Re: [patch] sched: fix b5d9d734 blunder in task_new_fair()

Peter Zijlstra
2009-11-24T18:27:23Z

On Tue, 2009-11-24 at 19:21 +0100, Mike Galbraith wrote:
> On Tue, 2009-11-24 at 18:54 +0100, Peter Zijlstra wrote:
> > On Tue, 2009-11-24 at 18:35 +0100, Peter Zijlstra wrote:
> > > On Tue, 2009-11-24 at 18:07 +0100, Mike Galbraith wrote:
> > > > > if (p->sched_class->task_new) {
> > > > > /* can detect migration through: task_cpu(p) != smp_processor_id() */
> > > >
> > > > What if the parent was migrated before we got here?
> > >
> > > Well, the only case it really matters for is the child_runs_first crap,
> > > which is basically broken on SMP anyway, so I don't think we care too
> > > much if we race here.
> > >
> > > Unless I missed some detail that is ;-)
> >
> >
> > Also, we're running all this from the parent context, and we have
> > preemption disabled, we're not going anywhere.
>
> In sched_fork() and wake_up_new_process(), but in between?

Hmm, right, back to the previous argument then ;-)