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x-originating-ip: [103.140.231.58] x-ms-publictraffictype: Email x-ms-office365-filtering-correlation-id: b3f2f1c1-d45c-446e-6f81-08d7e099fab7 x-ms-traffictypediagnostic: SG2PR04MB3721:|SG2PR04MB3721: x-ms-exchange-transport-forked: True x-microsoft-antispam-prvs: x-ms-oob-tlc-oobclassifiers: OLM:9508; x-forefront-prvs: 0373D94D15 x-forefront-antispam-report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:SG2PR04MB2921.apcprd04.prod.outlook.com;PTR:;CAT:NONE;SFTY:;SFS:(10019020)(4636009)(366004)(55016002)(64756008)(52536014)(26005)(9686003)(44832011)(107886003)(71200400001)(7696005)(4326008)(86362001)(66446008)(66556008)(66946007)(81156014)(2906002)(5660300002)(186003)(54906003)(6916009)(4744005)(66476007)(76116006)(33656002)(8936002)(6506007)(498600001)(8676002);DIR:OUT;SFP:1102; received-spf: None (protection.outlook.com: oneplus.com does not designate permitted sender hosts) x-ms-exchange-senderadcheck: 1 x-microsoft-antispam: BCL:0; x-microsoft-antispam-message-info: JmcRYNfaRcBh/UvHNHuAE/4vjXpE8DLD1QXSMSOAMD1+1RTVKuQdtkBBECWdMj+xyN8rYPF6gO9Vs/OI8HkpYJH3MxtVTt8KWPUSc4vD/tFZz6P5teHZF04eZVQAbkFtYmzzbO+wcgKvRwhTcDgFXbUrxJhGabxjjnnWC3iRK4h04sbRcAgKyMG18Orcq9pOtprOU6CwFD4R/wOG5pNeJgB65GLF1Wdqt1nBfw5oQSuEVa//t01g7X5PY0KeDsCVFiT5zj9r1WCWrPOf2BcCZnFqUawA8pZFaaSIo8gEZJJPXhP2i0nWdM6rvGGYQw+pSemTjD8GS5t+rIgTPMncMgQHmhTsCUYRciiSwMzzQOuGXpix8z35eWUkkFrrmZ3Lb4rysg6DyJu0ST2uDZSmHDd/MuNd6FvNRXNAAdPM910jsVOMHVXCFc8KS+NsrGWw x-ms-exchange-antispam-messagedata: MWOymUVOKoZ0Xab6yNzYI0BCC3uBMsPpDp5sz59ssGRktVn9Fa/YQHOMp/nlo9wRNJD3CcnYNe+ZnmXiMO5Oox45pZWiTKf2/CC/J+U7fGvSukNUzfJ8ahJGkhi6iMGLtGjjUog+kNyYyC/LU3brYg== Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-OriginatorOrg: oneplus.com X-MS-Exchange-CrossTenant-Network-Message-Id: b3f2f1c1-d45c-446e-6f81-08d7e099fab7 X-MS-Exchange-CrossTenant-originalarrivaltime: 14 Apr 2020 17:33:43.5119 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 0423909d-296c-463e-ab5c-e5853a518df8 X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: bSDw4Lt1scaWwtxAgJWxbBtbnwo7zvxlARMnFNmmbyy7ZMy1jq1rnEO0dYh9p1MnI8S1yShp0wrQHHzkD2H1bWpKEyQ/vrAqg2vqvs1x8ks= X-MS-Exchange-Transport-CrossTenantHeadersStamped: SG2PR04MB3721 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: > > > One interesting data point would be to see what the cost is for > > > breaking this up into a loop where you only process some fixed > > > number of pages and running it with cond_resched() so you can avoid > introducing latency spikes. > > > > As per the patch above, it's not using kmap_atomic() and hence > > preemption & page_fault are not disabled. Do we still need to explicitl= y call > cond_resched() in this case? > > #justAsking >=20 > Didn't see this answered on the list, but the answer is yes because the k= ernel > may not have CONFIG_PREEMPTION enabled. Ok. This is addressable. Prathu has already spin off v2. If at all there is= any scope for spinning v3, this would be taken care. Thanks for the clarification.