4 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
8 * This file contains the default values for the operation of the
9 * Linux VM subsystem. Fine-tuning documentation can be found in
10 * Documentation/sysctl/vm.txt.
12 * Swap aging added 23.2.95, Stephen Tweedie.
13 * Buffermem limits added 12.3.98, Rik van Riel.
17 #include <linux/sched.h>
18 #include <linux/kernel_stat.h>
19 #include <linux/swap.h>
20 #include <linux/mman.h>
21 #include <linux/pagemap.h>
22 #include <linux/pagevec.h>
23 #include <linux/init.h>
24 #include <linux/export.h>
25 #include <linux/mm_inline.h>
26 #include <linux/percpu_counter.h>
27 #include <linux/memremap.h>
28 #include <linux/percpu.h>
29 #include <linux/cpu.h>
30 #include <linux/notifier.h>
31 #include <linux/backing-dev.h>
32 #include <linux/memcontrol.h>
33 #include <linux/gfp.h>
34 #include <linux/uio.h>
35 #include <linux/hugetlb.h>
36 #include <linux/page_idle.h>
40 #define CREATE_TRACE_POINTS
41 #include <trace/events/pagemap.h>
43 /* How many pages do we try to swap or page in/out together? */
46 static DEFINE_PER_CPU(struct pagevec
, lru_add_pvec
);
47 static DEFINE_PER_CPU(struct pagevec
, lru_rotate_pvecs
);
48 static DEFINE_PER_CPU(struct pagevec
, lru_deactivate_file_pvecs
);
49 static DEFINE_PER_CPU(struct pagevec
, lru_lazyfree_pvecs
);
51 static DEFINE_PER_CPU(struct pagevec
, activate_page_pvecs
);
55 * This path almost never happens for VM activity - pages are normally
56 * freed via pagevecs. But it gets used by networking.
58 static void __page_cache_release(struct page
*page
)
61 struct zone
*zone
= page_zone(page
);
62 struct lruvec
*lruvec
;
65 spin_lock_irqsave(zone_lru_lock(zone
), flags
);
66 lruvec
= mem_cgroup_page_lruvec(page
, zone
->zone_pgdat
);
67 VM_BUG_ON_PAGE(!PageLRU(page
), page
);
69 del_page_from_lru_list(page
, lruvec
, page_off_lru(page
));
70 spin_unlock_irqrestore(zone_lru_lock(zone
), flags
);
72 __ClearPageWaiters(page
);
73 mem_cgroup_uncharge(page
);
76 static void __put_single_page(struct page
*page
)
78 __page_cache_release(page
);
79 free_unref_page(page
);
82 static void __put_compound_page(struct page
*page
)
84 compound_page_dtor
*dtor
;
87 * __page_cache_release() is supposed to be called for thp, not for
88 * hugetlb. This is because hugetlb page does never have PageLRU set
89 * (it's never listed to any LRU lists) and no memcg routines should
90 * be called for hugetlb (it has a separate hugetlb_cgroup.)
93 __page_cache_release(page
);
94 dtor
= get_compound_page_dtor(page
);
98 void __put_page(struct page
*page
)
100 if (is_zone_device_page(page
)) {
101 put_dev_pagemap(page
->pgmap
);
104 * The page belongs to the device that created pgmap. Do
105 * not return it to page allocator.
110 if (unlikely(PageCompound(page
)))
111 __put_compound_page(page
);
113 __put_single_page(page
);
115 EXPORT_SYMBOL(__put_page
);
118 * put_pages_list() - release a list of pages
119 * @pages: list of pages threaded on page->lru
121 * Release a list of pages which are strung together on page.lru. Currently
122 * used by read_cache_pages() and related error recovery code.
124 void put_pages_list(struct list_head
*pages
)
126 while (!list_empty(pages
)) {
129 victim
= list_entry(pages
->prev
, struct page
, lru
);
130 list_del(&victim
->lru
);
134 EXPORT_SYMBOL(put_pages_list
);
137 * get_kernel_pages() - pin kernel pages in memory
138 * @kiov: An array of struct kvec structures
139 * @nr_segs: number of segments to pin
140 * @write: pinning for read/write, currently ignored
141 * @pages: array that receives pointers to the pages pinned.
