Linux Kernel调度管理之sched_class

本文主要是介绍Linux Kernel调度管理之sched_class，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

sched_class是Linux内核为不同调度策略定义的调度类：

struct sched_class {
	const struct sched_class *next;
	void (*enqueue_task) (struct rq *rq, struct task_struct *p, int flags);
	void (*dequeue_task) (struct rq *rq, struct task_struct *p, int flags);
	void (*yield_task) (struct rq *rq);
	bool (*yield_to_task) (struct rq *rq, struct task_struct *p, bool preempt);
	void (*check_preempt_curr) (struct rq *rq, struct task_struct *p, int flags);
	/*
	 * It is the responsibility of the pick_next_task() method that will
	 * return the next task to call put_prev_task() on the @prev task or
	 * something equivalent.
	 *
	 * May return RETRY_TASK when it finds a higher prio class has runnable
	 * tasks.
	 */
	struct task_struct * (*pick_next_task) (struct rq *rq,
						struct task_struct *prev,
						struct pin_cookie cookie);
	void (*put_prev_task) (struct rq *rq, struct task_struct *p);
#ifdef CONFIG_SMP
	int  (*select_task_rq)(struct task_struct *p, int task_cpu, int sd_flag, int flags);
	void (*migrate_task_rq)(struct task_struct *p);
	void (*task_woken) (struct rq *this_rq, struct task_struct *task);
	void (*set_cpus_allowed)(struct task_struct *p,
				 const struct cpumask *newmask);
	void (*rq_online)(struct rq *rq);
	void (*rq_offline)(struct rq *rq);
#endif
	void (*set_curr_task) (struct rq *rq);
	void (*task_tick) (struct rq *rq, struct task_struct *p, int queued);
	void (*task_fork) (struct task_struct *p);
	void (*task_dead) (struct task_struct *p);
	/*
	 * The switched_from() call is allowed to drop rq->lock, therefore we
	 * cannot assume the switched_from/switched_to pair is serliazed by
	 * rq->lock. They are however serialized by p->pi_lock.
	 */
	void (*switched_from) (struct rq *this_rq, struct task_struct *task);
	void (*switched_to) (struct rq *this_rq, struct task_struct *task);
	void (*prio_changed) (struct rq *this_rq, struct task_struct *task,
			     int oldprio);
	unsigned int (*get_rr_interval) (struct rq *rq,
					 struct task_struct *task);
	void (*update_curr) (struct rq *rq);
#define TASK_SET_GROUP  0
#define TASK_MOVE_GROUP	1
#ifdef CONFIG_FAIR_GROUP_SCHED
	void (*task_change_group) (struct task_struct *p, int type);
#endif
};

内核中的调度类都是静态定义的，调度类不能动态的注册。

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