HMM-V: Heterogeneous Memory Management for Virtualization

TL;DR

HMM-V is a system that manages heterogeneous memory in virtualized environments, intelligently migrating pages between DRAM and NVM to improve VM performance and resource utilization.

Contribution

This paper introduces HMM-V, a novel memory management system tailored for virtualization that effectively balances DRAM and NVM to optimize performance.

Findings

HMM-V achieves up to 51% performance improvement over NUMA balancing.

HMM-V outperforms hardware management (Intel Optane mode) by 31%.

Efficient page migration reduces access pause and handles dirty pages effectively.

Abstract

The memory demand of virtual machines (VMs) is increasing, while DRAM has limited capacity and high power consumption. Non-volatile memory (NVM) is an alternative to DRAM, but it has high latency and low bandwidth. We observe that the VM with heterogeneous memory may incur up to a $1.5\times$ slowdown compared to a DRAM VM, if not managed well. However, none of the state-of-the-art heterogeneous memory management designs are customized for virtualization on a real system. In this paper, we propose HMM-V, a Heterogeneous Memory Management system for Virtualization. HMM-V automatically determines page hotness and migrates pages between DRAM and NVM to achieve performance close to the DRAM system. First, HMM-V tracks memory accesses through page table manipulation, but reduces the cost by leveraging Intel page-modification logging (PML) and a multi-level queue. Second, HMM-V quantifies the ``temperature'' of page and determines the hot set with bucket-sorting. HMM-V then efficiently migrates pages with minimal access pause and handles dirty pages with the assistance of PML. Finally, HMM-V provides pooling management to balance precious DRAM across multiple VMs to maximize utilization and overall performance. HMM-V is implemented on a real system with Intel Optane DC persistent memory. The four-VM co-running results show that HMM-V outperforms NUMA balancing and hardware management (Intel Optane memory mode) by $51\%$ and $31\%$, respectively.