_read_lock(); | |
1309 | memcg = mem_cgroup_from_task(rcu_dereference(mm->owner)); | |
1310 | if (unlikely(!memcg)) | |
1311 | goto out; | |
1312 | ||
1313 | switch (idx) { | |
1314 | case PGFAULT: | |
1315 | this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGFAULT]); | |
1316 | break; | |
1317 | case PGMAJFAULT: | |
1318 | this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGMAJFAULT]); | |
1319 | break; | |
1320 | default: | |
1321 | BUG(); | |
1322 | } | |
1323 | out: | |
1324 | rcu_read_unlock(); | |
1325 | } | |
1326 | EXPORT_SYMBOL(__mem_cgroup_count_vm_event); | |
1327 | ||
1328 | /** | |
1329 | * mem_cgroup_zone_lruvec - get the lru list vector for a zone and memcg | |
1330 | * @zone: zone of the wanted lruvec | |
1331 | * @memcg: memcg of the wanted lruvec | |
1332 | * | |
1333 | * Returns the lru list vector holding pages for the given @zone and | |
1334 | * @mem. This can be the global zone lruvec, if the memory controller | |
1335 | * is disabled. | |
1336 | */ | |
1337 | struct lruvec *mem_cgroup_zone_lruvec(struct zone *zone, | |
1338 | struct mem_cgroup *memcg) | |
1339 | { | |
1340 | struct mem_cgroup_per_zone *mz; | |
1341 | struct lruvec *lruvec; | |
1342 | ||
1343 | if (mem_cgroup_disabled()) { | |
1344 | lruvec = &zone->lruvec; | |
1345 | goto out; | |
1346 | } | |
1347 | ||
1348 | mz = mem_cgroup_zoneinfo(memcg, zone_to_nid(zone), zone_idx(zone)); | |
1349 | lruvec = &mz->lruvec; | |
1350 | out: | |
1351 | /* | |
1352 | * Since a node can be onlined after the mem_cgroup was created, | |
1353 | * we have to be prepared to initialize lruvec->zone here; | |
1354 | * and if offlined then reonlined, we need to reinitialize it. | |
1355 | */ | |
1356 | if (unlikely(lruvec->zone != zone)) | |
1357 | lruvec->zone = zone; | |
1358 | return lruvec; | |
1359 | } | |
1360 | ||
1361 | /* | |
1362 | * Following LRU functions are allowed to be used without PCG_LOCK. | |
1363 | * Operations are called by routine of global LRU independently from memcg. | |
1364 | * What we have to take care of here is validness of pc->mem_cgroup. | |
1365 | * | |
1366 | * Changes to pc->mem_cgroup happens when | |
1367 | * 1. charge | |
1368 | * 2. moving account | |
1369 | * In typical case, "charge" is done before add-to-lru. Exception is SwapCache. | |
1370 | * It is added to LRU before charge. | |
1371 | * If PCG_USED bit is not set, page_cgroup is not added to this private LRU. | |
1372 | * When moving account, the page is not on LRU. It's isolated. | |
1373 | */ | |
1374 | ||
1375 | /** | |
1376 | * mem_cgroup_page_lruvec - return lruvec for adding an lru page | |
1377 | * @page: the page | |
1378 | * @zone: zone of the page | |
1379 | */ | |
1380 | struct lruvec *mem_cgroup_page_lruvec(struct page *page, struct zone *zone) | |
1381 | { | |
1382 | struct mem_cgroup_per_zone *mz; | |
1383 | struct mem_cgroup *memcg; | |
1384 | struct page_cgroup *pc; | |
1385 | struct lruvec *lruvec; | |
1386 | ||
1387 | if (mem_cgroup_disabled()) { | |
1388 | lruvec = &zone->lruvec; | |
1389 | goto out; | |
1390 | } | |
1391 | ||
1392 | pc = lookup_page_cgroup(page); | |
1393 | memcg = pc->mem_cgroup; | |
1394 | ||
1395 | /* | |
1396 | * Surreptitiously switch any uncharged offlist page to root: | |
1397 | * an uncharged page off lru does nothing to secure | |
1398 | * its former mem_cgroup from sudden removal. | |
1399 | * | |
1400 | * Our caller holds lru_lock, and PageCgroupUsed is updated | |
1401 | * under page_cgroup lock: between them, they make all uses | |
1402 | * of pc->mem_cgroup safe. | |
1403 | */ | |
1404 | if (!PageLRU(page) && !PageCgroupUsed(pc) && memcg != root_mem_cgroup) | |
1405 | pc->mem_cgroup = memcg = root_mem_cgroup; | |
1406 | ||
1407 | mz = page_cgroup_zoneinfo(memcg, page); | |
1408 | lruvec = &mz->lruvec; | |
1409 | out: | |
1410 | /* | |
1411 | * Since a node can be onlined after the mem_cgroup was created, | |
1412 | * we have to be prepared to initialize lruvec->zone here; | |
1413 | * and if offlined then reonlined, we need to reinitialize it. | |
1414 | */ | |
1415 | if (unlikely(lruvec->zone != zone)) | |
1416 | lruvec->zone = zone; | |
1417 | return lruvec; | |
1418 | } | |
1419 | ||
1420 | /** | |
1421 | * mem_cgroup_update_lru_size - account for adding or removing an lru page | |
1422 | * @lruvec: mem_cgroup per zone lru vector | |
1423 | * @lru: index of lru list the page is sitting on | |
1424 | * @nr_pages: positive when adding or negative when removing | |
1425 | * | |
1426 | * This function must be called when a page is added to or removed from an | |
1427 | * lru list. | |
1428 | */ | |
1429 | void mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru, | |
1430 | int nr_pages) | |
1431 | { | |
1432 | struct mem_cgroup_per_zone *mz; | |
1433 | unsigned long *lru_size; | |
1434 | ||
1435 | if (mem_cgroup_disabled()) | |
1436 | return; | |
1437 | ||
1438 | mz = container_of(lruvec, struct mem_cgroup_per_zone, lruvec); | |
1439 | lru_size = mz->lru_size + lru; | |
1440 | *lru_size += nr_pages; | |
1441 | VM_BUG_ON((long)(*lru_size) < 0); | |
1442 | } | |
1443 | ||
1444 | /* | |
1445 | * Checks whether given mem is same or in the root_mem_cgroup's | |
1446 | * hierarchy subtree | |
1447 | */ | |
1448 | bool __mem_cgroup_same_or_subtree(const struct mem_cgroup *root_memcg, | |
1449 | struct mem_cgroup *memcg) | |
1450 | { | |
1451 | if (root_memcg == memcg) | |
1452 | return true; | |
1453 | if (!root_memcg->use_hierarchy || !memcg) | |
1454 | return false; | |
1455 | return cgroup_is_descendant(memcg->css.cgroup, root_memcg->css.cgroup); | |
1456 | } | |
1457 | ||
1458 | static bool mem_cgroup_same_or_subtree(const struct mem_cgroup *root_memcg, | |
1459 | struct mem_cgroup *memcg) | |
1460 | { | |
1461 | bool ret; | |
1462 | ||
1463 | rcu_read_lock(); | |
1464 | ret = __mem_cgroup_same_or_subtree(root_memcg, memcg); | |
1465 | rcu_read_unlock(); | |
1466 | return ret; | |
1467 | } | |
1468 | ||
1469 | bool task_in_mem_cgroup(struct task_struct *task, | |
1470 | const struct mem_cgroup *memcg) | |
1471 | { | |
1472 | struct mem_cgroup *curr = NULL; | |
1473 | struct task_struct *p; | |
1474 | bool ret; | |
1475 | ||
1476 | p = find_lock_task_mm(task); | |
1477 | if (p) { | |
1478 | curr = get_mem_cgroup_from_mm(p->mm); | |
1479 | task_unlock(p); | |
1480 | } else { | |
1481 | /* | |
1482 | * All threads may have already detached their mm's, but the oom | |
1483 | * killer still needs to detect if they have already been oom | |
1484 | * killed to prevent needlessly killing additional tasks. | |
1485 | */ | |
1486 | rcu_read_lock(); | |
1487 | curr = mem_cgroup_from_task(task); | |
1488 | if (curr) | |
1489 | css_get(&curr->css); | |
1490 | rcu_read_unlock(); | |
1491 | } | |
1492 | /* | |
1493 | * We should check use_hierarchy of "memcg" not "curr". Because checking | |
1494 | * use_hierarchy of "curr" here make this function true if hierarchy is | |
1495 | * enabled in "curr" and "curr" is a child of "memcg" in *cgroup* | |
1496 | * hierarchy(even if use_hierarchy is disabled in "memcg"). | |
1497 | */ | |
1498 | ret = mem_cgroup_same_or_subtree(memcg, curr); | |
1499 | css_put(&curr->css); | |
1500 | return ret; | |
1501 | } | |
1502 | ||
1503 | int mem_cgroup_inactive_anon_is_low(struct lruvec *lruvec) | |
1504 | { | |
1505 | unsigned long inactive_ratio; | |
1506 | unsigned long inactive; | |
1507 | unsigned long active; | |
1508 | unsigned long gb; | |
1509 | ||
1510 | inactive = mem_cgroup_get_lru_size(lruvec, LRU_INACTIVE_ANON); | |
1511 | active = mem_cgroup_get_lru_size(lruvec, LRU_ACTIVE_ANON); | |
1512 | ||
1513 | gb = (inactive + active) >> (30 - PAGE_SHIFT); | |
1514 | if (gb) | |
1515 | inactive_ratio = int_sqrt(10 * gb); | |
1516 | else | |
1517 | inactive_ratio = 1; | |
1518 | ||
1519 | return inactive * inactive_ratio < active; | |
1520 | } | |
1521 | ||
1522 | #define mem_cgroup_from_res_counter(counter, member) \ | |
1523 | container_of(counter, struct mem_cgroup, member) | |
1524 | ||
1525 | /** | |
1526 | * mem_cgroup_margin - calculate chargeable space of a memory cgroup | |
1527 | * @memcg: the memory cgroup | |
1528 | * | |
1529 | * Returns the maximum amount of memory @mem can be charged with, in | |
1530 | * pages. | |
1531 | */ | |
1532 | static unsigned long mem_cgroup_margin(struct mem_cgroup *memcg) | |
1533 | { | |
1534 | unsigned long long margin; | |
1535 | ||
1536 | margin = res_counter_margin(&memcg->res); | |
1537 | if (do_swap_account) | |
1538 | margin = min(margin, res_counter_margin(&memcg->memsw)); | |
1539 | return margin >> PAGE_SHIFT; | |
1540 | } | |
1541 | ||
1542 | int mem_cgroup_swappiness(struct mem_cgroup *memcg) | |
1543 | { | |
1544 | /* root ? */ | |
1545 | if (!css_parent(&memcg->css)) | |
1546 | return vm_swappiness; | |
1547 | ||
1548 | return memcg->swappiness; | |
1549 | } | |
1550 | ||
1551 | /* | |
1552 | * memcg->moving_account is used for checking possibility that some thread is | |
1553 | * calling move_account(). When a thread on CPU-A starts moving pages under | |
1554 | * a memcg, other threads should check memcg->moving_account under | |
1555 | * rcu_read_lock(), like this: | |
1556 | * | |
1557 | * CPU-A CPU-B | |
1558 | * rcu_read_lock() | |
1559 | * memcg->moving_account+1 if (memcg->mocing_account) | |
1560 | * take heavy locks. | |
1561 | * synchronize_rcu() update something. | |
1562 | * rcu_read_unlock() | |
1563 | * start move here. | |
1564 | */ | |
1565 | ||
1566 | /* for quick checking without looking up memcg */ | |
1567 | atomic_t memcg_moving __read_mostly; | |
1568 | ||
1569 | static void mem_cgroup_start_move(struct mem_cgroup *memcg) | |
1570 | { | |
1571 | atomic_inc(&memcg_moving); | |
1572 | atomic_inc(&memcg->moving_account); | |
1573 | synchronize_rcu(); | |
1574 | } | |
1575 | ||
1576 | static void mem_cgroup_end_move(struct mem_cgroup *memcg) | |
1577 | { | |
1578 | /* | |
1579 | * Now, mem_cgroup_clear_mc() may call this function with NULL. | |
1580 | * We check NULL in callee rather than caller. | |
1581 | */ | |
1582 | if (memcg) { | |
1583 | atomic_dec(&memcg_moving); | |
1584 | atomic_dec(&memcg->moving_account); | |
1585 | } | |
1586 | } | |
1587 | ||
1588 | /* | |
1589 | * 2 routines for checking "mem" is under move_account() or not. | |
1590 | * | |
1591 | * mem_cgroup_stolen() - checking whether a cgroup is mc.from or not. This | |
1592 | * is used for avoiding races in accounting. If true, | |
1593 | * pc->mem_cgroup may be overwritten. | |
1594 | * | |
1595 | * mem_cgroup_under_move() - checking a cgroup is mc.from or mc.to or | |
1596 | * under hierarchy of moving cgroups. This is for | |
1597 | * waiting at hith-memory prressure caused by "move". | |
1598 | */ | |
1599 | ||
1600 | static bool mem_cgroup_stolen(struct mem_cgroup *memcg) | |
1601 | { | |
1602 | VM_BUG_ON(!rcu_read_lock_held()); | |
1603 | return atomic_read(&memcg->moving_account) > 0; | |
1604 | } | |
1605 | ||
1606 | static bool mem_cgroup_under_move(struct mem_cgroup *memcg) | |
1607 | { | |
1608 | struct mem_cgroup *from; | |
1609 | struct mem_cgroup *to; | |
1610 | bool ret = false; | |
1611 | /* | |
1612 | * Unlike task_move routines, we access mc.to, mc.from not under | |
1613 | * mutual exclusion by cgroup_mutex. Here, we take spinlock instead. | |
1614 | */ | |
1615 | spin_lock(&mc.lock); | |
1616 | from = mc.from; | |
1617 | to = mc.to; | |
1618 | if (!from) | |
1619 | goto unlock; | |
1620 | ||
1621 | ret = mem_cgroup_same_or_subtree(memcg, from) | |
1622 | || mem_cgroup_same_or_subtree(memcg, to); | |
1623 | unlock: | |
1624 | spin_unlock(&mc.lock); | |
1625 | return ret; | |
1626 | } | |
1627 | ||
1628 | static bool mem_cgroup_wait_acct_move(struct mem_cgroup *memcg) | |
1629 | { | |
1630 | if (mc.moving_task && current != mc.moving_task) { | |
1631 | if (mem_cgroup_under_move(memcg)) { | |
1632 | DEFINE_WAIT(wait); | |
1633 | prepare_to_wait(&mc.waitq, &wait, TASK_INTERRUPTIBLE); | |
1634 | /* moving charge context might have finished. */ | |
1635 | if (mc.moving_task) | |
1636 | schedule(); | |
1637 | finish_wait(&mc.waitq, &wait); | |
1638 | return true; | |
1639 | } | |
1640 | } | |
1641 | return false; | |
1642 | } | |
1643 | ||
1644 | /* | |
1645 | * Take this lock when | |
1646 | * - a code tries to modify page's memcg while it's USED. | |
1647 | * - a code tries to modify page state accounting in a memcg. | |
1648 | * see mem_cgroup_stolen(), too. | |
1649 | */ | |
1650 | static void move_lock_mem_cgroup(struct mem_cgroup *memcg, | |
1651 | unsigned long *flags) | |
1652 | { | |
1653 | spin_lock_irqsave(&memcg->move_lock, *flags); | |
1654 | } | |
1655 | ||
1656 | static void move_unlock_mem_cgroup(struct mem_cgroup *memcg, | |
1657 | unsigned long *flags) | |
1658 | { | |
1659 | spin_unlock_irqrestore(&memcg->move_lock, *flags); | |
1660 | } | |
1661 | ||
1662 | #define K(x) ((x) << (PAGE_SHIFT-10)) | |
1663 | /** | |
1664 | * mem_cgroup_print_oom_info: Print OOM information relevant to memory controller. | |
1665 | * @memcg: The memory cgroup that went over limit | |
1666 | * @p: Task that is going to be killed | |
1667 | * | |
1668 | * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is | |
1669 | * enabled | |
1670 | */ | |
1671 | void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p) | |
1672 | { | |
1673 | /* oom_info_lock ensures that parallel ooms do not interleave */ | |
1674 | static DEFINE_MUTEX(oom_info_lock); | |
1675 | struct mem_cgroup *iter; | |
1676 | unsigned int i; | |
1677 | ||
1678 | if (!p) | |
1679 | return; | |
1680 | ||
1681 | mutex_lock(&oom_info_lock); | |
1682 | rcu_read_lock(); | |
1683 | ||
1684 | pr_info("Task in "); | |
1685 | pr_cont_cgroup_path(task_cgroup(p, memory_cgrp_id)); | |
1686 | pr_info(" killed as a result of limit of "); | |
1687 | pr_cont_cgroup_path(memcg->css.cgroup); | |
1688 | pr_info("\n"); | |
1689 | ||
1690 | rcu_read_unlock(); | |
1691 | ||
1692 | pr_info("memory: usage %llukB, limit %llukB, failcnt %llu\n", | |
1693 | res_counter_read_u64(&memcg->res, RES_USAGE) >> 10, | |
1694 | res_counter_read_u64(&memcg->res, RES_LIMIT) >> 10, | |
1695 | res_counter_read_u64(&memcg->res, RES_FAILCNT)); | |
1696 | pr_info("memory+swap: usage %llukB, limit %llukB, failcnt %llu\n", | |
1697 | res_counter_read_u64(&memcg->memsw, RES_USAGE) >> 10, | |
1698 | res_counter_read_u64(&memcg->memsw, RES_LIMIT) >> 10, | |
1699 | res_counter_read_u64(&memcg->memsw, RES_FAILCNT)); | |
1700 | pr_info("kmem: usage %llukB, limit %llukB, failcnt %llu\n", | |
1701 | res_counter_read_u64(&memcg->kmem, RES_USAGE) >> 10, | |
1702 | res_counter_read_u64(&memcg->kmem, RES_LIMIT) >> 10, | |
1703 | res_counter_read_u64(&memcg->kmem, RES_FAILCNT)); | |
1704 | ||
1705 | for_each_mem_cgroup_tree(iter, memcg) { | |
1706 | pr_info("Memory cgroup stats for "); | |
1707 | pr_cont_cgroup_path(iter->css.cgroup); | |
1708 | pr_cont(":"); | |
1709 | ||
1710 | for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) { | |
1711 | if (i == MEM_CGROUP_STAT_SWAP && !do_swap_account) | |
1712 | continue; | |
1713 | pr_cont(" %s:%ldKB", mem_cgroup_stat_names[i], | |
1714 | K(mem_cgroup_read_stat(iter, i))); | |
1715 | } | |
1716 | ||
1717 | for (i = 0; i < NR_LRU_LISTS; i++) | |
1718 | pr_cont(" %s:%luKB", mem_cgroup_lru_names[i], | |
1719 | K(mem_cgroup_nr_lru_pages(iter, BIT(i)))); | |
1720 | ||
1721 | pr_cont("\n"); | |
1722 | } | |
1723 | mutex_unlock(&oom_info_lock); | |
1724 | } | |
1725 | ||
1726 | /* | |
1727 | * This function returns the number of memcg under hierarchy tree. Returns | |
1728 | * 1(self count) if no children. | |
1729 | */ | |
1730 | static int mem_cgroup_count_children(struct mem_cgroup *memcg) | |
1731 | { | |
1732 | int num = 0; | |
1733 | struct mem_cgroup *iter; | |
1734 | ||
1735 | for_each_mem_cgroup_tree(iter, memcg) | |
1736 | num++; | |
1737 | return num; | |
1738 | } | |
1739 | ||
1740 | /* | |
1741 | * Return the memory (and swap, if configured) limit for a memcg. | |
1742 | */ | |
1743 | static u64 mem_cgroup_get_limit(struct mem_cgroup *memcg) | |
1744 | { | |
1745 | u64 limit; | |
1746 | ||
1747 | limit = res_counter_read_u64(&memcg->res, RES_LIMIT); | |
1748 | ||
1749 | /* | |
1750 | * Do not consider swap space if we cannot swap due to swappiness | |
1751 | */ | |
1752 | if (mem_cgroup_swappiness(memcg)) { | |
1753 | u64 memsw; | |
1754 | ||
1755 | limit += total_swap_pages << PAGE_SHIFT; | |
1756 | memsw = res_counter_read_u64(&memcg->memsw, RES_LIMIT); | |
1757 | ||
1758 | /* | |
1759 | * If memsw is finite and limits the amount of swap space | |
1760 | * available to this memcg, return that limit. | |
1761 | */ | |
1762 | limit = min(limit, memsw); | |
1763 | } | |
1764 | ||
1765 | return limit; | |
1766 | } | |
1767 | ||
1768 | static void mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask, | |
1769 | int order) | |
1770 | { | |
1771 | struct mem_cgroup *iter; | |
1772 | unsigned long chosen_points = 0; | |
1773 | unsigned long totalpages; | |
1774 | unsigned int points = 0; | |
1775 | struct task_struct *chosen = NULL; | |
1776 | ||
1777 | /* | |
1778 | * If current has a pending SIGKILL or is exiting, then automatically | |
1779 | * select it. The goal is to allow it to allocate so that it may | |
1780 | * quickly exit and free its memory. | |
1781 | */ | |
1782 | if (fatal_signal_pending(current) || current->flags & PF_EXITING) { | |
1783 | set_thread_flag(TIF_MEMDIE); | |
1784 | return; | |
1785 | } | |
1786 | ||
1787 | check_panic_on_oom(CONSTRAINT_MEMCG, gfp_mask, order, NULL); | |
1788 | totalpages = mem_cgroup_get_limit(memcg) >> PAGE_SHIFT ? : 1; | |
1789 | for_each_mem_cgroup_tree(iter, memcg) { | |
1790 | struct css_task_iter it; | |
1791 | struct task_struct *task; | |
1792 | ||
1793 | css_task_iter_start(&iter->css, &it); | |
1794 | while ((task = css_task_iter_next(&it))) { | |
1795 | switch (oom_scan_process_thread(task, totalpages, NULL, | |
1796 | false)) { | |
1797 | case OOM_SCAN_SELECT: | |
1798 | if (chosen) | |
1799 | put_task_struct(chosen); | |
1800 | chosen = task; | |
1801 | chosen_points = ULONG_MAX; | |
1802 | get_task_struct(chosen); | |
1803 | /* fall through */ | |
1804 | case OOM_SCAN_CONTINUE: | |
1805 | continue; | |
1806 | case OOM_SCAN_ABORT: | |
1807 | css_task_iter_end(&it); | |
1808 | mem_cgroup_iter_break(memcg, iter); | |
1809 | if (chosen) | |
1810 | put_task_struct(chosen); | |
1811 | return; | |
1812 | case OOM_SCAN_OK: | |
1813 | break; | |
1814 | }; | |
1815 | points = oom_badness(task, memcg, NULL, totalpages); | |
1816 | if (!points || points < chosen_points) | |
1817 | continue; | |
1818 | /* Prefer thread group leaders for display purposes */ | |
1819 | if (points == chosen_points && | |
1820 | thread_group_leader(chosen)) | |
1821 | continue; | |
1822 | ||
1823 | if (chosen) | |
1824 | put_task_struct(chosen); | |
1825 | chosen = task; | |
1826 | chosen_points = points; | |
1827 | get_task_struct(chosen); | |
1828 | } | |
1829 | css_task_iter_end(&it); | |
1830 | } | |
1831 | ||
1832 | if (!chosen) | |
1833 | return; | |
1834 | points = chosen_points * 1000 / totalpages; | |
1835 | oom_kill_process(chosen, gfp_mask, order, points, totalpages, memcg, | |
1836 | NULL, "Memory cgroup out of memory"); | |
1837 | } | |
1838 | ||
1839 | static unsigned long mem_cgroup_reclaim(struct mem_cgroup *memcg, | |
1840 | gfp_t gfp_mask, | |
1841 | unsigned long flags) | |
1842 | { | |
1843 | unsigned long total = 0; | |
1844 | bool noswap = false; | |
1845 | int loop; | |
1846 | ||
1847 | if (flags & MEM_CGROUP_RECLAIM_NOSWAP) | |
1848 | noswap = true; | |
1849 | if (!(flags & MEM_CGROUP_RECLAIM_SHRINK) && memcg->memsw_is_minimum) | |
1850 | noswap = true; | |
1851 | ||
1852 | for (loop = 0; loop < MEM_CGROUP_MAX_RECLAIM_LOOPS; loop++) { | |
1853 | if (loop) | |
1854 | drain_all_stock_async(memcg); | |
1855 | total += try_to_free_mem_cgroup_pages(memcg, gfp_mask, noswap); | |
1856 | /* | |
1857 | * Allow limit shrinkers, which are triggered directly | |
1858 | * by userspace, to catch signals and stop reclaim | |
1859 | * after minimal progress, regardless of the margin. | |
1860 | */ | |
1861 | if (total && (flags & MEM_CGROUP_RECLAIM_SHRINK)) | |
1862 | break; | |
1863 | if (mem_cgroup_margin(memcg)) | |
1864 | break; | |
1865 | /* | |
1866 | * If nothing was reclaimed after two attempts, there | |
1867 | * may be no reclaimable pages in this hierarchy. | |
1868 | */ | |
1869 | if (loop && !total) | |
1870 | break; | |
1871 | } | |
1872 | return total; | |
1873 | } | |
1874 | ||
1875 | /** | |
1876 | * test_mem_cgroup_node_reclaimable | |
1877 | * @memcg: the target memcg | |
1878 | * @nid: the node ID to be checked. | |
1879 | * @noswap : specify true here if the user wants flle only information. | |
1880 | * | |
1881 | * This function returns whether the specified memcg contains any | |
1882 | * reclaimable pages on a node. Returns true if there are any reclaimable | |
1883 | * pages in the node. | |
1884 | */ | |
1885 | static bool test_mem_cgroup_node_reclaimable(struct mem_cgroup *memcg, | |
1886 | int nid, bool noswap) | |
1887 | { | |
1888 | if (mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL_FILE)) | |
1889 | return true; | |
1890 | if (noswap || !total_swap_pages) | |
1891 | return false; | |
1892 | if (mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL_ANON)) | |
1893 | return true; | |
1894 | return false; | |
1895 | ||
1896 | } | |
1897 | #if MAX_NUMNODES > 1 | |
1898 | ||
1899 | /* | |
1900 | * Always updating the nodemask is not very good - even if we have an empty | |
1901 | * list or the wrong list here, we can start from some node and traverse all | |
1902 | * nodes based on the zonelist. So update the list loosely once per 10 secs. | |
1903 | * | |
1904 | */ | |
1905 | static void mem_cgroup_may_update_nodemask(struct mem_cgroup *memcg) | |
1906 | { | |
1907 | int nid; | |
1908 | /* | |
1909 | * numainfo_events > 0 means there was at least NUMAINFO_EVENTS_TARGET | |
1910 | * pagein/pageout changes since the last update. | |
1911 | */ | |
1912 | if (!atomic_read(&memcg->numainfo_events)) | |
1913 | return; | |
1914 | if (atomic_inc_return(&memcg->numainfo_updating) > 1) | |
1915 | return; | |
1916 | ||
1917 | /* make a nodemask where this memcg uses memory from */ | |
1918 | memcg->scan_nodes = node_states[N_MEMORY]; | |
1919 | ||
1920 | for_each_node_mask(nid, node_states[N_MEMORY]) { | |
1921 | ||
1922 | if (!test_mem_cgroup_node_reclaimable(memcg, nid, false)) | |
1923 | node_clear(nid, memcg->scan_nodes); | |
1924 | } | |
1925 | ||
1926 | atomic_set(&memcg->numainfo_events, 0); | |
1927 | atomic_set(&memcg->numainfo_updating, 0); | |
1928 | } | |
1929 | ||
1930 | /* | |
1931 | * Selecting a node where we start reclaim from. Because what we need is just | |
1932 | * reducing usage counter, start from anywhere is O,K. Considering | |
1933 | * memory reclaim from current node, there are pros. and cons. | |
1934 | * | |
1935 | * Freeing memory from current node means freeing memory from a node which | |
1936 | * we'll use or we've used. So, it may make LRU bad. And if several threads | |
1937 | * hit limits, it will see a contention on a node. But freeing from remote | |
1938 | * node means more costs for memory reclaim because of memory latency. | |
1939 | * | |
1940 | * Now, we use round-robin. Better algorithm is welcomed. | |
1941 | */ | |
1942 | int mem_cgroup_select_victim_node(struct mem_cgroup *memcg) | |
1943 | { | |
1944 | int node; | |
1945 | ||
1946 | mem_cgroup_may_update_nodemask(memcg); | |
1947 | node = memcg->last_scanned_node; | |
1948 | ||
1949 | node = next_node(node, memcg->scan_nodes); | |
1950 | if (node == MAX_NUMNODES) | |
1951 | node = first_node(memcg->scan_nodes); | |
1952 | /* | |
1953 | * We call this when we hit limit, not when pages are added to LRU. | |
1954 | * No LRU may hold pages because all pages are UNEVICTABLE or | |
1955 | * memcg is too small and all pages are not on LRU. In that case, | |
1956 | * we use curret node. | |
1957 | */ | |
1958 | if (unlikely(node == MAX_NUMNODES)) | |
1959 | node = numa_node_id(); | |
1960 | ||
1961 | memcg->last_scanned_node = node; | |
1962 | return node; | |
1963 | } | |
1964 | ||
1965 | /* | |
1966 | * Check all nodes whether it contains reclaimable pages or not. | |
1967 | * For quick scan, we make use of scan_nodes. This will allow us to skip | |
1968 | * unused nodes. But scan_nodes is lazily updated and may not cotain | |
1969 | * enough new information. We need to do double check. | |
1970 | */ | |
1971 | static bool mem_cgroup_reclaimable(struct mem_cgroup *memcg, bool noswap) | |
1972 | { | |
1973 | int nid; | |
1974 | ||
1975 | /* | |
1976 | * quick check...making use of scan_node. | |
1977 | * We can skip unused nodes. | |
1978 | */ | |
1979 | if (!nodes_empty(memcg->scan_nodes)) { | |
1980 | for (nid = first_node(memcg->scan_nodes); | |
1981 | nid < MAX_NUMNODES; | |
1982 | nid = next_node(nid, memcg->scan_nodes)) { | |
1983 | ||
1984 | if (test_mem_cgroup_node_reclaimable(memcg, nid, noswap)) | |
1985 | return true; | |
1986 | } | |
1987 | } | |
1988 | /* | |
1989 | * Check rest of nodes. | |
1990 | */ | |
1991 | for_each_node_state(nid, N_MEMORY) { | |
1992 | if (node_isset(nid, memcg->scan_nodes)) | |
1993 | continue; | |
1994 | if (test_mem_cgroup_node_reclaimable(memcg, nid, noswap)) | |
1995 | return true; | |
1996 | } | |
1997 | return false; | |
1998 | } | |
1999 | ||
2000 | #else | |
2001 | int mem_cgroup_select_victim_node(struct mem_cgroup *memcg) | |
2002 | { | |
2003 | return 0; | |
2004 | } | |
2005 | ||
2006 | static bool mem_cgroup_reclaimable(struct mem_cgroup *memcg, bool noswap) | |
2007 | { | |
2008 | return test_mem_cgroup_node_reclaimable(memcg, 0, noswap); | |
2009 | } | |
2010 | #endif | |
2011 | ||
2012 | static int mem_cgroup_soft_reclaim(struct mem_cgroup *root_memcg, | |
2013 | struct zone *zone, | |
2014 | gfp_t gfp_mask, | |
2015 | unsigned long *total_scanned) | |
2016 | { | |
2017 | struct mem_cgroup *victim = NULL; | |
2018 | int total = 0; | |
2019 | int loop = 0; | |
2020 | unsigned long excess; | |
2021 | unsigned long nr_scanned; | |
2022 | struct mem_cgroup_reclaim_cookie reclaim = { | |
2023 | .zone = zone, | |
2024 | .priority = 0, | |
2025 | }; | |
2026 | ||
2027 | excess = res_counter_soft_limit_excess(&root_memcg->res) >> PAGE_SHIFT; | |
2028 | ||
2029 | while (1) { | |
2030 | victim = mem_cgroup_iter(root_memcg, victim, &reclaim); | |
2031 | if (!victim) { | |
2032 | loop++; | |
2033 | if (loop >= 2) { | |
2034 | /* | |
2035 | * If we have not been able to reclaim | |
2036 | * anything, it might because there are | |
2037 | * no reclaimable pages under this hierarchy | |
2038 | */ | |
2039 | if (!total) | |
2040 | break; | |
2041 | /* | |
2042 | * We want to do more targeted reclaim. | |
2043 | * excess >> 2 is not to excessive so as to | |
2044 | * reclaim too much, nor too less that we keep | |
