----- Original Message ----- > From: "Dan Kenigsberg" <dan...@redhat.com> > To: "Gal Hammer" <gham...@redhat.com> > Cc: vdsm-devel@lists.fedorahosted.org > Sent: Sunday, April 29, 2012 7:19:10 AM > Subject: Re: [vdsm] reserve virtio-balloon device created by libvirt > > On Mon, Apr 23, 2012 at 04:00:55PM +0300, Gal Hammer wrote: > > On 23/04/2012 12:26, Mark Wu wrote: > > >Hi guys, > > > > > >I saw that an option to create balloon device was added by Gal in > > >http://gerrit.ovirt.org/1573 > > >I have a question about it. Why don we preserve the old default > > >behaviour? I know it's not supported by ovirt-engine now, but I > > >can't > > >figure out what will break if it's not disabled explicitly. So do > > >you > > >think we can just make use of the balloon device added by libvirt? > > > > We didn't change the old behavior. > > > > Libvirt creates by default a memory-balloon device, so vdsm > > defaults > > was to disable it by adding a "none"-type device. This was done > > because vdsm didn't include an option to add such device. > > > > My patch added an option to create a memory-balloon through vdsm. > > If > > the user didn't request to add the device, the behavior is same as > > before, disabling the memory-balloon. > > I feel that it would be best not to flip Vdsm's default at the > moment, > even though it is the opposite of libvirt's. I would consider to flip > them only after your (Mark's) patches are in, tested, and proven > worthwhile for the common case. > > Currently, without any management for the balloon, reserving a guest > PCI > device was deemed wasteful.
On the other side of the fence - We know that we do need to do ballooning - In the (next?) release we'll end up adding this support - There's no harm (see next point) in adding the device now in fact it saves a config change on upgrade. - While it takes up a PCI slot it's going to be very, very rare deployments that will ever see the limit, libvirt/virtmanager/virt-install has done this forever without seeing push back. > > Regards, > > Dan. > > > > _______________________________________________ > vdsm-devel mailing list > vdsm-devel@lists.fedorahosted.org > https://fedorahosted.org/mailman/listinfo/vdsm-devel > _______________________________________________ vdsm-devel mailing list vdsm-devel@lists.fedorahosted.org https://fedorahosted.org/mailman/listinfo/vdsm-devel
