I am running a Mathematica script (this question probably doesn't fit in Mathematica.SE however) and I know that it generally takes up a lot of RAM and loads up my cores. However, althought pgrep MathKernel is showing a pid, I find that top doesn't show this in the top processes, although I notice that it is taking up about 2.25GB of the 8GB available to me.

pmap -x my_process_id

total kB         2243132 1907404 1892108

AND

ps aux | grep MathKernel
dnaneet  20837 12.6 23.3 2234944 1907404 pts/1 Sl   09:23  
 8:01 /share/apps/mathematica/8.0.4/SystemFiles/Kernel/Binaries/Linux-x86-64/MathKernel   -runfirst $TopDirectory="/share/apps/mathematica/8.0.4" -script 
./dcm_10micrometer_2x -- ./dcm_10micrometer_2x

ps aux shows that the process is taking about 12% (In asterisks)

dnaneet  20601  0.0  0.0  68264  1660 pts/1    Ss   09:15   0:00 -bash
**dnaneet  20837 12.2 23.3 2234944 1907404 pts/1 Sl   09:23   8:01 /share/apps/mat**
dnaneet  21922  0.0  0.0  65604   948 pts/1    R+   10:29   0:00 ps -aux

Did this process fail and is the MathKernel just lingering?