blob: 7434e3619c14108181dab183b8c532d6bddecec0 [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>
Kent Overstreeta27bb332013-05-07 16:19:08 -070033#include <linux/uio.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070034
Lee Schermerhorn64d65192008-10-18 20:26:52 -070035#include "internal.h"
36
Mel Gormanc6286c92013-07-03 15:02:26 -070037#define CREATE_TRACE_POINTS
38#include <trace/events/pagemap.h>
39
Linus Torvalds1da177e2005-04-16 15:20:36 -070040/* How many pages do we try to swap or page in/out together? */
41int page_cluster;
42
Mel Gorman13f7f782013-07-03 15:02:28 -070043static DEFINE_PER_CPU(struct pagevec, lru_add_pvec);
Vegard Nossumf84f95042008-07-23 21:28:14 -070044static DEFINE_PER_CPU(struct pagevec, lru_rotate_pvecs);
Minchan Kim31560182011-03-22 16:32:52 -070045static DEFINE_PER_CPU(struct pagevec, lru_deactivate_pvecs);
Hisashi Hifumi902aaed2007-10-16 01:24:52 -070046
Adrian Bunkb2213852006-09-25 23:31:02 -070047/*
48 * This path almost never happens for VM activity - pages are normally
49 * freed via pagevecs. But it gets used by networking.
50 */
Harvey Harrison920c7a52008-02-04 22:29:26 -080051static void __page_cache_release(struct page *page)
Adrian Bunkb2213852006-09-25 23:31:02 -070052{
53 if (PageLRU(page)) {
Adrian Bunkb2213852006-09-25 23:31:02 -070054 struct zone *zone = page_zone(page);
Hugh Dickinsfa9add62012-05-29 15:07:09 -070055 struct lruvec *lruvec;
56 unsigned long flags;
Adrian Bunkb2213852006-09-25 23:31:02 -070057
58 spin_lock_irqsave(&zone->lru_lock, flags);
Hugh Dickinsfa9add62012-05-29 15:07:09 -070059 lruvec = mem_cgroup_page_lruvec(page, zone);
Adrian Bunkb2213852006-09-25 23:31:02 -070060 VM_BUG_ON(!PageLRU(page));
61 __ClearPageLRU(page);
Hugh Dickinsfa9add62012-05-29 15:07:09 -070062 del_page_from_lru_list(page, lruvec, page_off_lru(page));
Adrian Bunkb2213852006-09-25 23:31:02 -070063 spin_unlock_irqrestore(&zone->lru_lock, flags);
64 }
Andrea Arcangeli91807062011-01-13 15:46:32 -080065}
66
67static void __put_single_page(struct page *page)
68{
69 __page_cache_release(page);
Li Hongfc916682010-03-05 13:41:54 -080070 free_hot_cold_page(page, 0);
Adrian Bunkb2213852006-09-25 23:31:02 -070071}
72
Andrea Arcangeli91807062011-01-13 15:46:32 -080073static void __put_compound_page(struct page *page)
74{
75 compound_page_dtor *dtor;
76
77 __page_cache_release(page);
78 dtor = get_compound_page_dtor(page);
79 (*dtor)(page);
80}
81
Nick Piggin8519fb32006-02-07 12:58:52 -080082static void put_compound_page(struct page *page)
83{
Andrea Arcangeli91807062011-01-13 15:46:32 -080084 if (unlikely(PageTail(page))) {
85 /* __split_huge_page_refcount can run under us */
Andrea Arcangeli70b50f92011-11-02 13:36:59 -070086 struct page *page_head = compound_trans_head(page);
87
Andrea Arcangeliebf360f2014-01-21 15:48:51 -080088 /*
89 * THP can not break up slab pages so avoid taking
Andrea Arcangeli44518d22014-01-21 15:48:54 -080090 * compound_lock() and skip the tail page refcounting
91 * (in _mapcount) too. Slab performs non-atomic bit
92 * ops on page->flags for better performance. In
Andrea Arcangeliebf360f2014-01-21 15:48:51 -080093 * particular slab_unlock() in slub used to be a hot
94 * path. It is still hot on arches that do not support
95 * this_cpu_cmpxchg_double().
96 *
97 * If "page" is part of a slab or hugetlbfs page it
98 * cannot be splitted and the head page cannot change
99 * from under us. And if "page" is part of a THP page
100 * under splitting, if the head page pointed by the
101 * THP tail isn't a THP head anymore, we'll find
102 * PageTail clear after smp_rmb() and we'll treat it
103 * as a single page.
104 */
Andrea Arcangeli44518d22014-01-21 15:48:54 -0800105 if (!__compound_tail_refcounted(page_head)) {
Andrea Arcangeliebf360f2014-01-21 15:48:51 -0800106 /*
107 * If "page" is a THP tail, we must read the tail page
108 * flags after the head page flags. The
109 * split_huge_page side enforces write memory
110 * barriers between clearing PageTail and before the
111 * head page can be freed and reallocated.
112 */
113 smp_rmb();
114 if (likely(PageTail(page))) {
115 /*
116 * __split_huge_page_refcount
117 * cannot race here.
118 */
119 VM_BUG_ON(!PageHead(page_head));
Andrea Arcangeli44518d22014-01-21 15:48:54 -0800120 VM_BUG_ON(page_mapcount(page) != 0);
121 if (put_page_testzero(page_head)) {
122 /*
123 * If this is the tail of a
124 * slab compound page, the
125 * tail pin must not be the
126 * last reference held on the
127 * page, because the PG_slab
128 * cannot be cleared before
129 * all tail pins (which skips
130 * the _mapcount tail
131 * refcounting) have been
132 * released. For hugetlbfs the
133 * tail pin may be the last
134 * reference on the page
135 * instead, because
136 * PageHeadHuge will not go
137 * away until the compound
138 * page enters the buddy
139 * allocator.
140 */
141 VM_BUG_ON(PageSlab(page_head));
Andrea Arcangeliebf360f2014-01-21 15:48:51 -0800142 __put_compound_page(page_head);
Andrea Arcangeli44518d22014-01-21 15:48:54 -0800143 }
Andrea Arcangeliebf360f2014-01-21 15:48:51 -0800144 return;
145 } else
146 /*
147 * __split_huge_page_refcount
148 * run before us, "page" was a
149 * THP tail. The split
150 * page_head has been freed
151 * and reallocated as slab or
152 * hugetlbfs page of smaller
153 * order (only possible if
154 * reallocated as slab on
155 * x86).
