From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:37951) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WsbHp-0004lt-2F for qemu-devel@nongnu.org; Thu, 05 Jun 2014 13:17:16 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WsbHg-0007ds-N3 for qemu-devel@nongnu.org; Thu, 05 Jun 2014 13:17:09 -0400 Received: from mx1.redhat.com ([209.132.183.28]:61181) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WsbHg-0007d2-Ea for qemu-devel@nongnu.org; Thu, 05 Jun 2014 13:17:00 -0400 Date: Thu, 5 Jun 2014 20:17:25 +0300 From: "Michael S. Tsirkin" Message-ID: <1401986505-12359-7-git-send-email-mst@redhat.com> References: <1401986505-12359-1-git-send-email-mst@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <1401986505-12359-1-git-send-email-mst@redhat.com> Content-Transfer-Encoding: quoted-printable Subject: [Qemu-devel] [PULL 06/10] virtio-balloon: return empty data when no stats are available List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Peter Maydell , =?us-ascii?B?PT9VVEYtOD9xP0o9QzM9QTFuPTIwVG9ta28/PQ==?= , Anthony Liguori From: J=E1n Tomko If the guest hasn't updated the stats yet, instead of returning an error, return '-1' for the stats and '0' as 'last-update'. This lets applications ignore this without parsing the error message. Related libvirt patch and discussion: https://www.redhat.com/archives/libvir-list/2014-May/msg00460.html Tested against current upstream libvirt - stat reporting works and it no longer logs errors when the stats are queried on domain startup. (Note: libvirt doesn't use the last-update field for anything yet) Signed-off-by: J=E1n Tomko Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin Reviewed-by: Eric Blake --- hw/virtio/virtio-balloon.c | 7 ++----- docs/virtio-balloon-stats.txt | 5 +++-- 2 files changed, 5 insertions(+), 7 deletions(-) diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c index bf2b588..22cd52e 100644 --- a/hw/virtio/virtio-balloon.c +++ b/hw/virtio/virtio-balloon.c @@ -112,11 +112,6 @@ static void balloon_stats_get_all(Object *obj, struc= t Visitor *v, VirtIOBalloon *s =3D opaque; int i; =20 - if (!s->stats_last_update) { - error_setg(errp, "guest hasn't updated any stats yet"); - return; - } - visit_start_struct(v, NULL, "guest-stats", name, 0, &err); if (err) { goto out; @@ -378,6 +373,8 @@ static void virtio_balloon_device_realize(DeviceState= *dev, Error **errp) s->dvq =3D virtio_add_queue(vdev, 128, virtio_balloon_handle_output)= ; s->svq =3D virtio_add_queue(vdev, 128, virtio_balloon_receive_stats)= ; =20 + reset_stats(s); + register_savevm(dev, "virtio-balloon", -1, 1, virtio_balloon_save, virtio_balloon_load, s); =20 diff --git a/docs/virtio-balloon-stats.txt b/docs/virtio-balloon-stats.tx= t index f74612f..edff5f2 100644 --- a/docs/virtio-balloon-stats.txt +++ b/docs/virtio-balloon-stats.txt @@ -35,7 +35,8 @@ which will return a dictionary containing: =20 o A key named last-update, which contains the last stats update timestamp in seconds. Since this timestamp is generated by the host, - a buggy guest can't influence its value + a buggy guest can't influence its value. The value is 0 if the guest + has not updated the stats (yet). =20 It's also important to note the following: =20 @@ -49,7 +50,7 @@ It's also important to note the following: =20 - Polling can be enabled even if the guest doesn't have stats support or the balloon driver wasn't loaded in the guest. If this is the case - and stats are queried, an error will be returned + and stats are queried, last-update will be 0. =20 - The polling timer is only re-armed when the guest responds to the statistics request. This means that if a (buggy) guest doesn't ever --=20 MST