From b6e2c4ed35c33d7e55197aa26d99645a690ca467 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Tue, 23 Feb 2021 01:10:07 +0100 Subject: rcu/nocb: Cancel nocb_timer upon nocb_gp wakeup When waking up in nocb_gp_wait(), there is no need to keep the nocb_timer around because this function will traverse the whole rdp list. Any update performed before the timer was armed will now be visible after the ->nocb_gp_lock acquire. Signed-off-by: Frederic Weisbecker Cc: Josh Triplett Cc: Lai Jiangshan Cc: Joel Fernandes Cc: Neeraj Upadhyay Cc: Boqun Feng Signed-off-by: Paul E. McKenney --- kernel/rcu/tree_plugin.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'kernel/rcu') diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index 015adec5bdc5..a667551a5501 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -2211,6 +2211,10 @@ static void nocb_gp_wait(struct rcu_data *my_rdp) raw_spin_lock_irqsave(&my_rdp->nocb_gp_lock, flags); if (bypass) del_timer(&my_rdp->nocb_bypass_timer); + if (my_rdp->nocb_defer_wakeup > RCU_NOCB_WAKE_NOT) { + WRITE_ONCE(my_rdp->nocb_defer_wakeup, RCU_NOCB_WAKE_NOT); + del_timer(&my_rdp->nocb_timer); + } WRITE_ONCE(my_rdp->nocb_gp_sleep, true); raw_spin_unlock_irqrestore(&my_rdp->nocb_gp_lock, flags); } -- cgit v1.2.3