From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754179AbYL0KgQ (ORCPT ); Sat, 27 Dec 2008 05:36:16 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752689AbYL0Kf7 (ORCPT ); Sat, 27 Dec 2008 05:35:59 -0500 Received: from mx2.mail.elte.hu ([157.181.151.9]:36446 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752574AbYL0Kf7 (ORCPT ); Sat, 27 Dec 2008 05:35:59 -0500 Date: Sat, 27 Dec 2008 11:35:01 +0100 From: Ingo Molnar To: "Paul E. McKenney" Cc: linux-kernel@vger.kernel.org, tglx@linutronix.de, akpm@linux-foundation.org, ralf@linux-mips.org, kernel@wantstofly.org, hskinnemoen@atmel.com, cooloney@kernel.org, tony.luck@intel.com, geert@linux-m68k.org, zippel@linux-m68k.org, jwboyer@linux.vnet.ibm.com, mporter@kernel.crashing.org, grant.likely@secretlab.ca, paulus@samba.org, benh@kernel.crashing.org, dhowells@redhat.com, yasutake.koichi@jp.panasonic.com, lethal@linux-sh.org, hpa@zytor.com Subject: Re: [PATCH, -tip] Make hierarchical RCU be the default Message-ID: <20081227103501.GG14639@elte.hu> References: <1229991147545-git-send-email-paulmck@linux.vnet.ibm.com> <12299911471985-git-send-email-paulmck@linux.vnet.ibm.com> <20081223142542.GC29151@elte.hu> <20081223215948.GA16137@linux.vnet.ibm.com> <20081223220345.GA16472@linux.vnet.ibm.com> <20081223220648.GB16472@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20081223220648.GB16472@linux.vnet.ibm.com> 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 * Paul E. McKenney wrote: > --- a/include/linux/hardirq.h > +++ b/include/linux/hardirq.h > @@ -118,7 +118,7 @@ static inline void account_system_vtime(struct task_struct *tsk) > } > #endif > > -#if defined(CONFIG_NO_HZ) && !defined(CONFIG_CLASSIC_RCU) > +#if defined(CONFIG_NO_HZ) && !defined(CONFIG_FLAT_RCU) this can be done in an even lazier fashion, via a ~5 lines patch. Just add FLAT_RCU as the new kconfig method, and make CONFIG_CLASSIC_RCU mirror it via something like: config CLASSIC_RCU bool default FLAT_RCU that makes your patch only affect the Kconfig file - and makes it easily revertable, etc. Ingo