From: Nick Piggin <nickpiggin@yahoo.com.au>

Analysis and basic idea from Suresh Siddha <suresh.b.siddha@intel.com>

"This small change in load_balance() brings the performance back upto base
scheduler(infact I see a ~1.5% performance improvement now).  Basically
this fix removes the unnecessary double_lock.."

Workload is SpecJBB on 16-way Altix.