Re: [RFC PATCH 12/12] housekeeping: Reimplement isolcpus on housekeeping

[Christopher Lameter]

On Mon, 28 Aug 2017, Peter Zijlstra wrote:

> > I think that change is good maybe even a bugfix. I had some people be very
> > surprised when they set affinities to multiple cpus and the processeds
> > kept sticking to one cpu because of isolcpus.
>
> Those people cannot read. And no its not a bug fix. Its documented and
> intended behaviour.

Well the next step was to create a cgroup with those processors and
suddenly load balancing worked again.

This is all pretty confusing stuff. I would rather get rid of isolcpus and
rely on the process affinities set to a single processor, and the removal
of the this processor from all other processes as a sufficient.

I think this already does the right thing. What is mentioned in the isolcpus
documentation is a worry about "suboptimal scheduler performance".

Could we address that issue (if it is still there) and then get rid of
isolcpus?