142 * Should be at least nr_segs long.
144 * Returns number of pages pinned. This may be fewer than the number
145 * requested. If nr_pages is 0 or negative, returns 0. If no pages
146 * were pinned, returns -errno. Each page returned must be released
147 * with a put_page() call when it is finished with.
149 int get_kernel_pages(const struct kvec
*kiov
, int nr_segs
, int write
,
154 for (seg
= 0; seg
< nr_segs
; seg
++) {
155 if (WARN_ON(kiov
[seg
].iov_len
!= PAGE_SIZE
))
158 pages
[seg
] = kmap_to_page(kiov
[seg
].iov_base
);
159 get_page(pages
[seg
]);
164 EXPORT_SYMBOL_GPL(get_kernel_pages
);
167 * get_kernel_page() - pin a kernel page in memory
168 * @start: starting kernel address
169 * @write: pinning for read/write, currently ignored
170 * @pages: array that receives pointer to the page pinned.
171 * Must be at least nr_segs long.
173 * Returns 1 if page is pinned. If the page was not pinned, returns
174 * -errno. The page returned must be released with a put_page() call
175 * when it is finished with.
177 int get_kernel_page(unsigned long start
, int write
, struct page
**pages
)
179 const struct kvec kiov
= {
180 .iov_base
= (void *)start
,
184 return get_kernel_pages(&kiov
, 1, write
, pages
);
186 EXPORT_SYMBOL_GPL(get_kernel_page
);
188 static void pagevec_lru_move_fn(struct pagevec
*pvec
,
189 void (*move_fn
)(struct page
*page
, struct lruvec
*lruvec
, void *arg
),
193 struct pglist_data
*pgdat
= NULL
;
194 struct lruvec
*lruvec
;
195 unsigned long flags
= 0;
197 for (i
= 0; i
< pagevec_count(pvec
); i
++) {
198 struct page
*page
= pvec
->pages
[i
];
199 struct pglist_data
*pagepgdat
= page_pgdat(page
);
201 if (pagepgdat
!= pgdat
) {
203 spin_unlock_irqrestore(&pgdat
->lru_lock
, flags
);
205 spin_lock_irqsave(&pgdat
->lru_lock
, flags
);
208 lruvec
= mem_cgroup_page_lruvec(page
, pgdat
);
209 (*move_fn
)(page
, lruvec
, arg
);
212 spin_unlock_irqrestore(&pgdat
->lru_lock
, flags
);
213 release_pages(pvec
->pages
, pvec
->nr
);
214 pagevec_reinit(pvec
);
217 static void pagevec_move_tail_fn(struct page
*page
, struct lruvec
*lruvec
,
222 if (PageLRU(page
) && !PageUnevictable(page
)) {
223 del_page_from_lru_list(page
, lruvec
, page_lru(page
));
224 ClearPageActive(page
);
225 add_page_to_lru_list_tail(page
, lruvec
, page_lru(page
));
231 * pagevec_move_tail() must be called with IRQ disabled.
232 * Otherwise this may cause nasty races.
