System, method and program to preserve a cache of a virtual machine

• US 20060136667A1
• Filed: 12/17/2004
• Published: 06/22/2006
• Est. Priority Date: 12/17/2004
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Tkatschow, Xenia, Shultz, Steven
• Granted Patent: US 8,060,683 B2
• Time in Patent Office: Days
• US Class Current: 711/118
• CPC Class Codes: G06F 12/0842 for multiprocessing or multitasking
• CPC Class Codes: G06F 12/0866 for peripheral storage systems, e.g. disk cache
• CPC Class Codes: G06F 9/5077 Logical partitioning of resources; Management or configuration of virtualized resources specific details on emulation or internal functioning of virtual machines G06F9/455

Abstract

A system, computer program product and method for managing a cache of a virtual machine. A cache is defined in memory, and a virtual machine is assigned to the cache. An identity of the cache is recorded in storage. The virtual machine terminates, and the cache and contents of the cache are preserved despite the termination of the virtual machine, such that if the virtual machine subsequently resumes operating, the virtual machine can access the cache and its contents. There is also a system, method and computer program product for managing a cache of an LPAR. A cache is defined in memory, and assigned to an LPAR. A record is made of an identity of the cache in storage. The LPAR terminates, and the cache and contents of the cache are preserved despite the termination of the LPAR, such that if the LPAR subsequently resumes operating, the LPAR can access the cache and its contents.

Claims

1. A method for managing a cache of a virtual machine, said method comprising the steps of:

defining a cache in memory, assigning said cache to a virtual machine, and recording an identity of said cache in storage; and

said virtual machine terminating, and preserving said cache and contents of said cache despite said termination of said virtual machine, such that if said virtual machine subsequently resumes operating, said virtual machine can access said cache and said contents.

2. A method as set forth in claim 1 further comprising the steps of:

defining a second virtual machine on a same real computer as the first said virtual machine;

recording that both said first and second virtual machines are users of said cache, such that when said first virtual machine terminates, there is still one operational user recorded for said cache, and the step of preserving said cache and its contents when said first virtual machine terminates is based on the record of the one operational user for said cache.

3. A method as set forth in claim 1 further comprising the steps of:

said virtual machine requesting an attachment to said cache, and in response, recording that said virtual machine is a user of said cache; and

a second virtual machine requesting an attachment to said cache, and in response, recording that said second virtual machine is another user of said cache.

4. A method as set forth in claim 1 further comprising the steps of:

said virtual machine making a request to a hypervisor of said virtual machine to attach to said cache and preserve said cache in case said virtual machine terminates, and in response, said hypervisor defining a table which correlates to said cache virtual addresses used by said virtual machine for said cache, said table surviving termination of said virtual machine, whereby said cache is preserved in case of termination of said virtual machine.

5. A method as set forth in claim 4 further comprising the steps of:

another virtual machine on a same real computer as the first said virtual machine making a request to said hypervisor to attach to another cache but not preserve said other cache in case said other virtual machine terminates, and in response, said hypervisor defining another table which correlates to said other cache virtual addresses used by said other virtual machine for said other cache, said other table being deleted upon termination of said other virtual machine, whereby said other cache is deleted in case of termination of said other virtual machine.

6. A method as set forth in claim 1 further comprising the steps of:

said virtual machine making a request to a hypervisor of said virtual machine to attach to said cache and preserve said cache in case said virtual machine terminates, and in response, said hypervisor making a record that said cache should be preserved in case of termination of said virtual machine, and when said virtual machine terminates, said hypervisor preserving said cache and contents of said cache, such that if said virtual machine resumes operation, said virtual machine can access said cache and said contents.

7. A method as set forth in claim 6 further comprising the subsequent steps of:

said virtual machine resuming operation; and

restoring to said virtual machine access to said cache and said contents.

8. A method as set forth in claim 1 further comprising the subsequent steps of:

said virtual machine resuming operation; and

restoring to said virtual machine access to said cache and said contents.

