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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> | |
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 */ | |
81 | struct page *page_head = page->first_page; | |
82 | smp_rmb(); | |
83 | /* | |
84 | * If PageTail is still set after smp_rmb() we can be sure | |
85 | * that the page->first_page we read wasn't a dangling pointer. | |
86 | * See __split_huge_page_refcount() smp_wmb(). | |
87 | */ | |
88 | if (likely(PageTail(page) && get_page_unless_zero(page_head))) { | |
89 | unsigned long flags; | |
90 | /* | |
91 | * Verify that our page_head wasn't converted | |
92 | * to a a regular page before we got a | |
93 | * reference on it. | |
94 | */ | |
95 | if (unlikely(!PageHead(page_head))) { | |
96 | /* PageHead is cleared after PageTail */ | |
97 | smp_rmb(); | |
98 | VM_BUG_ON(PageTail(page)); | |
99 | goto out_put_head; | |
100 | } | |
101 | /* | |
102 | * Only run compound_lock on a valid PageHead, | |
103 | * after having it pinned with | |
104 | * get_page_unless_zero() above. | |
105 | */ | |
106 | smp_mb(); | |
107 | /* page_head wasn't a dangling pointer */ | |
108 | flags = compound_lock_irqsave(page_head); | |
109 | if (unlikely(!PageTail(page))) { | |
110 | /* __split_huge_page_refcount run before us */ | |
111 | compound_unlock_irqrestore(page_head, flags); | |
112 | VM_BUG_ON(PageHead(page_head)); | |
113 | out_put_head: | |
114 | if (put_page_testzero(page_head)) | |
115 | __put_single_page(page_head); | |
116 | out_put_single: | |
117 | if (put_page_testzero(page)) | |
118 | __put_single_page(page); | |
119 | return; | |
120 | } | |
121 | VM_BUG_ON(page_head != page->first_page); | |
122 | /* | |
123 | * We can release the refcount taken by | |
124 | * get_page_unless_zero now that | |
125 | * split_huge_page_refcount is blocked on the | |
126 | * compound_lock. | |
127 | */ | |
128 | if (put_page_testzero(page_head)) | |
129 | VM_BUG_ON(1); | |
130 | /* __split_huge_page_refcount will wait now */ | |
131 | VM_BUG_ON(atomic_read(&page->_count) <= 0); | |
132 | atomic_dec(&page->_count); | |
133 | VM_BUG_ON(atomic_read(&page_head->_count) <= 0); | |
134 | compound_unlock_irqrestore(page_head, flags); | |
a95a82e9 AA |
135 | if (put_page_testzero(page_head)) { |
136 | if (PageHead(page_head)) | |
137 | __put_compound_page(page_head); | |
138 | else | |
139 | __put_single_page(page_head); | |
140 | } | |
91807063 AA |
141 | } else { |
142 | /* page_head is a dangling pointer */ | |
143 | VM_BUG_ON(PageTail(page)); | |
144 | goto out_put_single; | |
145 | } | |
146 | } else if (put_page_testzero(page)) { | |
147 | if (PageHead(page)) | |
148 | __put_compound_page(page); | |
149 | else | |
150 | __put_single_page(page); | |
1da177e4 | 151 | } |
8519fb30 NP |
152 | } |
153 | ||
154 | void put_page(struct page *page) | |
155 | { | |
156 | if (unlikely(PageCompound(page))) | |
157 | put_compound_page(page); | |
158 | else if (put_page_testzero(page)) | |
91807063 | 159 | __put_single_page(page); |
1da177e4 LT |
160 | } |
161 | EXPORT_SYMBOL(put_page); | |
1da177e4 | 162 | |
1d7ea732 | 163 | /** |
