rcu: Add expedited-grace-period event tracing

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

1 files changed, 13 insertions, 7 deletions

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 79e9206a7b11..524026fd9dd7 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -3584,17 +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)) {
+                trace_rcu_exp_grace_period(rsp->name, s, TPS("done"));
                 if (rnp) {
-                        mutex_unlock(&rnp->exp_funnel_mutex);
                         trace_rcu_exp_funnel_lock(rsp->name, rnp->level,
                                                   rnp->grplo, rnp->grphi,
                                                   TPS("rel"));
+                        mutex_unlock(&rnp->exp_funnel_mutex);
                 } 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"));
+                        mutex_unlock(&rdp->exp_funnel_mutex);
                 }
                 /* Ensure test happens before caller kfree(). */
                 smp_mb__before_atomic(); /* ^^^ */
@@ -3624,12 +3625,12 @@ static struct rcu_node *exp_funnel_lock(struct rcu_state *rsp, unsigned long s)
         rnp0 = rcu_get_root(rsp);
         if (!mutex_is_locked(&rnp0->exp_funnel_mutex)) {
                 if (mutex_trylock(&rnp0->exp_funnel_mutex)) {
-                        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"));
+                        if (sync_exp_work_done(rsp, rnp0, NULL,
+                                               &rdp->expedited_workdone0, s))
+                                return NULL;
                         return rnp0;
                 }
         }
@@ -3656,16 +3657,16 @@ static struct rcu_node *exp_funnel_lock(struct rcu_state *rsp, unsigned long s)
                 trace_rcu_exp_funnel_lock(rsp->name, rnp0->level,
                                           rnp0->grplo, rnp0->grphi, TPS("acq"));
                 if (rnp1) {
-                        mutex_unlock(&rnp1->exp_funnel_mutex);
                         trace_rcu_exp_funnel_lock(rsp->name, rnp1->level,
                                                   rnp1->grplo, rnp1->grphi,
                                                   TPS("rel"));
+                        mutex_unlock(&rnp1->exp_funnel_mutex);
                 } else {
-                        mutex_unlock(&rdp->exp_funnel_mutex);
                         trace_rcu_exp_funnel_lock(rsp->name,
                                                   rdp->mynode->level + 1,
                                                   rdp->cpu, rdp->cpu,
                                                   TPS("rel"));
+                        mutex_unlock(&rdp->exp_funnel_mutex);
                 }
                 rnp1 = rnp0;
         }
@@ -3895,16 +3896,21 @@ void synchronize_sched_expedited(void)
 
         /* Take a snapshot of the sequence number.  */
         s = rcu_exp_gp_seq_snap(rsp);
+        trace_rcu_exp_grace_period(rsp->name, s, TPS("snap"));
 
         rnp = exp_funnel_lock(rsp, s);
         if (rnp == NULL)
                 return;  /* Someone else did our work for us. */
 
         rcu_exp_gp_seq_start(rsp);
+        trace_rcu_exp_grace_period(rsp->name, s, TPS("start"));
         sync_rcu_exp_select_cpus(rsp, sync_sched_exp_handler);
         synchronize_sched_expedited_wait(rsp);
 
         rcu_exp_gp_seq_end(rsp);
+        trace_rcu_exp_grace_period(rsp->name, s, TPS("end"));
+        trace_rcu_exp_funnel_lock(rsp->name, rnp->level,
+                                  rnp->grplo, rnp->grphi, TPS("rel"));
         mutex_unlock(&rnp->exp_funnel_mutex);
 }
 EXPORT_SYMBOL_GPL(synchronize_sched_expedited);