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8cdea7c0 BS |
1 | /* memcontrol.c - Memory Controller |
2 | * | |
3 | * Copyright IBM Corporation, 2007 | |
4 | * Author Balbir Singh <balbir@linux.vnet.ibm.com> | |
5 | * | |
78fb7466 PE |
6 | * Copyright 2007 OpenVZ SWsoft Inc |
7 | * Author: Pavel Emelianov <xemul@openvz.org> | |
8 | * | |
8cdea7c0 BS |
9 | * This program is free software; you can redistribute it and/or modify |
10 | * it under the terms of the GNU General Public License as published by | |
11 | * the Free Software Foundation; either version 2 of the License, or | |
12 | * (at your option) any later version. | |
13 | * | |
14 | * This program is distributed in the hope that it will be useful, | |
15 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
17 | * GNU General Public License for more details. | |
18 | */ | |
19 | ||
20 | #include <linux/res_counter.h> | |
21 | #include <linux/memcontrol.h> | |
22 | #include <linux/cgroup.h> | |
78fb7466 | 23 | #include <linux/mm.h> |
8a9f3ccd | 24 | #include <linux/page-flags.h> |
66e1707b | 25 | #include <linux/backing-dev.h> |
8a9f3ccd BS |
26 | #include <linux/bit_spinlock.h> |
27 | #include <linux/rcupdate.h> | |
66e1707b BS |
28 | #include <linux/swap.h> |
29 | #include <linux/spinlock.h> | |
30 | #include <linux/fs.h> | |
8cdea7c0 | 31 | |
8697d331 BS |
32 | #include <asm/uaccess.h> |
33 | ||
8cdea7c0 | 34 | struct cgroup_subsys mem_cgroup_subsys; |
66e1707b | 35 | static const int MEM_CGROUP_RECLAIM_RETRIES = 5; |
8cdea7c0 BS |
36 | |
37 | /* | |
38 | * The memory controller data structure. The memory controller controls both | |
39 | * page cache and RSS per cgroup. We would eventually like to provide | |
40 | * statistics based on the statistics developed by Rik Van Riel for clock-pro, | |
41 | * to help the administrator determine what knobs to tune. | |
42 | * | |
43 | * TODO: Add a water mark for the memory controller. Reclaim will begin when | |
8a9f3ccd BS |
44 | * we hit the water mark. May be even add a low water mark, such that |
45 | * no reclaim occurs from a cgroup at it's low water mark, this is | |
46 | * a feature that will be implemented much later in the future. | |
8cdea7c0 BS |
47 | */ |
48 | struct mem_cgroup { | |
49 | struct cgroup_subsys_state css; | |
50 | /* | |
51 | * the counter to account for memory usage | |
52 | */ | |
53 | struct res_counter res; | |
78fb7466 PE |
54 | /* |
55 | * Per cgroup active and inactive list, similar to the | |
56 | * per zone LRU lists. | |
57 | * TODO: Consider making these lists per zone | |
58 | */ | |
59 | struct list_head active_list; | |
60 | struct list_head inactive_list; | |
66e1707b BS |
61 | /* |
62 | * spin_lock to protect the per cgroup LRU | |
63 | */ | |
64 | spinlock_t lru_lock; | |
8697d331 | 65 | unsigned long control_type; /* control RSS or RSS+Pagecache */ |
8cdea7c0 BS |
66 | }; |
67 | ||
8a9f3ccd BS |
68 | /* |
69 | * We use the lower bit of the page->page_cgroup pointer as a bit spin | |