7682486b RD |
164 | * put_pages_list() - release a list of pages |
165 | * @pages: list of pages threaded on page->lru | |
1d7ea732 AZ |
166 | * |
167 | * Release a list of pages which are strung together on page.lru. Currently | |
168 | * used by read_cache_pages() and related error recovery code. | |
1d7ea732 AZ |
169 | */ |
170 | void put_pages_list(struct list_head *pages) | |
171 | { | |
172 | while (!list_empty(pages)) { | |
173 | struct page *victim; | |
174 | ||
175 | victim = list_entry(pages->prev, struct page, lru); | |
176 | list_del(&victim->lru); | |
177 | page_cache_release(victim); | |
178 | } | |
179 | } | |
180 | EXPORT_SYMBOL(put_pages_list); | |
181 | ||
83896fb5 LT |
182 | /* |
183 | * pagevec_move_tail() must be called with IRQ disabled. | |
184 | * Otherwise this may cause nasty races. | |
185 | */ | |
186 | static void pagevec_move_tail(struct pagevec *pvec) | |
902aaed0 HH |
187 | { |
188 | int i; | |
83896fb5 | 189 | int pgmoved = 0; |
902aaed0 HH |
190 | struct zone *zone = NULL; |
191 | ||
192 | for (i = 0; i < pagevec_count(pvec); i++) { | |
193 | struct page *page = pvec->pages[i]; | |
194 | struct zone *pagezone = page_zone(page); | |
195 | ||
196 | if (pagezone != zone) { | |
197 | if (zone) | |
83896fb5 | 198 | spin_unlock(&zone->lru_lock); |
902aaed0 | 199 | zone = pagezone; |
83896fb5 LT |
200 | spin_lock(&zone->lru_lock); |
201 | } | |
202 | if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) { | |
3f58a829 | 203 | enum lru_list lru = page_lru_base_type(page); |
83896fb5 | 204 | list_move_tail(&page->lru, &zone->lru[lru].list); |
3f58a829 | 205 | mem_cgroup_rotate_reclaimable_page(page); |
83896fb5 | 206 | pgmoved++; |
902aaed0 HH |
207 | } |
208 | } | |
209 | if (zone) | |
83896fb5 | 210 | spin_unlock(&zone->lru_lock); |
d8505dee | 211 | __count_vm_events(PGROTATED, pgmoved); |
83896fb5 LT |
212 | release_pages(pvec->pages, pvec->nr, pvec->cold); |
213 | pagevec_reinit(pvec); | |
d8505dee SL |
214 | } |
215 | ||
1da177e4 LT |
216 | /* |
217 | * Writeback is about to end against a page which has been marked for immediate | |
218 | * reclaim. If it still appears to be reclaimable, move it to the tail of the | |
902aaed0 | 219 | * inactive list. |
1da177e4 | 220 | */ |
83896fb5 | 221 | void rotate_reclaimable_page(struct page *page) |
1da177e4 | 222 | { |
ac6aadb2 | 223 | if (!PageLocked(page) && !PageDirty(page) && !PageActive(page) && |
894bc310 | 224 | !PageUnevictable(page) && PageLRU(page)) { |
ac6aadb2 MS |
225 | struct pagevec *pvec; |
226 | unsigned long flags; | |
227 | ||
228 | page_cache_get(page); | |
229 | local_irq_save(flags); | |
230 | pvec = &__get_cpu_var(lru_rotate_pvecs); | |
231 | if (!pagevec_add(pvec, page)) | |
232 | pagevec_move_tail(pvec); | |
233 | local_irq_restore(flags); | |
234 | } | |
1da177e4 LT |
235 | } |
236 | ||
3e2f41f1 KM |
237 | static void update_page_reclaim_stat(struct zone *zone, struct page *page, |
238 | int file, int rotated) | |
239 | { | |
240 | struct zone_reclaim_stat *reclaim_stat = &zone->reclaim_stat; | |
241 | struct zone_reclaim_stat *memcg_reclaim_stat; | |
242 | ||
