Keep application out of virtual memory?

I'm not sure why you want to do this. The OS puts things into virtual memory when they haven't been used for awhile. So, it's not going to give you this huge boost in performance by trying to pin it in RAM.

Yea, what he said. OSX is really fantastic at utilizing the RAM you give it, whether it's budgeting a limited amount of RAM or maximizing speed with ample RAM. If the app is only using up 500mb of physical RAM then that's all it needs to run as fast as it can without slowing down for HD pageouts and pageins. Nothing you need to worry about.

Virtual memory on OS X is not the same as paged memory or virtual memory in Windows where it is paged out to disk: Just because an application is showing as having a virtual memory size of xGB, it doesn't mean it's paged that memory out to disk.
Have a look here for a bit more info on OS X memory management

Memory management is very complicated in OS X. The only thing you should worry about is pageouts being more frequent than pageins. Open the Terminal and type: top

The last line before the columns of process info shows pageins and pageouts. If the pageouts are higher than the pageins, then you are using VM for swapping running processes. That is when you should worry, otherwise ignore it.