From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Paul E. McKenney" Subject: Re: [PATCH 0/24] make atomic_read() behave consistently across all architectures Date: Wed, 15 Aug 2007 16:51:25 -0700 Message-ID: <20070815235125.GT9645@linux.vnet.ibm.com> References: <46C32618.2080108@redhat.com> <20070815234021.GA28775@gondor.apana.org.au> Reply-To: paulmck@linux.vnet.ibm.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Chris Snook , satyam@infradead.org, clameter@sgi.com, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, torvalds@linux-foundation.org, netdev@vger.kernel.org, akpm@linux-foundation.org, 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 To: Herbert Xu Return-path: Received: from e6.ny.us.ibm.com ([32.97.182.146]:45932 "EHLO e6.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757973AbXHOXv3 (ORCPT ); Wed, 15 Aug 2007 19:51:29 -0400 Content-Disposition: inline In-Reply-To: <20070815234021.GA28775@gondor.apana.org.au> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Thu, Aug 16, 2007 at 07:40:21AM +0800, Herbert Xu wrote: > On Wed, Aug 15, 2007 at 12:13:12PM -0400, Chris Snook wrote: > > > > Part of the motivation here is to fix heisenbugs. If I knew where they > > By the same token we should probably disable optimisations > altogether since that too can create heisenbugs. Precisely the point -- use of volatile (whether in casts or on asms) in these cases are intended to disable those optimizations likely to result in heisenbugs. But they are also intended to leave other valuable optimizations in force. Thanx, Paul