Where 3GB space got consumed?

[lalitpratap]

I have compiled linux kernel 3.1.2 (latest stable) yesterday on my Ubuntu 11.10.
After installation i found that it consumed almost 8GB more of my hard disk space.
Later when i figure out that the compilation directory(/usr/src/linux-kernel-3.1.2) took almost 5GB of space in source directory. But still unable to figure out where rest 3GB space get consumed. I am still wondering where this space get consumed. Anyone having any idea that how can recover that space?

[Schugy]

sudo apt-get install gnome-utils
sudo baobab

Are you sure that you haven't built a huge debug kernel?

CONFIG_DEBUG_KERNEL=N