Thinking about A New Mechanism for Huge Page Management

The Huge page mechanism is proposed to reduce the TLB misses and benefit the overall system performance. On the system with large memory capacity, using huge pages is an ideal choice to alleviate the virtual-to-physical address translation overheads. However, using huge pages might incur expensive memory compaction operations due to memory fragmentation problem, and lead to memory bloating as many huge pages are often underutilized in practice. In order to address these problems, in this paper, we propose SysMon-H, a sampling module in OS kernel, which is able to obtain the huge page utilization in a low overhead for both cloud and desktop applications. Furthermore, we propose H-Policy, a huge page management policy, which splits the underutilized huge pages to mitigate the memory bloating or promotes the base 4KB pages to huge pages for reducing the TLB misses based on the information provided by SysMon-H. In our prototype, SysMon-H and H-Policy work cooperatively in OS kernel.