static void rcu_idle_enter_common(struct rcu_dynticks *rdtp, long long oldval)
{
	trace_rcu_dyntick("Start", oldval, 0);
	if (!is_idle_task(current)) {
		struct task_struct *idle = idle_task(smp_processor_id());

		trace_rcu_dyntick("Error on entry: not idle task", oldval, 0);
		ftrace_dump(DUMP_ALL);
		WARN_ONCE(1, "Current pid: %d comm: %s / Idle pid: %d comm: %s",
			  current->pid, current->comm,
			  idle->pid, idle->comm); 
	}
	rcu_prepare_for_idle(smp_processor_id());
	
	smp_mb__before_atomic_inc();  
	atomic_inc(&rdtp->dynticks);
	smp_mb__after_atomic_inc();  
	WARN_ON_ONCE(atomic_read(&rdtp->dynticks) & 0x1);

	rcu_lockdep_assert(!lock_is_held(&rcu_lock_map),
			   "Illegal idle entry in RCU read-side critical section.");
	rcu_lockdep_assert(!lock_is_held(&rcu_bh_lock_map),
			   "Illegal idle entry in RCU-bh read-side critical section.");
	rcu_lockdep_assert(!lock_is_held(&rcu_sched_lock_map),
			   "Illegal idle entry in RCU-sched read-side critical section.");
}

/*
 * Wait for a grace period to elapse.  But it is illegal to invoke
 * synchronize_sched() from within an RCU read-side critical section.
 * Therefore, any legal call to synchronize_sched() is a quiescent
 * state, and so on a UP system, synchronize_sched() need do nothing.
 * Ditto for synchronize_rcu_bh().  (But Lai Jiangshan points out the
 * benefits of doing might_sleep() to reduce latency.)
 *
 * Cool, huh?  (Due to Josh Triplett.)
 *
 * But we want to make this a static inline later.  The cond_resched()
 * currently makes this problematic.
 */
void synchronize_sched(void)
{
	rcu_lockdep_assert(!lock_is_held(&rcu_bh_lock_map) &&
			   !lock_is_held(&rcu_lock_map) &&
			   !lock_is_held(&rcu_sched_lock_map),
			   "Illegal synchronize_sched() in RCU read-side critical section");
	cond_resched();
}