Storage Controller Garbage Collection for Mixed-Size Sub-Blocks
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Solution Overview
Problem
The efficiency of garbage collection operations in non-volatile memory devices is degraded due to the size differences between sub-blocks, leading to inefficient management and performance issues.
Innovation Solution
A storage device and controller that independently manage garbage collection operations on sub-blocks of varying sizes by selecting victim sub-blocks based on valid and invalid page counts, using a garbage collection module to copy data and update management tables, and group sub-blocks for efficient resource allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of word lines stacked on a substrate is increased to increase capacity, then the capacity of the non-volatile memory device is improved, but the size of the memory block increases and must be divided into sub-blocks, which complicates the garbage collection operation and degrades its efficiency
Solution Approach 1:
The memory block is divided into multiple sub-blocks with different sizes (first sub-blocks and second sub-blocks), allowing independent management and garbage collection operations on each sub-block type, thereby improving overall garbage collection efficiency while maintaining high capacity
Solution Approach 2:
Different garbage collection strategies are applied to different sub-block types based on their specific characteristics. The controller performs garbage collection on first sub-blocks and second sub-blocks separately, optimizing the process for each local region rather than treating all sub-blocks uniformly
2Ease of operation
If victim sub-blocks are selected without considering size differences between sub-blocks, then the selection process is simplified, but the efficiency of the garbage collection operation degrades
Solution Approach 1:
The garbage collection controller distinguishes between different sub-block types (first sub-blocks and second sub-blocks) and applies size-aware selection criteria when choosing victim sub-blocks, optimizing garbage collection efficiency by considering the specific size characteristics of each sub-block type
Solution Approach 2:
The selection criteria for victim sub-blocks is changed to include size as a parameter. The controller selects victim sub-blocks based on both the number of valid pages and the size of sub-blocks, dynamically adjusting the selection process to maintain high garbage collection efficiency
Data Source
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AI summary
The present disclosure provides storage devices and methods for operating the same. In some embodiments, a storage device includes a non-volatile memory including a plurality of sub-blocks that are independently erasable, and a processor configured to control a garbage collection operation on the plurality of sub-blocks. The plurality of sub-blocks includes a plurality of first sub-blocks that have a first block size and a plurality of second sub-blocks that have a second block size. The second block size is different from the first block size. The processor is further configured to select a victim sub-block with a lowest ratio of a valid page count to an invalid page count from among the plurality of sub-blocks, and copy a valid page of the victim sub-block to a target sub-block from among the plurality of sub-blocks.