task_io_accounting.h

来自「Axis 221 camera embedded programing inte」· C头文件 代码 · 共 38 行

/*
 * 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 [e-mail] for all this.
 */

#ifdef CONFIG_TASK_IO_ACCOUNTING
struct 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;
};
#else
struct task_io_accounting {
};
#endif