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=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_MUTT autolearn=unavailable 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 A5C10C10F00 for ; Mon, 25 Feb 2019 18:50:36 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 62B8E2087C for ; Mon, 25 Feb 2019 18:50:36 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 62B8E2087C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.ibm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id EBD3C8E0009; Mon, 25 Feb 2019 13:50:35 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id E6C218E0004; Mon, 25 Feb 2019 13:50:35 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id CE8158E0009; Mon, 25 Feb 2019 13:50:35 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from mail-pl1-f197.google.com (mail-pl1-f197.google.com [209.85.214.197]) by kanga.kvack.org (Postfix) with ESMTP id 8A2728E0004 for ; Mon, 25 Feb 2019 13:50:35 -0500 (EST) Received: by mail-pl1-f197.google.com with SMTP id f65so3736050plb.3 for ; Mon, 25 Feb 2019 10:50:35 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-original-authentication-results:x-gm-message-state:date:from:to :cc:subject:references:mime-version:content-disposition:in-reply-to :user-agent:message-id; bh=qcjyfg1lJys5F840SIp1/Xpqy4pO4nAzr0Xj6SXU3L8=; b=mXgRdBmHERo3IEWmQB2MAe1k9wo7YVNUR8xedB78azpFDwL4r+n82qq/WW7ZRBZgja Nwr3j0y53mIlRiz+UNYaT65ln8KsBZ9sqSEteG0atGfiSuPD2KWBpE8aBY05bzZoJH7u 5QPIUR7x/Rm5U7MnT9xF07+DhMrBYlffILnSsstvvPzaGlTLcZAndy1His2P8xDM25tw 3SQAHK+JonS1Q3wka76wGs5lcyCca8IOU1gQ8Mnn2L6y3lo1IrtlfNloS4/djSwp3rp9 hHpiif4exxQjpB86aeu4HaZ4VRW20vuTcwZQ3sVvscvQ3Op2Lgdz98Xuk5oQMAj+DW/d +UEw== X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of rppt@linux.ibm.com designates 148.163.156.1 as permitted sender) smtp.mailfrom=rppt@linux.ibm.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=ibm.com X-Gm-Message-State: AHQUAub9m2qZEFi3i1QiqSDLgq5oXWDmFDFMnvZkXYqBmEqJgMgP3ohC yiI6JDNkPBT7Hbbep86+PRSbi3JOZXdvlILQFa4uFP6987mzz4pk6WWMa7X49wLZH1uRLoyuMlm S5Ao7kuaP3qaG+K94bMAmShB+RaKrlJ1z+2yL0vmC+AcH6xyVZAC9ZL1wpP6Qh99tAQ== X-Received: by 2002:a17:902:d208:: with SMTP id t8mr29208ply.78.1551120635223; Mon, 25 Feb 2019 10:50:35 -0800 (PST) X-Google-Smtp-Source: AHgI3IZRI65wU1DqyELP30JmWw+v74BeW7cFTnNSA734JAn25y4YwqmF3sUH7xULHU2ihrQ6umdF X-Received: by 2002:a17:902:d208:: with SMTP id t8mr29151ply.78.1551120634241; Mon, 25 Feb 2019 10:50:34 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1551120634; cv=none; d=google.com; s=arc-20160816; b=UZ/tyRU8/aWlACf9Z6C8VRN6myieOAFDq0IAJTP7iskxEZbxVpn/W9jXrKLqRTcv85 6z7pxgTdqWr4APKf3Pnyqp+lJULti/YaBJyBp4BkmDmWLylow6BP+ovCoKdlbx490TyU LQjjInMdk6ABO+/ETTStpZ/d241LHClcc/HH/TNxSZNhe5VzaT7yaKNu8T1+cDHowmbV fD4L/X+jCdltBq/BiRT5+5FoW7DIFj6rEE1aoBY8XleYJ7dubX5haD1EWY+80XRdfkiI grGxkdpem4LHl/JXM3b79RWclkfbqn4swE7UZ5uhUXWWWbO5TI/AKIxdJJUyX8yGZCC2 tT/A== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=message-id:user-agent:in-reply-to:content-disposition:mime-version :references:subject:cc:to:from:date; bh=qcjyfg1lJys5F840SIp1/Xpqy4pO4nAzr0Xj6SXU3L8=; b=dLkFnhfeZoD/8ZHztfE512lD5uyzFarbY8JTqraK8bgbpRRnmTR+JRWlNmrbdxcX02 