blob: 4aea806d0d441c7d58d4bc8be83103ff743e5289 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/mm/swap.c
3 *
4 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
5 */
6
7/*
Simon Arlott183ff222007-10-20 01:27:18 +02008 * This file contains the default values for the operation of the
Linus Torvalds1da177e2005-04-16 15:20:36 -07009 * 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() */
Linus Torvalds1da177e2005-04-16 15:20:36 -070027#include <linux/percpu_counter.h>
28#include <linux/percpu.h>
29#include <linux/cpu.h>
30#include <linux/notifier.h>
Peter Zijlstrae0bf68d2007-10-16 23:25:46 -070031#include <linux/backing-dev.h>
Balbir Singh66e17072008-02-07 00:13:56 -080032#include <linux/memcontrol.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090033#include <linux/gfp.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070034
Lee Schermerhorn64d65192008-10-18 20:26:52 -070035#include "internal.h"
36
Linus Torvalds1da177e2005-04-16 15:20:36 -070037/* How many pages do we try to swap or page in/out together? */
38int page_cluster;
39
KOSAKI Motohirof04e9eb2008-10-18 20:26:19 -070040static DEFINE_PER_CPU(struct pagevec[NR_LRU_LISTS], lru_add_pvecs);
Vegard Nossumf84f95042008-07-23 21:28:14 -070041static DEFINE_PER_CPU(struct pagevec, lru_rotate_pvecs);
Minchan Kim31560182011-03-22 16:32:52 -070042static DEFINE_PER_CPU(struct pagevec, lru_deactivate_pvecs);
Hisashi Hifumi902aaed2007-10-16 01:24:52 -070043
Adrian Bunkb2213852006-09-25 23:31:02 -070044/*
45 * This path almost never happens for VM activity - pages are normally
46 * freed via pagevecs. But it gets used by networking.
47 */
Harvey Harrison920c7a52008-02-04 22:29:26 -080048static void __page_cache_release(struct page *page)
Adrian Bunkb2213852006-09-25 23:31:02 -070049{
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 }
Andrea Arcangeli91807062011-01-13 15:46:32 -080060}
61
62static void __put_single_page(struct page *page)
63{
64 __page_cache_release(page);
Li Hongfc916682010-03-05 13:41:54 -080065 free_hot_cold_page(page, 0);
Adrian Bunkb2213852006-09-25 23:31:02 -070066}
67
Andrea Arcangeli91807062011-01-13 15:46:32 -080068static void __put_compound_page(struct page *page)
69{
70 compound_page_dtor *dtor;
71
72 __page_cache_release(page);
73 dtor = get_compound_page_dtor(page);
74 (*dtor)(page);
75}
76
Nick Piggin8519fb32006-02-07 12:58:52 -080077static void put_compound_page(struct page *page)
78{
Andrea Arcangeli91807062011-01-13 15:46:32 -080079 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);
Andrea Arcangelia95a82e2011-01-13 15:46:33 -0800135 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 }
Andrea Arcangeli91807062011-01-13 15:46:32 -0800141 } 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);
Nick Piggin8519fb32006-02-07 12:58:52 -0800151 }
152}
153
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154void put_page(struct page *page)
155{
Nick Piggin8519fb32006-02-07 12:58:52 -0800156 if (unlikely(PageCompound(page)))
157 put_compound_page(page);
158 else if (put_page_testzero(page))
Andrea Arcangeli91807062011-01-13 15:46:32 -0800159 __put_single_page(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700160}
161EXPORT_SYMBOL(put_page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700162
Alexander Zarochentsev1d7ea732006-08-13 23:24:27 -0700163/**
Randy Dunlap76824862008-03-19 17:00:40 -0700164 * put_pages_list() - release a list of pages
165 * @pages: list of pages threaded on page->lru
Alexander Zarochentsev1d7ea732006-08-13 23:24:27 -0700166 *
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.
Alexander Zarochentsev1d7ea732006-08-13 23:24:27 -0700169 */
170void 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}
180EXPORT_SYMBOL(put_pages_list);
181
Linus Torvalds83896fb2011-01-17 14:42:34 -0800182/*
183 * pagevec_move_tail() must be called with IRQ disabled.
184 * Otherwise this may cause nasty races.
