bug#42482: closed (27.0.91; emacs modules memory leak)

[GNU bug Tracking System]

Your message dated Thu, 23 Jul 2020 14:06:57 +0200
with message-id 
<CAArVCkQHSYWscek=GPhwixCmy8jg4fk3y-ZYxRkWcY9HbAzJBw@mail.gmail.com>
and subject line Re: bug#42482: 27.0.91; emacs modules memory leak
has caused the debbugs.gnu.org bug report #42482,
regarding 27.0.91; emacs modules memory leak
to be marked as done.

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42482: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=42482
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--- Begin Message --- Subject: 27.0.91; emacs modules memory leak Date: Wed, 22 Jul 2020 19:25:19 -0400

env-make_global_ref adds a reference to the underlying Lisp_Object
and allocates emacs_value from the global storage. env->free_global_ref
on the other hand will only remove a reference to the underlying
Lisp_Object and not free the emacs_value.

Here is a simple recipe to reproduce the problem (I only tested this
on linux). I'm attaching the necessary files.

$ gcc -shared -fpic -std=c99 -I <dir-with-emacs-module.h>
create_global_refs.c -o create_global_refs.so
$ emacs --no-splash -q -l create_global_refs.so -l create_global_refs_test.el

If you look at the memory usage of emacs (for example in htop) you'll
see that with emacs-26 it is constant but with emacs-27 the resident
memory quickly grows.

create_global_refs.c
Description: Text Data

create_global_refs_test.el
Description: Text Data

--- End Message ---

> --- Begin Message ---
>
>
>
> Subject: 
>
> Re: bug#42482: 27.0.91; emacs modules memory leak
>
>
>
>
> Date: 
>
> Thu, 23 Jul 2020 14:06:57 +0200
>
>
>
>
> Am Do., 23. Juli 2020 um 01:27 Uhr schrieb Milan Stanojević
> <mstanojevic@janestreet.com>:
> >
> > env-make_global_ref adds a reference to the underlying Lisp_Object
> > and allocates emacs_value from the global storage. env->free_global_ref
> > on the other hand will only remove a reference to the underlying
> > Lisp_Object and not free the emacs_value.
> >
> > Here is a simple recipe to reproduce the problem (I only tested this
> > on linux). I'm attaching the necessary files.
> >
> > $ gcc -shared -fpic -std=c99 -I <dir-with-emacs-module.h>
> > create_global_refs.c -o create_global_refs.so
> > $ emacs --no-splash -q -l create_global_refs.so -l create_global_refs_test.el
> >
> > If you look at the memory usage of emacs (for example in htop) you'll
> > see that with emacs-26 it is constant but with emacs-27 the resident
> > memory quickly grows.
>
> Thanks for the report. I've fixed this in commit
> 5c5eb9790898e4ab10bcbbdb6871947ed3018569; the fix is slightly
> different from what you proposed in that it stores the emacs_value
> object in the global references hashtable, but it should have the same
> effect. At least I can't reproduce the symptom any more after that
> commit.
>
>
> --- End Message ---