vvmC66Q8wDb0pkb2SBZlxpDDiooRHlfj5qglMXnTW2ELrVQOSDbhwLktNbU9xzUhHplX FfSXYA1praZdoOw7fnn0m6uxXzkyG/6+xZTThumajkiJrE8IKrk/y8sc/OpRO3I0oVFG INsx30qFU9VoG6/Tb8sBhlNqiD8tB2QSkdgmlRdkI1hnXHTEH9sFVaS0fVaJofC6FgCx IUq9F31O9VuxPy9U6JXdnE1QNAdizTc1f/7aLEEC7IZLDJgpCkvYSE5qT9luVo/NPJd9 zTiQ== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of rppt@linux.ibm.com designates 148.163.156.1 as permitted sender) smtp.mailfrom=rppt@linux.ibm.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=ibm.com Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com. [148.163.156.1]) by mx.google.com with ESMTPS id l10si9221901pgp.25.2019.02.25.10.50.34 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 25 Feb 2019 10:50:34 -0800 (PST) Received-SPF: pass (google.com: domain of rppt@linux.ibm.com designates 148.163.156.1 as permitted sender) client-ip=148.163.156.1; Authentication-Results: mx.google.com; spf=pass (google.com: domain of rppt@linux.ibm.com designates 148.163.156.1 as permitted sender) smtp.mailfrom=rppt@linux.ibm.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=ibm.com Received: from pps.filterd (m0098399.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x1PIie1p053368 for ; Mon, 25 Feb 2019 13:50:33 -0500 Received: from e06smtp05.uk.ibm.com (e06smtp05.uk.ibm.com [195.75.94.101]) by mx0a-001b2d01.pphosted.com with ESMTP id 2qvkjyrahx-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Mon, 25 Feb 2019 13:50:33 -0500 Received: from localhost by e06smtp05.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 25 Feb 2019 18:50:30 -0000 Received: from b06cxnps3074.portsmouth.uk.ibm.com (9.149.109.194) by e06smtp05.uk.ibm.com (192.168.101.135) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Mon, 25 Feb 2019 18:50:25 -0000 Received: from d06av26.portsmouth.uk.ibm.com (d06av26.portsmouth.uk.ibm.com [9.149.105.62]) by b06cxnps3074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x1PIoOGF58130614 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Mon, 25 Feb 2019 18:50:24 GMT Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 2A385AE051; Mon, 25 Feb 2019 18:50:24 +0000 (GMT) Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 1AEC3AE055; Mon, 25 Feb 2019 18:50:20 +0000 (GMT) Received: from rapoport-lnx (unknown [9.148.205.26]) by d06av26.portsmouth.uk.ibm.com (Postfix) with ESMTPS; Mon, 25 Feb 2019 18:50:19 +0000 (GMT) Date: Mon, 25 Feb 2019 20:50:15 +0200 From: Mike Rapoport To: Peter Xu Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, David Hildenbrand , Hugh Dickins , Maya Gokhale , Jerome Glisse , Pavel Emelyanov , Johannes Weiner , Martin Cracauer , Shaohua Li , Marty McFadden , Andrea Arcangeli , Mike Kravetz , Denis Plotnikov , Mike Rapoport , Mel Gorman , "Kirill A . Shutemov" , "Dr . David Alan Gilbert" Subject: Re: [PATCH v2 18/26] khugepaged: skip collapse if uffd-wp detected References: <20190212025632.28946-1-peterx@redhat.com> <20190212025632.28946-19-peterx@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190212025632.28946-19-peterx@redhat.com> User-Agent: