Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752922Ab1BWPCJ (ORCPT ); Wed, 23 Feb 2011 10:02:09 -0500 Received: from blu0-omc1-s32.blu0.hotmail.com ([65.55.116.43]:35710 "EHLO blu0-omc1-s32.blu0.hotmail.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751090Ab1BWPCH (ORCPT ); Wed, 23 Feb 2011 10:02:07 -0500 X-Originating-IP: [174.91.193.52] X-Originating-Email: [pdumas9@sympatico.ca] Message-ID: Date: Wed, 23 Feb 2011 10:02:04 -0500 From: Mathieu Desnoyers To: Steven Rostedt CC: "Paul E. McKenney" , linux-kernel@vger.kernel.org, mingo@elte.hu, laijs@cn.fujitsu.com, dipankar@in.ibm.com, akpm@linux-foundation.org, josh@joshtriplett.org, niv@us.ibm.com, tglx@linutronix.de, peterz@infradead.org, Valdis.Kletnieks@vt.edu, dhowells@redhat.com, eric.dumazet@gmail.com, darren@dvhart.com Subject: Re: [PATCH RFC tip/core/rcu 05/11] rcu: add comment saying why DEBUG_OBJECTS_RCU_HEAD depends on PREEMPT. References: <20110223013917.GA20996@linux.vnet.ibm.com> <1298425183-21265-5-git-send-email-paulmck@linux.vnet.ibm.com> <1298431409.7666.76.camel@gandalf.stny.rr.com> <1298472914.7666.85.camel@gandalf.stny.rr.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Content-Disposition: inline In-Reply-To: <1298472914.7666.85.camel@gandalf.stny.rr.com> X-Editor: vi X-Info: http://krystal.dyndns.org:8080 X-Operating-System: Linux/2.6.27.31-grsec (i686) X-Uptime: 10:01:54 up 322 days, 51 min, 6 users, load average: 1.68, 1.48, 1.48 User-Agent: Mutt/1.5.18 (2008-05-17) X-OriginalArrivalTime: 23 Feb 2011 15:02:06.0710 (UTC) FILETIME=[A3220160:01CBD36A] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1606 Lines: 57 * Steven Rostedt (rostedt@goodmis.org) wrote: > On Wed, 2011-02-23 at 08:59 -0500, Mathieu Desnoyers wrote: > > > #ifdef CONFIG_PREEMPT > > /* > > * Ensure that queued callbacks are all executed. > > * If we detect that we are nested in a RCU read-side > > * critical > > * section, we should simply fail, otherwise we would > > * deadlock. > > */ > > if (rcu_preempt_depth() != 0 || preempt_count() != 0 || > > irqs_disabled()) { > > WARN_ON(1); > > return 0; > > } > > rcu_barrier(); > > rcu_barrier_sched(); > > rcu_barrier_bh(); > > debug_object_init(head, &rcuhead_debug_descr); > > return 1; > > #else > > return 0; > > #endif > > > > instead, no ? > > BTW, if you do end up doing such a thing... > > #ifndef CONFIG_PREEMPT > return 0; > #endif > > before all that would be much cleaner. > > Just make sure any non defined in PREEMPT macros/functions are defined > as nops in !CONFIG_PREEMPT Good point, thanks ! Mathieu > > -- Steve > > -- Mathieu Desnoyers Operating System Efficiency R&D Consultant EfficiOS Inc. http://www.efficios.com -- 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/