Re: [PATCH v9 2/7] cgroup/cpuset: Allow no-task partition to have empty cpuset.cpus.effective
From: Michal Koutný <mkoutny@suse.com>
Date: 2021-12-15 10:36:35
Also in:
cgroups, linux-kselftest, lkml
On Tue, Dec 14, 2021 at 10:24:22PM -0500, Waiman Long [off-list ref] wrote:
AFAICS, there are code in cpuset.c that disallows the an non-child node to hold tasks, but the check doesn't cover all the possible cases. I remembered that I was able to create such a scenario without using threaded domains.
On the default hierarchy (with controller(s) enabled)? That sounds like a bug.
That is why I put in this conditional check. It has nothing to do with the use of threaded domains.
But threaded domains are important nevertheless. I think that a structure like app-cgroup cgroup.type=threaded domain cpuset.partition=root `- rt cgroup.type=threaded cpuset.partition=isolated `- normal cgroup.type=threaded is a valid use case. Therefore I would not disallow partitioning inside threaded subtrees (as suggested). Michal