diff --git a/sys/fs/nullfs/null_subr.c b/sys/fs/nullfs/null_subr.c
--- a/sys/fs/nullfs/null_subr.c
+++ b/sys/fs/nullfs/null_subr.c
@@ -41,6 +41,7 @@
 #include <sys/mount.h>
 #include <sys/proc.h>
 #include <sys/vnode.h>
+#include <sys/sysctl.h>
 
 #include <fs/nullfs/null.h>
 
@@ -63,6 +64,10 @@
 
 static void null_hashins(struct mount *, struct null_node *);
 
+SYSCTL_DECL(_vfs);
+
+SYSCTL_NODE(_vfs, OID_AUTO, nullfs, CTLFLAG_RW, 0, "nullfs");
+
 /*
  * Initialise cache headers
  */
diff --git a/sys/fs/nullfs/null_vfsops.c b/sys/fs/nullfs/null_vfsops.c
--- a/sys/fs/nullfs/null_vfsops.c
+++ b/sys/fs/nullfs/null_vfsops.c
@@ -48,6 +48,7 @@
 #include <sys/proc.h>
 #include <sys/vnode.h>
 #include <sys/jail.h>
+#include <sys/sysctl.h>
 
 #include <fs/nullfs/null.h>
 
@@ -63,6 +64,12 @@
 static vfs_vget_t	nullfs_vget;
 static vfs_extattrctl_t	nullfs_extattrctl;
 
+SYSCTL_DECL(_vfs_nullfs);
+
+static bool null_cache_nodes = true;
+SYSCTL_BOOL(_vfs_nullfs, OID_AUTO, cache_nodes, CTLFLAG_RW,
+	&null_cache_nodes, 0, "cache free nullfs vnodes");
+
 /*
  * Mount null layer
  */
@@ -89,6 +96,9 @@
 	if (mp->mnt_flag & MNT_UPDATE) {
 		/*
 		 * Only support update mounts for NFS export.
+		 *
+		 * XXX nocache should also be updated for the tuning of the nullfs
+		 * vnode caching on the fly.
 		 */
 		if (vfs_flagopt(mp->mnt_optnew, "export", NULL, 0))
 			return (0);
@@ -197,10 +207,12 @@
 		MNT_IUNLOCK(mp);
 	}
 
-	xmp->nullm_flags |= NULLM_CACHE;
-	if (vfs_getopt(mp->mnt_optnew, "nocache", NULL, NULL) == 0 ||
-	    (xmp->nullm_vfs->mnt_kern_flag & MNTK_NULL_NOCACHE) != 0)
-		xmp->nullm_flags &= ~NULLM_CACHE;
+	if (null_cache_nodes) {
+		xmp->nullm_flags |= NULLM_CACHE;
+		if (vfs_getopt(mp->mnt_optnew, "nocache", NULL, NULL) == 0 ||
+			(xmp->nullm_vfs->mnt_kern_flag & MNTK_NULL_NOCACHE) != 0)
+			xmp->nullm_flags &= ~NULLM_CACHE;
+	}
 
 	if ((xmp->nullm_flags & NULLM_CACHE) != 0) {
 		vfs_register_for_notification(xmp->nullm_vfs, mp,