Message-ID: <3A7959E9.E62F4581@linux.com>
Date: Thu, 01 Feb 2001 04:43:22 -0800
From: David Ford <david@linux.com>
Organization: Blue Labs Software
MIME-Version: 1.0
To: Ed Tomlinson <tomlins@cam.org>
CC: linux-kernel@vger.kernel.org
Subject: Re: VM brokenness, possibly related to reiserfs
In-Reply-To: <01020107391500.07626@oscar>
Content-Type: text/plain; charset=us-ascii
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Sender: linux-kernel-owner@vger.kernel.org

Correct, the point of the matter is to find stress points.  It will do the exact
same thing when it reaches the end of swap.  I suspect a relation to reiserfs
fighting for buffers perhaps.  This fight occurs a few megs before the OOM
routine trips.

-d

Ed Tomlinson wrote:

> Hi,
>
> Gather this is with no swap space allocated...  And the question is why does
> the oom handler not get triggered?
>
> Ed Tomlinson
>
> David Ford wrote:
>
> > (Chris, changing JOURNAL_MAX_BATCH from 900 to 100 didn't affect
> > anything).
> >
> > Ok, having approached this slightly more intelligently here are [better]
> > results.
> >
> > The dumps are large so they are located at http://stuph.org/VM/.  Here's
> > the story.  I boot and startx, I load xmms and netscape to eat away
> > memory.  When free buffers/cache falls below 7M the system stalls and
> > the only recovery is sysrq-E or reboot.  At the moment of stall the disk
> > will grind continuously for about 25 to 30 minutes then go silent.  At
> > this point in time the only recovery is reboot, sysrq-E won't work.
> >
> > If I move the mouse or type a key within 30 seconds of this incident,
> > that user input will take about 5 minutes to register.  After that
> > initial minute, nothing more will happen.
> >
> > Kernel 2.4.1, with reiserfs, devfs, no patches applied.
> >
> > "klog-X" are basically the same thing but I'm running top, syslogd, and
> > klogd with -20 priority.  I didn't note anything out of the ordinary in
> > top.  These are snapshots where I've managed to murder processes and
> > restart the problem without rebooting.
> >
> > In the second instance, I had my finger on the kill button and managed
> > to kill netscape and recover partially.  However the system was heavily
> > loaded even after the kill.
> >
> > I have xmms in STOPped state so it's just waiting.
> >
> > kswapd is taking 12.2% of the CPU according to ps, and kapm-idled is
> > taking 26.9%.  bdflush is taking 2.7%, X 3.5%, all others are nominal.
> > The system load was hovering at 1.00 for a few minutes then dropped to
> > zero.  However scrolling text in an rxvt is slow enough to watch blocks
> > move.  Running "ps aux" takes nearly one third of a second for total
> > time.  Total number of processes is ~40.
> >
> > Jan 31 22:31:51 nifty kernel: kapm-idled  S CBF77F94  4124     3
> > 1        (L-TLB)       4     2
> > Jan 31 22:31:51 nifty kernel: Call Trace: [schedule_timeout+115/148]
> > [process_timeout+0/72] [apm_mainloop+221/256] [apm+668/692]
> > [kernel_thread+31/56] [kernel_thread+40/56]
> >
> > Jan 31 22:31:51 nifty kernel: kswapd    S CBF75FAC  5704     4
> > 1        (L-TLB)       5     3
> > Jan 31 22:31:51 nifty kernel: Call Trace: [schedule_timeout+115/148]
> > [process_timeout+0/72] [interruptible_sleep_on_timeout+66/92]
> > [kswapd+213/244] [kernel_thread+40/56]
> >
> > Jan 31 22:31:52 nifty kernel: bdflush   S CBF70000  5912     6
> > 1        (L-TLB)       7     5
> > Jan 31 22:31:52 nifty kernel: Call Trace: [bdflush+206/216]
> > [kernel_thread+40/56]
> >
> >
> > In the fourth snapshot, I have put xmms in STOP state again inside the
> > memory shortage, memory is at 4800 free buffers/cache and 1592 free mem.
> >
> > As I entered this shortage period I started a 'ps -eo ... > file' to try
> > and record data there.  This is the only disk activity happening.  Load
> > is ~4.00.  I have now killed the ps.
> >
> > Load has dropped significantly and I have tolerable but quite laggy user
> > input responsiveness now.
> >
> > Memory is currently 4900/1588 like above.  Load is about 2.00 and will
> > continue dropping if I don't do anything.  Any processes I exec which
> > need to be loaded from disk take several seconds.  I.e. 'uptime' takes
> > about 4 seconds to execute.
> >
> > Snapshot #5 will be the last one and I will reboot.  Once memory is
> > freed from xmms (back to 150megs free), everything is peachy.
> >
> >
> > -d
> >
> > --
> >   There is a natural aristocracy among men. The grounds of this are virtue
> and talents.
> >   Thomas Jefferson The good thing about standards is that there are so many
> to choose
> >   from. Andrew S. Tanenbaum
> >
> >
> >
> > -
> > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> > the body of a message to majordomo@vger.kernel.org
> > Please read the FAQ at http://www.tux.org/lkml/
> >

--
  There is a natural aristocracy among men. The grounds of this are virtue and talents. Thomas Jefferson
  The good thing about standards is that there are so many to choose from. Andrew S. Tanenbaum


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