[RFC][PATCH 2/2] sched: Enable interrupts in idle_balance()

[Steven Rostedt]

Now that the idle_balance is called from the post_schedule of the
idle task sched class, it is safe to enable interrupts. This allows
for better interaction of tasks waking up and other interrupts that
are triggered while the idle balance is in process.

Preemption is still disabled, but perhaps that can change as well.
That may need some more investigation.

Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>

Index: linux-trace.git/kernel/sched/fair.c
===================================================================
--- linux-trace.git.orig/kernel/sched/fair.c
+++ linux-trace.git/kernel/sched/fair.c
@@ -5231,9 +5231,10 @@ void idle_balance(int this_cpu, struct r
 	update_rq_runnable_avg(this_rq, 1);
 
 	/*
-	 * Drop the rq->lock, but keep IRQ/preempt disabled.
+	 * Drop the rq->lock, but keep preempt disabled.
 	 */
-	raw_spin_unlock(&this_rq->lock);
+	preempt_disable();
+	raw_spin_unlock_irq(&this_rq->lock);
 
 	update_blocked_averages(this_cpu);
 	rcu_read_lock();
@@ -5260,7 +5261,8 @@ void idle_balance(int this_cpu, struct r
 	}
 	rcu_read_unlock();
 
-	raw_spin_lock(&this_rq->lock);
+	raw_spin_lock_irq(&this_rq->lock);
+	preempt_enable();
 
 	if (pulled_task || time_after(jiffies, this_rq->next_balance)) {
 		/*

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