2045 | * coming back to reclaim from this cgroup | |
2046 | */ | |
2047 | if (total >= (excess >> 2) || | |
2048 | (loop > MEM_CGROUP_MAX_RECLAIM_LOOPS)) | |
2049 | break; | |
2050 | } | |
2051 | continue; | |
2052 | } | |
2053 | if (!mem_cgroup_reclaimable(victim, false)) | |
2054 | continue; | |
2055 | total += mem_cgroup_shrink_node_zone(victim, gfp_mask, false, | |
2056 | zone, &nr_scanned); | |
2057 | *total_scanned += nr_scanned; | |
2058 | if (!res_counter_soft_limit_excess(&root_memcg->res)) | |
2059 | break; | |
2060 | } | |
2061 | mem_cgroup_iter_break(root_memcg, victim); | |
2062 | return total; | |
2063 | } | |
2064 | ||
2065 | #ifdef CONFIG_LOCKDEP | |
2066 | static struct lockdep_map memcg_oom_lock_dep_map = { | |
2067 | .name = "memcg_oom_lock", | |
2068 | }; | |
2069 | #endif | |
2070 | ||
2071 | static DEFINE_SPINLOCK(memcg_oom_lock); | |
2072 | ||
2073 | /* | |
2074 | * Check OOM-Killer is already running under our hierarchy. | |
2075 | * If someone is running, return false. | |
2076 | */ | |
2077 | static bool mem_cgroup_oom_trylock(struct mem_cgroup *memcg) | |
2078 | { | |
2079 | struct mem_cgroup *iter, *failed = NULL; | |
2080 | ||
2081 | spin_lock(&memcg_oom_lock); | |
2082 | ||
2083 | for_each_mem_cgroup_tree(iter, memcg) { | |
2084 | if (iter->oom_lock) { | |
2085 | /* | |
2086 | * this subtree of our hierarchy is already locked | |
2087 | * so we cannot give a lock. | |
2088 | */ | |
2089 | failed = iter; | |
2090 | mem_cgroup_iter_break(memcg, iter); | |
2091 | break; | |
2092 | } else | |
2093 | iter->oom_lock = true; | |
2094 | } | |
2095 | ||
2096 | if (failed) { | |
2097 | /* | |
2098 | * OK, we failed to lock the whole subtree so we have | |
2099 | * to clean up what we set up to the failing subtree | |
2100 | */ | |
2101 | for_each_mem_cgroup_tree(iter, memcg) { | |
2102 | if (iter == failed) { | |
2103 | mem_cgroup_iter_break(memcg, iter); | |
2104 | break; | |
2105 | } | |
2106 | iter->oom_lock = false; | |
2107 | } | |
2108 | } else | |
2109 | mutex_acquire(&memcg_oom_lock_dep_map, 0, 1, _RET_IP_); | |
2110 | ||
2111 | spin_unlock(&memcg_oom_lock); | |
2112 | ||
2113 | return !failed; | |
2114 | } | |
2115 | ||
2116 | static void mem_cgroup_oom_unlock(struct mem_cgroup *memcg) | |
2117 | { | |
2118 | struct mem_cgroup *iter; | |
2119 | ||
2120 | spin_lock(&memcg_oom_lock); | |
2121 | mutex_release(&memcg_oom_lock_dep_map, 1, _RET_IP_); | |
2122 | for_each_mem_cgroup_tree(iter, memcg) | |
2123 | iter->oom_lock = false; | |
2124 | spin_unlock(&memcg_oom_lock); | |
2125 | } | |
2126 | ||
2127 | static void mem_cgroup_mark_under_oom(struct mem_cgroup *memcg) | |
2128 | { | |
2129 | struct mem_cgroup *iter; | |
2130 | ||
2131 | for_each_mem_cgroup_tree(iter, memcg) | |
2132 | atomic_inc(&iter->under_oom); | |
2133 | } | |
2134 | ||
2135 | static void mem_cgroup_unmark_under_oom(struct mem_cgroup *memcg) | |
2136 | { | |
2137 | struct mem_cgroup *iter; | |
2138 | ||
2139 | /* | |
2140 | * When a new child is created while the hierarchy is under oom, | |
2141 | * mem_cgroup_oom_lock() may not be called. We have to use | |
2142 | * atomic_add_unless() here. | |
2143 | */ | |
2144 | for_each_mem_cgroup_tree(iter, memcg) | |
2145 | atomic_add_unless(&iter->under_oom, -1, 0); | |
2146 | } | |
2147 | ||
2148 | static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq); | |
2149 | ||
2150 | struct oom_wait_info { | |
2151 | struct mem_cgroup *memcg; | |
2152 | wait_queue_t wait; | |
2153 | }; | |
2154 | ||
2155 | static int memcg_oom_wake_function(wait_queue_t *wait, | |
2156 | unsigned mode, int sync, void *arg) | |
2157 | { | |
2158 | struct mem_cgroup *wake_memcg = (struct mem_cgroup *)arg; | |
2159 | struct mem_cgroup *oom_wait_memcg; | |
2160 | struct oom_wait_info *oom_wait_info; | |
2161 | ||
2162 | oom_wait_info = container_of(wait, struct oom_wait_info, wait); | |
2163 | oom_wait_memcg = oom_wait_info->memcg; | |
2164 | ||
2165 | /* | |
2166 | * Both of oom_wait_info->memcg and wake_memcg are stable under us. | |
2167 | * Then we can use css_is_ancestor without taking care of RCU. | |
2168 | */ | |
2169 | if (!mem_cgroup_same_or_subtree(oom_wait_memcg, wake_memcg) | |
2170 | && !mem_cgroup_same_or_subtree(wake_memcg, oom_wait_memcg)) | |
2171 | return 0; | |
2172 | return autoremove_wake_function(wait, mode, sync, arg); | |
2173 | } | |
2174 | ||
2175 | static void memcg_wakeup_oom(struct mem_cgroup *memcg) | |
2176 | { | |
2177 | atomic_inc(&memcg->oom_wakeups); | |
2178 | /* for filtering, pass "memcg" as argument. */ | |
2179 | __wake_up(&memcg_oom_waitq, TASK_NORMAL, 0, memcg); | |
2180 | } | |
2181 | ||
2182 | static void memcg_oom_recover(struct mem_cgroup *memcg) | |
2183 | { | |
2184 | if (memcg && atomic_read(&memcg->under_oom)) | |
2185 | memcg_wakeup_oom(memcg); | |
2186 | } | |
2187 | ||
2188 | static void mem_cgroup_oom(struct mem_cgroup *memcg, gfp_t mask, int order) | |
2189 | { | |
2190 | if (!current->memcg_oom.may_oom) | |
2191 | return; | |
2192 | /* | |
2193 | * We are in the middle of the charge context here, so we | |
2194 | * don't want to block when potentially sitting on a callstack | |
2195 | * that holds all kinds of filesystem and mm locks. | |
2196 | * | |
2197 | * Also, the caller may handle a failed allocation gracefully | |
2198 | * (like optional page cache readahead) and so an OOM killer | |
2199 | * invocation might not even be necessary. | |
2200 | * | |
2201 | * That's why we don't do anything here except remember the | |
2202 | * OOM context and then deal with it at the end of the page | |
2203 | * fault when the stack is unwound, the locks are released, | |
2204 | * and when we know whether the fault was overall successful. | |
2205 | */ | |
2206 | css_get(&memcg->css); | |
2207 | current->memcg_oom.memcg = memcg; | |
2208 | current->memcg_oom.gfp_mask = mask; | |
2209 | current->memcg_oom.order = order; | |
2210 | } | |
2211 | ||
2212 | /** | |
2213 | * mem_cgroup_oom_synchronize - complete memcg OOM handling | |
2214 | * @handle: actually kill/wait or just clean up the OOM state | |
2215 | * | |
2216 | * This has to be called at the end of a page fault if the memcg OOM | |
2217 | * handler was enabled. | |
2218 | * | |
2219 | * Memcg supports userspace OOM handling where failed allocations must | |
2220 | * sleep on a waitqueue until the userspace task resolves the | |
2221 | * situation. Sleeping directly in the charge context with all kinds | |
2222 | * of locks held is not a good idea, instead we remember an OOM state | |
2223 | * in the task and mem_cgroup_oom_synchronize() has to be called at | |
2224 | * the end of the page fault to complete the OOM handling. | |
2225 | * | |
2226 | * Returns %true if an ongoing memcg OOM situation was detected and | |
2227 | * completed, %false otherwise. | |
2228 | */ | |
2229 | bool mem_cgroup_oom_synchronize(bool handle) | |
2230 | { | |
2231 | struct mem_cgroup *memcg = current->memcg_oom.memcg; | |
2232 | struct oom_wait_info owait; | |
2233 | bool locked; | |
2234 | ||
2235 | /* OOM is global, do not handle */ | |
2236 | if (!memcg) | |
2237 | return false; | |
2238 | ||
2239 | if (!handle) | |
2240 | goto cleanup; | |
2241 | ||
2242 | owait.memcg = memcg; | |
2243 | owait.wait.flags = 0; | |
2244 | owait.wait.func = memcg_oom_wake_function; | |
2245 | owait.wait.private = current; | |
2246 | INIT_LIST_HEAD(&owait.wait.task_list); | |
2247 | ||
2248 | prepare_to_wait(&memcg_oom_waitq, &owait.wait, TASK_KILLABLE); | |
2249 | mem_cgroup_mark_under_oom(memcg); | |
2250 | ||
2251 | locked = mem_cgroup_oom_trylock(memcg); | |
2252 | ||
2253 | if (locked) | |
2254 | mem_cgroup_oom_notify(memcg); | |
2255 | ||
2256 | if (locked && !memcg->oom_kill_disable) { | |
2257 | mem_cgroup_unmark_under_oom(memcg); | |
2258 | finish_wait(&memcg_oom_waitq, &owait.wait); | |
2259 | mem_cgroup_out_of_memory(memcg, current->memcg_oom.gfp_mask, | |
2260 | current->memcg_oom.order); | |
2261 | } else { | |
2262 | schedule(); | |
2263 | mem_cgroup_unmark_under_oom(memcg); | |
2264 | finish_wait(&memcg_oom_waitq, &owait.wait); | |
2265 | } | |
2266 | ||
2267 | if (locked) { | |
2268 | mem_cgroup_oom_unlock(memcg); | |
2269 | /* | |
2270 | * There is no guarantee that an OOM-lock contender | |
2271 | * sees the wakeups triggered by the OOM kill | |
2272 | * uncharges. Wake any sleepers explicitely. | |
2273 | */ | |
2274 | memcg_oom_recover(memcg); | |
2275 | } | |
2276 | cleanup: | |
2277 | current->memcg_oom.memcg = NULL; | |
2278 | css_put(&memcg->css); | |
2279 | return true; | |
2280 | } | |
2281 | ||
2282 | /* | |
2283 | * Currently used to update mapped file statistics, but the routine can be | |
2284 | * generalized to update other statistics as well. | |
2285 | * | |
2286 | * Notes: Race condition | |
2287 | * | |
2288 | * We usually use page_cgroup_lock() for accessing page_cgroup member but | |
2289 | * it tends to be costly. But considering some conditions, we doesn't need | |
2290 | * to do so _always_. | |
2291 | * | |
2292 | * Considering "charge", lock_page_cgroup() is not required because all | |
2293 | * file-stat operations happen after a page is attached to radix-tree. There | |
2294 | * are no race with "charge". | |
2295 | * | |
2296 | * Considering "uncharge", we know that memcg doesn't clear pc->mem_cgroup | |
2297 | * at "uncharge" intentionally. So, we always see valid pc->mem_cgroup even | |
2298 | * if there are race with "uncharge". Statistics itself is properly handled | |
2299 | * by flags. | |
2300 | * | |
2301 | * Considering "move", this is an only case we see a race. To make the race | |
2302 | * small, we check mm->moving_account and detect there are possibility of race | |
2303 | * If there is, we take a lock. | |
2304 | */ | |
2305 | ||
2306 | void __mem_cgroup_begin_update_page_stat(struct page *page, | |
2307 | bool *locked, unsigned long *flags) | |
2308 | { | |
2309 | struct mem_cgroup *memcg; | |
2310 | struct page_cgroup *pc; | |
2311 | ||
2312 | pc = lookup_page_cgroup(page); | |
2313 | again: | |
2314 | memcg = pc->mem_cgroup; | |
2315 | if (unlikely(!memcg || !PageCgroupUsed(pc))) | |
2316 | return; | |
2317 | /* | |
2318 | * If this memory cgroup is not under account moving, we don't | |
2319 | * need to take move_lock_mem_cgroup(). Because we already hold | |
2320 | * rcu_read_lock(), any calls to move_account will be delayed until | |
2321 | * rcu_read_unlock() if mem_cgroup_stolen() == true. | |
2322 | */ | |
2323 | if (!mem_cgroup_stolen(memcg)) | |
2324 | return; | |
2325 | ||
2326 | move_lock_mem_cgroup(memcg, flags); | |
2327 | if (memcg != pc->mem_cgroup || !PageCgroupUsed(pc)) { | |
2328 | move_unlock_mem_cgroup(memcg, flags); | |
2329 | goto again; | |
2330 | } | |
2331 | *locked = true; | |
2332 | } | |
2333 | ||
2334 | void __mem_cgroup_end_update_page_stat(struct page *page, unsigned long *flags) | |
2335 | { | |
2336 | struct page_cgroup *pc = lookup_page_cgroup(page); | |
2337 | ||
2338 | /* | |
2339 | * It's guaranteed that pc->mem_cgroup never changes while | |
2340 | * lock is held because a routine modifies pc->mem_cgroup | |
2341 | * should take move_lock_mem_cgroup(). | |
2342 | */ | |
2343 | move_unlock_mem_cgroup(pc->mem_cgroup, flags); | |
2344 | } | |
2345 | ||
2346 | void mem_cgroup_update_page_stat(struct page *page, | |
2347 | enum mem_cgroup_stat_index idx, int val) | |
2348 | { | |
2349 | struct mem_cgroup *memcg; | |
2350 | struct page_cgroup *pc = lookup_page_cgroup(page); | |
2351 | unsigned long uninitialized_var(flags); | |
2352 | ||
2353 | if (mem_cgroup_disabled()) | |
2354 | return; | |
2355 | ||
2356 | VM_BUG_ON(!rcu_read_lock_held()); | |
2357 | memcg = pc->mem_cgroup; | |
2358 | if (unlikely(!memcg || !PageCgroupUsed(pc))) | |
2359 | return; | |
2360 | ||
2361 | this_cpu_add(memcg->stat->count[idx], val); | |
2362 | } | |
2363 | ||
2364 | /* | |
2365 | * size of first charge trial. "32" comes from vmscan.c's magic value. | |
2366 | * TODO: maybe necessary to use big numbers in big irons. | |
2367 | */ | |
2368 | #define CHARGE_BATCH 32U | |
2369 | struct memcg_stock_pcp { | |
2370 | struct mem_cgroup *cached; /* this never be root cgroup */ | |
2371 | unsigned int nr_pages; | |
2372 | struct work_struct work; | |
2373 | unsigned long flags; | |
2374 | #define FLUSHING_CACHED_CHARGE 0 | |
2375 | }; | |
2376 | static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock); | |
2377 | static DEFINE_MUTEX(percpu_charge_mutex); | |
2378 | ||
2379 | /** | |
2380 | * consume_stock: Try to consume stocked charge on this cpu. | |
2381 | * @memcg: memcg to consume from. | |
2382 | * @nr_pages: how many pages to charge. | |
2383 | * | |
2384 | * The charges will only happen if @memcg matches the current cpu's memcg | |
2385 | * stock, and at least @nr_pages are available in that stock. Failure to | |
2386 | * service an allocation will refill the stock. | |
2387 | * | |
2388 | * returns true if successful, false otherwise. | |
2389 | */ | |
2390 | static bool consume_stock(struct mem_cgroup *memcg, unsigned int nr_pages) | |
2391 | { | |
2392 | struct memcg_stock_pcp *stock; | |
2393 | bool ret = true; | |
2394 | ||
2395 | if (nr_pages > CHARGE_BATCH) | |
2396 | return false; | |
2397 | ||
2398 | stock = &get_cpu_var(memcg_stock); | |
2399 | if (memcg == stock->cached && stock->nr_pages >= nr_pages) | |
2400 | stock->nr_pages -= nr_pages; | |
2401 | else /* need to call res_counter_charge */ | |
2402 | ret = false; | |
2403 | put_cpu_var(memcg_stock); | |
2404 | return ret; | |
2405 | } | |
2406 | ||
2407 | /* | |
2408 | * Returns stocks cached in percpu to res_counter and reset cached information. | |
2409 | */ | |
2410 | static void drain_stock(struct memcg_stock_pcp *stock) | |
2411 | { | |
2412 | struct mem_cgroup *old = stock->cached; | |
2413 | ||
2414 | if (stock->nr_pages) { | |
2415 | unsigned long bytes = stock->nr_pages * PAGE_SIZE; | |
2416 | ||
2417 | res_counter_uncharge(&old->res, bytes); | |
2418 | if (do_swap_account) | |
2419 | res_counter_uncharge(&old->memsw, bytes); | |
2420 | stock->nr_pages = 0; | |
2421 | } | |
2422 | stock->cached = NULL; | |
2423 | } | |
2424 | ||
2425 | /* | |
2426 | * This must be called under preempt disabled or must be called by | |
2427 | * a thread which is pinned to local cpu. | |
2428 | */ | |
2429 | static void drain_local_stock(struct work_struct *dummy) | |
2430 | { | |
2431 | struct memcg_stock_pcp *stock = &__get_cpu_var(memcg_stock); | |
2432 | drain_stock(stock); | |
2433 | clear_bit(FLUSHING_CACHED_CHARGE, &stock->flags); | |
2434 | } | |
2435 | ||
2436 | static void __init memcg_stock_init(void) | |
2437 | { | |
2438 | int cpu; | |
2439 | ||
2440 | for_each_possible_cpu(cpu) { | |
2441 | struct memcg_stock_pcp *stock = | |
2442 | &per_cpu(memcg_stock, cpu); | |
2443 | INIT_WORK(&stock->work, drain_local_stock); | |
2444 | } | |
2445 | } | |
2446 | ||
2447 | /* | |
2448 | * Cache charges(val) which is from res_counter, to local per_cpu area. | |
2449 | * This will be consumed by consume_stock() function, later. | |
2450 | */ | |
2451 | static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages) | |
2452 | { | |
2453 | struct memcg_stock_pcp *stock = &get_cpu_var(memcg_stock); | |
2454 | ||
2455 | if (stock->cached != memcg) { /* reset if necessary */ | |
2456 | drain_stock(stock); | |
2457 | stock->cached = memcg; | |
2458 | } | |
2459 | stock->nr_pages += nr_pages; | |
2460 | put_cpu_var(memcg_stock); | |
2461 | } | |
2462 | ||
2463 | /* | |
2464 | * Drains all per-CPU charge caches for given root_memcg resp. subtree | |
2465 | * of the hierarchy under it. sync flag says whether we should block | |
2466 | * until the work is done. | |
2467 | */ | |
2468 | static void drain_all_stock(struct mem_cgroup *root_memcg, bool sync) | |
2469 | { | |
2470 | int cpu, curcpu; | |
2471 | ||
2472 | /* Notify other cpus that system-wide "drain" is running */ | |
2473 | get_online_cpus(); | |
2474 | curcpu = get_cpu(); | |
2475 | for_each_online_cpu(cpu) { | |
2476 | struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu); | |
2477 | struct mem_cgroup *memcg; | |
2478 | ||
2479 | memcg = stock->cached; | |
2480 | if (!memcg || !stock->nr_pages) | |
2481 | continue; | |
2482 | if (!mem_cgroup_same_or_subtree(root_memcg, memcg)) | |
2483 | continue; | |
2484 | if (!test_and_set_bit(FLUSHING_CACHED_CHARGE, &stock->flags)) { | |
2485 | if (cpu == curcpu) | |
2486 | drain_local_stock(&stock->work); | |
2487 | else | |
2488 | schedule_work_on(cpu, &stock->work); | |
2489 | } | |
2490 | } | |
2491 | put_cpu(); | |
2492 | ||
2493 | if (!sync) | |
2494 | goto out; | |
2495 | ||
2496 | for_each_online_cpu(cpu) { | |
2497 | struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu); | |
2498 | if (test_bit(FLUSHING_CACHED_CHARGE, &stock->flags)) | |
2499 | flush_work(&stock->work); | |
2500 | } | |
2501 | out: | |
2502 | put_online_cpus(); | |
2503 | } | |
2504 | ||
2505 | /* | |
2506 | * Tries to drain stocked charges in other cpus. This function is asynchronous | |
2507 | * and just put a work per cpu for draining localy on each cpu. Caller can | |
2508 | * expects some charges will be back to res_counter later but cannot wait for | |
2509 | * it. | |
2510 | */ | |
2511 | static void drain_all_stock_async(struct mem_cgroup *root_memcg) | |
2512 | { | |
2513 | /* | |
2514 | * If someone calls draining, avoid adding more kworker runs. | |
2515 | */ | |
2516 | if (!mutex_trylock(&percpu_charge_mutex)) | |
2517 | return; | |
2518 | drain_all_stock(root_memcg, false); | |
2519 | mutex_unlock(&percpu_charge_mutex); | |
2520 | } | |
2521 | ||
2522 | /* This is a synchronous drain interface. */ | |
2523 | static void drain_all_stock_sync(struct mem_cgroup *root_memcg) | |
2524 | { | |
2525 | /* called when force_empty is called */ | |
2526 | mutex_lock(&percpu_charge_mutex); | |
2527 | drain_all_stock(root_memcg, true); | |
2528 | mutex_unlock(&percpu_charge_mutex); | |
2529 | } | |
2530 | ||
2531 | /* | |
2532 | * This function drains percpu counter value from DEAD cpu and | |
2533 | * move it to local cpu. Note that this function can be preempted. | |
2534 | */ | |
2535 | static void mem_cgroup_drain_pcp_counter(struct mem_cgroup *memcg, int cpu) | |
2536 | { | |
2537 | int i; | |
2538 | ||
2539 | spin_lock(&memcg->pcp_counter_lock); | |
2540 | for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) { | |
2541 | long x = per_cpu(memcg->stat->count[i], cpu); | |
2542 | ||
2543 | per_cpu(memcg->stat->count[i], cpu) = 0; | |
2544 | memcg->nocpu_base.count[i] += x; | |
2545 | } | |
2546 | for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++) { | |
2547 | unsigned long x = per_cpu(memcg->stat->events[i], cpu); | |
2548 | ||
2549 | per_cpu(memcg->stat->events[i], cpu) = 0; | |
2550 | memcg->nocpu_base.events[i] += x; | |
2551 | } | |
2552 | spin_unlock(&memcg->pcp_counter_lock); | |
2553 | } | |
2554 | ||
2555 | static int memcg_cpu_hotplug_callback(struct notifier_block *nb, | |
2556 | unsigned long action, | |
2557 | void *hcpu) | |
2558 | { | |
2559 | int cpu = (unsigned long)hcpu; | |
2560 | struct memcg_stock_pcp *stock; | |
2561 | struct mem_cgroup *iter; | |
2562 | ||
2563 | if (action == CPU_ONLINE) | |
2564 | return NOTIFY_OK; | |
2565 | ||
2566 | if (action != CPU_DEAD && action != CPU_DEAD_FROZEN) | |
2567 | return NOTIFY_OK; | |
2568 | ||
2569 | for_each_mem_cgroup(iter) | |
2570 | mem_cgroup_drain_pcp_counter(iter, cpu); | |
2571 | ||
2572 | stock = &per_cpu(memcg_stock, cpu); | |
2573 | drain_stock(stock); | |
2574 | return NOTIFY_OK; | |
2575 | } | |
2576 | ||
2577 | ||
2578 | /* See __mem_cgroup_try_charge() for details */ | |
2579 | enum { | |
2580 | CHARGE_OK, /* success */ | |
2581 | CHARGE_RETRY, /* need to retry but retry is not bad */ | |
2582 | CHARGE_NOMEM, /* we can't do more. return -ENOMEM */ | |
2583 | CHARGE_WOULDBLOCK, /* GFP_WAIT wasn't set and no enough res. */ | |
2584 | }; | |
2585 | ||
2586 | static int mem_cgroup_do_charge(struct mem_cgroup *memcg, gfp_t gfp_mask, | |
2587 | unsigned int nr_pages, unsigned int min_pages, | |
2588 | bool invoke_oom) | |
2589 | { | |
2590 | unsigned long csize = nr_pages * PAGE_SIZE; | |
2591 | struct mem_cgroup *mem_over_limit; | |
2592 | struct res_counter *fail_res; | |
2593 | unsigned long flags = 0; | |
2594 | int ret; | |
2595 | ||
2596 | ret = res_counter_charge(&memcg->res, csize, &fail_res); | |
2597 | ||
2598 | if (likely(!ret)) { | |
2599 | if (!do_swap_account) | |
2600 | return CHARGE_OK; | |
2601 | ret = res_counter_charge(&memcg->memsw, csize, &fail_res); | |
2602 | if (likely(!ret)) | |
2603 | return CHARGE_OK; | |
2604 | ||
2605 | res_counter_uncharge(&memcg->res, csize); | |
2606 | mem_over_limit = mem_cgroup_from_res_counter(fail_res, memsw); | |
2607 | flags |= MEM_CGROUP_RECLAIM_NOSWAP; | |
2608 | } else | |
2609 | mem_over_limit = mem_cgroup_from_res_counter(fail_res, res); | |
2610 | /* | |
2611 | * Never reclaim on behalf of optional batching, retry with a | |
2612 | * single page instead. | |
2613 | */ | |
2614 | if (nr_pages > min_pages) | |
2615 | return CHARGE_RETRY; | |
2616 | ||
2617 | if (!(gfp_mask & __GFP_WAIT)) | |
2618 | return CHARGE_WOULDBLOCK; | |
2619 | ||
2620 | if (gfp_mask & __GFP_NORETRY) | |
2621 | return CHARGE_NOMEM; | |
2622 | ||
2623 | ret = mem_cgroup_reclaim(mem_over_limit, gfp_mask, flags); | |
2624 | if (mem_cgroup_margin(mem_over_limit) >= nr_pages) | |
2625 | return CHARGE_RETRY; | |
2626 | /* | |
2627 | * Even though the limit is exceeded at this point, reclaim | |
2628 | * may have been able to free some pages. Retry the charge | |
2629 | * before killing the task. | |
2630 | * | |
2631 | * Only for regular pages, though: huge pages are rather | |
2632 | * unlikely to succeed so close to the limit, and we fall back | |
2633 | * to regular pages anyway in case of failure. | |
2634 | */ | |
2635 | if (nr_pages <= (1 << PAGE_ALLOC_COSTLY_ORDER) && ret) | |
2636 | return CHARGE_RETRY; | |
2637 | ||
2638 | /* | |
2639 | * At task move, charge accounts can be doubly counted. So, it's | |
2640 | * better to wait until the end of task_move if something is going on. | |
2641 | */ | |
2642 | if (mem_cgroup_wait_acct_move(mem_over_limit)) | |
2643 | return CHARGE_RETRY; | |
2644 | ||
2645 | if (invoke_oom) | |
2646 | mem_cgroup_oom(mem_over_limit, gfp_mask, get_order(csize)); | |
2647 | ||
2648 | return CHARGE_NOMEM; | |
2649 | } | |
2650 | ||
2651 | /* | |
2652 | * __mem_cgroup_try_charge() does | |
2653 | * 1. detect memcg to be charged against from passed *mm and *ptr, | |
2654 | * 2. update res_counter | |
2655 | * 3. call memory reclaim if necessary. | |
2656 | * | |
2657 | * In some special case, if the task is fatal, fatal_signal_pending() or | |
2658 | * has TIF_MEMDIE, this function returns -EINTR while writing root_mem_cgroup | |
2659 | * to *ptr. There are two reasons for this. 1: fatal threads should quit as soon | |
2660 | * as possible without any hazards. 2: all pages should have a valid | |
2661 | * pc->mem_cgroup. If mm is NULL and the caller doesn't pass a valid memcg | |
2662 | * pointer, that is treated as a charge to root_mem_cgroup. | |
2663 | * | |
2664 | * So __mem_cgroup_try_charge() will return | |
2665 | * 0 ... on success, filling *ptr with a valid memcg pointer. | |
2666 | * -ENOMEM ... charge failure because of resource limits. | |
2667 | * -EINTR ... if thread is fatal. *ptr is filled with root_mem_cgroup. | |
2668 | * | |
2669 | * Unlike the exported interface, an "oom" parameter is added. if oom==true, | |
2670 | * the oom-killer can be invoked. | |
2671 | */ | |
2672 | static int __mem_cgroup_try_charge(struct mm_struct *mm, | |
2673 | gfp_t gfp_mask, | |
2674 | unsigned int nr_pages, | |
2675 | struct mem_cgroup **ptr, | |
2676 | bool oom) | |
2677 | { | |
2678 | unsigned int batch = max(CHARGE_BATCH, nr_pages); | |
2679 | int nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES; | |
2680 | struct mem_cgroup *memcg = NULL; | |
2681 | int ret; | |
2682 | ||
2683 | /* | |
2684 | * Unlike gloval-vm's OOM-kill, we're not in memory shortage | |
2685 | * in system level. So, allow to go ahead dying process in addition to | |
2686 | * MEMDIE process. | |
2687 | */ | |
2688 | if (unlikely(test_thread_flag(TIF_MEMDIE) | |
2689 | || fatal_signal_pending(current))) | |
2690 | goto bypass; | |
2691 | ||
2692 | if (unlikely(task_in_memcg_oom(current))) | |
2693 | goto nomem; | |
2694 | ||
2695 | if (gfp_mask & __GFP_NOFAIL) | |
2696 | oom = false; | |
2697 | again: | |
2698 | if (*ptr) { /* css should be a valid one */ | |
2699 | memcg = *ptr; | |
2700 | css_get(&memcg->css); | |
2701 | } else { | |
2702 | memcg = get_mem_cgroup_from_mm(mm); | |
2703 | } | |
2704 | if (mem_cgroup_is_root(memcg)) | |
2705 | goto done; | |
2706 | if (consume_stock(memcg, nr_pages)) | |
2707 | goto done; | |
2708 | ||
2709 | do { | |
2710 | bool invoke_oom = oom && !nr_oom_retries; | |
2711 | ||
2712 | /* If killed, bypass charge */ | |
2713 | if (fatal_signal_pending(current)) { | |
2714 | css_put(&memcg->css); | |
2715 | goto bypass; | |
2716 | } | |
2717 | ||
2718 | ret = mem_cgroup_do_charge(memcg, gfp_mask, batch, | |
2719 | nr_pages, invoke_oom); | |
2720 | switch (ret) { | |
2721 | case CHARGE_OK: | |
2722 | break; | |
2723 | case CHARGE_RETRY: /* not in OOM situation but retry */ | |
2724 | batch = nr_pages; | |
2725 | css_put(&memcg->css); | |
2726 | memcg = NULL; | |
2727 | goto again; | |
2728 | case CHARGE_WOULDBLOCK: /* !__GFP_WAIT */ | |
2729 | css_put(&memcg->css); | |
2730 | goto nomem; | |
2731 | case CHARGE_NOMEM: /* OOM routine works */ | |
2732 | if (!oom || invoke_oom) { | |
2733 | css_put(&memcg->css); | |
2734 | goto nomem; | |
2735 | } | |
2736 | nr_oom_retries--; | |
2737 | break; | |
2738 | } | |
2739 | } while (ret != CHARGE_OK); | |
2740 | ||
2741 | if (batch > nr_pages) | |
2742 | refill_stock(memcg, batch - nr_pages); | |
2743 | done: | |
2744 | css_put(&memcg->css); | |
2745 | *ptr = memcg; | |
2746 | return 0; | |
2747 | nomem: | |
2748 | if (!(gfp_mask & __GFP_NOFAIL)) { | |
2749 | *ptr = NULL; | |
2750 | return -ENOMEM; | |
2751 | } | |
2752 | bypass: | |
2753 | *ptr = root_mem_cgroup; | |
2754 | return -EINTR; | |
2755 | } | |
2756 | ||
2757 | /* | |
2758 | * Somemtimes we have to undo a charge we got by try_charge(). | |
2759 | * This function is for that and do uncharge, put css's refcnt. | |
2760 | * gotten by try_charge(). | |
2761 | */ | |
2762 | static void __mem_cgroup_cancel_charge(struct mem_cgroup *memcg, | |
2763 | unsigned int nr_pages) | |
2764 | { | |
2765 | if (!mem_cgroup_is_root(memcg)) { | |
2766 | unsigned long bytes = nr_pages * PAGE_SIZE; | |
2767 | ||
2768 | res_counter_uncharge(&memcg->res, bytes); | |
2769 | if (do_swap_account) | |
2770 | res_counter_uncharge(&memcg->memsw, bytes); | |
2771 | } | |
2772 | } | |
2773 | ||
2774 | /* | |
2775 | * Cancel chrages in this cgroup....doesn't propagate to parent cgroup. | |
