K 10
svn:author
V 7
davidxu
K 8
svn:date
V 27
2012-03-21T07:21:05.947543Z
K 7
svn:log
V 311
Use version 2 of semaphore provided by kernel umtx code, now if there is
no waiters, we still increase and decrease count in user mode, once there
is a waiter, sem_post will enter kernel to increase count and wake thread
up, this is atomicy and allow us to gracefully destroy semaphore after
sem_wait returned.

END