Quote Originally Posted by wysota View Post
As far as I know this is a normal behaviour. Your kernel prefers to have the block of memory assigned to a given process in case it wants more memory at some later point in time. If you ran out of memory, it'd be freed and assigned to the process being in need of that memory. Try opening a large file, processing it and then repeating with a smaller file. You'll probably notice the memory footprint remains the same, which means the memory for the smaller file was allocated from within the previously deallocated chunk.
I also thought I had a memleak, but after I tested this (loaded a bunch of other applications to fill the memory) my application freed the memory that it no longer used. Thanks wysota!