private DiskRegionInfo getOrCreateDRI(long drId) {
    DiskRegionInfo dri = getDRI(drId);
    if (dri == null) {
      dri = (isCompactionPossible() || couldHaveKrf())
          ? new DiskRegionInfoWithList(null, couldHaveKrf(), krfCreated.get())
          : new DiskRegionInfoNoList(null);
      DiskRegionInfo oldDri = regionMap.get().putIfAbsent(drId, dri);
      if (oldDri != null) {
        dri = oldDri;
      }
    }
    return dri;
  }
@return true if this Oplog could end up having a KRF file.
geode-core/src/main/java/org/apache/geode/internal/cache/Oplog.java