Memory Controller Free Block Management During Interrupts
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In non-volatile memory systems, sudden power outages or frequent interrupts can lead to the exhaustion of free memory blocks due to incomplete garbage collection, causing the system to become stuck and unable to secure additional free blocks, which affects performance and stability.
Innovation Solution
A method and apparatus that monitor the number of free blocks and temporarily halt garbage collection during interrupts, invalidating copied data items and delaying map updates until the target block is fully filled, ensuring that free blocks are not prematurely consumed and allowing for stable memory block management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If garbage collection is continuously performed to secure free memory blocks, then the number of free blocks increases, but sudden power outages cause incomplete garbage collection which consumes free blocks and leads to system stagnation
Solution Approach 1:
The patent applies preliminary action by invalidating data items in the victim block before the garbage collection process is complete. When an interrupt occurs during garbage collection, the controller invalidates the data items that were copied to the target block, ensuring that these blocks can be reclaimed as free blocks. This preliminary invalidation prevents the system from becoming stuck due to incomplete garbage collection operations, thereby maintaining system reliability under power interruption while still allowing free blocks to be secured.
2Reliability
If garbage collection is halted during interrupts to preserve free blocks, then system stability is maintained, but the garbage collection process becomes incomplete and free blocks are not secured
Solution Approach 1:
The patent applies the taking out principle by extracting the invalidation operation from the normal garbage collection flow and executing it specifically when an interrupt occurs. Instead of completing the entire garbage collection process or halting it entirely, the controller extracts the data item invalidation step and performs it selectively during interrupt conditions. This allows the system to maintain stability by preserving free blocks while still making progress on garbage collection by invalidating copied data items that can be reclaimed.
3Quantity of substance
If map updates are delayed until target block is fully filled, then free blocks are preserved, but data access performance may be affected
Solution Approach 1:
The patent applies partial action by updating map items selectively rather than waiting for complete target block filling. When an interrupt occurs during garbage collection, the controller updates the map items corresponding to the data items that have been invalidated, even if the target block is not fully filled. This partial map update approach ensures that free blocks are preserved while maintaining data access performance by keeping the mapping information current for the portions of data that have been processed.
Data Source
AI summary
A memory system includes a memory device including plural memory blocks and a controller configured to perform garbage collection on a victim block among the plural memory blocks. The controller is further configured to stop the garbage collection in response to an interrupt and invalidate a valid data item, which is copied from the victim block to a target block during the garbage collection.