src/hotspot/os/posix/os_posix.cpp

*** 1898,1908 ****
    int v;
  
    // atomically decrement _event
    for (;;) {
      v = _event;
!     if (Atomic::cmpxchg(v - 1, &_event, v) == v) break;
    }
    guarantee(v >= 0, "invariant");
  
    if (v == 0) { // Do this the hard way by blocking ...
      int status = pthread_mutex_lock(_mutex);
--- 1898,1908 ----
    int v;
  
    // atomically decrement _event
    for (;;) {
      v = _event;
!     if (Atomic::cmpxchg(&_event, v, v - 1) == v) break;
    }
    guarantee(v >= 0, "invariant");
  
    if (v == 0) { // Do this the hard way by blocking ...
      int status = pthread_mutex_lock(_mutex);
*** 1938,1948 ****
  
    int v;
    // atomically decrement _event
    for (;;) {
      v = _event;
!     if (Atomic::cmpxchg(v - 1, &_event, v) == v) break;
    }
    guarantee(v >= 0, "invariant");
  
    if (v == 0) { // Do this the hard way by blocking ...
      struct timespec abst;
--- 1938,1948 ----
  
    int v;
    // atomically decrement _event
    for (;;) {
      v = _event;
!     if (Atomic::cmpxchg(&_event, v, v - 1) == v) break;
    }
    guarantee(v >= 0, "invariant");
  
    if (v == 0) { // Do this the hard way by blocking ...
      struct timespec abst;
*** 1996,2006 ****
    // shake out uses of park() and unpark() without checking state conditions
    // properly. This spurious return doesn't manifest itself in any user code
    // but only in the correctly written condition checking loops of ObjectMonitor,
    // Mutex/Monitor, Thread::muxAcquire and JavaThread::sleep
  
!   if (Atomic::xchg(1, &_event) >= 0) return;
  
    int status = pthread_mutex_lock(_mutex);
    assert_status(status == 0, status, "mutex_lock");
    int anyWaiters = _nParked;
    assert(anyWaiters == 0 || anyWaiters == 1, "invariant");
--- 1996,2006 ----
    // shake out uses of park() and unpark() without checking state conditions
    // properly. This spurious return doesn't manifest itself in any user code
    // but only in the correctly written condition checking loops of ObjectMonitor,
    // Mutex/Monitor, Thread::muxAcquire and JavaThread::sleep
  
!   if (Atomic::xchg(&_event, 1) >= 0) return;
  
    int status = pthread_mutex_lock(_mutex);
    assert_status(status == 0, status, "mutex_lock");
    int anyWaiters = _nParked;
    assert(anyWaiters == 0 || anyWaiters == 1, "invariant");
*** 2044,2054 ****
  
    // Optional fast-path check:
    // Return immediately if a permit is available.
    // We depend on Atomic::xchg() having full barrier semantics
    // since we are doing a lock-free update to _counter.
!   if (Atomic::xchg(0, &_counter) > 0) return;
  
    Thread* thread = Thread::current();
    assert(thread->is_Java_thread(), "Must be JavaThread");
    JavaThread *jt = (JavaThread *)thread;
  
--- 2044,2054 ----
  
    // Optional fast-path check:
    // Return immediately if a permit is available.
    // We depend on Atomic::xchg() having full barrier semantics
    // since we are doing a lock-free update to _counter.
!   if (Atomic::xchg(&_counter, 0) > 0) return;
  
    Thread* thread = Thread::current();
    assert(thread->is_Java_thread(), "Must be JavaThread");
    JavaThread *jt = (JavaThread *)thread;