[CentOS] Postpone/avoid swaping while there is still free RAM.

Hi people,

I got Centos 4.3 on a 1GB Pentium IV machine. The output of free

-------------------
$ free
             total       used       free     shared    buffers     cached
Mem:       1026896     573848     453048          0       2988     131712
-/+ buffers/cache:     439148     587748
Swap:      1052248     137568     914680
------------------

There is plenty of free ram, but the kernel prefers to swap unused
pages to disk. And later I have to wait for them to be unswapped, the
Desktop looses its promptness - annoying.

In win2k and winXP there is a registry key property which prevents
swapping while there is still RAM.

Do you know whether I can achieve the same in linux?

Best regards!
alex