234 static void pagevec_move_tail(struct pagevec
*pvec
)
238 pagevec_lru_move_fn(pvec
, pagevec_move_tail_fn
, &pgmoved
);
239 __count_vm_events(PGROTATED
, pgmoved
);
243 * Writeback is about to end against a page which has been marked for immediate
244 * reclaim. If it still appears to be reclaimable, move it to the tail of the
247 void rotate_reclaimable_page(struct page
*page
)
249 if (!PageLocked(page
) && !PageDirty(page
) &&
250 !PageUnevictable(page
) && PageLRU(page
)) {
251 struct pagevec
*pvec
;
255 local_irq_save(flags
);
256 pvec
= this_cpu_ptr(&lru_rotate_pvecs
);
257 if (!pagevec_add(pvec
, page
) || PageCompound(page
))
258 pagevec_move_tail(pvec
);
259 local_irq_restore(flags
);
263 static void update_page_reclaim_stat(struct lruvec
*lruvec
,
264 int file
, int rotated
)
266 struct zone_reclaim_stat
*reclaim_stat
= &lruvec
->reclaim_stat
;
268 reclaim_stat
->recent_scanned
[file
]++;
270 reclaim_stat
->recent_rotated
[file
]++;
273 static void __activate_page(struct page
*page
, struct lruvec
*lruvec
,
276 if (PageLRU(page
) && !PageActive(page
) && !PageUnevictable(page
)) {
277 int file
= page_is_file_cache(page
);
278 int lru
= page_lru_base_type(page
);
280 del_page_from_lru_list(page
, lruvec
, lru
);
283 add_page_to_lru_list(page
, lruvec
, lru
);
284 trace_mm_lru_activate(page
);
286 __count_vm_event(PGACTIVATE
);
287 update_page_reclaim_stat(lruvec
, file
, 1);
292 static void activate_page_drain(int cpu
)
294 struct pagevec
*pvec
= &per_cpu(activate_page_pvecs
, cpu
);
296 if (pagevec_count(pvec
))
297 pagevec_lru_move_fn(pvec
, __activate_page
, NULL
);
300 static bool need_activate_page_drain(int cpu
)
302 return pagevec_count(&per_cpu(activate_page_pvecs
, cpu
)) != 0;
305 void activate_page(struct page
*page
)
307 page
= compound_head(page
);
308 if (PageLRU(page
) && !PageActive(page
) && !PageUnevictable(page
)) {
309 struct pagevec
*pvec
= &get_cpu_var(activate_page_pvecs
);
312 if (!pagevec_add(pvec
, page
) || PageCompound(page
))
313 pagevec_lru_move_fn(pvec
, __activate_page
, NULL
);
314 put_cpu_var(activate_page_pvecs
);
319 static inline void activate_page_drain(int cpu
)
323 void activate_page(struct page
*page
)
325 struct zone
*zone
= page_zone(page
);
327 page
= compound_head(page
);
328 spin_lock_irq(zone_lru_lock(zone
));
329 __activate_page(page
, mem_cgroup_page_lruvec(page
, zone
->zone_pgdat
), NULL
);
330 spin_unlock_irq(zone_lru_lock(zone
));
334 static void __lru_cache_activate_page(struct page
*page
)
336 struct pagevec
*pvec
= &get_cpu_var(lru_add_pvec
);
340 * Search backwards on the optimistic assumption that the page being
341 * activated has just been added to this pagevec. Note that only
342 * the local pagevec is examined as a !PageLRU page could be in the
343 * process of being released, reclaimed, migrated or on a remote
344 * pagevec that is currently being drained. Furthermore, marking
345 * a remote pagevec's page PageActive potentially hits a race where
346 * a page is marked PageActive just after it is added to the inactive
347 * list causing accounting errors and BUG_ON checks to trigger.
349 for (i
= pagevec_count(pvec
) - 1; i
>= 0; i
--) {
350 struct page
*pagevec_page
= pvec
->pages
[i
];
352 if (pagevec_page
== page
) {
358 put_cpu_var(lru_add_pvec
);
362 * Mark a page as having seen activity.
364 * inactive,unreferenced -> inactive,referenced
365 * inactive,referenced -> active,unreferenced
366 * active,unreferenced -> active,referenced
368 * When a newly allocated page is not yet visible, so safe for non-atomic ops,
369 * __SetPageReferenced(page) may be substituted for mark_page_accessed(page).
371 void mark_page_accessed(struct page
*page
)
373 page
= compound_head(page
);
374 if (!PageActive(page
) && !PageUnevictable(page
) &&
375 PageReferenced(page
)) {
378 * If the page is on the LRU, queue it for activation via
379 * activate_page_pvecs. Otherwise, assume the page is on a
380 * pagevec, mark it active and it'll be moved to the active
381 * LRU on the next drain.
