Commit | Line | Data |
---|---|---|
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> | |
24 | #include <linux/module.h> | |
25 | #include <linux/mm_inline.h> | |
26 | #include <linux/buffer_head.h> /* for try_to_release_page() */ | |
1da177e4 LT |
27 | #include <linux/percpu_counter.h> |
28 | #include <linux/percpu.h> | |
29 | #include <linux/cpu.h> | |
30 | #include <linux/notifier.h> | |
e0bf68dd | 31 | #include <linux/backing-dev.h> |
66e1707b | 32 | #include <linux/memcontrol.h> |
5a0e3ad6 | 33 | #include <linux/gfp.h> |
1da177e4 | 34 | |
64d6519d LS |
35 | #include "internal.h" |
36 | ||
1da177e4 LT |
37 | /* How many pages do we try to swap or page in/out together? */ |
38 | int page_cluster; | |
39 | ||
f04e9ebb | 40 | static DEFINE_PER_CPU(struct pagevec[NR_LRU_LISTS], lru_add_pvecs); |
f84f9504 | 41 | static DEFINE_PER_CPU(struct pagevec, lru_rotate_pvecs); |
31560180 | 42 | static DEFINE_PER_CPU(struct pagevec, lru_deactivate_pvecs); |
902aaed0 | 43 | |
b221385b AB |
44 | /* |
45 | * This path almost never happens for VM activity - pages are normally | |
46 | * freed via pagevecs. But it gets used by networking. | |
47 | */ | |
920c7a5d | 48 | static void __page_cache_release(struct page *page) |
b221385b AB |
49 | { |
50 | if (PageLRU(page)) { | |
51 | unsigned long flags; | |
52 | struct zone *zone = page_zone(page); | |
53 | ||
54 | spin_lock_irqsave(&zone->lru_lock, flags); | |
55 | VM_BUG_ON(!PageLRU(page)); | |
56 | __ClearPageLRU(page); | |
57 | del_page_from_lru(zone, page); | |
58 | spin_unlock_irqrestore(&zone->lru_lock, flags); | |
59 | } | |
91807063 AA |
60 | } |
61 | ||
62 | static void __put_single_page(struct page *page) | |
63 | { | |
64 | __page_cache_release(page); | |
fc91668e | 65 | free_hot_cold_page(page, 0); |
b221385b AB |
66 | } |
67 | ||
91807063 | 68 | static void __put_compound_page(struct page *page) |
1da177e4 | 69 | { |
91807063 | 70 | compound_page_dtor *dtor; |
1da177e4 | 71 | |
91807063 AA |
72 | __page_cache_release(page); |
73 | dtor = get_compound_page_dtor(page); | |
74 | (*dtor)(page); | |
75 | } | |
76 | ||
77 | static void put_compound_page(struct page *page) | |
78 | { | |
79 | if (unlikely(PageTail(page))) { | |
80 | /* __split_huge_page_refcount can run under us */ | |
70b50f94 AA |
81 | struct page *page_head = compound_trans_head(page); |
82 | ||
83 | if (likely(page != page_head && | |
84 | get_page_unless_zero(page_head))) { | |
91807063 AA |
85 | unsigned long flags; |
86 | /* | |
70b50f94 AA |
87 | * page_head wasn't a dangling pointer but it |
88 | * may not be a head page anymore by the time | |
89 | * we obtain the lock. That is ok as long as it | |
90 | * can't be freed from under us. | |
91807063 | 91 | */ |
91807063 AA |
92 | flags = compound_lock_irqsave(page_head); |
93 | if (unlikely(!PageTail(page))) { | |
94 | /* __split_huge_page_refcount run before us */ | |
95 | compound_unlock_irqrestore(page_head, flags); | |
96 | VM_BUG_ON(PageHead(page_head)); | |
91807063 AA |
97 | if (put_page_testzero(page_head)) |
98 | __put_single_page(page_head); | |
99 | out_put_single: | |
100 | if (put_page_testzero(page)) | |
101 | __put_single_page(page); | |
102 | return; | |
103 | } | |
104 | VM_BUG_ON(page_head != page->first_page); | |
105 | /* | |
106 | * We can release the refcount taken by | |
70b50f94 AA |
107 | * get_page_unless_zero() now that |
108 | * __split_huge_page_refcount() is blocked on | |
109 | * the compound_lock. | |
91807063 AA |
110 | */ |
111 | if (put_page_testzero(page_head)) | |
112 | VM_BUG_ON(1); | |
113 | /* __split_huge_page_refcount will wait now */ | |
70b50f94 AA |
114 | VM_BUG_ON(page_mapcount(page) <= 0); |
