void HeapInspection::heap_inspection(outputStream* st, bool need_prologue) {
  ResourceMark rm;
  HeapWord* ref;

  CollectedHeap* heap = Universe::heap();
  bool is_shared_heap = false;
  switch (heap->kind()) {
    case CollectedHeap::G1CollectedHeap:
    case CollectedHeap::GenCollectedHeap: {
      is_shared_heap = true;
      SharedHeap* sh = (SharedHeap*)heap;
      if (need_prologue) {
        sh->gc_prologue(false /* !full */); // get any necessary locks, etc.
      }
      ref = sh->perm_gen()->used_region().start();
      break;
    }
#ifndef SERIALGC
    case CollectedHeap::ParallelScavengeHeap: {
      ParallelScavengeHeap* psh = (ParallelScavengeHeap*)heap;
      ref = psh->perm_gen()->object_space()->used_region().start();
      break;
    }
#endif // SERIALGC
    default:
      ShouldNotReachHere(); // Unexpected heap kind for this op
  }
  // Collect klass instance info
  KlassInfoTable cit(KlassInfoTable::cit_size, ref);
  if (!cit.allocation_failed()) {
    // Iterate over objects in the heap
    RecordInstanceClosure ric(&cit);
    // If this operation encounters a bad object when using CMS,
    // consider using safe_object_iterate() which avoids perm gen
    // objects that may contain bad references.
    Universe::heap()->object_iterate(&ric);

    // Report if certain classes are not counted because of
    // running out of C-heap for the histogram.
    size_t missed_count = ric.missed_count();
    if (missed_count != 0) {
      st->print_cr("WARNING: Ran out of C-heap; undercounted " SIZE_FORMAT
                   " total instances in data below",
                   missed_count);
    }
    // Sort and print klass instance info
    KlassInfoHisto histo("\n"
                     " num     #instances         #bytes  class name\n"
                     "----------------------------------------------",
                     KlassInfoHisto::histo_initial_size);
    HistoClosure hc(&histo);
    cit.iterate(&hc);
    histo.sort();
    histo.print_on(st);
  } else {
    st->print_cr("WARNING: Ran out of C-heap; histogram not generated");
  }
  st->flush();

  if (need_prologue && is_shared_heap) {
    SharedHeap* sh = (SharedHeap*)heap;
    sh->gc_epilogue(false /* !full */); // release all acquired locks, etc.
  }
}
void HeapInspection::epilogue() {
  if (is_shared_heap()) {
    SharedHeap* sh = SharedHeap::heap();
    sh->gc_epilogue(false /* !full */); // release all acquired locks, etc.
  }
}