Methods and devices are provided for controlling lock and unlock operations
within a computer system. A home cluster includes a home lock manager. The home
lock manager is a master lock manager for the home cluster and for a plurality
of remote clusters, the plurality of remote clusters including remote cache coherency
controllers and a plurality of remote processors. Lock and unlock commands from
the home lock manager are transmitted by a home cache coherency controller to the
remote cache coherency controllers and forwarded to the remote processors.