Re: Collecting markers with MPS

[Gerd Möllmann]

Helmut Eller <eller.helmut@gmail.com> writes:

> On Wed, Apr 24 2024, Eli Zaretskii wrote:
>
>>> Yes, but only the programmers know which markers they no longer need.
>>
>> Sorry, I don't follow: how does the old GC detect dead markers?
>
> I don't know the details. You'd have to read the code.  It's wizard
> level.

Not really. In the mark phase, process everything except what's weak.
When that is done, we know what's referenced non-weak, and can process
the weak pqrts. Everything that is marked now is referenced strongly.
Plus some minor details with interdependencies between objects
containing weak references.

>> Why cannot a function we write do the same?
>
> Because we would probably have to scan the heap for all potentially live
> objects.

Yup. The complete mark-phase of the old GC. That's would be very
expensive.