Re: [PATCH] v2 Teach RCU that idle task is not quiscent state atboot

[Paul E. McKenney]

On Tue, Feb 24, 2009 at 03:02:56PM +1100, Nick Piggin wrote:
> On Tuesday 24 February 2009 07:43:32 Paul E. McKenney wrote:
> 
> > @@ -80,6 +81,10 @@ void wakeme_after_rcu(struct rcu_head  *head)
> >  void synchronize_rcu(void)
> >  {
> >  	struct rcu_synchronize rcu;
> > +
> > +	if (num_online_cpus() == 1)
> > +		return;  /* If UP, synchronize_rcu() is a grace period! */
> > +
> 
> Nice patch... May I just suggest a comment to say that this is
> also a correctness requirement due to the grace period holdoff
> for early boot?

Excellent point!  If Ingo reports that this actually fixes the hang that
he saw, I will add such a comment.

(And glad you like the patch!)

							Thanx, Paul
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