Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754303AbbDHRYf (ORCPT ); Wed, 8 Apr 2015 13:24:35 -0400 Received: from mail-wg0-f52.google.com ([74.125.82.52]:33255 "EHLO mail-wg0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754140AbbDHRYc (ORCPT ); Wed, 8 Apr 2015 13:24:32 -0400 Date: Wed, 8 Apr 2015 19:24:26 +0200 From: Frederic Weisbecker To: Chris Metcalf Cc: Peter Zijlstra , "Paul E. McKenney" , "Rafael J. Wysocki" , Martin Schwidefsky , Ingo Molnar , linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 2/2] nohz: make nohz_full imply isolcpus Message-ID: <20150408172424.GC13227@lerouge> References: <5522BF1E.2040606@ezchip.com> <1428344205-27678-1-git-send-email-cmetcalf@ezchip.com> <1428344205-27678-2-git-send-email-cmetcalf@ezchip.com> <20150408094114.GX23123@twins.programming.kicks-ass.net> <5525357B.2080205@ezchip.com> <20150408142641.GG5029@twins.programming.kicks-ass.net> <55254794.4070503@ezchip.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <55254794.4070503@ezchip.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1743 Lines: 36 On Wed, Apr 08, 2015 at 11:21:56AM -0400, Chris Metcalf wrote: > On 04/08/2015 10:26 AM, Peter Zijlstra wrote: > >On Wed, Apr 08, 2015 at 10:04:43AM -0400, Chris Metcalf wrote: > >>On 04/08/2015 05:41 AM, Peter Zijlstra wrote: > >>>On Mon, Apr 06, 2015 at 02:16:45PM -0400, cmetcalf@ezchip.com wrote: > >>>>From: Chris Metcalf > >>>> > >>>>It's not clear that nohz_full is useful without isolcpus also > >>>>set, since otherwise the scheduler has to run periodically to > >>>>try to determine whether to steal work from other cores. > >>>So the Changelog and the patch don't seem to agree with one another. > >>> > >>>The Changelog states that nohz_full should depend on isolcpus. > >>The git commit message says "make nohz_full imply isolcpus". > >>That's consistent with the code. > >Well, but then the Changelog doesn't make any sense. > > Apparently the body of the commit message isn't as clear as it might be :-) > > It does say the same thing, though, basically that if nohz_full DOESN'T > imply isolcpus, that's a bad thing. I'm happy to reword the text to avoid > the double negative and say: > > nohz_full is only useful with isolcpus also set, since otherwise the > scheduler has to run periodically to try to determine whether to steal > work from other cores. > > Frederic, do you want me to respin the patch, or can you just update > the text of the commit message as above? Please respin. Writing or fixing changelogs is what takes me most time :-) -- 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/