Index: zio.c
===================================================================
--- zio.c	(revision 249894)
+++ zio.c	(working copy)
@@ -155,6 +155,9 @@ zio_init(void)
 	zio_link_cache = kmem_cache_create("zio_link_cache",
 	    sizeof (zio_link_t), 0, NULL, NULL, NULL, NULL, NULL, 0);
 
+	if (!zio_use_uma)
+		goto out;
+
 	/*
 	 * For small buffers, we want a cache for each multiple of
 	 * SPA_MINBLOCKSIZE.  For medium-size buffers, we want a cache
@@ -226,7 +229,7 @@ zio_init(void)
 		zfs_mg_alloc_failures = MAX((3 * max_ncpus / 2), 8);
 	else if (zfs_mg_alloc_failures < 8)
 		zfs_mg_alloc_failures = 8;
-
+out:
 	zio_inject_init();
 
 	zio_trim_ksp = kstat_create("zfs", 0, "zio_trim", "misc",