Re: Memory again

[Eli Zaretskii <eliz@gnu.org>]

> Date: Sat, 26 Nov 2011 20:02:27 +0100
> From: Carsten Mattner <carstenmattner@googlemail.com>
> Cc: antipov@mvista.com, emacs-devel@gnu.org
> 
> On Sat, Nov 26, 2011 at 5:23 PM, Eli Zaretskii <eliz@gnu.org> wrote:
> >> Date: Sat, 26 Nov 2011 15:58:49 +0100
> >> From: Carsten Mattner <carstenmattner@googlemail.com>
> >> Cc: emacs-devel@gnu.org
> >>
> >> Does emacs fear the memory may be used by someone else
> >> and hold onto what it claimed?
> >
> > It doesn't, or at least shouldn't.  When enough memory has been
> > reclaimed by GC, it should give it away to the system.  At least on
> > some systems, I actually see that in action, after killing a large
> > buffer.
> 
> As it's at 56.1megs at the moment after having left it open
> for a couple more hours, I guess that Dmitry's heap fragmentation
> explanation sounds most likely.

If you start a fresh Emacs and visit a very large file, do you see the
footprint increase by approximately that file's size?  And if you then
kill the buffer visiting the file, do you see the footprint go down
back to almost what it was after startup?

> I'd like to not guess but help find potential issues which
> can be corrected.
> 
> How can I instrument/help find leaks or errors in the memory
> manager?

I'd start by showing the value returned by `garbage-collect' and
comparing it with the value after startup.