Index: kernel/generic/include/lib/ra.h
===================================================================
--- kernel/generic/include/lib/ra.h	(revision 961c0484519f4f59bbfc17feda26b91c8046c90a)
+++ kernel/generic/include/lib/ra.h	(revision 12cb03dd6e73558b6ca75313281ad3e66041b239)
@@ -58,4 +58,6 @@
 } ra_span_t;
 
+#define RA_SEGMENT_FREE		1
+
 /*
  * We would like to achieve a good ratio of the size of one unit of the
@@ -70,4 +72,5 @@
 
 	uintptr_t base;		/**< Segment base. */
+	uint8_t flags;		/**< Segment flags. */
 } ra_segment_t;