70 | * lock. We need to ensure that page->page_cgroup is atleast two | |
71 | * byte aligned (based on comments from Nick Piggin) | |
72 | */ | |
73 | #define PAGE_CGROUP_LOCK_BIT 0x0 | |
74 | #define PAGE_CGROUP_LOCK (1 << PAGE_CGROUP_LOCK_BIT) | |
75 | ||
8cdea7c0 BS |
76 | /* |
77 | * A page_cgroup page is associated with every page descriptor. The | |
78 | * page_cgroup helps us identify information about the cgroup | |
79 | */ | |
80 | struct page_cgroup { | |
81 | struct list_head lru; /* per cgroup LRU list */ | |
82 | struct page *page; | |
83 | struct mem_cgroup *mem_cgroup; | |
8a9f3ccd BS |
84 | atomic_t ref_cnt; /* Helpful when pages move b/w */ |
85 | /* mapped and cached states */ | |
8cdea7c0 BS |
86 | }; |
87 | ||
8697d331 BS |
88 | enum { |
89 | MEM_CGROUP_TYPE_UNSPEC = 0, | |
90 | MEM_CGROUP_TYPE_MAPPED, | |
91 | MEM_CGROUP_TYPE_CACHED, | |
92 | MEM_CGROUP_TYPE_ALL, | |
93 | MEM_CGROUP_TYPE_MAX, | |
94 | }; | |
95 | ||
96 | static struct mem_cgroup init_mem_cgroup; | |
8cdea7c0 BS |
97 | |
98 | static inline | |
99 | struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont) | |
100 | { | |
101 | return container_of(cgroup_subsys_state(cont, | |
102 | mem_cgroup_subsys_id), struct mem_cgroup, | |
103 | css); | |
104 | } | |
105 | ||
78fb7466 PE |
106 | static inline |
107 | struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p) | |
108 | { | |
109 | return container_of(task_subsys_state(p, mem_cgroup_subsys_id), | |
110 | struct mem_cgroup, css); | |
111 | } | |
112 | ||
bed7161a BS |
113 | inline struct mem_cgroup *mm_cgroup(struct mm_struct *mm) |
114 | { | |
115 | return rcu_dereference(mm->mem_cgroup); | |
116 | } | |
117 | ||
78fb7466 PE |
118 | void mm_init_cgroup(struct mm_struct *mm, struct task_struct *p) |
119 | { | |
120 | struct mem_cgroup *mem; | |
121 | ||
122 | mem = mem_cgroup_from_task(p); | |
123 | css_get(&mem->css); | |
124 | mm->mem_cgroup = mem; | |
125 | } | |
126 | ||
127 | void mm_free_cgroup(struct mm_struct *mm) | |
128 | { | |
129 | css_put(&mm->mem_cgroup->css); | |
130 | } | |
131 | ||
8a9f3ccd BS |
132 | static inline int page_cgroup_locked(struct page *page) |
133 | { | |
134 | return bit_spin_is_locked(PAGE_CGROUP_LOCK_BIT, | |
135 | &page->page_cgroup); | |
136 | } | |
137 | ||
78fb7466 PE |
138 | void page_assign_page_cgroup(struct page *page, struct page_cgroup *pc) |
139 | { | |
8a9f3ccd BS |
140 | int locked; |
141 | ||
142 | /* | |
143 | * While resetting the page_cgroup we might not hold the | |
144 | * page_cgroup lock. free_hot_cold_page() is an example | |
145 | * of such a scenario | |
146 | */ | |
147 | if (pc) | |
148 | VM_BUG_ON(!page_cgroup_locked(page)); | |
149 | locked = (page->page_cgroup & PAGE_CGROUP_LOCK); | |
150 | page->page_cgroup = ((unsigned long)pc | locked); | |
78fb7466 PE |
151 | } |
152 | ||
153 | struct page_cgroup *page_get_page_cgroup(struct page *page) | |
154 | { | |
8a9f3ccd BS |
155 | return (struct page_cgroup *) |
156 | (page->page_cgroup & ~PAGE_CGROUP_LOCK); | |
157 | } | |
158 | ||
