blob: 7d7f80c8044aa80f3bd3f5dc3b6ed9e4401b6c8b [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>
Paul Gortmakerb95f1b312011-10-16 02:01:52 -040024#include <linux/export.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070025#include <linux/mm_inline.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070026#include <linux/percpu_counter.h>
27#include <linux/percpu.h>
28#include <linux/cpu.h>
29#include <linux/notifier.h>
Peter Zijlstrae0bf68d2007-10-16 23:25:46 -070030#include <linux/backing-dev.h>
Balbir Singh66e17072008-02-07 00:13:56 -080031#include <linux/memcontrol.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090032#include <linux/gfp.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070033
Lee Schermerhorn64d65192008-10-18 20:26:52 -070034#include "internal.h"
35
Linus Torvalds1da177e2005-04-16 15:20:36 -070036/* How many pages do we try to swap or page in/out together? */
37int page_cluster;
38
KOSAKI Motohirof04e9eb2008-10-18 20:26:19 -070039static DEFINE_PER_CPU(struct pagevec[NR_LRU_LISTS], lru_add_pvecs);
Vegard Nossumf84f95042008-07-23 21:28:14 -070040static DEFINE_PER_CPU(struct pagevec, lru_rotate_pvecs);
Minchan Kim31560182011-03-22 16:32:52 -070041static DEFINE_PER_CPU(struct pagevec, lru_deactivate_pvecs);
Hisashi Hifumi902aaed2007-10-16 01:24:52 -070042
Adrian Bunkb2213852006-09-25 23:31:02 -070043/*
44 * This path almost never happens for VM activity - pages are normally
45 * freed via pagevecs. But it gets used by networking.
46 */
Harvey Harrison920c7a52008-02-04 22:29:26 -080047static void __page_cache_release(struct page *page)
Adrian Bunkb2213852006-09-25 23:31:02 -070048{
49 if (PageLRU(page)) {
Adrian Bunkb2213852006-09-25 23:31:02 -070050 struct zone *zone = page_zone(page);
Hugh Dickinsfa9add62012-05-29 15:07:09 -070051 struct lruvec *lruvec;
52 unsigned long flags;
Adrian Bunkb2213852006-09-25 23:31:02 -070053
54 spin_lock_irqsave(&zone->lru_lock, flags);
Hugh Dickinsfa9add62012-05-29 15:07:09 -070055 lruvec = mem_cgroup_page_lruvec(page, zone);
Adrian Bunkb2213852006-09-25 23:31:02 -070056 VM_BUG_ON(!PageLRU(page));
57 __ClearPageLRU(page);
Hugh Dickinsfa9add62012-05-29 15:07:09 -070058 del_page_from_lru_list(page, lruvec, page_off_lru(page));
Adrian Bunkb2213852006-09-25 23:31:02 -070059 spin_unlock_irqrestore(&zone->lru_lock, flags);
60 }
Andrea Arcangeli91807062011-01-13 15:46:32 -080061}
62
63static void __put_single_page(struct page *page)
64{
65 __page_cache_release(page);
Li Hongfc916682010-03-05 13:41:54 -080066 free_hot_cold_page(page, 0);
Adrian Bunkb2213852006-09-25 23:31:02 -070067}
68
Andrea Arcangeli91807062011-01-13 15:46:32 -080069static void __put_compound_page(struct page *page)
70{
71 compound_page_dtor *dtor;
72
73 __page_cache_release(page);
74 dtor = get_compound_page_dtor(page);
75 (*dtor)(page);
76}
77
Nick Piggin8519fb32006-02-07 12:58:52 -080078static void put_compound_page(struct page *page)
79{
Andrea Arcangeli91807062011-01-13 15:46:32 -080080 if (unlikely(PageTail(page))) {
81 /* __split_huge_page_refcount can run under us */
Andrea Arcangeli70b50f92011-11-02 13:36:59 -070082 struct page *page_head = compound_trans_head(page);
83
84 if (likely(page != page_head &&
85 get_page_unless_zero(page_head))) {
Andrea Arcangeli91807062011-01-13 15:46:32 -080086 unsigned long flags;
Pravin B Shelar5bf5f032012-05-29 15:06:49 -070087
88 /*
89 * THP can not break up slab pages so avoid taking
90 * compound_lock(). Slab performs non-atomic bit ops
91 * on page->flags for better performance. In particular
92 * slab_unlock() in slub used to be a hot path. It is
93 * still hot on arches that do not support
94 * this_cpu_cmpxchg_double().
95 */
96 if (PageSlab(page_head)) {
97 if (PageTail(page)) {
98 if (put_page_testzero(page_head))
99 VM_BUG_ON(1);
100
101 atomic_dec(&page->_mapcount);
102 goto skip_lock_tail;
103 } else
104 goto skip_lock;
105 }
Andrea Arcangeli91807062011-01-13 15:46:32 -0800106 /*
Andrea Arcangeli70b50f92011-11-02 13:36:59 -0700107 * page_head wasn't a dangling pointer but it
108 * may not be a head page anymore by the time
109 * we obtain the lock. That is ok as long as it
110 * can't be freed from under us.