243 | memcg_reclaim_stat = mem_cgroup_get_reclaim_stat_from_page(page); | |
244 | ||
245 | reclaim_stat->recent_scanned[file]++; | |
246 | if (rotated) | |
247 | reclaim_stat->recent_rotated[file]++; | |
248 | ||
249 | if (!memcg_reclaim_stat) | |
250 | return; | |
251 | ||
252 | memcg_reclaim_stat->recent_scanned[file]++; | |
253 | if (rotated) | |
254 | memcg_reclaim_stat->recent_rotated[file]++; | |
255 | } | |
256 | ||
1da177e4 | 257 | /* |
7a608572 | 258 | * FIXME: speed this up? |
1da177e4 | 259 | */ |
7a608572 | 260 | void activate_page(struct page *page) |
1da177e4 LT |
261 | { |
262 | struct zone *zone = page_zone(page); | |
744ed144 | 263 | |
7a608572 | 264 | spin_lock_irq(&zone->lru_lock); |
744ed144 | 265 | if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) { |
7a608572 LT |
266 | int file = page_is_file_cache(page); |
267 | int lru = page_lru_base_type(page); | |
268 | del_page_from_lru_list(zone, page, lru); | |
744ed144 | 269 | |
7a608572 LT |
270 | SetPageActive(page); |
271 | lru += LRU_ACTIVE; | |
272 | add_page_to_lru_list(zone, page, lru); | |
273 | __count_vm_event(PGACTIVATE); | |
4f98a2fe | 274 | |
7a608572 | 275 | update_page_reclaim_stat(zone, page, file, 1); |
1da177e4 LT |
276 | } |
277 | spin_unlock_irq(&zone->lru_lock); | |
278 | } | |
279 | ||
280 | /* | |
281 | * Mark a page as having seen activity. | |
282 | * | |
283 | * inactive,unreferenced -> inactive,referenced | |
284 | * inactive,referenced -> active,unreferenced | |
285 | * active,unreferenced -> active,referenced | |
286 | */ | |
920c7a5d | 287 | void mark_page_accessed(struct page *page) |
1da177e4 | 288 | { |
894bc310 LS |
289 | if (!PageActive(page) && !PageUnevictable(page) && |
290 | PageReferenced(page) && PageLRU(page)) { | |
1da177e4 LT |
291 | activate_page(page); |
292 | ClearPageReferenced(page); | |
293 | } else if (!PageReferenced(page)) { | |
294 | SetPageReferenced(page); | |
295 | } | |
296 | } | |
297 | ||
298 | EXPORT_SYMBOL(mark_page_accessed); | |
299 | ||
f04e9ebb | 300 | void __lru_cache_add(struct page *page, enum lru_list lru) |
1da177e4 | 301 | { |
f04e9ebb | 302 | struct pagevec *pvec = &get_cpu_var(lru_add_pvecs)[lru]; |
1da177e4 LT |
303 | |
304 | page_cache_get(page); | |
305 | if (!pagevec_add(pvec, page)) | |
f04e9ebb | 306 | ____pagevec_lru_add(pvec, lru); |
1da177e4 LT |
307 | put_cpu_var(lru_add_pvecs); |
308 | } | |
47846b06 | 309 | EXPORT_SYMBOL(__lru_cache_add); |
1da177e4 | 310 | |
f04e9ebb KM |
311 | /** |
312 | * lru_cache_add_lru - add a page to a page list | |
313 | * @page: the page to be added to the LRU. | |
314 | * @lru: the LRU list to which the page is added. | |
315 | */ | |
316 | void lru_cache_add_lru(struct page *page, enum lru_list lru) | |
1da177e4 | 317 | { |
f04e9ebb | 318 | if (PageActive(page)) { |
894bc310 | 319 | VM_BUG_ON(PageUnevictable(page)); |
f04e9ebb | 320 | ClearPageActive(page); |
894bc310 LS |
321 | } else if (PageUnevictable(page)) { |
322 | VM_BUG_ON(PageActive(page)); | |
323 | ClearPageUnevictable(page); | |
f04e9ebb | 324 | } |
1da177e4 | 325 | |
894bc310 | 326 | VM_BUG_ON(PageLRU(page) || PageActive(page) || PageUnevictable(page)); |
