Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/mm/swap.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds | |
5 | */ | |
6 | ||
7 | /* | |
183ff22b | 8 | * This file contains the default values for the operation of the |
1da177e4 LT |
9 | * Linux VM subsystem. Fine-tuning documentation can be found in |
10 | * Documentation/sysctl/vm.txt. | |
11 | * Started 18.12.91 | |
12 | * Swap aging added 23.2.95, Stephen Tweedie. | |
13 | * Buffermem limits added 12.3.98, Rik van Riel. | |
14 | */ | |
15 | ||
16 | #include <linux/mm.h> | |
17 | #include <linux/sched.h> | |
18 | #include <linux/kernel_stat.h> | |
19 | #include <linux/swap.h> | |
20 | #include <linux/mman.h> | |
21 | #include <linux/pagemap.h> | |
22 | #include <linux/pagevec.h> | |
23 | #include <linux/init.h> | |
b95f1b31 | 24 | #include <linux/export.h> |
1da177e4 | 25 | #include <linux/mm_inline.h> |
1da177e4 LT |
26 | #include <linux/percpu_counter.h> |
27 | #include <linux/percpu.h> | |
28 | #include <linux/cpu.h> | |
29 | #include <linux/notifier.h> | |
e0bf68dd | 30 | #include <linux/backing-dev.h> |
66e1707b | 31 | #include <linux/memcontrol.h> |
5a0e3ad6 | 32 | #include <linux/gfp.h> |
1da177e4 | 33 | |
64d6519d LS |
34 | #include "internal.h" |
35 | ||
1da177e4 LT |
36 | /* How many pages do we try to swap or page in/out together? */ |
37 | int page_cluster; | |
38 | ||
f04e9ebb | 39 | static DEFINE_PER_CPU(struct pagevec[NR_LRU_LISTS], lru_add_pvecs); |
f84f9504 | 40 | static DEFINE_PER_CPU(struct pagevec, lru_rotate_pvecs); |
31560180 | 41 | static DEFINE_PER_CPU(struct pagevec, lru_deactivate_pvecs); |
902aaed0 | 42 | |
b221385b AB |
43 | /* |
44 | * This path almost never happens for VM activity - pages are normally | |
45 | * freed via pagevecs. But it gets used by networking. | |
46 | */ | |
920c7a5d | 47 | static void __page_cache_release(struct page *page) |
b221385b AB |
48 | { |
49 | if (PageLRU(page)) { | |
50 | unsigned long flags; | |
51 | struct zone *zone = page_zone(page); | |
52 | ||
53 | spin_lock_irqsave(&zone->lru_lock, flags); | |
54 | VM_BUG_ON(!PageLRU(page)); | |
55 | __ClearPageLRU(page); | |
56 | del_page_from_lru(zone, page); | |
57 | spin_unlock_irqrestore(&zone->lru_lock, flags); | |
58 | } | |
91807063 AA |
59 | } |
60 | ||
61 | static void __put_single_page(struct page *page) | |
62 | { | |
63 | __page_cache_release(page); | |
fc91668e | 64 | free_hot_cold_page(page, 0); |
b221385b AB |
65 | } |
66 | ||
91807063 | 67 | static void __put_compound_page(struct page *page) |
1da177e4 | 68 | { |
91807063 | 69 | compound_page_dtor *dtor; |
1da177e4 | 70 | |
91807063 AA |
71 | __page_cache_release(page); |
72 | dtor = get_compound_page_dtor(page); | |
73 | (*dtor)(page); | |
74 | } | |
75 | ||
76 | static void put_compound_page(struct page *page) | |
77 | { | |
78 | if (unlikely(PageTail(page))) { | |
79 | /* __split_huge_page_refcount can run under us */ | |
70b50f94 AA |
80 | struct page *page_head = compound_trans_head(page); |
81 | ||
82 | if (likely(page != page_head && | |
83 | get_page_unless_zero(page_head))) { | |
91807063 AA |
84 | unsigned long flags; |
85 | /* | |
70b50f94 AA |
86 | * page_head wasn't a dangling pointer but it |
87 | * may not be a head page anymore by the time | |
88 | * we obtain the lock. That is ok as long as it | |
89 | * can't be freed from under us. | |
91807063 | 90 | */ |
91807063 AA |
91 | flags = compound_lock_irqsave(page_head); |
92 | if (unlikely(!PageTail(page))) { | |
93 | /* __split_huge_page_refcount run before us */ | |
94 | compound_unlock_irqrestore(page_head, flags); | |
95 | VM_BUG_ON(PageHead(page_head)); | |
91807063 AA |
96 | if (put_page_testzero(page_head)) |
97 | __put_single_page(page_head); | |
98 | out_put_single: | |
