From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755077Ab3IIPau (ORCPT ); Mon, 9 Sep 2013 11:30:50 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:31424 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754117Ab3IIP0p (ORCPT ); Mon, 9 Sep 2013 11:26:45 -0400 X-Authority-Analysis: v=2.0 cv=ddwCLAre c=1 sm=0 a=Sro2XwOs0tJUSHxCKfOySw==:17 a=Drc5e87SC40A:10 a=Ciwy3NGCPMMA:10 a=bhxVZlKqwjsA:10 a=5SG0PmZfjMsA:10 a=bbbx4UPp9XUA:10 a=meVymXHHAAAA:8 a=KGjhK52YXX0A:10 a=xPLaIx7fqxsA:10 a=pGLkceISAAAA:8 a=VwQbUJbxAAAA:8 a=9HL7raVLAAAA:8 a=Yj-eAbKCAAAA:8 a=_UZCbbHauV_kxHeOyvkA:9 a=ucBF-G1wxy4A:10 a=MSl-tDqOz04A:10 a=Zh68SRI7RUMA:10 a=jeBq3FmKZ4MA:10 a=Sro2XwOs0tJUSHxCKfOySw==:117 X-Cloudmark-Score: 0 X-Authenticated-User: X-Originating-IP: 67.255.60.225 Message-Id: <20130909143534.655639785@goodmis.org> User-Agent: quilt/0.60-1 Date: Mon, 09 Sep 2013 10:35:20 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org, linux-rt-users Cc: Thomas Gleixner , Carsten Emde , Sebastian Andrzej Siewior , John Kacur , , Ivo Sieben Subject: [PATCH RT 03/16] genirq: Set irq thread to RT priority on creation References: <20130909143517.641735717@goodmis.org> Content-Disposition: inline; filename=0003-genirq-Set-irq-thread-to-RT-priority-on-creation.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Ivo Sieben When a threaded irq handler is installed the irq thread is initially created on normal scheduling priority. Only after the irq thread is woken up it sets its priority to RT_FIFO MAX_USER_RT_PRIO/2 itself. This means that interrupts that occur directly after the irq handler is installed will be handled on a normal scheduling priority instead of the realtime priority that one would expect. Fix this by setting the RT priority on creation of the irq_thread. Cc: stable-rt@vger.kernel.org Signed-off-by: Ivo Sieben Cc: Sebastian Andrzej Siewior Cc: Steven Rostedt Link: http://lkml.kernel.org/r/1370254322-17240-1-git-send-email-meltedpianoman@gmail.com Signed-off-by: Thomas Gleixner Signed-off-by: Sebastian Andrzej Siewior --- kernel/irq/manage.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index d750268..9d702cf 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -780,9 +780,6 @@ static irqreturn_t irq_thread_fn(struct irq_desc *desc, */ static int irq_thread(void *data) { - static const struct sched_param param = { - .sched_priority = MAX_USER_RT_PRIO/2, - }; struct irqaction *action = data; struct irq_desc *desc = irq_to_desc(action->irq); irqreturn_t (*handler_fn)(struct irq_desc *desc, @@ -795,7 +792,6 @@ static int irq_thread(void *data) else handler_fn = irq_thread_fn; - sched_setscheduler(current, SCHED_FIFO, ¶m); current->irqaction = action; while (!irq_wait_for_interrupt(action)) { @@ -932,11 +928,17 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new) */ if (new->thread_fn && !nested) { struct task_struct *t; + static const struct sched_param param = { + .sched_priority = MAX_USER_RT_PRIO/2, + }; t = kthread_create(irq_thread, new, "irq/%d-%s", irq, new->name); if (IS_ERR(t)) return PTR_ERR(t); + + sched_setscheduler(t, SCHED_FIFO, ¶m); + /* * We keep the reference to the task struct even if * the thread dies to avoid that the interrupt code -- 1.7.10.4