Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753953Ab0AURHW (ORCPT ); Thu, 21 Jan 2010 12:07:22 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753728Ab0AURHU (ORCPT ); Thu, 21 Jan 2010 12:07:20 -0500 Received: from tomts10-srv.bellnexxia.net ([209.226.175.54]:41148 "EHLO tomts10-srv.bellnexxia.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753657Ab0AURHS (ORCPT ); Thu, 21 Jan 2010 12:07:18 -0500 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: ArEEAFcXWEuuWOiG/2dsb2JhbACBRthihDwE Date: Thu, 21 Jan 2010 12:02:15 -0500 From: Mathieu Desnoyers To: Steven Rostedt Cc: Peter Zijlstra , linux-kernel@vger.kernel.org, "Paul E. McKenney" , Oleg Nesterov , Ingo Molnar , akpm@linux-foundation.org, josh@joshtriplett.org, tglx@linutronix.de, Valdis.Kletnieks@vt.edu, dhowells@redhat.com, laijs@cn.fujitsu.com, dipankar@in.ibm.com Subject: Re: [RFC PATCH] introduce sys_membarrier(): process-wide memory barrier (v5) Message-ID: <20100121170215.GC15761@Krystal> References: <20100114183739.GA18435@Krystal> <1263495132.28171.3861.camel@gandalf.stny.rr.com> <20100114193355.GA23436@Krystal> <1263926259.4283.757.camel@laptop> <1263928006.4283.762.camel@laptop> <1264073212.4283.1158.camel@laptop> <20100121160729.GB12842@Krystal> <1264090331.31321.212.camel@gandalf.stny.rr.com> <20100121162249.GA15761@Krystal> <1264091529.31321.223.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: <1264091529.31321.223.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: 12:02:08 up 36 days, 1:20, 5 users, load average: 0.05, 0.13, 0.15 User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1059 Lines: 36 * Steven Rostedt (rostedt@goodmis.org) wrote: > On Thu, 2010-01-21 at 11:22 -0500, Mathieu Desnoyers wrote: > > * Steven Rostedt (rostedt@goodmis.org) wrote: > > > > You may also need spin_lock_irqsave, et al. variants too. > > > > Yep, or we simply use the local_irq_save/restore separately. That could > > be a good idea given that only few specialized sites are affected. > > If it gets used more often, then we need to consider RT. RT modifies > spin_lock_irqsave into a standard mutex that does not disable > interrupts. But if something does: > > local_irq_save(flags); > spin_lock_mb(&lock); > [...] > > Then it will break RT (if lock is to be converted). Good point ! Mathieu > > -- Steve > > -- Mathieu Desnoyers OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68 -- 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/