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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 | * This program is free software; you can redistribute it and/or modify |
14 | * it under the terms of the GNU General Public License as published by |
15 | * the Free Software Foundation; either version 2 of the License, or |
16 | * (at your option) any later version. |
17 | * |
18 | * This program is distributed in the hope that it will be useful, |
19 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
20 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
21 | * GNU General Public License for more details. |
22 | */ |
23 | |
24 | #include <linux/res_counter.h> |
25 | #include <linux/memcontrol.h> |
26 | #include <linux/cgroup.h> |
27 | #include <linux/mm.h> |
28 | #include <linux/hugetlb.h> |
29 | #include <linux/pagemap.h> |
30 | #include <linux/smp.h> |
31 | #include <linux/page-flags.h> |
32 | #include <linux/backing-dev.h> |
33 | #include <linux/bit_spinlock.h> |
34 | #include <linux/rcupdate.h> |
35 | #include <linux/limits.h> |
36 | #include <linux/mutex.h> |
37 | #include <linux/rbtree.h> |
38 | #include <linux/slab.h> |
39 | #include <linux/swap.h> |
40 | #include <linux/swapops.h> |
41 | #include <linux/spinlock.h> |
42 | #include <linux/eventfd.h> |
43 | #include <linux/sort.h> |
44 | #include <linux/fs.h> |
45 | #include <linux/seq_file.h> |
46 | #include <linux/vmalloc.h> |
47 | #include <linux/mm_inline.h> |
48 | #include <linux/page_cgroup.h> |
49 | #include <linux/cpu.h> |
50 | #include <linux/oom.h> |
51 | #include "internal.h" |
52 | |
53 | #include <asm/uaccess.h> |
54 | |
55 | #include <trace/events/vmscan.h> |
56 | |
57 | struct cgroup_subsys mem_cgroup_subsys __read_mostly; |
58 | #define MEM_CGROUP_RECLAIM_RETRIES 5 |
59 | struct mem_cgroup *root_mem_cgroup __read_mostly; |
60 | |
61 | #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP |
62 | /* Turned on only when memory cgroup is enabled && really_do_swap_account = 1 */ |
63 | int do_swap_account __read_mostly; |
64 | |
65 | /* for remember boot option*/ |
66 | #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP_ENABLED |
67 | static int really_do_swap_account __initdata = 1; |
68 | #else |
69 | static int really_do_swap_account __initdata = 0; |
70 | #endif |
71 | |
72 | #else |
73 | #define do_swap_account (0) |
74 | #endif |
75 | |
76 | /* |
77 | * Per memcg event counter is incremented at every pagein/pageout. This counter |
78 | * is used for trigger some periodic events. This is straightforward and better |
79 | * than using jiffies etc. to handle periodic memcg event. |
80 | * |
81 | * These values will be used as !((event) & ((1 <<(thresh)) - 1)) |
82 | */ |
83 | #define THRESHOLDS_EVENTS_THRESH (7) /* once in 128 */ |
84 | #define SOFTLIMIT_EVENTS_THRESH (10) /* once in 1024 */ |
85 | |
86 | /* |
87 | * Statistics for memory cgroup. |
88 | */ |
89 | enum mem_cgroup_stat_index { |
90 | /* |
91 | * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss. |
92 | */ |
93 | MEM_CGROUP_STAT_CACHE, /* # of pages charged as cache */ |
94 | MEM_CGROUP_STAT_RSS, /* # of pages charged as anon rss */ |
95 | MEM_CGROUP_STAT_FILE_MAPPED, /* # of pages charged as file rss */ |
96 | MEM_CGROUP_STAT_PGPGIN_COUNT, /* # of pages paged in */ |
97 | MEM_CGROUP_STAT_PGPGOUT_COUNT, /* # of pages paged out */ |
98 | MEM_CGROUP_STAT_SWAPOUT, /* # of pages, swapped out */ |
99 | MEM_CGROUP_STAT_DATA, /* end of data requires synchronization */ |
100 | /* incremented at every pagein/pageout */ |
101 | MEM_CGROUP_EVENTS = MEM_CGROUP_STAT_DATA, |
102 | MEM_CGROUP_ON_MOVE, /* someone is moving account between groups */ |
103 | |
104 | MEM_CGROUP_STAT_NSTATS, |
105 | }; |
106 | |
107 | struct mem_cgroup_stat_cpu { |
108 | s64 count[MEM_CGROUP_STAT_NSTATS]; |
109 | }; |
110 | |
111 | /* |
112 | * per-zone information in memory controller. |
113 | */ |
114 | struct mem_cgroup_per_zone { |
115 | /* |
116 | * spin_lock to protect the per cgroup LRU |
117 | */ |
118 | struct list_head lists[NR_LRU_LISTS]; |
119 | unsigned long count[NR_LRU_LISTS]; |
120 | |
121 | struct zone_reclaim_stat reclaim_stat; |
122 | struct rb_node tree_node; /* RB tree node */ |
123 | unsigned long long usage_in_excess;/* Set to the value by which */ |
124 | /* the soft limit is exceeded*/ |
125 | bool on_tree; |
126 | struct mem_cgroup *mem; /* Back pointer, we cannot */ |
127 | /* use container_of */ |
128 | }; |
129 | /* Macro for accessing counter */ |
130 | #define MEM_CGROUP_ZSTAT(mz, idx) ((mz)->count[(idx)]) |
131 | |
132 | struct mem_cgroup_per_node { |
133 | struct mem_cgroup_per_zone zoneinfo[MAX_NR_ZONES]; |
134 | }; |
135 | |
136 | struct mem_cgroup_lru_info { |
137 | struct mem_cgroup_per_node *nodeinfo[MAX_NUMNODES]; |
138 | }; |
139 | |
140 | /* |
141 | * Cgroups above their limits are maintained in a RB-Tree, independent of |
142 | * their hierarchy representation |
143 | */ |
144 | |
145 | struct mem_cgroup_tree_per_zone { |
146 | struct rb_root rb_root; |
147 | spinlock_t lock; |
148 | }; |
149 | |
150 | struct mem_cgroup_tree_per_node { |
151 | struct mem_cgroup_tree_per_zone rb_tree_per_zone[MAX_NR_ZONES]; |
152 | }; |
153 | |
154 | struct mem_cgroup_tree { |
155 | struct mem_cgroup_tree_per_node *rb_tree_per_node[MAX_NUMNODES]; |
156 | }; |
157 | |
158 | static struct mem_cgroup_tree soft_limit_tree __read_mostly; |
159 | |
160 | struct mem_cgroup_threshold { |
161 | struct eventfd_ctx *eventfd; |
162 | u64 threshold; |
163 | }; |
164 | |
165 | /* For threshold */ |
166 | struct mem_cgroup_threshold_ary { |
167 | /* An array index points to threshold just below usage. */ |
168 | int current_threshold; |
169 | /* Size of entries[] */ |
170 | unsigned int size; |
171 | /* Array of thresholds */ |
172 | struct mem_cgroup_threshold entries[0]; |
173 | }; |
174 | |
175 | struct mem_cgroup_thresholds { |
176 | /* Primary thresholds array */ |
177 | struct mem_cgroup_threshold_ary *primary; |
178 | /* |
179 | * Spare threshold array. |
180 | * This is needed to make mem_cgroup_unregister_event() "never fail". |
181 | * It must be able to store at least primary->size - 1 entries. |
182 | */ |
183 | struct mem_cgroup_threshold_ary *spare; |
184 | }; |
185 | |
186 | /* for OOM */ |
187 | struct mem_cgroup_eventfd_list { |
188 | struct list_head list; |
189 | struct eventfd_ctx *eventfd; |
190 | }; |
191 | |
192 | static void mem_cgroup_threshold(struct mem_cgroup *mem); |
193 | static void mem_cgroup_oom_notify(struct mem_cgroup *mem); |
194 | |
195 | /* |
196 | * The memory controller data structure. The memory controller controls both |
197 | * page cache and RSS per cgroup. We would eventually like to provide |
198 | * statistics based on the statistics developed by Rik Van Riel for clock-pro, |
199 | * to help the administrator determine what knobs to tune. |
200 | * |
201 | * TODO: Add a water mark for the memory controller. Reclaim will begin when |
202 | * we hit the water mark. May be even add a low water mark, such that |
203 | * no reclaim occurs from a cgroup at it's low water mark, this is |
204 | * a feature that will be implemented much later in the future. |
205 | */ |
206 | struct mem_cgroup { |
207 | struct cgroup_subsys_state css; |
208 | /* |
209 | * the counter to account for memory usage |
210 | */ |
211 | struct res_counter res; |
212 | /* |
213 | * the counter to account for mem+swap usage. |
214 | */ |
215 | struct res_counter memsw; |
216 | /* |
217 | * Per cgroup active and inactive list, similar to the |
218 | * per zone LRU lists. |
219 | */ |
220 | struct mem_cgroup_lru_info info; |
221 | |
222 | /* |
223 | protect against reclaim related member. |
224 | */ |
225 | spinlock_t reclaim_param_lock; |
226 | |
227 | /* |
228 | * While reclaiming in a hierarchy, we cache the last child we |
229 | * reclaimed from. |
230 | */ |
231 | int last_scanned_child; |
232 | /* |
233 | * Should the accounting and control be hierarchical, per subtree? |
234 | */ |
235 | bool use_hierarchy; |
236 | atomic_t oom_lock; |
237 | atomic_t refcnt; |
238 | |
239 | unsigned int swappiness; |
240 | /* OOM-Killer disable */ |
241 | int oom_kill_disable; |
242 | |
243 | /* set when res.limit == memsw.limit */ |
244 | bool memsw_is_minimum; |
245 | |
246 | /* protect arrays of thresholds */ |
247 | struct mutex thresholds_lock; |
248 | |
249 | /* thresholds for memory usage. RCU-protected */ |
250 | struct mem_cgroup_thresholds thresholds; |
251 | |
252 | /* thresholds for mem+swap usage. RCU-protected */ |
253 | struct mem_cgroup_thresholds memsw_thresholds; |
254 | |
255 | /* For oom notifier event fd */ |
256 | struct list_head oom_notify; |
257 | |
258 | /* |
259 | * Should we move charges of a task when a task is moved into this |
260 | * mem_cgroup ? And what type of charges should we move ? |
261 | */ |
262 | unsigned long move_charge_at_immigrate; |
263 | /* |
264 | * percpu counter. |
265 | */ |
266 | struct mem_cgroup_stat_cpu *stat; |
267 | /* |
268 | * used when a cpu is offlined or other synchronizations |
269 | * See mem_cgroup_read_stat(). |
270 | */ |
271 | struct mem_cgroup_stat_cpu nocpu_base; |
272 | spinlock_t pcp_counter_lock; |
273 | }; |
274 | |
275 | /* Stuffs for move charges at task migration. */ |
276 | /* |
277 | * Types of charges to be moved. "move_charge_at_immitgrate" is treated as a |
278 | * left-shifted bitmap of these types. |
279 | */ |
280 | enum move_type { |
281 | MOVE_CHARGE_TYPE_ANON, /* private anonymous page and swap of it */ |
282 | MOVE_CHARGE_TYPE_FILE, /* file page(including tmpfs) and swap of it */ |
283 | NR_MOVE_TYPE, |
284 | }; |
285 | |
286 | /* "mc" and its members are protected by cgroup_mutex */ |
287 | static struct move_charge_struct { |
288 | spinlock_t lock; /* for from, to */ |
289 | struct mem_cgroup *from; |
290 | struct mem_cgroup *to; |
291 | unsigned long precharge; |
292 | unsigned long moved_charge; |
293 | unsigned long moved_swap; |
294 | struct task_struct *moving_task; /* a task moving charges */ |
295 | wait_queue_head_t waitq; /* a waitq for other context */ |
296 | } mc = { |
297 | .lock = __SPIN_LOCK_UNLOCKED(mc.lock), |
298 | .waitq = __WAIT_QUEUE_HEAD_INITIALIZER(mc.waitq), |
299 | }; |
300 | |
301 | static bool move_anon(void) |
302 | { |
303 | return test_bit(MOVE_CHARGE_TYPE_ANON, |
304 | &mc.to->move_charge_at_immigrate); |
305 | } |
306 | |
307 | static bool move_file(void) |
308 | { |
309 | return test_bit(MOVE_CHARGE_TYPE_FILE, |
310 | &mc.to->move_charge_at_immigrate); |
311 | } |
312 | |
313 | /* |
314 | * Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft |
315 | * limit reclaim to prevent infinite loops, if they ever occur. |
316 | */ |
317 | #define MEM_CGROUP_MAX_RECLAIM_LOOPS (100) |
318 | #define MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS (2) |
319 | |
320 | enum charge_type { |
321 | MEM_CGROUP_CHARGE_TYPE_CACHE = 0, |
322 | MEM_CGROUP_CHARGE_TYPE_MAPPED, |
323 | MEM_CGROUP_CHARGE_TYPE_SHMEM, /* used by page migration of shmem */ |
324 | MEM_CGROUP_CHARGE_TYPE_FORCE, /* used by force_empty */ |
325 | MEM_CGROUP_CHARGE_TYPE_SWAPOUT, /* for accounting swapcache */ |
326 | MEM_CGROUP_CHARGE_TYPE_DROP, /* a page was unused swap cache */ |
327 | NR_CHARGE_TYPE, |
328 | }; |
329 | |
330 | /* only for here (for easy reading.) */ |
331 | #define PCGF_CACHE (1UL << PCG_CACHE) |
332 | #define PCGF_USED (1UL << PCG_USED) |
333 | #define PCGF_LOCK (1UL << PCG_LOCK) |
334 | /* Not used, but added here for completeness */ |
335 | #define PCGF_ACCT (1UL << PCG_ACCT) |
336 | |
337 | /* for encoding cft->private value on file */ |
338 | #define _MEM (0) |
339 | #define _MEMSWAP (1) |
340 | #define _OOM_TYPE (2) |
341 | #define MEMFILE_PRIVATE(x, val) (((x) << 16) | (val)) |
342 | #define MEMFILE_TYPE(val) (((val) >> 16) & 0xffff) |
343 | #define MEMFILE_ATTR(val) ((val) & 0xffff) |
344 | /* Used for OOM nofiier */ |
345 | #define OOM_CONTROL (0) |
346 | |
347 | /* |
348 | * Reclaim flags for mem_cgroup_hierarchical_reclaim |
349 | */ |
350 | #define MEM_CGROUP_RECLAIM_NOSWAP_BIT 0x0 |
351 | #define MEM_CGROUP_RECLAIM_NOSWAP (1 << MEM_CGROUP_RECLAIM_NOSWAP_BIT) |
352 | #define MEM_CGROUP_RECLAIM_SHRINK_BIT 0x1 |
353 | #define MEM_CGROUP_RECLAIM_SHRINK (1 << MEM_CGROUP_RECLAIM_SHRINK_BIT) |
354 | #define MEM_CGROUP_RECLAIM_SOFT_BIT 0x2 |
355 | #define MEM_CGROUP_RECLAIM_SOFT (1 << MEM_CGROUP_RECLAIM_SOFT_BIT) |
356 | |
357 | static void mem_cgroup_get(struct mem_cgroup *mem); |
358 | static void mem_cgroup_put(struct mem_cgroup *mem); |
359 | static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem); |
360 | static void drain_all_stock_async(void); |
361 | |
362 | static struct mem_cgroup_per_zone * |
363 | mem_cgroup_zoneinfo(struct mem_cgroup *mem, int nid, int zid) |
364 | { |
365 | return &mem->info.nodeinfo[nid]->zoneinfo[zid]; |
366 | } |
367 | |
368 | struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *mem) |
369 | { |
370 | return &mem->css; |
371 | } |
372 | |
373 | static struct mem_cgroup_per_zone * |
374 | page_cgroup_zoneinfo(struct page_cgroup *pc) |
375 | { |
376 | struct mem_cgroup *mem = pc->mem_cgroup; |
377 | int nid = page_cgroup_nid(pc); |
378 | int zid = page_cgroup_zid(pc); |
379 | |
380 | if (!mem) |
381 | return NULL; |
382 | |
383 | return mem_cgroup_zoneinfo(mem, nid, zid); |
384 | } |
385 | |
386 | static struct mem_cgroup_tree_per_zone * |
387 | soft_limit_tree_node_zone(int nid, int zid) |
388 | { |
389 | return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid]; |
390 | } |
391 | |
392 | static struct mem_cgroup_tree_per_zone * |
393 | soft_limit_tree_from_page(struct page *page) |
394 | { |
395 | int nid = page_to_nid(page); |
396 | int zid = page_zonenum(page); |
397 | |
398 | return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid]; |
399 | } |
400 | |
401 | static void |
402 | __mem_cgroup_insert_exceeded(struct mem_cgroup *mem, |
403 | struct mem_cgroup_per_zone *mz, |
404 | struct mem_cgroup_tree_per_zone *mctz, |
405 | unsigned long long new_usage_in_excess) |
406 | { |
407 | struct rb_node **p = &mctz->rb_root.rb_node; |
408 | struct rb_node *parent = NULL; |
409 | struct mem_cgroup_per_zone *mz_node; |
410 | |
411 | if (mz->on_tree) |
412 | return; |
413 | |
414 | mz->usage_in_excess = new_usage_in_excess; |
415 | if (!mz->usage_in_excess) |
416 | return; |
417 | while (*p) { |
418 | parent = *p; |
419 | mz_node = rb_entry(parent, struct mem_cgroup_per_zone, |
420 | tree_node); |
421 | if (mz->usage_in_excess < mz_node->usage_in_excess) |
422 | p = &(*p)->rb_left; |
423 | /* |
424 | * We can't avoid mem cgroups that are over their soft |
425 | * limit by the same amount |
426 | */ |
427 | else if (mz->usage_in_excess >= mz_node->usage_in_excess) |
428 | p = &(*p)->rb_right; |
429 | } |
430 | rb_link_node(&mz->tree_node, parent, p); |
431 | rb_insert_color(&mz->tree_node, &mctz->rb_root); |
432 | mz->on_tree = true; |
433 | } |
434 | |
435 | static void |
436 | __mem_cgroup_remove_exceeded(struct mem_cgroup *mem, |
437 | struct mem_cgroup_per_zone *mz, |
438 | struct mem_cgroup_tree_per_zone *mctz) |
439 | { |
440 | if (!mz->on_tree) |
441 | return; |
442 | rb_erase(&mz->tree_node, &mctz->rb_root); |
443 | mz->on_tree = false; |
444 | } |
445 | |
446 | static void |
447 | mem_cgroup_remove_exceeded(struct mem_cgroup *mem, |
448 | struct mem_cgroup_per_zone *mz, |
449 | struct mem_cgroup_tree_per_zone *mctz) |
450 | { |
451 | spin_lock(&mctz->lock); |
452 | __mem_cgroup_remove_exceeded(mem, mz, mctz); |
453 | spin_unlock(&mctz->lock); |
454 | } |
455 | |
456 | |
457 | static void mem_cgroup_update_tree(struct mem_cgroup *mem, struct page *page) |
458 | { |
459 | unsigned long long excess; |
460 | struct mem_cgroup_per_zone *mz; |
461 | struct mem_cgroup_tree_per_zone *mctz; |
462 | int nid = page_to_nid(page); |
463 | int zid = page_zonenum(page); |
464 | mctz = soft_limit_tree_from_page(page); |
465 | |
466 | /* |
467 | * Necessary to update all ancestors when hierarchy is used. |
468 | * because their event counter is not touched. |
469 | */ |
470 | for (; mem; mem = parent_mem_cgroup(mem)) { |
471 | mz = mem_cgroup_zoneinfo(mem, nid, zid); |
472 | excess = res_counter_soft_limit_excess(&mem->res); |
473 | /* |
474 | * We have to update the tree if mz is on RB-tree or |
475 | * mem is over its softlimit. |
476 | */ |
477 | if (excess || mz->on_tree) { |
478 | spin_lock(&mctz->lock); |
479 | /* if on-tree, remove it */ |
480 | if (mz->on_tree) |
481 | __mem_cgroup_remove_exceeded(mem, mz, mctz); |
482 | /* |
483 | * Insert again. mz->usage_in_excess will be updated. |
484 | * If excess is 0, no tree ops. |
485 | */ |
486 | __mem_cgroup_insert_exceeded(mem, mz, mctz, excess); |
487 | spin_unlock(&mctz->lock); |
488 | } |
489 | } |
490 | } |
491 | |
492 | static void mem_cgroup_remove_from_trees(struct mem_cgroup *mem) |
493 | { |
494 | int node, zone; |
495 | struct mem_cgroup_per_zone *mz; |
496 | struct mem_cgroup_tree_per_zone *mctz; |
497 | |
498 | for_each_node_state(node, N_POSSIBLE) { |
499 | for (zone = 0; zone < MAX_NR_ZONES; zone++) { |
500 | mz = mem_cgroup_zoneinfo(mem, node, zone); |
501 | mctz = soft_limit_tree_node_zone(node, zone); |
502 | mem_cgroup_remove_exceeded(mem, mz, mctz); |
503 | } |
504 | } |
505 | } |
506 | |
507 | static inline unsigned long mem_cgroup_get_excess(struct mem_cgroup *mem) |
508 | { |
509 | return res_counter_soft_limit_excess(&mem->res) >> PAGE_SHIFT; |
510 | } |
511 | |
512 | static struct mem_cgroup_per_zone * |
513 | __mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz) |
514 | { |
515 | struct rb_node *rightmost = NULL; |
516 | struct mem_cgroup_per_zone *mz; |
517 | |
518 | retry: |
519 | mz = NULL; |
520 | rightmost = rb_last(&mctz->rb_root); |
521 | if (!rightmost) |
522 | goto done; /* Nothing to reclaim from */ |
523 | |
524 | mz = rb_entry(rightmost, struct mem_cgroup_per_zone, tree_node); |
525 | /* |
526 | * Remove the node now but someone else can add it back, |
527 | * we will to add it back at the end of reclaim to its correct |
528 | * position in the tree. |
529 | */ |
530 | __mem_cgroup_remove_exceeded(mz->mem, mz, mctz); |
531 | if (!res_counter_soft_limit_excess(&mz->mem->res) || |
532 | !css_tryget(&mz->mem->css)) |
533 | goto retry; |
534 | done: |
535 | return mz; |
536 | } |
537 | |
538 | static struct mem_cgroup_per_zone * |
539 | mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz) |
540 | { |
541 | struct mem_cgroup_per_zone *mz; |
542 | |
543 | spin_lock(&mctz->lock); |
544 | mz = __mem_cgroup_largest_soft_limit_node(mctz); |
545 | spin_unlock(&mctz->lock); |
546 | return mz; |
547 | } |
548 | |
549 | /* |
550 | * Implementation Note: reading percpu statistics for memcg. |
551 | * |
552 | * Both of vmstat[] and percpu_counter has threshold and do periodic |
553 | * synchronization to implement "quick" read. There are trade-off between |
554 | * reading cost and precision of value. Then, we may have a chance to implement |
555 | * a periodic synchronizion of counter in memcg's counter. |
556 | * |
557 | * But this _read() function is used for user interface now. The user accounts |
558 | * memory usage by memory cgroup and he _always_ requires exact value because |
559 | * he accounts memory. Even if we provide quick-and-fuzzy read, we always |
560 | * have to visit all online cpus and make sum. So, for now, unnecessary |
561 | * synchronization is not implemented. (just implemented for cpu hotplug) |
562 | * |
563 | * If there are kernel internal actions which can make use of some not-exact |
564 | * value, and reading all cpu value can be performance bottleneck in some |
565 | * common workload, threashold and synchonization as vmstat[] should be |
566 | * implemented. |
567 | */ |
568 | static s64 mem_cgroup_read_stat(struct mem_cgroup *mem, |
569 | enum mem_cgroup_stat_index idx) |
570 | { |
571 | int cpu; |
572 | s64 val = 0; |
573 | |
574 | get_online_cpus(); |
575 | for_each_online_cpu(cpu) |
576 | val += per_cpu(mem->stat->count[idx], cpu); |
577 | #ifdef CONFIG_HOTPLUG_CPU |
578 | spin_lock(&mem->pcp_counter_lock); |
579 | val += mem->nocpu_base.count[idx]; |
580 | spin_unlock(&mem->pcp_counter_lock); |
581 | #endif |
582 | put_online_cpus(); |
583 | return val; |
584 | } |
585 | |
586 | static s64 mem_cgroup_local_usage(struct mem_cgroup *mem) |
587 | { |
588 | s64 ret; |
589 | |
590 | ret = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_RSS); |
591 | ret += mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_CACHE); |
592 | return ret; |
593 | } |
594 | |
595 | static void mem_cgroup_swap_statistics(struct mem_cgroup *mem, |
596 | bool charge) |
597 | { |
598 | int val = (charge) ? 1 : -1; |
599 | this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_SWAPOUT], val); |
600 | } |
601 | |
602 | static void mem_cgroup_charge_statistics(struct mem_cgroup *mem, |
603 | bool file, int nr_pages) |
604 | { |
605 | preempt_disable(); |
606 | |
607 | if (file) |
608 | __this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_CACHE], nr_pages); |
609 | else |
610 | __this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_RSS], nr_pages); |
611 | |
612 | /* pagein of a big page is an event. So, ignore page size */ |
613 | if (nr_pages > 0) |
614 | __this_cpu_inc(mem->stat->count[MEM_CGROUP_STAT_PGPGIN_COUNT]); |
615 | else { |
616 | __this_cpu_inc(mem->stat->count[MEM_CGROUP_STAT_PGPGOUT_COUNT]); |
