Techniques for directed data migration

• US 10,552,085 B1
• Filed: 07/15/2016
• Issued: 02/04/2020
• Est. Priority Date: 09/09/2014
• Status: Active Grant

• Current Assignee: Radian Memory Systems, LLC
• Original Assignee: Radian Memory Systems, Inc.
• Inventors: Chen, Alan, Robertson, Craig, Lercari, Robert, Kuzmin, Andrey V.
• Primary Examiner(s): Yi, David
• Assistant Examiner(s): Ahmed, Zubair
• Application Number:
  US15/211,939
• Time in Patent Office: 1,299 Days
• 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 3/0647 Migration mechanisms
• CPC Class Codes: G06F 3/0655 Vertical data movement, i.e. input-output transfer; data movement between one or more hosts and one or more storage devices
• CPC Class Codes: G06F 3/0679 Non-volatile semiconductor memory device, e.g. flash memory, one time programmable memory [OTP]
• CPC Class Codes: G06F 3/0685 Hybrid storage combining heterogeneous device types, e.g. hierarchical storage, hybrid arrays

Abstract

A host stores “context” metadata for logical block addresses (LBAs) in a manner tied to physical location. Notwithstanding log-structured or copy on write processes, the host is then provided with immediate context when the host is called upon to assist a memory controller with data identified by physical location, for example, for memory reconfiguration, garbage collection, wear leveling or other processes. The metadata for example can provide the host with insight as to which data may be moved to enhance performance optimization and where that data can be placed. In one embodiment, the host writes back one or more references that span multiple layers of indirection in concert with write of the underlying data; in another embodiment, the context can point to other metadata.

Claims

1. A memory controller integrated circuit to control flash memory, the flash memory having a plurality of storage locations disposed within structural elements of the flash memory, the memory controller integrated circuit comprising:

a host interface to receive write commands, data to be written into the nonvolatile memory in association with respective ones of the write commands, and back reference information associated with the respective data, wherein each one of the write commands is accompanied by a respective address, the respective address to determine one of the structural elements to serve as destination for respective data;

circuitry to store the back reference information in a manner indexed to at least one of a portion of the respective address or the destination in which the respective data is stored;

a memory interface to transmit data to the flash memory for storage therein in response to the write commands;

circuitry to transfer move data from a storage location in a given one of the structural elements in the flash memory to a storage destination outside of the given one in association with a flash memory maintenance operation;

circuitry to retrieve back reference information respective to the move data and to transmit the retrieved back reference information to a host;

wherein the memory controller integrated circuit is not to transfer to the host the move data in association with the transfer to the storage destination; and

wherein the retrieved back reference information transmitted to the host comprises data which identifies to the host at least one level of indirection used by the host to identify the respective address given a base reference used by the host to access the respective data corresponding to the back reference information.

2. The memory controller integrated circuit of claim 1, wherein:

the memory controller integrated circuit further comprises onboard storage to store the back reference information, in a manner indexed to a logical block address associated with the respective data.

3. The memory controller integrated circuit of claim 1, wherein:

the memory controller is to maintain the back reference information in a memory location external to said memory controller integrated circuit.

4. The memory controller integrated circuit of claim 1, wherein:

the memory controller integrated circuit further comprises circuitry to transmit to the host information identifying a need for the transfer of the move data;

the circuitry to transfer the move data is responsive to an explicit command from the host to transfer the move data, such that an order of transfer of the move data relative to other host commands is at least partially dependent on a host order of interleaving of the explicit command relative the other host commands; and

the circuitry to transfer the move data is not to transfer other data stored in the flash memory which is not the subject of an explicit command specific to the other data.

5. The memory controller integrated circuit of claim 1, wherein:

the circuitry to transfer the move data is responsive to an explicit command from the host to transfer the move data, such an order of the transfer of the move data relative to other host commands is at least partially dependent on host order of interleaving of the explicit command relative to the other host commands;

the explicit command is to specify an address of the storage destination, the circuitry to transfer the move data to the address specified for the storage destination in response to the address specified by the explicit command; and

the circuitry to transfer the move data is not to transfer other data stored in the flash memory which is not the subject of an explicit command specific to the other data.

6. The memory controller integrated circuit of claim 1, wherein the storage destination outside of the given one is a storage location in another one of the structural elements.

7. The memory controller integrated circuit of claim 6, wherein the structural elements each comprise at least one discrete flash memory die, each of the discrete flash memory dies to be controlled by the memory controller integrated circuit.

8. The memory controller integrated circuit of claim 6, wherein the structural elements are each respective memory channels, each of the respective memory channels to be controlled by the memory controller integrated circuit.

9. The memory controller integrated circuit of claim 6, wherein the structural elements are each respective virtual block devices, each of the respective virtual block devices to be controlled by the memory controller integrated circuit, each of the respective virtual block devices comprising at least one discrete flash memory die.

10. The memory controller integrated circuit of claim 1, wherein the flash memory comprises a first storage drive to be controlled by said memory controller integrated circuit, and wherein said storage destination comprises a storage location in another storage drive that is not to be controlled by said memory controller integrated circuit.

11. The memory controller integrated circuit of claim 1, wherein:

the memory controller integrated circuit further comprises circuitry to translate the respective address that accompanies each one of the write commands from a logical address to a physical address within the flash memory, the physical address corresponding to one of the storage locations;

the storage destination outside of the given one is a storage location in another one of the structural elements; and

the memory controller integrated circuit comprises circuitry to explicitly transmit to the host, together with the retrieved back reference information, a physical address corresponding to the given one of the structural elements as well as a physical address corresponding to the storage destination.

