[These](https://unix.stackexchange.com/questions/14102/real-memory-usage) [questions](https://unix.stackexchange.com/questions/33541/free-output-format) briefly list the format of the free command, noting that buffers is kernel memory that must be written out to disk and cache is file data that does not need to be written disk.

On my system, unlike most times I have run free, buffers occupies over 10% of RAM. Usually, buffers are a small, almost token, value. 

My question is, what exactly is in the area called buffers? Can I look for it with `lsof`? Does it consist of open file regions that have not been flushed? Is it memory mapped file regions? What is it?

The system runs well and little swap is used, so performance is fine.