Non-volatile memory cache performance improvement

• US 8,255,645 B2
• Filed: 09/13/2011
• Issued: 08/28/2012
• Est. Priority Date: 05/03/2004
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Ergan, Cenk, Nicholson, Clark D., Teodosiu, Dan, DeWhitt, Dean L., Hill, Emily Nicole, Kodavalla, Hanumantha R., Zwilling, Michael J., Parchem, John M., Fortin, Michael R., Obr, Nathan Steven, Nagar, Rajeev Y., Verma, Surenda, Powell, Therron, Westerinen, William J., Zbikowski, Mark Joseph, Stemen, Patrick L.
• Primary Examiner(s): YU, JAE UN
• Application Number:
  US13/231,088
• Publication Number:
  US 20120005422A1
• Time in Patent Office: 350 Days
• Field of Search: 711/154, 711/156, 711/161, 711/162, 714/6.31
• US Class Current: 711/154
• CPC Class Codes: G06F 12/08 in hierarchically structured memory systems, e.g. virtual memory systems
• CPC Class Codes: G06F 12/0866 for peripheral storage systems, e.g. disk cache
• CPC Class Codes: G06F 2212/1016 Performance improvement
• CPC Class Codes: G06F 2212/222 Non-volatile memory
• CPC Class Codes: G06F 2212/281 Single cache
• CPC Class Codes: G06F 2212/305 being part of a memory device, e.g. cache DRAM
• CPC Class Codes: G06F 2212/312 In storage controller
• CPC Class Codes: G06F 2212/313 In storage device
• CPC Class Codes: G06F 3/061 Improving I/O performance
• CPC Class Codes: G06F 3/0656 Data buffering arrangements
• CPC Class Codes: G06F 3/0679 Non-volatile semiconductor memory device, e.g. flash memory, one time programmable memory [OTP]
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

In order to provide a more efficient persistent storage device, one or more long-term storage media are included along with a non-volatile memory. In one embodiment, one portion of the non-volatile memory is used as a write buffer and a read cache for writes and reads to the long-term storage media. Interfaces are provided for controlling the use of the non-volatile memory as a write buffer and a read cache. Additionally, a portion of the non-volatile memory is used to provide a direct mapping for specified sectors of the long-term storage media. Descriptive data regarding the persistent storage device is stored in another portion of the non-volatile memory.

Claims

1. A method of operating a computer system having a non-volatile memory and a long-term storage medium, the method comprising:

defining, in said non-volatile memory, a mapped portion that is mapped to at least one logical sector address from the long-term storage medium, said at least one logical sector address selected for use by an operating system to access said mapped portion in said non-volatile memory;

defining, in said non-volatile memory, a cache portion that is not under direct control of said operating system and is different than said mapped portion which is under exclusive and direct control of said operating system, said data stored in a first portion of said non-volatile memory, wherein said first portion is said mapped portion or said cache portion

determining that data written to non-volatile memory is no longer required; and

based on said determination, restricting the data so that there is no flushing of any portion of the data to the long-term storage medium.

2. The method of claim 1, further comprising overwriting the data in the non-volatile memory.

3. The method of claim 1, further comprising:

establishing a list of logical sector addresses to ignore.

4. The method of claim 3, wherein the determination that the data written to the non-volatile memory is no longer required is based on the list of logical sector addresses.

5. The method of claim 1, wherein the data comprises temporary files.

6. The method of claim 5, wherein the temporary files and metadata of the temporary files are initially created in the non-volatile memory.

7. The method of claim 1, further comprising:

storing file data in said mapped portion as a result of said file being a temporary file, said data comprising said file data.

8. The method of claim 7, further comprising:

storing metadata related to said file data in said mapped portion based on said file being a temporary file, and said data comprising said metadata.

9. A computer system comprising:

a non-volatile memory;

a long-term storage medium; and

a processor configured with an operating system or application configured to;

define, in said non-volatile memory, a mapped portion that is mapped to at least one logical sector address from the long-term storage medium, said at least one logical sector address selected for use by an operating system to access said mapped portion in said non-volatile memory;

define, in said non-volatile memory, a cache portion that is not under direct control of said operating system and is different than said mapped portion which is under exclusive and direct control of said operating system, said data stored in a first portion of said non-volatile memory, wherein said first portion is said mapped portion or said cache portion; and

communicate, for a first data written to the non-volatile memory, a restriction which includes no flushing of any of the first data to the long-term storage medium.

10. The computer system of claim 9, the operating system or application further configured to:

anticipate that a size of a second data of an application is relatively large for the non-volatile memory; and

based on said anticipation, write or read the second data to or from the long-term storage medium, circumventing writing or reading of the second data to or from the non-volatile memory.

11. The computer system of claim 9, the operating system or application further configured to overwrite the first data of the non-volatile memory.

12. The computer system of claim 9, the operating system or application further configured to establish a listing of logical sector addresses for the restriction.

13. The computer system of claim 9, the operating system or application further configured to establish that the first data written to the non-volatile memory should have said restriction based on the list of logical sector addresses.

14. The computer system of claim 9, wherein the first data comprises a file as a result of said file being a temporary file.

15. The computer system of claim 14, wherein the temporary file and metadata of the temporary file is initially created in the non-volatile memory.

16. A computer readable storage medium comprising computer executable instructions that when executed by a computing device cause said computing device to perform the instructions comprising:

defining, in said non-volatile memory, a mapped portion that is mapped to at least one logical sector address from the long-term storage medium, said at least one logical sector address selected for use by an operating system to access said mapped portion in said non-volatile memory;

defining, in said non-volatile memory, a cache portion that is not under direct control of said operating system and is different than said mapped portion which is under exclusive and direct control of said operating system, said data stored in a first portion of said non-volatile memory, wherein said first portion is said mapped portion or said cache portion

determining that data written to non-volatile memory is no longer required; and

based on said determination, restricting the data so that there is no flushing of any portion of the data to the long-term storage medium.

17. The computer readable storage medium of claim 16, further instructions comprising overwriting the data in the non-volatile memory.

18. The computer readable storage medium of claim 16, further instructions comprising establishing a list of logical sector addresses to ignore.

19. The computer readable storage medium of claim 18, wherein the determination that the data written to the non-volatile memory is no longer required is based on the list of logical sector addresses.

20. The computer readable storage medium of claim 16, wherein the data comprises temporary files.

21. The computer readable storage medium of claim 20, wherein the temporary files and metadata of the temporary files are initially created in the non-volatile memory.

22. The computer readable storage medium of claim 16, further instructions comprising storing file data in said mapped portion as a result of said file being a temporary file, said data comprising said file data.

23. The computer readable storage medium of claim 22, further instructions comprising storing metadata related to said file data in said mapped portion based on said file being a temporary file, and said data comprising said metadata.