Apologies if I misunderstand things completely, I am no developer so memory management is completely foreign to me. Are the steps you describe involving the creation of a file and mmap it, to be used in the shell, and the output then applied to a process already running (say some python code) or are they supposed to be performed before the python code is run? In the first case, how do I assign this points to the process already running? I assume this will be extra virtual memory on top of the one the VMM has already used for the process. In the second case, does the pointer have to be used within the python script (that is, do I need to modify my python script in a certain way to tap into this file for virtual memory)? Or once I have it, I have to launch the process in a certain way that it uses it? Feel free to refer me to some resource that explains how to map a file to a process, all I could find, manages included, was not helpful and does not go into enough detail for my background. There is no mention of the process' PID, so I am quite confused about how to let the process know that it can use this file via the pointer. Further, once this is set-up, will the process still use the available physical ram or it will only use the file? One important clarification for my use case, in the eventuality that the script has to be modified via mmap, is that the python process I need to use the mapped file uses a gurobi routine. Only this routine is the memory heavy part. However, this is proprietary software (written in C) which I cannot modify nor have access to. I simply call it through a python API with a command: model.optimize(). Thus I fear, in this case, that mmap is not an option as I do not find any mention of it in the gurobi documentation.

I see, thank you for the explanation. Yes, my machine has 16 GB of RAM and I read about the VMM at https://developer.apple.com/library/archive/documentation/Performance/Conceptual/ManagingMemory/Articles/AboutMemory.html#//apple_ref/doc/uid/20001880-BCICIHAB Is there a guide for macOS on the steps you describe at the end, that is on how to allocate a swapfile, mmap that swapfile into memory, then use that mapped memory instead of system-allocated memory? I am familiar with dd from /dev/zero etc and the usual declaration of a swapfile by appending on /etc/fstab, but that is in Linux, and perhaps that does not work on macOS...

Thank you so much for your reply, now I have a picture of what is going on. Could you share also how to use these functions? The only documentation I could find does not have examples. Say I have, among all, this process running, labelled python3 with PID 33238. I tried writing os_proc_available_memory() in my terminal (bash shell), and all I get is a prompt > awaiting for input. Same with getrlimit and setrlimit. I tried also os_proc_available_memory(33238) etc but I get error messages. The documentation keep mentioning 'the current process' but there are many, how do I run this functions relative to a specific ongoing process?