On Tue, Mar 16, 2021 at 12:45:26PM +0100, Frederic Weisbecker wrote:
> On Mon, Mar 15, 2021 at 08:02:39PM -0700, Paul E. McKenney wrote:
> > On Tue, Feb 23, 2021 at 01:10:10AM +0100, Frederic Weisbecker wrote:
> > > Provide a way to tune the deferred wakeup level we want to perform from
> > > a safe wakeup point. Currently those sites are:
> > >
> > > * nocb_timer
> > > * user/idle/guest entry
> > > * CPU down
> > > * softirq/rcuc
> > >
> > > All of these sites perform the wake up for both RCU_NOCB_WAKE and
> > > RCU_NOCB_WAKE_FORCE.
> > >
> > > In order to merge nocb_timer and nocb_bypass_timer together, we plan to
> > > add a new RCU_NOCB_WAKE_BYPASS that really want to be deferred until
> > > a timer fires so that we don't wake up the NOCB-gp kthread too early.
> > >
> > > To prepare for that, integrate a wake up level/limit that a callsite is
> > > deemed to perform.
> >
> > This appears to need the following in order to build for non-NOCB
> > configurations. I will fold it in and am retesting.
> >
> > Thanx, Paul
> >
> > ------------------------------------------------------------------------
> >
> > commit 55f59dd75a11455cf558fd387fbf9011017dcc8a
> > Author: Paul E. McKenney <paulmck@xxxxxxxxxx>
> > Date: Mon Mar 15 20:00:34 2021 -0700
> >
> > squash! rcu/nocb: Prepare for fine-grained deferred wakeup
> >
> > [ paulmck: Fix non-NOCB rcu_nocb_need_deferred_wakeup() definition. ]
> > Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
> >
> > diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
> > index 0cc7f68..dfb048e 100644
> > --- a/kernel/rcu/tree_plugin.h
> > +++ b/kernel/rcu/tree_plugin.h
> > @@ -2926,7 +2926,7 @@ static void __init rcu_boot_init_nocb_percpu_data(struct rcu_data *rdp)
> > {
> > }
> >
> > -static int rcu_nocb_need_deferred_wakeup(struct rcu_data *rdp)
> > +static int rcu_nocb_need_deferred_wakeup(struct rcu_data *rdp, int level)
> > {
> > return false;
> > }
>
> Oops thanks, I missed that.
And with this, light rcutorture testing passed. I hope to pound on it
harder later this week.
Thanx, Paul