156 */
157 goto out_put_single;
158 }
159
Andrea Arcangeli70b50f92011-11-02 13:36:59 -0700160 if (likely(page != page_head &&
161 get_page_unless_zero(page_head))) {
Andrea Arcangeli91807062011-01-13 15:46:32 -0800162 unsigned long flags;
Pravin B Shelar5bf5f032012-05-29 15:06:49 -0700163
164 /*
Andrea Arcangeli70b50f92011-11-02 13:36:59 -0700165 * page_head wasn't a dangling pointer but it
166 * may not be a head page anymore by the time
167 * we obtain the lock. That is ok as long as it
168 * can't be freed from under us.
Andrea Arcangeli91807062011-01-13 15:46:32 -0800169 */
Andrea Arcangeli91807062011-01-13 15:46:32 -0800170 flags = compound_lock_irqsave(page_head);
171 if (unlikely(!PageTail(page))) {
172 /* __split_huge_page_refcount run before us */
173 compound_unlock_irqrestore(page_head, flags);
Andrea Arcangeli27c73ae2013-11-21 14:32:02 -0800174 if (put_page_testzero(page_head)) {
175 /*
176 * The head page may have been
177 * freed and reallocated as a
178 * compound page of smaller
179 * order and then freed again.
180 * All we know is that it
181 * cannot have become: a THP
182 * page, a compound page of
183 * higher order, a tail page.
184 * That is because we still
185 * hold the refcount of the
186 * split THP tail and
187 * page_head was the THP head
188 * before the split.
189 */
190 if (PageHead(page_head))
191 __put_compound_page(page_head);
192 else
193 __put_single_page(page_head);
194 }
Pravin B Shelar5bf5f032012-05-29 15:06:49 -0700195out_put_single:
Andrea Arcangeli91807062011-01-13 15:46:32 -0800196 if (put_page_testzero(page))
197 __put_single_page(page);
198 return;
199 }
200 VM_BUG_ON(page_head != page->first_page);
201 /*
202 * We can release the refcount taken by
Andrea Arcangeli70b50f92011-11-02 13:36:59 -0700203 * get_page_unless_zero() now that
204 * __split_huge_page_refcount() is blocked on
205 * the compound_lock.
Andrea Arcangeli91807062011-01-13 15:46:32 -0800206 */
207 if (put_page_testzero(page_head))
208 VM_BUG_ON(1);
209 /* __split_huge_page_refcount will wait now */
Andrea Arcangeli70b50f92011-11-02 13:36:59 -0700210 VM_BUG_ON(page_mapcount(page) <= 0);
211 atomic_dec(&page->_mapcount);
Andrea Arcangeli91807062011-01-13 15:46:32 -0800212 VM_BUG_ON(atomic_read(&page_head->_count) <= 0);
Andrea Arcangeli70b50f92011-11-02 13:36:59 -0700213 VM_BUG_ON(atomic_read(&page->_count) != 0);
Andrea Arcangeli91807062011-01-13 15:46:32 -0800214 compound_unlock_irqrestore(page_head, flags);
Pravin B Shelar5bf5f032012-05-29 15:06:49 -0700215
Andrea Arcangelia95a82e2011-01-13 15:46:33 -0800216 if (put_page_testzero(page_head)) {
217 if (PageHead(page_head))
218 __put_compound_page(page_head);
219 else
220 __put_single_page(page_head);
221 }
Andrea Arcangeli91807062011-01-13 15:46:32 -0800222 } else {
223 /* page_head is a dangling pointer */
224 VM_BUG_ON(PageTail(page));
225 goto out_put_single;
226 }
227 } else if (put_page_testzero(page)) {
228 if (PageHead(page))
229 __put_compound_page(page);
230 else
231 __put_single_page(page);
Nick Piggin8519fb32006-02-07 12:58:52 -0800232 }
233}
234
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235void put_page(struct page *page)
236{
Nick Piggin8519fb32006-02-07 12:58:52 -0800237 if (unlikely(PageCompound(page)))
238 put_compound_page(page);
239 else if (put_page_testzero(page))
Andrea Arcangeli91807062011-01-13 15:46:32 -0800240 __put_single_page(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700241}
242EXPORT_SYMBOL(put_page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700243
Andrea Arcangeli70b50f92011-11-02 13:36:59 -0700244/*
245 * This function is exported but must not be called by anything other
246 * than get_page(). It implements the slow path of get_page().
247 */
248bool __get_page_tail(struct page *page)
249{
250 /*
251 * This takes care of get_page() if run on a tail page
252 * returned by one of the get_user_pages/follow_page variants.
253 * get_user_pages/follow_page itself doesn't need the compound
254 * lock because it runs __get_page_tail_foll() under the
255 * proper PT lock that already serializes against
256 * split_huge_page().
257 */
Andrea Arcangeli27c73ae2013-11-21 14:32:02 -0800258 unsigned long flags;
Andrea Arcangeliebf360f2014-01-21 15:48:51 -0800259 bool got;
Andrea Arcangeli27c73ae2013-11-21 14:32:02 -0800260 struct page *page_head = compound_trans_head(page);
Andrea Arcangeli70b50f92011-11-02 13:36:59 -0700261
Andrea Arcangeliebf360f2014-01-21 15:48:51 -0800262 /* Ref to put_compound_page() comment. */
Andrea Arcangeli3bfcd132014-01-21 15:48:56 -0800263 if (!__compound_tail_refcounted(page_head)) {
Andrea Arcangeliebf360f2014-01-21 15:48:51 -0800264 smp_rmb();
265 if (likely(PageTail(page))) {
266 /*
267 * This is a hugetlbfs page or a slab
268 * page. __split_huge_page_refcount
269 * cannot race here.
