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  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:   Wed, 19 Feb 2020 11:12:22 -0500
From:   Tejun Heo <tj@...nel.org>
To:     Mathieu Desnoyers <mathieu.desnoyers@...icios.com>
Cc:     Li Zefan <lizefan@...wei.com>, cgroups <cgroups@...r.kernel.org>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...nel.org>,
        Valentin Schneider <valentin.schneider@....com>,
        Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [regression] cpuset: offlined CPUs removed from affinity masks

On Wed, Feb 19, 2020 at 11:08:39AM -0500, Mathieu Desnoyers wrote:
> I wonder if applying the online cpu masks to the per-thread affinity mask
> is the correct approach ? I suspect what we may be looking for here is to keep

Oh, the whole thing is wrong.

> the affinity mask independent of cpu hotplug, and look-up both the per-thread
> affinity mask and the online cpu mask whenever the scheduler needs to perform
> "is_cpu_allowed()" to check task placement.

Yes, that's what it should have done from the get-go. The way it's
implemented now, maybe we can avoid some specific cases like cpuset
not being used at all but it'll constantly get in the way if you're
expecting thread affinity to retain its value across offlines.

-- 
tejun

Powered by blists - more mailing lists