115 | atomic_dec(&page->_mapcount); | |
91807063 | 116 | VM_BUG_ON(atomic_read(&page_head->_count) <= 0); |
70b50f94 | 117 | VM_BUG_ON(atomic_read(&page->_count) != 0); |
91807063 | 118 | compound_unlock_irqrestore(page_head, flags); |
a95a82e9 AA |
119 | if (put_page_testzero(page_head)) { |
120 | if (PageHead(page_head)) | |
121 | __put_compound_page(page_head); | |
122 | else | |
123 | __put_single_page(page_head); | |
124 | } | |
91807063 AA |
125 | } else { |
126 | /* page_head is a dangling pointer */ | |
127 | VM_BUG_ON(PageTail(page)); | |
128 | goto out_put_single; | |
129 | } | |
130 | } else if (put_page_testzero(page)) { | |
131 | if (PageHead(page)) | |
132 | __put_compound_page(page); | |
133 | else | |
134 | __put_single_page(page); | |
1da177e4 | 135 | } |
8519fb30 NP |
136 | } |
137 | ||
138 | void put_page(struct page *page) | |
139 | { | |
140 | if (unlikely(PageCompound(page))) | |
141 | put_compound_page(page); | |
142 | else if (put_page_testzero(page)) | |
91807063 | 143 | __put_single_page(page); |
1da177e4 LT |
144 | } |
145 | EXPORT_SYMBOL(put_page); | |
1da177e4 | 146 | |
70b50f94 AA |
147 | /* |
148 | * This function is exported but must not be called by anything other | |
149 | * than get_page(). It implements the slow path of get_page(). | |
150 | */ | |
151 | bool __get_page_tail(struct page *page) | |
152 | { | |
153 | /* | |
154 | * This takes care of get_page() if run on a tail page | |
155 | * returned by one of the get_user_pages/follow_page variants. | |
156 | * get_user_pages/follow_page itself doesn't need the compound | |
157 | * lock because it runs __get_page_tail_foll() under the | |
158 | * proper PT lock that already serializes against | |
159 | * split_huge_page(). | |
160 | */ | |
161 | unsigned long flags; | |
162 | bool got = false; | |
163 | struct page *page_head = compound_trans_head(page); | |
164 | ||
165 | if (likely(page != page_head && get_page_unless_zero(page_head))) { | |
166 | /* | |
167 | * page_head wasn't a dangling pointer but it | |
168 | * may not be a head page anymore by the time | |
169 | * we obtain the lock. That is ok as long as it | |
170 | * can't be freed from under us. | |
171 | */ | |
172 | flags = compound_lock_irqsave(page_head); | |
173 | /* here __split_huge_page_refcount won't run anymore */ | |
174 | if (likely(PageTail(page))) { | |
175 | __get_page_tail_foll(page, false); | |
176 | got = true; | |
177 | } | |
178 | compound_unlock_irqrestore(page_head, flags); | |
179 | if (unlikely(!got)) | |
180 | put_page(page_head); | |
181 | } | |
182 | return got; | |
183 | } | |
184 | EXPORT_SYMBOL(__get_page_tail); | |
185 | ||
1d7ea732 | 186 | /** |
7682486b RD |
187 | * put_pages_list() - release a list of pages |
188 | * @pages: list of pages threaded on page->lru | |
1d7ea732 AZ |
189 | * |
190 | * Release a list of pages which are strung together on page.lru. Currently | |
191 | * used by read_cache_pages() and related error recovery code. | |
1d7ea732 AZ |
192 | */ |
193 | void put_pages_list(struct list_head *pages) | |
194 | { | |
195 | while (!list_empty(pages)) { | |
196 | struct page *victim; | |
197 | ||
198 | victim = list_entry(pages->prev, struct page, lru); | |
199 | list_del(&victim->lru); | |
200 | page_cache_release(victim); | |
201 | } | |
202 | } | |
203 | EXPORT_SYMBOL(put_pages_list); | |
204 | ||
3dd7ae8e SL |
205 | static void pagevec_lru_move_fn(struct pagevec *pvec, |
206 | void (*move_fn)(struct page *page, void *arg), | |
207 | void *arg) | |
902aaed0 HH |
208 | { |
209 | int i; | |
902aaed0 | 210 | struct zone *zone = NULL; |
3dd7ae8e | 211 | unsigned long flags = 0; |
902aaed0 HH |
212 | |
