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