bug#45200: [PATCH] Force Glibc to free the memory freed

[Eli Zaretskii]

> From: DJ Delorie <dj@redhat.com>
> Cc: hi-angel@yandex.ru, rudalics@gmx.at, monnier@iro.umontreal.ca,
>         carlos@redhat.com, fweimer@redhat.com, 45200@debbugs.gnu.org
> Date: Wed, 03 Feb 2021 14:25:15 -0500
> 
> You (emacs devs) need to decide whether you care more about memory
> footprint or memory performance, and tune malloc accordingly.
> malloc_trim() is one knob to tune, there are others.

Which other knobs are there that aren't deprecated and could disappear
without a warning, though?  We used to use some knobs in the past,
then one day we were told we should stop because those knobs will no
longer be available.

We still use some knobs (see alloc.c), but could some of you please
review that and see if the optimizations we attempt through those
knobs are reasonable?