From: Daniel Colascione <dancol@dancol.org>
To: Pip Cet <pipcet@gmail.com>, Eli Zaretskii <eliz@gnu.org>
Cc: emacs-devel@gnu.org
Subject: Re: Failing to GC killed buffers considered harmful
Date: Sun, 29 Mar 2020 12:12:09 -0700 [thread overview]
Message-ID: <65b0b33a-a85b-e294-6a75-2419552cdbff@dancol.org> (raw)
In-Reply-To: <CAOqdjBcXy=EErkkspU8=BshzktpYpFCaJ72AJWAbf3gJWGGJpQ@mail.gmail.com>
On 3/29/20 12:07 PM, Pip Cet wrote:
> On Sun, Mar 29, 2020 at 6:48 PM Eli Zaretskii <eliz@gnu.org> wrote:
>>> From: Pip Cet <pipcet@gmail.com>
>>> Date: Sun, 29 Mar 2020 16:46:03 +0000
>>> Cc: Daniel Colascione <dancol@dancol.org>, emacs-devel@gnu.org
>>>
>>>> We could, of course, remove the assertion, but then we are left with a
>>>> dead buffer that will never be GC'ed, AFAIU, because objects that come
>>>> from the portable dump are considered constantly marked.
>>>
>>> The same is true of all other objects, though, right?
>>
>> You mean, that they are considered marked? Yes.
>
> Well, if my initial experiments are correct, we correctly remove the
> killed buffer from the all_buffers list; we simply fail to free the
> memory it occupied. That seems like an acceptable loss to me.
>
>>> It seems like it's simply a bad assert to me.
>>
>> Which one?
>
> The one in buffer.c:
>
> /* Only buffers with allocated buffer text should be present at
> this point in temacs. */
> FOR_EACH_BUFFER (b)
> {
> eassert (b->text->beg != NULL);
> }
>
>>> The problem appears to be that "all_buffers" points to a killed
>>> buffer, and is remembered by pdumper.
>>
>> Yes, because pdumper dumps all the Lisp objects present at that point,
>> after performing GC. What else can it do?
>
> My understanding is that pdumper only dumps Lisp objects reachable
> from the heap (not the stack). Buffers are an exception only because
> of all_buffers, which we could rebuild from the dumped buffers.
>
> The call to garbage_collect in Fdump_emacs_portable doesn't actually
> reduce image size.
It runs finalizers, which can free additional memory.
next prev parent reply other threads:[~2020-03-29 19:12 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-29 14:23 Failing to GC killed buffers considered harmful Eli Zaretskii
2020-03-29 16:45 ` Stefan Monnier
2020-03-29 18:54 ` Eli Zaretskii
2020-03-29 19:06 ` Daniel Colascione
2020-03-29 19:24 ` Eli Zaretskii
2020-03-29 16:46 ` Pip Cet
2020-03-29 18:48 ` Eli Zaretskii
2020-03-29 19:07 ` Pip Cet
2020-03-29 19:12 ` Daniel Colascione [this message]
2020-03-29 19:25 ` Pip Cet
2020-03-29 19:28 ` Eli Zaretskii
2020-03-30 15:36 ` Pip Cet
2020-03-30 15:53 ` dancol
2020-03-30 17:07 ` Stefan Monnier
2020-03-30 17:02 ` Stefan Monnier
2020-03-30 18:32 ` Stefan Monnier
2020-03-30 18:51 ` Eli Zaretskii
2020-03-30 19:14 ` Daniel Colascione
2020-03-30 19:40 ` Stefan Monnier
2020-03-31 14:07 ` Eli Zaretskii
2020-03-31 14:09 ` Eli Zaretskii
2020-03-31 21:57 ` Stefan Monnier
2020-03-31 14:58 ` Pip Cet
2020-03-31 16:52 ` Stefan Monnier
2020-03-31 18:23 ` Pip Cet
2020-03-31 19:20 ` Stefan Monnier
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