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Miller" , David Sterba , Josef Bacik , Dave Hansen , Bob Kasten , Mike Kravetz , "Chad Mynhier" , "Kirill A. Shutemov" , Johannes Weiner , "Matthew Wilcox" , Dave Airlie , "Vlastimil Babka" , Keith Busch , Ralph Campbell , Steve Capper , Dave Chinner , Sean Christopherson , Hugh Dickins , Ilya Dryomov , Alexander Duyck , Thomas Gleixner , =?iso-8859-1?Q?J=E9r=F4me_Glisse?= , Amir Goldstein , Jason Gunthorpe , Michal Hocko , Jann Horn , David Howells , John Hubbard , Souptick Joarder , "john.hubbard@gmail.com" , Jan Kara , Andrey Konovalov , Arun KS , Aneesh Kumar K.V , Jeff Layton , Yangtao Li , Andrew Morton , "Robin Murphy" , Mike Rapoport , "David Rientjes" , Andrey Ryabinin , Yafang Shao , Huang Shijie , "Yang Shi" , Miklos Szeredi , Pavel Tatashin , Kirill Tkhai , Sage Weil , Ira Weiny , Dan Williams , "Darrick J. Wong" , Gao Xiang , "Bartlomiej Zolnierkiewicz" , Ross Zwisler Subject: Re: [PATCH v2 2/2] mm,thp: Add experimental config option RO_EXEC_FILEMAP_HUGE_FAULT_THP Thread-Topic: [PATCH v2 2/2] mm,thp: Add experimental config option RO_EXEC_FILEMAP_HUGE_FAULT_THP Thread-Index: AQHVRlIkIBeF3SPMIUmfTIWhM30vRKbiM5WAgAEBOgCAAFSkgA== Date: Tue, 30 Jul 2019 19:14:47 +0000 Message-ID: <1D97995B-E3A6-4397-AA99-2E7B90534559@fb.com> References: <20190729210933.18674-1-william.kucharski@oracle.com> <20190729210933.18674-3-william.kucharski@oracle.com> In-Reply-To: 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:c090:200::3:5cb8] x-ms-publictraffictype: Email x-ms-office365-filtering-correlation-id: 03adb8e9-aca7-4801-9873-08d71522301b x-microsoft-antispam: BCL:0;PCL:0;RULEID:(2390118)(7020095)(4652040)(8989299)(4534185)(4627221)(201703031133081)(201702281549075)(8990200)(5600148)(711020)(4605104)(1401327)(2017052603328)(7193020);SRVR:MWHPR15MB1520; x-ms-traffictypediagnostic: MWHPR15MB1520: x-microsoft-antispam-prvs: x-ms-oob-tlc-oobclassifiers: OLM:8882; x-forefront-prvs: 0114FF88F6 x-forefront-antispam-report: SFV:NSPM;SFS:(10019020)(396003)(136003)(346002)(366004)(39860400002)(376002)(199004)(189003)(36756003)(6512007)(53936002)(71200400001)(71190400001)(8676002)(81156014)(7736002)(50226002)(81166006)(305945005)(68736007)(64756008)(5660300002)(8936002)(7416002)(76116006)(66446008)(66556008)(66476007)(7406005)(7366002)(66946007)(446003)(99286004)(46003)(6436002)(6486002)(57306001)(186003)(11346002)(2906002)(53546011)(6506007)(478600001)(316002)(14454004)(54906003)(6246003)(4326008)(256004)(6116002)(25786009)(76176011)(86362001)(33656002)(486006)(229853002)(102836004)(2616005)(6916009)(476003)(142933001)(14583001);DIR:OUT;SFP:1102;SCL:1;SRVR:MWHPR15MB1520;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: DcczXJnBs6wroH2ga6LynzGq4T5M0W0x6H0P0gzoPmPv+kJkTnEXqH1kpgkK3vjmUMLMa8V/l+aReLEnJ42DvBxWtzWR/p1zPLiQ/vO1xFKMUpfyOOLHOgbQSlg8DJSKRenvieiyZsQ+ou+qj0OVos++x2fLkxCc8t0Twb0rAfTRQ6StDuJbBqWEPKyeOKusy2rq5oC/ISfm9b/1rscoLM3DZ2AznUGfOcZ+huG01gymHtlOdvvioFMW4DEkOkVW0UA8N5McZMObjhqm7SK57D18/1RGUy4j1rIZqWdftRlcCWRgde6iEtsbLn4FRmOzWScBkPiGgMMUGxvYkXzrPEPJ6Zm+C/KKmZTaxBDndziS5zD/byfBqdmy7RjOuG02R6JOD+Q/01JRw9LCXzeKqipBfc5r+0Ar9o7BSkJK/Qw= Content-Type: text/plain; charset="iso-8859-1" Content-ID: <3D2E2C12A13A2842AAE6A44FC1165839@namprd15.prod.outlook.com> Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-MS-Exchange-CrossTenant-Network-Message-Id: 03adb8e9-aca7-4801-9873-08d71522301b X-MS-Exchange-CrossTenant-originalarrivaltime: 30 Jul 2019 19:14:47.2377 (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: MWHPR15MB1520 X-OriginatorOrg: fb.com X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-07-30_09:,, 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=8.0.1-1906280000 definitions=main-1907300193 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 Jul 30, 2019, at 7:11 AM, William Kucharski wrote: >=20 >=20 >=20 > On 7/29/19 4:51 PM, Song Liu wrote: >=20 >>=20 >>> +#define HPAGE_PMD_OFFSET (HPAGE_PMD_SIZE - 1) >> ^ space vs. tab difference here. >=20 > Thanks, good catch! >=20 >>> +#define HPAGE_PMD_MASK (~(HPAGE_PMD_OFFSET)) >>> + >>> +#define HPAGE_PUD_SHIFT PUD_SHIFT >>> +#define HPAGE_PUD_SIZE ((1UL) << HPAGE_PUD_SHIFT) >>> +#define HPAGE_PUD_OFFSET (HPAGE_PUD_SIZE - 1) >=20 > Saw this one, too. >=20 >> Should HPAGE_PMD_OFFSET and HPAGE_PUD_OFFSET include bits for >> PAGE_OFFSET? I guess we can just keep huge_mm.h as-is and use >> ~HPAGE_PMD_MASK. >=20 > That's what I had intended; would you rather see those macros > omit the unneeded for the larger page size bits? I think using ~HPAGE_PMD_MASK is common practice. Let's keep it=20 that way.=20 >=20 >>> - * - FGP_PMD: If FGP_CREAT is specified, attempt to allocate a PMD-siz= ed page. >>> + * - FGP_PMD: If FGP_CREAT is specified, attempt to allocate a PMD-siz= ed page >=20 > No - this came in as part of patch 1/2 and I missed dropping the period a= t the end of the line that caused this to be a diff, so I will put it > back. :-) >=20 >> We have been using name "xas" for "struct xa_state *". Let's keep using = it? >=20 > Thanks, done. >=20 >>> + if (unlikely(!(PageCompound(new_page)))) { >> What condition triggers this case > I wanted a check to make sure that __page_cacke_alloc() returned a large = page. I don't recall if the mechanism guarantees that when you ask for > a large page, you get one, so I wanted to handle that case. >=20 > If you prefer, I could make this a VM_BUG_ON_PAGE() instead, but I > wanted it to fallback gracefully if it can't get a properly sized > page. I think __page_cache_alloc() guarantees compound page. If not, it should return NULL.=20 >=20 >>> +#ifndef COMPOUND_PAGES_HEAD_ONLY >> Where do we define COMPOUND_PAGES_HEAD_ONLY? >=20 > At present, we do not. >=20 > I used this so I could include the code that would be needed once > Matthew's "store only head pages in page cache" changes go back in, > which looks like it may not be until 5.4-rc1. Matthew recommended I We don't have to wait until 5.4-rc1. We could develop based on this=20 patch once it lands in mm tree.=20 Thanks, Song