Re: [libvirt] [PATCH] allow memballoon type of none to desactivate it
On Mon, Aug 09, 2010 at 06:38:27PM +0200, Daniel Veillard wrote:
The balloon device is automatically added to qemu guests if
supported,
but it may be useful to desactivate it. The simplest to not change the
existing behaviour is to allow
<memballoon type="none"/>
as an extra option to desactivate it (it is automatically added if the
memballoon construct is missing for the domain).
The following simple patch just adds the extra option and does not
change the default behaviour but avoid creating a balloon device if
type="none" is used.
I really don't like the idea of 'type=none' devices in general.
I don't think we should have an element insides <devices> that
doesn't actually represent a device.
If we want to disable the balloon, then I think we should aim
for an element or attribute elsewhere to toggle it.
eg, perhaps the earlier <memory> element can indicate whether it
supports ballooning. eg
<memory ballonable='yes|no'>2423423432</memory>
Thus if ballooning is not enabled, the <memballoon> device would
never need to appear within <devices>
P.S.: there is also a XEN type uspposedly for xen but I was unable
to
find any baloon code in our current xen driver so no change there
Xen always has a balloon device, so we should make Xen driver always add
the <memballoon> device.
Daniel
--
|: Red Hat, Engineering, London -o- http://people.redhat.com/berrange/ :|
|: http://libvirt.org -o- http://virt-manager.org -o- http://deltacloud.org :|
|: http://autobuild.org -o- http://search.cpan.org/~danberr/ :|
|: GnuPG: 7D3B9505 -o- F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 :|