rcu/nocb: EXP Check use and usefulness of ->nocb_lock_contended (6aacd88d) · Commits · 戴 / test

kernel/rcu/tree_plugin.h

+3 −1

Original line number	Diff line number	Diff line
		@@ -1515,6 +1515,7 @@ static void rcu_nocb_bypass_lock(struct rcu_data *rdp)
		if (raw_spin_trylock(&rdp->nocb_bypass_lock))
		return;
		atomic_inc(&rdp->nocb_lock_contended);
		WARN_ON_ONCE(smp_processor_id() != rdp->cpu);
		smp_mb__after_atomic(); /* atomic_inc() before lock. */
		raw_spin_lock(&rdp->nocb_bypass_lock);
		smp_mb__before_atomic(); /* atomic_dec() after lock. */
		@@ -1533,7 +1534,8 @@ static void rcu_nocb_bypass_lock(struct rcu_data *rdp)
		*/
		static void rcu_nocb_wait_contended(struct rcu_data *rdp)
		{
		while (atomic_read(&rdp->nocb_lock_contended))
		WARN_ON_ONCE(smp_processor_id() != rdp->cpu);
		while (WARN_ON_ONCE(atomic_read(&rdp->nocb_lock_contended)))
		cpu_relax();
		}