diff --git a/sys/kern/kern_mib.c b/sys/kern/kern_mib.c
index ac6196c50772..f27d01aaa371 100644
--- a/sys/kern/kern_mib.c
+++ b/sys/kern/kern_mib.c
@@ -55,35 +55,35 @@ __FBSDID("$FreeBSD$");
 #include <sys/sx.h>
 #include <sys/unistd.h>
 
-SYSCTL_NODE(, 0,	  sysctl, CTLFLAG_RW, 0,
+SYSCTL_ROOT_NODE(0,	  sysctl, CTLFLAG_RW, 0,
 	"Sysctl internal magic");
-SYSCTL_NODE(, CTL_KERN,	  kern,   CTLFLAG_RW|CTLFLAG_CAPRD, 0,
+SYSCTL_ROOT_NODE(CTL_KERN,	  kern,   CTLFLAG_RW|CTLFLAG_CAPRD, 0,
 	"High kernel, proc, limits &c");
-SYSCTL_NODE(, CTL_VM,	  vm,     CTLFLAG_RW, 0,
+SYSCTL_ROOT_NODE(CTL_VM,	  vm,     CTLFLAG_RW, 0,
 	"Virtual memory");
-SYSCTL_NODE(, CTL_VFS,	  vfs,     CTLFLAG_RW, 0,
+SYSCTL_ROOT_NODE(CTL_VFS,	  vfs,     CTLFLAG_RW, 0,
 	"File system");
-SYSCTL_NODE(, CTL_NET,	  net,    CTLFLAG_RW, 0,
+SYSCTL_ROOT_NODE(CTL_NET,	  net,    CTLFLAG_RW, 0,
 	"Network, (see socket.h)");
-SYSCTL_NODE(, CTL_DEBUG,  debug,  CTLFLAG_RW, 0,
+SYSCTL_ROOT_NODE(CTL_DEBUG,  debug,  CTLFLAG_RW, 0,
 	"Debugging");
 SYSCTL_NODE(_debug, OID_AUTO,  sizeof,  CTLFLAG_RW, 0,
 	"Sizeof various things");
-SYSCTL_NODE(, CTL_HW,	  hw,     CTLFLAG_RW, 0,
+SYSCTL_ROOT_NODE(CTL_HW,	  hw,     CTLFLAG_RW, 0,
 	"hardware");
-SYSCTL_NODE(, CTL_MACHDEP, machdep, CTLFLAG_RW, 0,
+SYSCTL_ROOT_NODE(CTL_MACHDEP, machdep, CTLFLAG_RW, 0,
 	"machine dependent");
-SYSCTL_NODE(, CTL_USER,	  user,   CTLFLAG_RW, 0,
+SYSCTL_ROOT_NODE(CTL_USER,	  user,   CTLFLAG_RW, 0,
 	"user-level");
-SYSCTL_NODE(, CTL_P1003_1B,  p1003_1b,   CTLFLAG_RW, 0,
+SYSCTL_ROOT_NODE(CTL_P1003_1B,  p1003_1b,   CTLFLAG_RW, 0,
 	"p1003_1b, (see p1003_1b.h)");
 
-SYSCTL_NODE(, OID_AUTO,  compat, CTLFLAG_RW, 0,
+SYSCTL_ROOT_NODE(OID_AUTO,  compat, CTLFLAG_RW, 0,
 	"Compatibility code");
-SYSCTL_NODE(, OID_AUTO, security, CTLFLAG_RW, 0, 
+SYSCTL_ROOT_NODE(OID_AUTO, security, CTLFLAG_RW, 0, 
      	"Security");
 #ifdef REGRESSION
-SYSCTL_NODE(, OID_AUTO, regression, CTLFLAG_RW, 0,
+SYSCTL_ROOT_NODE(OID_AUTO, regression, CTLFLAG_RW, 0,
      "Regression test MIB");
 #endif
 
diff --git a/sys/sys/sysctl.h b/sys/sys/sysctl.h
index 45ae3a2e4147..64533e560c18 100644
--- a/sys/sys/sysctl.h
+++ b/sys/sys/sysctl.h
@@ -92,6 +92,7 @@ struct ctlname {
 #define	CTLFLAG_CAPRD	0x00008000	/* Can be read in capability mode */
 #define	CTLFLAG_CAPWR	0x00004000	/* Can be written in capability mode */
 #define	CTLFLAG_STATS	0x00002000	/* Statistics, not a tuneable */
+#define	CTLFLAG_NOFETCH	0x00001000	/* Don't fetch tunable from getenv() */
 #define	CTLFLAG_CAPRW	(CTLFLAG_CAPRD|CTLFLAG_CAPWR)
 
 /*
@@ -206,6 +207,7 @@ void sysctl_unregister_oid(struct sysctl_oid *oidp);
 /* Hide these in macros. */
 #define	SYSCTL_CHILDREN(oid_ptr)					\
 	(struct sysctl_oid_list *)(oid_ptr)->oid_arg1
+#define	SYSCTL_PARENT(oid_ptr)			NULL	/* not supported */
 #define	SYSCTL_CHILDREN_SET(oid_ptr, val)	(oid_ptr)->oid_arg1 = (val)
 #define	SYSCTL_STATIC_CHILDREN(oid_name)	(&sysctl_##oid_name##_children)
 
@@ -296,12 +298,19 @@ SYSCTL_ALLOWED_TYPES(UINT64, uint64_t *a; unsigned long long *b; );
 #define	SYSCTL_ADD_OID(ctx, parent, nbr, name, kind, a1, a2, handler, fmt, descr) \
 	sysctl_add_oid(ctx, parent, nbr, name, kind, a1, a2, handler, fmt, __DESCR(descr))
 
+/* This constructs a root node from which other nodes can hang. */
+#define	SYSCTL_ROOT_NODE(nbr, name, access, handler, descr)		\
+	SYSCTL_NODE(, nbr, name, access, handler, descr)
+
 /* This constructs a node from which other oids can hang. */
 #define	SYSCTL_NODE(parent, nbr, name, access, handler, descr)		    \
 	struct sysctl_oid_list SYSCTL_NODE_CHILDREN(parent, name);	    \
 	SYSCTL_OID(parent, nbr, name, CTLTYPE_NODE|(access),		    \
 	    (void*)&SYSCTL_NODE_CHILDREN(parent, name), 0, handler, "N", descr)
 
+#define	SYSCTL_ADD_ROOT_NODE(ctx, nbr, name, access, handler, descr) \
+	SYSCTL_ADD_NODE(ctx, SYSCTL_STATIC_CHILDREN(), nbr, name, access, handler, descr)
+
 #define	SYSCTL_ADD_NODE(ctx, parent, nbr, name, access, handler, descr)	    \
 	sysctl_add_oid(ctx, parent, nbr, name, CTLTYPE_NODE|(access),	    \
 	NULL, 0, handler, "N", __DESCR(descr))