Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753321AbZJ1KAK (ORCPT ); Wed, 28 Oct 2009 06:00:10 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752532AbZJ1KAK (ORCPT ); Wed, 28 Oct 2009 06:00:10 -0400 Received: from mail-bw0-f227.google.com ([209.85.218.227]:55703 "EHLO mail-bw0-f227.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751247AbZJ1KAI (ORCPT ); Wed, 28 Oct 2009 06:00:08 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=sender:message-id:date:from:user-agent:mime-version:to:cc:subject :references:in-reply-to:content-type:content-transfer-encoding; b=thCz3EuUxP/fQcKuchgdKS+RBRVmC6TPTfHBR0WeNJVj/5u4GRYO/hyAB+M6bjH2TS qwPMhfg2Xx4cz3oduN5AWwrUmsZKhrRwnr9dLxoJNp7hoBIt1/GQR02rd1NMzMhMQvrN OJlXTyoFic6VJwe3KkNdDe1obHWuo1ZPc/klU= Message-ID: <4AE81625.5000500@panasas.com> Date: Wed, 28 Oct 2009 12:00:05 +0200 From: Boaz Harrosh User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.4pre) Gecko/20090924 Remi/fc10 Thunderbird/3.0b4 MIME-Version: 1.0 To: Valdis.Kletnieks@vt.edu CC: "Leonidas ." , Chris Friesen , Noah Watkins , linux-kernel Subject: Re: Difference between atomic operations and memory barriers References: <7ADB5FD7-9C97-4987-BC20-997258B25FD2@noahdesu.com> <4AE5F04E.3050908@nortel.com> <45208.1256644303@turing-police.cc.vt.edu> In-Reply-To: <45208.1256644303@turing-police.cc.vt.edu> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1171 Lines: 28 On 10/27/2009 01:51 PM, Valdis.Kletnieks@vt.edu wrote: > On Tue, 27 Oct 2009 00:30:45 +0530, "Leonidas ." said: > >> So we can safely assume that pointer assignment will be done in an >> atomic manner? > > Has anybody ever actually made a *production* CPU that had non-atomic > pointer assignments? And how long before the crazed programmers lynched > and burned the offending CPU designer at the stake? ;) > > Non-atomic pointer assignments are the CPU design equivalent of Vogon poetry. > Just Say No. With a shotgun if needed. What don't you know? the CPU that started it all was like that, the x86 16-bit "large" and "huge" model had a double register seg:offset set, also in-memory was double-ints(2*16) even the i386 was running 16 bit modes for a long time. Kernel still have 16-bit dosemu mode supported until today, no? About the shotguns lynching and burning I'm not sure, but Intel survived just fine. Boaz -- 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/