Apparatus and method for restarting a shared virtual resource

• US 20050108456A1
• Filed: 11/13/2003
• Published: 05/19/2005
• Est. Priority Date: 11/13/2003
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Boutcher, David Charles, DeVilbiss, Colin Robert
• Granted Patent: US 7,587,723 B2
• Time in Patent Office: Days
• US Class Current: 710/240
• CPC Class Codes: G06F 2009/45575 Starting, stopping, suspending or resuming virtual machine instances
• CPC Class Codes: G06F 9/45558 Hypervisor-specific management and integration aspects

Abstract

An apparatus and method provide a protocol for communicating between an operating system that owns a shared resource and other operating systems that use the shared resource so that the operating systems that use the shared resource will not crash if the operating system that owns the shared resource is restarted. Messages are defined that allow handshaking between operating systems so that operating systems that share a resource will realize the resource will be unavailable for some period of time, and that allow resuming the sharing of the resource once the operating system that owns the shared resource is restarted.

Claims

1. An apparatus comprising:

at least one processor;

a memory coupled to the at least one processor;

a pause/resume mechanism residing in the memory and executed by the at least one processor, the pause/resume mechanism sending a pause message when a first operating system needs to be restarted to at least one other operating system that is using a shared resource that is also used by the first operating system, the pause/resume mechanism sending a resume message to the at least one other operating system after the first operating system is restarted.

2. The apparatus of claim 1 wherein the pause/resume mechanism receives a pause complete message from each other operating system to indicate each other operating system has completed pending accesses to the shared resource.

3. The apparatus of claim 1 wherein the pause/resume mechanism disconnects the first operating system from the second operating system before the first operating system is restarted.

4. The apparatus of claim 1 wherein the pause/resume mechanism reconnects the first operating system to the at least one other operating system after the first operating system is restarted.

5. The apparatus of claim 1 wherein the resume message indicates that the first operating system is ready to resume sharing the shared resource with the at least one other operating system.

6. A computer system comprising:

a first operating system residing in a memory, the first operating system owning a shared resource;

a second operating system residing in the memory, the second operating system using the share resource;

a pause/resume mechanism residing in the memory, the pause/resume mechanism sending a pause message to the second operating system when the first operating system needs to be restarted, the pause/resume mechanism sending a resume message to the second operating system after the first operating system is restarted.

7. The computer system of claim 6 further comprising a plurality of operating systems that use the shared resource, wherein the pause/resume mechanism sends the pause message and the resume message to the plurality of operating systems.

8. The computer system of claim 6 wherein the pause/resume mechanism receives a pause complete message from the second operating system to indicate the second operating system has completed pending accesses to the shared resource.

9. The computer system of claim 6 wherein the pause/resume mechanism disconnects the first operating system from the the second operating system before the first operating system is restarted.

10. The computer system of claim 6 wherein the pause/resume mechanism reconnects the first operating system and the second operating system after the first operating system is restarted.

11. The computer system of claim 6 wherein the resume message indicates that the first operating system is ready to resume sharing the shared resource with the second operating system.

12. A computer system comprising:

a first operating system residing in a memory, the first operating system owning a shared resource;

a second operating system residing in the memory, the second operating system using the share resource;

the first operating system comprising a pause/resume mechanism that sends a pause message to the second operating system when the first operating system needs to be restarted, that receives a pause complete message from the second operating system to indicate the second operating system has completed pending accesses to the shared resource, that sends a disconnect message to the second operating system before the first operating system is restarted, that sends a connect message to the second operating system after the first operating system is restarted to inform the second operating system that the first operating system has been restarted, and that sends a resume message to the second operating system after the first operating system is restarted to indicate to the second operating system that the first operating system is ready to resume sharing the shared resource with the second operating system.

13. A computer-implemented method for sharing a shared resource between a first operating system and at least one other operating system, the method comprising the steps of:

sending a pause message when the first operating system needs to be restarted to the at least one other operating system; and

sending a resume message to the at least one other operating system after the first operating system is restarted.

14. The method of claim 13 further comprising the step of receiving a pause complete message from each other operating system to indicate each other operating system has completed pending accesses to the shared resource.

15. The method of claim 13 further comprising the step of disconnecting the first operating system from the at least one other operating system before the first operating system is restarted.

16. The method of claim 13 further comprising the step of reconnecting the first operating system to the at least one other operating system after the first operating system is restarted.

17. The method of claim 13 wherein the resume message indicates that the first operating system is ready to resume sharing the shared resource with the at least one other operating system.

