Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761296AbYGJSPB (ORCPT ); Thu, 10 Jul 2008 14:15:01 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1760263AbYGJSOw (ORCPT ); Thu, 10 Jul 2008 14:14:52 -0400 Received: from terminus.zytor.com ([198.137.202.10]:35007 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760219AbYGJSOw (ORCPT ); Thu, 10 Jul 2008 14:14:52 -0400 Message-ID: <48765006.4020505@zytor.com> Date: Thu, 10 Jul 2008 14:08:06 -0400 From: "H. Peter Anvin" User-Agent: Thunderbird 2.0.0.14 (X11/20080501) MIME-Version: 1.0 To: "Eric W. Biederman" CC: Jeremy Fitzhardinge , Arjan van de Ven , Ingo Molnar , Mike Travis , Andrew Morton , Christoph Lameter , Jack Steiner , linux-kernel@vger.kernel.org Subject: Re: [RFC 00/15] x86_64: Optimize percpu accesses References: <20080709165129.292635000@polaris-admin.engr.sgi.com> <20080709200757.GD14009@elte.hu> <48751B57.8030605@goop.org> <20080709133958.612635f0@infradead.org> <4875231F.1020506@zytor.com> <487524A0.6020304@goop.org> <487529AE.3060505@zytor.com> <48753A71.2030006@zytor.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 911 Lines: 23 Eric W. Biederman wrote: > > Another alternative that almost fares better then a segment with > a base of zero is a base of -32K or so. Only trouble that would get us > manually managing the per cpu area size again. > Yes, an extra link pass would be better than that. I have tried, and none of the clever things I tried actually works, since GNU ld has pretty much no way to get it to reveal its information ahead of time. However, I want to explore the details of the supposed toolchain issue; it might be just a simple tweak to the way things are done now to fix it. Clearly, given the stack protector ABI, we want %gs:40 to be usable and free. -hpa -- 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/