Swap usage when memory is available ..

There is a Linux kernel tuning parameter for swapping, amusingly and aptly name "swappiness", that is discussed here:

http://kerneltrap.org/node/3000

and here:

https://help.ubuntu.com/community/SwapFaq

I have swappiness on my linode set to 100, which works well for me. Even with the parameter set to zero, some swapping will still occur.

James

The logic is that unused or seldom-used RAM is wasted RAM. The kernel will swap out stuff that isn't actively used, and use the freed RAM for caching and other useful things.

There should be a net performance gain, unless you have a strange usage pattern, in which case adjusting swappiness can help.