From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753219AbbBRACw (ORCPT ); Tue, 17 Feb 2015 19:02:52 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:37594 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752165AbbBRACv (ORCPT ); Tue, 17 Feb 2015 19:02:51 -0500 Date: Tue, 17 Feb 2015 16:02:49 -0800 From: Andrew Morton To: Naoya Horiguchi , Hugh Dickins , Michal Hocko , Mel Gorman , Johannes Weiner , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , Naoya Horiguchi Subject: Re: [PATCH v2] mm, hugetlb: set PageLRU for in-use/active hugepages Message-Id: <20150217160249.7d498e4bd0837748e8c6a5f0@linux-foundation.org> In-Reply-To: <20150217155744.04db5a98d5a1820240eb2317@linux-foundation.org> References: <1424143299-7557-1-git-send-email-n-horiguchi@ah.jp.nec.com> <20150217093153.GA12875@hori1.linux.bs1.fc.nec.co.jp> <20150217155744.04db5a98d5a1820240eb2317@linux-foundation.org> X-Mailer: Sylpheed 3.4.1 (GTK+ 2.24.23; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 17 Feb 2015 15:57:44 -0800 Andrew Morton wrote: > So if I'm understanding this correctly, hugepages never have PG_lru set > and so you are overloading that bit on hugepages to indicate that the > page is present on hstate->hugepage_activelist? And maybe we don't need to overload PG_lru at all? There's plenty of free space in the compound page's *(page + 1).