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8222295: more baseline cleanups from Async Monitor Deflation project

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Reviewed-by: coleenp, acorn, dholmes
This commit is contained in:
Daniel D. Daugherty 2019-04-24 10:20:25 -04:00
parent ad207e278d
commit baf1349a2f
8 changed files with 84 additions and 87 deletions
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20
src/hotspot/share/runtime/objectMonitor.cpp
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@ -276,9 +276,13 @@ void ObjectMonitor::enter(TRAPS) {
// Note that if we acquire the monitor from an initial spin
// we forgo posting JVMTI events and firing DTRACE probes.
if (TrySpin(Self) > 0) {
assert(_owner == Self, "invariant");
assert(_recursions == 0, "invariant");
assert(((oop)(object()))->mark() == markOopDesc::encode(this), "invariant");
assert(_owner == Self, "must be Self: owner=" INTPTR_FORMAT, p2i(_owner));
assert(_recursions == 0, "must be 0: recursions=" INTPTR_FORMAT,
_recursions);
assert(((oop)object())->mark() == markOopDesc::encode(this),
"object mark must match encoded this: mark=" INTPTR_FORMAT
", encoded this=" INTPTR_FORMAT, p2i(((oop)object())->mark()),
p2i(markOopDesc::encode(this)));
Self->_Stalled = 0;
return;
}
@ -290,11 +294,11 @@ void ObjectMonitor::enter(TRAPS) {
assert(!SafepointSynchronize::is_at_safepoint(), "invariant");
assert(jt->thread_state() != _thread_blocked, "invariant");
assert(this->object() != NULL, "invariant");
assert(_count >= 0, "invariant");
assert(_contentions >= 0, "invariant");
// Prevent deflation at STW-time. See deflate_idle_monitors() and is_busy().
// Ensure the object-monitor relationship remains stable while there's contention.
Atomic::inc(&_count);
Atomic::inc(&_contentions);
JFR_ONLY(JfrConditionalFlushWithStacktrace<EventJavaMonitorEnter> flush(jt);)
EventJavaMonitorEnter event;
@ -355,8 +359,8 @@ void ObjectMonitor::enter(TRAPS) {
// acquire it.
}
Atomic::dec(&_count);
assert(_count >= 0, "invariant");
Atomic::dec(&_contentions);
assert(_contentions >= 0, "invariant");
Self->_Stalled = 0;
// Must either set _recursions = 0 or ASSERT _recursions == 0.
@ -809,7 +813,7 @@ void ObjectMonitor::UnlinkAfterAcquire(Thread *Self, ObjectWaiter *SelfNode) {
// There's one exception to the claim above, however. EnterI() can call
// exit() to drop a lock if the acquirer has been externally suspended.
// In that case exit() is called with _thread_state as _thread_blocked,
// but the monitor's _count field is > 0, which inhibits reclamation.
// but the monitor's _contentions field is > 0, which inhibits reclamation.
//
// 1-0 exit
// ~~~~~~~~