From: Baoqiu Cui <Baoqiu.Cui@yahoo.com>
To: rms@gnu.org
Cc: Robert Widhopf-Fenk <hack@robf.de>, emacs-devel@gnu.org
Subject: Re: VM crashes on big INBOX file ==> problem found!!!
Date: Thu, 20 Dec 2007 14:21:04 -0800 [thread overview]
Message-ID: <18282.60112.186266.318585@AFTERRDOUBT-LX.ds.corp.yahoo.com> (raw)
In-Reply-To: <E1IlmAe-0000BJ-I0@fencepost.gnu.org>
Sorry for the late reply. I wanted to look deeper into the VM code but
could not find time to do that. I guess it might be easier for the new
maintainer of VM, Robert Widhopf-Fenk, to take a look at this problem
and see if there is anything that can be changed in VM. I am copying
this email to Robert...
Thanks for looking into this problem, Richard!
- Baoqiu
Richard Stallman writes:
> garbage collection is triggered and function mark_object() (in alloc.c)
> is recursively called about 29,885 times (see the backtrace info
> below)!!! So many levels of mark_object() calls make the stack
> overflow, causing a segmentation fault.
>
> I wonder if this indicates a bad choice of data structures.
> mark_object calls itself recursively for many kinds of pointers,
> but it is supposed to loop rather than recurse for cdr pointers.
> This is so that long lists do not cause recursion.
> Most data structures don't have a tremendous amount of nesting
> in the car direction.
>
> I wonder what sort of data structures made 29,885 recursive
> calls necessary. Perhaps we should change those data structures
> or else change the garbage collector so it recurses less.
>
> For instance, maybe a lot of this recursion goes thru symbols. If so,
> here is an idea. Suppose that when mark_object finds a symbol which
> is not yet marked, and is interned in the main obarray, it sets a bit
> "needs to be marked" in the symbol. Then increment a counter
> which records how many symbols are in this state.
>
> Then gc_sweep could end by scanning the main obarray over and over,
> marking those symbols, until the counter goes to zero.
>
> Depending on the nature of the problem, this might or might not
> help much. If the main data types involved are others,
> a different solution might help.
next prev parent reply other threads:[~2007-12-20 22:21 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <yoruodet2jjm.fsf@AFTERRDOUBT-LX.ds.corp.yahoo.com>
[not found] ` <fflvjt$dcs$1@reader1.panix.com>
[not found] ` <yoru7ildglb3.fsf@AFTERRDOUBT-LX.ds.corp.yahoo.com>
[not found] ` <ffo8rl$169$1@reader1.panix.com>
[not found] ` <v9myu82p62.fsf@marauder.physik.uni-ulm.de>
[not found] ` <yorumyu8f7pt.fsf@AFTERRDOUBT-LX.ds.corp.yahoo.com>
[not found] ` <yoruabq6icer.fsf_-_@AFTERRDOUBT-LX.ds.corp.yahoo.com>
2007-10-27 13:57 ` VM crashes on big INBOX file ==> problem found!!! Richard Stallman
2007-12-20 22:21 ` Baoqiu Cui [this message]
2007-12-21 19:49 ` Richard Stallman
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
List information: https://www.gnu.org/software/emacs/
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=18282.60112.186266.318585@AFTERRDOUBT-LX.ds.corp.yahoo.com \
--to=baoqiu.cui@yahoo.com \
--cc=emacs-devel@gnu.org \
--cc=hack@robf.de \
--cc=rms@gnu.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 public inbox
https://git.savannah.gnu.org/cgit/emacs.git
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).