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8049304: race between VM_Exit and _sync_FutileWakeups->inc()

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Add PerfDataManager.has_PerfData() to indicate when PerfData objects should be safe to query. Update Java monitor PerfData usage to check the new flag. PerfDataManager::destroy() should only be called at a safepoint and when the StatSampler is not active.

Reviewed-by: kbarrett, dholmes, tbenson, bdelsart
This commit is contained in:
Daniel D. Daugherty 2015-09-03 10:22:39 -07:00
parent c091c7348a
commit 9b12926ed8
6 changed files with 57 additions and 39 deletions
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28
hotspot/src/share/vm/runtime/objectMonitor.cpp
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@ -405,9 +405,7 @@ void NOINLINE ObjectMonitor::enter(TRAPS) {
event.commit();
}
if (ObjectMonitor::_sync_ContendedLockAttempts != NULL) {
ObjectMonitor::_sync_ContendedLockAttempts->inc();
}
OM_PERFDATA_OP(ContendedLockAttempts, inc());
}
@ -574,9 +572,9 @@ void NOINLINE ObjectMonitor::EnterI(TRAPS) {
// That is by design - we trade "lossy" counters which are exposed to
// races during updates for a lower probe effect.
TEVENT(Inflated enter - Futile wakeup);
if (ObjectMonitor::_sync_FutileWakeups != NULL) {
ObjectMonitor::_sync_FutileWakeups->inc();
}
// This PerfData object can be used in parallel with a safepoint.
// See the work around in PerfDataManager::destroy().
OM_PERFDATA_OP(FutileWakeups, inc());
++nWakeups;
// Assuming this is not a spurious wakeup we'll normally find _succ == Self.
@ -748,9 +746,9 @@ void NOINLINE ObjectMonitor::ReenterI(Thread * Self, ObjectWaiter * SelfNode) {
// *must* retry _owner before parking.
OrderAccess::fence();
if (ObjectMonitor::_sync_FutileWakeups != NULL) {
ObjectMonitor::_sync_FutileWakeups->inc();
}
// This PerfData object can be used in parallel with a safepoint.
// See the work around in PerfDataManager::destroy().
OM_PERFDATA_OP(FutileWakeups, inc());
}
// Self has acquired the lock -- Unlink Self from the cxq or EntryList .
@ -1302,9 +1300,7 @@ void ObjectMonitor::ExitEpilog(Thread * Self, ObjectWaiter * Wakee) {
Trigger->unpark();
// Maintain stats and report events to JVMTI
if (ObjectMonitor::_sync_Parks != NULL) {
ObjectMonitor::_sync_Parks->inc();
}
OM_PERFDATA_OP(Parks, inc());
}
@ -1765,9 +1761,7 @@ void ObjectMonitor::notify(TRAPS) {
}
DTRACE_MONITOR_PROBE(notify, this, object(), THREAD);
INotify(THREAD);
if (ObjectMonitor::_sync_Notifications != NULL) {
ObjectMonitor::_sync_Notifications->inc(1);
}
OM_PERFDATA_OP(Notifications, inc(1));
}
@ -1792,9 +1786,7 @@ void ObjectMonitor::notifyAll(TRAPS) {
INotify(THREAD);
}
if (tally != 0 && ObjectMonitor::_sync_Notifications != NULL) {
ObjectMonitor::_sync_Notifications->inc(tally);
}
OM_PERFDATA_OP(Notifications, inc(tally));
}
// -----------------------------------------------------------------------------