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;
}
