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8220774: Add HandshakeALot diag option

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Reviewed-by: dcubed, dholmes
This commit is contained in:
Robbin Ehn 2019-03-26 12:08:51 +01:00
parent afa3178149
commit ed3542d53b
10 changed files with 171 additions and 125 deletions
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73
src/hotspot/share/runtime/vmThread.cpp
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@ -434,22 +434,35 @@ void VMThread::evaluate_operation(VM_Operation* op) {
static VM_None safepointALot_op("SafepointALot");
static VM_Cleanup cleanup_op;
VM_Operation* VMThread::no_op_safepoint(bool check_time) {
class HandshakeALotTC : public ThreadClosure {
public:
virtual void do_thread(Thread* thread) {
#ifdef ASSERT
assert(thread->is_Java_thread(), "must be");
JavaThread* jt = (JavaThread*)thread;
jt->verify_states_for_handshake();
#endif
}
};
VM_Operation* VMThread::no_op_safepoint() {
// Check for handshakes first since we may need to return a VMop.
if (HandshakeALot) {
HandshakeALotTC haltc;
Handshake::execute(&haltc);
}
// Check for a cleanup before SafepointALot to keep stats correct.
long interval_ms = SafepointTracing::time_since_last_safepoint_ms();
bool max_time_exceeded = GuaranteedSafepointInterval != 0 &&
(interval_ms >= GuaranteedSafepointInterval);
if (max_time_exceeded && SafepointSynchronize::is_cleanup_needed()) {
return &cleanup_op;
}
if (SafepointALot) {
return &safepointALot_op;
}
if (!SafepointSynchronize::is_cleanup_needed()) {
return NULL;
}
if (check_time) {
long interval_ms = SafepointTracing::time_since_last_safepoint_ms();
bool max_time_exceeded = GuaranteedSafepointInterval != 0 &&
(interval_ms > GuaranteedSafepointInterval);
if (!max_time_exceeded) {
return NULL;
}
}
return &cleanup_op;
// Nothing to be done.
return NULL;
}
void VMThread::loop() {
@ -491,19 +504,22 @@ void VMThread::loop() {
exit(-1);
}
if (timedout && (_cur_vm_operation = VMThread::no_op_safepoint(false)) != NULL) {
MutexUnlockerEx mul(VMOperationQueue_lock,
Mutex::_no_safepoint_check_flag);
// Force a safepoint since we have not had one for at least
// 'GuaranteedSafepointInterval' milliseconds. This will run all
// the clean-up processing that needs to be done regularly at a
// safepoint
SafepointSynchronize::begin();
#ifdef ASSERT
if (timedout) {
// Have to unlock VMOperationQueue_lock just in case no_op_safepoint()
// has to do a handshake.
MutexUnlockerEx mul(VMOperationQueue_lock, Mutex::_no_safepoint_check_flag);
if ((_cur_vm_operation = VMThread::no_op_safepoint()) != NULL) {
// Force a safepoint since we have not had one for at least
// 'GuaranteedSafepointInterval' milliseconds and we need to clean
// something. This will run all the clean-up processing that needs
// to be done at a safepoint.
SafepointSynchronize::begin();
#ifdef ASSERT
if (GCALotAtAllSafepoints) InterfaceSupport::check_gc_alot();
#endif
SafepointSynchronize::end();
_cur_vm_operation = NULL;
#endif
SafepointSynchronize::end();
_cur_vm_operation = NULL;
}
}
_cur_vm_operation = _vm_queue->remove_next();
@ -615,10 +631,9 @@ void VMThread::loop() {
VMOperationRequest_lock->notify_all();
}
//
// We want to make sure that we get to a safepoint regularly.
//
if ((_cur_vm_operation = VMThread::no_op_safepoint(false)) != NULL) {
// We want to make sure that we get to a safepoint regularly
// even when executing VMops that don't require safepoints.
if ((_cur_vm_operation = VMThread::no_op_safepoint()) != NULL) {
HandleMark hm(VMThread::vm_thread());
SafepointSynchronize::begin();
SafepointSynchronize::end();