memory leakage in system?

[Jeff Davis]

I have in my server 256MB RAM, of which about 220MB is used. Here is a 
command I ran:

# cat /proc/meminfo
      total:    used:    free:  shared: buffers:  cached:
Mem:  261832704 232955904 28876800 76492800 162164736 41222144
Swap: 320774144   192512 320581632
MemTotal:    255696 kB
MemFree:      28200 kB
MemShared:    74700 kB
Buffers:     158364 kB
Cached:       40256 kB
SwapTotal:   313256 kB
SwapFree:    313068 kB
Why so much used? ps aux displays a few httpds and mysqlds as the 
highest by far, but adding up to only a small percentage ( < 25% for all 
httpds and mysqlds, and minute amounts for everything else).

It doesn't seem to make my system run slowly, but it concerns me definately.

Any advice would be appreciated.

Thanks,
  Jeff Davis