diff options
| author | KAMEZAWA Hiroyuki | 2010-08-10 02:20:11 +0200 |
|---|---|---|
| committer | Linus Torvalds | 2010-08-10 05:45:04 +0200 |
| commit | d2997b1042ec150616c1963b5e5e919ffd0b0ebf (patch) | |
| tree | c970746ad3d5c3e0ccbd1695d07144dbe4534ec4 /kernel/power/snapshot.c | |
| parent | mm: fix corruption of hibernation caused by reusing swap during image saving (diff) | |
| download | kernel-qcow2-linux-d2997b1042ec150616c1963b5e5e919ffd0b0ebf.tar.gz kernel-qcow2-linux-d2997b1042ec150616c1963b5e5e919ffd0b0ebf.tar.xz kernel-qcow2-linux-d2997b1042ec150616c1963b5e5e919ffd0b0ebf.zip | |
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.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c index f6cd6faf84fd..5e7edfb05e66 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. */ |