From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754007Ab0GHG7N (ORCPT ); Thu, 8 Jul 2010 02:59:13 -0400 Received: from one.firstfloor.org ([213.235.205.2]:36542 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753874Ab0GHG7M (ORCPT ); Thu, 8 Jul 2010 02:59:12 -0400 Date: Thu, 8 Jul 2010 08:49:51 +0200 From: Andi Kleen To: Naoya Horiguchi Cc: Andi Kleen , Andrew Morton , Mel Gorman , Wu Fengguang , "Jun'ichi Nomura" , linux-mm , LKML Subject: Re: [PATCH 6/7] hugetlb: hugepage migration core Message-ID: <20100708064951.GA15950@basil.fritz.box> References: <20100707092719.GA3900@basil.fritz.box> <20100708054426.GA19906@spritzera.linux.bs1.fc.nec.co.jp> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100708054426.GA19906@spritzera.linux.bs1.fc.nec.co.jp> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > This page cache is located on non-hugepage, isn't it? Yes. > If so, buffered IO is handled in the same manner as done for non-hugepage. > I think "hugepage under IO" is realized only in direct IO for now. > > Direct IO is issued in page unit even if the target page is in hugepage, > so locking each subpages separately looks natural for me than auditing > head page. Ok. Would need to make sure lock ordering is correctly handled all the time. If there's any code that locks multiple pages "backwards" and the migration code locks it forward there might be a problem. Maybe it's not a problem though. -Andi -- ak@linux.intel.com -- Speaking for myself only.