+ hierarchies.</para>
+
+ <para>Note that this option is only
+ applied once, at very early boot. If
+ you use an initial RAM disk (initrd)
+ that uses systemd it might hence be
+ necessary to rebuild the initrd if
+ this option is changed, and make sure
+ the new configuration file is included
+ in it. Otherwise the initrd might
+ mount the controller hierachies in a
+ different configuration than intended,
+ and the main system cannot remount
+ them anymore.</para></listitem>