Flash Memory Trim Command Handling via L2P Segmentation
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Solution Overview
Problem
The existing flash memory systems face inefficiencies and latency issues when handling trim commands due to the need to update logical-to-physical (L2P) address mapping tables, which are triggered by both trim commands and normal write operations, leading to conflicts during power-on data rebuild processes.
Innovation Solution
The method involves modifying L2P address mapping entries according to trim commands and storing only trim information, including the start logical block address and trim length, into data blocks of the flash memory, rather than storing the entire modified mapping entries, thereby improving efficiency and reducing latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the flash memory controller stores modified L2P address mapping entries to the flash memory after trim commands, then data consistency is maintained, but the handling time increases significantly due to the need to deal with both trim command changes and normal write operation changes
Solution Approach 1:
The patent segments the storage of L2P address mapping changes by separating trim command changes from normal write operation changes. Trim commands are handled through a dedicated mechanism that stores only trim information (start LBA and length) rather than full mapping entries, while normal write operations continue to update the mapping table as before. This segmentation allows the system to maintain data consistency without the performance penalty of processing all changes uniformly.
Solution Approach 2:
The patent extracts the essential information from trim commands (start LBA and trim length) and stores only this extracted information in the flash memory, rather than storing the complete modified L2P address mapping entries. This extraction reduces the amount of data that needs to be written to flash memory during trim operations, significantly reducing handling time while maintaining the ability to reconstruct the full mapping state when needed.
2Productivity
If the flash memory controller updates the L2P address mapping table for both trim commands and normal write operations, then address translation efficiency is maintained, but conflicts arise during power-on data rebuild processes
Solution Approach 1:
The patent applies preliminary action by processing and storing trim command information immediately when received, before any potential conflicts arise during power-on data rebuild. The trim information is stored in a dedicated manner that allows it to be applied correctly during subsequent operations, ensuring that address translation efficiency is maintained while preventing conflicts during power-on rebuild processes.
3Reliability
If the flash memory controller stores complete modified L2P address mapping entries after trim commands, then data validity is ensured, but the burden on garbage collection operations increases
Solution Approach 1:
The patent extracts only the essential trim information (start LBA and length) from the complete L2P address mapping entries and stores this condensed information in the flash memory. This extraction reduces the amount of data that garbage collection operations need to process, thereby reducing the burden on GC while still maintaining the ability to ensure data validity through the stored trim information.
Data Source
AI summary
A method of handling trim commands in a flash memory is provided. The method comprises: receiving a trim command; modifying logical-to-physical (L2P) address mapping entries of a L2P address mapping table according to the trim command; and storing trim information of the trim command into one of data blocks of the flash memory after modifying the L2P address mapping entries according to the trim command.