Cooperating Virtual Memory and Write Buffer Management for Flash-Based Storage Systems

Flash memory is becoming the preferred choice of secondary storage in mobile devices and embedded systems. The performance of Flash memory is dictated by asymmetric speeds of read and write, limited number of erase times, and the absence of in-place updates. To improve the performance of Flash-based storage systems, the write buffer has been provided in Flash memories recently. At the same time, new virtual memory management strategies have been proposed in recent studies that consider the characteristics of Flash memory. Currently, approaches on these two memory layers are considered separately, which fail to explore the full potential of these two layers. In this paper, we propose cooperative management schemes for virtual memory and write buffer to maximize the performance of Flash-memory-based systems. Management on virtual memory is designed to exploit write buffer status via reordering of the write sequences. The proposed write buffer management scheme works seamlessly with the proposed virtual memory management scheme. Experimental results show that significant improvement in I/O performance and reduction of the number of erase and write operations can be achieved compared to the state-of-art approaches.