一种基于闪存的缓冲区管理算法

A Buffer Management Algorithm Based on Flash Memory

在大多数以磁盘为存储系统的操作系统中,缓冲区管理算法只考虑到了数据访问的命中率。然而,闪存的写操作代价远远大于读操作代价。为了提高闪存性能,本文提出的O-CFLRU(Optimal CFLRU)算法对于CFLRU(Clean First LRU)算法做了优化。该算法用一种页-块混合的数据结构来分别管理缓冲区中的干净页面和脏的数据页面聚簇。当缓冲区空间不够时,优先置换干净页面,再置换出脏的数据页聚簇,从而减少了写回的次数和随机写带来的擦除次数,提高了闪存的性能。

In most operating systems which are disk-based system, buffer management algorithm concerns only data hit ratio. However, write cost of flash memory is much more than read cost. In order to improve the performance of flash, we propose the O-CFLRU algorithm which is an optimal of the CFLRU. This algorithm used a mixed page-block data structure to manage clean pages and dirty page clusters. When buffer had no spare space, clean page was preferred to be evicted and dirty pages cluster was evicted from list at last. In this way, performance is improved by reducing writing and erasing.