f04e9ebb | 327 | __lru_cache_add(page, lru); |
1da177e4 LT |
328 | } |
329 | ||
894bc310 LS |
330 | /** |
331 | * add_page_to_unevictable_list - add a page to the unevictable list | |
332 | * @page: the page to be added to the unevictable list | |
333 | * | |
334 | * Add page directly to its zone's unevictable list. To avoid races with | |
335 | * tasks that might be making the page evictable, through eg. munlock, | |
336 | * munmap or exit, while it's not on the lru, we want to add the page | |
337 | * while it's locked or otherwise "invisible" to other tasks. This is | |
338 | * difficult to do when using the pagevec cache, so bypass that. | |
339 | */ | |
340 | void add_page_to_unevictable_list(struct page *page) | |
341 | { | |
342 | struct zone *zone = page_zone(page); | |
343 | ||
344 | spin_lock_irq(&zone->lru_lock); | |
345 | SetPageUnevictable(page); | |
346 | SetPageLRU(page); | |
347 | add_page_to_lru_list(zone, page, LRU_UNEVICTABLE); | |
348 | spin_unlock_irq(&zone->lru_lock); | |
349 | } | |
350 | ||
31560180 MK |
351 | /* |
352 | * If the page can not be invalidated, it is moved to the | |
353 | * inactive list to speed up its reclaim. It is moved to the | |
354 | * head of the list, rather than the tail, to give the flusher | |
355 | * threads some time to write it out, as this is much more | |
356 | * effective than the single-page writeout from reclaim. | |
278df9f4 MK |
357 | * |
358 | * If the page isn't page_mapped and dirty/writeback, the page | |
359 | * could reclaim asap using PG_reclaim. | |
360 | * | |
361 | * 1. active, mapped page -> none | |
362 | * 2. active, dirty/writeback page -> inactive, head, PG_reclaim | |
363 | * 3. inactive, mapped page -> none | |
364 | * 4. inactive, dirty/writeback page -> inactive, head, PG_reclaim | |
365 | * 5. inactive, clean -> inactive, tail | |
366 | * 6. Others -> none | |
367 | * | |
368 | * In 4, why it moves inactive's head, the VM expects the page would | |
369 | * be write it out by flusher threads as this is much more effective | |
370 | * than the single-page writeout from reclaim. | |
31560180 MK |
371 | */ |
372 | static void lru_deactivate(struct page *page, struct zone *zone) | |
373 | { | |
374 | int lru, file; | |
278df9f4 | 375 | bool active; |
31560180 | 376 | |
278df9f4 | 377 | if (!PageLRU(page)) |
31560180 MK |
378 | return; |
379 | ||
380 | /* Some processes are using the page */ | |
381 | if (page_mapped(page)) | |
382 | return; | |
383 | ||
278df9f4 MK |
384 | active = PageActive(page); |
385 | ||
31560180 MK |
386 | file = page_is_file_cache(page); |
387 | lru = page_lru_base_type(page); | |
278df9f4 | 388 | del_page_from_lru_list(zone, page, lru + active); |
31560180 MK |
389 | ClearPageActive(page); |
390 | ClearPageReferenced(page); | |
391 | add_page_to_lru_list(zone, page, lru); | |
31560180 | 392 | |
278df9f4 MK |
393 | if (PageWriteback(page) || PageDirty(page)) { |
394 | /* | |
395 | * PG_reclaim could be raced with end_page_writeback | |
396 | * It can make readahead confusing. But race window | |
397 | * is _really_ small and it's non-critical problem. | |
