Comment 25 for bug 1392176

@glaubits,

cgmanager is not for managing but for delegating cgroups, which systemd does not yet provide. (I'd like to work toward that with the systemd community) When that is not needed then cgmanager can indeed be removed - however cpusets still end up being mounted by systemd itself.

@bharata-rao

My reading of kernel/cpusets.c comments is that the new cpuset.effective_cpus is supposed to give you what you want. If you've written 0-64 into cpuset.cpus, and some cpus are removed, then cpuset.cpus won't be changed, only cpuset.effective_cpus. When you plug those cpus back in, then they should show back up in cpuset.effective_cpus.

I dont' have any hardware to test on, and couldn't get libvirt setvcpus to do this for me, but could you please test on a ubuntu 15.04 host (which should have a new enough kernel to have cpuset.effective_cpus)?