Re: [PATCH v11 7/9] cpuset: Expose cpus.effective and mems.effective on cgroup v2 root

From: Waiman Long
Date: Fri Aug 17 2018 - 21:04:30 EST

On 08/17/2018 11:59 AM, Tejun Heo wrote:
> Hello, Waiman.
> On Mon, Aug 13, 2018 at 01:56:15PM -0400, Waiman Long wrote:
>> The following restrictions are still imposed on a partition root wrt
>> allowable changes in cpuset.cpus:
>> 1) cpuset.cpus cannot be set to "". There must be at least 1 cpu there.
>> 2) Adding cpus that are not in parent's cpuset.cpus (as well as
>> cpuset.cpus.effective) or that will take all the parent's effective cpus
>> away is not allowed.
>> So are these limitations acceptable?
>> The easiest way to remove those restrictions is to forcefully turn off
>> the cpuset.sched.partition flag in the cpuset as well as any
>> sub-partitions when the user try to do that. With that change, there
>> will be no more new restriction on what you can do on cpuset.cpus.
> I think that'd be the right thing to do. That's what we do with
> cpuset.cpus and cpuset.mems too. If there's nothing available, we
> ignore the config and show the settings which are currently in effect.
> Thanks.
Thanks! I will send out an updated patch after the 4.19 merge window closes.