1 根文件系统
简单来说，（根文件系统）就是系统第一个mount的文件系统
Filesystem Handling
Like every traditional Unix system, Linux makes use of a system 's root filesystem : it is the filesystem that is directly mounted by the kernel during the booting phase and that holds the system initialization scripts and the most essential system program.
Other filesystems can be mounted either by the initialization scripts or directly by the users on directories of already mounted filesystems. Being a tree of directories every filesystem has its own root directory. The directory on which a filesystem is mounted is called the mount point. A mounted filesystem is a child of the mounted filesystem to which the mount point directory belongs. For instance, the /proc virtual f
1 进程管理相关代码
1.1 thread_info结构，在文件<asm/thread_info.h>中定义
struct thread_info {
struct task_struct *task;
struct exec ......