617 | nr_pages = -nr_pages; /* for event */ |
618 | } |
619 | |
620 | __this_cpu_add(mem->stat->count[MEM_CGROUP_EVENTS], nr_pages); |
621 | |
622 | preempt_enable(); |
623 | } |
624 | |
625 | static unsigned long mem_cgroup_get_local_zonestat(struct mem_cgroup *mem, |
626 | enum lru_list idx) |
627 | { |
628 | int nid, zid; |
629 | struct mem_cgroup_per_zone *mz; |
630 | u64 total = 0; |
631 | |
632 | for_each_online_node(nid) |
633 | for (zid = 0; zid < MAX_NR_ZONES; zid++) { |
634 | mz = mem_cgroup_zoneinfo(mem, nid, zid); |
635 | total += MEM_CGROUP_ZSTAT(mz, idx); |
636 | } |
637 | return total; |
638 | } |
639 | |
640 | static bool __memcg_event_check(struct mem_cgroup *mem, int event_mask_shift) |
641 | { |
642 | s64 val; |
643 | |
644 | val = this_cpu_read(mem->stat->count[MEM_CGROUP_EVENTS]); |
645 | |
646 | return !(val & ((1 << event_mask_shift) - 1)); |
647 | } |
648 | |
649 | /* |
650 | * Check events in order. |
651 | * |
652 | */ |
653 | static void memcg_check_events(struct mem_cgroup *mem, struct page *page) |
654 | { |
655 | /* threshold event is triggered in finer grain than soft limit */ |
656 | if (unlikely(__memcg_event_check(mem, THRESHOLDS_EVENTS_THRESH))) { |
657 | mem_cgroup_threshold(mem); |
658 | if (unlikely(__memcg_event_check(mem, SOFTLIMIT_EVENTS_THRESH))) |
659 | mem_cgroup_update_tree(mem, page); |
660 | } |
661 | } |
662 | |
663 | static struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont) |
664 | { |
665 | return container_of(cgroup_subsys_state(cont, |
666 | mem_cgroup_subsys_id), struct mem_cgroup, |
667 | css); |
668 | } |
669 | |
670 | struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p) |
671 | { |
672 | /* |
673 | * mm_update_next_owner() may clear mm->owner to NULL |
674 | * if it races with swapoff, page migration, etc. |
675 | * So this can be called with p == NULL. |
676 | */ |
677 | if (unlikely(!p)) |
678 | return NULL; |
679 | |
680 | return container_of(task_subsys_state(p, mem_cgroup_subsys_id), |
681 | struct mem_cgroup, css); |
682 | } |
683 | |
684 | static struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm) |
685 | { |
686 | struct mem_cgroup *mem = NULL; |
687 | |
688 | if (!mm) |
689 | return NULL; |
690 | /* |
691 | * Because we have no locks, mm->owner's may be being moved to other |
692 | * cgroup. We use css_tryget() here even if this looks |
693 | * pessimistic (rather than adding locks here). |
694 | */ |
695 | rcu_read_lock(); |
696 | do { |
697 | mem = mem_cgroup_from_task(rcu_dereference(mm->owner)); |
698 | if (unlikely(!mem)) |
699 | break; |
700 | } while (!css_tryget(&mem->css)); |
701 | rcu_read_unlock(); |
702 | return mem; |
703 | } |
704 | |
705 | /* The caller has to guarantee "mem" exists before calling this */ |
706 | static struct mem_cgroup *mem_cgroup_start_loop(struct mem_cgroup *mem) |
707 | { |
708 | struct cgroup_subsys_state *css; |
709 | int found; |
710 | |
711 | if (!mem) /* ROOT cgroup has the smallest ID */ |
712 | return root_mem_cgroup; /*css_put/get against root is ignored*/ |
713 | if (!mem->use_hierarchy) { |
714 | if (css_tryget(&mem->css)) |
715 | return mem; |
716 | return NULL; |
717 | } |
718 | rcu_read_lock(); |
719 | /* |
720 | * searching a memory cgroup which has the smallest ID under given |
721 | * ROOT cgroup. (ID >= 1) |
722 | */ |
723 | css = css_get_next(&mem_cgroup_subsys, 1, &mem->css, &found); |
724 | if (css && css_tryget(css)) |
725 | mem = container_of(css, struct mem_cgroup, css); |
726 | else |
727 | mem = NULL; |
728 | rcu_read_unlock(); |
729 | return mem; |
730 | } |
731 | |
732 | static struct mem_cgroup *mem_cgroup_get_next(struct mem_cgroup *iter, |
733 | struct mem_cgroup *root, |
734 | bool cond) |
735 | { |
736 | int nextid = css_id(&iter->css) + 1; |
737 | int found; |
738 | int hierarchy_used; |
739 | struct cgroup_subsys_state *css; |
740 | |
741 | hierarchy_used = iter->use_hierarchy; |
742 | |
743 | css_put(&iter->css); |
744 | /* If no ROOT, walk all, ignore hierarchy */ |
745 | if (!cond || (root && !hierarchy_used)) |
746 | return NULL; |
747 | |
748 | if (!root) |
749 | root = root_mem_cgroup; |
750 | |
751 | do { |
752 | iter = NULL; |
753 | rcu_read_lock(); |
754 | |
755 | css = css_get_next(&mem_cgroup_subsys, nextid, |
756 | &root->css, &found); |
757 | if (css && css_tryget(css)) |
758 | iter = container_of(css, struct mem_cgroup, css); |
759 | rcu_read_unlock(); |
760 | /* If css is NULL, no more cgroups will be found */ |
761 | nextid = found + 1; |
762 | } while (css && !iter); |
763 | |
764 | return iter; |
765 | } |
766 | /* |
767 | * for_eacn_mem_cgroup_tree() for visiting all cgroup under tree. Please |
768 | * be careful that "break" loop is not allowed. We have reference count. |
769 | * Instead of that modify "cond" to be false and "continue" to exit the loop. |
770 | */ |
771 | #define for_each_mem_cgroup_tree_cond(iter, root, cond) \ |
772 | for (iter = mem_cgroup_start_loop(root);\ |
773 | iter != NULL;\ |
774 | iter = mem_cgroup_get_next(iter, root, cond)) |
775 | |
776 | #define for_each_mem_cgroup_tree(iter, root) \ |
777 | for_each_mem_cgroup_tree_cond(iter, root, true) |
778 | |
779 | #define for_each_mem_cgroup_all(iter) \ |
780 | for_each_mem_cgroup_tree_cond(iter, NULL, true) |
781 | |
782 | |
783 | static inline bool mem_cgroup_is_root(struct mem_cgroup *mem) |
784 | { |
785 | return (mem == root_mem_cgroup); |
786 | } |
787 | |
788 | /* |
789 | * Following LRU functions are allowed to be used without PCG_LOCK. |
790 | * Operations are called by routine of global LRU independently from memcg. |
791 | * What we have to take care of here is validness of pc->mem_cgroup. |
792 | * |
793 | * Changes to pc->mem_cgroup happens when |
794 | * 1. charge |
795 | * 2. moving account |
796 | * In typical case, "charge" is done before add-to-lru. Exception is SwapCache. |
797 | * It is added to LRU before charge. |
798 | * If PCG_USED bit is not set, page_cgroup is not added to this private LRU. |
799 | * When moving account, the page is not on LRU. It's isolated. |
800 | */ |
801 | |
802 | void mem_cgroup_del_lru_list(struct page *page, enum lru_list lru) |
803 | { |
804 | struct page_cgroup *pc; |
805 | struct mem_cgroup_per_zone *mz; |
806 | |
807 | if (mem_cgroup_disabled()) |
808 | return; |
809 | pc = lookup_page_cgroup(page); |
810 | /* can happen while we handle swapcache. */ |
811 | if (!TestClearPageCgroupAcctLRU(pc)) |
812 | return; |
813 | VM_BUG_ON(!pc->mem_cgroup); |
814 | /* |
815 | * We don't check PCG_USED bit. It's cleared when the "page" is finally |
816 | * removed from global LRU. |
817 | */ |
818 | mz = page_cgroup_zoneinfo(pc); |
819 | /* huge page split is done under lru_lock. so, we have no races. */ |
820 | MEM_CGROUP_ZSTAT(mz, lru) -= 1 << compound_order(page); |
821 | if (mem_cgroup_is_root(pc->mem_cgroup)) |
822 | return; |
823 | VM_BUG_ON(list_empty(&pc->lru)); |
824 | list_del_init(&pc->lru); |
825 | } |
826 | |
827 | void mem_cgroup_del_lru(struct page *page) |
828 | { |
829 | mem_cgroup_del_lru_list(page, page_lru(page)); |
830 | } |
831 | |
832 | void mem_cgroup_rotate_lru_list(struct page *page, enum lru_list lru) |
833 | { |
834 | struct mem_cgroup_per_zone *mz; |
835 | struct page_cgroup *pc; |
836 | |
837 | if (mem_cgroup_disabled()) |
838 | return; |
839 | |
840 | pc = lookup_page_cgroup(page); |
841 | /* unused or root page is not rotated. */ |
842 | if (!PageCgroupUsed(pc)) |
843 | return; |
844 | /* Ensure pc->mem_cgroup is visible after reading PCG_USED. */ |
845 | smp_rmb(); |
846 | if (mem_cgroup_is_root(pc->mem_cgroup)) |
847 | return; |
848 | mz = page_cgroup_zoneinfo(pc); |
849 | list_move(&pc->lru, &mz->lists[lru]); |
850 | } |
851 | |
852 | void mem_cgroup_add_lru_list(struct page *page, enum lru_list lru) |
853 | { |
854 | struct page_cgroup *pc; |
855 | struct mem_cgroup_per_zone *mz; |
856 | |
857 | if (mem_cgroup_disabled()) |
858 | return; |
859 | pc = lookup_page_cgroup(page); |
860 | VM_BUG_ON(PageCgroupAcctLRU(pc)); |
861 | if (!PageCgroupUsed(pc)) |
862 | return; |
863 | /* Ensure pc->mem_cgroup is visible after reading PCG_USED. */ |
864 | smp_rmb(); |
865 | mz = page_cgroup_zoneinfo(pc); |
866 | /* huge page split is done under lru_lock. so, we have no races. */ |
867 | MEM_CGROUP_ZSTAT(mz, lru) += 1 << compound_order(page); |
868 | SetPageCgroupAcctLRU(pc); |
869 | if (mem_cgroup_is_root(pc->mem_cgroup)) |
870 | return; |
871 | list_add(&pc->lru, &mz->lists[lru]); |
872 | } |
873 | |
874 | /* |
875 | * At handling SwapCache, pc->mem_cgroup may be changed while it's linked to |
876 | * lru because the page may.be reused after it's fully uncharged (because of |
877 | * SwapCache behavior).To handle that, unlink page_cgroup from LRU when charge |
878 | * it again. This function is only used to charge SwapCache. It's done under |
879 | * lock_page and expected that zone->lru_lock is never held. |
880 | */ |
881 | static void mem_cgroup_lru_del_before_commit_swapcache(struct page *page) |
882 | { |
883 | unsigned long flags; |
884 | struct zone *zone = page_zone(page); |
885 | struct page_cgroup *pc = lookup_page_cgroup(page); |
886 | |
887 | spin_lock_irqsave(&zone->lru_lock, flags); |
888 | /* |
889 | * Forget old LRU when this page_cgroup is *not* used. This Used bit |
890 | * is guarded by lock_page() because the page is SwapCache. |
891 | */ |
892 | if (!PageCgroupUsed(pc)) |
893 | mem_cgroup_del_lru_list(page, page_lru(page)); |
894 | spin_unlock_irqrestore(&zone->lru_lock, flags); |
895 | } |
896 | |
897 | static void mem_cgroup_lru_add_after_commit_swapcache(struct page *page) |
898 | { |
899 | unsigned long flags; |
900 | struct zone *zone = page_zone(page); |
901 | struct page_cgroup *pc = lookup_page_cgroup(page); |
902 | |
903 | spin_lock_irqsave(&zone->lru_lock, flags); |
904 | /* link when the page is linked to LRU but page_cgroup isn't */ |
905 | if (PageLRU(page) && !PageCgroupAcctLRU(pc)) |
906 | mem_cgroup_add_lru_list(page, page_lru(page)); |
907 | spin_unlock_irqrestore(&zone->lru_lock, flags); |
908 | } |
909 | |
910 | |
911 | void mem_cgroup_move_lists(struct page *page, |
912 | enum lru_list from, enum lru_list to) |
913 | { |
914 | if (mem_cgroup_disabled()) |
915 | return; |
916 | mem_cgroup_del_lru_list(page, from); |
917 | mem_cgroup_add_lru_list(page, to); |
918 | } |
919 | |
920 | int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem) |
921 | { |
922 | int ret; |
923 | struct mem_cgroup *curr = NULL; |
924 | struct task_struct *p; |
925 | |
926 | p = find_lock_task_mm(task); |
927 | if (!p) |
928 | return 0; |
929 | curr = try_get_mem_cgroup_from_mm(p->mm); |
930 | task_unlock(p); |
931 | if (!curr) |
932 | return 0; |
933 | /* |
934 | * We should check use_hierarchy of "mem" not "curr". Because checking |
935 | * use_hierarchy of "curr" here make this function true if hierarchy is |
936 | * enabled in "curr" and "curr" is a child of "mem" in *cgroup* |
937 | * hierarchy(even if use_hierarchy is disabled in "mem"). |
938 | */ |
939 | if (mem->use_hierarchy) |
940 | ret = css_is_ancestor(&curr->css, &mem->css); |
941 | else |
942 | ret = (curr == mem); |
943 | css_put(&curr->css); |
944 | return ret; |
945 | } |
946 | |
947 | static int calc_inactive_ratio(struct mem_cgroup *memcg, unsigned long *present_pages) |
948 | { |
949 | unsigned long active; |
950 | unsigned long inactive; |
951 | unsigned long gb; |
952 | unsigned long inactive_ratio; |
953 | |
954 | inactive = mem_cgroup_get_local_zonestat(memcg, LRU_INACTIVE_ANON); |
955 | active = mem_cgroup_get_local_zonestat(memcg, LRU_ACTIVE_ANON); |
956 | |
957 | gb = (inactive + active) >> (30 - PAGE_SHIFT); |
958 | if (gb) |
959 | inactive_ratio = int_sqrt(10 * gb); |
960 | else |
961 | inactive_ratio = 1; |
962 | |
963 | if (present_pages) { |
964 | present_pages[0] = inactive; |
965 | present_pages[1] = active; |
966 | } |
967 | |
968 | return inactive_ratio; |
969 | } |
970 | |
971 | int mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg) |
972 | { |
973 | unsigned long active; |
974 | unsigned long inactive; |
975 | unsigned long present_pages[2]; |
976 | unsigned long inactive_ratio; |
977 | |
978 | inactive_ratio = calc_inactive_ratio(memcg, present_pages); |
979 | |
980 | inactive = present_pages[0]; |
981 | active = present_pages[1]; |
982 | |
983 | if (inactive * inactive_ratio < active) |
984 | return 1; |
985 | |
986 | return 0; |
987 | } |
988 | |
989 | int mem_cgroup_inactive_file_is_low(struct mem_cgroup *memcg) |
990 | { |
991 | unsigned long active; |
992 | unsigned long inactive; |
993 | |
994 | inactive = mem_cgroup_get_local_zonestat(memcg, LRU_INACTIVE_FILE); |
995 | active = mem_cgroup_get_local_zonestat(memcg, LRU_ACTIVE_FILE); |
996 | |
997 | return (active > inactive); |
998 | } |
999 | |
1000 | unsigned long mem_cgroup_zone_nr_pages(struct mem_cgroup *memcg, |
1001 | struct zone *zone, |
1002 | enum lru_list lru) |
1003 | { |
1004 | int nid = zone_to_nid(zone); |
1005 | int zid = zone_idx(zone); |
1006 | struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid); |
1007 | |
1008 | return MEM_CGROUP_ZSTAT(mz, lru); |
1009 | } |
1010 | |
1011 | struct zone_reclaim_stat *mem_cgroup_get_reclaim_stat(struct mem_cgroup *memcg, |
1012 | struct zone *zone) |
1013 | { |
1014 | int nid = zone_to_nid(zone); |
1015 | int zid = zone_idx(zone); |
1016 | struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid); |
1017 | |
1018 | return &mz->reclaim_stat; |
1019 | } |
1020 | |
1021 | struct zone_reclaim_stat * |
1022 | mem_cgroup_get_reclaim_stat_from_page(struct page *page) |
1023 | { |
1024 | struct page_cgroup *pc; |
1025 | struct mem_cgroup_per_zone *mz; |
1026 | |
1027 | if (mem_cgroup_disabled()) |
1028 | return NULL; |
1029 | |
1030 | pc = lookup_page_cgroup(page); |
1031 | if (!PageCgroupUsed(pc)) |
1032 | return NULL; |
1033 | /* Ensure pc->mem_cgroup is visible after reading PCG_USED. */ |
1034 | smp_rmb(); |
1035 | mz = page_cgroup_zoneinfo(pc); |
1036 | if (!mz) |
1037 | return NULL; |
1038 | |
1039 | return &mz->reclaim_stat; |
1040 | } |
1041 | |
1042 | unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan, |
1043 | struct list_head *dst, |
1044 | unsigned long *scanned, int order, |
1045 | int mode, struct zone *z, |
1046 | struct mem_cgroup *mem_cont, |
1047 | int active, int file) |
1048 | { |
1049 | unsigned long nr_taken = 0; |
1050 | struct page *page; |
1051 | unsigned long scan; |
1052 | LIST_HEAD(pc_list); |
1053 | struct list_head *src; |
1054 | struct page_cgroup *pc, *tmp; |
1055 | int nid = zone_to_nid(z); |
1056 | int zid = zone_idx(z); |
1057 | struct mem_cgroup_per_zone *mz; |
1058 | int lru = LRU_FILE * file + active; |
1059 | int ret; |
1060 | |
1061 | BUG_ON(!mem_cont); |
1062 | mz = mem_cgroup_zoneinfo(mem_cont, nid, zid); |
1063 | src = &mz->lists[lru]; |
1064 | |
1065 | scan = 0; |
1066 | list_for_each_entry_safe_reverse(pc, tmp, src, lru) { |
1067 | if (scan >= nr_to_scan) |
1068 | break; |
1069 | |
1070 | page = pc->page; |
1071 | if (unlikely(!PageCgroupUsed(pc))) |
1072 | continue; |
1073 | if (unlikely(!PageLRU(page))) |
1074 | continue; |
1075 | |
1076 | scan++; |
1077 | ret = __isolate_lru_page(page, mode, file); |
1078 | switch (ret) { |
1079 | case 0: |
1080 | list_move(&page->lru, dst); |
1081 | mem_cgroup_del_lru(page); |
1082 | nr_taken += hpage_nr_pages(page); |
1083 | break; |
1084 | case -EBUSY: |
1085 | /* we don't affect global LRU but rotate in our LRU */ |
1086 | mem_cgroup_rotate_lru_list(page, page_lru(page)); |
1087 | break; |
1088 | default: |
1089 | break; |
1090 | } |
1091 | } |
1092 | |
1093 | *scanned = scan; |
1094 | |
1095 | trace_mm_vmscan_memcg_isolate(0, nr_to_scan, scan, nr_taken, |
1096 | 0, 0, 0, mode); |
1097 | |
1098 | return nr_taken; |
1099 | } |
1100 | |
1101 | #define mem_cgroup_from_res_counter(counter, member) \ |
1102 | container_of(counter, struct mem_cgroup, member) |
1103 | |
1104 | static bool mem_cgroup_check_under_limit(struct mem_cgroup *mem) |
1105 | { |
1106 | if (do_swap_account) { |
1107 | if (res_counter_check_under_limit(&mem->res) && |
1108 | res_counter_check_under_limit(&mem->memsw)) |
1109 | return true; |
1110 | } else |
1111 | if (res_counter_check_under_limit(&mem->res)) |
1112 | return true; |
1113 | return false; |
1114 | } |
1115 | |
1116 | /** |
1117 | * mem_cgroup_check_margin - check if the memory cgroup allows charging |
1118 | * @mem: memory cgroup to check |
1119 | * @bytes: the number of bytes the caller intends to charge |
1120 | * |
1121 | * Returns a boolean value on whether @mem can be charged @bytes or |
1122 | * whether this would exceed the limit. |
1123 | */ |
1124 | static bool mem_cgroup_check_margin(struct mem_cgroup *mem, unsigned long bytes) |
1125 | { |
1126 | if (!res_counter_check_margin(&mem->res, bytes)) |
1127 | return false; |
1128 | if (do_swap_account && !res_counter_check_margin(&mem->memsw, bytes)) |
1129 | return false; |
1130 | return true; |
1131 | } |
1132 | |
1133 | static unsigned int get_swappiness(struct mem_cgroup *memcg) |
1134 | { |
1135 | struct cgroup *cgrp = memcg->css.cgroup; |
1136 | unsigned int swappiness; |
1137 | |
1138 | /* root ? */ |
1139 | if (cgrp->parent == NULL) |
1140 | return vm_swappiness; |
1141 | |
1142 | spin_lock(&memcg->reclaim_param_lock); |
1143 | swappiness = memcg->swappiness; |
1144 | spin_unlock(&memcg->reclaim_param_lock); |
1145 | |
1146 | return swappiness; |
1147 | } |
1148 | |
1149 | static void mem_cgroup_start_move(struct mem_cgroup *mem) |
1150 | { |
1151 | int cpu; |
1152 | |
1153 | get_online_cpus(); |
1154 | spin_lock(&mem->pcp_counter_lock); |
1155 | for_each_online_cpu(cpu) |
1156 | per_cpu(mem->stat->count[MEM_CGROUP_ON_MOVE], cpu) += 1; |
1157 | mem->nocpu_base.count[MEM_CGROUP_ON_MOVE] += 1; |
1158 | spin_unlock(&mem->pcp_counter_lock); |
1159 | put_online_cpus(); |
1160 | |
1161 | synchronize_rcu(); |
1162 | } |
1163 | |
1164 | static void mem_cgroup_end_move(struct mem_cgroup *mem) |
1165 | { |
1166 | int cpu; |
1167 | |
1168 | if (!mem) |
1169 | return; |
1170 | get_online_cpus(); |
1171 | spin_lock(&mem->pcp_counter_lock); |
1172 | for_each_online_cpu(cpu) |
1173 | per_cpu(mem->stat->count[MEM_CGROUP_ON_MOVE], cpu) -= 1; |
1174 | mem->nocpu_base.count[MEM_CGROUP_ON_MOVE] -= 1; |
1175 | spin_unlock(&mem->pcp_counter_lock); |
1176 | put_online_cpus(); |
1177 | } |
1178 | /* |
1179 | * 2 routines for checking "mem" is under move_account() or not. |
1180 | * |
1181 | * mem_cgroup_stealed() - checking a cgroup is mc.from or not. This is used |
1182 | * for avoiding race in accounting. If true, |
1183 | * pc->mem_cgroup may be overwritten. |
1184 | * |
1185 | * mem_cgroup_under_move() - checking a cgroup is mc.from or mc.to or |
1186 | * under hierarchy of moving cgroups. This is for |
1187 | * waiting at hith-memory prressure caused by "move". |
1188 | */ |
1189 | |
1190 | static bool mem_cgroup_stealed(struct mem_cgroup *mem) |
1191 | { |
1192 | VM_BUG_ON(!rcu_read_lock_held()); |
1193 | return this_cpu_read(mem->stat->count[MEM_CGROUP_ON_MOVE]) > 0; |
1194 | } |
1195 | |
1196 | static bool mem_cgroup_under_move(struct mem_cgroup *mem) |
1197 | { |
1198 | struct mem_cgroup *from; |
1199 | struct mem_cgroup *to; |
1200 | bool ret = false; |
1201 | /* |
1202 | * Unlike task_move routines, we access mc.to, mc.from not under |
1203 | * mutual exclusion by cgroup_mutex. Here, we take spinlock instead. |
1204 | */ |
1205 | spin_lock(&mc.lock); |
1206 | from = mc.from; |
1207 | to = mc.to; |
1208 | if (!from) |
1209 | goto unlock; |
1210 | if (from == mem || to == mem |
1211 | || (mem->use_hierarchy && css_is_ancestor(&from->css, &mem->css)) |
1212 | || (mem->use_hierarchy && css_is_ancestor(&to->css, &mem->css))) |
1213 | ret = true; |
1214 | unlock: |
1215 | spin_unlock(&mc.lock); |
1216 | return ret; |
1217 | } |
1218 | |
1219 | static bool mem_cgroup_wait_acct_move(struct mem_cgroup *mem) |
1220 | { |
1221 | if (mc.moving_task && current != mc.moving_task) { |
1222 | if (mem_cgroup_under_move(mem)) { |
1223 | DEFINE_WAIT(wait); |
1224 | prepare_to_wait(&mc.waitq, &wait, TASK_INTERRUPTIBLE); |
1225 | /* moving charge context might have finished. */ |
1226 | if (mc.moving_task) |
1227 | schedule(); |
1228 | finish_wait(&mc.waitq, &wait); |
1229 | return true; |
1230 | } |
1231 | } |
1232 | return false; |
1233 | } |
1234 | |
1235 | /** |
1236 | * mem_cgroup_print_oom_info: Called from OOM with tasklist_lock held in read mode. |
1237 | * @memcg: The memory cgroup that went over limit |
1238 | * @p: Task that is going to be killed |
1239 | * |
1240 | * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is |
1241 | * enabled |
1242 | */ |
1243 | void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p) |
1244 | { |
1245 | struct cgroup *task_cgrp; |
1246 | struct cgroup *mem_cgrp; |
1247 | /* |
1248 | * Need a buffer in BSS, can't rely on allocations. The code relies |
1249 | * on the assumption that OOM is serialized for memory controller. |
1250 | * If this assumption is broken, revisit this code. |
1251 | */ |
1252 | static char memcg_name[PATH_MAX]; |
1253 | int ret; |
1254 | |
1255 | if (!memcg || !p) |
1256 | return; |
1257 | |
1258 | |
1259 | rcu_read_lock(); |
1260 | |
1261 | mem_cgrp = memcg->css.cgroup; |
1262 | task_cgrp = task_cgroup(p, mem_cgroup_subsys_id); |
1263 | |
1264 | ret = cgroup_path(task_cgrp, memcg_name, PATH_MAX); |
1265 | if (ret < 0) { |
1266 | /* |
1267 | * Unfortunately, we are unable to convert to a useful name |
