1. A method for memory management in a storage hierarchy comprising a tag cache in communication with one or more cache devices, the method comprising: prefetching, via tag contents of the tag cache, specified memory lines of a memory block into the cache device, the tag cache including tags of recently accessed memory blocks, each tag corresponding to one of the memory blocks and including the tag contents; wherein the prefetching includes using a next virtual memory block bit in the tag contents to control prefetching of memory lines from a next virtual memory block, comprising: setting the next virtual memory block bit in a preceding memory block in a virtual address space to a prefetch status when the preceding memory block tag is in the tag cache; and setting the next virtual memory block bit to a non-prefetch status with a specified probability on certain events.