Memory Controller L2P Mapping with Address Boundary Segmentation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing SSDs face challenges in managing large L2P mapping tables due to insufficient address data width, leading to significant DRAM usage and increased costs, especially in high-capacity enterprise SSDs.
Innovation Solution
An address management scheme that organizes physical addresses into categories using address boundaries, eliminating the need to reserve bits for marking address types, thereby reducing the size of the L2P mapping table and DRAM requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the L2P mapping table stores all physical addresses with full address width, then the mapping accuracy is maintained, but the DRAM usage increases significantly
Solution Approach 1:
The physical address space is segmented into multiple regions (first memory region, second memory region, third memory region) with different address width requirements. The L2P mapping table is divided into multiple sub-tables, each storing addresses for specific regions. This segmentation allows the system to use smaller address widths in each sub-table, reducing overall DRAM usage while maintaining full address precision when needed.
Solution Approach 2:
Different regions of the memory space are assigned different address width characteristics. The first memory region uses a smaller address width (e.g., 24 bits) while the second and third regions use larger address widths (e.g., 32 bits). This local quality approach optimizes DRAM usage by matching address width to the actual size of each memory region, rather than using a uniform large address width for all regions.
2Adaptability or versatility
If the address data width is increased to accommodate high-capacity SSDs, then the storage capacity is improved, but the L2P mapping table size increases
Solution Approach 1:
The address management system is segmented into multiple sub-tables, each handling specific address ranges. This allows the system to support high-capacity SSDs with large address spaces while keeping each individual sub-table compact, as each sub-table only needs to store addresses for a specific memory region with appropriate address width.
Solution Approach 2:
The system adds a dimensional organization to the L2P mapping table by creating multiple sub-tables arranged in a hierarchical structure. Instead of a single flat table requiring full address width, the system uses a multi-dimensional structure where sub-tables are indexed by region identifiers, allowing efficient address mapping with reduced width requirements in each dimension.
3Quantity of substance
If the L2P mapping table is optimized to reduce DRAM usage, then the cost is reduced, but the address management complexity increases
Solution Approach 1:
The address management complexity is distributed across multiple simple sub-tables rather than concentrated in one complex table. Each sub-table has a simple, fixed structure optimized for its specific region, making individual sub-tables easy to manage. The overall system complexity is reduced by breaking down the management task into multiple simple, identical operations on different sub-tables.
Solution Approach 2:
Multiple sub-tables use the same unified address boundary (e.g., 24 bits) and similar data structures, creating a universal template that can be applied across all memory regions. This universality simplifies address management by providing a consistent methodology for handling different regions, reducing the need for region-specific complex logic while maintaining flexibility.
Data Source
AI summary
In certain aspects, a memory controller includes a logical-to-physical (L2P) search engine. The L2P search engine is configured to maintain an L2P mapping table that maps logical addresses to physical addresses, respectively. The L2P search engine is also configured to organize the physical addresses mapped by the L2P mapping table into address categories based on at least one address boundary.