Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753222AbaBCWG0 (ORCPT ); Mon, 3 Feb 2014 17:06:26 -0500 Received: from mail-ve0-f181.google.com ([209.85.128.181]:64015 "EHLO mail-ve0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750750AbaBCWGY (ORCPT ); Mon, 3 Feb 2014 17:06:24 -0500 MIME-Version: 1.0 In-Reply-To: <20140203215151.GA25594@dcvr.yhbt.net> References: <1391393832-8754-1-git-send-email-n1ght.4nd.d4y@gmail.com> <52EFEF0A.9080101@amacapital.net> <20140203215151.GA25594@dcvr.yhbt.net> From: Andy Lutomirski Date: Mon, 3 Feb 2014 14:06:04 -0800 Message-ID: Subject: Re: [RFC PATCH 0/3] epoll: read(),write(),ioctl() interface To: Eric Wong Cc: Nathaniel Yazdani , Al Viro , Linux FS Devel , "linux-kernel@vger.kernel.org" Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Feb 3, 2014 at 1:51 PM, Eric Wong wrote: > Andy Lutomirski wrote: >> >> On 02/02/2014 06:17 PM, Nathaniel Yazdani wrote: >> > So are you saying that those features you mentioned are specifically sought >> > after for the kernel? If so I'd like to take a crack at some of them, >> > may as well >> > get some use out of my new knowledge of epoll internals :) >> >> If by "sought after", you mean "is there at least one epoll user who >> wants them", then yes :) >> >> I think that EPOLLET and EPOLLONESHOT are giant hacks, and that what >> everyone really wants is the ability to very efficiently toggle events >> on and off. The ability to do it simultaneously and inexpensively >> with epoll_wait would make it happen. > > Everybody using single-threaded epoll, you mean? I suppose there's > quite a few of those. > > I've pondered an epoll_xchg syscall which would behave like *BSD kevent > to satisfy single-threaded users, but never got around to it. All my > epoll uses are multithreaded w/ oneshot nowadays, so xchg would only > save one syscall per thread. Even for multithreaded, the ability to rearm EPOLLONESHOT entries without extra syscalls would probably be useful. --Andy -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/