[dm-devel] Page Allocation Failures/OOM with dm-crypt on software RAID10 (Intel Rapid Storage)

[Matthias Dahl]

Hello Michal,

many thanks for all your time and help on this issue. It is very much
appreciated and I hope we can track this down somehow.

On 2016-07-13 14:18, Michal Hocko wrote:

> So it seems we are accumulating bios and 256B objects. Buffer heads as
> well but so much. Having over 4G worth of bios sounds really 
> suspicious.
> Note that they pin pages to be written so this might be consuming the
> rest of the unaccounted memory! So the main question is why those bios
> do not get dispatched or finished.

Ok. It is the Block IOs that do not get completed. I do get it right
that those bio-3 are already the encrypted data that should be written
out but do not for some reason? I tried to figure this out myself but
couldn't find anything -- what does the number "-3" state? It is the
position in some chain or has it a different meaning?

Do you think a trace like you mentioned would help shed some more light
on this? Or would you recommend something else?

I have also cc' Mike Snitzer who commented on this issue before, maybe
he can see some pattern here as well. Pity that Neil Brown is no longer
available as I think this is also somehow related to it being a Intel
Rapid Storage RAID10... since it is the only way I can reproduce it. :(

Thanks,
Matthias

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Dipl.-Inf. (FH) Matthias Dahl | Software Engineer | binary-island.eu
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