Transparently Exploiting Device-Reserved Memory for Application Performance in Mobile System

Abstract— Most embedded systems require contiguous memory space to be reserved for devices, which may lead to memory under-utilization. Although several approaches have been proposed to address this issue, they have limitations of either inefficient memory usage or long latency for switching the reserved memory space between a device and general-purpose uses. Our scheme, on the other hand, utilizes reserved memory as an eviction-based file cache. It guarantees contiguous memory allocation to devices while providing idle device memory as an additional file cache called eCache for general-purpose usage. Because eCache stores only evicted data from the in-kernel page cache, the memory efficiency is preserved and the allocation time for devices is minimized. Cost-based region selection also minimizes additional read I/O operations by carefully discarding cached data from eCache. The additional indexing cost incurred by adding eCache is minimized by integrating its index structure with the kernel page cache. < final year projects >