/*

   * task_io_accounting: a structure which is used for recording a single task's

   * IO statistics.
   *
   * Don't include this header file directly - it is designed to be dragged in via
   * sched.h.
   *

   * Blame Andrew Morton for all this.

   */

  struct task_io_accounting {

  #ifdef CONFIG_TASK_XACCT

  	/* bytes read */
  	u64 rchar;
  	/*  bytes written */
  	u64 wchar;
  	/* # of read syscalls */
  	u64 syscr;
  	/* # of write syscalls */
  	u64 syscw;

  #endif /* CONFIG_TASK_XACCT */

  #ifdef CONFIG_TASK_IO_ACCOUNTING

  	/*
  	 * The number of bytes which this task has caused to be read from
  	 * storage.
  	 */
  	u64 read_bytes;
  
  	/*
  	 * The number of bytes which this task has caused, or shall cause to be
  	 * written to disk.
  	 */
  	u64 write_bytes;
  
  	/*
  	 * A task can cause "negative" IO too.  If this task truncates some
  	 * dirty pagecache, some IO which another task has been accounted for
  	 * (in its write_bytes) will not be happening.  We _could_ just
  	 * subtract that from the truncating task's write_bytes, but there is
  	 * information loss in doing that.
  	 */
  	u64 cancelled_write_bytes;

  #endif /* CONFIG_TASK_IO_ACCOUNTING */

  };