Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030319AbXHPCUw (ORCPT ); Wed, 15 Aug 2007 22:20:52 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S936522AbXHPCUB (ORCPT ); Wed, 15 Aug 2007 22:20:01 -0400 Received: from zcars04f.nortel.com ([47.129.242.57]:63136 "EHLO zcars04f.nortel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S936156AbXHPCT6 (ORCPT ); Wed, 15 Aug 2007 22:19:58 -0400 Message-ID: <46C3B40D.3010909@nortel.com> Date: Wed, 15 Aug 2007 20:18:53 -0600 From: "Chris Friesen" User-Agent: Mozilla Thunderbird 1.0.2-6 (X11/20050513) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Herbert Xu CC: Satyam Sharma , Christoph Lameter , "Paul E. McKenney" , Paul Mackerras , Stefan Richter , Chris Snook , Linux Kernel Mailing List , linux-arch@vger.kernel.org, Linus Torvalds , netdev@vger.kernel.org, Andrew Morton , ak@suse.de, heiko.carstens@de.ibm.com, davem@davemloft.net, schwidefsky@de.ibm.com, wensong@linux-vs.org, horms@verge.net.au, wjiang@resilience.com, zlynx@acm.org, rpjday@mindspring.com, jesper.juhl@gmail.com, segher@kernel.crashing.org Subject: Re: [PATCH 0/24] make atomic_read() behave consistently across all architectures References: <18115.35524.56393.347841@cargo.ozlabs.ibm.com> <20070816003948.GY9645@linux.vnet.ibm.com> <20070816005348.GA9645@linux.vnet.ibm.com> <20070816011414.GC9645@linux.vnet.ibm.com> <20070816020851.GA30809@gondor.apana.org.au> In-Reply-To: <20070816020851.GA30809@gondor.apana.org.au> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 16 Aug 2007 02:18:57.0409 (UTC) FILETIME=[CCF0E710:01C7DFAB] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 957 Lines: 25 Herbert Xu wrote: > But I have to say that I still don't know of a single place > where one would actually use the volatile variant. Given that many of the existing users do currently have "volatile", are you comfortable simply removing that behaviour from them? Are you sure that you will not introduce any issues? Forcing a re-read is only a performance penalty. Removing it can cause behavioural changes. I would be more comfortable making the default match the majority of the current implementations (ie: volatile semantics). Then, if someone cares about performance they can explicitly validate the call path and convert it over to the non-volatile version. Correctness before speed... Chris - 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/