Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753436AbbDII3j (ORCPT ); Thu, 9 Apr 2015 04:29:39 -0400 Received: from casper.infradead.org ([85.118.1.10]:52949 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751565AbbDII3e (ORCPT ); Thu, 9 Apr 2015 04:29:34 -0400 Date: Thu, 9 Apr 2015 10:29:21 +0200 From: Peter Zijlstra To: Chris Metcalf Cc: Frederic Weisbecker , "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: <20150409082921.GP27490@worktop.programming.kicks-ass.net> 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> <20150408172746.GK5029@twins.programming.kicks-ass.net> <55256F92.1010606@ezchip.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <55256F92.1010606@ezchip.com> User-Agent: Mutt/1.5.22.1 (2013-10-16) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 876 Lines: 30 On Wed, Apr 08, 2015 at 02:12:34PM -0400, Chris Metcalf wrote: > >But you're doing the reverse! You're setting nohz_full for isolcpus, not > >limiting the nohz_full mask to isolcpus. > > Ah, I see. Yes, that's right. No its not, you should correct me when I'm wrong ;-) So the problem is that: + tick_nohz_full_set_cpus(cpu_isolated_map); reads like you're doing: nohz_full_map |= isolcpus_map But in actual fact you're doing: isolcpus_map |= nohz_full_map So that function is retarded, but the logic is fine. So NAK on both patches for the reason that they're utterly confusing as to wtf they actually do. -- 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/