Andrea Arcangeli91807062011-01-13 15:46:32 -0800111 */
Andrea Arcangeli91807062011-01-13 15:46:32 -0800112 flags = compound_lock_irqsave(page_head);
113 if (unlikely(!PageTail(page))) {
114 /* __split_huge_page_refcount run before us */
115 compound_unlock_irqrestore(page_head, flags);
Pravin B Shelar5bf5f032012-05-29 15:06:49 -0700116skip_lock:
Andrea Arcangeli91807062011-01-13 15:46:32 -0800117 if (put_page_testzero(page_head))
118 __put_single_page(page_head);
Pravin B Shelar5bf5f032012-05-29 15:06:49 -0700119out_put_single:
Andrea Arcangeli91807062011-01-13 15:46:32 -0800120 if (put_page_testzero(page))
121 __put_single_page(page);
122 return;
123 }
124 VM_BUG_ON(page_head != page->first_page);
125 /*
126 * We can release the refcount taken by
Andrea Arcangeli70b50f92011-11-02 13:36:59 -0700127 * get_page_unless_zero() now that
128 * __split_huge_page_refcount() is blocked on
129 * the compound_lock.
Andrea Arcangeli91807062011-01-13 15:46:32 -0800130 */
131 if (put_page_testzero(page_head))
132 VM_BUG_ON(1);
133 /* __split_huge_page_refcount will wait now */
Andrea Arcangeli70b50f92011-11-02 13:36:59 -0700134 VM_BUG_ON(page_mapcount(page) <= 0);
135 atomic_dec(&page->_mapcount);
Andrea Arcangeli91807062011-01-13 15:46:32 -0800136 VM_BUG_ON(atomic_read(&page_head->_count) <= 0);
Andrea Arcangeli70b50f92011-11-02 13:36:59 -0700137 VM_BUG_ON(atomic_read(&page->_count) != 0);
Andrea Arcangeli91807062011-01-13 15:46:32 -0800138 compound_unlock_irqrestore(page_head, flags);
Pravin B Shelar5bf5f032012-05-29 15:06:49 -0700139
140skip_lock_tail:
Andrea Arcangelia95a82e2011-01-13 15:46:33 -0800141 if (put_page_testzero(page_head)) {
142 if (PageHead(page_head))
143 __put_compound_page(page_head);
144 else
145 __put_single_page(page_head);
146 }
Andrea Arcangeli91807062011-01-13 15:46:32 -0800147 } else {
148 /* page_head is a dangling pointer */
149 VM_BUG_ON(PageTail(page));
150 goto out_put_single;
151 }
152 } else if (put_page_testzero(page)) {
153 if (PageHead(page))
154 __put_compound_page(page);
155 else
156 __put_single_page(page);
Nick Piggin8519fb32006-02-07 12:58:52 -0800157 }
158}
159
Linus Torvalds1da177e2005-04-16 15:20:36 -0700160void put_page(struct page *page)
161{
Nick Piggin8519fb32006-02-07 12:58:52 -0800162 if (unlikely(PageCompound(page)))
163 put_compound_page(page);
164 else if (put_page_testzero(page))
Andrea Arcangeli91807062011-01-13 15:46:32 -0800165 __put_single_page(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700166}
167EXPORT_SYMBOL(put_page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700168
Andrea Arcangeli70b50f92011-11-02 13:36:59 -0700169/*
170 * This function is exported but must not be called by anything other
171 * than get_page(). It implements the slow path of get_page().
172 */
173bool __get_page_tail(struct page *page)
174{
175 /*
176 * This takes care of get_page() if run on a tail page
177 * returned by one of the get_user_pages/follow_page variants.
178 * get_user_pages/follow_page itself doesn't need the compound
179 * lock because it runs __get_page_tail_foll() under the
180 * proper PT lock that already serializes against
181 * split_huge_page().
182 */
183 unsigned long flags;
184 bool got = false;
185 struct page *page_head = compound_trans_head(page);
186
187 if (likely(page != page_head && get_page_unless_zero(page_head))) {
Pravin B Shelar5bf5f032012-05-29 15:06:49 -0700188
189 /* Ref to put_compound_page() comment. */
190 if (PageSlab(page_head)) {
191 if (likely(PageTail(page))) {
192 __get_page_tail_foll(page, false);
193 return true;
194 } else {
195 put_page(page_head);
196 return false;
197 }
198 }
199
Andrea Arcangeli70b50f92011-11-02 13:36:59 -0700200 /*
201 * page_head wasn't a dangling pointer but it
202 * may not be a head page anymore by the time
203 * we obtain the lock. That is ok as long as it
204 * can't be freed from under us.
205 */
206 flags = compound_lock_irqsave(page_head);
207 /* here __split_huge_page_refcount won't run anymore */
208 if (likely(PageTail(page))) {
209 __get_page_tail_foll(page, false);
210 got = true;
211 }
212 compound_unlock_irqrestore(page_head, flags);
213 if (unlikely(!got))
214 put_page(page_head);
215 }
216 return got;
217}
218EXPORT_SYMBOL(__get_page_tail);
219
Alexander Zarochentsev1d7ea732006-08-13 23:24:27 -0700220/**
Randy Dunlap76824862008-03-19 17:00:40 -0700221 * put_pages_list() - release a list of pages
222 * @pages: list of pages threaded on page->lru
Alexander Zarochentsev1d7ea732006-08-13 23:24:27 -0700223 *
224 * Release a list of pages which are strung together on page.lru. Currently
225 * used by read_cache_pages() and related error recovery code.