99 | if (put_page_testzero(page)) | |
100 | __put_single_page(page); | |
101 | return; | |
102 | } | |
103 | VM_BUG_ON(page_head != page->first_page); | |
104 | /* | |
105 | * We can release the refcount taken by | |
70b50f94 AA |
106 | * get_page_unless_zero() now that |
107 | * __split_huge_page_refcount() is blocked on | |
108 | * the compound_lock. | |
91807063 AA |
109 | */ |
110 | if (put_page_testzero(page_head)) | |
111 | VM_BUG_ON(1); | |
112 | /* __split_huge_page_refcount will wait now */ | |
70b50f94 AA |
113 | VM_BUG_ON(page_mapcount(page) <= 0); |
114 | atomic_dec(&page->_mapcount); | |
91807063 | 115 | VM_BUG_ON(atomic_read(&page_head->_count) <= 0); |
70b50f94 | 116 | VM_BUG_ON(atomic_read(&page->_count) != 0); |
91807063 | 117 | compound_unlock_irqrestore(page_head, flags); |
a95a82e9 AA |
118 | if (put_page_testzero(page_head)) { |
119 | if (PageHead(page_head)) | |
120 | __put_compound_page(page_head); | |
121 | else | |
122 | __put_single_page(page_head); | |
123 | } | |
91807063 AA |
124 | } else { |
125 | /* page_head is a dangling pointer */ | |
126 | VM_BUG_ON(PageTail(page)); | |
127 | goto out_put_single; | |
128 | } | |
129 | } else if (put_page_testzero(page)) { | |
130 | if (PageHead(page)) | |
131 | __put_compound_page(page); | |
132 | else | |
133 | __put_single_page(page); | |
1da177e4 | 134 | } |
8519fb30 NP |
135 | } |
136 | ||
137 | void put_page(struct page *page) | |
138 | { | |
139 | if (unlikely(PageCompound(page))) | |
140 | put_compound_page(page); | |
141 | else if (put_page_testzero(page)) | |
91807063 | 142 | __put_single_page(page); |
1da177e4 LT |
143 | } |
144 | EXPORT_SYMBOL(put_page); | |
1da177e4 | 145 | |
70b50f94 AA |
146 | /* |
147 | * This function is exported but must not be called by anything other | |
148 | * than get_page(). It implements the slow path of get_page(). | |
149 | */ | |
150 | bool __get_page_tail(struct page *page) | |
151 | { | |
152 | /* | |
153 | * This takes care of get_page() if run on a tail page | |
154 | * returned by one of the get_user_pages/follow_page variants. | |
155 | * get_user_pages/follow_page itself doesn't need the compound | |
156 | * lock because it runs __get_page_tail_foll() under the | |
157 | * proper PT lock that already serializes against | |
158 | * split_huge_page(). | |
159 | */ | |
160 | unsigned long flags; | |
161 | bool got = false; | |
162 | struct page *page_head = compound_trans_head(page); | |
163 | ||
164 | if (likely(page != page_head && get_page_unless_zero(page_head))) { | |
165 | /* | |
166 | * page_head wasn't a dangling pointer but it | |
167 | * may not be a head page anymore by the time | |
168 | * we obtain the lock. That is ok as long as it | |
169 | * can't be freed from under us. | |
170 | */ | |
171 | flags = compound_lock_irqsave(page_head); | |
172 | /* here __split_huge_page_refcount won't run anymore */ | |
173 | if (likely(PageTail(page))) { | |
174 | __get_page_tail_foll(page, false); | |
175 | got = true; | |
176 | } | |
177 | compound_unlock_irqrestore(page_head, flags); | |
178 | if (unlikely(!got)) | |
179 | put_page(page_head); | |
180 | } | |
181 | return got; | |
182 | } | |
183 | EXPORT_SYMBOL(__get_page_tail); | |
184 | ||
1d7ea732 | 185 | /** |
7682486b RD |
186 | * put_pages_list() - release a list of pages |
187 | * @pages: list of pages threaded on page->lru | |
1d7ea732 AZ |
188 | * |
189 | * Release a list of pages which are strung together on page.lru. Currently | |
190 | * used by read_cache_pages() and related error recovery code. | |
1d7ea732 AZ |
191 | */ |
192 | void put_pages_list(struct list_head *pages) | |
193 | { | |
194 | while (!list_empty(pages)) { | |
195 | struct page *victim; | |
196 | ||
