Saving and Restoring State Information for Virtualized Computer Systems
First Claim
1. A method for restoring state information in a virtual machine (“
- VM”
) and resuming operation of the VM, the state information having been saved in connection with earlier operation of the VM, the state information for the VM comprising virtual disk state information, device state information and VM memory state information, the method comprising;
restoring access to a virtual disk for the VM;
restoring device state for the VM;
loading into physical memory one or more memory pages from a previously identified set of active memory pages for the VM, the set of active memory pages having been identified as being recently accessed prior to or during the saving of the state information of the VM, the set of active memory pages comprising a proper subset of the VM memory pages;
after the one or more memory pages from the previously identified set of active memory pages have been loaded into physical memory, resuming operation of the VM; and
after resuming operation of the VM, loading into physical memory additional VM memory pages.
1 Assignment
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Accused Products
Abstract
Prior to or while the state of a virtual machine (“VM”) is being saved, such as in connection with the suspension or checkpointing of a VM, a set of one or more “active” memory pages is identified, this set of active memory pages comprising memory pages that are in use within the VM before operation of the VM is suspended. This set of active memory pages may constitute a “working set” of memory pages. To restore the state of the VM and resume operation, in some embodiments, (a) access to persistent storage is restored to the VM, device state for the VM is restored, and one or more of the set of active memory pages are loaded into physical memory; (b) operation of the VM is resumed; and (c) additional memory pages from the saved state of the VM are loaded into memory after operation of the VM has resumed.
164 Citations
28 Claims
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1. A method for restoring state information in a virtual machine (“
- VM”
) and resuming operation of the VM, the state information having been saved in connection with earlier operation of the VM, the state information for the VM comprising virtual disk state information, device state information and VM memory state information, the method comprising;restoring access to a virtual disk for the VM; restoring device state for the VM; loading into physical memory one or more memory pages from a previously identified set of active memory pages for the VM, the set of active memory pages having been identified as being recently accessed prior to or during the saving of the state information of the VM, the set of active memory pages comprising a proper subset of the VM memory pages; after the one or more memory pages from the previously identified set of active memory pages have been loaded into physical memory, resuming operation of the VM; and after resuming operation of the VM, loading into physical memory additional VM memory pages. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
- VM”
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15. A computer program product embodied in a computer-readable medium, the computer program product performing a method for restoring state information in a virtual machine (“
- VM”
) and resuming operation of the VM, the state information having been saved in connection with earlier operation of the VM, the state information for the VM comprising virtual disk state information, device state information and VM memory state information, the method comprising;restoring access to a virtual disk for the VM; restoring device state for the VM; loading into physical memory one or more memory pages from a previously identified set of active memory pages for the VM, the set of active memory pages having been identified as being recently accessed prior to or during the saving of the state information of the VM, the set of active memory pages comprising a proper subset of the VM memory pages; after the one or more memory pages from the previously identified set of active memory pages have been loaded into physical memory, resuming operation of the VM; and after resuming operation of the VM, loading into physical memory additional VM memory pages. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
- VM”
Specification