| Message ID | 20240913214205.12359-4-frederic@kernel.org (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | rcu/nocb updates | expand |
diff --git a/kernel/rcu/tree_nocb.h b/kernel/rcu/tree_nocb.h index 0c9eca1cc76e..755ada098035 100644 --- a/kernel/rcu/tree_nocb.h +++ b/kernel/rcu/tree_nocb.h @@ -493,7 +493,7 @@ static bool rcu_nocb_try_bypass(struct rcu_data *rdp, struct rcu_head *rhp, trace_rcu_nocb_wake(rcu_state.name, rdp->cpu, TPS("FirstBQ")); } rcu_nocb_bypass_unlock(rdp); - smp_mb(); /* Order enqueue before wake. */ + // A wake up of the grace period kthread or timer adjustment // needs to be done only if: // 1. Bypass list was fully empty before (this is the first
Pre-GP accesses performed by the update side must be ordered against post-GP accesses performed by the readers. This is ensured by the bypass or nocb locking on enqueue time, followed by the fully ordered rnp locking initiated while callbacks are accelerated, and then propagated throughout the whole GP lifecyle associated with the callbacks. Therefore the explicit barrier advertizing ordering between bypass enqueue and rcuo wakeup is superfluous. If anything, it would even only order the first bypass callback enqueue against the rcuo wakeup and ignore all the subsequent ones. Remove the needless barrier. Signed-off-by: Frederic Weisbecker <frederic@kernel.org> --- kernel/rcu/tree_nocb.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)