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,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 E5247C4646C for ; Mon, 24 Jun 2019 14:42:21 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 9F479208C3 for ; Mon, 24 Jun 2019 14:42:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fb.com header.i=@fb.com header.b="YbT/S+4j"; dkim=pass (1024-bit key) header.d=fb.onmicrosoft.com header.i=@fb.onmicrosoft.com header.b="YkUAdX/C" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9F479208C3 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=fb.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 13A378E0006; Mon, 24 Jun 2019 10:42:21 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 0EB058E0002; Mon, 24 Jun 2019 10:42:21 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id EA7088E0006; Mon, 24 Jun 2019 10:42:20 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from mail-qk1-f200.google.com (mail-qk1-f200.google.com [209.85.222.200]) by kanga.kvack.org (Postfix) with ESMTP id C6E738E0002 for ; Mon, 24 Jun 2019 10:42:20 -0400 (EDT) Received: by mail-qk1-f200.google.com with SMTP id c207so16328954qkb.11 for ; Mon, 24 Jun 2019 07:42:20 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:dkim-signature:dkim-signature:from:to:cc:subject :thread-topic:thread-index:date:message-id:references:in-reply-to :accept-language:content-language:content-id :content-transfer-encoding:mime-version; bh=biTD7+gjv13LBHVp56WKg5wlOTLn7gVlvfXmHII4/ok=; b=D0NmWqWwtDVDCM74xUa6Lzs/WfpoXQUg4fBn3M61hk31450njpFJSxoic5pRE5MjD3 vw7B39qmFealqmpP2JRluVxy/tHRM/eNvK0b5495KoL4E1ZmlJqZMrcBwt2VaiPIZMqG sOASn/Lwl1nbt/3VKhJz3c9l+gDjFWDh3yRB6qh6SBLB6g4fX6w2LTMVxQn+HNFmRVdH IPSSoTppRsEU8iKHeX+3LVNIO7lwzLzKbihN6y5QRAVor4EEAfBXHAAQJ04ZJajVC21B wflP55KALIpN8AaSuTNf1S24tpssYFwalWxsk+zB6t8sAmviopkZzx05bphhGQzDeqRY TdIQ== X-Gm-Message-State: APjAAAU6LtbZU0QFgFhc2j9rTNKFpCgkrxBJZw634fXl5auTHA8rNeaE AHVh7Otm10GhemkXPznvS0sX20w8hxOXK+qJII0X8XdTR5gpnREO3NrLpWFerXfJTepU9TIXkKE 24Me81Wq5Gt/7ZYSW8ZHlPFpsYBSElI5Ru/ksAnzSuKXR5+tZtY1SJvg6VJ0spqgwJw== X-Received: by 2002:a0c:acb5:: with SMTP id m50mr58040215qvc.82.1561387340567; Mon, 24 Jun 2019 07:42:20 -0700 (PDT) X-Google-Smtp-Source: APXvYqyILAB9QFvDOVWjSC6pl9dUva917X608OgQ/F+dyfyDMs6e8XSCLhkjpjjEU6WnY8Vlccw6 X-Received: by 2002:a0c:acb5:: with SMTP id m50mr58040165qvc.82.1561387339973; Mon, 24 Jun 2019 07:42:19 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1561387339; cv=none; d=google.com; s=arc-20160816; b=Xu3HwYiAWqqJjCgyxlXDPXWan3SON+/HEY3Rq9EL9aXzhS1DzJm/W0KO1j/NDF0maA rw7MTG1y8B0Y8NUW7H3rFV5vCcP886DqatbNO2WC44MnSVHbVliLHW0UPanfJ2I7AAL3 jDSVvpMadpQ8WlehT/ob8wDS+o/duUNRPscmcKejFjrbmE3G+wx7TI8xYdGUfASCx22U bPsistjRkdXzqrjz/PQkaX4yw6ie1WhhskR5/JbHzd9Y0IR0+4um9Qwc3pYHE0gF2Vue 9D5iGbn0zG31OCR4QFMJZ/VyhyDWRl1Esx8bfWB9VLAMqL23Cud2v+7ZlM5dmay/cDFp