197 | victim = list_entry(pages->prev, struct page, lru); | |
198 | list_del(&victim->lru); | |
199 | page_cache_release(victim); | |
200 | } | |
201 | } | |
202 | EXPORT_SYMBOL(put_pages_list); | |
203 | ||
3dd7ae8e SL |
204 | static void pagevec_lru_move_fn(struct pagevec *pvec, |
205 | void (*move_fn)(struct page *page, void *arg), | |
206 | void *arg) | |
902aaed0 HH |
207 | { |
208 | int i; | |
902aaed0 | 209 | struct zone *zone = NULL; |
3dd7ae8e | 210 | unsigned long flags = 0; |
902aaed0 HH |
211 | |
212 | for (i = 0; i < pagevec_count(pvec); i++) { | |
213 | struct page *page = pvec->pages[i]; | |
214 | struct zone *pagezone = page_zone(page); | |
215 | ||
216 | if (pagezone != zone) { | |
217 | if (zone) | |
3dd7ae8e | 218 | spin_unlock_irqrestore(&zone->lru_lock, flags); |
902aaed0 | 219 | zone = pagezone; |
3dd7ae8e | 220 | spin_lock_irqsave(&zone->lru_lock, flags); |
902aaed0 | 221 | } |
3dd7ae8e SL |
222 | |
223 | (*move_fn)(page, arg); | |
902aaed0 HH |
224 | } |
225 | if (zone) | |
3dd7ae8e | 226 | spin_unlock_irqrestore(&zone->lru_lock, flags); |
83896fb5 LT |
227 | release_pages(pvec->pages, pvec->nr, pvec->cold); |
228 | pagevec_reinit(pvec); | |
d8505dee SL |
229 | } |
230 | ||
3dd7ae8e SL |
231 | static void pagevec_move_tail_fn(struct page *page, void *arg) |
232 | { | |
233 | int *pgmoved = arg; | |
3dd7ae8e SL |
234 | |
235 | if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) { | |
236 | enum lru_list lru = page_lru_base_type(page); | |
925b7673 JW |
237 | struct lruvec *lruvec; |
238 | ||
239 | lruvec = mem_cgroup_lru_move_lists(page_zone(page), | |
240 | page, lru, lru); | |
241 | list_move_tail(&page->lru, &lruvec->lists[lru]); | |
3dd7ae8e SL |
242 | (*pgmoved)++; |
243 | } | |
244 | } | |
245 | ||
246 | /* | |
247 | * pagevec_move_tail() must be called with IRQ disabled. | |
248 | * Otherwise this may cause nasty races. | |
249 | */ | |
250 | static void pagevec_move_tail(struct pagevec *pvec) | |
251 | { | |
252 | int pgmoved = 0; | |
253 | ||
254 | pagevec_lru_move_fn(pvec, pagevec_move_tail_fn, &pgmoved); | |
255 | __count_vm_events(PGROTATED, pgmoved); | |
256 | } | |
257 | ||
1da177e4 LT |
258 | /* |
259 | * Writeback is about to end against a page which has been marked for immediate | |
260 | * reclaim. If it still appears to be reclaimable, move it to the tail of the | |
902aaed0 | 261 | * inactive list. |
1da177e4 | 262 | */ |
3dd7ae8e | 263 | void rotate_reclaimable_page(struct page *page) |
1da177e4 | 264 | { |
ac6aadb2 | 265 | if (!PageLocked(page) && !PageDirty(page) && !PageActive(page) && |
894bc310 | 266 | !PageUnevictable(page) && PageLRU(page)) { |
ac6aadb2 MS |
267 | struct pagevec *pvec; |
268 | unsigned long flags; | |
269 | ||
270 | page_cache_get(page); | |
271 | local_irq_save(flags); | |
272 | pvec = &__get_cpu_var(lru_rotate_pvecs); | |
273 | if (!pagevec_add(pvec, page)) | |
274 | pagevec_move_tail(pvec); | |
275 | local_irq_restore(flags); | |
276 | } | |
1da177e4 LT |
277 | } |
278 | ||
3e2f41f1 KM |
279 | static void update_page_reclaim_stat(struct zone *zone, struct page *page, |
280 | int file, int rotated) | |
281 | { | |
282 | struct zone_reclaim_stat *reclaim_stat = &zone->reclaim_stat; | |
283 | struct zone_reclaim_stat *memcg_reclaim_stat; | |
284 | ||
285 | memcg_reclaim_stat = mem_cgroup_get_reclaim_stat_from_page(page); | |
286 | ||
287 | reclaim_stat->recent_scanned[file]++; | |
288 | if (rotated) | |
289 | reclaim_stat->recent_rotated[file]++; | |
290 | ||
291 | if (!memcg_reclaim_stat) | |
292 | return; | |
293 | ||
294 | memcg_reclaim_stat->recent_scanned[file]++; | |
295 | if (rotated) | |
296 | memcg_reclaim_stat->recent_rotated[file]++; | |
297 | } | |
298 | ||
eb709b0d | 299 | static void __activate_page(struct page *page, void *arg) |
