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
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commit 55f59dd75a11455cf558fd387fbf9011017dcc8a Author: Paul E. McKenney paulmck@kernel.org 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@kernel.org
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; }