Can a process running a 32-bit compiled binary use more than 4GB of memory?

Question

Is it possible for a single process running a 32-bit compiled version of python in Snow Leopard (64-bit machine) to appear to consume > 4GB (say 5.4GB) of virtual memory as seen by the top command?

I did a file ...python to see that the binary was not x86, yet it appeared to be consuming over 5GB of memory.

My guess is that the libraries that were used (RPy) were 'mmap'ing chunks of data, and the in-memory cache was appearing under the memory footprint of my process.

Or maybe I haven't verified that the Python binaries were 32-bit. Or maybe there's some 32-bit/64-bit commingling going (libffi?).

Totally confused.

Answer 1

No, it's physically impossible. That doesn't stop the OS assigning more than it can use due to alignment and fragmentation, say, it could have a whole page and not actually map in all of it. However it's impossible to actually use over 4GB for any process, and most likely substantially less than that for kernel space.

Answer 2

It is possible if the processes is using some kind of insane long/far/extended pointers and mapping data into and outof a 32-bit address space as it needs it, but at that point it hardly qualifies as 32-bit anyway. (Python most definitely does not do this, so @DeadMG's answer is almost certainly what is actually happening.)