diff options
authorIvo Sieben <meltedpianoman@gmail.com>2013-06-03 12:12:02 +0200
committerThomas Gleixner <tglx@linutronix.de>2013-06-11 16:18:50 +0200
commitee23871389d51e07380d23887333622fbe7d3dd9 (patch)
parent9dbd90f17e4f380593ec5194c2a4d5e52c5f72d1 (diff)
genirq: Set irq thread to RT priority on creation
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. Signed-off-by: Ivo Sieben <meltedpianoman@gmail.com> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/1370254322-17240-1-git-send-email-meltedpianoman@gmail.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
1 files changed, 6 insertions, 5 deletions
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index fa17855ca65a..e16caa81f887 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -840,9 +840,6 @@ static void irq_thread_dtor(struct callback_head *unused)
static int irq_thread(void *data)
struct callback_head on_exit_work;
- 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,
@@ -854,8 +851,6 @@ static int irq_thread(void *data)
handler_fn = irq_thread_fn;
- sched_setscheduler(current, SCHED_FIFO, &param);
init_task_work(&on_exit_work, irq_thread_dtor);
task_work_add(current, &on_exit_work, false);
@@ -950,6 +945,9 @@ __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,
@@ -957,6 +955,9 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
ret = PTR_ERR(t);
goto out_mput;
+ sched_setscheduler(t, SCHED_FIFO, &param);
* We keep the reference to the task struct even if
* the thread dies to avoid that the interrupt code