Alexander Zarochentsev1d7ea732006-08-13 23:24:27 -0700226 */
227void put_pages_list(struct list_head *pages)
228{
229 while (!list_empty(pages)) {
230 struct page *victim;
231
232 victim = list_entry(pages->prev, struct page, lru);
233 list_del(&victim->lru);
234 page_cache_release(victim);
235 }
236}
237EXPORT_SYMBOL(put_pages_list);
238
Mel Gorman18022c52012-07-31 16:44:51 -0700239/*
240 * get_kernel_pages() - pin kernel pages in memory
241 * @kiov: An array of struct kvec structures
242 * @nr_segs: number of segments to pin
243 * @write: pinning for read/write, currently ignored
244 * @pages: array that receives pointers to the pages pinned.
245 * Should be at least nr_segs long.
246 *
247 * Returns number of pages pinned. This may be fewer than the number
248 * requested. If nr_pages is 0 or negative, returns 0. If no pages
249 * were pinned, returns -errno. Each page returned must be released
250 * with a put_page() call when it is finished with.
251 */
252int get_kernel_pages(const struct kvec *kiov, int nr_segs, int write,
253 struct page **pages)
254{
255 int seg;
256
257 for (seg = 0; seg < nr_segs; seg++) {
258 if (WARN_ON(kiov[seg].iov_len != PAGE_SIZE))
259 return seg;
260
261 /* virt_to_page sanity checks the PFN */
262 pages[seg] = virt_to_page(kiov[seg].iov_base);
263 page_cache_get(pages[seg]);
264 }
265
266 return seg;
267}
268EXPORT_SYMBOL_GPL(get_kernel_pages);
269
270/*
271 * get_kernel_page() - pin a kernel page in memory
272 * @start: starting kernel address
273 * @write: pinning for read/write, currently ignored
274 * @pages: array that receives pointer to the page pinned.
275 * Must be at least nr_segs long.
276 *
277 * Returns 1 if page is pinned. If the page was not pinned, returns
278 * -errno. The page returned must be released with a put_page() call
279 * when it is finished with.
280 */
281int get_kernel_page(unsigned long start, int write, struct page **pages)
282{
283 const struct kvec kiov = {
284 .iov_base = (void *)start,
285 .iov_len = PAGE_SIZE
286 };
287
288 return get_kernel_pages(&kiov, 1, write, pages);
289}
290EXPORT_SYMBOL_GPL(get_kernel_page);
291
Shaohua Li3dd7ae82011-03-22 16:33:45 -0700292static void pagevec_lru_move_fn(struct pagevec *pvec,
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700293 void (*move_fn)(struct page *page, struct lruvec *lruvec, void *arg),
294 void *arg)
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700295{
296 int i;
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700297 struct zone *zone = NULL;
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700298 struct lruvec *lruvec;
Shaohua Li3dd7ae82011-03-22 16:33:45 -0700299 unsigned long flags = 0;
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700300
301 for (i = 0; i < pagevec_count(pvec); i++) {
302 struct page *page = pvec->pages[i];
303 struct zone *pagezone = page_zone(page);
304
305 if (pagezone != zone) {
306 if (zone)
Shaohua Li3dd7ae82011-03-22 16:33:45 -0700307 spin_unlock_irqrestore(&zone->lru_lock, flags);
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700308 zone = pagezone;
Shaohua Li3dd7ae82011-03-22 16:33:45 -0700309 spin_lock_irqsave(&zone->lru_lock, flags);
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700310 }
Shaohua Li3dd7ae82011-03-22 16:33:45 -0700311
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700312 lruvec = mem_cgroup_page_lruvec(page, zone);
313 (*move_fn)(page, lruvec, arg);
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700314 }
315 if (zone)
Shaohua Li3dd7ae82011-03-22 16:33:45 -0700316 spin_unlock_irqrestore(&zone->lru_lock, flags);
Linus Torvalds83896fb2011-01-17 14:42:34 -0800317 release_pages(pvec->pages, pvec->nr, pvec->cold);
318 pagevec_reinit(pvec);
Shaohua Lid8505de2011-01-13 15:47:33 -0800319}
320
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700321static void pagevec_move_tail_fn(struct page *page, struct lruvec *lruvec,
322 void *arg)
Shaohua Li3dd7ae82011-03-22 16:33:45 -0700323{
324 int *pgmoved = arg;
Shaohua Li3dd7ae82011-03-22 16:33:45 -0700325
326 if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) {
327 enum lru_list lru = page_lru_base_type(page);
Johannes Weiner925b7672012-01-12 17:18:15 -0800328 list_move_tail(&page->lru, &lruvec->lists[lru]);
Shaohua Li3dd7ae82011-03-22 16:33:45 -0700329 (*pgmoved)++;
330 }
331}
332
333/*
334 * pagevec_move_tail() must be called with IRQ disabled.
