LeakSurvivor: Towards Safely Tolerating Memory Leaks for Garbage-Collected Languages

Continuous memory leaks severely hurt program performance and software availability for garbage-collected programs. This paper presents a safe method, called LeakSurvivor, to tolerate continuous memory leaks at runtime for garbage-collected programs. Our main idea is to periodically swap out the “Potentially Leaked” (PL) memory objects identified by leak detectors from the virtual memory to disks. As a result, the virtual memory space occupied by the PL objects can be reclaimed by garbage collectors and available for future uses. If a swapped-out PL object is accesses later, LeakSurvivor will restore it from disks to the memory for correct program execution. Furthermore, LeakSurvivor helps developers to prune false positives. We have built the prototype of LeakSurvivor on top of Jikes RVM 2.4.2, a high performance Java-in-Java virtual machine developed by IBM. We conduct the experiments with three Java applications including Eclipse, SPECjbb2000 and Jigsaw. Among them, Eclipse and Jigsaw contain memory leaks introduced by their developers, while SPECjbb2000 contain a memory leak injected by us. Our results show that LeakSurvivor effectively tolerates memory leaks for two applications (Eclipse and SPECjbb2000), i.e., no cumulative performance degradation and no software failures when facing continuous memory leaks at runtime. For Jigsaw, LeakSurvivor extends the program lifetime by two times and improves the performance by 46% compared with native runs. Furthermore, when there are no memory leaks, LeakSurvivor imposes small runtime overhead, i.e., 2.5% over the leak detector and 23.7% over the native runs.