Re: [PATCH 7/7 v3] sched: fix wrong utilization accounting when switching to fair class

From: Peter Zijlstra
Date: Mon Sep 26 2016 - 10:54:09 EST

On Thu, Sep 22, 2016 at 02:25:18PM +0200, Peter Zijlstra wrote:
> On Tue, Sep 20, 2016 at 03:06:04PM +0200, Vincent Guittot wrote:
> > > Also, even it things magically worked out, its still very icky to mix
> > > the normalized vruntime into things.
> >
> > I agree
> In any case, I pushed out a bunch of patches to:
> git:// sched/tmp
> they appear to be able to build a kernel, but that's not much testing.

Hurmph, its buggered for cgroups. When we get the newidle lockbreak
between dequeue and put_prev_task, the load-balance pull can add a task
to the 'current' cgroup.

Which suggests we cannot do that enqueue_entity() optimization, unless
we fix that dequeue+put atomicy muck.