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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/poll.h> |
49 | #include <linux/sort.h> |
50 | #include <linux/fs.h> |
51 | #include <linux/seq_file.h> |
52 | #include <linux/vmpressure.h> |
53 | #include <linux/mm_inline.h> |
54 | #include <linux/page_cgroup.h> |
55 | #include <linux/cpu.h> |
56 | #include <linux/oom.h> |
57 | #include <linux/lockdep.h> |
58 | #include <linux/file.h> |
59 | #include "internal.h" |
60 | #include <net/sock.h> |
61 | #include <net/ip.h> |
62 | #include <net/tcp_memcontrol.h> |
63 | #include "slab.h" |
64 | |
65 | #include <asm/uaccess.h> |
66 | |
67 | #include <trace/events/vmscan.h> |
68 | |
69 | struct cgroup_subsys memory_cgrp_subsys __read_mostly; |
70 | EXPORT_SYMBOL(memory_cgrp_subsys); |
71 | |
72 | #define MEM_CGROUP_RECLAIM_RETRIES 5 |
73 | static struct mem_cgroup *root_mem_cgroup __read_mostly; |
74 | |
75 | #ifdef CONFIG_MEMCG_SWAP |
76 | /* Turned on only when memory cgroup is enabled && really_do_swap_account = 1 */ |
77 | int do_swap_account __read_mostly; |
78 | |
79 | /* for remember boot option*/ |
80 | #ifdef CONFIG_MEMCG_SWAP_ENABLED |
81 | static int really_do_swap_account __initdata = 1; |
82 | #else |
83 | static int really_do_swap_account __initdata = 0; |
84 | #endif |
85 | |
86 | #else |
87 | #define do_swap_account 0 |
88 | #endif |
89 | |
90 | |
91 | static const char * const mem_cgroup_stat_names[] = { |
92 | "cache", |
93 | "rss", |
94 | "rss_huge", |
95 | "mapped_file", |
96 | "writeback", |
97 | "swap", |
98 | }; |
99 | |
100 | enum mem_cgroup_events_index { |
101 | MEM_CGROUP_EVENTS_PGPGIN, /* # of pages paged in */ |
102 | MEM_CGROUP_EVENTS_PGPGOUT, /* # of pages paged out */ |
103 | MEM_CGROUP_EVENTS_PGFAULT, /* # of page-faults */ |
104 | MEM_CGROUP_EVENTS_PGMAJFAULT, /* # of major page-faults */ |
105 | MEM_CGROUP_EVENTS_NSTATS, |
106 | }; |
107 | |
108 | static const char * const mem_cgroup_events_names[] = { |
109 | "pgpgin", |
110 | "pgpgout", |
111 | "pgfault", |
112 | "pgmajfault", |
113 | }; |
114 | |
115 | static const char * const mem_cgroup_lru_names[] = { |
116 | "inactive_anon", |
117 | "active_anon", |
118 | "inactive_file", |
119 | "active_file", |
120 | "unevictable", |
121 | }; |
122 | |
123 | /* |
124 | * Per memcg event counter is incremented at every pagein/pageout. With THP, |
125 | * it will be incremated by the number of pages. This counter is used for |
126 | * for trigger some periodic events. This is straightforward and better |
127 | * than using jiffies etc. to handle periodic memcg event. |
128 | */ |
129 | enum mem_cgroup_events_target { |
130 | MEM_CGROUP_TARGET_THRESH, |
131 | MEM_CGROUP_TARGET_SOFTLIMIT, |
132 | MEM_CGROUP_TARGET_NUMAINFO, |
133 | MEM_CGROUP_NTARGETS, |
134 | }; |
135 | #define THRESHOLDS_EVENTS_TARGET 128 |
136 | #define SOFTLIMIT_EVENTS_TARGET 1024 |
137 | #define NUMAINFO_EVENTS_TARGET 1024 |
138 | |
139 | struct mem_cgroup_stat_cpu { |
140 | long count[MEM_CGROUP_STAT_NSTATS]; |
141 | unsigned long events[MEM_CGROUP_EVENTS_NSTATS]; |
142 | unsigned long nr_page_events; |
143 | unsigned long targets[MEM_CGROUP_NTARGETS]; |
144 | }; |
145 | |
146 | struct mem_cgroup_reclaim_iter { |
147 | /* |
148 | * last scanned hierarchy member. Valid only if last_dead_count |
149 | * matches memcg->dead_count of the hierarchy root group. |
150 | */ |
151 | struct mem_cgroup *last_visited; |
152 | int last_dead_count; |
153 | |
154 | /* scan generation, increased every round-trip */ |
155 | unsigned int generation; |
156 | }; |
157 | |
158 | /* |
159 | * per-zone information in memory controller. |
160 | */ |
161 | struct mem_cgroup_per_zone { |
162 | struct lruvec lruvec; |
163 | unsigned long lru_size[NR_LRU_LISTS]; |
164 | |
165 | struct mem_cgroup_reclaim_iter reclaim_iter[DEF_PRIORITY + 1]; |
166 | |
167 | struct rb_node tree_node; /* RB tree node */ |
168 | unsigned long long usage_in_excess;/* Set to the value by which */ |
169 | /* the soft limit is exceeded*/ |
170 | bool on_tree; |
171 | struct mem_cgroup *memcg; /* Back pointer, we cannot */ |
172 | /* use container_of */ |
173 | }; |
174 | |
175 | struct mem_cgroup_per_node { |
176 | struct mem_cgroup_per_zone zoneinfo[MAX_NR_ZONES]; |
177 | }; |
178 | |
179 | /* |
180 | * Cgroups above their limits are maintained in a RB-Tree, independent of |
181 | * their hierarchy representation |
182 | */ |
183 | |
184 | struct mem_cgroup_tree_per_zone { |
185 | struct rb_root rb_root; |
186 | spinlock_t lock; |
187 | }; |
188 | |
189 | struct mem_cgroup_tree_per_node { |
190 | struct mem_cgroup_tree_per_zone rb_tree_per_zone[MAX_NR_ZONES]; |
191 | }; |
192 | |
193 | struct mem_cgroup_tree { |
194 | struct mem_cgroup_tree_per_node *rb_tree_per_node[MAX_NUMNODES]; |
195 | }; |
196 | |
197 | static struct mem_cgroup_tree soft_limit_tree __read_mostly; |
198 | |
199 | struct mem_cgroup_threshold { |
200 | struct eventfd_ctx *eventfd; |
201 | u64 threshold; |
202 | }; |
203 | |
204 | /* For threshold */ |
205 | struct mem_cgroup_threshold_ary { |
206 | /* An array index points to threshold just below or equal to usage. */ |
207 | int current_threshold; |
208 | /* Size of entries[] */ |
209 | unsigned int size; |
210 | /* Array of thresholds */ |
211 | struct mem_cgroup_threshold entries[0]; |
212 | }; |
213 | |
214 | struct mem_cgroup_thresholds { |
215 | /* Primary thresholds array */ |
216 | struct mem_cgroup_threshold_ary *primary; |
217 | /* |
218 | * Spare threshold array. |
219 | * This is needed to make mem_cgroup_unregister_event() "never fail". |
220 | * It must be able to store at least primary->size - 1 entries. |
221 | */ |
222 | struct mem_cgroup_threshold_ary *spare; |
223 | }; |
224 | |
225 | /* for OOM */ |
226 | struct mem_cgroup_eventfd_list { |
227 | struct list_head list; |
228 | struct eventfd_ctx *eventfd; |
229 | }; |
230 | |
231 | /* |
232 | * cgroup_event represents events which userspace want to receive. |
233 | */ |
234 | struct mem_cgroup_event { |
235 | /* |
236 | * memcg which the event belongs to. |
237 | */ |
238 | struct mem_cgroup *memcg; |
239 | /* |
240 | * eventfd to signal userspace about the event. |
241 | */ |
242 | struct eventfd_ctx *eventfd; |
243 | /* |
244 | * Each of these stored in a list by the cgroup. |
245 | */ |
246 | struct list_head list; |
247 | /* |
248 | * register_event() callback will be used to add new userspace |
249 | * waiter for changes related to this event. Use eventfd_signal() |
250 | * on eventfd to send notification to userspace. |
251 | */ |
252 | int (*register_event)(struct mem_cgroup *memcg, |
253 | struct eventfd_ctx *eventfd, const char *args); |
254 | /* |
255 | * unregister_event() callback will be called when userspace closes |
256 | * the eventfd or on cgroup removing. This callback must be set, |
257 | * if you want provide notification functionality. |
258 | */ |
259 | void (*unregister_event)(struct mem_cgroup *memcg, |
260 | struct eventfd_ctx *eventfd); |
261 | /* |
262 | * All fields below needed to unregister event when |
263 | * userspace closes eventfd. |
264 | */ |
265 | poll_table pt; |
266 | wait_queue_head_t *wqh; |
267 | wait_queue_t wait; |
268 | struct work_struct remove; |
269 | }; |
270 | |
271 | static void mem_cgroup_threshold(struct mem_cgroup *memcg); |
272 | static void mem_cgroup_oom_notify(struct mem_cgroup *memcg); |
273 | |
274 | /* |
275 | * The memory controller data structure. The memory controller controls both |
276 | * page cache and RSS per cgroup. We would eventually like to provide |
277 | * statistics based on the statistics developed by Rik Van Riel for clock-pro, |
278 | * to help the administrator determine what knobs to tune. |
279 | * |
280 | * TODO: Add a water mark for the memory controller. Reclaim will begin when |
281 | * we hit the water mark. May be even add a low water mark, such that |
282 | * no reclaim occurs from a cgroup at it's low water mark, this is |
283 | * a feature that will be implemented much later in the future. |
284 | */ |
285 | struct mem_cgroup { |
286 | struct cgroup_subsys_state css; |
287 | /* |
288 | * the counter to account for memory usage |
289 | */ |
290 | struct res_counter res; |
291 | |
292 | /* vmpressure notifications */ |
293 | struct vmpressure vmpressure; |
294 | |
295 | /* |
296 | * the counter to account for mem+swap usage. |
297 | */ |
298 | struct res_counter memsw; |
299 | |
300 | /* |
301 | * the counter to account for kernel memory usage. |
302 | */ |
303 | struct res_counter kmem; |
304 | /* |
305 | * Should the accounting and control be hierarchical, per subtree? |
306 | */ |
307 | bool use_hierarchy; |
308 | unsigned long kmem_account_flags; /* See KMEM_ACCOUNTED_*, below */ |
309 | |
310 | bool oom_lock; |
311 | atomic_t under_oom; |
312 | atomic_t oom_wakeups; |
313 | |
314 | int swappiness; |
315 | /* OOM-Killer disable */ |
316 | int oom_kill_disable; |
317 | |
318 | /* set when res.limit == memsw.limit */ |
319 | bool memsw_is_minimum; |
320 | |
321 | /* protect arrays of thresholds */ |
322 | struct mutex thresholds_lock; |
323 | |
324 | /* thresholds for memory usage. RCU-protected */ |
325 | struct mem_cgroup_thresholds thresholds; |
326 | |
327 | /* thresholds for mem+swap usage. RCU-protected */ |
328 | struct mem_cgroup_thresholds memsw_thresholds; |
329 | |
330 | /* For oom notifier event fd */ |
331 | struct list_head oom_notify; |
332 | |
333 | /* |
334 | * Should we move charges of a task when a task is moved into this |
335 | * mem_cgroup ? And what type of charges should we move ? |
336 | */ |
337 | unsigned long move_charge_at_immigrate; |
338 | /* |
339 | * set > 0 if pages under this cgroup are moving to other cgroup. |
340 | */ |
341 | atomic_t moving_account; |
342 | /* taken only while moving_account > 0 */ |
343 | spinlock_t move_lock; |
344 | /* |
345 | * percpu counter. |
346 | */ |
347 | struct mem_cgroup_stat_cpu __percpu *stat; |
348 | /* |
349 | * used when a cpu is offlined or other synchronizations |
350 | * See mem_cgroup_read_stat(). |
351 | */ |
352 | struct mem_cgroup_stat_cpu nocpu_base; |
353 | spinlock_t pcp_counter_lock; |
354 | |
355 | atomic_t dead_count; |
356 | #if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_INET) |
357 | struct cg_proto tcp_mem; |
358 | #endif |
359 | #if defined(CONFIG_MEMCG_KMEM) |
360 | /* analogous to slab_common's slab_caches list. per-memcg */ |
361 | struct list_head memcg_slab_caches; |
362 | /* Not a spinlock, we can take a lot of time walking the list */ |
363 | struct mutex slab_caches_mutex; |
364 | /* Index in the kmem_cache->memcg_params->memcg_caches array */ |
365 | int kmemcg_id; |
366 | #endif |
367 | |
368 | int last_scanned_node; |
369 | #if MAX_NUMNODES > 1 |
370 | nodemask_t scan_nodes; |
371 | atomic_t numainfo_events; |
372 | atomic_t numainfo_updating; |
373 | #endif |
374 | |
375 | /* List of events which userspace want to receive */ |
376 | struct list_head event_list; |
377 | spinlock_t event_list_lock; |
378 | |
379 | struct mem_cgroup_per_node *nodeinfo[0]; |
380 | /* WARNING: nodeinfo must be the last member here */ |
381 | }; |
382 | |
383 | /* internal only representation about the status of kmem accounting. */ |
384 | enum { |
385 | KMEM_ACCOUNTED_ACTIVE, /* accounted by this cgroup itself */ |
386 | KMEM_ACCOUNTED_DEAD, /* dead memcg with pending kmem charges */ |
387 | }; |
388 | |
389 | #ifdef CONFIG_MEMCG_KMEM |
390 | static inline void memcg_kmem_set_active(struct mem_cgroup *memcg) |
391 | { |
392 | set_bit(KMEM_ACCOUNTED_ACTIVE, &memcg->kmem_account_flags); |
393 | } |
394 | |
395 | static bool memcg_kmem_is_active(struct mem_cgroup *memcg) |
396 | { |
397 | return test_bit(KMEM_ACCOUNTED_ACTIVE, &memcg->kmem_account_flags); |
398 | } |
399 | |
400 | static void memcg_kmem_mark_dead(struct mem_cgroup *memcg) |
401 | { |
402 | /* |
403 | * Our caller must use css_get() first, because memcg_uncharge_kmem() |
404 | * will call css_put() if it sees the memcg is dead. |
405 | */ |
406 | smp_wmb(); |
407 | if (test_bit(KMEM_ACCOUNTED_ACTIVE, &memcg->kmem_account_flags)) |
408 | set_bit(KMEM_ACCOUNTED_DEAD, &memcg->kmem_account_flags); |
409 | } |
410 | |
411 | static bool memcg_kmem_test_and_clear_dead(struct mem_cgroup *memcg) |
412 | { |
413 | return test_and_clear_bit(KMEM_ACCOUNTED_DEAD, |
414 | &memcg->kmem_account_flags); |
415 | } |
416 | #endif |
417 | |
418 | /* Stuffs for move charges at task migration. */ |
419 | /* |
420 | * Types of charges to be moved. "move_charge_at_immitgrate" and |
421 | * "immigrate_flags" are treated as a left-shifted bitmap of these types. |
422 | */ |
423 | enum move_type { |
424 | MOVE_CHARGE_TYPE_ANON, /* private anonymous page and swap of it */ |
425 | MOVE_CHARGE_TYPE_FILE, /* file page(including tmpfs) and swap of it */ |
426 | NR_MOVE_TYPE, |
427 | }; |
428 | |
429 | /* "mc" and its members are protected by cgroup_mutex */ |
430 | static struct move_charge_struct { |
431 | spinlock_t lock; /* for from, to */ |
432 | struct mem_cgroup *from; |
433 | struct mem_cgroup *to; |
434 | unsigned long immigrate_flags; |
435 | unsigned long precharge; |
436 | unsigned long moved_charge; |
437 | unsigned long moved_swap; |
438 | struct task_struct *moving_task; /* a task moving charges */ |
439 | wait_queue_head_t waitq; /* a waitq for other context */ |
440 | } mc = { |
441 | .lock = __SPIN_LOCK_UNLOCKED(mc.lock), |
442 | .waitq = __WAIT_QUEUE_HEAD_INITIALIZER(mc.waitq), |
443 | }; |
444 | |
445 | static bool move_anon(void) |
446 | { |
447 | return test_bit(MOVE_CHARGE_TYPE_ANON, &mc.immigrate_flags); |
448 | } |
449 | |
450 | static bool move_file(void) |
451 | { |
452 | return test_bit(MOVE_CHARGE_TYPE_FILE, &mc.immigrate_flags); |
453 | } |
454 | |
455 | /* |
456 | * Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft |
457 | * limit reclaim to prevent infinite loops, if they ever occur. |
458 | */ |
459 | #define MEM_CGROUP_MAX_RECLAIM_LOOPS 100 |
460 | #define MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS 2 |
461 | |
462 | enum charge_type { |
463 | MEM_CGROUP_CHARGE_TYPE_CACHE = 0, |
464 | MEM_CGROUP_CHARGE_TYPE_ANON, |
465 | MEM_CGROUP_CHARGE_TYPE_SWAPOUT, /* for accounting swapcache */ |
466 | MEM_CGROUP_CHARGE_TYPE_DROP, /* a page was unused swap cache */ |
467 | NR_CHARGE_TYPE, |
468 | }; |
469 | |
470 | /* for encoding cft->private value on file */ |
471 | enum res_type { |
472 | _MEM, |
473 | _MEMSWAP, |
474 | _OOM_TYPE, |
475 | _KMEM, |
476 | }; |
477 | |
478 | #define MEMFILE_PRIVATE(x, val) ((x) << 16 | (val)) |
479 | #define MEMFILE_TYPE(val) ((val) >> 16 & 0xffff) |
480 | #define MEMFILE_ATTR(val) ((val) & 0xffff) |
481 | /* Used for OOM nofiier */ |
482 | #define OOM_CONTROL (0) |
483 | |
484 | /* |
485 | * Reclaim flags for mem_cgroup_hierarchical_reclaim |
486 | */ |
487 | #define MEM_CGROUP_RECLAIM_NOSWAP_BIT 0x0 |
488 | #define MEM_CGROUP_RECLAIM_NOSWAP (1 << MEM_CGROUP_RECLAIM_NOSWAP_BIT) |
489 | #define MEM_CGROUP_RECLAIM_SHRINK_BIT 0x1 |
490 | #define MEM_CGROUP_RECLAIM_SHRINK (1 << MEM_CGROUP_RECLAIM_SHRINK_BIT) |
491 | |
492 | /* |
493 | * The memcg_create_mutex will be held whenever a new cgroup is created. |
494 | * As a consequence, any change that needs to protect against new child cgroups |
495 | * appearing has to hold it as well. |
496 | */ |
497 | static DEFINE_MUTEX(memcg_create_mutex); |
498 | |
499 | struct mem_cgroup *mem_cgroup_from_css(struct cgroup_subsys_state *s) |
500 | { |
501 | return s ? container_of(s, struct mem_cgroup, css) : NULL; |
502 | } |
503 | |
504 | /* Some nice accessors for the vmpressure. */ |
505 | struct vmpressure *memcg_to_vmpressure(struct mem_cgroup *memcg) |
506 | { |
507 | if (!memcg) |
508 | memcg = root_mem_cgroup; |
509 | return &memcg->vmpressure; |
510 | } |
511 | |
512 | struct cgroup_subsys_state *vmpressure_to_css(struct vmpressure *vmpr) |
513 | { |
514 | return &container_of(vmpr, struct mem_cgroup, vmpressure)->css; |
515 | } |
516 | |
517 | static inline bool mem_cgroup_is_root(struct mem_cgroup *memcg) |
518 | { |
519 | return (memcg == root_mem_cgroup); |
520 | } |
521 | |
522 | /* |
523 | * We restrict the id in the range of [1, 65535], so it can fit into |
524 | * an unsigned short. |
525 | */ |
526 | #define MEM_CGROUP_ID_MAX USHRT_MAX |
527 | |
528 | static inline unsigned short mem_cgroup_id(struct mem_cgroup *memcg) |
529 | { |
530 | /* |
531 | * The ID of the root cgroup is 0, but memcg treat 0 as an |
532 | * invalid ID, so we return (cgroup_id + 1). |
533 | */ |
534 | return memcg->css.cgroup->id + 1; |
535 | } |
536 | |
537 | static inline struct mem_cgroup *mem_cgroup_from_id(unsigned short id) |
538 | { |
539 | struct cgroup_subsys_state *css; |
540 | |
541 | css = css_from_id(id - 1, &memory_cgrp_subsys); |
542 | return mem_cgroup_from_css(css); |
543 | } |
544 | |
545 | /* Writing them here to avoid exposing memcg's inner layout */ |
546 | #if defined(CONFIG_INET) && defined(CONFIG_MEMCG_KMEM) |
547 | |
548 | void sock_update_memcg(struct sock *sk) |
549 | { |
550 | if (mem_cgroup_sockets_enabled) { |
551 | struct mem_cgroup *memcg; |
552 | struct cg_proto *cg_proto; |
553 | |
554 | BUG_ON(!sk->sk_prot->proto_cgroup); |
555 | |
556 | /* Socket cloning can throw us here with sk_cgrp already |
557 | * filled. It won't however, necessarily happen from |
558 | * process context. So the test for root memcg given |
559 | * the current task's memcg won't help us in this case. |
560 | * |
561 | * Respecting the original socket's memcg is a better |
562 | * decision in this case. |
563 | */ |
564 | if (sk->sk_cgrp) { |
565 | BUG_ON(mem_cgroup_is_root(sk->sk_cgrp->memcg)); |
566 | css_get(&sk->sk_cgrp->memcg->css); |
567 | return; |
568 | } |
569 | |
570 | rcu_read_lock(); |
571 | memcg = mem_cgroup_from_task(current); |
572 | cg_proto = sk->sk_prot->proto_cgroup(memcg); |
573 | if (!mem_cgroup_is_root(memcg) && |
574 | memcg_proto_active(cg_proto) && css_tryget(&memcg->css)) { |
575 | sk->sk_cgrp = cg_proto; |
576 | } |
577 | rcu_read_unlock(); |
578 | } |
579 | } |
580 | EXPORT_SYMBOL(sock_update_memcg); |
581 | |
582 | void sock_release_memcg(struct sock *sk) |
583 | { |
584 | if (mem_cgroup_sockets_enabled && sk->sk_cgrp) { |
585 | struct mem_cgroup *memcg; |
586 | WARN_ON(!sk->sk_cgrp->memcg); |
587 | memcg = sk->sk_cgrp->memcg; |
588 | css_put(&sk->sk_cgrp->memcg->css); |
589 | } |
590 | } |
591 | |
592 | struct cg_proto *tcp_proto_cgroup(struct mem_cgroup *memcg) |
593 | { |
594 | if (!memcg || mem_cgroup_is_root(memcg)) |
595 | return NULL; |
596 | |
597 | return &memcg->tcp_mem; |
598 | } |
599 | EXPORT_SYMBOL(tcp_proto_cgroup); |
600 | |
601 | static void disarm_sock_keys(struct mem_cgroup *memcg) |
602 | { |
603 | if (!memcg_proto_activated(&memcg->tcp_mem)) |
604 | return; |
605 | static_key_slow_dec(&memcg_socket_limit_enabled); |
606 | } |
607 | #else |
608 | static void disarm_sock_keys(struct mem_cgroup *memcg) |
609 | { |
610 | } |
611 | #endif |
612 | |
613 | #ifdef CONFIG_MEMCG_KMEM |
614 | /* |
615 | * This will be the memcg's index in each cache's ->memcg_params->memcg_caches. |
616 | * The main reason for not using cgroup id for this: |
617 | * this works better in sparse environments, where we have a lot of memcgs, |
618 | * but only a few kmem-limited. Or also, if we have, for instance, 200 |
619 | * memcgs, and none but the 200th is kmem-limited, we'd have to have a |
620 | * 200 entry array for that. |
621 | * |
622 | * The current size of the caches array is stored in |
623 | * memcg_limited_groups_array_size. It will double each time we have to |
624 | * increase it. |
625 | */ |
626 | static DEFINE_IDA(kmem_limited_groups); |
627 | int memcg_limited_groups_array_size; |
628 | |
629 | /* |
630 | * MIN_SIZE is different than 1, because we would like to avoid going through |
631 | * the alloc/free process all the time. In a small machine, 4 kmem-limited |
632 | * cgroups is a reasonable guess. In the future, it could be a parameter or |
633 | * tunable, but that is strictly not necessary. |
634 | * |
635 | * MAX_SIZE should be as large as the number of cgrp_ids. Ideally, we could get |
636 | * this constant directly from cgroup, but it is understandable that this is |
637 | * better kept as an internal representation in cgroup.c. In any case, the |
638 | * cgrp_id space is not getting any smaller, and we don't have to necessarily |
639 | * increase ours as well if it increases. |
640 | */ |
641 | #define MEMCG_CACHES_MIN_SIZE 4 |
642 | #define MEMCG_CACHES_MAX_SIZE MEM_CGROUP_ID_MAX |
643 | |
644 | /* |
645 | * A lot of the calls to the cache allocation functions are expected to be |
646 | * inlined by the compiler. Since the calls to memcg_kmem_get_cache are |
647 | * conditional to this static branch, we'll have to allow modules that does |
648 | * kmem_cache_alloc and the such to see this symbol as well |
649 | */ |
650 | struct static_key memcg_kmem_enabled_key; |
651 | EXPORT_SYMBOL(memcg_kmem_enabled_key); |
652 | |
653 | static void disarm_kmem_keys(struct mem_cgroup *memcg) |
654 | { |
655 | if (memcg_kmem_is_active(memcg)) { |
656 | static_key_slow_dec(&memcg_kmem_enabled_key); |
657 | ida_simple_remove(&kmem_limited_groups, memcg->kmemcg_id); |
658 | } |
659 | /* |
660 | * This check can't live in kmem destruction function, |
661 | * since the charges will outlive the cgroup |
662 | */ |
663 | WARN_ON(res_counter_read_u64(&memcg->kmem, RES_USAGE) != 0); |
664 | } |
665 | #else |
666 | static void disarm_kmem_keys(struct mem_cgroup *memcg) |
667 | { |
668 | } |
669 | #endif /* CONFIG_MEMCG_KMEM */ |
670 | |
671 | static void disarm_static_keys(struct mem_cgroup *memcg) |
672 | { |
673 | disarm_sock_keys(memcg); |
674 | disarm_kmem_keys(memcg); |
675 | } |
676 | |
677 | static void drain_all_stock_async(struct mem_cgroup *memcg); |
678 | |
679 | static struct mem_cgroup_per_zone * |
680 | mem_cgroup_zoneinfo(struct mem_cgroup *memcg, int nid, int zid) |
681 | { |
682 | VM_BUG_ON((unsigned)nid >= nr_node_ids); |
683 | return &memcg->nodeinfo[nid]->zoneinfo[zid]; |
684 | } |
685 | |
686 | struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *memcg) |
687 | { |
688 | return &memcg->css; |
689 | } |
690 | |
691 | static struct mem_cgroup_per_zone * |
692 | page_cgroup_zoneinfo(struct mem_cgroup *memcg, struct page *page) |
693 | { |
694 | int nid = page_to_nid(page); |
695 | int zid = page_zonenum(page); |
696 | |
697 | return mem_cgroup_zoneinfo(memcg, nid, zid); |
698 | } |
699 | |
700 | static struct mem_cgroup_tree_per_zone * |
701 | soft_limit_tree_node_zone(int nid, int zid) |
702 | { |
703 | return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid]; |
704 | } |
705 | |
706 | static struct mem_cgroup_tree_per_zone * |
707 | soft_limit_tree_from_page(struct page *page) |
708 | { |
709 | int nid = page_to_nid(page); |
710 | int zid = page_zonenum(page); |
711 | |
712 | return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid]; |
713 | } |
714 | |
715 | static void |
716 | __mem_cgroup_insert_exceeded(struct mem_cgroup *memcg, |
717 | struct mem_cgroup_per_zone *mz, |
718 | struct mem_cgroup_tree_per_zone *mctz, |
719 | unsigned long long new_usage_in_excess) |
720 | { |
721 | struct rb_node **p = &mctz->rb_root.rb_node; |
722 | struct rb_node *parent = NULL; |
723 | struct mem_cgroup_per_zone *mz_node; |
724 | |
725 | if (mz->on_tree) |
726 | return; |
727 | |
728 | mz->usage_in_excess = new_usage_in_excess; |
729 | if (!mz->usage_in_excess) |
730 | return; |
731 | while (*p) { |
732 | parent = *p; |
733 | mz_node = rb_entry(parent, struct mem_cgroup_per_zone, |
734 | tree_node); |
735 | if (mz->usage_in_excess < mz_node->usage_in_excess) |
736 | p = &(*p)->rb_left; |
737 | /* |
738 | * We can't avoid mem cgroups that are over their soft |
739 | * limit by the same amount |
740 | */ |
741 | else if (mz->usage_in_excess >= mz_node->usage_in_excess) |
742 | p = &(*p)->rb_right; |
743 | } |
744 | rb_link_node(&mz->tree_node, parent, p); |
745 | rb_insert_color(&mz->tree_node, &mctz->rb_root); |
746 | mz->on_tree = true; |
747 | } |
748 | |
749 | static void |
750 | __mem_cgroup_remove_exceeded(struct mem_cgroup *memcg, |
751 | struct mem_cgroup_per_zone *mz, |
752 | struct mem_cgroup_tree_per_zone *mctz) |
753 | { |
754 | if (!mz->on_tree) |
755 | return; |
756 | rb_erase(&mz->tree_node, &mctz->rb_root); |
757 | mz->on_tree = false; |
758 | } |
759 | |
760 | static void |
761 | mem_cgroup_remove_exceeded(struct mem_cgroup *memcg, |
762 | struct mem_cgroup_per_zone *mz, |
763 | struct mem_cgroup_tree_per_zone *mctz) |
764 | { |
765 | spin_lock(&mctz->lock); |
766 | __mem_cgroup_remove_exceeded(memcg, mz, mctz); |
767 | spin_unlock(&mctz->lock); |
768 | } |
769 | |
770 | |
771 | static void mem_cgroup_update_tree(struct mem_cgroup *memcg, struct page *page) |
772 | { |
773 | unsigned long long excess; |
774 | struct mem_cgroup_per_zone *mz; |
775 | struct mem_cgroup_tree_per_zone *mctz; |
776 | int nid = page_to_nid(page); |
777 | int zid = page_zonenum(page); |
778 | mctz = soft_limit_tree_from_page(page); |
779 | |
780 | /* |
781 | * Necessary to update all ancestors when hierarchy is used. |
782 | * because their event counter is not touched. |
783 | */ |
784 | for (; memcg; memcg = parent_mem_cgroup(memcg)) { |
785 | mz = mem_cgroup_zoneinfo(memcg, nid, zid); |
786 | excess = res_counter_soft_limit_excess(&memcg->res); |
787 | /* |
788 | * We have to update the tree if mz is on RB-tree or |
789 | * mem is over its softlimit. |
790 | */ |
791 | if (excess || mz->on_tree) { |
792 | spin_lock(&mctz->lock); |
793 | /* if on-tree, remove it */ |
794 | if (mz->on_tree) |
795 | __mem_cgroup_remove_exceeded(memcg, mz, mctz); |
796 | /* |
797 | * Insert again. mz->usage_in_excess will be updated. |
798 | * If excess is 0, no tree ops. |
799 | */ |
800 | __mem_cgroup_insert_exceeded(memcg, mz, mctz, excess); |
801 | spin_unlock(&mctz->lock); |
802 | } |
803 | } |
804 | } |
805 | |
806 | static void mem_cgroup_remove_from_trees(struct mem_cgroup *memcg) |
807 | { |
808 | int node, zone; |
809 | struct mem_cgroup_per_zone *mz; |
810 | struct mem_cgroup_tree_per_zone *mctz; |
811 | |
812 | for_each_node(node) { |
813 | for (zone = 0; zone < MAX_NR_ZONES; zone++) { |
814 | mz = mem_cgroup_zoneinfo(memcg, node, zone); |
815 | mctz = soft_limit_tree_node_zone(node, zone); |
816 | mem_cgroup_remove_exceeded(memcg, mz, mctz); |
817 | } |
818 | } |
819 | } |
820 | |
821 | static struct mem_cgroup_per_zone * |
822 | __mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz) |
823 | { |
824 | struct rb_node *rightmost = NULL; |
825 | struct mem_cgroup_per_zone *mz; |
826 | |
827 | retry: |
828 | mz = NULL; |
829 | rightmost = rb_last(&mctz->rb_root); |
830 | if (!rightmost) |
831 | goto done; /* Nothing to reclaim from */ |
832 | |
833 | mz = rb_entry(rightmost, struct mem_cgroup_per_zone, tree_node); |
834 | /* |
835 | * Remove the node now but someone else can add it back, |
836 | * we will to add it back at the end of reclaim to its correct |
837 | * position in the tree. |
838 | */ |
839 | __mem_cgroup_remove_exceeded(mz->memcg, mz, mctz); |
840 | if (!res_counter_soft_limit_excess(&mz->memcg->res) || |
841 | !css_tryget(&mz->memcg->css)) |
842 | goto retry; |
843 | done: |
844 | return mz; |
845 | } |
846 | |
847 | static struct mem_cgroup_per_zone * |
848 | mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz) |
849 | { |
850 | struct mem_cgroup_per_zone *mz; |
851 | |
852 | spin_lock(&mctz->lock); |
853 | mz = __mem_cgroup_largest_soft_limit_node(mctz); |
854 | spin_unlock(&mctz->lock); |
855 | return mz; |
856 | } |
857 | |
858 | /* |
859 | * Implementation Note: reading percpu statistics for memcg. |
860 | * |
861 | * Both of vmstat[] and percpu_counter has threshold and do periodic |
862 | * synchronization to implement "quick" read. There are trade-off between |
863 | * reading cost and precision of value. Then, we may have a chance to implement |
864 | * a periodic synchronizion of counter in memcg's counter. |
865 | * |
866 | * But this _read() function is used for user interface now. The user accounts |
867 | * memory usage by memory cgroup and he _always_ requires exact value because |
868 | * he accounts memory. Even if we provide quick-and-fuzzy read, we always |
869 | * have to visit all online cpus and make sum. So, for now, unnecessary |
870 | * synchronization is not implemented. (just implemented for cpu hotplug) |
871 | * |
872 | * If there are kernel internal actions which can make use of some not-exact |
873 | * value, and reading all cpu value can be performance bottleneck in some |
874 | * common workload, threashold and synchonization as vmstat[] should be |
875 | * implemented. |
876 | */ |
877 | static long mem_cgroup_read_stat(struct mem_cgroup *memcg, |
878 | enum mem_cgroup_stat_index idx) |
879 | { |
880 | long val = 0; |
881 | int cpu; |
882 | |
883 | get_online_cpus(); |
884 | for_each_online_cpu(cpu) |
885 | val += per_cpu(memcg->stat->count[idx], cpu); |
886 | #ifdef CONFIG_HOTPLUG_CPU |
887 | spin_lock(&memcg->pcp_counter_lock); |
888 | val += memcg->nocpu_base.count[idx]; |
889 | spin_unlock(&memcg->pcp_counter_lock); |
890 | #endif |
891 | put_online_cpus(); |
892 | return val; |
893 | } |
894 | |
895 | static void mem_cgroup_swap_statistics(struct mem_cgroup *memcg, |
896 | bool charge) |
897 | { |
898 | int val = (charge) ? 1 : -1; |
899 | this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_SWAP], val); |
900 | } |
901 | |
902 | static unsigned long mem_cgroup_read_events(struct mem_cgroup *memcg, |
903 | enum mem_cgroup_events_index idx) |
904 | { |
905 | unsigned long val = 0; |
906 | int cpu; |
907 | |
908 | get_online_cpus(); |
909 | for_each_online_cpu(cpu) |
910 | val += per_cpu(memcg->stat->events[idx], cpu); |
911 | #ifdef CONFIG_HOTPLUG_CPU |
912 | spin_lock(&memcg->pcp_counter_lock); |
913 | val += memcg->nocpu_base.events[idx]; |
914 | spin_unlock(&memcg->pcp_counter_lock); |
915 | #endif |
916 | put_online_cpus(); |
917 | return val; |
918 | } |
919 | |
920 | static void mem_cgroup_charge_statistics(struct mem_cgroup *memcg, |
921 | struct page *page, |
922 | bool anon, int nr_pages) |
923 | { |
924 | /* |
925 | * Here, RSS means 'mapped anon' and anon's SwapCache. Shmem/tmpfs is |
926 | * counted as CACHE even if it's on ANON LRU. |
927 | */ |
928 | if (anon) |
929 | __this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_RSS], |
930 | nr_pages); |
931 | else |
932 | __this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_CACHE], |
933 | nr_pages); |
934 | |
935 | if (PageTransHuge(page)) |
936 | __this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_RSS_HUGE], |
937 | nr_pages); |
938 | |
939 | /* pagein of a big page is an event. So, ignore page size */ |
940 | if (nr_pages > 0) |
