hotspot/src/share/vm/gc_implementation/g1/g1RemSet.inline.hpp
author johnc
Mon, 02 Aug 2010 12:51:43 -0700
changeset 6247 00e5cc407d03
parent 5547 f4b087cbb361
child 6250 5680f968c721
permissions -rw-r--r--
6814437: G1: remove the _new_refs array Summary: The per-worker _new_refs array is used to hold references that point into the collection set. It is populated during RSet updating and subsequently processed. In the event of an evacuation failure it processed again to recreate the RSets of regions in the collection set. Remove the per-worker _new_refs array by processing the references directly. Use a DirtyCardQueue to hold the cards containing the references so that the RSets of regions in the collection set can be recreated when handling an evacuation failure. Reviewed-by: iveresov, jmasa, tonyp

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inline size_t G1RemSet::n_workers() {
  if (_g1->workers() != NULL) {
    return _g1->workers()->total_workers();
  } else {
    return 1;
  }
}

template <class T> inline void HRInto_G1RemSet::write_ref_nv(HeapRegion* from, T* p) {
  par_write_ref_nv(from, p, 0);
}

inline bool HRInto_G1RemSet::self_forwarded(oop obj) {
  bool result =  (obj->is_forwarded() && (obj->forwardee()== obj));
  return result;
}

template <class T> inline void HRInto_G1RemSet::par_write_ref_nv(HeapRegion* from, T* p, int tid) {
  oop obj = oopDesc::load_decode_heap_oop(p);
#ifdef ASSERT
  // can't do because of races
  // assert(obj == NULL || obj->is_oop(), "expected an oop");

  // Do the safe subset of is_oop
  if (obj != NULL) {
#ifdef CHECK_UNHANDLED_OOPS
    oopDesc* o = obj.obj();
#else
    oopDesc* o = obj;
#endif // CHECK_UNHANDLED_OOPS
    assert((intptr_t)o % MinObjAlignmentInBytes == 0, "not oop aligned");
    assert(Universe::heap()->is_in_reserved(obj), "must be in heap");
  }
#endif // ASSERT

  assert(from == NULL || from->is_in_reserved(p), "p is not in from");

  HeapRegion* to = _g1->heap_region_containing(obj);
  // The test below could be optimized by applying a bit op to to and from.
  if (to != NULL && from != NULL && from != to) {
    // The _par_traversal_in_progress flag is true during the collection pause,
    // false during the evacuation failure handing. This should avoid a
    // potential loop if we were to add the card containing 'p' to the DCQS
    // that's used to regenerate the remembered sets for the collection set,
    // in the event of an evacuation failure, here. The UpdateRSImmediate
    // closure will eventally call this routine.
    if (_par_traversal_in_progress &&
        to->in_collection_set() && !self_forwarded(obj)) {

      assert(_cset_rs_update_cl[tid] != NULL, "should have been set already");
      _cset_rs_update_cl[tid]->do_oop(p);

      // Deferred updates to the CSet are either discarded (in the normal case),
      // or processed (if an evacuation failure occurs) at the end
      // of the collection.
      // See HRInto_G1RemSet::cleanup_after_oops_into_collection_set_do().
    } else {
#if G1_REM_SET_LOGGING
      gclog_or_tty->print_cr("Adding " PTR_FORMAT " (" PTR_FORMAT ") to RS"
                             " for region [" PTR_FORMAT ", " PTR_FORMAT ")",
                             p, obj,
                             to->bottom(), to->end());
#endif
      assert(to->rem_set() != NULL, "Need per-region 'into' remsets.");
      to->rem_set()->add_reference(p, tid);
    }
  }
}

template <class T> inline void UpdateRSOopClosure::do_oop_work(T* p) {
  assert(_from != NULL, "from region must be non-NULL");
  _rs->par_write_ref(_from, p, _worker_i);
}

template <class T> inline void UpdateRSetImmediate::do_oop_work(T* p) {
  assert(_from->is_in_reserved(p), "paranoia");
  T heap_oop = oopDesc::load_heap_oop(p);
  if (!oopDesc::is_null(heap_oop) && !_from->is_survivor()) {
    _g1_rem_set->par_write_ref(_from, p, 0);
  }
}