Dynamic Memory Pressure Aware Ballooning

Hardware virtualization is a major component of large scale server and data center deployments due to their facilitation of server consolidation and scalability. Virtualization, however, comes at a high cost in terms of system main memory utilization. Current virtual machine (VM) memory management solutions impose a high performance penalty and are oblivious to the operating regime of the system. Therefore, there is a great need for low-impact VM memory management techniques which are aware of and reactive to current system state, to drive down the overheads of virtualization. We observe that the host machine operates under different memory pressure regimes, as the memory demand from guest VMs changes dynamically at runtime. Adapting to this runtime system state is critical to reduce the performance cost of VM memory management. In this paper, we propose a novel dynamic memory management policy called Memory Pressure Aware (MPA) ballooning. MPA ballooning dynamically allocates memory resources to each VM based on the current memory pressure regime. Moreover, MPA ballooning proactively reacts and adapts to sudden changes in memory demand from guest VMs. MPA ballooning requires neither additional hardware support, nor incurs extra minor page faults in its memory pressure estimation. We show that MPA ballooning provides an 13.2% geomean speed-up versus the current ballooning techniques across a set of application mixes running in guest VMs; often yielding performance nearly identical to that of a non-memory constrained system.