IMPLEMENTING ENHANCED DETERMINISTIC MEMORY ALLOCATION FOR INDIRECTION TABLES FOR PERSISTENT MEDIA

• US 20120303928A1
• Filed: 08/11/2011
• Published: 11/29/2012
• Est. Priority Date: 05/23/2011
• Status: Active Grant

• Current Assignee: JP Morgan Chase Bank, N.A. (JP Morgan Chase & Co)
• Original Assignee: Hitachi Global Storage Technologies Netherlands BV (Western Digital Corporation)
• Inventors: Hall, David Robison
• Granted Patent: US 8,788,749 B2
• Time in Patent Office: Days
• US Class Current: 711/172
• CPC Class Codes: G11B 5/012 Recording on, or reproducing or erasing from, magnetic disks G11B17/00, G11B19/00 take precedence

Abstract

A method and a storage system are provided for implementing deterministic memory allocation for indirection tables for persistent media or disk drives, such as, shingled perpendicular magnetic recording (SMR) indirection tables. A plurality of fixed-size memory pools are used to store indirection data. The distribution of pool allocate sizes is fixed. A pool allocate size is selected based upon an indirection system request size.

Claims

1. A method for implementing deterministic memory allocation for indirection tables for persistent media comprising:

using a plurality of fixed-size memory pools to store indirection data;

a distribution of pool allocate sizes being fixed; and

selecting a pool allocate size based upon an indirection system request size.

2. The method as recited in claim 1 wherein the persistent media includes a Shingled Disk Drive.

3. The method as recited in claim 1 wherein using a plurality of fixed-size memory pools to store indirection data includes providing indirection tables memory allocation control logic coupled to a controller to control storing of the indirection data.

4. The method as recited in claim 1 wherein using a plurality of fixed-size memory pools to store indirection data includes providing a head pointer to identify a memory pool target address.

5. The method as recited in claim 4 includes providing next pointers using a first word of each free allocation.

6. The method as recited in claim 1 wherein selecting a pool allocate size based upon an indirection system request size includes providing a pool manager for returning an allocation using an index for the distribution of pool allocate sizes.

7. The method as recited in claim 6 includes identifying the index equal to said request size divided by an allocation granularity minus one.

8. The method as recited in claim 6 includes using an index for the distribution of pool allocate sizes includes identifying the index and using direct addressing for returning the allocation.

9. The method as recited in claim 6 wherein using an index for the distribution of pool allocate sizes includes identifying an index and using indirect addressing for returning the allocation, with an entry equal to a biggest allocation divided by an allocation granularity.

10. The method as recited in claim 1 wherein using a plurality of fixed-size memory pools to store SMR indirection data further includes using one of said fixed-size memory pools to define a plurality of mini-pools with predefined bytes used as a chain pointer between the plurality of mini-pools.

11. An apparatus for implementing deterministic memory allocation for indirection tables for persistent media comprising:

a plurality of fixed-size memory pools for storing indirection data;

a distribution of pool allocate sizes being fixed; and

a pool manager selecting a pool allocate size based upon an indirection system request size.

12. The apparatus as recited in claim 11 wherein the persistent media includes a Shingled Disk Drive.

13. The apparatus as recited in claim 11 includes a controller, and indirection tables memory allocation control logic coupled to said controller to control storing of the indirection data in said plurality of fixed-size memory pools.

14. The apparatus as recited in claim 13 wherein said indirection tables memory allocation control logic coupled to said controller to control storing of the indirection data includes said indirection tables memory allocation control logic providing a head pointer to identify a memory pool target address of each of said plurality of fixed-size memory pools.

15. The apparatus as recited in claim 14 includes said indirection tables memory allocation control logic providing next pointers using a first word of each free allocation of each of said plurality of fixed-size memory pools.

16. The apparatus as recited in claim 11 wherein said pool manager selecting a pool allocate size based upon an indirection system request size returns an allocation using an index for the distribution of pool allocate sizes.

17. The apparatus as recited in claim 16 wherein said pool manager identifies the index equal to said request size divided by an allocation granularity minus one.

18. A data storage system comprising:

a persistent media;

a controller, and indirection tables memory allocation control logic coupled to said controller for implementing deterministic memory allocation for indirection tables;

said controller and indirection tables memory allocation control logic using a plurality of fixed-size memory pools for storing SMR indirection data;

a distribution of pool allocate sizes being fixed; and

a pool manager selecting a pool allocate size based upon an indirection system request size.

19. The data storage system as recited in claim 18 wherein said controller and SMR indirection tables memory allocation control logic using a plurality of fixed-size memory pools for storing indirection data includes said controller and indirection tables memory allocation control logic providing a head pointer to identify a memory pool target address and providing next pointers using a first word of each free allocation of each of said plurality of fixed-size memory pools.

20. The data storage system as recited in claim 18 wherein pool manager selecting a pool allocate size based upon an indirection system request size returns an allocation using an index for the distribution of pool allocate sizes;

said index equal to said request size divided by an allocation granularity minus one.