diff --git a/sys/amd64/include/vmparam.h b/sys/amd64/include/vmparam.h
index d90dd78bbbf3..d76be9452ba3 100644
--- a/sys/amd64/include/vmparam.h
+++ b/sys/amd64/include/vmparam.h
@@ -133,7 +133,7 @@
  * Ceiling on amount of kmem_map kva space.
  */
 #ifndef VM_KMEM_SIZE_MAX
-#define	VM_KMEM_SIZE_MAX	(200 * 1024 * 1024)
+#define	VM_KMEM_SIZE_MAX	(400 * 1024 * 1024)
 #endif
 
 /* initial pagein size of beginning of executable file */