Method and apparatus for managing a memory system

• US 20040098544A1
• Filed: 11/15/2002
• Published: 05/20/2004
• Est. Priority Date: 11/15/2002
• Status: Abandoned Application

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Osecky, Benjamin D., Gaither, Blaine D.
• Application Number:
  US10/294,718
• Publication Number:
  US 20040098544A1
• Time in Patent Office: Days
• US Class Current: 711/154
• CPC Class Codes: G06F 12/023 Free address space management
• CPC Class Codes: G06F 12/10 Address translation
• CPC Class Codes: G06F 2212/401 Compressed data

Abstract

In a method of managing memory, a plurality of check values are generated from contents of memory. Each check value is associated with a respective page in a memory system in a data structure. The data structure is searched for a candidate page having identical content to a requesting page in the memory system by utilizing a check value of the requested page in the search.

Claims

1. A method for managing a memory system, comprising:

generating a plurality of check values from contents of memory;

associating each check value of said plurality of check values to a respective page in said memory system in a data structure; and

searching said data structure for a candidate page having identical content to a requesting page in said memory system, wherein a check value of said requested page is used to search said data structure.

2. The method according to claim 1, further comprising:

comparing said requested page with said candidate page in a byte-by-byte manner in response to said check value of said requested page matching associated check value of said candidate page.

3. The method according to claim 2, further comprising:

linking said requested page and said candidate page in response to said content of said requested page and said content of said candidate page being identical.

4. The method according to claim 3, further comprising:

storing an indicator configured to identify said mapping of said requested page and said candidate page.

5. The method according to claim 1, wherein said check value is a checksum value or a hash value.

6. The method according to claim 1, wherein said check value is retrieved from an external source.

7. The method according to claim 1, wherein said searching of said data structure for said candidate page utilizes a subset of one of said checksum value or said hash value.

8. The method according to claim 1, wherein searching said data structure for said candidate page in said memory system is invoked in response to a storage of said requested page in said memory system.

9. The method according to claim 1, wherein searching said data structure for said candidate page in said memory system is invoked periodically.

10. The method according to claim 1, wherein searching said data structure for said identical page in a partition of said memory system.

11. The method according to claim 1, further comprising:

adding said requested page and said check value of said requested page to said data structure; and

forming an association between said requested page and said check value of said requested page.

12. An apparatus for managing access to memory subsystems, comprising:

a memory adapted to provide storage for a plurality of processors; and

a virtual compression system (VCS) configured to divide said memory system into a plurality of partitions, each partition being assigned to a respective subset of processors of said plurality of processors, wherein said VCS is also configured to receive a virtual address from a selected processor of said subset of processors, to identify a partition, and to translate said virtual address to a real address within a respective partition of said selected processor.

13. The apparatus according to claim 12, further comprising:

a free page pool configured to provide a list of available pages of said memory, where said available pages are not accessible by said plurality of partitions.

14. The apparatus according to claim 12, further comprising:

a global table configured to associate pages of said memory system with respective pages of said plurality of partitions.

15. The apparatus according to claim 12, further comprising:

a frame page table configured to each page of said plurality of pages in said memory system with a respective entry is in said frame page table.

16. The apparatus according to claim 15, wherein each entry in said frame page table comprises a reference counter configured to indicate that said respective entry is shared among a sub-plurality of partitions of said plurality of partitions.

17. The apparatus according to claim 12, further comprising:

a hash table configured to store a respective hash value computed from the content of each page for each page of said plurality of pages of said memory system.

18. The apparatus according to claim 12, wherein said VCS is adapted to be integrated with a personal computer platform, a workstation platform, a server platform, a microprocessor chip support set, a storage platform, a cache controller, and a disk controller.

19. A method for managing a memory, comprising:

comparing a check value computed from a content of a selected page with respective check values of a plurality of pages of said memory;

selecting a matching page in response to said check value and a respective check value of said matching page being equal;

comparing said selected page and said matching page; and

redirecting a virtual address of one of said selected page and said matching page to a physical address of other one of said selected page and said matching page in response to said selected page and said matching page being identical in content.

20. The method according to claim 19, further comprising:

de-referencing one of said selected page and said matching page; and

placing said de-referenced page on a free page pool.

21. The method according to claim 20, wherein said selected page and said matching page are associated with a single partition of plurality of partitions.

22. The method according to claim 20, wherein said selected page and said matching page are associated with said memory.

23. A method of managing a memory, comprising:

writing data to a selected page of said memory;

determining a status of said selected page;

requesting a page from a free page pool of said memory in response to said selected page being shared;

writing contents of said selected page onto said requested page;

generating a hash value based on respective content of said requested page; and

searching for other pages based on said hash value.

24. An apparatus for managing memory, said apparatus comprising:

means for writing data to a selected page of said memory;

means for determining a status of said selected page;

means for requesting a page from a free page pool of said memory in response to said selected page being shared;

means for writing contents of said selected page onto said requested page;

means for generating a hash value based on respective content of said requested page; and

means for searching for other pages based on said hash value.