Cache Management via Storage Invalidation Feedback
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Solution Overview
Problem
Conventional cache management systems fail to effectively reclaim cache pages associated with invalid data, leading to reduced cache hit ratio and performance, as they rely solely on the Least Recently Used (LRU) algorithm without considering data validity, resulting in retention of invalid backend data and premature reclamation of valid data.
Innovation Solution
A method and device for cache management that involves receiving an indication of an invalid storage block, looking up the associated cache page, determining data validity, and reclaiming the cache page only if it is invalid, thereby prioritizing the retention of valid data and optimizing cache performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the LRU algorithm is used for cache management, then the cache can be managed automatically, but invalid data in the cache cannot be reclaimed, leading to reduced cache hit ratio
Solution Approach 1:
The system establishes a feedback mechanism where the storage device notifies the cache management system about invalid storage blocks. The cache management system then uses this feedback information to identify and reclaim corresponding invalid cache pages, transforming the passive LRU approach into an active validity-aware management system.
Solution Approach 2:
The system performs preliminary action by proactively reclaiming cache pages before they are needed, based on the invalidation information received from the storage device. This prevents invalid data from occupying cache space and improves hit ratio without requiring complex real-time validation checks during read operations.
2Productivity
If cache pages are reclaimed based on LRU algorithm, then cache space is freed, but valid data may be mistakenly reclaimed while invalid data is retained
Solution Approach 1:
The system applies local quality by differentiating the treatment of cache pages based on their data validity status. Instead of uniform LRU-based reclamation, the system selectively reclaims only those cache pages whose corresponding storage blocks are marked as invalid, while preserving valid data in the cache.
Solution Approach 2:
The cache management system acts as an intermediary between the storage device and the cache, using the invalidation information as a mediator to make informed reclamation decisions. This intermediary role allows the system to coordinate cache management actions with the actual data validity state in the storage device.
3Reliability
If invalid cache pages are not reclaimed, then cache structure remains simple, but cache hit ratio decreases and performance deteriorates
Solution Approach 1:
The system performs preliminary action by proactively reclaiming cache pages before they are needed, based on the invalidation information received from the storage device. This prevents invalid data from occupying cache space and improves hit ratio without requiring complex real-time validation checks during read operations.
Solution Approach 2:
The cache management system leverages the invalidation information already provided by the storage device to automatically identify and reclaim invalid cache pages. This self-service approach improves performance by utilizing existing information rather than requiring additional complex validation mechanisms.
Data Source
AI summary
Embodiments of the present disclosure provide a method, device and computer program product for cache management. The method includes: receiving from a storage device an indication for an invalid storage block in the storage device; in response to receiving the indication, looking up a cache page associated with the invalid storage block in the cache; in response to finding the cache page in the cache, determining validity of data in the cache page; and in response to the data being invalid, reclaiming the cache page.