335 * Otherwise this may cause nasty races.
336 */
337static void pagevec_move_tail(struct pagevec *pvec)
338{
339 int pgmoved = 0;
340
341 pagevec_lru_move_fn(pvec, pagevec_move_tail_fn, &pgmoved);
342 __count_vm_events(PGROTATED, pgmoved);
343}
344
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700345/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700346 * Writeback is about to end against a page which has been marked for immediate
347 * reclaim. If it still appears to be reclaimable, move it to the tail of the
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700348 * inactive list.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700349 */
Shaohua Li3dd7ae82011-03-22 16:33:45 -0700350void rotate_reclaimable_page(struct page *page)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700351{
Miklos Szerediac6aadb2008-04-28 02:12:38 -0700352 if (!PageLocked(page) && !PageDirty(page) && !PageActive(page) &&
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700353 !PageUnevictable(page) && PageLRU(page)) {
Miklos Szerediac6aadb2008-04-28 02:12:38 -0700354 struct pagevec *pvec;
355 unsigned long flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700356
Miklos Szerediac6aadb2008-04-28 02:12:38 -0700357 page_cache_get(page);
358 local_irq_save(flags);
359 pvec = &__get_cpu_var(lru_rotate_pvecs);
360 if (!pagevec_add(pvec, page))
361 pagevec_move_tail(pvec);
362 local_irq_restore(flags);
363 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700364}
365
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700366static void update_page_reclaim_stat(struct lruvec *lruvec,
KOSAKI Motohiro3e2f41f2009-01-07 18:08:20 -0800367 int file, int rotated)
368{
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700369 struct zone_reclaim_stat *reclaim_stat = &lruvec->reclaim_stat;
KOSAKI Motohiro3e2f41f2009-01-07 18:08:20 -0800370
371 reclaim_stat->recent_scanned[file]++;
372 if (rotated)
373 reclaim_stat->recent_rotated[file]++;
KOSAKI Motohiro3e2f41f2009-01-07 18:08:20 -0800374}
375
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700376static void __activate_page(struct page *page, struct lruvec *lruvec,
377 void *arg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700378{
Linus Torvalds7a608572011-01-17 14:42:19 -0800379 if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) {
380 int file = page_is_file_cache(page);
381 int lru = page_lru_base_type(page);
Linus Torvalds7a608572011-01-17 14:42:19 -0800382
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700383 del_page_from_lru_list(page, lruvec, lru);
Linus Torvalds7a608572011-01-17 14:42:19 -0800384 SetPageActive(page);
385 lru += LRU_ACTIVE;
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700386 add_page_to_lru_list(page, lruvec, lru);
Linus Torvalds7a608572011-01-17 14:42:19 -0800387
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700388 __count_vm_event(PGACTIVATE);
389 update_page_reclaim_stat(lruvec, file, 1);
Linus Torvalds7a608572011-01-17 14:42:19 -0800390 }
Shaohua Lieb709b02011-05-24 17:12:55 -0700391}
392
393#ifdef CONFIG_SMP
394static DEFINE_PER_CPU(struct pagevec, activate_page_pvecs);
395
396static void activate_page_drain(int cpu)
397{
398 struct pagevec *pvec = &per_cpu(activate_page_pvecs, cpu);
399
400 if (pagevec_count(pvec))
401 pagevec_lru_move_fn(pvec, __activate_page, NULL);
402}
403
404void activate_page(struct page *page)
405{
406 if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) {
407 struct pagevec *pvec = &get_cpu_var(activate_page_pvecs);
408
409 page_cache_get(page);
410 if (!pagevec_add(pvec, page))
411 pagevec_lru_move_fn(pvec, __activate_page, NULL);
412 put_cpu_var(activate_page_pvecs);
413 }
414}
415
416#else
417static inline void activate_page_drain(int cpu)
418{
419}
420
421void activate_page(struct page *page)
422{
423 struct zone *zone = page_zone(page);
424
425 spin_lock_irq(&zone->lru_lock);
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700426 __activate_page(page, mem_cgroup_page_lruvec(page, zone), NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700427 spin_unlock_irq(&zone->lru_lock);
428}
Shaohua Lieb709b02011-05-24 17:12:55 -0700429#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700430
431/*
432 * Mark a page as having seen activity.
433 *
434 * inactive,unreferenced -> inactive,referenced
435 * inactive,referenced -> active,unreferenced
436 * active,unreferenced -> active,referenced
437 */
Harvey Harrison920c7a52008-02-04 22:29:26 -0800438void mark_page_accessed(struct page *page)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700439{
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700440 if (!PageActive(page) && !PageUnevictable(page) &&
441 PageReferenced(page) && PageLRU(page)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700442 activate_page(page);
443 ClearPageReferenced(page);
444 } else if (!PageReferenced(page)) {
445 SetPageReferenced(page);
446 }
447}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700448EXPORT_SYMBOL(mark_page_accessed);
449
KOSAKI Motohirof04e9eb2008-10-18 20:26:19 -0700450void __lru_cache_add(struct page *page, enum lru_list lru)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700451{
KOSAKI Motohirof04e9eb2008-10-18 20:26:19 -0700452 struct pagevec *pvec = &get_cpu_var(lru_add_pvecs)[lru];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700453
454 page_cache_get(page);
455 if (!pagevec_add(pvec, page))
Hugh Dickins5095ae832012-01-12 17:19:58 -0800456 __pagevec_lru_add(pvec, lru);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700457 put_cpu_var(lru_add_pvecs);
458}
Miklos Szeredi47846b02010-05-25 15:06:06 +0200459EXPORT_SYMBOL(__lru_cache_add);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700460
KOSAKI Motohirof04e9eb2008-10-18 20:26:19 -0700461/**
462 * lru_cache_add_lru - add a page to a page list
463 * @page: the page to be added to the LRU.
