关键词: 虚拟机, 内存资源管理, 独占缓存, Xen

Abstract: It is hard to accurately predict the memory demand of a virtual machine. Moreover, it is not reliable to request other virtual machines to release memory. Under-provision of memory will lead to severe performance degradation. To mitigate the impact, a hypervisor exclusive cache (HECache) is developed to extend the available memory of a virtual machine. A certain amount of memory is preserved as HECache in advance. The failed memory access in the VM is forwarded to HECache. All virtual machines running on the physical machine share HECache and can use it immediately. Through donating a little memory, all virtual machines can use more memory. The experiments conducted with both micro-benchmarks and real applications show that HECache can achieve up to 7. 9 times better performance, and the overhead is not significant compared with allocating the same amount of memory directly to a virtual machine. In addition, HECache is transparent to applications, and is complementary to the existing techniques such as ballooning, page-sharing, hotplug, etc.

Key words: virtual machine, memory resource management, exclusive cache, Xen