Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759051AbXJOOgj (ORCPT ); Mon, 15 Oct 2007 10:36:39 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755105AbXJOOgb (ORCPT ); Mon, 15 Oct 2007 10:36:31 -0400 Received: from tango.0pointer.de ([85.214.72.216]:35210 "EHLO tango.0pointer.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755299AbXJOOga (ORCPT ); Mon, 15 Oct 2007 10:36:30 -0400 X-Greylist: delayed 642 seconds by postgrey-1.27 at vger.kernel.org; Mon, 15 Oct 2007 10:36:30 EDT Date: Mon, 15 Oct 2007 16:25:46 +0200 From: Lennart Poettering To: Peter Zijlstra Cc: linux-kernel , Ingo Molnar , Thomas Gleixner , Mike Galbraith Subject: Re: [RFC][PATCH] sched: SCHED_FIFO watchdog timer Message-ID: <20071015142546.GA7851@tango.0pointer.de> References: <1192222309.5897.3.camel@lappy> <1192315867.5625.6.camel@lappy> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1192315867.5625.6.camel@lappy> Organization: Red Hat, Inc. X-Campaign-1: () ASCII Ribbon Campaign X-Campaign-2: / Against HTML Email & vCards - Against Microsoft Attachments User-Agent: Leviathan/19.8.0 [zh] (Cray 3; I; Solaris 4.711; Console) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1596 Lines: 35 On Sun, 14.10.07 00:51, Peter Zijlstra (a.p.zijlstra@chello.nl) wrote: > The below patch is an idea proposed by tglx and depends on sched-devel + > the hrtick patch previously posted. > > The current watchdog action is to demote the task to SCHED_NORMAL, > however it might be wanted to deliver a signal instead (or have more per > task configuration state). Which is why I added Lennart to the CC list > as I gathered he would like something like this for PulseAudio. Indeed! Having this in the kernel would allow us to enable RT scheduling for PulseAudio by default without bad effects. I was thinking about adding some kind of babysitting process to userspace -- but doing this as an RLIMIT in the kernel strikes me a much better idea! I think it would make a lot of sense to make the API very similar to RLIMIT_CPU, i.e. also send out SIGXCPU and SIGKILL, with the single difference that RLIMIT_CPU sends out a signal depending on the total CPU time used for the process and the new RLIMIT based on the time the process spent without sleeping. That would be a very reasonable extension to the current RLIMIT_CPU model. Thank you very much for doing this patch! Lennart -- Lennart Poettering Red Hat, Inc. lennart [at] poettering [dot] net ICQ# 11060553 http://0pointer.net/lennart/ GnuPG 0x1A015CC4 - 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/