Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934336AbXHGPvU (ORCPT ); Tue, 7 Aug 2007 11:51:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1761617AbXHGPvK (ORCPT ); Tue, 7 Aug 2007 11:51:10 -0400 Received: from zrtps0kp.nortel.com ([47.140.192.56]:40268 "EHLO zrtps0kp.nortel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755864AbXHGPvJ (ORCPT ); Tue, 7 Aug 2007 11:51:09 -0400 Message-ID: <46B894E4.4010501@nortel.com> Date: Tue, 07 Aug 2007 09:51:00 -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: Chris Snook CC: Jerry Jiang , "Robert P. J. Day" , Linux Kernel Mailing List Subject: Re: why are some atomic_t's not volatile, while most are? References: <20070806123551.a6c3c154.wjiang@resilience.com> <46B72C58.5030502@redhat.com> In-Reply-To: <46B72C58.5030502@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 07 Aug 2007 15:51:03.0410 (UTC) FILETIME=[C22EDD20:01C7D90A] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 724 Lines: 19 Chris Snook wrote: > If your architecture doesn't support SMP, the volatile keyword doesn't > do anything except add a useless memory fetch. I was under the impression that there were other cases as well (interrupt handlers, for instance) where the value could be modified "behind the back" of the current code. It seems like this would fall more into the case of the arch providing guarantees when using locked/atomic access rather than anything SMP-related, no?. 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/