--- /usr/share/man/man5/rc.conf.5.orig	2015-12-02 15:59:11.000000000 +0100
+++ /usr/share/man/man5/rc.conf.5	2016-03-13 20:36:45.000000000 +0100
@@ -331,6 +331,19 @@
 Boolean value.
 Remove block-type swap devices at shutdown time.
 Useful if swapping onto RAIDframe devices.
+.It Sy swap_backed_tmpfs
+A space separated list of filesystem mount points, or
+.Dq "ALL" .
+These tmpfs filesystems will be forcibly unmounted before removing block-type
+swap devices, to avoid having to swap their contents back into RAM.
+The default is
+.Dq "ALL"
+(i.e. unmount all tmpfs filesystems).
+If
+.Pa /dev
+is mounted on tmpfs, then this should be set to an explicit, possibly empty
+list which excludes
+.Pa /dev .
 .El
 .Ss Block device subsystems
 .Bl -tag -width net_interfaces