#ifdef CONFIG_SCHEDSTATS

  /*
   * Expects runqueue lock to be held for atomicity of update
   */
  static inline void
  rq_sched_info_arrive(struct rq *rq, unsigned long long delta)
  {
  	if (rq) {
  		rq->rq_sched_info.run_delay += delta;

  		rq->rq_sched_info.pcount++;

  	}
  }
  
  /*
   * Expects runqueue lock to be held for atomicity of update
   */
  static inline void
  rq_sched_info_depart(struct rq *rq, unsigned long long delta)
  {
  	if (rq)

  		rq->rq_cpu_time += delta;

  }

  
  static inline void
  rq_sched_info_dequeued(struct rq *rq, unsigned long long delta)
  {
  	if (rq)
  		rq->rq_sched_info.run_delay += delta;
  }

  #define schedstat_enabled()		static_branch_unlikely(&sched_schedstats)
  #define schedstat_inc(var)		do { if (schedstat_enabled()) { var++; } } while (0)
  #define schedstat_add(var, amt)		do { if (schedstat_enabled()) { var += (amt); } } while (0)
  #define schedstat_set(var, val)		do { if (schedstat_enabled()) { var = (val); } } while (0)

  #define schedstat_val(var)		(var)
  #define schedstat_val_or_zero(var)	((schedstat_enabled()) ? (var) : 0)

  #else /* !CONFIG_SCHEDSTATS */
  static inline void
  rq_sched_info_arrive(struct rq *rq, unsigned long long delta)
  {}
  static inline void

  rq_sched_info_dequeued(struct rq *rq, unsigned long long delta)
  {}
  static inline void

  rq_sched_info_depart(struct rq *rq, unsigned long long delta)
  {}

  #define schedstat_enabled()		0
  #define schedstat_inc(var)		do { } while (0)
  #define schedstat_add(var, amt)		do { } while (0)
  #define schedstat_set(var, val)		do { } while (0)
  #define schedstat_val(var)		0

  #define schedstat_val_or_zero(var)	0

  #endif /* CONFIG_SCHEDSTATS */

  #ifdef CONFIG_SCHED_INFO

  static inline void sched_info_reset_dequeued(struct task_struct *t)
  {
  	t->sched_info.last_queued = 0;
  }

  /*

   * We are interested in knowing how long it was from the *first* time a

   * task was queued to the time that it finally hit a cpu, we call this routine
   * from dequeue_task() to account for possible rq->clock skew across cpus. The
   * delta taken on each cpu would annul the skew.

   */

  static inline void sched_info_dequeued(struct rq *rq, struct task_struct *t)

  {

  	unsigned long long now = rq_clock(rq), delta = 0;

  
  	if (unlikely(sched_info_on()))
  		if (t->sched_info.last_queued)
  			delta = now - t->sched_info.last_queued;
  	sched_info_reset_dequeued(t);
  	t->sched_info.run_delay += delta;

  	rq_sched_info_dequeued(rq, delta);

  }
  
  /*
   * Called when a task finally hits the cpu.  We can now calculate how
   * long it was waiting to run.  We also note when it began so that we
   * can keep stats on how long its timeslice is.
   */

  static void sched_info_arrive(struct rq *rq, struct task_struct *t)

  {

  	unsigned long long now = rq_clock(rq), delta = 0;

  
  	if (t->sched_info.last_queued)
  		delta = now - t->sched_info.last_queued;

  	sched_info_reset_dequeued(t);

  	t->sched_info.run_delay += delta;
  	t->sched_info.last_arrival = now;

  	t->sched_info.pcount++;

  	rq_sched_info_arrive(rq, delta);

  }
  
  /*

   * This function is only called from enqueue_task(), but also only updates
   * the timestamp if it is already not set.  It's assumed that
   * sched_info_dequeued() will clear that stamp when appropriate.
   */

  static inline void sched_info_queued(struct rq *rq, struct task_struct *t)

  {
  	if (unlikely(sched_info_on()))
  		if (!t->sched_info.last_queued)

  			t->sched_info.last_queued = rq_clock(rq);

  }
  
  /*

   * Called when a process ceases being the active-running process involuntarily
   * due, typically, to expiring its time slice (this may also be called when
   * switching to the idle task).  Now we can calculate how long we ran.

   * Also, if the process is still in the TASK_RUNNING state, call
   * sched_info_queued() to mark that it has now again started waiting on
   * the runqueue.

