1. A method of facilitating processing of a multiprocessor computer system, the method comprising: setting, in association with invalidate page table entry processing, a storage key at a matching location in central storage of the multiprocessor computer system to a predefined value; and subsequently executing a request to update the storage key to a new storage key, the subsequently executing including determining whether the predefined value is an allowed stale value, and responsive to the predefined value being the allowed stale value, replacing in central storage the storage key of predefined value with the new storage key without requiring purging or updating of the storage key of predefined value in any local processor cache of the multiprocessor computer system, thereby minimizing interprocessor communication pursuant to processing of the request to update the storage key to the new storage key.