src/hotspot/share/runtime/objectMonitor.cpp

rev 56046 : v2.00 -> v2.05 (CR5/v2.05/8-for-jdk13) patches combined into one; merge with 8229212.patch; merge with jdk-14+11; merge with 8230184.patch.
rev 56048 : Add OM_CACHE_LINE_SIZE so that ObjectMonitor cache line sizes can be experimented with independently of DEFAULT_CACHE_LINE_SIZE; for SPARC and X64 configs that use 128 for DEFAULT_CACHE_LINE_SIZE, we are experimenting with 64; move _previous_owner_tid and _allocation_state fields to share the cache line with ObjectMonitor::_header; put ObjectMonitor::_ref_count on its own cache line after _owner; add 'int* count_p' parameter to deflate_monitor_list() and deflate_monitor_list_using_JT() and push counter updates down to where the ObjectMonitors are actually removed from the in-use lists; monitors_iterate() async deflation check should use negative ref_count; add 'JavaThread* target' param to deflate_per_thread_idle_monitors_using_JT() add deflate_common_idle_monitors_using_JT() to make it clear which JavaThread* is the target of the work and which is the calling JavaThread* (self); g_free_list, g_om_in_use_list and g_om_in_use_count are now static to synchronizer.cpp (reduce scope); add more diagnostic info to some assert()'s; minor code cleanups and code motion; save_om_ptr() should detect a race with a deflating thread that is bailing out and cause a retry when the ref_count field is not positive; merge with jdk-14+11; add special GC support for TestHumongousClassLoader.java; merge with 8230184.patch.

*** 2109,2118 ****
--- 2109,2125 ----
        // once if the deflater thread happens to be slow.
        om_ptr->install_displaced_markword_in_object(object);
        om_ptr->dec_ref_count();
        return false;
      }
+     if (om_ptr->ref_count() <= 0) {
+       // Async deflation is in the process of bailing out, but has not
+       // yet restored the ref_count field so we return false to force
+       // a retry. We want a positive ref_count value for a true return.
+       om_ptr->dec_ref_count();
+       return false;
+     }
      // The ObjectMonitor could have been deflated and reused for
      // another object before we bumped the ref_count so make sure
      // our object still refers to this ObjectMonitor.
      const markWord tmp = object->mark();
      if (!tmp.has_monitor() || tmp.monitor() != om_ptr) {