From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760528AbZBDVyw (ORCPT ); Wed, 4 Feb 2009 16:54:52 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756062AbZBDVyn (ORCPT ); Wed, 4 Feb 2009 16:54:43 -0500 Received: from mx3.mail.elte.hu ([157.181.1.138]:53913 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754184AbZBDVym (ORCPT ); Wed, 4 Feb 2009 16:54:42 -0500 Date: Wed, 4 Feb 2009 22:54:19 +0100 From: Ingo Molnar To: Andrew Morton Cc: rusty@rustcorp.com.au, travis@sgi.com, mingo@redhat.com, davej@redhat.com, cpufreq@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/3] work_on_cpu: Use our own workqueue. Message-ID: <20090204215419.GA28629@elte.hu> References: <20090116191108.135927000@polaris-admin.engr.sgi.com> <200902041314.32277.rusty@rustcorp.com.au> <20090203190111.2ec31cef.akpm@linux-foundation.org> <200902042111.35543.rusty@rustcorp.com.au> <20090204073636.30f15339.akpm@linux-foundation.org> <20090204213519.GR22608@elte.hu> <20090204134823.8eefa728.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090204134823.8eefa728.akpm@linux-foundation.org> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Andrew Morton wrote: > On Wed, 4 Feb 2009 22:35:19 +0100 > Ingo Molnar wrote: > > > > > * Andrew Morton wrote: > > > > > mm/pdflush.c: > > > > > > wtf what the heck is all that stuff and who added it? weird. > > > > > > Leave it alone I guess. Can admins manually move kernel threads to > > > other CPUs? > > > > they can - and there's even tools that do that (there's some -rt tools where > > you can put kernel thread priorities into a config file). > > > > Oh well, DontDoThatThen. > > I expect that the same argument applies to most of the set_cpus_allowed() > callsites - they're run by root-only code. Sure, root can (with > careful timing) move root's own thread onto the wrong CPU in the middle > of microcode loading. In which case root gets to own both pieces. > > We only really need to worry about the places where non-root code can > run set_cpus_allowed(). And then we only need to worry a little bit. > > Yes? Given the alternatives i suspect the best answer is a yes :) Ingo