1da177e4 LT |
300 | { |
301 | struct zone *zone = page_zone(page); | |
744ed144 | 302 | |
744ed144 | 303 | if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) { |
7a608572 LT |
304 | int file = page_is_file_cache(page); |
305 | int lru = page_lru_base_type(page); | |
306 | del_page_from_lru_list(zone, page, lru); | |
744ed144 | 307 | |
7a608572 LT |
308 | SetPageActive(page); |
309 | lru += LRU_ACTIVE; | |
310 | add_page_to_lru_list(zone, page, lru); | |
311 | __count_vm_event(PGACTIVATE); | |
4f98a2fe | 312 | |
7a608572 | 313 | update_page_reclaim_stat(zone, page, file, 1); |
1da177e4 | 314 | } |
eb709b0d SL |
315 | } |
316 | ||
317 | #ifdef CONFIG_SMP | |
318 | static DEFINE_PER_CPU(struct pagevec, activate_page_pvecs); | |
319 | ||
320 | static void activate_page_drain(int cpu) | |
321 | { | |
322 | struct pagevec *pvec = &per_cpu(activate_page_pvecs, cpu); | |
323 | ||
324 | if (pagevec_count(pvec)) | |
325 | pagevec_lru_move_fn(pvec, __activate_page, NULL); | |
326 | } | |
327 | ||
328 | void activate_page(struct page *page) | |
329 | { | |
330 | if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) { | |
331 | struct pagevec *pvec = &get_cpu_var(activate_page_pvecs); | |
332 | ||
333 | page_cache_get(page); | |
334 | if (!pagevec_add(pvec, page)) | |
335 | pagevec_lru_move_fn(pvec, __activate_page, NULL); | |
336 | put_cpu_var(activate_page_pvecs); | |
337 | } | |
338 | } | |
339 | ||
340 | #else | |
341 | static inline void activate_page_drain(int cpu) | |
342 | { | |
343 | } | |
344 | ||
345 | void activate_page(struct page *page) | |
346 | { | |
347 | struct zone *zone = page_zone(page); | |
348 | ||
349 | spin_lock_irq(&zone->lru_lock); | |
350 | __activate_page(page, NULL); | |
1da177e4 LT |
351 | spin_unlock_irq(&zone->lru_lock); |
352 | } | |
eb709b0d | 353 | #endif |
1da177e4 LT |
354 | |
355 | /* | |
356 | * Mark a page as having seen activity. | |
357 | * | |
358 | * inactive,unreferenced -> inactive,referenced | |
359 | * inactive,referenced -> active,unreferenced | |
360 | * active,unreferenced -> active,referenced | |
361 | */ | |
920c7a5d | 362 | void mark_page_accessed(struct page *page) |
1da177e4 | 363 | { |
894bc310 LS |
364 | if (!PageActive(page) && !PageUnevictable(page) && |
365 | PageReferenced(page) && PageLRU(page)) { | |
1da177e4 LT |
366 | activate_page(page); |
367 | ClearPageReferenced(page); | |
368 | } else if (!PageReferenced(page)) { | |
369 | SetPageReferenced(page); | |
370 | } | |
371 | } | |
372 | ||
373 | EXPORT_SYMBOL(mark_page_accessed); | |
374 | ||
f04e9ebb | 375 | void __lru_cache_add(struct page *page, enum lru_list lru) |
1da177e4 | 376 | { |
f04e9ebb | 377 | struct pagevec *pvec = &get_cpu_var(lru_add_pvecs)[lru]; |
1da177e4 LT |
378 | |
379 | page_cache_get(page); | |
380 | if (!pagevec_add(pvec, page)) | |
f04e9ebb | 381 | ____pagevec_lru_add(pvec, lru); |
1da177e4 LT |
382 | put_cpu_var(lru_add_pvecs); |
383 | } | |
47846b06 | 384 | EXPORT_SYMBOL(__lru_cache_add); |
1da177e4 | 385 | |
f04e9ebb KM |
386 | /** |
387 | * lru_cache_add_lru - add a page to a page list | |
388 | * @page: the page to be added to the LRU. | |
389 | * @lru: the LRU list to which the page is added. | |
390 | */ | |
391 | void lru_cache_add_lru(struct page *page, enum lru_list lru) | |
1da177e4 | 392 | { |
f04e9ebb | 393 | if (PageActive(page)) { |
894bc310 | 394 | VM_BUG_ON(PageUnevictable(page)); |
f04e9ebb | 395 | ClearPageActive(page); |
894bc310 LS |
396 | } else if (PageUnevictable(page)) { |
397 | VM_BUG_ON(PageActive(page)); | |
398 | ClearPageUnevictable(page); | |
f04e9ebb | 399 | } |
1da177e4 | 400 | |
894bc310 | 401 | VM_BUG_ON(PageLRU(page) || PageActive(page) || PageUnevictable(page)); |
