diff --git a/include/net/red.h b/include/net/red.h
index d9e1149..0bc1691 100644
--- a/include/net/red.h
+++ b/include/net/red.h
@@ -178,7 +178,7 @@
 	int  shift;
 
 	PSCHED_GET_TIME(now);
-	us_idle = PSCHED_TDIFF_SAFE(now, p->qidlestart, p->Scell_max);
+	us_idle = psched_tdiff_bounded(now, p->qidlestart, p->Scell_max);
 
 	/*
 	 * The problem: ideally, average length queue recalcultion should