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| author | Ján Tomko <jtomko@redhat.com> | 2014-05-21 11:03:47 +0200 |
|---|---|---|
| committer | Michael S. Tsirkin <mst@redhat.com> | 2014-05-25 12:46:58 +0300 |
| commit | 38dbd48b247ebe05bdc6ef52ccdc60cc21274877 (patch) | |
| tree | e3294ac81369b393769a51b9d41fb4c9384a9d3e | |
| parent | 7c8b7248261bfa5e54eff1715b699caa8b3f1d77 (diff) | |
| download | focaccia-qemu-38dbd48b247ebe05bdc6ef52ccdc60cc21274877.tar.gz focaccia-qemu-38dbd48b247ebe05bdc6ef52ccdc60cc21274877.zip | |
virtio-balloon: return empty data when no stats are available
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 <jtomko@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
| -rw-r--r-- | docs/virtio-balloon-stats.txt | 5 | ||||
| -rw-r--r-- | 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 f74612f468..edff5f22a8 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 bf2b588b24..22cd52edee 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); |