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Commit a978d6f5 authored by Nick Piggin's avatar Nick Piggin Committed by Linus Torvalds
Browse files

mm: unlockless reclaim 



unlock_page is fairly expensive.  It can be avoided in page reclaim
success path.  By definition if we have any other references to the page
it would be a bug anyway.

Signed-off-by: default avatarNick Piggin <npiggin@suse.de>
Reviewed-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent f45840b5

mm/vmscan.c

+8 −1
Original line number Diff line number Diff line
@@ -732,7 +732,14 @@ static unsigned long shrink_page_list(struct list_head *page_list, 
		if (!mapping || !__remove_mapping(mapping, page))

			goto keep_locked;



		unlock_page(page);

		/*

		 * At this point, we have no other references and there is

		 * no way to pick any more up (removed from LRU, removed

		 * from pagecache). Can use non-atomic bitops now (and

		 * we obviously don't have to worry about waking up a process

		 * waiting on the page lock, because there are no references.

		 */

		__clear_page_locked(page);

free_it:

		nr_reclaimed++;

		if (!pagevec_add(&freed_pvec, page)) {