From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030768AbWKORwb (ORCPT ); Wed, 15 Nov 2006 12:52:31 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030766AbWKORwb (ORCPT ); Wed, 15 Nov 2006 12:52:31 -0500 Received: from gw.goop.org ([64.81.55.164]:37260 "EHLO mail.goop.org") by vger.kernel.org with ESMTP id S1030768AbWKORwa (ORCPT ); Wed, 15 Nov 2006 12:52:30 -0500 Message-ID: <455B53DD.1030305@goop.org> Date: Wed, 15 Nov 2006 09:52:29 -0800 From: Jeremy Fitzhardinge User-Agent: Thunderbird 1.5.0.8 (X11/20061107) MIME-Version: 1.0 To: Eric Dumazet CC: akpm@osdl.org, Arjan van de Ven , ak@suse.de, mingo@elte.hu, linux-kernel@vger.kernel.org Subject: Re: [PATCH] i386-pda UP optimization References: <1158046540.2992.5.camel@laptopd505.fenrus.org> <4506665D.2090001@goop.org> <1158047806.2992.7.camel@laptopd505.fenrus.org> <200611151227.04777.dada1@cosmosbay.com> In-Reply-To: <200611151227.04777.dada1@cosmosbay.com> Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Eric Dumazet wrote: > I wish Jeremy give us patches for UP machines so that %gs can be let untouched > in entry.S (syscall entry/exit). A lot of ia32 machines are still using one > CPU. > Unfortunately that would add cruft in a number of places. At the moment, context switch, ptrace and vm86 all assume entry.S has saved %gs into pt_regs, so they can treat it like any other register. If this were conditional, it would require multiple places to add #ifndef CONFIG_SMP code, which is not something I'd like to do without a good reason. J