On Wed, Dec 5, 2012 at 4:44 PM, Andrey Korolyov <andrey(a)xdel.ru> wrote:
Hi,
Since this
message(https://www.redhat.com/archives/libvirt-users/2012-October/msg000...
qemu folks have released one minor version in the 1.2 branch and shiny
new 1.3 some days ago and the problem still persists. At first I has
blamed libvirt, but I was not correct at all - since I have released
package ``slices'' for myself including both newer libvirth and qemu,
I wasn`t able to corner this problem and my report may be counted as
completely wrong.
Right now, I have the following situation:
- all libvirt versions running above qemu-1.1 always reports right
balloon and currentMemory sizes
- for qemu 1.2 it is quite more funny: as in message above, I receive
wrong currentMemory always set to ``magic'' 5398528kB at the 8gb host
node, but only if ``memory'' parameter has same or higher value, even
<memory unit='KiB'>5348520</memory> works okay, providing righ
balloon
value for the libvirt. As you can see the ~2700MB offset between
current and maximum(or entire host) memory present in both
configurations. 8Gb node is a simple non-numa machine so this is not
related to numa miscalculation. Previous test at the link above
processed on the 64GB two-head node with symmetric numa topology, if
it matters.
And finally,
$ virsh dumpxml vm010-000-000-092 | grep curr
<currentMemory unit='KiB'>5398528</currentMemory>
$ virsh qemu-monitor-command --hmp vm010-000-000-092 info balloon
balloon: actual=1176
Until virtio_balloon initializes in the guest, libvirt reporting
_right_ value for some seconds after VM start, so bug (which I unable
to track by myself) almost for sure presented in parsing of received
values from guest balloon.
Sorry, forgot to add - in both cases I have tested small vms with size
about 1Gb of RAM. On 8G node raising currentMemory to 2.5G and higher
results to right values, but for 64G machine it was not the same -
even 10Gb value had been reported wrong. At the first glance overall
amount of the host memory also may stepped into this problem, any
suggestions are welcome!