How to debug out of memory situation?

[Kai Großjohann]

When using Gnus from CVS (I mean the CVS at gnus.org) together with
Emacs from CVS, and I tell the Agent to fetch articles, then I often
get an out of memory error.

At one point, I was actually thrown into the (Lisp-level) debugger,
and at that point I did M-x apropos-value RET ^.\{10000\} RET (also
the same without backslashes), but that didn't find anything.

Is there a way for me to figure out where the memory is gone, so that
Emacs has no more memory?

Hm.  Maybe I should have said M-x apropos-value RET \`\(.\| C-q C-j
\)\{10000\} RET.

Most of the time, Emacs doesn't go into the debugger.  Instead, it
beeps endlessly.  Sometimes, it prints a warning about memory full
and advises me to save buffers and kill Emacs.  Sometimes it gives me
a memory-full warning and asks me whether to continue.  I think both
answers (yes, and no) result in endless beeps...
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