Quick way to find out path’s in kernel config

You are (Gentoo) linux-user.
You are building packages by yourself.

How many times you have got message “X_Y_Z not enabled in kernel config”, like this (trying to emerge iotop):

 * Checking for suitable kernel configuration options...
 *   CONFIG_TASK_IO_ACCOUNTING:  is not set when it should be.

And sometimes it is pretty hard to find out, exactly where in “make menuconfig” referred config-option lays. Google can give some times answer as first item, sometimes it is not even on 10th page.

There is solution for that : http://kernel.xc.net/
Just choose your kernel version (latest selected by default), and
arch at “Complete config for” and press “Go”

For example you get page like this. All config-options in one page (Help also available) and there you can search (in browser Ctrl+F) option you need and backtrace by indentations how to find it out from menuconfig.

Other, also very useful link is http://lxr.linux.no/ – Linux kernel code cross referenced (if you need to find out where is some type defined, just press link)