From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,HK_RANDOM_FROM,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A7A59C433E9 for ; Thu, 18 Mar 2021 05:35:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6238264F30 for ; Thu, 18 Mar 2021 05:35:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229600AbhCRFe7 (ORCPT ); Thu, 18 Mar 2021 01:34:59 -0400 Received: from mail.kingsoft.com ([114.255.44.146]:48652 "EHLO mail.kingsoft.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S229512AbhCRFeR (ORCPT ); Thu, 18 Mar 2021 01:34:17 -0400 X-AuditID: 0a580157-47bff70000021a79-00-6052df77c806 Received: from mail.kingsoft.com (localhost [10.88.1.32]) (using TLS with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client did not present a certificate) by mail.kingsoft.com (SMG-1-NODE-87) with SMTP id DB.61.06777.77FD2506; Thu, 18 Mar 2021 13:04:55 +0800 (HKT) Received: from alex-virtual-machine (172.16.253.254) by KSBJMAIL2.kingsoft.cn (10.88.1.32) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Thu, 18 Mar 2021 13:34:12 +0800 Date: Thu, 18 Mar 2021 13:34:12 +0800 From: Aili Yao To: Matthew Wilcox CC: David Hildenbrand , , , , , , , Oscar Salvador , Mike Kravetz , Subject: Re: [PATCH] mm/gup: check page posion status for coredump. Message-ID: <20210318133412.12078eb7@alex-virtual-machine> In-Reply-To: <20210318044600.GJ3420@casper.infradead.org> References: <20210317163714.328a038d@alex-virtual-machine> <20a0d078-f49d-54d6-9f04-f6b41dd51e5f@redhat.com> <20210318044600.GJ3420@casper.infradead.org> Organization: kingsoft X-Mailer: Claws Mail 3.17.5 (GTK+ 2.24.30; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Originating-IP: [172.16.253.254] X-ClientProxiedBy: KSBJMAIL1.kingsoft.cn (10.88.1.31) To KSBJMAIL2.kingsoft.cn (10.88.1.32) X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFvrELMWRmVeSWpSXmKPExsXCFcGooFt+PyjBYOlEcYs569ewWXxd/4vZ 4vKuOWwW99b8Z7X4uD/Y4mLjAUaLM9OKLH7/mMPmwOGxeYWWx6ZPk9g9Tsz4zeLx4upGFo+P T2+xeLzfd5XNY/Ppao/Pm+QCOKK4bFJSczLLUov07RK4Mq6dPMxWMJW74tOlrAbGBxxdjJwc EgImEm2Pf7N3MXJxCAlMZ5L4u+Q1E4TzilGid+07dpAqFgFViamn5zCB2GxA9q57s1i7GDk4 RAQ0JN5sMQKpZxbYwiSxu+ULM0iNsICzxObjM8FsXgEriS+ft4P1cgpYSpyYuoYFYsFcRomT n6aCLeAXEJPovfKfCeIke4m2LYsYIZoFJU7OfMICYjML6EicWHWMGcKWl9j+dg6YLSSgKHF4 yS92iF4liSPdM9gg7FiJZfNesU5gFJ6FZNQsJKNmIRm1gJF5FSNLcW664SZGSLSE72Cc1/RR 7xAjEwfjIUYJDmYlEV7TvIAEId6UxMqq1KL8+KLSnNTiQ4zSHCxK4rwiUUApgfTEktTs1NSC 1CKYLBMHp1QDU9zyWZfZCiWXr5Oa+jJt0lJNJX7hIzxnQqaybH91ximVrePulsVK73oYY/+J O/wNkOVYtz5Ncsd/dukAg2el34UkHKO5bR2m7beWO/c/Y0vUAy1GjsWTfW6f8j/fWbBr+yy/ 55vOLlr5MUHB7KWOi02W6JVGxw/2h8Ibm1c9OpHbUbmYMch7yb5a7pfFzpNNuTKk4p9Lskad ff/oz4p/RnF3Y+2eZKft3JdrsdFUa634hTeyKfM1jQpXxGk0Lrp/ZVrTUt6I66dnCZ9l32A4 i6fR8q3WlFjT7ibBKAVbmQ5bj7Vsf999apmtceFoiNqMBQu/VHhnqsWyrPTTLDMqTHhw5+RG 3fX7TjH2pmSJKbEUZyQaajEXFScCABxGk1IFAwAA Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 18 Mar 2021 04:46:00 +0000 Matthew Wilcox wrote: > On Wed, Mar 17, 2021 at 10:12:02AM +0100, David Hildenbrand wrote: > > > + if (IS_ENABLED(CONFIG_MEMORY_FAILURE) && ret == 1) { > > > + if (unlikely(PageHuge(page) && PageHWPoison(compound_head(page)))) > > > + ret = 0; > > > + else if (unlikely(PageHWPoison(page))) > > > + ret = 0; > > > + } > > > > I wonder if a simple > > > > if (PageHWPoison(compound_head(page))) > > ret = 0; > > > > won't suffice. But I guess the "issue" is compound pages that are not huge > > pages or transparent huge pages. > > THPs don't set the HWPoison bit on the head page. > > https://lore.kernel.org/linux-mm/20210316140947.GA3420@casper.infradead.org/ > > (and PAGEFLAG(HWPoison, hwpoison, PF_ANY)) > > By the way, > > #ifdef CONFIG_MEMORY_FAILURE > PAGEFLAG(HWPoison, hwpoison, PF_ANY) > TESTSCFLAG(HWPoison, hwpoison, PF_ANY) > #define __PG_HWPOISON (1UL << PG_hwpoison) > extern bool take_page_off_buddy(struct page *page); > #else > PAGEFLAG_FALSE(HWPoison) > #define __PG_HWPOISON 0 > #endif > > so there's no need for this > if (IS_ENABLED(CONFIG_MEMORY_FAILURE) > check, as it simply turns into > > if (PageHuge(page) && 0) > else if (0) > > and the compiler can optimise it all away. Yes, You are right, I will modify this later. Thanks for correction -- Thanks! Aili Yao