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Shutemov" CC: LKML , Linux-MM , "namit@vmware.com" , "peterz@infradead.org" , "oleg@redhat.com" , "rostedt@goodmis.org" , "mhiramat@kernel.org" , "matthew.wilcox@oracle.com" , "kirill.shutemov@linux.intel.com" , Kernel Team , "william.kucharski@oracle.com" , "chad.mynhier@oracle.com" , "mike.kravetz@oracle.com" Subject: Re: [PATCH uprobe, thp 4/4] uprobe: collapse THP pmd after removing all uprobes Thread-Topic: [PATCH uprobe, thp 4/4] uprobe: collapse THP pmd after removing all uprobes Thread-Index: AQHVFmai8W5Yq1+OvE6IJWAoNhoGxKaDl3SAgABVaoA= Date: Thu, 30 May 2019 17:26:38 +0000 Message-ID: <4E8A7A5E-D425-40EC-B40A-7DA21BA1866F@fb.com> References: <20190529212049.2413886-1-songliubraving@fb.com> <20190529212049.2413886-5-songliubraving@fb.com> <20190530122055.xzlbo3wfpqtmo2fw@box> In-Reply-To: <20190530122055.xzlbo3wfpqtmo2fw@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:c090:200::3:bc80] x-ms-publictraffictype: Email x-ms-office365-filtering-correlation-id: 87e47887-e2ce-48d5-6d68-08d6e523f91f x-microsoft-antispam: BCL:0;PCL:0;RULEID:(2390118)(7020095)(4652040)(8989299)(5600148)(711020)(4605104)(1401327)(4534185)(4627221)(201703031133081)(201702281549075)(8990200)(2017052603328)(7193020);SRVR:BN6PR15MB1857; x-ms-traffictypediagnostic: BN6PR15MB1857: x-microsoft-antispam-prvs: x-ms-oob-tlc-oobclassifiers: OLM:6790; x-forefront-prvs: 00531FAC2C x-forefront-antispam-report: SFV:NSPM;SFS:(10019020)(136003)(396003)(346002)(39860400002)(376002)(366004)(189003)(199004)(64756008)(50226002)(46003)(81166006)(66446008)(4744005)(316002)(6506007)(53936002)(6246003)(14454004)(6512007)(8676002)(478600001)(4326008)(2906002)(91956017)(73956011)(66476007)(76116006)(66556008)(5660300002)(305945005)(7736002)(6116002)(25786009)(66946007)(14444005)(476003)(68736007)(71190400001)(54906003)(86362001)(99286004)(71200400001)(83716004)(229853002)(446003)(2616005)(53546011)(11346002)(256004)(6916009)(8936002)(486006)(102836004)(76176011)(33656002)(36756003)(57306001)(6486002)(81156014)(186003)(6436002)(7416002)(82746002);DIR:OUT;SFP:1102;SCL:1;SRVR:BN6PR15MB1857;H:BN6PR15MB1154.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: cg38ktuGDSdnLQFnRRwOCu9VhGBUi85YIRwrbqiVzceEdEX+l+3ZTiWgOFb4Z2uyN5snafUqSPH0LzJIOj+rhttcHeobAYED0k+AqOqpM4oADMZSclCZvCSuFHJiaEzxH4TJLC3jdJEWZB5996OslEDQUYEy4vbKM9DHzUrGwUTOZX9oRiywyLHkQGkFVrkN0wZgvKHsYVxePRyHu9gLFmAv2MdA9ieJrLJZyS4ruHTk25nt1tmjeoL/mDcP7jLv6GgVAvlN8ej4pLQFAST0DdCNnBfn1Qi0ptdu0RskSmUzGZDG54cAFEaMFdoFFsWpT/tyZ1L8CQq1dhlD4xWHwJFHxu4mOgnUXK05a70DJrdgE7L5BcoKArWYVnAM6lVgxigCkaPuXuKIpX27j2+2RSZFk4Es7ulatm/rIfgWah0= Content-Type: text/plain; charset="us-ascii" Content-ID: <717A3B52E0DEBB468BE5462786ACC0C7@namprd15.prod.outlook.com> Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-MS-Exchange-CrossTenant-Network-Message-Id: 87e47887-e2ce-48d5-6d68-08d6e523f91f X-MS-Exchange-CrossTenant-originalarrivaltime: 30 May 2019 17:26:38.2213 (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: BN6PR15MB1857 X-OriginatorOrg: fb.com X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-05-30_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=659 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1905300122 X-FB-Internal: deliver Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > On May 30, 2019, at 5:20 AM, Kirill A. Shutemov wr= ote: >=20 > On Wed, May 29, 2019 at 02:20:49PM -0700, Song Liu wrote: >> After all uprobes are removed from the huge page (with PTE pgtable), it >> is possible to collapse the pmd and benefit from THP again. This patch >> does the collapse. >=20 > I don't think it's right way to go. We should deferred it to khugepaged. > We need to teach khugepaged to deal with PTE-mapped compound page. > And uprobe should only kick khugepaged for a VMA. Maybe synchronously. >=20 I guess that would be the same logic, but run in khugepaged? It doesn't have to be done synchronously.=20 Let me try that Thanks, Song > --=20 > Kirill A. Shutemov