1268 | * But we'll still print out the usage information |
1269 | */ |
1270 | rcu_read_unlock(); |
1271 | goto done; |
1272 | } |
1273 | rcu_read_unlock(); |
1274 | |
1275 | printk(KERN_INFO "Task in %s killed", memcg_name); |
1276 | |
1277 | rcu_read_lock(); |
1278 | ret = cgroup_path(mem_cgrp, memcg_name, PATH_MAX); |
1279 | if (ret < 0) { |
1280 | rcu_read_unlock(); |
1281 | goto done; |
1282 | } |
1283 | rcu_read_unlock(); |
1284 | |
1285 | /* |
1286 | * Continues from above, so we don't need an KERN_ level |
1287 | */ |
1288 | printk(KERN_CONT " as a result of limit of %s\n", memcg_name); |
1289 | done: |
1290 | |
1291 | printk(KERN_INFO "memory: usage %llukB, limit %llukB, failcnt %llu\n", |
1292 | res_counter_read_u64(&memcg->res, RES_USAGE) >> 10, |
1293 | res_counter_read_u64(&memcg->res, RES_LIMIT) >> 10, |
1294 | res_counter_read_u64(&memcg->res, RES_FAILCNT)); |
1295 | printk(KERN_INFO "memory+swap: usage %llukB, limit %llukB, " |
1296 | "failcnt %llu\n", |
1297 | res_counter_read_u64(&memcg->memsw, RES_USAGE) >> 10, |
1298 | res_counter_read_u64(&memcg->memsw, RES_LIMIT) >> 10, |
1299 | res_counter_read_u64(&memcg->memsw, RES_FAILCNT)); |
1300 | } |
1301 | |
1302 | /* |
1303 | * This function returns the number of memcg under hierarchy tree. Returns |
1304 | * 1(self count) if no children. |
1305 | */ |
1306 | static int mem_cgroup_count_children(struct mem_cgroup *mem) |
1307 | { |
1308 | int num = 0; |
1309 | struct mem_cgroup *iter; |
1310 | |
1311 | for_each_mem_cgroup_tree(iter, mem) |
1312 | num++; |
1313 | return num; |
1314 | } |
1315 | |
1316 | /* |
1317 | * Return the memory (and swap, if configured) limit for a memcg. |
1318 | */ |
1319 | u64 mem_cgroup_get_limit(struct mem_cgroup *memcg) |
1320 | { |
1321 | u64 limit; |
1322 | u64 memsw; |
1323 | |
1324 | limit = res_counter_read_u64(&memcg->res, RES_LIMIT); |
1325 | limit += total_swap_pages << PAGE_SHIFT; |
1326 | |
1327 | memsw = res_counter_read_u64(&memcg->memsw, RES_LIMIT); |
1328 | /* |
1329 | * If memsw is finite and limits the amount of swap space available |
1330 | * to this memcg, return that limit. |
1331 | */ |
1332 | return min(limit, memsw); |
1333 | } |
1334 | |
1335 | /* |
1336 | * Visit the first child (need not be the first child as per the ordering |
1337 | * of the cgroup list, since we track last_scanned_child) of @mem and use |
1338 | * that to reclaim free pages from. |
1339 | */ |
1340 | static struct mem_cgroup * |
1341 | mem_cgroup_select_victim(struct mem_cgroup *root_mem) |
1342 | { |
1343 | struct mem_cgroup *ret = NULL; |
1344 | struct cgroup_subsys_state *css; |
1345 | int nextid, found; |
1346 | |
1347 | if (!root_mem->use_hierarchy) { |
1348 | css_get(&root_mem->css); |
1349 | ret = root_mem; |
1350 | } |
1351 | |
1352 | while (!ret) { |
1353 | rcu_read_lock(); |
1354 | nextid = root_mem->last_scanned_child + 1; |
1355 | css = css_get_next(&mem_cgroup_subsys, nextid, &root_mem->css, |
1356 | &found); |
1357 | if (css && css_tryget(css)) |
1358 | ret = container_of(css, struct mem_cgroup, css); |
1359 | |
1360 | rcu_read_unlock(); |
1361 | /* Updates scanning parameter */ |
1362 | spin_lock(&root_mem->reclaim_param_lock); |
1363 | if (!css) { |
1364 | /* this means start scan from ID:1 */ |
1365 | root_mem->last_scanned_child = 0; |
1366 | } else |
1367 | root_mem->last_scanned_child = found; |
1368 | spin_unlock(&root_mem->reclaim_param_lock); |
1369 | } |
1370 | |
1371 | return ret; |
1372 | } |
1373 | |
1374 | /* |
1375 | * Scan the hierarchy if needed to reclaim memory. We remember the last child |
1376 | * we reclaimed from, so that we don't end up penalizing one child extensively |
1377 | * based on its position in the children list. |
1378 | * |
1379 | * root_mem is the original ancestor that we've been reclaim from. |
1380 | * |
1381 | * We give up and return to the caller when we visit root_mem twice. |
1382 | * (other groups can be removed while we're walking....) |
1383 | * |
1384 | * If shrink==true, for avoiding to free too much, this returns immedieately. |
1385 | */ |
1386 | static int mem_cgroup_hierarchical_reclaim(struct mem_cgroup *root_mem, |
1387 | struct zone *zone, |
1388 | gfp_t gfp_mask, |
1389 | unsigned long reclaim_options) |
1390 | { |
1391 | struct mem_cgroup *victim; |
1392 | int ret, total = 0; |
1393 | int loop = 0; |
1394 | bool noswap = reclaim_options & MEM_CGROUP_RECLAIM_NOSWAP; |
1395 | bool shrink = reclaim_options & MEM_CGROUP_RECLAIM_SHRINK; |
1396 | bool check_soft = reclaim_options & MEM_CGROUP_RECLAIM_SOFT; |
1397 | unsigned long excess = mem_cgroup_get_excess(root_mem); |
1398 | |
1399 | /* If memsw_is_minimum==1, swap-out is of-no-use. */ |
1400 | if (root_mem->memsw_is_minimum) |
1401 | noswap = true; |
1402 | |
1403 | while (1) { |
1404 | victim = mem_cgroup_select_victim(root_mem); |
1405 | if (victim == root_mem) { |
1406 | loop++; |
1407 | if (loop >= 1) |
1408 | drain_all_stock_async(); |
1409 | if (loop >= 2) { |
1410 | /* |
1411 | * If we have not been able to reclaim |
1412 | * anything, it might because there are |
1413 | * no reclaimable pages under this hierarchy |
1414 | */ |
1415 | if (!check_soft || !total) { |
1416 | css_put(&victim->css); |
1417 | break; |
1418 | } |
1419 | /* |
1420 | * We want to do more targetted reclaim. |
1421 | * excess >> 2 is not to excessive so as to |
1422 | * reclaim too much, nor too less that we keep |
1423 | * coming back to reclaim from this cgroup |
1424 | */ |
1425 | if (total >= (excess >> 2) || |
1426 | (loop > MEM_CGROUP_MAX_RECLAIM_LOOPS)) { |
1427 | css_put(&victim->css); |
1428 | break; |
1429 | } |
1430 | } |
1431 | } |
1432 | if (!mem_cgroup_local_usage(victim)) { |
1433 | /* this cgroup's local usage == 0 */ |
1434 | css_put(&victim->css); |
1435 | continue; |
1436 | } |
1437 | /* we use swappiness of local cgroup */ |
1438 | if (check_soft) |
1439 | ret = mem_cgroup_shrink_node_zone(victim, gfp_mask, |
1440 | noswap, get_swappiness(victim), zone); |
1441 | else |
1442 | ret = try_to_free_mem_cgroup_pages(victim, gfp_mask, |
1443 | noswap, get_swappiness(victim)); |
1444 | css_put(&victim->css); |
1445 | /* |
1446 | * At shrinking usage, we can't check we should stop here or |
1447 | * reclaim more. It's depends on callers. last_scanned_child |
1448 | * will work enough for keeping fairness under tree. |
1449 | */ |
1450 | if (shrink) |
1451 | return ret; |
1452 | total += ret; |
1453 | if (check_soft) { |
1454 | if (res_counter_check_under_soft_limit(&root_mem->res)) |
1455 | return total; |
1456 | } else if (mem_cgroup_check_under_limit(root_mem)) |
1457 | return 1 + total; |
1458 | } |
1459 | return total; |
1460 | } |
1461 | |
1462 | /* |
1463 | * Check OOM-Killer is already running under our hierarchy. |
1464 | * If someone is running, return false. |
1465 | */ |
1466 | static bool mem_cgroup_oom_lock(struct mem_cgroup *mem) |
1467 | { |
1468 | int x, lock_count = 0; |
1469 | struct mem_cgroup *iter; |
1470 | |
1471 | for_each_mem_cgroup_tree(iter, mem) { |
1472 | x = atomic_inc_return(&iter->oom_lock); |
1473 | lock_count = max(x, lock_count); |
1474 | } |
1475 | |
1476 | if (lock_count == 1) |
1477 | return true; |
1478 | return false; |
1479 | } |
1480 | |
1481 | static int mem_cgroup_oom_unlock(struct mem_cgroup *mem) |
1482 | { |
1483 | struct mem_cgroup *iter; |
1484 | |
1485 | /* |
1486 | * When a new child is created while the hierarchy is under oom, |
1487 | * mem_cgroup_oom_lock() may not be called. We have to use |
1488 | * atomic_add_unless() here. |
1489 | */ |
1490 | for_each_mem_cgroup_tree(iter, mem) |
1491 | atomic_add_unless(&iter->oom_lock, -1, 0); |
1492 | return 0; |
1493 | } |
1494 | |
1495 | |
1496 | static DEFINE_MUTEX(memcg_oom_mutex); |
1497 | static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq); |
1498 | |
1499 | struct oom_wait_info { |
1500 | struct mem_cgroup *mem; |
1501 | wait_queue_t wait; |
1502 | }; |
1503 | |
1504 | static int memcg_oom_wake_function(wait_queue_t *wait, |
1505 | unsigned mode, int sync, void *arg) |
1506 | { |
1507 | struct mem_cgroup *wake_mem = (struct mem_cgroup *)arg; |
1508 | struct oom_wait_info *oom_wait_info; |
1509 | |
1510 | oom_wait_info = container_of(wait, struct oom_wait_info, wait); |
1511 | |
1512 | if (oom_wait_info->mem == wake_mem) |
1513 | goto wakeup; |
1514 | /* if no hierarchy, no match */ |
1515 | if (!oom_wait_info->mem->use_hierarchy || !wake_mem->use_hierarchy) |
1516 | return 0; |
1517 | /* |
1518 | * Both of oom_wait_info->mem and wake_mem are stable under us. |
1519 | * Then we can use css_is_ancestor without taking care of RCU. |
1520 | */ |
1521 | if (!css_is_ancestor(&oom_wait_info->mem->css, &wake_mem->css) && |
1522 | !css_is_ancestor(&wake_mem->css, &oom_wait_info->mem->css)) |
1523 | return 0; |
1524 | |
1525 | wakeup: |
1526 | return autoremove_wake_function(wait, mode, sync, arg); |
1527 | } |
1528 | |
1529 | static void memcg_wakeup_oom(struct mem_cgroup *mem) |
1530 | { |
1531 | /* for filtering, pass "mem" as argument. */ |
1532 | __wake_up(&memcg_oom_waitq, TASK_NORMAL, 0, mem); |
1533 | } |
1534 | |
1535 | static void memcg_oom_recover(struct mem_cgroup *mem) |
1536 | { |
1537 | if (mem && atomic_read(&mem->oom_lock)) |
1538 | memcg_wakeup_oom(mem); |
1539 | } |
1540 | |
1541 | /* |
1542 | * try to call OOM killer. returns false if we should exit memory-reclaim loop. |
1543 | */ |
1544 | bool mem_cgroup_handle_oom(struct mem_cgroup *mem, gfp_t mask) |
1545 | { |
1546 | struct oom_wait_info owait; |
1547 | bool locked, need_to_kill; |
1548 | |
1549 | owait.mem = mem; |
1550 | owait.wait.flags = 0; |
1551 | owait.wait.func = memcg_oom_wake_function; |
1552 | owait.wait.private = current; |
1553 | INIT_LIST_HEAD(&owait.wait.task_list); |
1554 | need_to_kill = true; |
1555 | /* At first, try to OOM lock hierarchy under mem.*/ |
1556 | mutex_lock(&memcg_oom_mutex); |
1557 | locked = mem_cgroup_oom_lock(mem); |
1558 | /* |
1559 | * Even if signal_pending(), we can't quit charge() loop without |
1560 | * accounting. So, UNINTERRUPTIBLE is appropriate. But SIGKILL |
1561 | * under OOM is always welcomed, use TASK_KILLABLE here. |
1562 | */ |
1563 | prepare_to_wait(&memcg_oom_waitq, &owait.wait, TASK_KILLABLE); |
1564 | if (!locked || mem->oom_kill_disable) |
1565 | need_to_kill = false; |
1566 | if (locked) |
1567 | mem_cgroup_oom_notify(mem); |
1568 | mutex_unlock(&memcg_oom_mutex); |
1569 | |
1570 | if (need_to_kill) { |
1571 | finish_wait(&memcg_oom_waitq, &owait.wait); |
1572 | mem_cgroup_out_of_memory(mem, mask); |
1573 | } else { |
1574 | schedule(); |
1575 | finish_wait(&memcg_oom_waitq, &owait.wait); |
1576 | } |
1577 | mutex_lock(&memcg_oom_mutex); |
1578 | mem_cgroup_oom_unlock(mem); |
1579 | memcg_wakeup_oom(mem); |
1580 | mutex_unlock(&memcg_oom_mutex); |
1581 | |
1582 | if (test_thread_flag(TIF_MEMDIE) || fatal_signal_pending(current)) |
1583 | return false; |
1584 | /* Give chance to dying process */ |
1585 | schedule_timeout(1); |
1586 | return true; |
1587 | } |
1588 | |
1589 | /* |
1590 | * Currently used to update mapped file statistics, but the routine can be |
1591 | * generalized to update other statistics as well. |
1592 | * |
1593 | * Notes: Race condition |
1594 | * |
1595 | * We usually use page_cgroup_lock() for accessing page_cgroup member but |
1596 | * it tends to be costly. But considering some conditions, we doesn't need |
1597 | * to do so _always_. |
1598 | * |
1599 | * Considering "charge", lock_page_cgroup() is not required because all |
1600 | * file-stat operations happen after a page is attached to radix-tree. There |
1601 | * are no race with "charge". |
1602 | * |
1603 | * Considering "uncharge", we know that memcg doesn't clear pc->mem_cgroup |
1604 | * at "uncharge" intentionally. So, we always see valid pc->mem_cgroup even |
1605 | * if there are race with "uncharge". Statistics itself is properly handled |
1606 | * by flags. |
1607 | * |
1608 | * Considering "move", this is an only case we see a race. To make the race |
1609 | * small, we check MEM_CGROUP_ON_MOVE percpu value and detect there are |
1610 | * possibility of race condition. If there is, we take a lock. |
1611 | */ |
1612 | |
1613 | void mem_cgroup_update_page_stat(struct page *page, |
1614 | enum mem_cgroup_page_stat_item idx, int val) |
1615 | { |
1616 | struct mem_cgroup *mem; |
1617 | struct page_cgroup *pc = lookup_page_cgroup(page); |
1618 | bool need_unlock = false; |
1619 | unsigned long uninitialized_var(flags); |
1620 | |
1621 | if (unlikely(!pc)) |
1622 | return; |
1623 | |
1624 | rcu_read_lock(); |
1625 | mem = pc->mem_cgroup; |
1626 | if (unlikely(!mem || !PageCgroupUsed(pc))) |
1627 | goto out; |
1628 | /* pc->mem_cgroup is unstable ? */ |
1629 | if (unlikely(mem_cgroup_stealed(mem)) || PageTransHuge(page)) { |
1630 | /* take a lock against to access pc->mem_cgroup */ |
1631 | move_lock_page_cgroup(pc, &flags); |
1632 | need_unlock = true; |
1633 | mem = pc->mem_cgroup; |
1634 | if (!mem || !PageCgroupUsed(pc)) |
1635 | goto out; |
1636 | } |
1637 | |
1638 | switch (idx) { |
1639 | case MEMCG_NR_FILE_MAPPED: |
1640 | if (val > 0) |
1641 | SetPageCgroupFileMapped(pc); |
1642 | else if (!page_mapped(page)) |
1643 | ClearPageCgroupFileMapped(pc); |
1644 | idx = MEM_CGROUP_STAT_FILE_MAPPED; |
1645 | break; |
1646 | default: |
1647 | BUG(); |
1648 | } |
1649 | |
1650 | this_cpu_add(mem->stat->count[idx], val); |
1651 | |
1652 | out: |
1653 | if (unlikely(need_unlock)) |
1654 | move_unlock_page_cgroup(pc, &flags); |
1655 | rcu_read_unlock(); |
1656 | return; |
1657 | } |
1658 | EXPORT_SYMBOL(mem_cgroup_update_page_stat); |
1659 | |
1660 | /* |
1661 | * size of first charge trial. "32" comes from vmscan.c's magic value. |
1662 | * TODO: maybe necessary to use big numbers in big irons. |
1663 | */ |
1664 | #define CHARGE_SIZE (32 * PAGE_SIZE) |
1665 | struct memcg_stock_pcp { |
1666 | struct mem_cgroup *cached; /* this never be root cgroup */ |
1667 | int charge; |
1668 | struct work_struct work; |
1669 | }; |
1670 | static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock); |
1671 | static atomic_t memcg_drain_count; |
1672 | |
1673 | /* |
1674 | * Try to consume stocked charge on this cpu. If success, PAGE_SIZE is consumed |
1675 | * from local stock and true is returned. If the stock is 0 or charges from a |
1676 | * cgroup which is not current target, returns false. This stock will be |
1677 | * refilled. |
1678 | */ |
1679 | static bool consume_stock(struct mem_cgroup *mem) |
1680 | { |
1681 | struct memcg_stock_pcp *stock; |
1682 | bool ret = true; |
1683 | |
1684 | stock = &get_cpu_var(memcg_stock); |
1685 | if (mem == stock->cached && stock->charge) |
1686 | stock->charge -= PAGE_SIZE; |
1687 | else /* need to call res_counter_charge */ |
1688 | ret = false; |
1689 | put_cpu_var(memcg_stock); |
1690 | return ret; |
1691 | } |
1692 | |
1693 | /* |
1694 | * Returns stocks cached in percpu to res_counter and reset cached information. |
1695 | */ |
1696 | static void drain_stock(struct memcg_stock_pcp *stock) |
1697 | { |
1698 | struct mem_cgroup *old = stock->cached; |
1699 | |
1700 | if (stock->charge) { |
1701 | res_counter_uncharge(&old->res, stock->charge); |
1702 | if (do_swap_account) |
1703 | res_counter_uncharge(&old->memsw, stock->charge); |
1704 | } |
1705 | stock->cached = NULL; |
1706 | stock->charge = 0; |
1707 | } |
1708 | |
1709 | /* |
1710 | * This must be called under preempt disabled or must be called by |
1711 | * a thread which is pinned to local cpu. |
1712 | */ |
1713 | static void drain_local_stock(struct work_struct *dummy) |
1714 | { |
1715 | struct memcg_stock_pcp *stock = &__get_cpu_var(memcg_stock); |
1716 | drain_stock(stock); |
1717 | } |
1718 | |
1719 | /* |
1720 | * Cache charges(val) which is from res_counter, to local per_cpu area. |
1721 | * This will be consumed by consume_stock() function, later. |
1722 | */ |
1723 | static void refill_stock(struct mem_cgroup *mem, int val) |
1724 | { |
1725 | struct memcg_stock_pcp *stock = &get_cpu_var(memcg_stock); |
1726 | |
1727 | if (stock->cached != mem) { /* reset if necessary */ |
1728 | drain_stock(stock); |
1729 | stock->cached = mem; |
1730 | } |
1731 | stock->charge += val; |
1732 | put_cpu_var(memcg_stock); |
1733 | } |
1734 | |
1735 | /* |
1736 | * Tries to drain stocked charges in other cpus. This function is asynchronous |
1737 | * and just put a work per cpu for draining localy on each cpu. Caller can |
1738 | * expects some charges will be back to res_counter later but cannot wait for |
1739 | * it. |
1740 | */ |
1741 | static void drain_all_stock_async(void) |
1742 | { |
1743 | int cpu; |
1744 | /* This function is for scheduling "drain" in asynchronous way. |
1745 | * The result of "drain" is not directly handled by callers. Then, |
1746 | * if someone is calling drain, we don't have to call drain more. |
1747 | * Anyway, WORK_STRUCT_PENDING check in queue_work_on() will catch if |
1748 | * there is a race. We just do loose check here. |
1749 | */ |
1750 | if (atomic_read(&memcg_drain_count)) |
1751 | return; |
1752 | /* Notify other cpus that system-wide "drain" is running */ |
1753 | atomic_inc(&memcg_drain_count); |
1754 | get_online_cpus(); |
1755 | for_each_online_cpu(cpu) { |
1756 | struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu); |
1757 | schedule_work_on(cpu, &stock->work); |
1758 | } |
1759 | put_online_cpus(); |
1760 | atomic_dec(&memcg_drain_count); |
1761 | /* We don't wait for flush_work */ |
1762 | } |
1763 | |
1764 | /* This is a synchronous drain interface. */ |
1765 | static void drain_all_stock_sync(void) |
1766 | { |
1767 | /* called when force_empty is called */ |
1768 | atomic_inc(&memcg_drain_count); |
1769 | schedule_on_each_cpu(drain_local_stock); |
1770 | atomic_dec(&memcg_drain_count); |
1771 | } |
1772 | |
1773 | /* |
1774 | * This function drains percpu counter value from DEAD cpu and |
1775 | * move it to local cpu. Note that this function can be preempted. |
1776 | */ |
1777 | static void mem_cgroup_drain_pcp_counter(struct mem_cgroup *mem, int cpu) |
1778 | { |
1779 | int i; |
1780 | |
1781 | spin_lock(&mem->pcp_counter_lock); |
1782 | for (i = 0; i < MEM_CGROUP_STAT_DATA; i++) { |
1783 | s64 x = per_cpu(mem->stat->count[i], cpu); |
1784 | |
1785 | per_cpu(mem->stat->count[i], cpu) = 0; |
1786 | mem->nocpu_base.count[i] += x; |
1787 | } |
1788 | /* need to clear ON_MOVE value, works as a kind of lock. */ |
1789 | per_cpu(mem->stat->count[MEM_CGROUP_ON_MOVE], cpu) = 0; |
1790 | spin_unlock(&mem->pcp_counter_lock); |
1791 | } |
1792 | |
1793 | static void synchronize_mem_cgroup_on_move(struct mem_cgroup *mem, int cpu) |
1794 | { |
1795 | int idx = MEM_CGROUP_ON_MOVE; |
1796 | |
1797 | spin_lock(&mem->pcp_counter_lock); |
1798 | per_cpu(mem->stat->count[idx], cpu) = mem->nocpu_base.count[idx]; |
1799 | spin_unlock(&mem->pcp_counter_lock); |
1800 | } |
1801 | |
1802 | static int __cpuinit memcg_cpu_hotplug_callback(struct notifier_block *nb, |
1803 | unsigned long action, |
1804 | void *hcpu) |
1805 | { |
1806 | int cpu = (unsigned long)hcpu; |
1807 | struct memcg_stock_pcp *stock; |
1808 | struct mem_cgroup *iter; |
1809 | |
1810 | if ((action == CPU_ONLINE)) { |
1811 | for_each_mem_cgroup_all(iter) |
1812 | synchronize_mem_cgroup_on_move(iter, cpu); |
1813 | return NOTIFY_OK; |
1814 | } |
1815 | |
1816 | if ((action != CPU_DEAD) || action != CPU_DEAD_FROZEN) |
1817 | return NOTIFY_OK; |
1818 | |
1819 | for_each_mem_cgroup_all(iter) |
1820 | mem_cgroup_drain_pcp_counter(iter, cpu); |
1821 | |
1822 | stock = &per_cpu(memcg_stock, cpu); |
1823 | drain_stock(stock); |
1824 | return NOTIFY_OK; |
1825 | } |
1826 | |
1827 | |
1828 | /* See __mem_cgroup_try_charge() for details */ |
1829 | enum { |
1830 | CHARGE_OK, /* success */ |
1831 | CHARGE_RETRY, /* need to retry but retry is not bad */ |
1832 | CHARGE_NOMEM, /* we can't do more. return -ENOMEM */ |
1833 | CHARGE_WOULDBLOCK, /* GFP_WAIT wasn't set and no enough res. */ |
1834 | CHARGE_OOM_DIE, /* the current is killed because of OOM */ |
1835 | }; |
1836 | |
1837 | static int __mem_cgroup_do_charge(struct mem_cgroup *mem, gfp_t gfp_mask, |
1838 | int csize, bool oom_check) |
1839 | { |
1840 | struct mem_cgroup *mem_over_limit; |
1841 | struct res_counter *fail_res; |
1842 | unsigned long flags = 0; |
1843 | int ret; |
1844 | |
1845 | ret = res_counter_charge(&mem->res, csize, &fail_res); |
1846 | |
1847 | if (likely(!ret)) { |
1848 | if (!do_swap_account) |
1849 | return CHARGE_OK; |
1850 | ret = res_counter_charge(&mem->memsw, csize, &fail_res); |
1851 | if (likely(!ret)) |
1852 | return CHARGE_OK; |
1853 | |
1854 | res_counter_uncharge(&mem->res, csize); |
1855 | mem_over_limit = mem_cgroup_from_res_counter(fail_res, memsw); |
1856 | flags |= MEM_CGROUP_RECLAIM_NOSWAP; |
1857 | } else |
1858 | mem_over_limit = mem_cgroup_from_res_counter(fail_res, res); |
1859 | /* |
1860 | * csize can be either a huge page (HPAGE_SIZE), a batch of |
1861 | * regular pages (CHARGE_SIZE), or a single regular page |
1862 | * (PAGE_SIZE). |
1863 | * |
1864 | * Never reclaim on behalf of optional batching, retry with a |
1865 | * single page instead. |
1866 | */ |
1867 | if (csize == CHARGE_SIZE) |
1868 | return CHARGE_RETRY; |
1869 | |
1870 | if (!(gfp_mask & __GFP_WAIT)) |
1871 | return CHARGE_WOULDBLOCK; |
1872 | |
1873 | ret = mem_cgroup_hierarchical_reclaim(mem_over_limit, NULL, |
1874 | gfp_mask, flags); |
