[Qemu-devel] Re: [PATCH] Disable virtio-balloon memory stats interface

[Amit Shah]

On (Mon) Aug 30 2010 [14:17:51], Adam Litke wrote:
> The addition of memory stats reporting to the virtio balloon causes
> the 'info balloon' command to become asynchronous.  This is a regression
> because management tools that consume this command were not designed to
> handle lost or delayed responses.
> 
> To fix this regression, the virtio balloon memory stats feature is being
> disabled in qemu-0.13.
> 
> Signed-off-by: Adam Litke <address@hidden>
> 
> diff --git a/hw/virtio-balloon.c b/hw/virtio-balloon.c
> index 9fe3886..2d80382 100644
> --- a/hw/virtio-balloon.c
> +++ b/hw/virtio-balloon.c
> @@ -190,7 +190,18 @@ static void virtio_balloon_set_config(VirtIODevice *vdev,
>  
>  static uint32_t virtio_balloon_get_features(VirtIODevice *vdev, uint32_t f)
>  {
> -    f |= (1 << VIRTIO_BALLOON_F_STATS_VQ);
> +    /*
> +     * The addition of memory stats reporting to the virtio balloon causes
> +     * the 'info balloon' command to become asynchronous.  This is a 
> regression
> +     * because management tools that consume this command were not designed 
> to
> +     * handle lost or delayed responses.

Rather, the monitor now gets stuck when it originally didn't.

> +     *
> +     * To fix this regression, the virtio balloon memory stats feature is 
> being
> +     * disabled in qemu-0.13.
> +     *
> +     * -aglitke
> +     */
> +    /* f |= (1 << VIRTIO_BALLOON_F_STATS_VQ); */
>      return f;
>  }

Acked-by: Amit Shah <address@hidden>

                Amit