Re: Helping with MPS

[Helmut Eller]

On Tue, Aug 20 2024, Pip Cet wrote:

> My current workaround is to have a flag for each signal, plus a global
> flag, and set them when the signal arrives at an inopportune time. We
> check them when we know we just left MPS code, and that part usually
> works, but sometimes we miss the exit, and then we have to wait until
> the next 'maybe_quit' to handle the signal, and that strikes me as
> potentially too long a delay.
>
> So, if you're using GNU/Linux machines, you might run into crashes we
> already know about.  I can provide a temporary fix, but it doesn't feel
> quite good enough for scratch/igc yet.
>
> Any comments or advice would be welcome, of course.

What would you think about creating fork of MPS (on GitHub)
that includes:

a) fixes for known problems:
   https://github.com/Ravenbrook/mps/issues/285
   https://github.com/Ravenbrook/mps/pull/257
   https://github.com/Ravenbrook/mps/pull/38
   https://github.com/Ravenbrook/mps/pull/83

b) removes the instruction emulation on protection faults in the AWL
   pool.  For us, this adds a lot of complexity with questionable gains:
   The weak hash tables implementation is, well, complicated and for the
   marker-vector it's ineffective because there we use tagged pointers
   (apparently without problems).

c) blocks signals. Not my preferred solution, but some people seem to
   think that that is the emacsy way to do things.

?