8697d331 | 159 | static void __always_inline lock_page_cgroup(struct page *page) |
8a9f3ccd BS |
160 | { |
161 | bit_spin_lock(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup); | |
162 | VM_BUG_ON(!page_cgroup_locked(page)); | |
163 | } | |
164 | ||
8697d331 | 165 | static void __always_inline unlock_page_cgroup(struct page *page) |
8a9f3ccd BS |
166 | { |
167 | bit_spin_unlock(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup); | |
168 | } | |
169 | ||
8697d331 | 170 | static void __mem_cgroup_move_lists(struct page_cgroup *pc, bool active) |
66e1707b BS |
171 | { |
172 | if (active) | |
173 | list_move(&pc->lru, &pc->mem_cgroup->active_list); | |
174 | else | |
175 | list_move(&pc->lru, &pc->mem_cgroup->inactive_list); | |
176 | } | |
177 | ||
178 | /* | |
179 | * This routine assumes that the appropriate zone's lru lock is already held | |
180 | */ | |
181 | void mem_cgroup_move_lists(struct page_cgroup *pc, bool active) | |
182 | { | |
183 | struct mem_cgroup *mem; | |
184 | if (!pc) | |
185 | return; | |
186 | ||
187 | mem = pc->mem_cgroup; | |
188 | ||
189 | spin_lock(&mem->lru_lock); | |
190 | __mem_cgroup_move_lists(pc, active); | |
191 | spin_unlock(&mem->lru_lock); | |
192 | } | |
193 | ||
194 | unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan, | |
195 | struct list_head *dst, | |
196 | unsigned long *scanned, int order, | |
197 | int mode, struct zone *z, | |
198 | struct mem_cgroup *mem_cont, | |
199 | int active) | |
200 | { | |
201 | unsigned long nr_taken = 0; | |
202 | struct page *page; | |
203 | unsigned long scan; | |
204 | LIST_HEAD(pc_list); | |
205 | struct list_head *src; | |
206 | struct page_cgroup *pc; | |
207 | ||
208 | if (active) | |
209 | src = &mem_cont->active_list; | |
210 | else | |
211 | src = &mem_cont->inactive_list; | |
212 | ||
213 | spin_lock(&mem_cont->lru_lock); | |
214 | for (scan = 0; scan < nr_to_scan && !list_empty(src); scan++) { | |
215 | pc = list_entry(src->prev, struct page_cgroup, lru); | |
216 | page = pc->page; | |
217 | VM_BUG_ON(!pc); | |
218 | ||
219 | if (PageActive(page) && !active) { | |
220 | __mem_cgroup_move_lists(pc, true); | |
221 | scan--; | |
222 | continue; | |
223 | } | |
224 | if (!PageActive(page) && active) { | |
225 | __mem_cgroup_move_lists(pc, false); | |
226 | scan--; | |
227 | continue; | |
228 | } | |
229 | ||
230 | /* | |
231 | * Reclaim, per zone | |
232 | * TODO: make the active/inactive lists per zone | |
233 | */ | |
234 | if (page_zone(page) != z) | |
235 | continue; | |
236 | ||
237 | /* | |
238 | * Check if the meta page went away from under us | |
239 | */ | |
240 | if (!list_empty(&pc->lru)) | |
241 | list_move(&pc->lru, &pc_list); | |
242 | else | |
243 | continue; | |
244 | ||
245 | if (__isolate_lru_page(page, mode) == 0) { | |
246 | list_move(&page->lru, dst); | |
247 | nr_taken++; | |
248 | } | |
249 | } | |
250 | ||
251 | list_splice(&pc_list, src); | |
252 | spin_unlock(&mem_cont->lru_lock); | |
253 | ||
254 | *scanned = scan; | |
255 | return nr_taken; | |
256 | } | |
257 | ||
