Method for improving disk space allocation

• US 7,409,518 B2
• Filed: 05/21/2004
• Issued: 08/05/2008
• Est. Priority Date: 05/21/2004
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Seeger, James J. Jr., Shmueli, Boaz, Young, Jason C.
• Primary Examiner(s): Kim; Matt
• Assistant Examiner(s): Krofcheck; Michael C
• Application Number:
  US10/850,927
• Publication Number:
  US 20050262325A1
• Time in Patent Office: 1,537 Days
• Field of Search: 711/170
• 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:

maintaining a list of available run of blocks of persistent memory in a primary data structure;

categorizing said run of blocks in said primary data structure according to length;

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;

categorizing said run of blocks in a secondary data structure according to page lengths of said run of blocks and active threads for each associated page;

coordinating allocation of said categorized run of blocks between said primary data structure, said secondary data structure, and a thread;

denying access of multiple requesting threads to a run of blocks based on a prior thread allocation; and

allocating a run of blocks to a requesting thread in response to availability of said run in said primary data structure and said secondary data structure.

2. The method of claim 1, wherein each active file system process includes a pointer to a bitmap page assigned to a run block of persistent memory.

3. 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.

4. The method of claim 3, 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.

5. 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.

6. The method of claim 1, wherein the run of blocks based on a prior thread allocation is reflected in said secondary data structure.

7. A method for allocating storage space comprising:

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

categorizing said run of blocks in said primary data structure according to length;

coordinating allocation of said categorized run of blocks between said primary data structure and a thread;

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;

denying access to said run of blocks from a requesting thread based upon a conflicting prior access to said blocks; and

allocating said run of blocks to a requesting thread in response to availability of said run in said primary and secondary data structures.