From: Nuno Silva <nuno.silva@vgertech.com>
To: Ken Savage <kens1835@shaw.ca>
Cc: linux-kernel@vger.kernel.org
Subject: Re: High CPU load with kswapd and heavy disk I/O
Date: Wed, 13 Aug 2003 16:36:38 +0100 [thread overview]
Message-ID: <3F3A5B06.7050103@vgertech.com> (raw)
In-Reply-To: <200308121714.36993.kens1835@shaw.ca>
Hi!
Ken Savage wrote:
> On Tue August 12 2003 16:49, Nuno Silva wrote:
>
>
>>My guess is that this is the cause. LOWMEM pressure because of very
>>large directories... Relating to this, linux-2.6.0-test3-mm1 has Ingo's
>>4G/4G memory split. Can you try this kernel, enable 4G/4G feature, and
>>report back?
>
>
> Something about the 2.6 (and the rmap patched 2.4) kernels causes
> lockouts on the server -- for reasons OTHER than kswapd. The server
If you want to help, you could try to gather more info on that to help
develope a better 2.6 ;)
FWIW, 2.6.0-test* with mm patches works well here... At least in a few
boxes.
> running the delete-old-files process runs hundreds of other CPU and disk
> I/O intensive processes/threads, and it doesn't look like 2.6 is yet able
> to handle the load. Unfortunately, the server is a production environment
> machine at a remote site, so lockouts/reboots/kernel panics are baaaad :(
>
> I've seen other mentions of kswapd/kupdated problems in 2.4.xx, but
> few mentions of solutions. Have people just learned to avoid the
> situations that trigger the mad thrashes?
>
If you're sure that it's really kswapd you can send SIGSTOP and SIGCONT
to kswapd's pid. Kswapd will honor those signals.
killall -STOP kswapd
<run your I/O intensive scripts>
killall -CONT kswapd
Sometimes I do this... For me it works well. If this makes your machine
crash or loose data, don't blame me! ;)
Regards,
Nuno Silva
> Ken
> -
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next prev parent reply other threads:[~2003-08-13 15:36 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-08-12 18:36 High CPU load with kswapd and heavy disk I/O Ken Savage
2003-08-12 19:44 ` Nuno Silva
2003-08-12 20:23 ` Ken Savage
2003-08-12 23:49 ` Nuno Silva
2003-08-13 0:14 ` Ken Savage
2003-08-13 15:36 ` Nuno Silva [this message]
2003-08-13 15:34 HABBINGA,ERIK (HP-Loveland,ex1)
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