Fast Memory Deduplication of Disk Cache Pages in Virtual Environments

摘要

In virtualized cloud computing environments, the memory resource is becoming the major bottleneck for limiting server consolidation degree of virtual machines. The fact that great amount of redundant cache pages exist in the consolidated virtual machines' disk cache, which we refer to as multi-caching problem, give us a chance to improve the efficiency of memory resource utilization. Previous scanning-based memory deduplication is a well-known technique to eliminate redundant pages with identical content. But the periodically scanning cost is expensive, and it is hard to detect short-lived sharing opportunities. In this paper, we present a fast memory deduplication technique for disk cache pages named FMD. It tracks the disk I/O operations of guest virtual machines transparently and collapses identical cache copies into a single page as soon as they enter the memory. The experimental results on the prototype in the KVM hypervisor show that FMD can detect and remove duplicate disk cache copies with negligible overhead.