Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761508AbYCCWYl (ORCPT ); Mon, 3 Mar 2008 17:24:41 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754293AbYCCWY0 (ORCPT ); Mon, 3 Mar 2008 17:24:26 -0500 Received: from smtp1.linux-foundation.org ([140.211.169.13]:44263 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761266AbYCCWYY (ORCPT ); Mon, 3 Mar 2008 17:24:24 -0500 Date: Mon, 3 Mar 2008 14:23:40 -0800 (PST) From: Linus Torvalds To: "Rafael J. Wysocki" cc: Pavel Machek , Alan Cox , Alan Stern , Andrew Morton , Zdenek Kabelac , davem@davemloft.net, Pierre Ossman , Kernel development list , pm list , "Paul E. McKenney" Subject: Re: [patch] Re: using long instead of atomic_t when only set/read is required In-Reply-To: <200803032127.30761.rjw@sisk.pl> Message-ID: References: <20080225090316.GA420@elf.ucw.cz> <20080303154831.22a4eb14@core> <20080303172410.GA13869@elf.ucw.cz> <200803032127.30761.rjw@sisk.pl> User-Agent: Alpine 1.00 (LFD 882 2007-12-20) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 764 Lines: 24 On Mon, 3 Mar 2008, Rafael J. Wysocki wrote: > > Well something like this could happen, in theory, on a "32-bit" architecture > with a 16-bit bus. No it couldn't. That would only be true if there is no cache, and no cache coherency. Basically, Linux requires a cache-coherent architecture to work in SMP. Anything else is insane (except as a cluster). So there is no way we can see partial updates, except with terminally broken hardware that we would never support anyway for tons of other reasons. Linus -- 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/