213 | for (i = 0; i < pagevec_count(pvec); i++) { | |
214 | struct page *page = pvec->pages[i]; | |
215 | struct zone *pagezone = page_zone(page); | |
216 | ||
217 | if (pagezone != zone) { | |
218 | if (zone) | |
3dd7ae8e | 219 | spin_unlock_irqrestore(&zone->lru_lock, flags); |
902aaed0 | 220 | zone = pagezone; |
3dd7ae8e | 221 | spin_lock_irqsave(&zone->lru_lock, flags); |
902aaed0 | 222 | } |
3dd7ae8e SL |
223 | |
224 | (*move_fn)(page, arg); | |
902aaed0 HH |
225 | } |
226 | if (zone) | |
3dd7ae8e | 227 | spin_unlock_irqrestore(&zone->lru_lock, flags); |
83896fb5 LT |
228 | release_pages(pvec->pages, pvec->nr, pvec->cold); |
229 | pagevec_reinit(pvec); | |
d8505dee SL |
230 | } |
231 | ||
3dd7ae8e SL |
232 | static void pagevec_move_tail_fn(struct page *page, void *arg) |
233 | { | |
234 | int *pgmoved = arg; | |
235 | struct zone *zone = page_zone(page); | |
236 | ||
237 | if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) { | |
238 | enum lru_list lru = page_lru_base_type(page); | |
239 | list_move_tail(&page->lru, &zone->lru[lru].list); | |
240 | mem_cgroup_rotate_reclaimable_page(page); | |
241 | (*pgmoved)++; | |
242 | } | |
243 | } | |
244 | ||
245 | /* | |
246 | * pagevec_move_tail() must be called with IRQ disabled. | |
247 | * Otherwise this may cause nasty races. | |
248 | */ | |
249 | static void pagevec_move_tail(struct pagevec *pvec) | |
250 | { | |
251 | int pgmoved = 0; | |
252 | ||
253 | pagevec_lru_move_fn(pvec, pagevec_move_tail_fn, &pgmoved); | |
254 | __count_vm_events(PGROTATED, pgmoved); | |
255 | } | |
256 | ||
1da177e4 LT |
257 | /* |
258 | * Writeback is about to end against a page which has been marked for immediate | |
259 | * reclaim. If it still appears to be reclaimable, move it to the tail of the | |
902aaed0 | 260 | * inactive list. |
1da177e4 | 261 | */ |
3dd7ae8e | 262 | void rotate_reclaimable_page(struct page *page) |
1da177e4 | 263 | { |
ac6aadb2 | 264 | if (!PageLocked(page) && !PageDirty(page) && !PageActive(page) && |
894bc310 | 265 | !PageUnevictable(page) && PageLRU(page)) { |
ac6aadb2 MS |
266 | struct pagevec *pvec; |
267 | unsigned long flags; | |
268 | ||
269 | page_cache_get(page); | |
270 | local_irq_save(flags); | |
271 | pvec = &__get_cpu_var(lru_rotate_pvecs); | |
272 | if (!pagevec_add(pvec, page)) | |
273 | pagevec_move_tail(pvec); | |
274 | local_irq_restore(flags); | |
275 | } | |
1da177e4 LT |
276 | } |
277 | ||
3e2f41f1 KM |
278 | static void update_page_reclaim_stat(struct zone *zone, struct page *page, |
279 | int file, int rotated) | |
280 | { | |
281 | struct zone_reclaim_stat *reclaim_stat = &zone->reclaim_stat; | |
282 | struct zone_reclaim_stat *memcg_reclaim_stat; | |
283 | ||
284 | memcg_reclaim_stat = mem_cgroup_get_reclaim_stat_from_page(page); | |
285 | ||
286 | reclaim_stat->recent_scanned[file]++; | |
287 | if (rotated) | |
288 | reclaim_stat->recent_rotated[file]++; | |
289 | ||
290 | if (!memcg_reclaim_stat) | |
291 | return; | |
292 | ||
293 | memcg_reclaim_stat->recent_scanned[file]++; | |
294 | if (rotated) | |
295 | memcg_reclaim_stat->recent_rotated[file]++; | |
296 | } | |
297 | ||
eb709b0d | 298 | static void __activate_page(struct page *page, void *arg) |
1da177e4 LT |
299 | { |
300 | struct zone *zone = page_zone(page); | |
744ed144 | 301 | |
744ed144 | 302 | if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) { |
7a608572 LT |
303 | int file = page_is_file_cache(page); |
304 | int lru = page_lru_base_type(page); | |
305 | del_page_from_lru_list(zone, page, lru); | |
744ed144 | 306 | |
7a608572 LT |
307 | SetPageActive(page); |
308 | lru += LRU_ACTIVE; | |
309 | add_page_to_lru_list(zone, page, lru); | |
