Linux's dentry_cache takes all available memory

So for some reason one of my servers had 12G of memory allocated to the dentry_cache that wasn't being reclaimed. Probably a bug in the old version of the Linux kernel that this server is using. The solution that worked for me was:

# sync && echo 2 >/proc/sys/vm/drop_caches

If you're curious as to what this does, RTFM.

I like it!