K 10
svn:author
V 7
attilio
K 8
svn:date
V 27
2010-02-09T14:56:10.302371Z
K 7
svn:log
V 507
MFC r202889, r202940:
- Fix a race in sched_switch() of sched_4bsd.
  Block the td_lock when acquiring explicitly sched_lock in order to prevent
  races with other td_lock contenders.
- Merge the ULE's internal function thread_block_switch() into the global
  thread_lock_block() and make the former semantic as the default for
  thread_lock_block().
- Split out an invariant in order to have better checks.

Tested by:	Giovanni Trematerra
		<giovanni dot trematerra at gmail dot com>
Approved by:	re (kib)

END