f04e9ebb | 402 | __lru_cache_add(page, lru); |
1da177e4 LT |
403 | } |
404 | ||
894bc310 LS |
405 | /** |
406 | * add_page_to_unevictable_list - add a page to the unevictable list | |
407 | * @page: the page to be added to the unevictable list | |
408 | * | |
409 | * Add page directly to its zone's unevictable list. To avoid races with | |
410 | * tasks that might be making the page evictable, through eg. munlock, | |
411 | * munmap or exit, while it's not on the lru, we want to add the page | |
412 | * while it's locked or otherwise "invisible" to other tasks. This is | |
413 | * difficult to do when using the pagevec cache, so bypass that. | |
414 | */ | |
415 | void add_page_to_unevictable_list(struct page *page) | |
416 | { | |
417 | struct zone *zone = page_zone(page); | |
418 | ||
419 | spin_lock_irq(&zone->lru_lock); | |
420 | SetPageUnevictable(page); | |
421 | SetPageLRU(page); | |
422 | add_page_to_lru_list(zone, page, LRU_UNEVICTABLE); | |
423 | spin_unlock_irq(&zone->lru_lock); | |
424 | } | |
425 | ||
31560180 MK |
426 | /* |
427 | * If the page can not be invalidated, it is moved to the | |
428 | * inactive list to speed up its reclaim. It is moved to the | |
429 | * head of the list, rather than the tail, to give the flusher | |
430 | * threads some time to write it out, as this is much more | |
431 | * effective than the single-page writeout from reclaim. | |
278df9f4 MK |
432 | * |
433 | * If the page isn't page_mapped and dirty/writeback, the page | |
434 | * could reclaim asap using PG_reclaim. | |
435 | * | |
436 | * 1. active, mapped page -> none | |
437 | * 2. active, dirty/writeback page -> inactive, head, PG_reclaim | |
438 | * 3. inactive, mapped page -> none | |
439 | * 4. inactive, dirty/writeback page -> inactive, head, PG_reclaim | |
440 | * 5. inactive, clean -> inactive, tail | |
441 | * 6. Others -> none | |
442 | * | |
443 | * In 4, why it moves inactive's head, the VM expects the page would | |
444 | * be write it out by flusher threads as this is much more effective | |
445 | * than the single-page writeout from reclaim. | |
31560180 | 446 | */ |
3dd7ae8e | 447 | static void lru_deactivate_fn(struct page *page, void *arg) |
31560180 MK |
448 | { |
449 | int lru, file; | |
278df9f4 | 450 | bool active; |
3dd7ae8e | 451 | struct zone *zone = page_zone(page); |
31560180 | 452 | |
278df9f4 | 453 | if (!PageLRU(page)) |
31560180 MK |
454 | return; |
455 | ||
bad49d9c MK |
456 | if (PageUnevictable(page)) |
457 | return; | |
458 | ||
31560180 MK |
459 | /* Some processes are using the page */ |
460 | if (page_mapped(page)) | |
461 | return; | |
462 | ||
278df9f4 MK |
463 | active = PageActive(page); |
464 | ||
31560180 MK |
465 | file = page_is_file_cache(page); |
466 | lru = page_lru_base_type(page); | |
278df9f4 | 467 | del_page_from_lru_list(zone, page, lru + active); |
31560180 MK |
468 | ClearPageActive(page); |
469 | ClearPageReferenced(page); | |
470 | add_page_to_lru_list(zone, page, lru); | |
31560180 | 471 | |
278df9f4 MK |
472 | if (PageWriteback(page) || PageDirty(page)) { |
473 | /* | |
474 | * PG_reclaim could be raced with end_page_writeback | |
475 | * It can make readahead confusing. But race window | |
476 | * is _really_ small and it's non-critical problem. | |
477 | */ | |
478 | SetPageReclaim(page); | |
479 | } else { | |
925b7673 | 480 | struct lruvec *lruvec; |
278df9f4 MK |
481 | /* |
482 | * The page's writeback ends up during pagevec | |
483 | * We moves tha page into tail of inactive. | |
484 | */ | |
925b7673 JW |
485 | lruvec = mem_cgroup_lru_move_lists(zone, page, lru, lru); |
486 | list_move_tail(&page->lru, &lruvec->lists[lru]); | |
278df9f4 MK |
487 | __count_vm_event(PGROTATED); |
488 | } | |
489 | ||
490 | if (active) | |
