Dynamic Memory Demand Estimating Based on the Guest Operating System Behaviors for Virtual Machines

In the virtualized environment, memory can be efficiently utilized if the dynamic memory demands of virtual machines can be estimated at runtime. An efficient memory estimator should report the appropriate size of the memory which can be made full use of by the virtual machine while keeping reasonable performance. However, the appropriate size is hard to be estimated accurately with low overhead. This paper presents a memory demand estimator based on the guest operating system behaviors architecturally visible to the virtual machine monitor, and it can accurately reports the expected appropriate memory size with negligible overhead. The estimator consists of two components which respectively, track the amount of the memory residing in virtual address space, and the memory used as page cache only accessible in kernel mode. The experimental results show that the estimation error is only 0.4%~2.1%, and the runtime overhead is only 0.8% on average due to no additional memory protection traps are introduced.