src/hotspot/share/runtime/objectMonitor.inline.hpp

rev 54612 : Checkpoint latest preliminary review patches for full OpenJDK review; merge with 8222295.patch.
rev 54613 : imported patch dcubed.monitor_deflate_conc.v2.01
rev 54614 : imported patch dcubed.monitor_deflate_conc.v2.02
rev 54615 : imported patch dcubed.monitor_deflate_conc.v2.03

@@ -55,12 +55,12 @@
   return owner != DEFLATER_MARKER ? owner : NULL;
 }
 
 inline void ObjectMonitor::clear() {
   assert(_header != NULL, "must be non-NULL");
-  assert(_contentions == 0, "must be 0: contentions=%d", _contentions);
   assert(_owner == NULL, "must be NULL: owner=" INTPTR_FORMAT, p2i(_owner));
+  assert(_ref_count == 0, "must be 0: ref_count=%d", _ref_count);
 
   _header = NULL;
 
   clear_using_JT();
 }

@@ -69,34 +69,29 @@
   // 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, _contentions and _owner
+    // 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 _contentions < 0 will force any racing threads to retry. The
-    // _header field is used by install_displaced_markword_in_object()
+    // 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 values here.
+    // its value here.
     guarantee(_owner == NULL || _owner == DEFLATER_MARKER,
               "must be NULL or DEFLATER_MARKER: owner=" INTPTR_FORMAT,
               p2i(_owner));
-    guarantee(_contentions <= 0, "must be <= 0: contentions=%d", _contentions);
+    guarantee(_ref_count <= 0, "must be <= 0: ref_count=%d", _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=" INTPTR_FORMAT, _recursions);
   assert(_object != NULL, "must be non-NULL");
-  // 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);
   _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;
 }