p5sA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:content-transfer-encoding:content-id:content-language :accept-language:in-reply-to:references:message-id:date:thread-index :thread-topic:subject:cc:to:from:dkim-signature:dkim-signature; bh=biTD7+gjv13LBHVp56WKg5wlOTLn7gVlvfXmHII4/ok=; b=Rl+zo9SGWlrcOb35sNxLWg1UIOYj5N+ltV+xe1igzOTBuYMMFd7Jf7L5ZLBCa3l3Ge RNq69mLUR2ITaa03ZwH+FnalWwBoMmNyMsM3EKn+Sl3L+0l3it9yMOy7k3/lHDfAUcD2 Rzk+YB+s5lHlg1VCmcqWGO9dklaZLf9USJtJSyZvvnBsrWuleoAcZWn9xo8VNnIKa1bN +XOix9cg+aKBuQ318jroZA8Jz6knWSrZGv8I4yu5ehIcpSK9IBn8KUwYzMbcF1lMA5DV 0mGLD6iNuVUiDhjjdXq1lKafMS+ZfDoC5+J8LWqPxktcLoih8TL4zpZC24plOmDUxfEN Uv7g== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@fb.com header.s=facebook header.b="YbT/S+4j"; dkim=pass header.i=@fb.onmicrosoft.com header.s=selector1-fb-onmicrosoft-com header.b="YkUAdX/C"; spf=pass (google.com: domain of prvs=1078cbd532=songliubraving@fb.com designates 67.231.153.30 as permitted sender) smtp.mailfrom="prvs=1078cbd532=songliubraving@fb.com"; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=fb.com Received: from mx0a-00082601.pphosted.com (mx0b-00082601.pphosted.com. [67.231.153.30]) by mx.google.com with ESMTPS id o51si7910351qvc.39.2019.06.24.07.42.19 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 24 Jun 2019 07:42:19 -0700 (PDT) Received-SPF: pass (google.com: domain of prvs=1078cbd532=songliubraving@fb.com designates 67.231.153.30 as permitted sender) client-ip=67.231.153.30; Authentication-Results: mx.google.com; dkim=pass header.i=@fb.com header.s=facebook header.b="YbT/S+4j"; dkim=pass header.i=@fb.onmicrosoft.com header.s=selector1-fb-onmicrosoft-com header.b="YkUAdX/C"; spf=pass (google.com: domain of prvs=1078cbd532=songliubraving@fb.com designates 67.231.153.30 as permitted sender) smtp.mailfrom="prvs=1078cbd532=songliubraving@fb.com"; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=fb.com Received: from pps.filterd (m0089730.ppops.net [127.0.0.1]) by m0089730.ppops.net (8.16.0.27/8.16.0.27) with SMTP id x5OEccID028211; Mon, 24 Jun 2019 07:42:17 -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=biTD7+gjv13LBHVp56WKg5wlOTLn7gVlvfXmHII4/ok=; b=YbT/S+4jHhwcBUnVmSpfg/CTv+qiHSa2j6QjIcDl18JMdRk2nD2uHIJn0YWv6JALpzJP zbKM8BWJoyqfL1UP4IfzjGvN3HFG8NaqMiWeipfrkyBgXjfur8uH8SzQ46voPT89jB5k oBswVWrhd05YwMe+wt7ccxbPEm0ffPSHj+k= Received: from mail.thefacebook.com (mailout.thefacebook.com [199.201.64.23]) by m0089730.ppops.net with ESMTP id 2tavm1rt2c-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-SHA384 bits=256 verify=NOT); Mon, 24 Jun 2019 07:42:16 -0700 Received: from prn-hub06.TheFacebook.com (2620:10d:c081:35::130) by prn-hub04.TheFacebook.com (2620:10d:c081:35::128) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id 