Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760067AbZARFaq (ORCPT ); Sun, 18 Jan 2009 00:30:46 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752084AbZARFag (ORCPT ); Sun, 18 Jan 2009 00:30:36 -0500 Received: from hera.kernel.org ([140.211.167.34]:33793 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752056AbZARFae (ORCPT ); Sun, 18 Jan 2009 00:30:34 -0500 Message-ID: <4972BE69.2000609@kernel.org> Date: Sun, 18 Jan 2009 14:30:17 +0900 From: Tejun Heo User-Agent: Thunderbird 2.0.0.19 (X11/20081227) MIME-Version: 1.0 To: Brian Gerst CC: Ingo Molnar , linux-kernel@vger.kernel.org Subject: Re: [PATCH 13/17] x86-64: Remove pda_init() References: <73c1f2160901160610l57e31a64j56fe9544bd2fd309@mail.gmail.com> <1232115396-26367-6-git-send-email-brgerst@gmail.com> <1232115396-26367-7-git-send-email-brgerst@gmail.com> <1232115396-26367-8-git-send-email-brgerst@gmail.com> <1232115396-26367-9-git-send-email-brgerst@gmail.com> <1232115396-26367-10-git-send-email-brgerst@gmail.com> <1232115396-26367-11-git-send-email-brgerst@gmail.com> <1232115396-26367-12-git-send-email-brgerst@gmail.com> <1232115396-26367-13-git-send-email-brgerst@gmail.com> <4972B0E3.8060200@kernel.org> <73c1f2160901172120i174a8933qfdb51e654f13c785@mail.gmail.com> In-Reply-To: <73c1f2160901172120i174a8933qfdb51e654f13c785@mail.gmail.com> X-Enigmail-Version: 0.95.7 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.0 (hera.kernel.org [127.0.0.1]); Sun, 18 Jan 2009 05:30:22 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1561 Lines: 45 Brian Gerst wrote: > On Sat, Jan 17, 2009 at 11:32 PM, Tejun Heo wrote: >> Hello, >> >> Brian Gerst wrote: >>> -void __cpuinit pda_init(int cpu) >>> -{ >>> - struct x8664_pda *pda = cpu_pda(cpu); >>> - >>> - /* Setup up data that may be needed in __get_free_pages early */ >>> - loadsegment(fs, 0); >>> - loadsegment(gs, 0); >>> - >>> - load_pda_offset(cpu); >>> -} >> Simply removing these should work fine as they're also initialized in >> other places earlier but I think they still need to be in cpu_init() >> because... >> >> /* >> * cpu_init() initializes state that is per-CPU. Some data is already >> * initialized (naturally) in the bootstrap process, such as the GDT >> * and IDT. We reload them nevertheless, this function acts as a >> ^^^^^^^^^^^^^^^^^^^^^^^^^^^ >> * 'CPU state barrier', nothing should get across. >> * A lot of state is already set up in PDA init for 64 bit >> */ > > That comment seems like overkill. It may have been relevant in an > earlier time, but I don't think we need to be so strict now, > especially for things we know are set properly in head_xx.S. That may be so, but wouldn't such change deserve a separate patch with accompanying update in the comment? It's not simple move from A to B change. Thanks. -- tejun -- 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/