185 */
186static void pagevec_move_tail(struct pagevec *pvec)
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700187{
188 int i;
Linus Torvalds83896fb2011-01-17 14:42:34 -0800189 int pgmoved = 0;
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700190 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)
Linus Torvalds83896fb2011-01-17 14:42:34 -0800198 spin_unlock(&zone->lru_lock);
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700199 zone = pagezone;
Linus Torvalds83896fb2011-01-17 14:42:34 -0800200 spin_lock(&zone->lru_lock);
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700201 }
Linus Torvalds83896fb2011-01-17 14:42:34 -0800202 if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) {
203 int lru = page_lru_base_type(page);
204 list_move_tail(&page->lru, &zone->lru[lru].list);
205 pgmoved++;
206 }
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700207 }
208 if (zone)
Linus Torvalds83896fb2011-01-17 14:42:34 -0800209 spin_unlock(&zone->lru_lock);
Shaohua Lid8505de2011-01-13 15:47:33 -0800210 __count_vm_events(PGROTATED, pgmoved);
Linus Torvalds83896fb2011-01-17 14:42:34 -0800211 release_pages(pvec->pages, pvec->nr, pvec->cold);
212 pagevec_reinit(pvec);
Shaohua Lid8505de2011-01-13 15:47:33 -0800213}
214
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700215/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216 * Writeback is about to end against a page which has been marked for immediate
217 * reclaim. If it still appears to be reclaimable, move it to the tail of the
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700218 * inactive list.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700219 */
Linus Torvalds83896fb2011-01-17 14:42:34 -0800220void rotate_reclaimable_page(struct page *page)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700221{
Miklos Szerediac6aadb2008-04-28 02:12:38 -0700222 if (!PageLocked(page) && !PageDirty(page) && !PageActive(page) &&
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700223 !PageUnevictable(page) && PageLRU(page)) {
Miklos Szerediac6aadb2008-04-28 02:12:38 -0700224 struct pagevec *pvec;
225 unsigned long flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700226
Miklos Szerediac6aadb2008-04-28 02:12:38 -0700227 page_cache_get(page);
228 local_irq_save(flags);
229 pvec = &__get_cpu_var(lru_rotate_pvecs);
230 if (!pagevec_add(pvec, page))
231 pagevec_move_tail(pvec);
232 local_irq_restore(flags);
233 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700234}
235
KOSAKI Motohiro3e2f41f2009-01-07 18:08:20 -0800236static void update_page_reclaim_stat(struct zone *zone, struct page *page,
237 int file, int rotated)
238{
239 struct zone_reclaim_stat *reclaim_stat = &zone->reclaim_stat;
240 struct zone_reclaim_stat *memcg_reclaim_stat;
241
242 memcg_reclaim_stat = mem_cgroup_get_reclaim_stat_from_page(page);
243
244 reclaim_stat->recent_scanned[file]++;
245 if (rotated)
246 reclaim_stat->recent_rotated[file]++;
247
248 if (!memcg_reclaim_stat)
249 return;
250
251 memcg_reclaim_stat->recent_scanned[file]++;
252 if (rotated)
253 memcg_reclaim_stat->recent_rotated[file]++;
254}
255
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256/*
Linus Torvalds7a608572011-01-17 14:42:19 -0800257 * FIXME: speed this up?
Linus Torvalds1da177e2005-04-16 15:20:36 -0700258 */
Harvey Harrison920c7a52008-02-04 22:29:26 -0800259void activate_page(struct page *page)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700260{
261 struct zone *zone = page_zone(page);
262
263 spin_lock_irq(&zone->lru_lock);
Linus Torvalds7a608572011-01-17 14:42:19 -0800264 if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) {
265 int file = page_is_file_cache(page);
266 int lru = page_lru_base_type(page);
267 del_page_from_lru_list(zone, page, lru);
268
269 SetPageActive(page);
270 lru += LRU_ACTIVE;
271 add_page_to_lru_list(zone, page, lru);
272 __count_vm_event(PGACTIVATE);
273
274 update_page_reclaim_stat(zone, page, file, 1);
275 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700276 spin_unlock_irq(&zone->lru_lock);
277}
278
279/*
280 * Mark a page as having seen activity.
