In my experience, the linux kernel handles no swap at all very badly, so you need a small amount.
Increasing the swap, which is the suggested solution, is however, a terrible idea. As soon as you hit high memory usage, your IO load will go through the roof, and everything will grind to a halt.
The solution here is separation of services - i.e. put Solr on a different box, so that if it spirals it doesn't take out other services.
The OOM killer is your friend for recovering from horrible conditions, but as soon as you hit it or swap, somethings gone wrong.