398 | */ | |
399 | SetPageReclaim(page); | |
400 | } else { | |
401 | /* | |
402 | * The page's writeback ends up during pagevec | |
403 | * We moves tha page into tail of inactive. | |
404 | */ | |
405 | list_move_tail(&page->lru, &zone->lru[lru].list); | |
406 | mem_cgroup_rotate_reclaimable_page(page); | |
407 | __count_vm_event(PGROTATED); | |
408 | } | |
409 | ||
410 | if (active) | |
411 | __count_vm_event(PGDEACTIVATE); | |
31560180 MK |
412 | update_page_reclaim_stat(zone, page, file, 0); |
413 | } | |
414 | ||
415 | static void ____pagevec_lru_deactivate(struct pagevec *pvec) | |
416 | { | |
417 | int i; | |
418 | struct zone *zone = NULL; | |
419 | ||
420 | for (i = 0; i < pagevec_count(pvec); i++) { | |
421 | struct page *page = pvec->pages[i]; | |
422 | struct zone *pagezone = page_zone(page); | |
423 | ||
424 | if (pagezone != zone) { | |
425 | if (zone) | |
426 | spin_unlock_irq(&zone->lru_lock); | |
427 | zone = pagezone; | |
428 | spin_lock_irq(&zone->lru_lock); | |
429 | } | |
430 | lru_deactivate(page, zone); | |
431 | } | |
432 | if (zone) | |
433 | spin_unlock_irq(&zone->lru_lock); | |
434 | ||
435 | release_pages(pvec->pages, pvec->nr, pvec->cold); | |
436 | pagevec_reinit(pvec); | |
437 | } | |
438 | ||
439 | ||
902aaed0 HH |
440 | /* |
441 | * Drain pages out of the cpu's pagevecs. | |
442 | * Either "cpu" is the current CPU, and preemption has already been | |
443 | * disabled; or "cpu" is being hot-unplugged, and is already dead. | |
444 | */ | |
445 | static void drain_cpu_pagevecs(int cpu) | |
1da177e4 | 446 | { |
f04e9ebb | 447 | struct pagevec *pvecs = per_cpu(lru_add_pvecs, cpu); |
902aaed0 | 448 | struct pagevec *pvec; |
f04e9ebb | 449 | int lru; |
1da177e4 | 450 | |
f04e9ebb KM |
451 | for_each_lru(lru) { |
452 | pvec = &pvecs[lru - LRU_BASE]; | |
453 | if (pagevec_count(pvec)) | |
454 | ____pagevec_lru_add(pvec, lru); | |
455 | } | |
902aaed0 HH |
456 | |
457 | pvec = &per_cpu(lru_rotate_pvecs, cpu); | |
458 | if (pagevec_count(pvec)) { | |
459 | unsigned long flags; | |
460 | ||
461 | /* No harm done if a racing interrupt already did this */ | |
462 | local_irq_save(flags); | |
463 | pagevec_move_tail(pvec); | |
464 | local_irq_restore(flags); | |
465 | } | |
31560180 MK |
466 | |
467 | pvec = &per_cpu(lru_deactivate_pvecs, cpu); | |
468 | if (pagevec_count(pvec)) | |
469 | ____pagevec_lru_deactivate(pvec); | |
470 | } | |
471 | ||
472 | /** | |
473 | * deactivate_page - forcefully deactivate a page | |
474 | * @page: page to deactivate | |
475 | * | |
476 | * This function hints the VM that @page is a good reclaim candidate, | |
477 | * for example if its invalidation fails due to the page being dirty | |
478 | * or under writeback. | |
479 | */ | |
480 | void deactivate_page(struct page *page) | |
481 | { | |
482 | if (likely(get_page_unless_zero(page))) { | |
483 | struct pagevec *pvec = &get_cpu_var(lru_deactivate_pvecs); | |
484 | ||
485 | if (!pagevec_add(pvec, page)) | |
486 | ____pagevec_lru_deactivate(pvec); | |
487 | put_cpu_var(lru_deactivate_pvecs); | |
488 | } | |
80bfed90 AM |
489 | } |