386 __lru_cache_activate_page(page
);
387 ClearPageReferenced(page
);
388 if (page_is_file_cache(page
))
389 workingset_activation(page
);
390 } else if (!PageReferenced(page
)) {
391 SetPageReferenced(page
);
393 if (page_is_idle(page
))
394 clear_page_idle(page
);
396 EXPORT_SYMBOL(mark_page_accessed
);
398 static void __lru_cache_add(struct page
*page
)
400 struct pagevec
*pvec
= &get_cpu_var(lru_add_pvec
);
403 if (!pagevec_add(pvec
, page
) || PageCompound(page
))
404 __pagevec_lru_add(pvec
);
405 put_cpu_var(lru_add_pvec
);
409 * lru_cache_add: add a page to the page lists
410 * @page: the page to add
412 void lru_cache_add_anon(struct page
*page
)
414 if (PageActive(page
))
415 ClearPageActive(page
);
416 __lru_cache_add(page
);
419 void lru_cache_add_file(struct page
*page
)
421 if (PageActive(page
))
422 ClearPageActive(page
);
423 __lru_cache_add(page
);
425 EXPORT_SYMBOL(lru_cache_add_file
);
428 * lru_cache_add - add a page to a page list
429 * @page: the page to be added to the LRU.
431 * Queue the page for addition to the LRU via pagevec. The decision on whether
432 * to add the page to the [in]active [file|anon] list is deferred until the
433 * pagevec is drained. This gives a chance for the caller of lru_cache_add()
434 * have the page added to the active list using mark_page_accessed().
436 void lru_cache_add(struct page
*page
)
438 VM_BUG_ON_PAGE(PageActive(page
) && PageUnevictable(page
), page
);
439 VM_BUG_ON_PAGE(PageLRU(page
), page
);
440 __lru_cache_add(page
);
444 * add_page_to_unevictable_list - add a page to the unevictable list
445 * @page: the page to be added to the unevictable list
447 * Add page directly to its zone's unevictable list. To avoid races with
448 * tasks that might be making the page evictable, through eg. munlock,
449 * munmap or exit, while it's not on the lru, we want to add the page
450 * while it's locked or otherwise "invisible" to other tasks. This is
451 * difficult to do when using the pagevec cache, so bypass that.
453 void add_page_to_unevictable_list(struct page
*page
)
455 struct pglist_data
*pgdat
= page_pgdat(page
);
456 struct lruvec
*lruvec
;
458 spin_lock_irq(&pgdat
->lru_lock
);
459 lruvec
= mem_cgroup_page_lruvec(page
, pgdat
);
460 ClearPageActive(page
);
461 SetPageUnevictable(page
);
463 add_page_to_lru_list(page
, lruvec
, LRU_UNEVICTABLE
);
464 spin_unlock_irq(&pgdat
->lru_lock
);
468 * lru_cache_add_active_or_unevictable
469 * @page: the page to be added to LRU
470 * @vma: vma in which page is mapped for determining reclaimability
472 * Place @page on the active or unevictable LRU list, depending on its
473 * evictability. Note that if the page is not evictable, it goes
474 * directly back onto it's zone's unevictable list, it does NOT use a
477 void lru_cache_add_active_or_unevictable(struct page
*page
,
478 struct vm_area_struct
*vma
)
480 VM_BUG_ON_PAGE(PageLRU(page
), page
);
482 if (likely((vma
->vm_flags
& (VM_LOCKED
| VM_SPECIAL
)) != VM_LOCKED
)) {
488 if (!TestSetPageMlocked(page
)) {
490 * We use the irq-unsafe __mod_zone_page_stat because this
491 * counter is not modified from interrupt context, and the pte
492 * lock is held(spinlock), which implies preemption disabled.
494 __mod_zone_page_state(page_zone(page
), NR_MLOCK
,
495 hpage_nr_pages(page
));
496 count_vm_event(UNEVICTABLE_PGMLOCKED
);
498 add_page_to_unevictable_list(page
);
502 * If the page can not be invalidated, it is moved to the
503 * inactive list to speed up its reclaim. It is moved to the
504 * head of the list, rather than the tail, to give the flusher
505 * threads some time to write it out, as this is much more
506 * effective than the single-page writeout from reclaim.
508 * If the page isn't page_mapped and dirty/writeback, the page
509 * could reclaim asap using PG_reclaim.
511 * 1. active, mapped page -> none
512 * 2. active, dirty/writeback page -> inactive, head, PG_reclaim
513 * 3. inactive, mapped page -> none
514 * 4. inactive, dirty/writeback page -> inactive, head, PG_reclaim
515 * 5. inactive, clean -> inactive, tail
518 * In 4, why it moves inactive's head, the VM expects the page would
519 * be write it out by flusher threads as this is much more effective
520 * than the single-page writeout from reclaim.