2776 | * This is useful when moving usage to parent cgroup. | |
2777 | */ | |
2778 | static void __mem_cgroup_cancel_local_charge(struct mem_cgroup *memcg, | |
2779 | unsigned int nr_pages) | |
2780 | { | |
2781 | unsigned long bytes = nr_pages * PAGE_SIZE; | |
2782 | ||
2783 | if (mem_cgroup_is_root(memcg)) | |
2784 | return; | |
2785 | ||
2786 | res_counter_uncharge_until(&memcg->res, memcg->res.parent, bytes); | |
2787 | if (do_swap_account) | |
2788 | res_counter_uncharge_until(&memcg->memsw, | |
2789 | memcg->memsw.parent, bytes); | |
2790 | } | |
2791 | ||
2792 | /* | |
2793 | * A helper function to get mem_cgroup from ID. must be called under | |
2794 | * rcu_read_lock(). The caller is responsible for calling css_tryget if | |
2795 | * the mem_cgroup is used for charging. (dropping refcnt from swap can be | |
2796 | * called against removed memcg.) | |
2797 | */ | |
2798 | static struct mem_cgroup *mem_cgroup_lookup(unsigned short id) | |
2799 | { | |
2800 | /* ID 0 is unused ID */ | |
2801 | if (!id) | |
2802 | return NULL; | |
2803 | return mem_cgroup_from_id(id); | |
2804 | } | |
2805 | ||
2806 | struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page) | |
2807 | { | |
2808 | struct mem_cgroup *memcg = NULL; | |
2809 | struct page_cgroup *pc; | |
2810 | unsigned short id; | |
2811 | swp_entry_t ent; | |
2812 | ||
2813 | VM_BUG_ON_PAGE(!PageLocked(page), page); | |
2814 | ||
2815 | pc = lookup_page_cgroup(page); | |
2816 | lock_page_cgroup(pc); | |
2817 | if (PageCgroupUsed(pc)) { | |
2818 | memcg = pc->mem_cgroup; | |
2819 | if (memcg && !css_tryget(&memcg->css)) | |
2820 | memcg = NULL; | |
2821 | } else if (PageSwapCache(page)) { | |
2822 | ent.val = page_private(page); | |
2823 | id = lookup_swap_cgroup_id(ent); | |
2824 | rcu_read_lock(); | |
2825 | memcg = mem_cgroup_lookup(id); | |
2826 | if (memcg && !css_tryget(&memcg->css)) | |
2827 | memcg = NULL; | |
2828 | rcu_read_unlock(); | |
2829 | } | |
2830 | unlock_page_cgroup(pc); | |
2831 | return memcg; | |
2832 | } | |
2833 | ||
2834 | static void __mem_cgroup_commit_charge(struct mem_cgroup *memcg, | |
2835 | struct page *page, | |
2836 | unsigned int nr_pages, | |
2837 | enum charge_type ctype, | |
2838 | bool lrucare) | |
2839 | { | |
2840 | struct page_cgroup *pc = lookup_page_cgroup(page); | |
2841 | struct zone *uninitialized_var(zone); | |
2842 | struct lruvec *lruvec; | |
2843 | bool was_on_lru = false; | |
2844 | bool anon; | |
2845 | ||
2846 | lock_page_cgroup(pc); | |
2847 | VM_BUG_ON_PAGE(PageCgroupUsed(pc), page); | |
2848 | /* | |
2849 | * we don't need page_cgroup_lock about tail pages, becase they are not | |
2850 | * accessed by any other context at this point. | |
2851 | */ | |
2852 | ||
2853 | /* | |
2854 | * In some cases, SwapCache and FUSE(splice_buf->radixtree), the page | |
2855 | * may already be on some other mem_cgroup's LRU. Take care of it. | |
2856 | */ | |
2857 | if (lrucare) { | |
2858 | zone = page_zone(page); | |
2859 | spin_lock_irq(&zone->lru_lock); | |
2860 | if (PageLRU(page)) { | |
2861 | lruvec = mem_cgroup_zone_lruvec(zone, pc->mem_cgroup); | |
2862 | ClearPageLRU(page); | |
2863 | del_page_from_lru_list(page, lruvec, page_lru(page)); | |
2864 | was_on_lru = true; | |
2865 | } | |
2866 | } | |
2867 | ||
2868 | pc->mem_cgroup = memcg; | |
2869 | /* | |
2870 | * We access a page_cgroup asynchronously without lock_page_cgroup(). | |
2871 | * Especially when a page_cgroup is taken from a page, pc->mem_cgroup | |
2872 | * is accessed after testing USED bit. To make pc->mem_cgroup visible | |
2873 | * before USED bit, we need memory barrier here. | |
2874 | * See mem_cgroup_add_lru_list(), etc. | |
2875 | */ | |
2876 | smp_wmb(); | |
2877 | SetPageCgroupUsed(pc); | |
2878 | ||
2879 | if (lrucare) { | |
2880 | if (was_on_lru) { | |
2881 | lruvec = mem_cgroup_zone_lruvec(zone, pc->mem_cgroup); | |
2882 | VM_BUG_ON_PAGE(PageLRU(page), page); | |
2883 | SetPageLRU(page); | |
2884 | add_page_to_lru_list(page, lruvec, page_lru(page)); | |
2885 | } | |
2886 | spin_unlock_irq(&zone->lru_lock); | |
2887 | } | |
2888 | ||
2889 | if (ctype == MEM_CGROUP_CHARGE_TYPE_ANON) | |
2890 | anon = true; | |
2891 | else | |
2892 | anon = false; | |
2893 | ||
2894 | mem_cgroup_charge_statistics(memcg, page, anon, nr_pages); | |
2895 | unlock_page_cgroup(pc); | |
2896 | ||
2897 | /* | |
2898 | * "charge_statistics" updated event counter. Then, check it. | |
2899 | * Insert ancestor (and ancestor's ancestors), to softlimit RB-tree. | |
2900 | * if they exceeds softlimit. | |
2901 | */ | |
2902 | memcg_check_events(memcg, page); | |
2903 | } | |
2904 | ||
2905 | static DEFINE_MUTEX(set_limit_mutex); | |
2906 | ||
2907 | #ifdef CONFIG_MEMCG_KMEM | |
2908 | static DEFINE_MUTEX(activate_kmem_mutex); | |
2909 | ||
2910 | static inline bool memcg_can_account_kmem(struct mem_cgroup *memcg) | |
2911 | { | |
2912 | return !mem_cgroup_disabled() && !mem_cgroup_is_root(memcg) && | |
2913 | memcg_kmem_is_active(memcg); | |
2914 | } | |
2915 | ||
2916 | /* | |
2917 | * This is a bit cumbersome, but it is rarely used and avoids a backpointer | |
2918 | * in the memcg_cache_params struct. | |
2919 | */ | |
2920 | static struct kmem_cache *memcg_params_to_cache(struct memcg_cache_params *p) | |
2921 | { | |
2922 | struct kmem_cache *cachep; | |
2923 | ||
2924 | VM_BUG_ON(p->is_root_cache); | |
2925 | cachep = p->root_cache; | |
2926 | return cache_from_memcg_idx(cachep, memcg_cache_id(p->memcg)); | |
2927 | } | |
2928 | ||
2929 | #ifdef CONFIG_SLABINFO | |
2930 | static int mem_cgroup_slabinfo_read(struct seq_file *m, void *v) | |
2931 | { | |
2932 | struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m)); | |
2933 | struct memcg_cache_params *params; | |
2934 | ||
2935 | if (!memcg_can_account_kmem(memcg)) | |
2936 | return -EIO; | |
2937 | ||
2938 | print_slabinfo_header(m); | |
2939 | ||
2940 | mutex_lock(&memcg->slab_caches_mutex); | |
2941 | list_for_each_entry(params, &memcg->memcg_slab_caches, list) | |
2942 | cache_show(memcg_params_to_cache(params), m); | |
2943 | mutex_unlock(&memcg->slab_caches_mutex); | |
2944 | ||
2945 | return 0; | |
2946 | } | |
2947 | #endif | |
2948 | ||
2949 | static int memcg_charge_kmem(struct mem_cgroup *memcg, gfp_t gfp, u64 size) | |
2950 | { | |
2951 | struct res_counter *fail_res; | |
2952 | struct mem_cgroup *_memcg; | |
2953 | int ret = 0; | |
2954 | ||
2955 | ret = res_counter_charge(&memcg->kmem, size, &fail_res); | |
2956 | if (ret) | |
2957 | return ret; | |
2958 | ||
2959 | _memcg = memcg; | |
2960 | ret = __mem_cgroup_try_charge(NULL, gfp, size >> PAGE_SHIFT, | |
2961 | &_memcg, oom_gfp_allowed(gfp)); | |
2962 | ||
2963 | if (ret == -EINTR) { | |
2964 | /* | |
2965 | * __mem_cgroup_try_charge() chosed to bypass to root due to | |
2966 | * OOM kill or fatal signal. Since our only options are to | |
2967 | * either fail the allocation or charge it to this cgroup, do | |
2968 | * it as a temporary condition. But we can't fail. From a | |
2969 | * kmem/slab perspective, the cache has already been selected, | |
2970 | * by mem_cgroup_kmem_get_cache(), so it is too late to change | |
2971 | * our minds. | |
2972 | * | |
2973 | * This condition will only trigger if the task entered | |
2974 | * memcg_charge_kmem in a sane state, but was OOM-killed during | |
2975 | * __mem_cgroup_try_charge() above. Tasks that were already | |
2976 | * dying when the allocation triggers should have been already | |
2977 | * directed to the root cgroup in memcontrol.h | |
2978 | */ | |
2979 | res_counter_charge_nofail(&memcg->res, size, &fail_res); | |
2980 | if (do_swap_account) | |
2981 | res_counter_charge_nofail(&memcg->memsw, size, | |
2982 | &fail_res); | |
2983 | ret = 0; | |
2984 | } else if (ret) | |
2985 | res_counter_uncharge(&memcg->kmem, size); | |
2986 | ||
2987 | return ret; | |
2988 | } | |
2989 | ||
2990 | static void memcg_uncharge_kmem(struct mem_cgroup *memcg, u64 size) | |
2991 | { | |
2992 | res_counter_uncharge(&memcg->res, size); | |
2993 | if (do_swap_account) | |
2994 | res_counter_uncharge(&memcg->memsw, size); | |
2995 | ||
2996 | /* Not down to 0 */ | |
2997 | if (res_counter_uncharge(&memcg->kmem, size)) | |
2998 | return; | |
2999 | ||
3000 | /* | |
3001 | * Releases a reference taken in kmem_cgroup_css_offline in case | |
3002 | * this last uncharge is racing with the offlining code or it is | |
3003 | * outliving the memcg existence. | |
3004 | * | |
3005 | * The memory barrier imposed by test&clear is paired with the | |
3006 | * explicit one in memcg_kmem_mark_dead(). | |
3007 | */ | |
3008 | if (memcg_kmem_test_and_clear_dead(memcg)) | |
3009 | css_put(&memcg->css); | |
3010 | } | |
3011 | ||
3012 | /* | |
3013 | * helper for acessing a memcg's index. It will be used as an index in the | |
3014 | * child cache array in kmem_cache, and also to derive its name. This function | |
3015 | * will return -1 when this is not a kmem-limited memcg. | |
3016 | */ | |
3017 | int memcg_cache_id(struct mem_cgroup *memcg) | |
3018 | { | |
3019 | return memcg ? memcg->kmemcg_id : -1; | |
3020 | } | |
3021 | ||
3022 | static size_t memcg_caches_array_size(int num_groups) | |
3023 | { | |
3024 | ssize_t size; | |
3025 | if (num_groups <= 0) | |
3026 | return 0; | |
3027 | ||
3028 | size = 2 * num_groups; | |
3029 | if (size < MEMCG_CACHES_MIN_SIZE) | |
3030 | size = MEMCG_CACHES_MIN_SIZE; | |
3031 | else if (size > MEMCG_CACHES_MAX_SIZE) | |
3032 | size = MEMCG_CACHES_MAX_SIZE; | |
3033 | ||
3034 | return size; | |
3035 | } | |
3036 | ||
3037 | /* | |
3038 | * We should update the current array size iff all caches updates succeed. This | |
3039 | * can only be done from the slab side. The slab mutex needs to be held when | |
3040 | * calling this. | |
3041 | */ | |
3042 | void memcg_update_array_size(int num) | |
3043 | { | |
3044 | if (num > memcg_limited_groups_array_size) | |
3045 | memcg_limited_groups_array_size = memcg_caches_array_size(num); | |
3046 | } | |
3047 | ||
3048 | static void kmem_cache_destroy_work_func(struct work_struct *w); | |
3049 | ||
3050 | int memcg_update_cache_size(struct kmem_cache *s, int num_groups) | |
3051 | { | |
3052 | struct memcg_cache_params *cur_params = s->memcg_params; | |
3053 | ||
3054 | VM_BUG_ON(!is_root_cache(s)); | |
3055 | ||
3056 | if (num_groups > memcg_limited_groups_array_size) { | |
3057 | int i; | |
3058 | struct memcg_cache_params *new_params; | |
3059 | ssize_t size = memcg_caches_array_size(num_groups); | |
3060 | ||
3061 | size *= sizeof(void *); | |
3062 | size += offsetof(struct memcg_cache_params, memcg_caches); | |
3063 | ||
3064 | new_params = kzalloc(size, GFP_KERNEL); | |
3065 | if (!new_params) | |
3066 | return -ENOMEM; | |
3067 | ||
3068 | new_params->is_root_cache = true; | |
3069 | ||
3070 | /* | |
3071 | * There is the chance it will be bigger than | |
3072 | * memcg_limited_groups_array_size, if we failed an allocation | |
3073 | * in a cache, in which case all caches updated before it, will | |
3074 | * have a bigger array. | |
3075 | * | |
3076 | * But if that is the case, the data after | |
3077 | * memcg_limited_groups_array_size is certainly unused | |
3078 | */ | |
3079 | for (i = 0; i < memcg_limited_groups_array_size; i++) { | |
3080 | if (!cur_params->memcg_caches[i]) | |
3081 | continue; | |
3082 | new_params->memcg_caches[i] = | |
3083 | cur_params->memcg_caches[i]; | |
3084 | } | |
3085 | ||
3086 | /* | |
3087 | * Ideally, we would wait until all caches succeed, and only | |
3088 | * then free the old one. But this is not worth the extra | |
3089 | * pointer per-cache we'd have to have for this. | |
3090 | * | |
3091 | * It is not a big deal if some caches are left with a size | |
3092 | * bigger than the others. And all updates will reset this | |
3093 | * anyway. | |
3094 | */ | |
3095 | rcu_assign_pointer(s->memcg_params, new_params); | |
3096 | if (cur_params) | |
3097 | kfree_rcu(cur_params, rcu_head); | |
3098 | } | |
3099 | return 0; | |
3100 | } | |
3101 | ||
3102 | int memcg_alloc_cache_params(struct mem_cgroup *memcg, struct kmem_cache *s, | |
3103 | struct kmem_cache *root_cache) | |
3104 | { | |
3105 | size_t size; | |
3106 | ||
3107 | if (!memcg_kmem_enabled()) | |
3108 | return 0; | |
3109 | ||
3110 | if (!memcg) { | |
3111 | size = offsetof(struct memcg_cache_params, memcg_caches); | |
3112 | size += memcg_limited_groups_array_size * sizeof(void *); | |
3113 | } else | |
3114 | size = sizeof(struct memcg_cache_params); | |
3115 | ||
3116 | s->memcg_params = kzalloc(size, GFP_KERNEL); | |
3117 | if (!s->memcg_params) | |
3118 | return -ENOMEM; | |
3119 | ||
3120 | if (memcg) { | |
3121 | s->memcg_params->memcg = memcg; | |
3122 | s->memcg_params->root_cache = root_cache; | |
3123 | INIT_WORK(&s->memcg_params->destroy, | |
3124 | kmem_cache_destroy_work_func); | |
3125 | } else | |
3126 | s->memcg_params->is_root_cache = true; | |
3127 | ||
3128 | return 0; | |
3129 | } | |
3130 | ||
3131 | void memcg_free_cache_params(struct kmem_cache *s) | |
3132 | { | |
3133 | kfree(s->memcg_params); | |
3134 | } | |
3135 | ||
3136 | void memcg_register_cache(struct kmem_cache *s) | |
3137 | { | |
3138 | struct kmem_cache *root; | |
3139 | struct mem_cgroup *memcg; | |
3140 | int id; | |
3141 | ||
3142 | if (is_root_cache(s)) | |
3143 | return; | |
3144 | ||
3145 | /* | |
3146 | * Holding the slab_mutex assures nobody will touch the memcg_caches | |
3147 | * array while we are modifying it. | |
3148 | */ | |
3149 | lockdep_assert_held(&slab_mutex); | |
3150 | ||
3151 | root = s->memcg_params->root_cache; | |
3152 | memcg = s->memcg_params->memcg; | |
3153 | id = memcg_cache_id(memcg); | |
3154 | ||
3155 | css_get(&memcg->css); | |
3156 | ||
3157 | ||
3158 | /* | |
3159 | * Since readers won't lock (see cache_from_memcg_idx()), we need a | |
3160 | * barrier here to ensure nobody will see the kmem_cache partially | |
3161 | * initialized. | |
3162 | */ | |
3163 | smp_wmb(); | |
3164 | ||
3165 | /* | |
3166 | * Initialize the pointer to this cache in its parent's memcg_params | |
3167 | * before adding it to the memcg_slab_caches list, otherwise we can | |
3168 | * fail to convert memcg_params_to_cache() while traversing the list. | |
3169 | */ | |
3170 | VM_BUG_ON(root->memcg_params->memcg_caches[id]); | |
3171 | root->memcg_params->memcg_caches[id] = s; | |
3172 | ||
3173 | mutex_lock(&memcg->slab_caches_mutex); | |
3174 | list_add(&s->memcg_params->list, &memcg->memcg_slab_caches); | |
3175 | mutex_unlock(&memcg->slab_caches_mutex); | |
3176 | } | |
3177 | ||
3178 | void memcg_unregister_cache(struct kmem_cache *s) | |
3179 | { | |
3180 | struct kmem_cache *root; | |
3181 | struct mem_cgroup *memcg; | |
3182 | int id; | |
3183 | ||
3184 | if (is_root_cache(s)) | |
3185 | return; | |
3186 | ||
3187 | /* | |
3188 | * Holding the slab_mutex assures nobody will touch the memcg_caches | |
3189 | * array while we are modifying it. | |
3190 | */ | |
3191 | lockdep_assert_held(&slab_mutex); | |
3192 | ||
3193 | root = s->memcg_params->root_cache; | |
3194 | memcg = s->memcg_params->memcg; | |
3195 | id = memcg_cache_id(memcg); | |
3196 | ||
3197 | mutex_lock(&memcg->slab_caches_mutex); | |
3198 | list_del(&s->memcg_params->list); | |
3199 | mutex_unlock(&memcg->slab_caches_mutex); | |
3200 | ||
3201 | /* | |
3202 | * Clear the pointer to this cache in its parent's memcg_params only | |
3203 | * after removing it from the memcg_slab_caches list, otherwise we can | |
3204 | * fail to convert memcg_params_to_cache() while traversing the list. | |
3205 | */ | |
3206 | VM_BUG_ON(!root->memcg_params->memcg_caches[id]); | |
3207 | root->memcg_params->memcg_caches[id] = NULL; | |
3208 | ||
3209 | css_put(&memcg->css); | |
3210 | } | |
3211 | ||
3212 | /* | |
3213 | * During the creation a new cache, we need to disable our accounting mechanism | |
3214 | * altogether. This is true even if we are not creating, but rather just | |
3215 | * enqueing new caches to be created. | |
3216 | * | |
3217 | * This is because that process will trigger allocations; some visible, like | |
3218 | * explicit kmallocs to auxiliary data structures, name strings and internal | |
3219 | * cache structures; some well concealed, like INIT_WORK() that can allocate | |
3220 | * objects during debug. | |
3221 | * | |
3222 | * If any allocation happens during memcg_kmem_get_cache, we will recurse back | |
3223 | * to it. This may not be a bounded recursion: since the first cache creation | |
3224 | * failed to complete (waiting on the allocation), we'll just try to create the | |
3225 | * cache again, failing at the same point. | |
3226 | * | |
3227 | * memcg_kmem_get_cache is prepared to abort after seeing a positive count of | |
3228 | * memcg_kmem_skip_account. So we enclose anything that might allocate memory | |
3229 | * inside the following two functions. | |
3230 | */ | |
3231 | static inline void memcg_stop_kmem_account(void) | |
3232 | { | |
3233 | VM_BUG_ON(!current->mm); | |
3234 | current->memcg_kmem_skip_account++; | |
3235 | } | |
3236 | ||
3237 | static inline void memcg_resume_kmem_account(void) | |
3238 | { | |
3239 | VM_BUG_ON(!current->mm); | |
3240 | current->memcg_kmem_skip_account--; | |
3241 | } | |
3242 | ||
3243 | static void kmem_cache_destroy_work_func(struct work_struct *w) | |
3244 | { | |
3245 | struct kmem_cache *cachep; | |
3246 | struct memcg_cache_params *p; | |
3247 | ||
3248 | p = container_of(w, struct memcg_cache_params, destroy); | |
3249 | ||
3250 | cachep = memcg_params_to_cache(p); | |
3251 | ||
3252 | /* | |
3253 | * If we get down to 0 after shrink, we could delete right away. | |
3254 | * However, memcg_release_pages() already puts us back in the workqueue | |
3255 | * in that case. If we proceed deleting, we'll get a dangling | |
3256 | * reference, and removing the object from the workqueue in that case | |
3257 | * is unnecessary complication. We are not a fast path. | |
3258 | * | |
3259 | * Note that this case is fundamentally different from racing with | |
3260 | * shrink_slab(): if memcg_cgroup_destroy_cache() is called in | |
3261 | * kmem_cache_shrink, not only we would be reinserting a dead cache | |
3262 | * into the queue, but doing so from inside the worker racing to | |
3263 | * destroy it. | |
3264 | * | |
3265 | * So if we aren't down to zero, we'll just schedule a worker and try | |
3266 | * again | |
3267 | */ | |
3268 | if (atomic_read(&cachep->memcg_params->nr_pages) != 0) | |
3269 | kmem_cache_shrink(cachep); | |
3270 | else | |
3271 | kmem_cache_destroy(cachep); | |
3272 | } | |
3273 | ||
3274 | void mem_cgroup_destroy_cache(struct kmem_cache *cachep) | |
3275 | { | |
3276 | if (!cachep->memcg_params->dead) | |
3277 | return; | |
3278 | ||
3279 | /* | |
3280 | * There are many ways in which we can get here. | |
3281 | * | |
3282 | * We can get to a memory-pressure situation while the delayed work is | |
3283 | * still pending to run. The vmscan shrinkers can then release all | |
3284 | * cache memory and get us to destruction. If this is the case, we'll | |
3285 | * be executed twice, which is a bug (the second time will execute over | |
3286 | * bogus data). In this case, cancelling the work should be fine. | |
3287 | * | |
3288 | * But we can also get here from the worker itself, if | |
3289 | * kmem_cache_shrink is enough to shake all the remaining objects and | |
3290 | * get the page count to 0. In this case, we'll deadlock if we try to | |
3291 | * cancel the work (the worker runs with an internal lock held, which | |
3292 | * is the same lock we would hold for cancel_work_sync().) | |
3293 | * | |
3294 | * Since we can't possibly know who got us here, just refrain from | |
3295 | * running if there is already work pending | |
3296 | */ | |
3297 | if (work_pending(&cachep->memcg_params->destroy)) | |
3298 | return; | |
3299 | /* | |
3300 | * We have to defer the actual destroying to a workqueue, because | |
3301 | * we might currently be in a context that cannot sleep. | |
3302 | */ | |
3303 | schedule_work(&cachep->memcg_params->destroy); | |
3304 | } | |
3305 | ||
3306 | static struct kmem_cache *memcg_create_kmem_cache(struct mem_cgroup *memcg, | |
3307 | struct kmem_cache *s) | |
3308 | { | |
3309 | struct kmem_cache *new = NULL; | |
3310 | static char *tmp_path = NULL, *tmp_name = NULL; | |
3311 | static DEFINE_MUTEX(mutex); /* protects tmp_name */ | |
3312 | ||
3313 | BUG_ON(!memcg_can_account_kmem(memcg)); | |
3314 | ||
3315 | mutex_lock(&mutex); | |
3316 | /* | |
3317 | * kmem_cache_create_memcg duplicates the given name and | |
3318 | * cgroup_name for this name requires RCU context. | |
3319 | * This static temporary buffer is used to prevent from | |
3320 | * pointless shortliving allocation. | |
3321 | */ | |
3322 | if (!tmp_path || !tmp_name) { | |
3323 | if (!tmp_path) | |
3324 | tmp_path = kmalloc(PATH_MAX, GFP_KERNEL); | |
3325 | if (!tmp_name) | |
3326 | tmp_name = kmalloc(NAME_MAX + 1, GFP_KERNEL); | |
3327 | if (!tmp_path || !tmp_name) | |
3328 | goto out; | |
3329 | } | |
3330 | ||
3331 | cgroup_name(memcg->css.cgroup, tmp_name, NAME_MAX + 1); | |
3332 | snprintf(tmp_path, PATH_MAX, "%s(%d:%s)", s->name, | |
3333 | memcg_cache_id(memcg), tmp_name); | |
3334 | ||
3335 | new = kmem_cache_create_memcg(memcg, tmp_path, s->object_size, s->align, | |
3336 | (s->flags & ~SLAB_PANIC), s->ctor, s); | |
3337 | if (new) | |
3338 | new->allocflags |= __GFP_KMEMCG; | |
3339 | else | |
3340 | new = s; | |
3341 | out: | |
3342 | mutex_unlock(&mutex); | |
3343 | return new; | |
3344 | } | |
3345 | ||
3346 | void kmem_cache_destroy_memcg_children(struct kmem_cache *s) | |
3347 | { | |
3348 | struct kmem_cache *c; | |
3349 | int i; | |
3350 | ||
3351 | if (!s->memcg_params) | |
3352 | return; | |
3353 | if (!s->memcg_params->is_root_cache) | |
3354 | return; | |
3355 | ||
3356 | /* | |
3357 | * If the cache is being destroyed, we trust that there is no one else | |
3358 | * requesting objects from it. Even if there are, the sanity checks in | |
3359 | * kmem_cache_destroy should caught this ill-case. | |
3360 | * | |
3361 | * Still, we don't want anyone else freeing memcg_caches under our | |
3362 | * noses, which can happen if a new memcg comes to life. As usual, | |
3363 | * we'll take the activate_kmem_mutex to protect ourselves against | |
3364 | * this. | |
3365 | */ | |
3366 | mutex_lock(&activate_kmem_mutex); | |
3367 | for_each_memcg_cache_index(i) { | |
3368 | c = cache_from_memcg_idx(s, i); | |
3369 | if (!c) | |
3370 | continue; | |
3371 | ||
3372 | /* | |
3373 | * We will now manually delete the caches, so to avoid races | |
3374 | * we need to cancel all pending destruction workers and | |
3375 | * proceed with destruction ourselves. | |
3376 | * | |
3377 | * kmem_cache_destroy() will call kmem_cache_shrink internally, | |
3378 | * and that could spawn the workers again: it is likely that | |
3379 | * the cache still have active pages until this very moment. | |
3380 | * This would lead us back to mem_cgroup_destroy_cache. | |
3381 | * | |
3382 | * But that will not execute at all if the "dead" flag is not | |
3383 | * set, so flip it down to guarantee we are in control. | |
3384 | */ | |
3385 | c->memcg_params->dead = false; | |
3386 | cancel_work_sync(&c->memcg_params->destroy); | |
3387 | kmem_cache_destroy(c); | |
3388 | } | |
3389 | mutex_unlock(&activate_kmem_mutex); | |
3390 | } | |
3391 | ||
3392 | struct create_work { | |
3393 | struct mem_cgroup *memcg; | |
3394 | struct kmem_cache *cachep; | |
3395 | struct work_struct work; | |
3396 | }; | |
3397 | ||
3398 | static void mem_cgroup_destroy_all_caches(struct mem_cgroup *memcg) | |
3399 | { | |
3400 | struct kmem_cache *cachep; | |
3401 | struct memcg_cache_params *params; | |
3402 | ||
3403 | if (!memcg_kmem_is_active(memcg)) | |
3404 | return; | |
3405 | ||
3406 | mutex_lock(&memcg->slab_caches_mutex); | |
3407 | list_for_each_entry(params, &memcg->memcg_slab_caches, list) { | |
3408 | cachep = memcg_params_to_cache(params); | |
3409 | cachep->memcg_params->dead = true; | |
3410 | schedule_work(&cachep->memcg_params->destroy); | |
3411 | } | |
3412 | mutex_unlock(&memcg->slab_caches_mutex); | |
3413 | } | |
3414 | ||
3415 | static void memcg_create_cache_work_func(struct work_struct *w) | |
3416 | { | |
3417 | struct create_work *cw; | |
3418 | ||
3419 | cw = container_of(w, struct create_work, work); | |
3420 | memcg_create_kmem_cache(cw->memcg, cw->cachep); | |
3421 | css_put(&cw->memcg->css); | |
3422 | kfree(cw); | |
3423 | } | |
3424 | ||
3425 | /* | |
3426 | * Enqueue the creation of a per-memcg kmem_cache. | |
3427 | */ | |
3428 | static void __memcg_create_cache_enqueue(struct mem_cgroup *memcg, | |
3429 | struct kmem_cache *cachep) | |
3430 | { | |
3431 | struct create_work *cw; | |
3432 | ||
3433 | cw = kmalloc(sizeof(struct create_work), GFP_NOWAIT); | |
3434 | if (cw == NULL) { | |
3435 | css_put(&memcg->css); | |
3436 | return; | |
3437 | } | |
3438 | ||
3439 | cw->memcg = memcg; | |
3440 | cw->cachep = cachep; | |
3441 | ||
3442 | INIT_WORK(&cw->work, memcg_create_cache_work_func); | |
3443 | schedule_work(&cw->work); | |
3444 | } | |
3445 | ||
3446 | static void memcg_create_cache_enqueue(struct mem_cgroup *memcg, | |
3447 | struct kmem_cache *cachep) | |
3448 | { | |
3449 | /* | |
3450 | * We need to stop accounting when we kmalloc, because if the | |
3451 | * corresponding kmalloc cache is not yet created, the first allocation | |
3452 | * in __memcg_create_cache_enqueue will recurse. | |
3453 | * | |
3454 | * However, it is better to enclose the whole function. Depending on | |
3455 | * the debugging options enabled, INIT_WORK(), for instance, can | |
3456 | * trigger an allocation. This too, will make us recurse. Because at | |
3457 | * this point we can't allow ourselves back into memcg_kmem_get_cache, | |
3458 | * the safest choice is to do it like this, wrapping the whole function. | |
3459 | */ | |
3460 | memcg_stop_kmem_account(); | |
3461 | __memcg_create_cache_enqueue(memcg, cachep); | |
3462 | memcg_resume_kmem_account(); | |
3463 | } | |
3464 | /* | |
3465 | * Return the kmem_cache we're supposed to use for a slab allocation. | |
3466 | * We try to use the current memcg's version of the cache. | |
3467 | * | |
3468 | * If the cache does not exist yet, if we are the first user of it, | |
3469 | * we either create it immediately, if possible, or create it asynchronously | |
3470 | * in a workqueue. | |
3471 | * In the latter case, we will let the current allocation go through with | |
3472 | * the original cache. | |
3473 | * | |
3474 | * Can't be called in interrupt context or from kernel threads. | |
3475 | * This function needs to be called with rcu_read_lock() held. | |
3476 | */ | |
3477 | struct kmem_cache *__memcg_kmem_get_cache(struct kmem_cache *cachep, | |
3478 | gfp_t gfp) | |
3479 | { | |
3480 | struct mem_cgroup *memcg; | |
