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authorKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>2010-08-09 17:20:11 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2010-08-09 20:45:04 -0700
commitd2997b1042ec150616c1963b5e5e919ffd0b0ebf (patch)
treec970746ad3d5c3e0ccbd1695d07144dbe4534ec4 /kernel/power/snapshot.c
parent966cca029f739716fbcc8068b8c6dfe381f86fc3 (diff)
hibernation: freeze swap at hibernation
When taking a memory snapshot in hibernate_snapshot(), all (directly called) memory allocations use GFP_ATOMIC. Hence swap misusage during hibernation never occurs. But from a pessimistic point of view, there is no guarantee that no page allcation has __GFP_WAIT. It is better to have a global indication "we enter hibernation, don't use swap!". This patch tries to freeze new-swap-allocation during hibernation. (All user processes are frozenm so swapin is not a concern). This way, no updates will happen to swap_map[] between hibernate_snapshot() and save_image(). Swap is thawed when swsusp_free() is called. We can be assured that swap corruption will not occur. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Hugh Dickins <hughd@google.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Ondrej Zary <linux@rainbow-software.org> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/power/snapshot.c')
-rw-r--r--kernel/power/snapshot.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
index f6cd6faf84f..5e7edfb05e6 100644
--- a/kernel/power/snapshot.c
+++ b/kernel/power/snapshot.c
@@ -1086,6 +1086,7 @@ void swsusp_free(void)
buffer = NULL;
alloc_normal = 0;
alloc_highmem = 0;
+ hibernation_thaw_swap();
}
/* Helper functions used for the shrinking of memory. */