Flash Memory Controller Zone Reset via Valid Page Count Tables
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Solution Overview
Problem
Existing flash memory management methods are inefficient in handling deallocate commands from host devices, particularly in managing zoned namespaces and determining when to reset zones in flash memory modules.
Innovation Solution
A flash memory controller method that receives settling commands to configure zoned namespaces, writes data into blocks, establishes a zone-block mapping table, updates a valid page count table after data is written, and sends a reset command when all blocks in a zone have zero valid page counts, facilitating efficient memory management and zone reset.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the flash memory controller uses traditional memory management methods to handle deallocate commands, then the host device can send deallocate commands, but the processing efficiency is low and the controller cannot quickly determine when zones are empty
Solution Approach 1:
The patent pre-allocates and maintains a valid page count table that tracks the number of valid pages in each block before deallocate commands are processed. This preliminary tracking structure allows the controller to quickly update and check zone empty states without performing extensive searches or calculations when deallocate commands arrive, significantly improving processing efficiency and reducing time to determine when zones are empty.
Solution Approach 2:
The patent introduces a valid page count table as an intermediary data structure between the host device's deallocate commands and the physical flash memory blocks. This intermediary table absorbs the complexity of tracking valid pages across multiple blocks and zones, allowing the controller to efficiently query zone empty states by simply checking the aggregated valid page counts in the table rather than examining each block individually.
2Measurement precision
If the flash memory controller maintains detailed tracking of all blocks and zones, then it can accurately determine when zones are empty, but the memory management complexity increases
Solution Approach 1:
The patent segments the flash memory namespace into zones with continuous logical addresses, and further segments tracking at the block level within each zone. The valid page count table is organized to aggregate block-level information at the zone level, allowing the controller to maintain precise tracking of empty zones through a hierarchical structure that reduces overall complexity compared to tracking every individual page or block separately.
Solution Approach 2:
The patent creates a simplified copy or representation of the physical block structure in the valid page count table, where each entry represents aggregated valid page information for a block or zone rather than storing detailed information about every individual page. This copying approach maintains measurement precision for determining zone empty states while significantly reducing the complexity of the data structures the controller must manage.
Data Source
AI summary
The present invention provides a control method of the flash memory controller. In the control method, after receiving a deallocate command from a host device, the flash memory controller will update a valid page count table, a detailed valid page count table and/or a zone valid page count table according to deallocate command, for the flash memory controller to efficiently and quickly determine if any one of the zones does not have any valid data, so that the flash memory controller can recommend the host device to send a reset command to reset the zone.