src/share/vm/gc/shenandoah/shenandoahPartialGC.cpp

rev 13080 : Partial GC: Only evacuating threads push oop to work queue.

*** 277,301 ****
    if (! oopDesc::is_null(o)) {
      oop obj = oopDesc::decode_heap_oop_not_null(o);
      if (_heap->in_collection_set(obj)) {
        oop forw = ShenandoahBarrierSet::resolve_oop_static_not_null(obj);
        if (oopDesc::unsafe_equals(obj, forw)) {
!         forw = _heap->evacuate_object(obj, thread);
!       }
!       assert(! oopDesc::unsafe_equals(obj, forw) || _heap->cancelled_concgc(), "must be evacuated");
!       // TODO: Only the thread that succeeds *evacuating* the object should need to
!       // update the matrix and push the evacuated object to its queue. This would also
!       // enable to only have one CAS (the one in evacuate_object()) and use simple
!       // store for updating the ref.
!       oop oldval = _heap->atomic_compare_exchange_oop(forw, p, obj);
!       if (oopDesc::unsafe_equals(obj, oldval)) {
          assert(forw->is_oop(), "sanity");
          bool succeeded = queue->push(SCMTask(forw));
          assert(succeeded, "must succeed to push to task queue");
-       } else {
-         assert(oopDesc::unsafe_equals(oldval, forw), "other thread must have punched the same forwarded oop");
        }
        obj = forw; // For matrix update below.
      }
      // TODO: Make this templated
      if (update_matrix) {
  #ifdef ASSERT
--- 277,299 ----
    if (! oopDesc::is_null(o)) {
      oop obj = oopDesc::decode_heap_oop_not_null(o);
      if (_heap->in_collection_set(obj)) {
        oop forw = ShenandoahBarrierSet::resolve_oop_static_not_null(obj);
        if (oopDesc::unsafe_equals(obj, forw)) {
!         bool evacuated = false;
!         forw = _heap->evacuate_object(obj, thread, evacuated);
! 
!         // Only the thread that succeeded evacuating this object pushes it to its work queue.
!         if (evacuated) {
            assert(forw->is_oop(), "sanity");
            bool succeeded = queue->push(SCMTask(forw));
            assert(succeeded, "must succeed to push to task queue");
          }
+       }
+       assert(! oopDesc::unsafe_equals(obj, forw) || _heap->cancelled_concgc(), "must be evacuated");
+       // Update reference.
+       oopDesc::encode_store_heap_oop_not_null(p, forw);
        obj = forw; // For matrix update below.
      }
      // TODO: Make this templated
      if (update_matrix) {
  #ifdef ASSERT