A two-level main memory that includes a persistent memory and a cache is provided. Locations of dirty cache lines in the cache are tracked through the use a dirty cache line tracker. The dirty cache line tracker is stored in the cache and can be cached in a memory controller for the persistent memory. The dirty cache line tracker can be used to bypass cache lookup, perform efficient dirty cache line scrubbing and to decouple battery power and capacity of the cache in the two-level main memory.