1875 | if (mem_cgroup_check_margin(mem_over_limit, csize)) |
1876 | return CHARGE_RETRY; |
1877 | /* |
1878 | * Even though the limit is exceeded at this point, reclaim |
1879 | * may have been able to free some pages. Retry the charge |
1880 | * before killing the task. |
1881 | * |
1882 | * Only for regular pages, though: huge pages are rather |
1883 | * unlikely to succeed so close to the limit, and we fall back |
1884 | * to regular pages anyway in case of failure. |
1885 | */ |
1886 | if (csize == PAGE_SIZE && ret) |
1887 | return CHARGE_RETRY; |
1888 | |
1889 | /* |
1890 | * At task move, charge accounts can be doubly counted. So, it's |
1891 | * better to wait until the end of task_move if something is going on. |
1892 | */ |
1893 | if (mem_cgroup_wait_acct_move(mem_over_limit)) |
1894 | return CHARGE_RETRY; |
1895 | |
1896 | /* If we don't need to call oom-killer at el, return immediately */ |
1897 | if (!oom_check) |
1898 | return CHARGE_NOMEM; |
1899 | /* check OOM */ |
1900 | if (!mem_cgroup_handle_oom(mem_over_limit, gfp_mask)) |
1901 | return CHARGE_OOM_DIE; |
1902 | |
1903 | return CHARGE_RETRY; |
1904 | } |
1905 | |
1906 | /* |
1907 | * Unlike exported interface, "oom" parameter is added. if oom==true, |
1908 | * oom-killer can be invoked. |
1909 | */ |
1910 | static int __mem_cgroup_try_charge(struct mm_struct *mm, |
1911 | gfp_t gfp_mask, |
1912 | struct mem_cgroup **memcg, bool oom, |
1913 | int page_size) |
1914 | { |
1915 | int nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES; |
1916 | struct mem_cgroup *mem = NULL; |
1917 | int ret; |
1918 | int csize = max(CHARGE_SIZE, (unsigned long) page_size); |
1919 | |
1920 | /* |
1921 | * Unlike gloval-vm's OOM-kill, we're not in memory shortage |
1922 | * in system level. So, allow to go ahead dying process in addition to |
1923 | * MEMDIE process. |
1924 | */ |
1925 | if (unlikely(test_thread_flag(TIF_MEMDIE) |
1926 | || fatal_signal_pending(current))) |
1927 | goto bypass; |
1928 | |
1929 | /* |
1930 | * We always charge the cgroup the mm_struct belongs to. |
1931 | * The mm_struct's mem_cgroup changes on task migration if the |
1932 | * thread group leader migrates. It's possible that mm is not |
1933 | * set, if so charge the init_mm (happens for pagecache usage). |
1934 | */ |
1935 | if (!*memcg && !mm) |
1936 | goto bypass; |
1937 | again: |
1938 | if (*memcg) { /* css should be a valid one */ |
1939 | mem = *memcg; |
1940 | VM_BUG_ON(css_is_removed(&mem->css)); |
1941 | if (mem_cgroup_is_root(mem)) |
1942 | goto done; |
1943 | if (page_size == PAGE_SIZE && consume_stock(mem)) |
1944 | goto done; |
1945 | css_get(&mem->css); |
1946 | } else { |
1947 | struct task_struct *p; |
1948 | |
1949 | rcu_read_lock(); |
1950 | p = rcu_dereference(mm->owner); |
1951 | /* |
1952 | * Because we don't have task_lock(), "p" can exit. |
1953 | * In that case, "mem" can point to root or p can be NULL with |
1954 | * race with swapoff. Then, we have small risk of mis-accouning. |
1955 | * But such kind of mis-account by race always happens because |
1956 | * we don't have cgroup_mutex(). It's overkill and we allo that |
1957 | * small race, here. |
1958 | * (*) swapoff at el will charge against mm-struct not against |
1959 | * task-struct. So, mm->owner can be NULL. |
1960 | */ |
1961 | mem = mem_cgroup_from_task(p); |
1962 | if (!mem || mem_cgroup_is_root(mem)) { |
1963 | rcu_read_unlock(); |
1964 | goto done; |
1965 | } |
1966 | if (page_size == PAGE_SIZE && consume_stock(mem)) { |
1967 | /* |
1968 | * It seems dagerous to access memcg without css_get(). |
1969 | * But considering how consume_stok works, it's not |
1970 | * necessary. If consume_stock success, some charges |
1971 | * from this memcg are cached on this cpu. So, we |
1972 | * don't need to call css_get()/css_tryget() before |
1973 | * calling consume_stock(). |
1974 | */ |
1975 | rcu_read_unlock(); |
1976 | goto done; |
1977 | } |
1978 | /* after here, we may be blocked. we need to get refcnt */ |
1979 | if (!css_tryget(&mem->css)) { |
1980 | rcu_read_unlock(); |
1981 | goto again; |
1982 | } |
1983 | rcu_read_unlock(); |
1984 | } |
1985 | |
1986 | do { |
1987 | bool oom_check; |
1988 | |
1989 | /* If killed, bypass charge */ |
1990 | if (fatal_signal_pending(current)) { |
1991 | css_put(&mem->css); |
1992 | goto bypass; |
1993 | } |
1994 | |
1995 | oom_check = false; |
1996 | if (oom && !nr_oom_retries) { |
1997 | oom_check = true; |
1998 | nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES; |
1999 | } |
2000 | |
2001 | ret = __mem_cgroup_do_charge(mem, gfp_mask, csize, oom_check); |
2002 | |
2003 | switch (ret) { |
2004 | case CHARGE_OK: |
2005 | break; |
2006 | case CHARGE_RETRY: /* not in OOM situation but retry */ |
2007 | csize = page_size; |
2008 | css_put(&mem->css); |
2009 | mem = NULL; |
2010 | goto again; |
2011 | case CHARGE_WOULDBLOCK: /* !__GFP_WAIT */ |
2012 | css_put(&mem->css); |
2013 | goto nomem; |
2014 | case CHARGE_NOMEM: /* OOM routine works */ |
2015 | if (!oom) { |
2016 | css_put(&mem->css); |
2017 | goto nomem; |
2018 | } |
2019 | /* If oom, we never return -ENOMEM */ |
2020 | nr_oom_retries--; |
2021 | break; |
2022 | case CHARGE_OOM_DIE: /* Killed by OOM Killer */ |
2023 | css_put(&mem->css); |
2024 | goto bypass; |
2025 | } |
2026 | } while (ret != CHARGE_OK); |
2027 | |
2028 | if (csize > page_size) |
2029 | refill_stock(mem, csize - page_size); |
2030 | css_put(&mem->css); |
2031 | done: |
2032 | *memcg = mem; |
2033 | return 0; |
2034 | nomem: |
2035 | *memcg = NULL; |
2036 | return -ENOMEM; |
2037 | bypass: |
2038 | *memcg = NULL; |
2039 | return 0; |
2040 | } |
2041 | |
2042 | /* |
2043 | * Somemtimes we have to undo a charge we got by try_charge(). |
2044 | * This function is for that and do uncharge, put css's refcnt. |
2045 | * gotten by try_charge(). |
2046 | */ |
2047 | static void __mem_cgroup_cancel_charge(struct mem_cgroup *mem, |
2048 | unsigned long count) |
2049 | { |
2050 | if (!mem_cgroup_is_root(mem)) { |
2051 | res_counter_uncharge(&mem->res, PAGE_SIZE * count); |
2052 | if (do_swap_account) |
2053 | res_counter_uncharge(&mem->memsw, PAGE_SIZE * count); |
2054 | } |
2055 | } |
2056 | |
2057 | static void mem_cgroup_cancel_charge(struct mem_cgroup *mem, |
2058 | int page_size) |
2059 | { |
2060 | __mem_cgroup_cancel_charge(mem, page_size >> PAGE_SHIFT); |
2061 | } |
2062 | |
2063 | /* |
2064 | * A helper function to get mem_cgroup from ID. must be called under |
2065 | * rcu_read_lock(). The caller must check css_is_removed() or some if |
2066 | * it's concern. (dropping refcnt from swap can be called against removed |
2067 | * memcg.) |
2068 | */ |
2069 | static struct mem_cgroup *mem_cgroup_lookup(unsigned short id) |
2070 | { |
2071 | struct cgroup_subsys_state *css; |
2072 | |
2073 | /* ID 0 is unused ID */ |
2074 | if (!id) |
2075 | return NULL; |
2076 | css = css_lookup(&mem_cgroup_subsys, id); |
2077 | if (!css) |
2078 | return NULL; |
2079 | return container_of(css, struct mem_cgroup, css); |
2080 | } |
2081 | |
2082 | struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page) |
2083 | { |
2084 | struct mem_cgroup *mem = NULL; |
2085 | struct page_cgroup *pc; |
2086 | unsigned short id; |
2087 | swp_entry_t ent; |
2088 | |
2089 | VM_BUG_ON(!PageLocked(page)); |
2090 | |
2091 | pc = lookup_page_cgroup(page); |
2092 | lock_page_cgroup(pc); |
2093 | if (PageCgroupUsed(pc)) { |
2094 | mem = pc->mem_cgroup; |
2095 | if (mem && !css_tryget(&mem->css)) |
2096 | mem = NULL; |
2097 | } else if (PageSwapCache(page)) { |
2098 | ent.val = page_private(page); |
2099 | id = lookup_swap_cgroup(ent); |
2100 | rcu_read_lock(); |
2101 | mem = mem_cgroup_lookup(id); |
2102 | if (mem && !css_tryget(&mem->css)) |
2103 | mem = NULL; |
2104 | rcu_read_unlock(); |
2105 | } |
2106 | unlock_page_cgroup(pc); |
2107 | return mem; |
2108 | } |
2109 | |
2110 | static void __mem_cgroup_commit_charge(struct mem_cgroup *mem, |
2111 | struct page_cgroup *pc, |
2112 | enum charge_type ctype, |
2113 | int page_size) |
2114 | { |
2115 | int nr_pages = page_size >> PAGE_SHIFT; |
2116 | |
2117 | /* try_charge() can return NULL to *memcg, taking care of it. */ |
2118 | if (!mem) |
2119 | return; |
2120 | |
2121 | lock_page_cgroup(pc); |
2122 | if (unlikely(PageCgroupUsed(pc))) { |
2123 | unlock_page_cgroup(pc); |
2124 | mem_cgroup_cancel_charge(mem, page_size); |
2125 | return; |
2126 | } |
2127 | /* |
2128 | * we don't need page_cgroup_lock about tail pages, becase they are not |
2129 | * accessed by any other context at this point. |
2130 | */ |
2131 | pc->mem_cgroup = mem; |
2132 | /* |
2133 | * We access a page_cgroup asynchronously without lock_page_cgroup(). |
2134 | * Especially when a page_cgroup is taken from a page, pc->mem_cgroup |
2135 | * is accessed after testing USED bit. To make pc->mem_cgroup visible |
2136 | * before USED bit, we need memory barrier here. |
2137 | * See mem_cgroup_add_lru_list(), etc. |
2138 | */ |
2139 | smp_wmb(); |
2140 | switch (ctype) { |
2141 | case MEM_CGROUP_CHARGE_TYPE_CACHE: |
2142 | case MEM_CGROUP_CHARGE_TYPE_SHMEM: |
2143 | SetPageCgroupCache(pc); |
2144 | SetPageCgroupUsed(pc); |
2145 | break; |
2146 | case MEM_CGROUP_CHARGE_TYPE_MAPPED: |
2147 | ClearPageCgroupCache(pc); |
2148 | SetPageCgroupUsed(pc); |
2149 | break; |
2150 | default: |
2151 | break; |
2152 | } |
2153 | |
2154 | mem_cgroup_charge_statistics(mem, PageCgroupCache(pc), nr_pages); |
2155 | unlock_page_cgroup(pc); |
2156 | /* |
2157 | * "charge_statistics" updated event counter. Then, check it. |
2158 | * Insert ancestor (and ancestor's ancestors), to softlimit RB-tree. |
2159 | * if they exceeds softlimit. |
2160 | */ |
2161 | memcg_check_events(mem, pc->page); |
2162 | } |
2163 | |
2164 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE |
2165 | |
2166 | #define PCGF_NOCOPY_AT_SPLIT ((1 << PCG_LOCK) | (1 << PCG_MOVE_LOCK) |\ |
2167 | (1 << PCG_ACCT_LRU) | (1 << PCG_MIGRATION)) |
2168 | /* |
2169 | * Because tail pages are not marked as "used", set it. We're under |
2170 | * zone->lru_lock, 'splitting on pmd' and compund_lock. |
2171 | */ |
2172 | void mem_cgroup_split_huge_fixup(struct page *head, struct page *tail) |
2173 | { |
2174 | struct page_cgroup *head_pc = lookup_page_cgroup(head); |
2175 | struct page_cgroup *tail_pc = lookup_page_cgroup(tail); |
2176 | unsigned long flags; |
2177 | |
2178 | if (mem_cgroup_disabled()) |
2179 | return; |
2180 | /* |
2181 | * We have no races with charge/uncharge but will have races with |
2182 | * page state accounting. |
2183 | */ |
2184 | move_lock_page_cgroup(head_pc, &flags); |
2185 | |
2186 | tail_pc->mem_cgroup = head_pc->mem_cgroup; |
2187 | smp_wmb(); /* see __commit_charge() */ |
2188 | if (PageCgroupAcctLRU(head_pc)) { |
2189 | enum lru_list lru; |
2190 | struct mem_cgroup_per_zone *mz; |
2191 | |
2192 | /* |
2193 | * LRU flags cannot be copied because we need to add tail |
2194 | *.page to LRU by generic call and our hook will be called. |
2195 | * We hold lru_lock, then, reduce counter directly. |
2196 | */ |
2197 | lru = page_lru(head); |
2198 | mz = page_cgroup_zoneinfo(head_pc); |
2199 | MEM_CGROUP_ZSTAT(mz, lru) -= 1; |
2200 | } |
2201 | tail_pc->flags = head_pc->flags & ~PCGF_NOCOPY_AT_SPLIT; |
2202 | move_unlock_page_cgroup(head_pc, &flags); |
2203 | } |
2204 | #endif |
2205 | |
2206 | /** |
2207 | * __mem_cgroup_move_account - move account of the page |
2208 | * @pc: page_cgroup of the page. |
2209 | * @from: mem_cgroup which the page is moved from. |
2210 | * @to: mem_cgroup which the page is moved to. @from != @to. |
2211 | * @uncharge: whether we should call uncharge and css_put against @from. |
2212 | * |
2213 | * The caller must confirm following. |
2214 | * - page is not on LRU (isolate_page() is useful.) |
2215 | * - the pc is locked, used, and ->mem_cgroup points to @from. |
2216 | * |
2217 | * This function doesn't do "charge" nor css_get to new cgroup. It should be |
2218 | * done by a caller(__mem_cgroup_try_charge would be usefull). If @uncharge is |
2219 | * true, this function does "uncharge" from old cgroup, but it doesn't if |
2220 | * @uncharge is false, so a caller should do "uncharge". |
2221 | */ |
2222 | |
2223 | static void __mem_cgroup_move_account(struct page_cgroup *pc, |
2224 | struct mem_cgroup *from, struct mem_cgroup *to, bool uncharge, |
2225 | int charge_size) |
2226 | { |
2227 | int nr_pages = charge_size >> PAGE_SHIFT; |
2228 | |
2229 | VM_BUG_ON(from == to); |
2230 | VM_BUG_ON(PageLRU(pc->page)); |
2231 | VM_BUG_ON(!page_is_cgroup_locked(pc)); |
2232 | VM_BUG_ON(!PageCgroupUsed(pc)); |
2233 | VM_BUG_ON(pc->mem_cgroup != from); |
2234 | |
2235 | if (PageCgroupFileMapped(pc)) { |
2236 | /* Update mapped_file data for mem_cgroup */ |
2237 | preempt_disable(); |
2238 | __this_cpu_dec(from->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]); |
2239 | __this_cpu_inc(to->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]); |
2240 | preempt_enable(); |
2241 | } |
2242 | mem_cgroup_charge_statistics(from, PageCgroupCache(pc), -nr_pages); |
2243 | if (uncharge) |
2244 | /* This is not "cancel", but cancel_charge does all we need. */ |
2245 | mem_cgroup_cancel_charge(from, charge_size); |
2246 | |
2247 | /* caller should have done css_get */ |
2248 | pc->mem_cgroup = to; |
2249 | mem_cgroup_charge_statistics(to, PageCgroupCache(pc), nr_pages); |
2250 | /* |
2251 | * We charges against "to" which may not have any tasks. Then, "to" |
2252 | * can be under rmdir(). But in current implementation, caller of |
2253 | * this function is just force_empty() and move charge, so it's |
2254 | * garanteed that "to" is never removed. So, we don't check rmdir |
2255 | * status here. |
2256 | */ |
2257 | } |
2258 | |
2259 | /* |
2260 | * check whether the @pc is valid for moving account and call |
2261 | * __mem_cgroup_move_account() |
2262 | */ |
2263 | static int mem_cgroup_move_account(struct page_cgroup *pc, |
2264 | struct mem_cgroup *from, struct mem_cgroup *to, |
2265 | bool uncharge, int charge_size) |
2266 | { |
2267 | int ret = -EINVAL; |
2268 | unsigned long flags; |
2269 | /* |
2270 | * The page is isolated from LRU. So, collapse function |
2271 | * will not handle this page. But page splitting can happen. |
2272 | * Do this check under compound_page_lock(). The caller should |
2273 | * hold it. |
2274 | */ |
2275 | if ((charge_size > PAGE_SIZE) && !PageTransHuge(pc->page)) |
2276 | return -EBUSY; |
2277 | |
2278 | lock_page_cgroup(pc); |
2279 | if (PageCgroupUsed(pc) && pc->mem_cgroup == from) { |
2280 | move_lock_page_cgroup(pc, &flags); |
2281 | __mem_cgroup_move_account(pc, from, to, uncharge, charge_size); |
2282 | move_unlock_page_cgroup(pc, &flags); |
2283 | ret = 0; |
2284 | } |
2285 | unlock_page_cgroup(pc); |
2286 | /* |
2287 | * check events |
2288 | */ |
2289 | memcg_check_events(to, pc->page); |
2290 | memcg_check_events(from, pc->page); |
2291 | return ret; |
2292 | } |
2293 | |
2294 | /* |
2295 | * move charges to its parent. |
2296 | */ |
2297 | |
2298 | static int mem_cgroup_move_parent(struct page_cgroup *pc, |
2299 | struct mem_cgroup *child, |
2300 | gfp_t gfp_mask) |
2301 | { |
2302 | struct page *page = pc->page; |
2303 | struct cgroup *cg = child->css.cgroup; |
2304 | struct cgroup *pcg = cg->parent; |
2305 | struct mem_cgroup *parent; |
2306 | int page_size = PAGE_SIZE; |
2307 | unsigned long flags; |
2308 | int ret; |
2309 | |
2310 | /* Is ROOT ? */ |
2311 | if (!pcg) |
2312 | return -EINVAL; |
2313 | |
2314 | ret = -EBUSY; |
2315 | if (!get_page_unless_zero(page)) |
2316 | goto out; |
2317 | if (isolate_lru_page(page)) |
2318 | goto put; |
2319 | |
2320 | if (PageTransHuge(page)) |
2321 | page_size = HPAGE_SIZE; |
2322 | |
2323 | parent = mem_cgroup_from_cont(pcg); |
2324 | ret = __mem_cgroup_try_charge(NULL, gfp_mask, |
2325 | &parent, false, page_size); |
2326 | if (ret || !parent) |
2327 | goto put_back; |
2328 | |
2329 | if (page_size > PAGE_SIZE) |
2330 | flags = compound_lock_irqsave(page); |
2331 | |
2332 | ret = mem_cgroup_move_account(pc, child, parent, true, page_size); |
2333 | if (ret) |
2334 | mem_cgroup_cancel_charge(parent, page_size); |
2335 | |
2336 | if (page_size > PAGE_SIZE) |
2337 | compound_unlock_irqrestore(page, flags); |
2338 | put_back: |
2339 | putback_lru_page(page); |
2340 | put: |
2341 | put_page(page); |
2342 | out: |
2343 | return ret; |
2344 | } |
2345 | |
2346 | /* |
2347 | * Charge the memory controller for page usage. |
2348 | * Return |
2349 | * 0 if the charge was successful |
2350 | * < 0 if the cgroup is over its limit |
2351 | */ |
2352 | static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm, |
2353 | gfp_t gfp_mask, enum charge_type ctype) |
2354 | { |
2355 | struct mem_cgroup *mem = NULL; |
2356 | int page_size = PAGE_SIZE; |
2357 | struct page_cgroup *pc; |
2358 | bool oom = true; |
2359 | int ret; |
2360 | |
2361 | if (PageTransHuge(page)) { |
2362 | page_size <<= compound_order(page); |
2363 | VM_BUG_ON(!PageTransHuge(page)); |
2364 | /* |
2365 | * Never OOM-kill a process for a huge page. The |
2366 | * fault handler will fall back to regular pages. |
2367 | */ |
2368 | oom = false; |
2369 | } |
2370 | |
2371 | pc = lookup_page_cgroup(page); |
2372 | /* can happen at boot */ |
2373 | if (unlikely(!pc)) |
2374 | return 0; |
2375 | prefetchw(pc); |
2376 | |
2377 | ret = __mem_cgroup_try_charge(mm, gfp_mask, &mem, oom, page_size); |
2378 | if (ret || !mem) |
2379 | return ret; |
2380 | |
2381 | __mem_cgroup_commit_charge(mem, pc, ctype, page_size); |
2382 | return 0; |
2383 | } |
2384 | |
2385 | int mem_cgroup_newpage_charge(struct page *page, |
2386 | struct mm_struct *mm, gfp_t gfp_mask) |
2387 | { |
2388 | if (mem_cgroup_disabled()) |
2389 | return 0; |
2390 | /* |
2391 | * If already mapped, we don't have to account. |
2392 | * If page cache, page->mapping has address_space. |
2393 | * But page->mapping may have out-of-use anon_vma pointer, |
2394 | * detecit it by PageAnon() check. newly-mapped-anon's page->mapping |
2395 | * is NULL. |
2396 | */ |
2397 | if (page_mapped(page) || (page->mapping && !PageAnon(page))) |
2398 | return 0; |
2399 | if (unlikely(!mm)) |
2400 | mm = &init_mm; |
2401 | return mem_cgroup_charge_common(page, mm, gfp_mask, |
2402 | MEM_CGROUP_CHARGE_TYPE_MAPPED); |
2403 | } |
2404 | |
2405 | static void |
2406 | __mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr, |
2407 | enum charge_type ctype); |
2408 | |
2409 | int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm, |
2410 | gfp_t gfp_mask) |
2411 | { |
2412 | int ret; |
2413 | |
2414 | if (mem_cgroup_disabled()) |
2415 | return 0; |
2416 | if (PageCompound(page)) |
2417 | return 0; |
2418 | /* |
2419 | * Corner case handling. This is called from add_to_page_cache() |
2420 | * in usual. But some FS (shmem) precharges this page before calling it |
2421 | * and call add_to_page_cache() with GFP_NOWAIT. |
2422 | * |
2423 | * For GFP_NOWAIT case, the page may be pre-charged before calling |
2424 | * add_to_page_cache(). (See shmem.c) check it here and avoid to call |
2425 | * charge twice. (It works but has to pay a bit larger cost.) |
2426 | * And when the page is SwapCache, it should take swap information |
2427 | * into account. This is under lock_page() now. |
2428 | */ |
2429 | if (!(gfp_mask & __GFP_WAIT)) { |
2430 | struct page_cgroup *pc; |
2431 | |
2432 | pc = lookup_page_cgroup(page); |
2433 | if (!pc) |
2434 | return 0; |
2435 | lock_page_cgroup(pc); |
2436 | if (PageCgroupUsed(pc)) { |
2437 | unlock_page_cgroup(pc); |
2438 | return 0; |
2439 | } |
2440 | unlock_page_cgroup(pc); |
2441 | } |
2442 | |
2443 | if (unlikely(!mm)) |
2444 | mm = &init_mm; |
2445 | |
2446 | if (page_is_file_cache(page)) |
2447 | return mem_cgroup_charge_common(page, mm, gfp_mask, |
2448 | MEM_CGROUP_CHARGE_TYPE_CACHE); |
2449 | |
2450 | /* shmem */ |
2451 | if (PageSwapCache(page)) { |
2452 | struct mem_cgroup *mem = NULL; |
2453 | |
2454 | ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &mem); |
2455 | if (!ret) |
2456 | __mem_cgroup_commit_charge_swapin(page, mem, |
2457 | MEM_CGROUP_CHARGE_TYPE_SHMEM); |
2458 | } else |
2459 | ret = mem_cgroup_charge_common(page, mm, gfp_mask, |
2460 | MEM_CGROUP_CHARGE_TYPE_SHMEM); |
2461 | |
2462 | return ret; |
2463 | } |
2464 | |
2465 | /* |
2466 | * While swap-in, try_charge -> commit or cancel, the page is locked. |
2467 | * And when try_charge() successfully returns, one refcnt to memcg without |
2468 | * struct page_cgroup is acquired. This refcnt will be consumed by |
2469 | * "commit()" or removed by "cancel()" |
2470 | */ |
2471 | int mem_cgroup_try_charge_swapin(struct mm_struct *mm, |
2472 | struct page *page, |
2473 | gfp_t mask, struct mem_cgroup **ptr) |
2474 | { |
2475 | struct mem_cgroup *mem; |
2476 | int ret; |
2477 | |
2478 | if (mem_cgroup_disabled()) |
2479 | return 0; |
2480 | |
2481 | if (!do_swap_account) |
2482 | goto charge_cur_mm; |
2483 | /* |
2484 | * A racing thread's fault, or swapoff, may have already updated |
2485 | * the pte, and even removed page from swap cache: in those cases |
2486 | * do_swap_page()'s pte_same() test will fail; but there's also a |
2487 | * KSM case which does need to charge the page. |
2488 | */ |
2489 | if (!PageSwapCache(page)) |
2490 | goto charge_cur_mm; |
2491 | mem = try_get_mem_cgroup_from_page(page); |
2492 | if (!mem) |
2493 | goto charge_cur_mm; |
2494 | *ptr = mem; |
