Re: [4.7.0rc6] Page Allocation Failures with dm-crypt

From	Mike Snitzer <snitzer@redhat.com>
Newsgroups	linux.kernel
Subject	Re: [4.7.0rc6] Page Allocation Failures with dm-crypt
Date	2016-07-11 15:50 +0200
Message-ID	<rTJKW-7HY-15@gated-at.bofh.it> (permalink)
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On Mon, Jul 11 2016 at  9:27am -0400,
Matthias Dahl <ml_linux-kernel@binary-island.eu> wrote:

> Hello Mike...
> 
> On 2016-07-11 15:18, Mike Snitzer wrote:
> 
> >Something must explain the execessive nature of your leak but
> >it isn't a known issue.
> 
> Since I am currently setting up the new machine, all tests were
> performed w/ various live cd images (Fedora Rawhide, Gentoo, ...)
> and I saw the exact same behavior everywhere.
> 
> >Have you tried running with kmemleak enabled?
> 
> I would have to check if that is enabled on the live images but even if
> it is, how would that work? The default interval is 10min. If I fire up
> a dd, the memory is full within two seconds or so... and after that, the
> OOM killer kicks in and all hell breaks loose unfortunately.

You can control when kmemleak scans.  See Documentation/kmemleak.txt

You could manually trigger a scan just after the dd is started.

But I doubt the livecds have kmemleak compiled into their kernels.

> I don't think this is a particular unique issue on my side. You could,
> if I am right, easily try a Fedora Rawhide image and reproduce it there
> yourself. The only unique point here is my RAID10 which is a Intel Rapid
> Storage s/w RAID. I have no clue if this could indeed cause such a "bug"
> and how.

What is your raid10's full stripesize?  Is your dd IO size of 512K
somehow triggering excess R-M-W cycles which is exacerbating the
problem?

Thread

Re: [4.7.0rc6] Page Allocation Failures with dm-crypt Matthias Dahl <ml_linux-kernel@binary-island.eu> - 2016-07-11 10:40 +0200
  Re: [4.7.0rc6] Page Allocation Failures with dm-crypt Mike Snitzer <snitzer@redhat.com> - 2016-07-11 15:20 +0200
    Re: [dm-devel] [4.7.0rc6] Page Allocation Failures with dm-crypt Matthias Dahl <ml_linux-kernel@binary-island.eu> - 2016-07-11 15:30 +0200
      Re: [4.7.0rc6] Page Allocation Failures with dm-crypt Mike Snitzer <snitzer@redhat.com> - 2016-07-11 15:50 +0200
    Re: [4.7.0rc6] Page Allocation Failures with dm-crypt Mike Snitzer <snitzer@redhat.com> - 2016-07-11 15:40 +0200
      Re: [dm-devel] [4.7.0rc6] Page Allocation Failures with dm-crypt Matthias Dahl <ml_linux-kernel@binary-island.eu> - 2016-07-11 16:50 +0200
        Re: [dm-devel] [4.7.0rc6] Page Allocation Failures with dm-crypt Matthias Dahl <ml_linux-kernel@binary-island.eu> - 2016-07-12 10:10 +0200

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