Bug#871608: linux-image-4.9.0-3-amd64: Linux kernel should handle decreasing cpu steal clock counter gracefully

[Hans van Kranenburg <hans.van.kranenburg@mendix.com>]

Hi,

I ran into the same issue with 4.9.51-1 in the guest. My dom0 in this
case is still Jessie with its xen 4.4 version. Users (rightfully) worry
about what's suddenly wrong with their virtual machine, since the steal
values mess up the cpu graphs.

I see that all the discussions linked above have gone silent quickly
without a solution.

A post to the Xen mailing list on Aug 31th did not get any answer yet:
https://lists.xen.org/archives/html/xen-users/2017-08/msg00092.html

I see that the issue got fixed by replacing the code with a new
implementation of the same functionality. I guess this is a scenario
that sometimes happens, not having a ready to go fix available for the
previous LTS kernel.

So, what would be the best step forward here? Should we poke the Xen
people a bit more to find out how to approach this, or get an opinion on
the best and smallest patch to go with?

I'm not an expert in the cpu time accounting area, but I can help
testing etc...

Thanks,

--
Hans van Kranenburg