Re: [PATCH RFC tip/core/rcu 1/2] rcu: suppress RCU lockdep warnings during early boot

["Paul E. McKenney" <paulmck@linux.vnet.ibm.com>]

On Tue, Mar 02, 2010 at 03:12:57PM +0100, Ingo Molnar wrote:
> 
> * Paul E. McKenney <paulmck@linux.vnet.ibm.com> wrote:
> 
> > On Tue, Mar 02, 2010 at 01:20:59PM +0100, Ingo Molnar wrote:
> > > 
> > > * Paul E. McKenney <paulmck@linux.vnet.ibm.com> wrote:
> > > 
> > > > +	if (!rcu_scheduler_active || !debug_locks)
> > > > +		return 1;
> > > > +	return lock_is_held(&rcu_lock_map);
> > > 
> > > > +	if (!rcu_scheduler_active || !debug_locks)
> > > > +		return 1;
> > > > +	return lock_is_held(&rcu_bh_lock_map);
> > > 
> > > i guess there could be a common helper here?
> > 
> > Will do!
> > 
> > > Also, could we clear rcu_scheduler_active when we clear debug_locks? That way 
> > > only a single test is needed, a generic 'is lock debugging active'.
> > 
> > Doing that will break synchronize_rcu(), which returns immediately if
> > !rcu_scheduler_active.
> 
> Ok - then have an debug_rcu flag which is cleared appropriately - so that the 
> fastpath impact is reduced?

Good point, will do!

							Thanx, Paul