On Tue, Dec 14, 2021 at 11:19 AM Eric Snow <ericsnowcurrently@gmail.com> wrote:
There is one solution that would help both of the above in a nice way: "immortal" objects.
FYI, here are some observations that came up during some discussions with the "faster-cpython" team today: * immortal objects should probably only be immutable ones (other than ob_refcnt, of course) * GC concerns are less of an issue if a really high ref count (bit) is used to identify immortal objects * ob_refcnt is part of the public API (sadly), so using it to mark immortal objects may be sensitive to interference * ob_refcnt is part of the stable ABI (even more sadly), affecting any solution using ref counts * using the ref count isn't the only viable approach; another would be checking the pointer itself + put the object in a specific section of static data and compare the pointer against the bounds + this avoids loading the actual object data if it is immortal + for objects that are mostly treated as markers (e.g. None), this could have a meaningful impact + not compatible with dynamically allocated objects -eric