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Source at commit b386be689295730688885552666ea40b2e639b14 created 11 years 11 months ago. By Maarten ter Huurne, Revert "MIPS: JZ4740: reset: Initialize hibernate wakeup counters." | |
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1 | /* |
2 | * linux/mm/swap.c |
3 | * |
4 | * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds |
5 | */ |
6 | |
7 | /* |
8 | * This file contains the default values for the operation of the |
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/export.h> |
25 | #include <linux/mm_inline.h> |
26 | #include <linux/percpu_counter.h> |
27 | #include <linux/percpu.h> |
28 | #include <linux/cpu.h> |
29 | #include <linux/notifier.h> |
30 | #include <linux/backing-dev.h> |
31 | #include <linux/memcontrol.h> |
32 | #include <linux/gfp.h> |
33 | |
34 | #include "internal.h" |
35 | |
36 | /* How many pages do we try to swap or page in/out together? */ |
37 | int page_cluster; |
38 | |
39 | static DEFINE_PER_CPU(struct pagevec[NR_LRU_LISTS], lru_add_pvecs); |
40 | static DEFINE_PER_CPU(struct pagevec, lru_rotate_pvecs); |
41 | static DEFINE_PER_CPU(struct pagevec, lru_deactivate_pvecs); |
42 | |
43 | /* |
44 | * This path almost never happens for VM activity - pages are normally |
45 | * freed via pagevecs. But it gets used by networking. |
46 | */ |
47 | static void __page_cache_release(struct page *page) |
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_list(zone, page, page_off_lru(page)); |
57 | spin_unlock_irqrestore(&zone->lru_lock, flags); |
58 | } |
59 | } |
60 | |
61 | static void __put_single_page(struct page *page) |
62 | { |
63 | __page_cache_release(page); |
64 | free_hot_cold_page(page, 0); |
65 | } |
66 | |
67 | static void __put_compound_page(struct page *page) |
68 | { |
69 | compound_page_dtor *dtor; |
70 | |
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 */ |
80 | struct page *page_head = compound_trans_head(page); |
81 | |
82 | if (likely(page != page_head && |
83 | get_page_unless_zero(page_head))) { |
84 | unsigned long flags; |
85 | /* |
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. |
90 | */ |
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)); |
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 |
106 | * get_page_unless_zero() now that |
107 | * __split_huge_page_refcount() is blocked on |
108 | * the compound_lock. |
109 | */ |
110 | if (put_page_testzero(page_head)) |
111 | VM_BUG_ON(1); |
112 | /* __split_huge_page_refcount will wait now */ |
113 | VM_BUG_ON(page_mapcount(page) <= 0); |
114 | atomic_dec(&page->_mapcount); |
115 | VM_BUG_ON(atomic_read(&page_head->_count) <= 0); |
116 | VM_BUG_ON(atomic_read(&page->_count) != 0); |
117 | compound_unlock_irqrestore(page_head, flags); |
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 | } |
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); |
134 | } |
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)) |
142 | __put_single_page(page); |
143 | } |
144 | EXPORT_SYMBOL(put_page); |
145 | |
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 | |
185 | /** |
186 | * put_pages_list() - release a list of pages |
187 | * @pages: list of pages threaded on page->lru |
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. |
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 | |
204 | static void pagevec_lru_move_fn(struct pagevec *pvec, |
205 | void (*move_fn)(struct page *page, void *arg), |
206 | void *arg) |
