Bug report
Bug description:
Toward the tail end of sys._debugmallocstats() output there's an account of bytes sitting in various type-specific free lists, like so:|
62 free PyDictObjects * 48 bytes each = 2,976
77 free PyDictKeysObjects * 32 bytes each = 2,464
6 free PyFloatObjects * 24 bytes each = 144
60 free PyListObjects * 40 bytes each = 2,400
231 free 1-sized PyTupleObjects * 40 bytes each = 9,240
...
However, for the container types that participate in cyclic gc (dict, list, tuple), the "bytes each" figurers are too small. Like:
Python 3.14.1 (tags/v3.14.1:57e0d17, Dec 2 2025, 14:05:07) [MSC v.1944 64 bit (AMD64)] on win32 Type "help", "copyright", "credits" or "license" for more information. >>> import sys >>> sys.getsizeof([]) 56
56 > 40, by 16. Same 16 missing for dicts and tuples. I suspect (but don't know) that they're missing the two pointers (before the PYObject's type pointer) used by cyclic gc to link together the members of a generation.
Labeling as "easy", because it has to 😉 be shallow. A good exercise for somene to sharpen their archeological skills.
CPython versions tested on:
3.14
Operating systems tested on:
Windows