Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751245AbVJOWSP (ORCPT ); Sat, 15 Oct 2005 18:18:15 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751246AbVJOWSO (ORCPT ); Sat, 15 Oct 2005 18:18:14 -0400 Received: from gate.crashing.org ([63.228.1.57]:52921 "EHLO gate.crashing.org") by vger.kernel.org with ESMTP id S1751245AbVJOWSN (ORCPT ); Sat, 15 Oct 2005 18:18:13 -0400 Subject: Re: Possible memory ordering bug in page reclaim? From: Benjamin Herrenschmidt To: "David S. Miller" Cc: torvalds@osdl.org, herbert@gondor.apana.org.au, hugh@veritas.com, paulus@samba.org, anton@samba.org, nickpiggin@yahoo.com.au, akpm@osdl.org, andrea@suse.de, linux-kernel@vger.kernel.org In-Reply-To: <20051015.122938.14078749.davem@davemloft.net> References: <20051015.122938.14078749.davem@davemloft.net> Content-Type: text/plain Date: Sun, 16 Oct 2005 08:17:00 +1000 Message-Id: <1129414620.7620.14.camel@gaston> Mime-Version: 1.0 X-Mailer: Evolution 2.2.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 850 Lines: 26 On Sat, 2005-10-15 at 12:29 -0700, David S. Miller wrote: > 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 :-) Ahhh, good to know :) /me should read the documentation sometimes.... Ben. - 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/