From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from fallback-mx.in-berlin.de ([192.109.42.17]:53472 "EHLO hirscho.in-berlin.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753237AbXHOQMs (ORCPT ); Wed, 15 Aug 2007 12:12:48 -0400 Received: from einhorn.in-berlin.de (einhorn.in-berlin.de [192.109.42.8]) by fallback-mx.in-berlin.de (8.13.6/8.13.6/Debian-1) with ESMTP id l7FGCltS024819 for ; Wed, 15 Aug 2007 18:12:47 +0200 Message-ID: <46C3253F.5090707@s5r6.in-berlin.de> Date: Wed, 15 Aug 2007 18:09:35 +0200 From: Stefan Richter MIME-Version: 1.0 Subject: Re: [PATCH 0/24] make atomic_read() behave consistently across all architectures References: <46C2350A.1010807@redhat.com> <20070815081841.GA16551@osiris.boeblingen.de.ibm.com> <46C30540.2070603@s5r6.in-berlin.de> <20070815145207.GA23106@gondor.apana.org.au> In-Reply-To: <20070815145207.GA23106@gondor.apana.org.au> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-arch-owner@vger.kernel.org To: Herbert Xu Cc: Satyam Sharma , Heiko Carstens , Chris Snook , clameter@sgi.com, Linux Kernel Mailing List , linux-arch@vger.kernel.org, Linus Torvalds , netdev@vger.kernel.org, Andrew Morton , ak@suse.de, 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 List-ID: Herbert Xu wrote: > On Wed, Aug 15, 2007 at 08:05:38PM +0530, Satyam Sharma wrote: >>> I don't know if this here is affected: [...something like] b = atomic_read(a); for (i = 0; i < 4; i++) { msleep_interruptible(63); c = atomic_read(a); if (c != b) { b = c; i = 0; } } > Nope, we're calling schedule which is a rather heavy-weight > barrier. How does the compiler know that msleep() has got barrier()s? -- Stefan Richter -=====-=-=== =--- -==== http://arcgraph.de/sr/