From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752060AbWCKHun (ORCPT ); Sat, 11 Mar 2006 02:50:43 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752068AbWCKHun (ORCPT ); Sat, 11 Mar 2006 02:50:43 -0500 Received: from mail.gmx.net ([213.165.64.20]:21160 "HELO mail.gmx.net") by vger.kernel.org with SMTP id S1752060AbWCKHum (ORCPT ); Sat, 11 Mar 2006 02:50:42 -0500 X-Authenticated: #14349625 Subject: Re: [PATCH] mm: Implement swap prefetching tweaks From: Mike Galbraith To: Con Kolivas Cc: Andrew Morton , linux-kernel@vger.kernel.org, ck@vds.kolivas.org In-Reply-To: <200603111824.06274.kernel@kolivas.org> References: <200603102054.20077.kernel@kolivas.org> <200603111650.23727.kernel@kolivas.org> <1142056851.7819.54.camel@homer> <200603111824.06274.kernel@kolivas.org> Content-Type: text/plain Date: Sat, 11 Mar 2006 08:51:39 +0100 Message-Id: <1142063500.7605.13.camel@homer> Mime-Version: 1.0 X-Mailer: Evolution 2.4.0 Content-Transfer-Encoding: 7bit X-Y-GMX-Trusted: 0 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 2006-03-11 at 18:24 +1100, Con Kolivas wrote: > On Saturday 11 March 2006 17:00, Mike Galbraith wrote: > > If you're creating a lot of traffic, I can see it causing problems. I > > was under the impression that you were doing minimal IO and absolutely > > trivial CPU. That's what didn't make sense to me to be clear. > > A lot of cpu would be easier to handle; it's using absolutely miniscule > amounts of cpu. The IO is massive though (and seeky in nature), and reading > from a swap partition seems particularly expensive in this regard. There used to be a pages in flight 'restrictor plate' in there that would have probably helped this situation at least a little. But in any case, it sounds like you'll have to find a way to submit the IO in itty bitty synchronous pieces. -Mike