Memory Monitoring Tool

Is there a tool to see who is using memory. Somethings is using up all my memory on a test machine that I have running the new 2.6 kernel . When I list the processes or look at top I cannot find a anything that is doing it. So is there a tool that can low level and tell me who used the memory or why its not being freed?

Thanks

Are you having any problems with this machine? Is it running slow? An application will hold that memory until either it will use it again or another app. needs it, then the necessary memory will be released to run said app. This is the way linux works.

Yes I noticed it was running slower. So when I tried to investigate i notice that almost all of the 2 Gig memory is being used up. But when I do a process listing and a top I cannot find a process that is using the memory. I even went thourgh the /proc directory to maybe find something else out but I cant find anything in there either.

I worried that it may be kernel related(ie a module or kernel feature) so I am looking for a low level tool to tell my what could be using all this memory.

This might help:

http://www.linuxgazette.com/issue25/ayers2.html

Cheers :)