Re: scratch/igc: Implications of MPS being asynchronous

[Eli Zaretskii]

> From: Gerd Möllmann <gerd.moellmann@gmail.com>
> Cc: Eli Zaretskii <eliz@gnu.org>,  pipcet@protonmail.com,
>   emacs-devel@gnu.org,  gerd@gnu.org,  eller.helmut@gmail.com
> Date: Mon, 13 Jan 2025 05:09:00 +0100
> 
> Stefan Kangas <stefankangas@gmail.com> writes:
> 
> > Eli Zaretskii <eliz@gnu.org> writes:
> >
> >>> From: Stefan Kangas <stefankangas@gmail.com>
> >>> Date: Sun, 12 Jan 2025 16:55:54 +0000
> >>> Cc: pipcet@protonmail.com, emacs-devel@gnu.org, gerd@gnu.org,
> >>>   eller.helmut@gmail.com
> >>>
> >>> (IMHO, the code organization is a bit funny here, because
> >>> garbage_collect() doesn't do what it says on the tin.  I don't think
> >>> it's worth addressing that right now though.  Maybe it's worth taking a
> >>> second look after merging.)
> >>
> >> If we want to add igc_collect somewhere which is called by
> >> garbage-collect, we should add it to garbage_collect, because what you
> >> call "funny" here is quite confusing.  Are there any good reasons not
> >> to call igc_collect from garbage_collect?
> >
> > AFAIU, MPS should decide when to GC, not maybe_gc.
> 
> Maybe I'm misunderstanding something and I haven't read all my mails
> yet, but if this is about calling igc_collect (= mps_arena_collect) in
> some regular code path, I find that a very bad idea. It works against
> MPS as a incremental + generational GC.

Your opinion is that Emacs will never want to intentionally trigger GC
from Lisp?  Can you explain why not?  We do this with the current GC
quite a lot.