linux-kernel - Re: [PATCH v8 5/6] cgroup/cpuset: Update description of cpuset.cpus.partition in cgroup-v2.rst

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20211201141350.GA54766@blackbody.suse.cz>
Date:   Wed, 1 Dec 2021 15:13:50 +0100
From:   Michal Koutný <mkoutny@...e.com>
To:     Waiman Long <longman@...hat.com>
Cc:     Tejun Heo <tj@...nel.org>, Zefan Li <lizefan.x@...edance.com>,
        Johannes Weiner <hannes@...xchg.org>,
        Jonathan Corbet <corbet@....net>,
        Shuah Khan <shuah@...nel.org>, cgroups@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-doc@...r.kernel.org,
        linux-kselftest@...r.kernel.org,
        Andrew Morton <akpm@...ux-foundation.org>,
        Roman Gushchin <guro@...com>, Phil Auld <pauld@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Juri Lelli <juri.lelli@...hat.com>,
        Frederic Weisbecker <frederic@...nel.org>,
        Marcelo Tosatti <mtosatti@...hat.com>
Subject: Re: [PATCH v8 5/6] cgroup/cpuset: Update description of
 cpuset.cpus.partition in cgroup-v2.rst

On Tue, Nov 30, 2021 at 10:56:34PM -0500, Waiman Long <longman@...hat.com> wrote:
> > >      A valid parent partition may distribute out all its CPUs to
> > >      its child partitions as long as it is not the root cgroup and
> > >      there is no task associated with it.
> > A valid parent partition which isn't root never has tasks in them to begin
> > with.
> I believe there is some corner cases where it is possible to put task in an
> intermediate partition. That is why I put down this statement.

Just mind the threads -- cpuset controller is threaded and having tasks
in inner cgroup nodes is a real scenario. I wouldn't consider it a
corner case.

[ Actually, the paragraph could IMO be simplified:

> A valid parent partition may distribute out all its CPUs to
> its child partitions as long as there is no task associated with it.

Assuming there's always at least one kernel thread in the root cgroup
that can't be migrated anyway.]


Michal

Download attachment "signature.asc" of type "application/pgp-signature" (229 bytes)