@Override
  public int getSizeInBytes() {
    // Calling getSize includes the off heap header size.
    // We do not add anything to this since the size of the reference belongs to the region entry
    // size
    // not the size of this object.
    return getSize();
  }
We want this to include memory overhead so use getSize() instead of getDataSize().
geode-core/src/main/java/org/apache/geode/internal/offheap/OffHeapStoredObject.java