From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:52941) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Wn63S-00057a-0P for qemu-devel@nongnu.org; Wed, 21 May 2014 08:55:38 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Wn63M-00043F-Tn for qemu-devel@nongnu.org; Wed, 21 May 2014 08:55:33 -0400 Received: from mx1.redhat.com ([209.132.183.28]:11489) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Wn63M-00042x-Kq for qemu-devel@nongnu.org; Wed, 21 May 2014 08:55:28 -0400 Date: Wed, 21 May 2014 15:54:19 +0300 From: "Michael S. Tsirkin" Message-ID: <20140521125419.GB21476@redhat.com> References: <337a4c88f373a56ca30698bf1f8772467ddb347d.1400662668.git.jtomko@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <337a4c88f373a56ca30698bf1f8772467ddb347d.1400662668.git.jtomko@redhat.com> Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH v2] virtio-balloon: return empty data when no stats are available List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: =?iso-8859-1?B?SuFu?= Tomko Cc: qemu-devel@nongnu.org, aliguori@amazon.com, lcapitulino@redhat.com On Wed, May 21, 2014 at 11:03:47AM +0200, J=E1n Tomko wrote: > If the guest hasn't updated the stats yet, instead of returning > an error, return '-1' for the stats and '0' as 'last-update'. >=20 > This lets applications ignore this without parsing the error message. >=20 > Related libvirt patch and discussion: > https://www.redhat.com/archives/libvir-list/2014-May/msg00460.html >=20 > 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) >=20 > Signed-off-by: J=E1n Tomko Applied, thanks! > --- > v1: https://lists.gnu.org/archive/html/qemu-devel/2014-05/msg03643.html > Reviewed-by: Eric Blake > v2: > rebased > added documentation changes > mentioned testing in the commit message >=20 > docs/virtio-balloon-stats.txt | 5 +++-- > hw/virtio/virtio-balloon.c | 7 ++----- > 2 files changed, 5 insertions(+), 7 deletions(-) >=20 > diff --git a/docs/virtio-balloon-stats.txt b/docs/virtio-balloon-stats.= txt > 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 hos= t, > - a buggy guest can't influence its value > + a buggy guest can't influence its value. The value is 0 if the gue= st > + 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 ca= se > - 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 > 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, str= uct 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(DeviceSta= te *dev, Error **errp) > s->dvq =3D virtio_add_queue(vdev, 128, virtio_balloon_handle_outpu= t); > s->svq =3D virtio_add_queue(vdev, 128, virtio_balloon_receive_stat= s); > =20 > + reset_stats(s); > + > register_savevm(dev, "virtio-balloon", -1, 1, > virtio_balloon_save, virtio_balloon_load, s); > =20 > --=20 > 1.8.3.2