Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Mon, 26 Nov 2001 19:19:21 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Mon, 26 Nov 2001 19:19:12 -0500 Received: from waste.org ([209.173.204.2]:10184 "EHLO waste.org") by vger.kernel.org with ESMTP id ; Mon, 26 Nov 2001 19:18:58 -0500 Date: Mon, 26 Nov 2001 18:21:03 -0600 (CST) From: Oliver Xymoron To: Daniel Kobras cc: Andrew Morton , linux-kernel Subject: Re: ext3: kjournald and spun-down disks In-Reply-To: <20011127002525.A2912@pelks01.extern.uni-tuebingen.de> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 27 Nov 2001, Daniel Kobras wrote: > On Fri, Nov 23, 2001 at 05:25:46PM -0800, Andrew Morton wrote: > > Also, if we had appropriate hooks into the request layer, we could detect > > when the disk was being spun up for a read, and opporunistically flush > > out any pending writes. > > Actually you can't. SCSI spinup code isn't very useful anyway, and IDE disks > mostly handle spinup themselves. The kernel has too issue a reset to get a > disk back alive from sleep mode, but revival from standby doesn't involve > the kernel at all. When using the disk's internal timer, it isn't involved in > spindown either. Teaching the request layer about disk state might therefore > turn out to become rather messy, I suspect. Depends on how far you want to take it. The kernel can of course query to discover whether a device is on standby and delay writes if possible before actually initiating a flush. -- "Love the dolphins," she advised him. "Write by W.A.S.T.E.." - 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/