private Fragment isAddrInFragmentFreeSpace(long addr) {
    for (Fragment f : fragmentList) {
      if (addr >= (f.getAddress() + f.getFreeIndex()) && addr < (f.getAddress() + f.getSize())) {
        return f;
      }
    }
    return null;
  }
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