From: Eli Zaretskii <eliz@gnu.org>
To: mattiase@acm.org
Cc: emacs-devel@gnu.org
Subject: Re: last_marked array is now ifdef'ed away
Date: Thu, 12 Sep 2024 12:19:20 +0300 [thread overview]
Message-ID: <86ed5pkz53.fsf@gnu.org> (raw)
In-Reply-To: <86zfokyp64.fsf@gnu.org> (message from Eli Zaretskii on Sat, 07 Sep 2024 09:05:07 +0300)
Ping! Mattias, could you please respond?
> Date: Sat, 07 Sep 2024 09:05:07 +0300
> From: Eli Zaretskii <eliz@gnu.org>
> Cc: emacs-devel@gnu.org
>
> Commit 7a8798de95a5 (from Apr 4 2022) made the last_marked[] array and
> the related machinery of tracing the marked objects #ifdef'ed away by
> default:
>
> +/* Whether to remember a few of the last marked values for debugging. */
> +#define GC_REMEMBER_LAST_MARKED 0
> +
> +#if GC_REMEMBER_LAST_MARKED
> enum { LAST_MARKED_SIZE = 1 << 9 }; /* Must be a power of 2. */
> Lisp_Object last_marked[LAST_MARKED_SIZE] EXTERNALLY_VISIBLE;
> static int last_marked_index;
> +#endif
> [...]
> - last_marked[last_marked_index++] = obj;
> - last_marked_index &= LAST_MARKED_SIZE - 1;
> +#if GC_REMEMBER_LAST_MARKED
> + last_marked[last_marked_index++] = obj;
> + last_marked_index &= LAST_MARKED_SIZE - 1;
> +#endif
>
> I don't remember this aspect being discussed, and the commit log
> message doesn't even mention the change, let alone provides a
> rationale for it.
>
> Mattias, why was this done? Are the changes you introduced in that
> changeset somehow incompatible with the last_marked[] facility? If
> not, I think we should make this again compiled-in by default, because
> IME it is a valuable means of debugging GC problems.
>
>
next prev parent reply other threads:[~2024-09-12 9:19 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-09-07 6:05 last_marked array is now ifdef'ed away Eli Zaretskii
2024-09-12 9:19 ` Eli Zaretskii [this message]
2024-09-13 14:43 ` Mattias Engdegård
2024-09-13 15:21 ` Eli Zaretskii
2024-09-14 17:05 ` Mattias Engdegård
2024-09-14 17:30 ` Eli Zaretskii
2024-09-14 20:30 ` Mattias Engdegård
2024-09-15 5:51 ` Eli Zaretskii
2024-09-15 13:58 ` Mattias Engdegård
2024-09-15 14:21 ` Eli Zaretskii
2024-09-17 10:15 ` Mattias Engdegård
2024-09-17 13:22 ` Eli Zaretskii
2024-09-14 22:50 ` Stefan Kangas
2024-09-15 6:01 ` Eli Zaretskii
2024-09-16 18:07 ` Andrea Corallo
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=86ed5pkz53.fsf@gnu.org \
--to=eliz@gnu.org \
--cc=emacs-devel@gnu.org \
--cc=mattiase@acm.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this external index
https://git.savannah.gnu.org/cgit/emacs.git
https://git.savannah.gnu.org/cgit/emacs/org-mode.git
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.