490 | ||
491 | void lru_add_drain(void) | |
492 | { | |
902aaed0 | 493 | drain_cpu_pagevecs(get_cpu()); |
80bfed90 | 494 | put_cpu(); |
1da177e4 LT |
495 | } |
496 | ||
c4028958 | 497 | static void lru_add_drain_per_cpu(struct work_struct *dummy) |
053837fc NP |
498 | { |
499 | lru_add_drain(); | |
500 | } | |
501 | ||
502 | /* | |
503 | * Returns 0 for success | |
504 | */ | |
505 | int lru_add_drain_all(void) | |
506 | { | |
c4028958 | 507 | return schedule_on_each_cpu(lru_add_drain_per_cpu); |
053837fc NP |
508 | } |
509 | ||
1da177e4 LT |
510 | /* |
511 | * Batched page_cache_release(). Decrement the reference count on all the | |
512 | * passed pages. If it fell to zero then remove the page from the LRU and | |
513 | * free it. | |
514 | * | |
515 | * Avoid taking zone->lru_lock if possible, but if it is taken, retain it | |
516 | * for the remainder of the operation. | |
517 | * | |
ab33dc09 FLVC |
518 | * The locking in this function is against shrink_inactive_list(): we recheck |
519 | * the page count inside the lock to see whether shrink_inactive_list() | |
520 | * grabbed the page via the LRU. If it did, give up: shrink_inactive_list() | |
521 | * will free it. | |
1da177e4 LT |
522 | */ |
523 | void release_pages(struct page **pages, int nr, int cold) | |
524 | { | |
525 | int i; | |
526 | struct pagevec pages_to_free; | |
527 | struct zone *zone = NULL; | |
902aaed0 | 528 | unsigned long uninitialized_var(flags); |
1da177e4 LT |
529 | |
530 | pagevec_init(&pages_to_free, cold); | |
531 | for (i = 0; i < nr; i++) { | |
532 | struct page *page = pages[i]; | |
1da177e4 | 533 | |
8519fb30 NP |
534 | if (unlikely(PageCompound(page))) { |
535 | if (zone) { | |
902aaed0 | 536 | spin_unlock_irqrestore(&zone->lru_lock, flags); |
8519fb30 NP |
537 | zone = NULL; |
538 | } | |
539 | put_compound_page(page); | |
540 | continue; | |
541 | } | |
542 | ||
b5810039 | 543 | if (!put_page_testzero(page)) |
1da177e4 LT |
544 | continue; |
545 | ||
46453a6e NP |
546 | if (PageLRU(page)) { |
547 | struct zone *pagezone = page_zone(page); | |
894bc310 | 548 | |
46453a6e NP |
549 | if (pagezone != zone) { |
550 | if (zone) | |
902aaed0 HH |
551 | spin_unlock_irqrestore(&zone->lru_lock, |
552 | flags); | |
46453a6e | 553 | zone = pagezone; |
902aaed0 | 554 | spin_lock_irqsave(&zone->lru_lock, flags); |
46453a6e | 555 | } |
725d704e | 556 | VM_BUG_ON(!PageLRU(page)); |
67453911 | 557 | __ClearPageLRU(page); |
1da177e4 | 558 | del_page_from_lru(zone, page); |
46453a6e NP |
559 | } |
560 | ||
561 | if (!pagevec_add(&pages_to_free, page)) { | |
562 | if (zone) { | |
902aaed0 | 563 | spin_unlock_irqrestore(&zone->lru_lock, flags); |
46453a6e | 564 | zone = NULL; |
1da177e4 | 565 | } |
46453a6e NP |
566 | __pagevec_free(&pages_to_free); |
567 | pagevec_reinit(&pages_to_free); | |
568 | } | |
1da177e4 LT |
569 | } |
570 | if (zone) | |
902aaed0 | 571 | spin_unlock_irqrestore(&zone->lru_lock, flags); |
1da177e4 LT |
572 | |
573 | pagevec_free(&pages_to_free); | |
574 | } | |
0be8557b | 575 | EXPORT_SYMBOL(release_pages); |
1da177e4 LT |
576 | |
577 | /* | |
