Dynamic Garbage Collection Controller for SSD Memory
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Solution Overview
Problem
Current memory systems face inefficiencies in garbage collection, leading to host traffic stalls and excessive over-provisioning space loss due to inflexible garbage collection rates that do not adapt to changing demand.
Innovation Solution
Implementing a 'just in time' garbage collection method with a controller that dynamically selects garbage collection units based on variable threshold numbers, ensuring a balance between garbage collection rate and host input/output demand, thereby maintaining sufficient over-provisioning space and preventing traffic stalls.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a fixed high garbage collection rate is maintained, then garbage collection efficiency is improved, but host traffic stalls occur and over-provisioning space is excessively lost
Solution Approach 1:
The patent implements dynamic adjustment of garbage collection rate based on real-time monitoring of over-provisioning space and host traffic conditions. The controller varies the garbage collection rate within a range rather than maintaining a fixed rate, allowing the system to adapt to changing conditions and prevent both traffic stalls and excessive space loss.
Solution Approach 2:
The system continuously monitors the state of over-provisioning space and host traffic, using this feedback information to dynamically adjust the garbage collection rate. When over-provisioning space becomes critically low or host traffic shows signs of stalling, the garbage collection rate is automatically reduced or paused, ensuring system stability.
2Productivity
If a fixed high garbage collection rate is maintained, then garbage collection efficiency is improved, but over-provisioning space is excessively lost
Solution Approach 1:
The garbage collection rate is dynamically adjusted based on the current state of over-provisioning space. When over-provisioning space is sufficient, the garbage collection rate can be higher to maintain efficiency. When over-provisioning space becomes critically low, the rate is reduced or paused to prevent excessive space loss and preserve buffer capacity for future write operations.
Solution Approach 2:
The system monitors over-provisioning space levels and uses this feedback to control the garbage collection rate. The controller adjusts the rate in response to space availability, ensuring that garbage collection does not deplete the over-provisioning buffer below safe thresholds, thereby preserving space for handling write amplification and wear leveling requirements.
3Productivity
If garbage collection is performed frequently, then storage space reclamation is improved, but host traffic stalls occur
Solution Approach 1:
The garbage collection rate is dynamically varied based on host traffic conditions. During periods of low host activity, the garbage collection rate is increased to maximize space reclamation. When host traffic increases or shows signs of stalling, the garbage collection rate is reduced or suspended, preventing interference with host operations and avoiding traffic delays.
Solution Approach 2:
The system monitors host traffic patterns and uses this feedback to adjust garbage collection timing and rate. When host traffic is light, garbage collection proceeds at higher rates. When host traffic increases or stalls are detected, the garbage collection process is slowed or paused, ensuring that storage space reclamation does not compromise host traffic performance.
Data Source
AI summary
The disclosure is related to systems and methods of managing a memory. In a particular embodiment, a memory is disclosed that includes multiple garbage collection units. The memory also includes a controller that determines whether to select a garbage collection unit of the multiple garbage collection units for garbage collection based on a variable threshold number of the multiple garbage collection units to garbage collect.