491 | __count_vm_event(PGDEACTIVATE); | |
31560180 MK |
492 | update_page_reclaim_stat(zone, page, file, 0); |
493 | } | |
494 | ||
902aaed0 HH |
495 | /* |
496 | * Drain pages out of the cpu's pagevecs. | |
497 | * Either "cpu" is the current CPU, and preemption has already been | |
498 | * disabled; or "cpu" is being hot-unplugged, and is already dead. | |
499 | */ | |
500 | static void drain_cpu_pagevecs(int cpu) | |
1da177e4 | 501 | { |
f04e9ebb | 502 | struct pagevec *pvecs = per_cpu(lru_add_pvecs, cpu); |
902aaed0 | 503 | struct pagevec *pvec; |
f04e9ebb | 504 | int lru; |
1da177e4 | 505 | |
f04e9ebb KM |
506 | for_each_lru(lru) { |
507 | pvec = &pvecs[lru - LRU_BASE]; | |
508 | if (pagevec_count(pvec)) | |
509 | ____pagevec_lru_add(pvec, lru); | |
510 | } | |
902aaed0 HH |
511 | |
512 | pvec = &per_cpu(lru_rotate_pvecs, cpu); | |
513 | if (pagevec_count(pvec)) { | |
514 | unsigned long flags; | |
515 | ||
516 | /* No harm done if a racing interrupt already did this */ | |
517 | local_irq_save(flags); | |
518 | pagevec_move_tail(pvec); | |
519 | local_irq_restore(flags); | |
520 | } | |
31560180 MK |
521 | |
522 | pvec = &per_cpu(lru_deactivate_pvecs, cpu); | |
523 | if (pagevec_count(pvec)) | |
3dd7ae8e | 524 | pagevec_lru_move_fn(pvec, lru_deactivate_fn, NULL); |
eb709b0d SL |
525 | |
526 | activate_page_drain(cpu); | |
31560180 MK |
527 | } |
528 | ||
529 | /** | |
530 | * deactivate_page - forcefully deactivate a page | |
531 | * @page: page to deactivate | |
532 | * | |
533 | * This function hints the VM that @page is a good reclaim candidate, | |
534 | * for example if its invalidation fails due to the page being dirty | |
535 | * or under writeback. | |
536 | */ | |
537 | void deactivate_page(struct page *page) | |
538 | { | |
821ed6bb MK |
539 | /* |
540 | * In a workload with many unevictable page such as mprotect, unevictable | |
541 | * page deactivation for accelerating reclaim is pointless. | |
542 | */ | |
543 | if (PageUnevictable(page)) | |
544 | return; | |
545 | ||
31560180 MK |
546 | if (likely(get_page_unless_zero(page))) { |
547 | struct pagevec *pvec = &get_cpu_var(lru_deactivate_pvecs); | |
548 | ||
549 | if (!pagevec_add(pvec, page)) | |
3dd7ae8e | 550 | pagevec_lru_move_fn(pvec, lru_deactivate_fn, NULL); |
31560180 MK |
551 | put_cpu_var(lru_deactivate_pvecs); |
552 | } | |
80bfed90 AM |
553 | } |
554 | ||
555 | void lru_add_drain(void) | |
556 | { | |
902aaed0 | 557 | drain_cpu_pagevecs(get_cpu()); |
80bfed90 | 558 | put_cpu(); |
1da177e4 LT |
559 | } |
560 | ||
c4028958 | 561 | static void lru_add_drain_per_cpu(struct work_struct *dummy) |
053837fc NP |
562 | { |
563 | lru_add_drain(); | |
564 | } | |
565 | ||
566 | /* | |
567 | * Returns 0 for success | |
568 | */ | |
569 | int lru_add_drain_all(void) | |
570 | { | |
c4028958 | 571 | return schedule_on_each_cpu(lru_add_drain_per_cpu); |
053837fc NP |
572 | } |
573 | ||
1da177e4 LT |
574 | /* |
575 | * Batched page_cache_release(). Decrement the reference count on all the | |
576 | * passed pages. If it fell to zero then remove the page from the LRU and | |
577 | * free it. | |
578 | * | |
579 | * Avoid taking zone->lru_lock if possible, but if it is taken, retain it | |
580 | * for the remainder of the operation. | |
581 | * | |
ab33dc09 FLVC |
582 | * The locking in this function is against shrink_inactive_list(): we recheck |
583 | * the page count inside the lock to see whether shrink_inactive_list() | |
584 | * grabbed the page via the LRU. If it did, give up: shrink_inactive_list() | |
585 | * will free it. | |
1da177e4 LT |
586 | */ |
587 | void release_pages(struct page **pages, int nr, int cold) | |
588 | { | |
589 | int i; | |
cc59850e | 590 | LIST_HEAD(pages_to_free); |
1da177e4 | 591 | struct zone *zone = NULL; |
