From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751442AbWBQO11 (ORCPT ); Fri, 17 Feb 2006 09:27:27 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751446AbWBQO11 (ORCPT ); Fri, 17 Feb 2006 09:27:27 -0500 Received: from mail03.syd.optusnet.com.au ([211.29.132.184]:51675 "EHLO mail03.syd.optusnet.com.au") by vger.kernel.org with ESMTP id S1751442AbWBQO10 (ORCPT ); Fri, 17 Feb 2006 09:27:26 -0500 From: Con Kolivas To: Kevin Radloff Subject: Re: [ck] [PATCH] mm: implement swap prefetching (v26) Date: Sat, 18 Feb 2006 01:26:57 +1100 User-Agent: KMail/1.9.1 Cc: Andrew Morton , ck list , linux kernel mailing list , Bart Samwel References: <200602172235.40019.kernel@kolivas.org> <3b0ffc1f0602170618u7a1ad877s337de33c0a8f44f9@mail.gmail.com> In-Reply-To: <3b0ffc1f0602170618u7a1ad877s337de33c0a8f44f9@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200602180126.58519.kernel@kolivas.org> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Saturday 18 February 2006 01:18, Kevin Radloff wrote: > On 2/17/06, Con Kolivas wrote: > > Added disabling of swap prefetching when laptop_mode is enabled. > > Why bother with this? As someone commented in a previous thread, > wouldn't it be better to let the laptop_mode script handle it? The discussion was about what size to make the swap prefetching. Since the size is not user tunable any more that is not the case. I had an offlist discussion with Bart Samwel about it and basically if your drive spins down at 5 seconds (which is what commonly happens with laptop mode) you will never have an opportunity to prefetch. This means swap prefetch will basically always spin up the drive nullifying laptop mode. On balance if you care about power more than anything to actually set laptop mode I suspect you wont want prefetch using any more power. Cheers, Con