Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753428Ab3ILObn (ORCPT ); Thu, 12 Sep 2013 10:31:43 -0400 Received: from mail-wi0-f173.google.com ([209.85.212.173]:57975 "EHLO mail-wi0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751034Ab3ILObm (ORCPT ); Thu, 12 Sep 2013 10:31:42 -0400 Date: Thu, 12 Sep 2013 16:31:38 +0200 From: Frederic Weisbecker To: Christoph Lameter Cc: Andrew Morton , Gilad Ben-Yossef , Thomas Gleixner , Mike Frysinger , linux-kernel@vger.kernel.org, "Paul E. McKenney" Subject: Re: [RFC] Restrict kernel spawning of threads to a specified set of cpus. Message-ID: <20130912143137.GA23839@somewhere> References: <00000140efbcb701-c26320b3-f434-4538-bc80-8e92fed6f303-000000@email.amazonses.com> <20130911220228.GB15367@somewhere> <000001411282afa6-fe9c0543-0447-492b-991e-dc8214884b88-000000@email.amazonses.com> <20130912141625.GA23357@somewhere> <00000141128d759a-44dcacb6-8f48-4f9b-8381-d14003bd6da1-000000@email.amazonses.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <00000141128d759a-44dcacb6-8f48-4f9b-8381-d14003bd6da1-000000@email.amazonses.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1014 Lines: 26 On Thu, Sep 12, 2013 at 02:22:43PM +0000, Christoph Lameter wrote: > On Thu, 12 Sep 2013, Frederic Weisbecker wrote: > > > On Thu, Sep 12, 2013 at 02:10:56PM +0000, Christoph Lameter wrote: > > > On Thu, 12 Sep 2013, Frederic Weisbecker wrote: > > > > > > > Why not do this from userspace instead? > > > > > > Because the cpumasks are hardcoded in the kernel code. > > > > > > > Ok but you can change the affinity of a kthread from userspace, as > > long as you define a cpu set that is among that kthread's cpus allowed. > > Ok but at that point kthread has already spawned a lot of kernel threads. > > The same is true for init and kmod. > Ok but then we just need to set the affinity of all these kthreads. A simple lookup on /proc/[0-9]+/ should do the trick. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/