Comment # 59 on bug 1159882 from Robert Delahunt

Your most recent kernel with cgroup_disable=memory shows no swap usage when
copying 16GB of data between drives.  There was plenty of time to observe RAM
get used up (monitoring free -m every second using a script) but it not resort
to using swap.  I double-checked and swappiness is set to 60 right now, so it
would have had plenty of authority to swap out.  vfs_cache_pressure=100 as
well.  Default system values.

http://www.puresimplicity.net/~delahunt/vmstat/mhocko3/

There are the vmstat files for your convenience.

Please let me know what else I can do to help eradicate this bug.