This patch series implements asymmetric SMT packing which ensures
consistently good performance on POWER7.  Without this series, tasks
will vary in performance by around +/-30% on POWER7

This new version is based on help from Vatsa and Vaidy in an attempt
to answer concerns that Peter Zijlstra had about the original series.

The 1st patch is a fix for SMT4 in general.
The 2nd adds actual the asymmetrical packing infrastructure.  
The 3rd adds the powerpc specific hooks for POWER7.