941 | __this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGPGIN]); |
942 | else { |
943 | __this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGPGOUT]); |
944 | nr_pages = -nr_pages; /* for event */ |
945 | } |
946 | |
947 | __this_cpu_add(memcg->stat->nr_page_events, nr_pages); |
948 | } |
949 | |
950 | unsigned long |
951 | mem_cgroup_get_lru_size(struct lruvec *lruvec, enum lru_list lru) |
952 | { |
953 | struct mem_cgroup_per_zone *mz; |
954 | |
955 | mz = container_of(lruvec, struct mem_cgroup_per_zone, lruvec); |
956 | return mz->lru_size[lru]; |
957 | } |
958 | |
959 | static unsigned long |
960 | mem_cgroup_zone_nr_lru_pages(struct mem_cgroup *memcg, int nid, int zid, |
961 | unsigned int lru_mask) |
962 | { |
963 | struct mem_cgroup_per_zone *mz; |
964 | enum lru_list lru; |
965 | unsigned long ret = 0; |
966 | |
967 | mz = mem_cgroup_zoneinfo(memcg, nid, zid); |
968 | |
969 | for_each_lru(lru) { |
970 | if (BIT(lru) & lru_mask) |
971 | ret += mz->lru_size[lru]; |
972 | } |
973 | return ret; |
974 | } |
975 | |
976 | static unsigned long |
977 | mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg, |
978 | int nid, unsigned int lru_mask) |
979 | { |
980 | u64 total = 0; |
981 | int zid; |
982 | |
983 | for (zid = 0; zid < MAX_NR_ZONES; zid++) |
984 | total += mem_cgroup_zone_nr_lru_pages(memcg, |
985 | nid, zid, lru_mask); |
986 | |
987 | return total; |
988 | } |
989 | |
990 | static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup *memcg, |
991 | unsigned int lru_mask) |
992 | { |
993 | int nid; |
994 | u64 total = 0; |
995 | |
996 | for_each_node_state(nid, N_MEMORY) |
997 | total += mem_cgroup_node_nr_lru_pages(memcg, nid, lru_mask); |
998 | return total; |
999 | } |
1000 | |
1001 | static bool mem_cgroup_event_ratelimit(struct mem_cgroup *memcg, |
1002 | enum mem_cgroup_events_target target) |
1003 | { |
1004 | unsigned long val, next; |
1005 | |
1006 | val = __this_cpu_read(memcg->stat->nr_page_events); |
1007 | next = __this_cpu_read(memcg->stat->targets[target]); |
1008 | /* from time_after() in jiffies.h */ |
1009 | if ((long)next - (long)val < 0) { |
1010 | switch (target) { |
1011 | case MEM_CGROUP_TARGET_THRESH: |
1012 | next = val + THRESHOLDS_EVENTS_TARGET; |
1013 | break; |
1014 | case MEM_CGROUP_TARGET_SOFTLIMIT: |
1015 | next = val + SOFTLIMIT_EVENTS_TARGET; |
1016 | break; |
1017 | case MEM_CGROUP_TARGET_NUMAINFO: |
1018 | next = val + NUMAINFO_EVENTS_TARGET; |
1019 | break; |
1020 | default: |
1021 | break; |
1022 | } |
1023 | __this_cpu_write(memcg->stat->targets[target], next); |
1024 | return true; |
1025 | } |
1026 | return false; |
1027 | } |
1028 | |
1029 | /* |
1030 | * Check events in order. |
1031 | * |
1032 | */ |
1033 | static void memcg_check_events(struct mem_cgroup *memcg, struct page *page) |
1034 | { |
1035 | preempt_disable(); |
1036 | /* threshold event is triggered in finer grain than soft limit */ |
1037 | if (unlikely(mem_cgroup_event_ratelimit(memcg, |
1038 | MEM_CGROUP_TARGET_THRESH))) { |
1039 | bool do_softlimit; |
1040 | bool do_numainfo __maybe_unused; |
1041 | |
1042 | do_softlimit = mem_cgroup_event_ratelimit(memcg, |
1043 | MEM_CGROUP_TARGET_SOFTLIMIT); |
1044 | #if MAX_NUMNODES > 1 |
1045 | do_numainfo = mem_cgroup_event_ratelimit(memcg, |
1046 | MEM_CGROUP_TARGET_NUMAINFO); |
1047 | #endif |
1048 | preempt_enable(); |
1049 | |
1050 | mem_cgroup_threshold(memcg); |
1051 | if (unlikely(do_softlimit)) |
1052 | mem_cgroup_update_tree(memcg, page); |
1053 | #if MAX_NUMNODES > 1 |
1054 | if (unlikely(do_numainfo)) |
1055 | atomic_inc(&memcg->numainfo_events); |
1056 | #endif |
1057 | } else |
1058 | preempt_enable(); |
1059 | } |
1060 | |
1061 | struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p) |
1062 | { |
1063 | /* |
1064 | * mm_update_next_owner() may clear mm->owner to NULL |
1065 | * if it races with swapoff, page migration, etc. |
1066 | * So this can be called with p == NULL. |
1067 | */ |
1068 | if (unlikely(!p)) |
1069 | return NULL; |
1070 | |
1071 | return mem_cgroup_from_css(task_css(p, memory_cgrp_id)); |
1072 | } |
1073 | |
1074 | static struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm) |
1075 | { |
1076 | struct mem_cgroup *memcg = NULL; |
1077 | |
1078 | rcu_read_lock(); |
1079 | do { |
1080 | /* |
1081 | * Page cache insertions can happen withou an |
1082 | * actual mm context, e.g. during disk probing |
1083 | * on boot, loopback IO, acct() writes etc. |
1084 | */ |
1085 | if (unlikely(!mm)) |
1086 | memcg = root_mem_cgroup; |
1087 | else { |
1088 | memcg = mem_cgroup_from_task(rcu_dereference(mm->owner)); |
1089 | if (unlikely(!memcg)) |
1090 | memcg = root_mem_cgroup; |
1091 | } |
1092 | } while (!css_tryget(&memcg->css)); |
1093 | rcu_read_unlock(); |
1094 | return memcg; |
1095 | } |
1096 | |
1097 | /* |
1098 | * Returns a next (in a pre-order walk) alive memcg (with elevated css |
1099 | * ref. count) or NULL if the whole root's subtree has been visited. |
1100 | * |
1101 | * helper function to be used by mem_cgroup_iter |
1102 | */ |
1103 | static struct mem_cgroup *__mem_cgroup_iter_next(struct mem_cgroup *root, |
1104 | struct mem_cgroup *last_visited) |
1105 | { |
1106 | struct cgroup_subsys_state *prev_css, *next_css; |
1107 | |
1108 | prev_css = last_visited ? &last_visited->css : NULL; |
1109 | skip_node: |
1110 | next_css = css_next_descendant_pre(prev_css, &root->css); |
1111 | |
1112 | /* |
1113 | * Even if we found a group we have to make sure it is |
1114 | * alive. css && !memcg means that the groups should be |
1115 | * skipped and we should continue the tree walk. |
1116 | * last_visited css is safe to use because it is |
1117 | * protected by css_get and the tree walk is rcu safe. |
1118 | * |
1119 | * We do not take a reference on the root of the tree walk |
1120 | * because we might race with the root removal when it would |
1121 | * be the only node in the iterated hierarchy and mem_cgroup_iter |
1122 | * would end up in an endless loop because it expects that at |
1123 | * least one valid node will be returned. Root cannot disappear |
1124 | * because caller of the iterator should hold it already so |
1125 | * skipping css reference should be safe. |
1126 | */ |
1127 | if (next_css) { |
1128 | if ((next_css == &root->css) || |
1129 | ((next_css->flags & CSS_ONLINE) && css_tryget(next_css))) |
1130 | return mem_cgroup_from_css(next_css); |
1131 | |
1132 | prev_css = next_css; |
1133 | goto skip_node; |
1134 | } |
1135 | |
1136 | return NULL; |
1137 | } |
1138 | |
1139 | static void mem_cgroup_iter_invalidate(struct mem_cgroup *root) |
1140 | { |
1141 | /* |
1142 | * When a group in the hierarchy below root is destroyed, the |
1143 | * hierarchy iterator can no longer be trusted since it might |
1144 | * have pointed to the destroyed group. Invalidate it. |
1145 | */ |
1146 | atomic_inc(&root->dead_count); |
1147 | } |
1148 | |
1149 | static struct mem_cgroup * |
1150 | mem_cgroup_iter_load(struct mem_cgroup_reclaim_iter *iter, |
1151 | struct mem_cgroup *root, |
1152 | int *sequence) |
1153 | { |
1154 | struct mem_cgroup *position = NULL; |
1155 | /* |
1156 | * A cgroup destruction happens in two stages: offlining and |
1157 | * release. They are separated by a RCU grace period. |
1158 | * |
1159 | * If the iterator is valid, we may still race with an |
1160 | * offlining. The RCU lock ensures the object won't be |
1161 | * released, tryget will fail if we lost the race. |
1162 | */ |
1163 | *sequence = atomic_read(&root->dead_count); |
1164 | if (iter->last_dead_count == *sequence) { |
1165 | smp_rmb(); |
1166 | position = iter->last_visited; |
1167 | |
1168 | /* |
1169 | * We cannot take a reference to root because we might race |
1170 | * with root removal and returning NULL would end up in |
1171 | * an endless loop on the iterator user level when root |
1172 | * would be returned all the time. |
1173 | */ |
1174 | if (position && position != root && |
1175 | !css_tryget(&position->css)) |
1176 | position = NULL; |
1177 | } |
1178 | return position; |
1179 | } |
1180 | |
1181 | static void mem_cgroup_iter_update(struct mem_cgroup_reclaim_iter *iter, |
1182 | struct mem_cgroup *last_visited, |
1183 | struct mem_cgroup *new_position, |
1184 | struct mem_cgroup *root, |
1185 | int sequence) |
1186 | { |
1187 | /* root reference counting symmetric to mem_cgroup_iter_load */ |
1188 | if (last_visited && last_visited != root) |
1189 | css_put(&last_visited->css); |
1190 | /* |
1191 | * We store the sequence count from the time @last_visited was |
1192 | * loaded successfully instead of rereading it here so that we |
1193 | * don't lose destruction events in between. We could have |
1194 | * raced with the destruction of @new_position after all. |
1195 | */ |
1196 | iter->last_visited = new_position; |
1197 | smp_wmb(); |
1198 | iter->last_dead_count = sequence; |
1199 | } |
1200 | |
1201 | /** |
1202 | * mem_cgroup_iter - iterate over memory cgroup hierarchy |
1203 | * @root: hierarchy root |
1204 | * @prev: previously returned memcg, NULL on first invocation |
1205 | * @reclaim: cookie for shared reclaim walks, NULL for full walks |
1206 | * |
1207 | * Returns references to children of the hierarchy below @root, or |
1208 | * @root itself, or %NULL after a full round-trip. |
1209 | * |
1210 | * Caller must pass the return value in @prev on subsequent |
1211 | * invocations for reference counting, or use mem_cgroup_iter_break() |
1212 | * to cancel a hierarchy walk before the round-trip is complete. |
1213 | * |
1214 | * Reclaimers can specify a zone and a priority level in @reclaim to |
1215 | * divide up the memcgs in the hierarchy among all concurrent |
1216 | * reclaimers operating on the same zone and priority. |
1217 | */ |
1218 | struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root, |
1219 | struct mem_cgroup *prev, |
1220 | struct mem_cgroup_reclaim_cookie *reclaim) |
1221 | { |
1222 | struct mem_cgroup *memcg = NULL; |
1223 | struct mem_cgroup *last_visited = NULL; |
1224 | |
1225 | if (mem_cgroup_disabled()) |
1226 | return NULL; |
1227 | |
1228 | if (!root) |
1229 | root = root_mem_cgroup; |
1230 | |
1231 | if (prev && !reclaim) |
1232 | last_visited = prev; |
1233 | |
1234 | if (!root->use_hierarchy && root != root_mem_cgroup) { |
1235 | if (prev) |
1236 | goto out_css_put; |
1237 | return root; |
1238 | } |
1239 | |
1240 | rcu_read_lock(); |
1241 | while (!memcg) { |
1242 | struct mem_cgroup_reclaim_iter *uninitialized_var(iter); |
1243 | int uninitialized_var(seq); |
1244 | |
1245 | if (reclaim) { |
1246 | int nid = zone_to_nid(reclaim->zone); |
1247 | int zid = zone_idx(reclaim->zone); |
1248 | struct mem_cgroup_per_zone *mz; |
1249 | |
1250 | mz = mem_cgroup_zoneinfo(root, nid, zid); |
1251 | iter = &mz->reclaim_iter[reclaim->priority]; |
1252 | if (prev && reclaim->generation != iter->generation) { |
1253 | iter->last_visited = NULL; |
1254 | goto out_unlock; |
1255 | } |
1256 | |
1257 | last_visited = mem_cgroup_iter_load(iter, root, &seq); |
1258 | } |
1259 | |
1260 | memcg = __mem_cgroup_iter_next(root, last_visited); |
1261 | |
1262 | if (reclaim) { |
1263 | mem_cgroup_iter_update(iter, last_visited, memcg, root, |
1264 | seq); |
1265 | |
1266 | if (!memcg) |
1267 | iter->generation++; |
1268 | else if (!prev && memcg) |
1269 | reclaim->generation = iter->generation; |
1270 | } |
1271 | |
1272 | if (prev && !memcg) |
1273 | goto out_unlock; |
1274 | } |
1275 | out_unlock: |
1276 | rcu_read_unlock(); |
1277 | out_css_put: |
1278 | if (prev && prev != root) |
1279 | css_put(&prev->css); |
1280 | |
1281 | return memcg; |
1282 | } |
1283 | |
1284 | /** |
1285 | * mem_cgroup_iter_break - abort a hierarchy walk prematurely |
1286 | * @root: hierarchy root |
1287 | * @prev: last visited hierarchy member as returned by mem_cgroup_iter() |
1288 | */ |
1289 | void mem_cgroup_iter_break(struct mem_cgroup *root, |
1290 | struct mem_cgroup *prev) |
1291 | { |
1292 | if (!root) |
1293 | root = root_mem_cgroup; |
1294 | if (prev && prev != root) |
1295 | css_put(&prev->css); |
1296 | } |
1297 | |
1298 | /* |
1299 | * Iteration constructs for visiting all cgroups (under a tree). If |
1300 | * loops are exited prematurely (break), mem_cgroup_iter_break() must |
1301 | * be used for reference counting. |
1302 | */ |
1303 | #define for_each_mem_cgroup_tree(iter, root) \ |
1304 | for (iter = mem_cgroup_iter(root, NULL, NULL); \ |
1305 | iter != NULL; \ |
1306 | iter = mem_cgroup_iter(root, iter, NULL)) |
1307 | |
1308 | #define for_each_mem_cgroup(iter) \ |
1309 | for (iter = mem_cgroup_iter(NULL, NULL, NULL); \ |
1310 | iter != NULL; \ |
1311 | iter = mem_cgroup_iter(NULL, iter, NULL)) |
1312 | |
1313 | void __mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx) |
1314 | { |
1315 | struct mem_cgroup *memcg; |
1316 | |
1317 | rcu_read_lock(); |
1318 | memcg = mem_cgroup_from_task(rcu_dereference(mm->owner)); |
1319 | if (unlikely(!memcg)) |
1320 | goto out; |
1321 | |
1322 | switch (idx) { |
1323 | case PGFAULT: |
1324 | this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGFAULT]); |
1325 | break; |
1326 | case PGMAJFAULT: |
1327 | this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGMAJFAULT]); |
1328 | break; |
1329 | default: |
1330 | BUG(); |
1331 | } |
1332 | out: |
1333 | rcu_read_unlock(); |
1334 | } |
1335 | EXPORT_SYMBOL(__mem_cgroup_count_vm_event); |
1336 | |
1337 | /** |
1338 | * mem_cgroup_zone_lruvec - get the lru list vector for a zone and memcg |
1339 | * @zone: zone of the wanted lruvec |
1340 | * @memcg: memcg of the wanted lruvec |
1341 | * |
1342 | * Returns the lru list vector holding pages for the given @zone and |
1343 | * @mem. This can be the global zone lruvec, if the memory controller |
1344 | * is disabled. |
1345 | */ |
1346 | struct lruvec *mem_cgroup_zone_lruvec(struct zone *zone, |
1347 | struct mem_cgroup *memcg) |
1348 | { |
1349 | struct mem_cgroup_per_zone *mz; |
1350 | struct lruvec *lruvec; |
1351 | |
1352 | if (mem_cgroup_disabled()) { |
1353 | lruvec = &zone->lruvec; |
1354 | goto out; |
1355 | } |
1356 | |
1357 | mz = mem_cgroup_zoneinfo(memcg, zone_to_nid(zone), zone_idx(zone)); |
1358 | lruvec = &mz->lruvec; |
1359 | out: |
1360 | /* |
1361 | * Since a node can be onlined after the mem_cgroup was created, |
1362 | * we have to be prepared to initialize lruvec->zone here; |
1363 | * and if offlined then reonlined, we need to reinitialize it. |
1364 | */ |
1365 | if (unlikely(lruvec->zone != zone)) |
1366 | lruvec->zone = zone; |
1367 | return lruvec; |
1368 | } |
1369 | |
1370 | /* |
1371 | * Following LRU functions are allowed to be used without PCG_LOCK. |
1372 | * Operations are called by routine of global LRU independently from memcg. |
1373 | * What we have to take care of here is validness of pc->mem_cgroup. |
1374 | * |
1375 | * Changes to pc->mem_cgroup happens when |
1376 | * 1. charge |
1377 | * 2. moving account |
1378 | * In typical case, "charge" is done before add-to-lru. Exception is SwapCache. |
1379 | * It is added to LRU before charge. |
1380 | * If PCG_USED bit is not set, page_cgroup is not added to this private LRU. |
1381 | * When moving account, the page is not on LRU. It's isolated. |
1382 | */ |
1383 | |
1384 | /** |
1385 | * mem_cgroup_page_lruvec - return lruvec for adding an lru page |
1386 | * @page: the page |
1387 | * @zone: zone of the page |
1388 | */ |
1389 | struct lruvec *mem_cgroup_page_lruvec(struct page *page, struct zone *zone) |
1390 | { |
1391 | struct mem_cgroup_per_zone *mz; |
1392 | struct mem_cgroup *memcg; |
1393 | struct page_cgroup *pc; |
1394 | struct lruvec *lruvec; |
1395 | |
1396 | if (mem_cgroup_disabled()) { |
1397 | lruvec = &zone->lruvec; |
1398 | goto out; |
1399 | } |
1400 | |
1401 | pc = lookup_page_cgroup(page); |
1402 | memcg = pc->mem_cgroup; |
1403 | |
1404 | /* |
1405 | * Surreptitiously switch any uncharged offlist page to root: |
1406 | * an uncharged page off lru does nothing to secure |
1407 | * its former mem_cgroup from sudden removal. |
1408 | * |
1409 | * Our caller holds lru_lock, and PageCgroupUsed is updated |
1410 | * under page_cgroup lock: between them, they make all uses |
1411 | * of pc->mem_cgroup safe. |
1412 | */ |
1413 | if (!PageLRU(page) && !PageCgroupUsed(pc) && memcg != root_mem_cgroup) |
1414 | pc->mem_cgroup = memcg = root_mem_cgroup; |
1415 | |
1416 | mz = page_cgroup_zoneinfo(memcg, page); |
1417 | lruvec = &mz->lruvec; |
1418 | out: |
1419 | /* |
1420 | * Since a node can be onlined after the mem_cgroup was created, |
1421 | * we have to be prepared to initialize lruvec->zone here; |
1422 | * and if offlined then reonlined, we need to reinitialize it. |
1423 | */ |
1424 | if (unlikely(lruvec->zone != zone)) |
1425 | lruvec->zone = zone; |
1426 | return lruvec; |
1427 | } |
1428 | |
1429 | /** |
1430 | * mem_cgroup_update_lru_size - account for adding or removing an lru page |
1431 | * @lruvec: mem_cgroup per zone lru vector |
1432 | * @lru: index of lru list the page is sitting on |
1433 | * @nr_pages: positive when adding or negative when removing |
1434 | * |
1435 | * This function must be called when a page is added to or removed from an |
1436 | * lru list. |
1437 | */ |
1438 | void mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru, |
1439 | int nr_pages) |
1440 | { |
1441 | struct mem_cgroup_per_zone *mz; |
1442 | unsigned long *lru_size; |
1443 | |
1444 | if (mem_cgroup_disabled()) |
1445 | return; |
1446 | |
1447 | mz = container_of(lruvec, struct mem_cgroup_per_zone, lruvec); |
1448 | lru_size = mz->lru_size + lru; |
1449 | *lru_size += nr_pages; |
1450 | VM_BUG_ON((long)(*lru_size) < 0); |
1451 | } |
1452 | |
1453 | /* |
1454 | * Checks whether given mem is same or in the root_mem_cgroup's |
1455 | * hierarchy subtree |
1456 | */ |
1457 | bool __mem_cgroup_same_or_subtree(const struct mem_cgroup *root_memcg, |
1458 | struct mem_cgroup *memcg) |
1459 | { |
1460 | if (root_memcg == memcg) |
1461 | return true; |
1462 | if (!root_memcg->use_hierarchy || !memcg) |
1463 | return false; |
1464 | return cgroup_is_descendant(memcg->css.cgroup, root_memcg->css.cgroup); |
1465 | } |
1466 | |
1467 | static bool mem_cgroup_same_or_subtree(const struct mem_cgroup *root_memcg, |
1468 | struct mem_cgroup *memcg) |
1469 | { |
1470 | bool ret; |
1471 | |
1472 | rcu_read_lock(); |
1473 | ret = __mem_cgroup_same_or_subtree(root_memcg, memcg); |
1474 | rcu_read_unlock(); |
1475 | return ret; |
1476 | } |
1477 | |
1478 | bool task_in_mem_cgroup(struct task_struct *task, |
1479 | const struct mem_cgroup *memcg) |
1480 | { |
1481 | struct mem_cgroup *curr = NULL; |
1482 | struct task_struct *p; |
1483 | bool ret; |
1484 | |
1485 | p = find_lock_task_mm(task); |
1486 | if (p) { |
1487 | curr = get_mem_cgroup_from_mm(p->mm); |
1488 | task_unlock(p); |
1489 | } else { |
1490 | /* |
1491 | * All threads may have already detached their mm's, but the oom |
1492 | * killer still needs to detect if they have already been oom |
1493 | * killed to prevent needlessly killing additional tasks. |
1494 | */ |
1495 | rcu_read_lock(); |
1496 | curr = mem_cgroup_from_task(task); |
1497 | if (curr) |
1498 | css_get(&curr->css); |
1499 | rcu_read_unlock(); |
1500 | } |
1501 | /* |
1502 | * We should check use_hierarchy of "memcg" not "curr". Because checking |
1503 | * use_hierarchy of "curr" here make this function true if hierarchy is |
1504 | * enabled in "curr" and "curr" is a child of "memcg" in *cgroup* |
1505 | * hierarchy(even if use_hierarchy is disabled in "memcg"). |
1506 | */ |
1507 | ret = mem_cgroup_same_or_subtree(memcg, curr); |
1508 | css_put(&curr->css); |
1509 | return ret; |
1510 | } |
1511 | |
1512 | int mem_cgroup_inactive_anon_is_low(struct lruvec *lruvec) |
1513 | { |
1514 | unsigned long inactive_ratio; |
1515 | unsigned long inactive; |
1516 | unsigned long active; |
1517 | unsigned long gb; |
1518 | |
1519 | inactive = mem_cgroup_get_lru_size(lruvec, LRU_INACTIVE_ANON); |
1520 | active = mem_cgroup_get_lru_size(lruvec, LRU_ACTIVE_ANON); |
1521 | |
1522 | gb = (inactive + active) >> (30 - PAGE_SHIFT); |
1523 | if (gb) |
1524 | inactive_ratio = int_sqrt(10 * gb); |
1525 | else |
1526 | inactive_ratio = 1; |
1527 | |
1528 | return inactive * inactive_ratio < active; |
1529 | } |
1530 | |
1531 | #define mem_cgroup_from_res_counter(counter, member) \ |
1532 | container_of(counter, struct mem_cgroup, member) |
1533 | |
1534 | /** |
1535 | * mem_cgroup_margin - calculate chargeable space of a memory cgroup |
1536 | * @memcg: the memory cgroup |
1537 | * |
1538 | * Returns the maximum amount of memory @mem can be charged with, in |
1539 | * pages. |
1540 | */ |
1541 | static unsigned long mem_cgroup_margin(struct mem_cgroup *memcg) |
1542 | { |
1543 | unsigned long long margin; |
1544 | |
1545 | margin = res_counter_margin(&memcg->res); |
1546 | if (do_swap_account) |
1547 | margin = min(margin, res_counter_margin(&memcg->memsw)); |
1548 | return margin >> PAGE_SHIFT; |
1549 | } |
1550 | |
1551 | int mem_cgroup_swappiness(struct mem_cgroup *memcg) |
1552 | { |
1553 | /* root ? */ |
1554 | if (!css_parent(&memcg->css)) |
1555 | return vm_swappiness; |
1556 | |
1557 | return memcg->swappiness; |
1558 | } |
1559 | |
1560 | /* |
1561 | * memcg->moving_account is used for checking possibility that some thread is |
1562 | * calling move_account(). When a thread on CPU-A starts moving pages under |
1563 | * a memcg, other threads should check memcg->moving_account under |
1564 | * rcu_read_lock(), like this: |
1565 | * |
1566 | * CPU-A CPU-B |
1567 | * rcu_read_lock() |
1568 | * memcg->moving_account+1 if (memcg->mocing_account) |
1569 | * take heavy locks. |
1570 | * synchronize_rcu() update something. |
1571 | * rcu_read_unlock() |
1572 | * start move here. |
1573 | */ |
1574 | |
1575 | /* for quick checking without looking up memcg */ |
1576 | atomic_t memcg_moving __read_mostly; |
1577 | |
1578 | static void mem_cgroup_start_move(struct mem_cgroup *memcg) |
1579 | { |
1580 | atomic_inc(&memcg_moving); |
1581 | atomic_inc(&memcg->moving_account); |
1582 | synchronize_rcu(); |
1583 | } |
1584 | |
1585 | static void mem_cgroup_end_move(struct mem_cgroup *memcg) |
1586 | { |
1587 | /* |
1588 | * Now, mem_cgroup_clear_mc() may call this function with NULL. |
1589 | * We check NULL in callee rather than caller. |
1590 | */ |
1591 | if (memcg) { |
1592 | atomic_dec(&memcg_moving); |
1593 | atomic_dec(&memcg->moving_account); |
1594 | } |
1595 | } |
1596 | |
1597 | /* |
1598 | * 2 routines for checking "mem" is under move_account() or not. |
1599 | * |
1600 | * mem_cgroup_stolen() - checking whether a cgroup is mc.from or not. This |
1601 | * is used for avoiding races in accounting. If true, |
1602 | * pc->mem_cgroup may be overwritten. |
1603 | * |
1604 | * mem_cgroup_under_move() - checking a cgroup is mc.from or mc.to or |
1605 | * under hierarchy of moving cgroups. This is for |
1606 | * waiting at hith-memory prressure caused by "move". |
1607 | */ |
1608 | |
1609 | static bool mem_cgroup_stolen(struct mem_cgroup *memcg) |
1610 | { |
1611 | VM_BUG_ON(!rcu_read_lock_held()); |
1612 | return atomic_read(&memcg->moving_account) > 0; |
1613 | } |
1614 | |
1615 | static bool mem_cgroup_under_move(struct mem_cgroup *memcg) |
1616 | { |
1617 | struct mem_cgroup *from; |
1618 | struct mem_cgroup *to; |
1619 | bool ret = false; |
1620 | /* |
1621 | * Unlike task_move routines, we access mc.to, mc.from not under |
1622 | * mutual exclusion by cgroup_mutex. Here, we take spinlock instead. |
1623 | */ |
1624 | spin_lock(&mc.lock); |
1625 | from = mc.from; |
1626 | to = mc.to; |
1627 | if (!from) |
1628 | goto unlock; |
1629 | |
1630 | ret = mem_cgroup_same_or_subtree(memcg, from) |
1631 | || mem_cgroup_same_or_subtree(memcg, to); |
1632 | unlock: |
1633 | spin_unlock(&mc.lock); |
1634 | return ret; |
1635 | } |
1636 | |
1637 | static bool mem_cgroup_wait_acct_move(struct mem_cgroup *memcg) |
1638 | { |
1639 | if (mc.moving_task && current != mc.moving_task) { |
1640 | if (mem_cgroup_under_move(memcg)) { |
1641 | DEFINE_WAIT(wait); |
1642 | prepare_to_wait(&mc.waitq, &wait, TASK_INTERRUPTIBLE); |
1643 | /* moving charge context might have finished. */ |
1644 | if (mc.moving_task) |
1645 | schedule(); |
1646 | finish_wait(&mc.waitq, &wait); |
1647 | return true; |
1648 | } |
1649 | } |
1650 | return false; |
1651 | } |
1652 | |
1653 | /* |
1654 | * Take this lock when |
1655 | * - a code tries to modify page's memcg while it's USED. |
1656 | * - a code tries to modify page state accounting in a memcg. |
1657 | * see mem_cgroup_stolen(), too. |
1658 | */ |
1659 | static void move_lock_mem_cgroup(struct mem_cgroup *memcg, |
1660 | unsigned long *flags) |
1661 | { |
1662 | spin_lock_irqsave(&memcg->move_lock, *flags); |
1663 | } |
1664 | |
1665 | static void move_unlock_mem_cgroup(struct mem_cgroup *memcg, |
1666 | unsigned long *flags) |
1667 | { |
1668 | spin_unlock_irqrestore(&memcg->move_lock, *flags); |
1669 | } |
1670 | |
1671 | #define K(x) ((x) << (PAGE_SHIFT-10)) |
1672 | /** |
1673 | * mem_cgroup_print_oom_info: Print OOM information relevant to memory controller. |
1674 | * @memcg: The memory cgroup that went over limit |
1675 | * @p: Task that is going to be killed |
1676 | * |
1677 | * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is |
1678 | * enabled |
1679 | */ |
1680 | void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p) |
1681 | { |
1682 | /* oom_info_lock ensures that parallel ooms do not interleave */ |
1683 | static DEFINE_MUTEX(oom_info_lock); |
1684 | struct mem_cgroup *iter; |
1685 | unsigned int i; |
1686 | |
1687 | if (!p) |
1688 | return; |
1689 | |
1690 | mutex_lock(&oom_info_lock); |
1691 | rcu_read_lock(); |
1692 | |
1693 | pr_info("Task in "); |
1694 | pr_cont_cgroup_path(task_cgroup(p, memory_cgrp_id)); |
1695 | pr_info(" killed as a result of limit of "); |
1696 | pr_cont_cgroup_path(memcg->css.cgroup); |
1697 | pr_info("\n"); |
1698 | |
1699 | rcu_read_unlock(); |
1700 | |
1701 | pr_info("memory: usage %llukB, limit %llukB, failcnt %llu\n", |
1702 | res_counter_read_u64(&memcg->res, RES_USAGE) >> 10, |
1703 | res_counter_read_u64(&memcg->res, RES_LIMIT) >> 10, |
1704 | res_counter_read_u64(&memcg->res, RES_FAILCNT)); |
1705 | pr_info("memory+swap: usage %llukB, limit %llukB, failcnt %llu\n", |
1706 | res_counter_read_u64(&memcg->memsw, RES_USAGE) >> 10, |
1707 | res_counter_read_u64(&memcg->memsw, RES_LIMIT) >> 10, |
1708 | res_counter_read_u64(&memcg->memsw, RES_FAILCNT)); |
1709 | pr_info("kmem: usage %llukB, limit %llukB, failcnt %llu\n", |
1710 | res_counter_read_u64(&memcg->kmem, RES_USAGE) >> 10, |
1711 | res_counter_read_u64(&memcg->kmem, RES_LIMIT) >> 10, |
1712 | res_counter_read_u64(&memcg->kmem, RES_FAILCNT)); |
1713 | |
1714 | for_each_mem_cgroup_tree(iter, memcg) { |
1715 | pr_info("Memory cgroup stats for "); |
1716 | pr_cont_cgroup_path(iter->css.cgroup); |
1717 | pr_cont(":"); |
1718 | |
1719 | for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) { |
1720 | if (i == MEM_CGROUP_STAT_SWAP && !do_swap_account) |
1721 | continue; |
1722 | pr_cont(" %s:%ldKB", mem_cgroup_stat_names[i], |
1723 | K(mem_cgroup_read_stat(iter, i))); |
1724 | } |
1725 | |
1726 | for (i = 0; i < NR_LRU_LISTS; i++) |
1727 | pr_cont(" %s:%luKB", mem_cgroup_lru_names[i], |
1728 | K(mem_cgroup_nr_lru_pages(iter, BIT(i)))); |
1729 | |
1730 | pr_cont("\n"); |
1731 | } |
1732 | mutex_unlock(&oom_info_lock); |
1733 | } |
1734 | |
1735 | /* |
1736 | * This function returns the number of memcg under hierarchy tree. Returns |
1737 | * 1(self count) if no children. |
1738 | */ |
1739 | static int mem_cgroup_count_children(struct mem_cgroup *memcg) |
1740 | { |
1741 | int num = 0; |
1742 | struct mem_cgroup *iter; |
1743 | |
1744 | for_each_mem_cgroup_tree(iter, memcg) |
1745 | num++; |
1746 | return num; |
1747 | } |
1748 | |
1749 | /* |
1750 | * Return the memory (and swap, if configured) limit for a memcg. |
1751 | */ |
1752 | static u64 mem_cgroup_get_limit(struct mem_cgroup *memcg) |
1753 | { |
1754 | u64 limit; |
1755 | |
1756 | limit = res_counter_read_u64(&memcg->res, RES_LIMIT); |
1757 | |
1758 | /* |
1759 | * Do not consider swap space if we cannot swap due to swappiness |
1760 | */ |
1761 | if (mem_cgroup_swappiness(memcg)) { |
1762 | u64 memsw; |
1763 | |
1764 | limit += total_swap_pages << PAGE_SHIFT; |
1765 | memsw = res_counter_read_u64(&memcg->memsw, RES_LIMIT); |
1766 | |
1767 | /* |
1768 | * If memsw is finite and limits the amount of swap space |
1769 | * available to this memcg, return that limit. |
1770 | */ |
1771 | limit = min(limit, memsw); |
1772 | } |
1773 | |
1774 | return limit; |
1775 | } |
1776 | |
1777 | static void mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask, |
1778 | int order) |
1779 | { |
1780 | struct mem_cgroup *iter; |
1781 | unsigned long chosen_points = 0; |
1782 | unsigned long totalpages; |
1783 | unsigned int points = 0; |
1784 | struct task_struct *chosen = NULL; |
1785 | |
1786 | /* |
1787 | * If current has a pending SIGKILL or is exiting, then automatically |
1788 | * select it. The goal is to allow it to allocate so that it may |
1789 | * quickly exit and free its memory. |
1790 | */ |
1791 | if (fatal_signal_pending(current) || current->flags & PF_EXITING) { |
1792 | set_thread_flag(TIF_MEMDIE); |
1793 | return; |
1794 | } |
1795 | |
1796 | check_panic_on_oom(CONSTRAINT_MEMCG, gfp_mask, order, NULL); |
1797 | totalpages = mem_cgroup_get_limit(memcg) >> PAGE_SHIFT ? : 1; |
1798 | for_each_mem_cgroup_tree(iter, memcg) { |
1799 | struct css_task_iter it; |
1800 | struct task_struct *task; |
1801 | |
1802 | css_task_iter_start(&iter->css, &it); |
1803 | while ((task = css_task_iter_next(&it))) { |
1804 | switch (oom_scan_process_thread(task, totalpages, NULL, |
1805 | false)) { |
1806 | case OOM_SCAN_SELECT: |
1807 | if (chosen) |
1808 | put_task_struct(chosen); |
1809 | chosen = task; |
1810 | chosen_points = ULONG_MAX; |
1811 | get_task_struct(chosen); |
1812 | /* fall through */ |
1813 | case OOM_SCAN_CONTINUE: |
1814 | continue; |
1815 | case OOM_SCAN_ABORT: |
1816 | css_task_iter_end(&it); |
1817 | mem_cgroup_iter_break(memcg, iter); |
1818 | if (chosen) |
1819 | put_task_struct(chosen); |
1820 | return; |
1821 | case OOM_SCAN_OK: |
1822 | break; |
1823 | }; |
1824 | points = oom_badness(task, memcg, NULL, totalpages); |
1825 | if (!points || points < chosen_points) |
1826 | continue; |
1827 | /* Prefer thread group leaders for display purposes */ |
1828 | if (points == chosen_points && |
1829 | thread_group_leader(chosen)) |
1830 | continue; |
1831 | |
1832 | if (chosen) |
1833 | put_task_struct(chosen); |
1834 | chosen = task; |
1835 | chosen_points = points; |
1836 | get_task_struct(chosen); |
1837 | } |
1838 | css_task_iter_end(&it); |
1839 | } |
1840 | |
1841 | if (!chosen) |
1842 | return; |
