Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933310Ab3IMOEa (ORCPT ); Fri, 13 Sep 2013 10:04:30 -0400 Received: from mail-wi0-f176.google.com ([209.85.212.176]:41421 "EHLO mail-wi0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932389Ab3IMOE2 (ORCPT ); Fri, 13 Sep 2013 10:04:28 -0400 Date: Fri, 13 Sep 2013 16:04:24 +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" , Peter Zijlstra , Ingo Molnar Subject: Re: [RFC] Restrict kernel spawning of threads to a specified set of cpus. Message-ID: <20130913140422.GE4844@somewhere> References: <000001411282afa6-fe9c0543-0447-492b-991e-dc8214884b88-000000@email.amazonses.com> <20130912141625.GA23357@somewhere> <00000141128d759a-44dcacb6-8f48-4f9b-8381-d14003bd6da1-000000@email.amazonses.com> <20130912143137.GA23839@somewhere> <0000014112a921ae-51d171bf-e8d4-4569-bd20-94dabda2d5ba-000000@email.amazonses.com> <20130912151102.GB23839@somewhere> <0000014112d66287-d0abaeb1-71ff-48a0-8740-f984d47400a7-000000@email.amazonses.com> <20130912183023.GA25386@somewhere> <00000141179222e5-8a10141c-7b95-4204-853c-ab266fd08532-000000@email.amazonses.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <00000141179222e5-8a10141c-7b95-4204-853c-ab266fd08532-000000@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: 1137 Lines: 24 On Fri, Sep 13, 2013 at 01:45:55PM +0000, Christoph Lameter wrote: > On Thu, 12 Sep 2013, Frederic Weisbecker wrote: > > > So yeah it's a problem in theory. Now in practice, I have yet to be convinced because > > this should be solved after a few iterations in /proc in most cases. > > I have seen some drivers regularly spawning threads all over the machnine. > This is a practical issue that I am addresing. > > > > Now the issue doesn't only concern kthreads but all tasks in the system. > > If we really want to solve that race, then may be we can think of a kernel_parameter > > that sets the initial affinity of init and then lets get it naturally inherited > > through the whole tree. > > This patch that we are discussing does exactly that. > Indeed, I just looked that again and your cpu_kthread_mask actually also applies to init. cpu_init_mask would be a better name I think. -- 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/