8a9f3ccd BS |
258 | /* |
259 | * Charge the memory controller for page usage. | |
260 | * Return | |
261 | * 0 if the charge was successful | |
262 | * < 0 if the cgroup is over its limit | |
263 | */ | |
264 | int mem_cgroup_charge(struct page *page, struct mm_struct *mm) | |
265 | { | |
266 | struct mem_cgroup *mem; | |
267 | struct page_cgroup *pc, *race_pc; | |
66e1707b BS |
268 | unsigned long flags; |
269 | unsigned long nr_retries = MEM_CGROUP_RECLAIM_RETRIES; | |
8a9f3ccd BS |
270 | |
271 | /* | |
272 | * Should page_cgroup's go to their own slab? | |
273 | * One could optimize the performance of the charging routine | |
274 | * by saving a bit in the page_flags and using it as a lock | |
275 | * to see if the cgroup page already has a page_cgroup associated | |
276 | * with it | |
277 | */ | |
66e1707b | 278 | retry: |
8a9f3ccd BS |
279 | lock_page_cgroup(page); |
280 | pc = page_get_page_cgroup(page); | |
281 | /* | |
282 | * The page_cgroup exists and the page has already been accounted | |
283 | */ | |
284 | if (pc) { | |
66e1707b BS |
285 | if (unlikely(!atomic_inc_not_zero(&pc->ref_cnt))) { |
286 | /* this page is under being uncharged ? */ | |
287 | unlock_page_cgroup(page); | |
288 | cpu_relax(); | |
289 | goto retry; | |
290 | } else | |
291 | goto done; | |
8a9f3ccd BS |
292 | } |
293 | ||
294 | unlock_page_cgroup(page); | |
295 | ||
296 | pc = kzalloc(sizeof(struct page_cgroup), GFP_KERNEL); | |
297 | if (pc == NULL) | |
298 | goto err; | |
299 | ||
300 | rcu_read_lock(); | |
301 | /* | |
302 | * We always charge the cgroup the mm_struct belongs to | |
303 | * the mm_struct's mem_cgroup changes on task migration if the | |
304 | * thread group leader migrates. It's possible that mm is not | |
305 | * set, if so charge the init_mm (happens for pagecache usage). | |
306 | */ | |
307 | if (!mm) | |
308 | mm = &init_mm; | |
309 | ||
310 | mem = rcu_dereference(mm->mem_cgroup); | |
311 | /* | |
312 | * For every charge from the cgroup, increment reference | |
313 | * count | |
314 | */ | |
315 | css_get(&mem->css); | |
316 | rcu_read_unlock(); | |
317 | ||
318 | /* | |
319 | * If we created the page_cgroup, we should free it on exceeding | |
320 | * the cgroup limit. | |
321 | */ | |
0eea1030 | 322 | while (res_counter_charge(&mem->res, PAGE_SIZE)) { |
66e1707b BS |
323 | if (try_to_free_mem_cgroup_pages(mem)) |
324 | continue; | |
325 | ||
326 | /* | |
327 | * try_to_free_mem_cgroup_pages() might not give us a full | |
328 | * picture of reclaim. Some pages are reclaimed and might be | |
329 | * moved to swap cache or just unmapped from the cgroup. | |
330 | * Check the limit again to see if the reclaim reduced the | |
331 | * current usage of the cgroup before giving up | |
332 | */ | |
333 | if (res_counter_check_under_limit(&mem->res)) | |
334 | continue; | |
335 | /* | |
336 | * Since we control both RSS and cache, we end up with a | |
337 | * very interesting scenario where we end up reclaiming | |
338 | * memory (essentially RSS), since the memory is pushed | |