1843 | points = chosen_points * 1000 / totalpages; |
1844 | oom_kill_process(chosen, gfp_mask, order, points, totalpages, memcg, |
1845 | NULL, "Memory cgroup out of memory"); |
1846 | } |
1847 | |
1848 | static unsigned long mem_cgroup_reclaim(struct mem_cgroup *memcg, |
1849 | gfp_t gfp_mask, |
1850 | unsigned long flags) |
1851 | { |
1852 | unsigned long total = 0; |
1853 | bool noswap = false; |
1854 | int loop; |
1855 | |
1856 | if (flags & MEM_CGROUP_RECLAIM_NOSWAP) |
1857 | noswap = true; |
1858 | if (!(flags & MEM_CGROUP_RECLAIM_SHRINK) && memcg->memsw_is_minimum) |
1859 | noswap = true; |
1860 | |
1861 | for (loop = 0; loop < MEM_CGROUP_MAX_RECLAIM_LOOPS; loop++) { |
1862 | if (loop) |
1863 | drain_all_stock_async(memcg); |
1864 | total += try_to_free_mem_cgroup_pages(memcg, gfp_mask, noswap); |
1865 | /* |
1866 | * Allow limit shrinkers, which are triggered directly |
1867 | * by userspace, to catch signals and stop reclaim |
1868 | * after minimal progress, regardless of the margin. |
1869 | */ |
1870 | if (total && (flags & MEM_CGROUP_RECLAIM_SHRINK)) |
1871 | break; |
1872 | if (mem_cgroup_margin(memcg)) |
1873 | break; |
1874 | /* |
1875 | * If nothing was reclaimed after two attempts, there |
1876 | * may be no reclaimable pages in this hierarchy. |
1877 | */ |
1878 | if (loop && !total) |
1879 | break; |
1880 | } |
1881 | return total; |
1882 | } |
1883 | |
1884 | /** |
1885 | * test_mem_cgroup_node_reclaimable |
1886 | * @memcg: the target memcg |
1887 | * @nid: the node ID to be checked. |
1888 | * @noswap : specify true here if the user wants flle only information. |
1889 | * |
1890 | * This function returns whether the specified memcg contains any |
1891 | * reclaimable pages on a node. Returns true if there are any reclaimable |
1892 | * pages in the node. |
1893 | */ |
1894 | static bool test_mem_cgroup_node_reclaimable(struct mem_cgroup *memcg, |
1895 | int nid, bool noswap) |
1896 | { |
1897 | if (mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL_FILE)) |
1898 | return true; |
1899 | if (noswap || !total_swap_pages) |
1900 | return false; |
1901 | if (mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL_ANON)) |
1902 | return true; |
1903 | return false; |
1904 | |
1905 | } |
1906 | #if MAX_NUMNODES > 1 |
1907 | |
1908 | /* |
1909 | * Always updating the nodemask is not very good - even if we have an empty |
1910 | * list or the wrong list here, we can start from some node and traverse all |
1911 | * nodes based on the zonelist. So update the list loosely once per 10 secs. |
1912 | * |
1913 | */ |
1914 | static void mem_cgroup_may_update_nodemask(struct mem_cgroup *memcg) |
1915 | { |
1916 | int nid; |
1917 | /* |
1918 | * numainfo_events > 0 means there was at least NUMAINFO_EVENTS_TARGET |
1919 | * pagein/pageout changes since the last update. |
1920 | */ |
1921 | if (!atomic_read(&memcg->numainfo_events)) |
1922 | return; |
1923 | if (atomic_inc_return(&memcg->numainfo_updating) > 1) |
1924 | return; |
1925 | |
1926 | /* make a nodemask where this memcg uses memory from */ |
1927 | memcg->scan_nodes = node_states[N_MEMORY]; |
1928 | |
1929 | for_each_node_mask(nid, node_states[N_MEMORY]) { |
1930 | |
1931 | if (!test_mem_cgroup_node_reclaimable(memcg, nid, false)) |
1932 | node_clear(nid, memcg->scan_nodes); |
1933 | } |
1934 | |
1935 | atomic_set(&memcg->numainfo_events, 0); |
1936 | atomic_set(&memcg->numainfo_updating, 0); |
1937 | } |
1938 | |
1939 | /* |
1940 | * Selecting a node where we start reclaim from. Because what we need is just |
1941 | * reducing usage counter, start from anywhere is O,K. Considering |
1942 | * memory reclaim from current node, there are pros. and cons. |
1943 | * |
1944 | * Freeing memory from current node means freeing memory from a node which |
1945 | * we'll use or we've used. So, it may make LRU bad. And if several threads |
1946 | * hit limits, it will see a contention on a node. But freeing from remote |
1947 | * node means more costs for memory reclaim because of memory latency. |
1948 | * |
1949 | * Now, we use round-robin. Better algorithm is welcomed. |
1950 | */ |
1951 | int mem_cgroup_select_victim_node(struct mem_cgroup *memcg) |
1952 | { |
1953 | int node; |
1954 | |
1955 | mem_cgroup_may_update_nodemask(memcg); |
1956 | node = memcg->last_scanned_node; |
1957 | |
1958 | node = next_node(node, memcg->scan_nodes); |
1959 | if (node == MAX_NUMNODES) |
1960 | node = first_node(memcg->scan_nodes); |
1961 | /* |
1962 | * We call this when we hit limit, not when pages are added to LRU. |
1963 | * No LRU may hold pages because all pages are UNEVICTABLE or |
1964 | * memcg is too small and all pages are not on LRU. In that case, |
1965 | * we use curret node. |
1966 | */ |
1967 | if (unlikely(node == MAX_NUMNODES)) |
1968 | node = numa_node_id(); |
1969 | |
1970 | memcg->last_scanned_node = node; |
1971 | return node; |
1972 | } |
1973 | |
1974 | /* |
1975 | * Check all nodes whether it contains reclaimable pages or not. |
1976 | * For quick scan, we make use of scan_nodes. This will allow us to skip |
1977 | * unused nodes. But scan_nodes is lazily updated and may not cotain |
1978 | * enough new information. We need to do double check. |
1979 | */ |
1980 | static bool mem_cgroup_reclaimable(struct mem_cgroup *memcg, bool noswap) |
1981 | { |
1982 | int nid; |
1983 | |
1984 | /* |
1985 | * quick check...making use of scan_node. |
1986 | * We can skip unused nodes. |
1987 | */ |
1988 | if (!nodes_empty(memcg->scan_nodes)) { |
1989 | for (nid = first_node(memcg->scan_nodes); |
1990 | nid < MAX_NUMNODES; |
1991 | nid = next_node(nid, memcg->scan_nodes)) { |
1992 | |
1993 | if (test_mem_cgroup_node_reclaimable(memcg, nid, noswap)) |
1994 | return true; |
1995 | } |
1996 | } |
1997 | /* |
1998 | * Check rest of nodes. |
1999 | */ |
2000 | for_each_node_state(nid, N_MEMORY) { |
2001 | if (node_isset(nid, memcg->scan_nodes)) |
2002 | continue; |
2003 | if (test_mem_cgroup_node_reclaimable(memcg, nid, noswap)) |
2004 | return true; |
2005 | } |
2006 | return false; |
2007 | } |
2008 | |
2009 | #else |
2010 | int mem_cgroup_select_victim_node(struct mem_cgroup *memcg) |
2011 | { |
2012 | return 0; |
2013 | } |
2014 | |
2015 | static bool mem_cgroup_reclaimable(struct mem_cgroup *memcg, bool noswap) |
2016 | { |
2017 | return test_mem_cgroup_node_reclaimable(memcg, 0, noswap); |
2018 | } |
2019 | #endif |
2020 | |
2021 | static int mem_cgroup_soft_reclaim(struct mem_cgroup *root_memcg, |
2022 | struct zone *zone, |
2023 | gfp_t gfp_mask, |
2024 | unsigned long *total_scanned) |
2025 | { |
2026 | struct mem_cgroup *victim = NULL; |
2027 | int total = 0; |
2028 | int loop = 0; |
2029 | unsigned long excess; |
2030 | unsigned long nr_scanned; |
2031 | struct mem_cgroup_reclaim_cookie reclaim = { |
2032 | .zone = zone, |
2033 | .priority = 0, |
2034 | }; |
2035 | |
2036 | excess = res_counter_soft_limit_excess(&root_memcg->res) >> PAGE_SHIFT; |
2037 | |
2038 | while (1) { |
2039 | victim = mem_cgroup_iter(root_memcg, victim, &reclaim); |
2040 | if (!victim) { |
2041 | loop++; |
2042 | if (loop >= 2) { |
2043 | /* |
2044 | * If we have not been able to reclaim |
2045 | * anything, it might because there are |
2046 | * no reclaimable pages under this hierarchy |
2047 | */ |
2048 | if (!total) |
2049 | break; |
2050 | /* |
2051 | * We want to do more targeted reclaim. |
2052 | * excess >> 2 is not to excessive so as to |
2053 | * reclaim too much, nor too less that we keep |
2054 | * coming back to reclaim from this cgroup |
2055 | */ |
2056 | if (total >= (excess >> 2) || |
2057 | (loop > MEM_CGROUP_MAX_RECLAIM_LOOPS)) |
2058 | break; |
2059 | } |
2060 | continue; |
2061 | } |
2062 | if (!mem_cgroup_reclaimable(victim, false)) |
2063 | continue; |
2064 | total += mem_cgroup_shrink_node_zone(victim, gfp_mask, false, |
2065 | zone, &nr_scanned); |
2066 | *total_scanned += nr_scanned; |
2067 | if (!res_counter_soft_limit_excess(&root_memcg->res)) |
2068 | break; |
2069 | } |
2070 | mem_cgroup_iter_break(root_memcg, victim); |
2071 | return total; |
2072 | } |
2073 | |
2074 | #ifdef CONFIG_LOCKDEP |
2075 | static struct lockdep_map memcg_oom_lock_dep_map = { |
2076 | .name = "memcg_oom_lock", |
2077 | }; |
2078 | #endif |
2079 | |
2080 | static DEFINE_SPINLOCK(memcg_oom_lock); |
2081 | |
2082 | /* |
2083 | * Check OOM-Killer is already running under our hierarchy. |
2084 | * If someone is running, return false. |
2085 | */ |
2086 | static bool mem_cgroup_oom_trylock(struct mem_cgroup *memcg) |
2087 | { |
2088 | struct mem_cgroup *iter, *failed = NULL; |
2089 | |
2090 | spin_lock(&memcg_oom_lock); |
2091 | |
2092 | for_each_mem_cgroup_tree(iter, memcg) { |
2093 | if (iter->oom_lock) { |
2094 | /* |
2095 | * this subtree of our hierarchy is already locked |
2096 | * so we cannot give a lock. |
2097 | */ |
2098 | failed = iter; |
2099 | mem_cgroup_iter_break(memcg, iter); |
2100 | break; |
2101 | } else |
2102 | iter->oom_lock = true; |
2103 | } |
2104 | |
2105 | if (failed) { |
2106 | /* |
2107 | * OK, we failed to lock the whole subtree so we have |
2108 | * to clean up what we set up to the failing subtree |
2109 | */ |
2110 | for_each_mem_cgroup_tree(iter, memcg) { |
2111 | if (iter == failed) { |
2112 | mem_cgroup_iter_break(memcg, iter); |
2113 | break; |
2114 | } |
2115 | iter->oom_lock = false; |
2116 | } |
2117 | } else |
2118 | mutex_acquire(&memcg_oom_lock_dep_map, 0, 1, _RET_IP_); |
2119 | |
2120 | spin_unlock(&memcg_oom_lock); |
2121 | |
2122 | return !failed; |
2123 | } |
2124 | |
2125 | static void mem_cgroup_oom_unlock(struct mem_cgroup *memcg) |
2126 | { |
2127 | struct mem_cgroup *iter; |
2128 | |
2129 | spin_lock(&memcg_oom_lock); |
2130 | mutex_release(&memcg_oom_lock_dep_map, 1, _RET_IP_); |
2131 | for_each_mem_cgroup_tree(iter, memcg) |
2132 | iter->oom_lock = false; |
2133 | spin_unlock(&memcg_oom_lock); |
2134 | } |
2135 | |
2136 | static void mem_cgroup_mark_under_oom(struct mem_cgroup *memcg) |
2137 | { |
2138 | struct mem_cgroup *iter; |
2139 | |
2140 | for_each_mem_cgroup_tree(iter, memcg) |
2141 | atomic_inc(&iter->under_oom); |
2142 | } |
2143 | |
2144 | static void mem_cgroup_unmark_under_oom(struct mem_cgroup *memcg) |
2145 | { |
2146 | struct mem_cgroup *iter; |
2147 | |
2148 | /* |
2149 | * When a new child is created while the hierarchy is under oom, |
2150 | * mem_cgroup_oom_lock() may not be called. We have to use |
2151 | * atomic_add_unless() here. |
2152 | */ |
2153 | for_each_mem_cgroup_tree(iter, memcg) |
2154 | atomic_add_unless(&iter->under_oom, -1, 0); |
2155 | } |
2156 | |
2157 | static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq); |
2158 | |
2159 | struct oom_wait_info { |
2160 | struct mem_cgroup *memcg; |
2161 | wait_queue_t wait; |
2162 | }; |
2163 | |
2164 | static int memcg_oom_wake_function(wait_queue_t *wait, |
2165 | unsigned mode, int sync, void *arg) |
2166 | { |
2167 | struct mem_cgroup *wake_memcg = (struct mem_cgroup *)arg; |
2168 | struct mem_cgroup *oom_wait_memcg; |
2169 | struct oom_wait_info *oom_wait_info; |
2170 | |
2171 | oom_wait_info = container_of(wait, struct oom_wait_info, wait); |
2172 | oom_wait_memcg = oom_wait_info->memcg; |
2173 | |
2174 | /* |
2175 | * Both of oom_wait_info->memcg and wake_memcg are stable under us. |
2176 | * Then we can use css_is_ancestor without taking care of RCU. |
2177 | */ |
2178 | if (!mem_cgroup_same_or_subtree(oom_wait_memcg, wake_memcg) |
2179 | && !mem_cgroup_same_or_subtree(wake_memcg, oom_wait_memcg)) |
2180 | return 0; |
2181 | return autoremove_wake_function(wait, mode, sync, arg); |
2182 | } |
2183 | |
2184 | static void memcg_wakeup_oom(struct mem_cgroup *memcg) |
2185 | { |
2186 | atomic_inc(&memcg->oom_wakeups); |
2187 | /* for filtering, pass "memcg" as argument. */ |
2188 | __wake_up(&memcg_oom_waitq, TASK_NORMAL, 0, memcg); |
2189 | } |
2190 | |
2191 | static void memcg_oom_recover(struct mem_cgroup *memcg) |
2192 | { |
2193 | if (memcg && atomic_read(&memcg->under_oom)) |
2194 | memcg_wakeup_oom(memcg); |
2195 | } |
2196 | |
2197 | static void mem_cgroup_oom(struct mem_cgroup *memcg, gfp_t mask, int order) |
2198 | { |
2199 | if (!current->memcg_oom.may_oom) |
2200 | return; |
2201 | /* |
2202 | * We are in the middle of the charge context here, so we |
2203 | * don't want to block when potentially sitting on a callstack |
2204 | * that holds all kinds of filesystem and mm locks. |
2205 | * |
2206 | * Also, the caller may handle a failed allocation gracefully |
2207 | * (like optional page cache readahead) and so an OOM killer |
2208 | * invocation might not even be necessary. |
2209 | * |
2210 | * That's why we don't do anything here except remember the |
2211 | * OOM context and then deal with it at the end of the page |
2212 | * fault when the stack is unwound, the locks are released, |
2213 | * and when we know whether the fault was overall successful. |
2214 | */ |
2215 | css_get(&memcg->css); |
2216 | current->memcg_oom.memcg = memcg; |
2217 | current->memcg_oom.gfp_mask = mask; |
2218 | current->memcg_oom.order = order; |
2219 | } |
2220 | |
2221 | /** |
2222 | * mem_cgroup_oom_synchronize - complete memcg OOM handling |
2223 | * @handle: actually kill/wait or just clean up the OOM state |
2224 | * |
2225 | * This has to be called at the end of a page fault if the memcg OOM |
2226 | * handler was enabled. |
2227 | * |
2228 | * Memcg supports userspace OOM handling where failed allocations must |
2229 | * sleep on a waitqueue until the userspace task resolves the |
2230 | * situation. Sleeping directly in the charge context with all kinds |
2231 | * of locks held is not a good idea, instead we remember an OOM state |
2232 | * in the task and mem_cgroup_oom_synchronize() has to be called at |
2233 | * the end of the page fault to complete the OOM handling. |
2234 | * |
2235 | * Returns %true if an ongoing memcg OOM situation was detected and |
2236 | * completed, %false otherwise. |
2237 | */ |
2238 | bool mem_cgroup_oom_synchronize(bool handle) |
2239 | { |
2240 | struct mem_cgroup *memcg = current->memcg_oom.memcg; |
2241 | struct oom_wait_info owait; |
2242 | bool locked; |
2243 | |
2244 | /* OOM is global, do not handle */ |
2245 | if (!memcg) |
2246 | return false; |
2247 | |
2248 | if (!handle) |
2249 | goto cleanup; |
2250 | |
2251 | owait.memcg = memcg; |
2252 | owait.wait.flags = 0; |
2253 | owait.wait.func = memcg_oom_wake_function; |
2254 | owait.wait.private = current; |
2255 | INIT_LIST_HEAD(&owait.wait.task_list); |
2256 | |
2257 | prepare_to_wait(&memcg_oom_waitq, &owait.wait, TASK_KILLABLE); |
2258 | mem_cgroup_mark_under_oom(memcg); |
2259 | |
2260 | locked = mem_cgroup_oom_trylock(memcg); |
2261 | |
2262 | if (locked) |
2263 | mem_cgroup_oom_notify(memcg); |
2264 | |
2265 | if (locked && !memcg->oom_kill_disable) { |
2266 | mem_cgroup_unmark_under_oom(memcg); |
2267 | finish_wait(&memcg_oom_waitq, &owait.wait); |
2268 | mem_cgroup_out_of_memory(memcg, current->memcg_oom.gfp_mask, |
2269 | current->memcg_oom.order); |
2270 | } else { |
2271 | schedule(); |
2272 | mem_cgroup_unmark_under_oom(memcg); |
2273 | finish_wait(&memcg_oom_waitq, &owait.wait); |
2274 | } |
2275 | |
2276 | if (locked) { |
2277 | mem_cgroup_oom_unlock(memcg); |
2278 | /* |
2279 | * There is no guarantee that an OOM-lock contender |
2280 | * sees the wakeups triggered by the OOM kill |
2281 | * uncharges. Wake any sleepers explicitely. |
2282 | */ |
2283 | memcg_oom_recover(memcg); |
2284 | } |
2285 | cleanup: |
2286 | current->memcg_oom.memcg = NULL; |
2287 | css_put(&memcg->css); |
2288 | return true; |
2289 | } |
2290 | |
2291 | /* |
2292 | * Currently used to update mapped file statistics, but the routine can be |
2293 | * generalized to update other statistics as well. |
2294 | * |
2295 | * Notes: Race condition |
2296 | * |
2297 | * We usually use page_cgroup_lock() for accessing page_cgroup member but |
2298 | * it tends to be costly. But considering some conditions, we doesn't need |
2299 | * to do so _always_. |
2300 | * |
2301 | * Considering "charge", lock_page_cgroup() is not required because all |
2302 | * file-stat operations happen after a page is attached to radix-tree. There |
2303 | * are no race with "charge". |
2304 | * |
2305 | * Considering "uncharge", we know that memcg doesn't clear pc->mem_cgroup |
2306 | * at "uncharge" intentionally. So, we always see valid pc->mem_cgroup even |
2307 | * if there are race with "uncharge". Statistics itself is properly handled |
2308 | * by flags. |
2309 | * |
2310 | * Considering "move", this is an only case we see a race. To make the race |
2311 | * small, we check mm->moving_account and detect there are possibility of race |
2312 | * If there is, we take a lock. |
2313 | */ |
2314 | |
2315 | void __mem_cgroup_begin_update_page_stat(struct page *page, |
2316 | bool *locked, unsigned long *flags) |
2317 | { |
2318 | struct mem_cgroup *memcg; |
2319 | struct page_cgroup *pc; |
2320 | |
2321 | pc = lookup_page_cgroup(page); |
2322 | again: |
2323 | memcg = pc->mem_cgroup; |
2324 | if (unlikely(!memcg || !PageCgroupUsed(pc))) |
2325 | return; |
2326 | /* |
2327 | * If this memory cgroup is not under account moving, we don't |
2328 | * need to take move_lock_mem_cgroup(). Because we already hold |
2329 | * rcu_read_lock(), any calls to move_account will be delayed until |
2330 | * rcu_read_unlock() if mem_cgroup_stolen() == true. |
2331 | */ |
2332 | if (!mem_cgroup_stolen(memcg)) |
2333 | return; |
2334 | |
2335 | move_lock_mem_cgroup(memcg, flags); |
2336 | if (memcg != pc->mem_cgroup || !PageCgroupUsed(pc)) { |
2337 | move_unlock_mem_cgroup(memcg, flags); |
2338 | goto again; |
2339 | } |
2340 | *locked = true; |
2341 | } |
2342 | |
2343 | void __mem_cgroup_end_update_page_stat(struct page *page, unsigned long *flags) |
2344 | { |
2345 | struct page_cgroup *pc = lookup_page_cgroup(page); |
2346 | |
2347 | /* |
2348 | * It's guaranteed that pc->mem_cgroup never changes while |
2349 | * lock is held because a routine modifies pc->mem_cgroup |
2350 | * should take move_lock_mem_cgroup(). |
2351 | */ |
2352 | move_unlock_mem_cgroup(pc->mem_cgroup, flags); |
2353 | } |
2354 | |
2355 | void mem_cgroup_update_page_stat(struct page *page, |
2356 | enum mem_cgroup_stat_index idx, int val) |
2357 | { |
2358 | struct mem_cgroup *memcg; |
2359 | struct page_cgroup *pc = lookup_page_cgroup(page); |
2360 | unsigned long uninitialized_var(flags); |
2361 | |
2362 | if (mem_cgroup_disabled()) |
2363 | return; |
2364 | |
2365 | VM_BUG_ON(!rcu_read_lock_held()); |
2366 | memcg = pc->mem_cgroup; |
2367 | if (unlikely(!memcg || !PageCgroupUsed(pc))) |
2368 | return; |
2369 | |
2370 | this_cpu_add(memcg->stat->count[idx], val); |
2371 | } |
2372 | |
2373 | /* |
2374 | * size of first charge trial. "32" comes from vmscan.c's magic value. |
2375 | * TODO: maybe necessary to use big numbers in big irons. |
2376 | */ |
2377 | #define CHARGE_BATCH 32U |
2378 | struct memcg_stock_pcp { |
2379 | struct mem_cgroup *cached; /* this never be root cgroup */ |
2380 | unsigned int nr_pages; |
2381 | struct work_struct work; |
2382 | unsigned long flags; |
2383 | #define FLUSHING_CACHED_CHARGE 0 |
2384 | }; |
2385 | static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock); |
2386 | static DEFINE_MUTEX(percpu_charge_mutex); |
2387 | |
2388 | /** |
2389 | * consume_stock: Try to consume stocked charge on this cpu. |
2390 | * @memcg: memcg to consume from. |
2391 | * @nr_pages: how many pages to charge. |
2392 | * |
2393 | * The charges will only happen if @memcg matches the current cpu's memcg |
2394 | * stock, and at least @nr_pages are available in that stock. Failure to |
2395 | * service an allocation will refill the stock. |
2396 | * |
2397 | * returns true if successful, false otherwise. |
2398 | */ |
2399 | static bool consume_stock(struct mem_cgroup *memcg, unsigned int nr_pages) |
2400 | { |
2401 | struct memcg_stock_pcp *stock; |
2402 | bool ret = true; |
2403 | |
2404 | if (nr_pages > CHARGE_BATCH) |
2405 | return false; |
2406 | |
2407 | stock = &get_cpu_var(memcg_stock); |
2408 | if (memcg == stock->cached && stock->nr_pages >= nr_pages) |
2409 | stock->nr_pages -= nr_pages; |
2410 | else /* need to call res_counter_charge */ |
2411 | ret = false; |
2412 | put_cpu_var(memcg_stock); |
2413 | return ret; |
2414 | } |
2415 | |
2416 | /* |
2417 | * Returns stocks cached in percpu to res_counter and reset cached information. |
2418 | */ |
2419 | static void drain_stock(struct memcg_stock_pcp *stock) |
2420 | { |
2421 | struct mem_cgroup *old = stock->cached; |
2422 | |
2423 | if (stock->nr_pages) { |
2424 | unsigned long bytes = stock->nr_pages * PAGE_SIZE; |
2425 | |
2426 | res_counter_uncharge(&old->res, bytes); |
2427 | if (do_swap_account) |
2428 | res_counter_uncharge(&old->memsw, bytes); |
2429 | stock->nr_pages = 0; |
2430 | } |
2431 | stock->cached = NULL; |
2432 | } |
2433 | |
2434 | /* |
2435 | * This must be called under preempt disabled or must be called by |
2436 | * a thread which is pinned to local cpu. |
2437 | */ |
2438 | static void drain_local_stock(struct work_struct *dummy) |
2439 | { |
2440 | struct memcg_stock_pcp *stock = &__get_cpu_var(memcg_stock); |
2441 | drain_stock(stock); |
2442 | clear_bit(FLUSHING_CACHED_CHARGE, &stock->flags); |
2443 | } |
2444 | |
2445 | static void __init memcg_stock_init(void) |
2446 | { |
2447 | int cpu; |
2448 | |
2449 | for_each_possible_cpu(cpu) { |
2450 | struct memcg_stock_pcp *stock = |
2451 | &per_cpu(memcg_stock, cpu); |
2452 | INIT_WORK(&stock->work, drain_local_stock); |
2453 | } |
2454 | } |
2455 | |
2456 | /* |
2457 | * Cache charges(val) which is from res_counter, to local per_cpu area. |
2458 | * This will be consumed by consume_stock() function, later. |
2459 | */ |
2460 | static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages) |
2461 | { |
2462 | struct memcg_stock_pcp *stock = &get_cpu_var(memcg_stock); |
2463 | |
2464 | if (stock->cached != memcg) { /* reset if necessary */ |
2465 | drain_stock(stock); |
2466 | stock->cached = memcg; |
2467 | } |
2468 | stock->nr_pages += nr_pages; |
2469 | put_cpu_var(memcg_stock); |
2470 | } |
2471 | |
2472 | /* |
2473 | * Drains all per-CPU charge caches for given root_memcg resp. subtree |
2474 | * of the hierarchy under it. sync flag says whether we should block |
2475 | * until the work is done. |
2476 | */ |
2477 | static void drain_all_stock(struct mem_cgroup *root_memcg, bool sync) |
2478 | { |
2479 | int cpu, curcpu; |
2480 | |
2481 | /* Notify other cpus that system-wide "drain" is running */ |
2482 | get_online_cpus(); |
2483 | curcpu = get_cpu(); |
2484 | for_each_online_cpu(cpu) { |
2485 | struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu); |
2486 | struct mem_cgroup *memcg; |
2487 | |
2488 | memcg = stock->cached; |
2489 | if (!memcg || !stock->nr_pages) |
2490 | continue; |
2491 | if (!mem_cgroup_same_or_subtree(root_memcg, memcg)) |
2492 | continue; |
2493 | if (!test_and_set_bit(FLUSHING_CACHED_CHARGE, &stock->flags)) { |
2494 | if (cpu == curcpu) |
2495 | drain_local_stock(&stock->work); |
2496 | else |
2497 | schedule_work_on(cpu, &stock->work); |
2498 | } |
2499 | } |
2500 | put_cpu(); |
2501 | |
2502 | if (!sync) |
2503 | goto out; |
2504 | |
2505 | for_each_online_cpu(cpu) { |
2506 | struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu); |
2507 | if (test_bit(FLUSHING_CACHED_CHARGE, &stock->flags)) |
2508 | flush_work(&stock->work); |
2509 | } |
2510 | out: |
2511 | put_online_cpus(); |
2512 | } |
2513 | |
2514 | /* |
2515 | * Tries to drain stocked charges in other cpus. This function is asynchronous |
2516 | * and just put a work per cpu for draining localy on each cpu. Caller can |
2517 | * expects some charges will be back to res_counter later but cannot wait for |
2518 | * it. |
2519 | */ |
2520 | static void drain_all_stock_async(struct mem_cgroup *root_memcg) |
2521 | { |
2522 | /* |
2523 | * If someone calls draining, avoid adding more kworker runs. |
2524 | */ |
2525 | if (!mutex_trylock(&percpu_charge_mutex)) |
2526 | return; |
2527 | drain_all_stock(root_memcg, false); |
2528 | mutex_unlock(&percpu_charge_mutex); |
2529 | } |
2530 | |
2531 | /* This is a synchronous drain interface. */ |
2532 | static void drain_all_stock_sync(struct mem_cgroup *root_memcg) |
2533 | { |
2534 | /* called when force_empty is called */ |
2535 | mutex_lock(&percpu_charge_mutex); |
2536 | drain_all_stock(root_memcg, true); |
2537 | mutex_unlock(&percpu_charge_mutex); |
2538 | } |
2539 | |
2540 | /* |
2541 | * This function drains percpu counter value from DEAD cpu and |
2542 | * move it to local cpu. Note that this function can be preempted. |
2543 | */ |
2544 | static void mem_cgroup_drain_pcp_counter(struct mem_cgroup *memcg, int cpu) |
2545 | { |
2546 | int i; |
2547 | |
2548 | spin_lock(&memcg->pcp_counter_lock); |
2549 | for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) { |
2550 | long x = per_cpu(memcg->stat->count[i], cpu); |
2551 | |
2552 | per_cpu(memcg->stat->count[i], cpu) = 0; |
2553 | memcg->nocpu_base.count[i] += x; |
2554 | } |
2555 | for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++) { |
2556 | unsigned long x = per_cpu(memcg->stat->events[i], cpu); |
2557 | |
2558 | per_cpu(memcg->stat->events[i], cpu) = 0; |
2559 | memcg->nocpu_base.events[i] += x; |
2560 | } |
2561 | spin_unlock(&memcg->pcp_counter_lock); |
2562 | } |
2563 | |
2564 | static int memcg_cpu_hotplug_callback(struct notifier_block *nb, |
2565 | unsigned long action, |
2566 | void *hcpu) |
2567 | { |
2568 | int cpu = (unsigned long)hcpu; |
2569 | struct memcg_stock_pcp *stock; |
2570 | struct mem_cgroup *iter; |
2571 | |
2572 | if (action == CPU_ONLINE) |
2573 | return NOTIFY_OK; |
2574 | |
2575 | if (action != CPU_DEAD && action != CPU_DEAD_FROZEN) |
2576 | return NOTIFY_OK; |
2577 | |
2578 | for_each_mem_cgroup(iter) |
2579 | mem_cgroup_drain_pcp_counter(iter, cpu); |
2580 | |
2581 | stock = &per_cpu(memcg_stock, cpu); |
2582 | drain_stock(stock); |
2583 | return NOTIFY_OK; |
2584 | } |
2585 | |
2586 | |
2587 | /* See mem_cgroup_try_charge() for details */ |
2588 | enum { |
2589 | CHARGE_OK, /* success */ |
2590 | CHARGE_RETRY, /* need to retry but retry is not bad */ |
2591 | CHARGE_NOMEM, /* we can't do more. return -ENOMEM */ |
2592 | CHARGE_WOULDBLOCK, /* GFP_WAIT wasn't set and no enough res. */ |
2593 | }; |
2594 | |
2595 | static int mem_cgroup_do_charge(struct mem_cgroup *memcg, gfp_t gfp_mask, |
2596 | unsigned int nr_pages, unsigned int min_pages, |
2597 | bool invoke_oom) |
2598 | { |
2599 | unsigned long csize = nr_pages * PAGE_SIZE; |
2600 | struct mem_cgroup *mem_over_limit; |
2601 | struct res_counter *fail_res; |
2602 | unsigned long flags = 0; |
2603 | int ret; |
2604 | |
2605 | ret = res_counter_charge(&memcg->res, csize, &fail_res); |
2606 | |
2607 | if (likely(!ret)) { |
2608 | if (!do_swap_account) |
2609 | return CHARGE_OK; |
2610 | ret = res_counter_charge(&memcg->memsw, csize, &fail_res); |
2611 | if (likely(!ret)) |
2612 | return CHARGE_OK; |
2613 | |
2614 | res_counter_uncharge(&memcg->res, csize); |
2615 | mem_over_limit = mem_cgroup_from_res_counter(fail_res, memsw); |
2616 | flags |= MEM_CGROUP_RECLAIM_NOSWAP; |
2617 | } else |
2618 | mem_over_limit = mem_cgroup_from_res_counter(fail_res, res); |
2619 | /* |
2620 | * Never reclaim on behalf of optional batching, retry with a |
2621 | * single page instead. |
2622 | */ |
2623 | if (nr_pages > min_pages) |
2624 | return CHARGE_RETRY; |
2625 | |
2626 | if (!(gfp_mask & __GFP_WAIT)) |
2627 | return CHARGE_WOULDBLOCK; |
2628 | |
2629 | if (gfp_mask & __GFP_NORETRY) |
2630 | return CHARGE_NOMEM; |
2631 | |
2632 | ret = mem_cgroup_reclaim(mem_over_limit, gfp_mask, flags); |
2633 | if (mem_cgroup_margin(mem_over_limit) >= nr_pages) |
2634 | return CHARGE_RETRY; |
2635 | /* |
2636 | * Even though the limit is exceeded at this point, reclaim |
2637 | * may have been able to free some pages. Retry the charge |
2638 | * before killing the task. |
2639 | * |
2640 | * Only for regular pages, though: huge pages are rather |
2641 | * unlikely to succeed so close to the limit, and we fall back |
2642 | * to regular pages anyway in case of failure. |
2643 | */ |
2644 | if (nr_pages <= (1 << PAGE_ALLOC_COSTLY_ORDER) && ret) |
2645 | return CHARGE_RETRY; |
2646 | |
2647 | /* |
2648 | * At task move, charge accounts can be doubly counted. So, it's |
2649 | * better to wait until the end of task_move if something is going on. |
2650 | */ |
2651 | if (mem_cgroup_wait_acct_move(mem_over_limit)) |
2652 | return CHARGE_RETRY; |
2653 | |
2654 | if (invoke_oom) |
2655 | mem_cgroup_oom(mem_over_limit, gfp_mask, get_order(csize)); |
2656 | |
2657 | return CHARGE_NOMEM; |
2658 | } |
2659 | |
2660 | /** |
2661 | * mem_cgroup_try_charge - try charging a memcg |
2662 | * @memcg: memcg to charge |
2663 | * @nr_pages: number of pages to charge |
2664 | * @oom: trigger OOM if reclaim fails |
2665 | * |
2666 | * Returns 0 if @memcg was charged successfully, -EINTR if the charge |
2667 | * was bypassed to root_mem_cgroup, and -ENOMEM if the charge failed. |
2668 | */ |
2669 | static int mem_cgroup_try_charge(struct mem_cgroup *memcg, |
2670 | gfp_t gfp_mask, |
2671 | unsigned int nr_pages, |
2672 | bool oom) |
2673 | { |
2674 | unsigned int batch = max(CHARGE_BATCH, nr_pages); |
2675 | int nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES; |
2676 | int ret; |
2677 | |
2678 | if (mem_cgroup_is_root(memcg)) |
2679 | goto done; |
2680 | /* |
2681 | * Unlike in global OOM situations, memcg is not in a physical |
2682 | * memory shortage. Allow dying and OOM-killed tasks to |
2683 | * bypass the last charges so that they can exit quickly and |
2684 | * free their memory. |
2685 | */ |
2686 | if (unlikely(test_thread_flag(TIF_MEMDIE) || |
2687 | fatal_signal_pending(current))) |
2688 | goto bypass; |
2689 | |
2690 | if (unlikely(task_in_memcg_oom(current))) |
2691 | goto nomem; |
2692 | |
2693 | if (gfp_mask & __GFP_NOFAIL) |
2694 | oom = false; |
2695 | again: |
2696 | if (consume_stock(memcg, nr_pages)) |
2697 | goto done; |
2698 | |
2699 | do { |
2700 | bool invoke_oom = oom && !nr_oom_retries; |
2701 | |
2702 | /* If killed, bypass charge */ |
2703 | if (fatal_signal_pending(current)) |
2704 | goto bypass; |
2705 | |
2706 | ret = mem_cgroup_do_charge(memcg, gfp_mask, batch, |
2707 | nr_pages, invoke_oom); |
2708 | switch (ret) { |
2709 | case CHARGE_OK: |
2710 | break; |
2711 | case CHARGE_RETRY: /* not in OOM situation but retry */ |
2712 | batch = nr_pages; |
2713 | goto again; |
2714 | case CHARGE_WOULDBLOCK: /* !__GFP_WAIT */ |
2715 | goto nomem; |
2716 | case CHARGE_NOMEM: /* OOM routine works */ |
2717 | if (!oom || invoke_oom) |
2718 | goto nomem; |
2719 | nr_oom_retries--; |
2720 | break; |
2721 | } |
2722 | } while (ret != CHARGE_OK); |
2723 | |
