diff --git a/libexec/rc/rc.conf b/libexec/rc/rc.conf
--- a/libexec/rc/rc.conf
+++ b/libexec/rc/rc.conf
@@ -122,6 +122,8 @@
 background_fsck="YES"	# Attempt to run fsck in the background where possible.
 background_fsck_delay="60" # Time to wait (seconds) before starting the fsck.
 growfs_enable="NO"	# Set to YES to attempt to grow the root filesystem on boot
+growfs_swap_size=""	# Set to 0 to disable growfs swap, "" to default size,
+			# size in bytes to specify swap size.
 netfs_types="nfs:NFS smbfs:SMB" # Net filesystems.
 extra_netfs_types="NO"	# List of network extra filesystem types for delayed
 			# mount at startup (or NO).