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[Arwed von Merkatz <v.merkatz AT gmx.net>]

On Tue, Sep 21, 2004 at 06:43:49PM +0200, Arwed von Merkatz wrote:
> On Mon, Sep 20, 2004 at 08:20:26AM -0700, Eric Sandall wrote:
> > Shall we update util-linux?
> > 
> > -sandalle
> 
> Updated in devel and test.

Just to inform everyone, I downgraded util-linux to 2.12d in devel and
test since umount seems to be broken in 2.12e.

umount worked as root, but as user (with correctly configured fstab) it
just hang with 100% cpu usage, downgrading util-linux fixed it.

> > ----- Forwarded message from Andries.Brouwer AT cwi.nl -----
> >     Date: Mon, 20 Sep 2004 00:05:02 +0200 (MEST)
> >     From: Andries.Brouwer AT cwi.nl
> > Reply-To: Andries.Brouwer AT cwi.nl
> >  Subject: OOM & [OT] util-linux-2.12e
> >       To: linux-kernel AT vger.kernel.org
> > 
> > Just released (on ftp.win.tue.nl in /pub/linux-local/utils/util-linux)
> > util-linux-2.12e.
> > 
> > The reason for this release were complaints that mount and umount
> > OOM the kernel when the number of mounts is large.
> > And indeed - I tried with 30000 mounts and the OOM-killer killed
> > everything in sight, including X's console, making X exit, killing
> > all remaining processes.
> > 
> > The new versions have been polished a little bit so as not to waste
> > too much memory, and now survive the 30000 mount/umount test for me.
> > Further polishing is needed for the case of large numbers of mounts;
> > when /etc/mtab is not a symlink to /proc/mounts then umount -a has
> > quadratic behaviour (it updates mtab after each unmount) and that
> > gets terribly slow.
> > 
> > About OOM: I am still of the opinion that the default state of the
> > kernel must be one where OOM does not occur and malloc() tells us
> > that we are out of memory. A system that suddenly decides to kill
> > all processes is really very poor and unreliable.
> > Users can enable other behaviours if they don't care about reliability.
> > 
> > About mount: I wondered whether I should rewrite [u]mounts's handling
> > of /etc/mtab so as to be a bit faster. But it seems a waste of time -
> > /proc/mounts has many advantages: automatically up-to-date, correct
> > also when namespaces are used, much faster. On the other hand, /etc/mtab
> > contains mount options that are sometimes needed later.
> > If it were possible to store the mount options in the kernel, making
> > them visible in /proc/mounts, then we could forget /etc/mtab altogether.
> > 
> > People have asked repeatedly for a way to mark lines in /etc/fstab
> > so as to make clear that such lines are managed by some GUI or other
> > external program. Labels like "kudzu".
> > In this release I added a comment convention for /etc/fstab: options
> > can have a part starting with \; - that part is ignored by mount
> > but can be used by other programs managing fstab.
> > 
> > If we would put the mount options in /proc/mounts, and introduced
> > a comment convention (say, the part starting with \: is ignored by
> > the kernel but can be used by programs reading /proc/mounts),
> > then /etc/mtab can die. Comments? Better solutions?
> > 
> > About util-linux and stuff: I have maintained various packages
> > for ten years or so - it may be time to pass things on to someone else.
> > Write to aeb AT cwi.nl if you are interested in taking over or
> > co-maintaining kbd or man or man-pages or util-linux.
> > 
> > Andries
> > -
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> > Please read the FAQ at  http://www.tux.org/lkml/
> > 
> > ----- End forwarded message -----
> > 
> > 
> > --
> > Eric Sandall                     |  Source Mage GNU/Linux Developer
> > eric AT sandall.us PGP: 0xA8EFDD61  |  http://www.sourcemage.org/
> > http://eric.sandall.us/          |  SysAdmin @ Inst. Shock Physics @ WSU
> > http://counter.li.org/  #196285  |  http://www.shock.wsu.edu/
> > 
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> 
> -- 
> Arwed v. Merkatz                              Source Mage GNU/Linux 
> developer
>                                                     
> http://www.sourcemage.org
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-- 
Arwed v. Merkatz                              Source Mage GNU/Linux developer
                                                    http://www.sourcemage.org