2495 | ret = __mem_cgroup_try_charge(NULL, mask, ptr, true, PAGE_SIZE); |
2496 | css_put(&mem->css); |
2497 | return ret; |
2498 | charge_cur_mm: |
2499 | if (unlikely(!mm)) |
2500 | mm = &init_mm; |
2501 | return __mem_cgroup_try_charge(mm, mask, ptr, true, PAGE_SIZE); |
2502 | } |
2503 | |
2504 | static void |
2505 | __mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr, |
2506 | enum charge_type ctype) |
2507 | { |
2508 | struct page_cgroup *pc; |
2509 | |
2510 | if (mem_cgroup_disabled()) |
2511 | return; |
2512 | if (!ptr) |
2513 | return; |
2514 | cgroup_exclude_rmdir(&ptr->css); |
2515 | pc = lookup_page_cgroup(page); |
2516 | mem_cgroup_lru_del_before_commit_swapcache(page); |
2517 | __mem_cgroup_commit_charge(ptr, pc, ctype, PAGE_SIZE); |
2518 | mem_cgroup_lru_add_after_commit_swapcache(page); |
2519 | /* |
2520 | * Now swap is on-memory. This means this page may be |
2521 | * counted both as mem and swap....double count. |
2522 | * Fix it by uncharging from memsw. Basically, this SwapCache is stable |
2523 | * under lock_page(). But in do_swap_page()::memory.c, reuse_swap_page() |
2524 | * may call delete_from_swap_cache() before reach here. |
2525 | */ |
2526 | if (do_swap_account && PageSwapCache(page)) { |
2527 | swp_entry_t ent = {.val = page_private(page)}; |
2528 | unsigned short id; |
2529 | struct mem_cgroup *memcg; |
2530 | |
2531 | id = swap_cgroup_record(ent, 0); |
2532 | rcu_read_lock(); |
2533 | memcg = mem_cgroup_lookup(id); |
2534 | if (memcg) { |
2535 | /* |
2536 | * This recorded memcg can be obsolete one. So, avoid |
2537 | * calling css_tryget |
2538 | */ |
2539 | if (!mem_cgroup_is_root(memcg)) |
2540 | res_counter_uncharge(&memcg->memsw, PAGE_SIZE); |
2541 | mem_cgroup_swap_statistics(memcg, false); |
2542 | mem_cgroup_put(memcg); |
2543 | } |
2544 | rcu_read_unlock(); |
2545 | } |
2546 | /* |
2547 | * At swapin, we may charge account against cgroup which has no tasks. |
2548 | * So, rmdir()->pre_destroy() can be called while we do this charge. |
2549 | * In that case, we need to call pre_destroy() again. check it here. |
2550 | */ |
2551 | cgroup_release_and_wakeup_rmdir(&ptr->css); |
2552 | } |
2553 | |
2554 | void mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr) |
2555 | { |
2556 | __mem_cgroup_commit_charge_swapin(page, ptr, |
2557 | MEM_CGROUP_CHARGE_TYPE_MAPPED); |
2558 | } |
2559 | |
2560 | void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *mem) |
2561 | { |
2562 | if (mem_cgroup_disabled()) |
2563 | return; |
2564 | if (!mem) |
2565 | return; |
2566 | mem_cgroup_cancel_charge(mem, PAGE_SIZE); |
2567 | } |
2568 | |
2569 | static void |
2570 | __do_uncharge(struct mem_cgroup *mem, const enum charge_type ctype, |
2571 | int page_size) |
2572 | { |
2573 | struct memcg_batch_info *batch = NULL; |
2574 | bool uncharge_memsw = true; |
2575 | /* If swapout, usage of swap doesn't decrease */ |
2576 | if (!do_swap_account || ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT) |
2577 | uncharge_memsw = false; |
2578 | |
2579 | batch = ¤t->memcg_batch; |
2580 | /* |
2581 | * In usual, we do css_get() when we remember memcg pointer. |
2582 | * But in this case, we keep res->usage until end of a series of |
2583 | * uncharges. Then, it's ok to ignore memcg's refcnt. |
2584 | */ |
2585 | if (!batch->memcg) |
2586 | batch->memcg = mem; |
2587 | /* |
2588 | * do_batch > 0 when unmapping pages or inode invalidate/truncate. |
2589 | * In those cases, all pages freed continously can be expected to be in |
2590 | * the same cgroup and we have chance to coalesce uncharges. |
2591 | * But we do uncharge one by one if this is killed by OOM(TIF_MEMDIE) |
2592 | * because we want to do uncharge as soon as possible. |
2593 | */ |
2594 | |
2595 | if (!batch->do_batch || test_thread_flag(TIF_MEMDIE)) |
2596 | goto direct_uncharge; |
2597 | |
2598 | if (page_size != PAGE_SIZE) |
2599 | goto direct_uncharge; |
2600 | |
2601 | /* |
2602 | * In typical case, batch->memcg == mem. This means we can |
2603 | * merge a series of uncharges to an uncharge of res_counter. |
2604 | * If not, we uncharge res_counter ony by one. |
2605 | */ |
2606 | if (batch->memcg != mem) |
2607 | goto direct_uncharge; |
2608 | /* remember freed charge and uncharge it later */ |
2609 | batch->bytes += PAGE_SIZE; |
2610 | if (uncharge_memsw) |
2611 | batch->memsw_bytes += PAGE_SIZE; |
2612 | return; |
2613 | direct_uncharge: |
2614 | res_counter_uncharge(&mem->res, page_size); |
2615 | if (uncharge_memsw) |
2616 | res_counter_uncharge(&mem->memsw, page_size); |
2617 | if (unlikely(batch->memcg != mem)) |
2618 | memcg_oom_recover(mem); |
2619 | return; |
2620 | } |
2621 | |
2622 | /* |
2623 | * uncharge if !page_mapped(page) |
2624 | */ |
2625 | static struct mem_cgroup * |
2626 | __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype) |
2627 | { |
2628 | int count; |
2629 | struct page_cgroup *pc; |
2630 | struct mem_cgroup *mem = NULL; |
2631 | int page_size = PAGE_SIZE; |
2632 | |
2633 | if (mem_cgroup_disabled()) |
2634 | return NULL; |
2635 | |
2636 | if (PageSwapCache(page)) |
2637 | return NULL; |
2638 | |
2639 | if (PageTransHuge(page)) { |
2640 | page_size <<= compound_order(page); |
2641 | VM_BUG_ON(!PageTransHuge(page)); |
2642 | } |
2643 | |
2644 | count = page_size >> PAGE_SHIFT; |
2645 | /* |
2646 | * Check if our page_cgroup is valid |
2647 | */ |
2648 | pc = lookup_page_cgroup(page); |
2649 | if (unlikely(!pc || !PageCgroupUsed(pc))) |
2650 | return NULL; |
2651 | |
2652 | lock_page_cgroup(pc); |
2653 | |
2654 | mem = pc->mem_cgroup; |
2655 | |
2656 | if (!PageCgroupUsed(pc)) |
2657 | goto unlock_out; |
2658 | |
2659 | switch (ctype) { |
2660 | case MEM_CGROUP_CHARGE_TYPE_MAPPED: |
2661 | case MEM_CGROUP_CHARGE_TYPE_DROP: |
2662 | /* See mem_cgroup_prepare_migration() */ |
2663 | if (page_mapped(page) || PageCgroupMigration(pc)) |
2664 | goto unlock_out; |
2665 | break; |
2666 | case MEM_CGROUP_CHARGE_TYPE_SWAPOUT: |
2667 | if (!PageAnon(page)) { /* Shared memory */ |
2668 | if (page->mapping && !page_is_file_cache(page)) |
2669 | goto unlock_out; |
2670 | } else if (page_mapped(page)) /* Anon */ |
2671 | goto unlock_out; |
2672 | break; |
2673 | default: |
2674 | break; |
2675 | } |
2676 | |
2677 | mem_cgroup_charge_statistics(mem, PageCgroupCache(pc), -count); |
2678 | |
2679 | ClearPageCgroupUsed(pc); |
2680 | /* |
2681 | * pc->mem_cgroup is not cleared here. It will be accessed when it's |
2682 | * freed from LRU. This is safe because uncharged page is expected not |
2683 | * to be reused (freed soon). Exception is SwapCache, it's handled by |
2684 | * special functions. |
2685 | */ |
2686 | |
2687 | unlock_page_cgroup(pc); |
2688 | /* |
2689 | * even after unlock, we have mem->res.usage here and this memcg |
2690 | * will never be freed. |
2691 | */ |
2692 | memcg_check_events(mem, page); |
2693 | if (do_swap_account && ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT) { |
2694 | mem_cgroup_swap_statistics(mem, true); |
2695 | mem_cgroup_get(mem); |
2696 | } |
2697 | if (!mem_cgroup_is_root(mem)) |
2698 | __do_uncharge(mem, ctype, page_size); |
2699 | |
2700 | return mem; |
2701 | |
2702 | unlock_out: |
2703 | unlock_page_cgroup(pc); |
2704 | return NULL; |
2705 | } |
2706 | |
2707 | void mem_cgroup_uncharge_page(struct page *page) |
2708 | { |
2709 | /* early check. */ |
2710 | if (page_mapped(page)) |
2711 | return; |
2712 | if (page->mapping && !PageAnon(page)) |
2713 | return; |
2714 | __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_MAPPED); |
2715 | } |
2716 | |
2717 | void mem_cgroup_uncharge_cache_page(struct page *page) |
2718 | { |
2719 | VM_BUG_ON(page_mapped(page)); |
2720 | VM_BUG_ON(page->mapping); |
2721 | __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE); |
2722 | } |
2723 | |
2724 | /* |
2725 | * Batch_start/batch_end is called in unmap_page_range/invlidate/trucate. |
2726 | * In that cases, pages are freed continuously and we can expect pages |
2727 | * are in the same memcg. All these calls itself limits the number of |
2728 | * pages freed at once, then uncharge_start/end() is called properly. |
2729 | * This may be called prural(2) times in a context, |
2730 | */ |
2731 | |
2732 | void mem_cgroup_uncharge_start(void) |
2733 | { |
2734 | current->memcg_batch.do_batch++; |
2735 | /* We can do nest. */ |
2736 | if (current->memcg_batch.do_batch == 1) { |
2737 | current->memcg_batch.memcg = NULL; |
2738 | current->memcg_batch.bytes = 0; |
2739 | current->memcg_batch.memsw_bytes = 0; |
2740 | } |
2741 | } |
2742 | |
2743 | void mem_cgroup_uncharge_end(void) |
2744 | { |
2745 | struct memcg_batch_info *batch = ¤t->memcg_batch; |
2746 | |
2747 | if (!batch->do_batch) |
2748 | return; |
2749 | |
2750 | batch->do_batch--; |
2751 | if (batch->do_batch) /* If stacked, do nothing. */ |
2752 | return; |
2753 | |
2754 | if (!batch->memcg) |
2755 | return; |
2756 | /* |
2757 | * This "batch->memcg" is valid without any css_get/put etc... |
2758 | * bacause we hide charges behind us. |
2759 | */ |
2760 | if (batch->bytes) |
2761 | res_counter_uncharge(&batch->memcg->res, batch->bytes); |
2762 | if (batch->memsw_bytes) |
2763 | res_counter_uncharge(&batch->memcg->memsw, batch->memsw_bytes); |
2764 | memcg_oom_recover(batch->memcg); |
2765 | /* forget this pointer (for sanity check) */ |
2766 | batch->memcg = NULL; |
2767 | } |
2768 | |
2769 | #ifdef CONFIG_SWAP |
2770 | /* |
2771 | * called after __delete_from_swap_cache() and drop "page" account. |
2772 | * memcg information is recorded to swap_cgroup of "ent" |
2773 | */ |
2774 | void |
2775 | mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout) |
2776 | { |
2777 | struct mem_cgroup *memcg; |
2778 | int ctype = MEM_CGROUP_CHARGE_TYPE_SWAPOUT; |
2779 | |
2780 | if (!swapout) /* this was a swap cache but the swap is unused ! */ |
2781 | ctype = MEM_CGROUP_CHARGE_TYPE_DROP; |
2782 | |
2783 | memcg = __mem_cgroup_uncharge_common(page, ctype); |
2784 | |
2785 | /* |
2786 | * record memcg information, if swapout && memcg != NULL, |
2787 | * mem_cgroup_get() was called in uncharge(). |
2788 | */ |
2789 | if (do_swap_account && swapout && memcg) |
2790 | swap_cgroup_record(ent, css_id(&memcg->css)); |
2791 | } |
2792 | #endif |
2793 | |
2794 | #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP |
2795 | /* |
2796 | * called from swap_entry_free(). remove record in swap_cgroup and |
2797 | * uncharge "memsw" account. |
2798 | */ |
2799 | void mem_cgroup_uncharge_swap(swp_entry_t ent) |
2800 | { |
2801 | struct mem_cgroup *memcg; |
2802 | unsigned short id; |
2803 | |
2804 | if (!do_swap_account) |
2805 | return; |
2806 | |
2807 | id = swap_cgroup_record(ent, 0); |
2808 | rcu_read_lock(); |
2809 | memcg = mem_cgroup_lookup(id); |
2810 | if (memcg) { |
2811 | /* |
2812 | * We uncharge this because swap is freed. |
2813 | * This memcg can be obsolete one. We avoid calling css_tryget |
2814 | */ |
2815 | if (!mem_cgroup_is_root(memcg)) |
2816 | res_counter_uncharge(&memcg->memsw, PAGE_SIZE); |
2817 | mem_cgroup_swap_statistics(memcg, false); |
2818 | mem_cgroup_put(memcg); |
2819 | } |
2820 | rcu_read_unlock(); |
2821 | } |
2822 | |
2823 | /** |
2824 | * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record. |
2825 | * @entry: swap entry to be moved |
2826 | * @from: mem_cgroup which the entry is moved from |
2827 | * @to: mem_cgroup which the entry is moved to |
2828 | * @need_fixup: whether we should fixup res_counters and refcounts. |
2829 | * |
2830 | * It succeeds only when the swap_cgroup's record for this entry is the same |
2831 | * as the mem_cgroup's id of @from. |
2832 | * |
2833 | * Returns 0 on success, -EINVAL on failure. |
2834 | * |
2835 | * The caller must have charged to @to, IOW, called res_counter_charge() about |
2836 | * both res and memsw, and called css_get(). |
2837 | */ |
2838 | static int mem_cgroup_move_swap_account(swp_entry_t entry, |
2839 | struct mem_cgroup *from, struct mem_cgroup *to, bool need_fixup) |
2840 | { |
2841 | unsigned short old_id, new_id; |
2842 | |
2843 | old_id = css_id(&from->css); |
2844 | new_id = css_id(&to->css); |
2845 | |
2846 | if (swap_cgroup_cmpxchg(entry, old_id, new_id) == old_id) { |
2847 | mem_cgroup_swap_statistics(from, false); |
2848 | mem_cgroup_swap_statistics(to, true); |
2849 | /* |
2850 | * This function is only called from task migration context now. |
2851 | * It postpones res_counter and refcount handling till the end |
2852 | * of task migration(mem_cgroup_clear_mc()) for performance |
2853 | * improvement. But we cannot postpone mem_cgroup_get(to) |
2854 | * because if the process that has been moved to @to does |
2855 | * swap-in, the refcount of @to might be decreased to 0. |
2856 | */ |
2857 | mem_cgroup_get(to); |
2858 | if (need_fixup) { |
2859 | if (!mem_cgroup_is_root(from)) |
2860 | res_counter_uncharge(&from->memsw, PAGE_SIZE); |
2861 | mem_cgroup_put(from); |
2862 | /* |
2863 | * we charged both to->res and to->memsw, so we should |
2864 | * uncharge to->res. |
2865 | */ |
2866 | if (!mem_cgroup_is_root(to)) |
2867 | res_counter_uncharge(&to->res, PAGE_SIZE); |
2868 | } |
2869 | return 0; |
2870 | } |
2871 | return -EINVAL; |
2872 | } |
2873 | #else |
2874 | static inline int mem_cgroup_move_swap_account(swp_entry_t entry, |
2875 | struct mem_cgroup *from, struct mem_cgroup *to, bool need_fixup) |
2876 | { |
2877 | return -EINVAL; |
2878 | } |
2879 | #endif |
2880 | |
2881 | /* |
2882 | * Before starting migration, account PAGE_SIZE to mem_cgroup that the old |
2883 | * page belongs to. |
2884 | */ |
2885 | int mem_cgroup_prepare_migration(struct page *page, |
2886 | struct page *newpage, struct mem_cgroup **ptr) |
2887 | { |
2888 | struct page_cgroup *pc; |
2889 | struct mem_cgroup *mem = NULL; |
2890 | enum charge_type ctype; |
2891 | int ret = 0; |
2892 | |
2893 | VM_BUG_ON(PageTransHuge(page)); |
2894 | if (mem_cgroup_disabled()) |
2895 | return 0; |
2896 | |
2897 | pc = lookup_page_cgroup(page); |
2898 | lock_page_cgroup(pc); |
2899 | if (PageCgroupUsed(pc)) { |
2900 | mem = pc->mem_cgroup; |
2901 | css_get(&mem->css); |
2902 | /* |
2903 | * At migrating an anonymous page, its mapcount goes down |
2904 | * to 0 and uncharge() will be called. But, even if it's fully |
2905 | * unmapped, migration may fail and this page has to be |
2906 | * charged again. We set MIGRATION flag here and delay uncharge |
2907 | * until end_migration() is called |
2908 | * |
2909 | * Corner Case Thinking |
2910 | * A) |
2911 | * When the old page was mapped as Anon and it's unmap-and-freed |
2912 | * while migration was ongoing. |
2913 | * If unmap finds the old page, uncharge() of it will be delayed |
2914 | * until end_migration(). If unmap finds a new page, it's |
2915 | * uncharged when it make mapcount to be 1->0. If unmap code |
2916 | * finds swap_migration_entry, the new page will not be mapped |
2917 | * and end_migration() will find it(mapcount==0). |
2918 | * |
2919 | * B) |
2920 | * When the old page was mapped but migraion fails, the kernel |
2921 | * remaps it. A charge for it is kept by MIGRATION flag even |
2922 | * if mapcount goes down to 0. We can do remap successfully |
2923 | * without charging it again. |
2924 | * |
2925 | * C) |
2926 | * The "old" page is under lock_page() until the end of |
2927 | * migration, so, the old page itself will not be swapped-out. |
2928 | * If the new page is swapped out before end_migraton, our |
2929 | * hook to usual swap-out path will catch the event. |
2930 | */ |
2931 | if (PageAnon(page)) |
2932 | SetPageCgroupMigration(pc); |
2933 | } |
2934 | unlock_page_cgroup(pc); |
2935 | /* |
2936 | * If the page is not charged at this point, |
2937 | * we return here. |
2938 | */ |
2939 | if (!mem) |
2940 | return 0; |
2941 | |
2942 | *ptr = mem; |
2943 | ret = __mem_cgroup_try_charge(NULL, GFP_KERNEL, ptr, false, PAGE_SIZE); |
2944 | css_put(&mem->css);/* drop extra refcnt */ |
2945 | if (ret || *ptr == NULL) { |
2946 | if (PageAnon(page)) { |
2947 | lock_page_cgroup(pc); |
2948 | ClearPageCgroupMigration(pc); |
2949 | unlock_page_cgroup(pc); |
2950 | /* |
2951 | * The old page may be fully unmapped while we kept it. |
2952 | */ |
2953 | mem_cgroup_uncharge_page(page); |
2954 | } |
2955 | return -ENOMEM; |
2956 | } |
2957 | /* |
2958 | * We charge new page before it's used/mapped. So, even if unlock_page() |
2959 | * is called before end_migration, we can catch all events on this new |
2960 | * page. In the case new page is migrated but not remapped, new page's |
2961 | * mapcount will be finally 0 and we call uncharge in end_migration(). |
2962 | */ |
2963 | pc = lookup_page_cgroup(newpage); |
2964 | if (PageAnon(page)) |
2965 | ctype = MEM_CGROUP_CHARGE_TYPE_MAPPED; |
2966 | else if (page_is_file_cache(page)) |
2967 | ctype = MEM_CGROUP_CHARGE_TYPE_CACHE; |
2968 | else |
2969 | ctype = MEM_CGROUP_CHARGE_TYPE_SHMEM; |
2970 | __mem_cgroup_commit_charge(mem, pc, ctype, PAGE_SIZE); |
2971 | return ret; |
2972 | } |
2973 | |
2974 | /* remove redundant charge if migration failed*/ |
2975 | void mem_cgroup_end_migration(struct mem_cgroup *mem, |
2976 | struct page *oldpage, struct page *newpage, bool migration_ok) |
2977 | { |
2978 | struct page *used, *unused; |
2979 | struct page_cgroup *pc; |
2980 | |
2981 | if (!mem) |
2982 | return; |
2983 | /* blocks rmdir() */ |
2984 | cgroup_exclude_rmdir(&mem->css); |
2985 | if (!migration_ok) { |
2986 | used = oldpage; |
2987 | unused = newpage; |
2988 | } else { |
2989 | used = newpage; |
2990 | unused = oldpage; |
2991 | } |
2992 | /* |
2993 | * We disallowed uncharge of pages under migration because mapcount |
2994 | * of the page goes down to zero, temporarly. |
2995 | * Clear the flag and check the page should be charged. |
2996 | */ |
2997 | pc = lookup_page_cgroup(oldpage); |
2998 | lock_page_cgroup(pc); |
2999 | ClearPageCgroupMigration(pc); |
3000 | unlock_page_cgroup(pc); |
3001 | |
3002 | __mem_cgroup_uncharge_common(unused, MEM_CGROUP_CHARGE_TYPE_FORCE); |
3003 | |
3004 | /* |
3005 | * If a page is a file cache, radix-tree replacement is very atomic |
3006 | * and we can skip this check. When it was an Anon page, its mapcount |
3007 | * goes down to 0. But because we added MIGRATION flage, it's not |
3008 | * uncharged yet. There are several case but page->mapcount check |
3009 | * and USED bit check in mem_cgroup_uncharge_page() will do enough |
3010 | * check. (see prepare_charge() also) |
3011 | */ |
3012 | if (PageAnon(used)) |
3013 | mem_cgroup_uncharge_page(used); |
3014 | /* |
3015 | * At migration, we may charge account against cgroup which has no |
3016 | * tasks. |
3017 | * So, rmdir()->pre_destroy() can be called while we do this charge. |
3018 | * In that case, we need to call pre_destroy() again. check it here. |
3019 | */ |
3020 | cgroup_release_and_wakeup_rmdir(&mem->css); |
3021 | } |
3022 | |
3023 | /* |
3024 | * A call to try to shrink memory usage on charge failure at shmem's swapin. |
3025 | * Calling hierarchical_reclaim is not enough because we should update |
3026 | * last_oom_jiffies to prevent pagefault_out_of_memory from invoking global OOM. |
3027 | * Moreover considering hierarchy, we should reclaim from the mem_over_limit, |
3028 | * not from the memcg which this page would be charged to. |
3029 | * try_charge_swapin does all of these works properly. |
3030 | */ |
3031 | int mem_cgroup_shmem_charge_fallback(struct page *page, |
3032 | struct mm_struct *mm, |
3033 | gfp_t gfp_mask) |
3034 | { |
3035 | struct mem_cgroup *mem = NULL; |
3036 | int ret; |
3037 | |
3038 | if (mem_cgroup_disabled()) |
3039 | return 0; |
3040 | |
3041 | ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &mem); |
3042 | if (!ret) |
3043 | mem_cgroup_cancel_charge_swapin(mem); /* it does !mem check */ |
3044 | |
3045 | return ret; |
3046 | } |
3047 | |
3048 | static DEFINE_MUTEX(set_limit_mutex); |
3049 | |
3050 | static int mem_cgroup_resize_limit(struct mem_cgroup *memcg, |
3051 | unsigned long long val) |
3052 | { |
3053 | int retry_count; |
3054 | u64 memswlimit, memlimit; |
3055 | int ret = 0; |
3056 | int children = mem_cgroup_count_children(memcg); |
3057 | u64 curusage, oldusage; |
3058 | int enlarge; |
3059 | |
3060 | /* |
3061 | * For keeping hierarchical_reclaim simple, how long we should retry |
3062 | * is depends on callers. We set our retry-count to be function |
3063 | * of # of children which we should visit in this loop. |
3064 | */ |
3065 | retry_count = MEM_CGROUP_RECLAIM_RETRIES * children; |
3066 | |
3067 | oldusage = res_counter_read_u64(&memcg->res, RES_USAGE); |
3068 | |
3069 | enlarge = 0; |
3070 | while (retry_count) { |
3071 | if (signal_pending(current)) { |
3072 | ret = -EINTR; |
3073 | break; |
3074 | } |
3075 | /* |
3076 | * Rather than hide all in some function, I do this in |
3077 | * open coded manner. You see what this really does. |
3078 | * We have to guarantee mem->res.limit < mem->memsw.limit. |
3079 | */ |
3080 | mutex_lock(&set_limit_mutex); |
3081 | memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT); |
3082 | if (memswlimit < val) { |
3083 | ret = -EINVAL; |
3084 | mutex_unlock(&set_limit_mutex); |
3085 | break; |
3086 | } |
3087 | |
3088 | memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT); |
3089 | if (memlimit < val) |
3090 | enlarge = 1; |
3091 | |
3092 | ret = res_counter_set_limit(&memcg->res, val); |
3093 | if (!ret) { |
3094 | if (memswlimit == val) |
3095 | memcg->memsw_is_minimum = true; |
3096 | else |