310 | __count_vm_event(PGACTIVATE); | |
4f98a2fe | 311 | |
7a608572 | 312 | update_page_reclaim_stat(zone, page, file, 1); |
1da177e4 | 313 | } |
eb709b0d SL |
314 | } |
315 | ||
316 | #ifdef CONFIG_SMP | |
317 | static DEFINE_PER_CPU(struct pagevec, activate_page_pvecs); | |
318 | ||
319 | static void activate_page_drain(int cpu) | |
320 | { | |
321 | struct pagevec *pvec = &per_cpu(activate_page_pvecs, cpu); | |
322 | ||
323 | if (pagevec_count(pvec)) | |
324 | pagevec_lru_move_fn(pvec, __activate_page, NULL); | |
325 | } | |
326 | ||
327 | void activate_page(struct page *page) | |
328 | { | |
329 | if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) { | |
330 | struct pagevec *pvec = &get_cpu_var(activate_page_pvecs); | |
331 | ||
332 | page_cache_get(page); | |
333 | if (!pagevec_add(pvec, page)) | |
334 | pagevec_lru_move_fn(pvec, __activate_page, NULL); | |
335 | put_cpu_var(activate_page_pvecs); | |
336 | } | |
337 | } | |
338 | ||
339 | #else | |
340 | static inline void activate_page_drain(int cpu) | |
341 | { | |
342 | } | |
343 | ||
344 | void activate_page(struct page *page) | |
345 | { | |
346 | struct zone *zone = page_zone(page); | |
347 | ||
348 | spin_lock_irq(&zone->lru_lock); | |
349 | __activate_page(page, NULL); | |
1da177e4 LT |
350 | spin_unlock_irq(&zone->lru_lock); |
351 | } | |
eb709b0d | 352 | #endif |
1da177e4 LT |
353 | |
354 | /* | |
355 | * Mark a page as having seen activity. | |
356 | * | |
357 | * inactive,unreferenced -> inactive,referenced | |
358 | * inactive,referenced -> active,unreferenced | |
359 | * active,unreferenced -> active,referenced | |
360 | */ | |
920c7a5d | 361 | void mark_page_accessed(struct page *page) |
1da177e4 | 362 | { |
894bc310 LS |
363 | if (!PageActive(page) && !PageUnevictable(page) && |
364 | PageReferenced(page) && PageLRU(page)) { | |
1da177e4 LT |
365 | activate_page(page); |
366 | ClearPageReferenced(page); | |
367 | } else if (!PageReferenced(page)) { | |
368 | SetPageReferenced(page); | |
369 | } | |
370 | } | |
371 | ||
372 | EXPORT_SYMBOL(mark_page_accessed); | |
373 | ||
f04e9ebb | 374 | void __lru_cache_add(struct page *page, enum lru_list lru) |
1da177e4 | 375 | { |
f04e9ebb | 376 | struct pagevec *pvec = &get_cpu_var(lru_add_pvecs)[lru]; |
1da177e4 LT |
377 | |
378 | page_cache_get(page); | |
379 | if (!pagevec_add(pvec, page)) | |
f04e9ebb | 380 | ____pagevec_lru_add(pvec, lru); |
1da177e4 LT |
381 | put_cpu_var(lru_add_pvecs); |
382 | } | |
47846b06 | 383 | EXPORT_SYMBOL(__lru_cache_add); |
1da177e4 | 384 | |
f04e9ebb KM |
385 | /** |
386 | * lru_cache_add_lru - add a page to a page list | |
387 | * @page: the page to be added to the LRU. | |
388 | * @lru: the LRU list to which the page is added. | |
389 | */ | |
390 | void lru_cache_add_lru(struct page *page, enum lru_list lru) | |
1da177e4 | 391 | { |
f04e9ebb | 392 | if (PageActive(page)) { |
894bc310 | 393 | VM_BUG_ON(PageUnevictable(page)); |
f04e9ebb | 394 | ClearPageActive(page); |
894bc310 LS |
395 | } else if (PageUnevictable(page)) { |
396 | VM_BUG_ON(PageActive(page)); | |
397 | ClearPageUnevictable(page); | |
f04e9ebb | 398 | } |
1da177e4 | 399 | |
894bc310 | 400 | VM_BUG_ON(PageLRU(page) || PageActive(page) || PageUnevictable(page)); |
f04e9ebb | 401 | __lru_cache_add(page, lru); |
1da177e4 LT |
402 | } |
403 | ||
894bc310 LS |
404 | /** |
405 | * add_page_to_unevictable_list - add a page to the unevictable list | |
406 | * @page: the page to be added to the unevictable list | |
407 | * | |
408 | * Add page directly to its zone's unevictable list. To avoid races with | |
409 | * tasks that might be making the page evictable, through eg. munlock, | |
