Mark Shannon <m...@hotpy.org> added the comment:
A big -1 to this. You are asking the whole world to take a hit on both performance and memory use, in order to save Instagram memory. The PR uses the term "immortal" everywhere. There is only one reference to copy-on-write in a comment. Yet this issue about making object headers immutable. Immortality and object header immutability are not the same. If object header immutability is to be a requirement, that needs a PEP. If it is not requirement, but immortality is, then make the obvious improvement of changing the branchy code if (!(obj->refcnt & IMMORTAL_BIT)) { obj->refcnt++; } to the branchless obj->refcnt += ((obj->refcnt &IMMORTAL_BIT) != 0) Immortality has advantages because it allows saturating reference counting and thus smaller object headers, but it is not the same as making the object header immutable. ---------- nosy: +Mark.Shannon _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue40255> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com