207 | { |
208 | int i; |
209 | struct zone *zone = NULL; |
210 | unsigned long flags = 0; |
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) |
218 | spin_unlock_irqrestore(&zone->lru_lock, flags); |
219 | zone = pagezone; |
220 | spin_lock_irqsave(&zone->lru_lock, flags); |
221 | } |
222 | |
223 | (*move_fn)(page, arg); |
224 | } |
225 | if (zone) |
226 | spin_unlock_irqrestore(&zone->lru_lock, flags); |
227 | release_pages(pvec->pages, pvec->nr, pvec->cold); |
228 | pagevec_reinit(pvec); |
229 | } |
230 | |
231 | static void pagevec_move_tail_fn(struct page *page, void *arg) |
232 | { |
233 | int *pgmoved = arg; |
234 | |
235 | if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) { |
236 | enum lru_list lru = page_lru_base_type(page); |
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]); |
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 | |
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 |
261 | * inactive list. |
262 | */ |
263 | void rotate_reclaimable_page(struct page *page) |
264 | { |
265 | if (!PageLocked(page) && !PageDirty(page) && !PageActive(page) && |
266 | !PageUnevictable(page) && PageLRU(page)) { |
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 | } |
277 | } |
278 | |
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 | |
299 | static void __activate_page(struct page *page, void *arg) |
300 | { |
301 | struct zone *zone = page_zone(page); |
302 | |
303 | if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) { |
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); |
307 | |
308 | SetPageActive(page); |
309 | lru += LRU_ACTIVE; |
310 | add_page_to_lru_list(zone, page, lru); |
311 | __count_vm_event(PGACTIVATE); |
312 | |
313 | update_page_reclaim_stat(zone, page, file, 1); |
314 | } |
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); |
351 | spin_unlock_irq(&zone->lru_lock); |
352 | } |
353 | #endif |
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 | */ |
362 | void mark_page_accessed(struct page *page) |
363 | { |
364 | if (!PageActive(page) && !PageUnevictable(page) && |
365 | PageReferenced(page) && PageLRU(page)) { |
366 | activate_page(page); |
367 | ClearPageReferenced(page); |
368 | } else if (!PageReferenced(page)) { |
369 | SetPageReferenced(page); |
370 | } |
371 | } |
372 | EXPORT_SYMBOL(mark_page_accessed); |
373 | |
374 | void __lru_cache_add(struct page *page, enum lru_list lru) |
375 | { |
376 | struct pagevec *pvec = &get_cpu_var(lru_add_pvecs)[lru]; |
377 | |
378 | page_cache_get(page); |
379 | if (!pagevec_add(pvec, page)) |
380 | __pagevec_lru_add(pvec, lru); |
381 | put_cpu_var(lru_add_pvecs); |
382 | } |
383 | EXPORT_SYMBOL(__lru_cache_add); |
384 | |
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) |
391 | { |
392 | if (PageActive(page)) { |
393 | VM_BUG_ON(PageUnevictable(page)); |
394 | ClearPageActive(page); |
395 | } else if (PageUnevictable(page)) { |
396 | VM_BUG_ON(PageActive(page)); |
397 | ClearPageUnevictable(page); |
398 | } |
399 | |
400 | VM_BUG_ON(PageLRU(page) || PageActive(page) || PageUnevictable(page)); |
401 | __lru_cache_add(page, lru); |
402 | } |
403 | |
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 | |
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. |
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. |
445 | */ |
446 | static void lru_deactivate_fn(struct page *page, void *arg) |
447 | { |
448 | int lru, file; |
449 | bool active; |
450 | struct zone *zone = page_zone(page); |
