Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S268534AbUI3CkP (ORCPT ); Wed, 29 Sep 2004 22:40:15 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S268609AbUI3CkO (ORCPT ); Wed, 29 Sep 2004 22:40:14 -0400 Received: from fw.osdl.org ([65.172.181.6]:8362 "EHLO mail.osdl.org") by vger.kernel.org with ESMTP id S268534AbUI3CkL (ORCPT ); Wed, 29 Sep 2004 22:40:11 -0400 Date: Wed, 29 Sep 2004 22:29:38 -0700 From: Andrew Morton To: Ram Pai Cc: adilger@clusterfs.com, slpratt@austin.ibm.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH/RFC] Simplified Readahead Message-Id: <20040929222938.47d2f976.akpm@osdl.org> In-Reply-To: <1096511206.5481.58.camel@dyn319181.beaverton.ibm.com> References: <415B3845.3010005@austin.ibm.com> <20040929231327.GM2061@schnapps.adilger.int> <1096511206.5481.58.camel@dyn319181.beaverton.ibm.com> X-Mailer: Sylpheed version 0.9.4 (GTK+ 1.2.10; i686-pc-linux-gnu) Mime-Version: 1.0 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: 879 Lines: 18 Ram Pai wrote: > > On Wed, 2004-09-29 at 16:13, Andreas Dilger wrote: > > On a readahead-related note, I'm wondering how hard it would be to have > > some tunables and/or hooks from the readahead state manchine made > > available to the filesystem? With the 2.4 readahead code it was basically > > impossible for the filesystem to disable the readahead, I haven't looked > > at the 2.6 readahead enough to determine whether we need that or not. > > > The best way currently to shutoff readahead is to poke into the file > descriptors' readahead structure and set ra_pages to 0. fadvise(fd, POSIX_FADV_RANDOM). - 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/