Python Memory Manager

[Pie Squared]

I've been looking at the Python source code recently, more
specifically trying to figure out how it's garbage collector works.

I've gathered that it uses refcounting as well as some cycle-detection
algorithms, but I haven't been able to figure out some other things.

Does Python actually have a single 'heap' where all the data is
stored? Because PyObject_HEAD seemed to imply to me it was just a
linked list of objects, although perhaps I didnt understand this
correctly.

Also, if it does, how does it deal with memory segmentation? This
question bothers me because I've been trying to implement a moving
garbage collector, and am not sure how to deal with updating all
program pointers to objects on the heap, and thought perhaps an answer
to this question would give me some ideas. (Also, if you know any
resources for things like this, I'd be grateful for links/names)

Thanks in advance,

Pie Squared