asmlinkage void __sched schedule(void)
{
	struct task_struct *prev, *next;
	unsigned long *switch_count;
	struct rq *rq;
	int cpu;

need_resched:
	preempt_disable();
	cpu = smp_processor_id();
	rq = cpu_rq(cpu);
	rcu_note_context_switch(cpu);
	prev = rq->curr;

	release_kernel_lock(prev);
need_resched_nonpreemptible:

	schedule_debug(prev);

	if (sched_feat(HRTICK))
		hrtick_clear(rq);

	raw_spin_lock_irq(&rq->lock);

	switch_count = &prev->nivcsw;
	if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) {
		if (unlikely(signal_pending_state(prev->state, prev))) {
			prev->state = TASK_RUNNING;
		} else {
			/*
			 * If a worker is going to sleep, notify and
			 * ask workqueue whether it wants to wake up a
			 * task to maintain concurrency.  If so, wake
			 * up the task.
			 */
			if (prev->flags & PF_WQ_WORKER) {
				struct task_struct *to_wakeup;

				to_wakeup = wq_worker_sleeping(prev, cpu);
				if (to_wakeup)
					try_to_wake_up_local(to_wakeup);
			}
			deactivate_task(rq, prev, DEQUEUE_SLEEP);
		}
		switch_count = &prev->nvcsw;
	}

	pre_schedule(rq, prev);

	if (unlikely(!rq->nr_running))
		idle_balance(cpu, rq);

	put_prev_task(rq, prev);
	next = pick_next_task(rq);
	clear_tsk_need_resched(prev);
	rq->skip_clock_update = 0;

	if (likely(prev != next)) {
		sched_info_switch(prev, next);
		perf_event_task_sched_out(prev, next);

		rq->nr_switches++;
		rq->curr = next;
		++*switch_count;
		WARN_ON_ONCE(test_tsk_need_resched(next));

		context_switch(rq, prev, next); /* unlocks the rq */
		/*
		 * The context switch have flipped the stack from under us
		 * and restored the local variables which were saved when
		 * this task called schedule() in the past. prev == current
		 * is still correct, but it can be moved to another cpu/rq.
		 */
		cpu = smp_processor_id();
		rq = cpu_rq(cpu);
	} else
		raw_spin_unlock_irq(&rq->lock);

	post_schedule(rq);

	if (unlikely(reacquire_kernel_lock(prev)))
		goto need_resched_nonpreemptible;

	preempt_enable_no_resched();
	if (need_resched())
		goto need_resched;
}
asmlinkage void __sched schedule(void)
{
	struct task_struct *prev, *next;
	unsigned long *switch_count;
	struct rq *rq;
	int cpu;

need_resched:
	preempt_disable();
	cpu = smp_processor_id();
	rq = cpu_rq(cpu);
	rcu_note_context_switch(cpu);
	prev = rq->curr;

	release_kernel_lock(prev);
need_resched_nonpreemptible:

	schedule_debug(prev);

	if (sched_feat(HRTICK))
		hrtick_clear(rq);

	raw_spin_lock_irq(&rq->lock);

	switch_count = &prev->nivcsw;
	if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) {
		if (unlikely(signal_pending_state(prev->state, prev))) {
			prev->state = TASK_RUNNING;
		} else {
			 
			if (prev->flags & PF_WQ_WORKER) {
				struct task_struct *to_wakeup;

				to_wakeup = wq_worker_sleeping(prev, cpu);
				if (to_wakeup)
					try_to_wake_up_local(to_wakeup);
			}
			deactivate_task(rq, prev, DEQUEUE_SLEEP);
		}
		switch_count = &prev->nvcsw;
	}

	pre_schedule(rq, prev);

	if (unlikely(!rq->nr_running))
		idle_balance(cpu, rq);

	put_prev_task(rq, prev);
	next = pick_next_task(rq);
	clear_tsk_need_resched(prev);
	rq->skip_clock_update = 0;

	if (likely(prev != next)) {
		sched_info_switch(prev, next);
		perf_event_task_sched_out(prev, next);

		rq->nr_switches++;
		rq->curr = next;
		++*switch_count;
		WARN_ON_ONCE(test_tsk_need_resched(next));

		context_switch(rq, prev, next);  
		 
		cpu = smp_processor_id();
		rq = cpu_rq(cpu);
	} else
		raw_spin_unlock_irq(&rq->lock);

	post_schedule(rq);

	if (unlikely(reacquire_kernel_lock(prev)))
		goto need_resched_nonpreemptible;

	preempt_enable_no_resched();
	if (need_resched())
		goto need_resched;
}