The mechanics of memory-related software aging

Software aging is a phenomenon defined as the continuing degradation of software systems during runtime, being particularly noticeable in long-running applications. Memory-related aging effects are one of the most important problems in this research field. Therefore understanding their causes and how they work is a major requirement in designing dependable software systems. In this paper we go deep into how memory management works inside application process, focusing on two memory problems that cause software aging: fragmenting and leakage. We explain the mechanics of memory-related software aging effects dissecting a real and widely adopted memory allocator. Along with the theoretical explanation, we present an experimental study that illustrates how memory fragmenting and leakage occur and how they accumulate over time in order to cause system aging-related failures.