Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262111AbVANVDY (ORCPT ); Fri, 14 Jan 2005 16:03:24 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262058AbVANUxt (ORCPT ); Fri, 14 Jan 2005 15:53:49 -0500 Received: from viper.oldcity.dca.net ([216.158.38.4]:8870 "HELO viper.oldcity.dca.net") by vger.kernel.org with SMTP id S262134AbVANUwq (ORCPT ); Fri, 14 Jan 2005 15:52:46 -0500 Subject: Re: [PATCH] [request for inclusion] Realtime LSM From: Lee Revell To: "Jack O'Quin" Cc: Matt Mackall , Ingo Molnar , Chris Wright , Paul Davis , Christoph Hellwig , Con Kolivas , Andrew Morton , arjanv@redhat.com, alan@lxorguk.ukuu.org.uk, linux-kernel@vger.kernel.org In-Reply-To: <87is61b0l4.fsf@sulphur.joq.us> References: <20050110212019.GG2995@waste.org> <200501111305.j0BD58U2000483@localhost.localdomain> <20050111191701.GT2940@waste.org> <20050111125008.K10567@build.pdx.osdl.net> <20050111205809.GB21308@elte.hu> <20050111131400.L10567@build.pdx.osdl.net> <20050111212719.GA23477@elte.hu> <87fz15j325.fsf@sulphur.joq.us> <20050113063446.GV2940@waste.org> <87is61b0l4.fsf@sulphur.joq.us> Content-Type: text/plain Date: Fri, 14 Jan 2005 15:52:44 -0500 Message-Id: <1105735965.7258.24.camel@krustophenia.net> Mime-Version: 1.0 X-Mailer: Evolution 2.0.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1420 Lines: 30 On Thu, 2005-01-13 at 13:17 -0600, Jack O'Quin wrote: > But there may be other, better solutions to the deadlock problem. > Several years ago, Roger Larsson wrote a completely user-space > realtime monitor program that works perfectly well for revoking > realtime privileges when it detects CPU starvation. I still use it > occasionally to help debug problems if the built-in JACK watchdog > timer doesn't catch them. Jack, Do you have a link to Roger Larsson's RT watchdog? Since we seem to have a consensus that the rlimit approach is the way to go, I think it will be important to have a generic watchdog thread running as root at a higher RT prio than the RT group. JACK solves the problem with its own watchdog thread but as more and more apps migrate to (in our opinion) the "correct" RT programming model, where you have multithreaded apps with normal prio disk and GUI threads feeding an RT rendering thread, a system wide watchdog daemon becomes more attractive. Keep in mind there are many other applications than audio, for example CD burning has an obvious RT constraint and cdrecord will take advantage of SCHED_FIFO and mlockall() if it can get them. Lee - 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/