12. The memory controller integrated circuit of claim 1, wherein:

the storage destination outside of the given one is a storage location in another one of the structural elements; and

the memory controller integrated circuit further comprises circuitry to move storage of the retrieved back reference information from a first indexed location, corresponding to the storage location in the given one of the structural elements, to a second indexed location, corresponding to the storage location in the other one of the structural elements.

13. The memory controller integrated circuit of claim 1, wherein:

each respective address comprises bits; and

a set of the bits for each respective address is to directly map the data to a subset of the structural elements of the flash memory.

14. The memory controller integrated circuit of claim 1, wherein:

each one of the structural elements is characterized by associated performance characteristics comprising a time to program a page of memory cells in the nonvolatile memory, and a time to erase memory cells in the flash memory; and

the memory controller integrated circuit further comprises circuitry to control the execution of read and write commands on an independent basis for respective ones of the structural elements of the flash memory, in a manner such that the scheduling of performance of a command in one of the respective ones is unconstrained by the performance characteristics associated with another of the respective ones.

15. The memory controller integrated circuit of claim 14, wherein the respective ones comprise respective flash memory dies controlled by said memory controller integrated circuit.

16. A memory controller integrated circuit to control flash memory, the flash memory having a plurality of storage locations disposed within structural elements of the flash memory, the memory controller integrated circuit comprising:

a host interface to receive write commands, data to be written into the nonvolatile memory in association with respective ones of the write commands, and back reference information associated with respective data, wherein each one of the write commands is accompanied by a respective address, the respective address to determine one of the structural elements to serve as a destination for the data associated with the one of the write commands;

circuitry to store the back reference information in a manner indexed to at least one of a portion of the respective address or the destination in which the respective data is stored;

a memory interface to transmit data to the flash memory for storage therein in response to the write commands;

circuitry to transfer move data from a storage location in a given one of the structural elements in the flash memory to a storage destination outside of the given one in association with a flash memory maintenance operation; and

circuitry to retrieve back reference information respective to the move data and to transmit the retrieved back reference information to a host;

wherein

the memory controller integrated circuit is not to transfer the move data to the host in association with the transfer of the move data to the storage destination,

the storage destination outside of the given one is a storage location in another one of the structural elements, and

the retrieved back reference information transmitted to the host comprises data which identifies to the host at least one level of indirection used by the host to identify the respective address given a base reference used by the host to access the respective data corresponding to the back reference information.

17. The memory controller integrated circuit of claim 16, wherein:

the memory controller integrated circuit further comprises onboard storage to store the back reference information.

18. The memory controller integrated circuit of claim 16, wherein:

the memory controller is to maintain the back reference information in a memory location external to said flash memory controller integrated circuit.

19. The memory controller integrated circuit of claim 16, wherein:

the memory controller integrated circuit further comprises circuitry to transmit to the host information identifying a need for the transfer of the move data;

the circuitry to transfer the move data is responsive to an explicit command from the host to transfer the move data, such that an order of the transfer of the move data relative to other host commands is at least partially dependent on a host order of interleaving of the explicit command relative to the other host commands; and

the circuitry to transfer the move data is not to transfer other data stored in the flash memory which is not the subject of an explicit command specific to the other data.

20. The memory controller integrated circuit of claim 16, wherein:

the circuitry to transfer the move data is responsive to an explicit command from the host to transfer the move data, such an order of the transfer of the move data relative to other host commands is dependent on a host order of interleaving of the explicit command relative to the other host commands;

the explicit command is to specify an address of the storage destination, the circuitry to transfer the move data to the address specified for the storage destination in response to the address specified by the explicit command; and

the circuitry to transfer the move data is not to transfer other data stored in the flash memory which is not the subject of an explicit command specific to the other data.

21. The memory controller integrated circuit of claim 16, wherein the structural elements each comprise at least one discrete flash memory die, each of the discrete flash memory dies to be controlled by the memory controller integrated circuit.

22. A memory controller integrated circuit to control flash memory, the flash memory having a plurality of storage locations disposed within structural elements of the flash memory, the memory controller integrated circuit comprising:

a host interface to receive write commands, data to be written into the nonvolatile memory in association with respective ones of the write commands, and back reference information associated with respective data, wherein each one of the write commands is accompanied by a respective address, the respective address to determine one of the structural elements to serve as a destination for the data associated with the one of the write commands;

circuitry to store the back reference information in a manner indexed to at least one of a portion of the respective address or the destination in which the respective data is stored;

a memory interface to transmit data to the flash memory for storage therein in response to the write commands;

circuitry to transfer move data from a storage location in a given one of the structural elements in the flash memory to a storage destination outside of the given one in association with a flash memory maintenance operation; and

circuitry to retrieve back reference information respective to the move data and to transmit the retrieved back reference information to a host;

wherein

the memory controller integrated circuit is not to transfer the move data to the host, in association with the transfer to the storage destination,

the flash memory comprises a first storage drive to be controlled by said memory controller integrated circuit,

said storage destination comprises a storage location in another storage drive that is not to be controlled by said memory controller integrated circuit, and

the back reference information comprises information sufficient to identify a forward reference identification of the respective data, said forward reference identification adapted to span multiple layers of indirection, relative to a file system of the host, and

the retrieved back reference information transmitted to the host comprises data which identifies to the host at least one level of indirection used by the host to identify the respective address given a base reference used by the host to access the respective data corresponding to the back reference information.

23. The memory controller integrated circuit of claim 22, wherein:

the circuitry to transfer the move data is responsive to an explicit command from the host to transfer the move data, such an order of the transfer of the move data relative to other host commands is dependent on a host order of interleaving of the explicit command relative to the other host commands;

the explicit command is to specify an address of the storage destination, the circuitry to transfer the move data to the address specified for the storage destination in response to the address specified by the explicit command; and

the circuitry to transfer the move data is not to transfer other data stored in the flash memory which is not the subject of an explicit command specific to the other data.