3481 | struct kmem_cache *memcg_cachep; | |
3482 | ||
3483 | VM_BUG_ON(!cachep->memcg_params); | |
3484 | VM_BUG_ON(!cachep->memcg_params->is_root_cache); | |
3485 | ||
3486 | if (!current->mm || current->memcg_kmem_skip_account) | |
3487 | return cachep; | |
3488 | ||
3489 | rcu_read_lock(); | |
3490 | memcg = mem_cgroup_from_task(rcu_dereference(current->mm->owner)); | |
3491 | ||
3492 | if (!memcg_can_account_kmem(memcg)) | |
3493 | goto out; | |
3494 | ||
3495 | memcg_cachep = cache_from_memcg_idx(cachep, memcg_cache_id(memcg)); | |
3496 | if (likely(memcg_cachep)) { | |
3497 | cachep = memcg_cachep; | |
3498 | goto out; | |
3499 | } | |
3500 | ||
3501 | /* The corresponding put will be done in the workqueue. */ | |
3502 | if (!css_tryget(&memcg->css)) | |
3503 | goto out; | |
3504 | rcu_read_unlock(); | |
3505 | ||
3506 | /* | |
3507 | * If we are in a safe context (can wait, and not in interrupt | |
3508 | * context), we could be be predictable and return right away. | |
3509 | * This would guarantee that the allocation being performed | |
3510 | * already belongs in the new cache. | |
3511 | * | |
3512 | * However, there are some clashes that can arrive from locking. | |
3513 | * For instance, because we acquire the slab_mutex while doing | |
3514 | * kmem_cache_dup, this means no further allocation could happen | |
3515 | * with the slab_mutex held. | |
3516 | * | |
3517 | * Also, because cache creation issue get_online_cpus(), this | |
3518 | * creates a lock chain: memcg_slab_mutex -> cpu_hotplug_mutex, | |
3519 | * that ends up reversed during cpu hotplug. (cpuset allocates | |
3520 | * a bunch of GFP_KERNEL memory during cpuup). Due to all that, | |
3521 | * better to defer everything. | |
3522 | */ | |
3523 | memcg_create_cache_enqueue(memcg, cachep); | |
3524 | return cachep; | |
3525 | out: | |
3526 | rcu_read_unlock(); | |
3527 | return cachep; | |
3528 | } | |
3529 | EXPORT_SYMBOL(__memcg_kmem_get_cache); | |
3530 | ||
3531 | /* | |
3532 | * We need to verify if the allocation against current->mm->owner's memcg is | |
3533 | * possible for the given order. But the page is not allocated yet, so we'll | |
3534 | * need a further commit step to do the final arrangements. | |
3535 | * | |
3536 | * It is possible for the task to switch cgroups in this mean time, so at | |
3537 | * commit time, we can't rely on task conversion any longer. We'll then use | |
3538 | * the handle argument to return to the caller which cgroup we should commit | |
3539 | * against. We could also return the memcg directly and avoid the pointer | |
3540 | * passing, but a boolean return value gives better semantics considering | |
3541 | * the compiled-out case as well. | |
3542 | * | |
3543 | * Returning true means the allocation is possible. | |
3544 | */ | |
3545 | bool | |
3546 | __memcg_kmem_newpage_charge(gfp_t gfp, struct mem_cgroup **_memcg, int order) | |
3547 | { | |
3548 | struct mem_cgroup *memcg; | |
3549 | int ret; | |
3550 | ||
3551 | *_memcg = NULL; | |
3552 | ||
3553 | /* | |
3554 | * Disabling accounting is only relevant for some specific memcg | |
3555 | * internal allocations. Therefore we would initially not have such | |
3556 | * check here, since direct calls to the page allocator that are marked | |
3557 | * with GFP_KMEMCG only happen outside memcg core. We are mostly | |
3558 | * concerned with cache allocations, and by having this test at | |
3559 | * memcg_kmem_get_cache, we are already able to relay the allocation to | |
3560 | * the root cache and bypass the memcg cache altogether. | |
3561 | * | |
3562 | * There is one exception, though: the SLUB allocator does not create | |
3563 | * large order caches, but rather service large kmallocs directly from | |
3564 | * the page allocator. Therefore, the following sequence when backed by | |
3565 | * the SLUB allocator: | |
3566 | * | |
3567 | * memcg_stop_kmem_account(); | |
3568 | * kmalloc(<large_number>) | |
3569 | * memcg_resume_kmem_account(); | |
3570 | * | |
3571 | * would effectively ignore the fact that we should skip accounting, | |
3572 | * since it will drive us directly to this function without passing | |
3573 | * through the cache selector memcg_kmem_get_cache. Such large | |
3574 | * allocations are extremely rare but can happen, for instance, for the | |
3575 | * cache arrays. We bring this test here. | |
3576 | */ | |
3577 | if (!current->mm || current->memcg_kmem_skip_account) | |
3578 | return true; | |
3579 | ||
3580 | memcg = get_mem_cgroup_from_mm(current->mm); | |
3581 | ||
3582 | if (!memcg_can_account_kmem(memcg)) { | |
3583 | css_put(&memcg->css); | |
3584 | return true; | |
3585 | } | |
3586 | ||
3587 | ret = memcg_charge_kmem(memcg, gfp, PAGE_SIZE << order); | |
3588 | if (!ret) | |
3589 | *_memcg = memcg; | |
3590 | ||
3591 | css_put(&memcg->css); | |
3592 | return (ret == 0); | |
3593 | } | |
3594 | ||
3595 | void __memcg_kmem_commit_charge(struct page *page, struct mem_cgroup *memcg, | |
3596 | int order) | |
3597 | { | |
3598 | struct page_cgroup *pc; | |
3599 | ||
3600 | VM_BUG_ON(mem_cgroup_is_root(memcg)); | |
3601 | ||
3602 | /* The page allocation failed. Revert */ | |
3603 | if (!page) { | |
3604 | memcg_uncharge_kmem(memcg, PAGE_SIZE << order); | |
3605 | return; | |
3606 | } | |
3607 | ||
3608 | pc = lookup_page_cgroup(page); | |
3609 | lock_page_cgroup(pc); | |
3610 | pc->mem_cgroup = memcg; | |
3611 | SetPageCgroupUsed(pc); | |
3612 | unlock_page_cgroup(pc); | |
3613 | } | |
3614 | ||
3615 | void __memcg_kmem_uncharge_pages(struct page *page, int order) | |
3616 | { | |
3617 | struct mem_cgroup *memcg = NULL; | |
3618 | struct page_cgroup *pc; | |
3619 | ||
3620 | ||
3621 | pc = lookup_page_cgroup(page); | |
3622 | /* | |
3623 | * Fast unlocked return. Theoretically might have changed, have to | |
3624 | * check again after locking. | |
3625 | */ | |
3626 | if (!PageCgroupUsed(pc)) | |
3627 | return; | |
3628 | ||
3629 | lock_page_cgroup(pc); | |
3630 | if (PageCgroupUsed(pc)) { | |
3631 | memcg = pc->mem_cgroup; | |
3632 | ClearPageCgroupUsed(pc); | |
3633 | } | |
3634 | unlock_page_cgroup(pc); | |
3635 | ||
3636 | /* | |
3637 | * We trust that only if there is a memcg associated with the page, it | |
3638 | * is a valid allocation | |
3639 | */ | |
3640 | if (!memcg) | |
3641 | return; | |
3642 | ||
3643 | VM_BUG_ON_PAGE(mem_cgroup_is_root(memcg), page); | |
3644 | memcg_uncharge_kmem(memcg, PAGE_SIZE << order); | |
3645 | } | |
3646 | #else | |
3647 | static inline void mem_cgroup_destroy_all_caches(struct mem_cgroup *memcg) | |
3648 | { | |
3649 | } | |
3650 | #endif /* CONFIG_MEMCG_KMEM */ | |
3651 | ||
3652 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE | |
3653 | ||
3654 | #define PCGF_NOCOPY_AT_SPLIT (1 << PCG_LOCK | 1 << PCG_MIGRATION) | |
3655 | /* | |
3656 | * Because tail pages are not marked as "used", set it. We're under | |
3657 | * zone->lru_lock, 'splitting on pmd' and compound_lock. | |
3658 | * charge/uncharge will be never happen and move_account() is done under | |
3659 | * compound_lock(), so we don't have to take care of races. | |
3660 | */ | |
3661 | void mem_cgroup_split_huge_fixup(struct page *head) | |
3662 | { | |
3663 | struct page_cgroup *head_pc = lookup_page_cgroup(head); | |
3664 | struct page_cgroup *pc; | |
3665 | struct mem_cgroup *memcg; | |
3666 | int i; | |
3667 | ||
3668 | if (mem_cgroup_disabled()) | |
3669 | return; | |
3670 | ||
3671 | memcg = head_pc->mem_cgroup; | |
3672 | for (i = 1; i < HPAGE_PMD_NR; i++) { | |
3673 | pc = head_pc + i; | |
3674 | pc->mem_cgroup = memcg; | |
3675 | smp_wmb();/* see __commit_charge() */ | |
3676 | pc->flags = head_pc->flags & ~PCGF_NOCOPY_AT_SPLIT; | |
3677 | } | |
3678 | __this_cpu_sub(memcg->stat->count[MEM_CGROUP_STAT_RSS_HUGE], | |
3679 | HPAGE_PMD_NR); | |
3680 | } | |
3681 | #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ | |
3682 | ||
3683 | /** | |
3684 | * mem_cgroup_move_account - move account of the page | |
3685 | * @page: the page | |
3686 | * @nr_pages: number of regular pages (>1 for huge pages) | |
3687 | * @pc: page_cgroup of the page. | |
3688 | * @from: mem_cgroup which the page is moved from. | |
3689 | * @to: mem_cgroup which the page is moved to. @from != @to. | |
3690 | * | |
3691 | * The caller must confirm following. | |
3692 | * - page is not on LRU (isolate_page() is useful.) | |
3693 | * - compound_lock is held when nr_pages > 1 | |
3694 | * | |
3695 | * This function doesn't do "charge" to new cgroup and doesn't do "uncharge" | |
3696 | * from old cgroup. | |
3697 | */ | |
3698 | static int mem_cgroup_move_account(struct page *page, | |
3699 | unsigned int nr_pages, | |
3700 | struct page_cgroup *pc, | |
3701 | struct mem_cgroup *from, | |
3702 | struct mem_cgroup *to) | |
3703 | { | |
3704 | unsigned long flags; | |
3705 | int ret; | |
3706 | bool anon = PageAnon(page); | |
3707 | ||
3708 | VM_BUG_ON(from == to); | |
3709 | VM_BUG_ON_PAGE(PageLRU(page), page); | |
3710 | /* | |
3711 | * The page is isolated from LRU. So, collapse function | |
3712 | * will not handle this page. But page splitting can happen. | |
3713 | * Do this check under compound_page_lock(). The caller should | |
3714 | * hold it. | |
3715 | */ | |
3716 | ret = -EBUSY; | |
3717 | if (nr_pages > 1 && !PageTransHuge(page)) | |
3718 | goto out; | |
3719 | ||
3720 | lock_page_cgroup(pc); | |
3721 | ||
3722 | ret = -EINVAL; | |
3723 | if (!PageCgroupUsed(pc) || pc->mem_cgroup != from) | |
3724 | goto unlock; | |
3725 | ||
3726 | move_lock_mem_cgroup(from, &flags); | |
3727 | ||
3728 | if (!anon && page_mapped(page)) { | |
3729 | __this_cpu_sub(from->stat->count[MEM_CGROUP_STAT_FILE_MAPPED], | |
3730 | nr_pages); | |
3731 | __this_cpu_add(to->stat->count[MEM_CGROUP_STAT_FILE_MAPPED], | |
3732 | nr_pages); | |
3733 | } | |
3734 | ||
3735 | if (PageWriteback(page)) { | |
3736 | __this_cpu_sub(from->stat->count[MEM_CGROUP_STAT_WRITEBACK], | |
3737 | nr_pages); | |
3738 | __this_cpu_add(to->stat->count[MEM_CGROUP_STAT_WRITEBACK], | |
3739 | nr_pages); | |
3740 | } | |
3741 | ||
3742 | mem_cgroup_charge_statistics(from, page, anon, -nr_pages); | |
3743 | ||
3744 | /* caller should have done css_get */ | |
3745 | pc->mem_cgroup = to; | |
3746 | mem_cgroup_charge_statistics(to, page, anon, nr_pages); | |
3747 | move_unlock_mem_cgroup(from, &flags); | |
3748 | ret = 0; | |
3749 | unlock: | |
3750 | unlock_page_cgroup(pc); | |
3751 | /* | |
3752 | * check events | |
3753 | */ | |
3754 | memcg_check_events(to, page); | |
3755 | memcg_check_events(from, page); | |
3756 | out: | |
3757 | return ret; | |
3758 | } | |
3759 | ||
3760 | /** | |
3761 | * mem_cgroup_move_parent - moves page to the parent group | |
3762 | * @page: the page to move | |
3763 | * @pc: page_cgroup of the page | |
3764 | * @child: page's cgroup | |
3765 | * | |
3766 | * move charges to its parent or the root cgroup if the group has no | |
3767 | * parent (aka use_hierarchy==0). | |
3768 | * Although this might fail (get_page_unless_zero, isolate_lru_page or | |
3769 | * mem_cgroup_move_account fails) the failure is always temporary and | |
3770 | * it signals a race with a page removal/uncharge or migration. In the | |
3771 | * first case the page is on the way out and it will vanish from the LRU | |
3772 | * on the next attempt and the call should be retried later. | |
3773 | * Isolation from the LRU fails only if page has been isolated from | |
3774 | * the LRU since we looked at it and that usually means either global | |
3775 | * reclaim or migration going on. The page will either get back to the | |
3776 | * LRU or vanish. | |
3777 | * Finaly mem_cgroup_move_account fails only if the page got uncharged | |
3778 | * (!PageCgroupUsed) or moved to a different group. The page will | |
3779 | * disappear in the next attempt. | |
3780 | */ | |
3781 | static int mem_cgroup_move_parent(struct page *page, | |
3782 | struct page_cgroup *pc, | |
3783 | struct mem_cgroup *child) | |
3784 | { | |
3785 | struct mem_cgroup *parent; | |
3786 | unsigned int nr_pages; | |
3787 | unsigned long uninitialized_var(flags); | |
3788 | int ret; | |
3789 | ||
3790 | VM_BUG_ON(mem_cgroup_is_root(child)); | |
3791 | ||
3792 | ret = -EBUSY; | |
3793 | if (!get_page_unless_zero(page)) | |
3794 | goto out; | |
3795 | if (isolate_lru_page(page)) | |
3796 | goto put; | |
3797 | ||
3798 | nr_pages = hpage_nr_pages(page); | |
3799 | ||
3800 | parent = parent_mem_cgroup(child); | |
3801 | /* | |
3802 | * If no parent, move charges to root cgroup. | |
3803 | */ | |
3804 | if (!parent) | |
3805 | parent = root_mem_cgroup; | |
3806 | ||
3807 | if (nr_pages > 1) { | |
3808 | VM_BUG_ON_PAGE(!PageTransHuge(page), page); | |
3809 | flags = compound_lock_irqsave(page); | |
3810 | } | |
3811 | ||
3812 | ret = mem_cgroup_move_account(page, nr_pages, | |
3813 | pc, child, parent); | |
3814 | if (!ret) | |
3815 | __mem_cgroup_cancel_local_charge(child, nr_pages); | |
3816 | ||
3817 | if (nr_pages > 1) | |
3818 | compound_unlock_irqrestore(page, flags); | |
3819 | putback_lru_page(page); | |
3820 | put: | |
3821 | put_page(page); | |
3822 | out: | |
3823 | return ret; | |
3824 | } | |
3825 | ||
3826 | int mem_cgroup_newpage_charge(struct page *page, | |
3827 | struct mm_struct *mm, gfp_t gfp_mask) | |
3828 | { | |
3829 | struct mem_cgroup *memcg = NULL; | |
3830 | unsigned int nr_pages = 1; | |
3831 | bool oom = true; | |
3832 | int ret; | |
3833 | ||
3834 | if (mem_cgroup_disabled()) | |
3835 | return 0; | |
3836 | ||
3837 | VM_BUG_ON_PAGE(page_mapped(page), page); | |
3838 | VM_BUG_ON_PAGE(page->mapping && !PageAnon(page), page); | |
3839 | VM_BUG_ON(!mm); | |
3840 | ||
3841 | if (PageTransHuge(page)) { | |
3842 | nr_pages <<= compound_order(page); | |
3843 | VM_BUG_ON_PAGE(!PageTransHuge(page), page); | |
3844 | /* | |
3845 | * Never OOM-kill a process for a huge page. The | |
3846 | * fault handler will fall back to regular pages. | |
3847 | */ | |
3848 | oom = false; | |
3849 | } | |
3850 | ||
3851 | ret = __mem_cgroup_try_charge(mm, gfp_mask, nr_pages, &memcg, oom); | |
3852 | if (ret == -ENOMEM) | |
3853 | return ret; | |
3854 | __mem_cgroup_commit_charge(memcg, page, nr_pages, | |
3855 | MEM_CGROUP_CHARGE_TYPE_ANON, false); | |
3856 | return 0; | |
3857 | } | |
3858 | ||
3859 | /* | |
3860 | * While swap-in, try_charge -> commit or cancel, the page is locked. | |
3861 | * And when try_charge() successfully returns, one refcnt to memcg without | |
3862 | * struct page_cgroup is acquired. This refcnt will be consumed by | |
3863 | * "commit()" or removed by "cancel()" | |
3864 | */ | |
3865 | static int __mem_cgroup_try_charge_swapin(struct mm_struct *mm, | |
3866 | struct page *page, | |
3867 | gfp_t mask, | |
3868 | struct mem_cgroup **memcgp) | |
3869 | { | |
3870 | struct mem_cgroup *memcg; | |
3871 | struct page_cgroup *pc; | |
3872 | int ret; | |
3873 | ||
3874 | pc = lookup_page_cgroup(page); | |
3875 | /* | |
3876 | * Every swap fault against a single page tries to charge the | |
3877 | * page, bail as early as possible. shmem_unuse() encounters | |
3878 | * already charged pages, too. The USED bit is protected by | |
3879 | * the page lock, which serializes swap cache removal, which | |
3880 | * in turn serializes uncharging. | |
3881 | */ | |
3882 | if (PageCgroupUsed(pc)) | |
3883 | return 0; | |
3884 | if (!do_swap_account) | |
3885 | goto charge_cur_mm; | |
3886 | memcg = try_get_mem_cgroup_from_page(page); | |
3887 | if (!memcg) | |
3888 | goto charge_cur_mm; | |
3889 | *memcgp = memcg; | |
3890 | ret = __mem_cgroup_try_charge(NULL, mask, 1, memcgp, true); | |
3891 | css_put(&memcg->css); | |
3892 | if (ret == -EINTR) | |
3893 | ret = 0; | |
3894 | return ret; | |
3895 | charge_cur_mm: | |
3896 | ret = __mem_cgroup_try_charge(mm, mask, 1, memcgp, true); | |
3897 | if (ret == -EINTR) | |
3898 | ret = 0; | |
3899 | return ret; | |
3900 | } | |
3901 | ||
3902 | int mem_cgroup_try_charge_swapin(struct mm_struct *mm, struct page *page, | |
3903 | gfp_t gfp_mask, struct mem_cgroup **memcgp) | |
3904 | { | |
3905 | *memcgp = NULL; | |
3906 | if (mem_cgroup_disabled()) | |
3907 | return 0; | |
3908 | /* | |
3909 | * A racing thread's fault, or swapoff, may have already | |
3910 | * updated the pte, and even removed page from swap cache: in | |
3911 | * those cases unuse_pte()'s pte_same() test will fail; but | |
3912 | * there's also a KSM case which does need to charge the page. | |
3913 | */ | |
3914 | if (!PageSwapCache(page)) { | |
3915 | int ret; | |
3916 | ||
3917 | ret = __mem_cgroup_try_charge(mm, gfp_mask, 1, memcgp, true); | |
3918 | if (ret == -EINTR) | |
3919 | ret = 0; | |
3920 | return ret; | |
3921 | } | |
3922 | return __mem_cgroup_try_charge_swapin(mm, page, gfp_mask, memcgp); | |
3923 | } | |
3924 | ||
3925 | void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *memcg) | |
3926 | { | |
3927 | if (mem_cgroup_disabled()) | |
3928 | return; | |
3929 | if (!memcg) | |
3930 | return; | |
3931 | __mem_cgroup_cancel_charge(memcg, 1); | |
3932 | } | |
3933 | ||
3934 | static void | |
3935 | __mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *memcg, | |
3936 | enum charge_type ctype) | |
3937 | { | |
3938 | if (mem_cgroup_disabled()) | |
3939 | return; | |
3940 | if (!memcg) | |
3941 | return; | |
3942 | ||
3943 | __mem_cgroup_commit_charge(memcg, page, 1, ctype, true); | |
3944 | /* | |
3945 | * Now swap is on-memory. This means this page may be | |
3946 | * counted both as mem and swap....double count. | |
3947 | * Fix it by uncharging from memsw. Basically, this SwapCache is stable | |
3948 | * under lock_page(). But in do_swap_page()::memory.c, reuse_swap_page() | |
3949 | * may call delete_from_swap_cache() before reach here. | |
3950 | */ | |
3951 | if (do_swap_account && PageSwapCache(page)) { | |
3952 | swp_entry_t ent = {.val = page_private(page)}; | |
3953 | mem_cgroup_uncharge_swap(ent); | |
3954 | } | |
3955 | } | |
3956 | ||
3957 | void mem_cgroup_commit_charge_swapin(struct page *page, | |
3958 | struct mem_cgroup *memcg) | |
3959 | { | |
3960 | __mem_cgroup_commit_charge_swapin(page, memcg, | |
3961 | MEM_CGROUP_CHARGE_TYPE_ANON); | |
3962 | } | |
3963 | ||
3964 | int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm, | |
3965 | gfp_t gfp_mask) | |
3966 | { | |
3967 | struct mem_cgroup *memcg = NULL; | |
3968 | enum charge_type type = MEM_CGROUP_CHARGE_TYPE_CACHE; | |
3969 | int ret; | |
3970 | ||
3971 | if (mem_cgroup_disabled()) | |
3972 | return 0; | |
3973 | if (PageCompound(page)) | |
3974 | return 0; | |
3975 | ||
3976 | if (!PageSwapCache(page)) { | |
3977 | /* | |
3978 | * Page cache insertions can happen without an actual | |
3979 | * task context, e.g. during disk probing on boot. | |
3980 | */ | |
3981 | if (!mm) | |
3982 | memcg = root_mem_cgroup; | |
3983 | ret = __mem_cgroup_try_charge(mm, gfp_mask, 1, &memcg, true); | |
3984 | if (ret != -ENOMEM) | |
3985 | __mem_cgroup_commit_charge(memcg, page, 1, type, false); | |
3986 | } else { /* page is swapcache/shmem */ | |
3987 | ret = __mem_cgroup_try_charge_swapin(mm, page, | |
3988 | gfp_mask, &memcg); | |
3989 | if (!ret) | |
3990 | __mem_cgroup_commit_charge_swapin(page, memcg, type); | |
3991 | } | |
3992 | return ret; | |
3993 | } | |
3994 | ||
3995 | static void mem_cgroup_do_uncharge(struct mem_cgroup *memcg, | |
3996 | unsigned int nr_pages, | |
3997 | const enum charge_type ctype) | |
3998 | { | |
3999 | struct memcg_batch_info *batch = NULL; | |
4000 | bool uncharge_memsw = true; | |
4001 | ||
4002 | /* If swapout, usage of swap doesn't decrease */ | |
4003 | if (!do_swap_account || ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT) | |
4004 | uncharge_memsw = false; | |
4005 | ||
4006 | batch = ¤t->memcg_batch; | |
4007 | /* | |
4008 | * In usual, we do css_get() when we remember memcg pointer. | |
4009 | * But in this case, we keep res->usage until end of a series of | |
4010 | * uncharges. Then, it's ok to ignore memcg's refcnt. | |
4011 | */ | |
4012 | if (!batch->memcg) | |
4013 | batch->memcg = memcg; | |
4014 | /* | |
4015 | * do_batch > 0 when unmapping pages or inode invalidate/truncate. | |
4016 | * In those cases, all pages freed continuously can be expected to be in | |
4017 | * the same cgroup and we have chance to coalesce uncharges. | |
4018 | * But we do uncharge one by one if this is killed by OOM(TIF_MEMDIE) | |
4019 | * because we want to do uncharge as soon as possible. | |
4020 | */ | |
4021 | ||
4022 | if (!batch->do_batch || test_thread_flag(TIF_MEMDIE)) | |
4023 | goto direct_uncharge; | |
4024 | ||
4025 | if (nr_pages > 1) | |
4026 | goto direct_uncharge; | |
4027 | ||
4028 | /* | |
4029 | * In typical case, batch->memcg == mem. This means we can | |
4030 | * merge a series of uncharges to an uncharge of res_counter. | |
4031 | * If not, we uncharge res_counter ony by one. | |
4032 | */ | |
4033 | if (batch->memcg != memcg) | |
4034 | goto direct_uncharge; | |
4035 | /* remember freed charge and uncharge it later */ | |
4036 | batch->nr_pages++; | |
4037 | if (uncharge_memsw) | |
4038 | batch->memsw_nr_pages++; | |
4039 | return; | |
4040 | direct_uncharge: | |
4041 | res_counter_uncharge(&memcg->res, nr_pages * PAGE_SIZE); | |
4042 | if (uncharge_memsw) | |
4043 | res_counter_uncharge(&memcg->memsw, nr_pages * PAGE_SIZE); | |
4044 | if (unlikely(batch->memcg != memcg)) | |
4045 | memcg_oom_recover(memcg); | |
4046 | } | |
4047 | ||
4048 | /* | |
4049 | * uncharge if !page_mapped(page) | |
4050 | */ | |
4051 | static struct mem_cgroup * | |
4052 | __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype, | |
4053 | bool end_migration) | |
4054 | { | |
4055 | struct mem_cgroup *memcg = NULL; | |
4056 | unsigned int nr_pages = 1; | |
4057 | struct page_cgroup *pc; | |
4058 | bool anon; | |
4059 | ||
4060 | if (mem_cgroup_disabled()) | |
4061 | return NULL; | |
4062 | ||
4063 | if (PageTransHuge(page)) { | |
4064 | nr_pages <<= compound_order(page); | |
4065 | VM_BUG_ON_PAGE(!PageTransHuge(page), page); | |
4066 | } | |
4067 | /* | |
4068 | * Check if our page_cgroup is valid | |
4069 | */ | |
4070 | pc = lookup_page_cgroup(page); | |
4071 | if (unlikely(!PageCgroupUsed(pc))) | |
4072 | return NULL; | |
4073 | ||
4074 | lock_page_cgroup(pc); | |
4075 | ||
4076 | memcg = pc->mem_cgroup; | |
4077 | ||
4078 | if (!PageCgroupUsed(pc)) | |
4079 | goto unlock_out; | |
4080 | ||
4081 | anon = PageAnon(page); | |
4082 | ||
4083 | switch (ctype) { | |
4084 | case MEM_CGROUP_CHARGE_TYPE_ANON: | |
4085 | /* | |
4086 | * Generally PageAnon tells if it's the anon statistics to be | |
4087 | * updated; but sometimes e.g. mem_cgroup_uncharge_page() is | |
4088 | * used before page reached the stage of being marked PageAnon. | |
4089 | */ | |
4090 | anon = true; | |
4091 | /* fallthrough */ | |
4092 | case MEM_CGROUP_CHARGE_TYPE_DROP: | |
4093 | /* See mem_cgroup_prepare_migration() */ | |
4094 | if (page_mapped(page)) | |
4095 | goto unlock_out; | |
4096 | /* | |
4097 | * Pages under migration may not be uncharged. But | |
4098 | * end_migration() /must/ be the one uncharging the | |
4099 | * unused post-migration page and so it has to call | |
4100 | * here with the migration bit still set. See the | |
4101 | * res_counter handling below. | |
4102 | */ | |
4103 | if (!end_migration && PageCgroupMigration(pc)) | |
4104 | goto unlock_out; | |
4105 | break; | |
4106 | case MEM_CGROUP_CHARGE_TYPE_SWAPOUT: | |
4107 | if (!PageAnon(page)) { /* Shared memory */ | |
4108 | if (page->mapping && !page_is_file_cache(page)) | |
4109 | goto unlock_out; | |
4110 | } else if (page_mapped(page)) /* Anon */ | |
4111 | goto unlock_out; | |
4112 | break; | |
4113 | default: | |
4114 | break; | |
4115 | } | |
4116 | ||
4117 | mem_cgroup_charge_statistics(memcg, page, anon, -nr_pages); | |
4118 | ||
4119 | ClearPageCgroupUsed(pc); | |
4120 | /* | |
4121 | * pc->mem_cgroup is not cleared here. It will be accessed when it's | |
4122 | * freed from LRU. This is safe because uncharged page is expected not | |
4123 | * to be reused (freed soon). Exception is SwapCache, it's handled by | |
4124 | * special functions. | |
4125 | */ | |
4126 | ||
4127 | unlock_page_cgroup(pc); | |
4128 | /* | |
4129 | * even after unlock, we have memcg->res.usage here and this memcg | |
4130 | * will never be freed, so it's safe to call css_get(). | |
4131 | */ | |
4132 | memcg_check_events(memcg, page); | |
4133 | if (do_swap_account && ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT) { | |
4134 | mem_cgroup_swap_statistics(memcg, true); | |
4135 | css_get(&memcg->css); | |
4136 | } | |
4137 | /* | |
4138 | * Migration does not charge the res_counter for the | |
4139 | * replacement page, so leave it alone when phasing out the | |
4140 | * page that is unused after the migration. | |
4141 | */ | |
4142 | if (!end_migration && !mem_cgroup_is_root(memcg)) | |
4143 | mem_cgroup_do_uncharge(memcg, nr_pages, ctype); | |
4144 | ||
4145 | return memcg; | |
4146 | ||
4147 | unlock_out: | |
4148 | unlock_page_cgroup(pc); | |
4149 | return NULL; | |
4150 | } | |
4151 | ||
4152 | void mem_cgroup_uncharge_page(struct page *page) | |
4153 | { | |
4154 | /* early check. */ | |
4155 | if (page_mapped(page)) | |
4156 | return; | |
4157 | VM_BUG_ON_PAGE(page->mapping && !PageAnon(page), page); | |
4158 | /* | |
4159 | * If the page is in swap cache, uncharge should be deferred | |
4160 | * to the swap path, which also properly accounts swap usage | |
4161 | * and handles memcg lifetime. | |
4162 | * | |
4163 | * Note that this check is not stable and reclaim may add the | |
4164 | * page to swap cache at any time after this. However, if the | |
4165 | * page is not in swap cache by the time page->mapcount hits | |
4166 | * 0, there won't be any page table references to the swap | |
4167 | * slot, and reclaim will free it and not actually write the | |
4168 | * page to disk. | |
4169 | */ | |
4170 | if (PageSwapCache(page)) | |
4171 | return; | |
4172 | __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_ANON, false); | |
4173 | } | |
4174 | ||
4175 | void mem_cgroup_uncharge_cache_page(struct page *page) | |
4176 | { | |
4177 | VM_BUG_ON_PAGE(page_mapped(page), page); | |
4178 | VM_BUG_ON_PAGE(page->mapping, page); | |
4179 | __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE, false); | |
4180 | } | |
4181 | ||
4182 | /* | |
4183 | * Batch_start/batch_end is called in unmap_page_range/invlidate/trucate. | |
4184 | * In that cases, pages are freed continuously and we can expect pages | |
4185 | * are in the same memcg. All these calls itself limits the number of | |
4186 | * pages freed at once, then uncharge_start/end() is called properly. | |
4187 | * This may be called prural(2) times in a context, | |
4188 | */ | |
4189 | ||
4190 | void mem_cgroup_uncharge_start(void) | |
4191 | { | |
4192 | current->memcg_batch.do_batch++; | |
4193 | /* We can do nest. */ | |