578 | * The pages which we're about to release may be in the deferred lru-addition | |
579 | * queues. That would prevent them from really being freed right now. That's | |
580 | * OK from a correctness point of view but is inefficient - those pages may be | |
581 | * cache-warm and we want to give them back to the page allocator ASAP. | |
582 | * | |
583 | * So __pagevec_release() will drain those queues here. __pagevec_lru_add() | |
584 | * and __pagevec_lru_add_active() call release_pages() directly to avoid | |
585 | * mutual recursion. | |
586 | */ | |
587 | void __pagevec_release(struct pagevec *pvec) | |
588 | { | |
589 | lru_add_drain(); | |
590 | release_pages(pvec->pages, pagevec_count(pvec), pvec->cold); | |
591 | pagevec_reinit(pvec); | |
592 | } | |
593 | ||
7f285701 SF |
594 | EXPORT_SYMBOL(__pagevec_release); |
595 | ||
71e3aac0 AA |
596 | /* used by __split_huge_page_refcount() */ |
597 | void lru_add_page_tail(struct zone* zone, | |
598 | struct page *page, struct page *page_tail) | |
599 | { | |
600 | int active; | |
601 | enum lru_list lru; | |
602 | const int file = 0; | |
603 | struct list_head *head; | |
604 | ||
605 | VM_BUG_ON(!PageHead(page)); | |
606 | VM_BUG_ON(PageCompound(page_tail)); | |
607 | VM_BUG_ON(PageLRU(page_tail)); | |
608 | VM_BUG_ON(!spin_is_locked(&zone->lru_lock)); | |
609 | ||
610 | SetPageLRU(page_tail); | |
611 | ||
612 | if (page_evictable(page_tail, NULL)) { | |
613 | if (PageActive(page)) { | |
614 | SetPageActive(page_tail); | |
615 | active = 1; | |
616 | lru = LRU_ACTIVE_ANON; | |
617 | } else { | |
618 | active = 0; | |
619 | lru = LRU_INACTIVE_ANON; | |
620 | } | |
621 | update_page_reclaim_stat(zone, page_tail, file, active); | |
622 | if (likely(PageLRU(page))) | |
623 | head = page->lru.prev; | |
624 | else | |
625 | head = &zone->lru[lru].list; | |
626 | __add_page_to_lru_list(zone, page_tail, lru, head); | |
627 | } else { | |
628 | SetPageUnevictable(page_tail); | |
629 | add_page_to_lru_list(zone, page_tail, LRU_UNEVICTABLE); | |
630 | } | |
631 | } | |
632 | ||
1da177e4 LT |
633 | /* |
634 | * Add the passed pages to the LRU, then drop the caller's refcount | |
635 | * on them. Reinitialises the caller's pagevec. | |
636 | */ | |
f04e9ebb | 637 | void ____pagevec_lru_add(struct pagevec *pvec, enum lru_list lru) |
1da177e4 | 638 | { |
83896fb5 LT |
639 | int i; |
640 | struct zone *zone = NULL; | |
641 | ||
894bc310 | 642 | VM_BUG_ON(is_unevictable_lru(lru)); |
1da177e4 | 643 | |
83896fb5 LT |
644 | for (i = 0; i < pagevec_count(pvec); i++) { |
645 | struct page *page = pvec->pages[i]; | |
646 | struct zone *pagezone = page_zone(page); | |
647 | int file; | |
648 | int active; | |
649 | ||
650 | if (pagezone != zone) { | |
651 | if (zone) | |
652 | spin_unlock_irq(&zone->lru_lock); | |
653 | zone = pagezone; | |
654 | spin_lock_irq(&zone->lru_lock); | |
655 | } | |
656 | VM_BUG_ON(PageActive(page)); | |
657 | VM_BUG_ON(PageUnevictable(page)); | |
658 | VM_BUG_ON(PageLRU(page)); | |
659 | SetPageLRU(page); | |
660 | active = is_active_lru(lru); | |
661 | file = is_file_lru(lru); | |
662 | if (active) | |
663 | SetPageActive(page); | |
