DMM: A dynamic memory mapping model for virtual machines

Memory virtualization is an important part in the design of virtual machine monitors (VMM). In this paper, we proposed dynamic memory mapping (DMM)model, a mechanism that allows the VMM to change the mapping between a virtual machine’s physical memory and the underlying hardware resource while the virtual machine is running. By utilizing DMM, the VMM can implement many novel memory management policies, such as Demand Paging, Swapping, Ballooning, Memory Sharing and Copy-On-Write, while preserving compatibility with various architectures. The modular and hierarchical property of the DMM model efficiently incorporates the high-level policies and the low-level implementations, leading to a feature-adjustable VMM design. We presented the principle of the DMM model, and explained the procedures of various memory management policies under this model. Also, we implement the DMM model in KVM, an open source VMM. Our evaluation shows that the DMM model is efficient enough to provide the benefits of dynamic memory resource management with little performance impact.