Mutt/1.5.24 (2015-08-30) X-TM-AS-GCONF: 00 x-cbid: 19022518-0020-0000-0000-0000031B173B X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19022518-0021-0000-0000-0000216C796A Message-Id: <20190225185015.GK24917@rapoport-lnx> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-02-25_09:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1902250136 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, Feb 12, 2019 at 10:56:24AM +0800, Peter Xu wrote: > Don't collapse the huge PMD if there is any userfault write protected > small PTEs. The problem is that the write protection is in small page > granularity and there's no way to keep all these write protection > information if the small pages are going to be merged into a huge PMD. > > The same thing needs to be considered for swap entries and migration > entries. So do the check as well disregarding khugepaged_max_ptes_swap. > > Signed-off-by: Peter Xu Reviewed-by: Mike Rapoport > --- > include/trace/events/huge_memory.h | 1 + > mm/khugepaged.c | 23 +++++++++++++++++++++++ > 2 files changed, 24 insertions(+) > > diff --git a/include/trace/events/huge_memory.h b/include/trace/events/huge_memory.h > index dd4db334bd63..2d7bad9cb976 100644 > --- a/include/trace/events/huge_memory.h > +++ b/include/trace/events/huge_memory.h > @@ -13,6 +13,7 @@ > EM( SCAN_PMD_NULL, "pmd_null") \ > EM( SCAN_EXCEED_NONE_PTE, "exceed_none_pte") \ > EM( SCAN_PTE_NON_PRESENT, "pte_non_present") \ > + EM( SCAN_PTE_UFFD_WP, "pte_uffd_wp") \ > EM( SCAN_PAGE_RO, "no_writable_page") \ > EM( SCAN_LACK_REFERENCED_PAGE, "lack_referenced_page") \ > EM( SCAN_PAGE_NULL, "page_null") \ > diff --git a/mm/khugepaged.c b/mm/khugepaged.c > index 4f017339ddb2..396c7e4da83e 100644 > --- a/mm/khugepaged.c > +++ b/mm/khugepaged.c > @@ -29,6 +29,7 @@ enum scan_result { > SCAN_PMD_NULL, > SCAN_EXCEED_NONE_PTE, > SCAN_PTE_NON_PRESENT, > + SCAN_PTE_UFFD_WP, > SCAN_PAGE_RO, > SCAN_LACK_REFERENCED_PAGE, > SCAN_PAGE_NULL, > @@ -1123,6 +1124,15 @@ static int khugepaged_scan_pmd(struct mm_struct *mm, > pte_t pteval = *_pte; > if (is_swap_pte(pteval)) { > if (++unmapped <= khugepaged_max_ptes_swap) { > + /* > + * Always be strict with uffd-wp > + * enabled swap entries. Please see > + * comment below for pte_uffd_wp(). > + */ > + if (pte_swp_uffd_wp(pteval)) { > + result = SCAN_PTE_UFFD_WP; > + goto out_unmap; > + } > continue; > } else { > result = SCAN_EXCEED_SWAP_PTE; > @@ -1142,6 +1152,19 @@ static int khugepaged_scan_pmd(struct mm_struct *mm, > result = SCAN_PTE_NON_PRESENT; > goto out_unmap; > } > + if (pte_uffd_wp(pteval)) { > + /* > + * Don't collapse the page if any of the small > + * PTEs are armed with uffd write protection. > + * Here we can also mark the new huge pmd as > + * write protected if any of the small ones is > + * marked but that could bring uknown > + * userfault messages that falls outside of > + * the registered range. So, just be simple. > + */ > + result = SCAN_PTE_UFFD_WP; > + goto out_unmap; > + } > if (pte_write(pteval)) > writable = true; > > -- > 2.17.1 > -- Sincerely yours, Mike.