difference). You need this patch on top of latest ckdev for the cpu nice
value to be inherited properly for io priorities, otherwise only
directly set io priorities work:

--- linux-2.6.10-ckdev/drivers/block/cfq-iosched.c~	2004-12-30 18:30:09.672819232 +0100
+++ linux-2.6.10-ckdev/drivers/block/cfq-iosched.c	2004-12-30 18:30:20.566163192 +0100
@@ -1383,8 +1383,8 @@
 			/*
 			 * no prio set, place us in the middle of the BE classes
 			 */
+			cfqq->ioprio = task_ioprio(current);
 			cfqq->ioprio_class = IOPRIO_CLASS_BE;
-			cfqq->ioprio = 4;
 			break;
 		case IOPRIO_CLASS_RT:
 			cfqq->ioprio_class = IOPRIO_CLASS_RT;