Exemple #1
0
/*
 * The idle thread. There's no useful work to be
 * done, so just try to conserve power and have a
 * low exit latency (ie sit in a loop waiting for
 * somebody to say that they'd like to reschedule)
 */
void cpu_idle(void)
{
	int cpu = smp_processor_id();


	current_thread_info()->status |= TS_POLLING;

	if (no_idle_nap) {
		while (1) {
			while (!need_resched())
				cpu_relax();
			schedule();
		}
	}

	/* endless idle loop with no priority at all */
	while (1) {
		tick_nohz_stop_sched_tick(1);
		while (!need_resched()) {
			if (cpu_is_offline(cpu))
				BUG();  /* no HOTPLUG_CPU */

			local_irq_disable();
			__get_cpu_var(irq_stat).idle_timestamp = jiffies;
			current_thread_info()->status &= ~TS_POLLING;
			/*
			 * TS_POLLING-cleared state must be visible before we
			 * test NEED_RESCHED:
			 */
			smp_mb();

			if (!need_resched())
				_cpu_idle();
			else
				local_irq_enable();
			current_thread_info()->status |= TS_POLLING;
		}
		tick_nohz_restart_sched_tick();
		preempt_enable_no_resched();
		schedule();
		preempt_disable();
	}
}
Exemple #2
0
static void _idletask(void)
{
	for (;;){
		_cpu_idle();
	}
}