Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965113AbWEKBEl (ORCPT ); Wed, 10 May 2006 21:04:41 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965112AbWEKBEk (ORCPT ); Wed, 10 May 2006 21:04:40 -0400 Received: from CPE-144-136-172-108.sa.bigpond.net.au ([144.136.172.108]:7984 "EHLO grove.modra.org") by vger.kernel.org with ESMTP id S965101AbWEKBEk (ORCPT ); Wed, 10 May 2006 21:04:40 -0400 Date: Thu, 11 May 2006 10:34:38 +0930 From: Alan Modra To: Paul Mackerras Cc: "David S. Miller" , linux-arch@vger.kernel.org, linuxppc-dev@ozlabs.org, linux-kernel@vger.kernel.org, rth@twiddle.net Subject: Re: [RFC/PATCH] Make powerpc64 use __thread for per-cpu variables Message-ID: <20060511010438.GE24458@bubble.grove.modra.org> References: <17505.26159.807484.477212@cargo.ozlabs.ibm.com> <20060510154702.GA28938@twiddle.net> <20060510.124003.04457042.davem@davemloft.net> <17506.21908.857189.645889@cargo.ozlabs.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <17506.21908.857189.645889@cargo.ozlabs.ibm.com> User-Agent: Mutt/1.4i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 762 Lines: 21 On Thu, May 11, 2006 at 07:05:24AM +1000, Paul Mackerras wrote: > No, Richard has a point, it's not the value that is the concern, it's > the address, which gcc could assume is still valid after a barrier. > Drat. That may never happen, at least with a compiler that knows how to optimise away the addi. You're using -mtls-size=16 so all your accesses should look like lwz rn,per_cpu_var@tprel(13) gcc shouldn't think there is any reason to cache the address. -- Alan Modra IBM OzLabs - Linux Technology Centre - 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/