4194 | if (current->memcg_batch.do_batch == 1) { | |
4195 | current->memcg_batch.memcg = NULL; | |
4196 | current->memcg_batch.nr_pages = 0; | |
4197 | current->memcg_batch.memsw_nr_pages = 0; | |
4198 | } | |
4199 | } | |
4200 | ||
4201 | void mem_cgroup_uncharge_end(void) | |
4202 | { | |
4203 | struct memcg_batch_info *batch = ¤t->memcg_batch; | |
4204 | ||
4205 | if (!batch->do_batch) | |
4206 | return; | |
4207 | ||
4208 | batch->do_batch--; | |
4209 | if (batch->do_batch) /* If stacked, do nothing. */ | |
4210 | return; | |
4211 | ||
4212 | if (!batch->memcg) | |
4213 | return; | |
4214 | /* | |
4215 | * This "batch->memcg" is valid without any css_get/put etc... | |
4216 | * bacause we hide charges behind us. | |
4217 | */ | |
4218 | if (batch->nr_pages) | |
4219 | res_counter_uncharge(&batch->memcg->res, | |
4220 | batch->nr_pages * PAGE_SIZE); | |
4221 | if (batch->memsw_nr_pages) | |
4222 | res_counter_uncharge(&batch->memcg->memsw, | |
4223 | batch->memsw_nr_pages * PAGE_SIZE); | |
4224 | memcg_oom_recover(batch->memcg); | |
4225 | /* forget this pointer (for sanity check) */ | |
4226 | batch->memcg = NULL; | |
4227 | } | |
4228 | ||
4229 | #ifdef CONFIG_SWAP | |
4230 | /* | |
4231 | * called after __delete_from_swap_cache() and drop "page" account. | |
4232 | * memcg information is recorded to swap_cgroup of "ent" | |
4233 | */ | |
4234 | void | |
4235 | mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout) | |
4236 | { | |
4237 | struct mem_cgroup *memcg; | |
4238 | int ctype = MEM_CGROUP_CHARGE_TYPE_SWAPOUT; | |
4239 | ||
4240 | if (!swapout) /* this was a swap cache but the swap is unused ! */ | |
4241 | ctype = MEM_CGROUP_CHARGE_TYPE_DROP; | |
4242 | ||
4243 | memcg = __mem_cgroup_uncharge_common(page, ctype, false); | |
4244 | ||
4245 | /* | |
4246 | * record memcg information, if swapout && memcg != NULL, | |
4247 | * css_get() was called in uncharge(). | |
4248 | */ | |
4249 | if (do_swap_account && swapout && memcg) | |
4250 | swap_cgroup_record(ent, mem_cgroup_id(memcg)); | |
4251 | } | |
4252 | #endif | |
4253 | ||
4254 | #ifdef CONFIG_MEMCG_SWAP | |
4255 | /* | |
4256 | * called from swap_entry_free(). remove record in swap_cgroup and | |
4257 | * uncharge "memsw" account. | |
4258 | */ | |
4259 | void mem_cgroup_uncharge_swap(swp_entry_t ent) | |
4260 | { | |
4261 | struct mem_cgroup *memcg; | |
4262 | unsigned short id; | |
4263 | ||
4264 | if (!do_swap_account) | |
4265 | return; | |
4266 | ||
4267 | id = swap_cgroup_record(ent, 0); | |
4268 | rcu_read_lock(); | |
4269 | memcg = mem_cgroup_lookup(id); | |
4270 | if (memcg) { | |
4271 | /* | |
4272 | * We uncharge this because swap is freed. | |
4273 | * This memcg can be obsolete one. We avoid calling css_tryget | |
4274 | */ | |
4275 | if (!mem_cgroup_is_root(memcg)) | |
4276 | res_counter_uncharge(&memcg->memsw, PAGE_SIZE); | |
4277 | mem_cgroup_swap_statistics(memcg, false); | |
4278 | css_put(&memcg->css); | |
4279 | } | |
4280 | rcu_read_unlock(); | |
4281 | } | |
4282 | ||
4283 | /** | |
4284 | * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record. | |
4285 | * @entry: swap entry to be moved | |
4286 | * @from: mem_cgroup which the entry is moved from | |
4287 | * @to: mem_cgroup which the entry is moved to | |
4288 | * | |
4289 | * It succeeds only when the swap_cgroup's record for this entry is the same | |
4290 | * as the mem_cgroup's id of @from. | |
4291 | * | |
4292 | * Returns 0 on success, -EINVAL on failure. | |
4293 | * | |
4294 | * The caller must have charged to @to, IOW, called res_counter_charge() about | |
4295 | * both res and memsw, and called css_get(). | |
4296 | */ | |
4297 | static int mem_cgroup_move_swap_account(swp_entry_t entry, | |
4298 | struct mem_cgroup *from, struct mem_cgroup *to) | |
4299 | { | |
4300 | unsigned short old_id, new_id; | |
4301 | ||
4302 | old_id = mem_cgroup_id(from); | |
4303 | new_id = mem_cgroup_id(to); | |
4304 | ||
4305 | if (swap_cgroup_cmpxchg(entry, old_id, new_id) == old_id) { | |
4306 | mem_cgroup_swap_statistics(from, false); | |
4307 | mem_cgroup_swap_statistics(to, true); | |
4308 | /* | |
4309 | * This function is only called from task migration context now. | |
4310 | * It postpones res_counter and refcount handling till the end | |
4311 | * of task migration(mem_cgroup_clear_mc()) for performance | |
4312 | * improvement. But we cannot postpone css_get(to) because if | |
4313 | * the process that has been moved to @to does swap-in, the | |
4314 | * refcount of @to might be decreased to 0. | |
4315 | * | |
4316 | * We are in attach() phase, so the cgroup is guaranteed to be | |
4317 | * alive, so we can just call css_get(). | |
4318 | */ | |
4319 | css_get(&to->css); | |
4320 | return 0; | |
4321 | } | |
4322 | return -EINVAL; | |
4323 | } | |
4324 | #else | |
4325 | static inline int mem_cgroup_move_swap_account(swp_entry_t entry, | |
4326 | struct mem_cgroup *from, struct mem_cgroup *to) | |
4327 | { | |
4328 | return -EINVAL; | |
4329 | } | |
4330 | #endif | |
4331 | ||
4332 | /* | |
4333 | * Before starting migration, account PAGE_SIZE to mem_cgroup that the old | |
4334 | * page belongs to. | |
4335 | */ | |
4336 | void mem_cgroup_prepare_migration(struct page *page, struct page *newpage, | |
4337 | struct mem_cgroup **memcgp) | |
4338 | { | |
4339 | struct mem_cgroup *memcg = NULL; | |
4340 | unsigned int nr_pages = 1; | |
4341 | struct page_cgroup *pc; | |
4342 | enum charge_type ctype; | |
4343 | ||
4344 | *memcgp = NULL; | |
4345 | ||
4346 | if (mem_cgroup_disabled()) | |
4347 | return; | |
4348 | ||
4349 | if (PageTransHuge(page)) | |
4350 | nr_pages <<= compound_order(page); | |
4351 | ||
4352 | pc = lookup_page_cgroup(page); | |
4353 | lock_page_cgroup(pc); | |
4354 | if (PageCgroupUsed(pc)) { | |
4355 | memcg = pc->mem_cgroup; | |
4356 | css_get(&memcg->css); | |
4357 | /* | |
4358 | * At migrating an anonymous page, its mapcount goes down | |
4359 | * to 0 and uncharge() will be called. But, even if it's fully | |
4360 | * unmapped, migration may fail and this page has to be | |
4361 | * charged again. We set MIGRATION flag here and delay uncharge | |
4362 | * until end_migration() is called | |
4363 | * | |
4364 | * Corner Case Thinking | |
4365 | * A) | |
4366 | * When the old page was mapped as Anon and it's unmap-and-freed | |
4367 | * while migration was ongoing. | |
4368 | * If unmap finds the old page, uncharge() of it will be delayed | |
4369 | * until end_migration(). If unmap finds a new page, it's | |
4370 | * uncharged when it make mapcount to be 1->0. If unmap code | |
4371 | * finds swap_migration_entry, the new page will not be mapped | |
4372 | * and end_migration() will find it(mapcount==0). | |
4373 | * | |
4374 | * B) | |
4375 | * When the old page was mapped but migraion fails, the kernel | |
4376 | * remaps it. A charge for it is kept by MIGRATION flag even | |
4377 | * if mapcount goes down to 0. We can do remap successfully | |
4378 | * without charging it again. | |
4379 | * | |
4380 | * C) | |
4381 | * The "old" page is under lock_page() until the end of | |
4382 | * migration, so, the old page itself will not be swapped-out. | |
4383 | * If the new page is swapped out before end_migraton, our | |
4384 | * hook to usual swap-out path will catch the event. | |
4385 | */ | |
4386 | if (PageAnon(page)) | |
4387 | SetPageCgroupMigration(pc); | |
4388 | } | |
4389 | unlock_page_cgroup(pc); | |
4390 | /* | |
4391 | * If the page is not charged at this point, | |
4392 | * we return here. | |
4393 | */ | |
4394 | if (!memcg) | |
4395 | return; | |
4396 | ||
4397 | *memcgp = memcg; | |
4398 | /* | |
4399 | * We charge new page before it's used/mapped. So, even if unlock_page() | |
4400 | * is called before end_migration, we can catch all events on this new | |
4401 | * page. In the case new page is migrated but not remapped, new page's | |
4402 | * mapcount will be finally 0 and we call uncharge in end_migration(). | |
4403 | */ | |
4404 | if (PageAnon(page)) | |
4405 | ctype = MEM_CGROUP_CHARGE_TYPE_ANON; | |
4406 | else | |
4407 | ctype = MEM_CGROUP_CHARGE_TYPE_CACHE; | |
4408 | /* | |
4409 | * The page is committed to the memcg, but it's not actually | |
4410 | * charged to the res_counter since we plan on replacing the | |
4411 | * old one and only one page is going to be left afterwards. | |
4412 | */ | |
4413 | __mem_cgroup_commit_charge(memcg, newpage, nr_pages, ctype, false); | |
4414 | } | |
4415 | ||
4416 | /* remove redundant charge if migration failed*/ | |
4417 | void mem_cgroup_end_migration(struct mem_cgroup *memcg, | |
4418 | struct page *oldpage, struct page *newpage, bool migration_ok) | |
4419 | { | |
4420 | struct page *used, *unused; | |
4421 | struct page_cgroup *pc; | |
4422 | bool anon; | |
4423 | ||
4424 | if (!memcg) | |
4425 | return; | |
4426 | ||
4427 | if (!migration_ok) { | |
4428 | used = oldpage; | |
4429 | unused = newpage; | |
4430 | } else { | |
4431 | used = newpage; | |
4432 | unused = oldpage; | |
4433 | } | |
4434 | anon = PageAnon(used); | |
4435 | __mem_cgroup_uncharge_common(unused, | |
4436 | anon ? MEM_CGROUP_CHARGE_TYPE_ANON | |
4437 | : MEM_CGROUP_CHARGE_TYPE_CACHE, | |
4438 | true); | |
4439 | css_put(&memcg->css); | |
4440 | /* | |
4441 | * We disallowed uncharge of pages under migration because mapcount | |
4442 | * of the page goes down to zero, temporarly. | |
4443 | * Clear the flag and check the page should be charged. | |
4444 | */ | |
4445 | pc = lookup_page_cgroup(oldpage); | |
4446 | lock_page_cgroup(pc); | |
4447 | ClearPageCgroupMigration(pc); | |
4448 | unlock_page_cgroup(pc); | |
4449 | ||
4450 | /* | |
4451 | * If a page is a file cache, radix-tree replacement is very atomic | |
4452 | * and we can skip this check. When it was an Anon page, its mapcount | |
4453 | * goes down to 0. But because we added MIGRATION flage, it's not | |
4454 | * uncharged yet. There are several case but page->mapcount check | |
4455 | * and USED bit check in mem_cgroup_uncharge_page() will do enough | |
4456 | * check. (see prepare_charge() also) | |
4457 | */ | |
4458 | if (anon) | |
4459 | mem_cgroup_uncharge_page(used); | |
4460 | } | |
4461 | ||
4462 | /* | |
4463 | * At replace page cache, newpage is not under any memcg but it's on | |
4464 | * LRU. So, this function doesn't touch res_counter but handles LRU | |
4465 | * in correct way. Both pages are locked so we cannot race with uncharge. | |
4466 | */ | |
4467 | void mem_cgroup_replace_page_cache(struct page *oldpage, | |
4468 | struct page *newpage) | |
4469 | { | |
4470 | struct mem_cgroup *memcg = NULL; | |
4471 | struct page_cgroup *pc; | |
4472 | enum charge_type type = MEM_CGROUP_CHARGE_TYPE_CACHE; | |
4473 | ||
4474 | if (mem_cgroup_disabled()) | |
4475 | return; | |
4476 | ||
4477 | pc = lookup_page_cgroup(oldpage); | |
4478 | /* fix accounting on old pages */ | |
4479 | lock_page_cgroup(pc); | |
4480 | if (PageCgroupUsed(pc)) { | |
4481 | memcg = pc->mem_cgroup; | |
4482 | mem_cgroup_charge_statistics(memcg, oldpage, false, -1); | |
4483 | ClearPageCgroupUsed(pc); | |
4484 | } | |
4485 | unlock_page_cgroup(pc); | |
4486 | ||
4487 | /* | |
4488 | * When called from shmem_replace_page(), in some cases the | |
4489 | * oldpage has already been charged, and in some cases not. | |
4490 | */ | |
4491 | if (!memcg) | |
4492 | return; | |
4493 | /* | |
4494 | * Even if newpage->mapping was NULL before starting replacement, | |
4495 | * the newpage may be on LRU(or pagevec for LRU) already. We lock | |
4496 | * LRU while we overwrite pc->mem_cgroup. | |
4497 | */ | |
4498 | __mem_cgroup_commit_charge(memcg, newpage, 1, type, true); | |
4499 | } | |
4500 | ||
4501 | #ifdef CONFIG_DEBUG_VM | |
4502 | static struct page_cgroup *lookup_page_cgroup_used(struct page *page) | |
4503 | { | |
4504 | struct page_cgroup *pc; | |
4505 | ||
4506 | pc = lookup_page_cgroup(page); | |
4507 | /* | |
4508 | * Can be NULL while feeding pages into the page allocator for | |
4509 | * the first time, i.e. during boot or memory hotplug; | |
4510 | * or when mem_cgroup_disabled(). | |
4511 | */ | |
4512 | if (likely(pc) && PageCgroupUsed(pc)) | |
4513 | return pc; | |
4514 | return NULL; | |
4515 | } | |
4516 | ||
4517 | bool mem_cgroup_bad_page_check(struct page *page) | |
4518 | { | |
4519 | if (mem_cgroup_disabled()) | |
4520 | return false; | |
4521 | ||
4522 | return lookup_page_cgroup_used(page) != NULL; | |
4523 | } | |
4524 | ||
4525 | void mem_cgroup_print_bad_page(struct page *page) | |
4526 | { | |
4527 | struct page_cgroup *pc; | |
4528 | ||
4529 | pc = lookup_page_cgroup_used(page); | |
4530 | if (pc) { | |
4531 | pr_alert("pc:%p pc->flags:%lx pc->mem_cgroup:%p\n", | |
4532 | pc, pc->flags, pc->mem_cgroup); | |
4533 | } | |
4534 | } | |
4535 | #endif | |
4536 | ||
4537 | static int mem_cgroup_resize_limit(struct mem_cgroup *memcg, | |
4538 | unsigned long long val) | |
4539 | { | |
4540 | int retry_count; | |
4541 | u64 memswlimit, memlimit; | |
4542 | int ret = 0; | |
4543 | int children = mem_cgroup_count_children(memcg); | |
4544 | u64 curusage, oldusage; | |
4545 | int enlarge; | |
4546 | ||
4547 | /* | |
4548 | * For keeping hierarchical_reclaim simple, how long we should retry | |
4549 | * is depends on callers. We set our retry-count to be function | |
4550 | * of # of children which we should visit in this loop. | |
4551 | */ | |
4552 | retry_count = MEM_CGROUP_RECLAIM_RETRIES * children; | |
4553 | ||
4554 | oldusage = res_counter_read_u64(&memcg->res, RES_USAGE); | |
4555 | ||
4556 | enlarge = 0; | |
4557 | while (retry_count) { | |
4558 | if (signal_pending(current)) { | |
4559 | ret = -EINTR; | |
4560 | break; | |
4561 | } | |
4562 | /* | |
4563 | * Rather than hide all in some function, I do this in | |
4564 | * open coded manner. You see what this really does. | |
4565 | * We have to guarantee memcg->res.limit <= memcg->memsw.limit. | |
4566 | */ | |
4567 | mutex_lock(&set_limit_mutex); | |
4568 | memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT); | |
4569 | if (memswlimit < val) { | |
4570 | ret = -EINVAL; | |
4571 | mutex_unlock(&set_limit_mutex); | |
4572 | break; | |
4573 | } | |
4574 | ||
4575 | memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT); | |
4576 | if (memlimit < val) | |
4577 | enlarge = 1; | |
4578 | ||
4579 | ret = res_counter_set_limit(&memcg->res, val); | |
4580 | if (!ret) { | |
4581 | if (memswlimit == val) | |
4582 | memcg->memsw_is_minimum = true; | |
4583 | else | |
4584 | memcg->memsw_is_minimum = false; | |
4585 | } | |
4586 | mutex_unlock(&set_limit_mutex); | |
4587 | ||
4588 | if (!ret) | |
4589 | break; | |
4590 | ||
4591 | mem_cgroup_reclaim(memcg, GFP_KERNEL, | |
4592 | MEM_CGROUP_RECLAIM_SHRINK); | |
4593 | curusage = res_counter_read_u64(&memcg->res, RES_USAGE); | |
4594 | /* Usage is reduced ? */ | |
4595 | if (curusage >= oldusage) | |
4596 | retry_count--; | |
4597 | else | |
4598 | oldusage = curusage; | |
4599 | } | |
4600 | if (!ret && enlarge) | |
4601 | memcg_oom_recover(memcg); | |
4602 | ||
4603 | return ret; | |
4604 | } | |
4605 | ||
4606 | static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg, | |
4607 | unsigned long long val) | |
4608 | { | |
4609 | int retry_count; | |
4610 | u64 memlimit, memswlimit, oldusage, curusage; | |
4611 | int children = mem_cgroup_count_children(memcg); | |
4612 | int ret = -EBUSY; | |
4613 | int enlarge = 0; | |
4614 | ||
4615 | /* see mem_cgroup_resize_res_limit */ | |
4616 | retry_count = children * MEM_CGROUP_RECLAIM_RETRIES; | |
4617 | oldusage = res_counter_read_u64(&memcg->memsw, RES_USAGE); | |
4618 | while (retry_count) { | |
4619 | if (signal_pending(current)) { | |
4620 | ret = -EINTR; | |
4621 | break; | |
4622 | } | |
4623 | /* | |
4624 | * Rather than hide all in some function, I do this in | |
4625 | * open coded manner. You see what this really does. | |
4626 | * We have to guarantee memcg->res.limit <= memcg->memsw.limit. | |
4627 | */ | |
4628 | mutex_lock(&set_limit_mutex); | |
4629 | memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT); | |
4630 | if (memlimit > val) { | |
4631 | ret = -EINVAL; | |
4632 | mutex_unlock(&set_limit_mutex); | |
4633 | break; | |
4634 | } | |
4635 | memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT); | |
4636 | if (memswlimit < val) | |
4637 | enlarge = 1; | |
4638 | ret = res_counter_set_limit(&memcg->memsw, val); | |
4639 | if (!ret) { | |
4640 | if (memlimit == val) | |
4641 | memcg->memsw_is_minimum = true; | |
4642 | else | |
4643 | memcg->memsw_is_minimum = false; | |
4644 | } | |
4645 | mutex_unlock(&set_limit_mutex); | |
4646 | ||
4647 | if (!ret) | |
4648 | break; | |
4649 | ||
4650 | mem_cgroup_reclaim(memcg, GFP_KERNEL, | |
4651 | MEM_CGROUP_RECLAIM_NOSWAP | | |
4652 | MEM_CGROUP_RECLAIM_SHRINK); | |
4653 | curusage = res_counter_read_u64(&memcg->memsw, RES_USAGE); | |
4654 | /* Usage is reduced ? */ | |
4655 | if (curusage >= oldusage) | |
4656 | retry_count--; | |
4657 | else | |
4658 | oldusage = curusage; | |
4659 | } | |
4660 | if (!ret && enlarge) | |
4661 | memcg_oom_recover(memcg); | |
4662 | return ret; | |
4663 | } | |
4664 | ||
4665 | unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order, | |
4666 | gfp_t gfp_mask, | |
4667 | unsigned long *total_scanned) | |
4668 | { | |
4669 | unsigned long nr_reclaimed = 0; | |
4670 | struct mem_cgroup_per_zone *mz, *next_mz = NULL; | |
4671 | unsigned long reclaimed; | |
4672 | int loop = 0; | |
4673 | struct mem_cgroup_tree_per_zone *mctz; | |
4674 | unsigned long long excess; | |
4675 | unsigned long nr_scanned; | |
4676 | ||
4677 | if (order > 0) | |
4678 | return 0; | |
4679 | ||
4680 | mctz = soft_limit_tree_node_zone(zone_to_nid(zone), zone_idx(zone)); | |
4681 | /* | |
4682 | * This loop can run a while, specially if mem_cgroup's continuously | |
4683 | * keep exceeding their soft limit and putting the system under | |
4684 | * pressure | |
4685 | */ | |
4686 | do { | |
4687 | if (next_mz) | |
4688 | mz = next_mz; | |
4689 | else | |
4690 | mz = mem_cgroup_largest_soft_limit_node(mctz); | |
4691 | if (!mz) | |
4692 | break; | |
4693 | ||
4694 | nr_scanned = 0; | |
4695 | reclaimed = mem_cgroup_soft_reclaim(mz->memcg, zone, | |
4696 | gfp_mask, &nr_scanned); | |
4697 | nr_reclaimed += reclaimed; | |
4698 | *total_scanned += nr_scanned; | |
4699 | spin_lock(&mctz->lock); | |
4700 | ||
4701 | /* | |
4702 | * If we failed to reclaim anything from this memory cgroup | |
4703 | * it is time to move on to the next cgroup | |
4704 | */ | |
4705 | next_mz = NULL; | |
4706 | if (!reclaimed) { | |
4707 | do { | |
4708 | /* | |
4709 | * Loop until we find yet another one. | |
4710 | * | |
4711 | * By the time we get the soft_limit lock | |
4712 | * again, someone might have aded the | |
4713 | * group back on the RB tree. Iterate to | |
4714 | * make sure we get a different mem. | |
4715 | * mem_cgroup_largest_soft_limit_node returns | |
4716 | * NULL if no other cgroup is present on | |
4717 | * the tree | |
4718 | */ | |
4719 | next_mz = | |
4720 | __mem_cgroup_largest_soft_limit_node(mctz); | |
4721 | if (next_mz == mz) | |
4722 | css_put(&next_mz->memcg->css); | |
4723 | else /* next_mz == NULL or other memcg */ | |
4724 | break; | |
4725 | } while (1); | |
4726 | } | |
4727 | __mem_cgroup_remove_exceeded(mz->memcg, mz, mctz); | |
4728 | excess = res_counter_soft_limit_excess(&mz->memcg->res); | |
4729 | /* | |
4730 | * One school of thought says that we should not add | |
4731 | * back the node to the tree if reclaim returns 0. | |
4732 | * But our reclaim could return 0, simply because due | |
4733 | * to priority we are exposing a smaller subset of | |
4734 | * memory to reclaim from. Consider this as a longer | |
4735 | * term TODO. | |
4736 | */ | |
4737 | /* If excess == 0, no tree ops */ | |
4738 | __mem_cgroup_insert_exceeded(mz->memcg, mz, mctz, excess); | |
4739 | spin_unlock(&mctz->lock); | |
4740 | css_put(&mz->memcg->css); | |
4741 | loop++; | |
4742 | /* | |
4743 | * Could not reclaim anything and there are no more | |
4744 | * mem cgroups to try or we seem to be looping without | |
4745 | * reclaiming anything. | |
4746 | */ | |
4747 | if (!nr_reclaimed && | |
4748 | (next_mz == NULL || | |
4749 | loop > MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS)) | |
4750 | break; | |
4751 | } while (!nr_reclaimed); | |
4752 | if (next_mz) | |
4753 | css_put(&next_mz->memcg->css); | |
4754 | return nr_reclaimed; | |
4755 | } | |
4756 | ||
4757 | /** | |
4758 | * mem_cgroup_force_empty_list - clears LRU of a group | |
4759 | * @memcg: group to clear | |
4760 | * @node: NUMA node | |
4761 | * @zid: zone id | |
4762 | * @lru: lru to to clear | |
4763 | * | |
4764 | * Traverse a specified page_cgroup list and try to drop them all. This doesn't | |
4765 | * reclaim the pages page themselves - pages are moved to the parent (or root) | |
4766 | * group. | |
4767 | */ | |
4768 | static void mem_cgroup_force_empty_list(struct mem_cgroup *memcg, | |
4769 | int node, int zid, enum lru_list lru) | |
4770 | { | |
4771 | struct lruvec *lruvec; | |
4772 | unsigned long flags; | |
4773 | struct list_head *list; | |
4774 | struct page *busy; | |
4775 | struct zone *zone; | |
4776 | ||
4777 | zone = &NODE_DATA(node)->node_zones[zid]; | |
4778 | lruvec = mem_cgroup_zone_lruvec(zone, memcg); | |
4779 | list = &lruvec->lists[lru]; | |
4780 | ||
4781 | busy = NULL; | |
4782 | do { | |
4783 | struct page_cgroup *pc; | |
4784 | struct page *page; | |
4785 | ||
4786 | spin_lock_irqsave(&zone->lru_lock, flags); | |
4787 | if (list_empty(list)) { | |
4788 | spin_unlock_irqrestore(&zone->lru_lock, flags); | |
4789 | break; | |
4790 | } | |
4791 | page = list_entry(list->prev, struct page, lru); | |
4792 | if (busy == page) { | |
4793 | list_move(&page->lru, list); | |
4794 | busy = NULL; | |
4795 | spin_unlock_irqrestore(&zone->lru_lock, flags); | |
4796 | continue; | |
4797 | } | |
4798 | spin_unlock_irqrestore(&zone->lru_lock, flags); | |
4799 | ||
4800 | pc = lookup_page_cgroup(page); | |
4801 | ||
4802 | if (mem_cgroup_move_parent(page, pc, memcg)) { | |
4803 | /* found lock contention or "pc" is obsolete. */ | |
4804 | busy = page; | |
4805 | cond_resched(); | |
4806 | } else | |
4807 | busy = NULL; | |
4808 | } while (!list_empty(list)); | |
4809 | } | |
4810 | ||
4811 | /* | |
4812 | * make mem_cgroup's charge to be 0 if there is no task by moving | |
4813 | * all the charges and pages to the parent. | |
4814 | * This enables deleting this mem_cgroup. | |
4815 | * | |
4816 | * Caller is responsible for holding css reference on the memcg. | |
4817 | */ | |
4818 | static void mem_cgroup_reparent_charges(struct mem_cgroup *memcg) | |
4819 | { | |
4820 | int node, zid; | |
4821 | u64 usage; | |
4822 | ||
4823 | do { | |
4824 | /* This is for making all *used* pages to be on LRU. */ | |
4825 | lru_add_drain_all(); | |
4826 | drain_all_stock_sync(memcg); | |
4827 | mem_cgroup_start_move(memcg); | |
4828 | for_each_node_state(node, N_MEMORY) { | |
4829 | for (zid = 0; zid < MAX_NR_ZONES; zid++) { | |
4830 | enum lru_list lru; | |
4831 | for_each_lru(lru) { | |
4832 | mem_cgroup_force_empty_list(memcg, | |
4833 | node, zid, lru); | |
4834 | } | |
4835 | } | |
4836 | } | |
4837 | mem_cgroup_end_move(memcg); | |
4838 | memcg_oom_recover(memcg); | |
4839 | cond_resched(); | |
4840 | ||
4841 | /* | |
4842 | * Kernel memory may not necessarily be trackable to a specific | |
4843 | * process. So they are not migrated, and therefore we can't | |
4844 | * expect their value to drop to 0 here. | |
4845 | * Having res filled up with kmem only is enough. | |
4846 | * | |
4847 | * This is a safety check because mem_cgroup_force_empty_list | |
4848 | * could have raced with mem_cgroup_replace_page_cache callers | |
4849 | * so the lru seemed empty but the page could have been added | |
4850 | * right after the check. RES_USAGE should be safe as we always | |
4851 | * charge before adding to the LRU. | |
4852 | */ | |
4853 | usage = res_counter_read_u64(&memcg->res, RES_USAGE) - | |
4854 | res_counter_read_u64(&memcg->kmem, RES_USAGE); | |
4855 | } while (usage > 0); | |
4856 | } | |
4857 | ||
4858 | static inline bool memcg_has_children(struct mem_cgroup *memcg) | |
4859 | { | |
4860 | lockdep_assert_held(&memcg_create_mutex); | |
4861 | /* | |
4862 | * The lock does not prevent addition or deletion to the list | |
4863 | * of children, but it prevents a new child from being | |
4864 | * initialized based on this parent in css_online(), so it's | |
4865 | * enough to decide whether hierarchically inherited | |
4866 | * attributes can still be changed or not. | |
4867 | */ | |
4868 | return memcg->use_hierarchy && | |
4869 | !list_empty(&memcg->css.cgroup->children); | |
4870 | } | |
4871 | ||
4872 | /* | |
4873 | * Reclaims as many pages from the given memcg as possible and moves | |
4874 | * the rest to the parent. | |
4875 | * | |
4876 | * Caller is responsible for holding css reference for memcg. | |
4877 | */ | |
4878 | static int mem_cgroup_force_empty(struct mem_cgroup *memcg) | |
4879 | { | |
4880 | int nr_retries = MEM_CGROUP_RECLAIM_RETRIES; | |
4881 | struct cgroup *cgrp = memcg->css.cgroup; | |
4882 | ||
4883 | /* returns EBUSY if there is a task or if we come here twice. */ | |
4884 | if (cgroup_has_tasks(cgrp) || !list_empty(&cgrp->children)) | |
4885 | return -EBUSY; | |
4886 | ||
4887 | /* we call try-to-free pages for make this cgroup empty */ | |
4888 | lru_add_drain_all(); | |
4889 | /* try to free all pages in this cgroup */ | |
4890 | while (nr_retries && res_counter_read_u64(&memcg->res, RES_USAGE) > 0) { | |
4891 | int progress; | |
4892 | ||
4893 | if (signal_pending(current)) | |
4894 | return -EINTR; | |
4895 | ||
4896 | progress = try_to_free_mem_cgroup_pages(memcg, GFP_KERNEL, | |
4897 | false); | |
4898 | if (!progress) { | |
4899 | nr_retries--; | |
4900 | /* maybe some writeback is necessary */ | |
4901 | congestion_wait(BLK_RW_ASYNC, HZ/10); | |
4902 | } | |
4903 | ||
4904 | } | |
4905 | lru_add_drain(); | |
4906 | mem_cgroup_reparent_charges(memcg); | |
4907 | ||
4908 | return 0; | |
4909 | } | |
4910 | ||
4911 | static int mem_cgroup_force_empty_write(struct cgroup_subsys_state *css, | |
4912 | unsigned int event) | |
4913 | { | |
4914 | struct mem_cgroup *memcg = mem_cgroup_from_css(css); | |
4915 | ||
4916 | if (mem_cgroup_is_root(memcg)) | |
4917 | return -EINVAL; | |
4918 | return mem_cgroup_force_empty(memcg); | |
4919 | } | |
4920 | ||
4921 | static u64 mem_cgroup_hierarchy_read(struct cgroup_subsys_state *css, | |
4922 | struct cftype *cft) | |
4923 | { | |
4924 | return mem_cgroup_from_css(css)->use_hierarchy; | |
4925 | } | |
4926 | ||
4927 | static int mem_cgroup_hierarchy_write(struct cgroup_subsys_state *css, | |
4928 | struct cftype *cft, u64 val) | |
4929 | { | |
4930 | int retval = 0; | |
4931 | struct mem_cgroup *memcg = mem_cgroup_from_css(css); | |