339 | * to swap cache, we eventually end up adding those | |
340 | * pages back to our list. Hence we give ourselves a | |
341 | * few chances before we fail | |
342 | */ | |
343 | else if (nr_retries--) { | |
344 | congestion_wait(WRITE, HZ/10); | |
345 | continue; | |
346 | } | |
347 | ||
8a9f3ccd | 348 | css_put(&mem->css); |
c7ba5c9e | 349 | mem_cgroup_out_of_memory(mem, GFP_KERNEL); |
8a9f3ccd BS |
350 | goto free_pc; |
351 | } | |
352 | ||
353 | lock_page_cgroup(page); | |
354 | /* | |
355 | * Check if somebody else beat us to allocating the page_cgroup | |
356 | */ | |
357 | race_pc = page_get_page_cgroup(page); | |
358 | if (race_pc) { | |
359 | kfree(pc); | |
360 | pc = race_pc; | |
361 | atomic_inc(&pc->ref_cnt); | |
0eea1030 | 362 | res_counter_uncharge(&mem->res, PAGE_SIZE); |
8a9f3ccd BS |
363 | css_put(&mem->css); |
364 | goto done; | |
365 | } | |
366 | ||
367 | atomic_set(&pc->ref_cnt, 1); | |
368 | pc->mem_cgroup = mem; | |
369 | pc->page = page; | |
370 | page_assign_page_cgroup(page, pc); | |
371 | ||
66e1707b BS |
372 | spin_lock_irqsave(&mem->lru_lock, flags); |
373 | list_add(&pc->lru, &mem->active_list); | |
374 | spin_unlock_irqrestore(&mem->lru_lock, flags); | |
375 | ||
8a9f3ccd BS |
376 | done: |
377 | unlock_page_cgroup(page); | |
378 | return 0; | |
379 | free_pc: | |
380 | kfree(pc); | |
8a9f3ccd | 381 | err: |
8a9f3ccd BS |
382 | return -ENOMEM; |
383 | } | |
384 | ||
8697d331 BS |
385 | /* |
386 | * See if the cached pages should be charged at all? | |
387 | */ | |
388 | int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm) | |
389 | { | |
390 | struct mem_cgroup *mem; | |
391 | if (!mm) | |
392 | mm = &init_mm; | |
393 | ||
394 | mem = rcu_dereference(mm->mem_cgroup); | |
395 | if (mem->control_type == MEM_CGROUP_TYPE_ALL) | |
396 | return mem_cgroup_charge(page, mm); | |
397 | else | |
398 | return 0; | |
399 | } | |
400 | ||
8a9f3ccd BS |
401 | /* |
402 | * Uncharging is always a welcome operation, we never complain, simply | |
403 | * uncharge. | |
404 | */ | |
405 | void mem_cgroup_uncharge(struct page_cgroup *pc) | |
406 | { | |
407 | struct mem_cgroup *mem; | |
408 | struct page *page; | |
66e1707b | 409 | unsigned long flags; |
8a9f3ccd | 410 | |
8697d331 BS |
411 | /* |
412 | * This can handle cases when a page is not charged at all and we | |
413 | * are switching between handling the control_type. | |
414 | */ | |
8a9f3ccd BS |
415 | if (!pc) |
416 | return; | |
417 | ||
418 | if (atomic_dec_and_test(&pc->ref_cnt)) { | |
419 | page = pc->page; | |
420 | lock_page_cgroup(page); | |
421 | mem = pc->mem_cgroup; | |
422 | css_put(&mem->css); | |
423 | page_assign_page_cgroup(page, NULL); | |
424 | unlock_page_cgroup(page); | |
0eea1030 | 425 | res_counter_uncharge(&mem->res, PAGE_SIZE); |
66e1707b BS |
426 | |
427 | spin_lock_irqsave(&mem->lru_lock, flags); | |
428 | list_del_init(&pc->lru); | |
429 | spin_unlock_irqrestore(&mem->lru_lock, flags); | |
8a9f3ccd BS |
430 | kfree(pc); |
431 | } | |
78fb7466 PE |
432 | } |
433 | ||
