From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262978AbUBZUT4 (ORCPT ); Thu, 26 Feb 2004 15:19:56 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262838AbUBZUSp (ORCPT ); Thu, 26 Feb 2004 15:18:45 -0500 Received: from alt.aurema.com ([203.217.18.57]:65212 "EHLO smtp.sw.oz.au") by vger.kernel.org with ESMTP id S262978AbUBZUPo (ORCPT ); Thu, 26 Feb 2004 15:15:44 -0500 Message-ID: <403E53EA.2010001@aurema.com> Date: Fri, 27 Feb 2004 07:15:38 +1100 From: Peter Williams Organization: Aurema Pty Ltd User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.4) Gecko/20030624 Netscape/7.1 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Timothy Miller CC: linux-kernel@vger.kernel.org Subject: Re: [RFC][PATCH] O(1) Entitlement Based Scheduler References: <403D3E47.4080501@techsource.com> <403D576A.6030900@aurema.com> <403E1A11.5050704@techsource.com> In-Reply-To: <403E1A11.5050704@techsource.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Timothy Miller wrote: > > > Peter Williams wrote: > >> Timothy Miller wrote: >> > >> >>> In fact, that may be the only "flaw" in your design. It sounds like >>> your scheduler does an excellent job at fairness with very low >>> overhead. The only problem with it is that it doesn't determine >>> priority dynamically. >> >> >> >> This (i.e. automatic renicing of specified programs) is a good idea >> but is not really a function that should be undertaken by the >> scheduler itself. Two possible solutions spring to mind: >> >> 1. modify the do_execve() in fs/exec.c to renice tasks when they >> execute specified binaries > > > We don't want user-space programs to have control over priority. They already do e.g. renice is such a program. > This > is DoS waiting to happen. > >> 2. have a user space daemon poll running tasks periodically and renice >> them if they are running specified binaries > > > This is much too specific. Again, if the USER has control over this > list, It would obviously be under root control. > then it's potential DoS. And if the user adds a program which > should qualify but which is not in the list, the program will not get > its deserved boost. > > And a sysadmin is not going to want to update 200 lab computers just so > one user can get their program to run properly. > >> >> Both of these solutions have their advantages and disadvantages, are >> (obviously) complicated than I've made them sound and would require a >> great deal of care to be taken during their implementation. However, >> I think that they are both doable. My personal preference would be >> for the in kernel solution on the grounds of efficiency. > > > They are doable, but they are not a general solution. > Peter -- Dr Peter Williams, Chief Scientist peterw@aurema.com Aurema Pty Limited Tel:+61 2 9698 2322 PO Box 305, Strawberry Hills NSW 2012, Australia Fax:+61 2 9699 9174 79 Myrtle Street, Chippendale NSW 2008, Australia http://www.aurema.com