3097 | memcg->memsw_is_minimum = false; |
3098 | } |
3099 | mutex_unlock(&set_limit_mutex); |
3100 | |
3101 | if (!ret) |
3102 | break; |
3103 | |
3104 | mem_cgroup_hierarchical_reclaim(memcg, NULL, GFP_KERNEL, |
3105 | MEM_CGROUP_RECLAIM_SHRINK); |
3106 | curusage = res_counter_read_u64(&memcg->res, RES_USAGE); |
3107 | /* Usage is reduced ? */ |
3108 | if (curusage >= oldusage) |
3109 | retry_count--; |
3110 | else |
3111 | oldusage = curusage; |
3112 | } |
3113 | if (!ret && enlarge) |
3114 | memcg_oom_recover(memcg); |
3115 | |
3116 | return ret; |
3117 | } |
3118 | |
3119 | static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg, |
3120 | unsigned long long val) |
3121 | { |
3122 | int retry_count; |
3123 | u64 memlimit, memswlimit, oldusage, curusage; |
3124 | int children = mem_cgroup_count_children(memcg); |
3125 | int ret = -EBUSY; |
3126 | int enlarge = 0; |
3127 | |
3128 | /* see mem_cgroup_resize_res_limit */ |
3129 | retry_count = children * MEM_CGROUP_RECLAIM_RETRIES; |
3130 | oldusage = res_counter_read_u64(&memcg->memsw, RES_USAGE); |
3131 | while (retry_count) { |
3132 | if (signal_pending(current)) { |
3133 | ret = -EINTR; |
3134 | break; |
3135 | } |
3136 | /* |
3137 | * Rather than hide all in some function, I do this in |
3138 | * open coded manner. You see what this really does. |
3139 | * We have to guarantee mem->res.limit < mem->memsw.limit. |
3140 | */ |
3141 | mutex_lock(&set_limit_mutex); |
3142 | memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT); |
3143 | if (memlimit > val) { |
3144 | ret = -EINVAL; |
3145 | mutex_unlock(&set_limit_mutex); |
3146 | break; |
3147 | } |
3148 | memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT); |
3149 | if (memswlimit < val) |
3150 | enlarge = 1; |
3151 | ret = res_counter_set_limit(&memcg->memsw, val); |
3152 | if (!ret) { |
3153 | if (memlimit == val) |
3154 | memcg->memsw_is_minimum = true; |
3155 | else |
3156 | memcg->memsw_is_minimum = false; |
3157 | } |
3158 | mutex_unlock(&set_limit_mutex); |
3159 | |
3160 | if (!ret) |
3161 | break; |
3162 | |
3163 | mem_cgroup_hierarchical_reclaim(memcg, NULL, GFP_KERNEL, |
3164 | MEM_CGROUP_RECLAIM_NOSWAP | |
3165 | MEM_CGROUP_RECLAIM_SHRINK); |
3166 | curusage = res_counter_read_u64(&memcg->memsw, RES_USAGE); |
3167 | /* Usage is reduced ? */ |
3168 | if (curusage >= oldusage) |
3169 | retry_count--; |
3170 | else |
3171 | oldusage = curusage; |
3172 | } |
3173 | if (!ret && enlarge) |
3174 | memcg_oom_recover(memcg); |
3175 | return ret; |
3176 | } |
3177 | |
3178 | unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order, |
3179 | gfp_t gfp_mask) |
3180 | { |
3181 | unsigned long nr_reclaimed = 0; |
3182 | struct mem_cgroup_per_zone *mz, *next_mz = NULL; |
3183 | unsigned long reclaimed; |
3184 | int loop = 0; |
3185 | struct mem_cgroup_tree_per_zone *mctz; |
3186 | unsigned long long excess; |
3187 | |
3188 | if (order > 0) |
3189 | return 0; |
3190 | |
3191 | mctz = soft_limit_tree_node_zone(zone_to_nid(zone), zone_idx(zone)); |
3192 | /* |
3193 | * This loop can run a while, specially if mem_cgroup's continuously |
3194 | * keep exceeding their soft limit and putting the system under |
3195 | * pressure |
3196 | */ |
3197 | do { |
3198 | if (next_mz) |
3199 | mz = next_mz; |
3200 | else |
3201 | mz = mem_cgroup_largest_soft_limit_node(mctz); |
3202 | if (!mz) |
3203 | break; |
3204 | |
3205 | reclaimed = mem_cgroup_hierarchical_reclaim(mz->mem, zone, |
3206 | gfp_mask, |
3207 | MEM_CGROUP_RECLAIM_SOFT); |
3208 | nr_reclaimed += reclaimed; |
3209 | spin_lock(&mctz->lock); |
3210 | |
3211 | /* |
3212 | * If we failed to reclaim anything from this memory cgroup |
3213 | * it is time to move on to the next cgroup |
3214 | */ |
3215 | next_mz = NULL; |
3216 | if (!reclaimed) { |
3217 | do { |
3218 | /* |
3219 | * Loop until we find yet another one. |
3220 | * |
3221 | * By the time we get the soft_limit lock |
3222 | * again, someone might have aded the |
3223 | * group back on the RB tree. Iterate to |
3224 | * make sure we get a different mem. |
3225 | * mem_cgroup_largest_soft_limit_node returns |
3226 | * NULL if no other cgroup is present on |
3227 | * the tree |
3228 | */ |
3229 | next_mz = |
3230 | __mem_cgroup_largest_soft_limit_node(mctz); |
3231 | if (next_mz == mz) { |
3232 | css_put(&next_mz->mem->css); |
3233 | next_mz = NULL; |
3234 | } else /* next_mz == NULL or other memcg */ |
3235 | break; |
3236 | } while (1); |
3237 | } |
3238 | __mem_cgroup_remove_exceeded(mz->mem, mz, mctz); |
3239 | excess = res_counter_soft_limit_excess(&mz->mem->res); |
3240 | /* |
3241 | * One school of thought says that we should not add |
3242 | * back the node to the tree if reclaim returns 0. |
3243 | * But our reclaim could return 0, simply because due |
3244 | * to priority we are exposing a smaller subset of |
3245 | * memory to reclaim from. Consider this as a longer |
3246 | * term TODO. |
3247 | */ |
3248 | /* If excess == 0, no tree ops */ |
3249 | __mem_cgroup_insert_exceeded(mz->mem, mz, mctz, excess); |
3250 | spin_unlock(&mctz->lock); |
3251 | css_put(&mz->mem->css); |
3252 | loop++; |
3253 | /* |
3254 | * Could not reclaim anything and there are no more |
3255 | * mem cgroups to try or we seem to be looping without |
3256 | * reclaiming anything. |
3257 | */ |
3258 | if (!nr_reclaimed && |
3259 | (next_mz == NULL || |
3260 | loop > MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS)) |
3261 | break; |
3262 | } while (!nr_reclaimed); |
3263 | if (next_mz) |
3264 | css_put(&next_mz->mem->css); |
3265 | return nr_reclaimed; |
3266 | } |
3267 | |
3268 | /* |
3269 | * This routine traverse page_cgroup in given list and drop them all. |
3270 | * *And* this routine doesn't reclaim page itself, just removes page_cgroup. |
3271 | */ |
3272 | static int mem_cgroup_force_empty_list(struct mem_cgroup *mem, |
3273 | int node, int zid, enum lru_list lru) |
3274 | { |
3275 | struct zone *zone; |
3276 | struct mem_cgroup_per_zone *mz; |
3277 | struct page_cgroup *pc, *busy; |
3278 | unsigned long flags, loop; |
3279 | struct list_head *list; |
3280 | int ret = 0; |
3281 | |
3282 | zone = &NODE_DATA(node)->node_zones[zid]; |
3283 | mz = mem_cgroup_zoneinfo(mem, node, zid); |
3284 | list = &mz->lists[lru]; |
3285 | |
3286 | loop = MEM_CGROUP_ZSTAT(mz, lru); |
3287 | /* give some margin against EBUSY etc...*/ |
3288 | loop += 256; |
3289 | busy = NULL; |
3290 | while (loop--) { |
3291 | ret = 0; |
3292 | spin_lock_irqsave(&zone->lru_lock, flags); |
3293 | if (list_empty(list)) { |
3294 | spin_unlock_irqrestore(&zone->lru_lock, flags); |
3295 | break; |
3296 | } |
3297 | pc = list_entry(list->prev, struct page_cgroup, lru); |
3298 | if (busy == pc) { |
3299 | list_move(&pc->lru, list); |
3300 | busy = NULL; |
3301 | spin_unlock_irqrestore(&zone->lru_lock, flags); |
3302 | continue; |
3303 | } |
3304 | spin_unlock_irqrestore(&zone->lru_lock, flags); |
3305 | |
3306 | ret = mem_cgroup_move_parent(pc, mem, GFP_KERNEL); |
3307 | if (ret == -ENOMEM) |
3308 | break; |
3309 | |
3310 | if (ret == -EBUSY || ret == -EINVAL) { |
3311 | /* found lock contention or "pc" is obsolete. */ |
3312 | busy = pc; |
3313 | cond_resched(); |
3314 | } else |
3315 | busy = NULL; |
3316 | } |
3317 | |
3318 | if (!ret && !list_empty(list)) |
3319 | return -EBUSY; |
3320 | return ret; |
3321 | } |
3322 | |
3323 | /* |
3324 | * make mem_cgroup's charge to be 0 if there is no task. |
3325 | * This enables deleting this mem_cgroup. |
3326 | */ |
3327 | static int mem_cgroup_force_empty(struct mem_cgroup *mem, bool free_all) |
3328 | { |
3329 | int ret; |
3330 | int node, zid, shrink; |
3331 | int nr_retries = MEM_CGROUP_RECLAIM_RETRIES; |
3332 | struct cgroup *cgrp = mem->css.cgroup; |
3333 | |
3334 | css_get(&mem->css); |
3335 | |
3336 | shrink = 0; |
3337 | /* should free all ? */ |
3338 | if (free_all) |
3339 | goto try_to_free; |
3340 | move_account: |
3341 | do { |
3342 | ret = -EBUSY; |
3343 | if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children)) |
3344 | goto out; |
3345 | ret = -EINTR; |
3346 | if (signal_pending(current)) |
3347 | goto out; |
3348 | /* This is for making all *used* pages to be on LRU. */ |
3349 | lru_add_drain_all(); |
3350 | drain_all_stock_sync(); |
3351 | ret = 0; |
3352 | mem_cgroup_start_move(mem); |
3353 | for_each_node_state(node, N_HIGH_MEMORY) { |
3354 | for (zid = 0; !ret && zid < MAX_NR_ZONES; zid++) { |
3355 | enum lru_list l; |
3356 | for_each_lru(l) { |
3357 | ret = mem_cgroup_force_empty_list(mem, |
3358 | node, zid, l); |
3359 | if (ret) |
3360 | break; |
3361 | } |
3362 | } |
3363 | if (ret) |
3364 | break; |
3365 | } |
3366 | mem_cgroup_end_move(mem); |
3367 | memcg_oom_recover(mem); |
3368 | /* it seems parent cgroup doesn't have enough mem */ |
3369 | if (ret == -ENOMEM) |
3370 | goto try_to_free; |
3371 | cond_resched(); |
3372 | /* "ret" should also be checked to ensure all lists are empty. */ |
3373 | } while (mem->res.usage > 0 || ret); |
3374 | out: |
3375 | css_put(&mem->css); |
3376 | return ret; |
3377 | |
3378 | try_to_free: |
3379 | /* returns EBUSY if there is a task or if we come here twice. */ |
3380 | if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children) || shrink) { |
3381 | ret = -EBUSY; |
3382 | goto out; |
3383 | } |
3384 | /* we call try-to-free pages for make this cgroup empty */ |
3385 | lru_add_drain_all(); |
3386 | /* try to free all pages in this cgroup */ |
3387 | shrink = 1; |
3388 | while (nr_retries && mem->res.usage > 0) { |
3389 | int progress; |
3390 | |
3391 | if (signal_pending(current)) { |
3392 | ret = -EINTR; |
3393 | goto out; |
3394 | } |
3395 | progress = try_to_free_mem_cgroup_pages(mem, GFP_KERNEL, |
3396 | false, get_swappiness(mem)); |
3397 | if (!progress) { |
3398 | nr_retries--; |
3399 | /* maybe some writeback is necessary */ |
3400 | congestion_wait(BLK_RW_ASYNC, HZ/10); |
3401 | } |
3402 | |
3403 | } |
3404 | lru_add_drain(); |
3405 | /* try move_account...there may be some *locked* pages. */ |
3406 | goto move_account; |
3407 | } |
3408 | |
3409 | int mem_cgroup_force_empty_write(struct cgroup *cont, unsigned int event) |
3410 | { |
3411 | return mem_cgroup_force_empty(mem_cgroup_from_cont(cont), true); |
3412 | } |
3413 | |
3414 | |
3415 | static u64 mem_cgroup_hierarchy_read(struct cgroup *cont, struct cftype *cft) |
3416 | { |
3417 | return mem_cgroup_from_cont(cont)->use_hierarchy; |
3418 | } |
3419 | |
3420 | static int mem_cgroup_hierarchy_write(struct cgroup *cont, struct cftype *cft, |
3421 | u64 val) |
3422 | { |
3423 | int retval = 0; |
3424 | struct mem_cgroup *mem = mem_cgroup_from_cont(cont); |
3425 | struct cgroup *parent = cont->parent; |
3426 | struct mem_cgroup *parent_mem = NULL; |
3427 | |
3428 | if (parent) |
3429 | parent_mem = mem_cgroup_from_cont(parent); |
3430 | |
3431 | cgroup_lock(); |
3432 | /* |
3433 | * If parent's use_hierarchy is set, we can't make any modifications |
3434 | * in the child subtrees. If it is unset, then the change can |
3435 | * occur, provided the current cgroup has no children. |
3436 | * |
3437 | * For the root cgroup, parent_mem is NULL, we allow value to be |
3438 | * set if there are no children. |
3439 | */ |
3440 | if ((!parent_mem || !parent_mem->use_hierarchy) && |
3441 | (val == 1 || val == 0)) { |
3442 | if (list_empty(&cont->children)) |
3443 | mem->use_hierarchy = val; |
3444 | else |
3445 | retval = -EBUSY; |
3446 | } else |
3447 | retval = -EINVAL; |
3448 | cgroup_unlock(); |
3449 | |
3450 | return retval; |
3451 | } |
3452 | |
3453 | |
3454 | static u64 mem_cgroup_get_recursive_idx_stat(struct mem_cgroup *mem, |
3455 | enum mem_cgroup_stat_index idx) |
3456 | { |
3457 | struct mem_cgroup *iter; |
3458 | s64 val = 0; |
3459 | |
3460 | /* each per cpu's value can be minus.Then, use s64 */ |
3461 | for_each_mem_cgroup_tree(iter, mem) |
3462 | val += mem_cgroup_read_stat(iter, idx); |
3463 | |
3464 | if (val < 0) /* race ? */ |
3465 | val = 0; |
3466 | return val; |
3467 | } |
3468 | |
3469 | static inline u64 mem_cgroup_usage(struct mem_cgroup *mem, bool swap) |
3470 | { |
3471 | u64 val; |
3472 | |
3473 | if (!mem_cgroup_is_root(mem)) { |
3474 | if (!swap) |
3475 | return res_counter_read_u64(&mem->res, RES_USAGE); |
3476 | else |
3477 | return res_counter_read_u64(&mem->memsw, RES_USAGE); |
3478 | } |
3479 | |
3480 | val = mem_cgroup_get_recursive_idx_stat(mem, MEM_CGROUP_STAT_CACHE); |
3481 | val += mem_cgroup_get_recursive_idx_stat(mem, MEM_CGROUP_STAT_RSS); |
3482 | |
3483 | if (swap) |
3484 | val += mem_cgroup_get_recursive_idx_stat(mem, |
3485 | MEM_CGROUP_STAT_SWAPOUT); |
3486 | |
3487 | return val << PAGE_SHIFT; |
3488 | } |
3489 | |
3490 | static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft) |
3491 | { |
3492 | struct mem_cgroup *mem = mem_cgroup_from_cont(cont); |
3493 | u64 val; |
3494 | int type, name; |
3495 | |
3496 | type = MEMFILE_TYPE(cft->private); |
3497 | name = MEMFILE_ATTR(cft->private); |
3498 | switch (type) { |
3499 | case _MEM: |
3500 | if (name == RES_USAGE) |
3501 | val = mem_cgroup_usage(mem, false); |
3502 | else |
3503 | val = res_counter_read_u64(&mem->res, name); |
3504 | break; |
3505 | case _MEMSWAP: |
3506 | if (name == RES_USAGE) |
3507 | val = mem_cgroup_usage(mem, true); |
3508 | else |
3509 | val = res_counter_read_u64(&mem->memsw, name); |
3510 | break; |
3511 | default: |
3512 | BUG(); |
3513 | break; |
3514 | } |
3515 | return val; |
3516 | } |
3517 | /* |
3518 | * The user of this function is... |
3519 | * RES_LIMIT. |
3520 | */ |
3521 | static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft, |
3522 | const char *buffer) |
3523 | { |
3524 | struct mem_cgroup *memcg = mem_cgroup_from_cont(cont); |
3525 | int type, name; |
3526 | unsigned long long val; |
3527 | int ret; |
3528 | |
3529 | type = MEMFILE_TYPE(cft->private); |
3530 | name = MEMFILE_ATTR(cft->private); |
3531 | switch (name) { |
3532 | case RES_LIMIT: |
3533 | if (mem_cgroup_is_root(memcg)) { /* Can't set limit on root */ |
3534 | ret = -EINVAL; |
3535 | break; |
3536 | } |
3537 | /* This function does all necessary parse...reuse it */ |
3538 | ret = res_counter_memparse_write_strategy(buffer, &val); |
3539 | if (ret) |
3540 | break; |
3541 | if (type == _MEM) |
3542 | ret = mem_cgroup_resize_limit(memcg, val); |
3543 | else |
3544 | ret = mem_cgroup_resize_memsw_limit(memcg, val); |
3545 | break; |
3546 | case RES_SOFT_LIMIT: |
3547 | ret = res_counter_memparse_write_strategy(buffer, &val); |
3548 | if (ret) |
3549 | break; |
3550 | /* |
3551 | * For memsw, soft limits are hard to implement in terms |
3552 | * of semantics, for now, we support soft limits for |
3553 | * control without swap |
3554 | */ |
3555 | if (type == _MEM) |
3556 | ret = res_counter_set_soft_limit(&memcg->res, val); |
3557 | else |
3558 | ret = -EINVAL; |
3559 | break; |
3560 | default: |
3561 | ret = -EINVAL; /* should be BUG() ? */ |
3562 | break; |
3563 | } |
3564 | return ret; |
3565 | } |
3566 | |
3567 | static void memcg_get_hierarchical_limit(struct mem_cgroup *memcg, |
3568 | unsigned long long *mem_limit, unsigned long long *memsw_limit) |
3569 | { |
3570 | struct cgroup *cgroup; |
3571 | unsigned long long min_limit, min_memsw_limit, tmp; |
3572 | |
3573 | min_limit = res_counter_read_u64(&memcg->res, RES_LIMIT); |
3574 | min_memsw_limit = res_counter_read_u64(&memcg->memsw, RES_LIMIT); |
3575 | cgroup = memcg->css.cgroup; |
3576 | if (!memcg->use_hierarchy) |
3577 | goto out; |
3578 | |
3579 | while (cgroup->parent) { |
3580 | cgroup = cgroup->parent; |
3581 | memcg = mem_cgroup_from_cont(cgroup); |
3582 | if (!memcg->use_hierarchy) |
3583 | break; |
3584 | tmp = res_counter_read_u64(&memcg->res, RES_LIMIT); |
3585 | min_limit = min(min_limit, tmp); |
3586 | tmp = res_counter_read_u64(&memcg->memsw, RES_LIMIT); |
3587 | min_memsw_limit = min(min_memsw_limit, tmp); |
3588 | } |
3589 | out: |
3590 | *mem_limit = min_limit; |
3591 | *memsw_limit = min_memsw_limit; |
3592 | return; |
3593 | } |
3594 | |
3595 | static int mem_cgroup_reset(struct cgroup *cont, unsigned int event) |
3596 | { |
3597 | struct mem_cgroup *mem; |
3598 | int type, name; |
3599 | |
3600 | mem = mem_cgroup_from_cont(cont); |
3601 | type = MEMFILE_TYPE(event); |
3602 | name = MEMFILE_ATTR(event); |
3603 | switch (name) { |
3604 | case RES_MAX_USAGE: |
3605 | if (type == _MEM) |
3606 | res_counter_reset_max(&mem->res); |
3607 | else |
3608 | res_counter_reset_max(&mem->memsw); |
3609 | break; |
3610 | case RES_FAILCNT: |
3611 | if (type == _MEM) |
3612 | res_counter_reset_failcnt(&mem->res); |
3613 | else |
3614 | res_counter_reset_failcnt(&mem->memsw); |
3615 | break; |
3616 | } |
3617 | |
3618 | return 0; |
3619 | } |
3620 | |
3621 | static u64 mem_cgroup_move_charge_read(struct cgroup *cgrp, |
3622 | struct cftype *cft) |
3623 | { |
3624 | return mem_cgroup_from_cont(cgrp)->move_charge_at_immigrate; |
3625 | } |
3626 | |
3627 | #ifdef CONFIG_MMU |
3628 | static int mem_cgroup_move_charge_write(struct cgroup *cgrp, |
3629 | struct cftype *cft, u64 val) |
3630 | { |
3631 | struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp); |
3632 | |
3633 | if (val >= (1 << NR_MOVE_TYPE)) |
3634 | return -EINVAL; |
3635 | /* |
3636 | * We check this value several times in both in can_attach() and |
3637 | * attach(), so we need cgroup lock to prevent this value from being |
3638 | * inconsistent. |
3639 | */ |
3640 | cgroup_lock(); |
3641 | mem->move_charge_at_immigrate = val; |
3642 | cgroup_unlock(); |
3643 | |
3644 | return 0; |
3645 | } |
3646 | #else |
3647 | static int mem_cgroup_move_charge_write(struct cgroup *cgrp, |
3648 | struct cftype *cft, u64 val) |
3649 | { |
3650 | return -ENOSYS; |
3651 | } |
3652 | #endif |
3653 | |
3654 | |
3655 | /* For read statistics */ |
3656 | enum { |
3657 | MCS_CACHE, |
3658 | MCS_RSS, |
3659 | MCS_FILE_MAPPED, |
3660 | MCS_PGPGIN, |
3661 | MCS_PGPGOUT, |
3662 | MCS_SWAP, |
3663 | MCS_INACTIVE_ANON, |
3664 | MCS_ACTIVE_ANON, |
3665 | MCS_INACTIVE_FILE, |
3666 | MCS_ACTIVE_FILE, |
3667 | MCS_UNEVICTABLE, |
3668 | NR_MCS_STAT, |
3669 | }; |
3670 | |
3671 | struct mcs_total_stat { |
3672 | s64 stat[NR_MCS_STAT]; |
3673 | }; |
3674 | |
3675 | struct { |
3676 | char *local_name; |
3677 | char *total_name; |
3678 | } memcg_stat_strings[NR_MCS_STAT] = { |
3679 | {"cache", "total_cache"}, |
3680 | {"rss", "total_rss"}, |
3681 | {"mapped_file", "total_mapped_file"}, |
3682 | {"pgpgin", "total_pgpgin"}, |
3683 | {"pgpgout", "total_pgpgout"}, |
3684 | {"swap", "total_swap"}, |
3685 | {"inactive_anon", "total_inactive_anon"}, |
3686 | {"active_anon", "total_active_anon"}, |
3687 | {"inactive_file", "total_inactive_file"}, |
3688 | {"active_file", "total_active_file"}, |
3689 | {"unevictable", "total_unevictable"} |
3690 | }; |
3691 | |
3692 | |
3693 | static void |
3694 | mem_cgroup_get_local_stat(struct mem_cgroup *mem, struct mcs_total_stat *s) |
3695 | { |
3696 | s64 val; |
3697 | |
3698 | /* per cpu stat */ |
3699 | val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_CACHE); |
3700 | s->stat[MCS_CACHE] += val * PAGE_SIZE; |
3701 | val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_RSS); |
3702 | s->stat[MCS_RSS] += val * PAGE_SIZE; |
3703 | val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_FILE_MAPPED); |
3704 | s->stat[MCS_FILE_MAPPED] += val * PAGE_SIZE; |
3705 | val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_PGPGIN_COUNT); |
3706 | s->stat[MCS_PGPGIN] += val; |
3707 | val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_PGPGOUT_COUNT); |
3708 | s->stat[MCS_PGPGOUT] += val; |
3709 | if (do_swap_account) { |
3710 | val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_SWAPOUT); |
3711 | s->stat[MCS_SWAP] += val * PAGE_SIZE; |
3712 | } |
3713 | |
3714 | /* per zone stat */ |
3715 | val = mem_cgroup_get_local_zonestat(mem, LRU_INACTIVE_ANON); |
3716 | s->stat[MCS_INACTIVE_ANON] += val * PAGE_SIZE; |
3717 | val = mem_cgroup_get_local_zonestat(mem, LRU_ACTIVE_ANON); |
3718 | s->stat[MCS_ACTIVE_ANON] += val * PAGE_SIZE; |
3719 | val = mem_cgroup_get_local_zonestat(mem, LRU_INACTIVE_FILE); |
3720 | s->stat[MCS_INACTIVE_FILE] += val * PAGE_SIZE; |
3721 | val = mem_cgroup_get_local_zonestat(mem, LRU_ACTIVE_FILE); |
3722 | s->stat[MCS_ACTIVE_FILE] += val * PAGE_SIZE; |
3723 | val = mem_cgroup_get_local_zonestat(mem, LRU_UNEVICTABLE); |
3724 | s->stat[MCS_UNEVICTABLE] += val * PAGE_SIZE; |
3725 | } |
3726 | |
3727 | static void |
3728 | mem_cgroup_get_total_stat(struct mem_cgroup *mem, struct mcs_total_stat *s) |
3729 | { |
3730 | struct mem_cgroup *iter; |
3731 | |
3732 | for_each_mem_cgroup_tree(iter, mem) |
3733 | mem_cgroup_get_local_stat(iter, s); |
3734 | } |
3735 | |
3736 | static int mem_control_stat_show(struct cgroup *cont, struct cftype *cft, |
3737 | struct cgroup_map_cb *cb) |
3738 | { |
3739 | struct mem_cgroup *mem_cont = mem_cgroup_from_cont(cont); |
3740 | struct mcs_total_stat mystat; |
3741 | int i; |
3742 | |
3743 | memset(&mystat, 0, sizeof(mystat)); |
3744 | mem_cgroup_get_local_stat(mem_cont, &mystat); |
3745 | |
3746 | for (i = 0; i < NR_MCS_STAT; i++) { |
3747 | if (i == MCS_SWAP && !do_swap_account) |
3748 | continue; |
3749 | cb->fill(cb, memcg_stat_strings[i].local_name, mystat.stat[i]); |
3750 | } |
3751 | |
3752 | /* Hierarchical information */ |
3753 | { |
3754 | unsigned long long limit, memsw_limit; |
3755 | memcg_get_hierarchical_limit(mem_cont, &limit, &memsw_limit); |
