Re: [patch] RCU: introduce rcu_soon_pending() interface

[Paul E. McKenney]

On Mon, Apr 24, 2006 at 04:09:43PM -0700, Andrew Morton wrote:
> Heiko Carstens <heiko.carstens@xxxxxxxxxx> wrote:
> >
> > @@ -485,6 +485,14 @@ int rcu_pending(int cpu)
> >  		__rcu_pending(&rcu_bh_ctrlblk, &per_cpu(rcu_bh_data, cpu));
> >  }
> >  
> > +int rcu_soon_pending(int cpu)
> > +{
> > +	struct rcu_data *rdp = &per_cpu(rcu_data, cpu);
> > +	struct rcu_data *rdp_bh = &per_cpu(rcu_bh_data, cpu);
> > +
> > +	return (!!rdp->curlist || !!rdp_bh->curlist);
> > +}
> 
> This patch sets my nerves a-jangling.
> 
> What are the units of soonness?  It's awfully waffly.  Can we specify this
> more tightly?
> 
> Neither rcu_pending() nor rcu_soon_pending() are commented or documented. 
> Pity the poor user trying to work out what they do, and how they differ. 
> They're global symbols and they form part of the RCU API - they should be
> kernel docified, please.

Please note that the rcu_pending() interface was never intended for
external use -- it is purely internal to the RCU infrastructure.
If there is a new external use for rcu_pending(), then it would need to
be documented.  But I would rather this one stay internal -- different
RCU implementations might need different things.

So, what are we trying to do here?

> There's probably a reason why neither of these symbols are exported to
> modules.  Once they're actually documented I mught be able to work out what
> that reason is ;)

The reason for rcu_pending() was that it is a private interface.

					Thanx, Paul
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