Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1763812AbYBZTbd (ORCPT ); Tue, 26 Feb 2008 14:31:33 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1761831AbYBZTbY (ORCPT ); Tue, 26 Feb 2008 14:31:24 -0500 Received: from x35.xmailserver.org ([64.71.152.41]:41755 "EHLO x35.xmailserver.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761691AbYBZTbX (ORCPT ); Tue, 26 Feb 2008 14:31:23 -0500 X-AuthUser: davidel@xmailserver.org Date: Tue, 26 Feb 2008 11:31:21 -0800 (PST) From: Davide Libenzi X-X-Sender: davide@alien.or.mcafeemobile.com To: Michael Kerrisk cc: Pierre Habouzit , lkml , Eric Dumazet , Marc Lehmann , David Schwartz Subject: Re: epoll and shared fd's In-Reply-To: Message-ID: References: <20080118134318.GD9607@artemis.madism.org> <20080124084001.GB7356@artemis.madism.org> <517f3f820801252337lcd4b0a0hde7359dc46a947dd@mail.gmail.com> <47C42CB3.8040500@gmail.com> X-GPG-FINGRPRINT: CFAE 5BEE FD36 F65E E640 56FE 0974 BF23 270F 474E X-GPG-PUBLIC_KEY: http://www.xmailserver.org/davidel.asc MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1450 Lines: 37 On Tue, 26 Feb 2008, Michael Kerrisk wrote: > Okay -- I'll look at it some more. I am however loathe to drop the > term open file description, because POSIX uses, as well as a number of > other Linux man pages by now. Heh, POSIX. Now doesn't take a genius to see that "file description" and "file descriptor" looks amazingly similar, does it? :) > > That'd mean placing an eventpoll custom hook into sys_close(). Looks > > very bad to me, and probably will look even worse to other kernel > > folks. Is not much a performance issue (a check to see if a file* is > > an eventpoll file is as easy as comparing the f_op pointer), but a > > design/style issue. > > Oh -- I wasn't suggesting we could make the change now -- it would > break the ABI and all that. I was just wondering why the decision > wasn't made to do it the other way to begin with. The existing > semantics are somewhat couterintuitive, and potentially interact > libraries that do private manipulations with file descriptors. For the same reason that a custom hook in sys_close wouldn't have passed the radar ;) As far as problems with libraries doing tricks with fds, that's an issue that goes beyond epoll. - Davide -- 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/