Cluster-wide read-copy update system and method

• US 20060117072A1
• Filed: 11/30/2004
• Published: 06/01/2006
• Est. Priority Date: 11/30/2004
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Satran, Julian, McKenney, Paul E.
• Granted Patent: US 8,126,843 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 16/273 Asynchronous replication or reconciliation

Abstract

A system, method and computer program product for synchronizing updates to shared mutable data in a clustered data processing system. A data element update operation is performed at each node of the cluster while preserving a pre-update view of the shared mutable data, or an associated operational mode, on behalf of readers that may be utilizing the pre-update view. A request is made for detection of a grace period, and grace period detection processing is performed for detecting when the cluster-wide grace period has occurred. When it does, a deferred action associated with the update operation it taken, such as removal of a pre-update view of the data element or termination of an associated mode of operation.

Claims

1. A method for synchronizing data updates in a clustered data processing system, comprising:

performing a data element update operation at each node of said clustered data processing system while preserving a pre-update view of said shared mutable data, or an associated operational mode, on behalf of readers that may be utilizing said pre-update view;

requesting detection of a grace period;

detecting when a cluster-wide grace period has occurred; and

performing a deferred action associated with said update operation following detection of said cluster-wide grace period.

2. A method in accordance with claim 1, wherein said update operation is initially performed at an update-initiating node followed by other nodes in said clustered data processing system.

3. A method in accordance with claim 2, wherein said update-initiating node advises said other nodes of said update.

4. A method in accordance with claim 1, wherein said requesting comprises registering a callback at each node.

5. A method in accordance with claim 1, wherein said cluster-wide grace period detection is performed by an update-initiating node.

6. A method in accordance with claim 5, wherein said cluster-wide grace period detection is performed by said update-initiating node receiving reports from other nodes in said clustered data processing system passing through local grace periods or quiescent states.

7. A method in accordance with claim 1, wherein said cluster-wide grace period detection is performed at all nodes of said clustered data processing system.

8. A method in accordance with claim 7, wherein said cluster-wide grace period detection is performed by each node of said clustered data processing system maintaining a count of nodes passing through local grace periods or quiescent states.

9. A method in accordance with claim 1, wherein said cluster-wide grace period is based on all nodes in said clustered data processing system passing through a local grace period.

10. A method in accordance with claim 1, wherein said cluster-wide grace period is based on all nodes in said clustered data processing system passing through a local quiescent state.

11. A clustered data processing system having plural data processing nodes, said system being adapted to synchronize date updates, and comprising:

update means for performing a data element update operation at each node of said clustered data processing system while preserving a pre-update view of said shared mutable data, or an associated operational mode, on behalf of readers that may be utilizing said pre-update view;

request means for requesting detection of a grace period;

grace period detecting means for detecting when a cluster-wide grace period has occurred; and

removal means for performing a deferred action associated with said update operation following detection of said cluster-wide grace period.

12. A system in accordance with claim 11, wherein said update means comprises initially performing an update operation at an update-initiating node followed by other nodes in said clustered data processing system.

13. A system in accordance with claim 12, wherein said update-initiating node is adapted to advise said other nodes of said update.

14. A system in accordance with claim 11, wherein said request means comprises callback registration means at each node.

15. A system in accordance with claim 11, wherein said grace period detecting means is associated with said update-initiating node.

16. A system in accordance with claim 15, wherein said grace period detecting means comprises means associated with said update-initiating node for receiving reports from other nodes in said clustered data processing system passing through local grace periods or quiescent states.

17. A system in accordance with claim 11, wherein said grace period detecting means comprises means for performing cluster-wide grace period detection at all nodes of said clustered data processing system.

18. A system in accordance with claim 17, wherein said grace period detecting means comprises means associated with each node of said clustered data processing system for maintaining a count of nodes passing through local grace periods or quiescent states.

19. A system in accordance with claim 11, wherein said cluster-wide grace period is based on all nodes in said clustered data processing system passing through a local grace period.

20. A system in accordance with claim 12, wherein said cluster-wide grace period is based on all nodes in said clustered data processing system passing through a local quiescent state.

21. A computer program product for synchronizing updates to shared mutable data in a clustered data processing system, comprising:

one or more data storage media;

means recorded on said data storage media for programming a data processing platform to operate as by;

performing a data element update operation at each node of said clustered data processing system while preserving a pre-update view of said shared mutable data, or an associated operational mode, on behalf of readers that may be utilizing said pre-update view;

requesting detection of a grace period;

detecting when a cluster-wide grace period has occurred; and

performing a deferred action associated with said update operation following detection of said cluster-wide grace period.

22. A computer program product in accordance with claim 21, wherein said update operation is initially performed at an update-initiating node followed by other nodes in said clustered data processing system.

23. A computer program product in accordance with claim 22, wherein said update-initiating node advises said other nodes of said update.

24. A computer program product in accordance with claim 21, wherein said requesting comprises registering a callback at each node.

25. A computer program product in accordance with claim 21, wherein said cluster-wide grace period detection is performed by an update-initiating node.

26. A computer program product in accordance with claim 25, wherein said cluster-wide grace period detection is performed by said update-initiating node receiving reports from other nodes in said clustered data processing system passing through local grace periods or quiescent states.

27. A computer program product in accordance with claim 21, wherein said cluster-wide grace period detection is performed at all nodes of said clustered data processing system.

28. A computer program product in accordance with claim 27, wherein said cluster-wide grace period detection is performed by each node of said clustered data processing system maintaining a count of nodes passing through local grace periods or quiescent states.

29. A computer program product in accordance with claim 21, wherein said cluster-wide grace period is based on all nodes in said clustered data processing system passing through a local grace period.

30. A computer program product in accordance with claim 21, wherein said cluster-wide grace period is based on all nodes in said clustered data processing system passing through a local quiescent state.