UFS based idle time garbage collection management
AssigneeMicron Technology, Inc.
InventorsKulachet Tanpairoj, Jianmin Huang, Kishore Kumar Muchherla
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Abstract
Disclosed in some examples are systems, methods, NAND memory devices, and machine readable mediums for intelligent SLC cache migration processes that move data written to SLC cache to MLC storage based upon a set of rules that are evaluated using the state of the NAND device. In some examples, the SLC cache migration process may utilize a number of NAND operational parameters to determine when to move the data written to SLC cache to MLC, how much data to move from SLC to MLC, and the parameters for moving the data.
Claims19
A method of operating a NAND device, the method comprising:
- at a NAND controller:
- retrieving an SLC cache initiation rule specifying a NAND operational condition for migration of data stored in an SLC cache to MLC memory cells and a source selection rule specifying an order for migrating data stored in the SLC cache;
- retrieving a first NAND operational condition specified by the initiation rule, and determining whether the first NAND operational condition satisfies the initiation rule;
- and
- responsive to the initiation rule being satisfied, migrating at least a portion of data stored in the SLC cache to MLC memory cells of the NAND device by moving the data stored in the SLC cache in an order specified by the source selection rule, wherein the source selection rule comprises a fragmentation rule and wherein migrating the at least a portion of data stored in the SLC cache to MLC memory cells of the NAND device comprises moving blocks of data in the SLC cache to MLC memory cells in an order based upon the degree of fragmentation of each of the blocks of data in the SLC cache.
A NAND device comprising:
- a controller configured to perform operations comprising:
- retrieving an SLC cache initiation rule specifying a NAND operational condition for migration of data stored in an SLC cache to MLC memory cells and a source selection rule specifying an order for migrating data stored in the SLC cache;
- retrieving a first NAND operational condition specified by the initiation rule, and determining whether the first NAND operational condition satisfies the initiation rule;
- and
- responsive to the initiation rule being satisfied, migrating at least a portion of data stored in the SLC cache to MLC memory cells of the NAND device by moving the data stored in the SLC cache in an order specified by the source selection rule, wherein the source selection rule comprises a fragmentation rule and wherein migrating the at least a portion of data stored in the SLC cache to MLC memory cells of the NAND device comprises moving blocks of data in the SLC cache to MLC memory cells in an order based upon the degree of fragmentation of each of the blocks of data in the SLC cache.
A non-transitory machine-readable medium, storing instructions, which when executed by a machine, causes the machine to perform operations comprising:
- retrieving an SLC cache initiation rule specifying a NAND operational condition for migration of data stored in an SLC cache to MLC memory cells and a source selection rule specifying an order for migrating data stored in the SLC cache;
- retrieving a first NAND operational condition specified by the initiation rule, and determining whether the first NAND operational condition satisfies the initiation rule;
- and
- responsive to the initiation rule being satisfied, migrating at least a portion of data stored in the SLC cache to MLC memory cells of the NAND device by moving the data stored in the SLC cache in an order specified by the source selection rule, wherein the source selection rule comprises a fragmentation rule and wherein migrating the at least a portion of data stored in the SLC cache to MLC memory cells of the NAND device comprises moving blocks of data in the SLC cache to MLC memory cells in an order based upon the degree of fragmentation of each of the blocks of data in the SLC cache.
Dependencies are inferred from the claim text.