Method for improving disk space allocation

• US 20050262325A1
• Filed: 05/21/2004
• Published: 11/24/2005
• Est. Priority Date: 05/21/2004
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Seeger, James J. Jr., Shmueli, Boaz, Young, Jason C.
• Granted Patent: US 7,409,518 B2
• Time in Patent Office: Days
• US Class Current: 711/170
• CPC Class Codes: G06F 3/0608 Saving storage space on storage systems
• CPC Class Codes: G06F 3/0631 by allocating resources to storage systems
• CPC Class Codes: G06F 3/0644 Management of space entities, e.g. partitions, extents, pools
• CPC Class Codes: G06F 3/0676 Magnetic disk device
• CPC Class Codes: G06F 9/5016 the resource being the memory

Abstract

A method and system for allocating blocks of disk in persistent storage to requesting threads. A primary data structure is provided for organizing and categorizing blocks of disk space. In addition, a secondary data structure is provided for maintaining a list of all active file system processes and blocks of disk space used by those processes. Blocks of disk space are assigned to pages. At such time as a thread may request allocation of disk space, both data structures are reviewed to determine if the requested disk space is available and to limit access of available disk space to a single page of memory to a single thread at any one time.

Claims

1. A method for allocating storage space comprising:

(a) maintaining a list of available runs of blocks of persistent memory in a primary data structure;

(b) categorizing said runs of blocks in said primary data structure according to length; and

(c) coordinating allocation of said categorized runs of blocks between said primary data structure and a thread.

2. The method of claim 1, further comprising maintaining a secondary data structure in communication with said primary data structure, wherein said secondary data stricture includes a list of all active file system processes and blocks used by said processes.

3. The method of claim 2, wherein each active file system process includes a pointer to a bitmap page assigned to a run block of persistent memory.

4. The method of claim 3, further limiting access to said bitmap page assigned to said block to a single thread.

5. The method of claim 1, wherein the step of coordinating allocation of said block between said primary data structure and a thread includes scanning said blocks and adding an entry of available blocks to said primary data structure.

6. The method of claim 5, further comprising terminating said scan based upon criteria selected from a group consisting of:

said primary data structure is full, and entire memory space has been scanned.

7. The method of claim 1, wherein the step of coordinating allocation of said categorized block between said primary data structure and thread includes an organization step selected from a group consisting of:

allocating said blocks to a requesting thread, and adding expired blocks to said primary data structure.

8. A computer system comprising:

a primary data structure adapted to maintain a list of available runs of blocks of persistent memory;

a manager adapted to categorize said runs of blocks according to length; and

a coordinator adapted to allocate said categorized blocks between said primary data structure and a thread.

9. The system of claim 8, further comprising a secondary data structure in communication with said primary data structure adapted to maintain a list of all active file system processes and blocks used by said processes.

10. The system of claim 9, wherein said active file system processes include a pointer to a bitmap page assigned to a run block of persistent memory.

11. The system of claim 10, wherein said coordinator is adapted to limit access to said bitmap page assigned to said block to a single thread.

12. The system of claim 8, wherein said coordinator is adapted to scan said blocks and add an entry of available blocks to said primary data structure.

13. The system of claim 12, wherein said scan is adapted to be terminated in response to criteria selected from a group consisting of:

said primary data structure is full, and entire memory space has been scanned.

14. The system of claim 8, wherein said coordinator is adapted to organize an action selected from a group consisting of:

allocation of a block to a requesting thread, and addition of an expired block to said primary data structure.

15. An article comprising:

a computer-readable signal-bearing medium;

means in the medium for maintaining a list of available runs of blocks of persistent memory;

means in the medium for categorizing said runs of blocks in said primary data structure; and

means in the medium for coordinating allocation of said categorized blocks between said primary data structure and a thread.

16. The article of claim 15, wherein the medium is selected from a group consisting of:

a recordable data storage medium, and a modulated carrier signal.

17. The article of claim 15, further comprising means in the medium for maintaining a list of all active file system processes and blocks used by said processes.

18. The article of claim 17, wherein said file system process includes a pointer to a bitmap page assigned to a run block of persistent memory.

19. The article of claim 18, further comprising means in the medium for limited access to said bitmap page assigned to said block to a single thread.

20. The article of claim 15, wherein said means for coordinating allocation of said categorized blocks between said primary data structure and a thread is adapted to organize an action selected from a group consisting of:

allocation of a block to a requesting thread, and addition of an expired block to said primary data structure.

21. A method for allocating storage space comprising:

(a) maintaining a list of available runs of blocks of persistent memory in a primary data structure;

(b) categorizing said runs of blocks in said primary data structure according to length;

(c) coordinating allocation of said categorized runs of blocks between said primary data structure and a thread; and

(d) maintaining a secondary data structure in communication with said primary data structure, wherein said secondary data structure includes a list of all active file system processes and blocks used by said processes.