Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261550AbVAGUtA (ORCPT ); Fri, 7 Jan 2005 15:49:00 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261597AbVAGUtA (ORCPT ); Fri, 7 Jan 2005 15:49:00 -0500 Received: from waste.org ([216.27.176.166]:62676 "EHLO waste.org") by vger.kernel.org with ESMTP id S261550AbVAGUrI (ORCPT ); Fri, 7 Jan 2005 15:47:08 -0500 Date: Fri, 7 Jan 2005 12:46:50 -0800 From: Matt Mackall To: "Jack O'Quin" Cc: Alan Cox , Andreas Steinmetz , Lee Revell , Chris Wright , Linux Kernel Mailing List , Andrew Morton , Ingo Molnar , LAD mailing list Subject: Re: [PATCH] [request for inclusion] Realtime LSM Message-ID: <20050107204650.GY2940@waste.org> References: <20050103140359.GA19976@infradead.org> <1104862614.8255.1.camel@krustophenia.net> <20050104182010.GA15254@infradead.org> <1104865034.8346.4.camel@krustophenia.net> <41DB4476.8080400@domdv.de> <1104898693.24187.162.camel@localhost.localdomain> <20050107011820.GC2995@waste.org> <87brc17pj6.fsf@sulphur.joq.us> <20050107200245.GW2940@waste.org> <87mzvl56j5.fsf@sulphur.joq.us> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87mzvl56j5.fsf@sulphur.joq.us> User-Agent: Mutt/1.3.28i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1301 Lines: 32 On Fri, Jan 07, 2005 at 02:27:26PM -0600, Jack O'Quin wrote: > Matt Mackall writes: > > > On Thu, Jan 06, 2005 at 11:54:05PM -0600, Jack O'Quin wrote: > >> Note that sched_setschedule() provides no way to handle the mlock() > >> requirement, which cannot be done from another process. > > > > I'm pretty sure that part can be done by a privileged server handing > > out mlocked shared memory segments. > > If you're "pretty sure", please explain how locking a shared memory > segment prevents the code and stack of the client's realtime thread > from page faulting. You just map your RT-dependent routine (PIC, of course) into the segment and move your stack pointer into a second segment. I didn't say it was easy, but it's all just bits. There's also the rlimit issue. Or, going the other way, the client app can pass map handles to the server to bless. Some juggling might be involved but it's obviously doable. As has been pointed out, an rlimit solution exists now as well. -- Mathematics is the supreme nostalgia of our time. - 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/