From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 25 Feb 2003 10:20:53 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 25 Feb 2003 10:20:53 -0500 Received: from [195.223.140.107] ([195.223.140.107]:48006 "EHLO athlon.random") by vger.kernel.org with ESMTP id ; Tue, 25 Feb 2003 10:20:51 -0500 Date: Tue, 25 Feb 2003 16:32:13 +0100 From: Andrea Arcangeli To: Dejan Muhamedagic Cc: linux-kernel@vger.kernel.org Subject: Re: vm issues (2) Message-ID: <20030225153213.GI29467@dualathlon.random> References: <20030225131328.A8651@smp.colors.kwc> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20030225131328.A8651@smp.colors.kwc> User-Agent: Mutt/1.4i X-GPG-Key: 1024D/68B9CB43 X-PGP-Key: 1024R/CB4660B9 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Feb 25, 2003 at 01:13:28PM +0100, Dejan Muhamedagic wrote: > Hello, > > The new kernel 2.4.21-pre4aa3 is running now, but the box behaves > similarly. It still swaps quite a lot and much more than the rmap > vm. Both servers are under the same load. > > One difference is the amount of free memory: > > r b w swpd free buff cache si so bi bo in cs us sy id > aa: > 0 7 0 5773620 202416 118076 2069716 5330 746 5330 766 4845 5597 12 14 74 > rmap: > 0 0 0 3498044 13572 4144 4754596 74 0 75 6 642 598 5 3 92 > > The aa kernel keeps ~200MB out of 6GB of memory unused. I'm not > sure, but if we could reduce it perhaps there would be much less > swapping. Is there a way to achieve this? that is a feature, it guarantees highmem unfreeable allocations like pagetables can't eat all your normal zone. You can reduce the 200MB with this boot command: lower_zone_reserve=256,256 As to decrease the swapping I just told you how to do that tweaking vm_mapped_ratio. > > Another notable difference between the two vm versions is that the > rmap vm maintains about 80% of memory on the active list and the > aa vm much less: between 4% and 12%. The rmap vm must use more > CPU, but these servers have a lot of processing power so it is not > noticeable. the theory was that rmap would reduce the cpu utilization but of course the patch don't do juts rmap. Andrea