Re: kswapd0: excessive CPU usage

From: Zdenek Kabelac
Date: Mon Nov 12 2012 - 08:13:24 EST


Dne 12.11.2012 13:19, Mel Gorman napsal(a):
On Sun, Nov 11, 2012 at 10:13:14AM +0100, Zdenek Kabelac wrote:
Hmm, so it's just took longer to hit the problem and observe kswapd0
spinning on my CPU again - it's not as endless like before - but
still it easily eats minutes - it helps to turn off Firefox or TB
(memory hungry apps) so kswapd0 stops soon - and restart those apps
again.
(And I still have like >1GB of cached memory)


I posted a "safe" patch that I believe explains why you are seeing what
you are seeing. It does mean that there will still be some stalls due to
THP because kswapd is not helping and it's avoiding the problem rather
than trying to deal with it.

Hence, I'm also going to post this patch even though I have not tested
it myself. If you find it fixes the problem then it would be a
preferable patch to the revert. It still is the case that the
balance_pgdat() logic is in sort need of a rethink as it's pretty
twisted right now.



Should I apply them all together for 3.7-rc5 ?

1) https://lkml.org/lkml/2012/11/5/308
2) https://lkml.org/lkml/2012/11/12/113
3) https://lkml.org/lkml/2012/11/12/151

Zdenek

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