swap: prevent reuse during hibernation
authorHugh Dickins <hughd@google.com>
Thu, 9 Sep 2010 23:38:09 +0000 (16:38 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Fri, 10 Sep 2010 01:57:25 +0000 (18:57 -0700)
commitb73d7fcecd93dc15eaa3c45c8c587b613f6673c4
treeebf5a5e10fb246237807317a81f6f40c3eebcd9c
parent910321ea817a202ff70fac666e37e2c8e2f88823
swap: prevent reuse during hibernation

Move the hibernation check from scan_swap_map() into try_to_free_swap():
to catch not only the common case when hibernation's allocation itself
triggers swap reuse, but also the less likely case when concurrent page
reclaim (shrink_page_list) might happen to try_to_free_swap from a page.

Hibernation already clears __GFP_IO from the gfp_allowed_mask, to stop
reclaim from going to swap: check that to prevent swap reuse too.

Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Ondrej Zary <linux@rainbow-software.org>
Cc: Andrea Gelmini <andrea.gelmini@gmail.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Nigel Cunningham <nigel@tuxonice.net>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/swapfile.c