464 * @lru: the LRU list to which the page is added.
465 */
466void lru_cache_add_lru(struct page *page, enum lru_list lru)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700467{
KOSAKI Motohirof04e9eb2008-10-18 20:26:19 -0700468 if (PageActive(page)) {
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700469 VM_BUG_ON(PageUnevictable(page));
KOSAKI Motohirof04e9eb2008-10-18 20:26:19 -0700470 ClearPageActive(page);
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700471 } else if (PageUnevictable(page)) {
472 VM_BUG_ON(PageActive(page));
473 ClearPageUnevictable(page);
KOSAKI Motohirof04e9eb2008-10-18 20:26:19 -0700474 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700475
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700476 VM_BUG_ON(PageLRU(page) || PageActive(page) || PageUnevictable(page));
KOSAKI Motohirof04e9eb2008-10-18 20:26:19 -0700477 __lru_cache_add(page, lru);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700478}
479
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700480/**
481 * add_page_to_unevictable_list - add a page to the unevictable list
482 * @page: the page to be added to the unevictable list
483 *
484 * Add page directly to its zone's unevictable list. To avoid races with
485 * tasks that might be making the page evictable, through eg. munlock,
486 * munmap or exit, while it's not on the lru, we want to add the page
487 * while it's locked or otherwise "invisible" to other tasks. This is
488 * difficult to do when using the pagevec cache, so bypass that.
489 */
490void add_page_to_unevictable_list(struct page *page)
491{
492 struct zone *zone = page_zone(page);
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700493 struct lruvec *lruvec;
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700494
495 spin_lock_irq(&zone->lru_lock);
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700496 lruvec = mem_cgroup_page_lruvec(page, zone);
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700497 SetPageUnevictable(page);
498 SetPageLRU(page);
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700499 add_page_to_lru_list(page, lruvec, LRU_UNEVICTABLE);
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700500 spin_unlock_irq(&zone->lru_lock);
501}
502
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700503/*
Minchan Kim31560182011-03-22 16:32:52 -0700504 * If the page can not be invalidated, it is moved to the
505 * inactive list to speed up its reclaim. It is moved to the
506 * head of the list, rather than the tail, to give the flusher
507 * threads some time to write it out, as this is much more
508 * effective than the single-page writeout from reclaim.
Minchan Kim278df9f2011-03-22 16:32:54 -0700509 *
510 * If the page isn't page_mapped and dirty/writeback, the page
511 * could reclaim asap using PG_reclaim.
512 *
513 * 1. active, mapped page -> none
514 * 2. active, dirty/writeback page -> inactive, head, PG_reclaim
515 * 3. inactive, mapped page -> none
516 * 4. inactive, dirty/writeback page -> inactive, head, PG_reclaim
517 * 5. inactive, clean -> inactive, tail
518 * 6. Others -> none
519 *
520 * In 4, why it moves inactive's head, the VM expects the page would
521 * be write it out by flusher threads as this is much more effective
522 * than the single-page writeout from reclaim.
Minchan Kim31560182011-03-22 16:32:52 -0700523 */
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700524static void lru_deactivate_fn(struct page *page, struct lruvec *lruvec,
525 void *arg)
Minchan Kim31560182011-03-22 16:32:52 -0700526{
527 int lru, file;
Minchan Kim278df9f2011-03-22 16:32:54 -0700528 bool active;
Minchan Kim31560182011-03-22 16:32:52 -0700529
Minchan Kim278df9f2011-03-22 16:32:54 -0700530 if (!PageLRU(page))
Minchan Kim31560182011-03-22 16:32:52 -0700531 return;
532
Minchan Kimbad49d92011-05-11 15:13:30 -0700533 if (PageUnevictable(page))
534 return;
535
Minchan Kim31560182011-03-22 16:32:52 -0700536 /* Some processes are using the page */
537 if (page_mapped(page))
538 return;
539
Minchan Kim278df9f2011-03-22 16:32:54 -0700540 active = PageActive(page);
Minchan Kim31560182011-03-22 16:32:52 -0700541 file = page_is_file_cache(page);
542 lru = page_lru_base_type(page);
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700543
544 del_page_from_lru_list(page, lruvec, lru + active);
Minchan Kim31560182011-03-22 16:32:52 -0700545 ClearPageActive(page);
546 ClearPageReferenced(page);
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700547 add_page_to_lru_list(page, lruvec, lru);
Minchan Kim31560182011-03-22 16:32:52 -0700548
Minchan Kim278df9f2011-03-22 16:32:54 -0700549 if (PageWriteback(page) || PageDirty(page)) {
550 /*
551 * PG_reclaim could be raced with end_page_writeback
552 * It can make readahead confusing. But race window
553 * is _really_ small and it's non-critical problem.