270 */
271 VM_BUG_ON(!PageHead(page_head));
272 __get_page_tail_foll(page, true);
273 return true;
274 } else {
275 /*
276 * __split_huge_page_refcount run
277 * before us, "page" was a THP
278 * tail. The split page_head has been
279 * freed and reallocated as slab or
280 * hugetlbfs page of smaller order
281 * (only possible if reallocated as
282 * slab on x86).
283 */
284 return false;
Pravin B Shelar5bf5f032012-05-29 15:06:49 -0700285 }
Andrea Arcangeliebf360f2014-01-21 15:48:51 -0800286 }
Andrea Arcangeli27c73ae2013-11-21 14:32:02 -0800287
Andrea Arcangeliebf360f2014-01-21 15:48:51 -0800288 got = false;
289 if (likely(page != page_head && get_page_unless_zero(page_head))) {
Andrea Arcangeli27c73ae2013-11-21 14:32:02 -0800290 /*
291 * page_head wasn't a dangling pointer but it
292 * may not be a head page anymore by the time
293 * we obtain the lock. That is ok as long as it
294 * can't be freed from under us.
295 */
296 flags = compound_lock_irqsave(page_head);
297 /* here __split_huge_page_refcount won't run anymore */
298 if (likely(PageTail(page))) {
299 __get_page_tail_foll(page, false);
300 got = true;
301 }
302 compound_unlock_irqrestore(page_head, flags);
303 if (unlikely(!got))
304 put_page(page_head);
Andrea Arcangeli70b50f92011-11-02 13:36:59 -0700305 }
306 return got;
307}
308EXPORT_SYMBOL(__get_page_tail);
309
Alexander Zarochentsev1d7ea732006-08-13 23:24:27 -0700310/**
Randy Dunlap76824862008-03-19 17:00:40 -0700311 * put_pages_list() - release a list of pages
312 * @pages: list of pages threaded on page->lru
Alexander Zarochentsev1d7ea732006-08-13 23:24:27 -0700313 *
314 * Release a list of pages which are strung together on page.lru. Currently
315 * used by read_cache_pages() and related error recovery code.
Alexander Zarochentsev1d7ea732006-08-13 23:24:27 -0700316 */
317void put_pages_list(struct list_head *pages)
318{
319 while (!list_empty(pages)) {
320 struct page *victim;
321
322 victim = list_entry(pages->prev, struct page, lru);
323 list_del(&victim->lru);
324 page_cache_release(victim);
325 }
326}
327EXPORT_SYMBOL(put_pages_list);
328
Mel Gorman18022c52012-07-31 16:44:51 -0700329/*
330 * get_kernel_pages() - pin kernel pages in memory
331 * @kiov: An array of struct kvec structures
332 * @nr_segs: number of segments to pin
333 * @write: pinning for read/write, currently ignored
334 * @pages: array that receives pointers to the pages pinned.
335 * Should be at least nr_segs long.
336 *
337 * Returns number of pages pinned. This may be fewer than the number
338 * requested. If nr_pages is 0 or negative, returns 0. If no pages
339 * were pinned, returns -errno. Each page returned must be released
340 * with a put_page() call when it is finished with.
341 */
342int get_kernel_pages(const struct kvec *kiov, int nr_segs, int write,
343 struct page **pages)
344{
345 int seg;
346
347 for (seg = 0; seg < nr_segs; seg++) {
348 if (WARN_ON(kiov[seg].iov_len != PAGE_SIZE))
349 return seg;
350
Mel Gorman5a178112012-07-31 16:45:02 -0700351 pages[seg] = kmap_to_page(kiov[seg].iov_base);
Mel Gorman18022c52012-07-31 16:44:51 -0700352 page_cache_get(pages[seg]);
353 }
354
355 return seg;
356}
357EXPORT_SYMBOL_GPL(get_kernel_pages);
358
359/*
360 * get_kernel_page() - pin a kernel page in memory
361 * @start: starting kernel address
362 * @write: pinning for read/write, currently ignored
363 * @pages: array that receives pointer to the page pinned.
364 * Must be at least nr_segs long.
365 *
366 * Returns 1 if page is pinned. If the page was not pinned, returns
367 * -errno. The page returned must be released with a put_page() call
368 * when it is finished with.
369 */
370int get_kernel_page(unsigned long start, int write, struct page **pages)
371{
372 const struct kvec kiov = {
373 .iov_base = (void *)start,
374 .iov_len = PAGE_SIZE
375 };
376
377 return get_kernel_pages(&kiov, 1, write, pages);
378}
379EXPORT_SYMBOL_GPL(get_kernel_page);
380
Shaohua Li3dd7ae82011-03-22 16:33:45 -0700381static void pagevec_lru_move_fn(struct pagevec *pvec,
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700382 void (*move_fn)(struct page *page, struct lruvec *lruvec, void *arg),
383 void *arg)
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700384{
385 int i;
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700386 struct zone *zone = NULL;
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700387 struct lruvec *lruvec;
Shaohua Li3dd7ae82011-03-22 16:33:45 -0700388 unsigned long flags = 0;
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700389
390 for (i = 0; i < pagevec_count(pvec); i++) {
391 struct page *page = pvec->pages[i];
392 struct zone *pagezone = page_zone(page);
393
394 if (pagezone != zone) {
395 if (zone)
Shaohua Li3dd7ae82011-03-22 16:33:45 -0700396 spin_unlock_irqrestore(&zone->lru_lock, flags);
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700397 zone = pagezone;
Shaohua Li3dd7ae82011-03-22 16:33:45 -0700398 spin_lock_irqsave(&zone->lru_lock, flags);
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700399 }
Shaohua Li3dd7ae82011-03-22 16:33:45 -0700400
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700401 lruvec = mem_cgroup_page_lruvec(page, zone);
402 (*move_fn)(page, lruvec, arg);
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700403 }
404 if (zone)
Shaohua Li3dd7ae82011-03-22 16:33:45 -0700405 spin_unlock_irqrestore(&zone->lru_lock, flags);
Linus Torvalds83896fb2011-01-17 14:42:34 -0800406 release_pages(pvec->pages, pvec->nr, pvec->cold);
407 pagevec_reinit(pvec);
Shaohua Lid8505de2011-01-13 15:47:33 -0800408}
409
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700410static void pagevec_move_tail_fn(struct page *page, struct lruvec *lruvec,
411 void *arg)
Shaohua Li3dd7ae82011-03-22 16:33:45 -0700412{
413 int *pgmoved = arg;
Shaohua Li3dd7ae82011-03-22 16:33:45 -0700414
415 if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) {
416 enum lru_list lru = page_lru_base_type(page);
Johannes Weiner925b7672012-01-12 17:18:15 -0800417 list_move_tail(&page->lru, &lruvec->lists[lru]);
Shaohua Li3dd7ae82011-03-22 16:33:45 -0700418 (*pgmoved)++;
419 }
420}
421
422/*
423 * pagevec_move_tail() must be called with IRQ disabled.