281 *
282 * inactive,unreferenced -> inactive,referenced
283 * inactive,referenced -> active,unreferenced
284 * active,unreferenced -> active,referenced
285 */
Harvey Harrison920c7a52008-02-04 22:29:26 -0800286void mark_page_accessed(struct page *page)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700287{
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700288 if (!PageActive(page) && !PageUnevictable(page) &&
289 PageReferenced(page) && PageLRU(page)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700290 activate_page(page);
291 ClearPageReferenced(page);
292 } else if (!PageReferenced(page)) {
293 SetPageReferenced(page);
294 }
295}
296
297EXPORT_SYMBOL(mark_page_accessed);
298
KOSAKI Motohirof04e9eb2008-10-18 20:26:19 -0700299void __lru_cache_add(struct page *page, enum lru_list lru)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700300{
KOSAKI Motohirof04e9eb2008-10-18 20:26:19 -0700301 struct pagevec *pvec = &get_cpu_var(lru_add_pvecs)[lru];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700302
303 page_cache_get(page);
304 if (!pagevec_add(pvec, page))
KOSAKI Motohirof04e9eb2008-10-18 20:26:19 -0700305 ____pagevec_lru_add(pvec, lru);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700306 put_cpu_var(lru_add_pvecs);
307}
Miklos Szeredi47846b02010-05-25 15:06:06 +0200308EXPORT_SYMBOL(__lru_cache_add);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700309
KOSAKI Motohirof04e9eb2008-10-18 20:26:19 -0700310/**
311 * lru_cache_add_lru - add a page to a page list
312 * @page: the page to be added to the LRU.
313 * @lru: the LRU list to which the page is added.
314 */
315void lru_cache_add_lru(struct page *page, enum lru_list lru)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700316{
KOSAKI Motohirof04e9eb2008-10-18 20:26:19 -0700317 if (PageActive(page)) {
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700318 VM_BUG_ON(PageUnevictable(page));
KOSAKI Motohirof04e9eb2008-10-18 20:26:19 -0700319 ClearPageActive(page);
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700320 } else if (PageUnevictable(page)) {
321 VM_BUG_ON(PageActive(page));
322 ClearPageUnevictable(page);
KOSAKI Motohirof04e9eb2008-10-18 20:26:19 -0700323 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700324
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700325 VM_BUG_ON(PageLRU(page) || PageActive(page) || PageUnevictable(page));
KOSAKI Motohirof04e9eb2008-10-18 20:26:19 -0700326 __lru_cache_add(page, lru);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700327}
328
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700329/**
330 * add_page_to_unevictable_list - add a page to the unevictable list
331 * @page: the page to be added to the unevictable list
332 *
333 * Add page directly to its zone's unevictable list. To avoid races with
334 * tasks that might be making the page evictable, through eg. munlock,
335 * munmap or exit, while it's not on the lru, we want to add the page
336 * while it's locked or otherwise "invisible" to other tasks. This is
337 * difficult to do when using the pagevec cache, so bypass that.
338 */
339void add_page_to_unevictable_list(struct page *page)
340{
341 struct zone *zone = page_zone(page);
342
343 spin_lock_irq(&zone->lru_lock);
344 SetPageUnevictable(page);
345 SetPageLRU(page);
346 add_page_to_lru_list(zone, page, LRU_UNEVICTABLE);
347 spin_unlock_irq(&zone->lru_lock);
348}
349
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700350/*
Minchan Kim31560182011-03-22 16:32:52 -0700351 * If the page can not be invalidated, it is moved to the
352 * inactive list to speed up its reclaim. It is moved to the
353 * head of the list, rather than the tail, to give the flusher
354 * threads some time to write it out, as this is much more
355 * effective than the single-page writeout from reclaim.
356 */
357static void lru_deactivate(struct page *page, struct zone *zone)
358{
359 int lru, file;
360
361 if (!PageLRU(page) || !PageActive(page))
362 return;
363
364 /* Some processes are using the page */
365 if (page_mapped(page))
366 return;
367
368 file = page_is_file_cache(page);
369 lru = page_lru_base_type(page);
370 del_page_from_lru_list(zone, page, lru + LRU_ACTIVE);
371 ClearPageActive(page);
372 ClearPageReferenced(page);
373 add_page_to_lru_list(zone, page, lru);
374 __count_vm_event(PGDEACTIVATE);
375
376 update_page_reclaim_stat(zone, page, file, 0);
377}
378
379static void ____pagevec_lru_deactivate(struct pagevec *pvec)
380{
381 int i;
382 struct zone *zone = NULL;
383
384 for (i = 0; i < pagevec_count(pvec); i++) {
385 struct page *page = pvec->pages[i];
386 struct zone *pagezone = page_zone(page);
387
388 if (pagezone != zone) {
389 if (zone)
390 spin_unlock_irq(&zone->lru_lock);
391 zone = pagezone;
392 spin_lock_irq(&zone->lru_lock);
393 }
394 lru_deactivate(page, zone);
395 }
396 if (zone)
397 spin_unlock_irq(&zone->lru_lock);
398
399 release_pages(pvec->pages, pvec->nr, pvec->cold);
400 pagevec_reinit(pvec);
401}
402
403
404/*
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700405 * Drain pages out of the cpu's pagevecs.
