Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755920Ab3IPGCc (ORCPT ); Mon, 16 Sep 2013 02:02:32 -0400 Received: from merlin.infradead.org ([205.233.59.134]:41835 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754587Ab3IPGCa (ORCPT ); Mon, 16 Sep 2013 02:02:30 -0400 Date: Mon, 16 Sep 2013 08:02:10 +0200 From: Peter Zijlstra To: Christoph Lameter Cc: Frederic Weisbecker , Andrew Morton , Gilad Ben-Yossef , Thomas Gleixner , Mike Frysinger , linux-kernel@vger.kernel.org, "Paul E. McKenney" , Ingo Molnar Subject: Re: [RFC] Restrict kernel spawning of threads to a specified set of cpus. Message-ID: <20130916060210.GM21832@twins.programming.kicks-ass.net> References: <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> <20130913092553.GL31370@twins.programming.kicks-ass.net> <00000141179a5b1f-b94a8394-9e98-400c-ae7f-59cdcfce60a6-000000@email.amazonses.com> <20130913144008.GF21832@twins.programming.kicks-ass.net> <0000014117fb2ea3-ec97f4c4-344b-42c5-b27c-be876f723942-000000@email.amazonses.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <0000014117fb2ea3-ec97f4c4-344b-42c5-b27c-be876f723942-000000@email.amazonses.com> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 992 Lines: 21 On Fri, Sep 13, 2013 at 03:40:40PM +0000, Christoph Lameter wrote: > Hmmm... usermodehelper is based on workqueues. I guess this will > ultimately come down to modify the workqueue behavior for > WORK_CPU_UNBOUND? You don't need to keep it like that -- in fact I would suggest removing that dependency and creating an extra (explicit) unbound thread spawner that both usermodehelper and kworker can use for unbound threads. > If WORK_CPU_UNBOUND could mean to limit process execution to the affinity > of kthreadd then we are fine. No, kthreadd must stay clean, if must not have any affinity nor be part of any cgroup like thing. We must have means of spawning clean kthreads, therefore we need to create a new parent for these special cases. -- 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/