Efficient management of reference blocks used in data deduplication

A data storage system, comprising:

• a non-volatile cache memory device including a buffer memory storing a plurality of comparison blocks;
• and
• a storage controller coupled to the non-volatile cache memory device, the storage controller including a processor configured to:
• initialize a data deduplication process utilizing the plurality of comparison blocks stored in the non-volatile cache memory device, and
• perform garbage collection in conjunction with the data deduplication process, wherein to perform the garbage collection, the processor is further configured to:
• maintain a hit count for comparison blocks of a passive set of comparison blocks in the buffer memory by incrementing or decrementing the hit count based on utilization of a comparison block in the data deduplication process, wherein the hit count is indicative of whether data in the comparison block matches data in an incoming user data block, and
• delete the passive set from the buffer memory responsive to the hit count satisfying a predetermined value.