424 * Otherwise this may cause nasty races.
425 */
426static void pagevec_move_tail(struct pagevec *pvec)
427{
428 int pgmoved = 0;
429
430 pagevec_lru_move_fn(pvec, pagevec_move_tail_fn, &pgmoved);
431 __count_vm_events(PGROTATED, pgmoved);
432}
433
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700434/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700435 * Writeback is about to end against a page which has been marked for immediate
436 * reclaim. If it still appears to be reclaimable, move it to the tail of the
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700437 * inactive list.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700438 */
Shaohua Li3dd7ae82011-03-22 16:33:45 -0700439void rotate_reclaimable_page(struct page *page)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700440{
Miklos Szerediac6aadb2008-04-28 02:12:38 -0700441 if (!PageLocked(page) && !PageDirty(page) && !PageActive(page) &&
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700442 !PageUnevictable(page) && PageLRU(page)) {
Miklos Szerediac6aadb2008-04-28 02:12:38 -0700443 struct pagevec *pvec;
444 unsigned long flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700445
Miklos Szerediac6aadb2008-04-28 02:12:38 -0700446 page_cache_get(page);
447 local_irq_save(flags);
448 pvec = &__get_cpu_var(lru_rotate_pvecs);
449 if (!pagevec_add(pvec, page))
450 pagevec_move_tail(pvec);
451 local_irq_restore(flags);
452 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700453}
454
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700455static void update_page_reclaim_stat(struct lruvec *lruvec,
KOSAKI Motohiro3e2f41f2009-01-07 18:08:20 -0800456 int file, int rotated)
457{
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700458 struct zone_reclaim_stat *reclaim_stat = &lruvec->reclaim_stat;
KOSAKI Motohiro3e2f41f2009-01-07 18:08:20 -0800459
460 reclaim_stat->recent_scanned[file]++;
461 if (rotated)
462 reclaim_stat->recent_rotated[file]++;
KOSAKI Motohiro3e2f41f2009-01-07 18:08:20 -0800463}
464
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700465static void __activate_page(struct page *page, struct lruvec *lruvec,
466 void *arg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700467{
Linus Torvalds7a608572011-01-17 14:42:19 -0800468 if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) {
469 int file = page_is_file_cache(page);
470 int lru = page_lru_base_type(page);
Linus Torvalds7a608572011-01-17 14:42:19 -0800471
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700472 del_page_from_lru_list(page, lruvec, lru);
Linus Torvalds7a608572011-01-17 14:42:19 -0800473 SetPageActive(page);
474 lru += LRU_ACTIVE;
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700475 add_page_to_lru_list(page, lruvec, lru);
Mel Gormanc6286c92013-07-03 15:02:26 -0700476 trace_mm_lru_activate(page, page_to_pfn(page));
Linus Torvalds7a608572011-01-17 14:42:19 -0800477
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700478 __count_vm_event(PGACTIVATE);
479 update_page_reclaim_stat(lruvec, file, 1);
Linus Torvalds7a608572011-01-17 14:42:19 -0800480 }
Shaohua Lieb709b02011-05-24 17:12:55 -0700481}
482
483#ifdef CONFIG_SMP
484static DEFINE_PER_CPU(struct pagevec, activate_page_pvecs);
485
486static void activate_page_drain(int cpu)
487{
488 struct pagevec *pvec = &per_cpu(activate_page_pvecs, cpu);
489
490 if (pagevec_count(pvec))
491 pagevec_lru_move_fn(pvec, __activate_page, NULL);
492}
493
Chris Metcalf5fbc4612013-09-12 15:13:55 -0700494static bool need_activate_page_drain(int cpu)
495{
496 return pagevec_count(&per_cpu(activate_page_pvecs, cpu)) != 0;
497}
498
Shaohua Lieb709b02011-05-24 17:12:55 -0700499void activate_page(struct page *page)
500{
501 if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) {
502 struct pagevec *pvec = &get_cpu_var(activate_page_pvecs);
503
504 page_cache_get(page);
505 if (!pagevec_add(pvec, page))
506 pagevec_lru_move_fn(pvec, __activate_page, NULL);
507 put_cpu_var(activate_page_pvecs);
508 }
509}
510
511#else
512static inline void activate_page_drain(int cpu)
513{
514}
515
Chris Metcalf5fbc4612013-09-12 15:13:55 -0700516static bool need_activate_page_drain(int cpu)
517{
518 return false;
519}
520
Shaohua Lieb709b02011-05-24 17:12:55 -0700521void activate_page(struct page *page)
522{
523 struct zone *zone = page_zone(page);
524
525 spin_lock_irq(&zone->lru_lock);
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700526 __activate_page(page, mem_cgroup_page_lruvec(page, zone), NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700527 spin_unlock_irq(&zone->lru_lock);
528}
Shaohua Lieb709b02011-05-24 17:12:55 -0700529#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700530
Mel Gorman059285a2013-07-03 15:02:30 -0700531static void __lru_cache_activate_page(struct page *page)
532{
533 struct pagevec *pvec = &get_cpu_var(lru_add_pvec);
534 int i;
535
536 /*
537 * Search backwards on the optimistic assumption that the page being
538 * activated has just been added to this pagevec. Note that only
539 * the local pagevec is examined as a !PageLRU page could be in the
540 * process of being released, reclaimed, migrated or on a remote
541 * pagevec that is currently being drained. Furthermore, marking
542 * a remote pagevec's page PageActive potentially hits a race where
543 * a page is marked PageActive just after it is added to the inactive
544 * list causing accounting errors and BUG_ON checks to trigger.
