On 07/03/2018 12:53 AM, Tejun Heo wrote: > Hello, Waiman. > > On Sun, Jun 24, 2018 at 03:30:38PM +0800, Waiman Long wrote: >> Because of the fact that setting the "cpuset.sched.partition" in >> a direct child of root can remove CPUs from the root's effective CPU >> list, it makes sense to know what CPUs are left in the root cgroup for >> scheduling purpose. So the "cpuset.cpus.effective" control file is now >> exposed in the v2 cgroup root. > So, effective changing when enabling partition on a child feels wrong > to me. It's supposed to contain what's actually allowed to the cgroup > from its parent and that shouldn't change regardless of how those > resources are used. It's still given to the cgroup from its parent. Another way to work around this issue is to expose the reserved_cpus in the parent for holding CPUs that can taken by a chid partition. That will require adding one more cpuset file for those cgroups that are partition roots. > It's a bit different because the way partition behaves is different > from other resource konbs in that it locks away those cpus so that > they can't be taken back. > > What do people think about restricting partition to the first level > children for now at least? That way we aren't locked into the special > semantics and we can figure out how to this down the hierarchy later. > Given that we ignore the regular cpuset settings when the set goes > empty (which also is a special condition which only exists for cpuset) > and inherits the parent's, I think the consistent thing to do is doing > the same for partition - if it can't be satisfied, ignore it, but > maybe there is a better way. I don't mind restricting that to the first level children for now. That does restrict where we can put the container root if we want a separate partition for a container. Let's hear if others have any objection about that. Cheers, Longman -- To unsubscribe from this list: send the line "unsubscribe cgroups" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
