Described embodiments provide arbitration for a cache of a network processor. Processing modules of the network processor generate memory access requests including a requested address and an ID value corresponding to the requesting processing module. Each request is either a locked request or a simple request. An arbiter determines whether the received requests are locked requests. For each locked request, the arbiter determines whether two or more of the requests are conflicted based on the requested address of each received memory requests. If one or more of the requests are non-conflicted, the arbiter determines, for each non-conflicted request, whether the requested addresses are locked out by prior memory requests based on a lock table. If one or more of the non-conflicted memory requests are locked-out by prior memory requests, the arbiter queues the locked-out memory requests. The arbiter grants any non-conflicted memory access requests that are not locked-out.