1. A method of facilitating processing of a multiprocessor computer system, the method comprising: deciding by a processor, pursuant to processing of a request to update a previous storage key to a new storage key, whether to purge the previous storage key from, or update the previous storage key in, local processor cache of the multiprocessor computer system, the deciding comprising: comparing a bit value(s) of at least one required component of the previous storage key to a predefined allowed stale value(s) for the at least one required component; and leaving the previous storage key in local processor cache of the multiprocessor computer system if the bit value(s) of the at least one required component in the previous storage key equals the predefined allowed stale value(s) for the at least one required component, wherein the leaving minimizes interprocessor communication pursuant to processing of the request to update the previous storage key to the new storage key.