private void getRegionLiveChunks(Region<?, ?> r, List<OffHeapStoredObject> result) {
    if (r.getAttributes().getOffHeap()) {

      if (r instanceof PartitionedRegion) {
        PartitionedRegionDataStore prs = ((PartitionedRegion) r).getDataStore();
        if (prs != null) {
          Set<BucketRegion> brs = prs.getAllLocalBucketRegions();
          if (brs != null) {
            for (BucketRegion br : brs) {
              if (br != null && !br.isDestroyed()) {
                basicGetRegionLiveChunks(br, result);
              }

            }
          }
        }
      } else {
        basicGetRegionLiveChunks((InternalRegion) r, result);
      }

    }

  }
Returns a possibly empty list that contains all the Chunks used by regions.
geode-core/src/main/java/org/apache/geode/internal/offheap/MemoryAllocatorImpl.java