545 */
546 for (i = pagevec_count(pvec) - 1; i >= 0; i--) {
547 struct page *pagevec_page = pvec->pages[i];
548
549 if (pagevec_page == page) {
550 SetPageActive(page);
551 break;
552 }
553 }
554
555 put_cpu_var(lru_add_pvec);
556}
557
Linus Torvalds1da177e2005-04-16 15:20:36 -0700558/*
559 * Mark a page as having seen activity.
560 *
561 * inactive,unreferenced -> inactive,referenced
562 * inactive,referenced -> active,unreferenced
563 * active,unreferenced -> active,referenced
564 */
Harvey Harrison920c7a52008-02-04 22:29:26 -0800565void mark_page_accessed(struct page *page)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700566{
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700567 if (!PageActive(page) && !PageUnevictable(page) &&
Mel Gorman059285a2013-07-03 15:02:30 -0700568 PageReferenced(page)) {
569
570 /*
571 * If the page is on the LRU, queue it for activation via
572 * activate_page_pvecs. Otherwise, assume the page is on a
573 * pagevec, mark it active and it'll be moved to the active
574 * LRU on the next drain.
575 */
576 if (PageLRU(page))
577 activate_page(page);
578 else
579 __lru_cache_activate_page(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700580 ClearPageReferenced(page);
581 } else if (!PageReferenced(page)) {
582 SetPageReferenced(page);
583 }
584}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700585EXPORT_SYMBOL(mark_page_accessed);
586
Robin Dongd741c9c2012-10-08 16:29:05 -0700587/*
Mel Gorman13f7f782013-07-03 15:02:28 -0700588 * Queue the page for addition to the LRU via pagevec. The decision on whether
589 * to add the page to the [in]active [file|anon] list is deferred until the
590 * pagevec is drained. This gives a chance for the caller of __lru_cache_add()
591 * have the page added to the active list using mark_page_accessed().
Robin Dongd741c9c2012-10-08 16:29:05 -0700592 */
Mel Gormanc53954a2013-07-03 15:02:34 -0700593void __lru_cache_add(struct page *page)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700594{
Mel Gorman13f7f782013-07-03 15:02:28 -0700595 struct pagevec *pvec = &get_cpu_var(lru_add_pvec);
596
Linus Torvalds1da177e2005-04-16 15:20:36 -0700597 page_cache_get(page);
Robin Dongd741c9c2012-10-08 16:29:05 -0700598 if (!pagevec_space(pvec))
Mel Gormana0b8cab32013-07-03 15:02:32 -0700599 __pagevec_lru_add(pvec);
Robin Dongd741c9c2012-10-08 16:29:05 -0700600 pagevec_add(pvec, page);
Mel Gorman13f7f782013-07-03 15:02:28 -0700601 put_cpu_var(lru_add_pvec);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700602}
Miklos Szeredi47846b02010-05-25 15:06:06 +0200603EXPORT_SYMBOL(__lru_cache_add);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700604
KOSAKI Motohirof04e9eb2008-10-18 20:26:19 -0700605/**
Mel Gormanc53954a2013-07-03 15:02:34 -0700606 * lru_cache_add - add a page to a page list
KOSAKI Motohirof04e9eb2008-10-18 20:26:19 -0700607 * @page: the page to be added to the LRU.
KOSAKI Motohirof04e9eb2008-10-18 20:26:19 -0700608 */
Mel Gormanc53954a2013-07-03 15:02:34 -0700609void lru_cache_add(struct page *page)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700610{
Naoya Horiguchief2a2cb2013-07-31 13:53:37 -0700611 VM_BUG_ON(PageActive(page) && PageUnevictable(page));
Mel Gorman13f7f782013-07-03 15:02:28 -0700612 VM_BUG_ON(PageLRU(page));
Mel Gormanc53954a2013-07-03 15:02:34 -0700613 __lru_cache_add(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700614}
615
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700616/**
617 * add_page_to_unevictable_list - add a page to the unevictable list
618 * @page: the page to be added to the unevictable list
619 *
620 * Add page directly to its zone's unevictable list. To avoid races with
621 * tasks that might be making the page evictable, through eg. munlock,
622 * munmap or exit, while it's not on the lru, we want to add the page
623 * while it's locked or otherwise "invisible" to other tasks. This is
624 * difficult to do when using the pagevec cache, so bypass that.
625 */
626void add_page_to_unevictable_list(struct page *page)
627{
628 struct zone *zone = page_zone(page);
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700629 struct lruvec *lruvec;
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700630
631 spin_lock_irq(&zone->lru_lock);
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700632 lruvec = mem_cgroup_page_lruvec(page, zone);
Naoya Horiguchief2a2cb2013-07-31 13:53:37 -0700633 ClearPageActive(page);
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700634 SetPageUnevictable(page);
635 SetPageLRU(page);
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700636 add_page_to_lru_list(page, lruvec, LRU_UNEVICTABLE);
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700637 spin_unlock_irq(&zone->lru_lock);
638}
639
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700640/*
Minchan Kim31560182011-03-22 16:32:52 -0700641 * If the page can not be invalidated, it is moved to the
642 * inactive list to speed up its reclaim. It is moved to the
643 * head of the list, rather than the tail, to give the flusher
644 * threads some time to write it out, as this is much more
645 * effective than the single-page writeout from reclaim.
Minchan Kim278df9f2011-03-22 16:32:54 -0700646 *
647 * If the page isn't page_mapped and dirty/writeback, the page
648 * could reclaim asap using PG_reclaim.
649 *
650 * 1. active, mapped page -> none
651 * 2. active, dirty/writeback page -> inactive, head, PG_reclaim
652 * 3. inactive, mapped page -> none
653 * 4. inactive, dirty/writeback page -> inactive, head, PG_reclaim
654 * 5. inactive, clean -> inactive, tail
655 * 6. Others -> none
656 *
657 * In 4, why it moves inactive's head, the VM expects the page would
658 * be write it out by flusher threads as this is much more effective
659 * than the single-page writeout from reclaim.