410 | * munmap or exit, while it's not on the lru, we want to add the page | |
411 | * while it's locked or otherwise "invisible" to other tasks. This is | |
412 | * difficult to do when using the pagevec cache, so bypass that. | |
413 | */ | |
414 | void add_page_to_unevictable_list(struct page *page) | |
415 | { | |
416 | struct zone *zone = page_zone(page); | |
417 | ||
418 | spin_lock_irq(&zone->lru_lock); | |
419 | SetPageUnevictable(page); | |
420 | SetPageLRU(page); | |
421 | add_page_to_lru_list(zone, page, LRU_UNEVICTABLE); | |
422 | spin_unlock_irq(&zone->lru_lock); | |
423 | } | |
424 | ||
31560180 MK |
425 | /* |
426 | * If the page can not be invalidated, it is moved to the | |
427 | * inactive list to speed up its reclaim. It is moved to the | |
428 | * head of the list, rather than the tail, to give the flusher | |
429 | * threads some time to write it out, as this is much more | |
430 | * effective than the single-page writeout from reclaim. | |
278df9f4 MK |
431 | * |
432 | * If the page isn't page_mapped and dirty/writeback, the page | |
433 | * could reclaim asap using PG_reclaim. | |
434 | * | |
435 | * 1. active, mapped page -> none | |
436 | * 2. active, dirty/writeback page -> inactive, head, PG_reclaim | |
437 | * 3. inactive, mapped page -> none | |
438 | * 4. inactive, dirty/writeback page -> inactive, head, PG_reclaim | |
439 | * 5. inactive, clean -> inactive, tail | |
440 | * 6. Others -> none | |
441 | * | |
442 | * In 4, why it moves inactive's head, the VM expects the page would | |
443 | * be write it out by flusher threads as this is much more effective | |
444 | * than the single-page writeout from reclaim. | |
31560180 | 445 | */ |
3dd7ae8e | 446 | static void lru_deactivate_fn(struct page *page, void *arg) |
31560180 MK |
447 | { |
448 | int lru, file; | |
278df9f4 | 449 | bool active; |
3dd7ae8e | 450 | struct zone *zone = page_zone(page); |
31560180 | 451 | |
278df9f4 | 452 | if (!PageLRU(page)) |
31560180 MK |
453 | return; |
454 | ||
bad49d9c MK |
455 | if (PageUnevictable(page)) |
456 | return; | |
457 | ||
31560180 MK |
458 | /* Some processes are using the page */ |
459 | if (page_mapped(page)) | |
460 | return; | |
461 | ||
278df9f4 MK |
462 | active = PageActive(page); |
463 | ||
31560180 MK |
464 | file = page_is_file_cache(page); |
465 | lru = page_lru_base_type(page); | |
278df9f4 | 466 | del_page_from_lru_list(zone, page, lru + active); |
31560180 MK |
467 | ClearPageActive(page); |
468 | ClearPageReferenced(page); | |
469 | add_page_to_lru_list(zone, page, lru); | |
31560180 | 470 | |
278df9f4 MK |
471 | if (PageWriteback(page) || PageDirty(page)) { |
472 | /* | |
473 | * PG_reclaim could be raced with end_page_writeback | |
474 | * It can make readahead confusing. But race window | |
475 | * is _really_ small and it's non-critical problem. | |
476 | */ | |
477 | SetPageReclaim(page); | |
478 | } else { | |
479 | /* | |
480 | * The page's writeback ends up during pagevec | |
481 | * We moves tha page into tail of inactive. | |
482 | */ | |
483 | list_move_tail(&page->lru, &zone->lru[lru].list); | |
484 | mem_cgroup_rotate_reclaimable_page(page); | |
485 | __count_vm_event(PGROTATED); | |
486 | } | |
487 | ||
488 | if (active) | |
489 | __count_vm_event(PGDEACTIVATE); | |
31560180 MK |
490 | update_page_reclaim_stat(zone, page, file, 0); |
491 | } | |
492 | ||
902aaed0 HH |
493 | /* |
494 | * Drain pages out of the cpu's pagevecs. | |
495 | * Either "cpu" is the current CPU, and preemption has already been | |
496 | * disabled; or "cpu" is being hot-unplugged, and is already dead. | |
497 | */ | |
498 | static void drain_cpu_pagevecs(int cpu) | |
