What's using all of the memory in my VM? It's not the disk cache

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http://unix.stackexchange.com – I have an issue where when I try to build a really large project, my machine starts swapping (several GB) even though there's plenty of memory (14 GB in fact). When I run free, it shows that it's not the disk cache: $ free -m total used free shared buffers cached Mem: 12900 6350 6549 0 7 77 -/+ buffers/cache: 6266 6633 Swap: 9211 233 8978 So 6.3 GB of memory is actually in use, but if I look at top, sorted by % memory usage, nothing is using any memory: PID USER PR NI (HowTos)