3756 | cb->fill(cb, "hierarchical_memory_limit", limit); |
3757 | if (do_swap_account) |
3758 | cb->fill(cb, "hierarchical_memsw_limit", memsw_limit); |
3759 | } |
3760 | |
3761 | memset(&mystat, 0, sizeof(mystat)); |
3762 | mem_cgroup_get_total_stat(mem_cont, &mystat); |
3763 | for (i = 0; i < NR_MCS_STAT; i++) { |
3764 | if (i == MCS_SWAP && !do_swap_account) |
3765 | continue; |
3766 | cb->fill(cb, memcg_stat_strings[i].total_name, mystat.stat[i]); |
3767 | } |
3768 | |
3769 | #ifdef CONFIG_DEBUG_VM |
3770 | cb->fill(cb, "inactive_ratio", calc_inactive_ratio(mem_cont, NULL)); |
3771 | |
3772 | { |
3773 | int nid, zid; |
3774 | struct mem_cgroup_per_zone *mz; |
3775 | unsigned long recent_rotated[2] = {0, 0}; |
3776 | unsigned long recent_scanned[2] = {0, 0}; |
3777 | |
3778 | for_each_online_node(nid) |
3779 | for (zid = 0; zid < MAX_NR_ZONES; zid++) { |
3780 | mz = mem_cgroup_zoneinfo(mem_cont, nid, zid); |
3781 | |
3782 | recent_rotated[0] += |
3783 | mz->reclaim_stat.recent_rotated[0]; |
3784 | recent_rotated[1] += |
3785 | mz->reclaim_stat.recent_rotated[1]; |
3786 | recent_scanned[0] += |
3787 | mz->reclaim_stat.recent_scanned[0]; |
3788 | recent_scanned[1] += |
3789 | mz->reclaim_stat.recent_scanned[1]; |
3790 | } |
3791 | cb->fill(cb, "recent_rotated_anon", recent_rotated[0]); |
3792 | cb->fill(cb, "recent_rotated_file", recent_rotated[1]); |
3793 | cb->fill(cb, "recent_scanned_anon", recent_scanned[0]); |
3794 | cb->fill(cb, "recent_scanned_file", recent_scanned[1]); |
3795 | } |
3796 | #endif |
3797 | |
3798 | return 0; |
3799 | } |
3800 | |
3801 | static u64 mem_cgroup_swappiness_read(struct cgroup *cgrp, struct cftype *cft) |
3802 | { |
3803 | struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); |
3804 | |
3805 | return get_swappiness(memcg); |
3806 | } |
3807 | |
3808 | static int mem_cgroup_swappiness_write(struct cgroup *cgrp, struct cftype *cft, |
3809 | u64 val) |
3810 | { |
3811 | struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); |
3812 | struct mem_cgroup *parent; |
3813 | |
3814 | if (val > 100) |
3815 | return -EINVAL; |
3816 | |
3817 | if (cgrp->parent == NULL) |
3818 | return -EINVAL; |
3819 | |
3820 | parent = mem_cgroup_from_cont(cgrp->parent); |
3821 | |
3822 | cgroup_lock(); |
3823 | |
3824 | /* If under hierarchy, only empty-root can set this value */ |
3825 | if ((parent->use_hierarchy) || |
3826 | (memcg->use_hierarchy && !list_empty(&cgrp->children))) { |
3827 | cgroup_unlock(); |
3828 | return -EINVAL; |
3829 | } |
3830 | |
3831 | spin_lock(&memcg->reclaim_param_lock); |
3832 | memcg->swappiness = val; |
3833 | spin_unlock(&memcg->reclaim_param_lock); |
3834 | |
3835 | cgroup_unlock(); |
3836 | |
3837 | return 0; |
3838 | } |
3839 | |
3840 | static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap) |
3841 | { |
3842 | struct mem_cgroup_threshold_ary *t; |
3843 | u64 usage; |
3844 | int i; |
3845 | |
3846 | rcu_read_lock(); |
3847 | if (!swap) |
3848 | t = rcu_dereference(memcg->thresholds.primary); |
3849 | else |
3850 | t = rcu_dereference(memcg->memsw_thresholds.primary); |
3851 | |
3852 | if (!t) |
3853 | goto unlock; |
3854 | |
3855 | usage = mem_cgroup_usage(memcg, swap); |
3856 | |
3857 | /* |
3858 | * current_threshold points to threshold just below usage. |
3859 | * If it's not true, a threshold was crossed after last |
3860 | * call of __mem_cgroup_threshold(). |
3861 | */ |
3862 | i = t->current_threshold; |
3863 | |
3864 | /* |
3865 | * Iterate backward over array of thresholds starting from |
3866 | * current_threshold and check if a threshold is crossed. |
3867 | * If none of thresholds below usage is crossed, we read |
3868 | * only one element of the array here. |
3869 | */ |
3870 | for (; i >= 0 && unlikely(t->entries[i].threshold > usage); i--) |
3871 | eventfd_signal(t->entries[i].eventfd, 1); |
3872 | |
3873 | /* i = current_threshold + 1 */ |
3874 | i++; |
3875 | |
3876 | /* |
3877 | * Iterate forward over array of thresholds starting from |
3878 | * current_threshold+1 and check if a threshold is crossed. |
3879 | * If none of thresholds above usage is crossed, we read |
3880 | * only one element of the array here. |
3881 | */ |
3882 | for (; i < t->size && unlikely(t->entries[i].threshold <= usage); i++) |
3883 | eventfd_signal(t->entries[i].eventfd, 1); |
3884 | |
3885 | /* Update current_threshold */ |
3886 | t->current_threshold = i - 1; |
3887 | unlock: |
3888 | rcu_read_unlock(); |
3889 | } |
3890 | |
3891 | static void mem_cgroup_threshold(struct mem_cgroup *memcg) |
3892 | { |
3893 | while (memcg) { |
3894 | __mem_cgroup_threshold(memcg, false); |
3895 | if (do_swap_account) |
3896 | __mem_cgroup_threshold(memcg, true); |
3897 | |
3898 | memcg = parent_mem_cgroup(memcg); |
3899 | } |
3900 | } |
3901 | |
3902 | static int compare_thresholds(const void *a, const void *b) |
3903 | { |
3904 | const struct mem_cgroup_threshold *_a = a; |
3905 | const struct mem_cgroup_threshold *_b = b; |
3906 | |
3907 | return _a->threshold - _b->threshold; |
3908 | } |
3909 | |
3910 | static int mem_cgroup_oom_notify_cb(struct mem_cgroup *mem) |
3911 | { |
3912 | struct mem_cgroup_eventfd_list *ev; |
3913 | |
3914 | list_for_each_entry(ev, &mem->oom_notify, list) |
3915 | eventfd_signal(ev->eventfd, 1); |
3916 | return 0; |
3917 | } |
3918 | |
3919 | static void mem_cgroup_oom_notify(struct mem_cgroup *mem) |
3920 | { |
3921 | struct mem_cgroup *iter; |
3922 | |
3923 | for_each_mem_cgroup_tree(iter, mem) |
3924 | mem_cgroup_oom_notify_cb(iter); |
3925 | } |
3926 | |
3927 | static int mem_cgroup_usage_register_event(struct cgroup *cgrp, |
3928 | struct cftype *cft, struct eventfd_ctx *eventfd, const char *args) |
3929 | { |
3930 | struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); |
3931 | struct mem_cgroup_thresholds *thresholds; |
3932 | struct mem_cgroup_threshold_ary *new; |
3933 | int type = MEMFILE_TYPE(cft->private); |
3934 | u64 threshold, usage; |
3935 | int i, size, ret; |
3936 | |
3937 | ret = res_counter_memparse_write_strategy(args, &threshold); |
3938 | if (ret) |
3939 | return ret; |
3940 | |
3941 | mutex_lock(&memcg->thresholds_lock); |
3942 | |
3943 | if (type == _MEM) |
3944 | thresholds = &memcg->thresholds; |
3945 | else if (type == _MEMSWAP) |
3946 | thresholds = &memcg->memsw_thresholds; |
3947 | else |
3948 | BUG(); |
3949 | |
3950 | usage = mem_cgroup_usage(memcg, type == _MEMSWAP); |
3951 | |
3952 | /* Check if a threshold crossed before adding a new one */ |
3953 | if (thresholds->primary) |
3954 | __mem_cgroup_threshold(memcg, type == _MEMSWAP); |
3955 | |
3956 | size = thresholds->primary ? thresholds->primary->size + 1 : 1; |
3957 | |
3958 | /* Allocate memory for new array of thresholds */ |
3959 | new = kmalloc(sizeof(*new) + size * sizeof(struct mem_cgroup_threshold), |
3960 | GFP_KERNEL); |
3961 | if (!new) { |
3962 | ret = -ENOMEM; |
3963 | goto unlock; |
3964 | } |
3965 | new->size = size; |
3966 | |
3967 | /* Copy thresholds (if any) to new array */ |
3968 | if (thresholds->primary) { |
3969 | memcpy(new->entries, thresholds->primary->entries, (size - 1) * |
3970 | sizeof(struct mem_cgroup_threshold)); |
3971 | } |
3972 | |
3973 | /* Add new threshold */ |
3974 | new->entries[size - 1].eventfd = eventfd; |
3975 | new->entries[size - 1].threshold = threshold; |
3976 | |
3977 | /* Sort thresholds. Registering of new threshold isn't time-critical */ |
3978 | sort(new->entries, size, sizeof(struct mem_cgroup_threshold), |
3979 | compare_thresholds, NULL); |
3980 | |
3981 | /* Find current threshold */ |
3982 | new->current_threshold = -1; |
3983 | for (i = 0; i < size; i++) { |
3984 | if (new->entries[i].threshold < usage) { |
3985 | /* |
3986 | * new->current_threshold will not be used until |
3987 | * rcu_assign_pointer(), so it's safe to increment |
3988 | * it here. |
3989 | */ |
3990 | ++new->current_threshold; |
3991 | } |
3992 | } |
3993 | |
3994 | /* Free old spare buffer and save old primary buffer as spare */ |
3995 | kfree(thresholds->spare); |
3996 | thresholds->spare = thresholds->primary; |
3997 | |
3998 | rcu_assign_pointer(thresholds->primary, new); |
3999 | |
4000 | /* To be sure that nobody uses thresholds */ |
4001 | synchronize_rcu(); |
4002 | |
4003 | unlock: |
4004 | mutex_unlock(&memcg->thresholds_lock); |
4005 | |
4006 | return ret; |
4007 | } |
4008 | |
4009 | static void mem_cgroup_usage_unregister_event(struct cgroup *cgrp, |
4010 | struct cftype *cft, struct eventfd_ctx *eventfd) |
4011 | { |
4012 | struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); |
4013 | struct mem_cgroup_thresholds *thresholds; |
4014 | struct mem_cgroup_threshold_ary *new; |
4015 | int type = MEMFILE_TYPE(cft->private); |
4016 | u64 usage; |
4017 | int i, j, size; |
4018 | |
4019 | mutex_lock(&memcg->thresholds_lock); |
4020 | if (type == _MEM) |
4021 | thresholds = &memcg->thresholds; |
4022 | else if (type == _MEMSWAP) |
4023 | thresholds = &memcg->memsw_thresholds; |
4024 | else |
4025 | BUG(); |
4026 | |
4027 | /* |
4028 | * Something went wrong if we trying to unregister a threshold |
4029 | * if we don't have thresholds |
4030 | */ |
4031 | BUG_ON(!thresholds); |
4032 | |
4033 | usage = mem_cgroup_usage(memcg, type == _MEMSWAP); |
4034 | |
4035 | /* Check if a threshold crossed before removing */ |
4036 | __mem_cgroup_threshold(memcg, type == _MEMSWAP); |
4037 | |
4038 | /* Calculate new number of threshold */ |
4039 | size = 0; |
4040 | for (i = 0; i < thresholds->primary->size; i++) { |
4041 | if (thresholds->primary->entries[i].eventfd != eventfd) |
4042 | size++; |
4043 | } |
4044 | |
4045 | new = thresholds->spare; |
4046 | |
4047 | /* Set thresholds array to NULL if we don't have thresholds */ |
4048 | if (!size) { |
4049 | kfree(new); |
4050 | new = NULL; |
4051 | goto swap_buffers; |
4052 | } |
4053 | |
4054 | new->size = size; |
4055 | |
4056 | /* Copy thresholds and find current threshold */ |
4057 | new->current_threshold = -1; |
4058 | for (i = 0, j = 0; i < thresholds->primary->size; i++) { |
4059 | if (thresholds->primary->entries[i].eventfd == eventfd) |
4060 | continue; |
4061 | |
4062 | new->entries[j] = thresholds->primary->entries[i]; |
4063 | if (new->entries[j].threshold < usage) { |
4064 | /* |
4065 | * new->current_threshold will not be used |
4066 | * until rcu_assign_pointer(), so it's safe to increment |
4067 | * it here. |
4068 | */ |
4069 | ++new->current_threshold; |
4070 | } |
4071 | j++; |
4072 | } |
4073 | |
4074 | swap_buffers: |
4075 | /* Swap primary and spare array */ |
4076 | thresholds->spare = thresholds->primary; |
4077 | rcu_assign_pointer(thresholds->primary, new); |
4078 | |
4079 | /* To be sure that nobody uses thresholds */ |
4080 | synchronize_rcu(); |
4081 | |
4082 | mutex_unlock(&memcg->thresholds_lock); |
4083 | } |
4084 | |
4085 | static int mem_cgroup_oom_register_event(struct cgroup *cgrp, |
4086 | struct cftype *cft, struct eventfd_ctx *eventfd, const char *args) |
4087 | { |
4088 | struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); |
4089 | struct mem_cgroup_eventfd_list *event; |
4090 | int type = MEMFILE_TYPE(cft->private); |
4091 | |
4092 | BUG_ON(type != _OOM_TYPE); |
4093 | event = kmalloc(sizeof(*event), GFP_KERNEL); |
4094 | if (!event) |
4095 | return -ENOMEM; |
4096 | |
4097 | mutex_lock(&memcg_oom_mutex); |
4098 | |
4099 | event->eventfd = eventfd; |
4100 | list_add(&event->list, &memcg->oom_notify); |
4101 | |
4102 | /* already in OOM ? */ |
4103 | if (atomic_read(&memcg->oom_lock)) |
4104 | eventfd_signal(eventfd, 1); |
4105 | mutex_unlock(&memcg_oom_mutex); |
4106 | |
4107 | return 0; |
4108 | } |
4109 | |
4110 | static void mem_cgroup_oom_unregister_event(struct cgroup *cgrp, |
4111 | struct cftype *cft, struct eventfd_ctx *eventfd) |
4112 | { |
4113 | struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp); |
4114 | struct mem_cgroup_eventfd_list *ev, *tmp; |
4115 | int type = MEMFILE_TYPE(cft->private); |
4116 | |
4117 | BUG_ON(type != _OOM_TYPE); |
4118 | |
4119 | mutex_lock(&memcg_oom_mutex); |
4120 | |
4121 | list_for_each_entry_safe(ev, tmp, &mem->oom_notify, list) { |
4122 | if (ev->eventfd == eventfd) { |
4123 | list_del(&ev->list); |
4124 | kfree(ev); |
4125 | } |
4126 | } |
4127 | |
4128 | mutex_unlock(&memcg_oom_mutex); |
4129 | } |
4130 | |
4131 | static int mem_cgroup_oom_control_read(struct cgroup *cgrp, |
4132 | struct cftype *cft, struct cgroup_map_cb *cb) |
4133 | { |
4134 | struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp); |
4135 | |
4136 | cb->fill(cb, "oom_kill_disable", mem->oom_kill_disable); |
4137 | |
4138 | if (atomic_read(&mem->oom_lock)) |
4139 | cb->fill(cb, "under_oom", 1); |
4140 | else |
4141 | cb->fill(cb, "under_oom", 0); |
4142 | return 0; |
4143 | } |
4144 | |
4145 | static int mem_cgroup_oom_control_write(struct cgroup *cgrp, |
4146 | struct cftype *cft, u64 val) |
4147 | { |
4148 | struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp); |
4149 | struct mem_cgroup *parent; |
4150 | |
4151 | /* cannot set to root cgroup and only 0 and 1 are allowed */ |
4152 | if (!cgrp->parent || !((val == 0) || (val == 1))) |
4153 | return -EINVAL; |
4154 | |
4155 | parent = mem_cgroup_from_cont(cgrp->parent); |
4156 | |
4157 | cgroup_lock(); |
4158 | /* oom-kill-disable is a flag for subhierarchy. */ |
4159 | if ((parent->use_hierarchy) || |
4160 | (mem->use_hierarchy && !list_empty(&cgrp->children))) { |
4161 | cgroup_unlock(); |
4162 | return -EINVAL; |
4163 | } |
4164 | mem->oom_kill_disable = val; |
4165 | if (!val) |
4166 | memcg_oom_recover(mem); |
4167 | cgroup_unlock(); |
4168 | return 0; |
4169 | } |
4170 | |
4171 | static struct cftype mem_cgroup_files[] = { |
4172 | { |
4173 | .name = "usage_in_bytes", |
4174 | .private = MEMFILE_PRIVATE(_MEM, RES_USAGE), |
4175 | .read_u64 = mem_cgroup_read, |
4176 | .register_event = mem_cgroup_usage_register_event, |
4177 | .unregister_event = mem_cgroup_usage_unregister_event, |
4178 | }, |
4179 | { |
4180 | .name = "max_usage_in_bytes", |
4181 | .private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE), |
4182 | .trigger = mem_cgroup_reset, |
4183 | .read_u64 = mem_cgroup_read, |
4184 | }, |
4185 | { |
4186 | .name = "limit_in_bytes", |
4187 | .private = MEMFILE_PRIVATE(_MEM, RES_LIMIT), |
4188 | .write_string = mem_cgroup_write, |
4189 | .read_u64 = mem_cgroup_read, |
4190 | }, |
4191 | { |
4192 | .name = "soft_limit_in_bytes", |
4193 | .private = MEMFILE_PRIVATE(_MEM, RES_SOFT_LIMIT), |
4194 | .write_string = mem_cgroup_write, |
4195 | .read_u64 = mem_cgroup_read, |
4196 | }, |
4197 | { |
4198 | .name = "failcnt", |
4199 | .private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT), |
4200 | .trigger = mem_cgroup_reset, |
4201 | .read_u64 = mem_cgroup_read, |
4202 | }, |
4203 | { |
4204 | .name = "stat", |
4205 | .read_map = mem_control_stat_show, |
4206 | }, |
4207 | { |
4208 | .name = "force_empty", |
4209 | .trigger = mem_cgroup_force_empty_write, |
4210 | }, |
4211 | { |
4212 | .name = "use_hierarchy", |
4213 | .write_u64 = mem_cgroup_hierarchy_write, |
4214 | .read_u64 = mem_cgroup_hierarchy_read, |
4215 | }, |
4216 | { |
4217 | .name = "swappiness", |
4218 | .read_u64 = mem_cgroup_swappiness_read, |
4219 | .write_u64 = mem_cgroup_swappiness_write, |
4220 | }, |
4221 | { |
4222 | .name = "move_charge_at_immigrate", |
4223 | .read_u64 = mem_cgroup_move_charge_read, |
4224 | .write_u64 = mem_cgroup_move_charge_write, |
4225 | }, |
4226 | { |
4227 | .name = "oom_control", |
4228 | .read_map = mem_cgroup_oom_control_read, |
4229 | .write_u64 = mem_cgroup_oom_control_write, |
4230 | .register_event = mem_cgroup_oom_register_event, |
4231 | .unregister_event = mem_cgroup_oom_unregister_event, |
4232 | .private = MEMFILE_PRIVATE(_OOM_TYPE, OOM_CONTROL), |
4233 | }, |
4234 | }; |
4235 | |
4236 | #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP |
4237 | static struct cftype memsw_cgroup_files[] = { |
4238 | { |
4239 | .name = "memsw.usage_in_bytes", |
4240 | .private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE), |
4241 | .read_u64 = mem_cgroup_read, |
4242 | .register_event = mem_cgroup_usage_register_event, |
4243 | .unregister_event = mem_cgroup_usage_unregister_event, |
4244 | }, |
4245 | { |
4246 | .name = "memsw.max_usage_in_bytes", |
4247 | .private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE), |
4248 | .trigger = mem_cgroup_reset, |
4249 | .read_u64 = mem_cgroup_read, |
4250 | }, |
4251 | { |
4252 | .name = "memsw.limit_in_bytes", |
4253 | .private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT), |
4254 | .write_string = mem_cgroup_write, |
4255 | .read_u64 = mem_cgroup_read, |
4256 | }, |
4257 | { |
4258 | .name = "memsw.failcnt", |
4259 | .private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT), |
4260 | .trigger = mem_cgroup_reset, |
4261 | .read_u64 = mem_cgroup_read, |
4262 | }, |
4263 | }; |
4264 | |
4265 | static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss) |
4266 | { |
4267 | if (!do_swap_account) |
4268 | return 0; |
4269 | return cgroup_add_files(cont, ss, memsw_cgroup_files, |
4270 | ARRAY_SIZE(memsw_cgroup_files)); |
4271 | }; |
4272 | #else |
4273 | static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss) |
4274 | { |
4275 | return 0; |
4276 | } |
4277 | #endif |
4278 | |
4279 | static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node) |
4280 | { |
4281 | struct mem_cgroup_per_node *pn; |
4282 | struct mem_cgroup_per_zone *mz; |
4283 | enum lru_list l; |
4284 | int zone, tmp = node; |
4285 | /* |
4286 | * This routine is called against possible nodes. |
4287 | * But it's BUG to call kmalloc() against offline node. |
4288 | * |
4289 | * TODO: this routine can waste much memory for nodes which will |
4290 | * never be onlined. It's better to use memory hotplug callback |
4291 | * function. |
4292 | */ |
4293 | if (!node_state(node, N_NORMAL_MEMORY)) |
4294 | tmp = -1; |
4295 | pn = kzalloc_node(sizeof(*pn), GFP_KERNEL, tmp); |
4296 | if (!pn) |
4297 | return 1; |
4298 | |
4299 | mem->info.nodeinfo[node] = pn; |
4300 | for (zone = 0; zone < MAX_NR_ZONES; zone++) { |
4301 | mz = &pn->zoneinfo[zone]; |
4302 | for_each_lru(l) |
4303 | INIT_LIST_HEAD(&mz->lists[l]); |
4304 | mz->usage_in_excess = 0; |
4305 | mz->on_tree = false; |
4306 | mz->mem = mem; |
4307 | } |
4308 | return 0; |
4309 | } |
4310 | |
4311 | static void free_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node) |
4312 | { |
4313 | kfree(mem->info.nodeinfo[node]); |
4314 | } |
4315 | |
4316 | static struct mem_cgroup *mem_cgroup_alloc(void) |
4317 | { |
4318 | struct mem_cgroup *mem; |
4319 | int size = sizeof(struct mem_cgroup); |
4320 | |
4321 | /* Can be very big if MAX_NUMNODES is very big */ |
4322 | if (size < PAGE_SIZE) |
4323 | mem = kzalloc(size, GFP_KERNEL); |
4324 | else |
4325 | mem = vzalloc(size); |
4326 | |
4327 | if (!mem) |
4328 | return NULL; |
4329 | |
4330 | mem->stat = alloc_percpu(struct mem_cgroup_stat_cpu); |
4331 | if (!mem->stat) |
4332 | goto out_free; |
4333 | spin_lock_init(&mem->pcp_counter_lock); |
4334 | return mem; |
4335 | |
4336 | out_free: |
4337 | if (size < PAGE_SIZE) |
4338 | kfree(mem); |
4339 | else |
4340 | vfree(mem); |
4341 | return NULL; |
4342 | } |
4343 | |
4344 | /* |
4345 | * At destroying mem_cgroup, references from swap_cgroup can remain. |
4346 | * (scanning all at force_empty is too costly...) |
4347 | * |
4348 | * Instead of clearing all references at force_empty, we remember |
4349 | * the number of reference from swap_cgroup and free mem_cgroup when |
4350 | * it goes down to 0. |
4351 | * |
4352 | * Removal of cgroup itself succeeds regardless of refs from swap. |
4353 | */ |
4354 | |
4355 | static void __mem_cgroup_free(struct mem_cgroup *mem) |
4356 | { |
4357 | int node; |
4358 | |
4359 | mem_cgroup_remove_from_trees(mem); |
4360 | free_css_id(&mem_cgroup_subsys, &mem->css); |
4361 | |
4362 | for_each_node_state(node, N_POSSIBLE) |
4363 | free_mem_cgroup_per_zone_info(mem, node); |
4364 | |
4365 | free_percpu(mem->stat); |
4366 | if (sizeof(struct mem_cgroup) < PAGE_SIZE) |
4367 | kfree(mem); |
4368 | else |
4369 | vfree(mem); |
4370 | } |
4371 | |
4372 | static void mem_cgroup_get(struct mem_cgroup *mem) |
4373 | { |
4374 | atomic_inc(&mem->refcnt); |
4375 | } |
4376 | |
4377 | static void __mem_cgroup_put(struct mem_cgroup *mem, int count) |
4378 | { |
4379 | if (atomic_sub_and_test(count, &mem->refcnt)) { |
4380 | struct mem_cgroup *parent = parent_mem_cgroup(mem); |
4381 | __mem_cgroup_free(mem); |
4382 | if (parent) |
4383 | mem_cgroup_put(parent); |
4384 | } |
4385 | } |
4386 | |
4387 | static void mem_cgroup_put(struct mem_cgroup *mem) |
4388 | { |
4389 | __mem_cgroup_put(mem, 1); |
4390 | } |
4391 | |
4392 | /* |
4393 | * Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled. |
4394 | */ |
4395 | static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem) |
4396 | { |
4397 | if (!mem->res.parent) |
4398 | return NULL; |
4399 | return mem_cgroup_from_res_counter(mem->res.parent, res); |
4400 | } |
4401 | |
4402 | #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP |
4403 | static void __init enable_swap_cgroup(void) |
4404 | { |
4405 | if (!mem_cgroup_disabled() && really_do_swap_account) |
4406 | do_swap_account = 1; |
4407 | } |
4408 | #else |
4409 | static void __init enable_swap_cgroup(void) |
4410 | { |
4411 | } |
4412 | #endif |
4413 | |
4414 | static int mem_cgroup_soft_limit_tree_init(void) |
4415 | { |
