From mboxrd@z Thu Jan 1 00:00:00 1970 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 6A1B3C433FE for ; Wed, 9 Nov 2022 10:09:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229742AbiKIKJl convert rfc822-to-8bit (ORCPT ); Wed, 9 Nov 2022 05:09:41 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37770 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229526AbiKIKJk (ORCPT ); Wed, 9 Nov 2022 05:09:40 -0500 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 A7B4BBC93 for ; Wed, 9 Nov 2022 02:09:39 -0800 (PST) Received: from AcuMS.aculab.com (156.67.243.121 [156.67.243.121]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id uk-mta-81-ABe0gktTOTGcVfsSB0umYg-1; Wed, 09 Nov 2022 10:09:36 +0000 X-MC-Unique: ABe0gktTOTGcVfsSB0umYg-1 Received: from AcuMS.Aculab.com (10.202.163.6) by AcuMS.aculab.com (10.202.163.6) with Microsoft SMTP Server (TLS) id 15.0.1497.42; Wed, 9 Nov 2022 10:09:33 +0000 Received: from AcuMS.Aculab.com ([::1]) by AcuMS.aculab.com ([::1]) with mapi id 15.00.1497.042; Wed, 9 Nov 2022 10:09:33 +0000 From: David Laight To: 'Stefan Hajnoczi' , Jens Axboe CC: "linux-kernel@vger.kernel.org" , "netdev@vger.kernel.org" Subject: RE: [PATCHSET v3 0/5] Add support for epoll min_wait Thread-Topic: [PATCHSET v3 0/5] Add support for epoll min_wait Thread-Index: AQHY85bpT+hcAn2hREu69xxFvk5GCa42XVDw Date: Wed, 9 Nov 2022 10:09:33 +0000 Message-ID: References: <4281b354-d67d-2883-d966-a7816ed4f811@kernel.dk> <93fa2da5-c81a-d7f8-115c-511ed14dcdbb@kernel.dk> <75c8f5fe-6d5f-32a9-1417-818246126789@kernel.dk> 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: 8BIT Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Stefan Hajnoczi > Sent: 08 November 2022 17:24 ... > The way the current patches add min_wait into epoll_ctl() seems hacky to > me. struct epoll_event was meant for file descriptor event entries. It > won't necessarily be large enough for future extensions (luckily > min_wait only needs a uint64_t value). It's turning epoll_ctl() into an > ioctl()/setsockopt()-style interface, which is bad for anything that > needs to understand syscalls, like seccomp. A properly typed > epoll_wait3() seems cleaner to me. Is there any reason you can't use an ioctl() on an epoll fd? That would be cleaner that hacking at epoll_ctl(). It would also be easier to modify to allow (strange) things like: - return if no events for 10ms. - return 200us after the first event. - return after 10 events. - return at most 100 events. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)