406 * Either "cpu" is the current CPU, and preemption has already been
407 * disabled; or "cpu" is being hot-unplugged, and is already dead.
408 */
409static void drain_cpu_pagevecs(int cpu)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700410{
KOSAKI Motohirof04e9eb2008-10-18 20:26:19 -0700411 struct pagevec *pvecs = per_cpu(lru_add_pvecs, cpu);
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700412 struct pagevec *pvec;
KOSAKI Motohirof04e9eb2008-10-18 20:26:19 -0700413 int lru;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700414
KOSAKI Motohirof04e9eb2008-10-18 20:26:19 -0700415 for_each_lru(lru) {
416 pvec = &pvecs[lru - LRU_BASE];
417 if (pagevec_count(pvec))
418 ____pagevec_lru_add(pvec, lru);
419 }
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700420
421 pvec = &per_cpu(lru_rotate_pvecs, cpu);
422 if (pagevec_count(pvec)) {
423 unsigned long flags;
424
425 /* No harm done if a racing interrupt already did this */
426 local_irq_save(flags);
427 pagevec_move_tail(pvec);
428 local_irq_restore(flags);
429 }
Minchan Kim31560182011-03-22 16:32:52 -0700430
431 pvec = &per_cpu(lru_deactivate_pvecs, cpu);
432 if (pagevec_count(pvec))
433 ____pagevec_lru_deactivate(pvec);
434}
435
436/**
437 * deactivate_page - forcefully deactivate a page
438 * @page: page to deactivate
439 *
440 * This function hints the VM that @page is a good reclaim candidate,
441 * for example if its invalidation fails due to the page being dirty
442 * or under writeback.
443 */
444void deactivate_page(struct page *page)
445{
446 if (likely(get_page_unless_zero(page))) {
447 struct pagevec *pvec = &get_cpu_var(lru_deactivate_pvecs);
448
449 if (!pagevec_add(pvec, page))
450 ____pagevec_lru_deactivate(pvec);
451 put_cpu_var(lru_deactivate_pvecs);
452 }
Andrew Morton80bfed92006-01-06 00:11:14 -0800453}
454
455void lru_add_drain(void)
456{
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700457 drain_cpu_pagevecs(get_cpu());
Andrew Morton80bfed92006-01-06 00:11:14 -0800458 put_cpu();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700459}
460
David Howellsc4028952006-11-22 14:57:56 +0000461static void lru_add_drain_per_cpu(struct work_struct *dummy)
Nick Piggin053837f2006-01-18 17:42:27 -0800462{
463 lru_add_drain();
464}
465
466/*
467 * Returns 0 for success
468 */
469int lru_add_drain_all(void)
470{
David Howellsc4028952006-11-22 14:57:56 +0000471 return schedule_on_each_cpu(lru_add_drain_per_cpu);
Nick Piggin053837f2006-01-18 17:42:27 -0800472}
473
Linus Torvalds1da177e2005-04-16 15:20:36 -0700474/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700475 * Batched page_cache_release(). Decrement the reference count on all the
476 * passed pages. If it fell to zero then remove the page from the LRU and
477 * free it.
478 *
479 * Avoid taking zone->lru_lock if possible, but if it is taken, retain it
480 * for the remainder of the operation.