902aaed0 | 592 | unsigned long uninitialized_var(flags); |
1da177e4 | 593 | |
1da177e4 LT |
594 | for (i = 0; i < nr; i++) { |
595 | struct page *page = pages[i]; | |
1da177e4 | 596 | |
8519fb30 NP |
597 | if (unlikely(PageCompound(page))) { |
598 | if (zone) { | |
902aaed0 | 599 | spin_unlock_irqrestore(&zone->lru_lock, flags); |
8519fb30 NP |
600 | zone = NULL; |
601 | } | |
602 | put_compound_page(page); | |
603 | continue; | |
604 | } | |
605 | ||
b5810039 | 606 | if (!put_page_testzero(page)) |
1da177e4 LT |
607 | continue; |
608 | ||
46453a6e NP |
609 | if (PageLRU(page)) { |
610 | struct zone *pagezone = page_zone(page); | |
894bc310 | 611 | |
46453a6e NP |
612 | if (pagezone != zone) { |
613 | if (zone) | |
902aaed0 HH |
614 | spin_unlock_irqrestore(&zone->lru_lock, |
615 | flags); | |
46453a6e | 616 | zone = pagezone; |
902aaed0 | 617 | spin_lock_irqsave(&zone->lru_lock, flags); |
46453a6e | 618 | } |
725d704e | 619 | VM_BUG_ON(!PageLRU(page)); |
67453911 | 620 | __ClearPageLRU(page); |
1da177e4 | 621 | del_page_from_lru(zone, page); |
46453a6e NP |
622 | } |
623 | ||
cc59850e | 624 | list_add(&page->lru, &pages_to_free); |
1da177e4 LT |
625 | } |
626 | if (zone) | |
902aaed0 | 627 | spin_unlock_irqrestore(&zone->lru_lock, flags); |
1da177e4 | 628 | |
cc59850e | 629 | free_hot_cold_page_list(&pages_to_free, cold); |
1da177e4 | 630 | } |
0be8557b | 631 | EXPORT_SYMBOL(release_pages); |
1da177e4 LT |
632 | |
633 | /* | |
634 | * The pages which we're about to release may be in the deferred lru-addition | |
635 | * queues. That would prevent them from really being freed right now. That's | |
636 | * OK from a correctness point of view but is inefficient - those pages may be | |
637 | * cache-warm and we want to give them back to the page allocator ASAP. | |
638 | * | |
639 | * So __pagevec_release() will drain those queues here. __pagevec_lru_add() | |
640 | * and __pagevec_lru_add_active() call release_pages() directly to avoid | |
641 | * mutual recursion. | |
642 | */ | |
643 | void __pagevec_release(struct pagevec *pvec) | |
644 | { | |
645 | lru_add_drain(); | |
646 | release_pages(pvec->pages, pagevec_count(pvec), pvec->cold); | |
647 | pagevec_reinit(pvec); | |
648 | } | |
649 | ||
7f285701 SF |
650 | EXPORT_SYMBOL(__pagevec_release); |
651 | ||
12d27107 | 652 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE |
71e3aac0 AA |
653 | /* used by __split_huge_page_refcount() */ |
654 | void lru_add_page_tail(struct zone* zone, | |
655 | struct page *page, struct page *page_tail) | |
656 | { | |
657 | int active; | |
658 | enum lru_list lru; | |
659 | const int file = 0; | |
71e3aac0 AA |
660 | |
661 | VM_BUG_ON(!PageHead(page)); | |
662 | VM_BUG_ON(PageCompound(page_tail)); | |
663 | VM_BUG_ON(PageLRU(page_tail)); | |
664 | VM_BUG_ON(!spin_is_locked(&zone->lru_lock)); | |
665 | ||
666 | SetPageLRU(page_tail); | |
667 | ||
668 | if (page_evictable(page_tail, NULL)) { | |
669 | if (PageActive(page)) { | |
670 | SetPageActive(page_tail); | |
671 | active = 1; | |
672 | lru = LRU_ACTIVE_ANON; | |
673 | } else { | |
674 | active = 0; | |
675 | lru = LRU_INACTIVE_ANON; | |
676 | } | |
677 | update_page_reclaim_stat(zone, page_tail, file, active); | |
71e3aac0 AA |
678 | } else { |
679 | SetPageUnevictable(page_tail); | |
12d27107 HD |
680 | lru = LRU_UNEVICTABLE; |
681 | } | |
682 | ||
683 | if (likely(PageLRU(page))) | |
684 | list_add_tail(&page_tail->lru, &page->lru); | |
685 | else { | |
686 | struct list_head *list_head; | |
687 | /* | |
688 | * Head page has not yet been counted, as an hpage, | |
689 | * so we must account for each subpage individually. | |
690 | * | |
691 | * Use the standard add function to put page_tail on the list, | |
