Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Mon, 18 Nov 2002 22:39:25 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Mon, 18 Nov 2002 22:39:25 -0500 Received: from mail.gmx.net ([213.165.64.20]:8587 "HELO mail.gmx.net") by vger.kernel.org with SMTP id ; Mon, 18 Nov 2002 22:39:24 -0500 Message-ID: <3DD9B3F8.DC291106@gmx.de> Date: Tue, 19 Nov 2002 04:46:00 +0100 From: Edgar Toernig MIME-Version: 1.0 To: Davide Libenzi CC: Linux Kernel Mailing List Subject: Re: [rfc] epoll interface change and glibc bits ... References: Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2117 Lines: 50 Davide Libenzi wrote: > > http://www.xmailserver.org/linux-patches/epoll.2 > http://www.xmailserver.org/linux-patches/epoll_create.2 > http://www.xmailserver.org/linux-patches/epoll_ctl.2 > http://www.xmailserver.org/linux-patches/epoll_wait.2 > > it is going to change though with the latest talks about the interface. My 2 cents: Remove the waitqueue stuff from epoll.2. It has meaning only to linux kernel developers and noone else. Please add more semantic details of the new facility. It is new and these man pages are the only (and normative) reference. I.e.: What about adding an fd twice to the epoll-set? Do you get an error, will it override the previous settings for that fd, will it be ignored, or is it registered twice and you get two results for that fd? Can two epoll-sets wait for the same fd? Are events reported to both epoll-fds? Is the epoll-fd itself poll/epoll/selectable? Can I build cluster of epoll-sets? What happens if the epollfd is put into its own fd set? Can I send the epoll-fd over a unix-socket to another process? Then, please add more details of how events are generated. You say, that an inactive-to-active transition causes an event. What is the starting point of the collection? (I guess, all transitions between two epoll_wait calls.) There could be a couple of transi- tions on an fd between two epoll_wait calls. Are these events com- bined into a single reported event or is each single edge reported? Does an operation on an fd effect the already collected but not yet reported events? About epoll_wait: it looks like a "read with timeout" call. Is that really necessary or wouldn't a normal read(2) work as well? Similar for epoll_ctl: couldn't a write(2) to the epoll-fd do the same? That are the things that come into my mind at the moment. I guess there are more details I've missed... Ciao, ET. - 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/