Log Message:
-----------
Don't use a non-locked pre-test of the spinlock on x86_64 machines.
The pre-test has been shown to be a big loss on Opterons and at best a
wash on EM64T.
Modified Files:
--------------
pgsql/src/include/storage:
s_lock.h (r1.140 -> r1.141)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/storage/s_lock.h.diff?r1=1.140&r2=1.141)