Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751210AbVJOTaY (ORCPT ); Sat, 15 Oct 2005 15:30:24 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751211AbVJOTaY (ORCPT ); Sat, 15 Oct 2005 15:30:24 -0400 Received: from dsl027-180-168.sfo1.dsl.speakeasy.net ([216.27.180.168]:49552 "EHLO sunset.davemloft.net") by vger.kernel.org with ESMTP id S1751210AbVJOTaX (ORCPT ); Sat, 15 Oct 2005 15:30:23 -0400 Date: Sat, 15 Oct 2005 12:29:38 -0700 (PDT) Message-Id: <20051015.122938.14078749.davem@davemloft.net> To: torvalds@osdl.org Cc: herbert@gondor.apana.org.au, benh@kernel.crashing.org, hugh@veritas.com, paulus@samba.org, anton@samba.org, nickpiggin@yahoo.com.au, akpm@osdl.org, andrea@suse.de, linux-kernel@vger.kernel.org Subject: Re: Possible memory ordering bug in page reclaim? From: "David S. Miller" In-Reply-To: References: X-Mailer: Mew version 4.2.53 on Emacs 21.4 / Mule 5.0 (SAKAKI) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 687 Lines: 18 From: Linus Torvalds Date: Sat, 15 Oct 2005 09:57:47 -0700 (PDT) > On Sat, 15 Oct 2005, Herbert Xu wrote: > > > > Yes atomic_add_negative should always be a barrier. > > I disagree. That would be very expensive on anything but x86, where it > just happens to be true for other reasons. Atomics do _not_ implement > barriers. When they return values, they are defined to be barriers. It's even on the documentation :-) - 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/