From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263379AbTDGLZC (for ); Mon, 7 Apr 2003 07:25:02 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263384AbTDGLZC (for ); Mon, 7 Apr 2003 07:25:02 -0400 Received: from werbeagentur-aufwind.com ([217.160.128.76]:10695 "EHLO mail.werbeagentur-aufwind.com") by vger.kernel.org with ESMTP id S263379AbTDGLZB (for ); Mon, 7 Apr 2003 07:25:01 -0400 Subject: Re: An idea for prefetching swapped memory... From: Christophe Saout To: linux-kernel@vger.kernel.org In-Reply-To: <200304072021.17080.kernel@kolivas.org> References: <200304071026.47557.schlicht@uni-mannheim.de> <200304072021.17080.kernel@kolivas.org> Content-Type: text/plain Organization: Message-Id: <1049715389.1096.7.camel@chtephan.cs.pocnet.net> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.3.1.99 (Preview Release) Date: 07 Apr 2003 13:36:29 +0200 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Am Mon, 2003-04-07 um 12.21 schrieb Con Kolivas: > > With this feature there should be no performance decrease because only free > > resources would be used, and if pages were swapped in but not be used, they > > stay not dirty and so have not to be written to disk when they are swapped > > out again. But the improvements should be obvious if simply the last swaped > > out pages are swapped in again... > > This has been argued before. Why would the last swapped out pages be the best > to swap in? The vm subsystem has (somehow) decided they're the least likely > to be used again so why swap them in? Are you sure this is working? When I'm watching a video ofer NFS on my machine which is idle (just X and mplayer, gnome in background, 256 MB of memory, 512 swap), after 30 minutes or so, the playback starts to jump. The cpu usage is below 10%, and it even does this when both X and mplayer are renice to -19 (!). So the VM swapped everything out and after 30 minutes it starts to swap out X oder mplayer itself, which is immediately swapped back in but the video jumps... :-( -- Christophe Saout