Linux Kernel Technology To Support The Cluster System

Cluster technique has being a hot spot in computer world. Cluster not only makes a good use of the existing resources, but also has good expansibility and higher rate of power and price. Modifying linux kernel code can make linux support cluster technique. There are already a lot of different modification projects. This paper gives a profound analysis of one of these projects, that is, openmosix cluster system. Openmosix modifies linux kernel code and implements the migration of the progress in linux kernel space.This paper analyzes linux kernel source code, and then studies the code of openmosix and the principle of process migration. When openmosix migrates processes, it just migrates user spaces but not moves kernel space. Through analysis, it is found that some kernel structures can be migrated and the migrations can improve the performance of cluster .So a project is proposed to migrate socket. This project is mainly directed at the shortage of cluster when it runs server program. For example, a server process is migrated to a remote node. According to the principle of openmosix, when a server process is being migrated, the socket of server process will not be migrated .So if server process intends to read or write socket, it must send request to deputy node. This method wastes not only CPU resource, but also memory resource. So this paper migrates socket to remote node, when kernel migrates server process. Once migration of socket has being implemented, server process will read or write socket on remote node directly. In order to migrate socket, this paper also analyzes IPv4 protocol stack.