Dynamic Page Migration Technique for Tiered Memory Systems

Tiered memory systems, which combine a small, fast tier with a large, slow tier, are increasingly recognized as an effective approach to optimizing both performance and cost in memory-intensive workloads. In such systems, page migration plays a central role; however, when the working set size (WSS) exceeds the capacity of the fast memory tier, frequent promotions and demotions can lead to a ping-pong effect that significantly degrades memory bandwidth. This paper proposes a page migration technique that dynamically adjusts the NUMA scan period by detecting changes in WSS based on memory bandwidth. When a large WSS is detected, the scan period is increased to reduce page migrations; conversely, when a small WSS is detected, the scan period is decreased to allow more aggressive page migration. Experiments simulating a CXL-based tiered memory system under dynamically changing WSS demonstrate that the proposed technique achieves up to 21.12% performance improvement compared to the state-of-the-art memory management scheme, TPP.