522 static void lru_deactivate_file_fn(struct page
*page
, struct lruvec
*lruvec
,
531 if (PageUnevictable(page
))
534 /* Some processes are using the page */
535 if (page_mapped(page
))
538 active
= PageActive(page
);
539 file
= page_is_file_cache(page
);
540 lru
= page_lru_base_type(page
);
542 del_page_from_lru_list(page
, lruvec
, lru
+ active
);
543 ClearPageActive(page
);
544 ClearPageReferenced(page
);
545 add_page_to_lru_list(page
, lruvec
, lru
);
547 if (PageWriteback(page
) || PageDirty(page
)) {
549 * PG_reclaim could be raced with end_page_writeback
550 * It can make readahead confusing. But race window
551 * is _really_ small and it's non-critical problem.
553 SetPageReclaim(page
);
556 * The page's writeback ends up during pagevec
557 * We moves tha page into tail of inactive.
559 list_move_tail(&page
->lru
, &lruvec
->lists
[lru
]);
560 __count_vm_event(PGROTATED
);
564 __count_vm_event(PGDEACTIVATE
);
565 update_page_reclaim_stat(lruvec
, file
, 0);
569 static void lru_lazyfree_fn(struct page
*page
, struct lruvec
*lruvec
,
572 if (PageLRU(page
) && PageAnon(page
) && PageSwapBacked(page
) &&
573 !PageSwapCache(page
) && !PageUnevictable(page
)) {
574 bool active
= PageActive(page
);
576 del_page_from_lru_list(page
, lruvec
,
577 LRU_INACTIVE_ANON
+ active
);
578 ClearPageActive(page
);
579 ClearPageReferenced(page
);
581 * lazyfree pages are clean anonymous pages. They have
582 * SwapBacked flag cleared to distinguish normal anonymous
585 ClearPageSwapBacked(page
);
586 add_page_to_lru_list(page
, lruvec
, LRU_INACTIVE_FILE
);
588 __count_vm_events(PGLAZYFREE
, hpage_nr_pages(page
));
589 count_memcg_page_event(page
, PGLAZYFREE
);
590 update_page_reclaim_stat(lruvec
, 1, 0);
595 * Drain pages out of the cpu's pagevecs.
596 * Either "cpu" is the current CPU, and preemption has already been
597 * disabled; or "cpu" is being hot-unplugged, and is already dead.
599 void lru_add_drain_cpu(int cpu
)
601 struct pagevec
*pvec
= &per_cpu(lru_add_pvec
, cpu
);
603 if (pagevec_count(pvec
))
604 __pagevec_lru_add(pvec
);
606 pvec
= &per_cpu(lru_rotate_pvecs
, cpu
);
607 if (pagevec_count(pvec
)) {
610 /* No harm done if a racing interrupt already did this */
611 local_irq_save(flags
);
612 pagevec_move_tail(pvec
);
613 local_irq_restore(flags
);
616 pvec
= &per_cpu(lru_deactivate_file_pvecs
, cpu
);
617 if (pagevec_count(pvec
))
618 pagevec_lru_move_fn(pvec
, lru_deactivate_file_fn
, NULL
);
620 pvec
= &per_cpu(lru_lazyfree_pvecs
, cpu
);
621 if (pagevec_count(pvec
))
622 pagevec_lru_move_fn(pvec
, lru_lazyfree_fn
, NULL
);
624 activate_page_drain(cpu
);
628 * deactivate_file_page - forcefully deactivate a file page
629 * @page: page to deactivate
631 * This function hints the VM that @page is a good reclaim candidate,
632 * for example if its invalidation fails due to the page being dirty
633 * or under writeback.
635 void deactivate_file_page(struct page
*page
)
638 * In a workload with many unevictable page such as mprotect,
639 * unevictable page deactivation for accelerating reclaim is pointless.
641 if (PageUnevictable(page
))
644 if (likely(get_page_unless_zero(page
))) {
645 struct pagevec
*pvec
= &get_cpu_var(lru_deactivate_file_pvecs
);
647 if (!pagevec_add(pvec
, page
) || PageCompound(page
))
648 pagevec_lru_move_fn(pvec
, lru_deactivate_file_fn
, NULL
);
649 put_cpu_var(lru_deactivate_file_pvecs
);
654 * mark_page_lazyfree - make an anon page lazyfree
655 * @page: page to deactivate
657 * mark_page_lazyfree() moves @page to the inactive file list.
