Flash-aware linux swap system for portable consumer electronics

Because of limited memory resource of portable consumer electronics, portable consumer electronics currently exploit swap space with flash memory as a cost effective solution to extend limited memory space. Original swap space management scheme used in Linux for magnetic disk is not available to flash memory-based swap space due to the distinct characteristics of flash memory. In this paper, we propose a flash-aware Linux swap system, called FLSS, which adopts Linux kernel 2.6 to manage flash memory-based swap space directly without FTL. We introduce: 1) a partial block alignment scheme to perform an efficient swap-in read-ahead algorithm, 2) a swap-aware victim block selection method and the redefined concept of hot page and cold page to design a swap-aware garbage collection policy called SACATA, and 3) the notion of overage as well as the notion of frozen applied to blocks to exploit a wear leveling-aware block management scheme. Experimental results show that the proposed FLSS greatly outperforms existing swap space management techniques and evaluate the effectiveness of proposed SACATA.