From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1946064AbWGOPEU (ORCPT ); Sat, 15 Jul 2006 11:04:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1946065AbWGOPEU (ORCPT ); Sat, 15 Jul 2006 11:04:20 -0400 Received: from 142.163.233.220.exetel.com.au ([220.233.163.142]:23735 "EHLO idefix.homelinux.org") by vger.kernel.org with ESMTP id S1946060AbWGOPET (ORCPT ); Sat, 15 Jul 2006 11:04:19 -0400 Subject: Re: Where is RLIMIT_RT_CPU? From: Jean-Marc Valin To: Arjan van de Ven Cc: Lee Revell , Esben Nielsen , linux-kernel@vger.kernel.org, Ingo Molnar In-Reply-To: <1152974578.3114.24.camel@laptopd505.fenrus.org> References: <1152663825.27958.5.camel@localhost> <1152809039.8237.48.camel@mindpipe> <1152869952.6374.8.camel@idefix.homelinux.org> <1152919240.6374.38.camel@idefix.homelinux.org> <1152971896.16617.4.camel@mindpipe> <1152973159.6374.59.camel@idefix.homelinux.org> <1152974578.3114.24.camel@laptopd505.fenrus.org> Content-Type: text/plain Content-Transfer-Encoding: 7bit Organization: =?ISO-8859-1?Q?Universit=E9?= de Sherbrooke Date: Sun, 16 Jul 2006 01:04:17 +1000 Message-Id: <1152975857.6374.65.camel@idefix.homelinux.org> Mime-Version: 1.0 X-Mailer: Evolution 2.6.1 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > as long as you can fork and exec as many of those processes as you want > a per process rlimit is useless security wise... an evil user just fires > off a second process just before the first one gets killed and a non-RT > root still is starved out. Of course, which is why the idea is for the limit to be global, across all non-root users. AFAIK, that's what Ingo's original (pre-2.6.12) patch did and also what Con Kolivas' SCHED_ISO patch does. That's also why I think it would be very hard (if possible at all) to do this in user space. Jean-Marc