From: Stefan Monnier <monnier@IRO.UMontreal.CA>
To: Daniel Colascione <dancol@dancol.org>
Cc: Dmitry Antipov <dmantipov@yandex.ru>, 17168@debbugs.gnu.org
Subject: bug#17168: 24.3.50; Segfault at mark_object
Date: Sun, 06 Apr 2014 15:58:27 -0400 [thread overview]
Message-ID: <jwvha66jl97.fsf-monnier+emacsbugs@gnu.org> (raw)
In-Reply-To: <534176F3.9090205@dancol.org> (Daniel Colascione's message of "Sun, 06 Apr 2014 08:46:59 -0700")
> The pinned bit approach is exactly what I implemented, except that we
> walk obarray, like we already do, instead of all symbols.
We already walk obarray during the mark phase, so I don't understand
what you mean here.
> Your approach would require that we check for non-symbols in purecopy
> and reject them,
Yes.
> and it'd have a bigger performance impact, since we'd
> then need to walk the entire symbol list essentially twice.
Indeed. I don't expect it to be significant, tho. As you point out we
already walk that list once during gc_sweep, so doing it one more time
should be very quick. Also, I'd expect that a significant proportion of
all symbols would be marked with that bit, so scanning all symbols won't
take that much longer than the alternative of only scanning a vector of
pinned symbols. Also scanning all symbols like gc_sweep means that the
scan is nicely sequential in memory.
> I'd strongly prefer the fully general approach in my patch. It isn't
> *that* complicated.
But it requires more memory, whereas we already have space for an extra
bit in the Lisp_Symbol struct. I guess the main difference resides in
whether we want to allow uninterning pinned symbols. If we do as you
suggest and disallow it, then indeed, I expect there to be rather few
uninterned pinned symbols so using a small auxiliary array makes sense.
But I'd rather we don't pay attention to a symbol's interned status, so
we can later unintern them.
Stefan
next prev parent reply other threads:[~2014-04-06 19:58 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-04-02 7:44 bug#17168: 24.3.50; Segfault at mark_object Nicolas Richard
2014-04-02 15:53 ` Daniel Colascione
2014-04-02 17:59 ` Nicolas Richard
2014-04-02 16:29 ` Dmitry Antipov
2014-04-02 19:46 ` Daniel Colascione
2014-04-02 20:33 ` Daniel Colascione
2014-04-02 20:57 ` Nicolas Richard
2014-04-02 21:50 ` Daniel Colascione
2014-04-02 23:24 ` Stefan Monnier
2014-04-03 0:28 ` Daniel Colascione
2014-04-02 20:37 ` Eli Zaretskii
2014-04-02 20:40 ` Daniel Colascione
2014-04-02 20:55 ` Eli Zaretskii
2014-04-03 6:59 ` Dmitry Antipov
2014-04-03 7:04 ` Dmitry Antipov
2014-04-03 7:55 ` Daniel Colascione
2014-04-03 9:08 ` Daniel Colascione
2014-04-03 14:03 ` Dmitry Antipov
2014-04-03 15:42 ` Stefan Monnier
2014-04-03 16:47 ` Daniel Colascione
2014-04-03 17:49 ` Dmitry Antipov
2014-04-03 17:51 ` Daniel Colascione
2014-04-03 19:21 ` Stefan Monnier
2014-04-03 19:22 ` Daniel Colascione
2014-04-05 22:37 ` Daniel Colascione
2014-04-06 5:05 ` Dmitry Antipov
2014-04-06 5:11 ` Daniel Colascione
2014-04-06 18:00 ` Richard Stallman
2014-04-06 18:10 ` Daniel Colascione
2014-04-06 19:06 ` Eli Zaretskii
2014-04-07 7:49 ` martin rudalics
2014-04-07 8:18 ` Dmitry Antipov
2014-04-07 9:20 ` martin rudalics
2014-04-06 12:36 ` Stefan Monnier
2014-04-06 15:06 ` Eli Zaretskii
2014-04-06 15:59 ` Daniel Colascione
2014-04-06 16:19 ` Eli Zaretskii
2014-04-06 16:24 ` Daniel Colascione
2014-04-06 16:29 ` Eli Zaretskii
2014-04-06 16:37 ` Daniel Colascione
2014-04-06 16:59 ` Eli Zaretskii
2014-04-06 17:11 ` Daniel Colascione
2014-04-06 19:44 ` Stefan Monnier
2014-04-06 19:42 ` Stefan Monnier
2014-04-06 15:46 ` Daniel Colascione
2014-04-06 19:58 ` Stefan Monnier [this message]
2014-04-06 20:13 ` Daniel Colascione
2014-04-06 20:53 ` Daniel Colascione
2014-04-06 21:08 ` Stefan Monnier
2014-04-06 21:37 ` Daniel Colascione
2014-04-07 16:28 ` Stefan Monnier
2014-04-07 19:06 ` Daniel Colascione
2014-04-07 20:42 ` Stefan Monnier
2014-04-08 7:14 ` martin rudalics
2014-04-08 8:47 ` Daniel Colascione
2014-04-06 18:01 ` Richard Stallman
2014-04-06 19:58 ` Stefan Monnier
2014-04-07 16:56 ` Richard Stallman
2014-04-02 20:49 ` Nicolas Richard
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