malloc and free problems

[Scott Le Grand]

Hi, I wish to allocate 10 times as much memory as I really need to initialize
some data.  I use malloc to do this, and then use free to dispose of the 90%
I am not going to use during execution (I am sampling the top 10% of a
randomly generated distribution).  When I use free on it, I find I am still
using the huge amount of memory I started with, even after supposedly
disposing of it.  What is going on here?

Scott