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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 04896C04EB8 for ; Thu, 6 Dec 2018 08:46:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CA5CB20850 for ; Thu, 6 Dec 2018 08:46:14 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CA5CB20850 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729203AbeLFIqN (ORCPT ); Thu, 6 Dec 2018 03:46:13 -0500 Received: from mx1.redhat.com ([209.132.183.28]:54706 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727763AbeLFIqN (ORCPT ); Thu, 6 Dec 2018 03:46:13 -0500 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 5A1E630013B2; Thu, 6 Dec 2018 08:46:12 +0000 (UTC) Received: from xz-x1.nay.redhat.com (dhcp-14-116.nay.redhat.com [10.66.14.116]) by smtp.corp.redhat.com (Postfix) with ESMTP id 2172D19C7B; Thu, 6 Dec 2018 08:46:05 +0000 (UTC) From: Peter Xu To: linux-kernel@vger.kernel.org Cc: peterx@redhat.com, Andrea Arcangeli , Andrew Morton , "Kirill A. Shutemov" , Matthew Wilcox , Michal Hocko , Dave Jiang , "Aneesh Kumar K.V" , Souptick Joarder , Konstantin Khlebnikov , linux-mm@kvack.org Subject: [PATCH] mm: thp: fix soft dirty for migration when split Date: Thu, 6 Dec 2018 16:46:04 +0800 Message-Id: <20181206084604.17167-1-peterx@redhat.com> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.44]); Thu, 06 Dec 2018 08:46:12 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When splitting a huge migrating PMD, we'll transfer the soft dirty bit from the huge page to the small pages. However we're possibly using a wrong data since when fetching the bit we're using pmd_soft_dirty() upon a migration entry. Fix it up. CC: Andrea Arcangeli CC: Andrew Morton CC: "Kirill A. Shutemov" CC: Matthew Wilcox CC: Michal Hocko CC: Dave Jiang CC: "Aneesh Kumar K.V" CC: Souptick Joarder CC: Konstantin Khlebnikov CC: linux-mm@kvack.org CC: linux-kernel@vger.kernel.org Signed-off-by: Peter Xu --- I noticed this during code reading. Only compile tested. I'm sending a patch directly for review comments since it's relatively straightforward and not easy to test. Please have a look, thanks. --- mm/huge_memory.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index f2d19e4fe854..fb0787c3dd3b 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2161,7 +2161,10 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, SetPageDirty(page); write = pmd_write(old_pmd); young = pmd_young(old_pmd); - soft_dirty = pmd_soft_dirty(old_pmd); + if (unlikely(pmd_migration)) + soft_dirty = pmd_swp_soft_dirty(old_pmd); + else + soft_dirty = pmd_soft_dirty(old_pmd); /* * Withdraw the table only after we mark the pmd entry invalid. -- 2.17.1