Minchan Kim31560182011-03-22 16:32:52 -0700660 */
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700661static void lru_deactivate_fn(struct page *page, struct lruvec *lruvec,
662 void *arg)
Minchan Kim31560182011-03-22 16:32:52 -0700663{
664 int lru, file;
Minchan Kim278df9f2011-03-22 16:32:54 -0700665 bool active;
Minchan Kim31560182011-03-22 16:32:52 -0700666
Minchan Kim278df9f2011-03-22 16:32:54 -0700667 if (!PageLRU(page))
Minchan Kim31560182011-03-22 16:32:52 -0700668 return;
669
Minchan Kimbad49d92011-05-11 15:13:30 -0700670 if (PageUnevictable(page))
671 return;
672
Minchan Kim31560182011-03-22 16:32:52 -0700673 /* Some processes are using the page */
674 if (page_mapped(page))
675 return;
676
Minchan Kim278df9f2011-03-22 16:32:54 -0700677 active = PageActive(page);
Minchan Kim31560182011-03-22 16:32:52 -0700678 file = page_is_file_cache(page);
679 lru = page_lru_base_type(page);
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700680
681 del_page_from_lru_list(page, lruvec, lru + active);
Minchan Kim31560182011-03-22 16:32:52 -0700682 ClearPageActive(page);
683 ClearPageReferenced(page);
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700684 add_page_to_lru_list(page, lruvec, lru);
Minchan Kim31560182011-03-22 16:32:52 -0700685
Minchan Kim278df9f2011-03-22 16:32:54 -0700686 if (PageWriteback(page) || PageDirty(page)) {
687 /*
688 * PG_reclaim could be raced with end_page_writeback
689 * It can make readahead confusing. But race window
690 * is _really_ small and it's non-critical problem.
691 */
692 SetPageReclaim(page);
693 } else {
694 /*
695 * The page's writeback ends up during pagevec
696 * We moves tha page into tail of inactive.
697 */
Johannes Weiner925b7672012-01-12 17:18:15 -0800698 list_move_tail(&page->lru, &lruvec->lists[lru]);
Minchan Kim278df9f2011-03-22 16:32:54 -0700699 __count_vm_event(PGROTATED);
700 }
701
702 if (active)
703 __count_vm_event(PGDEACTIVATE);
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700704 update_page_reclaim_stat(lruvec, file, 0);
Minchan Kim31560182011-03-22 16:32:52 -0700705}
706
Minchan Kim31560182011-03-22 16:32:52 -0700707/*
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700708 * Drain pages out of the cpu's pagevecs.
709 * Either "cpu" is the current CPU, and preemption has already been
710 * disabled; or "cpu" is being hot-unplugged, and is already dead.
711 */
Konstantin Khlebnikovf0cb3c72012-03-21 16:34:06 -0700712void lru_add_drain_cpu(int cpu)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700713{
Mel Gorman13f7f782013-07-03 15:02:28 -0700714 struct pagevec *pvec = &per_cpu(lru_add_pvec, cpu);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700715
Mel Gorman13f7f782013-07-03 15:02:28 -0700716 if (pagevec_count(pvec))
Mel Gormana0b8cab32013-07-03 15:02:32 -0700717 __pagevec_lru_add(pvec);
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700718
719 pvec = &per_cpu(lru_rotate_pvecs, cpu);
720 if (pagevec_count(pvec)) {
721 unsigned long flags;
722
723 /* No harm done if a racing interrupt already did this */
724 local_irq_save(flags);
725 pagevec_move_tail(pvec);
726 local_irq_restore(flags);
727 }
Minchan Kim31560182011-03-22 16:32:52 -0700728
729 pvec = &per_cpu(lru_deactivate_pvecs, cpu);
730 if (pagevec_count(pvec))
Shaohua Li3dd7ae82011-03-22 16:33:45 -0700731 pagevec_lru_move_fn(pvec, lru_deactivate_fn, NULL);
Shaohua Lieb709b02011-05-24 17:12:55 -0700732
733 activate_page_drain(cpu);
Minchan Kim31560182011-03-22 16:32:52 -0700734}
735
736/**
737 * deactivate_page - forcefully deactivate a page
738 * @page: page to deactivate
739 *
740 * This function hints the VM that @page is a good reclaim candidate,
741 * for example if its invalidation fails due to the page being dirty
742 * or under writeback.
743 */
744void deactivate_page(struct page *page)
745{
Minchan Kim821ed6b2011-05-24 17:12:31 -0700746 /*
747 * In a workload with many unevictable page such as mprotect, unevictable
748 * page deactivation for accelerating reclaim is pointless.
749 */
750 if (PageUnevictable(page))
751 return;
752
Minchan Kim31560182011-03-22 16:32:52 -0700753 if (likely(get_page_unless_zero(page))) {
754 struct pagevec *pvec = &get_cpu_var(lru_deactivate_pvecs);
755
756 if (!pagevec_add(pvec, page))
Shaohua Li3dd7ae82011-03-22 16:33:45 -0700757 pagevec_lru_move_fn(pvec, lru_deactivate_fn, NULL);
Minchan Kim31560182011-03-22 16:32:52 -0700758 put_cpu_var(lru_deactivate_pvecs);
759 }
Andrew Morton80bfed92006-01-06 00:11:14 -0800760}
761
762void lru_add_drain(void)
763{
Konstantin Khlebnikovf0cb3c72012-03-21 16:34:06 -0700764 lru_add_drain_cpu(get_cpu());
Andrew Morton80bfed92006-01-06 00:11:14 -0800765 put_cpu();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700766}
767
David Howellsc4028952006-11-22 14:57:56 +0000768static void lru_add_drain_per_cpu(struct work_struct *dummy)
Nick Piggin053837f2006-01-18 17:42:27 -0800769{
770 lru_add_drain();
771}
772
Chris Metcalf5fbc4612013-09-12 15:13:55 -0700773static DEFINE_PER_CPU(struct work_struct, lru_add_drain_work);
774
775void lru_add_drain_all(void)
Nick Piggin053837f2006-01-18 17:42:27 -0800776{
Chris Metcalf5fbc4612013-09-12 15:13:55 -0700777 static DEFINE_MUTEX(lock);
778 static struct cpumask has_work;
779 int cpu;
780
781 mutex_lock(&lock);
782 get_online_cpus();
783 cpumask_clear(&has_work);
784
785 for_each_online_cpu(cpu) {
786 struct work_struct *work = &per_cpu(lru_add_drain_work, cpu);
787
788 if (pagevec_count(&per_cpu(lru_add_pvec, cpu)) ||
789 pagevec_count(&per_cpu(lru_rotate_pvecs, cpu)) ||
790 pagevec_count(&per_cpu(lru_deactivate_pvecs, cpu)) ||
791 need_activate_page_drain(cpu)) {
792 INIT_WORK(work, lru_add_drain_per_cpu);
793 schedule_work_on(cpu, work);
794 cpumask_set_cpu(cpu, &has_work);
795 }
796 }
797
798 for_each_cpu(cpu, &has_work)
799 flush_work(&per_cpu(lru_add_drain_work, cpu));
800
801 put_online_cpus();
802 mutex_unlock(&lock);
Nick Piggin053837f2006-01-18 17:42:27 -0800803}
804
Linus Torvalds1da177e2005-04-16 15:20:36 -0700805/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700806 * Batched page_cache_release(). Decrement the reference count on all the
807 * passed pages. If it fell to zero then remove the page from the LRU and
808 * free it.
