Messages in this thread | | | Date | Wed, 19 Dec 2012 23:24:00 +0100 | From | Zlatko Calusic <> | Subject | Re: kswapd craziness in 3.7 |
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On 11.12.2012 01:19, Zlatko Calusic wrote: >> On 10.12.2012 20:13, Linus Torvalds wrote: >>> >>> It's worth giving this as much testing as is at all possible, but at >>> the same time I really don't think I can delay 3.7 any more without >>> messing up the holiday season too much. So unless something obvious >>> pops up, I will do the release tonight. So testing will be minimal - >>> but it's not like we haven't gone back-and-forth on this several times >>> already, and we revert to *mostly* the same old state as 3.6 anyway, >>> so it should be fairly safe. >>> > > So, here's what I found. In short: close, but no cigar! > > Kswapd is certainly no more CPU pig, and memory seems to be utilized > properly (the kernel still likes to keep 400MB free, somebody else can > confirm if that's to be expected on a 4GB THP-enabled machine). So it > looks very decent, and much better than anything I run in last 10 days, > barring !THP kernel. > > What remains a mystery is that kswapd occassionaly still likes to get > stuck in a D state, only now it recovers faster than before (sometimes > in a matter of seconds, but sometimes it takes a few minutes). Now, I > admit it's a small, maybe even cosmetic issue. But, it could also be a > warning sign of a bigger problem that will reveal itself on a more > loaded machine. >
Ha, I nailed it!
The cigar aka the explanation together with a patch will follow shortly in a separate topic.
It's a genuine bug that has been with us for a long long time. -- Zlatko
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