9. A system comprising:

means for defining a cache in memory, assigning said cache to a virtual machine, and recording an identity of said cache in storage; and

means for terminating said virtual machine, and preserving said cache and contents of said cache despite said termination of said virtual machine, such that if said virtual machine subsequently resumes operating, said virtual machine can access said cache and said contents.

10. A system as set forth in claim 9 further comprising:

means for defining a second virtual machine on a same real computer as the first said virtual machine;

means for recording that both said first and second virtual machines are users of said cache, such that when said first virtual machine terminates, there is still one operational user recorded for said cache, and the means for preserving said cache and its contents when said first virtual machine terminates is based on the record of the one operational user for said cache.

11. A system as set forth in claim 9 further comprising:

means, responsive to said virtual machine requesting an attachment to said cache, for recording that said virtual machine is a user of said cache; and

a second virtual machine and means for requesting an attachment of said second virtual machine to said cache, and in response, recording that said second virtual machine is another user of said cache.

12. A system as set forth in claim 9 further comprising:

means for said virtual machine making a request to a hypervisor of said virtual machine to attach to said cache and preserve said cache in case said virtual machine terminates, and in response, said hypervisor including means for defining a table which correlates to said cache virtual addresses used by said virtual machine for said cache, said table surviving termination of said virtual machine, whereby said cache is preserved in case of termination of said virtual machine.

13. A system as set forth in claim 12 further comprising:

another virtual machine on a same real computer as the first said virtual machine, and means for said other virtual machine making a request to said hypervisor to attach to another cache but not preserve said other cache in case said other virtual machine terminates, and in response, said hypervisor including means for defining another table which correlates to said other cache virtual addresses used by said other virtual machine for said other cache, said other table being deleted upon termination of said other virtual machine, whereby said other cache is deleted in case of termination of said other virtual machine.

14. A system as set forth in claim 9 further comprising:

said virtual machine including means for making a request to a hypervisor of said virtual machine to attach to said cache and preserve said cache in case said virtual machine terminates, and in response, said hypervisor including means for making a record that said cache should be preserved in case of termination of said virtual machine, and when said virtual machine terminates, said hypervisor preserving said cache and contents of said cache, such that if said virtual machine resumes operation, said virtual machine can access said cache and said contents.

15. A system as set forth in claim 14 further comprising:

means for said virtual machine resuming operation; and

means, responsive to resumption of operation of said virtual machine, for restoring to said virtual machine access to said cache and said contents.

16. A system as set forth in claim 9 further comprising:

means for said virtual machine resuming operation; and

means, responsive to resumption of said virtual machine, for restoring to said virtual machine access to said cache and said contents.

17. A computer program product for managing a cache of a virtual machine, said computer program product comprising:

a computer readable medium;

first program instructions to define a cache in memory, assign said cache to a virtual machine, and record an identity of said cache in storage; and

second program instructions to cause said virtual machine to terminate, and preserve said cache and contents of said cache despite said termination of said virtual machine, such that if said virtual machine subsequently resumes operating, said virtual machine can access said cache and said contents; and

wherein

said first and second program instructions are recorded on said medium.

18. A method for managing a cache of an LPAR, said method comprising the steps of:

defining a cache in memory, assigning said cache to an LPAR, and recording an identity of said cache in storage; and

said LPAR terminating, and preserving said cache and contents of said cache despite said termination of said LPAR, such that if said LPAR subsequently resumes operating, said LPAR can access said cache and said contents.

19. A method as set forth in claim 18 further comprising the steps of:

defining a second LPAR on a same real computer as the first said LPAR;

recording that both said first and second LPARs are users of said cache, such that when said first LPAR terminates, there is still one operational user recorded for said cache, and the step of preserving said cache and its contents when said first LPAR terminates is based on the record of the one operational user for said cache,.

20. A method as set forth in claim 18 further comprising the steps of:

said LPAR requesting an attachment to said cache, and in response, recording that said LPAR is a user of said cache; and

a second LPAR requesting an attachment to said cache, and in response, recording that said second LPAR is another user of said cache.

21. A method as set forth in claim 18 further comprising the subsequent steps of:

said LPAR resuming operation; and

restoring to said LPAR access to said cache and said contents.