rcu: Add funnel-locking tracing for expedited grace periods

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

1 files changed, 27 insertions, 4 deletions

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 178575c01d09..79e9206a7b11 100644
--- 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,