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Andrew Morton7c3ab732006-12-10 02:19:19 -08001/*
2 * task_io_accounting: a structure which is used for recording a single task's
3 * IO statistics.
4 *
5 * Don't include this header file directly - it is designed to be dragged in via
6 * sched.h.
7 *
8 * Blame akpm@osdl.org for all this.
9 */
10
11#ifdef CONFIG_TASK_IO_ACCOUNTING
12struct task_io_accounting {
13 /*
14 * The number of bytes which this task has caused to be read from
15 * storage.
16 */
17 u64 read_bytes;
18
19 /*
20 * The number of bytes which this task has caused, or shall cause to be
21 * written to disk.
22 */
23 u64 write_bytes;
24
25 /*
26 * A task can cause "negative" IO too. If this task truncates some
27 * dirty pagecache, some IO which another task has been accounted for
28 * (in its write_bytes) will not be happening. We _could_ just
29 * subtract that from the truncating task's write_bytes, but there is
30 * information loss in doing that.
31 */
32 u64 cancelled_write_bytes;
33};
34#else
35struct task_io_accounting {
36};
37#endif