void WorkGangBarrierSync::enter() {
MutexLockerEx x(monitor(), Mutex::_no_safepoint_check_flag);
if (should_reset()) {
// The should_reset() was set and we are the first worker to enter
// the sync barrier. We will zero the n_completed() count which
// effectively resets the barrier.
zero_completed();
set_should_reset(false);
}
inc_completed();
if (n_completed() == n_workers()) {
// At this point we would like to reset the barrier to be ready in
// case it is used again. However, we cannot set n_completed() to
// 0, even after the notify_all(), given that some other workers
// might still be waiting for n_completed() to become ==
// n_workers(). So, if we set n_completed() to 0, those workers
// will get stuck (as they will wake up, see that n_completed() !=
// n_workers() and go back to sleep). Instead, we raise the
// should_reset() flag and the barrier will be reset the first
// time a worker enters it again.
set_should_reset(true);
monitor()->notify_all();
} else {
while (n_completed() != n_workers()) {
monitor()->wait(/* no_safepoint_check */ true);
}
}
}
void WorkGangBarrierSync::enter() {
MutexLockerEx x(monitor(), Mutex::_no_safepoint_check_flag);
inc_completed();
if (n_completed() == n_workers()) {
monitor()->notify_all();
}
else {
while (n_completed() != n_workers()) {
monitor()->wait(/* no_safepoint_check */ true);
}
}
}