1da177e4 | 499 | { |
f04e9ebb | 500 | struct pagevec *pvecs = per_cpu(lru_add_pvecs, cpu); |
902aaed0 | 501 | struct pagevec *pvec; |
f04e9ebb | 502 | int lru; |
1da177e4 | 503 | |
f04e9ebb KM |
504 | for_each_lru(lru) { |
505 | pvec = &pvecs[lru - LRU_BASE]; | |
506 | if (pagevec_count(pvec)) | |
507 | ____pagevec_lru_add(pvec, lru); | |
508 | } | |
902aaed0 HH |
509 | |
510 | pvec = &per_cpu(lru_rotate_pvecs, cpu); | |
511 | if (pagevec_count(pvec)) { | |
512 | unsigned long flags; | |
513 | ||
514 | /* No harm done if a racing interrupt already did this */ | |
515 | local_irq_save(flags); | |
516 | pagevec_move_tail(pvec); | |
517 | local_irq_restore(flags); | |
518 | } | |
31560180 MK |
519 | |
520 | pvec = &per_cpu(lru_deactivate_pvecs, cpu); | |
521 | if (pagevec_count(pvec)) | |
3dd7ae8e | 522 | pagevec_lru_move_fn(pvec, lru_deactivate_fn, NULL); |
eb709b0d SL |
523 | |
524 | activate_page_drain(cpu); | |
31560180 MK |
525 | } |
526 | ||
527 | /** | |
528 | * deactivate_page - forcefully deactivate a page | |
529 | * @page: page to deactivate | |
530 | * | |
531 | * This function hints the VM that @page is a good reclaim candidate, | |
532 | * for example if its invalidation fails due to the page being dirty | |
533 | * or under writeback. | |
534 | */ | |
535 | void deactivate_page(struct page *page) | |
536 | { | |
821ed6bb MK |
537 | /* |
538 | * In a workload with many unevictable page such as mprotect, unevictable | |
539 | * page deactivation for accelerating reclaim is pointless. | |
540 | */ | |
541 | if (PageUnevictable(page)) | |
542 | return; | |
543 | ||
31560180 MK |
544 | if (likely(get_page_unless_zero(page))) { |
545 | struct pagevec *pvec = &get_cpu_var(lru_deactivate_pvecs); | |
546 | ||
547 | if (!pagevec_add(pvec, page)) | |
3dd7ae8e | 548 | pagevec_lru_move_fn(pvec, lru_deactivate_fn, NULL); |
31560180 MK |
549 | put_cpu_var(lru_deactivate_pvecs); |
550 | } | |
80bfed90 AM |
551 | } |
552 | ||
553 | void lru_add_drain(void) | |
554 | { | |
902aaed0 | 555 | drain_cpu_pagevecs(get_cpu()); |
80bfed90 | 556 | put_cpu(); |
1da177e4 LT |
557 | } |
558 | ||
c4028958 | 559 | static void lru_add_drain_per_cpu(struct work_struct *dummy) |
053837fc NP |
560 | { |
561 | lru_add_drain(); | |
562 | } | |
563 | ||
564 | /* | |
565 | * Returns 0 for success | |
566 | */ | |
567 | int lru_add_drain_all(void) | |
568 | { | |
c4028958 | 569 | return schedule_on_each_cpu(lru_add_drain_per_cpu); |
053837fc NP |
570 | } |
571 | ||
1da177e4 LT |
572 | /* |
573 | * Batched page_cache_release(). Decrement the reference count on all the | |
574 | * passed pages. If it fell to zero then remove the page from the LRU and | |
575 | * free it. | |
576 | * | |
577 | * Avoid taking zone->lru_lock if possible, but if it is taken, retain it | |
578 | * for the remainder of the operation. | |
579 | * | |
ab33dc09 FLVC |
580 | * The locking in this function is against shrink_inactive_list(): we recheck |
581 | * the page count inside the lock to see whether shrink_inactive_list() | |
582 | * grabbed the page via the LRU. If it did, give up: shrink_inactive_list() | |
583 | * will free it. | |
1da177e4 LT |
584 | */ |
585 | void release_pages(struct page **pages, int nr, int cold) | |
586 | { | |
587 | int i; | |
588 | struct pagevec pages_to_free; | |
589 | struct zone *zone = NULL; | |
902aaed0 | 590 | unsigned long uninitialized_var(flags); |
1da177e4 LT |
591 | |
592 | pagevec_init(&pages_to_free, cold); | |
593 | for (i = 0; i < nr; i++) { | |
594 | struct page *page = pages[i]; | |
1da177e4 | 595 | |
8519fb30 NP |
596 | if (unlikely(PageCompound(page))) { |
597 | if (zone) { | |
