From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263205AbUB1FCS (ORCPT ); Sat, 28 Feb 2004 00:02:18 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263198AbUB1FCS (ORCPT ); Sat, 28 Feb 2004 00:02:18 -0500 Received: from alt.aurema.com ([203.217.18.57]:11154 "EHLO smtp.sw.oz.au") by vger.kernel.org with ESMTP id S263205AbUB1FCF (ORCPT ); Sat, 28 Feb 2004 00:02:05 -0500 Message-ID: <4040207E.8040706@aurema.com> Date: Sat, 28 Feb 2004 16:00:46 +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> <403E53EA.2010001@aurema.com> <403F582E.10500@techsource.com> In-Reply-To: <403F582E.10500@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: >> > >>> >>> >>> We don't want user-space programs to have control over priority. >> >> >> >> They already do e.g. renice is such a program. > > > No one's talking about LOWERING priority here. You can only DoS someone > else if you can set negative nice values, and non-root can't do that. Which is why root has to be in control of the mechanism. > >> >>> 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. > > > And that means if someone wants to run a program which is not on the > list but which requires (and deserves) higher priority, they cannot. Any mechanism that causes a task to be treated more favourably than others needs to be under root's control. It's root's prerogative to decide who deserves more favourable treatment. This is even more important (for obvious reasons) if a reservation (or guarantee) mechanism is involved. I'd like to stress at this point that xmms only needs a boost under extremely high loads and this issue is being blown out of proportion. 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