18. A computer-implemented method for sharing a shared resource owned by a first operating system with a second operating system, the method comprising the steps of:

(A) sending a pause message to the second operating system when the first operating system needs to be restarted; and

(B) sending a resume message to the second operating system after the first operating system is restarted.

19. The method of claim 18 further comprising the step of:

a plurality of operating systems using the shared resource, wherein step (A) sends the pause message to the plurality of operating systems, and wherein step (B) sends the resume message to the plurality of operating systems.

20. The method of claim 18 further comprising the step of receiving a pause complete message from the second operating system to indicate the second operating system has completed pending accesses to the shared resource.

21. The method of claim 18 further comprising the step of disconnecting the first operating system from the second operating system before the first operating system is restarted.

22. The method of claim 18 further comprising the step of reconnecting the first operating system to the second operating system after the first operating system is restarted.

23. The method of claim 18 wherein the resume message indicates that the first operating system is ready to resume sharing the shared resource with the second operating system.

24. A computer-implemented method for sharing a shared resource between a first operating system and a second operating system, the method comprising the steps of:

the first operating system sending a pause message to the second operating system when the first operating system needs to be restarted;

the second operating system sending a pause complete message to the first operating system to indicate the second operating system has completed pending accesses to the shared resource;

the first operating system sending a disconnect message to the second operating system before the first operating system is restarted;

the first operating system sending a connect message to the second operating system after the first operating system is restarted to inform the second operating system that the first operating system has been restarted; and

the first operating system sending a resume message to the second operating system after the first operating system is restarted to indicate to the second operating system that the first operating system is ready to resume sharing the shared resource with the second operating system.

25. A program product comprising:

(A) a pause/resume mechanism that sends a pause message when a first operating system needs to be restarted to at least one other operating system that is using a shared resource that is also used by the first operating system, the pause/resume mechanism sending a resume message to the at least one other operating system after the first operating system is restarted; and

(B) computer readable signal bearing media bearing the pause/resume mechanism.

26. The program product of claim 25 wherein the signal bearing media comprises recordable media.

27. The program product of claim 25 wherein the signal bearing media comprises transmission media.

28. The program product of claim 25 wherein the pause/resume mechanism receives a pause complete message from each other operating system to indicate each other operating system has completed pending accesses to the shared resource.

29. The program product of claim 25 wherein the pause/resume mechanism disconnects the first operating system from the at least one other operating system before the first operating system is restarted.

30. The program product of claim 25 wherein the pause/resume mechanism reconnects the first operating system to the at least one other operating system after the first operating system is restarted.

31. The program product of claim 25 wherein the resume message indicates that the first operating system is ready to resume sharing the shared resource with the at least one other operating system.

32. A program product comprising:

a pause/resume mechanism that sends a pause message to a second operating system when a first operating system needs to be restarted and that sends a resume message to the second operating system after the first operating system is restarted; and

(B) computer readable signal bearing media bearing the pause/resume mechanism.

33. The program product of claim 32 wherein the signal bearing media comprises recordable media.

34. The program product of claim 32 wherein the signal bearing media comprises transmission media.

35. The program product of claim 32 wherein a plurality of operating systems use the shared resource, wherein the pause/resume mechanism sends the pause message and the resume message to the plurality of operating systems.

36. The program product of claim 32 wherein the pause/resume mechanism receives a pause complete message from the second operating system to indicate the second operating system has completed pending accesses to the shared resource.

37. The program product of claim 32 wherein the pause/resume mechanism disconnects the first operating system from the second operating system before the first operating system is restarted.

38. The program product of claim 32 wherein the pause/resume mechanism reconnects the first operating system to the second operating system after the first operating system is restarted.

39. The program product of claim 32 wherein the resume message indicates that the first operating system is ready to resume sharing the shared resource with the second operating system.

40. A program product comprising:

a pause/resume mechanism that sends a pause message to a second operating system when a first operating system needs to be restarted, that receives a pause complete message from the second operating system to indicate the second operating system has completed pending accesses to a shared resource, that sends a disconnect message to the second operating system before the first operating system is restarted, that sends a connect message to the second operating system after the first operating system is restarted to inform the second operating system that the first operating system has been restarted, and that sends a resume message to the second operating system after the first operating system is restarted to indicate to the second operating system that the first operating system is ready to resume sharing the shared resource with the second operating system; and

(B) computer readable signal bearing media bearing the pause/resume mechanism.

41. The program product of claim 40 wherein the signal bearing media comprises recordable media.

42. The program product of claim 40 wherein the signal bearing media comprises transmission media.