From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752919AbaAPARF (ORCPT ); Wed, 15 Jan 2014 19:17:05 -0500 Received: from mta-out.inet.fi ([195.156.147.13]:35077 "EHLO jenni2.inet.fi" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752135AbaAPARD (ORCPT ); Wed, 15 Jan 2014 19:17:03 -0500 Date: Thu, 16 Jan 2014 02:16:54 +0200 From: "Kirill A. Shutemov" To: Dave Hansen Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, penberg@kernel.org, cl@linux-foundation.org Subject: Re: [RFC][PATCH 3/9] mm: page->pfmemalloc only used by slab/skb Message-ID: <20140116001654.GB8456@node.dhcp.inet.fi> References: <20140114180042.C1C33F78@viggo.jf.intel.com> <20140114180051.0181E467@viggo.jf.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140114180051.0181E467@viggo.jf.intel.com> User-Agent: Mutt/1.5.22.1-rc1 (2013-10-16) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jan 14, 2014 at 10:00:51AM -0800, Dave Hansen wrote: > > From: Dave Hansen > > page->pfmemalloc does not deserve a spot in 'struct page'. It is > only used transiently _just_ after a page leaves the buddy > allocator. > > Instead of declaring a union, we move its functionality behind a > few quick accessor functions. This way we could also much more > easily audit that it is being used correctly in debugging > scenarios. For instance, we could store a magic number in there > which could never get reused as a page->index and check that the > magic number exists in page_pfmemalloc(). > > Signed-off-by: Dave Hansen Acked-by: Kirill A. Shutemov -- Kirill A. Shutemov