Re: MPS: weak hash tables

["Gerd Möllmann" <gerd.moellmann@gmail.com>]

Pip Cet <pipcet@protonmail.com> writes:

>> We have already this in bignum.c
>> 
>> mp_set_memory_functions (xmalloc, xrealloc_for_gmp, xfree_for_gmp);
>> 
>> Haven't read the GMP docs yet, but that looks like something that could
>> be used.
>
> Patch attached, couldn't resist :-)

Haha :-). I'm all for it!

> Memory usage is perfectly acceptable with this patch, but it does do a
> lot of GC.

What do the timings say?

>> > I believe Eli is right, though, that we should deviate from what Emacs
>> > usually does as little as possible until we've got things working.
>> > That means just keeping track of how much we've allocated and calling
>> > garbage_collect via maybe_garbage_collect, I think.
>
>> Can you explain? I mean I agree in general, but in this case I'm not so
>> sure. What I've currently implemented is basically a function of the
>> number of allocated finalizable objects and only finalizable objects pay
>> the price. The size of allocated memory overall, i.e. counting the bytes
>> in alloc_impl doesn't contain the information.
>
> But it's probably a better indicator of how much GC activity happened,
> and that influences how many finalization messages there would be,
> assuming that an approximately constant percentage of objects is
> finalizable...

Hm. I'm not really convinced the total amount allocated is a better
predictor for how many finalzation msgs we might expect than the real
number of objects for which we might expect finalization messages.

But whatever. Something for later, maybe.