Flash interface for processing datasets

• US 10,318,201 B2
• Filed: 07/31/2018
• Issued: 06/11/2019
• 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:
  US16/049,891
• Publication Number:
  US 20180335948A1
• Time in Patent Office: 315 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 writing data to the flash memory, the method comprising:

receiving a call from a client to write data to a location in the flash memory, wherein the client specifies in the call how to write the data;

determining whether the location can be overwritten;

overwriting the location when the location can be overwritten, wherein the location is overwritten in a manner specified in the call; and

marking the location for erasure when the location cannot be overwritten.

2. The method of claim 1, further comprising writing the write block to a new location in the flash memory when the location is marked for erasure.

3. The method of claim 1, further comprising receiving the call through an external interface provided by the flash memory, wherein a controller associated with the flash memory performs the call.

4. The method of claim 1, further comprising comparing the data with target data stored in the flash memory and overwriting the location only when sets of bits are needed to write the data to the location storing the target data in the flash memory.

5. The method of claim 4, further comprising locking the target data with a lock when reading the target data, comparing the write data with the target data, and overwriting the target data with the write data, and then unlocking the write data stored in the flash memory.

6. The method of claim 1, wherein the call is a compare and swap call or a logical OR call.

7. The method of claim 1, wherein the write data is part of a data structure and the data structure is one of a bloom filter, a linked list, a hash table, a locking data structure, a tree, or a graph.

8. A method for writing to a flash memory, the method comprising:

receiving a call from a client at the flash memory to perform a write operation, wherein the call includes a data block;

determining, by a controller of the flash memory, a manner in which to perform the write operation in the flash memory;

overwriting a target block at a location in the flash memory associated with the data block using the determined manner when only sets are required to write the data block to the location of the target block;

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; and

marking the location in the flash memory of the target block for erasure when the location cannot be overwritten.

9. The method of claim 8, further comprising determining to perform the write operation using a logical OR a compare and swap operation.

10. The method of claim 8, further comprising receiving the call at an external interface.

11. The method of claim 8, further comprising reading the target block and comparing the target block with the data block to determine whether the target block can be overwritten using only sets.

12. The method of claim 8, further comprising determining that unsets are required to write the data block to the location of the target block.

13. The method of claim 8, further comprising locking at least the target block such that another client does not interfere with the write operation or the target block during performance of the write operation.

14. The method of claim 8, further comprising allowing the client to specify how the call is performed.

15. The method of claim 8, wherein the data block is associated with a data structure, the data structure comprising a bloom filter, a linked list, a hash table, a locking data structure, a tree, or a graph.

16. A device comprising:

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

a controller that controls the flash memory and that includes a processor;

wherein the controller is configured to;

write data associated with a write operation to a target location in the flash memory that stores target data and wherein the controller is configured to determine how to write the data to the flash memory,

overwrite the target data with the data when only sets are required to change the target data to the data and wherein the controller writes the data to a new location when an unset is required to be made to the target data, and

mark the target data for erasure when the unset is required and the target data cannot be overwritten with the data of the write operation.

17. The device of claim 16, wherein the flash memory includes an external interface that allows a manner in which the target data is overwritten to be specified by a client.

18. The device 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.

19. The device 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.

20. The device of claim 16, wherein the controller is configured to determine whether the target data the location of can be overwritten before overwriting the target data, wherein the controller is configured to prevent other clients from interfering with the write operation.