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=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 C44BCC7618F for ; Fri, 26 Jul 2019 21:20:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8E4D422BE8 for ; Fri, 26 Jul 2019 21:20:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fb.com header.i=@fb.com header.b="GDd2/Bif"; dkim=pass (1024-bit key) header.d=fb.onmicrosoft.com header.i=@fb.onmicrosoft.com header.b="VJc46yTU" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728325AbfGZVUf (ORCPT ); Fri, 26 Jul 2019 17:20:35 -0400 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:34212 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726102AbfGZVUf (ORCPT ); Fri, 26 Jul 2019 17:20:35 -0400 Received: from pps.filterd (m0109334.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x6QLHUtC008904; Fri, 26 Jul 2019 14:19:57 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : references : in-reply-to : content-type : content-id : content-transfer-encoding : mime-version; s=facebook; bh=jVnRWhXm2MWCV1Qc5izacs5GiuNHypcF1Ji6eqWRSVs=; b=GDd2/BifOW6FME0UHZB3Ztga0MHxlksvfUGzkmrL1yqGNuaP0t+U8cu5jlWZK+wyLDLW 6YJ8m6ChHtJnFFRDWoAuvy4+c5V1hW90/2oeMRW8ocImjVjfopI+Zop7cuc1tW+oleRh vzbiVVtbAJkB+nevgVVFA1bxzbHgS0JikwI= Received: from maileast.thefacebook.com ([163.114.130.16]) by mx0a-00082601.pphosted.com with ESMTP id 2u02eb9qpx-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT); Fri, 26 Jul 2019 14:19:56 -0700 Received: from ash-exhub101.TheFacebook.com (2620:10d:c0a8:82::e) by ash-exhub103.TheFacebook.com (2620:10d:c0a8:82::c) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1713.5; Fri, 26 Jul 2019 14:19:55 -0700 Received: from NAM02-BL2-obe.outbound.protection.outlook.com (100.104.31.183) by o365-in.thefacebook.com (100.104.35.173) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256) id 15.1.1713.5 via Frontend Transport; Fri, 26 Jul 2019 14:19:55 -0700 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=mUv2Rgmw0JEXe+8Os+s7g2qKB+4vJazLXSS8LqDR7NN766nZwayjSi4klqRSkDR06C4VrQKhPiZQrCKHA9czKBkRrbL2sPSiwfkqis7+e7JkdxJSN6Bawp7yflYMSenFuQY93h3RwOP2jXTBUtRgbqoNpdNppevFzRlMgtVjgKgPhA/wNbGwF9IjlZDovsrEiB6We4QN/qciitxFC0KjpgW0SqIHp7KBlpyBSqLFsF9hw7Dv09mYWVfr+bJNGk3ebOBUtG03Cn2lxlOhkpxydN1reUpPJJ9S9KJIhA/I2qTmBtLotPPqOK0qca/qRW/RLV2Al+G2vAoONiEVedTP8g== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=jVnRWhXm2MWCV1Qc5izacs5GiuNHypcF1Ji6eqWRSVs=; b=htf+1g10xLW9/JYhj45EQV6sNqC7v84F4TGe+ajpys9MyTwU0i1C7Ni9kjyom0RT6SXkCsPi/22fqgJutb0x2mGB/sjNnXUNqN6l4cY638E660iwM8PChCpCVrL+1IiPaB4fShUN3+TBY2eVrGPqig9762hPTwpcNNU6/ZFSFMfjiy4Cu8m+UvI2CIQ89sCv3Z7tdhDD3GaW6Qv6eCiQyQWIkvliaoRP1uV4DYqrJLc2LIGzoda7mKLXMG52m60jOdL30gaVTX7TP6dfcElHJSvVKXBAww++FXxw8099R9oWqk81MD2+QeywnZPyMKzQbptXp9ZYpv7tb5lJ0ZI+VA== ARC-Authentication-Results: i=1; mx.microsoft.com 1;spf=pass smtp.mailfrom=fb.com;dmarc=pass action=none header.from=fb.com;dkim=pass header.d=fb.com;arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.onmicrosoft.com; s=selector2-fb-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=jVnRWhXm2MWCV1Qc5izacs5GiuNHypcF1Ji6eqWRSVs=; b=VJc46yTU0dfVj3ldRlDlfbkiWLcz1y0Qc6EmLjEX7mrsDnHhVX1iz729W69xGK8Tr/PpxVToBR5+5A+7km34DT7kuW87bEapBqvT8Hwid6MzRImrRTRA5hXjfpnVEcyGVT2UXBPzhVE+1oK+ESTY5iXDKIGXEjUHt02+7w/I084= Received: from MWHPR15MB1165.namprd15.prod.outlook.com (10.175.3.22) by MWHPR15MB1902.namprd15.prod.outlook.com (10.174.255.21) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.2094.16; Fri, 26 Jul 2019 21:19:54 +0000 Received: from MWHPR15MB1165.namprd15.prod.outlook.com ([fe80::4066:b41c:4397:27b7]) by MWHPR15MB1165.namprd15.prod.outlook.com ([fe80::4066:b41c:4397:27b7%7]) with mapi id 15.20.2094.013; Fri, 26 Jul 2019 21:19:54 +0000 From: Song Liu To: Oleg Nesterov CC: lkml , Linux-MM , "Andrew Morton" , "matthew.wilcox@oracle.com" , "kirill.shutemov@linux.intel.com" , "peterz@infradead.org" , "rostedt@goodmis.org" , "Kernel Team" , "william.kucharski@oracle.com" Subject: Re: [PATCH v8 2/4] uprobe: use original page when all uprobes are removed Thread-Topic: [PATCH v8 2/4] uprobe: use original page when all uprobes are removed Thread-Index: AQHVQfsnepoAlMhPK0qmuIU0gpphb6bZpE2AgAB5kgCAAOAOAIAAqHSAgADyToCAANMVgA== Date: Fri, 26 Jul 2019 21:19:54 +0000 Message-ID: <4398BBD5-31AB-4342-9572-32763B016175@fb.com> References: <20190724083600.832091-1-songliubraving@fb.com> <20190724083600.832091-3-songliubraving@fb.com> <20190724113711.GE21599@redhat.com> <20190725081414.GB4707@redhat.com> <20190726084423.GA16112@redhat.com> In-Reply-To: <20190726084423.GA16112@redhat.