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Commit bea2de44 authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

rcu: Add funnel-locking tracing for expedited grace periods 



Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
parent e087816d

kernel/rcu/tree.c

+27 −4
Original line number Original line Diff line number Diff line
@@ -3584,10 +3584,18 @@ static bool sync_exp_work_done(struct rcu_state *rsp, struct rcu_node *rnp, 
			       atomic_long_t *stat, unsigned long s)

			       atomic_long_t *stat, unsigned long s)

{

{

	if (rcu_exp_gp_seq_done(rsp, s)) {

	if (rcu_exp_gp_seq_done(rsp, s)) {

		if (rnp)

		if (rnp) {

			mutex_unlock(&rnp->exp_funnel_mutex);

			mutex_unlock(&rnp->exp_funnel_mutex);

		else if (rdp)

			trace_rcu_exp_funnel_lock(rsp->name, rnp->level,

						  rnp->grplo, rnp->grphi,

						  TPS("rel"));

		} else if (rdp) {

			mutex_unlock(&rdp->exp_funnel_mutex);

			mutex_unlock(&rdp->exp_funnel_mutex);

			trace_rcu_exp_funnel_lock(rsp->name,

						  rdp->mynode->level + 1,

						  rdp->cpu, rdp->cpu,

						  TPS("rel"));

		}

		/* Ensure test happens before caller kfree(). */

		/* Ensure test happens before caller kfree(). */

		smp_mb__before_atomic(); /* ^^^ */

		smp_mb__before_atomic(); /* ^^^ */

		atomic_long_inc(stat);

		atomic_long_inc(stat);
@@ -3619,6 +3627,9 @@ static struct rcu_node *exp_funnel_lock(struct rcu_state *rsp, unsigned long s) 
			if (sync_exp_work_done(rsp, rnp0, NULL,

			if (sync_exp_work_done(rsp, rnp0, NULL,

					       &rdp->expedited_workdone0, s))

					       &rdp->expedited_workdone0, s))

				return NULL;

				return NULL;

			trace_rcu_exp_funnel_lock(rsp->name, rnp0->level,

						  rnp0->grplo, rnp0->grphi,

						  TPS("acq"));

			return rnp0;

			return rnp0;

		}

		}

	}

	}
@@ -3634,16 +3645,28 @@ static struct rcu_node *exp_funnel_lock(struct rcu_state *rsp, unsigned long s) 
	if (sync_exp_work_done(rsp, NULL, NULL, &rdp->expedited_workdone1, s))

	if (sync_exp_work_done(rsp, NULL, NULL, &rdp->expedited_workdone1, s))

		return NULL;

		return NULL;

	mutex_lock(&rdp->exp_funnel_mutex);

	mutex_lock(&rdp->exp_funnel_mutex);

	trace_rcu_exp_funnel_lock(rsp->name, rdp->mynode->level + 1,

				  rdp->cpu, rdp->cpu, TPS("acq"));

	rnp0 = rdp->mynode;

	rnp0 = rdp->mynode;

	for (; rnp0 != NULL; rnp0 = rnp0->parent) {

	for (; rnp0 != NULL; rnp0 = rnp0->parent) {

		if (sync_exp_work_done(rsp, rnp1, rdp,

		if (sync_exp_work_done(rsp, rnp1, rdp,

				       &rdp->expedited_workdone2, s))

				       &rdp->expedited_workdone2, s))

			return NULL;

			return NULL;

		mutex_lock(&rnp0->exp_funnel_mutex);

		mutex_lock(&rnp0->exp_funnel_mutex);

		if (rnp1)

		trace_rcu_exp_funnel_lock(rsp->name, rnp0->level,

					  rnp0->grplo, rnp0->grphi, TPS("acq"));

		if (rnp1) {

			mutex_unlock(&rnp1->exp_funnel_mutex);

			mutex_unlock(&rnp1->exp_funnel_mutex);

		else

			trace_rcu_exp_funnel_lock(rsp->name, rnp1->level,

						  rnp1->grplo, rnp1->grphi,

						  TPS("rel"));

		} else {

			mutex_unlock(&rdp->exp_funnel_mutex);

			mutex_unlock(&rdp->exp_funnel_mutex);

			trace_rcu_exp_funnel_lock(rsp->name,

						  rdp->mynode->level + 1,

						  rdp->cpu, rdp->cpu,

						  TPS("rel"));

		}

		rnp1 = rnp0;

		rnp1 = rnp0;

	}

	}

	if (sync_exp_work_done(rsp, rnp1, rdp,

	if (sync_exp_work_done(rsp, rnp1, rdp,

kernel/rcu/tree_plugin.h

+3 −0
Original line number Original line Diff line number Diff line
@@ -767,6 +767,9 @@ void synchronize_rcu_expedited(void) 
	/* Clean up and exit. */

	/* Clean up and exit. */

	rcu_exp_gp_seq_end(rsp);

	rcu_exp_gp_seq_end(rsp);

	mutex_unlock(&rnp_unlock->exp_funnel_mutex);

	mutex_unlock(&rnp_unlock->exp_funnel_mutex);

	trace_rcu_exp_funnel_lock(rsp->name, rnp_unlock->level,

				  rnp_unlock->grplo, rnp_unlock->grphi,

				  TPS("rel"));

}

}

EXPORT_SYMBOL_GPL(synchronize_rcu_expedited);

EXPORT_SYMBOL_GPL(synchronize_rcu_expedited);