451 | |
452 | if (!PageLRU(page)) |
453 | return; |
454 | |
455 | if (PageUnevictable(page)) |
456 | return; |
457 | |
458 | /* Some processes are using the page */ |
459 | if (page_mapped(page)) |
460 | return; |
461 | |
462 | active = PageActive(page); |
463 | |
464 | file = page_is_file_cache(page); |
465 | lru = page_lru_base_type(page); |
466 | del_page_from_lru_list(zone, page, lru + active); |
467 | ClearPageActive(page); |
468 | ClearPageReferenced(page); |
469 | add_page_to_lru_list(zone, page, lru); |
470 | |
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 | struct lruvec *lruvec; |
480 | /* |
481 | * The page's writeback ends up during pagevec |
482 | * We moves tha page into tail of inactive. |
483 | */ |
484 | lruvec = mem_cgroup_lru_move_lists(zone, page, lru, lru); |
485 | list_move_tail(&page->lru, &lruvec->lists[lru]); |
486 | __count_vm_event(PGROTATED); |
487 | } |
488 | |
489 | if (active) |
490 | __count_vm_event(PGDEACTIVATE); |
491 | update_page_reclaim_stat(zone, page, file, 0); |
492 | } |
493 | |
494 | /* |
495 | * Drain pages out of the cpu's pagevecs. |
496 | * Either "cpu" is the current CPU, and preemption has already been |
497 | * disabled; or "cpu" is being hot-unplugged, and is already dead. |
498 | */ |
499 | static void drain_cpu_pagevecs(int cpu) |
500 | { |
501 | struct pagevec *pvecs = per_cpu(lru_add_pvecs, cpu); |
502 | struct pagevec *pvec; |
503 | int lru; |
504 | |
505 | for_each_lru(lru) { |
506 | pvec = &pvecs[lru - LRU_BASE]; |
507 | if (pagevec_count(pvec)) |
508 | __pagevec_lru_add(pvec, lru); |
509 | } |
510 | |
511 | pvec = &per_cpu(lru_rotate_pvecs, cpu); |
512 | if (pagevec_count(pvec)) { |
513 | unsigned long flags; |
514 | |
515 | /* No harm done if a racing interrupt already did this */ |
516 | local_irq_save(flags); |
517 | pagevec_move_tail(pvec); |
518 | local_irq_restore(flags); |
519 | } |
520 | |
521 | pvec = &per_cpu(lru_deactivate_pvecs, cpu); |
522 | if (pagevec_count(pvec)) |
523 | pagevec_lru_move_fn(pvec, lru_deactivate_fn, NULL); |
524 | |
525 | activate_page_drain(cpu); |
526 | } |
527 | |
528 | /** |
529 | * deactivate_page - forcefully deactivate a page |
530 | * @page: page to deactivate |
531 | * |
532 | * This function hints the VM that @page is a good reclaim candidate, |
533 | * for example if its invalidation fails due to the page being dirty |
534 | * or under writeback. |
535 | */ |
536 | void deactivate_page(struct page *page) |
537 | { |
538 | /* |
539 | * In a workload with many unevictable page such as mprotect, unevictable |
540 | * page deactivation for accelerating reclaim is pointless. |
541 | */ |
542 | if (PageUnevictable(page)) |
543 | return; |
544 | |
545 | if (likely(get_page_unless_zero(page))) { |
546 | struct pagevec *pvec = &get_cpu_var(lru_deactivate_pvecs); |
547 | |
548 | if (!pagevec_add(pvec, page)) |
549 | pagevec_lru_move_fn(pvec, lru_deactivate_fn, NULL); |
550 | put_cpu_var(lru_deactivate_pvecs); |
551 | } |
552 | } |
553 | |
554 | void lru_add_drain(void) |
555 | { |
556 | drain_cpu_pagevecs(get_cpu()); |
557 | put_cpu(); |
558 | } |
559 | |
560 | static void lru_add_drain_per_cpu(struct work_struct *dummy) |
561 | { |
562 | lru_add_drain(); |
563 | } |
564 | |
565 | /* |
566 | * Returns 0 for success |
567 | */ |
568 | int lru_add_drain_all(void) |
569 | { |
570 | return schedule_on_each_cpu(lru_add_drain_per_cpu); |
571 | } |
572 | |
573 | /* |
