Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751657AbWIZAZz (ORCPT ); Mon, 25 Sep 2006 20:25:55 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751658AbWIZAZz (ORCPT ); Mon, 25 Sep 2006 20:25:55 -0400 Received: from tomts40.bellnexxia.net ([209.226.175.97]:37089 "EHLO tomts40-srv.bellnexxia.net") by vger.kernel.org with ESMTP id S1751656AbWIZAZy (ORCPT ); Mon, 25 Sep 2006 20:25:54 -0400 Date: Mon, 25 Sep 2006 20:25:51 -0400 From: Mathieu Desnoyers To: Jeremy Fitzhardinge Cc: Martin Bligh , "Frank Ch. Eigler" , Masami Hiramatsu , prasanna@in.ibm.com, Andrew Morton , Ingo Molnar , Paul Mundt , linux-kernel , Jes Sorensen , Tom Zanussi , Richard J Moore , Michel Dagenais , Christoph Hellwig , Greg Kroah-Hartman , Thomas Gleixner , William Cohen , ltt-dev@shafik.org, systemtap@sources.redhat.com, Alan Cox , Karim Yaghmour , Pavel Machek , Joe Perches , "Randy.Dunlap" , "Jose R. Santos" Subject: Re: [PATCH] Linux Kernel Markers 0.13 for 2.6.17 Message-ID: <20060926002551.GA18276@Krystal> References: <20060925233349.GA2352@Krystal> <20060925235617.GA3147@Krystal> <45187146.8040302@goop.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline In-Reply-To: <45187146.8040302@goop.org> X-Editor: vi X-Info: http://krystal.dyndns.org:8080 X-Operating-System: Linux/2.4.32-grsec (i686) X-Uptime: 20:22:28 up 33 days, 21:31, 3 users, load average: 0.05, 0.21, 0.24 User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1498 Lines: 45 * Jeremy Fitzhardinge (jeremy@goop.org) wrote: > Mathieu Desnoyers wrote: > >Just as a precision : > > > >The following sequence (please refer to the code below for local symbols > >1 and 2) : > > > >1: > >preempt_disable() > >call (*__mark_call_##name)(format, ## args); > >preempt_enable_no_resched() > >2: > > > >is insured because : > > > >1 is part of an inline assembly with rw dependency on __marker_sequencer > >the call is surrounded by memory barriers. > >2 is part of an inline assembly with rw dependency on __marker_sequencer > > > > What do you mean the call is surrounded by memory barriers? Do you mean > a call has an implicit barrier, or something else? > Yes, preempt_disable() has a barrier(), on gcc : __asm__ __volatile__("": : :"memory"). > Either way, this doesn't prevent some otherwise unrelated > non-memory-using code from being scheduled in there, which would not be > executed. The gcc manual really strongly discourages jumping between > inline asms, because they have basically unpredictable results. > Ok, I will do the call in assembly then. Mathieu OpenPGP public key: http://krystal.dyndns.org:8080/key/compudj.gpg 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/