Re: Memory leaks in font objects

[Dmitry Antipov <dmantipov@yandex.ru>]

On 10/24/2013 06:19 PM, Stefan Monnier wrote:

> Oddly enough, I'm not sure it's a leak.  Here's the result of my test:
>
>               VM   RSS
>     initial  204    24
>     after 1  522   290
>     after 2  539   305
>     after 3  542   308
>     after 4  542   308
>
> So it's more like "once malloced, the memory can be reused by Emacs, but
> not by another process because we never return it to the OS".

IIUC no :-(. I tried the following:

initial: 32M RSS
then M-x bloat-font, M-x set-frame-font "fixed", M-x garbage-collect: 372M
then M-x byte-force-recompile [all lisp/ subdir], M-x garbage-collect: 437M

If 372M is (mostly) free but just too fragmented to release, byte-force-recompile
should reuse a lot of memory - so why +65M? But, 2nd run of bloat-font do not add
too much. Why? Consider XLoadQueryFont example. When you do not call XFreeFont but
just lost XFontStruct pointer, the font is still allocated by Xlib. Since you lost
the pointer, you can't use this font unless you call XLoadQueryFont for the same
font again and got the pointer to previously allocated resource (assuming that you
do not lost the connection to X display). So 2nd, 3rd, etc. calls to bloat-font
will just re-use font resources you lost before. But, if you need to allocate
something else, you will need more memory.

> What the difference between "close" and "finalize"?

Nothing except "close" is a part of existing interface which I don't want
to change (at this moment at least), and requires extra frame argument.

Dmitry