Index: kernel/generic/include/mm/frame.h
===================================================================
--- kernel/generic/include/mm/frame.h	(revision d99c1d2ba8c7b2c687d430f2e9fd237046606545)
+++ kernel/generic/include/mm/frame.h	(revision faf38b24fb042fe9f1d90d5bb4cc3c9364782df0)
@@ -170,4 +170,5 @@
 extern void zone_merge_all(void);
 extern uint64_t zone_total_size(void);
+extern void zone_busy_and_free(uint64_t *out_busy, uint64_t *out_free);
 
 /*