SYSTEM AND METHOD FOR MANAGING DATA IN A MEMORY DEVICE

• US 20160179371A1
• Filed: 12/17/2014
• Published: 06/23/2016
• Est. Priority Date: 12/17/2014
• Status: Active Grant

• Current Assignee: SanDisk Technologies LLC (Western Digital Corporation)
• Original Assignee: Sandisk Technologies Incorporated (Western Digital Corporation)
• Inventors: Sinclair, Alan Welsh
• Granted Patent: US 9,690,491 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 11/1072 in multilevel memories
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 2212/7201 Logical to physical mapping or translation of blocks or pages
• CPC Class Codes: G06F 3/061 Improving I/O performance
• CPC Class Codes: G06F 3/064 Management of blocks
• CPC Class Codes: G06F 3/0688 Non-volatile semiconductor memory arrays
• CPC Class Codes: G11C 29/028 with adaption or trimming of parameters

Abstract

A non-volatile memory system may have a group of non-volatile memory cells having a plurality of predetermined portions, where each predetermined portion is associated with an open host write block of a different host data type than each other predetermined portion. A host data router directs received data from a host to an appropriate predetermined portion based on a determined data type. A maintenance data router, based on predetermined minimum capacity overprovisioning targets for each predetermined portion, operates to adjust an amount of overprovisioning of physical capacity among the plurality of predetermined portions to reduce write amplification and increase performance in predetermined portions having data with a higher probability of host update. The method may include selecting a particular predetermined portion and a particular block within the selected predetermined portion on which to perform a maintenance operation to achieve the desired capacity overprovisioning.

Claims

1. A method for managing maintenance procedures in an independently managed non-volatile memory set of a non-volatile memory, the method comprising:

receiving data associated with a data write command from a host;

identifying which of a plurality of data types the received data is associated with based on data type information received from the host;

storing the received data having the identified data type in a predetermined portion of the independently managed non-volatile memory set, the independently managed non-volatile memory set having a group of non-volatile memory cells of a same storage density, wherein the group of non-volatile memory cells comprises a plurality of predetermined portions, each of the predetermined portions having an open host write block associated with only a respective one of a plurality of different host data types;

detecting a maintenance operation trigger;

in response to detecting the maintenance operation trigger, selecting one of the plurality of predetermined portions in which to execute a maintenance operation based on a respective physical capacity overprovisioning criteria associated with each of the plurality of predetermined portions;

executing the maintenance operation on a block of the selected predetermined portion to adjust physical capacity overprovisioning of the selected predetermined portion to meet the physical capacity overprovisioning criteria for the selected predetermined portion.

2. The method of claim 1, wherein selecting one of the plurality of predetermined portions comprises selecting the predetermined portion having a highest ratio of actual valid data above a predetermined maximum amount of valid data for that predetermined portion.

3. The method of claim 2, wherein executing the maintenance operation comprises selecting a block in the selected predetermined portion, the selected block having an amount of valid data necessary to reduce a ratio of actual valid data relative to a maximum amount of valid data for the selected predetermined portion.

4. The method of claim 3, wherein executing the maintenance operation further comprises moving valid data from the selected block from the selected predetermined portion to a different predetermined portion and moving a block freed by the maintenance operation from the selected predetermined portion to a free block pool.

5. The method of claim 1, wherein selecting the predetermined portion comprises, when no predetermined portion has an amount of valid data greater than a predetermined maximum amount of valid data for that predetermined portion, selecting the predetermined portion having a lowest ratio of actual valid data to the predetermined maximum amount of valid data for that predetermined portion.

6. The method of claim 5, wherein executing the maintenance operation comprises selecting a block in the selected predetermined portion, the selected block having a least amount of valid data of blocks in the selected predetermined portion.

7. The method of claim 6, wherein executing the maintenance operation further comprises moving valid data from the selected block from the selected predetermined portion to a different block in the selected predetermined portion and moving a block freed by the maintenance operation from the selected predetermined portion to a free block pool.

