In the page release paths, we can be sure that nobody will mess with our
page->flags because the refcount has dropped to 0.  So no need for atomic
operations here.
Signed-off-by: NNick Piggin <npiggin@suse.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>