diff --git a/sys/vm/uma.h b/sys/vm/uma.h
--- a/sys/vm/uma.h
+++ b/sys/vm/uma.h
@@ -302,6 +302,8 @@
 #define UMA_ALIGN_SHORT	(sizeof(short) - 1)	/* "" short */
 #define UMA_ALIGN_CHAR	(sizeof(char) - 1)	/* "" char */
 #define UMA_ALIGN_CACHE	(uma_get_cache_align_mask()) /* Cache line size align */
+/* Align both to cache line size and an explicit alignment (through mask). */
+#define UMA_ALIGN_CACHE_AND_MASK(mask) (uma_get_cache_align_mask() | (mask))
 #define	UMA_ALIGNOF(type) (_Alignof(type) - 1)	/* Alignment fit for 'type' */
 
 #define	UMA_ANYDOMAIN	-1	/* Special value for domain search. */