bug#21556: 25.0.50; Memory leak in emacs -Q with lucid (font)

[Eli Zaretskii]

> From: Dima Kogan <dima@secretsauce.net>
> Cc: 21556@debbugs.gnu.org
> Date: Fri, 25 Sep 2015 01:13:15 -0700
> 
> Hi. I just came back to this, figured out how to (semi-manually) put in
> a watchpoint, and this watchpoint told me what's resetting the font
> cache: the garbage collector. The backtrace in question:
> 
>     0x00000000005d2172 in compact_font_cache_entry (entry=24121763) at 
> alloc.c:5313
>     #0  0x00000000005d2172 in compact_font_cache_entry (entry=24121763) at 
> alloc.c:5313
>     #1  0x00000000005d221b in compact_font_caches () at alloc.c:5339
>     #2  0x00000000005d2742 in garbage_collect_1 (end=0x7ffcdb166830) at 
> alloc.c:5515
>     #3  0x00000000005d2e1d in Fgarbage_collect () at alloc.c:5720
>     #4  0x000000000054eb21 in maybe_gc () at lisp.h:4515
>     #5  0x00000000005f638c in Ffuncall (nargs=3, args=0x7ffcdb166988) at 
> eval.c:2584

Yes, that's what I wrote to you you meanwhile.

This seems to mean that fonts whose entries in the cache are not
marked are still being used, or are unused but not freed.