#ifndef _LINUX_AVERAGE_H
  #define _LINUX_AVERAGE_H
  
  /* Exponentially weighted moving average (EWMA) */
  
  /* For more documentation see lib/average.c */
  
  struct ewma {
  	unsigned long internal;
  	unsigned long factor;
  	unsigned long weight;
  };
  
  extern void ewma_init(struct ewma *avg, unsigned long factor,
  		      unsigned long weight);
  
  extern struct ewma *ewma_add(struct ewma *avg, unsigned long val);
  
  /**
   * ewma_read() - Get average value
   * @avg: Average structure
   *
   * Returns the average value held in @avg.
   */
  static inline unsigned long ewma_read(const struct ewma *avg)
  {
  	return avg->internal >> avg->factor;
  }
  
  #endif /* _LINUX_AVERAGE_H */