Function DmtcpMutexTryLock

src/mutex.cpp:76–104

extern "C" int
DmtcpMutexTryLock(DmtcpMutex *mutex)
{
  pid_t owner = 1;

  if (mutex->type != DMTCP_MUTEX_LLL) {
    owner = gettid();

    if ((pid_t)(mutex->owner) == owner) {
      if (mutex->type == DMTCP_MUTEX_RECURSIVE) {
        JASSERT(mutex->count + 1 != 0);
        mutex->count++;
        return 0;
      }
      return EDEADLK;
    }
  }

  if (__sync_val_compare_and_swap(&mutex->futex,
                                   LOCK_FREE,
                                   LOCK_ACQUIRED) == LOCK_FREE) {
    // We successfully acquired the lock.
    mutex->owner = (mutex_owner_t)owner;
    mutex->count = 1;
    return 0;
  }

  return EAGAIN;
}


/* Set mutex->futex to 0 (LOCK_FREE), releasing the lock. If mutex->futex was