// create and start a new ConcurrentMarkSweep Thread for given CMS generation
ConcurrentMarkSweepThread* ConcurrentMarkSweepThread::start(CMSCollector* collector) {
if (!_should_terminate) {
assert(cmst() == NULL, "start() called twice?");
ConcurrentMarkSweepThread* th = new ConcurrentMarkSweepThread(collector);
assert(cmst() == th, "Where did the just-created CMS thread go?");
return th;
}
return NULL;
}
void ConcurrentMarkSweepThread::run() {
assert(this == cmst(), "just checking");
this->record_stack_base_and_size();
this->initialize_thread_local_storage();
this->set_active_handles(JNIHandleBlock::allocate_block());
// From this time Thread::current() should be working.
assert(this == Thread::current(), "just checking");
if (BindCMSThreadToCPU && !os::bind_to_processor(CPUForCMSThread)) {
warning("Couldn't bind CMS thread to processor %u", CPUForCMSThread);
}
// Wait until Universe::is_fully_initialized()
{
CMSLoopCountWarn loopX("CMS::run", "waiting for "
"Universe::is_fully_initialized()", 2);
MutexLockerEx x(CGC_lock, true);
set_CMS_flag(CMS_cms_wants_token);
// Wait until Universe is initialized and all initialization is completed.
while (!is_init_completed() && !Universe::is_fully_initialized() &&
!_should_terminate) {
CGC_lock->wait(true, 200);
loopX.tick();
}
// Wait until the surrogate locker thread that will do
// pending list locking on our behalf has been created.
// We cannot start the SLT thread ourselves since we need
// to be a JavaThread to do so.
CMSLoopCountWarn loopY("CMS::run", "waiting for SLT installation", 2);
while (_slt == NULL && !_should_terminate) {
CGC_lock->wait(true, 200);
loopY.tick();
}
clear_CMS_flag(CMS_cms_wants_token);
}
while (!_should_terminate) {
sleepBeforeNextCycle();
if (_should_terminate) break;
GCCause::Cause cause = _collector->_full_gc_requested ?
_collector->_full_gc_cause : GCCause::_cms_concurrent_mark;
_collector->collect_in_background(false, cause);
}
assert(_should_terminate, "just checking");
// Check that the state of any protocol for synchronization
// between background (CMS) and foreground collector is "clean"
// (i.e. will not potentially block the foreground collector,
// requiring action by us).
verify_ok_to_terminate();
// Signal that it is terminated
{
MutexLockerEx mu(Terminator_lock,
Mutex::_no_safepoint_check_flag);
assert(_cmst == this, "Weird!");
_cmst = NULL;
Terminator_lock->notify();
}
// Thread destructor usually does this..
ThreadLocalStorage::set_thread(NULL);
}
void ConcurrentMarkSweepThread::stop() {
if (CMSIncrementalMode) {
// Disable incremental mode and wake up the thread so it notices the change.
disable_icms();
start_icms();
}
// it is ok to take late safepoints here, if needed
{
MutexLockerEx x(Terminator_lock);
_should_terminate = true;
}
{ // Now post a notify on CGC_lock so as to nudge
// CMS thread(s) that might be slumbering in
// sleepBeforeNextCycle.
MutexLockerEx x(CGC_lock, Mutex::_no_safepoint_check_flag);
CGC_lock->notify_all();
}
{ // Now wait until (all) CMS thread(s) have exited
MutexLockerEx x(Terminator_lock);
while(cmst() != NULL) {
Terminator_lock->wait();
}
}
}