基于块更新序号的NAND闪存垃圾回收算法

传统NAND闪存垃圾回收算法的管理粒度为块,后续逐渐发展为基于页管理,以更大的内存消耗为代价来提高对数据热度判断的准确度。针对现有算法中存在的不足,提出了一种基于块更新序号的NAND闪存垃圾回收算法。该算法将管理粒度重新定位到块上,定义块的更新序号,提出新的基于动态阈值分段处理的数据热度计算方法以进行更有效的冷热分离,同时回收块选择策略采用新的代价函数以兼顾回收效率与磨损均衡。实验结果表明,提出算法在减少系统内存消耗的同时,获得了比GR、CB、CAT、FaGC、LRGC和LRGC+算法更好的垃圾回收效率和磨损均衡效果。

Garbage collection algorithm for NAND flash memory based on block update sequence number

The management granularity of the traditional NAND flash memory garbage collection algorithm is block, and the subsequent development is based on page management, which improves the accuracy of calculating the heat of data at the cost of greater memory consumption. Taking into account the deficiencies of existing NAND flash garbage collection algorithms, a garbage collection algorithm based on block update sequence number is proposed. The proposed algorithm re-uses a block based management granularity, defines the update sequence number of the block, and presents a new method for calculating the heat of data based on dynamic threshold segmentation processing in order to perform effective cold and hot separation. At the same time, the victim block selection strategy adopts a new cost function to make a balance between efficiency and wear leveling. The experimental results show that while reducing system memory consumption, the proposed algorithm can achieve better garbage collection efficiency and wear leveling effect than GR, CB, CAT, FaGC, LRGC and LRGC+ algorithms.