From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757838AbYDPXdn (ORCPT ); Wed, 16 Apr 2008 19:33:43 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752552AbYDPXdd (ORCPT ); Wed, 16 Apr 2008 19:33:33 -0400 Received: from tomts43-srv.bellnexxia.net ([209.226.175.110]:33104 "EHLO tomts43-srv.bellnexxia.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750840AbYDPXdd (ORCPT ); Wed, 16 Apr 2008 19:33:33 -0400 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: Aq8EABIpBkhMROPA/2dsb2JhbACBYKwq Date: Wed, 16 Apr 2008 19:33:31 -0400 From: Mathieu Desnoyers To: Paul Mackerras Cc: Ingo Molnar , linux-kernel@vger.kernel.org, Rusty Russell , Christoph Hellwig Subject: Re: [RFC patch 23/27] Immediate Values - Powerpc Optimization NMI MCE support Message-ID: <20080416233331.GA9225@Krystal> References: <20080416213426.298498397@polymtl.ca> <20080416213556.704299869@polymtl.ca> <18438.34621.508450.720068@cargo.ozlabs.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline In-Reply-To: <18438.34621.508450.720068@cargo.ozlabs.ibm.com> X-Editor: vi X-Info: http://krystal.dyndns.org:8080 X-Operating-System: Linux/2.6.21.3-grsec (i686) X-Uptime: 19:31:36 up 47 days, 19:42, 5 users, load average: 0.05, 0.09, 0.13 User-Agent: Mutt/1.5.16 (2007-06-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Paul Mackerras (paulus@samba.org) wrote: > Mathieu Desnoyers writes: > > > Use an atomic update for immediate values. > > What is meant by an "atomic" update in this context? AFAICS you are > using memcpy, which is not in any way guaranteed to be atomic. > > Paul. I expect memcpy to perform the copy in one memory access, given I put a .align 2 before the 2 bytes instruction. It makes sure the instruction modified fits in a single, aligned, memory write. Or maybe am I expecting too much from memcpy ? Mathieu -- Mathieu Desnoyers Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68