2724 | if (batch > nr_pages) |
2725 | refill_stock(memcg, batch - nr_pages); |
2726 | done: |
2727 | return 0; |
2728 | nomem: |
2729 | if (!(gfp_mask & __GFP_NOFAIL)) |
2730 | return -ENOMEM; |
2731 | bypass: |
2732 | return -EINTR; |
2733 | } |
2734 | |
2735 | /** |
2736 | * mem_cgroup_try_charge_mm - try charging a mm |
2737 | * @mm: mm_struct to charge |
2738 | * @nr_pages: number of pages to charge |
2739 | * @oom: trigger OOM if reclaim fails |
2740 | * |
2741 | * Returns the charged mem_cgroup associated with the given mm_struct or |
2742 | * NULL the charge failed. |
2743 | */ |
2744 | static struct mem_cgroup *mem_cgroup_try_charge_mm(struct mm_struct *mm, |
2745 | gfp_t gfp_mask, |
2746 | unsigned int nr_pages, |
2747 | bool oom) |
2748 | |
2749 | { |
2750 | struct mem_cgroup *memcg; |
2751 | int ret; |
2752 | |
2753 | memcg = get_mem_cgroup_from_mm(mm); |
2754 | ret = mem_cgroup_try_charge(memcg, gfp_mask, nr_pages, oom); |
2755 | css_put(&memcg->css); |
2756 | if (ret == -EINTR) |
2757 | memcg = root_mem_cgroup; |
2758 | else if (ret) |
2759 | memcg = NULL; |
2760 | |
2761 | return memcg; |
2762 | } |
2763 | |
2764 | /* |
2765 | * Somemtimes we have to undo a charge we got by try_charge(). |
2766 | * This function is for that and do uncharge, put css's refcnt. |
2767 | * gotten by try_charge(). |
2768 | */ |
2769 | static void __mem_cgroup_cancel_charge(struct mem_cgroup *memcg, |
2770 | unsigned int nr_pages) |
2771 | { |
2772 | if (!mem_cgroup_is_root(memcg)) { |
2773 | unsigned long bytes = nr_pages * PAGE_SIZE; |
2774 | |
2775 | res_counter_uncharge(&memcg->res, bytes); |
2776 | if (do_swap_account) |
2777 | res_counter_uncharge(&memcg->memsw, bytes); |
2778 | } |
2779 | } |
2780 | |
2781 | /* |
2782 | * Cancel chrages in this cgroup....doesn't propagate to parent cgroup. |
2783 | * This is useful when moving usage to parent cgroup. |
2784 | */ |
2785 | static void __mem_cgroup_cancel_local_charge(struct mem_cgroup *memcg, |
2786 | unsigned int nr_pages) |
2787 | { |
2788 | unsigned long bytes = nr_pages * PAGE_SIZE; |
2789 | |
2790 | if (mem_cgroup_is_root(memcg)) |
2791 | return; |
2792 | |
2793 | res_counter_uncharge_until(&memcg->res, memcg->res.parent, bytes); |
2794 | if (do_swap_account) |
2795 | res_counter_uncharge_until(&memcg->memsw, |
2796 | memcg->memsw.parent, bytes); |
2797 | } |
2798 | |
2799 | /* |
2800 | * A helper function to get mem_cgroup from ID. must be called under |
2801 | * rcu_read_lock(). The caller is responsible for calling css_tryget if |
2802 | * the mem_cgroup is used for charging. (dropping refcnt from swap can be |
2803 | * called against removed memcg.) |
2804 | */ |
2805 | static struct mem_cgroup *mem_cgroup_lookup(unsigned short id) |
2806 | { |
2807 | /* ID 0 is unused ID */ |
2808 | if (!id) |
2809 | return NULL; |
2810 | return mem_cgroup_from_id(id); |
2811 | } |
2812 | |
2813 | struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page) |
2814 | { |
2815 | struct mem_cgroup *memcg = NULL; |
2816 | struct page_cgroup *pc; |
2817 | unsigned short id; |
2818 | swp_entry_t ent; |
2819 | |
2820 | VM_BUG_ON_PAGE(!PageLocked(page), page); |
2821 | |
2822 | pc = lookup_page_cgroup(page); |
2823 | lock_page_cgroup(pc); |
2824 | if (PageCgroupUsed(pc)) { |
2825 | memcg = pc->mem_cgroup; |
2826 | if (memcg && !css_tryget(&memcg->css)) |
2827 | memcg = NULL; |
2828 | } else if (PageSwapCache(page)) { |
2829 | ent.val = page_private(page); |
2830 | id = lookup_swap_cgroup_id(ent); |
2831 | rcu_read_lock(); |
2832 | memcg = mem_cgroup_lookup(id); |
2833 | if (memcg && !css_tryget(&memcg->css)) |
2834 | memcg = NULL; |
2835 | rcu_read_unlock(); |
2836 | } |
2837 | unlock_page_cgroup(pc); |
2838 | return memcg; |
2839 | } |
2840 | |
2841 | static void __mem_cgroup_commit_charge(struct mem_cgroup *memcg, |
2842 | struct page *page, |
2843 | unsigned int nr_pages, |
2844 | enum charge_type ctype, |
2845 | bool lrucare) |
2846 | { |
2847 | struct page_cgroup *pc = lookup_page_cgroup(page); |
2848 | struct zone *uninitialized_var(zone); |
2849 | struct lruvec *lruvec; |
2850 | bool was_on_lru = false; |
2851 | bool anon; |
2852 | |
2853 | lock_page_cgroup(pc); |
2854 | VM_BUG_ON_PAGE(PageCgroupUsed(pc), page); |
2855 | /* |
2856 | * we don't need page_cgroup_lock about tail pages, becase they are not |
2857 | * accessed by any other context at this point. |
2858 | */ |
2859 | |
2860 | /* |
2861 | * In some cases, SwapCache and FUSE(splice_buf->radixtree), the page |
2862 | * may already be on some other mem_cgroup's LRU. Take care of it. |
2863 | */ |
2864 | if (lrucare) { |
2865 | zone = page_zone(page); |
2866 | spin_lock_irq(&zone->lru_lock); |
2867 | if (PageLRU(page)) { |
2868 | lruvec = mem_cgroup_zone_lruvec(zone, pc->mem_cgroup); |
2869 | ClearPageLRU(page); |
2870 | del_page_from_lru_list(page, lruvec, page_lru(page)); |
2871 | was_on_lru = true; |
2872 | } |
2873 | } |
2874 | |
2875 | pc->mem_cgroup = memcg; |
2876 | /* |
2877 | * We access a page_cgroup asynchronously without lock_page_cgroup(). |
2878 | * Especially when a page_cgroup is taken from a page, pc->mem_cgroup |
2879 | * is accessed after testing USED bit. To make pc->mem_cgroup visible |
2880 | * before USED bit, we need memory barrier here. |
2881 | * See mem_cgroup_add_lru_list(), etc. |
2882 | */ |
2883 | smp_wmb(); |
2884 | SetPageCgroupUsed(pc); |
2885 | |
2886 | if (lrucare) { |
2887 | if (was_on_lru) { |
2888 | lruvec = mem_cgroup_zone_lruvec(zone, pc->mem_cgroup); |
2889 | VM_BUG_ON_PAGE(PageLRU(page), page); |
2890 | SetPageLRU(page); |
2891 | add_page_to_lru_list(page, lruvec, page_lru(page)); |
2892 | } |
2893 | spin_unlock_irq(&zone->lru_lock); |
2894 | } |
2895 | |
2896 | if (ctype == MEM_CGROUP_CHARGE_TYPE_ANON) |
2897 | anon = true; |
2898 | else |
2899 | anon = false; |
2900 | |
2901 | mem_cgroup_charge_statistics(memcg, page, anon, nr_pages); |
2902 | unlock_page_cgroup(pc); |
2903 | |
2904 | /* |
2905 | * "charge_statistics" updated event counter. Then, check it. |
2906 | * Insert ancestor (and ancestor's ancestors), to softlimit RB-tree. |
2907 | * if they exceeds softlimit. |
2908 | */ |
2909 | memcg_check_events(memcg, page); |
2910 | } |
2911 | |
2912 | static DEFINE_MUTEX(set_limit_mutex); |
2913 | |
2914 | #ifdef CONFIG_MEMCG_KMEM |
2915 | static DEFINE_MUTEX(activate_kmem_mutex); |
2916 | |
2917 | static inline bool memcg_can_account_kmem(struct mem_cgroup *memcg) |
2918 | { |
2919 | return !mem_cgroup_disabled() && !mem_cgroup_is_root(memcg) && |
2920 | memcg_kmem_is_active(memcg); |
2921 | } |
2922 | |
2923 | /* |
2924 | * This is a bit cumbersome, but it is rarely used and avoids a backpointer |
2925 | * in the memcg_cache_params struct. |
2926 | */ |
2927 | static struct kmem_cache *memcg_params_to_cache(struct memcg_cache_params *p) |
2928 | { |
2929 | struct kmem_cache *cachep; |
2930 | |
2931 | VM_BUG_ON(p->is_root_cache); |
2932 | cachep = p->root_cache; |
2933 | return cache_from_memcg_idx(cachep, memcg_cache_id(p->memcg)); |
2934 | } |
2935 | |
2936 | #ifdef CONFIG_SLABINFO |
2937 | static int mem_cgroup_slabinfo_read(struct seq_file *m, void *v) |
2938 | { |
2939 | struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m)); |
2940 | struct memcg_cache_params *params; |
2941 | |
2942 | if (!memcg_can_account_kmem(memcg)) |
2943 | return -EIO; |
2944 | |
2945 | print_slabinfo_header(m); |
2946 | |
2947 | mutex_lock(&memcg->slab_caches_mutex); |
2948 | list_for_each_entry(params, &memcg->memcg_slab_caches, list) |
2949 | cache_show(memcg_params_to_cache(params), m); |
2950 | mutex_unlock(&memcg->slab_caches_mutex); |
2951 | |
2952 | return 0; |
2953 | } |
2954 | #endif |
2955 | |
2956 | static int memcg_charge_kmem(struct mem_cgroup *memcg, gfp_t gfp, u64 size) |
2957 | { |
2958 | struct res_counter *fail_res; |
2959 | int ret = 0; |
2960 | |
2961 | ret = res_counter_charge(&memcg->kmem, size, &fail_res); |
2962 | if (ret) |
2963 | return ret; |
2964 | |
2965 | ret = mem_cgroup_try_charge(memcg, gfp, size >> PAGE_SHIFT, |
2966 | oom_gfp_allowed(gfp)); |
2967 | if (ret == -EINTR) { |
2968 | /* |
2969 | * mem_cgroup_try_charge() chosed to bypass to root due to |
2970 | * OOM kill or fatal signal. Since our only options are to |
2971 | * either fail the allocation or charge it to this cgroup, do |
2972 | * it as a temporary condition. But we can't fail. From a |
2973 | * kmem/slab perspective, the cache has already been selected, |
2974 | * by mem_cgroup_kmem_get_cache(), so it is too late to change |
2975 | * our minds. |
2976 | * |
2977 | * This condition will only trigger if the task entered |
2978 | * memcg_charge_kmem in a sane state, but was OOM-killed during |
2979 | * mem_cgroup_try_charge() above. Tasks that were already |
2980 | * dying when the allocation triggers should have been already |
2981 | * directed to the root cgroup in memcontrol.h |
2982 | */ |
2983 | res_counter_charge_nofail(&memcg->res, size, &fail_res); |
2984 | if (do_swap_account) |
2985 | res_counter_charge_nofail(&memcg->memsw, size, |
2986 | &fail_res); |
2987 | ret = 0; |
2988 | } else if (ret) |
2989 | res_counter_uncharge(&memcg->kmem, size); |
2990 | |
2991 | return ret; |
2992 | } |
2993 | |
2994 | static void memcg_uncharge_kmem(struct mem_cgroup *memcg, u64 size) |
2995 | { |
2996 | res_counter_uncharge(&memcg->res, size); |
2997 | if (do_swap_account) |
2998 | res_counter_uncharge(&memcg->memsw, size); |
2999 | |
3000 | /* Not down to 0 */ |
3001 | if (res_counter_uncharge(&memcg->kmem, size)) |
3002 | return; |
3003 | |
3004 | /* |
3005 | * Releases a reference taken in kmem_cgroup_css_offline in case |
3006 | * this last uncharge is racing with the offlining code or it is |
3007 | * outliving the memcg existence. |
3008 | * |
3009 | * The memory barrier imposed by test&clear is paired with the |
3010 | * explicit one in memcg_kmem_mark_dead(). |
3011 | */ |
3012 | if (memcg_kmem_test_and_clear_dead(memcg)) |
3013 | css_put(&memcg->css); |
3014 | } |
3015 | |
3016 | /* |
3017 | * helper for acessing a memcg's index. It will be used as an index in the |
3018 | * child cache array in kmem_cache, and also to derive its name. This function |
3019 | * will return -1 when this is not a kmem-limited memcg. |
3020 | */ |
3021 | int memcg_cache_id(struct mem_cgroup *memcg) |
3022 | { |
3023 | return memcg ? memcg->kmemcg_id : -1; |
3024 | } |
3025 | |
3026 | static size_t memcg_caches_array_size(int num_groups) |
3027 | { |
3028 | ssize_t size; |
3029 | if (num_groups <= 0) |
3030 | return 0; |
3031 | |
3032 | size = 2 * num_groups; |
3033 | if (size < MEMCG_CACHES_MIN_SIZE) |
3034 | size = MEMCG_CACHES_MIN_SIZE; |
3035 | else if (size > MEMCG_CACHES_MAX_SIZE) |
3036 | size = MEMCG_CACHES_MAX_SIZE; |
3037 | |
3038 | return size; |
3039 | } |
3040 | |
3041 | /* |
3042 | * We should update the current array size iff all caches updates succeed. This |
3043 | * can only be done from the slab side. The slab mutex needs to be held when |
3044 | * calling this. |
3045 | */ |
3046 | void memcg_update_array_size(int num) |
3047 | { |
3048 | if (num > memcg_limited_groups_array_size) |
3049 | memcg_limited_groups_array_size = memcg_caches_array_size(num); |
3050 | } |
3051 | |
3052 | static void kmem_cache_destroy_work_func(struct work_struct *w); |
3053 | |
3054 | int memcg_update_cache_size(struct kmem_cache *s, int num_groups) |
3055 | { |
3056 | struct memcg_cache_params *cur_params = s->memcg_params; |
3057 | |
3058 | VM_BUG_ON(!is_root_cache(s)); |
3059 | |
3060 | if (num_groups > memcg_limited_groups_array_size) { |
3061 | int i; |
3062 | struct memcg_cache_params *new_params; |
3063 | ssize_t size = memcg_caches_array_size(num_groups); |
3064 | |
3065 | size *= sizeof(void *); |
3066 | size += offsetof(struct memcg_cache_params, memcg_caches); |
3067 | |
3068 | new_params = kzalloc(size, GFP_KERNEL); |
3069 | if (!new_params) |
3070 | return -ENOMEM; |
3071 | |
3072 | new_params->is_root_cache = true; |
3073 | |
3074 | /* |
3075 | * There is the chance it will be bigger than |
3076 | * memcg_limited_groups_array_size, if we failed an allocation |
3077 | * in a cache, in which case all caches updated before it, will |
3078 | * have a bigger array. |
3079 | * |
3080 | * But if that is the case, the data after |
3081 | * memcg_limited_groups_array_size is certainly unused |
3082 | */ |
3083 | for (i = 0; i < memcg_limited_groups_array_size; i++) { |
3084 | if (!cur_params->memcg_caches[i]) |
3085 | continue; |
3086 | new_params->memcg_caches[i] = |
3087 | cur_params->memcg_caches[i]; |
3088 | } |
3089 | |
3090 | /* |
3091 | * Ideally, we would wait until all caches succeed, and only |
3092 | * then free the old one. But this is not worth the extra |
3093 | * pointer per-cache we'd have to have for this. |
3094 | * |
3095 | * It is not a big deal if some caches are left with a size |
3096 | * bigger than the others. And all updates will reset this |
3097 | * anyway. |
3098 | */ |
3099 | rcu_assign_pointer(s->memcg_params, new_params); |
3100 | if (cur_params) |
3101 | kfree_rcu(cur_params, rcu_head); |
3102 | } |
3103 | return 0; |
3104 | } |
3105 | |
3106 | char *memcg_create_cache_name(struct mem_cgroup *memcg, |
3107 | struct kmem_cache *root_cache) |
3108 | { |
3109 | static char *buf = NULL; |
3110 | |
3111 | /* |
3112 | * We need a mutex here to protect the shared buffer. Since this is |
3113 | * expected to be called only on cache creation, we can employ the |
3114 | * slab_mutex for that purpose. |
3115 | */ |
3116 | lockdep_assert_held(&slab_mutex); |
3117 | |
3118 | if (!buf) { |
3119 | buf = kmalloc(NAME_MAX + 1, GFP_KERNEL); |
3120 | if (!buf) |
3121 | return NULL; |
3122 | } |
3123 | |
3124 | cgroup_name(memcg->css.cgroup, buf, NAME_MAX + 1); |
3125 | return kasprintf(GFP_KERNEL, "%s(%d:%s)", root_cache->name, |
3126 | memcg_cache_id(memcg), buf); |
3127 | } |
3128 | |
3129 | int memcg_alloc_cache_params(struct mem_cgroup *memcg, struct kmem_cache *s, |
3130 | struct kmem_cache *root_cache) |
3131 | { |
3132 | size_t size; |
3133 | |
3134 | if (!memcg_kmem_enabled()) |
3135 | return 0; |
3136 | |
3137 | if (!memcg) { |
3138 | size = offsetof(struct memcg_cache_params, memcg_caches); |
3139 | size += memcg_limited_groups_array_size * sizeof(void *); |
3140 | } else |
3141 | size = sizeof(struct memcg_cache_params); |
3142 | |
3143 | s->memcg_params = kzalloc(size, GFP_KERNEL); |
3144 | if (!s->memcg_params) |
3145 | return -ENOMEM; |
3146 | |
3147 | if (memcg) { |
3148 | s->memcg_params->memcg = memcg; |
3149 | s->memcg_params->root_cache = root_cache; |
3150 | INIT_WORK(&s->memcg_params->destroy, |
3151 | kmem_cache_destroy_work_func); |
3152 | css_get(&memcg->css); |
3153 | } else |
3154 | s->memcg_params->is_root_cache = true; |
3155 | |
3156 | return 0; |
3157 | } |
3158 | |
3159 | void memcg_free_cache_params(struct kmem_cache *s) |
3160 | { |
3161 | if (!s->memcg_params) |
3162 | return; |
3163 | if (!s->memcg_params->is_root_cache) |
3164 | css_put(&s->memcg_params->memcg->css); |
3165 | kfree(s->memcg_params); |
3166 | } |
3167 | |
3168 | void memcg_register_cache(struct kmem_cache *s) |
3169 | { |
3170 | struct kmem_cache *root; |
3171 | struct mem_cgroup *memcg; |
3172 | int id; |
3173 | |
3174 | if (is_root_cache(s)) |
3175 | return; |
3176 | |
3177 | /* |
3178 | * Holding the slab_mutex assures nobody will touch the memcg_caches |
3179 | * array while we are modifying it. |
3180 | */ |
3181 | lockdep_assert_held(&slab_mutex); |
3182 | |
3183 | root = s->memcg_params->root_cache; |
3184 | memcg = s->memcg_params->memcg; |
3185 | id = memcg_cache_id(memcg); |
3186 | |
3187 | /* |
3188 | * Since readers won't lock (see cache_from_memcg_idx()), we need a |
3189 | * barrier here to ensure nobody will see the kmem_cache partially |
3190 | * initialized. |
3191 | */ |
3192 | smp_wmb(); |
3193 | |
3194 | /* |
3195 | * Initialize the pointer to this cache in its parent's memcg_params |
3196 | * before adding it to the memcg_slab_caches list, otherwise we can |
3197 | * fail to convert memcg_params_to_cache() while traversing the list. |
3198 | */ |
3199 | VM_BUG_ON(root->memcg_params->memcg_caches[id]); |
3200 | root->memcg_params->memcg_caches[id] = s; |
3201 | |
3202 | mutex_lock(&memcg->slab_caches_mutex); |
3203 | list_add(&s->memcg_params->list, &memcg->memcg_slab_caches); |
3204 | mutex_unlock(&memcg->slab_caches_mutex); |
3205 | } |
3206 | |
3207 | void memcg_unregister_cache(struct kmem_cache *s) |
3208 | { |
3209 | struct kmem_cache *root; |
3210 | struct mem_cgroup *memcg; |
3211 | int id; |
3212 | |
3213 | if (is_root_cache(s)) |
3214 | return; |
3215 | |
3216 | /* |
3217 | * Holding the slab_mutex assures nobody will touch the memcg_caches |
3218 | * array while we are modifying it. |
3219 | */ |
3220 | lockdep_assert_held(&slab_mutex); |
3221 | |
3222 | root = s->memcg_params->root_cache; |
3223 | memcg = s->memcg_params->memcg; |
3224 | id = memcg_cache_id(memcg); |
3225 | |
3226 | mutex_lock(&memcg->slab_caches_mutex); |
3227 | list_del(&s->memcg_params->list); |
3228 | mutex_unlock(&memcg->slab_caches_mutex); |
3229 | |
3230 | /* |
3231 | * Clear the pointer to this cache in its parent's memcg_params only |
3232 | * after removing it from the memcg_slab_caches list, otherwise we can |
3233 | * fail to convert memcg_params_to_cache() while traversing the list. |
3234 | */ |
3235 | VM_BUG_ON(root->memcg_params->memcg_caches[id] != s); |
3236 | root->memcg_params->memcg_caches[id] = NULL; |
3237 | } |
3238 | |
3239 | /* |
3240 | * During the creation a new cache, we need to disable our accounting mechanism |
3241 | * altogether. This is true even if we are not creating, but rather just |
3242 | * enqueing new caches to be created. |
3243 | * |
3244 | * This is because that process will trigger allocations; some visible, like |
3245 | * explicit kmallocs to auxiliary data structures, name strings and internal |
3246 | * cache structures; some well concealed, like INIT_WORK() that can allocate |
3247 | * objects during debug. |
3248 | * |
3249 | * If any allocation happens during memcg_kmem_get_cache, we will recurse back |
3250 | * to it. This may not be a bounded recursion: since the first cache creation |
3251 | * failed to complete (waiting on the allocation), we'll just try to create the |
3252 | * cache again, failing at the same point. |
3253 | * |
3254 | * memcg_kmem_get_cache is prepared to abort after seeing a positive count of |
3255 | * memcg_kmem_skip_account. So we enclose anything that might allocate memory |
3256 | * inside the following two functions. |
3257 | */ |
3258 | static inline void memcg_stop_kmem_account(void) |
3259 | { |
3260 | VM_BUG_ON(!current->mm); |
3261 | current->memcg_kmem_skip_account++; |
3262 | } |
3263 | |
3264 | static inline void memcg_resume_kmem_account(void) |
3265 | { |
3266 | VM_BUG_ON(!current->mm); |
3267 | current->memcg_kmem_skip_account--; |
3268 | } |
3269 | |
3270 | static void kmem_cache_destroy_work_func(struct work_struct *w) |
3271 | { |
3272 | struct kmem_cache *cachep; |
3273 | struct memcg_cache_params *p; |
3274 | |
3275 | p = container_of(w, struct memcg_cache_params, destroy); |
3276 | |
3277 | cachep = memcg_params_to_cache(p); |
3278 | |
3279 | /* |
3280 | * If we get down to 0 after shrink, we could delete right away. |
3281 | * However, memcg_release_pages() already puts us back in the workqueue |
3282 | * in that case. If we proceed deleting, we'll get a dangling |
3283 | * reference, and removing the object from the workqueue in that case |
3284 | * is unnecessary complication. We are not a fast path. |
3285 | * |
3286 | * Note that this case is fundamentally different from racing with |
3287 | * shrink_slab(): if memcg_cgroup_destroy_cache() is called in |
3288 | * kmem_cache_shrink, not only we would be reinserting a dead cache |
3289 | * into the queue, but doing so from inside the worker racing to |
3290 | * destroy it. |
3291 | * |
3292 | * So if we aren't down to zero, we'll just schedule a worker and try |
3293 | * again |
3294 | */ |
3295 | if (atomic_read(&cachep->memcg_params->nr_pages) != 0) |
3296 | kmem_cache_shrink(cachep); |
3297 | else |
3298 | kmem_cache_destroy(cachep); |
3299 | } |
3300 | |
3301 | void mem_cgroup_destroy_cache(struct kmem_cache *cachep) |
3302 | { |
3303 | if (!cachep->memcg_params->dead) |
3304 | return; |
3305 | |
3306 | /* |
3307 | * There are many ways in which we can get here. |
3308 | * |
3309 | * We can get to a memory-pressure situation while the delayed work is |
3310 | * still pending to run. The vmscan shrinkers can then release all |
3311 | * cache memory and get us to destruction. If this is the case, we'll |
3312 | * be executed twice, which is a bug (the second time will execute over |
3313 | * bogus data). In this case, cancelling the work should be fine. |
3314 | * |
3315 | * But we can also get here from the worker itself, if |
3316 | * kmem_cache_shrink is enough to shake all the remaining objects and |
3317 | * get the page count to 0. In this case, we'll deadlock if we try to |
3318 | * cancel the work (the worker runs with an internal lock held, which |
3319 | * is the same lock we would hold for cancel_work_sync().) |
3320 | * |
3321 | * Since we can't possibly know who got us here, just refrain from |
3322 | * running if there is already work pending |
3323 | */ |
3324 | if (work_pending(&cachep->memcg_params->destroy)) |
3325 | return; |
3326 | /* |
3327 | * We have to defer the actual destroying to a workqueue, because |
3328 | * we might currently be in a context that cannot sleep. |
3329 | */ |
3330 | schedule_work(&cachep->memcg_params->destroy); |
3331 | } |
3332 | |
3333 | int __kmem_cache_destroy_memcg_children(struct kmem_cache *s) |
3334 | { |
3335 | struct kmem_cache *c; |
3336 | int i, failed = 0; |
3337 | |
3338 | /* |
3339 | * If the cache is being destroyed, we trust that there is no one else |
3340 | * requesting objects from it. Even if there are, the sanity checks in |
3341 | * kmem_cache_destroy should caught this ill-case. |
3342 | * |
3343 | * Still, we don't want anyone else freeing memcg_caches under our |
3344 | * noses, which can happen if a new memcg comes to life. As usual, |
3345 | * we'll take the activate_kmem_mutex to protect ourselves against |
3346 | * this. |
3347 | */ |
3348 | mutex_lock(&activate_kmem_mutex); |
3349 | for_each_memcg_cache_index(i) { |
3350 | c = cache_from_memcg_idx(s, i); |
3351 | if (!c) |
3352 | continue; |
3353 | |
3354 | /* |
3355 | * We will now manually delete the caches, so to avoid races |
3356 | * we need to cancel all pending destruction workers and |
3357 | * proceed with destruction ourselves. |
3358 | * |
3359 | * kmem_cache_destroy() will call kmem_cache_shrink internally, |
3360 | * and that could spawn the workers again: it is likely that |
3361 | * the cache still have active pages until this very moment. |
3362 | * This would lead us back to mem_cgroup_destroy_cache. |
3363 | * |
3364 | * But that will not execute at all if the "dead" flag is not |
3365 | * set, so flip it down to guarantee we are in control. |
3366 | */ |
3367 | c->memcg_params->dead = false; |
3368 | cancel_work_sync(&c->memcg_params->destroy); |
3369 | kmem_cache_destroy(c); |
3370 | |
3371 | if (cache_from_memcg_idx(s, i)) |
3372 | failed++; |
3373 | } |
3374 | mutex_unlock(&activate_kmem_mutex); |
3375 | return failed; |
3376 | } |
3377 | |
3378 | static void mem_cgroup_destroy_all_caches(struct mem_cgroup *memcg) |
3379 | { |
3380 | struct kmem_cache *cachep; |
3381 | struct memcg_cache_params *params; |
3382 | |
3383 | if (!memcg_kmem_is_active(memcg)) |
3384 | return; |
3385 | |
3386 | mutex_lock(&memcg->slab_caches_mutex); |
3387 | list_for_each_entry(params, &memcg->memcg_slab_caches, list) { |
3388 | cachep = memcg_params_to_cache(params); |
3389 | cachep->memcg_params->dead = true; |
3390 | schedule_work(&cachep->memcg_params->destroy); |
3391 | } |
3392 | mutex_unlock(&memcg->slab_caches_mutex); |
3393 | } |
3394 | |
3395 | struct create_work { |
3396 | struct mem_cgroup *memcg; |
3397 | struct kmem_cache *cachep; |
3398 | struct work_struct work; |
3399 | }; |
3400 | |
3401 | static void memcg_create_cache_work_func(struct work_struct *w) |
3402 | { |
3403 | struct create_work *cw = container_of(w, struct create_work, work); |
3404 | struct mem_cgroup *memcg = cw->memcg; |
3405 | struct kmem_cache *cachep = cw->cachep; |
3406 | |
3407 | kmem_cache_create_memcg(memcg, cachep); |
3408 | css_put(&memcg->css); |
3409 | kfree(cw); |
3410 | } |
3411 | |
3412 | /* |
3413 | * Enqueue the creation of a per-memcg kmem_cache. |
3414 | */ |
3415 | static void __memcg_create_cache_enqueue(struct mem_cgroup *memcg, |
3416 | struct kmem_cache *cachep) |
3417 | { |
3418 | struct create_work *cw; |
3419 | |
3420 | cw = kmalloc(sizeof(struct create_work), GFP_NOWAIT); |
3421 | if (cw == NULL) { |
3422 | css_put(&memcg->css); |
3423 | return; |
3424 | } |
3425 | |
3426 | cw->memcg = memcg; |
3427 | cw->cachep = cachep; |
3428 | |
3429 | INIT_WORK(&cw->work, memcg_create_cache_work_func); |
3430 | schedule_work(&cw->work); |
3431 | } |
3432 | |
3433 | static void memcg_create_cache_enqueue(struct mem_cgroup *memcg, |
3434 | struct kmem_cache *cachep) |
3435 | { |
3436 | /* |
3437 | * We need to stop accounting when we kmalloc, because if the |
3438 | * corresponding kmalloc cache is not yet created, the first allocation |
3439 | * in __memcg_create_cache_enqueue will recurse. |
3440 | * |
3441 | * However, it is better to enclose the whole function. Depending on |
3442 | * the debugging options enabled, INIT_WORK(), for instance, can |
3443 | * trigger an allocation. This too, will make us recurse. Because at |
3444 | * this point we can't allow ourselves back into memcg_kmem_get_cache, |
3445 | * the safest choice is to do it like this, wrapping the whole function. |
3446 | */ |
3447 | memcg_stop_kmem_account(); |
3448 | __memcg_create_cache_enqueue(memcg, cachep); |
3449 | memcg_resume_kmem_account(); |
3450 | } |
3451 | /* |
3452 | * Return the kmem_cache we're supposed to use for a slab allocation. |
3453 | * We try to use the current memcg's version of the cache. |
3454 | * |
3455 | * If the cache does not exist yet, if we are the first user of it, |
3456 | * we either create it immediately, if possible, or create it asynchronously |
3457 | * in a workqueue. |
3458 | * In the latter case, we will let the current allocation go through with |
3459 | * the original cache. |
3460 | * |
3461 | * Can't be called in interrupt context or from kernel threads. |
3462 | * This function needs to be called with rcu_read_lock() held. |
3463 | */ |
3464 | struct kmem_cache *__memcg_kmem_get_cache(struct kmem_cache *cachep, |
3465 | gfp_t gfp) |
3466 | { |
3467 | struct mem_cgroup *memcg; |
3468 | struct kmem_cache *memcg_cachep; |
3469 | |
3470 | VM_BUG_ON(!cachep->memcg_params); |
3471 | VM_BUG_ON(!cachep->memcg_params->is_root_cache); |
3472 | |
3473 | if (!current->mm || current->memcg_kmem_skip_account) |
3474 | return cachep; |
3475 | |
3476 | rcu_read_lock(); |
3477 | memcg = mem_cgroup_from_task(rcu_dereference(current->mm->owner)); |
3478 | |
3479 | if (!memcg_can_account_kmem(memcg)) |
3480 | goto out; |
3481 | |
3482 | memcg_cachep = cache_from_memcg_idx(cachep, memcg_cache_id(memcg)); |
3483 | if (likely(memcg_cachep)) { |
3484 | cachep = memcg_cachep; |
3485 | goto out; |
3486 | } |
3487 | |
3488 | /* The corresponding put will be done in the workqueue. */ |
3489 | if (!css_tryget(&memcg->css)) |
3490 | goto out; |
3491 | rcu_read_unlock(); |
3492 | |
3493 | /* |
3494 | * If we are in a safe context (can wait, and not in interrupt |
3495 | * context), we could be be predictable and return right away. |
3496 | * This would guarantee that the allocation being performed |
3497 | * already belongs in the new cache. |
3498 | * |
3499 | * However, there are some clashes that can arrive from locking. |
3500 | * For instance, because we acquire the slab_mutex while doing |
3501 | * kmem_cache_dup, this means no further allocation could happen |
3502 | * with the slab_mutex held. |
3503 | * |
3504 | * Also, because cache creation issue get_online_cpus(), this |
3505 | * creates a lock chain: memcg_slab_mutex -> cpu_hotplug_mutex, |
3506 | * that ends up reversed during cpu hotplug. (cpuset allocates |
3507 | * a bunch of GFP_KERNEL memory during cpuup). Due to all that, |
3508 | * better to defer everything. |
3509 | */ |
3510 | memcg_create_cache_enqueue(memcg, cachep); |
3511 | return cachep; |
3512 | out: |
3513 | rcu_read_unlock(); |
3514 | return cachep; |
3515 | } |
3516 | EXPORT_SYMBOL(__memcg_kmem_get_cache); |
3517 | |
3518 | /* |
3519 | * We need to verify if the allocation against current->mm->owner's memcg is |
3520 | * possible for the given order. But the page is not allocated yet, so we'll |
3521 | * need a further commit step to do the final arrangements. |
3522 | * |
3523 | * It is possible for the task to switch cgroups in this mean time, so at |
3524 | * commit time, we can't rely on task conversion any longer. We'll then use |
3525 | * the handle argument to return to the caller which cgroup we should commit |
3526 | * against. We could also return the memcg directly and avoid the pointer |
3527 | * passing, but a boolean return value gives better semantics considering |
3528 | * the compiled-out case as well. |
3529 | * |
3530 | * Returning true means the allocation is possible. |
3531 | */ |
3532 | bool |
3533 | __memcg_kmem_newpage_charge(gfp_t gfp, struct mem_cgroup **_memcg, int order) |
3534 | { |
3535 | struct mem_cgroup *memcg; |
3536 | int ret; |
3537 | |
3538 | *_memcg = NULL; |
3539 | |
3540 | /* |
3541 | * Disabling accounting is only relevant for some specific memcg |
3542 | * internal allocations. Therefore we would initially not have such |
3543 | * check here, since direct calls to the page allocator that are marked |
3544 | * with GFP_KMEMCG only happen outside memcg core. We are mostly |
3545 | * concerned with cache allocations, and by having this test at |
3546 | * memcg_kmem_get_cache, we are already able to relay the allocation to |
3547 | * the root cache and bypass the memcg cache altogether. |
3548 | * |
3549 | * There is one exception, though: the SLUB allocator does not create |
3550 | * large order caches, but rather service large kmallocs directly from |
3551 | * the page allocator. Therefore, the following sequence when backed by |
3552 | * the SLUB allocator: |
3553 | * |
3554 | * memcg_stop_kmem_account(); |
3555 | * kmalloc(<large_number>) |
3556 | * memcg_resume_kmem_account(); |
3557 | * |
3558 | * would effectively ignore the fact that we should skip accounting, |
3559 | * since it will drive us directly to this function without passing |
3560 | * through the cache selector memcg_kmem_get_cache. Such large |
