On Thu, Jan 6, 2022 at 7:00 AM Trent Nelson <[email protected]> wrote: > > I did some research on this a few years back. I was curious what sort > of "max reference counts" were encountered in the wild, in long-running > real life programs. For the same reason: I wanted to get some insight > into how many unused bits could possibly be repurposed for future > shenanigans (I had PyParallel* in the mind at the time). >
I think we can assume the upper bound of the reference count is same to upper bound of the pointer. On 32bit machine, memory space is 2**32 byte, and pointers take 4bytes. And NULL can not store pointer. So upper bound of refcnt is 2**30-1. So we have two free bits in the refcnt. On 64bit machine, we have at least four free bits as same reason. Regards, -- Inada Naoki <[email protected]> _______________________________________________ Python-Dev mailing list -- [email protected] To unsubscribe send an email to [email protected] https://mail.python.org/mailman3/lists/python-dev.python.org/ Message archived at https://mail.python.org/archives/list/[email protected]/message/UNYX6VOQLDMXMWXP54KJUXCHSWOA5YKT/ Code of Conduct: http://python.org/psf/codeofconduct/
