HUB

Modern applications running on cloud data centers often consume a large amount of memory and their memory demands can vary during execution. Dynamic memory allocation is a necessity for high memory utilization. For a large dataset application, using hugepages instead of regular 4KB pages can efficiently reduce memory access and memory management overhead and improve overall performance. Virtualization, which is widely applied in data centers for server consolidation, brings new challenges to manage memory dynamically and effectively, especially for hugepages. In a virtualized system, ballooning is a popular mechanism used to dynamically adjust memory allocations for co-located virtual machines. We observe that the current Linux Kernel-Based Virtual Machine (KVM) does not support huge page ballooning. An application that can benefit from hugepages often loses its performance advantage when the guest OS experiences memory ballooning. This paper presents design and implementation of HUB, a HUgepage Ballooning mechanism in KVM which can dispatch memory in the granularity of hugepages. The experimental results show that our approach significantly reduces TLB misses and improves the overall performance for those applications with large memory demand.