From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1422742AbWGNUb3 (ORCPT ); Fri, 14 Jul 2006 16:31:29 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1161298AbWGNUb3 (ORCPT ); Fri, 14 Jul 2006 16:31:29 -0400 Received: from nf-out-0910.google.com ([64.233.182.188]:3832 "EHLO nf-out-0910.google.com") by vger.kernel.org with ESMTP id S1161292AbWGNUb2 (ORCPT ); Fri, 14 Jul 2006 16:31:28 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=googlemail.com; h=received:date:x-x-sender:to:cc:subject:in-reply-to:message-id:references:mime-version:content-type:from; b=DteOkJHv2zwqKsN4BxtyxKFUNplBgulZ6p4vno0brL3sTJE2icoxNQJ66I67HCtCpnQsOnw1be4rbzIPAC8DO7pSWwSfR84eyViTOpfYL6XvRZt8qDAXtvkjO4Mj6blo3yNf/ywMS9pYYr47g6eKyTkdohm55Fb0rd7lxFA+X40= Date: Fri, 14 Jul 2006 22:31:41 +0100 (BST) X-X-Sender: simlo@localhost.localdomain To: Jean-Marc Valin cc: Lee Revell , linux-kernel@vger.kernel.org, Ingo Molnar Subject: Re: Where is RLIMIT_RT_CPU? In-Reply-To: <1152869952.6374.8.camel@idefix.homelinux.org> Message-ID: References: <1152663825.27958.5.camel@localhost> <1152809039.8237.48.camel@mindpipe> <1152869952.6374.8.camel@idefix.homelinux.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed From: Esben Nielsen Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 14 Jul 2006, Jean-Marc Valin wrote: >> It was not merged. >> >> This problem should be addressed by a userspace RT watchdog. Ubuntu >> should not have shipped their system with unlimited non-root realtime >> enabled and no watchdog. > > Does such a daemon currently exist? Even then, is there any way to > police all unprivileged RT apps without introducing an O(N) operation > running continuously at max rt priority? Sort of defeats the purpose of > having an O(1) scheduler, no? I assume the RT check can be some in O(1) > time in the kernel, right? > Can't you just make a prio 1 task which signals a prio 99 once say every second. If the priority 99 task doesn't get the signal after say 2 seconds, it will look for a rt task running wild. At worst it will have to do an O(n) algorith when things have gone wrong, not when everything is working. Esben > About Ubuntu, I agree it wasn't a smart thing to do (I'm not an Ubuntu > devel, so I don't know what the reason was), but it would be nice if > this could be fixed without having to entirely remove the unprivileged > real-time feature. In the end, I'm not sure what the best solution is > (just an RT audio developer). > > Jean-Marc > - > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ >