Cache Pre-Allocation of Ways for Pipelined Allocate Requests

This invention is a data processing system with a data cache. The cache controller responds to a cache miss requiring allocation by pre-allocating a way in the set to an allocation request according to said least recently used indication of said ways and then update the least recently used indication of remaining ways of the set. This permits read allocate requests to the same set to proceed without introducing processing stalls due to way contention. This also allows multiple outstanding allocate requests to the same set and way combination. The cache also compares the address of a newly received allocation request to stall this allocation request if the address matches an address of any pending allocation request.