End the Senseless Killing: Improving Memory Management for Mobile Operating Systems

To ensure low-latency memory allocation, mobile operating systems kill applications instead of swapping memory to disk. This design choice shifts the burden of managing over-utilized memory to application programmers, requiring them to constantly checkpoint their application state to disk. This paper presents Marvin, a new memory manager for mobile platforms that efficiently supports swapping while meeting the strict performance requirements of mobile apps. Marvin's swap-enabled language runtime is co-designed with OS-level memory management to avoid common pitfalls of traditional swap mechanisms. Its key features are: (1) a new swap mechanism, called ahead-of-time (AOT) swap, which pre-writes memory to disk, then harvests it quickly when needed, (2) a modified bookmarking garbage collector that avoids swapping in unused memory, and (3) an object-granularity working set estimator. Our experiments show that Marvin can run more than 2x as many concurrent apps as Android, and that Marvin can reclaim memory over 60x faster than Android with a Linux swap file can allocate memory under memory pressure.