From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751279AbaLRPll (ORCPT ); Thu, 18 Dec 2014 10:41:41 -0500 Received: from mga09.intel.com ([134.134.136.24]:57288 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751057AbaLRPlk (ORCPT ); Thu, 18 Dec 2014 10:41:40 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.07,601,1413270000"; d="scan'208";a="626031232" Message-ID: <5492F474.5090606@intel.com> Date: Thu, 18 Dec 2014 07:36:20 -0800 From: Dave Hansen User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.3.0 MIME-Version: 1.0 To: Christoph Lameter CC: Fenghua Yu , Thomas Gleixner , "H. Peter Anvin" , Ingo Molnar , Glenn Williamson , linux-kernel , x86 Subject: Re: [PATCH v2] X86-32: Allocate 256 bytes for pgd in PAE paging References: <1418852859-18852-1-git-send-email-fenghua.yu@intel.com> <54921EF2.9070004@intel.com> In-Reply-To: Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/18/2014 06:52 AM, Christoph Lameter wrote: > On Wed, 17 Dec 2014, Dave Hansen wrote: >> > IOW, do *ALL* of the sl*b allocators in all of their forms with all of >> > their debugging options guarantee 32-byte alignment when allocating >> > 256-byte objects? > No. For that the arch has to set a macro call ARCH_KMALLOC_MINALIGN or > ARCH_DMA_MINALIGN. Default alignment is to a word boundary. OK, sounds like this is going to need its own slab. It will make the patch a bit bigger but shouldn't be all that much more complicated.