Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755958AbZJZTeY (ORCPT ); Mon, 26 Oct 2009 15:34:24 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755044AbZJZTeY (ORCPT ); Mon, 26 Oct 2009 15:34:24 -0400 Received: from einhorn.in-berlin.de ([192.109.42.8]:48705 "EHLO einhorn.in-berlin.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751246AbZJZTeX (ORCPT ); Mon, 26 Oct 2009 15:34:23 -0400 X-Envelope-From: stefanr@s5r6.in-berlin.de Message-ID: <4AE5F9B9.2010707@s5r6.in-berlin.de> Date: Mon, 26 Oct 2009 20:34:17 +0100 From: Stefan Richter User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.8.1.23) Gecko/20091025 SeaMonkey/1.1.18 MIME-Version: 1.0 To: Noah Watkins CC: "Leonidas ." , Chris Friesen , linux-kernel Subject: Re: Difference between atomic operations and memory barriers References: <7ADB5FD7-9C97-4987-BC20-997258B25FD2@noahdesu.com> <4AE5F04E.3050908@nortel.com> In-Reply-To: X-Enigmail-Version: 0.96.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 799 Lines: 23 Noah Watkins wrote: >> So we can safely assume that pointer assignment will be done in an >> atomic manner? > > See the the comment above rcu_assign_pointer in > include/linux/rcupdate.h This comment only talks about ordering, not about atomicity. Again, AFAIR the ISO C spec should explain what is going to be guaranteed atomic and what might not be atomic. rcu_assign_pointer() itself does rely on atomicity of pointer assignments though, like lots of code elsewhere in the kernel. -- Stefan Richter -=====-==--= =-=- ==-=- http://arcgraph.de/sr/ -- 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/