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[209.132.180.67]) by mx.google.com with ESMTP id z21si1482556oti.160.2019.12.10.02.22.23; Tue, 10 Dec 2019 02:22:37 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727211AbfLJKVx (ORCPT + 99 others); Tue, 10 Dec 2019 05:21:53 -0500 Received: from eu-smtp-delivery-151.mimecast.com ([146.101.78.151]:57111 "EHLO eu-smtp-delivery-151.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726574AbfLJKVx (ORCPT ); Tue, 10 Dec 2019 05:21:53 -0500 Received: from AcuMS.aculab.com (156.67.243.126 [156.67.243.126]) (Using TLS) by relay.mimecast.com with ESMTP id uk-mta-181-dlX51XbcOgGmzaLpZVEObQ-1; Tue, 10 Dec 2019 10:21:50 +0000 Received: from AcuMS.Aculab.com (fd9f:af1c:a25b:0:43c:695e:880f:8750) by AcuMS.aculab.com (fd9f:af1c:a25b:0:43c:695e:880f:8750) with Microsoft SMTP Server (TLS) id 15.0.1347.2; Tue, 10 Dec 2019 10:21:49 +0000 Received: from AcuMS.Aculab.com ([fe80::43c:695e:880f:8750]) by AcuMS.aculab.com ([fe80::43c:695e:880f:8750%12]) with mapi id 15.00.1347.000; Tue, 10 Dec 2019 10:21:49 +0000 From: David Laight To: 'Andy Lutomirski' CC: Eric Dumazet , network dev , "x86@kernel.org" , "linux-kernel@vger.kernel.org" Subject: RE: recvfrom/recvmsg performance and CONFIG_HARDENED_USERCOPY Thread-Topic: recvfrom/recvmsg performance and CONFIG_HARDENED_USERCOPY Thread-Index: AdWsNynavvs+VRwOQ6mSStk+IzVA6AACUqqAAI3fO8AAEiVBgAAgNCaQ Date: Tue, 10 Dec 2019 10:21:49 +0000 Message-ID: <5a3cf731da8442909a4b84d975beb5e0@AcuMS.aculab.com> References: In-Reply-To: Accept-Language: en-GB, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.202.205.107] MIME-Version: 1.0 X-MC-Unique: dlX51XbcOgGmzaLpZVEObQ-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: base64 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org RnJvbTogQW5keSBMdXRvbWlyc2tpDQo+IFNlbnQ6IDA5IERlY2VtYmVyIDIwMTkgMTg6NDMNCj4g DQo+ID4gT24gRGVjIDksIDIwMTksIGF0IDM6MDEgQU0sIERhdmlkIExhaWdodCA8RGF2aWQuTGFp Z2h0QGFjdWxhYi5jb20+IHdyb3RlOg0KPiA+DQo+ID4g77u/RnJvbTogRXJpYyBEdW1hemV0DQo+ ID4+IFNlbnQ6IDA2IERlY2VtYmVyIDIwMTkgMTQ6MjINCj4gPiAuLi4NCj4gPj4gUmVhbCBxdWVz dGlvbiBpcyA6IERvIHlvdSBhY3R1YWxseSBuZWVkIHRvIHVzZSByZWN2bXNnKCkgaW5zdGVhZCBv ZiByZWN2ZnJvbSgpID8NCj4gPj4gSWYgcmVjdm1zZygpIHByb3ZpZGVzIGFkZGl0aW9uYWwgY21z ZywgdGhpcyBpcyBub3Qgc3VycHJpc2luZyBpdCBpcyBtb3JlIGV4cGVuc2l2ZS4NCj4gPg0KPiA+ IEV4Y2VwdCBJJ20gbm90IHBhc3NpbmcgaW4gYSBidWZmZXIgZm9yIGl0Lg0KPiA+IFRoZSByZWFz b24gSSdtIGxvb2tpbmcgYXQgcmVjdm1zZyBpcyB0aGF0IEknZCBsaWtlIHRvIHVzZSByZWN2bW1z ZyBpdCBvcmRlciB0bw0KPiA+IHJlYWQgb3V0IG1vcmUgdGhhbiBvbmUgbWVzc2FnZSBmcm9tIGEg c29ja2V0IHdpdGhvdXQgZG9pbmcgYW4gZXh0cmEgcG9sbCgpLg0KPiA+IE5vdGUgdGhhdCBJIGRv bid0IGV4cGVjdCB0aGVyZSB0byBiZSBhIHNlY29uZCBtZXNzYWdlIG1vc3Qgb2YgdGhlIHRpbWUg YW5kDQo+ID4gYWxtb3N0IG5ldmVyIGEgdGhpcmQgb25lLg0KPiA+DQo+ID4gQWx0aG91Z2ggSSB0 aGluayB0aGF0IHdpbGwgb25seSBldmVyICd3aW4nIGlmIHJlY3ZtbXNnKCkgY2FsbGVkIHZmc19w b2xsKCkgdG8gZmluZA0KPiA+IGlmIHRoZXJlIHdhcyBtb3JlIGRhdGEgdG8gcmVhZCBiZWZvcmUg ZG9pbmcgYW55IG9mIHRoZSBjb3B5X2Zyb21fdXNlcigpIGV0Yw0KPiANCj4gSSB3b3VsZCBzdWdn ZXN0IGEgbW9yZSBnZW5lcmFsIGltcHJvdmVtZW50OiBhZGQgYSAtRUFHQUlOIGZhc3QgcGF0aCB0 byByZWN2bXNnKCkuDQo+IElmIHRoZSBzb2NrZXQgaXMgbm9uYmxvY2tpbmcgYW5kIGhhcyBubyBk YXRhIHRvDQo+IHJlYWQsIHRoZW4gdGhlcmUgc2hvdWxkbuKAmXQgYmUgYSBuZWVkIHRvIHByb2Nl c3MgdGhlIGlvdmVjIGF0IGFsbC4NCg0KWW91IGRvbid0IHdhbnQgdG8gZG8gdGhhdCBmb3IgcmVj dm1zZygpIGl0c2VsZi4NCkl0IHdpbGwgbm9ybWFsbHkgb25seSBiZSBjYWxsZWQgaWYgcG9sbCgp IHJlcG9ydGVkIGRhdGEgaXMgYXZhaWxhYmxlLg0KQWN0dWFsbHkgdGhlIE1TR19XQUlURk9ST05F IGZsYWcgY291bGQgYmUgdXNlZCB0byBkbyBhIGNhbGwNCnRvIHZmc19wb2xsKCkgYmVmb3JlIHRo ZSBzdWJzZXF1ZW50IGNhbGxzIHRvIF9fc3lzX3JlY3Ztc2coKS4NClRoaXMgd2lsbCB3b3JrIGZv ciBub24tYmxvY2tpbmcgc29ja2V0cyAob3IgZXZlbiBjYWxscyB3aXRoIGJvdGgNCk1TR19ET05U V0FJVCBhbmQgTVNHX1dBSVRGT1JPTkUgc2V0KS4NCg0KCURhdmlkDQoNCi0NClJlZ2lzdGVyZWQg QWRkcmVzcyBMYWtlc2lkZSwgQnJhbWxleSBSb2FkLCBNb3VudCBGYXJtLCBNaWx0b24gS2V5bmVz LCBNSzEgMVBULCBVSw0KUmVnaXN0cmF0aW9uIE5vOiAxMzk3Mzg2IChXYWxlcykNCg==