From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932150AbWAULmM (ORCPT ); Sat, 21 Jan 2006 06:42:12 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932152AbWAULmM (ORCPT ); Sat, 21 Jan 2006 06:42:12 -0500 Received: from ns.virtualhost.dk ([195.184.98.160]:8559 "EHLO virtualhost.dk") by vger.kernel.org with ESMTP id S932150AbWAULmL (ORCPT ); Sat, 21 Jan 2006 06:42:11 -0500 Date: Sat, 21 Jan 2006 12:44:08 +0100 From: Jens Axboe To: Tejun Heo Cc: Chuck Ebbert <76306.1226@compuserve.com>, Andrew Morton , linux-kernel , Mingming Cao Subject: Re: Fall back io scheduler for 2.6.15? Message-ID: <20060121114408.GS13429@suse.de> References: <200601141113_MC3-1-B5DA-F6EC@compuserve.com> <20060116084336.GO3945@suse.de> <43D1D134.5070401@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <43D1D134.5070401@gmail.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Jan 21 2006, Tejun Heo wrote: > Jens Axboe wrote: > >On Sat, Jan 14 2006, Chuck Ebbert wrote: > > > >>In-Reply-To: <20060113174914.7907bf2c.akpm@osdl.org> > >> > >>On Fri, 13 Jan 2006, Andrew Morton wrote: > >> > >> > >>>OK. And I assume that AS wasn't compiled, so that's why it fell back? > >> > >>As of 2.6.15 you need to use "anticipatory" instead of "as". > >> > >>Maybe this patch would help? > >> > >>Signed-off-by: Chuck Ebbert <76306.1226@compuserve.com> > >> > >>--- 2.6.15a.orig/block/elevator.c > >>+++ 2.6.15a/block/elevator.c > >>@@ -150,6 +150,13 @@ static void elevator_setup_default(void) > >> if (!chosen_elevator[0]) > >> strcpy(chosen_elevator, CONFIG_DEFAULT_IOSCHED); > >> > >>+ /* > >>+ * Be backwards-compatible with previous kernels, so users > >>+ * won't get the wrong elevator. > >>+ */ > >>+ if (!strcmp(chosen_elevator, "as")) > >>+ strcpy(chosen_elevator, "anticipatory"); > >>+ > >> /* > >> * If the given scheduler is not available, fall back to no-op. > >> */ > > > > > >We probably should apply this, since it used to be 'as'. > > > > Just out of curiousity, why did 'as' get renamed to 'anticipatory'? Side effect really, not intentional. 'as' always registered itself with the elevator core as "anticipatory", the logic to match elevator=foo string to scheduler used to be completely seperate prior to the addition of online switchable elevators. So when those two were tied together, the "as" disappeared. I guess the right thing to do at that time was to rename "anticipatory", but that didn't happen... -- Jens Axboe