3561 | * allocations are extremely rare but can happen, for instance, for the |
3562 | * cache arrays. We bring this test here. |
3563 | */ |
3564 | if (!current->mm || current->memcg_kmem_skip_account) |
3565 | return true; |
3566 | |
3567 | memcg = get_mem_cgroup_from_mm(current->mm); |
3568 | |
3569 | if (!memcg_can_account_kmem(memcg)) { |
3570 | css_put(&memcg->css); |
3571 | return true; |
3572 | } |
3573 | |
3574 | ret = memcg_charge_kmem(memcg, gfp, PAGE_SIZE << order); |
3575 | if (!ret) |
3576 | *_memcg = memcg; |
3577 | |
3578 | css_put(&memcg->css); |
3579 | return (ret == 0); |
3580 | } |
3581 | |
3582 | void __memcg_kmem_commit_charge(struct page *page, struct mem_cgroup *memcg, |
3583 | int order) |
3584 | { |
3585 | struct page_cgroup *pc; |
3586 | |
3587 | VM_BUG_ON(mem_cgroup_is_root(memcg)); |
3588 | |
3589 | /* The page allocation failed. Revert */ |
3590 | if (!page) { |
3591 | memcg_uncharge_kmem(memcg, PAGE_SIZE << order); |
3592 | return; |
3593 | } |
3594 | |
3595 | pc = lookup_page_cgroup(page); |
3596 | lock_page_cgroup(pc); |
3597 | pc->mem_cgroup = memcg; |
3598 | SetPageCgroupUsed(pc); |
3599 | unlock_page_cgroup(pc); |
3600 | } |
3601 | |
3602 | void __memcg_kmem_uncharge_pages(struct page *page, int order) |
3603 | { |
3604 | struct mem_cgroup *memcg = NULL; |
3605 | struct page_cgroup *pc; |
3606 | |
3607 | |
3608 | pc = lookup_page_cgroup(page); |
3609 | /* |
3610 | * Fast unlocked return. Theoretically might have changed, have to |
3611 | * check again after locking. |
3612 | */ |
3613 | if (!PageCgroupUsed(pc)) |
3614 | return; |
3615 | |
3616 | lock_page_cgroup(pc); |
3617 | if (PageCgroupUsed(pc)) { |
3618 | memcg = pc->mem_cgroup; |
3619 | ClearPageCgroupUsed(pc); |
3620 | } |
3621 | unlock_page_cgroup(pc); |
3622 | |
3623 | /* |
3624 | * We trust that only if there is a memcg associated with the page, it |
3625 | * is a valid allocation |
3626 | */ |
3627 | if (!memcg) |
3628 | return; |
3629 | |
3630 | VM_BUG_ON_PAGE(mem_cgroup_is_root(memcg), page); |
3631 | memcg_uncharge_kmem(memcg, PAGE_SIZE << order); |
3632 | } |
3633 | #else |
3634 | static inline void mem_cgroup_destroy_all_caches(struct mem_cgroup *memcg) |
3635 | { |
3636 | } |
3637 | #endif /* CONFIG_MEMCG_KMEM */ |
3638 | |
3639 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE |
3640 | |
3641 | #define PCGF_NOCOPY_AT_SPLIT (1 << PCG_LOCK | 1 << PCG_MIGRATION) |
3642 | /* |
3643 | * Because tail pages are not marked as "used", set it. We're under |
3644 | * zone->lru_lock, 'splitting on pmd' and compound_lock. |
3645 | * charge/uncharge will be never happen and move_account() is done under |
3646 | * compound_lock(), so we don't have to take care of races. |
3647 | */ |
3648 | void mem_cgroup_split_huge_fixup(struct page *head) |
3649 | { |
3650 | struct page_cgroup *head_pc = lookup_page_cgroup(head); |
3651 | struct page_cgroup *pc; |
3652 | struct mem_cgroup *memcg; |
3653 | int i; |
3654 | |
3655 | if (mem_cgroup_disabled()) |
3656 | return; |
3657 | |
3658 | memcg = head_pc->mem_cgroup; |
3659 | for (i = 1; i < HPAGE_PMD_NR; i++) { |
3660 | pc = head_pc + i; |
3661 | pc->mem_cgroup = memcg; |
3662 | smp_wmb();/* see __commit_charge() */ |
3663 | pc->flags = head_pc->flags & ~PCGF_NOCOPY_AT_SPLIT; |
3664 | } |
3665 | __this_cpu_sub(memcg->stat->count[MEM_CGROUP_STAT_RSS_HUGE], |
3666 | HPAGE_PMD_NR); |
3667 | } |
3668 | #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ |
3669 | |
3670 | /** |
3671 | * mem_cgroup_move_account - move account of the page |
3672 | * @page: the page |
3673 | * @nr_pages: number of regular pages (>1 for huge pages) |
3674 | * @pc: page_cgroup of the page. |
3675 | * @from: mem_cgroup which the page is moved from. |
3676 | * @to: mem_cgroup which the page is moved to. @from != @to. |
3677 | * |
3678 | * The caller must confirm following. |
3679 | * - page is not on LRU (isolate_page() is useful.) |
3680 | * - compound_lock is held when nr_pages > 1 |
3681 | * |
3682 | * This function doesn't do "charge" to new cgroup and doesn't do "uncharge" |
3683 | * from old cgroup. |
3684 | */ |
3685 | static int mem_cgroup_move_account(struct page *page, |
3686 | unsigned int nr_pages, |
3687 | struct page_cgroup *pc, |
3688 | struct mem_cgroup *from, |
3689 | struct mem_cgroup *to) |
3690 | { |
3691 | unsigned long flags; |
3692 | int ret; |
3693 | bool anon = PageAnon(page); |
3694 | |
3695 | VM_BUG_ON(from == to); |
3696 | VM_BUG_ON_PAGE(PageLRU(page), page); |
3697 | /* |
3698 | * The page is isolated from LRU. So, collapse function |
3699 | * will not handle this page. But page splitting can happen. |
3700 | * Do this check under compound_page_lock(). The caller should |
3701 | * hold it. |
3702 | */ |
3703 | ret = -EBUSY; |
3704 | if (nr_pages > 1 && !PageTransHuge(page)) |
3705 | goto out; |
3706 | |
3707 | lock_page_cgroup(pc); |
3708 | |
3709 | ret = -EINVAL; |
3710 | if (!PageCgroupUsed(pc) || pc->mem_cgroup != from) |
3711 | goto unlock; |
3712 | |
3713 | move_lock_mem_cgroup(from, &flags); |
3714 | |
3715 | if (!anon && page_mapped(page)) { |
3716 | __this_cpu_sub(from->stat->count[MEM_CGROUP_STAT_FILE_MAPPED], |
3717 | nr_pages); |
3718 | __this_cpu_add(to->stat->count[MEM_CGROUP_STAT_FILE_MAPPED], |
3719 | nr_pages); |
3720 | } |
3721 | |
3722 | if (PageWriteback(page)) { |
3723 | __this_cpu_sub(from->stat->count[MEM_CGROUP_STAT_WRITEBACK], |
3724 | nr_pages); |
3725 | __this_cpu_add(to->stat->count[MEM_CGROUP_STAT_WRITEBACK], |
3726 | nr_pages); |
3727 | } |
3728 | |
3729 | mem_cgroup_charge_statistics(from, page, anon, -nr_pages); |
3730 | |
3731 | /* caller should have done css_get */ |
3732 | pc->mem_cgroup = to; |
3733 | mem_cgroup_charge_statistics(to, page, anon, nr_pages); |
3734 | move_unlock_mem_cgroup(from, &flags); |
3735 | ret = 0; |
3736 | unlock: |
3737 | unlock_page_cgroup(pc); |
3738 | /* |
3739 | * check events |
3740 | */ |
3741 | memcg_check_events(to, page); |
3742 | memcg_check_events(from, page); |
3743 | out: |
3744 | return ret; |
3745 | } |
3746 | |
3747 | /** |
3748 | * mem_cgroup_move_parent - moves page to the parent group |
3749 | * @page: the page to move |
3750 | * @pc: page_cgroup of the page |
3751 | * @child: page's cgroup |
3752 | * |
3753 | * move charges to its parent or the root cgroup if the group has no |
3754 | * parent (aka use_hierarchy==0). |
3755 | * Although this might fail (get_page_unless_zero, isolate_lru_page or |
3756 | * mem_cgroup_move_account fails) the failure is always temporary and |
3757 | * it signals a race with a page removal/uncharge or migration. In the |
3758 | * first case the page is on the way out and it will vanish from the LRU |
3759 | * on the next attempt and the call should be retried later. |
3760 | * Isolation from the LRU fails only if page has been isolated from |
3761 | * the LRU since we looked at it and that usually means either global |
3762 | * reclaim or migration going on. The page will either get back to the |
3763 | * LRU or vanish. |
3764 | * Finaly mem_cgroup_move_account fails only if the page got uncharged |
3765 | * (!PageCgroupUsed) or moved to a different group. The page will |
3766 | * disappear in the next attempt. |
3767 | */ |
3768 | static int mem_cgroup_move_parent(struct page *page, |
3769 | struct page_cgroup *pc, |
3770 | struct mem_cgroup *child) |
3771 | { |
3772 | struct mem_cgroup *parent; |
3773 | unsigned int nr_pages; |
3774 | unsigned long uninitialized_var(flags); |
3775 | int ret; |
3776 | |
3777 | VM_BUG_ON(mem_cgroup_is_root(child)); |
3778 | |
3779 | ret = -EBUSY; |
3780 | if (!get_page_unless_zero(page)) |
3781 | goto out; |
3782 | if (isolate_lru_page(page)) |
3783 | goto put; |
3784 | |
3785 | nr_pages = hpage_nr_pages(page); |
3786 | |
3787 | parent = parent_mem_cgroup(child); |
3788 | /* |
3789 | * If no parent, move charges to root cgroup. |
3790 | */ |
3791 | if (!parent) |
3792 | parent = root_mem_cgroup; |
3793 | |
3794 | if (nr_pages > 1) { |
3795 | VM_BUG_ON_PAGE(!PageTransHuge(page), page); |
3796 | flags = compound_lock_irqsave(page); |
3797 | } |
3798 | |
3799 | ret = mem_cgroup_move_account(page, nr_pages, |
3800 | pc, child, parent); |
3801 | if (!ret) |
3802 | __mem_cgroup_cancel_local_charge(child, nr_pages); |
3803 | |
3804 | if (nr_pages > 1) |
3805 | compound_unlock_irqrestore(page, flags); |
3806 | putback_lru_page(page); |
3807 | put: |
3808 | put_page(page); |
3809 | out: |
3810 | return ret; |
3811 | } |
3812 | |
3813 | int mem_cgroup_charge_anon(struct page *page, |
3814 | struct mm_struct *mm, gfp_t gfp_mask) |
3815 | { |
3816 | unsigned int nr_pages = 1; |
3817 | struct mem_cgroup *memcg; |
3818 | bool oom = true; |
3819 | |
3820 | if (mem_cgroup_disabled()) |
3821 | return 0; |
3822 | |
3823 | VM_BUG_ON_PAGE(page_mapped(page), page); |
3824 | VM_BUG_ON_PAGE(page->mapping && !PageAnon(page), page); |
3825 | VM_BUG_ON(!mm); |
3826 | |
3827 | if (PageTransHuge(page)) { |
3828 | nr_pages <<= compound_order(page); |
3829 | VM_BUG_ON_PAGE(!PageTransHuge(page), page); |
3830 | /* |
3831 | * Never OOM-kill a process for a huge page. The |
3832 | * fault handler will fall back to regular pages. |
3833 | */ |
3834 | oom = false; |
3835 | } |
3836 | |
3837 | memcg = mem_cgroup_try_charge_mm(mm, gfp_mask, nr_pages, oom); |
3838 | if (!memcg) |
3839 | return -ENOMEM; |
3840 | __mem_cgroup_commit_charge(memcg, page, nr_pages, |
3841 | MEM_CGROUP_CHARGE_TYPE_ANON, false); |
3842 | return 0; |
3843 | } |
3844 | |
3845 | /* |
3846 | * While swap-in, try_charge -> commit or cancel, the page is locked. |
3847 | * And when try_charge() successfully returns, one refcnt to memcg without |
3848 | * struct page_cgroup is acquired. This refcnt will be consumed by |
3849 | * "commit()" or removed by "cancel()" |
3850 | */ |
3851 | static int __mem_cgroup_try_charge_swapin(struct mm_struct *mm, |
3852 | struct page *page, |
3853 | gfp_t mask, |
3854 | struct mem_cgroup **memcgp) |
3855 | { |
3856 | struct mem_cgroup *memcg = NULL; |
3857 | struct page_cgroup *pc; |
3858 | int ret; |
3859 | |
3860 | pc = lookup_page_cgroup(page); |
3861 | /* |
3862 | * Every swap fault against a single page tries to charge the |
3863 | * page, bail as early as possible. shmem_unuse() encounters |
3864 | * already charged pages, too. The USED bit is protected by |
3865 | * the page lock, which serializes swap cache removal, which |
3866 | * in turn serializes uncharging. |
3867 | */ |
3868 | if (PageCgroupUsed(pc)) |
3869 | goto out; |
3870 | if (do_swap_account) |
3871 | memcg = try_get_mem_cgroup_from_page(page); |
3872 | if (!memcg) |
3873 | memcg = get_mem_cgroup_from_mm(mm); |
3874 | ret = mem_cgroup_try_charge(memcg, mask, 1, true); |
3875 | css_put(&memcg->css); |
3876 | if (ret == -EINTR) |
3877 | memcg = root_mem_cgroup; |
3878 | else if (ret) |
3879 | return ret; |
3880 | out: |
3881 | *memcgp = memcg; |
3882 | return 0; |
3883 | } |
3884 | |
3885 | int mem_cgroup_try_charge_swapin(struct mm_struct *mm, struct page *page, |
3886 | gfp_t gfp_mask, struct mem_cgroup **memcgp) |
3887 | { |
3888 | if (mem_cgroup_disabled()) { |
3889 | *memcgp = NULL; |
3890 | return 0; |
3891 | } |
3892 | /* |
3893 | * A racing thread's fault, or swapoff, may have already |
3894 | * updated the pte, and even removed page from swap cache: in |
3895 | * those cases unuse_pte()'s pte_same() test will fail; but |
3896 | * there's also a KSM case which does need to charge the page. |
3897 | */ |
3898 | if (!PageSwapCache(page)) { |
3899 | struct mem_cgroup *memcg; |
3900 | |
3901 | memcg = mem_cgroup_try_charge_mm(mm, gfp_mask, 1, true); |
3902 | if (!memcg) |
3903 | return -ENOMEM; |
3904 | *memcgp = memcg; |
3905 | return 0; |
3906 | } |
3907 | return __mem_cgroup_try_charge_swapin(mm, page, gfp_mask, memcgp); |
3908 | } |
3909 | |
3910 | void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *memcg) |
3911 | { |
3912 | if (mem_cgroup_disabled()) |
3913 | return; |
3914 | if (!memcg) |
3915 | return; |
3916 | __mem_cgroup_cancel_charge(memcg, 1); |
3917 | } |
3918 | |
3919 | static void |
3920 | __mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *memcg, |
3921 | enum charge_type ctype) |
3922 | { |
3923 | if (mem_cgroup_disabled()) |
3924 | return; |
3925 | if (!memcg) |
3926 | return; |
3927 | |
3928 | __mem_cgroup_commit_charge(memcg, page, 1, ctype, true); |
3929 | /* |
3930 | * Now swap is on-memory. This means this page may be |
3931 | * counted both as mem and swap....double count. |
3932 | * Fix it by uncharging from memsw. Basically, this SwapCache is stable |
3933 | * under lock_page(). But in do_swap_page()::memory.c, reuse_swap_page() |
3934 | * may call delete_from_swap_cache() before reach here. |
3935 | */ |
3936 | if (do_swap_account && PageSwapCache(page)) { |
3937 | swp_entry_t ent = {.val = page_private(page)}; |
3938 | mem_cgroup_uncharge_swap(ent); |
3939 | } |
3940 | } |
3941 | |
3942 | void mem_cgroup_commit_charge_swapin(struct page *page, |
3943 | struct mem_cgroup *memcg) |
3944 | { |
3945 | __mem_cgroup_commit_charge_swapin(page, memcg, |
3946 | MEM_CGROUP_CHARGE_TYPE_ANON); |
3947 | } |
3948 | |
3949 | int mem_cgroup_charge_file(struct page *page, struct mm_struct *mm, |
3950 | gfp_t gfp_mask) |
3951 | { |
3952 | enum charge_type type = MEM_CGROUP_CHARGE_TYPE_CACHE; |
3953 | struct mem_cgroup *memcg; |
3954 | int ret; |
3955 | |
3956 | if (mem_cgroup_disabled()) |
3957 | return 0; |
3958 | if (PageCompound(page)) |
3959 | return 0; |
3960 | |
3961 | if (PageSwapCache(page)) { /* shmem */ |
3962 | ret = __mem_cgroup_try_charge_swapin(mm, page, |
3963 | gfp_mask, &memcg); |
3964 | if (ret) |
3965 | return ret; |
3966 | __mem_cgroup_commit_charge_swapin(page, memcg, type); |
3967 | return 0; |
3968 | } |
3969 | |
3970 | memcg = mem_cgroup_try_charge_mm(mm, gfp_mask, 1, true); |
3971 | if (!memcg) |
3972 | return -ENOMEM; |
3973 | __mem_cgroup_commit_charge(memcg, page, 1, type, false); |
3974 | return 0; |
3975 | } |
3976 | |
3977 | static void mem_cgroup_do_uncharge(struct mem_cgroup *memcg, |
3978 | unsigned int nr_pages, |
3979 | const enum charge_type ctype) |
3980 | { |
3981 | struct memcg_batch_info *batch = NULL; |
3982 | bool uncharge_memsw = true; |
3983 | |
3984 | /* If swapout, usage of swap doesn't decrease */ |
3985 | if (!do_swap_account || ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT) |
3986 | uncharge_memsw = false; |
3987 | |
3988 | batch = ¤t->memcg_batch; |
3989 | /* |
3990 | * In usual, we do css_get() when we remember memcg pointer. |
3991 | * But in this case, we keep res->usage until end of a series of |
3992 | * uncharges. Then, it's ok to ignore memcg's refcnt. |
3993 | */ |
3994 | if (!batch->memcg) |
3995 | batch->memcg = memcg; |
3996 | /* |
3997 | * do_batch > 0 when unmapping pages or inode invalidate/truncate. |
3998 | * In those cases, all pages freed continuously can be expected to be in |
3999 | * the same cgroup and we have chance to coalesce uncharges. |
4000 | * But we do uncharge one by one if this is killed by OOM(TIF_MEMDIE) |
4001 | * because we want to do uncharge as soon as possible. |
4002 | */ |
4003 | |
4004 | if (!batch->do_batch || test_thread_flag(TIF_MEMDIE)) |
4005 | goto direct_uncharge; |
4006 | |
4007 | if (nr_pages > 1) |
4008 | goto direct_uncharge; |
4009 | |
4010 | /* |
4011 | * In typical case, batch->memcg == mem. This means we can |
4012 | * merge a series of uncharges to an uncharge of res_counter. |
4013 | * If not, we uncharge res_counter ony by one. |
4014 | */ |
4015 | if (batch->memcg != memcg) |
4016 | goto direct_uncharge; |
4017 | /* remember freed charge and uncharge it later */ |
4018 | batch->nr_pages++; |
4019 | if (uncharge_memsw) |
4020 | batch->memsw_nr_pages++; |
4021 | return; |
4022 | direct_uncharge: |
4023 | res_counter_uncharge(&memcg->res, nr_pages * PAGE_SIZE); |
4024 | if (uncharge_memsw) |
4025 | res_counter_uncharge(&memcg->memsw, nr_pages * PAGE_SIZE); |
4026 | if (unlikely(batch->memcg != memcg)) |
4027 | memcg_oom_recover(memcg); |
4028 | } |
4029 | |
4030 | /* |
4031 | * uncharge if !page_mapped(page) |
4032 | */ |
4033 | static struct mem_cgroup * |
4034 | __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype, |
4035 | bool end_migration) |
4036 | { |
4037 | struct mem_cgroup *memcg = NULL; |
4038 | unsigned int nr_pages = 1; |
4039 | struct page_cgroup *pc; |
4040 | bool anon; |
4041 | |
4042 | if (mem_cgroup_disabled()) |
4043 | return NULL; |
4044 | |
4045 | if (PageTransHuge(page)) { |
4046 | nr_pages <<= compound_order(page); |
4047 | VM_BUG_ON_PAGE(!PageTransHuge(page), page); |
4048 | } |
4049 | /* |
4050 | * Check if our page_cgroup is valid |
4051 | */ |
4052 | pc = lookup_page_cgroup(page); |
4053 | if (unlikely(!PageCgroupUsed(pc))) |
4054 | return NULL; |
4055 | |
4056 | lock_page_cgroup(pc); |
4057 | |
4058 | memcg = pc->mem_cgroup; |
4059 | |
4060 | if (!PageCgroupUsed(pc)) |
4061 | goto unlock_out; |
4062 | |
4063 | anon = PageAnon(page); |
4064 | |
4065 | switch (ctype) { |
4066 | case MEM_CGROUP_CHARGE_TYPE_ANON: |
4067 | /* |
4068 | * Generally PageAnon tells if it's the anon statistics to be |
4069 | * updated; but sometimes e.g. mem_cgroup_uncharge_page() is |
4070 | * used before page reached the stage of being marked PageAnon. |
4071 | */ |
4072 | anon = true; |
4073 | /* fallthrough */ |
4074 | case MEM_CGROUP_CHARGE_TYPE_DROP: |
4075 | /* See mem_cgroup_prepare_migration() */ |
4076 | if (page_mapped(page)) |
4077 | goto unlock_out; |
4078 | /* |
4079 | * Pages under migration may not be uncharged. But |
4080 | * end_migration() /must/ be the one uncharging the |
4081 | * unused post-migration page and so it has to call |
4082 | * here with the migration bit still set. See the |
4083 | * res_counter handling below. |
4084 | */ |
4085 | if (!end_migration && PageCgroupMigration(pc)) |
4086 | goto unlock_out; |
4087 | break; |
4088 | case MEM_CGROUP_CHARGE_TYPE_SWAPOUT: |
4089 | if (!PageAnon(page)) { /* Shared memory */ |
4090 | if (page->mapping && !page_is_file_cache(page)) |
4091 | goto unlock_out; |
4092 | } else if (page_mapped(page)) /* Anon */ |
4093 | goto unlock_out; |
4094 | break; |
4095 | default: |
4096 | break; |
4097 | } |
4098 | |
4099 | mem_cgroup_charge_statistics(memcg, page, anon, -nr_pages); |
4100 | |
4101 | ClearPageCgroupUsed(pc); |
4102 | /* |
4103 | * pc->mem_cgroup is not cleared here. It will be accessed when it's |
4104 | * freed from LRU. This is safe because uncharged page is expected not |
4105 | * to be reused (freed soon). Exception is SwapCache, it's handled by |
4106 | * special functions. |
4107 | */ |
4108 | |
4109 | unlock_page_cgroup(pc); |
4110 | /* |
4111 | * even after unlock, we have memcg->res.usage here and this memcg |
4112 | * will never be freed, so it's safe to call css_get(). |
4113 | */ |
4114 | memcg_check_events(memcg, page); |
4115 | if (do_swap_account && ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT) { |
4116 | mem_cgroup_swap_statistics(memcg, true); |
4117 | css_get(&memcg->css); |
4118 | } |
4119 | /* |
4120 | * Migration does not charge the res_counter for the |
4121 | * replacement page, so leave it alone when phasing out the |
4122 | * page that is unused after the migration. |
4123 | */ |
4124 | if (!end_migration && !mem_cgroup_is_root(memcg)) |
4125 | mem_cgroup_do_uncharge(memcg, nr_pages, ctype); |
4126 | |
4127 | return memcg; |
4128 | |
4129 | unlock_out: |
4130 | unlock_page_cgroup(pc); |
4131 | return NULL; |
4132 | } |
4133 | |
4134 | void mem_cgroup_uncharge_page(struct page *page) |
4135 | { |
4136 | /* early check. */ |
4137 | if (page_mapped(page)) |
4138 | return; |
4139 | VM_BUG_ON_PAGE(page->mapping && !PageAnon(page), page); |
4140 | /* |
4141 | * If the page is in swap cache, uncharge should be deferred |
4142 | * to the swap path, which also properly accounts swap usage |
4143 | * and handles memcg lifetime. |
4144 | * |
4145 | * Note that this check is not stable and reclaim may add the |
4146 | * page to swap cache at any time after this. However, if the |
4147 | * page is not in swap cache by the time page->mapcount hits |
4148 | * 0, there won't be any page table references to the swap |
4149 | * slot, and reclaim will free it and not actually write the |
4150 | * page to disk. |
4151 | */ |
4152 | if (PageSwapCache(page)) |
4153 | return; |
4154 | __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_ANON, false); |
4155 | } |
4156 | |
4157 | void mem_cgroup_uncharge_cache_page(struct page *page) |
4158 | { |
4159 | VM_BUG_ON_PAGE(page_mapped(page), page); |
4160 | VM_BUG_ON_PAGE(page->mapping, page); |
4161 | __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE, false); |
4162 | } |
4163 | |
4164 | /* |
4165 | * Batch_start/batch_end is called in unmap_page_range/invlidate/trucate. |
4166 | * In that cases, pages are freed continuously and we can expect pages |
4167 | * are in the same memcg. All these calls itself limits the number of |
4168 | * pages freed at once, then uncharge_start/end() is called properly. |
4169 | * This may be called prural(2) times in a context, |
4170 | */ |
4171 | |
4172 | void mem_cgroup_uncharge_start(void) |
4173 | { |
4174 | current->memcg_batch.do_batch++; |
4175 | /* We can do nest. */ |
4176 | if (current->memcg_batch.do_batch == 1) { |
4177 | current->memcg_batch.memcg = NULL; |
4178 | current->memcg_batch.nr_pages = 0; |
4179 | current->memcg_batch.memsw_nr_pages = 0; |
4180 | } |
4181 | } |
4182 | |
4183 | void mem_cgroup_uncharge_end(void) |
4184 | { |
4185 | struct memcg_batch_info *batch = ¤t->memcg_batch; |
4186 | |
4187 | if (!batch->do_batch) |
4188 | return; |
4189 | |
4190 | batch->do_batch--; |
4191 | if (batch->do_batch) /* If stacked, do nothing. */ |
4192 | return; |
4193 | |
4194 | if (!batch->memcg) |
4195 | return; |
4196 | /* |
4197 | * This "batch->memcg" is valid without any css_get/put etc... |
4198 | * bacause we hide charges behind us. |
4199 | */ |
4200 | if (batch->nr_pages) |
4201 | res_counter_uncharge(&batch->memcg->res, |
4202 | batch->nr_pages * PAGE_SIZE); |
4203 | if (batch->memsw_nr_pages) |
4204 | res_counter_uncharge(&batch->memcg->memsw, |
4205 | batch->memsw_nr_pages * PAGE_SIZE); |
4206 | memcg_oom_recover(batch->memcg); |
4207 | /* forget this pointer (for sanity check) */ |
4208 | batch->memcg = NULL; |
4209 | } |
4210 | |
4211 | #ifdef CONFIG_SWAP |
4212 | /* |
4213 | * called after __delete_from_swap_cache() and drop "page" account. |
4214 | * memcg information is recorded to swap_cgroup of "ent" |
4215 | */ |
4216 | void |
4217 | mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout) |
4218 | { |
4219 | struct mem_cgroup *memcg; |
4220 | int ctype = MEM_CGROUP_CHARGE_TYPE_SWAPOUT; |
4221 | |
4222 | if (!swapout) /* this was a swap cache but the swap is unused ! */ |
4223 | ctype = MEM_CGROUP_CHARGE_TYPE_DROP; |
4224 | |
4225 | memcg = __mem_cgroup_uncharge_common(page, ctype, false); |
4226 | |
4227 | /* |
4228 | * record memcg information, if swapout && memcg != NULL, |
4229 | * css_get() was called in uncharge(). |
4230 | */ |
4231 | if (do_swap_account && swapout && memcg) |
4232 | swap_cgroup_record(ent, mem_cgroup_id(memcg)); |
4233 | } |
4234 | #endif |
4235 | |
4236 | #ifdef CONFIG_MEMCG_SWAP |
4237 | /* |
4238 | * called from swap_entry_free(). remove record in swap_cgroup and |
4239 | * uncharge "memsw" account. |
4240 | */ |
4241 | void mem_cgroup_uncharge_swap(swp_entry_t ent) |
4242 | { |
4243 | struct mem_cgroup *memcg; |
4244 | unsigned short id; |
4245 | |
4246 | if (!do_swap_account) |
4247 | return; |
4248 | |
4249 | id = swap_cgroup_record(ent, 0); |
4250 | rcu_read_lock(); |
4251 | memcg = mem_cgroup_lookup(id); |
4252 | if (memcg) { |
4253 | /* |
4254 | * We uncharge this because swap is freed. |
4255 | * This memcg can be obsolete one. We avoid calling css_tryget |
4256 | */ |
4257 | if (!mem_cgroup_is_root(memcg)) |
4258 | res_counter_uncharge(&memcg->memsw, PAGE_SIZE); |
4259 | mem_cgroup_swap_statistics(memcg, false); |
4260 | css_put(&memcg->css); |
4261 | } |
4262 | rcu_read_unlock(); |
4263 | } |
4264 | |
4265 | /** |
4266 | * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record. |
4267 | * @entry: swap entry to be moved |
4268 | * @from: mem_cgroup which the entry is moved from |
4269 | * @to: mem_cgroup which the entry is moved to |
4270 | * |
4271 | * It succeeds only when the swap_cgroup's record for this entry is the same |
4272 | * as the mem_cgroup's id of @from. |
4273 | * |
4274 | * Returns 0 on success, -EINVAL on failure. |
4275 | * |
4276 | * The caller must have charged to @to, IOW, called res_counter_charge() about |
4277 | * both res and memsw, and called css_get(). |
4278 | */ |
4279 | static int mem_cgroup_move_swap_account(swp_entry_t entry, |
4280 | struct mem_cgroup *from, struct mem_cgroup *to) |
4281 | { |
4282 | unsigned short old_id, new_id; |
4283 | |
4284 | old_id = mem_cgroup_id(from); |
4285 | new_id = mem_cgroup_id(to); |
4286 | |
4287 | if (swap_cgroup_cmpxchg(entry, old_id, new_id) == old_id) { |
4288 | mem_cgroup_swap_statistics(from, false); |
4289 | mem_cgroup_swap_statistics(to, true); |
4290 | /* |
4291 | * This function is only called from task migration context now. |
4292 | * It postpones res_counter and refcount handling till the end |
4293 | * of task migration(mem_cgroup_clear_mc()) for performance |
4294 | * improvement. But we cannot postpone css_get(to) because if |
4295 | * the process that has been moved to @to does swap-in, the |
4296 | * refcount of @to might be decreased to 0. |
4297 | * |
4298 | * We are in attach() phase, so the cgroup is guaranteed to be |
4299 | * alive, so we can just call css_get(). |
4300 | */ |
4301 | css_get(&to->css); |
4302 | return 0; |
4303 | } |
4304 | return -EINVAL; |
4305 | } |
4306 | #else |
4307 | static inline int mem_cgroup_move_swap_account(swp_entry_t entry, |
4308 | struct mem_cgroup *from, struct mem_cgroup *to) |
4309 | { |
4310 | return -EINVAL; |
4311 | } |
4312 | #endif |
4313 | |
4314 | /* |
4315 | * Before starting migration, account PAGE_SIZE to mem_cgroup that the old |
4316 | * page belongs to. |
4317 | */ |
4318 | void mem_cgroup_prepare_migration(struct page *page, struct page *newpage, |
4319 | struct mem_cgroup **memcgp) |
4320 | { |
4321 | struct mem_cgroup *memcg = NULL; |
4322 | unsigned int nr_pages = 1; |
4323 | struct page_cgroup *pc; |
4324 | enum charge_type ctype; |
4325 | |
4326 | *memcgp = NULL; |
4327 | |
4328 | if (mem_cgroup_disabled()) |
4329 | return; |
4330 | |
4331 | if (PageTransHuge(page)) |
4332 | nr_pages <<= compound_order(page); |
4333 | |
4334 | pc = lookup_page_cgroup(page); |
4335 | lock_page_cgroup(pc); |
4336 | if (PageCgroupUsed(pc)) { |
4337 | memcg = pc->mem_cgroup; |
4338 | css_get(&memcg->css); |
4339 | /* |
4340 | * At migrating an anonymous page, its mapcount goes down |
4341 | * to 0 and uncharge() will be called. But, even if it's fully |
4342 | * unmapped, migration may fail and this page has to be |
4343 | * charged again. We set MIGRATION flag here and delay uncharge |
4344 | * until end_migration() is called |
4345 | * |
4346 | * Corner Case Thinking |
4347 | * A) |
4348 | * When the old page was mapped as Anon and it's unmap-and-freed |
4349 | * while migration was ongoing. |
4350 | * If unmap finds the old page, uncharge() of it will be delayed |
4351 | * until end_migration(). If unmap finds a new page, it's |
4352 | * uncharged when it make mapcount to be 1->0. If unmap code |
4353 | * finds swap_migration_entry, the new page will not be mapped |
4354 | * and end_migration() will find it(mapcount==0). |
4355 | * |
4356 | * B) |
4357 | * When the old page was mapped but migraion fails, the kernel |
4358 | * remaps it. A charge for it is kept by MIGRATION flag even |
4359 | * if mapcount goes down to 0. We can do remap successfully |
4360 | * without charging it again. |
4361 | * |
4362 | * C) |
4363 | * The "old" page is under lock_page() until the end of |
4364 | * migration, so, the old page itself will not be swapped-out. |
4365 | * If the new page is swapped out before end_migraton, our |
4366 | * hook to usual swap-out path will catch the event. |
4367 | */ |
4368 | if (PageAnon(page)) |
4369 | SetPageCgroupMigration(pc); |
4370 | } |
4371 | unlock_page_cgroup(pc); |
4372 | /* |
4373 | * If the page is not charged at this point, |
4374 | * we return here. |
4375 | */ |
4376 | if (!memcg) |
4377 | return; |
4378 | |
4379 | *memcgp = memcg; |
4380 | /* |
4381 | * We charge new page before it's used/mapped. So, even if unlock_page() |
4382 | * is called before end_migration, we can catch all events on this new |
4383 | * page. In the case new page is migrated but not remapped, new page's |
4384 | * mapcount will be finally 0 and we call uncharge in end_migration(). |
4385 | */ |
4386 | if (PageAnon(page)) |
4387 | ctype = MEM_CGROUP_CHARGE_TYPE_ANON; |
4388 | else |
4389 | ctype = MEM_CGROUP_CHARGE_TYPE_CACHE; |
4390 | /* |
4391 | * The page is committed to the memcg, but it's not actually |
4392 | * charged to the res_counter since we plan on replacing the |
4393 | * old one and only one page is going to be left afterwards. |
4394 | */ |
4395 | __mem_cgroup_commit_charge(memcg, newpage, nr_pages, ctype, false); |
4396 | } |
4397 | |
4398 | /* remove redundant charge if migration failed*/ |
4399 | void mem_cgroup_end_migration(struct mem_cgroup *memcg, |
4400 | struct page *oldpage, struct page *newpage, bool migration_ok) |
4401 | { |
4402 | struct page *used, *unused; |
4403 | struct page_cgroup *pc; |
4404 | bool anon; |
4405 | |
4406 | if (!memcg) |
4407 | return; |
4408 | |
4409 | if (!migration_ok) { |
4410 | used = oldpage; |
4411 | unused = newpage; |
4412 | } else { |
4413 | used = newpage; |
4414 | unused = oldpage; |
4415 | } |
4416 | anon = PageAnon(used); |
4417 | __mem_cgroup_uncharge_common(unused, |
4418 | anon ? MEM_CGROUP_CHARGE_TYPE_ANON |
4419 | : MEM_CGROUP_CHARGE_TYPE_CACHE, |
4420 | true); |
4421 | css_put(&memcg->css); |
4422 | /* |
4423 | * We disallowed uncharge of pages under migration because mapcount |
4424 | * of the page goes down to zero, temporarly. |
4425 | * Clear the flag and check the page should be charged. |
4426 | */ |
4427 | pc = lookup_page_cgroup(oldpage); |
4428 | lock_page_cgroup(pc); |
4429 | ClearPageCgroupMigration(pc); |
4430 | unlock_page_cgroup(pc); |
4431 | |
4432 | /* |
4433 | * If a page is a file cache, radix-tree replacement is very atomic |
4434 | * and we can skip this check. When it was an Anon page, its mapcount |
4435 | * goes down to 0. But because we added MIGRATION flage, it's not |
4436 | * uncharged yet. There are several case but page->mapcount check |
4437 | * and USED bit check in mem_cgroup_uncharge_page() will do enough |
4438 | * check. (see prepare_charge() also) |
4439 | */ |
4440 | if (anon) |
