Huge instability and insanely large memory footprint in 9.04

John Moser john.r.moser at
Fri Sep 25 13:08:45 UTC 2009

On Fri, Sep 18, 2009 at 7:46 AM, J. Lennard <lennard90 at> wrote:
> Hi list,
> First I'm sorry to write what may appear as a rant, but I hope it is not considered so. I'm writing to express huge instability problems in Ubuntu 9.04. I migrated from ubuntu 8.04 (386) to ubuntu 9.04 (amd64) using a simple clean install.

Mine freezes and eats a massive load of memory on x86-64.  I use
'elevator=as' on the command line; something other than the I/O
scheduler is broken, and CFQ triggers it MUCH more frequently (hours,
sometimes minutes instead of DAYS) than anticipatory.

Some freezes come back; some don't; the ones that come back can be
triggered by hitting NumLock (sends a specific interrupt?  Sysrq sends
INT6, numlock should at most trigger a software driver internal state
change...).  Killing everything (MagicSys E) causes the disk to
suddenly thrash, as whatever blocked path suddenly becomes free.  This
all indicates to me that somewhere exists a racey deadlock in the I/O
system that can affect two or more processes, and that the schedulers
each fault through that path.

It's a kernel issue, I've raised it but let's see if 9.10 fixes the
problem.  I haven't been watching the kernel bug fix list.

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