A garbage collection algorithm combining hot-cold separation and wear leveling in raw flash file systems

Nand Flash is a widely used storage device in embedded systems. Because of its special physical properties, raw flash file systems need to have a garbage collection module to collect invalid data. Traditional garbage collection algorithms do not perform well in the case of data with different hot and cold degrees, which leads to high write amplification. And raw flash file systems such as JFFS and YAFFS do not have a wear leveling module to solve the problem of imbalance erase of blocks, which will cause the life span problem of Nand Flash. In this paper, we propose a garbage collection algorithm that realizes hot-cold separation with a low cost of memory and wear leveling by a bidirectional ordered linked list. The experimental result shows that our algorithm achieves an improvement of 15% in write amplification and a significant improvement in the degree of wear leveling compared to traditional raw flash file systems.