From: "Richard B. Johnson" <root@chaos.analogic.com>
To: Andrea Arcangeli <andrea@suse.de>
Cc: Kristian Peters <kristian.peters@korseby.net>,
linux-kernel@vger.kernel.org,
"Robert L. Harris" <Robert.L.Harris@rdlg.net>
Subject: Re: oom killer in 2.4.23
Date: Tue, 9 Dec 2003 09:52:13 -0500 (EST) [thread overview]
Message-ID: <Pine.LNX.4.53.0312090942470.8772@chaos> (raw)
In-Reply-To: <20031209142151.GB12532@dualathlon.random>
On Tue, 9 Dec 2003, Andrea Arcangeli wrote:
> On Sat, Dec 06, 2003 at 10:31:43AM +0100, Kristian Peters wrote:
> > Andrea Arcangeli <andrea@suse.de> schrieb:
> > > what you're complaining is the 'selection of the task to be killed'.
> > > That's not solvable. the kernel can't read your brain period. Only if
> > > the kernel could read the brain of the adminstrator then you would be
> > > happy, there is no way the kernel can know which is the task you really
> > > want to have killed first.
> >
> > I agree. On a server the most likely application to be killed would be the service with the most pages in memory. And those services tend to be the important ones.
> >
> > However, for a simple desktop-linux that statistical approach seems to
> > be wrong. Your vm has even killed /sbin/getty sometimes, so that I
> > can't login via a simple console.
>
Not true! Killing a getty or agetty or any other login
program cannot prevent a login! Init will just start another
one if there is enough RAM to fork()/exec(). If there isn't,
it has nothing to do with killing the getties and everything
to do with being completely out of RAM. In that case, you
need to enable quotas and not let fork-bombs or other deliberate
crashers be executed by root.
Script started on Tue Dec 9 09:42:06 2003
# ps
PID TTY STAT TIME COMMAND
478 3 S 0:00 /sbin/agetty 38400 tty3
479 4 S 0:00 /sbin/agetty 38400 tty4
480 5 S 0:00 /sbin/agetty 38400 tty5
481 6 S 0:00 /sbin/agetty 38400 tty6
4404 1 S 0:00 -bash
6102 2 S 0:00 -bash
8772 1 S 0:00 pine
8778 2 S 0:00 script
8779 2 S 0:00 script
8780 p0 S 0:00 bash -i
8784 p0 R 0:00 ps
# killall -9 agetty
# ps
PID TTY STAT TIME COMMAND
4404 1 S 0:00 -bash
6102 2 S 0:00 -bash
8772 1 S 0:00 pine
8778 2 S 0:00 script
8779 2 S 0:00 script
8780 p0 S 0:00 bash -i
8787 3 S 0:00 /sbin/agetty 38400 tty3
8788 4 S 0:00 /sbin/agetty 38400 tty4
8789 5 S 0:00 /sbin/agetty 38400 tty5
8790 6 S 0:00 /sbin/agetty 38400 tty6
8791 p0 R 0:00 ps
# exit
exit
Script done on Tue Dec 9 09:42:41 2003
The above shows 4 getty's being killed. They are immediately
restarted by init. These getties become new shell-tasks in
the following order: exec /sbin/login, exec /bin/bash. There are
no additional forks so, in principle, you have nearly all the
resources needed for a shell as soon as a getty is started.
Cheers,
Dick Johnson
Penguin : Linux version 2.4.22 on an i686 machine (797.90 BogoMips).
Note 96.31% of all statistics are fiction.
next prev parent reply other threads:[~2003-12-09 14:52 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <Z6Iv-7O2-29@gated-at.bofh.it>
[not found] ` <Z8Ag-3BK-3@gated-at.bofh.it>
[not found] ` <Zbyn-23P-29@gated-at.bofh.it>
2003-12-05 13:05 ` oom killer in 2.4.23 Kristian Peters
2003-12-05 13:56 ` Robert L. Harris
2003-12-05 19:58 ` Andrea Arcangeli
2003-12-06 9:31 ` Kristian Peters
2003-12-09 14:21 ` Andrea Arcangeli
2003-12-09 14:52 ` Richard B. Johnson [this message]
2003-12-09 17:06 ` Andrea Arcangeli
2003-12-09 18:50 ` Kristian Peters
2003-12-05 22:38 ` Mike Fedyk
2003-12-05 22:56 ` Andrea Arcangeli
2003-12-04 16:12 Peter Bergmann
2003-12-04 17:02 ` Maciej Zenczykowski
2003-12-04 17:20 ` Guillermo Menguez Alvarez
2003-12-04 23:52 ` Andrea Arcangeli
2003-12-04 18:33 ` Peter Bergmann
2003-12-04 18:42 ` Jens Axboe
2003-12-04 20:38 ` Peter Bergmann
2003-12-04 20:28 ` Szakacsits Szabolcs
2003-12-04 23:58 ` Andrea Arcangeli
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