When does swap decreases

[Francisco Reyes]

On Mon, 20 Jun 2005, Dan Nelson wrote:
> When the system is low on memory, it will force the least used
> blocks of memory to swap.  It will not free the swap space until
> the process owning them exits

Have not found any program to see what programs are using the swap, but as 
I think about it, the current method is not very "smart". I guess any 
other method is difficult to implement.

How wonder how the current method affects performance.
Basically if there is a surge of memory usage and processes start that use 
the swap and these processes are long lived.. I wonder if performance 
will be affected.