1. A method for multi-level exclusive caching, the method comprising: defining a cache management protocol within a multi-level cache hierarchy having a plurality of caches, including deciding caches and non-deciding caches; defining a hint protocol within the multi-level cache hierarchy; and implementing the hint protocol in conjunction with the cache management protocol to decide which pages within the multi-level cache to retain and where to store the pages, wherein the hint protocol includes an ‘I keep’ hint and an ‘U keep’ hint passed from the deciding caches to the non-deciding caches to determine, respectively, if the pages are retained in and sent from the deciding cache.