658 * This is done to accelerate the reclaim of @page.
660 void mark_page_lazyfree(struct page
*page
)
662 if (PageLRU(page
) && PageAnon(page
) && PageSwapBacked(page
) &&
663 !PageSwapCache(page
) && !PageUnevictable(page
)) {
664 struct pagevec
*pvec
= &get_cpu_var(lru_lazyfree_pvecs
);
667 if (!pagevec_add(pvec
, page
) || PageCompound(page
))
668 pagevec_lru_move_fn(pvec
, lru_lazyfree_fn
, NULL
);
669 put_cpu_var(lru_lazyfree_pvecs
);
673 void lru_add_drain(void)
675 lru_add_drain_cpu(get_cpu());
681 static DEFINE_PER_CPU(struct work_struct
, lru_add_drain_work
);
683 static void lru_add_drain_per_cpu(struct work_struct
*dummy
)
688 void lru_add_drain_all(void)
694 void lru_add_drain_all_cpuslocked(void)
696 static DEFINE_MUTEX(lock
);
697 static struct cpumask has_work
;
701 * Make sure nobody triggers this path before mm_percpu_wq is fully
704 if (WARN_ON(!mm_percpu_wq
))
708 cpumask_clear(&has_work
);
710 for_each_online_cpu(cpu
) {
711 struct work_struct
*work
= &per_cpu(lru_add_drain_work
, cpu
);
713 if (pagevec_count(&per_cpu(lru_add_pvec
, cpu
)) ||
714 pagevec_count(&per_cpu(lru_rotate_pvecs
, cpu
)) ||
715 pagevec_count(&per_cpu(lru_deactivate_file_pvecs
, cpu
)) ||
716 pagevec_count(&per_cpu(lru_lazyfree_pvecs
, cpu
)) ||
717 need_activate_page_drain(cpu
)) {
718 INIT_WORK(work
, lru_add_drain_per_cpu
);
719 queue_work_on(cpu
, mm_percpu_wq
, work
);
720 cpumask_set_cpu(cpu
, &has_work
);
724 for_each_cpu(cpu
, &has_work
)
725 flush_work(&per_cpu(lru_add_drain_work
, cpu
));
730 void lru_add_drain_all(void)
733 lru_add_drain_all_cpuslocked();
738 * release_pages - batched put_page()
739 * @pages: array of pages to release
740 * @nr: number of pages
741 * @cold: whether the pages are cache cold
743 * Decrement the reference count on all the pages in @pages. If it
744 * fell to zero, remove the page from the LRU and free it.
746 void release_pages(struct page
**pages
, int nr
)
749 LIST_HEAD(pages_to_free
);
750 struct pglist_data
*locked_pgdat
= NULL
;
751 struct lruvec
*lruvec
;
752 unsigned long uninitialized_var(flags
);
753 unsigned int uninitialized_var(lock_batch
);
755 for (i
= 0; i
< nr
; i
++) {
756 struct page
*page
= pages
[i
];
759 * Make sure the IRQ-safe lock-holding time does not get
760 * excessive with a continuous string of pages from the
761 * same pgdat. The lock is held only if pgdat != NULL.