554 */
555 SetPageReclaim(page);
556 } else {
557 /*
558 * The page's writeback ends up during pagevec
559 * We moves tha page into tail of inactive.
560 */
Johannes Weiner925b7672012-01-12 17:18:15 -0800561 list_move_tail(&page->lru, &lruvec->lists[lru]);
Minchan Kim278df9f2011-03-22 16:32:54 -0700562 __count_vm_event(PGROTATED);
563 }
564
565 if (active)
566 __count_vm_event(PGDEACTIVATE);
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700567 update_page_reclaim_stat(lruvec, file, 0);
Minchan Kim31560182011-03-22 16:32:52 -0700568}
569
Minchan Kim31560182011-03-22 16:32:52 -0700570/*
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700571 * Drain pages out of the cpu's pagevecs.
572 * Either "cpu" is the current CPU, and preemption has already been
573 * disabled; or "cpu" is being hot-unplugged, and is already dead.
574 */
Konstantin Khlebnikovf0cb3c72012-03-21 16:34:06 -0700575void lru_add_drain_cpu(int cpu)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700576{
KOSAKI Motohirof04e9eb2008-10-18 20:26:19 -0700577 struct pagevec *pvecs = per_cpu(lru_add_pvecs, cpu);
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700578 struct pagevec *pvec;
KOSAKI Motohirof04e9eb2008-10-18 20:26:19 -0700579 int lru;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700580
KOSAKI Motohirof04e9eb2008-10-18 20:26:19 -0700581 for_each_lru(lru) {
582 pvec = &pvecs[lru - LRU_BASE];
583 if (pagevec_count(pvec))
Hugh Dickins5095ae832012-01-12 17:19:58 -0800584 __pagevec_lru_add(pvec, lru);
KOSAKI Motohirof04e9eb2008-10-18 20:26:19 -0700585 }
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700586
587 pvec = &per_cpu(lru_rotate_pvecs, cpu);
588 if (pagevec_count(pvec)) {
589 unsigned long flags;
590
591 /* No harm done if a racing interrupt already did this */
592 local_irq_save(flags);
593 pagevec_move_tail(pvec);
594 local_irq_restore(flags);
595 }
Minchan Kim31560182011-03-22 16:32:52 -0700596
597 pvec = &per_cpu(lru_deactivate_pvecs, cpu);
598 if (pagevec_count(pvec))
Shaohua Li3dd7ae82011-03-22 16:33:45 -0700599 pagevec_lru_move_fn(pvec, lru_deactivate_fn, NULL);
Shaohua Lieb709b02011-05-24 17:12:55 -0700600
601 activate_page_drain(cpu);
Minchan Kim31560182011-03-22 16:32:52 -0700602}
603
604/**
605 * deactivate_page - forcefully deactivate a page
606 * @page: page to deactivate
607 *
608 * This function hints the VM that @page is a good reclaim candidate,
609 * for example if its invalidation fails due to the page being dirty
610 * or under writeback.
611 */
612void deactivate_page(struct page *page)
613{
Minchan Kim821ed6b2011-05-24 17:12:31 -0700614 /*
615 * In a workload with many unevictable page such as mprotect, unevictable
616 * page deactivation for accelerating reclaim is pointless.
617 */
618 if (PageUnevictable(page))
619 return;
620
Minchan Kim31560182011-03-22 16:32:52 -0700621 if (likely(get_page_unless_zero(page))) {
622 struct pagevec *pvec = &get_cpu_var(lru_deactivate_pvecs);
623
624 if (!pagevec_add(pvec, page))
Shaohua Li3dd7ae82011-03-22 16:33:45 -0700625 pagevec_lru_move_fn(pvec, lru_deactivate_fn, NULL);
Minchan Kim31560182011-03-22 16:32:52 -0700626 put_cpu_var(lru_deactivate_pvecs);
627 }
Andrew Morton80bfed92006-01-06 00:11:14 -0800628}
629
630void lru_add_drain(void)
631{
Konstantin Khlebnikovf0cb3c72012-03-21 16:34:06 -0700632 lru_add_drain_cpu(get_cpu());
Andrew Morton80bfed92006-01-06 00:11:14 -0800633 put_cpu();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700634}
635
David Howellsc4028952006-11-22 14:57:56 +0000636static void lru_add_drain_per_cpu(struct work_struct *dummy)
Nick Piggin053837f2006-01-18 17:42:27 -0800637{
638 lru_add_drain();
639}
640
641/*
642 * Returns 0 for success
643 */
644int lru_add_drain_all(void)
645{
David Howellsc4028952006-11-22 14:57:56 +0000646 return schedule_on_each_cpu(lru_add_drain_per_cpu);
Nick Piggin053837f2006-01-18 17:42:27 -0800647}
648
Linus Torvalds1da177e2005-04-16 15:20:36 -0700649/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700650 * Batched page_cache_release(). Decrement the reference count on all the
651 * passed pages. If it fell to zero then remove the page from the LRU and
652 * free it.
