Re: [libvirt] [PATCH v5 2/2] conf: List only online cpus for virsh emulatorpin

On Tue, Dec 06, 2016 at 13:01:48 +0100, Viktor Mihajlovski wrote: > On 06.12.2016 12:33, Peter Krempa wrote: >> On Fri, Nov 25, 2016 at 14:53:07 +0530, Nitesh Konkar wrote: [...] >> Additionally we historically treat the "all bits set" cpu map >> as that there is no pinning configured. This would change this >> behavior. When the VM is started, the real cpu map should be >> returned, but for the config time I think the current state is >> correct and doing your change would be incorrect. > I have no strong opinion on whether the CPU mask should match the > host online mask for the defined case, but the "all bits set" map > will change with the old code as well, if new CPUs are added via > hotplug. CPU hotplug on the host is very uncommon and thus not tested very well.

> The crux is that we don't have any way to find out there's in > fact no pinning in place for a process nor a way to "unpin" it. That is true indeed. It's not possible via the API. It's fully possible via XML though. For unpinning I have an unfinished series adding a flag to remove pinning since since any other method is not reliable enough. Finally I think that the "all ones" bitmap should cover the full map the user sends to libvirt. This would differentiate it from the "pinned to current full set of cpus" case.