Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757526AbYGJQcQ (ORCPT ); Thu, 10 Jul 2008 12:32:16 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751251AbYGJQcE (ORCPT ); Thu, 10 Jul 2008 12:32:04 -0400 Received: from terminus.zytor.com ([198.137.202.10]:44668 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750833AbYGJQcC (ORCPT ); Thu, 10 Jul 2008 12:32:02 -0400 Message-ID: <487637DE.1050706@zytor.com> Date: Thu, 10 Jul 2008 12:25:02 -0400 From: "H. Peter Anvin" User-Agent: Thunderbird 2.0.0.14 (X11/20080501) MIME-Version: 1.0 To: Mike Travis CC: "Eric W. Biederman" , Jeremy Fitzhardinge , Arjan van de Ven , Ingo Molnar , Andrew Morton , Christoph Lameter , Jack Steiner , linux-kernel@vger.kernel.org, Rusty Russell 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> <48763732.7020805@sgi.com> In-Reply-To: <48763732.7020805@sgi.com> 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: 953 Lines: 24 Mike Travis wrote: > 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. > > One thing to remember is the eventual goal is implementing the cpu_alloc > functions which I think we've agreed has to be "growable". This means that > the addresses will need to be virtual to allow the same offsets for all cpus. > The patchset I have uses 2Mb pages. This "little" twist might figure into the > implementation issues that are being discussed. > No, since the *addresses* can be arbitrary. The current issue is about *offsets.* -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/