STORAGE CLASS MEMORY STATUS

• US 20190266078A1
• Filed: 02/28/2018
• Published: 08/29/2019
• Est. Priority Date: 02/28/2018
• Status: Active Grant

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Porzio, Luca, Mirichigni, Graziano, Caraccio, Danilo
• Granted Patent: US 10,642,728 B2
• Time in Patent Office: Days
• CPC Class Codes: G06F 12/0238 Memory management in non-volatile memory, e.g. resistive RAM or ferroelectric memory
• CPC Class Codes: G06F 12/1009 using page tables, e.g. page table structures
• 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 3/0673 Single storage device
• CPC Class Codes: G06F 3/0679 Non-volatile semiconductor memory device, e.g. flash memory, one time programmable memory [OTP]
• CPC Class Codes: G11C 29/52 Protection of memory contents; Detection of errors in memory contents

Abstract

Devices and techniques for storage class memory status are disclosed herein. A storage portion characteristics data structure is maintained. Here, the data structure includes an array of elements—where each element is sized to contain a reference to a storage portion in a storage class memory storage device, a first pointer to a first element in the array of elements, a second pointer to a second element in the array of elements, and a third pointer to a third element in the array of elements. The data structure includes a direction of pointer motion in which the second pointer precedes the third pointer and the first pointer precedes the second pointer with respect to the direction of pointer motion. A write request is performed to a storage portion reference retrieved from the first element. The first pointer is then advanced.

Claims

1. A device for storage class memory status, the device comprising:

a storage class memory array; and

a controller including processing circuitry to;

maintain a storage portion characteristics data structure, the data structure comprising;

an array of elements, each element sized to contain a reference to a storage portion in the storage class memory array;

a first pointer to a first element in the array of elements;

a second pointer to a second element in the array of elements; and

a third pointer to a third element in the array of elements, the data structure including a direction of pointer motion, the second pointer preceding the third pointer and the first pointer preceding the second pointer with respect to the direction of pointer motion;

receive a write request;

retrieve a storage portion reference from the first element;

perform the write request to the storage portion reference; and

advance the first pointer.

2. The device of claim 1, wherein the processing circuitry is to:

retrieve an original storage portion reference for the write request from a translation table, the write request updating a previously stored value on the original storage portion;

write the original storage portion reference to the third element; and

advance the third pointer.

3. The device of claim 1, wherein the processing circuitry is to:

perform maintenance upon a storage portion with a reference stored in the second element; and

advance the second pointer in response to the maintenance.

4. The device of claim 1, wherein elements in the array of elements between the first pointer and the second pointer, including the first pointer and not the second pointer, include storage portion references to storage portions in which data may be written.

5. The device of claim 1, wherein elements in the array of elements between the second pointer and the third pointer, including the second pointer and not the third pointer, include storage portion references to storage portions that are invalid.

6. The device of claim 1, wherein the array of elements is a circular array.

7. The device of claim 1, wherein the first pointer, the second pointer, and the third pointer are stored in a reserved area of the storage class memory array that is distinct from a logical-to-physical translation area and a data area of the storage class memory array.

8. The device of claim 7, wherein the entire data structure is stored in the reserved area.

9. A method for storage class memory status, the method comprising:

maintaining a storage portion characteristics data structure, the data structure comprising;

an array of elements, each element sized to contain a reference to a storage portion in a storage class memory storage device;

a first pointer to a first element in the array of elements;

a second pointer to a second element in the array of elements; and

a third pointer to a third element in the array of elements, the data structure including a direction of pointer motion, the second pointer preceding the third pointer and the first pointer preceding the second pointer with respect to the direction of pointer motion;

receiving a write request;

retrieving a storage portion reference from the first element;

performing the write request to the storage portion reference; and

advancing the first pointer.

10. The method of claim 9, comprising:

retrieving an original storage portion reference for the write request from a translation table, the write request updating a previously stored value on the original storage portion;

writing the original storage portion reference to the third element; and

advancing the third pointer.

11. The method of claim 9, comprising:

performing maintenance upon a storage portion with a reference stored in the second element; and

advancing the second pointer in response to the maintenance.

12. The method of claim 9, wherein elements in the array of elements between the first pointer and the second pointer, including the first pointer and not the second pointer, include storage portion references to storage portions in which data may be written.

13. The method of claim 9, wherein elements in the array of elements between the second pointer and the third pointer, including the second pointer and not the third pointer, include storage portion references to storage portions that are invalid.

14. The method of claim 9, wherein the array of elements is a circular array.

15. The method of claim 9, wherein the first pointer, the second pointer, and the third pointer are stored in a reserved area of the storage class memory storage device that is distinct from a logical-to-physical translation area and a data area.

16. The method of claim 15, wherein the entire data structure is stored in the reserved area.

17. At least one computer readable medium including instructions that, when executed by processing circuitry, cause the processing circuitry to perform operations comprising:

maintaining a storage portion characteristics data structure, the data structure comprising;

an array of elements, each element sized to contain a reference to a storage portion in a storage class memory storage device;

a first pointer to a first element in the array of elements;

a second pointer to a second element in the array of elements; and

a third pointer to a third element in the array of elements, the data structure including a direction of pointer motion, the second pointer preceding the third pointer and the first pointer preceding the second pointer with respect to the direction of pointer motion;

receiving a write request;

retrieving a storage portion reference from the first element;

performing the write request to the storage portion reference; and

advancing the first pointer.

18. The computer readable medium of claim 17, wherein the operations further comprise:

retrieving an original storage portion reference for the write request from a translation table, the write request updating a previously stored value on the original storage portion;

writing the original storage portion reference to the third element; and

advancing the third pointer.

19. The computer readable medium of claim 17, wherein the operations further comprise:

performing maintenance upon a storage portion with a reference stored in the second element; and

advancing the second pointer in response to the maintenance.

20. The computer readable medium of claim 17, wherein elements in the array of elements between the first pointer and the second pointer, including the first pointer and not the second pointer, include storage portion references to storage portions in which data may be written.

21. The computer readable medium of claim 17, wherein elements in the array of elements between the second pointer and the third pointer, including the second pointer and not the third pointer, include storage portion references to storage portions that are invalid.

22. The computer readable medium of claim 17, wherein the array of elements is a circular array.

23. The computer readable medium of claim 17, wherein the first pointer, the second pointer, and the third pointer are stored in a reserved area of the storage class memory storage device that is distinct from a logical-to-physical translation area and a data area.

24. The computer readable medium of claim 23, wherein the entire data structure is stored in the reserved area.