481 *
Fernando Luis Vazquez Caoab33dc02008-07-29 22:33:40 -0700482 * The locking in this function is against shrink_inactive_list(): we recheck
483 * the page count inside the lock to see whether shrink_inactive_list()
484 * grabbed the page via the LRU. If it did, give up: shrink_inactive_list()
485 * will free it.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700486 */
487void release_pages(struct page **pages, int nr, int cold)
488{
489 int i;
490 struct pagevec pages_to_free;
491 struct zone *zone = NULL;
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700492 unsigned long uninitialized_var(flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700493
494 pagevec_init(&pages_to_free, cold);
495 for (i = 0; i < nr; i++) {
496 struct page *page = pages[i];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700497
Nick Piggin8519fb32006-02-07 12:58:52 -0800498 if (unlikely(PageCompound(page))) {
499 if (zone) {
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700500 spin_unlock_irqrestore(&zone->lru_lock, flags);
Nick Piggin8519fb32006-02-07 12:58:52 -0800501 zone = NULL;
502 }
503 put_compound_page(page);
504 continue;
505 }
506
Nick Pigginb5810032005-10-29 18:16:12 -0700507 if (!put_page_testzero(page))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700508 continue;
509
Nick Piggin46453a62006-03-22 00:07:58 -0800510 if (PageLRU(page)) {
511 struct zone *pagezone = page_zone(page);
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700512
Nick Piggin46453a62006-03-22 00:07:58 -0800513 if (pagezone != zone) {
514 if (zone)
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700515 spin_unlock_irqrestore(&zone->lru_lock,
516 flags);
Nick Piggin46453a62006-03-22 00:07:58 -0800517 zone = pagezone;
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700518 spin_lock_irqsave(&zone->lru_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700519 }
Nick Piggin725d7042006-09-25 23:30:55 -0700520 VM_BUG_ON(!PageLRU(page));
Nick Piggin67453912006-03-22 00:08:00 -0800521 __ClearPageLRU(page);
Nick Piggin46453a62006-03-22 00:07:58 -0800522 del_page_from_lru(zone, page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700523 }
Nick Piggin46453a62006-03-22 00:07:58 -0800524
525 if (!pagevec_add(&pages_to_free, page)) {
526 if (zone) {
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700527 spin_unlock_irqrestore(&zone->lru_lock, flags);
Nick Piggin46453a62006-03-22 00:07:58 -0800528 zone = NULL;
529 }
530 __pagevec_free(&pages_to_free);
531 pagevec_reinit(&pages_to_free);
532 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700533 }
534 if (zone)
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700535 spin_unlock_irqrestore(&zone->lru_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700536
537 pagevec_free(&pages_to_free);
538}
Miklos Szeredi0be85572010-10-27 15:34:46 -0700539EXPORT_SYMBOL(release_pages);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700540
541/*
542 * The pages which we're about to release may be in the deferred lru-addition
543 * queues. That would prevent them from really being freed right now. That's
544 * OK from a correctness point of view but is inefficient - those pages may be
545 * cache-warm and we want to give them back to the page allocator ASAP.
546 *
547 * So __pagevec_release() will drain those queues here. __pagevec_lru_add()
548 * and __pagevec_lru_add_active() call release_pages() directly to avoid
549 * mutual recursion.
550 */
551void __pagevec_release(struct pagevec *pvec)
552{
553 lru_add_drain();
554 release_pages(pvec->pages, pagevec_count(pvec), pvec->cold);
555 pagevec_reinit(pvec);
556}
557
Steve French7f285702005-11-01 10:22:55 -0800558EXPORT_SYMBOL(__pagevec_release);
559
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800560/* used by __split_huge_page_refcount() */
561void lru_add_page_tail(struct zone* zone,
562 struct page *page, struct page *page_tail)
563{
564 int active;
565 enum lru_list lru;
566 const int file = 0;
567 struct list_head *head;
568
569 VM_BUG_ON(!PageHead(page));
570 VM_BUG_ON(PageCompound(page_tail));
571 VM_BUG_ON(PageLRU(page_tail));
572 VM_BUG_ON(!spin_is_locked(&zone->lru_lock));
573
574 SetPageLRU(page_tail);
575
576 if (page_evictable(page_tail, NULL)) {
577 if (PageActive(page)) {
578 SetPageActive(page_tail);
579 active = 1;
580 lru = LRU_ACTIVE_ANON;
581 } else {
582 active = 0;
583 lru = LRU_INACTIVE_ANON;
584 }
585 update_page_reclaim_stat(zone, page_tail, file, active);
586 if (likely(PageLRU(page)))
587 head = page->lru.prev;
588 else
589 head = &zone->lru[lru].list;
590 __add_page_to_lru_list(zone, page_tail, lru, head);
591 } else {
592 SetPageUnevictable(page_tail);
593 add_page_to_lru_list(zone, page_tail, LRU_UNEVICTABLE);
594 }
595}
596
Linus Torvalds1da177e2005-04-16 15:20:36 -0700597/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700598 * Add the passed pages to the LRU, then drop the caller's refcount
599 * on them. Reinitialises the caller's pagevec.
