syslet engine: smart batching

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/fio.h b/fio.h
index f2366c4..57d1b6b 100644
--- a/fio.h
+++ b/fio.h
@@ -81,8 +81,9 @@
 
 #ifdef FIO_HAVE_SYSLET
 struct syslet_req {
-	struct syslet_uatom atom;
-	long ret;
+	struct syslet_uatom atom;	/* the atom to submit */
+	struct syslet_uatom *head;	/* head of the sequence */
+	long ret;			/* syscall return value */
 };
 #endif