Re: [libvirt] [PATCH] conf: Allow omitting of numa node memory size

On Tue, Feb 21, 2017 at 15:36:23 +0000, Daniel Berrange wrote: > On Tue, Feb 21, 2017 at 04:22:05PM +0100, Peter Krempa wrote: > > Memory-less numa nodes could be specified by setting the memory size to > > 0. Allow ommiting of the parameter completely to specify the same. > > > > Partially resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1217144 > > Does this correctly plumb through to the guest OS ? > > Last time we tried fixing this bug we found some problems - I can't remember > whether the problem was with 0 CPUs or 0 memory, but with one of them, QEMU > would totally mangle the NUMA topology, merging nodes together. I tried it and indeed the NUMA topology for a memory-less node shows up totally broken in the guest. From your comments on the linked bugzilla I thought that it worked properly if you specify memory='0' explicitly. Since cpu-less nodes are possible for a long time and with the new cpu-hotplug API you can select individual vcpus to hotplug according to the id I was under the impression that only the syntax-sugar stuff was necessary to cover everyting.