Document statistics added in commits
commit a0d06486b4
Author: Denis V. Lunev <den@openvz.org>
Date: Wed Feb 24 10:50:48 2016 +0300
virtio-balloon: add 'available' counter
and
commit bf1e7140ef
Author: Tomáš Golembiovský <tgolembi@redhat.com>
Date: Tue Dec 5 13:14:46 2017 +0100
virtio-balloon: include statistics of disk/file caches
Signed-off-by: Tomáš Golembiovský <tgolembi@redhat.com>
Reviewed-by: Jonathan Helman <jonathan.helman@oracle.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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>
