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

[Peter Zijlstra]

On Wed, Aug 23, 2017 at 09:55:51AM -0500, Christopher Lameter wrote:
> On Wed, 23 Aug 2017, Frederic Weisbecker wrote:
> 
> > While at it, this is a proposition for a reimplementation of isolcpus=
> > that doesn't involve  scheduler domain isolation. Therefore this
> > brings a behaviour change: all user tasks inherit init/1 affinity which
> > avoid the isolcpus= range. But if a task later overrides its affinity
> > which turns out to intersect an isolated CPU, load balancing may occur
> > on it.
> 
> 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.