Ingens: Huge Page Support for the OS and Hypervisor

摘要

Memory capacity and demand have grown hand in hand in recent years. However, overheads for memory virtu-alization, in particular for address translation, grow with memory capacity as well' motivating hardware manufacturers to provide TLBs with thousands of entries for larger pages, or huge pages. Current OSes and hypervi-sors support huge pages with a hodge-podge of best-effort algorithms and spot fixes that make less and less sense as architectural support for huge pages matures. The time has come for a more fundamental redesign. Ingens is a framework for providing transparent huge page support in a coordinated way. Ingens manages contiguity as a first-class resource, and tracks utilization and access frequency of memory pages, enabling it to eliminate pathologies that plague current systems. Experiments with a Linux/KVM-based prototype show improved fairness and performance, and reduced tail latency and memory bloat for important applications such as Web services and Redis. We report early experiences with our in-progress port of Ingens to the ESX Hypervisor.