Virtual machine migration with swap pages

摘要

Migration of a virtual machine to a new host is coordinated while data that is mapped into virtual (swap) memory of a source instance of the virtual machine (or guest) is properly handled. Sharing rights for one or more swap devices can be modified to facilitate the use of the swap devices by a new host and a corresponding (target) instance of virtual machine running on the new host.

主权项

1. A system for migrating a virtual machine between hypervisors that each support memory over commitment, the system comprising:
one or more computer processor circuits and memory that are configured to provide:
a source hypervisor configured to:
receive a migration request that specifies a source instance of the virtual machine on the source hypervisor and a target hypervisor;identify at least one swap device that is used by the source instance of the virtual machine and that is physically accessible by the target hypervisor;identify, for each identified swap device, one or more source swap slots that store at least one swapped out page of over committed memory of the source instance of the virtual machine; andhalt processing by the source instance of the virtual machine;the target hypervisor configured to:
associate a target instance of the virtual machine with a swap table that references the one or more swap slots granted to the target hypervisor;use the one or more swap slots to populate swapped out virtual memory for the target instance of virtual machine; andcarry out a cleanup of swap slots by:
copying, by a background process of the target hypervisor, a particular swapped slot from a shared swap device that is shared with the source hypervisor to another swap device owned by the target hypervisor;removing access to the shared swap device for the target hypervisor;granting the particular swap slot to the source hypervisor;determining that all swap slots stored on a particular shared swap device are assigned to the target hypervisor; andrequesting that a resource manager remove the particular shared swap device from a sharing table that contains information identifying shared swap devices and assignment of swap slots in said shared swap devices to hypervisors; and a firmware module configured to grant, to the target hypervisor, access to the one or more source swap slots identified by the source hypervisor.