--- old/src/hotspot/share/runtime/objectMonitor.inline.hpp	2020-02-03 17:39:26.000000000 -0500
+++ new/src/hotspot/share/runtime/objectMonitor.inline.hpp	2020-02-03 17:39:25.000000000 -0500
@@ -52,19 +52,57 @@
   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;
+}
+
+// Returns true if owner field == DEFLATER_MARKER and false otherwise.
+// This accessor is called when we really need to know if the owner
+// field == DEFLATER_MARKER and any non-NULL value won't do the trick.
+inline bool ObjectMonitor::owner_is_DEFLATER_MARKER() {
+  return _owner == DEFLATER_MARKER;
 }
 
 inline void ObjectMonitor::clear() {
   assert(Atomic::load(&_header).value() != 0, "must be non-zero");
+  assert(_owner == NULL, "must be NULL: owner=" INTPTR_FORMAT, p2i(_owner));
+#ifdef ASSERT
+  jint l_ref_count = ref_count();
+#endif
+  assert(l_ref_count == 0, "must be 0: l_ref_count=%d, ref_count=%d", l_ref_count, ref_count());
+
+  Atomic::store(&_header, markWord::zero());
+
+  clear_using_JT();
+}
+
+inline void ObjectMonitor::clear_using_JT() {
+  // 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.
+
+  if (AsyncDeflateIdleMonitors) {
+    // Async deflation protocol uses the header, owner and ref_count
+    // fields. While the ObjectMonitor being deflated is on the global free
+    // list, we leave those three fields alone; owner == DEFLATER_MARKER
+    // and ref_count < 0 will force any racing threads to retry. The
+    // header field is used by install_displaced_markword_in_object()
+    // in the last part of the deflation protocol so we cannot check
+    // its value here.
+    guarantee(_owner == NULL || _owner == DEFLATER_MARKER,
+              "must be NULL or DEFLATER_MARKER: owner=" INTPTR_FORMAT,
+              p2i(_owner));
+    jint l_ref_count = ref_count();
+    guarantee(l_ref_count <= 0, "must be <= 0: l_ref_count=%d, ref_count=%d", l_ref_count, ref_count());
+  }
   assert(_contentions == 0, "must be 0: contentions=%d", _contentions);
   assert(_waiters == 0, "must be 0: waiters=%d", _waiters);
   assert(_recursions == 0, "must be 0: recursions=" INTX_FORMAT, _recursions);
   assert(_object != NULL, "must be non-NULL");
-  assert(_owner == NULL, "must be NULL: owner=" INTPTR_FORMAT, p2i(_owner));
 
-  Atomic::store(&_header, markWord::zero());
+  set_allocation_state(Free);
   _object = NULL;
 }
 
@@ -87,9 +125,9 @@
 
 // Clear _owner field; current value must match old_value.
 inline void ObjectMonitor::release_clear_owner(void* old_value) {
-  DEBUG_ONLY(void* prev = Atomic::load(&_owner);)
-  assert(prev == old_value, "unexpected prev owner=" INTPTR_FORMAT
-         ", expected=" INTPTR_FORMAT, p2i(prev), p2i(old_value));
+  void* prev = Atomic::load(&_owner);
+  ADIM_guarantee(prev == old_value, "unexpected prev owner=" INTPTR_FORMAT
+                 ", expected=" INTPTR_FORMAT, p2i(prev), p2i(old_value));
   Atomic::release_store(&_owner, (void*)NULL);
   log_trace(monitorinflation, owner)("release_clear_owner(): mid="
                                      INTPTR_FORMAT ", old_value=" INTPTR_FORMAT,
@@ -99,9 +137,9 @@
 // Simply set _owner field to new_value; current value must match old_value.
 // (Simple means no memory sync needed.)
 inline void ObjectMonitor::set_owner_from(void* old_value, void* new_value) {
-  DEBUG_ONLY(void* prev = Atomic::load(&_owner);)
-  assert(prev == old_value, "unexpected prev owner=" INTPTR_FORMAT
-         ", expected=" INTPTR_FORMAT, p2i(prev), p2i(old_value));
+  void* prev = Atomic::load(&_owner);
+  ADIM_guarantee(prev == old_value, "unexpected prev owner=" INTPTR_FORMAT
+                 ", expected=" INTPTR_FORMAT, p2i(prev), p2i(old_value));
   Atomic::store(&_owner, new_value);
   log_trace(monitorinflation, owner)("set_owner_from(): mid="
                                      INTPTR_FORMAT ", old_value=" INTPTR_FORMAT
@@ -109,11 +147,28 @@
                                      p2i(old_value), p2i(new_value));
 }
 