809 *
810 * Avoid taking zone->lru_lock if possible, but if it is taken, retain it
811 * for the remainder of the operation.
812 *
Fernando Luis Vazquez Caoab33dc02008-07-29 22:33:40 -0700813 * The locking in this function is against shrink_inactive_list(): we recheck
814 * the page count inside the lock to see whether shrink_inactive_list()
815 * grabbed the page via the LRU. If it did, give up: shrink_inactive_list()
816 * will free it.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700817 */
818void release_pages(struct page **pages, int nr, int cold)
819{
820 int i;
Konstantin Khlebnikovcc598502012-01-10 15:07:04 -0800821 LIST_HEAD(pages_to_free);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700822 struct zone *zone = NULL;
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700823 struct lruvec *lruvec;
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700824 unsigned long uninitialized_var(flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700825
Linus Torvalds1da177e2005-04-16 15:20:36 -0700826 for (i = 0; i < nr; i++) {
827 struct page *page = pages[i];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700828
Nick Piggin8519fb32006-02-07 12:58:52 -0800829 if (unlikely(PageCompound(page))) {
830 if (zone) {
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700831 spin_unlock_irqrestore(&zone->lru_lock, flags);
Nick Piggin8519fb32006-02-07 12:58:52 -0800832 zone = NULL;
833 }
834 put_compound_page(page);
835 continue;
836 }
837
Nick Pigginb5810032005-10-29 18:16:12 -0700838 if (!put_page_testzero(page))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700839 continue;
840
Nick Piggin46453a62006-03-22 00:07:58 -0800841 if (PageLRU(page)) {
842 struct zone *pagezone = page_zone(page);
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700843
Nick Piggin46453a62006-03-22 00:07:58 -0800844 if (pagezone != zone) {
845 if (zone)
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700846 spin_unlock_irqrestore(&zone->lru_lock,
847 flags);
Nick Piggin46453a62006-03-22 00:07:58 -0800848 zone = pagezone;
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700849 spin_lock_irqsave(&zone->lru_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700850 }
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700851
852 lruvec = mem_cgroup_page_lruvec(page, zone);
Nick Piggin725d7042006-09-25 23:30:55 -0700853 VM_BUG_ON(!PageLRU(page));
Nick Piggin67453912006-03-22 00:08:00 -0800854 __ClearPageLRU(page);
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700855 del_page_from_lru_list(page, lruvec, page_off_lru(page));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700856 }
Nick Piggin46453a62006-03-22 00:07:58 -0800857
Mel Gormanc53954a2013-07-03 15:02:34 -0700858 /* Clear Active bit in case of parallel mark_page_accessed */
859 ClearPageActive(page);
860
Konstantin Khlebnikovcc598502012-01-10 15:07:04 -0800861 list_add(&page->lru, &pages_to_free);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700862 }
863 if (zone)
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700864 spin_unlock_irqrestore(&zone->lru_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700865
Konstantin Khlebnikovcc598502012-01-10 15:07:04 -0800866 free_hot_cold_page_list(&pages_to_free, cold);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700867}
Miklos Szeredi0be85572010-10-27 15:34:46 -0700868EXPORT_SYMBOL(release_pages);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700869
870/*
871 * The pages which we're about to release may be in the deferred lru-addition
872 * queues. That would prevent them from really being freed right now. That's
873 * OK from a correctness point of view but is inefficient - those pages may be
874 * cache-warm and we want to give them back to the page allocator ASAP.
875 *
876 * So __pagevec_release() will drain those queues here. __pagevec_lru_add()
877 * and __pagevec_lru_add_active() call release_pages() directly to avoid
878 * mutual recursion.
879 */
880void __pagevec_release(struct pagevec *pvec)
881{
882 lru_add_drain();
883 release_pages(pvec->pages, pagevec_count(pvec), pvec->cold);
884 pagevec_reinit(pvec);
885}
Steve French7f285702005-11-01 10:22:55 -0800886EXPORT_SYMBOL(__pagevec_release);
887
Hugh Dickins12d27102012-01-12 17:19:52 -0800888#ifdef CONFIG_TRANSPARENT_HUGEPAGE
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800889/* used by __split_huge_page_refcount() */
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700890void lru_add_page_tail(struct page *page, struct page *page_tail,
Shaohua Li5bc7b8a2013-04-29 15:08:36 -0700891 struct lruvec *lruvec, struct list_head *list)
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800892{
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800893 const int file = 0;
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800894
895 VM_BUG_ON(!PageHead(page));
896 VM_BUG_ON(PageCompound(page_tail));
897 VM_BUG_ON(PageLRU(page_tail));
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700898 VM_BUG_ON(NR_CPUS != 1 &&
899 !spin_is_locked(&lruvec_zone(lruvec)->lru_lock));
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800900
Shaohua Li5bc7b8a2013-04-29 15:08:36 -0700901 if (!list)
902 SetPageLRU(page_tail);
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800903
Hugh Dickins12d27102012-01-12 17:19:52 -0800904 if (likely(PageLRU(page)))
905 list_add_tail(&page_tail->lru, &page->lru);
Shaohua Li5bc7b8a2013-04-29 15:08:36 -0700906 else if (list) {
907 /* page reclaim is reclaiming a huge page */
908 get_page(page_tail);
909 list_add_tail(&page_tail->lru, list);
910 } else {
Hugh Dickins12d27102012-01-12 17:19:52 -0800911 struct list_head *list_head;
912 /*
913 * Head page has not yet been counted, as an hpage,
914 * so we must account for each subpage individually.
