Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 61F2DC61DA4 for ; Sat, 18 Mar 2023 12:41:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229599AbjCRMkK (ORCPT ); Sat, 18 Mar 2023 08:40:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55594 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229478AbjCRMkI (ORCPT ); Sat, 18 Mar 2023 08:40:08 -0400 Received: from eu-smtp-delivery-151.mimecast.com (eu-smtp-delivery-151.mimecast.com [185.58.86.151]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8494429426 for ; Sat, 18 Mar 2023 05:40:06 -0700 (PDT) Received: from AcuMS.aculab.com (156.67.243.121 [156.67.243.121]) by relay.mimecast.com with ESMTP with both STARTTLS and AUTH (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id uk-mta-275-lYTWO18YOr6zRMPC2d8q3w-1; Sat, 18 Mar 2023 12:40:03 +0000 X-MC-Unique: lYTWO18YOr6zRMPC2d8q3w-1 Received: from AcuMS.Aculab.com (10.202.163.6) by AcuMS.aculab.com (10.202.163.6) with Microsoft SMTP Server (TLS) id 15.0.1497.47; Sat, 18 Mar 2023 12:40:01 +0000 Received: from AcuMS.Aculab.com ([::1]) by AcuMS.aculab.com ([::1]) with mapi id 15.00.1497.047; Sat, 18 Mar 2023 12:40:01 +0000 From: David Laight To: 'richard clark' , Linus Torvalds CC: "linux-kernel@vger.kernel.org" Subject: RE: Question about select and poll system call Thread-Topic: Question about select and poll system call Thread-Index: AQHZWKoj15NaHXL3bku7XbgbJ/Iq0a8AePAA Date: Sat, 18 Mar 2023 12:40:01 +0000 Message-ID: <7a0033e7db3f4acb9d70b173d063b4d2@AcuMS.aculab.com> References: In-Reply-To: Accept-Language: en-GB, 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-Mimecast-Spam-Score: 0 X-Mimecast-Originator: aculab.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: base64 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org PiBPbiBGcmksIE1hciAxNywgMjAyMyBhdCAyOjE14oCvQU0gTGludXMgVG9ydmFsZHMNCj4gPHRv cnZhbGRzQGxpbnV4LWZvdW5kYXRpb24ub3JnPiB3cm90ZToNCj4gPg0KLi4uDQo+ID4gQW5kIGJh Y2sgdGhlbiwgd2UgaGFkIHRoaXM6DQo+ID4NCj4gPiAgIHR5cGVkZWYgdW5zaWduZWQgbG9uZyBm ZF9zZXQ7DQo+ID4NCj4gPiB3aGljaCBtYXkgc2VlbSBhIGJpdCBsaW1pdGluZyB0b2RheSAoIk9u bHkgMzIgYml0cz8/IT8iKSwgYnV0IHRvIHB1dA0KPiA+IHRoYXQgaW4gcGVyc3BlY3RpdmUsIGJh Y2sgdGhlbiB3ZSBhbHNvIGhhZCB0aGlzOg0KPiA+DQo+ID4gICAjZGVmaW5lIE5SX09QRU4gMjAN Cg0KVGhhdCBpcyB0aGUgaGlzdG9yaWMgbGltaXQgZm9yIFNZU1YgKGFuZCBwcm9iYWJseSBCU0Qp Lg0KSSBzdXNwZWN0IHlvdSBqdXN0IGNvcGllZCBpdC4NClF1aXRlIHdoeSBpdCB3YXMgMjAgYW5k IG5vdCAxNiBvciAzMiBJIGRvbid0IGtub3cuDQpCdXQgMjAgb3BlbiBmaWxlcyB3YXMgYXNzdW1l ZCB0byBiZSAncGxlbnR5JyENCg0KVGhlIGZpcnN0IFNZU1Yga2VybmVsIHRoYXQgc3VwcG9ydGVk IGZkID49IDIwIGFjdHVhbGx5IHVzZWQNCmEgbGlua2VkIGxpc3QgdG8gaG9sZCB0aGUgaW50ZXJu YWwgZGF0YSAobW9zdGx5IGEgcG9pbnRlcikuDQoNClNvIGFjY2Vzc2luZyBhIGJpZyBmZCBudW1i ZXIgd2FzIE8oZmQpLg0KQ2FsbGluZyBwb2xsKCkgTyhudW1mZCoqMikgYW5kIGdldHRpbmcgdGhh dCBtYW55IG9wZW4gc29ja2V0cw0KaW4gYSBuZXR3b3JrIHNlcnZlciBwcm9jZXNzIE8obioqMyku DQoNCkRvbid0IGV2ZW4gdGhpbmsgYWJvdXQgaG93IHNsb3dseSBhIHByb2Nlc3MgdHJ5aW5nIHRv DQp1c2UgMjAwMCBzb2NrZXRzIHdhcyENCg0KVGhlIDIwIGZkIGxpbWl0IGFsc28gbWFkZSB0aGVt IGEgbGltaXRlZCByZXNvdXJjZS4NCkRlbW9ucyBjb3VsZG4ndCByZWFsbHkgYWZmb3JkIHRvIGR1 cCgpIC9kZXYvbnVsbCBvbnRvIDAsIDEgYW5kIDIsDQppbnN0ZWFkIHRoZXknZCBqdXN0IGNsb3Nl IHRoZSBmZC4NCkFuIGFjY2lkZW50YWwgcHJpbnRmKCkgdGhhdCBzaG91bGQgaGF2ZSBiZWVuIHNw cmludGYoKSB0aGVuDQpzbG93bHkgZmlsbHMgdGhlIHN0ZG91dCBidWZmZXIsIHdoZW4gdGhhdCBl dmVudHVhbGx5IGZpbGxzDQp0aGUgd3JpdGUgdG8gZmQgMSBoYXMgc2lkZSBlZmZlY3RzIHRoYXQg YXJlIHJhdGhlciBkaWZmaWN1bHQNCnRvIGRlYnVnLg0KKFNvbWVvbmUgc2hvdWxkIGhhdmUgbm90 aWNlZCB0aGF0IHRoZSB0cmFjaW5nIHdhcyBpbmNvcnJlY3QpDQoNCglEYXZpZA0KDQotDQpSZWdp c3RlcmVkIEFkZHJlc3MgTGFrZXNpZGUsIEJyYW1sZXkgUm9hZCwgTW91bnQgRmFybSwgTWlsdG9u IEtleW5lcywgTUsxIDFQVCwgVUsNClJlZ2lzdHJhdGlvbiBObzogMTM5NzM4NiAoV2FsZXMpDQo=