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Subject: Re: [PATCH v6 2/2] cpuset: Add cpuset.sched_load_balance to v2
To: Tejun Heo <tj@kernel.org>
Cc: Juri Lelli <juri.lelli@redhat.com>, Li Zefan <lizefan@huawei.com>,
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From: Waiman Long <longman@redhat.com>
Organization: Red Hat
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Date: Tue, 27 Mar 2018 10:23:33 -0400
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On 03/27/2018 10:02 AM, Tejun Heo wrote:
> Hello,
>
> On Mon, Mar 26, 2018 at 04:28:49PM -0400, Waiman Long wrote:
>> Maybe we can have a different root level flag, say,
>> sched_partition_domain that is equivalent to !sched_load_balnace.
>> However, I am still not sure if we should enforce that no task should be
>> in the root cgroup when the flag is set.
>>
>> Tejun and Peter, what are your thoughts on this?
> I haven't looked into the other issues too much but we for sure cannot
> empty the root cgroup.
>
> Thanks.
>
Now, I have a different idea. How about we add a special root-only knob,
say, "cpuset.cpus.isolated" that contains the list of CPUs that are
still owned by root, but not participated in load balancing. All the
tasks in the root are load-balanced among the remaining CPUs.

A child can then be created that hold some or all the CPUs in the
isolated set. It will then have a separate root domain if load balancing
is on, or an isolated cpuset if load balancing is off.

Will that idea work?

Cheers,
Longman