diff --git a/include/sys/param.h b/include/sys/param.h
index f924006efa..d6b4f761f3 100644
--- a/include/sys/param.h
+++ b/include/sys/param.h
@@ -1,4 +1,8 @@
 #ifndef _SPL_PARAM_H
 #define _SPL_PARAM_H
 
+/* Pages to bytes and back */
+#define ptob(pages)			(pages * PAGE_SIZE)
+#define btop(bytes)			(bytes / PAGE_SIZE)
+
 #endif /* SPL_PARAM_H */
diff --git a/include/sys/vmsystm.h b/include/sys/vmsystm.h
index 75ae8a9914..c75d447d94 100644
--- a/include/sys/vmsystm.h
+++ b/include/sys/vmsystm.h
@@ -40,7 +40,6 @@
  * memory state and not as direct evidence that page reclaimation
  * is or is not currently in progress.
  */
-#define ptob(pages)			(pages * PAGE_SIZE)
 #define membar_producer()		smp_wmb()
 
 #define physmem				num_physpages