1 files changed, 45 insertions, 0 deletions
diff --git a/include/linux/task_io_accounting.h b/include/linux/task_io_accounting.h
new file mode 100644
index 000000000..bdf855c28
--- /dev/null
+++ b/include/linux/task_io_accounting.h
@@ -0,0 +1,45 @@
+/*
+ * 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 */
+};