PROBLEM:  (CFS.68084)    (Patch ID: TCR160-029)
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If two nodes in a cluster are communicating using the mc-api, for example
running an MPI application, and a third node, not involved in the
calculation, is re-booted then the first two nodes can hang requiring a
re-boot to resolve the hang.

When a node enters or leaves the cluster (boots or shutsdown) the Memory
Channel failover code is invoked. The problem was that the failover code
was attempting to take a high level lock which under certain circumstances
was held by another process and so the mc-api failover code would
wait forever in kernel mode resulting in a system hang. The problem was
fixed by changing mc-api failover take the lower level lock.