@Override
  public void removeEntry(Object key, RegionEntry regionEntry, boolean updateStat) {
    if (regionEntry.isTombstone() && getEntryMap().get(key) == regionEntry) {
      logger.fatal(
          "Internal product error: attempt to directly remove a versioned tombstone from region entry map",
          new Exception("stack trace"));
      return; // can't remove tombstones except from the tombstone sweeper
    }
    if (getEntryMap().remove(key, regionEntry)) {
      regionEntry.removePhase2();
      if (updateStat) {
        incEntryCount(-1);
      }
    }
  }
Tells this map what region owns it.
geode-core/src/main/java/org/apache/geode/internal/cache/AbstractRegionMap.java