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authorNick Piggin <npiggin@suse.de>2008-10-18 20:26:58 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-10-20 08:52:32 -0700
commita978d6f521063514812a7094dbe5036e056e4de3 (patch)
treeaaaed7caff558d8f9676f8cfd16b50ae6ca99573 /mm
parentf45840b5c128445da70e7ec33adc47b4a12bdaf4 (diff)
downloadconfigs-a978d6f521063514812a7094dbe5036e056e4de3.tar.gz
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: Nick Piggin <npiggin@suse.de> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/vmscan.c9
1 files changed, 8 insertions, 1 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 412d7872fc7..3b5860294bb 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -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)) {