Detecting error count deviations for non-volatile memory blocks for advanced non-volatile memory block management

• US 9,563,373 B2
• Filed: 10/21/2014
• Issued: 02/07/2017
• Est. Priority Date: 10/21/2014
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Camp, Charles J., Fisher, Timothy J., Fry, Aaron D., Ioannou, Nikolas, Pletka, Roman, Tomic, Sasa
• Primary Examiner(s): Blair, April Y
• Assistant Examiner(s): GANDHI, DIPAKKUMAR B
• Application Number:
  US14/520,276
• Publication Number:
  US 20160110124A1
• Time in Patent Office: 840 Days
• US Class Current: 1/1
• CPC Class Codes: G06F 11/073 in a memory management context, e.g. virtual memory or cache management memory management G06F12/00; testing of static memory units G11C29/00
• CPC Class Codes: G06F 11/076 by exceeding a count or rate limit, e.g. word- or bit count limit
• CPC Class Codes: G06F 11/0793 Remedial or corrective actions recovery from an exception in an instruction pipeline G06F9/3861; by retry G06F11/1402; for recovering from a failure of a protocol instance or entity H04L69/40
• CPC Class Codes: G06F 11/1072 in multilevel memories
• CPC Class Codes: G06F 3/0619 in relation to data integrity, e.g. data losses, bit errors
• CPC Class Codes: G06F 3/0647 Migration mechanisms
• CPC Class Codes: G06F 3/0653 Monitoring storage devices or systems
• CPC Class Codes: G06F 3/0688 Non-volatile semiconductor memory arrays
• CPC Class Codes: G11C 29/52 Protection of memory contents; Detection of errors in memory contents

Abstract

Non-volatile memory block management. A method according to one embodiment includes determining a block health of at least some non-volatile memory blocks of a plurality of non-volatile memory blocks that are configured to store data. An error count margin threshold is calculated for each of the at least some non-volatile memory blocks. A determination is made as to whether the error count margin threshold of any of the at least some non-volatile memory blocks has been exceeded. A memory block management function is triggered upon determining that the error count margin threshold of any of the non-volatile memory blocks has been exceeded.

Claims

1. A system, comprising:

a plurality of non-volatile memory blocks configured to store data; and

a controller and logic integrated with and/or executable by the controller, the logic being configured to, for at least some of the plurality of non-volatile memory blocks;

determine a block health of each non-volatile memory block;

calculate an error count margin threshold for each non-volatile memory block;

determine whether the error count margin threshold of any of the non-volatile memory blocks has been exceeded; and

trigger a memory block management function upon determining that the error count margin threshold of any of the non-volatile memory blocks has been exceeded.

2. The system as recited in claim 1, wherein the memory block management function includes setting an indicator.

3. The system as recited in claim 1, wherein the memory block management function includes performing an immediate calibration of at least the non-volatile memory blocks having the exceeded threshold.

4. The system as recited in claim 1, wherein the memory block management function includes scheduling a calibration of at least the non-volatile memory blocks having the exceeded threshold, wherein the calibration is scheduled to be performed during a subsequent background health check.

5. The system as recited in claim 1, wherein the memory block management function includes scheduling a calibration of at least the non-volatile memory blocks having the exceeded threshold, wherein the calibration is performed during a currently ongoing background health check iteration.

6. The system as recited in claim 1, wherein the logic is configured to:

reduce the block health of the non-volatile memory blocks having the exceeded threshold.

7. The system as recited in claim 1, wherein a non-volatile memory block is retired when the error count margin threshold of the non-volatile memory block reaches a block retirement error count limit.

8. The system as recited in claim 1, wherein the error count margin threshold of each non-volatile memory block is individually updated over time, wherein the memory block management function includes scheduling a calibration of at least the non-volatile memory blocks having the exceeded threshold, wherein the calibration is performed during a currently ongoing background health check iteration, wherein an order in which the calibration of at least the non-volatile memory blocks having the exceeded threshold is performed is determined by a priority level associated with each of the non-volatile memory blocks.

9. The system as recited in claim 1, wherein the non-volatile memory is a NAND Flash memory.

10. A method, comprising:

determining, using a controller, a block health of each of at least some non-volatile memory blocks of a plurality of non-volatile memory blocks;

wherein the plurality of non-volatile memory blocks are configured to store data;

calculating an error count margin threshold for each of the at least some non-volatile memory blocks;

determining whether the error count margin threshold of any of the at least some non-volatile memory blocks has been exceeded; and

triggering a memory block management function upon determining that the error count margin threshold of any of the non-volatile memory blocks has been exceeded.

11. The method as recited in claim 10, wherein the memory block management function includes setting an indicator.

12. The method as recited in claim 10, wherein the memory block management function includes performing an immediate calibration of at least the non-volatile memory blocks having the exceeded threshold.

13. The method as recited in claim 10, wherein the memory block management function includes scheduling a calibration of at least the non-volatile memory blocks having the exceeded threshold, wherein the calibration is scheduled to be performed during a subsequent background health check.

14. The method as recited in claim 10, wherein the memory block management function includes scheduling a calibration of at least the non-volatile memory blocks having the exceeded threshold, wherein the calibration is performed during a currently ongoing background health check iteration.

15. The method as recited in claim 10, comprising reducing the block health of the non-volatile memory blocks having the exceeded threshold.

16. The method as recited in claim 10, wherein a non-volatile memory block is retired when the error count margin threshold of the non-volatile memory block reaches a block retirement error count limit.

17. The method as recited in claim 10, wherein the error count margin threshold of each non-volatile memory block is individually updated over time, wherein the memory block management function includes setting an indicator for each of the non-volatile memory blocks having an exceeded error count margin threshold, wherein an additional action is performed on each of the non-volatile memory blocks having a corresponding indicator set, wherein the additional action is selected from a group consisting of:

performing an immediate calibration of each of the non-volatile memory blocks having the corresponding indicator set, scheduling a calibration of each of the non-volatile memory blocks having the corresponding indicator set, and reducing the block health of each of the non-volatile memory blocks having the corresponding indicator set.

18. The method as recited in claim 10, wherein the non-volatile memory is a NAND Flash memory, wherein calculating the error count margin threshold for each of the at least some non-volatile memory blocks includes adding a given percentage of an error count equivalent of the current block health value to the error count equivalent of the current block health value.

19. A computer program product comprising a computer readable storage medium having program instructions embodied therewith, the program instructions readable and/or executable by a controller to cause the controller to:

determine, by the controller, a block health of each of at least some non-volatile memory blocks of a plurality of non-volatile memory blocks;

wherein the plurality of non-volatile memory blocks are configured to store data;

calculate, by the controller, an error count margin threshold for each of the at least some non-volatile memory blocks;

determine, by the controller, whether the error count margin threshold of any of the at least some non-volatile memory blocks has been exceeded; and

trigger, by the controller, a memory block management function upon determining that the error count margin threshold of any of the non-volatile memory blocks has been exceeded.

20. The computer program product as recited in claim 19, wherein the non-volatile memory is a NAND Flash memory, wherein the error count margin threshold of each of the at least some non-volatile memory blocks is individually updated over time, with a proviso that Flash memory block index tables are not maintained and/or monitored.