Re: [RFC patch 2/5] smpboot: Provide infrastructure for percpu hotplug threads

Peter Zijlstra
2012-06-14T08:17:37Z

On Thu, 2012-06-14 at 10:08 +0200, Peter Zijlstra wrote:
> On Wed, 2012-06-13 at 20:56 +0200, Thomas Gleixner wrote:
> > If it's just a spurious wakeup then it goes back to sleep right away
> > as nothing cleared the park bit.
>
> Your spurious wakeup will have destroyed the binding though. So you need
> to be careful.

We should probably do something like the below..

TJ does this wreck workqueues? Its somewhat 'creative' in that regard
and really wants fixing.

---
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5018,6 +5018,8 @@ void do_set_cpus_allowed(struct task_str

cpumask_copy(&p->cpus_allowed, new_mask);
p->nr_cpus_allowed = cpumask_weight(new_mask);
+ if (p->nr_cpus_allowed != 1)
+ p->flags &= ~PF_THREAD_BOUND;
}

/*