On Wed, May 21, 2014 at 11:03:47AM +0200, Ján 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'. > > 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: Ján Tomko <jto...@redhat.com>
Applied, thanks! > --- > v1: https://lists.gnu.org/archive/html/qemu-devel/2014-05/msg03643.html > Reviewed-by: Eric Blake <ebl...@redhat.com> > v2: > rebased > added documentation changes > mentioned testing in the commit message > > docs/virtio-balloon-stats.txt | 5 +++-- > hw/virtio/virtio-balloon.c | 7 ++----- > 2 files changed, 5 insertions(+), 7 deletions(-) > > 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: > > 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). > > It's also important to note the following: > > @@ -49,7 +50,7 @@ It's also important to note the following: > > - 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. > > - 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, struct > Visitor *v, > VirtIOBalloon *s = opaque; > int i; > > - 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 = virtio_add_queue(vdev, 128, virtio_balloon_handle_output); > s->svq = virtio_add_queue(vdev, 128, virtio_balloon_receive_stats); > > + reset_stats(s); > + > register_savevm(dev, "virtio-balloon", -1, 1, > virtio_balloon_save, virtio_balloon_load, s); > > -- > 1.8.3.2