763 if (locked_pgdat
&& ++lock_batch
== SWAP_CLUSTER_MAX
) {
764 spin_unlock_irqrestore(&locked_pgdat
->lru_lock
, flags
);
768 if (is_huge_zero_page(page
))
771 /* Device public page can not be huge page */
772 if (is_device_public_page(page
)) {
774 spin_unlock_irqrestore(&locked_pgdat
->lru_lock
,
778 put_zone_device_private_or_public_page(page
);
782 page
= compound_head(page
);
783 if (!put_page_testzero(page
))
786 if (PageCompound(page
)) {
788 spin_unlock_irqrestore(&locked_pgdat
->lru_lock
, flags
);
791 __put_compound_page(page
);
796 struct pglist_data
*pgdat
= page_pgdat(page
);
798 if (pgdat
!= locked_pgdat
) {
800 spin_unlock_irqrestore(&locked_pgdat
->lru_lock
,
803 locked_pgdat
= pgdat
;
804 spin_lock_irqsave(&locked_pgdat
->lru_lock
, flags
);
807 lruvec
= mem_cgroup_page_lruvec(page
, locked_pgdat
);
808 VM_BUG_ON_PAGE(!PageLRU(page
), page
);
809 __ClearPageLRU(page
);
810 del_page_from_lru_list(page
, lruvec
, page_off_lru(page
));
813 /* Clear Active bit in case of parallel mark_page_accessed */
814 __ClearPageActive(page
);
815 __ClearPageWaiters(page
);
817 list_add(&page
->lru
, &pages_to_free
);
820 spin_unlock_irqrestore(&locked_pgdat
->lru_lock
, flags
);
822 mem_cgroup_uncharge_list(&pages_to_free
);
823 free_unref_page_list(&pages_to_free
);
825 EXPORT_SYMBOL(release_pages
);
828 * The pages which we're about to release may be in the deferred lru-addition
829 * queues. That would prevent them from really being freed right now. That's
830 * OK from a correctness point of view but is inefficient - those pages may be
831 * cache-warm and we want to give them back to the page allocator ASAP.
833 * So __pagevec_release() will drain those queues here. __pagevec_lru_add()
834 * and __pagevec_lru_add_active() call release_pages() directly to avoid
837 void __pagevec_release(struct pagevec
*pvec
)
839 if (!pvec
->percpu_pvec_drained
) {
841 pvec
->percpu_pvec_drained
= true;
843 release_pages(pvec
->pages
, pagevec_count(pvec
));
844 pagevec_reinit(pvec
);
846 EXPORT_SYMBOL(__pagevec_release
);
848 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
849 /* used by __split_huge_page_refcount() */
850 void lru_add_page_tail(struct page
*page
, struct page
*page_tail
,
851 struct lruvec
*lruvec
, struct list_head
*list
)
855 VM_BUG_ON_PAGE(!PageHead(page
), page
);
856 VM_BUG_ON_PAGE(PageCompound(page_tail
), page
);
857 VM_BUG_ON_PAGE(PageLRU(page_tail
), page
);
858 VM_BUG_ON(NR_CPUS
!= 1 &&
859 !spin_is_locked(&lruvec_pgdat(lruvec
)->lru_lock
));
862 SetPageLRU(page_tail
);
864 if (likely(PageLRU(page
)))
865 list_add_tail(&page_tail
->lru
, &page
->lru
);
867 /* page reclaim is reclaiming a huge page */
869 list_add_tail(&page_tail
->lru
, list
);
871 struct list_head
*list_head
;
873 * Head page has not yet been counted, as an hpage,
874 * so we must account for each subpage individually.
876 * Use the standard add function to put page_tail on the list,
877 * but then correct its position so they all end up in order.
879 add_page_to_lru_list(page_tail
, lruvec
, page_lru(page_tail
));
880 list_head
= page_tail
->lru
.prev
;
881 list_move_tail(&page_tail
->lru
, list_head
);
884 if (!PageUnevictable(page
))
885 update_page_reclaim_stat(lruvec
, file
, PageActive(page_tail
));
887 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
889 static void __pagevec_lru_add_fn(struct page
*page
, struct lruvec
*lruvec
,
892 int file
= page_is_file_cache(page
);
893 int active
= PageActive(page
);
894 enum lru_list lru
= page_lru(page
);
896 VM_BUG_ON_PAGE(PageLRU(page
), page
);
899 add_page_to_lru_list(page
, lruvec
, lru
);
900 update_page_reclaim_stat(lruvec
, file
, active
);
901 trace_mm_lru_insertion(page
, lru
);
905 * Add the passed pages to the LRU, then drop the caller's refcount
906 * on them. Reinitialises the caller's pagevec.
