File-based Memory Management for Non-Volatile Main Memory

Active research and development efforts on byte addressable non-volatile (NV) memory technologies, such as STT-RAM, PCM, and ReRAM, have been conducted in recent years. Because they are byte addressable, they can be used as main memory by directly connecting them to CPUs. Because they are non-volatile, they can also be used as storage device. While there were the active researches on their use for either main memory or secondary storage, these researches were conducted independently. This paper presents the memory management methods that enable the integration of main memory and file systems; thus, both main memory and storage are realized on the same byte addressable NV memory. The presented methods construct a file system on NV memory, and memory blocks assigned to files are exported for the use of main memory. We implemented the proposed methods in the Linux kernel, and performed their evaluation. The evaluation results show that the file-based methods can perform comparably to the existing DRAM memory allocator and can maintain the consistency of a file system.