[PATCH RFC] virtio_balloon: refill by config handler

["Michael S. Tsirkin" <mst@redhat.com>]

Peter Mladek reported that balloon might never refill completely after
restore.  This is because fill_balloon is only called once there.
Calling fill_balloon repeatedly seems too aggressive,
especially in light of the fact that it sleeps on failure: let's
wake the config change handler and fill it asynchronously.

Reported-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---

I was unable to test this - for some reason my test VM
doesn't resume (with or without the patch).
Petr, does this work for you?

 drivers/virtio/virtio_balloon.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index 7efc329..ee29473 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -589,7 +589,7 @@ static int virtballoon_restore(struct virtio_device *vdev)
 
 	virtio_device_ready(vdev);
 
-	fill_balloon(vb, towards_target(vb));
+	wake_up(&vb->config_change);
 	update_balloon_size(vb);
 	return 0;
 }
-- 
MST