653 *
654 * Avoid taking zone->lru_lock if possible, but if it is taken, retain it
655 * for the remainder of the operation.
656 *
Fernando Luis Vazquez Caoab33dc02008-07-29 22:33:40 -0700657 * The locking in this function is against shrink_inactive_list(): we recheck
658 * the page count inside the lock to see whether shrink_inactive_list()
659 * grabbed the page via the LRU. If it did, give up: shrink_inactive_list()
660 * will free it.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700661 */
662void release_pages(struct page **pages, int nr, int cold)
663{
664 int i;
Konstantin Khlebnikovcc598502012-01-10 15:07:04 -0800665 LIST_HEAD(pages_to_free);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700666 struct zone *zone = NULL;
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700667 struct lruvec *lruvec;
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700668 unsigned long uninitialized_var(flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700669
Linus Torvalds1da177e2005-04-16 15:20:36 -0700670 for (i = 0; i < nr; i++) {
671 struct page *page = pages[i];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700672
Nick Piggin8519fb32006-02-07 12:58:52 -0800673 if (unlikely(PageCompound(page))) {
674 if (zone) {
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700675 spin_unlock_irqrestore(&zone->lru_lock, flags);
Nick Piggin8519fb32006-02-07 12:58:52 -0800676 zone = NULL;
677 }
678 put_compound_page(page);
679 continue;
680 }
681
Nick Pigginb5810032005-10-29 18:16:12 -0700682 if (!put_page_testzero(page))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700683 continue;
684
Nick Piggin46453a62006-03-22 00:07:58 -0800685 if (PageLRU(page)) {
686 struct zone *pagezone = page_zone(page);
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700687
Nick Piggin46453a62006-03-22 00:07:58 -0800688 if (pagezone != zone) {
689 if (zone)
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700690 spin_unlock_irqrestore(&zone->lru_lock,
691 flags);
Nick Piggin46453a62006-03-22 00:07:58 -0800692 zone = pagezone;
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700693 spin_lock_irqsave(&zone->lru_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700694 }
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700695
696 lruvec = mem_cgroup_page_lruvec(page, zone);
Nick Piggin725d7042006-09-25 23:30:55 -0700697 VM_BUG_ON(!PageLRU(page));
Nick Piggin67453912006-03-22 00:08:00 -0800698 __ClearPageLRU(page);
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700699 del_page_from_lru_list(page, lruvec, page_off_lru(page));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700700 }
Nick Piggin46453a62006-03-22 00:07:58 -0800701
Konstantin Khlebnikovcc598502012-01-10 15:07:04 -0800702 list_add(&page->lru, &pages_to_free);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700703 }
704 if (zone)
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700705 spin_unlock_irqrestore(&zone->lru_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700706
Konstantin Khlebnikovcc598502012-01-10 15:07:04 -0800707 free_hot_cold_page_list(&pages_to_free, cold);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700708}
Miklos Szeredi0be85572010-10-27 15:34:46 -0700709EXPORT_SYMBOL(release_pages);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700710
711/*
712 * The pages which we're about to release may be in the deferred lru-addition
713 * queues. That would prevent them from really being freed right now. That's
714 * OK from a correctness point of view but is inefficient - those pages may be
715 * cache-warm and we want to give them back to the page allocator ASAP.
716 *
717 * So __pagevec_release() will drain those queues here. __pagevec_lru_add()
718 * and __pagevec_lru_add_active() call release_pages() directly to avoid
719 * mutual recursion.
720 */
721void __pagevec_release(struct pagevec *pvec)
722{
723 lru_add_drain();
724 release_pages(pvec->pages, pagevec_count(pvec), pvec->cold);
725 pagevec_reinit(pvec);
726}
Steve French7f285702005-11-01 10:22:55 -0800727EXPORT_SYMBOL(__pagevec_release);
728
Hugh Dickins12d27102012-01-12 17:19:52 -0800729#ifdef CONFIG_TRANSPARENT_HUGEPAGE
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800730/* used by __split_huge_page_refcount() */
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700731void lru_add_page_tail(struct page *page, struct page *page_tail,
732 struct lruvec *lruvec)
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800733{
Hugh Dickins75121022012-03-05 14:59:18 -0800734 int uninitialized_var(active);
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800735 enum lru_list lru;
736 const int file = 0;
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800737
738 VM_BUG_ON(!PageHead(page));
739 VM_BUG_ON(PageCompound(page_tail));
740 VM_BUG_ON(PageLRU(page_tail));
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700741 VM_BUG_ON(NR_CPUS != 1 &&
742 !spin_is_locked(&lruvec_zone(lruvec)->lru_lock));
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800743
744 SetPageLRU(page_tail);
745
746 if (page_evictable(page_tail, NULL)) {
747 if (PageActive(page)) {
748 SetPageActive(page_tail);
749 active = 1;
750 lru = LRU_ACTIVE_ANON;
751 } else {
752 active = 0;
753 lru = LRU_INACTIVE_ANON;
754 }
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800755 } else {
756 SetPageUnevictable(page_tail);
Hugh Dickins12d27102012-01-12 17:19:52 -0800757 lru = LRU_UNEVICTABLE;
758 }
759
760 if (likely(PageLRU(page)))
761 list_add_tail(&page_tail->lru, &page->lru);
762 else {
763 struct list_head *list_head;
764 /*
765 * Head page has not yet been counted, as an hpage,
766 * so we must account for each subpage individually.