4441 | mem_cgroup_uncharge_page(used); |
4442 | } |
4443 | |
4444 | /* |
4445 | * At replace page cache, newpage is not under any memcg but it's on |
4446 | * LRU. So, this function doesn't touch res_counter but handles LRU |
4447 | * in correct way. Both pages are locked so we cannot race with uncharge. |
4448 | */ |
4449 | void mem_cgroup_replace_page_cache(struct page *oldpage, |
4450 | struct page *newpage) |
4451 | { |
4452 | struct mem_cgroup *memcg = NULL; |
4453 | struct page_cgroup *pc; |
4454 | enum charge_type type = MEM_CGROUP_CHARGE_TYPE_CACHE; |
4455 | |
4456 | if (mem_cgroup_disabled()) |
4457 | return; |
4458 | |
4459 | pc = lookup_page_cgroup(oldpage); |
4460 | /* fix accounting on old pages */ |
4461 | lock_page_cgroup(pc); |
4462 | if (PageCgroupUsed(pc)) { |
4463 | memcg = pc->mem_cgroup; |
4464 | mem_cgroup_charge_statistics(memcg, oldpage, false, -1); |
4465 | ClearPageCgroupUsed(pc); |
4466 | } |
4467 | unlock_page_cgroup(pc); |
4468 | |
4469 | /* |
4470 | * When called from shmem_replace_page(), in some cases the |
4471 | * oldpage has already been charged, and in some cases not. |
4472 | */ |
4473 | if (!memcg) |
4474 | return; |
4475 | /* |
4476 | * Even if newpage->mapping was NULL before starting replacement, |
4477 | * the newpage may be on LRU(or pagevec for LRU) already. We lock |
4478 | * LRU while we overwrite pc->mem_cgroup. |
4479 | */ |
4480 | __mem_cgroup_commit_charge(memcg, newpage, 1, type, true); |
4481 | } |
4482 | |
4483 | #ifdef CONFIG_DEBUG_VM |
4484 | static struct page_cgroup *lookup_page_cgroup_used(struct page *page) |
4485 | { |
4486 | struct page_cgroup *pc; |
4487 | |
4488 | pc = lookup_page_cgroup(page); |
4489 | /* |
4490 | * Can be NULL while feeding pages into the page allocator for |
4491 | * the first time, i.e. during boot or memory hotplug; |
4492 | * or when mem_cgroup_disabled(). |
4493 | */ |
4494 | if (likely(pc) && PageCgroupUsed(pc)) |
4495 | return pc; |
4496 | return NULL; |
4497 | } |
4498 | |
4499 | bool mem_cgroup_bad_page_check(struct page *page) |
4500 | { |
4501 | if (mem_cgroup_disabled()) |
4502 | return false; |
4503 | |
4504 | return lookup_page_cgroup_used(page) != NULL; |
4505 | } |
4506 | |
4507 | void mem_cgroup_print_bad_page(struct page *page) |
4508 | { |
4509 | struct page_cgroup *pc; |
4510 | |
4511 | pc = lookup_page_cgroup_used(page); |
4512 | if (pc) { |
4513 | pr_alert("pc:%p pc->flags:%lx pc->mem_cgroup:%p\n", |
4514 | pc, pc->flags, pc->mem_cgroup); |
4515 | } |
4516 | } |
4517 | #endif |
4518 | |
4519 | static int mem_cgroup_resize_limit(struct mem_cgroup *memcg, |
4520 | unsigned long long val) |
4521 | { |
4522 | int retry_count; |
4523 | u64 memswlimit, memlimit; |
4524 | int ret = 0; |
4525 | int children = mem_cgroup_count_children(memcg); |
4526 | u64 curusage, oldusage; |
4527 | int enlarge; |
4528 | |
4529 | /* |
4530 | * For keeping hierarchical_reclaim simple, how long we should retry |
4531 | * is depends on callers. We set our retry-count to be function |
4532 | * of # of children which we should visit in this loop. |
4533 | */ |
4534 | retry_count = MEM_CGROUP_RECLAIM_RETRIES * children; |
4535 | |
4536 | oldusage = res_counter_read_u64(&memcg->res, RES_USAGE); |
4537 | |
4538 | enlarge = 0; |
4539 | while (retry_count) { |
4540 | if (signal_pending(current)) { |
4541 | ret = -EINTR; |
4542 | break; |
4543 | } |
4544 | /* |
4545 | * Rather than hide all in some function, I do this in |
4546 | * open coded manner. You see what this really does. |
4547 | * We have to guarantee memcg->res.limit <= memcg->memsw.limit. |
4548 | */ |
4549 | mutex_lock(&set_limit_mutex); |
4550 | memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT); |
4551 | if (memswlimit < val) { |
4552 | ret = -EINVAL; |
4553 | mutex_unlock(&set_limit_mutex); |
4554 | break; |
4555 | } |
4556 | |
4557 | memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT); |
4558 | if (memlimit < val) |
4559 | enlarge = 1; |
4560 | |
4561 | ret = res_counter_set_limit(&memcg->res, val); |
4562 | if (!ret) { |
4563 | if (memswlimit == val) |
4564 | memcg->memsw_is_minimum = true; |
4565 | else |
4566 | memcg->memsw_is_minimum = false; |
4567 | } |
4568 | mutex_unlock(&set_limit_mutex); |
4569 | |
4570 | if (!ret) |
4571 | break; |
4572 | |
4573 | mem_cgroup_reclaim(memcg, GFP_KERNEL, |
4574 | MEM_CGROUP_RECLAIM_SHRINK); |
4575 | curusage = res_counter_read_u64(&memcg->res, RES_USAGE); |
4576 | /* Usage is reduced ? */ |
4577 | if (curusage >= oldusage) |
4578 | retry_count--; |
4579 | else |
4580 | oldusage = curusage; |
4581 | } |
4582 | if (!ret && enlarge) |
4583 | memcg_oom_recover(memcg); |
4584 | |
4585 | return ret; |
4586 | } |
4587 | |
4588 | static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg, |
4589 | unsigned long long val) |
4590 | { |
4591 | int retry_count; |
4592 | u64 memlimit, memswlimit, oldusage, curusage; |
4593 | int children = mem_cgroup_count_children(memcg); |
4594 | int ret = -EBUSY; |
4595 | int enlarge = 0; |
4596 | |
4597 | /* see mem_cgroup_resize_res_limit */ |
4598 | retry_count = children * MEM_CGROUP_RECLAIM_RETRIES; |
4599 | oldusage = res_counter_read_u64(&memcg->memsw, RES_USAGE); |
4600 | while (retry_count) { |
4601 | if (signal_pending(current)) { |
4602 | ret = -EINTR; |
4603 | break; |
4604 | } |
4605 | /* |
4606 | * Rather than hide all in some function, I do this in |
4607 | * open coded manner. You see what this really does. |
4608 | * We have to guarantee memcg->res.limit <= memcg->memsw.limit. |
4609 | */ |
4610 | mutex_lock(&set_limit_mutex); |
4611 | memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT); |
4612 | if (memlimit > val) { |
4613 | ret = -EINVAL; |
4614 | mutex_unlock(&set_limit_mutex); |
4615 | break; |
4616 | } |
4617 | memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT); |
4618 | if (memswlimit < val) |
4619 | enlarge = 1; |
4620 | ret = res_counter_set_limit(&memcg->memsw, val); |
4621 | if (!ret) { |
4622 | if (memlimit == val) |
4623 | memcg->memsw_is_minimum = true; |
4624 | else |
4625 | memcg->memsw_is_minimum = false; |
4626 | } |
4627 | mutex_unlock(&set_limit_mutex); |
4628 | |
4629 | if (!ret) |
4630 | break; |
4631 | |
4632 | mem_cgroup_reclaim(memcg, GFP_KERNEL, |
4633 | MEM_CGROUP_RECLAIM_NOSWAP | |
4634 | MEM_CGROUP_RECLAIM_SHRINK); |
4635 | curusage = res_counter_read_u64(&memcg->memsw, RES_USAGE); |
4636 | /* Usage is reduced ? */ |
4637 | if (curusage >= oldusage) |
4638 | retry_count--; |
4639 | else |
4640 | oldusage = curusage; |
4641 | } |
4642 | if (!ret && enlarge) |
4643 | memcg_oom_recover(memcg); |
4644 | return ret; |
4645 | } |
4646 | |
4647 | unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order, |
4648 | gfp_t gfp_mask, |
4649 | unsigned long *total_scanned) |
4650 | { |
4651 | unsigned long nr_reclaimed = 0; |
4652 | struct mem_cgroup_per_zone *mz, *next_mz = NULL; |
4653 | unsigned long reclaimed; |
4654 | int loop = 0; |
4655 | struct mem_cgroup_tree_per_zone *mctz; |
4656 | unsigned long long excess; |
4657 | unsigned long nr_scanned; |
4658 | |
4659 | if (order > 0) |
4660 | return 0; |
4661 | |
4662 | mctz = soft_limit_tree_node_zone(zone_to_nid(zone), zone_idx(zone)); |
4663 | /* |
4664 | * This loop can run a while, specially if mem_cgroup's continuously |
4665 | * keep exceeding their soft limit and putting the system under |
4666 | * pressure |
4667 | */ |
4668 | do { |
4669 | if (next_mz) |
4670 | mz = next_mz; |
4671 | else |
4672 | mz = mem_cgroup_largest_soft_limit_node(mctz); |
4673 | if (!mz) |
4674 | break; |
4675 | |
4676 | nr_scanned = 0; |
4677 | reclaimed = mem_cgroup_soft_reclaim(mz->memcg, zone, |
4678 | gfp_mask, &nr_scanned); |
4679 | nr_reclaimed += reclaimed; |
4680 | *total_scanned += nr_scanned; |
4681 | spin_lock(&mctz->lock); |
4682 | |
4683 | /* |
4684 | * If we failed to reclaim anything from this memory cgroup |
4685 | * it is time to move on to the next cgroup |
4686 | */ |
4687 | next_mz = NULL; |
4688 | if (!reclaimed) { |
4689 | do { |
4690 | /* |
4691 | * Loop until we find yet another one. |
4692 | * |
4693 | * By the time we get the soft_limit lock |
4694 | * again, someone might have aded the |
4695 | * group back on the RB tree. Iterate to |
4696 | * make sure we get a different mem. |
4697 | * mem_cgroup_largest_soft_limit_node returns |
4698 | * NULL if no other cgroup is present on |
4699 | * the tree |
4700 | */ |
4701 | next_mz = |
4702 | __mem_cgroup_largest_soft_limit_node(mctz); |
4703 | if (next_mz == mz) |
4704 | css_put(&next_mz->memcg->css); |
4705 | else /* next_mz == NULL or other memcg */ |
4706 | break; |
4707 | } while (1); |
4708 | } |
4709 | __mem_cgroup_remove_exceeded(mz->memcg, mz, mctz); |
4710 | excess = res_counter_soft_limit_excess(&mz->memcg->res); |
4711 | /* |
4712 | * One school of thought says that we should not add |
4713 | * back the node to the tree if reclaim returns 0. |
4714 | * But our reclaim could return 0, simply because due |
4715 | * to priority we are exposing a smaller subset of |
4716 | * memory to reclaim from. Consider this as a longer |
4717 | * term TODO. |
4718 | */ |
4719 | /* If excess == 0, no tree ops */ |
4720 | __mem_cgroup_insert_exceeded(mz->memcg, mz, mctz, excess); |
4721 | spin_unlock(&mctz->lock); |
4722 | css_put(&mz->memcg->css); |
4723 | loop++; |
4724 | /* |
4725 | * Could not reclaim anything and there are no more |
4726 | * mem cgroups to try or we seem to be looping without |
4727 | * reclaiming anything. |
4728 | */ |
4729 | if (!nr_reclaimed && |
4730 | (next_mz == NULL || |
4731 | loop > MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS)) |
4732 | break; |
4733 | } while (!nr_reclaimed); |
4734 | if (next_mz) |
4735 | css_put(&next_mz->memcg->css); |
4736 | return nr_reclaimed; |
4737 | } |
4738 | |
4739 | /** |
4740 | * mem_cgroup_force_empty_list - clears LRU of a group |
4741 | * @memcg: group to clear |
4742 | * @node: NUMA node |
4743 | * @zid: zone id |
4744 | * @lru: lru to to clear |
4745 | * |
4746 | * Traverse a specified page_cgroup list and try to drop them all. This doesn't |
4747 | * reclaim the pages page themselves - pages are moved to the parent (or root) |
4748 | * group. |
4749 | */ |
4750 | static void mem_cgroup_force_empty_list(struct mem_cgroup *memcg, |
4751 | int node, int zid, enum lru_list lru) |
4752 | { |
4753 | struct lruvec *lruvec; |
4754 | unsigned long flags; |
4755 | struct list_head *list; |
4756 | struct page *busy; |
4757 | struct zone *zone; |
4758 | |
4759 | zone = &NODE_DATA(node)->node_zones[zid]; |
4760 | lruvec = mem_cgroup_zone_lruvec(zone, memcg); |
4761 | list = &lruvec->lists[lru]; |
4762 | |
4763 | busy = NULL; |
4764 | do { |
4765 | struct page_cgroup *pc; |
4766 | struct page *page; |
4767 | |
4768 | spin_lock_irqsave(&zone->lru_lock, flags); |
4769 | if (list_empty(list)) { |
4770 | spin_unlock_irqrestore(&zone->lru_lock, flags); |
4771 | break; |
4772 | } |
4773 | page = list_entry(list->prev, struct page, lru); |
4774 | if (busy == page) { |
4775 | list_move(&page->lru, list); |
4776 | busy = NULL; |
4777 | spin_unlock_irqrestore(&zone->lru_lock, flags); |
4778 | continue; |
4779 | } |
4780 | spin_unlock_irqrestore(&zone->lru_lock, flags); |
4781 | |
4782 | pc = lookup_page_cgroup(page); |
4783 | |
4784 | if (mem_cgroup_move_parent(page, pc, memcg)) { |
4785 | /* found lock contention or "pc" is obsolete. */ |
4786 | busy = page; |
4787 | cond_resched(); |
4788 | } else |
4789 | busy = NULL; |
4790 | } while (!list_empty(list)); |
4791 | } |
4792 | |
4793 | /* |
4794 | * make mem_cgroup's charge to be 0 if there is no task by moving |
4795 | * all the charges and pages to the parent. |
4796 | * This enables deleting this mem_cgroup. |
4797 | * |
4798 | * Caller is responsible for holding css reference on the memcg. |
4799 | */ |
4800 | static void mem_cgroup_reparent_charges(struct mem_cgroup *memcg) |
4801 | { |
4802 | int node, zid; |
4803 | u64 usage; |
4804 | |
4805 | do { |
4806 | /* This is for making all *used* pages to be on LRU. */ |
4807 | lru_add_drain_all(); |
4808 | drain_all_stock_sync(memcg); |
4809 | mem_cgroup_start_move(memcg); |
4810 | for_each_node_state(node, N_MEMORY) { |
4811 | for (zid = 0; zid < MAX_NR_ZONES; zid++) { |
4812 | enum lru_list lru; |
4813 | for_each_lru(lru) { |
4814 | mem_cgroup_force_empty_list(memcg, |
4815 | node, zid, lru); |
4816 | } |
4817 | } |
4818 | } |
4819 | mem_cgroup_end_move(memcg); |
4820 | memcg_oom_recover(memcg); |
4821 | cond_resched(); |
4822 | |
4823 | /* |
4824 | * Kernel memory may not necessarily be trackable to a specific |
4825 | * process. So they are not migrated, and therefore we can't |
4826 | * expect their value to drop to 0 here. |
4827 | * Having res filled up with kmem only is enough. |
4828 | * |
4829 | * This is a safety check because mem_cgroup_force_empty_list |
4830 | * could have raced with mem_cgroup_replace_page_cache callers |
4831 | * so the lru seemed empty but the page could have been added |
4832 | * right after the check. RES_USAGE should be safe as we always |
4833 | * charge before adding to the LRU. |
4834 | */ |
4835 | usage = res_counter_read_u64(&memcg->res, RES_USAGE) - |
4836 | res_counter_read_u64(&memcg->kmem, RES_USAGE); |
4837 | } while (usage > 0); |
4838 | } |
4839 | |
4840 | static inline bool memcg_has_children(struct mem_cgroup *memcg) |
4841 | { |
4842 | lockdep_assert_held(&memcg_create_mutex); |
4843 | /* |
4844 | * The lock does not prevent addition or deletion to the list |
4845 | * of children, but it prevents a new child from being |
4846 | * initialized based on this parent in css_online(), so it's |
4847 | * enough to decide whether hierarchically inherited |
4848 | * attributes can still be changed or not. |
4849 | */ |
4850 | return memcg->use_hierarchy && |
4851 | !list_empty(&memcg->css.cgroup->children); |
4852 | } |
4853 | |
4854 | /* |
4855 | * Reclaims as many pages from the given memcg as possible and moves |
4856 | * the rest to the parent. |
4857 | * |
4858 | * Caller is responsible for holding css reference for memcg. |
4859 | */ |
4860 | static int mem_cgroup_force_empty(struct mem_cgroup *memcg) |
4861 | { |
4862 | int nr_retries = MEM_CGROUP_RECLAIM_RETRIES; |
4863 | struct cgroup *cgrp = memcg->css.cgroup; |
4864 | |
4865 | /* returns EBUSY if there is a task or if we come here twice. */ |
4866 | if (cgroup_has_tasks(cgrp) || !list_empty(&cgrp->children)) |
4867 | return -EBUSY; |
4868 | |
4869 | /* we call try-to-free pages for make this cgroup empty */ |
4870 | lru_add_drain_all(); |
4871 | /* try to free all pages in this cgroup */ |
4872 | while (nr_retries && res_counter_read_u64(&memcg->res, RES_USAGE) > 0) { |
4873 | int progress; |
4874 | |
4875 | if (signal_pending(current)) |
4876 | return -EINTR; |
4877 | |
4878 | progress = try_to_free_mem_cgroup_pages(memcg, GFP_KERNEL, |
4879 | false); |
4880 | if (!progress) { |
4881 | nr_retries--; |
4882 | /* maybe some writeback is necessary */ |
4883 | congestion_wait(BLK_RW_ASYNC, HZ/10); |
4884 | } |
4885 | |
4886 | } |
4887 | lru_add_drain(); |
4888 | mem_cgroup_reparent_charges(memcg); |
4889 | |
4890 | return 0; |
4891 | } |
4892 | |
4893 | static int mem_cgroup_force_empty_write(struct cgroup_subsys_state *css, |
4894 | unsigned int event) |
4895 | { |
4896 | struct mem_cgroup *memcg = mem_cgroup_from_css(css); |
4897 | |
4898 | if (mem_cgroup_is_root(memcg)) |
4899 | return -EINVAL; |
4900 | return mem_cgroup_force_empty(memcg); |
4901 | } |
4902 | |
4903 | static u64 mem_cgroup_hierarchy_read(struct cgroup_subsys_state *css, |
4904 | struct cftype *cft) |
4905 | { |
4906 | return mem_cgroup_from_css(css)->use_hierarchy; |
4907 | } |
4908 | |
4909 | static int mem_cgroup_hierarchy_write(struct cgroup_subsys_state *css, |
4910 | struct cftype *cft, u64 val) |
4911 | { |
4912 | int retval = 0; |
4913 | struct mem_cgroup *memcg = mem_cgroup_from_css(css); |
4914 | struct mem_cgroup *parent_memcg = mem_cgroup_from_css(css_parent(&memcg->css)); |
4915 | |
4916 | mutex_lock(&memcg_create_mutex); |
4917 | |
4918 | if (memcg->use_hierarchy == val) |
4919 | goto out; |
4920 | |
4921 | /* |
4922 | * If parent's use_hierarchy is set, we can't make any modifications |
4923 | * in the child subtrees. If it is unset, then the change can |
4924 | * occur, provided the current cgroup has no children. |
4925 | * |
4926 | * For the root cgroup, parent_mem is NULL, we allow value to be |
4927 | * set if there are no children. |
4928 | */ |
4929 | if ((!parent_memcg || !parent_memcg->use_hierarchy) && |
4930 | (val == 1 || val == 0)) { |
4931 | if (list_empty(&memcg->css.cgroup->children)) |
4932 | memcg->use_hierarchy = val; |
4933 | else |
4934 | retval = -EBUSY; |
4935 | } else |
4936 | retval = -EINVAL; |
4937 | |
4938 | out: |
4939 | mutex_unlock(&memcg_create_mutex); |
4940 | |
4941 | return retval; |
4942 | } |
4943 | |
4944 | |
4945 | static unsigned long mem_cgroup_recursive_stat(struct mem_cgroup *memcg, |
4946 | enum mem_cgroup_stat_index idx) |
4947 | { |
4948 | struct mem_cgroup *iter; |
4949 | long val = 0; |
4950 | |
4951 | /* Per-cpu values can be negative, use a signed accumulator */ |
4952 | for_each_mem_cgroup_tree(iter, memcg) |
4953 | val += mem_cgroup_read_stat(iter, idx); |
4954 | |
4955 | if (val < 0) /* race ? */ |
4956 | val = 0; |
4957 | return val; |
4958 | } |
4959 | |
4960 | static inline u64 mem_cgroup_usage(struct mem_cgroup *memcg, bool swap) |
4961 | { |
4962 | u64 val; |
4963 | |
4964 | if (!mem_cgroup_is_root(memcg)) { |
4965 | if (!swap) |
4966 | return res_counter_read_u64(&memcg->res, RES_USAGE); |
4967 | else |
4968 | return res_counter_read_u64(&memcg->memsw, RES_USAGE); |
4969 | } |
4970 | |
4971 | /* |
4972 | * Transparent hugepages are still accounted for in MEM_CGROUP_STAT_RSS |
4973 | * as well as in MEM_CGROUP_STAT_RSS_HUGE. |
4974 | */ |
4975 | val = mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_CACHE); |
4976 | val += mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_RSS); |
4977 | |
4978 | if (swap) |
4979 | val += mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_SWAP); |
4980 | |
4981 | return val << PAGE_SHIFT; |
4982 | } |
4983 | |
4984 | static u64 mem_cgroup_read_u64(struct cgroup_subsys_state *css, |
4985 | struct cftype *cft) |
4986 | { |
4987 | struct mem_cgroup *memcg = mem_cgroup_from_css(css); |
4988 | u64 val; |
4989 | int name; |
4990 | enum res_type type; |
4991 | |
4992 | type = MEMFILE_TYPE(cft->private); |
4993 | name = MEMFILE_ATTR(cft->private); |
4994 | |
4995 | switch (type) { |
4996 | case _MEM: |
4997 | if (name == RES_USAGE) |
4998 | val = mem_cgroup_usage(memcg, false); |
4999 | else |
5000 | val = res_counter_read_u64(&memcg->res, name); |
5001 | break; |
5002 | case _MEMSWAP: |
5003 | if (name == RES_USAGE) |
5004 | val = mem_cgroup_usage(memcg, true); |
5005 | else |
5006 | val = res_counter_read_u64(&memcg->memsw, name); |
5007 | break; |
5008 | case _KMEM: |
5009 | val = res_counter_read_u64(&memcg->kmem, name); |
5010 | break; |
5011 | default: |
5012 | BUG(); |
5013 | } |
5014 | |
5015 | return val; |
5016 | } |
5017 | |
5018 | #ifdef CONFIG_MEMCG_KMEM |
5019 | /* should be called with activate_kmem_mutex held */ |
5020 | static int __memcg_activate_kmem(struct mem_cgroup *memcg, |
5021 | unsigned long long limit) |
5022 | { |
5023 | int err = 0; |
5024 | int memcg_id; |
5025 | |
5026 | if (memcg_kmem_is_active(memcg)) |
5027 | return 0; |
5028 | |
5029 | /* |
5030 | * We are going to allocate memory for data shared by all memory |
5031 | * cgroups so let's stop accounting here. |
5032 | */ |
5033 | memcg_stop_kmem_account(); |
5034 | |
5035 | /* |
5036 | * For simplicity, we won't allow this to be disabled. It also can't |
5037 | * be changed if the cgroup has children already, or if tasks had |
5038 | * already joined. |
5039 | * |
5040 | * If tasks join before we set the limit, a person looking at |
5041 | * kmem.usage_in_bytes will have no way to determine when it took |
5042 | * place, which makes the value quite meaningless. |
5043 | * |
5044 | * After it first became limited, changes in the value of the limit are |
5045 | * of course permitted. |
5046 | */ |
5047 | mutex_lock(&memcg_create_mutex); |
5048 | if (cgroup_has_tasks(memcg->css.cgroup) || memcg_has_children(memcg)) |
5049 | err = -EBUSY; |
5050 | mutex_unlock(&memcg_create_mutex); |
5051 | if (err) |
5052 | goto out; |
5053 | |
5054 | memcg_id = ida_simple_get(&kmem_limited_groups, |
5055 | 0, MEMCG_CACHES_MAX_SIZE, GFP_KERNEL); |
5056 | if (memcg_id < 0) { |
5057 | err = memcg_id; |
5058 | goto out; |
5059 | } |
5060 | |
5061 | /* |
5062 | * Make sure we have enough space for this cgroup in each root cache's |
5063 | * memcg_params. |
5064 | */ |
5065 | err = memcg_update_all_caches(memcg_id + 1); |
5066 | if (err) |
5067 | goto out_rmid; |
5068 | |
5069 | memcg->kmemcg_id = memcg_id; |
5070 | INIT_LIST_HEAD(&memcg->memcg_slab_caches); |
5071 | mutex_init(&memcg->slab_caches_mutex); |
5072 | |
5073 | /* |
5074 | * We couldn't have accounted to this cgroup, because it hasn't got the |
5075 | * active bit set yet, so this should succeed. |
5076 | */ |
5077 | err = res_counter_set_limit(&memcg->kmem, limit); |
5078 | VM_BUG_ON(err); |
5079 | |
5080 | static_key_slow_inc(&memcg_kmem_enabled_key); |
5081 | /* |
5082 | * Setting the active bit after enabling static branching will |
5083 | * guarantee no one starts accounting before all call sites are |
5084 | * patched. |
5085 | */ |
5086 | memcg_kmem_set_active(memcg); |
5087 | out: |
5088 | memcg_resume_kmem_account(); |
5089 | return err; |
5090 | |
5091 | out_rmid: |
5092 | ida_simple_remove(&kmem_limited_groups, memcg_id); |
5093 | goto out; |
5094 | } |
5095 | |
5096 | static int memcg_activate_kmem(struct mem_cgroup *memcg, |
5097 | unsigned long long limit) |
5098 | { |
5099 | int ret; |
5100 | |
5101 | mutex_lock(&activate_kmem_mutex); |
5102 | ret = __memcg_activate_kmem(memcg, limit); |
5103 | mutex_unlock(&activate_kmem_mutex); |
5104 | return ret; |
5105 | } |
5106 | |
5107 | static int memcg_update_kmem_limit(struct mem_cgroup *memcg, |
5108 | unsigned long long val) |
5109 | { |
5110 | int ret; |
5111 | |
5112 | if (!memcg_kmem_is_active(memcg)) |
5113 | ret = memcg_activate_kmem(memcg, val); |
5114 | else |
5115 | ret = res_counter_set_limit(&memcg->kmem, val); |
5116 | return ret; |
5117 | } |
5118 | |
5119 | static int memcg_propagate_kmem(struct mem_cgroup *memcg) |
5120 | { |
5121 | int ret = 0; |
5122 | struct mem_cgroup *parent = parent_mem_cgroup(memcg); |
5123 | |
5124 | if (!parent) |
5125 | return 0; |
5126 | |
5127 | mutex_lock(&activate_kmem_mutex); |
5128 | /* |
5129 | * If the parent cgroup is not kmem-active now, it cannot be activated |
5130 | * after this point, because it has at least one child already. |
5131 | */ |
5132 | if (memcg_kmem_is_active(parent)) |
5133 | ret = __memcg_activate_kmem(memcg, RES_COUNTER_MAX); |
5134 | mutex_unlock(&activate_kmem_mutex); |
5135 | return ret; |
5136 | } |
5137 | #else |
5138 | static int memcg_update_kmem_limit(struct mem_cgroup *memcg, |
5139 | unsigned long long val) |
5140 | { |
5141 | return -EINVAL; |
5142 | } |
5143 | #endif /* CONFIG_MEMCG_KMEM */ |
5144 | |
5145 | /* |
5146 | * The user of this function is... |
5147 | * RES_LIMIT. |
5148 | */ |
5149 | static int mem_cgroup_write(struct cgroup_subsys_state *css, struct cftype *cft, |
5150 | char *buffer) |
5151 | { |
5152 | struct mem_cgroup *memcg = mem_cgroup_from_css(css); |
5153 | enum res_type type; |
5154 | int name; |
5155 | unsigned long long val; |
5156 | int ret; |
5157 | |
5158 | type = MEMFILE_TYPE(cft->private); |
5159 | name = MEMFILE_ATTR(cft->private); |
5160 | |
5161 | switch (name) { |
5162 | case RES_LIMIT: |
5163 | if (mem_cgroup_is_root(memcg)) { /* Can't set limit on root */ |
5164 | ret = -EINVAL; |
5165 | break; |
5166 | } |
5167 | /* This function does all necessary parse...reuse it */ |
5168 | ret = res_counter_memparse_write_strategy(buffer, &val); |
5169 | if (ret) |
5170 | break; |
5171 | if (type == _MEM) |
5172 | ret = mem_cgroup_resize_limit(memcg, val); |
5173 | else if (type == _MEMSWAP) |
5174 | ret = mem_cgroup_resize_memsw_limit(memcg, val); |
5175 | else if (type == _KMEM) |
5176 | ret = memcg_update_kmem_limit(memcg, val); |
5177 | else |
5178 | return -EINVAL; |
5179 | break; |
5180 | case RES_SOFT_LIMIT: |
5181 | ret = res_counter_memparse_write_strategy(buffer, &val); |
5182 | if (ret) |
5183 | break; |
5184 | /* |
5185 | * For memsw, soft limits are hard to implement in terms |
5186 | * of semantics, for now, we support soft limits for |
5187 | * control without swap |
5188 | */ |
5189 | if (type == _MEM) |
5190 | ret = res_counter_set_soft_limit(&memcg->res, val); |
5191 | else |
5192 | ret = -EINVAL; |
5193 | break; |
5194 | default: |
5195 | ret = -EINVAL; /* should be BUG() ? */ |
5196 | break; |
5197 | } |
5198 | return ret; |
5199 | } |
5200 | |
5201 | static void memcg_get_hierarchical_limit(struct mem_cgroup *memcg, |
5202 | unsigned long long *mem_limit, unsigned long long *memsw_limit) |
5203 | { |
5204 | unsigned long long min_limit, min_memsw_limit, tmp; |
5205 | |
5206 | min_limit = res_counter_read_u64(&memcg->res, RES_LIMIT); |
5207 | min_memsw_limit = res_counter_read_u64(&memcg->memsw, RES_LIMIT); |
5208 | if (!memcg->use_hierarchy) |
5209 | goto out; |
5210 | |
5211 | while (css_parent(&memcg->css)) { |
5212 | memcg = mem_cgroup_from_css(css_parent(&memcg->css)); |
5213 | if (!memcg->use_hierarchy) |
5214 | break; |
5215 | tmp = res_counter_read_u64(&memcg->res, RES_LIMIT); |
5216 | min_limit = min(min_limit, tmp); |
5217 | tmp = res_counter_read_u64(&memcg->memsw, RES_LIMIT); |
5218 | min_memsw_limit = min(min_memsw_limit, tmp); |
5219 | } |
5220 | out: |
5221 | *mem_limit = min_limit; |
5222 | *memsw_limit = min_memsw_limit; |
5223 | } |
5224 | |
5225 | static int mem_cgroup_reset(struct cgroup_subsys_state *css, unsigned int event) |
5226 | { |
5227 | struct mem_cgroup *memcg = mem_cgroup_from_css(css); |
5228 | int name; |
5229 | enum res_type type; |
5230 | |
5231 | type = MEMFILE_TYPE(event); |
5232 | name = MEMFILE_ATTR(event); |
5233 | |
5234 | switch (name) { |
5235 | case RES_MAX_USAGE: |
5236 | if (type == _MEM) |
5237 | res_counter_reset_max(&memcg->res); |
5238 | else if (type == _MEMSWAP) |
5239 | res_counter_reset_max(&memcg->memsw); |
5240 | else if (type == _KMEM) |
5241 | res_counter_reset_max(&memcg->kmem); |
5242 | else |
5243 | return -EINVAL; |
5244 | break; |
5245 | case RES_FAILCNT: |
5246 | if (type == _MEM) |
5247 | res_counter_reset_failcnt(&memcg->res); |
5248 | else if (type == _MEMSWAP) |
5249 | res_counter_reset_failcnt(&memcg->memsw); |
5250 | else if (type == _KMEM) |
5251 | res_counter_reset_failcnt(&memcg->kmem); |
5252 | else |
5253 | return -EINVAL; |
5254 | break; |
5255 | } |
5256 | |
5257 | return 0; |
5258 | } |
5259 | |
5260 | static u64 mem_cgroup_move_charge_read(struct cgroup_subsys_state *css, |
5261 | struct cftype *cft) |
5262 | { |
5263 | return mem_cgroup_from_css(css)->move_charge_at_immigrate; |
5264 | } |
5265 | |
5266 | #ifdef CONFIG_MMU |
5267 | static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css, |
5268 | struct cftype *cft, u64 val) |
5269 | { |
5270 | struct mem_cgroup *memcg = mem_cgroup_from_css(css); |
5271 | |
5272 | if (val >= (1 << NR_MOVE_TYPE)) |
5273 | return -EINVAL; |
5274 | |
5275 | /* |
5276 | * No kind of locking is needed in here, because ->can_attach() will |
5277 | * check this value once in the beginning of the process, and then carry |
5278 | * on with stale data. This means that changes to this value will only |
5279 | * affect task migrations starting after the change. |
5280 | */ |
5281 | memcg->move_charge_at_immigrate = val; |
5282 | return 0; |
5283 | } |
5284 | #else |
5285 | static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css, |
5286 | struct cftype *cft, u64 val) |
5287 | { |
5288 | return -ENOSYS; |
5289 | } |
5290 | #endif |
5291 | |
5292 | #ifdef CONFIG_NUMA |
5293 | static int memcg_numa_stat_show(struct seq_file *m, void *v) |
5294 | { |
5295 | struct numa_stat { |
5296 | const char *name; |
5297 | unsigned int lru_mask; |
5298 | }; |
5299 | |
5300 | static const struct numa_stat stats[] = { |
5301 | { "total", LRU_ALL }, |
5302 | { "file", LRU_ALL_FILE }, |
5303 | { "anon", LRU_ALL_ANON }, |
5304 | { "unevictable", BIT(LRU_UNEVICTABLE) }, |
5305 | }; |
5306 | const struct numa_stat *stat; |
5307 | int nid; |
5308 | unsigned long nr; |
5309 | struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m)); |
5310 | |
5311 | for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) { |
5312 | nr = mem_cgroup_nr_lru_pages(memcg, stat->lru_mask); |
5313 | seq_printf(m, "%s=%lu", stat->name, nr); |
5314 | for_each_node_state(nid, N_MEMORY) { |
5315 | nr = mem_cgroup_node_nr_lru_pages(memcg, nid, |
5316 | stat->lru_mask); |
5317 | seq_printf(m, " N%d=%lu", nid, nr); |
5318 | } |
5319 | seq_putc(m, '\n'); |
5320 | } |
5321 | |
5322 | for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) { |
5323 | struct mem_cgroup *iter; |
5324 | |
5325 | nr = 0; |
5326 | for_each_mem_cgroup_tree(iter, memcg) |
5327 | nr += mem_cgroup_nr_lru_pages(iter, stat->lru_mask); |
5328 | seq_printf(m, "hierarchical_%s=%lu", stat->name, nr); |
5329 | for_each_node_state(nid, N_MEMORY) { |
5330 | nr = 0; |
5331 | for_each_mem_cgroup_tree(iter, memcg) |
5332 | nr += mem_cgroup_node_nr_lru_pages( |
5333 | iter, nid, stat->lru_mask); |
5334 | seq_printf(m, " N%d=%lu", nid, nr); |
5335 | } |
5336 | seq_putc(m, '\n'); |
5337 | } |
5338 | |
5339 | return 0; |
5340 | } |
5341 | #endif /* CONFIG_NUMA */ |
5342 | |
5343 | static inline void mem_cgroup_lru_names_not_uptodate(void) |
5344 | { |
5345 | BUILD_BUG_ON(ARRAY_SIZE(mem_cgroup_lru_names) != NR_LRU_LISTS); |
5346 | } |
5347 | |
5348 | static int memcg_stat_show(struct seq_file *m, void *v) |
5349 | { |
5350 | struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m)); |
5351 | struct mem_cgroup *mi; |
5352 | unsigned int i; |
5353 | |
5354 | for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) { |
5355 | if (i == MEM_CGROUP_STAT_SWAP && !do_swap_account) |
5356 | continue; |
5357 | seq_printf(m, "%s %ld\n", mem_cgroup_stat_names[i], |
5358 | mem_cgroup_read_stat(memcg, i) * PAGE_SIZE); |
5359 | } |
5360 | |
5361 | for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++) |
5362 | seq_printf(m, "%s %lu\n", mem_cgroup_events_names[i], |
5363 | mem_cgroup_read_events(memcg, i)); |
5364 | |
5365 | for (i = 0; i < NR_LRU_LISTS; i++) |
5366 | seq_printf(m, "%s %lu\n", mem_cgroup_lru_names[i], |
5367 | mem_cgroup_nr_lru_pages(memcg, BIT(i)) * PAGE_SIZE); |
5368 | |
5369 | /* Hierarchical information */ |
5370 | { |
5371 | unsigned long long limit, memsw_limit; |