902aaed0 | 598 | spin_unlock_irqrestore(&zone->lru_lock, flags); |
8519fb30 NP |
599 | zone = NULL; |
600 | } | |
601 | put_compound_page(page); | |
602 | continue; | |
603 | } | |
604 | ||
b5810039 | 605 | if (!put_page_testzero(page)) |
1da177e4 LT |
606 | continue; |
607 | ||
46453a6e NP |
608 | if (PageLRU(page)) { |
609 | struct zone *pagezone = page_zone(page); | |
894bc310 | 610 | |
46453a6e NP |
611 | if (pagezone != zone) { |
612 | if (zone) | |
902aaed0 HH |
613 | spin_unlock_irqrestore(&zone->lru_lock, |
614 | flags); | |
46453a6e | 615 | zone = pagezone; |
902aaed0 | 616 | spin_lock_irqsave(&zone->lru_lock, flags); |
46453a6e | 617 | } |
725d704e | 618 | VM_BUG_ON(!PageLRU(page)); |
67453911 | 619 | __ClearPageLRU(page); |
1da177e4 | 620 | del_page_from_lru(zone, page); |
46453a6e NP |
621 | } |
622 | ||
623 | if (!pagevec_add(&pages_to_free, page)) { | |
624 | if (zone) { | |
902aaed0 | 625 | spin_unlock_irqrestore(&zone->lru_lock, flags); |
46453a6e | 626 | zone = NULL; |
1da177e4 | 627 | } |
46453a6e NP |
628 | __pagevec_free(&pages_to_free); |
629 | pagevec_reinit(&pages_to_free); | |
630 | } | |
1da177e4 LT |
631 | } |
632 | if (zone) | |
902aaed0 | 633 | spin_unlock_irqrestore(&zone->lru_lock, flags); |
1da177e4 LT |
634 | |
635 | pagevec_free(&pages_to_free); | |
636 | } | |
0be8557b | 637 | EXPORT_SYMBOL(release_pages); |
1da177e4 LT |
638 | |
639 | /* | |
640 | * The pages which we're about to release may be in the deferred lru-addition | |
641 | * queues. That would prevent them from really being freed right now. That's | |
642 | * OK from a correctness point of view but is inefficient - those pages may be | |
643 | * cache-warm and we want to give them back to the page allocator ASAP. | |
644 | * | |
645 | * So __pagevec_release() will drain those queues here. __pagevec_lru_add() | |
646 | * and __pagevec_lru_add_active() call release_pages() directly to avoid | |
647 | * mutual recursion. | |
648 | */ | |
649 | void __pagevec_release(struct pagevec *pvec) | |
650 | { | |
651 | lru_add_drain(); | |
652 | release_pages(pvec->pages, pagevec_count(pvec), pvec->cold); | |
653 | pagevec_reinit(pvec); | |
654 | } | |
655 | ||
7f285701 SF |
656 | EXPORT_SYMBOL(__pagevec_release); |
657 | ||
71e3aac0 AA |
658 | /* used by __split_huge_page_refcount() */ |
659 | void lru_add_page_tail(struct zone* zone, | |
660 | struct page *page, struct page *page_tail) | |
661 | { | |
662 | int active; | |
663 | enum lru_list lru; | |
664 | const int file = 0; | |
665 | struct list_head *head; | |
666 | ||
667 | VM_BUG_ON(!PageHead(page)); | |
668 | VM_BUG_ON(PageCompound(page_tail)); | |
669 | VM_BUG_ON(PageLRU(page_tail)); | |
670 | VM_BUG_ON(!spin_is_locked(&zone->lru_lock)); | |
671 | ||
672 | SetPageLRU(page_tail); | |
673 | ||
674 | if (page_evictable(page_tail, NULL)) { | |
675 | if (PageActive(page)) { | |
676 | SetPageActive(page_tail); | |
677 | active = 1; | |
678 | lru = LRU_ACTIVE_ANON; | |
679 | } else { | |
680 | active = 0; | |
681 | lru = LRU_INACTIVE_ANON; | |
682 | } | |
683 | update_page_reclaim_stat(zone, page_tail, file, active); | |
684 | if (likely(PageLRU(page))) | |
685 | head = page->lru.prev; | |
686 | else | |
687 | head = &zone->lru[lru].list; | |
688 | __add_page_to_lru_list(zone, page_tail, lru, head); | |
689 | } else { | |
690 | SetPageUnevictable(page_tail); | |
691 | add_page_to_lru_list(zone, page_tail, LRU_UNEVICTABLE); | |
692 | } | |
693 | } | |
694 | ||
3dd7ae8e SL |
695 | static void ____pagevec_lru_add_fn(struct page *page, void *arg) |
696 | { | |
697 | enum lru_list lru = (enum lru_list)arg; | |
698 | struct zone *zone = page_zone(page); | |
699 | int file = is_file_lru(lru); | |
