Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261505AbVA1IIW (ORCPT ); Fri, 28 Jan 2005 03:08:22 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261510AbVA1IIW (ORCPT ); Fri, 28 Jan 2005 03:08:22 -0500 Received: from mx2.elte.hu ([157.181.151.9]:65182 "EHLO mx2.elte.hu") by vger.kernel.org with ESMTP id S261505AbVA1IIU (ORCPT ); Fri, 28 Jan 2005 03:08:20 -0500 Date: Fri, 28 Jan 2005 09:08:02 +0100 From: Ingo Molnar To: Nick Piggin Cc: "Jack O'Quin" , Paul Davis , Con Kolivas , linux , rlrevell@joe-job.com, CK Kernel , utz , Andrew Morton , alexn@dsv.su.se, Rui Nuno Capela , Chris Wright , Arjan van de Ven Subject: Re: [patch, 2.6.11-rc2] sched: RLIMIT_RT_CPU_RATIO feature Message-ID: <20050128080802.GA2860@elte.hu> References: <87wtu6fho8.fsf@sulphur.joq.us> <20050122165458.GA14426@elte.hu> <87hdl940ph.fsf@sulphur.joq.us> <20050124085902.GA8059@elte.hu> <20050124125814.GA31471@elte.hu> <20050125135613.GA18650@elte.hu> <87sm4opxto.fsf@sulphur.joq.us> <20050126070404.GA27280@elte.hu> <87fz0neshg.fsf@sulphur.joq.us> <1106782165.5158.15.camel@npiggin-nld.site> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1106782165.5158.15.camel@npiggin-nld.site> User-Agent: Mutt/1.4.1i X-ELTE-SpamVersion: MailScanner 4.31.6-itk1 (ELTE 1.2) SpamAssassin 2.63 ClamAV 0.73 X-ELTE-VirusStatus: clean X-ELTE-SpamCheck: no X-ELTE-SpamCheck-Details: score=-4.9, required 5.9, autolearn=not spam, BAYES_00 -4.90 X-ELTE-SpamLevel: X-ELTE-SpamScore: -4 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1042 Lines: 23 * Nick Piggin wrote: > And finally, with rlimit support, is there any reason why lockup > detection and correction can't go into userspace? Even RT throttling > could probably be done in a userspace daemon. that is correct. Jackd already has a watchdog thread, against lockups. i'm wondering, couldnt Jackd solve this whole issue completely in user-space, via a simple setuid-root wrapper app that does nothing else but validates whether the user is in the 'jackd' group and then keeps a pipe open to to the real jackd process which it forks off, deprivileges and exec()s? Then unprivileged jackd could request RT-priority changes via that pipe in a straightforward way. Jack normally gets installed as root/admin anyway, so it's not like this couldnt be done. Ingo - 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/