4932 | struct mem_cgroup *parent_memcg = mem_cgroup_from_css(css_parent(&memcg->css)); | |
4933 | ||
4934 | mutex_lock(&memcg_create_mutex); | |
4935 | ||
4936 | if (memcg->use_hierarchy == val) | |
4937 | goto out; | |
4938 | ||
4939 | /* | |
4940 | * If parent's use_hierarchy is set, we can't make any modifications | |
4941 | * in the child subtrees. If it is unset, then the change can | |
4942 | * occur, provided the current cgroup has no children. | |
4943 | * | |
4944 | * For the root cgroup, parent_mem is NULL, we allow value to be | |
4945 | * set if there are no children. | |
4946 | */ | |
4947 | if ((!parent_memcg || !parent_memcg->use_hierarchy) && | |
4948 | (val == 1 || val == 0)) { | |
4949 | if (list_empty(&memcg->css.cgroup->children)) | |
4950 | memcg->use_hierarchy = val; | |
4951 | else | |
4952 | retval = -EBUSY; | |
4953 | } else | |
4954 | retval = -EINVAL; | |
4955 | ||
4956 | out: | |
4957 | mutex_unlock(&memcg_create_mutex); | |
4958 | ||
4959 | return retval; | |
4960 | } | |
4961 | ||
4962 | ||
4963 | static unsigned long mem_cgroup_recursive_stat(struct mem_cgroup *memcg, | |
4964 | enum mem_cgroup_stat_index idx) | |
4965 | { | |
4966 | struct mem_cgroup *iter; | |
4967 | long val = 0; | |
4968 | ||
4969 | /* Per-cpu values can be negative, use a signed accumulator */ | |
4970 | for_each_mem_cgroup_tree(iter, memcg) | |
4971 | val += mem_cgroup_read_stat(iter, idx); | |
4972 | ||
4973 | if (val < 0) /* race ? */ | |
4974 | val = 0; | |
4975 | return val; | |
4976 | } | |
4977 | ||
4978 | static inline u64 mem_cgroup_usage(struct mem_cgroup *memcg, bool swap) | |
4979 | { | |
4980 | u64 val; | |
4981 | ||
4982 | if (!mem_cgroup_is_root(memcg)) { | |
4983 | if (!swap) | |
4984 | return res_counter_read_u64(&memcg->res, RES_USAGE); | |
4985 | else | |
4986 | return res_counter_read_u64(&memcg->memsw, RES_USAGE); | |
4987 | } | |
4988 | ||
4989 | /* | |
4990 | * Transparent hugepages are still accounted for in MEM_CGROUP_STAT_RSS | |
4991 | * as well as in MEM_CGROUP_STAT_RSS_HUGE. | |
4992 | */ | |
4993 | val = mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_CACHE); | |
4994 | val += mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_RSS); | |
4995 | ||
4996 | if (swap) | |
4997 | val += mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_SWAP); | |
4998 | ||
4999 | return val << PAGE_SHIFT; | |
5000 | } | |
5001 | ||
5002 | static u64 mem_cgroup_read_u64(struct cgroup_subsys_state *css, | |
5003 | struct cftype *cft) | |
5004 | { | |
5005 | struct mem_cgroup *memcg = mem_cgroup_from_css(css); | |
5006 | u64 val; | |
5007 | int name; | |
5008 | enum res_type type; | |
5009 | ||
5010 | type = MEMFILE_TYPE(cft->private); | |
5011 | name = MEMFILE_ATTR(cft->private); | |
5012 | ||
5013 | switch (type) { | |
5014 | case _MEM: | |
5015 | if (name == RES_USAGE) | |
5016 | val = mem_cgroup_usage(memcg, false); | |
5017 | else | |
5018 | val = res_counter_read_u64(&memcg->res, name); | |
5019 | break; | |
5020 | case _MEMSWAP: | |
5021 | if (name == RES_USAGE) | |
5022 | val = mem_cgroup_usage(memcg, true); | |
5023 | else | |
5024 | val = res_counter_read_u64(&memcg->memsw, name); | |
5025 | break; | |
5026 | case _KMEM: | |
5027 | val = res_counter_read_u64(&memcg->kmem, name); | |
5028 | break; | |
5029 | default: | |
5030 | BUG(); | |
5031 | } | |
5032 | ||
5033 | return val; | |
5034 | } | |
5035 | ||
5036 | #ifdef CONFIG_MEMCG_KMEM | |
5037 | /* should be called with activate_kmem_mutex held */ | |
5038 | static int __memcg_activate_kmem(struct mem_cgroup *memcg, | |
5039 | unsigned long long limit) | |
5040 | { | |
5041 | int err = 0; | |
5042 | int memcg_id; | |
5043 | ||
5044 | if (memcg_kmem_is_active(memcg)) | |
5045 | return 0; | |
5046 | ||
5047 | /* | |
5048 | * We are going to allocate memory for data shared by all memory | |
5049 | * cgroups so let's stop accounting here. | |
5050 | */ | |
5051 | memcg_stop_kmem_account(); | |
5052 | ||
5053 | /* | |
5054 | * For simplicity, we won't allow this to be disabled. It also can't | |
5055 | * be changed if the cgroup has children already, or if tasks had | |
5056 | * already joined. | |
5057 | * | |
5058 | * If tasks join before we set the limit, a person looking at | |
5059 | * kmem.usage_in_bytes will have no way to determine when it took | |
5060 | * place, which makes the value quite meaningless. | |
5061 | * | |
5062 | * After it first became limited, changes in the value of the limit are | |
5063 | * of course permitted. | |
5064 | */ | |
5065 | mutex_lock(&memcg_create_mutex); | |
5066 | if (cgroup_has_tasks(memcg->css.cgroup) || memcg_has_children(memcg)) | |
5067 | err = -EBUSY; | |
5068 | mutex_unlock(&memcg_create_mutex); | |
5069 | if (err) | |
5070 | goto out; | |
5071 | ||
5072 | memcg_id = ida_simple_get(&kmem_limited_groups, | |
5073 | 0, MEMCG_CACHES_MAX_SIZE, GFP_KERNEL); | |
5074 | if (memcg_id < 0) { | |
5075 | err = memcg_id; | |
5076 | goto out; | |
5077 | } | |
5078 | ||
5079 | /* | |
5080 | * Make sure we have enough space for this cgroup in each root cache's | |
5081 | * memcg_params. | |
5082 | */ | |
5083 | err = memcg_update_all_caches(memcg_id + 1); | |
5084 | if (err) | |
5085 | goto out_rmid; | |
5086 | ||
5087 | memcg->kmemcg_id = memcg_id; | |
5088 | INIT_LIST_HEAD(&memcg->memcg_slab_caches); | |
5089 | mutex_init(&memcg->slab_caches_mutex); | |
5090 | ||
5091 | /* | |
5092 | * We couldn't have accounted to this cgroup, because it hasn't got the | |
5093 | * active bit set yet, so this should succeed. | |
5094 | */ | |
5095 | err = res_counter_set_limit(&memcg->kmem, limit); | |
5096 | VM_BUG_ON(err); | |
5097 | ||
5098 | static_key_slow_inc(&memcg_kmem_enabled_key); | |
5099 | /* | |
5100 | * Setting the active bit after enabling static branching will | |
5101 | * guarantee no one starts accounting before all call sites are | |
5102 | * patched. | |
5103 | */ | |
5104 | memcg_kmem_set_active(memcg); | |
5105 | out: | |
5106 | memcg_resume_kmem_account(); | |
5107 | return err; | |
5108 | ||
5109 | out_rmid: | |
5110 | ida_simple_remove(&kmem_limited_groups, memcg_id); | |
5111 | goto out; | |
5112 | } | |
5113 | ||
5114 | static int memcg_activate_kmem(struct mem_cgroup *memcg, | |
5115 | unsigned long long limit) | |
5116 | { | |
5117 | int ret; | |
5118 | ||
5119 | mutex_lock(&activate_kmem_mutex); | |
5120 | ret = __memcg_activate_kmem(memcg, limit); | |
5121 | mutex_unlock(&activate_kmem_mutex); | |
5122 | return ret; | |
5123 | } | |
5124 | ||
5125 | static int memcg_update_kmem_limit(struct mem_cgroup *memcg, | |
5126 | unsigned long long val) | |
5127 | { | |
5128 | int ret; | |
5129 | ||
5130 | if (!memcg_kmem_is_active(memcg)) | |
5131 | ret = memcg_activate_kmem(memcg, val); | |
5132 | else | |
5133 | ret = res_counter_set_limit(&memcg->kmem, val); | |
5134 | return ret; | |
5135 | } | |
5136 | ||
5137 | static int memcg_propagate_kmem(struct mem_cgroup *memcg) | |
5138 | { | |
5139 | int ret = 0; | |
5140 | struct mem_cgroup *parent = parent_mem_cgroup(memcg); | |
5141 | ||
5142 | if (!parent) | |
5143 | return 0; | |
5144 | ||
5145 | mutex_lock(&activate_kmem_mutex); | |
5146 | /* | |
5147 | * If the parent cgroup is not kmem-active now, it cannot be activated | |
5148 | * after this point, because it has at least one child already. | |
5149 | */ | |
5150 | if (memcg_kmem_is_active(parent)) | |
5151 | ret = __memcg_activate_kmem(memcg, RES_COUNTER_MAX); | |
5152 | mutex_unlock(&activate_kmem_mutex); | |
5153 | return ret; | |
5154 | } | |
5155 | #else | |
5156 | static int memcg_update_kmem_limit(struct mem_cgroup *memcg, | |
5157 | unsigned long long val) | |
5158 | { | |
5159 | return -EINVAL; | |
5160 | } | |
5161 | #endif /* CONFIG_MEMCG_KMEM */ | |
5162 | ||
5163 | /* | |
5164 | * The user of this function is... | |
5165 | * RES_LIMIT. | |
5166 | */ | |
5167 | static int mem_cgroup_write(struct cgroup_subsys_state *css, struct cftype *cft, | |
5168 | char *buffer) | |
5169 | { | |
5170 | struct mem_cgroup *memcg = mem_cgroup_from_css(css); | |
5171 | enum res_type type; | |
5172 | int name; | |
5173 | unsigned long long val; | |
5174 | int ret; | |
5175 | ||
5176 | type = MEMFILE_TYPE(cft->private); | |
5177 | name = MEMFILE_ATTR(cft->private); | |
5178 | ||
5179 | switch (name) { | |
5180 | case RES_LIMIT: | |
5181 | if (mem_cgroup_is_root(memcg)) { /* Can't set limit on root */ | |
5182 | ret = -EINVAL; | |
5183 | break; | |
5184 | } | |
5185 | /* This function does all necessary parse...reuse it */ | |
5186 | ret = res_counter_memparse_write_strategy(buffer, &val); | |
5187 | if (ret) | |
5188 | break; | |
5189 | if (type == _MEM) | |
5190 | ret = mem_cgroup_resize_limit(memcg, val); | |
5191 | else if (type == _MEMSWAP) | |
5192 | ret = mem_cgroup_resize_memsw_limit(memcg, val); | |
5193 | else if (type == _KMEM) | |
5194 | ret = memcg_update_kmem_limit(memcg, val); | |
5195 | else | |
5196 | return -EINVAL; | |
5197 | break; | |
5198 | case RES_SOFT_LIMIT: | |
5199 | ret = res_counter_memparse_write_strategy(buffer, &val); | |
5200 | if (ret) | |
5201 | break; | |
5202 | /* | |
5203 | * For memsw, soft limits are hard to implement in terms | |
5204 | * of semantics, for now, we support soft limits for | |
5205 | * control without swap | |
5206 | */ | |
5207 | if (type == _MEM) | |
5208 | ret = res_counter_set_soft_limit(&memcg->res, val); | |
5209 | else | |
5210 | ret = -EINVAL; | |
5211 | break; | |
5212 | default: | |
5213 | ret = -EINVAL; /* should be BUG() ? */ | |
5214 | break; | |
5215 | } | |
5216 | return ret; | |
5217 | } | |
5218 | ||
5219 | static void memcg_get_hierarchical_limit(struct mem_cgroup *memcg, | |
5220 | unsigned long long *mem_limit, unsigned long long *memsw_limit) | |
5221 | { | |
5222 | unsigned long long min_limit, min_memsw_limit, tmp; | |
5223 | ||
5224 | min_limit = res_counter_read_u64(&memcg->res, RES_LIMIT); | |
5225 | min_memsw_limit = res_counter_read_u64(&memcg->memsw, RES_LIMIT); | |
5226 | if (!memcg->use_hierarchy) | |
5227 | goto out; | |
5228 | ||
5229 | while (css_parent(&memcg->css)) { | |
5230 | memcg = mem_cgroup_from_css(css_parent(&memcg->css)); | |
5231 | if (!memcg->use_hierarchy) | |
5232 | break; | |
5233 | tmp = res_counter_read_u64(&memcg->res, RES_LIMIT); | |
5234 | min_limit = min(min_limit, tmp); | |
5235 | tmp = res_counter_read_u64(&memcg->memsw, RES_LIMIT); | |
5236 | min_memsw_limit = min(min_memsw_limit, tmp); | |
5237 | } | |
5238 | out: | |
5239 | *mem_limit = min_limit; | |
5240 | *memsw_limit = min_memsw_limit; | |
5241 | } | |
5242 | ||
5243 | static int mem_cgroup_reset(struct cgroup_subsys_state *css, unsigned int event) | |
5244 | { | |
5245 | struct mem_cgroup *memcg = mem_cgroup_from_css(css); | |
5246 | int name; | |
5247 | enum res_type type; | |
5248 | ||
5249 | type = MEMFILE_TYPE(event); | |
5250 | name = MEMFILE_ATTR(event); | |
5251 | ||
5252 | switch (name) { | |
5253 | case RES_MAX_USAGE: | |
5254 | if (type == _MEM) | |
5255 | res_counter_reset_max(&memcg->res); | |
5256 | else if (type == _MEMSWAP) | |
5257 | res_counter_reset_max(&memcg->memsw); | |
5258 | else if (type == _KMEM) | |
5259 | res_counter_reset_max(&memcg->kmem); | |
5260 | else | |
5261 | return -EINVAL; | |
5262 | break; | |
5263 | case RES_FAILCNT: | |
5264 | if (type == _MEM) | |
5265 | res_counter_reset_failcnt(&memcg->res); | |
5266 | else if (type == _MEMSWAP) | |
5267 | res_counter_reset_failcnt(&memcg->memsw); | |
5268 | else if (type == _KMEM) | |
5269 | res_counter_reset_failcnt(&memcg->kmem); | |
5270 | else | |
5271 | return -EINVAL; | |
5272 | break; | |
5273 | } | |
5274 | ||
5275 | return 0; | |
5276 | } | |
5277 | ||
5278 | static u64 mem_cgroup_move_charge_read(struct cgroup_subsys_state *css, | |
5279 | struct cftype *cft) | |
5280 | { | |
5281 | return mem_cgroup_from_css(css)->move_charge_at_immigrate; | |
5282 | } | |
5283 | ||
5284 | #ifdef CONFIG_MMU | |
5285 | static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css, | |
5286 | struct cftype *cft, u64 val) | |
5287 | { | |
5288 | struct mem_cgroup *memcg = mem_cgroup_from_css(css); | |
5289 | ||
5290 | if (val >= (1 << NR_MOVE_TYPE)) | |
5291 | return -EINVAL; | |
5292 | ||
5293 | /* | |
5294 | * No kind of locking is needed in here, because ->can_attach() will | |
5295 | * check this value once in the beginning of the process, and then carry | |
5296 | * on with stale data. This means that changes to this value will only | |
5297 | * affect task migrations starting after the change. | |
5298 | */ | |
5299 | memcg->move_charge_at_immigrate = val; | |
5300 | return 0; | |
5301 | } | |
5302 | #else | |
5303 | static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css, | |
5304 | struct cftype *cft, u64 val) | |
5305 | { | |
5306 | return -ENOSYS; | |
5307 | } | |
5308 | #endif | |
5309 | ||
5310 | #ifdef CONFIG_NUMA | |
5311 | static int memcg_numa_stat_show(struct seq_file *m, void *v) | |
5312 | { | |
5313 | struct numa_stat { | |
5314 | const char *name; | |
5315 | unsigned int lru_mask; | |
5316 | }; | |
5317 | ||
5318 | static const struct numa_stat stats[] = { | |
5319 | { "total", LRU_ALL }, | |
5320 | { "file", LRU_ALL_FILE }, | |
5321 | { "anon", LRU_ALL_ANON }, | |
5322 | { "unevictable", BIT(LRU_UNEVICTABLE) }, | |
5323 | }; | |
5324 | const struct numa_stat *stat; | |
5325 | int nid; | |
5326 | unsigned long nr; | |
5327 | struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m)); | |
5328 | ||
5329 | for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) { | |
5330 | nr = mem_cgroup_nr_lru_pages(memcg, stat->lru_mask); | |
5331 | seq_printf(m, "%s=%lu", stat->name, nr); | |
5332 | for_each_node_state(nid, N_MEMORY) { | |
5333 | nr = mem_cgroup_node_nr_lru_pages(memcg, nid, | |
5334 | stat->lru_mask); | |
5335 | seq_printf(m, " N%d=%lu", nid, nr); | |
5336 | } | |
5337 | seq_putc(m, '\n'); | |
5338 | } | |
5339 | ||
5340 | for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) { | |
5341 | struct mem_cgroup *iter; | |
5342 | ||
5343 | nr = 0; | |
5344 | for_each_mem_cgroup_tree(iter, memcg) | |
5345 | nr += mem_cgroup_nr_lru_pages(iter, stat->lru_mask); | |
5346 | seq_printf(m, "hierarchical_%s=%lu", stat->name, nr); | |
5347 | for_each_node_state(nid, N_MEMORY) { | |
5348 | nr = 0; | |
5349 | for_each_mem_cgroup_tree(iter, memcg) | |
5350 | nr += mem_cgroup_node_nr_lru_pages( | |
5351 | iter, nid, stat->lru_mask); | |
5352 | seq_printf(m, " N%d=%lu", nid, nr); | |
5353 | } | |
5354 | seq_putc(m, '\n'); | |
5355 | } | |
5356 | ||
5357 | return 0; | |
5358 | } | |
5359 | #endif /* CONFIG_NUMA */ | |
5360 | ||
5361 | static inline void mem_cgroup_lru_names_not_uptodate(void) | |
5362 | { | |
5363 | BUILD_BUG_ON(ARRAY_SIZE(mem_cgroup_lru_names) != NR_LRU_LISTS); | |
5364 | } | |
5365 | ||
5366 | static int memcg_stat_show(struct seq_file *m, void *v) | |
5367 | { | |
5368 | struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m)); | |
5369 | struct mem_cgroup *mi; | |
5370 | unsigned int i; | |
5371 | ||
5372 | for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) { | |
5373 | if (i == MEM_CGROUP_STAT_SWAP && !do_swap_account) | |
5374 | continue; | |
5375 | seq_printf(m, "%s %ld\n", mem_cgroup_stat_names[i], | |
5376 | mem_cgroup_read_stat(memcg, i) * PAGE_SIZE); | |
5377 | } | |
5378 | ||
5379 | for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++) | |
5380 | seq_printf(m, "%s %lu\n", mem_cgroup_events_names[i], | |
5381 | mem_cgroup_read_events(memcg, i)); | |
5382 | ||
5383 | for (i = 0; i < NR_LRU_LISTS; i++) | |
5384 | seq_printf(m, "%s %lu\n", mem_cgroup_lru_names[i], | |
5385 | mem_cgroup_nr_lru_pages(memcg, BIT(i)) * PAGE_SIZE); | |
5386 | ||
5387 | /* Hierarchical information */ | |
5388 | { | |
5389 | unsigned long long limit, memsw_limit; | |
5390 | memcg_get_hierarchical_limit(memcg, &limit, &memsw_limit); | |
5391 | seq_printf(m, "hierarchical_memory_limit %llu\n", limit); | |
5392 | if (do_swap_account) | |
5393 | seq_printf(m, "hierarchical_memsw_limit %llu\n", | |
5394 | memsw_limit); | |
5395 | } | |
5396 | ||
5397 | for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) { | |
5398 | long long val = 0; | |
5399 | ||
5400 | if (i == MEM_CGROUP_STAT_SWAP && !do_swap_account) | |
5401 | continue; | |
5402 | for_each_mem_cgroup_tree(mi, memcg) | |
5403 | val += mem_cgroup_read_stat(mi, i) * PAGE_SIZE; | |
5404 | seq_printf(m, "total_%s %lld\n", mem_cgroup_stat_names[i], val); | |
5405 | } | |
5406 | ||
5407 | for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++) { | |
5408 | unsigned long long val = 0; | |
5409 | ||
5410 | for_each_mem_cgroup_tree(mi, memcg) | |
5411 | val += mem_cgroup_read_events(mi, i); | |
5412 | seq_printf(m, "total_%s %llu\n", | |
5413 | mem_cgroup_events_names[i], val); | |
5414 | } | |
5415 | ||
5416 | for (i = 0; i < NR_LRU_LISTS; i++) { | |
5417 | unsigned long long val = 0; | |
5418 | ||
5419 | for_each_mem_cgroup_tree(mi, memcg) | |
5420 | val += mem_cgroup_nr_lru_pages(mi, BIT(i)) * PAGE_SIZE; | |
5421 | seq_printf(m, "total_%s %llu\n", mem_cgroup_lru_names[i], val); | |
5422 | } | |
5423 | ||
5424 | #ifdef CONFIG_DEBUG_VM | |
5425 | { | |
5426 | int nid, zid; | |
5427 | struct mem_cgroup_per_zone *mz; | |
5428 | struct zone_reclaim_stat *rstat; | |
5429 | unsigned long recent_rotated[2] = {0, 0}; | |
5430 | unsigned long recent_scanned[2] = {0, 0}; | |
5431 | ||
5432 | for_each_online_node(nid) | |
5433 | for (zid = 0; zid < MAX_NR_ZONES; zid++) { | |
5434 | mz = mem_cgroup_zoneinfo(memcg, nid, zid); | |
5435 | rstat = &mz->lruvec.reclaim_stat; | |
5436 | ||
5437 | recent_rotated[0] += rstat->recent_rotated[0]; | |
5438 | recent_rotated[1] += rstat->recent_rotated[1]; | |
5439 | recent_scanned[0] += rstat->recent_scanned[0]; | |
5440 | recent_scanned[1] += rstat->recent_scanned[1]; | |
5441 | } | |
5442 | seq_printf(m, "recent_rotated_anon %lu\n", recent_rotated[0]); | |
5443 | seq_printf(m, "recent_rotated_file %lu\n", recent_rotated[1]); | |
5444 | seq_printf(m, "recent_scanned_anon %lu\n", recent_scanned[0]); | |
5445 | seq_printf(m, "recent_scanned_file %lu\n", recent_scanned[1]); | |
5446 | } | |
5447 | #endif | |
5448 | ||
5449 | return 0; | |
5450 | } | |
5451 | ||
5452 | static u64 mem_cgroup_swappiness_read(struct cgroup_subsys_state *css, | |
5453 | struct cftype *cft) | |
5454 | { | |
5455 | struct mem_cgroup *memcg = mem_cgroup_from_css(css); | |
5456 | ||
5457 | return mem_cgroup_swappiness(memcg); | |
5458 | } | |
5459 | ||
5460 | static int mem_cgroup_swappiness_write(struct cgroup_subsys_state *css, | |
5461 | struct cftype *cft, u64 val) | |
5462 | { | |
5463 | struct mem_cgroup *memcg = mem_cgroup_from_css(css); | |
5464 | struct mem_cgroup *parent = mem_cgroup_from_css(css_parent(&memcg->css)); | |
5465 | ||
5466 | if (val > 100 || !parent) | |
5467 | return -EINVAL; | |
5468 | ||
5469 | mutex_lock(&memcg_create_mutex); | |
5470 | ||
5471 | /* If under hierarchy, only empty-root can set this value */ | |
5472 | if ((parent->use_hierarchy) || memcg_has_children(memcg)) { | |
5473 | mutex_unlock(&memcg_create_mutex); | |
5474 | return -EINVAL; | |
5475 | } | |
5476 | ||
5477 | memcg->swappiness = val; | |
5478 | ||
5479 | mutex_unlock(&memcg_create_mutex); | |
5480 | ||
5481 | return 0; | |
5482 | } | |
5483 | ||
5484 | static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap) | |
5485 | { | |
5486 | struct mem_cgroup_threshold_ary *t; | |
5487 | u64 usage; | |
5488 | int i; | |
5489 | ||
5490 | rcu_read_lock(); | |
5491 | if (!swap) | |
5492 | t = rcu_dereference(memcg->thresholds.primary); | |
5493 | else | |
5494 | t = rcu_dereference(memcg->memsw_thresholds.primary); | |
5495 | ||
5496 | if (!t) | |
5497 | goto unlock; | |
5498 | ||
5499 | usage = mem_cgroup_usage(memcg, swap); | |
5500 | ||
5501 | /* | |
5502 | * current_threshold points to threshold just below or equal to usage. | |
5503 | * If it's not true, a threshold was crossed after last | |
5504 | * call of __mem_cgroup_threshold(). | |
5505 | */ | |
5506 | i = t->current_threshold; | |
5507 | ||
5508 | /* | |
5509 | * Iterate backward over array of thresholds starting from | |
5510 | * current_threshold and check if a threshold is crossed. | |
5511 | * If none of thresholds below usage is crossed, we read | |
5512 | * only one element of the array here. | |
5513 | */ | |
5514 | for (; i >= 0 && unlikely(t->entries[i].threshold > usage); i--) | |
5515 | eventfd_signal(t->entries[i].eventfd, 1); | |
5516 | ||
5517 | /* i = current_threshold + 1 */ | |
5518 | i++; | |
5519 | ||
5520 | /* | |
5521 | * Iterate forward over array of thresholds starting from | |
5522 | * current_threshold+1 and check if a threshold is crossed. | |
5523 | * If none of thresholds above usage is crossed, we read | |
5524 | * only one element of the array here. | |
5525 | */ | |
5526 | for (; i < t->size && unlikely(t->entries[i].threshold <= usage); i++) | |
5527 | eventfd_signal(t->entries[i].eventfd, 1); | |
5528 | ||
5529 | /* Update current_threshold */ | |
5530 | t->current_threshold = i - 1; | |
5531 | unlock: | |
5532 | rcu_read_unlock(); | |
5533 | } | |
5534 | ||
5535 | static void mem_cgroup_threshold(struct mem_cgroup *memcg) | |
5536 | { | |
5537 | while (memcg) { | |
5538 | __mem_cgroup_threshold(memcg, false); | |
5539 | if (do_swap_account) | |
5540 | __mem_cgroup_threshold(memcg, true); | |
5541 | ||
5542 | memcg = parent_mem_cgroup(memcg); | |
5543 | } | |
5544 | } | |
5545 | ||
5546 | static int compare_thresholds(const void *a, const void *b) | |
5547 | { | |
5548 | const struct mem_cgroup_threshold *_a = a; | |
5549 | const struct mem_cgroup_threshold *_b = b; | |
5550 | ||
5551 | if (_a->threshold > _b->threshold) | |
5552 | return 1; | |
5553 | ||
5554 | if (_a->threshold < _b->threshold) | |
5555 | return -1; | |
5556 | ||
5557 | return 0; | |
5558 | } | |
5559 | ||
5560 | static int mem_cgroup_oom_notify_cb(struct mem_cgroup *memcg) | |
5561 | { | |
5562 | struct mem_cgroup_eventfd_list *ev; | |
5563 | ||
5564 | list_for_each_entry(ev, &memcg->oom_notify, list) | |
5565 | eventfd_signal(ev->eventfd, 1); | |
5566 | return 0; | |
5567 | } | |
5568 | ||
5569 | static void mem_cgroup_oom_notify(struct mem_cgroup *memcg) | |
5570 | { | |
5571 | struct mem_cgroup *iter; | |
5572 | ||
5573 | for_each_mem_cgroup_tree(iter, memcg) | |
5574 | mem_cgroup_oom_notify_cb(iter); | |
5575 | } | |
5576 | ||
5577 | static int __mem_cgroup_usage_register_event(struct mem_cgroup *memcg, | |
5578 | struct eventfd_ctx *eventfd, const char *args, enum res_type type) | |
5579 | { | |
5580 | struct mem_cgroup_thresholds *thresholds; | |
5581 | struct mem_cgroup_threshold_ary *new; | |
5582 | u64 threshold, usage; | |
5583 | int i, size, ret; | |
5584 | ||
5585 | ret = res_counter_memparse_write_strategy(args, &threshold); | |
5586 | if (ret) | |
5587 | return ret; | |
5588 | ||
5589 | mutex_lock(&memcg->thresholds_lock); | |
5590 | ||
5591 | if (type == _MEM) | |
5592 | thresholds = &memcg->thresholds; | |
5593 | else if (type == _MEMSWAP) | |
5594 | thresholds = &memcg->memsw_thresholds; | |
5595 | else | |
5596 | BUG(); | |
5597 | ||
5598 | usage = mem_cgroup_usage(memcg, type == _MEMSWAP); | |
5599 | ||
5600 | /* Check if a threshold crossed before adding a new one */ | |
5601 | if (thresholds->primary) | |
5602 | __mem_cgroup_threshold(memcg, type == _MEMSWAP); | |
5603 | ||
5604 | size = thresholds->primary ? thresholds->primary->size + 1 : 1; | |
5605 | ||
5606 | /* Allocate memory for new array of thresholds */ | |
5607 | new = kmalloc(sizeof(*new) + size * sizeof(struct mem_cgroup_threshold), | |
5608 | GFP_KERNEL); | |
5609 | if (!new) { | |
5610 | ret = -ENOMEM; | |
5611 | goto unlock; | |
5612 | } | |
5613 | new->size = size; | |
5614 | ||
5615 | /* Copy thresholds (if any) to new array */ | |
5616 | if (thresholds->primary) { | |
5617 | memcpy(new->entries, thresholds->primary->entries, (size - 1) * | |
5618 | sizeof(struct mem_cgroup_threshold)); | |
5619 | } | |
5620 | ||
5621 | /* Add new threshold */ | |
5622 | new->entries[size - 1].eventfd = eventfd; | |
5623 | new->entries[size - 1].threshold = threshold; | |
5624 | ||
5625 | /* Sort thresholds. Registering of new threshold isn't time-critical */ | |
5626 | sort(new->entries, size, sizeof(struct mem_cgroup_threshold), | |
5627 | compare_thresholds, NULL); | |
5628 | ||
5629 | /* Find current threshold */ | |
5630 | new->current_threshold = -1; | |
5631 | for (i = 0; i < size; i++) { | |
5632 | if (new->entries[i].threshold <= usage) { | |
5633 | /* | |
5634 | * new->current_threshold will not be used until | |
5635 | * rcu_assign_pointer(), so it's safe to increment | |
5636 | * it here. | |
5637 | */ | |
5638 | ++new->current_threshold; | |
5639 | } else | |
5640 | break; | |
5641 | } | |
5642 | ||
5643 | /* Free old spare buffer and save old primary buffer as spare */ | |
5644 | kfree(thresholds->spare); | |
5645 | thresholds->spare = thresholds->primary; | |
5646 | ||
5647 | rcu_assign_pointer(thresholds->primary, new); | |
5648 | ||
5649 | /* To be sure that nobody uses thresholds */ | |
5650 | synchronize_rcu(); | |
5651 | ||
5652 | unlock: | |
5653 | mutex_unlock(&memcg->thresholds_lock); | |
5654 | ||
5655 | return ret; | |
5656 | } | |
5657 | ||
5658 | static int mem_cgroup_usage_register_event(struct mem_cgroup *memcg, | |
5659 | struct eventfd_ctx *eventfd, const char *args) | |
5660 | { | |
5661 | return __mem_cgroup_usage_register_event(memcg, eventfd, args, _MEM); | |
5662 | } | |
5663 | ||
5664 | static int memsw_cgroup_usage_register_event(struct mem_cgroup *memcg, | |
5665 | struct eventfd_ctx *eventfd, const char *args) | |
5666 | { | |
5667 | return __mem_cgroup_usage_register_event(memcg, eventfd, args, _MEMSWAP); | |
5668 | } | |
5669 | ||
5670 | static void __mem_cgroup_usage_unregister_event(struct mem_cgroup *memcg, | |
5671 | struct eventfd_ctx *eventfd, enum res_type type) | |
5672 | { | |
5673 | struct mem_cgroup_thresholds *thresholds; | |
5674 | struct mem_cgroup_threshold_ary *new; | |
5675 | u64 usage; | |
5676 | int i, j, size; | |
5677 | ||
5678 | mutex_lock(&memcg->thresholds_lock); | |
5679 | if (type == _MEM) | |
5680 | thresholds = &memcg->thresholds; | |
5681 | else if (type == _MEMSWAP) | |
5682 | thresholds = &memcg->memsw_thresholds; | |
5683 | else | |
5684 | BUG(); | |
5685 | ||
5686 | if (!thresholds->primary) | |
5687 | goto unlock; | |
5688 | ||
5689 | usage = mem_cgroup_usage(memcg, type == _MEMSWAP); | |
5690 | ||
5691 | /* Check if a threshold crossed before removing */ | |
5692 | __mem_cgroup_threshold(memcg, type == _MEMSWAP); | |
5693 | ||
5694 | /* Calculate new number of threshold */ | |
5695 | size = 0; | |
5696 | for (i = 0; i < thresholds->primary->size; i++) { | |
5697 | if (thresholds->primary->entries[i].eventfd != eventfd) | |
5698 | size++; | |
5699 | } | |
5700 | ||
5701 | new = thresholds->spare; | |
5702 | ||
5703 | /* Set thresholds array to NULL if we don't have thresholds */ | |
5704 | if (!size) { | |
5705 | kfree(new); | |
5706 | new = NULL; | |
5707 | goto swap_buffers; | |
5708 | } | |
5709 | ||
5710 | new->size = size; | |
5711 | ||
5712 | /* Copy thresholds and find current threshold */ | |
5713 | new->current_threshold = -1; | |
5714 | for (i = 0, j = 0; i < thresholds->primary->size; i++) { | |
5715 | if (thresholds->primary->entries[i].eventfd == eventfd) | |
5716 | continue; | |
5717 | ||
5718 | new->entries[j] = thresholds->primary->entries[i]; | |
5719 | if (new->entries[j].threshold <= usage) { | |
5720 | /* | |
5721 | * new->current_threshold will not be used | |
5722 | * until rcu_assign_pointer(), so it's safe to increment | |
5723 | * it here. | |
5724 | */ | |
5725 | ++new->current_threshold; | |
5726 | } | |
5727 | j++; | |
5728 | } | |
5729 | ||
5730 | swap_buffers: | |
5731 | /* Swap primary and spare array */ | |
5732 | thresholds->spare = thresholds->primary; | |
5733 | /* If all events are unregistered, free the spare array */ | |
5734 | if (!new) { | |
5735 | kfree(thresholds->spare); | |
5736 | thresholds->spare = NULL; | |
5737 | } | |
5738 | ||
5739 | rcu_assign_pointer(thresholds->primary, new); | |
5740 | ||
5741 | /* To be sure that nobody uses thresholds */ | |
5742 | synchronize_rcu(); | |
5743 | unlock: | |
5744 | mutex_unlock(&memcg->thresholds_lock); | |
5745 | } | |
5746 | ||
5747 | static void mem_cgroup_usage_unregister_event(struct mem_cgroup *memcg, | |
5748 | struct eventfd_ctx *eventfd) | |
5749 | { | |
5750 | return __mem_cgroup_usage_unregister_event(memcg, eventfd, _MEM); | |
5751 | } | |
5752 | ||
5753 | static void memsw_cgroup_usage_unregister_event(struct mem_cgroup *memcg, | |
5754 | struct eventfd_ctx *eventfd) | |
5755 | { | |
5756 | return __mem_cgroup_usage_unregister_event(memcg, eventfd, _MEMSWAP); | |
5757 | } | |
5758 | ||
5759 | static int mem_cgroup_oom_register_event(struct mem_cgroup *memcg, | |
5760 | struct eventfd_ctx *eventfd, const char *args) | |
5761 | { | |
5762 | struct mem_cgroup_eventfd_list *event; | |
5763 | ||
5764 | event = kmalloc(sizeof(*event), GFP_KERNEL); | |
5765 | if (!event) | |
5766 | return -ENOMEM; | |
5767 | ||
5768 | spin_lock(&memcg_oom_lock); | |
5769 | ||
5770 | event->eventfd = eventfd; | |
5771 | list_add(&event->list, &memcg->oom_notify); | |
5772 | ||
5773 | /* already in OOM ? */ | |
5774 | if (atomic_read(&memcg->under_oom)) | |
5775 | eventfd_signal(eventfd, 1); | |
5776 | spin_unlock(&memcg_oom_lock); | |
5777 | ||
5778 | return 0; | |
5779 | } | |
5780 | ||
5781 | static void mem_cgroup_oom_unregister_event(struct mem_cgroup *memcg, | |
5782 | struct eventfd_ctx *eventfd) | |
5783 | { | |
5784 | struct mem_cgroup_eventfd_list *ev, *tmp; | |
5785 | ||
5786 | spin_lock(&memcg_oom_lock); | |
5787 | ||
5788 | list_for_each_entry_safe(ev, tmp, &memcg->oom_notify, list) { | |
5789 | if (ev->eventfd == eventfd) { | |
5790 | list_del(&ev->list); | |
5791 | kfree(ev); | |
5792 | } | |
5793 | } | |
5794 | ||
5795 | spin_unlock(&memcg_oom_lock); | |
5796 | } | |
5797 | ||
5798 | static int mem_cgroup_oom_control_read(struct seq_file *sf, void *v) | |
5799 | { | |
5800 | struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(sf)); | |
5801 | ||
5802 | seq_printf(sf, "oom_kill_disable %d\n", memcg->oom_kill_disable); | |
5803 | seq_printf(sf, "under_oom %d\n", (bool)atomic_read(&memcg->under_oom)); | |
5804 | return 0; | |
5805 | } | |
5806 | ||
5807 | static int mem_cgroup_oom_control_write(struct cgroup_subsys_state *css, | |
5808 | struct cftype *cft, u64 val) | |
5809 | { | |
5810 | struct mem_cgroup *memcg = mem_cgroup_from_css(css); | |
5811 | struct mem_cgroup *parent = mem_cgroup_from_css(css_parent(&memcg->css)); | |
5812 | ||
5813 | /* cannot set to root cgroup and only 0 and 1 are allowed */ | |
5814 | if (!parent || !((val == 0) || (val == 1))) | |
5815 | return -EINVAL; | |
5816 | ||
5817 | mutex_lock(&memcg_create_mutex); | |
5818 | /* oom-kill-disable is a flag for subhierarchy. */ | |
5819 | if ((parent->use_hierarchy) || memcg_has_children(memcg)) { | |
5820 | mutex_unlock(&memcg_create_mutex); | |
5821 | return -EINVAL; | |
5822 | } | |
5823 | memcg->oom_kill_disable = val; | |
5824 | if (!val) | |
5825 | memcg_oom_recover(memcg); | |
5826 | mutex_unlock(&memcg_create_mutex); | |
5827 | return 0; | |
5828 | } | |
5829 | ||
5830 | #ifdef CONFIG_MEMCG_KMEM | |
5831 | static int memcg_init_kmem(struct mem_cgroup *memcg, struct cgroup_subsys *ss) | |
5832 | { | |
5833 | int ret; | |
5834 | ||
5835 | memcg->kmemcg_id = -1; | |
5836 | ret = memcg_propagate_kmem(memcg); | |
5837 | if (ret) | |
5838 | return ret; | |
5839 | ||
5840 | return mem_cgroup_sockets_init(memcg, ss); | |
5841 | } | |
5842 | ||
5843 | static void memcg_destroy_kmem(struct mem_cgroup *memcg) | |
5844 | { | |
5845 | mem_cgroup_sockets_destroy(memcg); | |
5846 | } | |
5847 | ||
5848 | static void kmem_cgroup_css_offline(struct mem_cgroup *memcg) | |
5849 | { | |
5850 | if (!memcg_kmem_is_active(memcg)) | |
5851 | return; | |
5852 | ||
5853 | /* | |
5854 | * kmem charges can outlive the cgroup. In the case of slab | |
5855 | * pages, for instance, a page contain objects from various | |
5856 | * processes. As we prevent from taking a reference for every | |
5857 | * such allocation we have to be careful when doing uncharge | |
5858 | * (see memcg_uncharge_kmem) and here during offlining. | |
5859 | * | |
5860 | * The idea is that that only the _last_ uncharge which sees | |
5861 | * the dead memcg will drop the last reference. An additional | |
5862 | * reference is taken here before the group is marked dead | |
5863 | * which is then paired with css_put during uncharge resp. here. | |
5864 | * | |
5865 | * Although this might sound strange as this path is called from | |
5866 | * css_offline() when the referencemight have dropped down to 0 | |
5867 | * and shouldn't be incremented anymore (css_tryget would fail) | |
5868 | * we do not have other options because of the kmem allocations | |
5869 | * lifetime. | |
5870 | */ | |
5871 | css_get(&memcg->css); | |
5872 | ||
5873 | memcg_kmem_mark_dead(memcg); | |
5874 | ||
5875 | if (res_counter_read_u64(&memcg->kmem, RES_USAGE) != 0) | |
5876 | return; | |
5877 | ||
5878 | if (memcg_kmem_test_and_clear_dead(memcg)) | |
5879 | css_put(&memcg->css); | |
5880 | } | |
5881 | #else | |
5882 | static int memcg_init_kmem(struct mem_cgroup *memcg, struct cgroup_subsys *ss) | |
5883 | { | |
5884 | return 0; | |
5885 | } | |
5886 | ||
5887 | static void memcg_destroy_kmem(struct mem_cgroup *memcg) | |
5888 | { | |
5889 | } | |
5890 | ||
5891 | static void kmem_cgroup_css_offline(struct mem_cgroup *memcg) | |
5892 | { | |
5893 | } | |
5894 | #endif | |
5895 | ||
5896 | /* | |
5897 | * DO NOT USE IN NEW FILES. | |
5898 | * | |
5899 | * "cgroup.event_control" implementation. | |
5900 | * | |
5901 | * This is way over-engineered. It tries to support fully configurable | |
5902 | * events for each user. Such level of flexibility is completely | |
5903 | * unnecessary especially in the light of the planned unified hierarchy. | |
5904 | * | |
5905 | * Please deprecate this and replace with something simpler if at all | |
5906 | * possible. | |
5907 | */ | |
5908 | ||
5909 | /* | |
5910 | * Unregister event and free resources. | |
5911 | * | |
5912 | * Gets called from workqueue. | |
5913 | */ | |
5914 | static void memcg_event_remove(struct work_struct *work) | |
5915 | { | |
5916 | struct mem_cgroup_event *event = | |
5917 | container_of(work, struct mem_cgroup_event, remove); | |
5918 | struct mem_cgroup *memcg = event->memcg; | |
5919 | ||
5920 | remove_wait_queue(event->wqh, &event->wait); | |
5921 | ||
5922 | event->unregister_event(memcg, event->eventfd); | |
5923 | ||
5924 | /* Notify userspace the event is going away. */ | |
5925 | eventfd_signal(event->eventfd, 1); | |
5926 | ||
5927 | eventfd_ctx_put(event->eventfd); | |
5928 | kfree(event); | |
5929 | css_put(&memcg->css); | |
5930 | } | |
5931 | ||
5932 | /* | |
5933 | * Gets called on POLLHUP on eventfd when user closes it. | |
5934 | * | |
5935 | * Called with wqh->lock held and interrupts disabled. | |
5936 | */ | |
5937 | static int memcg_event_wake(wait_queue_t *wait, unsigned mode, | |
5938 | int sync, void *key) | |
5939 | { | |
5940 | struct mem_cgroup_event *event = | |
5941 | container_of(wait, struct mem_cgroup_event, wait); | |
5942 | struct mem_cgroup *memcg = event->memcg; | |
5943 | unsigned long flags = (unsigned long)key; | |
5944 | ||
5945 | if (flags & POLLHUP) { | |
5946 | /* | |
5947 | * If the event has been detached at cgroup removal, we | |
5948 | * can simply return knowing the other side will cleanup | |
5949 | * for us. | |
5950 | * | |
5951 | * We can't race against event freeing since the other | |
5952 | * side will require wqh->lock via remove_wait_queue(), | |
5953 | * which we hold. | |
5954 | */ | |
5955 | spin_lock(&memcg->event_list_lock); | |
5956 | if (!list_empty(&event->list)) { | |
5957 | list_del_init(&event->list); | |
5958 | /* | |
5959 | * We are in atomic context, but cgroup_event_remove() | |
5960 | * may sleep, so we have to call it in workqueue. | |
5961 | */ | |
5962 | schedule_work(&event->remove); | |
5963 | } | |
5964 | spin_unlock(&memcg->event_list_lock); | |
5965 | } | |
5966 | ||
5967 | return 0; | |
5968 | } | |
5969 | ||
5970 | static void memcg_event_ptable_queue_proc(struct file *file, | |
5971 | wait_queue_head_t *wqh, poll_table *pt) | |
5972 | { | |
5973 | struct mem_cgroup_event *event = | |
5974 | container_of(pt, struct mem_cgroup_event, pt); | |
5975 | ||
5976 | event->wqh = wqh; | |
5977 | add_wait_queue(wqh, &event->wait); | |
5978 | } | |
5979 | ||
5980 | /* | |
5981 | * DO NOT USE IN NEW FILES. | |
5982 | * | |
5983 | * Parse input and register new cgroup event handler. | |
5984 | * | |
5985 | * Input must be in format '<event_fd> <control_fd> <args>'. | |
5986 | * Interpretation of args is defined by control file implementation. | |
5987 | */ | |
5988 | static int memcg_write_event_control(struct cgroup_subsys_state *css, | |
5989 | struct cftype *cft, char *buffer) | |
5990 | { | |
5991 | struct mem_cgroup *memcg = mem_cgroup_from_css(css); | |
5992 | struct mem_cgroup_event *event; | |
5993 | struct cgroup_subsys_state *cfile_css; | |
5994 | unsigned int efd, cfd; | |
5995 | struct fd efile; | |
5996 | struct fd cfile; | |
5997 | const char *name; | |
5998 | char *endp; | |
5999 | int ret; | |
6000 | ||
6001 | efd = simple_strtoul(buffer, &endp, 10); | |
6002 | if (*endp != ' ') | |
6003 | return -EINVAL; | |
6004 | buffer = endp + 1; | |
6005 | ||
6006 | cfd = simple_strtoul(buffer, &endp, 10); | |
6007 | if ((*endp != ' ') && (*endp != '\0')) | |
6008 | return -EINVAL; | |
6009 | buffer = endp + 1; | |
6010 | ||
6011 | event = kzalloc(sizeof(*event), GFP_KERNEL); | |
6012 | if (!event) | |
6013 | return -ENOMEM; | |
6014 | ||
6015 | event->memcg = memcg; | |
6016 | INIT_LIST_HEAD(&event->list); | |
6017 | init_poll_funcptr(&event->pt, memcg_event_ptable_queue_proc); | |
6018 | init_waitqueue_func_entry(&event->wait, memcg_event_wake); | |
6019 | INIT_WORK(&event->remove, memcg_event_remove); | |
6020 | ||
6021 | efile = fdget(efd); | |
6022 | if (!efile.file) { | |
6023 | ret = -EBADF; | |
6024 | goto out_kfree; | |
6025 | } | |
6026 | ||
6027 | event->eventfd = eventfd_ctx_fileget(efile.file); | |
6028 | if (IS_ERR(event->eventfd)) { | |
6029 | ret = PTR_ERR(event->eventfd); | |
6030 | goto out_put_efile; | |
6031 | } | |
6032 | ||
6033 | cfile = fdget(cfd); | |
6034 | if (!cfile.file) { | |
6035 | ret = -EBADF; | |
6036 | goto out_put_eventfd; | |
6037 | } | |
6038 | ||
6039 | /* the process need read permission on control file */ | |
6040 | /* AV: shouldn't we check that it's been opened for read instead? */ | |
6041 | ret = inode_permission(file_inode(cfile.file), MAY_READ); | |
6042 | if (ret < 0) | |
6043 | goto out_put_cfile; | |
6044 | ||
6045 | /* | |
6046 | * Determine the event callbacks and set them in @event. This used | |
6047 | * to be done via struct cftype but cgroup core no longer knows | |
6048 | * about these events. The following is crude but the whole thing | |
6049 | * is for compatibility anyway. | |
6050 | * | |
6051 | * DO NOT ADD NEW FILES. | |
6052 | */ | |
6053 | name = cfile.file->f_dentry->d_name.name; | |
6054 | ||
6055 | if (!strcmp(name, "memory.usage_in_bytes")) { | |
6056 | event->register_event = mem_cgroup_usage_register_event; | |
6057 | event->unregister_event = mem_cgroup_usage_unregister_event; | |
6058 | } else if (!strcmp(name, "memory.oom_control")) { | |
6059 | event->register_event = mem_cgroup_oom_register_event; | |
6060 | event->unregister_event = mem_cgroup_oom_unregister_event; | |
6061 | } else if (!strcmp(name, "memory.pressure_level")) { | |
6062 | event->register_event = vmpressure_register_event; | |
6063 | event->unregister_event = vmpressure_unregister_event; | |
6064 | } else if (!strcmp(name, "memory.memsw.usage_in_bytes")) { | |
6065 | event->register_event = memsw_cgroup_usage_register_event; | |
6066 | event->unregister_event = memsw_cgroup_usage_unregister_event; | |
6067 | } else { | |
6068 | ret = -EINVAL; | |
6069 | goto out_put_cfile; | |
6070 | } | |
6071 | ||
6072 | /* | |
6073 | * Verify @cfile should belong to @css. Also, remaining events are | |
6074 | * automatically removed on cgroup destruction but the removal is | |
6075 | * asynchronous, so take an extra ref on @css. | |
6076 | */ | |
6077 | cfile_css = css_tryget_from_dir(cfile.file->f_dentry->d_parent, | |
6078 | &memory_cgrp_subsys); | |
6079 | ret = -EINVAL; | |
6080 | if (IS_ERR(cfile_css)) | |
6081 | goto out_put_cfile; | |
6082 | if (cfile_css != css) { | |
6083 | css_put(cfile_css); | |
6084 | goto out_put_cfile; | |
6085 | } | |
6086 | ||
6087 | ret = event->register_event(memcg, event->eventfd, buffer); | |
6088 | if (ret) | |
6089 | goto out_put_css; | |
6090 | ||
6091 | efile.file->f_op->poll(efile.file, &event->pt); | |
6092 | ||
6093 | spin_lock(&memcg->event_list_lock); | |
6094 | list_add(&event->list, &memcg->event_list); | |
6095 | spin_unlock(&memcg->event_list_lock); | |
6096 | ||
6097 | fdput(cfile); | |
6098 | fdput(efile); | |
6099 | ||
6100 | return 0; | |
6101 | ||
6102 | out_put_css: | |
6103 | css_put(css); | |
6104 | out_put_cfile: | |
6105 | fdput(cfile); | |
6106 | out_put_eventfd: | |
6107 | eventfd_ctx_put(event->eventfd); | |
6108 | out_put_efile: | |
6109 | fdput(efile); | |
6110 | out_kfree: | |
6111 | kfree(event); | |
6112 | ||
6113 | return ret; | |
6114 | } | |
6115 | ||
6116 | static struct cftype mem_cgroup_files[] = { | |
6117 | { | |
6118 | .name = "usage_in_bytes", | |
6119 | .private = MEMFILE_PRIVATE(_MEM, RES_USAGE), | |
6120 | .read_u64 = mem_cgroup_read_u64, | |
6121 | }, | |
6122 | { | |
6123 | .name = "max_usage_in_bytes", | |
6124 | .private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE), | |
6125 | .trigger = mem_cgroup_reset, | |
6126 | .read_u64 = mem_cgroup_read_u64, | |
6127 | }, | |
6128 | { | |
6129 | .name = "limit_in_bytes", | |
6130 | .private = MEMFILE_PRIVATE(_MEM, RES_LIMIT), | |
6131 | .write_string = mem_cgroup_write, | |
6132 | .read_u64 = mem_cgroup_read_u64, | |
6133 | }, | |
6134 | { | |
6135 | .name = "soft_limit_in_bytes", | |
6136 | .private = MEMFILE_PRIVATE(_MEM, RES_SOFT_LIMIT), | |
6137 | .write_string = mem_cgroup_write, | |
6138 | .read_u64 = mem_cgroup_read_u64, | |
6139 | }, | |
6140 | { | |
6141 | .name = "failcnt", | |
6142 | .private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT), | |
6143 | .trigger = mem_cgroup_reset, | |
6144 | .read_u64 = mem_cgroup_read_u64, | |
6145 | }, | |
6146 | { | |
6147 | .name = "stat", | |
6148 | .seq_show = memcg_stat_show, | |
6149 | }, | |
6150 | { | |
6151 | .name = "force_empty", | |
6152 | .trigger = mem_cgroup_force_empty_write, | |
6153 | }, | |
6154 | { | |
6155 | .name = "use_hierarchy", | |
6156 | .flags = CFTYPE_INSANE, | |
6157 | .write_u64 = mem_cgroup_hierarchy_write, | |
6158 | .read_u64 = mem_cgroup_hierarchy_read, | |
6159 | }, | |
6160 | { | |
6161 | .name = "cgroup.event_control", /* XXX: for compat */ | |
6162 | .write_string = memcg_write_event_control, | |
6163 | .flags = CFTYPE_NO_PREFIX, | |
6164 | .mode = S_IWUGO, | |
6165 | }, | |
6166 | { | |
6167 | .name = "swappiness", | |
6168 | .read_u64 = mem_cgroup_swappiness_read, | |
6169 | .write_u64 = mem_cgroup_swappiness_write, | |
6170 | }, | |
6171 | { | |
6172 | .name = "move_charge_at_immigrate", | |
6173 | .read_u64 = mem_cgroup_move_charge_read, | |
6174 | .write_u64 = mem_cgroup_move_charge_write, | |
6175 | }, | |
6176 | { | |
6177 | .name = "oom_control", | |
6178 | .seq_show = mem_cgroup_oom_control_read, | |
6179 | .write_u64 = mem_cgroup_oom_control_write, | |
6180 | .private = MEMFILE_PRIVATE(_OOM_TYPE, OOM_CONTROL), | |
6181 | }, | |
6182 | { | |
6183 | .name = "pressure_level", | |
6184 | }, | |
6185 | #ifdef CONFIG_NUMA | |
6186 | { | |
6187 | .name = "numa_stat", | |
6188 | .seq_show = memcg_numa_stat_show, | |
6189 | }, | |
6190 | #endif | |
6191 | #ifdef CONFIG_MEMCG_KMEM | |
6192 | { | |
6193 | .name = "kmem.limit_in_bytes", | |
6194 | .private = MEMFILE_PRIVATE(_KMEM, RES_LIMIT), | |
6195 | .write_string = mem_cgroup_write, | |
6196 | .read_u64 = mem_cgroup_read_u64, | |
6197 | }, | |
6198 | { | |
6199 | .name = "kmem.usage_in_bytes", | |
6200 | .private = MEMFILE_PRIVATE(_KMEM, RES_USAGE), | |
6201 | .read_u64 = mem_cgroup_read_u64, | |
6202 | }, | |
6203 | { | |
6204 | .name = "kmem.failcnt", | |
6205 | .private = MEMFILE_PRIVATE(_KMEM, RES_FAILCNT), | |
6206 | .trigger = mem_cgroup_reset, | |
6207 | .read_u64 = mem_cgroup_read_u64, | |
6208 | }, | |
6209 | { | |
6210 | .name = "kmem.max_usage_in_bytes", | |
6211 | .private = MEMFILE_PRIVATE(_KMEM, RES_MAX_USAGE), | |
6212 | .trigger = mem_cgroup_reset, | |
6213 | .read_u64 = mem_cgroup_read_u64, | |
6214 | }, | |
6215 | #ifdef CONFIG_SLABINFO | |
6216 | { | |
6217 | .name = "kmem.slabinfo", | |
6218 | .seq_show = mem_cgroup_slabinfo_read, | |
6219 | }, | |
6220 | #endif | |
6221 | #endif | |
6222 | { }, /* terminate */ | |
6223 | }; | |
6224 | ||
6225 | #ifdef CONFIG_MEMCG_SWAP | |
6226 | static struct cftype memsw_cgroup_files[] = { | |
6227 | { | |
6228 | .name = "memsw.usage_in_bytes", | |
6229 | .private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE), | |
6230 | .read_u64 = mem_cgroup_read_u64, | |
6231 | }, | |
6232 | { | |
6233 | .name = "memsw.max_usage_in_bytes", | |
6234 | .private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE), | |
6235 | .trigger = mem_cgroup_reset, | |
6236 | .read_u64 = mem_cgroup_read_u64, | |
6237 | }, | |
6238 | { | |
6239 | .name = "memsw.limit_in_bytes", | |
6240 | .private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT), | |
6241 | .write_string = mem_cgroup_write, | |
6242 | .read_u64 = mem_cgroup_read_u64, | |
6243 | }, | |
6244 | { | |
6245 | .name = "memsw.failcnt", | |
6246 | .private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT), | |
6247 | .trigger = mem_cgroup_reset, | |
6248 | .read_u64 = mem_cgroup_read_u64, | |
6249 | }, | |
6250 | { }, /* terminate */ | |
6251 | }; | |
6252 | #endif | |
6253 | static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *memcg, int node) | |
6254 | { | |
6255 | struct mem_cgroup_per_node *pn; | |
6256 | struct mem_cgroup_per_zone *mz; | |
6257 | int zone, tmp = node; | |
6258 | /* | |
6259 | * This routine is called against possible nodes. | |
6260 | * But it's BUG to call kmalloc() against offline node. | |
6261 | * | |
6262 | * TODO: this routine can waste much memory for nodes which will | |
6263 | * never be onlined. It's better to use memory hotplug callback | |
6264 | * function. | |
6265 | */ | |
6266 | if (!node_state(node, N_NORMAL_MEMORY)) | |
6267 | tmp = -1; | |
6268 | pn = kzalloc_node(sizeof(*pn), GFP_KERNEL, tmp); | |
6269 | if (!pn) | |
6270 | return 1; | |
6271 | ||
6272 | for (zone = 0; zone < MAX_NR_ZONES; zone++) { | |
6273 | mz = &pn->zoneinfo[zone]; | |
6274 | lruvec_init(&mz->lruvec); | |
6275 | mz->usage_in_excess = 0; | |
6276 | mz->on_tree = false; | |
6277 | mz->memcg = memcg; | |
6278 | } | |
6279 | memcg->nodeinfo[node] = pn; | |
6280 | return 0; | |
6281 | } | |
6282 | ||
6283 | static void free_mem_cgroup_per_zone_info(struct mem_cgroup *memcg, int node) | |
6284 | { | |
6285 | kfree(memcg->nodeinfo[node]); | |
6286 | } | |
6287 | ||
6288 | static struct mem_cgroup *mem_cgroup_alloc(void) | |
6289 | { | |
6290 | struct mem_cgroup *memcg; | |
6291 | size_t size; | |
6292 | ||
6293 | size = sizeof(struct mem_cgroup); | |
6294 | size += nr_node_ids * sizeof(struct mem_cgroup_per_node *); | |
6295 | ||
6296 | memcg = kzalloc(size, GFP_KERNEL); | |
6297 | if (!memcg) | |
6298 | return NULL; | |
6299 | ||
6300 | memcg->stat = alloc_percpu(struct mem_cgroup_stat_cpu); | |
6301 | if (!memcg->stat) | |
6302 | goto out_free; | |
6303 | spin_lock_init(&memcg->pcp_counter_lock); | |
6304 | return memcg; | |
6305 | ||
6306 | out_free: | |
6307 | kfree(memcg); | |
6308 | return NULL; | |
6309 | } | |
6310 | ||
6311 | /* | |
6312 | * At destroying mem_cgroup, references from swap_cgroup can remain. | |
6313 | * (scanning all at force_empty is too costly...) | |
6314 | * | |
6315 | * Instead of clearing all references at force_empty, we remember | |
6316 | * the number of reference from swap_cgroup and free mem_cgroup when | |
6317 | * it goes down to 0. | |
6318 | * | |
6319 | * Removal of cgroup itself succeeds regardless of refs from swap. | |
6320 | */ | |
6321 | ||
6322 | static void __mem_cgroup_free(struct mem_cgroup *memcg) | |
6323 | { | |
6324 | int node; | |
6325 | ||
6326 | mem_cgroup_remove_from_trees(memcg); | |
6327 | ||
6328 | for_each_node(node) | |
6329 | free_mem_cgroup_per_zone_info(memcg, node); | |
6330 | ||
6331 | free_percpu(memcg->stat); | |
6332 | ||
6333 | /* | |
6334 | * We need to make sure that (at least for now), the jump label | |
6335 | * destruction code runs outside of the cgroup lock. This is because | |
6336 | * get_online_cpus(), which is called from the static_branch update, | |
6337 | * can't be called inside the cgroup_lock. cpusets are the ones | |
6338 | * enforcing this dependency, so if they ever change, we might as well. | |
6339 | * | |
6340 | * schedule_work() will guarantee this happens. Be careful if you need | |
6341 | * to move this code around, and make sure it is outside | |
6342 | * the cgroup_lock. | |
6343 | */ | |
6344 | disarm_static_keys(memcg); | |
6345 | kfree(memcg); | |
6346 | } | |
6347 | ||
6348 | /* | |
6349 | * Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled. | |
6350 | */ | |
6351 | struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *memcg) | |
6352 | { | |
6353 | if (!memcg->res.parent) | |
6354 | return NULL; | |
6355 | return mem_cgroup_from_res_counter(memcg->res.parent, res); | |
6356 | } | |
6357 | EXPORT_SYMBOL(parent_mem_cgroup); | |
6358 | ||
6359 | static void __init mem_cgroup_soft_limit_tree_init(void) | |
6360 | { | |
6361 | struct mem_cgroup_tree_per_node *rtpn; | |
6362 | struct mem_cgroup_tree_per_zone *rtpz; | |
6363 | int tmp, node, zone; | |
6364 | ||
6365 | for_each_node(node) { | |
6366 | tmp = node; | |
6367 | if (!node_state(node, N_NORMAL_MEMORY)) | |
6368 | tmp = -1; | |
6369 | rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL, tmp); | |
6370 | BUG_ON(!rtpn); | |
6371 | ||
6372 | soft_limit_tree.rb_tree_per_node[node] = rtpn; | |
6373 | ||
6374 | for (zone = 0; zone < MAX_NR_ZONES; zone++) { | |
6375 | rtpz = &rtpn->rb_tree_per_zone[zone]; | |
6376 | rtpz->rb_root = RB_ROOT; | |
6377 | spin_lock_init(&rtpz->lock); | |
6378 | } | |
6379 | } | |
6380 | } | |
6381 | ||
6382 | static struct cgroup_subsys_state * __ref | |
6383 | mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) | |
6384 | { | |
6385 | struct mem_cgroup *memcg; | |
6386 | long error = -ENOMEM; | |
6387 | int node; | |
6388 | ||
6389 | memcg = mem_cgroup_alloc(); | |
6390 | if (!memcg) | |
6391 | return ERR_PTR(error); | |
6392 | ||
6393 | for_each_node(node) | |
6394 | if (alloc_mem_cgroup_per_zone_info(memcg, node)) | |
6395 | goto free_out; | |
6396 | ||
6397 | /* root ? */ | |
6398 | if (parent_css == NULL) { | |
6399 | root_mem_cgroup = memcg; | |
6400 | res_counter_init(&memcg->res, NULL); | |
6401 | res_counter_init(&memcg->memsw, NULL); | |
6402 | res_counter_init(&memcg->kmem, NULL); | |
6403 | } | |
6404 | ||
6405 | memcg->last_scanned_node = MAX_NUMNODES; | |
6406 | INIT_LIST_HEAD(&memcg->oom_notify); | |
6407 | memcg->move_charge_at_immigrate = 0; | |
6408 | mutex_init(&memcg->thresholds_lock); | |
6409 | spin_lock_init(&memcg->move_lock); | |
6410 | vmpressure_init(&memcg->vmpressure); | |
6411 | INIT_LIST_HEAD(&memcg->event_list); | |
6412 | spin_lock_init(&memcg->event_list_lock); | |
6413 | ||
6414 | return &memcg->css; | |
6415 | ||
6416 | free_out: | |
6417 | __mem_cgroup_free(memcg); | |
6418 | return ERR_PTR(error); | |
6419 | } | |
6420 | ||
6421 | static int | |
6422 | mem_cgroup_css_online(struct cgroup_subsys_state *css) | |
6423 | { | |
6424 | struct mem_cgroup *memcg = mem_cgroup_from_css(css); | |
6425 | struct mem_cgroup *parent = mem_cgroup_from_css(css_parent(css)); | |
6426 | ||
6427 | if (css->cgroup->id > MEM_CGROUP_ID_MAX) | |
6428 | return -ENOSPC; | |
6429 | ||
6430 | if (!parent) | |
6431 | return 0; | |
6432 | ||
6433 | mutex_lock(&memcg_create_mutex); | |
6434 | ||
6435 | memcg->use_hierarchy = parent->use_hierarchy; | |
6436 | memcg->oom_kill_disable = parent->oom_kill_disable; | |
6437 | memcg->swappiness = mem_cgroup_swappiness(parent); | |
6438 | ||
6439 | if (parent->use_hierarchy) { | |
6440 | res_counter_init(&memcg->res, &parent->res); | |
6441 | res_counter_init(&memcg->memsw, &parent->memsw); | |
6442 | res_counter_init(&memcg->kmem, &parent->kmem); | |
6443 | ||
6444 | /* | |
6445 | * No need to take a reference to the parent because cgroup | |
6446 | * core guarantees its existence. | |
6447 | */ | |
6448 | } else { | |
6449 | res_counter_init(&memcg->res, NULL); | |
6450 | res_counter_init(&memcg->memsw, NULL); | |
6451 | res_counter_init(&memcg->kmem, NULL); | |
6452 | /* | |
6453 | * Deeper hierachy with use_hierarchy == false doesn't make | |
6454 | * much sense so let cgroup subsystem know about this | |
6455 | * unfortunate state in our controller. | |
6456 | */ | |
6457 | if (parent != root_mem_cgroup) | |
6458 | memory_cgrp_subsys.broken_hierarchy = true; | |
6459 | } | |
6460 | mutex_unlock(&memcg_create_mutex); | |
6461 | ||
6462 | return memcg_init_kmem(memcg, &memory_cgrp_subsys); | |
6463 | } | |
6464 | ||
6465 | /* | |
6466 | * Announce all parents that a group from their hierarchy is gone. | |
6467 | */ | |
6468 | static void mem_cgroup_invalidate_reclaim_iterators(struct mem_cgroup *memcg) | |