5372 | memcg_get_hierarchical_limit(memcg, &limit, &memsw_limit); |
5373 | seq_printf(m, "hierarchical_memory_limit %llu\n", limit); |
5374 | if (do_swap_account) |
5375 | seq_printf(m, "hierarchical_memsw_limit %llu\n", |
5376 | memsw_limit); |
5377 | } |
5378 | |
5379 | for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) { |
5380 | long long val = 0; |
5381 | |
5382 | if (i == MEM_CGROUP_STAT_SWAP && !do_swap_account) |
5383 | continue; |
5384 | for_each_mem_cgroup_tree(mi, memcg) |
5385 | val += mem_cgroup_read_stat(mi, i) * PAGE_SIZE; |
5386 | seq_printf(m, "total_%s %lld\n", mem_cgroup_stat_names[i], val); |
5387 | } |
5388 | |
5389 | for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++) { |
5390 | unsigned long long val = 0; |
5391 | |
5392 | for_each_mem_cgroup_tree(mi, memcg) |
5393 | val += mem_cgroup_read_events(mi, i); |
5394 | seq_printf(m, "total_%s %llu\n", |
5395 | mem_cgroup_events_names[i], val); |
5396 | } |
5397 | |
5398 | for (i = 0; i < NR_LRU_LISTS; i++) { |
5399 | unsigned long long val = 0; |
5400 | |
5401 | for_each_mem_cgroup_tree(mi, memcg) |
5402 | val += mem_cgroup_nr_lru_pages(mi, BIT(i)) * PAGE_SIZE; |
5403 | seq_printf(m, "total_%s %llu\n", mem_cgroup_lru_names[i], val); |
5404 | } |
5405 | |
5406 | #ifdef CONFIG_DEBUG_VM |
5407 | { |
5408 | int nid, zid; |
5409 | struct mem_cgroup_per_zone *mz; |
5410 | struct zone_reclaim_stat *rstat; |
5411 | unsigned long recent_rotated[2] = {0, 0}; |
5412 | unsigned long recent_scanned[2] = {0, 0}; |
5413 | |
5414 | for_each_online_node(nid) |
5415 | for (zid = 0; zid < MAX_NR_ZONES; zid++) { |
5416 | mz = mem_cgroup_zoneinfo(memcg, nid, zid); |
5417 | rstat = &mz->lruvec.reclaim_stat; |
5418 | |
5419 | recent_rotated[0] += rstat->recent_rotated[0]; |
5420 | recent_rotated[1] += rstat->recent_rotated[1]; |
5421 | recent_scanned[0] += rstat->recent_scanned[0]; |
5422 | recent_scanned[1] += rstat->recent_scanned[1]; |
5423 | } |
5424 | seq_printf(m, "recent_rotated_anon %lu\n", recent_rotated[0]); |
5425 | seq_printf(m, "recent_rotated_file %lu\n", recent_rotated[1]); |
5426 | seq_printf(m, "recent_scanned_anon %lu\n", recent_scanned[0]); |
5427 | seq_printf(m, "recent_scanned_file %lu\n", recent_scanned[1]); |
5428 | } |
5429 | #endif |
5430 | |
5431 | return 0; |
5432 | } |
5433 | |
5434 | static u64 mem_cgroup_swappiness_read(struct cgroup_subsys_state *css, |
5435 | struct cftype *cft) |
5436 | { |
5437 | struct mem_cgroup *memcg = mem_cgroup_from_css(css); |
5438 | |
5439 | return mem_cgroup_swappiness(memcg); |
5440 | } |
5441 | |
5442 | static int mem_cgroup_swappiness_write(struct cgroup_subsys_state *css, |
5443 | struct cftype *cft, u64 val) |
5444 | { |
5445 | struct mem_cgroup *memcg = mem_cgroup_from_css(css); |
5446 | struct mem_cgroup *parent = mem_cgroup_from_css(css_parent(&memcg->css)); |
5447 | |
5448 | if (val > 100 || !parent) |
5449 | return -EINVAL; |
5450 | |
5451 | mutex_lock(&memcg_create_mutex); |
5452 | |
5453 | /* If under hierarchy, only empty-root can set this value */ |
5454 | if ((parent->use_hierarchy) || memcg_has_children(memcg)) { |
5455 | mutex_unlock(&memcg_create_mutex); |
5456 | return -EINVAL; |
5457 | } |
5458 | |
5459 | memcg->swappiness = val; |
5460 | |
5461 | mutex_unlock(&memcg_create_mutex); |
5462 | |
5463 | return 0; |
5464 | } |
5465 | |
5466 | static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap) |
5467 | { |
5468 | struct mem_cgroup_threshold_ary *t; |
5469 | u64 usage; |
5470 | int i; |
5471 | |
5472 | rcu_read_lock(); |
5473 | if (!swap) |
5474 | t = rcu_dereference(memcg->thresholds.primary); |
5475 | else |
5476 | t = rcu_dereference(memcg->memsw_thresholds.primary); |
5477 | |
5478 | if (!t) |
5479 | goto unlock; |
5480 | |
5481 | usage = mem_cgroup_usage(memcg, swap); |
5482 | |
5483 | /* |
5484 | * current_threshold points to threshold just below or equal to usage. |
5485 | * If it's not true, a threshold was crossed after last |
5486 | * call of __mem_cgroup_threshold(). |
5487 | */ |
5488 | i = t->current_threshold; |
5489 | |
5490 | /* |
5491 | * Iterate backward over array of thresholds starting from |
5492 | * current_threshold and check if a threshold is crossed. |
5493 | * If none of thresholds below usage is crossed, we read |
5494 | * only one element of the array here. |
5495 | */ |
5496 | for (; i >= 0 && unlikely(t->entries[i].threshold > usage); i--) |
5497 | eventfd_signal(t->entries[i].eventfd, 1); |
5498 | |
5499 | /* i = current_threshold + 1 */ |
5500 | i++; |
5501 | |
5502 | /* |
5503 | * Iterate forward over array of thresholds starting from |
5504 | * current_threshold+1 and check if a threshold is crossed. |
5505 | * If none of thresholds above usage is crossed, we read |
5506 | * only one element of the array here. |
5507 | */ |
5508 | for (; i < t->size && unlikely(t->entries[i].threshold <= usage); i++) |
5509 | eventfd_signal(t->entries[i].eventfd, 1); |
5510 | |
5511 | /* Update current_threshold */ |
5512 | t->current_threshold = i - 1; |
5513 | unlock: |
5514 | rcu_read_unlock(); |
5515 | } |
5516 | |
5517 | static void mem_cgroup_threshold(struct mem_cgroup *memcg) |
5518 | { |
5519 | while (memcg) { |
5520 | __mem_cgroup_threshold(memcg, false); |
5521 | if (do_swap_account) |
5522 | __mem_cgroup_threshold(memcg, true); |
5523 | |
5524 | memcg = parent_mem_cgroup(memcg); |
5525 | } |
5526 | } |
5527 | |
5528 | static int compare_thresholds(const void *a, const void *b) |
5529 | { |
5530 | const struct mem_cgroup_threshold *_a = a; |
5531 | const struct mem_cgroup_threshold *_b = b; |
5532 | |
5533 | if (_a->threshold > _b->threshold) |
5534 | return 1; |
5535 | |
5536 | if (_a->threshold < _b->threshold) |
5537 | return -1; |
5538 | |
5539 | return 0; |
5540 | } |
5541 | |
5542 | static int mem_cgroup_oom_notify_cb(struct mem_cgroup *memcg) |
5543 | { |
5544 | struct mem_cgroup_eventfd_list *ev; |
5545 | |
5546 | list_for_each_entry(ev, &memcg->oom_notify, list) |
5547 | eventfd_signal(ev->eventfd, 1); |
5548 | return 0; |
5549 | } |
5550 | |
5551 | static void mem_cgroup_oom_notify(struct mem_cgroup *memcg) |
5552 | { |
5553 | struct mem_cgroup *iter; |
5554 | |
5555 | for_each_mem_cgroup_tree(iter, memcg) |
5556 | mem_cgroup_oom_notify_cb(iter); |
5557 | } |
5558 | |
5559 | static int __mem_cgroup_usage_register_event(struct mem_cgroup *memcg, |
5560 | struct eventfd_ctx *eventfd, const char *args, enum res_type type) |
5561 | { |
5562 | struct mem_cgroup_thresholds *thresholds; |
5563 | struct mem_cgroup_threshold_ary *new; |
5564 | u64 threshold, usage; |
5565 | int i, size, ret; |
5566 | |
5567 | ret = res_counter_memparse_write_strategy(args, &threshold); |
5568 | if (ret) |
5569 | return ret; |
5570 | |
5571 | mutex_lock(&memcg->thresholds_lock); |
5572 | |
5573 | if (type == _MEM) |
5574 | thresholds = &memcg->thresholds; |
5575 | else if (type == _MEMSWAP) |
5576 | thresholds = &memcg->memsw_thresholds; |
5577 | else |
5578 | BUG(); |
5579 | |
5580 | usage = mem_cgroup_usage(memcg, type == _MEMSWAP); |
5581 | |
5582 | /* Check if a threshold crossed before adding a new one */ |
5583 | if (thresholds->primary) |
5584 | __mem_cgroup_threshold(memcg, type == _MEMSWAP); |
5585 | |
5586 | size = thresholds->primary ? thresholds->primary->size + 1 : 1; |
5587 | |
5588 | /* Allocate memory for new array of thresholds */ |
5589 | new = kmalloc(sizeof(*new) + size * sizeof(struct mem_cgroup_threshold), |
5590 | GFP_KERNEL); |
5591 | if (!new) { |
5592 | ret = -ENOMEM; |
5593 | goto unlock; |
5594 | } |
5595 | new->size = size; |
5596 | |
5597 | /* Copy thresholds (if any) to new array */ |
5598 | if (thresholds->primary) { |
5599 | memcpy(new->entries, thresholds->primary->entries, (size - 1) * |
5600 | sizeof(struct mem_cgroup_threshold)); |
5601 | } |
5602 | |
5603 | /* Add new threshold */ |
5604 | new->entries[size - 1].eventfd = eventfd; |
5605 | new->entries[size - 1].threshold = threshold; |
5606 | |
5607 | /* Sort thresholds. Registering of new threshold isn't time-critical */ |
5608 | sort(new->entries, size, sizeof(struct mem_cgroup_threshold), |
5609 | compare_thresholds, NULL); |
5610 | |
5611 | /* Find current threshold */ |
5612 | new->current_threshold = -1; |
5613 | for (i = 0; i < size; i++) { |
5614 | if (new->entries[i].threshold <= usage) { |
5615 | /* |
5616 | * new->current_threshold will not be used until |
5617 | * rcu_assign_pointer(), so it's safe to increment |
5618 | * it here. |
5619 | */ |
5620 | ++new->current_threshold; |
5621 | } else |
5622 | break; |
5623 | } |
5624 | |
5625 | /* Free old spare buffer and save old primary buffer as spare */ |
5626 | kfree(thresholds->spare); |
5627 | thresholds->spare = thresholds->primary; |
5628 | |
5629 | rcu_assign_pointer(thresholds->primary, new); |
5630 | |
5631 | /* To be sure that nobody uses thresholds */ |
5632 | synchronize_rcu(); |
5633 | |
5634 | unlock: |
5635 | mutex_unlock(&memcg->thresholds_lock); |
5636 | |
5637 | return ret; |
5638 | } |
5639 | |
5640 | static int mem_cgroup_usage_register_event(struct mem_cgroup *memcg, |
5641 | struct eventfd_ctx *eventfd, const char *args) |
5642 | { |
5643 | return __mem_cgroup_usage_register_event(memcg, eventfd, args, _MEM); |
5644 | } |
5645 | |
5646 | static int memsw_cgroup_usage_register_event(struct mem_cgroup *memcg, |
5647 | struct eventfd_ctx *eventfd, const char *args) |
5648 | { |
5649 | return __mem_cgroup_usage_register_event(memcg, eventfd, args, _MEMSWAP); |
5650 | } |
5651 | |
5652 | static void __mem_cgroup_usage_unregister_event(struct mem_cgroup *memcg, |
5653 | struct eventfd_ctx *eventfd, enum res_type type) |
5654 | { |
5655 | struct mem_cgroup_thresholds *thresholds; |
5656 | struct mem_cgroup_threshold_ary *new; |
5657 | u64 usage; |
5658 | int i, j, size; |
5659 | |
5660 | mutex_lock(&memcg->thresholds_lock); |
5661 | if (type == _MEM) |
5662 | thresholds = &memcg->thresholds; |
5663 | else if (type == _MEMSWAP) |
5664 | thresholds = &memcg->memsw_thresholds; |
5665 | else |
5666 | BUG(); |
5667 | |
5668 | if (!thresholds->primary) |
5669 | goto unlock; |
5670 | |
5671 | usage = mem_cgroup_usage(memcg, type == _MEMSWAP); |
5672 | |
5673 | /* Check if a threshold crossed before removing */ |
5674 | __mem_cgroup_threshold(memcg, type == _MEMSWAP); |
5675 | |
5676 | /* Calculate new number of threshold */ |
5677 | size = 0; |
5678 | for (i = 0; i < thresholds->primary->size; i++) { |
5679 | if (thresholds->primary->entries[i].eventfd != eventfd) |
5680 | size++; |
5681 | } |
5682 | |
5683 | new = thresholds->spare; |
5684 | |
5685 | /* Set thresholds array to NULL if we don't have thresholds */ |
5686 | if (!size) { |
5687 | kfree(new); |
5688 | new = NULL; |
5689 | goto swap_buffers; |
5690 | } |
5691 | |
5692 | new->size = size; |
5693 | |
5694 | /* Copy thresholds and find current threshold */ |
5695 | new->current_threshold = -1; |
5696 | for (i = 0, j = 0; i < thresholds->primary->size; i++) { |
5697 | if (thresholds->primary->entries[i].eventfd == eventfd) |
5698 | continue; |
5699 | |
5700 | new->entries[j] = thresholds->primary->entries[i]; |
5701 | if (new->entries[j].threshold <= usage) { |
5702 | /* |
5703 | * new->current_threshold will not be used |
5704 | * until rcu_assign_pointer(), so it's safe to increment |
5705 | * it here. |
5706 | */ |
5707 | ++new->current_threshold; |
5708 | } |
5709 | j++; |
5710 | } |
5711 | |
5712 | swap_buffers: |
5713 | /* Swap primary and spare array */ |
5714 | thresholds->spare = thresholds->primary; |
5715 | /* If all events are unregistered, free the spare array */ |
5716 | if (!new) { |
5717 | kfree(thresholds->spare); |
5718 | thresholds->spare = NULL; |
5719 | } |
5720 | |
5721 | rcu_assign_pointer(thresholds->primary, new); |
5722 | |
5723 | /* To be sure that nobody uses thresholds */ |
5724 | synchronize_rcu(); |
5725 | unlock: |
5726 | mutex_unlock(&memcg->thresholds_lock); |
5727 | } |
5728 | |
5729 | static void mem_cgroup_usage_unregister_event(struct mem_cgroup *memcg, |
5730 | struct eventfd_ctx *eventfd) |
5731 | { |
5732 | return __mem_cgroup_usage_unregister_event(memcg, eventfd, _MEM); |
5733 | } |
5734 | |
5735 | static void memsw_cgroup_usage_unregister_event(struct mem_cgroup *memcg, |
5736 | struct eventfd_ctx *eventfd) |
5737 | { |
5738 | return __mem_cgroup_usage_unregister_event(memcg, eventfd, _MEMSWAP); |
5739 | } |
5740 | |
5741 | static int mem_cgroup_oom_register_event(struct mem_cgroup *memcg, |
5742 | struct eventfd_ctx *eventfd, const char *args) |
5743 | { |
5744 | struct mem_cgroup_eventfd_list *event; |
5745 | |
5746 | event = kmalloc(sizeof(*event), GFP_KERNEL); |
5747 | if (!event) |
5748 | return -ENOMEM; |
5749 | |
5750 | spin_lock(&memcg_oom_lock); |
5751 | |
5752 | event->eventfd = eventfd; |
5753 | list_add(&event->list, &memcg->oom_notify); |
5754 | |
5755 | /* already in OOM ? */ |
5756 | if (atomic_read(&memcg->under_oom)) |
5757 | eventfd_signal(eventfd, 1); |
5758 | spin_unlock(&memcg_oom_lock); |
5759 | |
5760 | return 0; |
5761 | } |
5762 | |
5763 | static void mem_cgroup_oom_unregister_event(struct mem_cgroup *memcg, |
5764 | struct eventfd_ctx *eventfd) |
5765 | { |
5766 | struct mem_cgroup_eventfd_list *ev, *tmp; |
5767 | |
5768 | spin_lock(&memcg_oom_lock); |
5769 | |
5770 | list_for_each_entry_safe(ev, tmp, &memcg->oom_notify, list) { |
5771 | if (ev->eventfd == eventfd) { |
5772 | list_del(&ev->list); |
5773 | kfree(ev); |
5774 | } |
5775 | } |
5776 | |
5777 | spin_unlock(&memcg_oom_lock); |
5778 | } |
5779 | |
5780 | static int mem_cgroup_oom_control_read(struct seq_file *sf, void *v) |
5781 | { |
5782 | struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(sf)); |
5783 | |
5784 | seq_printf(sf, "oom_kill_disable %d\n", memcg->oom_kill_disable); |
5785 | seq_printf(sf, "under_oom %d\n", (bool)atomic_read(&memcg->under_oom)); |
5786 | return 0; |
5787 | } |
5788 | |
5789 | static int mem_cgroup_oom_control_write(struct cgroup_subsys_state *css, |
5790 | struct cftype *cft, u64 val) |
5791 | { |
5792 | struct mem_cgroup *memcg = mem_cgroup_from_css(css); |
5793 | struct mem_cgroup *parent = mem_cgroup_from_css(css_parent(&memcg->css)); |
5794 | |
5795 | /* cannot set to root cgroup and only 0 and 1 are allowed */ |
5796 | if (!parent || !((val == 0) || (val == 1))) |
5797 | return -EINVAL; |
5798 | |
5799 | mutex_lock(&memcg_create_mutex); |
5800 | /* oom-kill-disable is a flag for subhierarchy. */ |
5801 | if ((parent->use_hierarchy) || memcg_has_children(memcg)) { |
5802 | mutex_unlock(&memcg_create_mutex); |
5803 | return -EINVAL; |
5804 | } |
5805 | memcg->oom_kill_disable = val; |
5806 | if (!val) |
5807 | memcg_oom_recover(memcg); |
5808 | mutex_unlock(&memcg_create_mutex); |
5809 | return 0; |
5810 | } |
5811 | |
5812 | #ifdef CONFIG_MEMCG_KMEM |
5813 | static int memcg_init_kmem(struct mem_cgroup *memcg, struct cgroup_subsys *ss) |
5814 | { |
5815 | int ret; |
5816 | |
5817 | memcg->kmemcg_id = -1; |
5818 | ret = memcg_propagate_kmem(memcg); |
5819 | if (ret) |
5820 | return ret; |
5821 | |
5822 | return mem_cgroup_sockets_init(memcg, ss); |
5823 | } |
5824 | |
5825 | static void memcg_destroy_kmem(struct mem_cgroup *memcg) |
5826 | { |
5827 | mem_cgroup_sockets_destroy(memcg); |
5828 | } |
5829 | |
5830 | static void kmem_cgroup_css_offline(struct mem_cgroup *memcg) |
5831 | { |
5832 | if (!memcg_kmem_is_active(memcg)) |
5833 | return; |
5834 | |
5835 | /* |
5836 | * kmem charges can outlive the cgroup. In the case of slab |
5837 | * pages, for instance, a page contain objects from various |
5838 | * processes. As we prevent from taking a reference for every |
5839 | * such allocation we have to be careful when doing uncharge |
5840 | * (see memcg_uncharge_kmem) and here during offlining. |
5841 | * |
5842 | * The idea is that that only the _last_ uncharge which sees |
5843 | * the dead memcg will drop the last reference. An additional |
5844 | * reference is taken here before the group is marked dead |
5845 | * which is then paired with css_put during uncharge resp. here. |
5846 | * |
5847 | * Although this might sound strange as this path is called from |
5848 | * css_offline() when the referencemight have dropped down to 0 |
5849 | * and shouldn't be incremented anymore (css_tryget would fail) |
5850 | * we do not have other options because of the kmem allocations |
5851 | * lifetime. |
5852 | */ |
5853 | css_get(&memcg->css); |
5854 | |
5855 | memcg_kmem_mark_dead(memcg); |
5856 | |
5857 | if (res_counter_read_u64(&memcg->kmem, RES_USAGE) != 0) |
5858 | return; |
5859 | |
5860 | if (memcg_kmem_test_and_clear_dead(memcg)) |
5861 | css_put(&memcg->css); |
5862 | } |
5863 | #else |
5864 | static int memcg_init_kmem(struct mem_cgroup *memcg, struct cgroup_subsys *ss) |
5865 | { |
5866 | return 0; |
5867 | } |
5868 | |
5869 | static void memcg_destroy_kmem(struct mem_cgroup *memcg) |
5870 | { |
5871 | } |
5872 | |
5873 | static void kmem_cgroup_css_offline(struct mem_cgroup *memcg) |
5874 | { |
5875 | } |
5876 | #endif |
5877 | |
5878 | /* |
5879 | * DO NOT USE IN NEW FILES. |
5880 | * |
5881 | * "cgroup.event_control" implementation. |
5882 | * |
5883 | * This is way over-engineered. It tries to support fully configurable |
5884 | * events for each user. Such level of flexibility is completely |
5885 | * unnecessary especially in the light of the planned unified hierarchy. |
5886 | * |
5887 | * Please deprecate this and replace with something simpler if at all |
5888 | * possible. |
5889 | */ |
5890 | |
5891 | /* |
5892 | * Unregister event and free resources. |
5893 | * |
5894 | * Gets called from workqueue. |
5895 | */ |
5896 | static void memcg_event_remove(struct work_struct *work) |
5897 | { |
5898 | struct mem_cgroup_event *event = |
5899 | container_of(work, struct mem_cgroup_event, remove); |
5900 | struct mem_cgroup *memcg = event->memcg; |
5901 | |
5902 | remove_wait_queue(event->wqh, &event->wait); |
5903 | |
5904 | event->unregister_event(memcg, event->eventfd); |
5905 | |
5906 | /* Notify userspace the event is going away. */ |
5907 | eventfd_signal(event->eventfd, 1); |
5908 | |
5909 | eventfd_ctx_put(event->eventfd); |
5910 | kfree(event); |
5911 | css_put(&memcg->css); |
5912 | } |
5913 | |
5914 | /* |
5915 | * Gets called on POLLHUP on eventfd when user closes it. |
5916 | * |
5917 | * Called with wqh->lock held and interrupts disabled. |
5918 | */ |
5919 | static int memcg_event_wake(wait_queue_t *wait, unsigned mode, |
5920 | int sync, void *key) |
5921 | { |
5922 | struct mem_cgroup_event *event = |
5923 | container_of(wait, struct mem_cgroup_event, wait); |
5924 | struct mem_cgroup *memcg = event->memcg; |
5925 | unsigned long flags = (unsigned long)key; |
5926 | |
5927 | if (flags & POLLHUP) { |
5928 | /* |
5929 | * If the event has been detached at cgroup removal, we |
5930 | * can simply return knowing the other side will cleanup |
5931 | * for us. |
5932 | * |
5933 | * We can't race against event freeing since the other |
5934 | * side will require wqh->lock via remove_wait_queue(), |
5935 | * which we hold. |
5936 | */ |
5937 | spin_lock(&memcg->event_list_lock); |
5938 | if (!list_empty(&event->list)) { |
5939 | list_del_init(&event->list); |
5940 | /* |
5941 | * We are in atomic context, but cgroup_event_remove() |
5942 | * may sleep, so we have to call it in workqueue. |
5943 | */ |
5944 | schedule_work(&event->remove); |
5945 | } |
5946 | spin_unlock(&memcg->event_list_lock); |
5947 | } |
5948 | |
5949 | return 0; |
5950 | } |
5951 | |
5952 | static void memcg_event_ptable_queue_proc(struct file *file, |
5953 | wait_queue_head_t *wqh, poll_table *pt) |
5954 | { |
5955 | struct mem_cgroup_event *event = |
5956 | container_of(pt, struct mem_cgroup_event, pt); |
5957 | |
5958 | event->wqh = wqh; |
5959 | add_wait_queue(wqh, &event->wait); |
5960 | } |
5961 | |
5962 | /* |
5963 | * DO NOT USE IN NEW FILES. |
5964 | * |
5965 | * Parse input and register new cgroup event handler. |
5966 | * |
5967 | * Input must be in format '<event_fd> <control_fd> <args>'. |
5968 | * Interpretation of args is defined by control file implementation. |
5969 | */ |
5970 | static int memcg_write_event_control(struct cgroup_subsys_state *css, |
5971 | struct cftype *cft, char *buffer) |
5972 | { |
5973 | struct mem_cgroup *memcg = mem_cgroup_from_css(css); |
5974 | struct mem_cgroup_event *event; |
5975 | struct cgroup_subsys_state *cfile_css; |
5976 | unsigned int efd, cfd; |
5977 | struct fd efile; |
5978 | struct fd cfile; |
5979 | const char *name; |
5980 | char *endp; |
5981 | int ret; |
5982 | |
5983 | efd = simple_strtoul(buffer, &endp, 10); |
5984 | if (*endp != ' ') |
5985 | return -EINVAL; |
5986 | buffer = endp + 1; |
5987 | |
5988 | cfd = simple_strtoul(buffer, &endp, 10); |
5989 | if ((*endp != ' ') && (*endp != '\0')) |
5990 | return -EINVAL; |
5991 | buffer = endp + 1; |
5992 | |
5993 | event = kzalloc(sizeof(*event), GFP_KERNEL); |
5994 | if (!event) |
5995 | return -ENOMEM; |
5996 | |
5997 | event->memcg = memcg; |
5998 | INIT_LIST_HEAD(&event->list); |
5999 | init_poll_funcptr(&event->pt, memcg_event_ptable_queue_proc); |
6000 | init_waitqueue_func_entry(&event->wait, memcg_event_wake); |
6001 | INIT_WORK(&event->remove, memcg_event_remove); |
6002 | |
6003 | efile = fdget(efd); |
6004 | if (!efile.file) { |
6005 | ret = -EBADF; |
6006 | goto out_kfree; |
6007 | } |
6008 | |
6009 | event->eventfd = eventfd_ctx_fileget(efile.file); |
6010 | if (IS_ERR(event->eventfd)) { |
6011 | ret = PTR_ERR(event->eventfd); |
6012 | goto out_put_efile; |
6013 | } |
6014 | |
6015 | cfile = fdget(cfd); |
6016 | if (!cfile.file) { |
6017 | ret = -EBADF; |
6018 | goto out_put_eventfd; |
6019 | } |
6020 | |
6021 | /* the process need read permission on control file */ |
6022 | /* AV: shouldn't we check that it's been opened for read instead? */ |
6023 | ret = inode_permission(file_inode(cfile.file), MAY_READ); |
6024 | if (ret < 0) |
6025 | goto out_put_cfile; |
6026 | |
6027 | /* |
6028 | * Determine the event callbacks and set them in @event. This used |
6029 | * to be done via struct cftype but cgroup core no longer knows |
6030 | * about these events. The following is crude but the whole thing |
6031 | * is for compatibility anyway. |
6032 | * |
6033 | * DO NOT ADD NEW FILES. |
6034 | */ |
6035 | name = cfile.file->f_dentry->d_name.name; |
6036 | |
6037 | if (!strcmp(name, "memory.usage_in_bytes")) { |
6038 | event->register_event = mem_cgroup_usage_register_event; |
6039 | event->unregister_event = mem_cgroup_usage_unregister_event; |
6040 | } else if (!strcmp(name, "memory.oom_control")) { |
6041 | event->register_event = mem_cgroup_oom_register_event; |
6042 | event->unregister_event = mem_cgroup_oom_unregister_event; |
6043 | } else if (!strcmp(name, "memory.pressure_level")) { |
6044 | event->register_event = vmpressure_register_event; |
6045 | event->unregister_event = vmpressure_unregister_event; |
6046 | } else if (!strcmp(name, "memory.memsw.usage_in_bytes")) { |
6047 | event->register_event = memsw_cgroup_usage_register_event; |
6048 | event->unregister_event = memsw_cgroup_usage_unregister_event; |
6049 | } else { |
6050 | ret = -EINVAL; |
6051 | goto out_put_cfile; |
6052 | } |
6053 | |
6054 | /* |
6055 | * Verify @cfile should belong to @css. Also, remaining events are |
6056 | * automatically removed on cgroup destruction but the removal is |
6057 | * asynchronous, so take an extra ref on @css. |
6058 | */ |
6059 | cfile_css = css_tryget_from_dir(cfile.file->f_dentry->d_parent, |
6060 | &memory_cgrp_subsys); |
6061 | ret = -EINVAL; |
6062 | if (IS_ERR(cfile_css)) |
6063 | goto out_put_cfile; |
6064 | if (cfile_css != css) { |
6065 | css_put(cfile_css); |
6066 | goto out_put_cfile; |
6067 | } |
6068 | |
6069 | ret = event->register_event(memcg, event->eventfd, buffer); |
6070 | if (ret) |
6071 | goto out_put_css; |
6072 | |
6073 | efile.file->f_op->poll(efile.file, &event->pt); |
6074 | |
6075 | spin_lock(&memcg->event_list_lock); |
6076 | list_add(&event->list, &memcg->event_list); |
6077 | spin_unlock(&memcg->event_list_lock); |
6078 | |
6079 | fdput(cfile); |
6080 | fdput(efile); |
6081 | |
6082 | return 0; |
6083 | |
6084 | out_put_css: |
6085 | css_put(css); |
6086 | out_put_cfile: |
6087 | fdput(cfile); |
6088 | out_put_eventfd: |
6089 | eventfd_ctx_put(event->eventfd); |
6090 | out_put_efile: |
6091 | fdput(efile); |
6092 | out_kfree: |
6093 | kfree(event); |
6094 | |
6095 | return ret; |
6096 | } |
6097 | |
6098 | static struct cftype mem_cgroup_files[] = { |
6099 | { |
6100 | .name = "usage_in_bytes", |
6101 | .private = MEMFILE_PRIVATE(_MEM, RES_USAGE), |
6102 | .read_u64 = mem_cgroup_read_u64, |
6103 | }, |
6104 | { |
6105 | .name = "max_usage_in_bytes", |
6106 | .private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE), |
6107 | .trigger = mem_cgroup_reset, |
6108 | .read_u64 = mem_cgroup_read_u64, |
6109 | }, |
6110 | { |
6111 | .name = "limit_in_bytes", |
6112 | .private = MEMFILE_PRIVATE(_MEM, RES_LIMIT), |
6113 | .write_string = mem_cgroup_write, |
6114 | .read_u64 = mem_cgroup_read_u64, |
6115 | }, |
6116 | { |
6117 | .name = "soft_limit_in_bytes", |
6118 | .private = MEMFILE_PRIVATE(_MEM, RES_SOFT_LIMIT), |
6119 | .write_string = mem_cgroup_write, |
6120 | .read_u64 = mem_cgroup_read_u64, |
6121 | }, |
6122 | { |
6123 | .name = "failcnt", |
6124 | .private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT), |
6125 | .trigger = mem_cgroup_reset, |
6126 | .read_u64 = mem_cgroup_read_u64, |
6127 | }, |
6128 | { |
6129 | .name = "stat", |
6130 | .seq_show = memcg_stat_show, |
6131 | }, |
6132 | { |
6133 | .name = "force_empty", |
6134 | .trigger = mem_cgroup_force_empty_write, |
6135 | }, |
6136 | { |
6137 | .name = "use_hierarchy", |
6138 | .flags = CFTYPE_INSANE, |
6139 | .write_u64 = mem_cgroup_hierarchy_write, |
6140 | .read_u64 = mem_cgroup_hierarchy_read, |
6141 | }, |
6142 | { |
6143 | .name = "cgroup.event_control", /* XXX: for compat */ |
6144 | .write_string = memcg_write_event_control, |
6145 | .flags = CFTYPE_NO_PREFIX, |
6146 | .mode = S_IWUGO, |
6147 | }, |
6148 | { |
6149 | .name = "swappiness", |
6150 | .read_u64 = mem_cgroup_swappiness_read, |
6151 | .write_u64 = mem_cgroup_swappiness_write, |
6152 | }, |
6153 | { |
6154 | .name = "move_charge_at_immigrate", |
6155 | .read_u64 = mem_cgroup_move_charge_read, |
6156 | .write_u64 = mem_cgroup_move_charge_write, |
6157 | }, |
6158 | { |
6159 | .name = "oom_control", |
6160 | .seq_show = mem_cgroup_oom_control_read, |
6161 | .write_u64 = mem_cgroup_oom_control_write, |
6162 | .private = MEMFILE_PRIVATE(_OOM_TYPE, OOM_CONTROL), |
6163 | }, |
6164 | { |
6165 | .name = "pressure_level", |
6166 | }, |
6167 | #ifdef CONFIG_NUMA |
6168 | { |
6169 | .name = "numa_stat", |
6170 | .seq_show = memcg_numa_stat_show, |
6171 | }, |
6172 | #endif |
6173 | #ifdef CONFIG_MEMCG_KMEM |
6174 | { |
6175 | .name = "kmem.limit_in_bytes", |
6176 | .private = MEMFILE_PRIVATE(_KMEM, RES_LIMIT), |
6177 | .write_string = mem_cgroup_write, |
6178 | .read_u64 = mem_cgroup_read_u64, |
6179 | }, |
6180 | { |
6181 | .name = "kmem.usage_in_bytes", |
6182 | .private = MEMFILE_PRIVATE(_KMEM, RES_USAGE), |
6183 | .read_u64 = mem_cgroup_read_u64, |
6184 | }, |
6185 | { |
6186 | .name = "kmem.failcnt", |
6187 | .private = MEMFILE_PRIVATE(_KMEM, RES_FAILCNT), |
6188 | .trigger = mem_cgroup_reset, |
6189 | .read_u64 = mem_cgroup_read_u64, |
6190 | }, |
6191 | { |
6192 | .name = "kmem.max_usage_in_bytes", |
6193 | .private = MEMFILE_PRIVATE(_KMEM, RES_MAX_USAGE), |
6194 | .trigger = mem_cgroup_reset, |
6195 | .read_u64 = mem_cgroup_read_u64, |
6196 | }, |
6197 | #ifdef CONFIG_SLABINFO |
6198 | { |
6199 | .name = "kmem.slabinfo", |
6200 | .seq_show = mem_cgroup_slabinfo_read, |
6201 | }, |
6202 | #endif |
6203 | #endif |
6204 | { }, /* terminate */ |
6205 | }; |
6206 | |
6207 | #ifdef CONFIG_MEMCG_SWAP |
6208 | static struct cftype memsw_cgroup_files[] = { |
6209 | { |
6210 | .name = "memsw.usage_in_bytes", |
6211 | .private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE), |
6212 | .read_u64 = mem_cgroup_read_u64, |
6213 | }, |
6214 | { |
6215 | .name = "memsw.max_usage_in_bytes", |
6216 | .private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE), |
6217 | .trigger = mem_cgroup_reset, |
6218 | .read_u64 = mem_cgroup_read_u64, |
6219 | }, |
6220 | { |
6221 | .name = "memsw.limit_in_bytes", |
6222 | .private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT), |
6223 | .write_string = mem_cgroup_write, |
6224 | .read_u64 = mem_cgroup_read_u64, |
6225 | }, |
6226 | { |
6227 | .name = "memsw.failcnt", |
6228 | .private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT), |
6229 | .trigger = mem_cgroup_reset, |
6230 | .read_u64 = mem_cgroup_read_u64, |
6231 | }, |
6232 | { }, /* terminate */ |
6233 | }; |
6234 | #endif |
6235 | static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *memcg, int node) |
6236 | { |
6237 | struct mem_cgroup_per_node *pn; |
6238 | struct mem_cgroup_per_zone *mz; |
6239 | int zone, tmp = node; |
6240 | /* |
6241 | * This routine is called against possible nodes. |
6242 | * But it's BUG to call kmalloc() against offline node. |
6243 | * |
6244 | * TODO: this routine can waste much memory for nodes which will |
6245 | * never be onlined. It's better to use memory hotplug callback |
6246 | * function. |
6247 | */ |
6248 | if (!node_state(node, N_NORMAL_MEMORY)) |
6249 | tmp = -1; |
6250 | pn = kzalloc_node(sizeof(*pn), GFP_KERNEL, tmp); |
6251 | if (!pn) |
6252 | return 1; |
6253 | |
6254 | for (zone = 0; zone < MAX_NR_ZONES; zone++) { |
6255 | mz = &pn->zoneinfo[zone]; |
6256 | lruvec_init(&mz->lruvec); |
6257 | mz->usage_in_excess = 0; |
6258 | mz->on_tree = false; |
6259 | mz->memcg = memcg; |
6260 | } |
6261 | memcg->nodeinfo[node] = pn; |
6262 | return 0; |
6263 | } |
6264 | |
6265 | static void free_mem_cgroup_per_zone_info(struct mem_cgroup *memcg, int node) |
6266 | { |
6267 | kfree(memcg->nodeinfo[node]); |
6268 | } |
6269 | |
6270 | static struct mem_cgroup *mem_cgroup_alloc(void) |
6271 | { |
6272 | struct mem_cgroup *memcg; |
6273 | size_t size; |
6274 | |
6275 | size = sizeof(struct mem_cgroup); |
6276 | size += nr_node_ids * sizeof(struct mem_cgroup_per_node *); |
6277 | |
6278 | memcg = kzalloc(size, GFP_KERNEL); |
6279 | if (!memcg) |
6280 | return NULL; |
6281 | |
6282 | memcg->stat = alloc_percpu(struct mem_cgroup_stat_cpu); |
6283 | if (!memcg->stat) |
6284 | goto out_free; |
6285 | spin_lock_init(&memcg->pcp_counter_lock); |
6286 | return memcg; |
6287 | |
6288 | out_free: |
6289 | kfree(memcg); |
6290 | return NULL; |
6291 | } |
6292 | |
6293 | /* |
6294 | * At destroying mem_cgroup, references from swap_cgroup can remain. |
6295 | * (scanning all at force_empty is too costly...) |
6296 | * |
6297 | * Instead of clearing all references at force_empty, we remember |
