diff --git a/src/libstd/thread/mod.rs b/src/libstd/thread/mod.rs index a7c7dbb1b40..020ea09db2a 100644 --- a/src/libstd/thread/mod.rs +++ b/src/libstd/thread/mod.rs @@ -800,7 +800,7 @@ pub fn park() { match thread.inner.state.compare_exchange(EMPTY, PARKED, SeqCst, SeqCst) { Ok(_) => {} Err(NOTIFIED) => { - thread.inner.state.store(EMPTY, SeqCst); + thread.inner.state.swap(EMPTY, SeqCst); return; } // should consume this notification, so prohibit spurious wakeups in next park. Err(_) => panic!("inconsistent park state"), @@ -889,7 +889,7 @@ pub fn park_timeout(dur: Duration) { match thread.inner.state.compare_exchange(EMPTY, PARKED, SeqCst, SeqCst) { Ok(_) => {} Err(NOTIFIED) => { - thread.inner.state.store(EMPTY, SeqCst); + thread.inner.state.swap(EMPTY, SeqCst); return; } // should consume this notification, so prohibit spurious wakeups in next park. Err(_) => panic!("inconsistent park_timeout state"), @@ -1058,23 +1058,16 @@ impl Thread { /// [park]: fn.park.html #[stable(feature = "rust1", since = "1.0.0")] pub fn unpark(&self) { - loop { - match self.inner.state.compare_exchange(EMPTY, NOTIFIED, SeqCst, SeqCst) { - Ok(_) => return, // no one was waiting - Err(NOTIFIED) => return, // already unparked - Err(PARKED) => {} // gotta go wake someone up - _ => panic!("inconsistent state in unpark"), - } - - // Coordinate wakeup through the mutex and a condvar notification - let _lock = self.inner.lock.lock().unwrap(); - match self.inner.state.compare_exchange(PARKED, NOTIFIED, SeqCst, SeqCst) { - Ok(_) => return self.inner.cvar.notify_one(), - Err(NOTIFIED) => return, // a different thread unparked - Err(EMPTY) => {} // parked thread went away, try again - _ => panic!("inconsistent state in unpark"), - } + match self.inner.state.swap(NOTIFIED, SeqCst) { + EMPTY => return, // no one was waiting + NOTIFIED => return, // already unparked + PARKED => {} // gotta go wake someone up + _ => panic!("inconsistent state in unpark"), } + + // Coordinate wakeup through the mutex and a condvar notification + let _lock = self.inner.lock.lock().unwrap(); + self.inner.cvar.notify_one() } /// Gets the thread's unique identifier.