#ifdef CONFIG_SCHED_AUTOGROUP

  #include <linux/kref.h>
  #include <linux/rwsem.h>

  struct autogroup {

  	/*
  	 * reference doesn't mean how many thread attach to this
  	 * autogroup now. It just stands for the number of task
  	 * could use this autogroup.
  	 */

  	struct kref		kref;
  	struct task_group	*tg;
  	struct rw_semaphore	lock;
  	unsigned long		id;
  	int			nice;
  };

  extern void autogroup_init(struct task_struct *init_task);
  extern void autogroup_free(struct task_group *tg);
  
  static inline bool task_group_is_autogroup(struct task_group *tg)
  {
  	return !!tg->autogroup;
  }
  
  extern bool task_wants_autogroup(struct task_struct *p, struct task_group *tg);

  static inline struct task_group *

  autogroup_task_group(struct task_struct *p, struct task_group *tg)
  {

  	int enabled = READ_ONCE(sysctl_sched_autogroup_enabled);

  
  	if (enabled && task_wants_autogroup(p, tg))

  		return p->signal->autogroup->tg;
  
  	return tg;
  }
  
  extern int autogroup_path(struct task_group *tg, char *buf, int buflen);

  
  #else /* !CONFIG_SCHED_AUTOGROUP */
  
  static inline void autogroup_init(struct task_struct *init_task) {  }
  static inline void autogroup_free(struct task_group *tg) { }

  static inline bool task_group_is_autogroup(struct task_group *tg)
  {
  	return 0;
  }

  
  static inline struct task_group *
  autogroup_task_group(struct task_struct *p, struct task_group *tg)
  {
  	return tg;
  }
  
  #ifdef CONFIG_SCHED_DEBUG
  static inline int autogroup_path(struct task_group *tg, char *buf, int buflen)
  {
  	return 0;
  }
  #endif
  
  #endif /* CONFIG_SCHED_AUTOGROUP */