bug#36649: 27.0.50; pure space and pdumper

[Pip Cet]

On Fri, Aug 21, 2020 at 1:47 PM Eli Zaretskii <eliz@gnu.org> wrote:
> > From: Pip Cet <pipcet@gmail.com>
> > Date: Fri, 21 Aug 2020 13:04:47 +0000
> > Cc: 36649@debbugs.gnu.org, Paul Eggert <eggert@cs.ucla.edu>
> >
> > On Fri, Aug 21, 2020 at 12:52 PM Lars Ingebrigtsen <larsi@gnus.org> wrote:
> > > I didn't read this thread closely, but it seems like the conclusion that
> > > this patch should have been applied.  (It removes pure space,
> > > apparently?)
> > >
> > > The patch never was applied, though -- should it be applied now?
> >
> > I believe it's best to be careful with this one. Pure space affects GC
> > in subtle ways, and it also affects performance.
> >
> > See this thread:
> > https://lists.gnu.org/archive/html/emacs-devel/2019-07/msg00588.html
> >
> > I'd be happy to set up a separate branch for removing pure space if
> > that's preferred.
>
> What do we do with unexec builds, which are still supported?

I think that's an important question, but I don't think it's strongly
connected to pure space.

In fact, it appears like unexec builds are currently broken on master,
and on this GNU/Linux machine, I've got to force use of HYBRID_MALLOC
to get an unexec build starting at all. But, having done that, it
works with and without the patch, at first glance.

Rebased patch attached (but I just noticed  the commit message is no
longer complete).

0001-Remove-pure-space.patch
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