Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Mon, 28 Oct 2002 18:38:53 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Mon, 28 Oct 2002 18:38:52 -0500 Received: from mtao-m02.ehs.aol.com ([64.12.52.8]:60288 "EHLO mtao-m02.ehs.aol.com") by vger.kernel.org with ESMTP id ; Mon, 28 Oct 2002 18:38:51 -0500 Date: Mon, 28 Oct 2002 15:45:06 -0800 From: John Gardiner Myers Subject: Re: and nicer too - Re: [PATCH] epoll more scalable than poll In-reply-to: <20021028220809.GB27798@outpost.ds9a.nl> To: bert hubert Cc: Linux Kernel Mailing List , linux-aio@kvack.org, lse-tech@lists.sourceforge.net Message-id: <3DBDCC02.6060100@netscape.com> MIME-version: 1.0 Content-type: text/plain; charset=ISO-8859-1; format=flowed Content-transfer-encoding: 7BIT X-Accept-Language: en-us, en User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.2b) Gecko/20021016 References: <20021028220809.GB27798@outpost.ds9a.nl> <20021028225821.GA29868@outpost.ds9a.nl> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 748 Lines: 20 bert hubert wrote: >The interface is also lovely: > > The code you wrote has the standard epoll race condition. If the file descriptor 's' becomes readable before the call to sys_epoll_ctl, sys_epoll_wait() will never return the socket. The connection will hang and the file descriptor will effectively leak. As you have amply demonstrated, the current epoll API is error prone. The API should be fixed to test the poll condition and, if necessary, drop an event upon insertion to the set. - 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/