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| author | Nick Piggin <npiggin@suse.de> | 2008-10-18 20:26:58 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-10-20 08:52:32 -0700 |
| commit | a978d6f521063514812a7094dbe5036e056e4de3 (patch) | |
| tree | aaaed7caff558d8f9676f8cfd16b50ae6ca99573 /mm/vmscan.c | |
| parent | f45840b5c128445da70e7ec33adc47b4a12bdaf4 (diff) | |
| download | lwn-a978d6f521063514812a7094dbe5036e056e4de3.tar.gz lwn-a978d6f521063514812a7094dbe5036e056e4de3.zip | |
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/vmscan.c')
| -rw-r--r-- | mm/vmscan.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c index 412d7872fc75..3b5860294bb6 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)) { |