Virtualization and HotPlugging/swapping

[Amit Shah]

On (Fri) Jan 21 2011 [22:01:39], Daniel P. Berrange wrote:
> > 
> > CPU UnPlugging is not considered as a needed feature is it?
> > http://www.linux-kvm.org/page/CPUHotPlug
> > "Hot-unplug does not work, and actually, does not even make that much sense."
> 
> I wouldn't neccessarily agree with the statement on
> that page. I think it is perfectly valid to be able
> to want to unplug CPUs. If you have a 4 CPU guest on
> a 4 CPU host, and need to migrate the guest to a 2
> CPU host, then it could well be a better idea to
> unplug 2 of the guest CPUs than leave it overcommitted.
> Thus I expect someone will make hot-unplug work eventually

One can always offline the CPUs from within the guest.  In any case, CPU
hot-unplug requires cooperation from the guest so offlining isn't any
different.

		Amit
-- 
http://log.amitshah.net/