908 void __pagevec_lru_add(struct pagevec
*pvec
)
910 pagevec_lru_move_fn(pvec
, __pagevec_lru_add_fn
, NULL
);
912 EXPORT_SYMBOL(__pagevec_lru_add
);
915 * pagevec_lookup_entries - gang pagecache lookup
916 * @pvec: Where the resulting entries are placed
917 * @mapping: The address_space to search
918 * @start: The starting entry index
919 * @nr_entries: The maximum number of entries
920 * @indices: The cache indices corresponding to the entries in @pvec
922 * pagevec_lookup_entries() will search for and return a group of up
923 * to @nr_entries pages and shadow entries in the mapping. All
924 * entries are placed in @pvec. pagevec_lookup_entries() takes a
925 * reference against actual pages in @pvec.
927 * The search returns a group of mapping-contiguous entries with
928 * ascending indexes. There may be holes in the indices due to
929 * not-present entries.
931 * pagevec_lookup_entries() returns the number of entries which were
934 unsigned pagevec_lookup_entries(struct pagevec
*pvec
,
935 struct address_space
*mapping
,
936 pgoff_t start
, unsigned nr_pages
,
939 pvec
->nr
= find_get_entries(mapping
, start
, nr_pages
,
940 pvec
->pages
, indices
);
941 return pagevec_count(pvec
);
945 * pagevec_remove_exceptionals - pagevec exceptionals pruning
946 * @pvec: The pagevec to prune
948 * pagevec_lookup_entries() fills both pages and exceptional radix
949 * tree entries into the pagevec. This function prunes all
950 * exceptionals from @pvec without leaving holes, so that it can be
951 * passed on to page-only pagevec operations.
953 void pagevec_remove_exceptionals(struct pagevec
*pvec
)
957 for (i
= 0, j
= 0; i
< pagevec_count(pvec
); i
++) {
958 struct page
*page
= pvec
->pages
[i
];
959 if (!radix_tree_exceptional_entry(page
))
960 pvec
->pages
[j
++] = page
;
966 * pagevec_lookup_range - gang pagecache lookup
967 * @pvec: Where the resulting pages are placed
968 * @mapping: The address_space to search
969 * @start: The starting page index
970 * @end: The final page index
971 * @nr_pages: The maximum number of pages
973 * pagevec_lookup_range() will search for and return a group of up to @nr_pages
974 * pages in the mapping starting from index @start and upto index @end
975 * (inclusive). The pages are placed in @pvec. pagevec_lookup() takes a
976 * reference against the pages in @pvec.
978 * The search returns a group of mapping-contiguous pages with ascending
979 * indexes. There may be holes in the indices due to not-present pages. We
980 * also update @start to index the next page for the traversal.
982 * pagevec_lookup_range() returns the number of pages which were found. If this
983 * number is smaller than @nr_pages, the end of specified range has been
986 unsigned pagevec_lookup_range(struct pagevec
*pvec
,
987 struct address_space
*mapping
, pgoff_t
*start
, pgoff_t end
)
989 pvec
->nr
= find_get_pages_range(mapping
, start
, end
, PAGEVEC_SIZE
,
991 return pagevec_count(pvec
);
993 EXPORT_SYMBOL(pagevec_lookup_range
);
995 unsigned pagevec_lookup_range_tag(struct pagevec
*pvec
,
996 struct address_space
*mapping
, pgoff_t
*index
, pgoff_t end
,
999 pvec
->nr
= find_get_pages_range_tag(mapping
, index
, end
, tag
,
1000 PAGEVEC_SIZE
, pvec
->pages
);
1001 return pagevec_count(pvec
);
1003 EXPORT_SYMBOL(pagevec_lookup_range_tag
);
1005 unsigned pagevec_lookup_range_nr_tag(struct pagevec
*pvec
,
1006 struct address_space
*mapping
, pgoff_t
*index
, pgoff_t end
,
1007 int tag
, unsigned max_pages
)
1009 pvec
->nr
= find_get_pages_range_tag(mapping
, index
, end
, tag
,
1010 min_t(unsigned int, max_pages
, PAGEVEC_SIZE
), pvec
->pages
);
1011 return pagevec_count(pvec
);
1013 EXPORT_SYMBOL(pagevec_lookup_range_nr_tag
);
1015 * Perform any setup for the swap system
1017 void __init
swap_setup(void)
1019 unsigned long megs
= totalram_pages
>> (20 - PAGE_SHIFT
);
1021 /* Use a smaller cluster for small-memory machines */
1027 * Right now other parts of the system means that we
1028 * _really_ don't want to cluster much more