From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751317Ab1CQFVM (ORCPT ); Thu, 17 Mar 2011 01:21:12 -0400 Received: from fgwmail6.fujitsu.co.jp ([192.51.44.36]:37080 "EHLO fgwmail6.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750822Ab1CQFVJ (ORCPT ); Thu, 17 Mar 2011 01:21:09 -0400 X-SecurityPolicyCheck-FJ: OK by FujitsuOutboundMailChecker v1.3.1 Message-ID: <4D819A2A.8050606@jp.fujitsu.com> Date: Thu, 17 Mar 2011 14:20:42 +0900 From: Hidetoshi Seto User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.0; ja; rv:1.9.2.15) Gecko/20110303 Thunderbird/3.1.9 MIME-Version: 1.0 To: Andi Kleen CC: Andrea Arcangeli , Andrew Morton , Huang Ying , Jin Dongming , linux-kernel@vger.kernel.org Subject: Re: [PATCH 3/4] Check whether pages are poisoned before copying References: <4D817234.9070106@jp.fujitsu.com> <4D8172D7.3040201@jp.fujitsu.com> <20110317041424.GD11094@one.firstfloor.org> In-Reply-To: <20110317041424.GD11094@one.firstfloor.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org (2011/03/17 13:14), Andi Kleen wrote: > On Thu, Mar 17, 2011 at 11:32:55AM +0900, Hidetoshi Seto wrote: >> So to avoid the above problem, add poison checks for both of 4K pages >> and the THP before copying in __collapse_huge_page_copy(). > > I don't think you need the check for the huge page -- it should not be allocated > in this case. Is there no case that the THP is once allocated but poison flag is set before copy? Though I know it is one of corner cases, having this check for THP is worse than nothing. Thanks, H.Seto