0eea1030 BS |
434 | int mem_cgroup_write_strategy(char *buf, unsigned long long *tmp) |
435 | { | |
436 | *tmp = memparse(buf, &buf); | |
437 | if (*buf != '\0') | |
438 | return -EINVAL; | |
439 | ||
440 | /* | |
441 | * Round up the value to the closest page size | |
442 | */ | |
443 | *tmp = ((*tmp + PAGE_SIZE - 1) >> PAGE_SHIFT) << PAGE_SHIFT; | |
444 | return 0; | |
445 | } | |
446 | ||
447 | static ssize_t mem_cgroup_read(struct cgroup *cont, | |
448 | struct cftype *cft, struct file *file, | |
449 | char __user *userbuf, size_t nbytes, loff_t *ppos) | |
8cdea7c0 BS |
450 | { |
451 | return res_counter_read(&mem_cgroup_from_cont(cont)->res, | |
0eea1030 BS |
452 | cft->private, userbuf, nbytes, ppos, |
453 | NULL); | |
8cdea7c0 BS |
454 | } |
455 | ||
456 | static ssize_t mem_cgroup_write(struct cgroup *cont, struct cftype *cft, | |
457 | struct file *file, const char __user *userbuf, | |
458 | size_t nbytes, loff_t *ppos) | |
459 | { | |
460 | return res_counter_write(&mem_cgroup_from_cont(cont)->res, | |
0eea1030 BS |
461 | cft->private, userbuf, nbytes, ppos, |
462 | mem_cgroup_write_strategy); | |
8cdea7c0 BS |
463 | } |
464 | ||
8697d331 BS |
465 | static ssize_t mem_control_type_write(struct cgroup *cont, |
466 | struct cftype *cft, struct file *file, | |
467 | const char __user *userbuf, | |
468 | size_t nbytes, loff_t *pos) | |
469 | { | |
470 | int ret; | |
471 | char *buf, *end; | |
472 | unsigned long tmp; | |
473 | struct mem_cgroup *mem; | |
474 | ||
475 | mem = mem_cgroup_from_cont(cont); | |
476 | buf = kmalloc(nbytes + 1, GFP_KERNEL); | |
477 | ret = -ENOMEM; | |
478 | if (buf == NULL) | |
479 | goto out; | |
480 | ||
481 | buf[nbytes] = 0; | |
482 | ret = -EFAULT; | |
483 | if (copy_from_user(buf, userbuf, nbytes)) | |
484 | goto out_free; | |
485 | ||
486 | ret = -EINVAL; | |
487 | tmp = simple_strtoul(buf, &end, 10); | |
488 | if (*end != '\0') | |
489 | goto out_free; | |
490 | ||
491 | if (tmp <= MEM_CGROUP_TYPE_UNSPEC || tmp >= MEM_CGROUP_TYPE_MAX) | |
492 | goto out_free; | |
493 | ||
494 | mem->control_type = tmp; | |
495 | ret = nbytes; | |
496 | out_free: | |
497 | kfree(buf); | |
498 | out: | |
499 | return ret; | |
500 | } | |
501 | ||
502 | static ssize_t mem_control_type_read(struct cgroup *cont, | |
503 | struct cftype *cft, | |
504 | struct file *file, char __user *userbuf, | |
505 | size_t nbytes, loff_t *ppos) | |
506 | { | |
507 | unsigned long val; | |
508 | char buf[64], *s; | |
509 | struct mem_cgroup *mem; | |
510 | ||
511 | mem = mem_cgroup_from_cont(cont); | |
512 | s = buf; | |
513 | val = mem->control_type; | |
514 | s += sprintf(s, "%lu\n", val); | |
515 | return simple_read_from_buffer((void __user *)userbuf, nbytes, | |
516 | ppos, buf, s - buf); | |
517 | } | |
518 | ||
8cdea7c0 BS |
519 | static struct cftype mem_cgroup_files[] = { |
520 | { | |
0eea1030 | 521 | .name = "usage_in_bytes", |
8cdea7c0 BS |
522 | .private = RES_USAGE, |
523 | .read = mem_cgroup_read, | |
524 | }, | |
525 | { | |
0eea1030 | 526 | .name = "limit_in_bytes", |
