Tracking guest memory characteristics for memory scheduling

摘要

A system and method are disclosed for improving operation of a memory scheduler operating on a host machine supporting virtual machines (VMs) in which guest operating systems and guest applications run. For each virtual machine, the host machine hypervisor categorizes memory pages into memory usage classes and estimates the total number of pages for each memory usage class. The memory scheduler uses this information to perform memory reclamation and allocation operations for each virtual machine. The memory scheduler further selects between ballooning reclamation and swapping reclamation operations based in part on the numbers of pages in each memory usage class for the virtual machine. Calls to the guest operating system provide the memory usage class information. Memory reclamation not only can improve the performance of existing VMs, but can also permit the addition of a VM on the host machine without substantially impacting the performance of the existing and new VMs.

主权项

1. A method of allocating memory pages of a computer system having a virtual machine (VM) running in the computer system, wherein a memory reclamation operation is executed in the computer system to reclaim a target number of memory pages of the VM, comprising:
characterizing memory pages of the VM into multiple memory usage classes; estimating the total number of memory pages in each of the multiple memory usage classes; determining that the VM has insufficient memory based on the estimated numbers; and decreasing the target number of memory pages based on the estimated numbers of memory pages in each of the multiple memory usage classes to cause allocation of additional memory pages to the VM.