Re: [libvirt] cpuset / numa and qemu in TCG mode

On Mon, May 11, 2015 at 01:14:58PM +0200, Martin Kletzander wrote: > Determining this by version might not be reliable, but more > importantly working around bug in underlying software is something > that shouldn't be done at all IMHO. Let the maintainers backport > whatever needs to be done. I agree with you in an ideal world but there are times when we do need to add work arounds in $project_x to work around issues in $project_y. > >Ther nova side will be pretty easy regardless. > > > >I'd say the best solution would be to back port the 'fix' but that seems like a > >lot of effort given the number of distros and libvirt versions potentiall > >involved. > > > > If you want the fix to be distro-agnostic, there's nothing easier than > back-porting the fix into our upstream maintenance branches. Those > should make the life of distro maintainers easy (although it looks > like not many distros use it). And this is part of the problem. If I understand correctly Ubuntu cloud-archive is using libvirt 1.2.12 which is *NOT* a maintenance release so that leaves us with doing an additional backport to 1.2.12 and getting the cloud-archive team to take it[1] or Adding a hack to nova. And that's just Ubuntu It's hard to say for sure that some vendor isn't running libvirt 1.2.12 also. > Having said that I'm not sure which commit(s) are those that need to > be back-ported. Having known your libvirt version, it shouldn't be > too hard looking for the differences and finding the right commit. > When back-porting request is made on the list, it is usually acted > upon. If you can't find the exact commit, let me know and I'll do my > best to help. So a git bisect points at: --- commit a103bb105c0c189c3973311ff1826972b5bc6ad6 Author: Daniel P. Berrange <berrange(a)redhat.com&gt; Date: Tue Feb 10 15:59:57 2015 +0000 qemu: fix setting of VM CPU affinity with TCG --- A small amount of reading implies to me that we'd be looking at backporting a103bb105c0c189c3973311ff1826972b5bc6ad6 to any maintenance branch that contains b07f3d821dfb11a118ee75ea275fd6ab737d9500. Which I think is 1.2.13 only, but I could be wrong. If you don't beat me to it I'll request that backport to 1.2.13 *and* ask the Ubuntu guys to take it as well. I have to admit I'm still in 2 minds on the nova side. Adding a wart to the libvirt driver for this specific bug for distros/vendors that are using 1.2.12 seems a bit gross but ....