Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759954Ab3E3Tux (ORCPT ); Thu, 30 May 2013 15:50:53 -0400 Received: from www.linutronix.de ([62.245.132.108]:35043 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753849Ab3E3Tuo (ORCPT ); Thu, 30 May 2013 15:50:44 -0400 Date: Thu, 30 May 2013 21:50:41 +0200 (CEST) From: Thomas Gleixner To: Steven Rostedt cc: Ivo Sieben , RT , Sebastian Andrzej Siewior , LKML Subject: Re: [PATCH] RFC: Set irq thread to RT priority on creation In-Reply-To: <1369925681.26799.6.camel@gandalf.local.home> Message-ID: References: <1369915975-28797-1-git-send-email-meltedpianoman@gmail.com> <1369925681.26799.6.camel@gandalf.local.home> User-Agent: Alpine 2.02 (LFD 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1120 Lines: 32 On Thu, 30 May 2013, Steven Rostedt wrote: > On Thu, 2013-05-30 at 16:07 +0200, Thomas Gleixner wrote: > > > > This patch solves an issue for me where a device driver is expected to handle an > > > interrupt immediatly after irq handlers are installed and interrupts enabled. > > > > You miss to explain what kind of issue that is. > > I could envision the case where the interrupt is initialized but doesn't > go off until much later. If it never ran, then it would still be in > SCHED_OTHER(), and that first interrupt could have a large delay. Nope. As Ivo explained it's about an interrupt coming in right away, i.e. before __setup_irq() reaches: if (new->thread) wake_up_process(new->thread); The ones which come much later do not have that issue as the thread code already sits in the waiting loop and already adjusted the priority. Thanks, tglx -- 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/