Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Mon, 26 Nov 2001 18:27:58 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Mon, 26 Nov 2001 18:27:49 -0500 Received: from mout1.freenet.de ([194.97.50.132]:17843 "EHLO mout1.freenet.de") by vger.kernel.org with ESMTP id ; Mon, 26 Nov 2001 18:27:35 -0500 Date: Tue, 27 Nov 2001 00:25:25 +0100 To: Andrew Morton Cc: Oliver Xymoron , linux-kernel Subject: Re: ext3: kjournald and spun-down disks Message-ID: <20011127002525.A2912@pelks01.extern.uni-tuebingen.de> Mail-Followup-To: Andrew Morton , Oliver Xymoron , linux-kernel In-Reply-To: <3BFEF71A.F32176FE@zip.com.au> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.1.12i In-Reply-To: <3BFEF71A.F32176FE@zip.com.au>; from akpm@zip.com.au on Fri, Nov 23, 2001 at 05:25:46PM -0800 From: Daniel Kobras Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org 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. > Tell me if this is joyful: [...] > - transaction->t_expires = jiffies + journal->j_commit_interval; > + transaction->t_expires = jiffies + dirty_buffer_flush_interval(); This change doesn't take care of kupdated's most interesting feature, i.e. that you can entirely stop it (with a flush interval of zero and/or a SIGSTOP). Now, if kjournald honoured SIGSTOP/SIGCONT, I could teach noflushd to handle the spindown issue in userland. Uh, at least for one small detail: Is there a way to tell which kjournald process is associated to which partition? A fake cmdline, or an fd to the partition's device node that shows up in /proc//fd would indeed be quite helpful. Regards, Daniel. - 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/