rcu: Add funnel-locking tracing for expedited grace periods

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 178575c..79e9206 100644 (file)
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -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)
 {
        if (rcu_exp_gp_seq_done(rsp, s)) {
-               if (rnp)
+               if (rnp) {
                        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);
+                       trace_rcu_exp_funnel_lock(rsp->name,
+                                                 rdp->mynode->level + 1,
+                                                 rdp->cpu, rdp->cpu,
+                                                 TPS("rel"));
+               }
                /* Ensure test happens before caller kfree(). */
                smp_mb__before_atomic(); /* ^^^ */
                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,
                                               &rdp->expedited_workdone0, s))
                                return NULL;
+                       trace_rcu_exp_funnel_lock(rsp->name, rnp0->level,
+                                                 rnp0->grplo, rnp0->grphi,
+                                                 TPS("acq"));
                        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))
                return NULL;
        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;
        for (; rnp0 != NULL; rnp0 = rnp0->parent) {
                if (sync_exp_work_done(rsp, rnp1, rdp,
                                       &rdp->expedited_workdone2, s))
                        return NULL;
                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);
-               else
+                       trace_rcu_exp_funnel_lock(rsp->name, rnp1->level,
+                                                 rnp1->grplo, rnp1->grphi,
+                                                 TPS("rel"));
+               } else {
                        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;
        }
        if (sync_exp_work_done(rsp, rnp1, rdp,

diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index a2ac262..cd2dae4 100644 (file)
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -767,6 +767,9 @@ void synchronize_rcu_expedited(void)
        /* Clean up and exit. */
        rcu_exp_gp_seq_end(rsp);
        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);