Transparent Smartphone Memory Expansion

Traditionally, mobile systems avoid virtual memory swapping to flash memory due to wear-out and latency issues. Instead, mobile systems kill background applications to secure free memory but this leads to long-latency cold startup of applications, thereby resulting in degraded user experience. With the advance of mobile network technologies, network-based memory expansion can offer a solution, allowing users to leverage large back-end memory on edge servers. However, traditional memory expansion methods still suffer from high latency due to on-demand page faults and difficulty in identifying numerous cold pages. We propose a novel memory expansion scheme tailored for fast networks in mobile systems. Our scheme minimizes the on-demand network latency of remote I/O by bulk-prefetching pages based on access sequences during application launches. Our system also effectively identifies and exports cold pages to the edge, freeing up local memory. Our evaluations show a 41% reduction in displayed time and 62% memory expansion with 42% faster launch times, outperforming both traditional swapping and app-killing mechanisms of conventional systems.