6469 | { | |
6470 | struct mem_cgroup *parent = memcg; | |
6471 | ||
6472 | while ((parent = parent_mem_cgroup(parent))) | |
6473 | mem_cgroup_iter_invalidate(parent); | |
6474 | ||
6475 | /* | |
6476 | * if the root memcg is not hierarchical we have to check it | |
6477 | * explicitely. | |
6478 | */ | |
6479 | if (!root_mem_cgroup->use_hierarchy) | |
6480 | mem_cgroup_iter_invalidate(root_mem_cgroup); | |
6481 | } | |
6482 | ||
6483 | static void mem_cgroup_css_offline(struct cgroup_subsys_state *css) | |
6484 | { | |
6485 | struct mem_cgroup *memcg = mem_cgroup_from_css(css); | |
6486 | struct mem_cgroup_event *event, *tmp; | |
6487 | struct cgroup_subsys_state *iter; | |
6488 | ||
6489 | /* | |
6490 | * Unregister events and notify userspace. | |
6491 | * Notify userspace about cgroup removing only after rmdir of cgroup | |
6492 | * directory to avoid race between userspace and kernelspace. | |
6493 | */ | |
6494 | spin_lock(&memcg->event_list_lock); | |
6495 | list_for_each_entry_safe(event, tmp, &memcg->event_list, list) { | |
6496 | list_del_init(&event->list); | |
6497 | schedule_work(&event->remove); | |
6498 | } | |
6499 | spin_unlock(&memcg->event_list_lock); | |
6500 | ||
6501 | kmem_cgroup_css_offline(memcg); | |
6502 | ||
6503 | mem_cgroup_invalidate_reclaim_iterators(memcg); | |
6504 | ||
6505 | /* | |
6506 | * This requires that offlining is serialized. Right now that is | |
6507 | * guaranteed because css_killed_work_fn() holds the cgroup_mutex. | |
6508 | */ | |
6509 | css_for_each_descendant_post(iter, css) | |
6510 | mem_cgroup_reparent_charges(mem_cgroup_from_css(iter)); | |
6511 | ||
6512 | mem_cgroup_destroy_all_caches(memcg); | |
6513 | vmpressure_cleanup(&memcg->vmpressure); | |
6514 | } | |
6515 | ||
6516 | static void mem_cgroup_css_free(struct cgroup_subsys_state *css) | |
6517 | { | |
6518 | struct mem_cgroup *memcg = mem_cgroup_from_css(css); | |
6519 | /* | |
6520 | * XXX: css_offline() would be where we should reparent all | |
6521 | * memory to prepare the cgroup for destruction. However, | |
6522 | * memcg does not do css_tryget() and res_counter charging | |
6523 | * under the same RCU lock region, which means that charging | |
6524 | * could race with offlining. Offlining only happens to | |
6525 | * cgroups with no tasks in them but charges can show up | |
6526 | * without any tasks from the swapin path when the target | |
6527 | * memcg is looked up from the swapout record and not from the | |
6528 | * current task as it usually is. A race like this can leak | |
6529 | * charges and put pages with stale cgroup pointers into | |
6530 | * circulation: | |
6531 | * | |
6532 | * #0 #1 | |
6533 | * lookup_swap_cgroup_id() | |
6534 | * rcu_read_lock() | |
6535 | * mem_cgroup_lookup() | |
6536 | * css_tryget() | |
6537 | * rcu_read_unlock() | |
6538 | * disable css_tryget() | |
6539 | * call_rcu() | |
6540 | * offline_css() | |
6541 | * reparent_charges() | |
6542 | * res_counter_charge() | |
6543 | * css_put() | |
6544 | * css_free() | |
6545 | * pc->mem_cgroup = dead memcg | |
6546 | * add page to lru | |
6547 | * | |
6548 | * The bulk of the charges are still moved in offline_css() to | |
6549 | * avoid pinning a lot of pages in case a long-term reference | |
6550 | * like a swapout record is deferring the css_free() to long | |
6551 | * after offlining. But this makes sure we catch any charges | |
6552 | * made after offlining: | |
6553 | */ | |
6554 | mem_cgroup_reparent_charges(memcg); | |
6555 | ||
6556 | memcg_destroy_kmem(memcg); | |
6557 | __mem_cgroup_free(memcg); | |
6558 | } | |
6559 | ||
6560 | #ifdef CONFIG_MMU | |
6561 | /* Handlers for move charge at task migration. */ | |
6562 | #define PRECHARGE_COUNT_AT_ONCE 256 | |
6563 | static int mem_cgroup_do_precharge(unsigned long count) | |
6564 | { | |
6565 | int ret = 0; | |
6566 | int batch_count = PRECHARGE_COUNT_AT_ONCE; | |
6567 | struct mem_cgroup *memcg = mc.to; | |
6568 | ||
6569 | if (mem_cgroup_is_root(memcg)) { | |
6570 | mc.precharge += count; | |
6571 | /* we don't need css_get for root */ | |
6572 | return ret; | |
6573 | } | |
6574 | /* try to charge at once */ | |
6575 | if (count > 1) { | |
6576 | struct res_counter *dummy; | |
6577 | /* | |
6578 | * "memcg" cannot be under rmdir() because we've already checked | |
6579 | * by cgroup_lock_live_cgroup() that it is not removed and we | |
6580 | * are still under the same cgroup_mutex. So we can postpone | |
6581 | * css_get(). | |
6582 | */ | |
6583 | if (res_counter_charge(&memcg->res, PAGE_SIZE * count, &dummy)) | |
6584 | goto one_by_one; | |
6585 | if (do_swap_account && res_counter_charge(&memcg->memsw, | |
6586 | PAGE_SIZE * count, &dummy)) { | |
6587 | res_counter_uncharge(&memcg->res, PAGE_SIZE * count); | |
6588 | goto one_by_one; | |
6589 | } | |
6590 | mc.precharge += count; | |
6591 | return ret; | |
6592 | } | |
6593 | one_by_one: | |
6594 | /* fall back to one by one charge */ | |
6595 | while (count--) { | |
6596 | if (signal_pending(current)) { | |
6597 | ret = -EINTR; | |
6598 | break; | |
6599 | } | |
6600 | if (!batch_count--) { | |
6601 | batch_count = PRECHARGE_COUNT_AT_ONCE; | |
6602 | cond_resched(); | |
6603 | } | |
6604 | ret = __mem_cgroup_try_charge(NULL, | |
6605 | GFP_KERNEL, 1, &memcg, false); | |
6606 | if (ret) | |
6607 | /* mem_cgroup_clear_mc() will do uncharge later */ | |
6608 | return ret; | |
6609 | mc.precharge++; | |
6610 | } | |
6611 | return ret; | |
6612 | } | |
6613 | ||
6614 | /** | |
6615 | * get_mctgt_type - get target type of moving charge | |
6616 | * @vma: the vma the pte to be checked belongs | |
6617 | * @addr: the address corresponding to the pte to be checked | |
6618 | * @ptent: the pte to be checked | |
6619 | * @target: the pointer the target page or swap ent will be stored(can be NULL) | |
6620 | * | |
6621 | * Returns | |
6622 | * 0(MC_TARGET_NONE): if the pte is not a target for move charge. | |
6623 | * 1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for | |
6624 | * move charge. if @target is not NULL, the page is stored in target->page | |
6625 | * with extra refcnt got(Callers should handle it). | |
6626 | * 2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a | |
6627 | * target for charge migration. if @target is not NULL, the entry is stored | |
6628 | * in target->ent. | |
6629 | * | |
6630 | * Called with pte lock held. | |
6631 | */ | |
6632 | union mc_target { | |
6633 | struct page *page; | |
6634 | swp_entry_t ent; | |
6635 | }; | |
6636 | ||
6637 | enum mc_target_type { | |
6638 | MC_TARGET_NONE = 0, | |
6639 | MC_TARGET_PAGE, | |
6640 | MC_TARGET_SWAP, | |
6641 | }; | |
6642 | ||
6643 | static struct page *mc_handle_present_pte(struct vm_area_struct *vma, | |
6644 | unsigned long addr, pte_t ptent) | |
6645 | { | |
6646 | struct page *page = vm_normal_page(vma, addr, ptent); | |
6647 | ||
6648 | if (!page || !page_mapped(page)) | |
6649 | return NULL; | |
6650 | if (PageAnon(page)) { | |
6651 | /* we don't move shared anon */ | |
6652 | if (!move_anon()) | |
6653 | return NULL; | |
6654 | } else if (!move_file()) | |
6655 | /* we ignore mapcount for file pages */ | |
6656 | return NULL; | |
6657 | if (!get_page_unless_zero(page)) | |
6658 | return NULL; | |
6659 | ||
6660 | return page; | |
6661 | } | |
6662 | ||
6663 | #ifdef CONFIG_SWAP | |
6664 | static struct page *mc_handle_swap_pte(struct vm_area_struct *vma, | |
6665 | unsigned long addr, pte_t ptent, swp_entry_t *entry) | |
6666 | { | |
6667 | struct page *page = NULL; | |
6668 | swp_entry_t ent = pte_to_swp_entry(ptent); | |
6669 | ||
6670 | if (!move_anon() || non_swap_entry(ent)) | |
6671 | return NULL; | |
6672 | /* | |
6673 | * Because lookup_swap_cache() updates some statistics counter, | |
6674 | * we call find_get_page() with swapper_space directly. | |
6675 | */ | |
6676 | page = find_get_page(swap_address_space(ent), ent.val); | |
6677 | if (do_swap_account) | |
6678 | entry->val = ent.val; | |
6679 | ||
6680 | return page; | |
6681 | } | |
6682 | #else | |
6683 | static struct page *mc_handle_swap_pte(struct vm_area_struct *vma, | |
6684 | unsigned long addr, pte_t ptent, swp_entry_t *entry) | |
6685 | { | |
6686 | return NULL; | |
6687 | } | |
6688 | #endif | |
6689 | ||
6690 | static struct page *mc_handle_file_pte(struct vm_area_struct *vma, | |
6691 | unsigned long addr, pte_t ptent, swp_entry_t *entry) | |
6692 | { | |
6693 | struct page *page = NULL; | |
6694 | struct address_space *mapping; | |
6695 | pgoff_t pgoff; | |
6696 | ||
6697 | if (!vma->vm_file) /* anonymous vma */ | |
6698 | return NULL; | |
6699 | if (!move_file()) | |
6700 | return NULL; | |
6701 | ||
6702 | mapping = vma->vm_file->f_mapping; | |
6703 | if (pte_none(ptent)) | |
6704 | pgoff = linear_page_index(vma, addr); | |
6705 | else /* pte_file(ptent) is true */ | |
6706 | pgoff = pte_to_pgoff(ptent); | |
6707 | ||
6708 | /* page is moved even if it's not RSS of this task(page-faulted). */ | |
6709 | page = find_get_page(mapping, pgoff); | |
6710 | ||
6711 | #ifdef CONFIG_SWAP | |
6712 | /* shmem/tmpfs may report page out on swap: account for that too. */ | |
6713 | if (radix_tree_exceptional_entry(page)) { | |
6714 | swp_entry_t swap = radix_to_swp_entry(page); | |
6715 | if (do_swap_account) | |
6716 | *entry = swap; | |
6717 | page = find_get_page(swap_address_space(swap), swap.val); | |
6718 | } | |
6719 | #endif | |
6720 | return page; | |
6721 | } | |
6722 | ||
6723 | static enum mc_target_type get_mctgt_type(struct vm_area_struct *vma, | |
6724 | unsigned long addr, pte_t ptent, union mc_target *target) | |
6725 | { | |
6726 | struct page *page = NULL; | |
6727 | struct page_cgroup *pc; | |
6728 | enum mc_target_type ret = MC_TARGET_NONE; | |
6729 | swp_entry_t ent = { .val = 0 }; | |
6730 | ||
6731 | if (pte_present(ptent)) | |
6732 | page = mc_handle_present_pte(vma, addr, ptent); | |
6733 | else if (is_swap_pte(ptent)) | |
6734 | page = mc_handle_swap_pte(vma, addr, ptent, &ent); | |
6735 | else if (pte_none(ptent) || pte_file(ptent)) | |
6736 | page = mc_handle_file_pte(vma, addr, ptent, &ent); | |
6737 | ||
6738 | if (!page && !ent.val) | |
6739 | return ret; | |
6740 | if (page) { | |
6741 | pc = lookup_page_cgroup(page); | |
6742 | /* | |
6743 | * Do only loose check w/o page_cgroup lock. | |
6744 | * mem_cgroup_move_account() checks the pc is valid or not under | |
6745 | * the lock. | |
6746 | */ | |
6747 | if (PageCgroupUsed(pc) && pc->mem_cgroup == mc.from) { | |
6748 | ret = MC_TARGET_PAGE; | |
6749 | if (target) | |
6750 | target->page = page; | |
6751 | } | |
6752 | if (!ret || !target) | |
6753 | put_page(page); | |
6754 | } | |
6755 | /* There is a swap entry and a page doesn't exist or isn't charged */ | |
6756 | if (ent.val && !ret && | |
6757 | mem_cgroup_id(mc.from) == lookup_swap_cgroup_id(ent)) { | |
6758 | ret = MC_TARGET_SWAP; | |
6759 | if (target) | |
6760 | target->ent = ent; | |
6761 | } | |
6762 | return ret; | |
6763 | } | |
6764 | ||
6765 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE | |
6766 | /* | |
6767 | * We don't consider swapping or file mapped pages because THP does not | |
6768 | * support them for now. | |
6769 | * Caller should make sure that pmd_trans_huge(pmd) is true. | |
6770 | */ | |
6771 | static enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma, | |
6772 | unsigned long addr, pmd_t pmd, union mc_target *target) | |
6773 | { | |
6774 | struct page *page = NULL; | |
6775 | struct page_cgroup *pc; | |
6776 | enum mc_target_type ret = MC_TARGET_NONE; | |
6777 | ||
6778 | page = pmd_page(pmd); | |
6779 | VM_BUG_ON_PAGE(!page || !PageHead(page), page); | |
6780 | if (!move_anon()) | |
6781 | return ret; | |
6782 | pc = lookup_page_cgroup(page); | |
6783 | if (PageCgroupUsed(pc) && pc->mem_cgroup == mc.from) { | |
6784 | ret = MC_TARGET_PAGE; | |
6785 | if (target) { | |
6786 | get_page(page); | |
6787 | target->page = page; | |
6788 | } | |
6789 | } | |
6790 | return ret; | |
6791 | } | |
6792 | #else | |
6793 | static inline enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma, | |
6794 | unsigned long addr, pmd_t pmd, union mc_target *target) | |
6795 | { | |
6796 | return MC_TARGET_NONE; | |
6797 | } | |
6798 | #endif | |
6799 | ||
6800 | static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd, | |
6801 | unsigned long addr, unsigned long end, | |
6802 | struct mm_walk *walk) | |
6803 | { | |
6804 | struct vm_area_struct *vma = walk->private; | |
6805 | pte_t *pte; | |
6806 | spinlock_t *ptl; | |
6807 | ||
6808 | if (pmd_trans_huge_lock(pmd, vma, &ptl) == 1) { | |
6809 | if (get_mctgt_type_thp(vma, addr, *pmd, NULL) == MC_TARGET_PAGE) | |
6810 | mc.precharge += HPAGE_PMD_NR; | |
6811 | spin_unlock(ptl); | |
6812 | return 0; | |
6813 | } | |
6814 | ||
6815 | if (pmd_trans_unstable(pmd)) | |
6816 | return 0; | |
6817 | pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); | |
6818 | for (; addr != end; pte++, addr += PAGE_SIZE) | |
6819 | if (get_mctgt_type(vma, addr, *pte, NULL)) | |
6820 | mc.precharge++; /* increment precharge temporarily */ | |
6821 | pte_unmap_unlock(pte - 1, ptl); | |
6822 | cond_resched(); | |
6823 | ||
6824 | return 0; | |
6825 | } | |
6826 | ||
6827 | static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm) | |
6828 | { | |
6829 | unsigned long precharge; | |
6830 | struct vm_area_struct *vma; | |
6831 | ||
6832 | down_read(&mm->mmap_sem); | |
6833 | for (vma = mm->mmap; vma; vma = vma->vm_next) { | |
6834 | struct mm_walk mem_cgroup_count_precharge_walk = { | |
6835 | .pmd_entry = mem_cgroup_count_precharge_pte_range, | |
6836 | .mm = mm, | |
6837 | .private = vma, | |
6838 | }; | |
6839 | if (is_vm_hugetlb_page(vma)) | |
6840 | continue; | |
6841 | walk_page_range(vma->vm_start, vma->vm_end, | |
6842 | &mem_cgroup_count_precharge_walk); | |
6843 | } | |
6844 | up_read(&mm->mmap_sem); | |
6845 | ||
6846 | precharge = mc.precharge; | |
6847 | mc.precharge = 0; | |
6848 | ||
6849 | return precharge; | |
6850 | } | |
6851 | ||
6852 | static int mem_cgroup_precharge_mc(struct mm_struct *mm) | |
6853 | { | |
6854 | unsigned long precharge = mem_cgroup_count_precharge(mm); | |
6855 | ||
6856 | VM_BUG_ON(mc.moving_task); | |
6857 | mc.moving_task = current; | |
6858 | return mem_cgroup_do_precharge(precharge); | |
6859 | } | |
6860 | ||
6861 | /* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */ | |
6862 | static void __mem_cgroup_clear_mc(void) | |
6863 | { | |
6864 | struct mem_cgroup *from = mc.from; | |
6865 | struct mem_cgroup *to = mc.to; | |
6866 | int i; | |
6867 | ||
6868 | /* we must uncharge all the leftover precharges from mc.to */ | |
6869 | if (mc.precharge) { | |
6870 | __mem_cgroup_cancel_charge(mc.to, mc.precharge); | |
6871 | mc.precharge = 0; | |
6872 | } | |
6873 | /* | |
6874 | * we didn't uncharge from mc.from at mem_cgroup_move_account(), so | |
6875 | * we must uncharge here. | |
6876 | */ | |
6877 | if (mc.moved_charge) { | |
6878 | __mem_cgroup_cancel_charge(mc.from, mc.moved_charge); | |
6879 | mc.moved_charge = 0; | |
6880 | } | |
6881 | /* we must fixup refcnts and charges */ | |
6882 | if (mc.moved_swap) { | |
6883 | /* uncharge swap account from the old cgroup */ | |
6884 | if (!mem_cgroup_is_root(mc.from)) | |
6885 | res_counter_uncharge(&mc.from->memsw, | |
6886 | PAGE_SIZE * mc.moved_swap); | |
6887 | ||
6888 | for (i = 0; i < mc.moved_swap; i++) | |
6889 | css_put(&mc.from->css); | |
6890 | ||
6891 | if (!mem_cgroup_is_root(mc.to)) { | |
6892 | /* | |
6893 | * we charged both to->res and to->memsw, so we should | |
6894 | * uncharge to->res. | |
6895 | */ | |
6896 | res_counter_uncharge(&mc.to->res, | |
6897 | PAGE_SIZE * mc.moved_swap); | |
6898 | } | |
6899 | /* we've already done css_get(mc.to) */ | |
6900 | mc.moved_swap = 0; | |
6901 | } | |
6902 | memcg_oom_recover(from); | |
6903 | memcg_oom_recover(to); | |
6904 | wake_up_all(&mc.waitq); | |
6905 | } | |
6906 | ||
6907 | static void mem_cgroup_clear_mc(void) | |
6908 | { | |
6909 | struct mem_cgroup *from = mc.from; | |
6910 | ||
6911 | /* | |
6912 | * we must clear moving_task before waking up waiters at the end of | |
6913 | * task migration. | |
6914 | */ | |
6915 | mc.moving_task = NULL; | |
6916 | __mem_cgroup_clear_mc(); | |
6917 | spin_lock(&mc.lock); | |
6918 | mc.from = NULL; | |
6919 | mc.to = NULL; | |
6920 | spin_unlock(&mc.lock); | |
6921 | mem_cgroup_end_move(from); | |
6922 | } | |
6923 | ||
6924 | static int mem_cgroup_can_attach(struct cgroup_subsys_state *css, | |
6925 | struct cgroup_taskset *tset) | |
6926 | { | |
6927 | struct task_struct *p = cgroup_taskset_first(tset); | |
6928 | int ret = 0; | |
6929 | struct mem_cgroup *memcg = mem_cgroup_from_css(css); | |
6930 | unsigned long move_charge_at_immigrate; | |
6931 | ||
6932 | /* | |
6933 | * We are now commited to this value whatever it is. Changes in this | |
6934 | * tunable will only affect upcoming migrations, not the current one. | |
6935 | * So we need to save it, and keep it going. | |
6936 | */ | |
6937 | move_charge_at_immigrate = memcg->move_charge_at_immigrate; | |
6938 | if (move_charge_at_immigrate) { | |
6939 | struct mm_struct *mm; | |
6940 | struct mem_cgroup *from = mem_cgroup_from_task(p); | |
6941 | ||
6942 | VM_BUG_ON(from == memcg); | |
6943 | ||
6944 | mm = get_task_mm(p); | |
6945 | if (!mm) | |
6946 | return 0; | |
6947 | /* We move charges only when we move a owner of the mm */ | |
6948 | if (mm->owner == p) { | |
6949 | VM_BUG_ON(mc.from); | |
6950 | VM_BUG_ON(mc.to); | |
6951 | VM_BUG_ON(mc.precharge); | |
6952 | VM_BUG_ON(mc.moved_charge); | |
6953 | VM_BUG_ON(mc.moved_swap); | |
6954 | mem_cgroup_start_move(from); | |
6955 | spin_lock(&mc.lock); | |
6956 | mc.from = from; | |
6957 | mc.to = memcg; | |
6958 | mc.immigrate_flags = move_charge_at_immigrate; | |
6959 | spin_unlock(&mc.lock); | |
6960 | /* We set mc.moving_task later */ | |
6961 | ||
6962 | ret = mem_cgroup_precharge_mc(mm); | |
6963 | if (ret) | |
6964 | mem_cgroup_clear_mc(); | |
6965 | } | |
6966 | mmput(mm); | |
6967 | } | |
6968 | return ret; | |
6969 | } | |
6970 | ||
6971 | static void mem_cgroup_cancel_attach(struct cgroup_subsys_state *css, | |
6972 | struct cgroup_taskset *tset) | |
6973 | { | |
6974 | mem_cgroup_clear_mc(); | |
6975 | } | |
6976 | ||
6977 | static int mem_cgroup_move_charge_pte_range(pmd_t *pmd, | |
6978 | unsigned long addr, unsigned long end, | |
6979 | struct mm_walk *walk) | |
6980 | { | |
6981 | int ret = 0; | |
6982 | struct vm_area_struct *vma = walk->private; | |
6983 | pte_t *pte; | |
6984 | spinlock_t *ptl; | |
6985 | enum mc_target_type target_type; | |
6986 | union mc_target target; | |
6987 | struct page *page; | |
6988 | struct page_cgroup *pc; | |
6989 | ||
6990 | /* | |
6991 | * We don't take compound_lock() here but no race with splitting thp | |
6992 | * happens because: | |
6993 | * - if pmd_trans_huge_lock() returns 1, the relevant thp is not | |
6994 | * under splitting, which means there's no concurrent thp split, | |
6995 | * - if another thread runs into split_huge_page() just after we | |
6996 | * entered this if-block, the thread must wait for page table lock | |
6997 | * to be unlocked in __split_huge_page_splitting(), where the main | |
6998 | * part of thp split is not executed yet. | |
6999 | */ | |
7000 | if (pmd_trans_huge_lock(pmd, vma, &ptl) == 1) { | |
7001 | if (mc.precharge < HPAGE_PMD_NR) { | |
7002 | spin_unlock(ptl); | |
7003 | return 0; | |
7004 | } | |
7005 | target_type = get_mctgt_type_thp(vma, addr, *pmd, &target); | |
7006 | if (target_type == MC_TARGET_PAGE) { | |
7007 | page = target.page; | |
7008 | if (!isolate_lru_page(page)) { | |
7009 | pc = lookup_page_cgroup(page); | |
7010 | if (!mem_cgroup_move_account(page, HPAGE_PMD_NR, | |
7011 | pc, mc.from, mc.to)) { | |
7012 | mc.precharge -= HPAGE_PMD_NR; | |
7013 | mc.moved_charge += HPAGE_PMD_NR; | |
7014 | } | |
7015 | putback_lru_page(page); | |
7016 | } | |
7017 | put_page(page); | |
7018 | } | |
7019 | spin_unlock(ptl); | |
7020 | return 0; | |
7021 | } | |
7022 | ||
7023 | if (pmd_trans_unstable(pmd)) | |
7024 | return 0; | |
7025 | retry: | |
7026 | pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); | |
7027 | for (; addr != end; addr += PAGE_SIZE) { | |
7028 | pte_t ptent = *(pte++); | |
7029 | swp_entry_t ent; | |
7030 | ||
7031 | if (!mc.precharge) | |
7032 | break; | |
7033 | ||
7034 | switch (get_mctgt_type(vma, addr, ptent, &target)) { | |
7035 | case MC_TARGET_PAGE: | |
7036 | page = target.page; | |
7037 | if (isolate_lru_page(page)) | |
7038 | goto put; | |
7039 | pc = lookup_page_cgroup(page); | |
7040 | if (!mem_cgroup_move_account(page, 1, pc, | |
7041 | mc.from, mc.to)) { | |
7042 | mc.precharge--; | |
7043 | /* we uncharge from mc.from later. */ | |
7044 | mc.moved_charge++; | |
7045 | } | |
7046 | putback_lru_page(page); | |
7047 | put: /* get_mctgt_type() gets the page */ | |
7048 | put_page(page); | |
7049 | break; | |
7050 | case MC_TARGET_SWAP: | |
7051 | ent = target.ent; | |
7052 | if (!mem_cgroup_move_swap_account(ent, mc.from, mc.to)) { | |
7053 | mc.precharge--; | |
7054 | /* we fixup refcnts and charges later. */ | |
7055 | mc.moved_swap++; | |
7056 | } | |
7057 | break; | |
7058 | default: | |
7059 | break; | |
7060 | } | |
7061 | } | |
7062 | pte_unmap_unlock(pte - 1, ptl); | |
7063 | cond_resched(); | |
7064 | ||
7065 | if (addr != end) { | |
7066 | /* | |
7067 | * We have consumed all precharges we got in can_attach(). | |
7068 | * We try charge one by one, but don't do any additional | |
7069 | * charges to mc.to if we have failed in charge once in attach() | |
7070 | * phase. | |
7071 | */ | |
7072 | ret = mem_cgroup_do_precharge(1); | |
7073 | if (!ret) | |
7074 | goto retry; | |
7075 | } | |
7076 | ||
7077 | return ret; | |
7078 | } | |
7079 | ||
7080 | static void mem_cgroup_move_charge(struct mm_struct *mm) | |
7081 | { | |
7082 | struct vm_area_struct *vma; | |
7083 | ||
7084 | lru_add_drain_all(); | |
7085 | retry: | |
7086 | if (unlikely(!down_read_trylock(&mm->mmap_sem))) { | |
7087 | /* | |
7088 | * Someone who are holding the mmap_sem might be waiting in | |
7089 | * waitq. So we cancel all extra charges, wake up all waiters, | |
7090 | * and retry. Because we cancel precharges, we might not be able | |
7091 | * to move enough charges, but moving charge is a best-effort | |
7092 | * feature anyway, so it wouldn't be a big problem. | |
7093 | */ | |
7094 | __mem_cgroup_clear_mc(); | |
7095 | cond_resched(); | |
7096 | goto retry; | |
7097 | } | |
7098 | for (vma = mm->mmap; vma; vma = vma->vm_next) { | |
7099 | int ret; | |
7100 | struct mm_walk mem_cgroup_move_charge_walk = { | |
7101 | .pmd_entry = mem_cgroup_move_charge_pte_range, | |
7102 | .mm = mm, | |
7103 | .private = vma, | |
7104 | }; | |
7105 | if (is_vm_hugetlb_page(vma)) | |
7106 | continue; | |
7107 | ret = walk_page_range(vma->vm_start, vma->vm_end, | |
7108 | &mem_cgroup_move_charge_walk); | |
7109 | if (ret) | |
7110 | /* | |
7111 | * means we have consumed all precharges and failed in | |
7112 | * doing additional charge. Just abandon here. | |
7113 | */ | |
7114 | break; | |
7115 | } | |
7116 | up_read(&mm->mmap_sem); | |
7117 | } | |
7118 | ||
7119 | static void mem_cgroup_move_task(struct cgroup_subsys_state *css, | |
7120 | struct cgroup_taskset *tset) | |
7121 | { | |
7122 | struct task_struct *p = cgroup_taskset_first(tset); | |
7123 | struct mm_struct *mm = get_task_mm(p); | |
7124 | ||
7125 | if (mm) { | |
7126 | if (mc.to) | |
7127 | mem_cgroup_move_charge(mm); | |
7128 | mmput(mm); | |
7129 | } | |
7130 | if (mc.to) | |
7131 | mem_cgroup_clear_mc(); | |
7132 | } | |
7133 | #else /* !CONFIG_MMU */ | |
7134 | static int mem_cgroup_can_attach(struct cgroup_subsys_state *css, | |
7135 | struct cgroup_taskset *tset) | |
7136 | { | |
7137 | return 0; | |
7138 | } | |
7139 | static void mem_cgroup_cancel_attach(struct cgroup_subsys_state *css, | |
7140 | struct cgroup_taskset *tset) | |
7141 | { | |
7142 | } | |
7143 | static void mem_cgroup_move_task(struct cgroup_subsys_state *css, | |
7144 | struct cgroup_taskset *tset) | |
7145 | { | |
7146 | } | |
7147 | #endif | |
7148 | ||
7149 | /* | |
7150 | * Cgroup retains root cgroups across [un]mount cycles making it necessary | |
7151 | * to verify sane_behavior flag on each mount attempt. | |
7152 | */ | |
7153 | static void mem_cgroup_bind(struct cgroup_subsys_state *root_css) | |
7154 | { | |
7155 | /* | |
7156 | * use_hierarchy is forced with sane_behavior. cgroup core | |
7157 | * guarantees that @root doesn't have any children, so turning it | |
7158 | * on for the root memcg is enough. | |
7159 | */ | |
7160 | if (cgroup_sane_behavior(root_css->cgroup)) | |
7161 | mem_cgroup_from_css(root_css)->use_hierarchy = true; | |
7162 | } | |
7163 | ||
7164 | struct cgroup_subsys memory_cgrp_subsys = { | |
7165 | .css_alloc = mem_cgroup_css_alloc, | |
7166 | .css_online = mem_cgroup_css_online, | |
7167 | .css_offline = mem_cgroup_css_offline, | |
7168 | .css_free = mem_cgroup_css_free, | |
7169 | .can_attach = mem_cgroup_can_attach, | |
7170 | .cancel_attach = mem_cgroup_cancel_attach, | |
7171 | .attach = mem_cgroup_move_task, | |
7172 | .bind = mem_cgroup_bind, | |
7173 | .base_cftypes = mem_cgroup_files, | |
7174 | .early_init = 0, | |
7175 | }; | |
7176 | ||
7177 | #ifdef CONFIG_MEMCG_SWAP | |
7178 | static int __init enable_swap_account(char *s) | |
7179 | { | |
7180 | if (!strcmp(s, "1")) | |
7181 | really_do_swap_account = 1; | |
7182 | else if (!strcmp(s, "0")) | |
7183 | really_do_swap_account = 0; | |
7184 | return 1; | |
7185 | } | |
7186 | __setup("swapaccount=", enable_swap_account); | |
7187 | ||
7188 | static void __init memsw_file_init(void) | |
7189 | { | |
7190 | WARN_ON(cgroup_add_cftypes(&memory_cgrp_subsys, memsw_cgroup_files)); | |
7191 | } | |
7192 | ||
7193 | static void __init enable_swap_cgroup(void) | |
7194 | { | |
7195 | if (!mem_cgroup_disabled() && really_do_swap_account) { | |
7196 | do_swap_account = 1; | |
7197 | memsw_file_init(); | |
7198 | } | |
7199 | } | |
7200 | ||
7201 | #else | |
7202 | static void __init enable_swap_cgroup(void) | |
7203 | { | |
7204 | } | |
7205 | #endif | |
7206 | ||
7207 | /* | |
7208 | * subsys_initcall() for memory controller. | |
7209 | * | |
7210 | * Some parts like hotcpu_notifier() have to be initialized from this context | |
7211 | * because of lock dependencies (cgroup_lock -> cpu hotplug) but basically | |
7212 | * everything that doesn't depend on a specific mem_cgroup structure should | |
7213 | * be initialized from here. | |
7214 | */ | |
7215 | static int __init mem_cgroup_init(void) | |
7216 | { | |
7217 | hotcpu_notifier(memcg_cpu_hotplug_callback, 0); | |
7218 | enable_swap_cgroup(); | |
7219 | mem_cgroup_soft_limit_tree_init(); | |
7220 | memcg_stock_init(); | |
7221 | return 0; | |
7222 | } | |
7223 | subsys_initcall(mem_cgroup_init); |