long getFreeHugeMemory() {
    long hugeFree = 0;
    for (OffHeapStoredObject c : hugeChunkSet) {
      hugeFree += c.getSize();
    }
    return hugeFree;
  }
If addr is in the free space of a fragment then return that fragment; otherwise return null.
geode-core/src/main/java/org/apache/geode/internal/offheap/FreeListManager.java