[joshlk]

Asking a silly question… what piece of kernel code do you find the most awe-inspiring or impressive?

[throwaway29303]

Maybe fs/select.c or the polling machinery.

[suprjami]

Agree. The VFS is a delight to read. It's a good intro to the kernel pattern of using function pointers to provide a generic API which other functionality can plug into, simply by implementing the appropriate functions. In this case you'll see all the filesystem drivers implement the VFS operations.