Hechi: A Hybrid Approach for Efficient Memory Reclamation Techniques in Mobile Systems

Application startup time, the time it takes for an application to become visible to the user from startup, is a crucial factor affecting user experience in mobile systems. The startup time of applications switching from the background (switching time) depends largely on the number of pages read from storage. When an application starts for the first time or reloads after being killed, it suffers from longer startup time (cold-launch time) as it begins from scratch. To mitigate this, minimizing application kills while retaining essential data in main memory can help, but it involves a tradeoff: reclaiming more file-backed pages (<monospace xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">file</monospace> pages) slows down switching due to the overhead of fetching them from storage, while reclaiming more anonymous pages (<monospace xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">anon</monospace> pages) that not associated with any file risks app termination due to limited swap space. Hechi addresses this tradeoff using a hybrid memory reclamation approach. By deprioritizing the reclamation of essential file pages and dynamically adjusting the reclamation ratio of the two types of pages based on the system states, Hechi improves startup time by up to 17%.