6298 | * the number of reference from swap_cgroup and free mem_cgroup when |
6299 | * it goes down to 0. |
6300 | * |
6301 | * Removal of cgroup itself succeeds regardless of refs from swap. |
6302 | */ |
6303 | |
6304 | static void __mem_cgroup_free(struct mem_cgroup *memcg) |
6305 | { |
6306 | int node; |
6307 | |
6308 | mem_cgroup_remove_from_trees(memcg); |
6309 | |
6310 | for_each_node(node) |
6311 | free_mem_cgroup_per_zone_info(memcg, node); |
6312 | |
6313 | free_percpu(memcg->stat); |
6314 | |
6315 | /* |
6316 | * We need to make sure that (at least for now), the jump label |
6317 | * destruction code runs outside of the cgroup lock. This is because |
6318 | * get_online_cpus(), which is called from the static_branch update, |
6319 | * can't be called inside the cgroup_lock. cpusets are the ones |
6320 | * enforcing this dependency, so if they ever change, we might as well. |
6321 | * |
6322 | * schedule_work() will guarantee this happens. Be careful if you need |
6323 | * to move this code around, and make sure it is outside |
6324 | * the cgroup_lock. |
6325 | */ |
6326 | disarm_static_keys(memcg); |
6327 | kfree(memcg); |
6328 | } |
6329 | |
6330 | /* |
6331 | * Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled. |
6332 | */ |
6333 | struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *memcg) |
6334 | { |
6335 | if (!memcg->res.parent) |
6336 | return NULL; |
6337 | return mem_cgroup_from_res_counter(memcg->res.parent, res); |
6338 | } |
6339 | EXPORT_SYMBOL(parent_mem_cgroup); |
6340 | |
6341 | static void __init mem_cgroup_soft_limit_tree_init(void) |
6342 | { |
6343 | struct mem_cgroup_tree_per_node *rtpn; |
6344 | struct mem_cgroup_tree_per_zone *rtpz; |
6345 | int tmp, node, zone; |
6346 | |
6347 | for_each_node(node) { |
6348 | tmp = node; |
6349 | if (!node_state(node, N_NORMAL_MEMORY)) |
6350 | tmp = -1; |
6351 | rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL, tmp); |
6352 | BUG_ON(!rtpn); |
6353 | |
6354 | soft_limit_tree.rb_tree_per_node[node] = rtpn; |
6355 | |
6356 | for (zone = 0; zone < MAX_NR_ZONES; zone++) { |
6357 | rtpz = &rtpn->rb_tree_per_zone[zone]; |
6358 | rtpz->rb_root = RB_ROOT; |
6359 | spin_lock_init(&rtpz->lock); |
6360 | } |
6361 | } |
6362 | } |
6363 | |
6364 | static struct cgroup_subsys_state * __ref |
6365 | mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) |
6366 | { |
6367 | struct mem_cgroup *memcg; |
6368 | long error = -ENOMEM; |
6369 | int node; |
6370 | |
6371 | memcg = mem_cgroup_alloc(); |
6372 | if (!memcg) |
6373 | return ERR_PTR(error); |
6374 | |
6375 | for_each_node(node) |
6376 | if (alloc_mem_cgroup_per_zone_info(memcg, node)) |
6377 | goto free_out; |
6378 | |
6379 | /* root ? */ |
6380 | if (parent_css == NULL) { |
6381 | root_mem_cgroup = memcg; |
6382 | res_counter_init(&memcg->res, NULL); |
6383 | res_counter_init(&memcg->memsw, NULL); |
6384 | res_counter_init(&memcg->kmem, NULL); |
6385 | } |
6386 | |
6387 | memcg->last_scanned_node = MAX_NUMNODES; |
6388 | INIT_LIST_HEAD(&memcg->oom_notify); |
6389 | memcg->move_charge_at_immigrate = 0; |
6390 | mutex_init(&memcg->thresholds_lock); |
6391 | spin_lock_init(&memcg->move_lock); |
6392 | vmpressure_init(&memcg->vmpressure); |
6393 | INIT_LIST_HEAD(&memcg->event_list); |
6394 | spin_lock_init(&memcg->event_list_lock); |
6395 | |
6396 | return &memcg->css; |
6397 | |
6398 | free_out: |
6399 | __mem_cgroup_free(memcg); |
6400 | return ERR_PTR(error); |
6401 | } |
6402 | |
6403 | static int |
6404 | mem_cgroup_css_online(struct cgroup_subsys_state *css) |
6405 | { |
6406 | struct mem_cgroup *memcg = mem_cgroup_from_css(css); |
6407 | struct mem_cgroup *parent = mem_cgroup_from_css(css_parent(css)); |
6408 | |
6409 | if (css->cgroup->id > MEM_CGROUP_ID_MAX) |
6410 | return -ENOSPC; |
6411 | |
6412 | if (!parent) |
6413 | return 0; |
6414 | |
6415 | mutex_lock(&memcg_create_mutex); |
6416 | |
6417 | memcg->use_hierarchy = parent->use_hierarchy; |
6418 | memcg->oom_kill_disable = parent->oom_kill_disable; |
6419 | memcg->swappiness = mem_cgroup_swappiness(parent); |
6420 | |
6421 | if (parent->use_hierarchy) { |
6422 | res_counter_init(&memcg->res, &parent->res); |
6423 | res_counter_init(&memcg->memsw, &parent->memsw); |
6424 | res_counter_init(&memcg->kmem, &parent->kmem); |
6425 | |
6426 | /* |
6427 | * No need to take a reference to the parent because cgroup |
6428 | * core guarantees its existence. |
6429 | */ |
6430 | } else { |
6431 | res_counter_init(&memcg->res, NULL); |
6432 | res_counter_init(&memcg->memsw, NULL); |
6433 | res_counter_init(&memcg->kmem, NULL); |
6434 | /* |
6435 | * Deeper hierachy with use_hierarchy == false doesn't make |
6436 | * much sense so let cgroup subsystem know about this |
6437 | * unfortunate state in our controller. |
6438 | */ |
6439 | if (parent != root_mem_cgroup) |
6440 | memory_cgrp_subsys.broken_hierarchy = true; |
6441 | } |
6442 | mutex_unlock(&memcg_create_mutex); |
6443 | |
6444 | return memcg_init_kmem(memcg, &memory_cgrp_subsys); |
6445 | } |
6446 | |
6447 | /* |
6448 | * Announce all parents that a group from their hierarchy is gone. |
6449 | */ |
6450 | static void mem_cgroup_invalidate_reclaim_iterators(struct mem_cgroup *memcg) |
6451 | { |
6452 | struct mem_cgroup *parent = memcg; |
6453 | |
6454 | while ((parent = parent_mem_cgroup(parent))) |
6455 | mem_cgroup_iter_invalidate(parent); |
6456 | |
6457 | /* |
6458 | * if the root memcg is not hierarchical we have to check it |
6459 | * explicitely. |
6460 | */ |
6461 | if (!root_mem_cgroup->use_hierarchy) |
6462 | mem_cgroup_iter_invalidate(root_mem_cgroup); |
6463 | } |
6464 | |
6465 | static void mem_cgroup_css_offline(struct cgroup_subsys_state *css) |
6466 | { |
6467 | struct mem_cgroup *memcg = mem_cgroup_from_css(css); |
6468 | struct mem_cgroup_event *event, *tmp; |
6469 | struct cgroup_subsys_state *iter; |
6470 | |
6471 | /* |
6472 | * Unregister events and notify userspace. |
6473 | * Notify userspace about cgroup removing only after rmdir of cgroup |
6474 | * directory to avoid race between userspace and kernelspace. |
6475 | */ |
6476 | spin_lock(&memcg->event_list_lock); |
6477 | list_for_each_entry_safe(event, tmp, &memcg->event_list, list) { |
6478 | list_del_init(&event->list); |
6479 | schedule_work(&event->remove); |
6480 | } |
6481 | spin_unlock(&memcg->event_list_lock); |
6482 | |
6483 | kmem_cgroup_css_offline(memcg); |
6484 | |
6485 | mem_cgroup_invalidate_reclaim_iterators(memcg); |
6486 | |
6487 | /* |
6488 | * This requires that offlining is serialized. Right now that is |
6489 | * guaranteed because css_killed_work_fn() holds the cgroup_mutex. |
6490 | */ |
6491 | css_for_each_descendant_post(iter, css) |
6492 | mem_cgroup_reparent_charges(mem_cgroup_from_css(iter)); |
6493 | |
6494 | mem_cgroup_destroy_all_caches(memcg); |
6495 | vmpressure_cleanup(&memcg->vmpressure); |
6496 | } |
6497 | |
6498 | static void mem_cgroup_css_free(struct cgroup_subsys_state *css) |
6499 | { |
6500 | struct mem_cgroup *memcg = mem_cgroup_from_css(css); |
6501 | /* |
6502 | * XXX: css_offline() would be where we should reparent all |
6503 | * memory to prepare the cgroup for destruction. However, |
6504 | * memcg does not do css_tryget() and res_counter charging |
6505 | * under the same RCU lock region, which means that charging |
6506 | * could race with offlining. Offlining only happens to |
6507 | * cgroups with no tasks in them but charges can show up |
6508 | * without any tasks from the swapin path when the target |
6509 | * memcg is looked up from the swapout record and not from the |
6510 | * current task as it usually is. A race like this can leak |
6511 | * charges and put pages with stale cgroup pointers into |
6512 | * circulation: |
6513 | * |
6514 | * #0 #1 |
6515 | * lookup_swap_cgroup_id() |
6516 | * rcu_read_lock() |
6517 | * mem_cgroup_lookup() |
6518 | * css_tryget() |
6519 | * rcu_read_unlock() |
6520 | * disable css_tryget() |
6521 | * call_rcu() |
6522 | * offline_css() |
6523 | * reparent_charges() |
6524 | * res_counter_charge() |
6525 | * css_put() |
6526 | * css_free() |
6527 | * pc->mem_cgroup = dead memcg |
6528 | * add page to lru |
6529 | * |
6530 | * The bulk of the charges are still moved in offline_css() to |
6531 | * avoid pinning a lot of pages in case a long-term reference |
6532 | * like a swapout record is deferring the css_free() to long |
6533 | * after offlining. But this makes sure we catch any charges |
6534 | * made after offlining: |
6535 | */ |
6536 | mem_cgroup_reparent_charges(memcg); |
6537 | |
6538 | memcg_destroy_kmem(memcg); |
6539 | __mem_cgroup_free(memcg); |
6540 | } |
6541 | |
6542 | #ifdef CONFIG_MMU |
6543 | /* Handlers for move charge at task migration. */ |
6544 | #define PRECHARGE_COUNT_AT_ONCE 256 |
6545 | static int mem_cgroup_do_precharge(unsigned long count) |
6546 | { |
6547 | int ret = 0; |
6548 | int batch_count = PRECHARGE_COUNT_AT_ONCE; |
6549 | struct mem_cgroup *memcg = mc.to; |
6550 | |
6551 | if (mem_cgroup_is_root(memcg)) { |
6552 | mc.precharge += count; |
6553 | /* we don't need css_get for root */ |
6554 | return ret; |
6555 | } |
6556 | /* try to charge at once */ |
6557 | if (count > 1) { |
6558 | struct res_counter *dummy; |
6559 | /* |
6560 | * "memcg" cannot be under rmdir() because we've already checked |
6561 | * by cgroup_lock_live_cgroup() that it is not removed and we |
6562 | * are still under the same cgroup_mutex. So we can postpone |
6563 | * css_get(). |
6564 | */ |
6565 | if (res_counter_charge(&memcg->res, PAGE_SIZE * count, &dummy)) |
6566 | goto one_by_one; |
6567 | if (do_swap_account && res_counter_charge(&memcg->memsw, |
6568 | PAGE_SIZE * count, &dummy)) { |
6569 | res_counter_uncharge(&memcg->res, PAGE_SIZE * count); |
6570 | goto one_by_one; |
6571 | } |
6572 | mc.precharge += count; |
6573 | return ret; |
6574 | } |
6575 | one_by_one: |
6576 | /* fall back to one by one charge */ |
6577 | while (count--) { |
6578 | if (signal_pending(current)) { |
6579 | ret = -EINTR; |
6580 | break; |
6581 | } |
6582 | if (!batch_count--) { |
6583 | batch_count = PRECHARGE_COUNT_AT_ONCE; |
6584 | cond_resched(); |
6585 | } |
6586 | ret = mem_cgroup_try_charge(memcg, GFP_KERNEL, 1, false); |
6587 | if (ret) |
6588 | /* mem_cgroup_clear_mc() will do uncharge later */ |
6589 | return ret; |
6590 | mc.precharge++; |
6591 | } |
6592 | return ret; |
6593 | } |
6594 | |
6595 | /** |
6596 | * get_mctgt_type - get target type of moving charge |
6597 | * @vma: the vma the pte to be checked belongs |
6598 | * @addr: the address corresponding to the pte to be checked |
6599 | * @ptent: the pte to be checked |
6600 | * @target: the pointer the target page or swap ent will be stored(can be NULL) |
6601 | * |
6602 | * Returns |
6603 | * 0(MC_TARGET_NONE): if the pte is not a target for move charge. |
6604 | * 1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for |
6605 | * move charge. if @target is not NULL, the page is stored in target->page |
6606 | * with extra refcnt got(Callers should handle it). |
6607 | * 2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a |
6608 | * target for charge migration. if @target is not NULL, the entry is stored |
6609 | * in target->ent. |
6610 | * |
6611 | * Called with pte lock held. |
6612 | */ |
6613 | union mc_target { |
6614 | struct page *page; |
6615 | swp_entry_t ent; |
6616 | }; |
6617 | |
6618 | enum mc_target_type { |
6619 | MC_TARGET_NONE = 0, |
6620 | MC_TARGET_PAGE, |
6621 | MC_TARGET_SWAP, |
6622 | }; |
6623 | |
6624 | static struct page *mc_handle_present_pte(struct vm_area_struct *vma, |
6625 | unsigned long addr, pte_t ptent) |
6626 | { |
6627 | struct page *page = vm_normal_page(vma, addr, ptent); |
6628 | |
6629 | if (!page || !page_mapped(page)) |
6630 | return NULL; |
6631 | if (PageAnon(page)) { |
6632 | /* we don't move shared anon */ |
6633 | if (!move_anon()) |
6634 | return NULL; |
6635 | } else if (!move_file()) |
6636 | /* we ignore mapcount for file pages */ |
6637 | return NULL; |
6638 | if (!get_page_unless_zero(page)) |
6639 | return NULL; |
6640 | |
6641 | return page; |
6642 | } |
6643 | |
6644 | #ifdef CONFIG_SWAP |
6645 | static struct page *mc_handle_swap_pte(struct vm_area_struct *vma, |
6646 | unsigned long addr, pte_t ptent, swp_entry_t *entry) |
6647 | { |
6648 | struct page *page = NULL; |
6649 | swp_entry_t ent = pte_to_swp_entry(ptent); |
6650 | |
6651 | if (!move_anon() || non_swap_entry(ent)) |
6652 | return NULL; |
6653 | /* |
6654 | * Because lookup_swap_cache() updates some statistics counter, |
6655 | * we call find_get_page() with swapper_space directly. |
6656 | */ |
6657 | page = find_get_page(swap_address_space(ent), ent.val); |
6658 | if (do_swap_account) |
6659 | entry->val = ent.val; |
6660 | |
6661 | return page; |
6662 | } |
6663 | #else |
6664 | static struct page *mc_handle_swap_pte(struct vm_area_struct *vma, |
6665 | unsigned long addr, pte_t ptent, swp_entry_t *entry) |
6666 | { |
6667 | return NULL; |
6668 | } |
6669 | #endif |
6670 | |
6671 | static struct page *mc_handle_file_pte(struct vm_area_struct *vma, |
6672 | unsigned long addr, pte_t ptent, swp_entry_t *entry) |
6673 | { |
6674 | struct page *page = NULL; |
6675 | struct address_space *mapping; |
6676 | pgoff_t pgoff; |
6677 | |
6678 | if (!vma->vm_file) /* anonymous vma */ |
6679 | return NULL; |
6680 | if (!move_file()) |
6681 | return NULL; |
6682 | |
6683 | mapping = vma->vm_file->f_mapping; |
6684 | if (pte_none(ptent)) |
6685 | pgoff = linear_page_index(vma, addr); |
6686 | else /* pte_file(ptent) is true */ |
6687 | pgoff = pte_to_pgoff(ptent); |
6688 | |
6689 | /* page is moved even if it's not RSS of this task(page-faulted). */ |
6690 | #ifdef CONFIG_SWAP |
6691 | /* shmem/tmpfs may report page out on swap: account for that too. */ |
6692 | if (shmem_mapping(mapping)) { |
6693 | page = find_get_entry(mapping, pgoff); |
6694 | if (radix_tree_exceptional_entry(page)) { |
6695 | swp_entry_t swp = radix_to_swp_entry(page); |
6696 | if (do_swap_account) |
6697 | *entry = swp; |
6698 | page = find_get_page(swap_address_space(swp), swp.val); |
6699 | } |
6700 | } else |
6701 | page = find_get_page(mapping, pgoff); |
6702 | #else |
6703 | page = find_get_page(mapping, pgoff); |
6704 | #endif |
6705 | return page; |
6706 | } |
6707 | |
6708 | static enum mc_target_type get_mctgt_type(struct vm_area_struct *vma, |
6709 | unsigned long addr, pte_t ptent, union mc_target *target) |
6710 | { |
6711 | struct page *page = NULL; |
6712 | struct page_cgroup *pc; |
6713 | enum mc_target_type ret = MC_TARGET_NONE; |
6714 | swp_entry_t ent = { .val = 0 }; |
6715 | |
6716 | if (pte_present(ptent)) |
6717 | page = mc_handle_present_pte(vma, addr, ptent); |
6718 | else if (is_swap_pte(ptent)) |
6719 | page = mc_handle_swap_pte(vma, addr, ptent, &ent); |
6720 | else if (pte_none(ptent) || pte_file(ptent)) |
6721 | page = mc_handle_file_pte(vma, addr, ptent, &ent); |
6722 | |
6723 | if (!page && !ent.val) |
6724 | return ret; |
6725 | if (page) { |
6726 | pc = lookup_page_cgroup(page); |
6727 | /* |
6728 | * Do only loose check w/o page_cgroup lock. |
6729 | * mem_cgroup_move_account() checks the pc is valid or not under |
6730 | * the lock. |
6731 | */ |
6732 | if (PageCgroupUsed(pc) && pc->mem_cgroup == mc.from) { |
6733 | ret = MC_TARGET_PAGE; |
6734 | if (target) |
6735 | target->page = page; |
6736 | } |
6737 | if (!ret || !target) |
6738 | put_page(page); |
6739 | } |
6740 | /* There is a swap entry and a page doesn't exist or isn't charged */ |
6741 | if (ent.val && !ret && |
6742 | mem_cgroup_id(mc.from) == lookup_swap_cgroup_id(ent)) { |
6743 | ret = MC_TARGET_SWAP; |
6744 | if (target) |
6745 | target->ent = ent; |
6746 | } |
6747 | return ret; |
6748 | } |
6749 | |
6750 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE |
6751 | /* |
6752 | * We don't consider swapping or file mapped pages because THP does not |
6753 | * support them for now. |
6754 | * Caller should make sure that pmd_trans_huge(pmd) is true. |
6755 | */ |
6756 | static enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma, |
6757 | unsigned long addr, pmd_t pmd, union mc_target *target) |
6758 | { |
6759 | struct page *page = NULL; |
6760 | struct page_cgroup *pc; |
6761 | enum mc_target_type ret = MC_TARGET_NONE; |
6762 | |
6763 | page = pmd_page(pmd); |
6764 | VM_BUG_ON_PAGE(!page || !PageHead(page), page); |
6765 | if (!move_anon()) |
6766 | return ret; |
6767 | pc = lookup_page_cgroup(page); |
6768 | if (PageCgroupUsed(pc) && pc->mem_cgroup == mc.from) { |
6769 | ret = MC_TARGET_PAGE; |
6770 | if (target) { |
6771 | get_page(page); |
6772 | target->page = page; |
6773 | } |
6774 | } |
6775 | return ret; |
6776 | } |
6777 | #else |
6778 | static inline enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma, |
6779 | unsigned long addr, pmd_t pmd, union mc_target *target) |
6780 | { |
6781 | return MC_TARGET_NONE; |
6782 | } |
6783 | #endif |
6784 | |
6785 | static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd, |
6786 | unsigned long addr, unsigned long end, |
6787 | struct mm_walk *walk) |
6788 | { |
6789 | struct vm_area_struct *vma = walk->private; |
6790 | pte_t *pte; |
6791 | spinlock_t *ptl; |
6792 | |
6793 | if (pmd_trans_huge_lock(pmd, vma, &ptl) == 1) { |
6794 | if (get_mctgt_type_thp(vma, addr, *pmd, NULL) == MC_TARGET_PAGE) |
6795 | mc.precharge += HPAGE_PMD_NR; |
6796 | spin_unlock(ptl); |
6797 | return 0; |
6798 | } |
6799 | |
6800 | if (pmd_trans_unstable(pmd)) |
6801 | return 0; |
6802 | pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); |
6803 | for (; addr != end; pte++, addr += PAGE_SIZE) |
6804 | if (get_mctgt_type(vma, addr, *pte, NULL)) |
6805 | mc.precharge++; /* increment precharge temporarily */ |
6806 | pte_unmap_unlock(pte - 1, ptl); |
6807 | cond_resched(); |
6808 | |
6809 | return 0; |
6810 | } |
6811 | |
6812 | static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm) |
6813 | { |
6814 | unsigned long precharge; |
6815 | struct vm_area_struct *vma; |
6816 | |
6817 | down_read(&mm->mmap_sem); |
6818 | for (vma = mm->mmap; vma; vma = vma->vm_next) { |
6819 | struct mm_walk mem_cgroup_count_precharge_walk = { |
6820 | .pmd_entry = mem_cgroup_count_precharge_pte_range, |
6821 | .mm = mm, |
6822 | .private = vma, |
6823 | }; |
6824 | if (is_vm_hugetlb_page(vma)) |
6825 | continue; |
6826 | walk_page_range(vma->vm_start, vma->vm_end, |
6827 | &mem_cgroup_count_precharge_walk); |
6828 | } |
6829 | up_read(&mm->mmap_sem); |
6830 | |
6831 | precharge = mc.precharge; |
6832 | mc.precharge = 0; |
6833 | |
6834 | return precharge; |
6835 | } |
6836 | |
6837 | static int mem_cgroup_precharge_mc(struct mm_struct *mm) |
6838 | { |
6839 | unsigned long precharge = mem_cgroup_count_precharge(mm); |
6840 | |
6841 | VM_BUG_ON(mc.moving_task); |
6842 | mc.moving_task = current; |
6843 | return mem_cgroup_do_precharge(precharge); |
6844 | } |
6845 | |
6846 | /* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */ |
6847 | static void __mem_cgroup_clear_mc(void) |
6848 | { |
6849 | struct mem_cgroup *from = mc.from; |
6850 | struct mem_cgroup *to = mc.to; |
6851 | int i; |
6852 | |
6853 | /* we must uncharge all the leftover precharges from mc.to */ |
6854 | if (mc.precharge) { |
6855 | __mem_cgroup_cancel_charge(mc.to, mc.precharge); |
6856 | mc.precharge = 0; |
6857 | } |
6858 | /* |
6859 | * we didn't uncharge from mc.from at mem_cgroup_move_account(), so |
6860 | * we must uncharge here. |
6861 | */ |
6862 | if (mc.moved_charge) { |
6863 | __mem_cgroup_cancel_charge(mc.from, mc.moved_charge); |
6864 | mc.moved_charge = 0; |
6865 | } |
6866 | /* we must fixup refcnts and charges */ |
6867 | if (mc.moved_swap) { |
6868 | /* uncharge swap account from the old cgroup */ |
6869 | if (!mem_cgroup_is_root(mc.from)) |
6870 | res_counter_uncharge(&mc.from->memsw, |
6871 | PAGE_SIZE * mc.moved_swap); |
6872 | |
6873 | for (i = 0; i < mc.moved_swap; i++) |
6874 | css_put(&mc.from->css); |
6875 | |
6876 | if (!mem_cgroup_is_root(mc.to)) { |
6877 | /* |
6878 | * we charged both to->res and to->memsw, so we should |
6879 | * uncharge to->res. |
6880 | */ |
6881 | res_counter_uncharge(&mc.to->res, |
6882 | PAGE_SIZE * mc.moved_swap); |
6883 | } |
6884 | /* we've already done css_get(mc.to) */ |
6885 | mc.moved_swap = 0; |
6886 | } |
6887 | memcg_oom_recover(from); |
6888 | memcg_oom_recover(to); |
6889 | wake_up_all(&mc.waitq); |
6890 | } |
6891 | |
6892 | static void mem_cgroup_clear_mc(void) |
6893 | { |
6894 | struct mem_cgroup *from = mc.from; |
6895 | |
6896 | /* |
6897 | * we must clear moving_task before waking up waiters at the end of |
6898 | * task migration. |
6899 | */ |
6900 | mc.moving_task = NULL; |
6901 | __mem_cgroup_clear_mc(); |
6902 | spin_lock(&mc.lock); |
6903 | mc.from = NULL; |
6904 | mc.to = NULL; |
6905 | spin_unlock(&mc.lock); |
6906 | mem_cgroup_end_move(from); |
6907 | } |
6908 | |
6909 | static int mem_cgroup_can_attach(struct cgroup_subsys_state *css, |
6910 | struct cgroup_taskset *tset) |
6911 | { |
6912 | struct task_struct *p = cgroup_taskset_first(tset); |
6913 | int ret = 0; |
6914 | struct mem_cgroup *memcg = mem_cgroup_from_css(css); |
6915 | unsigned long move_charge_at_immigrate; |
6916 | |
6917 | /* |
6918 | * We are now commited to this value whatever it is. Changes in this |
6919 | * tunable will only affect upcoming migrations, not the current one. |
6920 | * So we need to save it, and keep it going. |
6921 | */ |
6922 | move_charge_at_immigrate = memcg->move_charge_at_immigrate; |
6923 | if (move_charge_at_immigrate) { |
6924 | struct mm_struct *mm; |
6925 | struct mem_cgroup *from = mem_cgroup_from_task(p); |
6926 | |
6927 | VM_BUG_ON(from == memcg); |
6928 | |
6929 | mm = get_task_mm(p); |
6930 | if (!mm) |
6931 | return 0; |
6932 | /* We move charges only when we move a owner of the mm */ |
6933 | if (mm->owner == p) { |
6934 | VM_BUG_ON(mc.from); |
6935 | VM_BUG_ON(mc.to); |
6936 | VM_BUG_ON(mc.precharge); |
6937 | VM_BUG_ON(mc.moved_charge); |
6938 | VM_BUG_ON(mc.moved_swap); |
6939 | mem_cgroup_start_move(from); |
6940 | spin_lock(&mc.lock); |
6941 | mc.from = from; |
6942 | mc.to = memcg; |
6943 | mc.immigrate_flags = move_charge_at_immigrate; |
6944 | spin_unlock(&mc.lock); |
6945 | /* We set mc.moving_task later */ |
6946 | |
6947 | ret = mem_cgroup_precharge_mc(mm); |
6948 | if (ret) |
6949 | mem_cgroup_clear_mc(); |
6950 | } |
6951 | mmput(mm); |
6952 | } |
6953 | return ret; |
6954 | } |
6955 | |
6956 | static void mem_cgroup_cancel_attach(struct cgroup_subsys_state *css, |
6957 | struct cgroup_taskset *tset) |
6958 | { |
6959 | mem_cgroup_clear_mc(); |
6960 | } |
6961 | |
6962 | static int mem_cgroup_move_charge_pte_range(pmd_t *pmd, |
6963 | unsigned long addr, unsigned long end, |
6964 | struct mm_walk *walk) |
6965 | { |
6966 | int ret = 0; |
6967 | struct vm_area_struct *vma = walk->private; |
6968 | pte_t *pte; |
6969 | spinlock_t *ptl; |
6970 | enum mc_target_type target_type; |
6971 | union mc_target target; |
6972 | struct page *page; |
6973 | struct page_cgroup *pc; |
6974 | |
6975 | /* |
6976 | * We don't take compound_lock() here but no race with splitting thp |
6977 | * happens because: |
6978 | * - if pmd_trans_huge_lock() returns 1, the relevant thp is not |
6979 | * under splitting, which means there's no concurrent thp split, |
6980 | * - if another thread runs into split_huge_page() just after we |
6981 | * entered this if-block, the thread must wait for page table lock |
6982 | * to be unlocked in __split_huge_page_splitting(), where the main |
6983 | * part of thp split is not executed yet. |
6984 | */ |
6985 | if (pmd_trans_huge_lock(pmd, vma, &ptl) == 1) { |
6986 | if (mc.precharge < HPAGE_PMD_NR) { |
6987 | spin_unlock(ptl); |
6988 | return 0; |
6989 | } |
6990 | target_type = get_mctgt_type_thp(vma, addr, *pmd, &target); |
6991 | if (target_type == MC_TARGET_PAGE) { |
6992 | page = target.page; |
6993 | if (!isolate_lru_page(page)) { |
6994 | pc = lookup_page_cgroup(page); |
6995 | if (!mem_cgroup_move_account(page, HPAGE_PMD_NR, |
6996 | pc, mc.from, mc.to)) { |
6997 | mc.precharge -= HPAGE_PMD_NR; |
6998 | mc.moved_charge += HPAGE_PMD_NR; |
6999 | } |
7000 | putback_lru_page(page); |
7001 | } |
7002 | put_page(page); |
7003 | } |
7004 | spin_unlock(ptl); |
7005 | return 0; |
7006 | } |
7007 | |
7008 | if (pmd_trans_unstable(pmd)) |
7009 | return 0; |
7010 | retry: |
7011 | pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); |
7012 | for (; addr != end; addr += PAGE_SIZE) { |
7013 | pte_t ptent = *(pte++); |
7014 | swp_entry_t ent; |
7015 | |
7016 | if (!mc.precharge) |
7017 | break; |
7018 | |
7019 | switch (get_mctgt_type(vma, addr, ptent, &target)) { |
7020 | case MC_TARGET_PAGE: |
7021 | page = target.page; |
7022 | if (isolate_lru_page(page)) |
7023 | goto put; |
7024 | pc = lookup_page_cgroup(page); |
7025 | if (!mem_cgroup_move_account(page, 1, pc, |
7026 | mc.from, mc.to)) { |
7027 | mc.precharge--; |
7028 | /* we uncharge from mc.from later. */ |
7029 | mc.moved_charge++; |
7030 | } |
7031 | putback_lru_page(page); |
7032 | put: /* get_mctgt_type() gets the page */ |
7033 | put_page(page); |
7034 | break; |
7035 | case MC_TARGET_SWAP: |
7036 | ent = target.ent; |
7037 | if (!mem_cgroup_move_swap_account(ent, mc.from, mc.to)) { |
7038 | mc.precharge--; |
7039 | /* we fixup refcnts and charges later. */ |
7040 | mc.moved_swap++; |
7041 | } |
7042 | break; |
7043 | default: |
7044 | break; |
7045 | } |
7046 | } |
7047 | pte_unmap_unlock(pte - 1, ptl); |
7048 | cond_resched(); |
7049 | |
7050 | if (addr != end) { |
7051 | /* |
7052 | * We have consumed all precharges we got in can_attach(). |
7053 | * We try charge one by one, but don't do any additional |
7054 | * charges to mc.to if we have failed in charge once in attach() |
7055 | * phase. |
7056 | */ |
7057 | ret = mem_cgroup_do_precharge(1); |
7058 | if (!ret) |
7059 | goto retry; |
7060 | } |
7061 | |
7062 | return ret; |
7063 | } |
7064 | |
7065 | static void mem_cgroup_move_charge(struct mm_struct *mm) |
7066 | { |
7067 | struct vm_area_struct *vma; |
7068 | |
7069 | lru_add_drain_all(); |
7070 | retry: |
7071 | if (unlikely(!down_read_trylock(&mm->mmap_sem))) { |
7072 | /* |
7073 | * Someone who are holding the mmap_sem might be waiting in |
7074 | * waitq. So we cancel all extra charges, wake up all waiters, |
7075 | * and retry. Because we cancel precharges, we might not be able |
7076 | * to move enough charges, but moving charge is a best-effort |
7077 | * feature anyway, so it wouldn't be a big problem. |
7078 | */ |
7079 | __mem_cgroup_clear_mc(); |
7080 | cond_resched(); |
7081 | goto retry; |
7082 | } |
7083 | for (vma = mm->mmap; vma; vma = vma->vm_next) { |
7084 | int ret; |
7085 | struct mm_walk mem_cgroup_move_charge_walk = { |
7086 | .pmd_entry = mem_cgroup_move_charge_pte_range, |
7087 | .mm = mm, |
7088 | .private = vma, |
7089 | }; |
7090 | if (is_vm_hugetlb_page(vma)) |
7091 | continue; |
7092 | ret = walk_page_range(vma->vm_start, vma->vm_end, |
7093 | &mem_cgroup_move_charge_walk); |
7094 | if (ret) |
7095 | /* |
7096 | * means we have consumed all precharges and failed in |
7097 | * doing additional charge. Just abandon here. |
7098 | */ |
7099 | break; |
7100 | } |
7101 | up_read(&mm->mmap_sem); |
7102 | } |
7103 | |
7104 | static void mem_cgroup_move_task(struct cgroup_subsys_state *css, |
7105 | struct cgroup_taskset *tset) |
7106 | { |
7107 | struct task_struct *p = cgroup_taskset_first(tset); |
7108 | struct mm_struct *mm = get_task_mm(p); |
7109 | |
7110 | if (mm) { |
7111 | if (mc.to) |
7112 | mem_cgroup_move_charge(mm); |
7113 | mmput(mm); |
7114 | } |
7115 | if (mc.to) |
7116 | mem_cgroup_clear_mc(); |
7117 | } |
7118 | #else /* !CONFIG_MMU */ |
7119 | static int mem_cgroup_can_attach(struct cgroup_subsys_state *css, |
7120 | struct cgroup_taskset *tset) |
7121 | { |
7122 | return 0; |
7123 | } |
7124 | static void mem_cgroup_cancel_attach(struct cgroup_subsys_state *css, |
7125 | struct cgroup_taskset *tset) |
7126 | { |
7127 | } |
7128 | static void mem_cgroup_move_task(struct cgroup_subsys_state *css, |
7129 | struct cgroup_taskset *tset) |
7130 | { |
7131 | } |
7132 | #endif |
7133 | |
7134 | /* |
7135 | * Cgroup retains root cgroups across [un]mount cycles making it necessary |
7136 | * to verify sane_behavior flag on each mount attempt. |
7137 | */ |
7138 | static void mem_cgroup_bind(struct cgroup_subsys_state *root_css) |
7139 | { |
7140 | /* |
7141 | * use_hierarchy is forced with sane_behavior. cgroup core |
7142 | * guarantees that @root doesn't have any children, so turning it |
7143 | * on for the root memcg is enough. |
7144 | */ |
7145 | if (cgroup_sane_behavior(root_css->cgroup)) |
7146 | mem_cgroup_from_css(root_css)->use_hierarchy = true; |
7147 | } |
7148 | |
7149 | struct cgroup_subsys memory_cgrp_subsys = { |
7150 | .css_alloc = mem_cgroup_css_alloc, |
7151 | .css_online = mem_cgroup_css_online, |
7152 | .css_offline = mem_cgroup_css_offline, |
7153 | .css_free = mem_cgroup_css_free, |
7154 | .can_attach = mem_cgroup_can_attach, |
7155 | .cancel_attach = mem_cgroup_cancel_attach, |
7156 | .attach = mem_cgroup_move_task, |
7157 | .bind = mem_cgroup_bind, |
7158 | .base_cftypes = mem_cgroup_files, |
7159 | .early_init = 0, |
7160 | }; |
7161 | |
7162 | #ifdef CONFIG_MEMCG_SWAP |
7163 | static int __init enable_swap_account(char *s) |
7164 | { |
7165 | if (!strcmp(s, "1")) |
7166 | really_do_swap_account = 1; |
7167 | else if (!strcmp(s, "0")) |
7168 | really_do_swap_account = 0; |
7169 | return 1; |
7170 | } |
7171 | __setup("swapaccount=", enable_swap_account); |
7172 | |
7173 | static void __init memsw_file_init(void) |
7174 | { |
7175 | WARN_ON(cgroup_add_cftypes(&memory_cgrp_subsys, memsw_cgroup_files)); |
7176 | } |
7177 | |
7178 | static void __init enable_swap_cgroup(void) |
7179 | { |
7180 | if (!mem_cgroup_disabled() && really_do_swap_account) { |
7181 | do_swap_account = 1; |
7182 | memsw_file_init(); |
7183 | } |
7184 | } |
7185 | |
7186 | #else |
7187 | static void __init enable_swap_cgroup(void) |
7188 | { |
7189 | } |
7190 | #endif |
7191 | |
7192 | /* |
7193 | * subsys_initcall() for memory controller. |
7194 | * |
7195 | * Some parts like hotcpu_notifier() have to be initialized from this context |
7196 | * because of lock dependencies (cgroup_lock -> cpu hotplug) but basically |
7197 | * everything that doesn't depend on a specific mem_cgroup structure should |
7198 | * be initialized from here. |
7199 | */ |
7200 | static int __init mem_cgroup_init(void) |
7201 | { |
7202 | hotcpu_notifier(memcg_cpu_hotplug_callback, 0); |
7203 | enable_swap_cgroup(); |
7204 | mem_cgroup_soft_limit_tree_init(); |
7205 | memcg_stock_init(); |
7206 | return 0; |
7207 | } |
7208 | subsys_initcall(mem_cgroup_init); |
7209 |
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