Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932726AbWEXPwk (ORCPT ); Wed, 24 May 2006 11:52:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932723AbWEXPwk (ORCPT ); Wed, 24 May 2006 11:52:40 -0400 Received: from ms-smtp-03.nyroc.rr.com ([24.24.2.57]:16601 "EHLO ms-smtp-03.nyroc.rr.com") by vger.kernel.org with ESMTP id S932726AbWEXPwj (ORCPT ); Wed, 24 May 2006 11:52:39 -0400 Subject: Re: Ingo's realtime_preempt patch causes kernel oops From: Steven Rostedt To: Sven-Thorsten Dietrich Cc: tglx@linutronix.de, Yann.LEPROVOST@wavecom.fr, Daniel Walker , linux-kernel@vger.kernel.org, linux-kernel-owner@vger.kernel.org, Ingo Molnar In-Reply-To: <1148484729.14683.5.camel@localhost.localdomain> References: <1148475334.24623.45.camel@localhost.localdomain> <1148476383.5239.54.camel@localhost.localdomain> <1148484729.14683.5.camel@localhost.localdomain> Content-Type: text/plain Date: Wed, 24 May 2006 11:52:23 -0400 Message-Id: <1148485943.24623.54.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.4.2.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1367 Lines: 32 On Wed, 2006-05-24 at 08:32 -0700, Sven-Thorsten Dietrich wrote: > On Wed, 2006-05-24 at 15:13 +0200, Thomas Gleixner wrote: > > On Wed, 2006-05-24 at 08:55 -0400, Steven Rostedt wrote: > > > Thomas or Ingo, > > > > > > Maybe the handling of IRQs needs to handle the case that shared irq can > > > have both a NODELAY and a thread. The irq descriptor could have a > > > NODELAY set if any of the actions are NODELAY, but before calling the > > > interrupt handler (in interrupt context), check if the action is NODELAY > > > or not, and if not, wake up the thread if not done so already. > > > > As I said yesterday. You need a demultiplexer for such cases. > > > > Would IRQs stay masked until the thread has finished running? I would say yes. But the system is basically broken if you have the same interrupt line that needs both to be threaded and NODELAY. Basically, the best I can think to have for such a case, is all interrupt threads that have a shared NODELAY run at MAX_PRIO (99). So that they act like a NODELAY interrupt, in that they run over everything else, but they can still schedule. -- Steve - 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/