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