Thoughts on Merging the File System with the Virtual Memory System: Design decisions and their ramifications in developing the Osprey kernel
Bruce Jacob · Proceedings of the International Symposium on Memory Systems · 2023
Near-future computer systems will see the integration of nonvolatile memories into main memory, offering superior density and energy efficiency compared to traditional DRAM. This will prompt a paradigm shift in operating system memory management, driven by the potential merger of the disk and main memory subsystems. This paper discusses possible design directions for a merged memory-management approach in the context of the Osprey kernel, a prototype for exploring the design space. By fusing the file-system and virtual-memory subsystems, Osprey achieves seamless memory mapping, encompassing both application workspace and file-system data, and simplifying kernel code substantially. The design facilitates protection, relocation, memory-mapped files, executable files, and shared memory, with the potential for further enhancements.