@Override
  public RegionEntry putEntryIfAbsent(Object key, RegionEntry regionEntry) {
    RegionEntry oldRe = (RegionEntry) getEntryMap().putIfAbsent(key, regionEntry);
    if (oldRe == null && (regionEntry instanceof OffHeapRegionEntry) && _isOwnerALocalRegion()
        && _getOwner().isThisRegionBeingClosedOrDestroyed()) {
      // prevent orphan during concurrent destroy (#48068)
      Object v = regionEntry.getValue();
      if (v != Token.REMOVED_PHASE1 && v != Token.REMOVED_PHASE2 && v instanceof StoredObject
          && ((StoredObject) v).hasRefCount()) {
        if (getEntryMap().remove(key, regionEntry)) {
          ((OffHeapRegionEntry) regionEntry).release();
        }
      }
    }
    return oldRe;
  }
Tells this map what region owns it.
geode-core/src/main/java/org/apache/geode/internal/cache/AbstractRegionMap.java