8cdea7c0 BS |
527 | .private = RES_LIMIT, |
528 | .write = mem_cgroup_write, | |
529 | .read = mem_cgroup_read, | |
530 | }, | |
531 | { | |
532 | .name = "failcnt", | |
533 | .private = RES_FAILCNT, | |
534 | .read = mem_cgroup_read, | |
535 | }, | |
8697d331 BS |
536 | { |
537 | .name = "control_type", | |
538 | .write = mem_control_type_write, | |
539 | .read = mem_control_type_read, | |
540 | }, | |
8cdea7c0 BS |
541 | }; |
542 | ||
78fb7466 PE |
543 | static struct mem_cgroup init_mem_cgroup; |
544 | ||
8cdea7c0 BS |
545 | static struct cgroup_subsys_state * |
546 | mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont) | |
547 | { | |
548 | struct mem_cgroup *mem; | |
549 | ||
78fb7466 PE |
550 | if (unlikely((cont->parent) == NULL)) { |
551 | mem = &init_mem_cgroup; | |
552 | init_mm.mem_cgroup = mem; | |
553 | } else | |
554 | mem = kzalloc(sizeof(struct mem_cgroup), GFP_KERNEL); | |
555 | ||
556 | if (mem == NULL) | |
557 | return NULL; | |
8cdea7c0 BS |
558 | |
559 | res_counter_init(&mem->res); | |
8a9f3ccd BS |
560 | INIT_LIST_HEAD(&mem->active_list); |
561 | INIT_LIST_HEAD(&mem->inactive_list); | |
66e1707b | 562 | spin_lock_init(&mem->lru_lock); |
8697d331 | 563 | mem->control_type = MEM_CGROUP_TYPE_ALL; |
8cdea7c0 BS |
564 | return &mem->css; |
565 | } | |
566 | ||
567 | static void mem_cgroup_destroy(struct cgroup_subsys *ss, | |
568 | struct cgroup *cont) | |
569 | { | |
570 | kfree(mem_cgroup_from_cont(cont)); | |
571 | } | |
572 | ||
573 | static int mem_cgroup_populate(struct cgroup_subsys *ss, | |
574 | struct cgroup *cont) | |
575 | { | |
576 | return cgroup_add_files(cont, ss, mem_cgroup_files, | |
577 | ARRAY_SIZE(mem_cgroup_files)); | |
578 | } | |
579 | ||
67e465a7 BS |
580 | static void mem_cgroup_move_task(struct cgroup_subsys *ss, |
581 | struct cgroup *cont, | |
582 | struct cgroup *old_cont, | |
583 | struct task_struct *p) | |
584 | { | |
585 | struct mm_struct *mm; | |
586 | struct mem_cgroup *mem, *old_mem; | |
587 | ||
588 | mm = get_task_mm(p); | |
589 | if (mm == NULL) | |
590 | return; | |
591 | ||
592 | mem = mem_cgroup_from_cont(cont); | |
593 | old_mem = mem_cgroup_from_cont(old_cont); | |
594 | ||
595 | if (mem == old_mem) | |
596 | goto out; | |
597 | ||
598 | /* | |
599 | * Only thread group leaders are allowed to migrate, the mm_struct is | |
600 | * in effect owned by the leader | |
601 | */ | |
602 | if (p->tgid != p->pid) | |
603 | goto out; | |
604 | ||
605 | css_get(&mem->css); | |
606 | rcu_assign_pointer(mm->mem_cgroup, mem); | |
607 | css_put(&old_mem->css); | |
608 | ||
609 | out: | |
610 | mmput(mm); | |
611 | return; | |
612 | } | |
613 | ||
8cdea7c0 BS |
614 | struct cgroup_subsys mem_cgroup_subsys = { |
615 | .name = "memory", | |
616 | .subsys_id = mem_cgroup_subsys_id, | |
617 | .create = mem_cgroup_create, | |
618 | .destroy = mem_cgroup_destroy, | |
619 | .populate = mem_cgroup_populate, | |
67e465a7 | 620 | .attach = mem_cgroup_move_task, |
78fb7466 | 621 | .early_init = 1, |
8cdea7c0 | 622 | }; |