Towards Write-Activity-Aware Page Table Management for Non-volatile Main Memories

Non-volatile memories such as phase change memory (PCM) and memristor are being actively studied as an alternative to DRAM-based main memory in embedded systems because of their properties, which include low power consumption and high density. Though PCM is one of the most promising candidates with commercial products available, its adoption has been greatly compromised by limited write endurance. As main memory is one of the most heavily accessed components, it is critical to prolong the lifetime of PCM. In this article, we present write-activity-aware page table management (WAPTM), a simple yet effective page table management scheme for reducing unnecessary writes, by redesigning system software and exploiting write-activity-aware features provided by the hardware. We implemented WAPTM in Google Android based on the ARM architecture and evaluated it with real Android applications. Experimental results show that WAPTM can significantly reduce writes in page tables, proving the feasibility and potential of prolonging the lifetime of PCM-based main memory through reducing writes at the OS level.