600 */
KOSAKI Motohirof04e9eb2008-10-18 20:26:19 -0700601void ____pagevec_lru_add(struct pagevec *pvec, enum lru_list lru)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700602{
Linus Torvalds83896fb2011-01-17 14:42:34 -0800603 int i;
604 struct zone *zone = NULL;
605
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700606 VM_BUG_ON(is_unevictable_lru(lru));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700607
Linus Torvalds83896fb2011-01-17 14:42:34 -0800608 for (i = 0; i < pagevec_count(pvec); i++) {
609 struct page *page = pvec->pages[i];
610 struct zone *pagezone = page_zone(page);
611 int file;
612 int active;
613
614 if (pagezone != zone) {
615 if (zone)
616 spin_unlock_irq(&zone->lru_lock);
617 zone = pagezone;
618 spin_lock_irq(&zone->lru_lock);
619 }
620 VM_BUG_ON(PageActive(page));
621 VM_BUG_ON(PageUnevictable(page));
622 VM_BUG_ON(PageLRU(page));
623 SetPageLRU(page);
624 active = is_active_lru(lru);
625 file = is_file_lru(lru);
626 if (active)
627 SetPageActive(page);
628 update_page_reclaim_stat(zone, page, file, active);
629 add_page_to_lru_list(zone, page, lru);
630 }
631 if (zone)
632 spin_unlock_irq(&zone->lru_lock);
633 release_pages(pvec->pages, pvec->nr, pvec->cold);
634 pagevec_reinit(pvec);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700635}
636
KOSAKI Motohirof04e9eb2008-10-18 20:26:19 -0700637EXPORT_SYMBOL(____pagevec_lru_add);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700638
639/*
640 * Try to drop buffers from the pages in a pagevec
641 */
642void pagevec_strip(struct pagevec *pvec)
643{
644 int i;
645
646 for (i = 0; i < pagevec_count(pvec); i++) {
647 struct page *page = pvec->pages[i];
648
David Howells266cf652009-04-03 16:42:36 +0100649 if (page_has_private(page) && trylock_page(page)) {
650 if (page_has_private(page))
Christoph Lameter5b40dc72006-03-16 23:04:07 -0800651 try_to_release_page(page, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700652 unlock_page(page);
653 }
654 }
655}
656
657/**
658 * pagevec_lookup - gang pagecache lookup
659 * @pvec: Where the resulting pages are placed
660 * @mapping: The address_space to search
661 * @start: The starting page index
662 * @nr_pages: The maximum number of pages
663 *
664 * pagevec_lookup() will search for and return a group of up to @nr_pages pages
665 * in the mapping. The pages are placed in @pvec. pagevec_lookup() takes a
666 * reference against the pages in @pvec.
667 *
668 * The search returns a group of mapping-contiguous pages with ascending
669 * indexes. There may be holes in the indices due to not-present pages.
670 *
671 * pagevec_lookup() returns the number of pages which were found.
672 */
673unsigned pagevec_lookup(struct pagevec *pvec, struct address_space *mapping,
674 pgoff_t start, unsigned nr_pages)
675{
676 pvec->nr = find_get_pages(mapping, start, nr_pages, pvec->pages);
677 return pagevec_count(pvec);
678}
679
Christoph Hellwig78539fd2006-01-11 20:47:41 +1100680EXPORT_SYMBOL(pagevec_lookup);
681
Linus Torvalds1da177e2005-04-16 15:20:36 -0700682unsigned pagevec_lookup_tag(struct pagevec *pvec, struct address_space *mapping,
683 pgoff_t *index, int tag, unsigned nr_pages)
684{
685 pvec->nr = find_get_pages_tag(mapping, index, tag,
686 nr_pages, pvec->pages);
687 return pagevec_count(pvec);
688}
689
Steve French7f285702005-11-01 10:22:55 -0800690EXPORT_SYMBOL(pagevec_lookup_tag);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700691
Linus Torvalds1da177e2005-04-16 15:20:36 -0700692/*
693 * Perform any setup for the swap system
694 */
695void __init swap_setup(void)
696{
Jan Beulich44813742009-09-21 17:03:05 -0700697 unsigned long megs = totalram_pages >> (20 - PAGE_SHIFT);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700698
Peter Zijlstrae0bf68d2007-10-16 23:25:46 -0700699#ifdef CONFIG_SWAP
700 bdi_init(swapper_space.backing_dev_info);
701#endif
702
Linus Torvalds1da177e2005-04-16 15:20:36 -0700703 /* Use a smaller cluster for small-memory machines */
704 if (megs < 16)
705 page_cluster = 2;
706 else
707 page_cluster = 3;
708 /*
709 * Right now other parts of the system means that we
710 * _really_ don't want to cluster much more
711 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700712}