915 *
916 * Use the standard add function to put page_tail on the list,
917 * but then correct its position so they all end up in order.
918 */
Kirill A. Shutemove180cf82013-07-31 13:53:39 -0700919 add_page_to_lru_list(page_tail, lruvec, page_lru(page_tail));
Hugh Dickins12d27102012-01-12 17:19:52 -0800920 list_head = page_tail->lru.prev;
921 list_move_tail(&page_tail->lru, list_head);
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800922 }
Hugh Dickins75121022012-03-05 14:59:18 -0800923
924 if (!PageUnevictable(page))
Kirill A. Shutemove180cf82013-07-31 13:53:39 -0700925 update_page_reclaim_stat(lruvec, file, PageActive(page_tail));
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800926}
Hugh Dickins12d27102012-01-12 17:19:52 -0800927#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800928
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700929static void __pagevec_lru_add_fn(struct page *page, struct lruvec *lruvec,
930 void *arg)
Shaohua Li3dd7ae82011-03-22 16:33:45 -0700931{
Mel Gorman13f7f782013-07-03 15:02:28 -0700932 int file = page_is_file_cache(page);
933 int active = PageActive(page);
934 enum lru_list lru = page_lru(page);
Shaohua Li3dd7ae82011-03-22 16:33:45 -0700935
Shaohua Li3dd7ae82011-03-22 16:33:45 -0700936 VM_BUG_ON(PageLRU(page));
937
938 SetPageLRU(page);
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700939 add_page_to_lru_list(page, lruvec, lru);
940 update_page_reclaim_stat(lruvec, file, active);
Mel Gormanc6286c92013-07-03 15:02:26 -0700941 trace_mm_lru_insertion(page, page_to_pfn(page), lru, trace_pagemap_flags(page));
Shaohua Li3dd7ae82011-03-22 16:33:45 -0700942}
943
Linus Torvalds1da177e2005-04-16 15:20:36 -0700944/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700945 * Add the passed pages to the LRU, then drop the caller's refcount
946 * on them. Reinitialises the caller's pagevec.
947 */
Mel Gormana0b8cab32013-07-03 15:02:32 -0700948void __pagevec_lru_add(struct pagevec *pvec)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700949{
Mel Gormana0b8cab32013-07-03 15:02:32 -0700950 pagevec_lru_move_fn(pvec, __pagevec_lru_add_fn, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700951}
Hugh Dickins5095ae832012-01-12 17:19:58 -0800952EXPORT_SYMBOL(__pagevec_lru_add);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700953
Linus Torvalds1da177e2005-04-16 15:20:36 -0700954/**
955 * pagevec_lookup - gang pagecache lookup
956 * @pvec: Where the resulting pages are placed
957 * @mapping: The address_space to search
958 * @start: The starting page index
959 * @nr_pages: The maximum number of pages
960 *
961 * pagevec_lookup() will search for and return a group of up to @nr_pages pages
962 * in the mapping. The pages are placed in @pvec. pagevec_lookup() takes a
963 * reference against the pages in @pvec.
964 *
965 * The search returns a group of mapping-contiguous pages with ascending
966 * indexes. There may be holes in the indices due to not-present pages.
967 *
968 * pagevec_lookup() returns the number of pages which were found.
969 */
970unsigned pagevec_lookup(struct pagevec *pvec, struct address_space *mapping,
971 pgoff_t start, unsigned nr_pages)
972{
973 pvec->nr = find_get_pages(mapping, start, nr_pages, pvec->pages);
974 return pagevec_count(pvec);
975}
Christoph Hellwig78539fd2006-01-11 20:47:41 +1100976EXPORT_SYMBOL(pagevec_lookup);
977
Linus Torvalds1da177e2005-04-16 15:20:36 -0700978unsigned pagevec_lookup_tag(struct pagevec *pvec, struct address_space *mapping,
979 pgoff_t *index, int tag, unsigned nr_pages)
980{
981 pvec->nr = find_get_pages_tag(mapping, index, tag,
982 nr_pages, pvec->pages);
983 return pagevec_count(pvec);
984}
Steve French7f285702005-11-01 10:22:55 -0800985EXPORT_SYMBOL(pagevec_lookup_tag);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700986
Linus Torvalds1da177e2005-04-16 15:20:36 -0700987/*
988 * Perform any setup for the swap system
989 */
990void __init swap_setup(void)
991{
Jan Beulich44813742009-09-21 17:03:05 -0700992 unsigned long megs = totalram_pages >> (20 - PAGE_SHIFT);
Peter Zijlstrae0bf68d2007-10-16 23:25:46 -0700993#ifdef CONFIG_SWAP
Shaohua Li33806f02013-02-22 16:34:37 -0800994 int i;
995
Mikulas Patocka8077c0d2013-10-14 12:14:13 -0400996 if (bdi_init(swapper_spaces[0].backing_dev_info))
997 panic("Failed to init swap bdi");
Shaohua Li33806f02013-02-22 16:34:37 -0800998 for (i = 0; i < MAX_SWAPFILES; i++) {
999 spin_lock_init(&swapper_spaces[i].tree_lock);
1000 INIT_LIST_HEAD(&swapper_spaces[i].i_mmap_nonlinear);
1001 }
Peter Zijlstrae0bf68d2007-10-16 23:25:46 -07001002#endif
1003
Linus Torvalds1da177e2005-04-16 15:20:36 -07001004 /* Use a smaller cluster for small-memory machines */
1005 if (megs < 16)
1006 page_cluster = 2;
1007 else
1008 page_cluster = 3;
1009 /*
1010 * Right now other parts of the system means that we
1011 * _really_ don't want to cluster much more
1012 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001013}