From: Maxime Devos <maximedevos@telenet.be>
To: Jonas Hahnfeld <hahnjo@hahnjo.de>, guile-devel@gnu.org
Subject: Re: GC + Java finalization
Date: Sat, 03 Jul 2021 19:14:45 +0200 [thread overview]
Message-ID: <ebd60b072db9b040dbb393e0b5aca2aee106187c.camel@telenet.be> (raw)
In-Reply-To: <b775d248390a58e9fbd531cec4ed1bbfb2cfd102.camel@hahnjo.de>
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Jonas Hahnfeld via Developers list for Guile, the GNU extensibility library schreef op za 03-07-2021 om 14:05 [+0200]:
> Hi Guile devs,
>
Hi, I'm not really a Guile dev but I'll respond anyway.
> I'm hacking on GNU LilyPond and recently wondered if Guile could run
> without Java finalization that prevents collection of chains of
> unreachable objects.
Do you have an example where this is a problem?
I.e., did you encounter ‘chains of unreachable objects’ that were
uncollectable, and so, where?
> I found that the functionality is only needed once
> the first guardian is created, so it's possible to delay enabling the
> mode until then. This required some fixes to free functions that
> assumed dependent objects to be freed only later (see first two
> patches).
> The third patch delays ensuring Java finalization to scm_make_guardian,
> but doesn't disable it explicitly (it's on by default in bdwgc). This
> could now be done right after GC_INIT(), but it's not clear (at least
> to me) whether client applications actually rely it, so I think it's
> better if that's not done in Guile itself.
>
> Please consider applying, the fixes potentially also to stable-2.2.
>
> Thanks
> Jonas
I would need to look more closely at how ‘Java-style’ finalisation
works. Some comments anyway:
(first patch)
> * test-suite/standalone/test-smob-mark.c
> (init_smob_type): Correct size of smob type.
> (free_x): Clear smob data instead of local variable.
> (test_scm_smob_mark): Put smobs in array to ensure marking.
>
> - fprintf (stderr, "FAIL: SMOB mark function called for each SMOB\n");
> + // Print pointer so it cannot be collected before.
> + fprintf (stderr, "FAIL: SMOB mark function called for each SMOB (smobs = %p)\n", smobs);
> exit (EXIT_FAILURE);
Normally scm_remember_upto_here is used for that.
Also, I believe "/* */"-style comments are used customarily used in Guile
instead of "//"-style comments.
> static void
> init_smob_type ()
> {
> - x_tag = scm_make_smob_type ("x", sizeof (x_t));
> + x_tag = scm_make_smob_type ("x", sizeof (x_t *));
This change seems to be a fix independent of the ‘do we want Java-style finalization’
question.
(third patch)
Note that guardians are used in (ice-9 popen).
They are also used by some guile libraries (e.g. guile-fibers),
so you can't use (ice-9 popen) or any library using guardians
if Java-style finalization is undesirable.
Greetings,
Maxime.
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next prev parent reply other threads:[~2021-07-03 17:14 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-03 12:05 GC + Java finalization Jonas Hahnfeld via Developers list for Guile, the GNU extensibility library
2021-07-03 17:14 ` Maxime Devos [this message]
2021-07-03 17:26 ` Jonas Hahnfeld via Developers list for Guile, the GNU extensibility library
2021-07-03 18:49 ` Maxime Devos
2021-07-03 18:54 ` Maxime Devos
2021-07-15 18:44 ` Jonas Hahnfeld via Developers list for Guile, the GNU extensibility library
2021-10-10 16:22 ` Jonas Hahnfeld via Developers list for Guile, the GNU extensibility library
2021-11-19 12:18 ` Jonas Hahnfeld via Developers list for Guile, the GNU extensibility library
2022-02-22 10:14 ` Dr. Arne Babenhauserheide
2022-02-22 15:12 ` Mike Gran
2021-11-19 13:13 ` Maxime Devos
2021-11-19 13:32 ` Jonas Hahnfeld via Developers list for Guile, the GNU extensibility library
2021-11-19 13:35 ` Maxime Devos
2021-11-19 13:40 ` Jonas Hahnfeld via Developers list for Guile, the GNU extensibility library
2021-11-19 13:44 ` Maxime Devos
2021-11-19 13:53 ` Maxime Devos
2021-11-19 13:53 ` Jonas Hahnfeld via Developers list for Guile, the GNU extensibility library
2021-11-19 14:01 ` Maxime Devos
2021-11-19 13:48 ` Maxime Devos
2021-11-19 13:55 ` Jonas Hahnfeld via Developers list for Guile, the GNU extensibility library
2021-11-19 14:14 ` Maxime Devos
2021-11-19 14:52 ` Jonas Hahnfeld via Developers list for Guile, the GNU extensibility library
2021-11-19 18:48 ` Maxime Devos
2021-11-19 19:01 ` Jonas Hahnfeld via Developers list for Guile, the GNU extensibility library
2021-11-19 13:15 ` Maxime Devos
2021-11-19 13:35 ` Jonas Hahnfeld via Developers list for Guile, the GNU extensibility library
2021-11-19 14:21 ` Maxime Devos
2021-11-19 15:32 ` Jonas Hahnfeld via Developers list for Guile, the GNU extensibility library
2021-11-19 13:17 ` Maxime Devos
2021-11-19 13:38 ` Jonas Hahnfeld via Developers list for Guile, the GNU extensibility library
2021-11-20 9:19 ` Maxime Devos
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