Hide kernel processes in top with LIBPROC_HIDE_KERNEL

LIBPROC_HIDE_KERNEL=1 top

Although the question has aged a bit, there is an interesting new approach: Since version 4 of the procps package, you can set the environment variable LIBPROC_HIDE_KERNEL. If set, ps(1) and top(1) will display user space processes, only.

Source: unix.stackexchange.com