1. A method comprising: a prefetch unit monitoring memory accesses and determining whether to prefetch one or more blocks of memory from a system memory based upon previous memory accesses; detecting memory access patterns using addresses of the previous memory accesses; calculating each next memory block to prefetch using addresses of the memory accesses; in response to detecting a memory access instruction including a particular hint, providing a notification; and in response to receiving the notification, the prefetch unit discarding an address associated with the memory access instruction including the particular hint so that calculations of subsequent memory blocks to prefetch do not include the discarded address.