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-mailer: Apple Mail (2.3445.104.11) x-originating-ip: [2620:10d:c090:180::1:bb04] x-ms-publictraffictype: Email x-ms-office365-filtering-correlation-id: bb4ea2bf-d7ea-4df1-4355-08d7120f00c9 x-microsoft-antispam: BCL:0;PCL:0;RULEID:(2390118)(7020095)(4652040)(8989299)(4534185)(4627221)(201703031133081)(201702281549075)(8990200)(5600148)(711020)(4605104)(1401327)(2017052603328)(7193020);SRVR:MWHPR15MB1902; x-ms-traffictypediagnostic: MWHPR15MB1902: x-microsoft-antispam-prvs: x-ms-oob-tlc-oobclassifiers: OLM:8273; x-forefront-prvs: 01106E96F6 x-forefront-antispam-report: SFV:NSPM;SFS:(10019020)(396003)(39860400002)(346002)(366004)(376002)(136003)(52314003)(199004)(189003)(14454004)(486006)(6116002)(229853002)(6436002)(25786009)(50226002)(8676002)(46003)(316002)(256004)(6512007)(53936002)(478600001)(99286004)(476003)(54906003)(5660300002)(446003)(305945005)(186003)(14444005)(2616005)(76176011)(11346002)(86362001)(6486002)(53546011)(71190400001)(64756008)(33656002)(71200400001)(68736007)(76116006)(102836004)(66446008)(2906002)(6916009)(6246003)(66946007)(36756003)(4326008)(6506007)(81156014)(4744005)(57306001)(8936002)(91956017)(81166006)(66476007)(66556008)(7736002);DIR:OUT;SFP:1102;SCL:1;SRVR:MWHPR15MB1902;H:MWHPR15MB1165.namprd15.prod.outlook.com;FPR:;SPF:None;LANG:en;PTR:InfoNoRecords;A:1;MX:1; received-spf: None (protection.outlook.com: fb.com does not designate permitted sender hosts) x-ms-exchange-senderadcheck: 1 x-microsoft-antispam-message-info: v8CgET2JkHFHThws0wOB1vMi97P7LEaiDWlJmwDXBc4vgsVlB2/o9A1XTyHSxXbKsGy6WKloWW4DpF3f1ao2p06o8hhs5DfyZJnDiN6IEnCCwZdxxrSAY6F8cE0Tjz62FpxeNEXIN9W2Lu6TOeizRHxpEV5ZKkQuOvFbH7ewXHWoRaAzQVqPpoUH7B6ec3OebsF8qRnHEon8L+/vYokuWGb35CdPNg+4fdUjnb1GvKBNXcGf1YRTdQpqpyXicDzRh5vs/oEy9m3NW80YcEmWrU21CLvWVa6OkF/IaOh4P5oIsxnG3I91CfuM91BgHafQoz8CnndFlnx1u65SjgRX3cTHHpQ8eWlRl1tHal53QAB8jZhq8rIHP4MT8UGCHHIt95XxW3Fk75do/r9q3xYdVfjvvC14eDywqn1QZWkfiEs= Content-Type: text/plain; charset="us-ascii" Content-ID: <8092EDAF1C73394291E86563B64E33D3@namprd15.prod.outlook.com> Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-MS-Exchange-CrossTenant-Network-Message-Id: bb4ea2bf-d7ea-4df1-4355-08d7120f00c9 X-MS-Exchange-CrossTenant-originalarrivaltime: 26 Jul 2019 21:19:54.0952 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 8ae927fe-1255-47a7-a2af-5f3a069daaa2 X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: songliubraving@fb.com X-MS-Exchange-Transport-CrossTenantHeadersStamped: MWHPR15MB1902 X-OriginatorOrg: fb.com X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-07-26_15:,, signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=710 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1906280000 definitions=main-1907260241 X-FB-Internal: deliver Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > On Jul 26, 2019, at 1:44 AM, Oleg Nesterov wrote: >=20 > On 07/25, Song Liu wrote: >>=20 >> I guess I know the case now. We can probably avoid this with an simp=10l= e=20 >> check for old_page =3D=3D new_page? >=20 > better yet, I think we can check PageAnon(old_page) and avoid the unneces= sary > __replace_page() in this case. See the patch below. I added PageAnon(old_page) check in v9 of the patch.=20 >=20 > Anyway, why __replace_page() needs to lock both pages? This doesn't look = nice > even if it were correct. I think it can do lock_page(old_page) later. >=20 Agreed. I have changed the v9 to only unmap old_page. So it should be clean= er.=20 Thanks again for these good suggestions, Song=