Re: sbrk

On Sat, Nov 25, 2023 at 08:47:45PM -0700, Warner Losh wrote:
> On Sat, Nov 25, 2023, 8:44 PM <joseph@josephholsten.com> wrote:
> 
> > Yes, it’s no longer included. It’s long been deprecated, but that does
> > make porting things like the original vi a bit challenging.
> >
> > Is there a particular project you’re trying to use it for?
> >
> 
> It was never included in FreeBSD/arm64 due to the fact that the address
> space is complicated now and there no longer is an area beyond bss that you
> can expand into... let alone contract...
> 
> Emacs was not happy with it...

I do not believe there are material differences in handling of user VA
between amd64 and arm64 from the application point of view. Also, I
believe that removal of sbrk(2) from arm64 was more an experiment to see
what breaks, instead of failed attempt to implement it.

Now I think that we should claim that the experiment failed and just
allow sbrk on all Tier 1 arches.  It is not worth the trouble.