GNU bug report logs - #66020
[PATCH] Reduce GC churn in read_process_output

Previous Next

Full log

Message #19 received at 66020 <at> debbugs.gnu.org (full text, mbox):

From: Stefan Monnier <monnier <at> iro.umontreal.ca>
To: Dmitry Gutov <dmitry <at> gutov.dev>
Cc: Eli Zaretskii <eliz <at> gnu.org>, Stefan Kangas <stefankangas <at> gmail.com>,
 66020 <at> debbugs.gnu.org
Subject: Re: bug#66020 (bug#64735 spin-off): regarding the default for
 read-process-output-max
Date: Wed, 20 Sep 2023 22:36:18 -0400

> make_process), although I had to use a value produced by make_uninit_string:
> apparently simply storing a char* field inside a managed structure creates
> problems for the GC and early segfaults. Anyway, the result was slightly

That should depend on *where* you put that field.  Basically, it has to
come after:

    /* The thread a process is linked to, or nil for any thread.  */
    Lisp_Object thread;
    /* After this point, there are no Lisp_Objects.  */

since all the words up to that point will be traced by the GC (and
assumed to be Lisp_Object fields).  But of course, if you created the
buffer with `make_uninit_string` then it'll be inside the Lisp heap and
so it'll be reclaimed if the GC doesn't find any reference to it.


        Stefan

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.