Messages in this thread | | | Date | Wed, 13 Aug 2003 16:36:38 +0100 | From | Nuno Silva <> | Subject | Re: High CPU load with kswapd and heavy disk I/O |
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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 > - > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ >
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