/* delayacct.h - per-task delay accounting
   *
   * Copyright (C) Shailabh Nagar, IBM Corp. 2006
   *
   * This program is free software;  you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; either version 2 of the License, or
   * (at your option) any later version.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY;  without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
   * the GNU General Public License for more details.
   *
   */
  
  #ifndef _LINUX_DELAYACCT_H
  #define _LINUX_DELAYACCT_H
  
  #include <linux/sched.h>

  #include <linux/slab.h>

  /*
   * Per-task flags relevant to delay accounting
   * maintained privately to avoid exhausting similar flags in sched.h:PF_*
   * Used to set current->delays->flags
   */
  #define DELAYACCT_PF_SWAPIN	0x00000001	/* I am doing a swapin */

  #define DELAYACCT_PF_BLKIO	0x00000002	/* I am waiting on IO */

  #ifdef CONFIG_TASK_DELAY_ACCT
  
  extern int delayacct_on;	/* Delay accounting turned on/off */

  extern struct kmem_cache *delayacct_cache;

  extern void delayacct_init(void);
  extern void __delayacct_tsk_init(struct task_struct *);
  extern void __delayacct_tsk_exit(struct task_struct *);

  extern void __delayacct_blkio_start(void);
  extern void __delayacct_blkio_end(void);

  extern int __delayacct_add_tsk(struct taskstats *, struct task_struct *);

  extern __u64 __delayacct_blkio_ticks(struct task_struct *);

  extern void __delayacct_freepages_start(void);
  extern void __delayacct_freepages_end(void);

  static inline int delayacct_is_task_waiting_on_io(struct task_struct *p)
  {
  	if (p->delays)
  		return (p->delays->flags & DELAYACCT_PF_BLKIO);
  	else
  		return 0;
  }

  static inline void delayacct_set_flag(int flag)
  {
  	if (current->delays)
  		current->delays->flags |= flag;
  }
  
  static inline void delayacct_clear_flag(int flag)
  {
  	if (current->delays)
  		current->delays->flags &= ~flag;
  }
  
  static inline void delayacct_tsk_init(struct task_struct *tsk)
  {
  	/* reinitialize in case parent's non-null pointer was dup'ed*/
  	tsk->delays = NULL;

  	if (delayacct_on)

  		__delayacct_tsk_init(tsk);
  }

  /* Free tsk->delays. Called from bad fork and __put_task_struct
   * where there's no risk of tsk->delays being accessed elsewhere
   */
  static inline void delayacct_tsk_free(struct task_struct *tsk)

  {
  	if (tsk->delays)

  		kmem_cache_free(delayacct_cache, tsk->delays);
  	tsk->delays = NULL;

  }

  static inline void delayacct_blkio_start(void)
  {

  	delayacct_set_flag(DELAYACCT_PF_BLKIO);

  	if (current->delays)
  		__delayacct_blkio_start();
  }
  
  static inline void delayacct_blkio_end(void)
  {
  	if (current->delays)
  		__delayacct_blkio_end();

  	delayacct_clear_flag(DELAYACCT_PF_BLKIO);

  }

  static inline int delayacct_add_tsk(struct taskstats *d,
  					struct task_struct *tsk)
  {

  	if (!delayacct_on || !tsk->delays)

  		return 0;
  	return __delayacct_add_tsk(d, tsk);
  }

  static inline __u64 delayacct_blkio_ticks(struct task_struct *tsk)
  {
  	if (tsk->delays)
  		return __delayacct_blkio_ticks(tsk);
  	return 0;
  }

  static inline void delayacct_freepages_start(void)
  {
  	if (current->delays)
  		__delayacct_freepages_start();
  }
  
  static inline void delayacct_freepages_end(void)
  {
  	if (current->delays)
  		__delayacct_freepages_end();
  }

  #else
  static inline void delayacct_set_flag(int flag)
  {}
  static inline void delayacct_clear_flag(int flag)
  {}
  static inline void delayacct_init(void)
  {}
  static inline void delayacct_tsk_init(struct task_struct *tsk)
  {}

  static inline void delayacct_tsk_free(struct task_struct *tsk)

  {}

  static inline void delayacct_blkio_start(void)
  {}
  static inline void delayacct_blkio_end(void)
  {}

  static inline int delayacct_add_tsk(struct taskstats *d,
  					struct task_struct *tsk)
  { return 0; }

  static inline __u64 delayacct_blkio_ticks(struct task_struct *tsk)
  { return 0; }

  static inline int delayacct_is_task_waiting_on_io(struct task_struct *p)
  { return 0; }

  static inline void delayacct_freepages_start(void)
  {}
  static inline void delayacct_freepages_end(void)
  {}

  #endif /* CONFIG_TASK_DELAY_ACCT */
  
  #endif