diff --git a/src/runtime/malloc.c b/src/runtime/malloc.c
index 52ae3b04c6..6a494eeafb 100644
--- a/src/runtime/malloc.c
+++ b/src/runtime/malloc.c
@@ -170,6 +170,8 @@ SysAlloc(uintptr n)
 void
 SysUnused(void *v, uintptr n)
 {
+	USED(v);
+	USED(n);
 	// TODO(rsc): call madvise MADV_DONTNEED
 }