Probability-based remedial action for read disturb effects
A method may be performed in a data storage device that includes a memory and a controller, in response to a request to read data from the memory. The data is located within a first word line of the memory. The method includes accessing the data from the first word line and determining, based on a probability threshold, whether to perform a remedial action with respect to a second word line.
1. A data storage device comprising:
a memory including a first word line and a second word line; and
a controller, wherein the controller is configured to access data from the first word line, to determine, based on a probability threshold, if a remedial action is to be performed with respect to the second word line, and if the remedial action is determined to be performed, to initiate the remedial action with respect to: data stored in the second word line, and a different word line.
2. The data storage device of claim 1 , wherein:
the remedial action includes scheduling the data stored in the second word line for a data move operation.
3. The data storage device of claim 1 , wherein:
the remedial action includes reassigning the data stored in the second word line to the different word line.
4. The data storage device of claim 1 , wherein the probability threshold is based on a read disturb threshold associated with the second word line.
5. The data storage device of claim 1 , wherein:
the controller is further configured, in response to a read request, to generate a value associated with the second word line, to perform a comparison of the value to the probability threshold, and to determine, based on the comparison, whether to perform the remedial action, and
the remedial action includes reassigning the data stored in the second word line to the different word line of the memory.
6. The data storage device of claim 5 , wherein the controller is configured to generate the value randomly, semi-randomly, or pseudo-randomly.
7. The data storage device of claim 6 , wherein the value is selected from a range of values, wherein the probability threshold corresponds to a sub-range of the range of values, wherein the remedial action includes reassigning data stored in a third word line to a second different word line of the memory, and wherein the second word line is a neighbor of the first word line and the third word line is an edge word line of a memory block that includes the first word line and the second word line.
8. The data storage device of claim 1 , wherein the controller is configured to determine a number of errors in the data stored in at least a portion of the second word line, and wherein a particular determination of whether to perform the remedial action is based on the number of errors in the data stored in the at least a portion of the second word line.
9. The data storage device of claim 1 , wherein the second word line is a neighbor of the first word line, and wherein the memory includes a non-volatile memory.
10. The data storage device of claim 1 , wherein the controller is configured to retrieve the data from the first word line, to decode the retrieved data to generate decoded data, and to provide the decoded data to a host device in response to a request to read the data.
11. The data storage device of claim 1 , wherein the controller is configured to perform the remedial action by adding an entry corresponding to the second word line into a reassignment queue.
12. A data storage device comprising:
a memory including a first word line and a second word line; and
a controller, the controller configured to access data from the first word line, to determine based on a probability threshold if a remedial action is to be performed with respect to the second word line, the probability threshold based on a read disturb threshold associated with the second word line, and if the remedial action is determined to be performed, to initiate the remedial action with respect to: data stored in the second word line, and a different word line.
13. The data storage device of claim 12 , wherein:
the remedial action includes scheduling the data stored in the second word line for a data move operation.
14. The data storage device of claim 12 , wherein the read disturb threshold is inversely proportional to a count of write/erase cycles, and wherein the controller is configured to select the probability threshold based on the count of write/erase cycles.
15. A method comprising:
in a data storage device that includes a memory and a controller, wherein the memory is configured to store data within a first word line of the memory, performing:
accessing the data from the first word line;
determining, based on a probability threshold, if a remedial action is to be performed with respect to a second word line of the memory; and
if the remedial action is determined to be performed, initiating the remedial action with respect to: data stored in the second word line, and a different word line of the memory.
16. The method of claim 15 , wherein:
the remedial action includes reassigning the data stored in the second word line to the different word line.
17. The method of claim 15 , wherein determining, based on the probability threshold, if the remedial action is to be performed comprises performing a probability-based test by generating a value and comparing the value to the probability threshold, and wherein the value is generated randomly, semi-randomly, or pseudo-randomly.
18. The method of claim 15 , wherein:
the probability threshold is based on a read disturb threshold associated with the second word line, and
the remedial action is performed if a generated value satisfies the probability threshold.
19. The method of claim 15 , further comprising setting the probability threshold based on a read disturb threshold associated with the second word line, wherein the remedial action includes scheduling the data stored in the second word line for a data move operation.
20. The method of claim 19 , wherein the read disturb threshold is based on a count of write/erase cycles.
21. The method of claim 20 , wherein the read disturb threshold is inversely proportional to the count of write/erase cycles.
22. A method comprising:
in a data storage device that includes a memory and a controller, wherein the memory is configured to store data within a first word line of the memory, performing:
accessing the data from the first word line;
determining, based on a probability threshold, if a remedial action is to be performed with respect to a second word line of the memory; and
if the remedial action is determined to be performed, initiating the remedial action with respect to: data stored in the second word line, and a different word line of the memory.
23. The method of claim 22 , wherein the remedial action includes scheduling the data stored in the second word line for a data move operation.
24. The method of claim 22 , wherein the second word line is a neighbor of the first word line, and wherein a third word line is an edge word line of a memory block that includes the first word line and the second word line.
25. The method of claim 22 , further comprising determining a number of errors in the data stored in the second word line, wherein determining if the remedial action is to be performed is based on the number of errors in the data stored in the second word line.
26. The method of claim 22 , further comprising:
determining a count of write/erase cycles associated with the second word line; and
generating the probability threshold based on the count of write/erase cycles, wherein the second word line is a neighbor of the first word line.
27. The method of claim 22 , further comprising:
in response to a determination to perform the remedial action, adding an entry corresponding to the second word line into a reassignment queue;
after the entry is added to the reassignment queue, performing a background operation, wherein the remedial action is performed during the background operation; and
removing the entry from the reassignment queue after the remedial action is performed.