Flash interface for processing datasets

• US 10,037,164 B1
• Filed: 06/29/2016
• Issued: 07/31/2018
• Est. Priority Date: 06/29/2016
• Status: Active Grant

• Current Assignee: Emc IP Holding Company LLC (Dell Technologies Inc.)
• Original Assignee: Emc IP Holding Company LLC (Dell Technologies Inc.)
• Inventors: Wallace, Grant R., Shilane, Philip N.
• Primary Examiner(s): Chappell, Daniel C
• Application Number:
  US15/196,110
• Time in Patent Office: 762 Days
• CPC Class Codes: G06F 12/0802 Addressing of a memory level in which the access to the desired data or data block requires associative addressing means, e.g. caches
• CPC Class Codes: G06F 2212/1036 Life time enhancement
• CPC Class Codes: G06F 2212/222 Non-volatile memory
• CPC Class Codes: G06F 2212/7202 Allocation control and policies
• CPC Class Codes: G06F 3/061 Improving I/O performance
• CPC Class Codes: G06F 3/0616 in relation to life time, e.g. increasing Mean Time Between Failures [MTBF]
• CPC Class Codes: G06F 3/064 Management of blocks
• CPC Class Codes: G06F 3/0679 Non-volatile semiconductor memory device, e.g. flash memory, one time programmable memory [OTP]
• CPC Class Codes: G11C 16/10 Programming or data input circuits
• CPC Class Codes: G11C 16/16 for erasing blocks, e.g. arrays, words, groups
• CPC Class Codes: G11C 16/349 Arrangements for evaluating degradation, retention or wearout, e.g. by counting erase cycles

Abstract

Systems and methods for managing content in a flash memory. Content or data in a flash memory is overwritten when the write operation only requires bits to be set. This improves performance of the flash and extends the life of the flash memory.

Claims

1. In a system that includes a flash memory, a method for overwriting a portion of the flash memory, the method comprising:

receiving a write request at a flash memory from a client that includes a write block, wherein the flash memory includes a controller and an external interface, wherein the controller performs write requests that are internal to the system and wherein the external interface allows the client to make a call to the flash memory, wherein the client specifies how to perform the write request in the flash memory via the call to the flash memory received through the external interface,

comparing the write block with a target block in the flash memory; and

overwriting the target block when the comparison indicates that only sets are needed to write the write block to the target block.

2. The method of claim 1, further comprising writing the write block to a new location in the flash memory when unsets are required to write the write block to the target block.

3. The method of claim 1, further comprising receiving a location in the write request.

4. The method of claim 1, further comprising reading the target block internally after receiving the write request.

5. The method of claim 4, further comprising locking the target block with a lock when reading the target block, comparing the write block with the target block, and overwriting the target block.

6. The method of claim 5, further comprising reading the target block before overwriting the target block.

7. The method of claim 6, further comprising unlocking the target block after overwriting the target block.

18. The flash memory of claim 1, wherein a set includes setting a 0 to a 1 and wherein an unset includes setting a 1 to a 0, wherein unsets are performed on entire erasure units.

8. In a system that includes a flash memory, a method for writing to a flash memory, the method comprising:

receiving a call from a client at an external interface of the flash memory, wherein the call includes a data block and an address and wherein the call from the client specifies an operation for performing a write to the flash memory;

specifying how to perform the operation via the call from the client to the flash memory received through the external interface;

overwriting a target block at the address with the data block when only sets are required to write the data block to a location of the target block using the specified operation; and

writing the data block to a new location when an unset is required to write the data block to the location of the target block.

9. The method of claim 8, wherein the call comprises a logical OR and the external interface comprises an application programming interface.

10. The method of claim 8, wherein the call comprises a compare and swap and the external interface comprises an application programming interface.

11. The method of claim 9, wherein the logical OR modifies the target block to be the logical OR of its contents with the contents of the data block.

12. The method of claim 10, wherein the call further includes a previous version of the target block and the data block, which is a new version of the target block.

13. The method of claim 12, wherein the new version includes more set bits than the target block.

14. The method of claim 12, further comprising comparing the previous version with the target block and overwriting the target block with the data block when the previous version matches the target block.

15. The method of claim 14, wherein the data block is not written to the target block when the previous version does not match the target block.

16. The method of claim 14, wherein the call locks the target block while the call is executed.

17. In a system that includes a flash memory comprising:

a memory configured to store data segments, wherein the memory is written in pages and erased based on erasure units, wherein each erasure unit included multiple pages;

an external interface that is configured to receive calls from a client that cause the target block to be overwritten, wherein the client specifies the a call when accessing the external interface and wherein the client specifies how to overwrite the target block in the flash memory via the calls from the client received through the external interface; and

a controller that includes a processor, the controller configured to execute logic in response to the calls from the client when writing a data block to a location in the memory in which is stored a target block, wherein the controller overwrites the target block with the data block when only sets are required and wherein the controller writes the data block to a new location when an unset is required and wherein the controller performs writes to the memory that are from the system and that are received from the external interface.

19. The flash memory of claim 17, wherein the external interface allows the client to issue a logical OR call that modifies contents of the target block at the location to be the logical OR of the contents of the data block, wherein the logical OR sets 0s in the target block to 1s based on the contents of the data block.

20. The flash memory of claim 17, wherein the external interface allows the client to issue a compare and swap call that includes a previous version of the target block and the data block, which is a new version of the target block, wherein the target block is combined with the data block by logical-OR when the previous version of the target block matches the target block at the location.