1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * task_io_accounting: a structure which is used for recording a single task's
4 * IO statistics.
5 *
6 * Don't include this header file directly - it is designed to be dragged in via
7 * sched.h.
8 *
9 * Blame Andrew Morton for all this.
10 */
11
12 struct task_io_accounting {
13 #ifdef CONFIG_TASK_XACCT
14 /* bytes read */
15 u64 rchar;
16 /* bytes written */
17 u64 wchar;
18 /* # of read syscalls */
19 u64 syscr;
20 /* # of write syscalls */
21 u64 syscw;
22 #endif /* CONFIG_TASK_XACCT */
23
24 #ifdef CONFIG_TASK_IO_ACCOUNTING
25 /*
26 * The number of bytes which this task has caused to be read from
27 * storage.
28 */
29 u64 read_bytes;
30
31 /*
32 * The number of bytes which this task has caused, or shall cause to be
33 * written to disk.
34 */
35 u64 write_bytes;
36
37 /*
38 * A task can cause "negative" IO too. If this task truncates some
39 * dirty pagecache, some IO which another task has been accounted for
40 * (in its write_bytes) will not be happening. We _could_ just
41 * subtract that from the truncating task's write_bytes, but there is
42 * information loss in doing that.
43 */
44 u64 cancelled_write_bytes;
45 #endif /* CONFIG_TASK_IO_ACCOUNTING */
46 };