+// Simply set _owner field to new_value; current value must match old_value1 or old_value2.
+// (Simple means no memory sync needed.)
+inline void ObjectMonitor::set_owner_from(void* old_value1, void* old_value2, void* new_value) {
+  void* prev = Atomic::load(&_owner);
+  ADIM_guarantee(prev == old_value1 || prev == old_value2,
+                 "unexpected prev owner=" INTPTR_FORMAT ", expected1="
+                 INTPTR_FORMAT " or expected2=" INTPTR_FORMAT, p2i(prev),
+                 p2i(old_value1), p2i(old_value2));
+  _owner = new_value;
+  log_trace(monitorinflation, owner)("set_owner_from(old1=" INTPTR_FORMAT
+                                     ", old2=" INTPTR_FORMAT "): mid="
+                                     INTPTR_FORMAT ", prev=" INTPTR_FORMAT
+                                     ", new=" INTPTR_FORMAT, p2i(old_value1),
+                                     p2i(old_value2), p2i(this), p2i(prev),
+                                     p2i(new_value));
+}
+
 // Simply set _owner field to self; current value must match basic_lock_p.
 inline void ObjectMonitor::set_owner_from_BasicLock(void* basic_lock_p, Thread* self) {
-  DEBUG_ONLY(void* prev = Atomic::load(&_owner);)
-  assert(prev == basic_lock_p, "unexpected prev owner=" INTPTR_FORMAT
-         ", expected=" INTPTR_FORMAT, p2i(prev), p2i(basic_lock_p));
+  void* prev = Atomic::load(&_owner);
+  ADIM_guarantee(prev == basic_lock_p, "unexpected prev owner=" INTPTR_FORMAT
+                 ", expected=" INTPTR_FORMAT, p2i(prev), p2i(basic_lock_p));
   // Non-null owner field to non-null owner field is safe without
   // cmpxchg() as long as all readers can tolerate either flavor.
   Atomic::store(&_owner, self);
@@ -137,6 +192,46 @@
   return prev;
 }
 
+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_old() const {
+  return _allocation_state == Old;
+}
+
+inline bool ObjectMonitor::is_new() const {
+  return _allocation_state == New;
+}
+
+inline void ObjectMonitor::dec_ref_count() {
+  Atomic::dec(&_ref_count);
+  // Can be negative as part of async deflation protocol.
+  jint l_ref_count = ref_count();
+  ADIM_guarantee(AsyncDeflateIdleMonitors || l_ref_count >= 0,
+                 "sanity check: l_ref_count=%d, ref_count=%d", l_ref_count, ref_count());
+}
+
+inline void ObjectMonitor::inc_ref_count() {
+  Atomic::inc(&_ref_count);
+  // Can be negative as part of async deflation protocol.
+  jint l_ref_count = ref_count();
+  ADIM_guarantee(AsyncDeflateIdleMonitors || l_ref_count > 0,
+                 "sanity check: l_ref_count=%d, ref_count=%d", l_ref_count, ref_count());
+}
+
+inline jint ObjectMonitor::ref_count() const {
+  return Atomic::load(&_ref_count);
+}
+
 // The _next_om field can be concurrently read and modified so we
 // use Atomic operations to disable compiler optimizations that
 // might try to elide loading and/or storing this field.