4416 | struct mem_cgroup_tree_per_node *rtpn; |
4417 | struct mem_cgroup_tree_per_zone *rtpz; |
4418 | int tmp, node, zone; |
4419 | |
4420 | for_each_node_state(node, N_POSSIBLE) { |
4421 | tmp = node; |
4422 | if (!node_state(node, N_NORMAL_MEMORY)) |
4423 | tmp = -1; |
4424 | rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL, tmp); |
4425 | if (!rtpn) |
4426 | return 1; |
4427 | |
4428 | soft_limit_tree.rb_tree_per_node[node] = rtpn; |
4429 | |
4430 | for (zone = 0; zone < MAX_NR_ZONES; zone++) { |
4431 | rtpz = &rtpn->rb_tree_per_zone[zone]; |
4432 | rtpz->rb_root = RB_ROOT; |
4433 | spin_lock_init(&rtpz->lock); |
4434 | } |
4435 | } |
4436 | return 0; |
4437 | } |
4438 | |
4439 | static struct cgroup_subsys_state * __ref |
4440 | mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont) |
4441 | { |
4442 | struct mem_cgroup *mem, *parent; |
4443 | long error = -ENOMEM; |
4444 | int node; |
4445 | |
4446 | mem = mem_cgroup_alloc(); |
4447 | if (!mem) |
4448 | return ERR_PTR(error); |
4449 | |
4450 | for_each_node_state(node, N_POSSIBLE) |
4451 | if (alloc_mem_cgroup_per_zone_info(mem, node)) |
4452 | goto free_out; |
4453 | |
4454 | /* root ? */ |
4455 | if (cont->parent == NULL) { |
4456 | int cpu; |
4457 | enable_swap_cgroup(); |
4458 | parent = NULL; |
4459 | root_mem_cgroup = mem; |
4460 | if (mem_cgroup_soft_limit_tree_init()) |
4461 | goto free_out; |
4462 | for_each_possible_cpu(cpu) { |
4463 | struct memcg_stock_pcp *stock = |
4464 | &per_cpu(memcg_stock, cpu); |
4465 | INIT_WORK(&stock->work, drain_local_stock); |
4466 | } |
4467 | hotcpu_notifier(memcg_cpu_hotplug_callback, 0); |
4468 | } else { |
4469 | parent = mem_cgroup_from_cont(cont->parent); |
4470 | mem->use_hierarchy = parent->use_hierarchy; |
4471 | mem->oom_kill_disable = parent->oom_kill_disable; |
4472 | } |
4473 | |
4474 | if (parent && parent->use_hierarchy) { |
4475 | res_counter_init(&mem->res, &parent->res); |
4476 | res_counter_init(&mem->memsw, &parent->memsw); |
4477 | /* |
4478 | * We increment refcnt of the parent to ensure that we can |
4479 | * safely access it on res_counter_charge/uncharge. |
4480 | * This refcnt will be decremented when freeing this |
4481 | * mem_cgroup(see mem_cgroup_put). |
4482 | */ |
4483 | mem_cgroup_get(parent); |
4484 | } else { |
4485 | res_counter_init(&mem->res, NULL); |
4486 | res_counter_init(&mem->memsw, NULL); |
4487 | } |
4488 | mem->last_scanned_child = 0; |
4489 | spin_lock_init(&mem->reclaim_param_lock); |
4490 | INIT_LIST_HEAD(&mem->oom_notify); |
4491 | |
4492 | if (parent) |
4493 | mem->swappiness = get_swappiness(parent); |
4494 | atomic_set(&mem->refcnt, 1); |
4495 | mem->move_charge_at_immigrate = 0; |
4496 | mutex_init(&mem->thresholds_lock); |
4497 | return &mem->css; |
4498 | free_out: |
4499 | __mem_cgroup_free(mem); |
4500 | root_mem_cgroup = NULL; |
4501 | return ERR_PTR(error); |
4502 | } |
4503 | |
4504 | static int mem_cgroup_pre_destroy(struct cgroup_subsys *ss, |
4505 | struct cgroup *cont) |
4506 | { |
4507 | struct mem_cgroup *mem = mem_cgroup_from_cont(cont); |
4508 | |
4509 | return mem_cgroup_force_empty(mem, false); |
4510 | } |
4511 | |
4512 | static void mem_cgroup_destroy(struct cgroup_subsys *ss, |
4513 | struct cgroup *cont) |
4514 | { |
4515 | struct mem_cgroup *mem = mem_cgroup_from_cont(cont); |
4516 | |
4517 | mem_cgroup_put(mem); |
4518 | } |
4519 | |
4520 | static int mem_cgroup_populate(struct cgroup_subsys *ss, |
4521 | struct cgroup *cont) |
4522 | { |
4523 | int ret; |
4524 | |
4525 | ret = cgroup_add_files(cont, ss, mem_cgroup_files, |
4526 | ARRAY_SIZE(mem_cgroup_files)); |
4527 | |
4528 | if (!ret) |
4529 | ret = register_memsw_files(cont, ss); |
4530 | return ret; |
4531 | } |
4532 | |
4533 | #ifdef CONFIG_MMU |
4534 | /* Handlers for move charge at task migration. */ |
4535 | #define PRECHARGE_COUNT_AT_ONCE 256 |
4536 | static int mem_cgroup_do_precharge(unsigned long count) |
4537 | { |
4538 | int ret = 0; |
4539 | int batch_count = PRECHARGE_COUNT_AT_ONCE; |
4540 | struct mem_cgroup *mem = mc.to; |
4541 | |
4542 | if (mem_cgroup_is_root(mem)) { |
4543 | mc.precharge += count; |
4544 | /* we don't need css_get for root */ |
4545 | return ret; |
4546 | } |
4547 | /* try to charge at once */ |
4548 | if (count > 1) { |
4549 | struct res_counter *dummy; |
4550 | /* |
4551 | * "mem" cannot be under rmdir() because we've already checked |
4552 | * by cgroup_lock_live_cgroup() that it is not removed and we |
4553 | * are still under the same cgroup_mutex. So we can postpone |
4554 | * css_get(). |
4555 | */ |
4556 | if (res_counter_charge(&mem->res, PAGE_SIZE * count, &dummy)) |
4557 | goto one_by_one; |
4558 | if (do_swap_account && res_counter_charge(&mem->memsw, |
4559 | PAGE_SIZE * count, &dummy)) { |
4560 | res_counter_uncharge(&mem->res, PAGE_SIZE * count); |
4561 | goto one_by_one; |
4562 | } |
4563 | mc.precharge += count; |
4564 | return ret; |
4565 | } |
4566 | one_by_one: |
4567 | /* fall back to one by one charge */ |
4568 | while (count--) { |
4569 | if (signal_pending(current)) { |
4570 | ret = -EINTR; |
4571 | break; |
4572 | } |
4573 | if (!batch_count--) { |
4574 | batch_count = PRECHARGE_COUNT_AT_ONCE; |
4575 | cond_resched(); |
4576 | } |
4577 | ret = __mem_cgroup_try_charge(NULL, GFP_KERNEL, &mem, false, |
4578 | PAGE_SIZE); |
4579 | if (ret || !mem) |
4580 | /* mem_cgroup_clear_mc() will do uncharge later */ |
4581 | return -ENOMEM; |
4582 | mc.precharge++; |
4583 | } |
4584 | return ret; |
4585 | } |
4586 | |
4587 | /** |
4588 | * is_target_pte_for_mc - check a pte whether it is valid for move charge |
4589 | * @vma: the vma the pte to be checked belongs |
4590 | * @addr: the address corresponding to the pte to be checked |
4591 | * @ptent: the pte to be checked |
4592 | * @target: the pointer the target page or swap ent will be stored(can be NULL) |
4593 | * |
4594 | * Returns |
4595 | * 0(MC_TARGET_NONE): if the pte is not a target for move charge. |
4596 | * 1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for |
4597 | * move charge. if @target is not NULL, the page is stored in target->page |
4598 | * with extra refcnt got(Callers should handle it). |
4599 | * 2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a |
4600 | * target for charge migration. if @target is not NULL, the entry is stored |
4601 | * in target->ent. |
4602 | * |
4603 | * Called with pte lock held. |
4604 | */ |
4605 | union mc_target { |
4606 | struct page *page; |
4607 | swp_entry_t ent; |
4608 | }; |
4609 | |
4610 | enum mc_target_type { |
4611 | MC_TARGET_NONE, /* not used */ |
4612 | MC_TARGET_PAGE, |
4613 | MC_TARGET_SWAP, |
4614 | }; |
4615 | |
4616 | static struct page *mc_handle_present_pte(struct vm_area_struct *vma, |
4617 | unsigned long addr, pte_t ptent) |
4618 | { |
4619 | struct page *page = vm_normal_page(vma, addr, ptent); |
4620 | |
4621 | if (!page || !page_mapped(page)) |
4622 | return NULL; |
4623 | if (PageAnon(page)) { |
4624 | /* we don't move shared anon */ |
4625 | if (!move_anon() || page_mapcount(page) > 2) |
4626 | return NULL; |
4627 | } else if (!move_file()) |
4628 | /* we ignore mapcount for file pages */ |
4629 | return NULL; |
4630 | if (!get_page_unless_zero(page)) |
4631 | return NULL; |
4632 | |
4633 | return page; |
4634 | } |
4635 | |
4636 | static struct page *mc_handle_swap_pte(struct vm_area_struct *vma, |
4637 | unsigned long addr, pte_t ptent, swp_entry_t *entry) |
4638 | { |
4639 | int usage_count; |
4640 | struct page *page = NULL; |
4641 | swp_entry_t ent = pte_to_swp_entry(ptent); |
4642 | |
4643 | if (!move_anon() || non_swap_entry(ent)) |
4644 | return NULL; |
4645 | usage_count = mem_cgroup_count_swap_user(ent, &page); |
4646 | if (usage_count > 1) { /* we don't move shared anon */ |
4647 | if (page) |
4648 | put_page(page); |
4649 | return NULL; |
4650 | } |
4651 | if (do_swap_account) |
4652 | entry->val = ent.val; |
4653 | |
4654 | return page; |
4655 | } |
4656 | |
4657 | static struct page *mc_handle_file_pte(struct vm_area_struct *vma, |
4658 | unsigned long addr, pte_t ptent, swp_entry_t *entry) |
4659 | { |
4660 | struct page *page = NULL; |
4661 | struct inode *inode; |
4662 | struct address_space *mapping; |
4663 | pgoff_t pgoff; |
4664 | |
4665 | if (!vma->vm_file) /* anonymous vma */ |
4666 | return NULL; |
4667 | if (!move_file()) |
4668 | return NULL; |
4669 | |
4670 | inode = vma->vm_file->f_path.dentry->d_inode; |
4671 | mapping = vma->vm_file->f_mapping; |
4672 | if (pte_none(ptent)) |
4673 | pgoff = linear_page_index(vma, addr); |
4674 | else /* pte_file(ptent) is true */ |
4675 | pgoff = pte_to_pgoff(ptent); |
4676 | |
4677 | /* page is moved even if it's not RSS of this task(page-faulted). */ |
4678 | if (!mapping_cap_swap_backed(mapping)) { /* normal file */ |
4679 | page = find_get_page(mapping, pgoff); |
4680 | } else { /* shmem/tmpfs file. we should take account of swap too. */ |
4681 | swp_entry_t ent; |
4682 | mem_cgroup_get_shmem_target(inode, pgoff, &page, &ent); |
4683 | if (do_swap_account) |
4684 | entry->val = ent.val; |
4685 | } |
4686 | |
4687 | return page; |
4688 | } |
4689 | |
4690 | static int is_target_pte_for_mc(struct vm_area_struct *vma, |
4691 | unsigned long addr, pte_t ptent, union mc_target *target) |
4692 | { |
4693 | struct page *page = NULL; |
4694 | struct page_cgroup *pc; |
4695 | int ret = 0; |
4696 | swp_entry_t ent = { .val = 0 }; |
4697 | |
4698 | if (pte_present(ptent)) |
4699 | page = mc_handle_present_pte(vma, addr, ptent); |
4700 | else if (is_swap_pte(ptent)) |
4701 | page = mc_handle_swap_pte(vma, addr, ptent, &ent); |
4702 | else if (pte_none(ptent) || pte_file(ptent)) |
4703 | page = mc_handle_file_pte(vma, addr, ptent, &ent); |
4704 | |
4705 | if (!page && !ent.val) |
4706 | return 0; |
4707 | if (page) { |
4708 | pc = lookup_page_cgroup(page); |
4709 | /* |
4710 | * Do only loose check w/o page_cgroup lock. |
4711 | * mem_cgroup_move_account() checks the pc is valid or not under |
4712 | * the lock. |
4713 | */ |
4714 | if (PageCgroupUsed(pc) && pc->mem_cgroup == mc.from) { |
4715 | ret = MC_TARGET_PAGE; |
4716 | if (target) |
4717 | target->page = page; |
4718 | } |
4719 | if (!ret || !target) |
4720 | put_page(page); |
4721 | } |
4722 | /* There is a swap entry and a page doesn't exist or isn't charged */ |
4723 | if (ent.val && !ret && |
4724 | css_id(&mc.from->css) == lookup_swap_cgroup(ent)) { |
4725 | ret = MC_TARGET_SWAP; |
4726 | if (target) |
4727 | target->ent = ent; |
4728 | } |
4729 | return ret; |
4730 | } |
4731 | |
4732 | static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd, |
4733 | unsigned long addr, unsigned long end, |
4734 | struct mm_walk *walk) |
4735 | { |
4736 | struct vm_area_struct *vma = walk->private; |
4737 | pte_t *pte; |
4738 | spinlock_t *ptl; |
4739 | |
4740 | VM_BUG_ON(pmd_trans_huge(*pmd)); |
4741 | pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); |
4742 | for (; addr != end; pte++, addr += PAGE_SIZE) |
4743 | if (is_target_pte_for_mc(vma, addr, *pte, NULL)) |
4744 | mc.precharge++; /* increment precharge temporarily */ |
4745 | pte_unmap_unlock(pte - 1, ptl); |
4746 | cond_resched(); |
4747 | |
4748 | return 0; |
4749 | } |
4750 | |
4751 | static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm) |
4752 | { |
4753 | unsigned long precharge; |
4754 | struct vm_area_struct *vma; |
4755 | |
4756 | down_read(&mm->mmap_sem); |
4757 | for (vma = mm->mmap; vma; vma = vma->vm_next) { |
4758 | struct mm_walk mem_cgroup_count_precharge_walk = { |
4759 | .pmd_entry = mem_cgroup_count_precharge_pte_range, |
4760 | .mm = mm, |
4761 | .private = vma, |
4762 | }; |
4763 | if (is_vm_hugetlb_page(vma)) |
4764 | continue; |
4765 | walk_page_range(vma->vm_start, vma->vm_end, |
4766 | &mem_cgroup_count_precharge_walk); |
4767 | } |
4768 | up_read(&mm->mmap_sem); |
4769 | |
4770 | precharge = mc.precharge; |
4771 | mc.precharge = 0; |
4772 | |
4773 | return precharge; |
4774 | } |
4775 | |
4776 | static int mem_cgroup_precharge_mc(struct mm_struct *mm) |
4777 | { |
4778 | unsigned long precharge = mem_cgroup_count_precharge(mm); |
4779 | |
4780 | VM_BUG_ON(mc.moving_task); |
4781 | mc.moving_task = current; |
4782 | return mem_cgroup_do_precharge(precharge); |
4783 | } |
4784 | |
4785 | /* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */ |
4786 | static void __mem_cgroup_clear_mc(void) |
4787 | { |
4788 | struct mem_cgroup *from = mc.from; |
4789 | struct mem_cgroup *to = mc.to; |
4790 | |
4791 | /* we must uncharge all the leftover precharges from mc.to */ |
4792 | if (mc.precharge) { |
4793 | __mem_cgroup_cancel_charge(mc.to, mc.precharge); |
4794 | mc.precharge = 0; |
4795 | } |
4796 | /* |
4797 | * we didn't uncharge from mc.from at mem_cgroup_move_account(), so |
4798 | * we must uncharge here. |
4799 | */ |
4800 | if (mc.moved_charge) { |
4801 | __mem_cgroup_cancel_charge(mc.from, mc.moved_charge); |
4802 | mc.moved_charge = 0; |
4803 | } |
4804 | /* we must fixup refcnts and charges */ |
4805 | if (mc.moved_swap) { |
4806 | /* uncharge swap account from the old cgroup */ |
4807 | if (!mem_cgroup_is_root(mc.from)) |
4808 | res_counter_uncharge(&mc.from->memsw, |
4809 | PAGE_SIZE * mc.moved_swap); |
4810 | __mem_cgroup_put(mc.from, mc.moved_swap); |
4811 | |
4812 | if (!mem_cgroup_is_root(mc.to)) { |
4813 | /* |
4814 | * we charged both to->res and to->memsw, so we should |
4815 | * uncharge to->res. |
4816 | */ |
4817 | res_counter_uncharge(&mc.to->res, |
4818 | PAGE_SIZE * mc.moved_swap); |
4819 | } |
4820 | /* we've already done mem_cgroup_get(mc.to) */ |
4821 | mc.moved_swap = 0; |
4822 | } |
4823 | memcg_oom_recover(from); |
4824 | memcg_oom_recover(to); |
4825 | wake_up_all(&mc.waitq); |
4826 | } |
4827 | |
4828 | static void mem_cgroup_clear_mc(void) |
4829 | { |
4830 | struct mem_cgroup *from = mc.from; |
4831 | |
4832 | /* |
4833 | * we must clear moving_task before waking up waiters at the end of |
4834 | * task migration. |
4835 | */ |
4836 | mc.moving_task = NULL; |
4837 | __mem_cgroup_clear_mc(); |
4838 | spin_lock(&mc.lock); |
4839 | mc.from = NULL; |
4840 | mc.to = NULL; |
4841 | spin_unlock(&mc.lock); |
4842 | mem_cgroup_end_move(from); |
4843 | } |
4844 | |
4845 | static int mem_cgroup_can_attach(struct cgroup_subsys *ss, |
4846 | struct cgroup *cgroup, |
4847 | struct task_struct *p, |
4848 | bool threadgroup) |
4849 | { |
4850 | int ret = 0; |
4851 | struct mem_cgroup *mem = mem_cgroup_from_cont(cgroup); |
4852 | |
4853 | if (mem->move_charge_at_immigrate) { |
4854 | struct mm_struct *mm; |
4855 | struct mem_cgroup *from = mem_cgroup_from_task(p); |
4856 | |
4857 | VM_BUG_ON(from == mem); |
4858 | |
4859 | mm = get_task_mm(p); |
4860 | if (!mm) |
4861 | return 0; |
4862 | /* We move charges only when we move a owner of the mm */ |
4863 | if (mm->owner == p) { |
4864 | VM_BUG_ON(mc.from); |
4865 | VM_BUG_ON(mc.to); |
4866 | VM_BUG_ON(mc.precharge); |
4867 | VM_BUG_ON(mc.moved_charge); |
4868 | VM_BUG_ON(mc.moved_swap); |
4869 | mem_cgroup_start_move(from); |
4870 | spin_lock(&mc.lock); |
4871 | mc.from = from; |
4872 | mc.to = mem; |
4873 | spin_unlock(&mc.lock); |
4874 | /* We set mc.moving_task later */ |
4875 | |
4876 | ret = mem_cgroup_precharge_mc(mm); |
4877 | if (ret) |
4878 | mem_cgroup_clear_mc(); |
4879 | } |
4880 | mmput(mm); |
4881 | } |
4882 | return ret; |
4883 | } |
4884 | |
4885 | static void mem_cgroup_cancel_attach(struct cgroup_subsys *ss, |
4886 | struct cgroup *cgroup, |
4887 | struct task_struct *p, |
4888 | bool threadgroup) |
4889 | { |
4890 | mem_cgroup_clear_mc(); |
4891 | } |
4892 | |
4893 | static int mem_cgroup_move_charge_pte_range(pmd_t *pmd, |
4894 | unsigned long addr, unsigned long end, |
4895 | struct mm_walk *walk) |
4896 | { |
4897 | int ret = 0; |
4898 | struct vm_area_struct *vma = walk->private; |
4899 | pte_t *pte; |
4900 | spinlock_t *ptl; |
4901 | |
4902 | retry: |
4903 | VM_BUG_ON(pmd_trans_huge(*pmd)); |
4904 | pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); |
4905 | for (; addr != end; addr += PAGE_SIZE) { |
4906 | pte_t ptent = *(pte++); |
4907 | union mc_target target; |
4908 | int type; |
4909 | struct page *page; |
4910 | struct page_cgroup *pc; |
4911 | swp_entry_t ent; |
4912 | |
4913 | if (!mc.precharge) |
4914 | break; |
4915 | |
4916 | type = is_target_pte_for_mc(vma, addr, ptent, &target); |
4917 | switch (type) { |
4918 | case MC_TARGET_PAGE: |
4919 | page = target.page; |
4920 | if (isolate_lru_page(page)) |
4921 | goto put; |
4922 | pc = lookup_page_cgroup(page); |
4923 | if (!mem_cgroup_move_account(pc, |
4924 | mc.from, mc.to, false, PAGE_SIZE)) { |
4925 | mc.precharge--; |
4926 | /* we uncharge from mc.from later. */ |
4927 | mc.moved_charge++; |
4928 | } |
4929 | putback_lru_page(page); |
4930 | put: /* is_target_pte_for_mc() gets the page */ |
4931 | put_page(page); |
4932 | break; |
4933 | case MC_TARGET_SWAP: |
4934 | ent = target.ent; |
4935 | if (!mem_cgroup_move_swap_account(ent, |
4936 | mc.from, mc.to, false)) { |
4937 | mc.precharge--; |
4938 | /* we fixup refcnts and charges later. */ |
4939 | mc.moved_swap++; |
4940 | } |
4941 | break; |
4942 | default: |
4943 | break; |
4944 | } |
4945 | } |
4946 | pte_unmap_unlock(pte - 1, ptl); |
4947 | cond_resched(); |
4948 | |
4949 | if (addr != end) { |
4950 | /* |
4951 | * We have consumed all precharges we got in can_attach(). |
4952 | * We try charge one by one, but don't do any additional |
4953 | * charges to mc.to if we have failed in charge once in attach() |
4954 | * phase. |
4955 | */ |
4956 | ret = mem_cgroup_do_precharge(1); |
4957 | if (!ret) |
4958 | goto retry; |
4959 | } |
4960 | |
4961 | return ret; |
4962 | } |
4963 | |
4964 | static void mem_cgroup_move_charge(struct mm_struct *mm) |
4965 | { |
4966 | struct vm_area_struct *vma; |
4967 | |
4968 | lru_add_drain_all(); |
4969 | retry: |
4970 | if (unlikely(!down_read_trylock(&mm->mmap_sem))) { |
4971 | /* |
4972 | * Someone who are holding the mmap_sem might be waiting in |
4973 | * waitq. So we cancel all extra charges, wake up all waiters, |
4974 | * and retry. Because we cancel precharges, we might not be able |
4975 | * to move enough charges, but moving charge is a best-effort |
4976 | * feature anyway, so it wouldn't be a big problem. |
4977 | */ |
4978 | __mem_cgroup_clear_mc(); |
4979 | cond_resched(); |
4980 | goto retry; |
4981 | } |
4982 | for (vma = mm->mmap; vma; vma = vma->vm_next) { |
4983 | int ret; |
4984 | struct mm_walk mem_cgroup_move_charge_walk = { |
4985 | .pmd_entry = mem_cgroup_move_charge_pte_range, |
4986 | .mm = mm, |
4987 | .private = vma, |
4988 | }; |
4989 | if (is_vm_hugetlb_page(vma)) |
4990 | continue; |
4991 | ret = walk_page_range(vma->vm_start, vma->vm_end, |
4992 | &mem_cgroup_move_charge_walk); |
4993 | if (ret) |
4994 | /* |
4995 | * means we have consumed all precharges and failed in |
4996 | * doing additional charge. Just abandon here. |
4997 | */ |
4998 | break; |
4999 | } |
5000 | up_read(&mm->mmap_sem); |
5001 | } |
5002 | |
5003 | static void mem_cgroup_move_task(struct cgroup_subsys *ss, |
5004 | struct cgroup *cont, |
5005 | struct cgroup *old_cont, |
5006 | struct task_struct *p, |
5007 | bool threadgroup) |
5008 | { |
5009 | struct mm_struct *mm; |
5010 | |
5011 | if (!mc.to) |
5012 | /* no need to move charge */ |
5013 | return; |
5014 | |
5015 | mm = get_task_mm(p); |
5016 | if (mm) { |
5017 | mem_cgroup_move_charge(mm); |
5018 | mmput(mm); |
5019 | } |
5020 | mem_cgroup_clear_mc(); |
5021 | } |
5022 | #else /* !CONFIG_MMU */ |
5023 | static int mem_cgroup_can_attach(struct cgroup_subsys *ss, |
5024 | struct cgroup *cgroup, |
5025 | struct task_struct *p, |
5026 | bool threadgroup) |
5027 | { |
5028 | return 0; |
5029 | } |
5030 | static void mem_cgroup_cancel_attach(struct cgroup_subsys *ss, |
5031 | struct cgroup *cgroup, |
5032 | struct task_struct *p, |
5033 | bool threadgroup) |
5034 | { |
5035 | } |
5036 | static void mem_cgroup_move_task(struct cgroup_subsys *ss, |
5037 | struct cgroup *cont, |
5038 | struct cgroup *old_cont, |
5039 | struct task_struct *p, |
5040 | bool threadgroup) |
5041 | { |
5042 | } |
5043 | #endif |
5044 | |
5045 | struct cgroup_subsys mem_cgroup_subsys = { |
5046 | .name = "memory", |
5047 | .subsys_id = mem_cgroup_subsys_id, |
5048 | .create = mem_cgroup_create, |
5049 | .pre_destroy = mem_cgroup_pre_destroy, |
5050 | .destroy = mem_cgroup_destroy, |
5051 | .populate = mem_cgroup_populate, |
5052 | .can_attach = mem_cgroup_can_attach, |
5053 | .cancel_attach = mem_cgroup_cancel_attach, |
5054 | .attach = mem_cgroup_move_task, |
5055 | .early_init = 0, |
5056 | .use_id = 1, |
5057 | }; |
5058 | |
5059 | #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP |
5060 | static int __init enable_swap_account(char *s) |
5061 | { |
5062 | /* consider enabled if no parameter or 1 is given */ |
5063 | if (!(*s) || !strcmp(s, "=1")) |
5064 | really_do_swap_account = 1; |
5065 | else if (!strcmp(s, "=0")) |
5066 | really_do_swap_account = 0; |
5067 | return 1; |
5068 | } |
5069 | __setup("swapaccount", enable_swap_account); |
5070 | |
5071 | static int __init disable_swap_account(char *s) |
5072 | { |
5073 | printk_once("noswapaccount is deprecated and will be removed in 2.6.40. Use swapaccount=0 instead\n"); |
5074 | enable_swap_account("=0"); |
5075 | return 1; |
5076 | } |
5077 | __setup("noswapaccount", disable_swap_account); |
5078 | #endif |
5079 |
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