15.1.1713.5; Mon, 24 Jun 2019 07:42:14 -0700 Received: from NAM02-CY1-obe.outbound.protection.outlook.com (192.168.54.28) by o365-in.thefacebook.com (192.168.16.30) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id 15.1.1713.5 via Frontend Transport; Mon, 24 Jun 2019 07:42:14 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.onmicrosoft.com; s=selector1-fb-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=biTD7+gjv13LBHVp56WKg5wlOTLn7gVlvfXmHII4/ok=; b=YkUAdX/CR/SfdHVD2JNUQSU0NdeTpCi0XH2ngMXk3QgAFuyId43CFQgdiD3JMPNU8Me9i1wasfDlGvSxp4wND/MJUTfmwE8lFwqyP/0j0ydaC2WuIBw3K9gqiG9DSGFn7kkJUw7a0GaD1Talvx9ix+l4HTZVMBcRRlVHi2s5P5w= Received: from MWHPR15MB1165.namprd15.prod.outlook.com (10.175.3.22) by MWHPR15MB1807.namprd15.prod.outlook.com (10.174.255.135) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.2008.16; Mon, 24 Jun 2019 14:42:13 +0000 Received: from MWHPR15MB1165.namprd15.prod.outlook.com ([fe80::400e:e329:ea98:aa0d]) by MWHPR15MB1165.namprd15.prod.outlook.com ([fe80::400e:e329:ea98:aa0d%6]) with mapi id 15.20.2008.014; Mon, 24 Jun 2019 14:42:13 +0000 From: Song Liu To: "Kirill A. Shutemov" CC: "linux-mm@kvack.org" , "linux-fsdevel@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "matthew.wilcox@oracle.com" , "kirill.shutemov@linux.intel.com" , Kernel Team , "william.kucharski@oracle.com" , "akpm@linux-foundation.org" , "hdanton@sina.com" Subject: Re: [PATCH v7 5/6] mm,thp: add read-only THP support for (non-shmem) FS Thread-Topic: [PATCH v7 5/6] mm,thp: add read-only THP support for (non-shmem) FS Thread-Index: AQHVKYdGAmz09KUZ80Kts9GVGsmXGaaqwvwAgAAUeoCAAAd4gIAABAcA Date: Mon, 24 Jun 2019 14:42:13 +0000 Message-ID: References: <20190623054749.4016638-1-songliubraving@fb.com> <20190623054749.4016638-6-songliubraving@fb.com> <20190624124746.7evd2hmbn3qg3tfs@box> <52BDA50B-7CBF-4333-9D15-0C17FD04F6ED@fb.com> <20190624142747.chy5s3nendxktm3l@box> In-Reply-To: <20190624142747.chy5s3nendxktm3l@box> 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:d642] x-ms-publictraffictype: Email x-ms-office365-filtering-correlation-id: 45d81ac6-ac3e-48e2-beae-08d6f8b2257b x-microsoft-antispam: BCL:0;PCL:0;RULEID:(2390118)(7020095)(4652040)(8989299)(4534185)(4627221)(201703031133081)(201702281549075)(8990200)(5600148)(711020)(4605104)(1401327)(2017052603328)(7193020);SRVR:MWHPR15MB1807; x-ms-traffictypediagnostic: MWHPR15MB1807: x-microsoft-antispam-prvs: x-ms-oob-tlc-oobclassifiers: OLM:7691; x-forefront-prvs: 007814487B x-forefront-antispam-report: SFV:NSPM;SFS:(10019020)(396003)(136003)(366004)(346002)(376002)(39860400002)(189003)(199004)(6506007)(76176011)(81166006)(4326008)(14454004)(229853002)(8936002)(33656002)(478600001)(81156014)(316002)(305945005)(446003)(11346002)(486006)(476003)(2906002)(68736007)(54906003)(71190400001)(2616005)(7736002)(46003)(6916009)(5660300002)(99286004)(86362001)(102836004)(53546011)(186003)(6116002)(50226002)(71200400001)(14444005)(256004)(53936002)(6486002)(6246003)(6436002)(8676002)(57306001)(66946007)(36756003)(6512007)(66446008)(25786009)(64756008)(66556008)(66476007)(73956011)(76116006)(142933001);DIR:OUT;SFP:1102;SCL:1;SRVR:MWHPR15MB1807;H:MWHPR15MB1165.namprd15.prod.outlook.com;FPR:;SPF:None;LANG:en;PTR:InfoNoRecords;MX:1;A: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: Lk/CUEMV78I14ydrlsW5qgP88OvuK0x0jsbMzojChZI4NXsxs7L5JIxUdB54ovFl1olcDjTDROkr4Bxf3UCCcY9zKBFkQfnr9nubd1XPluSCROzP5cicyHWygeW7Dz9wtOGA6diNLFhvJ3YyYBl2Of5B3kpBr1lm8yb3eZznP6vPttZz8I2dc9HoEuIdPl/L3SvjRKw3XeYoH5i3JFSRjdDlFdp9+mmiCkX44tOgfqQWizoSz5Xb21BnIUwfeOvOebo+jvrnGsBU8sFkm9IYLJ00a0t+fRwgmGSpoCC95AxAF6hoZ1ujDhN1Fko5AYpBQfmVYXr2cKltW9YnoZG/n7Iw8hXP+2bT0OWGVrO3a/nyZlzul1gupwRB09UVlxxGZuZXW2ieBDJxVuQ1LBRiV/gTVYbg24l55bwIFHQ7qIw= Content-Type: text/plain; charset="us-ascii" Content-ID: <2A04ABA06972B54D9DEF657049A91AAE@namprd15.prod.outlook.com> Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-MS-Exchange-CrossTenant-Network-Message-Id: 45d81ac6-ac3e-48e2-beae-08d6f8b2257b X-MS-Exchange-CrossTenant-originalarrivaltime: 24 Jun 2019 14:42:13.4296 (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: MWHPR15MB1807 X-OriginatorOrg: fb.com X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-06-24_10:,, 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=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1906240119 X-FB-Internal: deliver 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 Jun 24, 2019, at 7:27 AM, Kirill A. Shutemov wr= ote: >=20 > On Mon, Jun 24, 2019 at 02:01:05PM +0000, Song Liu wrote: >>>> @@ -1392,6 +1403,23 @@ static void collapse_file(struct mm_struct *mm, >>>> result =3D SCAN_FAIL; >>>> goto xa_unlocked; >>>> } >>>> + } else if (!page || xa_is_value(page)) { >>>> + xas_unlock_irq(&xas); >>>> + page_cache_sync_readahead(mapping, &file->f_ra, file, >>>> + index, PAGE_SIZE); >>>> + lru_add_drain(); >>>=20 >>> Why? >>=20 >> isolate_lru_page() is likely to fail if we don't drain the pagevecs.=20 >=20 > Please add a comment. Will do.=20 >=20 >>>> + page =3D find_lock_page(mapping, index); >>>> + if (unlikely(page =3D=3D NULL)) { >>>> + result =3D SCAN_FAIL; >>>> + goto xa_unlocked; >>>> + } >>>> + } else if (!PageUptodate(page)) { >>>=20 >>> Maybe we should try wait_on_page_locked() here before give up? >>=20 >> Are you referring to the "if (!PageUptodate(page))" case?=20 >=20 > Yes. I think this case happens when another thread is reading the page in.=20 I could not think of a way to trigger this condition for testing.=20 On the other hand, with current logic, we will retry the page on the=20 next scan, so I guess this is OK.=20 Thanks, Song=