574 | * Batched page_cache_release(). Decrement the reference count on all the |
575 | * passed pages. If it fell to zero then remove the page from the LRU and |
576 | * free it. |
577 | * |
578 | * Avoid taking zone->lru_lock if possible, but if it is taken, retain it |
579 | * for the remainder of the operation. |
580 | * |
581 | * The locking in this function is against shrink_inactive_list(): we recheck |
582 | * the page count inside the lock to see whether shrink_inactive_list() |
583 | * grabbed the page via the LRU. If it did, give up: shrink_inactive_list() |
584 | * will free it. |
585 | */ |
586 | void release_pages(struct page **pages, int nr, int cold) |
587 | { |
588 | int i; |
589 | LIST_HEAD(pages_to_free); |
590 | struct zone *zone = NULL; |
591 | unsigned long uninitialized_var(flags); |
592 | |
593 | for (i = 0; i < nr; i++) { |
594 | struct page *page = pages[i]; |
595 | |
596 | if (unlikely(PageCompound(page))) { |
597 | if (zone) { |
598 | spin_unlock_irqrestore(&zone->lru_lock, flags); |
599 | zone = NULL; |
600 | } |
601 | put_compound_page(page); |
602 | continue; |
603 | } |
604 | |
605 | if (!put_page_testzero(page)) |
606 | continue; |
607 | |
608 | if (PageLRU(page)) { |
609 | struct zone *pagezone = page_zone(page); |
610 | |
611 | if (pagezone != zone) { |
612 | if (zone) |
613 | spin_unlock_irqrestore(&zone->lru_lock, |
614 | flags); |
615 | zone = pagezone; |
616 | spin_lock_irqsave(&zone->lru_lock, flags); |
617 | } |
618 | VM_BUG_ON(!PageLRU(page)); |
619 | __ClearPageLRU(page); |
620 | del_page_from_lru_list(zone, page, page_off_lru(page)); |
621 | } |
622 | |
623 | list_add(&page->lru, &pages_to_free); |
624 | } |
625 | if (zone) |
626 | spin_unlock_irqrestore(&zone->lru_lock, flags); |
627 | |
628 | free_hot_cold_page_list(&pages_to_free, cold); |
629 | } |
630 | EXPORT_SYMBOL(release_pages); |
631 | |
632 | /* |
633 | * The pages which we're about to release may be in the deferred lru-addition |
634 | * queues. That would prevent them from really being freed right now. That's |
635 | * OK from a correctness point of view but is inefficient - those pages may be |
636 | * cache-warm and we want to give them back to the page allocator ASAP. |
637 | * |
638 | * So __pagevec_release() will drain those queues here. __pagevec_lru_add() |
639 | * and __pagevec_lru_add_active() call release_pages() directly to avoid |
640 | * mutual recursion. |
641 | */ |
642 | void __pagevec_release(struct pagevec *pvec) |
643 | { |
644 | lru_add_drain(); |
645 | release_pages(pvec->pages, pagevec_count(pvec), pvec->cold); |
646 | pagevec_reinit(pvec); |
647 | } |
648 | EXPORT_SYMBOL(__pagevec_release); |
649 | |
650 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE |
651 | /* used by __split_huge_page_refcount() */ |
652 | void lru_add_page_tail(struct zone* zone, |
653 | struct page *page, struct page *page_tail) |
654 | { |
655 | int uninitialized_var(active); |
656 | enum lru_list lru; |
657 | const int file = 0; |
658 | |
659 | VM_BUG_ON(!PageHead(page)); |
660 | VM_BUG_ON(PageCompound(page_tail)); |
661 | VM_BUG_ON(PageLRU(page_tail)); |
662 | VM_BUG_ON(NR_CPUS != 1 && !spin_is_locked(&zone->lru_lock)); |
663 | |
664 | SetPageLRU(page_tail); |
665 | |
666 | if (page_evictable(page_tail, NULL)) { |
667 | if (PageActive(page)) { |
668 | SetPageActive(page_tail); |
669 | active = 1; |
670 | lru = LRU_ACTIVE_ANON; |
671 | } else { |
672 | active = 0; |
673 | lru = LRU_INACTIVE_ANON; |
674 | } |
675 | } else { |
