System and method for maintaining solvency within a cache

• US 9,549,037 B2
• Filed: 08/07/2012
• Issued: 01/17/2017
• Est. Priority Date: 08/07/2012
• Status: Active Grant

• Current Assignee: Dell Products BV (Dell Technologies Inc.)
• Original Assignee: Dell Products LP (Dell Technologies Inc.)
• Inventors: Krueger, Phillip E., Shaffer, Christopher August
• Primary Examiner(s): Parry, Chris
• Assistant Examiner(s): STILTNER, WEIWEI YE
• Application Number:
  US13/568,795
• Publication Number:
  US 20140047062A1
• Time in Patent Office: 1,624 Days
• Field of Search: 709/216
• US Class Current: 1/1
• CPC Class Codes: G06F 12/023 Free address space management
• CPC Class Codes: G06F 12/0804 with main memory updating G06F12/0806 takes precedence
• CPC Class Codes: G06F 12/0815 Cache consistency protocols
• CPC Class Codes: G06F 12/0866 for peripheral storage systems, e.g. disk cache
• CPC Class Codes: G06F 2212/466 Metadata, control data
• CPC Class Codes: G06F 3/0652 Erasing, e.g. deleting, data cleaning, moving of data to a wastebasket
• CPC Class Codes: H04L 67/1097 for distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS]
• CPC Class Codes: H04L 67/568 Storing data temporarily at an intermediate stage, e.g. caching
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

In one embodiment, a computing system includes a cache including one or more memories and a cache manager. The cache manager is able to determine an amount of accessible data for a portion of the cache associated with the cache manager; compare the amount of accessible data to a threshold value; determine, for one or more clients associated with the cache manager, an amount of releasable data if the amount of accessible data exceeds the threshold value; communicate, to one or more clients associated with the cache manager, the amount of releasable data for the client; receive from one or more clients associated with the cache manager information associated with data released by the one or more clients; and determine an amount of data released by the one or more clients associated with the cache manager.

Claims

1. A method comprising:

determining, at a cache manager, an amount of accessible data for a portion of a cache associated with the cache manager, wherein determining the amount of accessible data occurs independently of a request by a client to read or write data to the portion of the cache;

comparing the amount of accessible data to a first threshold value and a second threshold value, wherein the second threshold value is greater than the first threshold value;

determining, for one or more clients associated with the cache manager, an amount of releasable data if the amount of accessible data exceeds one of the first threshold value and the second threshold value;

precluding, if the amount of accessible data exceeds the second threshold value, one or more clients associated with the cache manager from writing to the portion of the cache;

communicating, to one or more clients associated with the cache manager, a request for the one or more clients to release the amount of releasable data for the respective client;

receiving, from one or more clients associated with the cache manager, information associated with data requested to be released by the one or more clients; and

determining, at the cache manager, an amount of data released by the one or more clients associated with the cache manager.

2. The method of claim 1, wherein the amount of accessible data is the amount of data to which one or more clients associated with the cache manager hold a read reference or a write reference.

3. The method of claim 1, wherein each of the first threshold value and the second threshold value represents an amount of data that is not greater than 70% of the size of the portion of the cache associated with the cache manager.

4. The method of claim 1, wherein the total amount of releasable data for all clients associated with the cache manager is the amount by which the amount of accessible data exceeds the first threshold value.

5. The method of claim 1, wherein data released by the one or more clients includes data to which the one or more clients no longer hold a read reference or a write reference.

6. The method of claim 1, further comprising:

determining, at the cache manager, a second amount of accessible data for the portion of the cache associated with the cache manager; and

comparing the second amount of accessible data to the first threshold value and the second threshold value.

7. One or more computer-readable non-transitory storage media embodying logic that is operable when executed to:

determine, at a cache manager comprising the one or more computer-readable non-transitory storage media, an amount of accessible data for a portion of a cache associated with the cache manager, wherein the determination of the amount of accessible data occurs independently of a request by a client to read or write data to the portion of the cache;

compare the amount of accessible data to a first threshold value and a second threshold value, wherein the second threshold value is greater than the first threshold value;

determine, for each of one or more clients associated with the cache manager, an amount of releasable data if the amount of accessible data exceeds the first threshold value;

precluding, if the amount of accessible data exceeds the second threshold value, one or more clients associated with the cache manager from writing to the portion of the cache;

communicate, to each client associated with the cache manager, a request for the client to release the amount of releasable data for the respective client;

receive, from each client associated with the cache manager, information associated with data requested to be released by the one or more clients;

determine, at the cache manager, an amount of data released by the one or more clients associated with the cache manager.

8. The media of claim 7, wherein the amount of accessible data is the amount of data to which one or more clients associated with the cache manager hold a read reference or a write reference.

9. The media of claim 7, wherein each of the first threshold value and the second threshold value represents an amount of data that is not greater than 70% of the size of the portion of the cache associated with the cache manager.

10. The media of claim 7, wherein the total amount of releasable data for all clients associated with the cache manager is the amount by which the amount of accessible data exceeds the first threshold value.

11. The media of claim 7, wherein data released by the one or more clients includes data to which the one or more clients no longer hold a read reference or a write reference.

12. The media of claim 7, the logic further operable when executed to:

determine, at the cache manager, a second amount of accessible data for the portion of the cache associated with the cache manager; and

compare the second amount of accessible data to the first threshold value and the second threshold value.

13. A computing system, comprising:

a cache comprising one or more memories; and

a cache manager; and

wherein the cache manager is operable to;

determine an amount of accessible data for a portion of the cache associated with the cache manager, wherein the determination of the amount of accessible data occurs independently of a request by a client to read or write data to the portion of the cache;

compare the amount of accessible data to a first threshold value and a second threshold value, wherein the second threshold value is greater than the first threshold value;

determine, for one or more clients associated with the cache manager, an amount of releasable data if the amount of accessible data exceeds the first threshold value;

precluding, if the amount of accessible data exceeds the second threshold value, one or more clients associated with the cache manager from writing to the portion of the cache;

communicate, to one or more clients associated with the cache manager, a request for the one or more clients to release the amount of releasable data for the client;

receive, from one or more clients associated with the cache manager, information associated with data requested to be released by the one or more clients; and

determine an amount of data released by the one or more clients associated with the cache manager.

14. The system of claim 13, wherein the amount of accessible data is the amount of data to which one or more clients associated with the cache manager hold a read reference or a write reference.

15. The system of claim 13, wherein each of the first threshold value and the second threshold value represents an amount of data that is not greater than 70% of the size of the portion of the cache associated with the cache manager.

16. The system of claim 13, wherein the total amount of releasable data for all clients associated with the cache manager is the amount by which the amount of accessible data exceeds the first threshold value.

17. The system of claim 13, wherein data released by the one or more clients includes data to which the one or more clients no longer hold a read reference or a write reference.

18. The system of claim 13, the cache manager further operable to:

determine a second amount of accessible data for the portion of the cache associated with the cache manager; and

compare the second amount of accessible data to the first threshold value and the second threshold value.

19. The system of claim 13, wherein each of the first threshold value and the second threshold value represents an amount of data that is not greater than 90% of the size of the portion of the cache associated with the cache manager.

20. The system of claim 13, wherein each of the first threshold value and the second threshold value represents an amount of data that is not greater than 50% of the size of the portion of the cache associated with the cache manager.