Adaptive Storage L2P Consolidation for Trapped mSets
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Solution Overview
Problem
The inefficiency in consolidating logical-to-physical (L2P) table mappings in storage devices leads to increased write amplification and reduced RAM capacity due to trapped mSets, which are not frequently updated and occupy space indefinitely, necessitating costly and time-consuming scans to identify and consolidate.
Innovation Solution
A controller in the storage device increments global and local counters for each L2P mapping update, selecting regions for consolidation based on counter thresholds to timely release trapped mSets during background and foreground operations, optimizing RAM usage and reducing write amplification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the L2P table consolidates all mSets frequently to prevent trapped mSets, then RAM space is freed up, but write amplification increases due to frequent consolidation operations
Solution Approach 1:
The patent changes the parameter of consolidation frequency from fixed/frequent to dynamic/adaptive based on mSet age and activity. By monitoring how long mSets have been trapped and their update frequency, the system adjusts consolidation timing to free RAM space only when necessary, rather than performing frequent consolidations that increase write amplification.
Solution Approach 2:
The system implements self-service by automatically identifying and consolidating trapped mSets based on predefined criteria (age thresholds, update frequency) without requiring external intervention or frequent full-table consolidations. The L2P table manages its own space optimization through targeted consolidation of only the trapped portions.
2Loss of information
If the storage device scans memory blocks to identify trapped mSets, then trapped mSets are detected and can be consolidated, but processing time and computational cost increase
Solution Approach 1:
The patent applies preliminary action by maintaining metadata (such as timestamps and update counters) that tracks mSet activity and age in advance. This preliminary tracking allows the system to identify trapped mSets without performing time-consuming scans, as the identification information is already prepared and maintained during normal operation.
Solution Approach 2:
The system introduces an intermediary mechanism (metadata tracking structure) that mediates between the L2P table data and the consolidation process. This intermediary maintains information about mSet age and activity, enabling efficient identification of trapped mSets without directly scanning the entire memory block structure.
3Productivity
If trapped mSets are retained in RAM indefinitely, then RAM capacity is reduced, but consolidation operations become less frequent
Solution Approach 1:
The patent changes the parameter of mSet retention from indefinite to time-bound based on age thresholds and activity monitoring. By implementing dynamic parameters that track how long mSets have been trapped and their update frequency, the system frees RAM space proactively before it becomes completely full, maintaining both adequate RAM capacity and optimized consolidation frequency.
Data Source
AI summary
A storage device may optimize consolidation of a logical to physical (L2P) table stored on a volatile memory. A controller may execute a request to store data to a memory device and add a new L2P mapping to the L2P table. The controller may increment a global counter and a local counter associated with a region in the L2P table when data associated with the region is added on the memory device. The controller may select the region in the L2P table for consolidation during a background operation based on a background threshold or during a foreground operation based on a foreground threshold. In selecting the region, the controller may select the region if the difference between the global counter and the local counter is greater than a counter threshold. The controller may consolidate the selected region.