676 | SetPageUnevictable(page_tail); |
677 | lru = LRU_UNEVICTABLE; |
678 | } |
679 | |
680 | if (likely(PageLRU(page))) |
681 | list_add_tail(&page_tail->lru, &page->lru); |
682 | else { |
683 | struct list_head *list_head; |
684 | /* |
685 | * Head page has not yet been counted, as an hpage, |
686 | * so we must account for each subpage individually. |
687 | * |
688 | * Use the standard add function to put page_tail on the list, |
689 | * but then correct its position so they all end up in order. |
690 | */ |
691 | add_page_to_lru_list(zone, page_tail, lru); |
692 | list_head = page_tail->lru.prev; |
693 | list_move_tail(&page_tail->lru, list_head); |
694 | } |
695 | |
696 | if (!PageUnevictable(page)) |
697 | update_page_reclaim_stat(zone, page_tail, file, active); |
698 | } |
699 | #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ |
700 | |
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 | add_page_to_lru_list(zone, page, lru); |
716 | update_page_reclaim_stat(zone, page, file, active); |
717 | } |
718 | |
719 | /* |
720 | * Add the passed pages to the LRU, then drop the caller's refcount |
721 | * on them. Reinitialises the caller's pagevec. |
722 | */ |
723 | void __pagevec_lru_add(struct pagevec *pvec, enum lru_list lru) |
724 | { |
725 | VM_BUG_ON(is_unevictable_lru(lru)); |
726 | |
727 | pagevec_lru_move_fn(pvec, __pagevec_lru_add_fn, (void *)lru); |
728 | } |
729 | EXPORT_SYMBOL(__pagevec_lru_add); |
730 | |
731 | /** |
732 | * pagevec_lookup - gang pagecache lookup |
733 | * @pvec: Where the resulting pages are placed |
734 | * @mapping: The address_space to search |
735 | * @start: The starting page index |
736 | * @nr_pages: The maximum number of pages |
737 | * |
738 | * pagevec_lookup() will search for and return a group of up to @nr_pages pages |
739 | * in the mapping. The pages are placed in @pvec. pagevec_lookup() takes a |
740 | * reference against the pages in @pvec. |
741 | * |
742 | * The search returns a group of mapping-contiguous pages with ascending |
743 | * indexes. There may be holes in the indices due to not-present pages. |
744 | * |
745 | * pagevec_lookup() returns the number of pages which were found. |
746 | */ |
747 | unsigned pagevec_lookup(struct pagevec *pvec, struct address_space *mapping, |
748 | pgoff_t start, unsigned nr_pages) |
749 | { |
750 | pvec->nr = find_get_pages(mapping, start, nr_pages, pvec->pages); |
751 | return pagevec_count(pvec); |
752 | } |
753 | EXPORT_SYMBOL(pagevec_lookup); |
754 | |
755 | unsigned pagevec_lookup_tag(struct pagevec *pvec, struct address_space *mapping, |
756 | pgoff_t *index, int tag, unsigned nr_pages) |
757 | { |
758 | pvec->nr = find_get_pages_tag(mapping, index, tag, |
759 | nr_pages, pvec->pages); |
760 | return pagevec_count(pvec); |
761 | } |
762 | EXPORT_SYMBOL(pagevec_lookup_tag); |
763 | |
764 | /* |
765 | * Perform any setup for the swap system |
766 | */ |
767 | void __init swap_setup(void) |
768 | { |
769 | unsigned long megs = totalram_pages >> (20 - PAGE_SHIFT); |
770 | |
771 | #ifdef CONFIG_SWAP |
772 | bdi_init(swapper_space.backing_dev_info); |
773 | #endif |
774 | |
775 | /* Use a smaller cluster for small-memory machines */ |
776 | if (megs < 16) |
777 | page_cluster = 2; |
778 | else |
779 | page_cluster = 3; |
780 | /* |
781 | * Right now other parts of the system means that we |
782 | * _really_ don't want to cluster much more |
783 | */ |
784 | } |
785 |
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