767 *
768 * Use the standard add function to put page_tail on the list,
769 * but then correct its position so they all end up in order.
770 */
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700771 add_page_to_lru_list(page_tail, lruvec, lru);
Hugh Dickins12d27102012-01-12 17:19:52 -0800772 list_head = page_tail->lru.prev;
773 list_move_tail(&page_tail->lru, list_head);
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800774 }
Hugh Dickins75121022012-03-05 14:59:18 -0800775
776 if (!PageUnevictable(page))
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700777 update_page_reclaim_stat(lruvec, file, active);
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800778}
Hugh Dickins12d27102012-01-12 17:19:52 -0800779#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800780
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700781static void __pagevec_lru_add_fn(struct page *page, struct lruvec *lruvec,
782 void *arg)
Shaohua Li3dd7ae82011-03-22 16:33:45 -0700783{
784 enum lru_list lru = (enum lru_list)arg;
Shaohua Li3dd7ae82011-03-22 16:33:45 -0700785 int file = is_file_lru(lru);
786 int active = is_active_lru(lru);
787
788 VM_BUG_ON(PageActive(page));
789 VM_BUG_ON(PageUnevictable(page));
790 VM_BUG_ON(PageLRU(page));
791
792 SetPageLRU(page);
793 if (active)
794 SetPageActive(page);
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700795 add_page_to_lru_list(page, lruvec, lru);
796 update_page_reclaim_stat(lruvec, file, active);
Shaohua Li3dd7ae82011-03-22 16:33:45 -0700797}
798
Linus Torvalds1da177e2005-04-16 15:20:36 -0700799/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700800 * Add the passed pages to the LRU, then drop the caller's refcount
801 * on them. Reinitialises the caller's pagevec.
802 */
Hugh Dickins5095ae832012-01-12 17:19:58 -0800803void __pagevec_lru_add(struct pagevec *pvec, enum lru_list lru)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700804{
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700805 VM_BUG_ON(is_unevictable_lru(lru));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700806
Hugh Dickins5095ae832012-01-12 17:19:58 -0800807 pagevec_lru_move_fn(pvec, __pagevec_lru_add_fn, (void *)lru);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700808}
Hugh Dickins5095ae832012-01-12 17:19:58 -0800809EXPORT_SYMBOL(__pagevec_lru_add);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700810
Linus Torvalds1da177e2005-04-16 15:20:36 -0700811/**
812 * pagevec_lookup - gang pagecache lookup
813 * @pvec: Where the resulting pages are placed
814 * @mapping: The address_space to search
815 * @start: The starting page index
816 * @nr_pages: The maximum number of pages
817 *
818 * pagevec_lookup() will search for and return a group of up to @nr_pages pages
819 * in the mapping. The pages are placed in @pvec. pagevec_lookup() takes a
820 * reference against the pages in @pvec.
821 *
822 * The search returns a group of mapping-contiguous pages with ascending
823 * indexes. There may be holes in the indices due to not-present pages.
824 *
825 * pagevec_lookup() returns the number of pages which were found.
826 */
827unsigned pagevec_lookup(struct pagevec *pvec, struct address_space *mapping,
828 pgoff_t start, unsigned nr_pages)
829{
830 pvec->nr = find_get_pages(mapping, start, nr_pages, pvec->pages);
831 return pagevec_count(pvec);
832}
Christoph Hellwig78539fd2006-01-11 20:47:41 +1100833EXPORT_SYMBOL(pagevec_lookup);
834
Linus Torvalds1da177e2005-04-16 15:20:36 -0700835unsigned pagevec_lookup_tag(struct pagevec *pvec, struct address_space *mapping,
836 pgoff_t *index, int tag, unsigned nr_pages)
837{
838 pvec->nr = find_get_pages_tag(mapping, index, tag,
839 nr_pages, pvec->pages);
840 return pagevec_count(pvec);
841}
Steve French7f285702005-11-01 10:22:55 -0800842EXPORT_SYMBOL(pagevec_lookup_tag);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700843
Linus Torvalds1da177e2005-04-16 15:20:36 -0700844/*
845 * Perform any setup for the swap system
846 */
847void __init swap_setup(void)
848{
Jan Beulich44813742009-09-21 17:03:05 -0700849 unsigned long megs = totalram_pages >> (20 - PAGE_SHIFT);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700850
Peter Zijlstrae0bf68d2007-10-16 23:25:46 -0700851#ifdef CONFIG_SWAP
852 bdi_init(swapper_space.backing_dev_info);
853#endif
854
Linus Torvalds1da177e2005-04-16 15:20:36 -0700855 /* Use a smaller cluster for small-memory machines */
856 if (megs < 16)
857 page_cluster = 2;
858 else
859 page_cluster = 3;
860 /*
861 * Right now other parts of the system means that we
862 * _really_ don't want to cluster much more
863 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700864}