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src/hotspot/share/runtime/objectMonitor.inline.hpp
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rev 54110 : Checkpoint latest preliminary review patches for full OpenJDK review.
@@ -51,24 +51,44 @@
inline jint ObjectMonitor::waiters() const {
return _waiters;
}
+// Returns NULL if DEFLATER_MARKER is observed.
inline void* ObjectMonitor::owner() const {
- return _owner;
+ void* owner = _owner;
+ return owner != DEFLATER_MARKER ? owner : NULL;
}
inline void ObjectMonitor::clear() {
- assert(_header != NULL, "Fatal logic error in ObjectMonitor header!");
assert(_count == 0, "Fatal logic error in ObjectMonitor count!");
+ assert(_owner == NULL, "Fatal logic error in ObjectMonitor owner!");
+
+ clear_using_JT();
+}
+
+inline void ObjectMonitor::clear_using_JT() {
+ // When clearing using a JavaThread, we leave _owner == DEFLATER_MARKER
+ // and _count < 0 to force any racing threads to retry. Unlike other
+ // *_using_JT() functions, we cannot assert AsyncDeflateIdleMonitors
+ // or Thread::current()->is_Java_thread() because clear() calls this
+ // function for the rest of its checks.
+
+ assert(_header != NULL, "Fatal logic error in ObjectMonitor header!");
assert(_waiters == 0, "Fatal logic error in ObjectMonitor waiters!");
assert(_recursions == 0, "Fatal logic error in ObjectMonitor recursions!");
assert(_object != NULL, "Fatal logic error in ObjectMonitor object!");
- assert(_owner == NULL, "Fatal logic error in ObjectMonitor owner!");
+ // Do not assert _ref_count == 0 here because a racing thread could
+ // increment _ref_count, observe _owner == DEFLATER_MARKER and then
+ // decrement _ref_count.
+ set_allocation_state(Free);
_header = NULL;
_object = NULL;
+ // Do not clear _ref_count here because _ref_count is for indicating
+ // that the ObjectMonitor* is in use which is orthogonal to whether
+ // the ObjectMonitor itself is in use for a locking operation.
}
inline void* ObjectMonitor::object() const {
return _object;
}
@@ -105,6 +125,61 @@
inline void ObjectMonitor::set_owner(void* owner) {
_owner = owner;
_recursions = 0;
}
+inline void ObjectMonitor::set_allocation_state(ObjectMonitor::AllocationState s) {
+ _allocation_state = s;
+}
+
+inline ObjectMonitor::AllocationState ObjectMonitor::allocation_state() const {
+ return _allocation_state;
+}
+
+inline bool ObjectMonitor::is_free() const {
+ return _allocation_state == Free;
+}
+
+inline bool ObjectMonitor::is_active() const {
+ return !is_free();
+}
+
+inline bool ObjectMonitor::is_old() const {
+ return _allocation_state == Old;
+}
+
+inline bool ObjectMonitor::is_new() const {
+ return _allocation_state == New;
+}
+
+inline void ObjectMonitor::dec_ref_count() {
+ // The decrement needs to be MO_ACQ_REL. At the moment, the Atomic::dec
+ // backend on PPC does not yet conform to these requirements. Therefore
+ // the decrement is simulated with an Atomic::sub(1, &addr). Without
+ // this MO_ACQ_REL Atomic::dec simulation, AsyncDeflateIdleMonitors is
+ // not safe.
+ Atomic::sub((jint)1, &_ref_count);
+ guarantee(_ref_count >= 0, "sanity check: ref_count=%d", _ref_count);
+}
+
+inline void ObjectMonitor::inc_ref_count() {
+ // The increment needs to be MO_SEQ_CST. At the moment, the Atomic::inc
+ // backend on PPC does not yet conform to these requirements. Therefore
+ // the increment is simulated with a load phi; cas phi + 1; loop.
+ // Without this MO_SEQ_CST Atomic::inc simulation, AsyncDeflateIdleMonitors
+ // is not safe.
+ for (;;) {
+ jint sample = OrderAccess::load_acquire(&_ref_count);
+ guarantee(sample >= 0, "sanity check: sample=%d", (int)sample);
+ if (Atomic::cmpxchg(sample + 1, &_ref_count, sample) == sample) {
+ // Incremented _ref_count without interference.
+ return;
+ }
+ // Implied else: Saw interference so loop and try again.
+ }
+}
+
+inline jint ObjectMonitor::ref_count() const {
+ return OrderAccess::load_acquire(&_ref_count);
+}
+
#endif // SHARE_RUNTIME_OBJECTMONITOR_INLINE_HPP
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