The DEMOTE Technique

Figure 2: The DEMOTE technique. When a client is about to eject a clean block from its cache, it sends the clean block to the lower cache using the DEMOTE operation. The lower cache puts the demoted block into its cache, ejecting another block if necessary to make space. Hits in any list are sent to the MRU end of the appropriate highest cache.

The DEMOTE technique [33], or equivalently the Global technique [35], shown in Figure 2, can be applied to many general purpose single-level caching policies (like, LRU, MQ, ARC, etc) to create multi-level versions that achieve exclusivity of cache contents. As with any exclusive caching scheme, DEMOTE should only be used in scenarios that benefit from exclusive caching [33,27].