From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753190Ab1G2XSm (ORCPT ); Fri, 29 Jul 2011 19:18:42 -0400 Received: from mga03.intel.com ([143.182.124.21]:38555 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752808Ab1G2XSl (ORCPT ); Fri, 29 Jul 2011 19:18:41 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.67,289,1309762800"; d="scan'208";a="33176085" From: Andi Kleen To: Christoph Lameter Cc: Pekka Enberg , torvalds@linux-foundation.org, akpm@linux-foundation.org, rientjes@google.com, hughd@google.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [GIT PULL] Lockless SLUB slowpaths for v3.1-rc1 References: Date: Fri, 29 Jul 2011 16:18:37 -0700 In-Reply-To: (Christoph Lameter's message of "Fri, 29 Jul 2011 10:04:36 -0500 (CDT)") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Christoph Lameter writes: > On Fri, 29 Jul 2011, Pekka Enberg wrote: > >> We haven't come up with a solution to keep struct page size the same but I >> think it's a reasonable trade-off. > > The change requires the page struct to be aligned to a double word > boundary. Why is that? > There is actually no variable added to the page struct. Its just > the alignment requirement that causes padding to be added after each page > struct. These days with everyone using cgroups (and likely mcgroups too) you could probably put the cgroups page pointer back there. It's currently external. -Andi -- ak@linux.intel.com -- Speaking for myself only