Re: MPS: dangling markers

[Gerd Möllmann]

Pip Cet <pipcet@protonmail.com> writes:

> On Sunday, June 30th, 2024 at 13:15, Gerd Möllmann <gerd.moellmann@gmail.com> 
> wrote:
>> Pip Cet pipcet@protonmail.com writes:
>> 
>> > > True. I forgot to mention an important thing: When something is splat,
>> > > set flag(s) in the dependent hash table indicating that something must
>> > > be done because of that splatting. In gethash and so, check the flag and
>> > > do what's necessary. (I did something similar for the weak hash tables
>> > > in CMUCL, and it wasn't entirely bad. And weak tables should be rare.)
>> > 
>> > Not necessarily rare, particularly not if we turn BUF_MARKERS into a
>> > weak hash table (I still don't see why we shouldn't do that, maybe I
>> > missed it).
>> 
>> 
>> Hm, don't know. On the one hand, there's Stefan's gap buffer data
>> structure, and on the other hand add_marker and remove_marker are now
>> O(1) in igc, modulo bugs. So the pressure has decreased.
>
> Well, I needed a weak hash table to test things on, which is why I've
> included the change in the attached patch.

Thanks! What do youo think about making a patch containing only your
weak hash tables, and leaving the BUF_MARKERS alone for now? That way
igc could support the existing uses of weak hash tables (I remember one
in the CLOS department somehwere), and they would be somewhat tested.
Don't remember if we have unit tests for them.