summaryrefslogtreecommitdiff
path: root/include/linux/task_io_accounting.h
blob: 44d00e9cceea551256df7428be8856e719d04ef1 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
/*
 * 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 akpm@osdl.org 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