Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751665AbZGaXbF (ORCPT ); Fri, 31 Jul 2009 19:31:05 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751246AbZGaXbE (ORCPT ); Fri, 31 Jul 2009 19:31:04 -0400 Received: from are.twiddle.net ([75.149.56.221]:47994 "EHLO are.twiddle.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750865AbZGaXbE (ORCPT ); Fri, 31 Jul 2009 19:31:04 -0400 Message-ID: <4A737EB1.1000602@twiddle.net> Date: Fri, 31 Jul 2009 16:30:57 -0700 From: Richard Henderson User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1b3pre) Gecko/20090513 Fedora/3.0-2.3.beta2.fc11 Thunderbird/3.0b2 MIME-Version: 1.0 To: Tim Abbott CC: Linux Kernel Mailing List , Sam Ravnborg , Anders Kaseorg , Nelson Elhage , linux-alpha@vger.kernel.org Subject: Re: [PATCH 1/2] alpha: use .data.init_task instead of .data.init_thread. References: <1249073786-29788-1-git-send-email-tabbott@ksplice.com> <4A7360C3.2060507@twiddle.net> 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: 1174 Lines: 34 On 07/31/2009 03:02 PM, Tim Abbott wrote: > The INIT_TASK_DATA(THREAD_SIZE) macro call aligns to THREAD_SIZE (= > 2*PAGE_SIZE). So I'm not removing the 2 page alignment; I'm just moving > it along with the code that needs to be aligned. Sure. > > This change: > > - . = ALIGN(2 * PAGE_SIZE); > + . = ALIGN(PAGE_SIZE); > __init_end = .; > > removes the now-unnecessary (2 * PAGE_SIZE) alignment for __init_end > caused by moving .data.init_task (it should have been in the first patch). While it's technically unnecessary, it's also very much desired. Think about it. Suppose we have 9 pages of init, followed by the two-page-aligned INIT_TASK_DATA. So we get a page worth of padding added. It's better to have the two-page-alignment within the init section so as to get 10 pages of init followed by no padding. In this way the page of padding gets freed with the rest of init. Are you following me at all here? r~ -- 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/