Running a Java']Java VM Inside an Operating System Kernel

Operating system extensions have been shown to be beneficial to implement custom kernel functionality. In most implementations, the extensions are made by an administrator with kernel loadable modules. An alternative approach is to provide a run-time system within the operating system itself that can execute user kernel extensions. In this paper, we describe such an approach, where a lightweight Java virtual machine is embedded within the kernel for flexible extension of kernel network I/O. For this purpose, we first implemented a compact Java Virtual Machine with a Just-In-Time compiler on the Intel IA32 instruction set architecture at the user space. Then, the virtual machine was embedded onto the FreeBSD operating system kernel. We evaluate the system to validate the model, with systematic benchmarking.