8. A non-volatile memory system comprising:

an independently managed non-volatile memory set having a plurality of predetermined portions in a layer of the independently managed non-volatile memory set, where the layer comprises blocks of memory cells having a same bit per cell storage capacity and each predetermined portion is defined by an open host write block exclusively associated with a data type that differs from each other of the plurality of predetermined portions;

a host data router in communication with the plurality of predetermined portions and configured to route data received from a host to one of the plurality of predetermined portions based on the data type of the data received from the host; and

a maintenance data router in communication with the plurality of predetermined portions, the maintenance data router configured to adjust a current physical capacity overprovisioning in at least one predetermined portion in response to detecting a maintenance trigger event, wherein current physical capacity overprovisioning comprises a relation of a current physical data storage capacity associated with a particular predetermined portion to a current amount of valid data associated with the particular predetermined portion.

9. The non-volatile memory system of claim 8, wherein the data type for each predetermined portion identifies data having a frequency of expected data update.

10. The non-volatile memory system of claim 8, wherein the plurality of predetermined portions comprises a first predetermined portion associated with data having a high expected update frequency and a second predetermined portion associated with data having a low expected update frequency.

11. The non-volatile memory system of claim 8, wherein the host data router is configured to recognize the data type of received data from a host data tag received from the host.

12. The non-volatile memory system of claim 8, where the non-volatile memory system is embedded in the host.

13. The non-volatile memory system of claim 8, where the non-volatile memory system is removably connectable to the host.

14. The non-volatile memory system of claim 8, wherein the maintenance data router is configured to, in response to detecting a maintenance operation trigger, identify a predetermined portion having a highest ratio of actual valid data above a predetermined maximum amount of valid data for the identified predetermined portion, and to move data from the identified predetermined portion to a different predetermined portion.

15. The non-volatile memory system of claim 14, wherein the maintenance data router is further configured to select a block, in the identified predetermined portion, having an amount of valid data necessary to reduce a ratio of actual valid data relative to a maximum amount of valid data for the identified predetermined portion.

16. The non-volatile memory system of claim 15, wherein the maintenance data router is further configured to move valid data from the selected block of the identified predetermined portion to a different predetermined portion and move a block freed from the identified predetermined portion to a free block pool.

17. The non-volatile memory system of claim 8, wherein the maintenance data router is configured to adjust the overprovisioning by, when no predetermined portion has an amount of valid data greater than a predetermined maximum amount of valid data for that predetermined portion, selecting for a maintenance operation a predetermined portion having a lowest ratio of actual valid data to the predetermined maximum amount of valid data for that predetermined portion.

18. The non-volatile memory system of claim 17, wherein the maintenance data router is configured to select a block in the selected predetermined portion having a least amount of valid data of blocks in the selected predetermined portion.

19. The non-volatile memory system of claim 18, wherein the maintenance data router is further configured to moving valid data from the selected block of the selected predetermined portion to a different block in the selected predetermined portion and to move a block freed by the maintenance operation from the selected predetermined portion to a free block pool.

20. A non-volatile memory system comprising:

an independently managed non-volatile memory set having a plurality of predetermined portions in a single group of the non-volatile memory, where the single group comprises blocks of memory cells having a same bit per cell storage capacity, and wherein each predetermined portion includes an open host write block exclusively associated with a data type that differs from a data type of an open host write block of each other of the plurality of predetermined portions;

a host data router configured to identify a data type of host data and route host data having the identified data type to a host data subportion in one of the plurality of predetermined portions having an open host write block exclusively associated with the identified data type; and

a maintenance data router having a first mode wherein the maintenance data router is configured to move data from a host data subportion to a maintenance data subportion in a same predetermined portion, and a second mode, wherein the maintenance data router is configured to move data from the maintenance data subportion in a first predetermined portion to a maintenance data subportion in a second predetermined portion associated with a data type of data having a lower probability of update.