/proc filesystem is a pseudo-filesystem and contains
information about the system and running processes.
People frequently panic when they notice one file in particular -
/proc/kcore - which is generally huge. This is (more or less) a
copy of the contents of your computer's memory. It's used to debug the kernel.
It doesn't actually exist anywhere, so don't worry about its size.
Tuning the kernel through the proc
filesystem, Section 7.3 and