692 | * but then correct its position so they all end up in order. | |
693 | */ | |
694 | add_page_to_lru_list(zone, page_tail, lru); | |
695 | list_head = page_tail->lru.prev; | |
696 | list_move_tail(&page_tail->lru, list_head); | |
71e3aac0 AA |
697 | } |
698 | } | |
12d27107 | 699 | #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ |
71e3aac0 | 700 | |
3dd7ae8e SL |
701 | static void ____pagevec_lru_add_fn(struct page *page, void *arg) |
702 | { | |
703 | enum lru_list lru = (enum lru_list)arg; | |
704 | struct zone *zone = page_zone(page); | |
705 | int file = is_file_lru(lru); | |
706 | int active = is_active_lru(lru); | |
707 | ||
708 | VM_BUG_ON(PageActive(page)); | |
709 | VM_BUG_ON(PageUnevictable(page)); | |
710 | VM_BUG_ON(PageLRU(page)); | |
711 | ||
712 | SetPageLRU(page); | |
713 | if (active) | |
714 | SetPageActive(page); | |
715 | update_page_reclaim_stat(zone, page, file, active); | |
716 | add_page_to_lru_list(zone, page, lru); | |
717 | } | |
718 | ||
1da177e4 LT |
719 | /* |
720 | * Add the passed pages to the LRU, then drop the caller's refcount | |
721 | * on them. Reinitialises the caller's pagevec. | |
722 | */ | |
f04e9ebb | 723 | void ____pagevec_lru_add(struct pagevec *pvec, enum lru_list lru) |
1da177e4 | 724 | { |
894bc310 | 725 | VM_BUG_ON(is_unevictable_lru(lru)); |
1da177e4 | 726 | |
3dd7ae8e | 727 | pagevec_lru_move_fn(pvec, ____pagevec_lru_add_fn, (void *)lru); |
1da177e4 LT |
728 | } |
729 | ||
f04e9ebb | 730 | EXPORT_SYMBOL(____pagevec_lru_add); |
1da177e4 | 731 | |
1da177e4 LT |
732 | /** |
733 | * pagevec_lookup - gang pagecache lookup | |
734 | * @pvec: Where the resulting pages are placed | |
735 | * @mapping: The address_space to search | |
736 | * @start: The starting page index | |
737 | * @nr_pages: The maximum number of pages | |
738 | * | |
739 | * pagevec_lookup() will search for and return a group of up to @nr_pages pages | |
740 | * in the mapping. The pages are placed in @pvec. pagevec_lookup() takes a | |
741 | * reference against the pages in @pvec. | |
742 | * | |
743 | * The search returns a group of mapping-contiguous pages with ascending | |
744 | * indexes. There may be holes in the indices due to not-present pages. | |
745 | * | |
746 | * pagevec_lookup() returns the number of pages which were found. | |
747 | */ | |
748 | unsigned pagevec_lookup(struct pagevec *pvec, struct address_space *mapping, | |
749 | pgoff_t start, unsigned nr_pages) | |
750 | { | |
751 | pvec->nr = find_get_pages(mapping, start, nr_pages, pvec->pages); | |
752 | return pagevec_count(pvec); | |
753 | } | |
754 | ||
78539fdf CH |
755 | EXPORT_SYMBOL(pagevec_lookup); |
756 | ||
1da177e4 LT |
757 | unsigned pagevec_lookup_tag(struct pagevec *pvec, struct address_space *mapping, |
758 | pgoff_t *index, int tag, unsigned nr_pages) | |
759 | { | |
760 | pvec->nr = find_get_pages_tag(mapping, index, tag, | |
761 | nr_pages, pvec->pages); | |
762 | return pagevec_count(pvec); | |
763 | } | |
764 | ||
7f285701 | 765 | EXPORT_SYMBOL(pagevec_lookup_tag); |
1da177e4 | 766 | |
1da177e4 LT |
767 | /* |
768 | * Perform any setup for the swap system | |
769 | */ | |
770 | void __init swap_setup(void) | |
771 | { | |
4481374c | 772 | unsigned long megs = totalram_pages >> (20 - PAGE_SHIFT); |
1da177e4 | 773 | |
e0bf68dd PZ |
774 | #ifdef CONFIG_SWAP |
775 | bdi_init(swapper_space.backing_dev_info); | |
776 | #endif | |
777 | ||
1da177e4 LT |
778 | /* Use a smaller cluster for small-memory machines */ |
779 | if (megs < 16) | |
780 | page_cluster = 2; | |
781 | else | |
782 | page_cluster = 3; | |
783 | /* | |
784 | * Right now other parts of the system means that we | |
785 | * _really_ don't want to cluster much more | |
786 | */ | |
1da177e4 | 787 | } |