700 | int active = is_active_lru(lru); | |
701 | ||
702 | VM_BUG_ON(PageActive(page)); | |
703 | VM_BUG_ON(PageUnevictable(page)); | |
704 | VM_BUG_ON(PageLRU(page)); | |
705 | ||
706 | SetPageLRU(page); | |
707 | if (active) | |
708 | SetPageActive(page); | |
709 | update_page_reclaim_stat(zone, page, file, active); | |
710 | add_page_to_lru_list(zone, page, lru); | |
711 | } | |
712 | ||
1da177e4 LT |
713 | /* |
714 | * Add the passed pages to the LRU, then drop the caller's refcount | |
715 | * on them. Reinitialises the caller's pagevec. | |
716 | */ | |
f04e9ebb | 717 | void ____pagevec_lru_add(struct pagevec *pvec, enum lru_list lru) |
1da177e4 | 718 | { |
894bc310 | 719 | VM_BUG_ON(is_unevictable_lru(lru)); |
1da177e4 | 720 | |
3dd7ae8e | 721 | pagevec_lru_move_fn(pvec, ____pagevec_lru_add_fn, (void *)lru); |
1da177e4 LT |
722 | } |
723 | ||
f04e9ebb | 724 | EXPORT_SYMBOL(____pagevec_lru_add); |
1da177e4 LT |
725 | |
726 | /* | |
727 | * Try to drop buffers from the pages in a pagevec | |
728 | */ | |
729 | void pagevec_strip(struct pagevec *pvec) | |
730 | { | |
731 | int i; | |
732 | ||
733 | for (i = 0; i < pagevec_count(pvec); i++) { | |
734 | struct page *page = pvec->pages[i]; | |
735 | ||
266cf658 DH |
736 | if (page_has_private(page) && trylock_page(page)) { |
737 | if (page_has_private(page)) | |
5b40dc78 | 738 | try_to_release_page(page, 0); |
1da177e4 LT |
739 | unlock_page(page); |
740 | } | |
741 | } | |
742 | } | |
743 | ||
744 | /** | |
745 | * pagevec_lookup - gang pagecache lookup | |
746 | * @pvec: Where the resulting pages are placed | |
747 | * @mapping: The address_space to search | |
748 | * @start: The starting page index | |
749 | * @nr_pages: The maximum number of pages | |
750 | * | |
751 | * pagevec_lookup() will search for and return a group of up to @nr_pages pages | |
752 | * in the mapping. The pages are placed in @pvec. pagevec_lookup() takes a | |
753 | * reference against the pages in @pvec. | |
754 | * | |
755 | * The search returns a group of mapping-contiguous pages with ascending | |
756 | * indexes. There may be holes in the indices due to not-present pages. | |
757 | * | |
758 | * pagevec_lookup() returns the number of pages which were found. | |
759 | */ | |
760 | unsigned pagevec_lookup(struct pagevec *pvec, struct address_space *mapping, | |
761 | pgoff_t start, unsigned nr_pages) | |
762 | { | |
763 | pvec->nr = find_get_pages(mapping, start, nr_pages, pvec->pages); | |
764 | return pagevec_count(pvec); | |
765 | } | |
766 | ||
78539fdf CH |
767 | EXPORT_SYMBOL(pagevec_lookup); |
768 | ||
1da177e4 LT |
769 | unsigned pagevec_lookup_tag(struct pagevec *pvec, struct address_space *mapping, |
770 | pgoff_t *index, int tag, unsigned nr_pages) | |
771 | { | |
772 | pvec->nr = find_get_pages_tag(mapping, index, tag, | |
773 | nr_pages, pvec->pages); | |
774 | return pagevec_count(pvec); | |
775 | } | |
776 | ||
7f285701 | 777 | EXPORT_SYMBOL(pagevec_lookup_tag); |
1da177e4 | 778 | |
1da177e4 LT |
779 | /* |
780 | * Perform any setup for the swap system | |
781 | */ | |
782 | void __init swap_setup(void) | |
783 | { | |
4481374c | 784 | unsigned long megs = totalram_pages >> (20 - PAGE_SHIFT); |
1da177e4 | 785 | |
e0bf68dd PZ |
786 | #ifdef CONFIG_SWAP |
787 | bdi_init(swapper_space.backing_dev_info); | |
788 | #endif | |
789 | ||
1da177e4 LT |
790 | /* Use a smaller cluster for small-memory machines */ |
791 | if (megs < 16) | |
792 | page_cluster = 2; | |
793 | else | |
794 | page_cluster = 3; | |
795 | /* | |
796 | * Right now other parts of the system means that we | |
797 | * _really_ don't want to cluster much more | |
798 | */ | |
1da177e4 | 799 | } |