664 | update_page_reclaim_stat(zone, page, file, active); | |
665 | add_page_to_lru_list(zone, page, lru); | |
666 | } | |
667 | if (zone) | |
668 | spin_unlock_irq(&zone->lru_lock); | |
669 | release_pages(pvec->pages, pvec->nr, pvec->cold); | |
670 | pagevec_reinit(pvec); | |
1da177e4 LT |
671 | } |
672 | ||
f04e9ebb | 673 | EXPORT_SYMBOL(____pagevec_lru_add); |
1da177e4 LT |
674 | |
675 | /* | |
676 | * Try to drop buffers from the pages in a pagevec | |
677 | */ | |
678 | void pagevec_strip(struct pagevec *pvec) | |
679 | { | |
680 | int i; | |
681 | ||
682 | for (i = 0; i < pagevec_count(pvec); i++) { | |
683 | struct page *page = pvec->pages[i]; | |
684 | ||
266cf658 DH |
685 | if (page_has_private(page) && trylock_page(page)) { |
686 | if (page_has_private(page)) | |
5b40dc78 | 687 | try_to_release_page(page, 0); |
1da177e4 LT |
688 | unlock_page(page); |
689 | } | |
690 | } | |
691 | } | |
692 | ||
693 | /** | |
694 | * pagevec_lookup - gang pagecache lookup | |
695 | * @pvec: Where the resulting pages are placed | |
696 | * @mapping: The address_space to search | |
697 | * @start: The starting page index | |
698 | * @nr_pages: The maximum number of pages | |
699 | * | |
700 | * pagevec_lookup() will search for and return a group of up to @nr_pages pages | |
701 | * in the mapping. The pages are placed in @pvec. pagevec_lookup() takes a | |
702 | * reference against the pages in @pvec. | |
703 | * | |
704 | * The search returns a group of mapping-contiguous pages with ascending | |
705 | * indexes. There may be holes in the indices due to not-present pages. | |
706 | * | |
707 | * pagevec_lookup() returns the number of pages which were found. | |
708 | */ | |
709 | unsigned pagevec_lookup(struct pagevec *pvec, struct address_space *mapping, | |
710 | pgoff_t start, unsigned nr_pages) | |
711 | { | |
712 | pvec->nr = find_get_pages(mapping, start, nr_pages, pvec->pages); | |
713 | return pagevec_count(pvec); | |
714 | } | |
715 | ||
78539fdf CH |
716 | EXPORT_SYMBOL(pagevec_lookup); |
717 | ||
1da177e4 LT |
718 | unsigned pagevec_lookup_tag(struct pagevec *pvec, struct address_space *mapping, |
719 | pgoff_t *index, int tag, unsigned nr_pages) | |
720 | { | |
721 | pvec->nr = find_get_pages_tag(mapping, index, tag, | |
722 | nr_pages, pvec->pages); | |
723 | return pagevec_count(pvec); | |
724 | } | |
725 | ||
7f285701 | 726 | EXPORT_SYMBOL(pagevec_lookup_tag); |
1da177e4 | 727 | |
1da177e4 LT |
728 | /* |
729 | * Perform any setup for the swap system | |
730 | */ | |
731 | void __init swap_setup(void) | |
732 | { | |
4481374c | 733 | unsigned long megs = totalram_pages >> (20 - PAGE_SHIFT); |
1da177e4 | 734 | |
e0bf68dd PZ |
735 | #ifdef CONFIG_SWAP |
736 | bdi_init(swapper_space.backing_dev_info); | |
737 | #endif | |
738 | ||
1da177e4 LT |
739 | /* Use a smaller cluster for small-memory machines */ |
740 | if (megs < 16) | |
741 | page_cluster = 2; | |
742 | else | |
743 | page_cluster = 3; | |
744 | /* | |
745 | * Right now other parts of the system means that we | |
746 | * _really_ don't want to cluster much more | |
747 | */ | |
1da177e4 | 748 | } |