diff --git a/sys/kern/vfs_cache.c b/sys/kern/vfs_cache.c
--- a/sys/kern/vfs_cache.c
+++ b/sys/kern/vfs_cache.c
@@ -405,8 +405,6 @@
     "Name cache parameters");
 
 static u_int __read_mostly	ncsize; /* the size as computed on creation or resizing */
-SYSCTL_UINT(_vfs_cache_param, OID_AUTO, size, CTLFLAG_RW, &ncsize, 0,
-    "Total namecache capacity");
 
 u_int ncsizefactor = 2;
 SYSCTL_UINT(_vfs_cache_param, OID_AUTO, sizefactor, CTLFLAG_RW, &ncsizefactor, 0,
@@ -1021,6 +1019,29 @@
     CTLTYPE_INT | CTLFLAG_MPSAFE | CTLFLAG_RW, NULL, 0, sysctl_negminpct,
     "I", "Negative entry \% of namecache capacity above which automatic eviction is allowed");
 
+static int
+sysctl_ncsize(SYSCTL_HANDLER_ARGS)
+{
+	u_int val;
+	int error;
+
+	val = ncsize;
+	error = sysctl_handle_int(oidp, &val, 0, req);
+	if (error != 0 || req->newptr == NULL)
+		return (error);
+
+	if (val == ncsize)
+		return (0);
+
+	ncsize = val;
+	cache_recalc_neg_min();
+	return (0);
+}
+
+SYSCTL_PROC(_vfs_cache_param, OID_AUTO, size,
+    CTLTYPE_INT | CTLFLAG_MPSAFE | CTLFLAG_RW, NULL, 0, sysctl_ncsize,
+    "I", "Total namecache capacity");
+
 #ifdef DEBUG_CACHE
 /*
  * Grab an atomic snapshot of the name cache hash chain lengths