Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932071Ab3CZXs1 (ORCPT ); Tue, 26 Mar 2013 19:48:27 -0400 Received: from mail-la0-f41.google.com ([209.85.215.41]:44454 "EHLO mail-la0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757325Ab3CZXsW (ORCPT ); Tue, 26 Mar 2013 19:48:22 -0400 MIME-Version: 1.0 In-Reply-To: <20130325171844.GA3637@linux.vnet.ibm.com> References: <1363879460-21595-1-git-send-email-fweisbec@gmail.com> <20130324081701.GA13328@gmail.com> <20130325170257.GA24554@linux.vnet.ibm.com> <20130325171844.GA3637@linux.vnet.ibm.com> Date: Wed, 27 Mar 2013 00:48:20 +0100 Message-ID: Subject: Re: [GIT PULL] nohz: Full dynticks base interface From: Frederic Weisbecker To: paulmck@linux.vnet.ibm.com Cc: Ingo Molnar , LKML , Andrew Morton , Chris Metcalf , Christoph Lameter , Geoff Levand , Gilad Ben Yossef , Hakan Akkan , Kevin Hilman , Li Zhong , Namhyung Kim , Paul Gortmaker , Peter Zijlstra , Steven Rostedt , Thomas Gleixner Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2774 Lines: 61 2013/3/25 Paul E. McKenney : > On Mon, Mar 25, 2013 at 06:12:12PM +0100, Frederic Weisbecker wrote: >> 2013/3/25 Paul E. McKenney : >> > On Sun, Mar 24, 2013 at 03:46:40PM +0100, Frederic Weisbecker wrote: >> >> 2013/3/24 Ingo Molnar : >> >> > >> >> > * Frederic Weisbecker wrote: >> >> > >> >> >> Hi Ingo, >> >> >> >> >> >> This settles the initial ground to start a special full dynticks tree in -tip >> >> >> that we can iterate incrementally to accelerate the development. >> >> >> It is based on tip:sched/core. >> >> >> >> >> >> I tried to rearrange a bit the naming. We are probably not yet done with >> >> >> that but I guess we can fix it along with the rest. >> >> >> >> >> >> Please pull from: >> >> >> >> >> >> git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks.git >> >> >> full-dynticks-for-mingo >> >> >> >> >> >> Changes on these commits since they were part of 3.9-rc1-nohz1: >> >> >> >> >> >> * Force a timekeeping CPU over the full dynticks range >> >> >> * Rename CONFIG_NO_HZ_FULL to CONFIG_NO_HZ_EXTENDED >> >> >> * Following *_nohz_extended_* APIs renames >> >> >> * Handle CPU hotplug for timekeeping >> >> >> * Rename full_nohz= kernel parameter to nohz_extended= >> >> > >> >> > Note that boot parameters suck for pretty much any purpose but quirks - >> >> > please also add a (default off!) Kconfig option to easily enable >> >> > nohz_extended for all CPUs. >> >> > >> >> > That way I will be able to test it automatically via randconfig and such. >> >> >> >> Sure, I'm adding such an option. >> > >> > Hmmm... This would be an option to make all but one CPU an adaptive-ticks >> > CPU, right? If so, this leads to the question of whether I should add a >> > matching no-CBs Kconfig option. My guess is "no", because the existing >> > CONFIG_RCU_NOCB_CPU_ALL should work just fine -- there would be a CPU that >> > was not an adaptive-ticks CPU, but does have its RCU callbacks offloaded. >> > >> > Or am I missing something here? >> >> No that looks right. Now I wonder if I should select >> CONFIG_RCU_NOCB_CPU_ALL at the same time. Probably. > > Sounds like a good initial position to me. If it somehow causes problems, > we can always change it later. Ah "rcu: Provide compile-time control for no-CBs CPUs" is not yet in -tip so I can't do that yet. Ok for now I'm going to add CONFIG_NO_HZ_EXTENDED_ALL and will select the matching RCU config once it's visible upstream. -- 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/