Re: [Qemu-devel] [PATCH 1/1] virtio-balloon: reset the statistic timer to load device

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

On Tue, Mar 29, 2016 at 05:00:49PM +0300, Denis V. Lunev wrote:
> From: Pavel Butsykin <pbutsykin@virtuozzo.com>
> 
> If before loading snapshot we had set the timer of statistics, then after
> applying snapshot the expiry time would be irrelevant for the restored
> state of the virtual clocks. A simple fix is just to restart the timer
> after loading snapshot.
> 
> For the user it may look like a long delay of statistics update after switch
> to the snapshot.
> 
> Signed-off-by: Pavel Butsykin <pbutsykin@virtuozzo.com>
> Reviewed-by: Roman Kagan <rkagan@virtuozzo.com>
> Signed-off-by: Denis V. Lunev <den@openvz.org>
> CC: Michael S. Tsirkin <mst@redhat.com>

I'm inclined to think we really should migrate the timer,
otherwise user might wait twice as long as expected ...

> ---
>  hw/virtio/virtio-balloon.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c
> index 22ad25c..c74101e 100644
> --- a/hw/virtio/virtio-balloon.c
> +++ b/hw/virtio/virtio-balloon.c
> @@ -426,6 +426,10 @@ static int virtio_balloon_load_device(VirtIODevice *vdev, QEMUFile *f,
>  
>      s->num_pages = qemu_get_be32(f);
>      s->actual = qemu_get_be32(f);
> +
> +    if (balloon_stats_enabled(s)) {
> +        balloon_stats_change_timer(s, s->stats_poll_interval);
> +    }
>      return 0;
>  }
>  
> -- 
> 2.1.4