VirtualSpaceSummary ParallelScavengeHeap::create_perm_gen_space_summary() {
  PSVirtualSpace* space = perm_gen()->virtual_space();
  return VirtualSpaceSummary(
    (HeapWord*)space->low_boundary(),
    (HeapWord*)space->high(),
    (HeapWord*)space->high_boundary());
}
VirtualSpaceSummary CollectedHeap::create_heap_space_summary() {
  size_t capacity_in_words = capacity() / HeapWordSize;

  return VirtualSpaceSummary(
    reserved_region().start(), reserved_region().start() + capacity_in_words, reserved_region().end());
}