1.devtmpfs 的功用是在 Linux 核心 启动早期建立一个初步的 /dev,令一般启动程序不用等待 udev,缩短 GNU/Linux 的开机时间。
2.重要解释
Devtmpfs lets the kernel create a tmpfs very early at kernel initialization, before any driver core device is registered. Every device with a major/minor will have a device node created in this tmpfs instance. After the rootfs is mounted by the kernel, the populated tmpfs is mounted at /dev.In initramfs, it can be moved to the manually mounted root filesystem before /sbin/init is executed.
3.menuconfig 中加入devtmpfs支持
make menuconfig-->Device Drivers-->Generic Driver Options
Maintain a devtmpfs filesystem to mount at /dev
Automount devtmpfs at /dev, after the kernel mounted the rootfs