diff options
| author | Rusty Russell <rusty@rustcorp.com.au> | 2014-03-13 11:23:38 +1030 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-05-13 13:59:41 +0200 |
| commit | 16440b5497cb3882d45b291147dbd61eb4951015 (patch) | |
| tree | c028e012f4ca306537f406d4dc21146b7f22cf7f | |
| parent | a93daee35a6d511e71f19c7227c64a9dc2c3e273 (diff) | |
virtio_balloon: don't softlockup on huge balloon changes.
commit 1f74ef0f2d7d692fcd615621e0e734c3e7771413 upstream.
When adding or removing 100G from a balloon:
BUG: soft lockup - CPU#0 stuck for 22s! [vballoon:367]
We have a wait_event_interruptible(), but the condition is always true
(more ballooning to do) so we don't ever sleep. We also have a
wait_event() for the host to ack, but that is also always true as QEMU
is synchronous for balloon operations.
Reported-by: Gopesh Kumar Chaudhary <gopchaud@in.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/virtio/virtio_balloon.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c index 71af7b5abe01..7d7add5ceba4 100644 --- a/drivers/virtio/virtio_balloon.c +++ b/drivers/virtio/virtio_balloon.c @@ -311,6 +311,12 @@ static int balloon(void *_vballoon) else if (diff < 0) leak_balloon(vb, -diff); update_balloon_size(vb); + + /* + * For large balloon changes, we could spend a lot of time + * and always have work to do. Be nice if preempt disabled. + */ + cond_resched(); } return 0; } |