1 files changed, 37 insertions, 0 deletions

diff --git a/include/linux/task_io_accounting.h b/include/linux/task_io_accounting.h
new file mode 100644
index 00000000000..44d00e9ccee
--- /dev/null
+++ b/include/linux/task_io_accounting.h
@@ -0,0 +1,37 @@
+/*
+ * 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