From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Mon, 24 Sep 2001 16:47:29 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Mon, 24 Sep 2001 16:47:20 -0400 Received: from mail.zmailer.org ([194.252.70.162]:55561 "EHLO zmailer.org") by vger.kernel.org with ESMTP id ; Mon, 24 Sep 2001 16:47:05 -0400 Date: Mon, 24 Sep 2001 23:47:17 +0300 From: Matti Aarnio To: "Eric W. Biederman" Cc: Simon Kirby , linux-kernel@vger.kernel.org Subject: Re: O_NONBLOCK on files Message-ID: <20010924234717.V11046@mea-ext.zmailer.org> In-Reply-To: <20010918234648.A21010@netnation.com> <20010919002439.A21138@netnation.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20010919002439.A21138@netnation.com>; from sim@netnation.com on Wed, Sep 19, 2001 at 12:24:39AM -0700 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Sep 19, 2001 at 12:24:39AM -0700, Simon Kirby wrote: > On Wed, Sep 19, 2001 at 01:05:06AM -0600, Eric W. Biederman wrote: > > What would cause the data to be read in if read just checks the caches? > > With sockets the other side is clearing pushing or pulling the data. With > > files there is no other side... > > Hmm...Without even thinking about it, I assumed it would start a read and > select() or poll() or some later call would return readable when my > outstanding request was fulfilled. But yes, I guess you're right, this is > different behavior because there is no other side. To push the idea into ultimate: AIO You open file, start IO, and do other things while the machine is doing IO. Doing open() asynchronously would be ultimate, but alas, not particularly trivial. There are problems also in the AIO status rendezvous mechanisms. Your best choice could be (with moderation) to do synchronous operations at separate threads. > Reading a file would need a receive queue to make this work, I guess. :) > Simon- > [ sim@stormix.com ][ sim@netnation.com ] /Matti Aarnio