Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932615AbXHPSua (ORCPT ); Thu, 16 Aug 2007 14:50:30 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757337AbXHPSuH (ORCPT ); Thu, 16 Aug 2007 14:50:07 -0400 Received: from netops-testserver-4-out.sgi.com ([192.48.171.29]:60179 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755435AbXHPSuD (ORCPT ); Thu, 16 Aug 2007 14:50:03 -0400 Date: Thu, 16 Aug 2007 11:50:01 -0700 (PDT) From: Christoph Lameter X-X-Sender: clameter@schroedinger.engr.sgi.com To: Paul Mackerras cc: Herbert Xu , Satyam Sharma , "Paul E. McKenney" , Stefan Richter , Chris Snook , Linux Kernel Mailing List , linux-arch@vger.kernel.org, Linus Torvalds , netdev@vger.kernel.org, Andrew Morton , ak@suse.de, heiko.carstens@de.ibm.com, davem@davemloft.net, schwidefsky@de.ibm.com, wensong@linux-vs.org, horms@verge.net.au, wjiang@resilience.com, cfriesen@nortel.com, zlynx@acm.org, rpjday@mindspring.com, jesper.juhl@gmail.com, segher@kernel.crashing.org Subject: Re: [PATCH 0/24] make atomic_read() behave consistently across all architectures In-Reply-To: <18115.59365.268987.406001@cargo.ozlabs.ibm.com> Message-ID: References: <20070816011414.GC9645@linux.vnet.ibm.com> <20070816020851.GA30809@gondor.apana.org.au> <18115.49946.522011.832468@cargo.ozlabs.ibm.com> <20070816033343.GA31844@gondor.apana.org.au> <18115.51472.408193.332905@cargo.ozlabs.ibm.com> <20070816040308.GA32133@gondor.apana.org.au> <18115.54225.644905.463771@cargo.ozlabs.ibm.com> <20070816053741.GA32442@gondor.apana.org.au> <18115.59365.268987.406001@cargo.ozlabs.ibm.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 817 Lines: 21 On Thu, 16 Aug 2007, Paul Mackerras wrote: > Herbert Xu writes: > > > It doesn't matter. The memory pressure flag is an *advisory* > > flag. If we get it wrong the worst that'll happen is that we'd > > waste some time doing work that'll be thrown away. > > Ah, so it's the "racy but I don't care because it's only an > optimization" case. That's fine. Somehow I find it hard to believe > that all the racy uses of atomic_read in the kernel are like that, > though. :) My use of atomic_read in SLUB is like that. Volatile does not magically sync up reads somehow. - 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/