diff --git a/include/sys/vmsystm.h b/include/sys/vmsystm.h
index 929c790d08..e0995c374d 100644
--- a/include/sys/vmsystm.h
+++ b/include/sys/vmsystm.h
@@ -58,7 +58,9 @@ extern vmem_t *zio_alloc_arena;		/* arena for zio caches */
 extern vmem_t *zio_arena;		/* arena for allocating zio memory */
 
 extern pgcnt_t spl_kmem_availrmem(void);
+#if 0
 extern size_t vmem_size(vmem_t *vmp, int typemask);
+#endif
 
 /*
  * The following symbols are available for use within the kernel
diff --git a/module/spl/spl-kmem.c b/module/spl/spl-kmem.c
index b8b006610d..1030cdd8e2 100644
--- a/module/spl/spl-kmem.c
+++ b/module/spl/spl-kmem.c
@@ -118,6 +118,7 @@ spl_kmem_availrmem(void)
 }
 EXPORT_SYMBOL(spl_kmem_availrmem);
 
+#if 0
 size_t
 vmem_size(vmem_t *vmp, int typemask)
 {
@@ -137,6 +138,7 @@ vmem_size(vmem_t *vmp, int typemask)
 	return size;
 }
 EXPORT_SYMBOL(vmem_size);
+#endif
 
 
 /*