   */

  static inline void sched_info_depart(struct rq *rq, struct task_struct *t)

  {

  	unsigned long long delta = rq_clock(rq) -

  					t->sched_info.last_arrival;

  	rq_sched_info_depart(rq, delta);

  
  	if (t->state == TASK_RUNNING)

  		sched_info_queued(rq, t);

  }
  
  /*
   * Called when tasks are switched involuntarily due, typically, to expiring
   * their time slice.  (This may also be called when switching to or from
   * the idle task.)  We are only called when prev != next.
   */
  static inline void

  __sched_info_switch(struct rq *rq,
  		    struct task_struct *prev, struct task_struct *next)

  {

  	/*
  	 * prev now departs the cpu.  It's not interesting to record
  	 * stats about how efficient we were at scheduling the idle
  	 * process, however.
  	 */
  	if (prev != rq->idle)

  		sched_info_depart(rq, prev);

  
  	if (next != rq->idle)

  		sched_info_arrive(rq, next);

  }
  static inline void

  sched_info_switch(struct rq *rq,
  		  struct task_struct *prev, struct task_struct *next)

  {
  	if (unlikely(sched_info_on()))

  		__sched_info_switch(rq, prev, next);

  }
  #else

  #define sched_info_queued(rq, t)		do { } while (0)

  #define sched_info_reset_dequeued(t)	do { } while (0)

  #define sched_info_dequeued(rq, t)		do { } while (0)
  #define sched_info_depart(rq, t)		do { } while (0)
  #define sched_info_arrive(rq, next)		do { } while (0)
  #define sched_info_switch(rq, t, next)		do { } while (0)

  #endif /* CONFIG_SCHED_INFO */

  /*
   * The following are functions that support scheduler-internal time accounting.
   * These functions are generally called at the timer tick.  None of this depends
   * on CONFIG_SCHEDSTATS.
   */

  /**

   * cputimer_running - return true if cputimer is running
   *
   * @tsk:	Pointer to target task.
   */
  static inline bool cputimer_running(struct task_struct *tsk)
  
  {
  	struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;

  	/* Check if cputimer isn't running. This is accessed without locking. */
  	if (!READ_ONCE(cputimer->running))

  		return false;
  
  	/*
  	 * After we flush the task's sum_exec_runtime to sig->sum_sched_runtime
  	 * in __exit_signal(), we won't account to the signal struct further
  	 * cputime consumed by that task, even though the task can still be
  	 * ticking after __exit_signal().
  	 *
  	 * In order to keep a consistent behaviour between thread group cputime
  	 * and thread group cputimer accounting, lets also ignore the cputime
  	 * elapsing after __exit_signal() in any thread group timer running.
  	 *
  	 * This makes sure that POSIX CPU clocks and timers are synchronized, so
  	 * that a POSIX CPU timer won't expire while the corresponding POSIX CPU
  	 * clock delta is behind the expiring timer value.
  	 */
  	if (unlikely(!tsk->sighand))
  		return false;
  
  	return true;
  }
  
  /**

   * account_group_user_time - Maintain utime for a thread group.

   *

   * @tsk:	Pointer to task structure.
   * @cputime:	Time value by which to increment the utime field of the
   *		thread_group_cputime structure.

   *
   * If thread group time is being maintained, get the structure for the
   * running CPU and update the utime field there.
   */

  static inline void account_group_user_time(struct task_struct *tsk,
  					   cputime_t cputime)

  {

  	struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;

  	if (!cputimer_running(tsk))

  		return;

  	atomic64_add(cputime, &cputimer->cputime_atomic.utime);

  }
  
  /**

   * account_group_system_time - Maintain stime for a thread group.

   *

   * @tsk:	Pointer to task structure.
   * @cputime:	Time value by which to increment the stime field of the
   *		thread_group_cputime structure.

   *
   * If thread group time is being maintained, get the structure for the
   * running CPU and update the stime field there.
   */

  static inline void account_group_system_time(struct task_struct *tsk,
  					     cputime_t cputime)

  {

  	struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;

  	if (!cputimer_running(tsk))

  		return;

  	atomic64_add(cputime, &cputimer->cputime_atomic.stime);

  }
  
  /**

   * account_group_exec_runtime - Maintain exec runtime for a thread group.

   *

   * @tsk:	Pointer to task structure.

   * @ns:		Time value by which to increment the sum_exec_runtime field

   *		of the thread_group_cputime structure.

   *
   * If thread group time is being maintained, get the structure for the
   * running CPU and update the sum_exec_runtime field there.
   */

  static inline void account_group_exec_runtime(struct task_struct *tsk,
  					      unsigned long long ns)

  {

  	struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;

  	if (!cputimer_running(tsk))

  		return;

  	atomic64_add(ns, &cputimer->cputime_atomic.sum_exec_runtime);

  }