rcu: Add tracing to irq/NMI dyntick-idle transitions

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

1 files changed, 6 insertions, 0 deletions

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 444aa2b3f24d..d069ba2d8412 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -880,12 +880,15 @@ void rcu_nmi_exit(void)
          * leave it in non-RCU-idle state.
          */
         if (rdtp->dynticks_nmi_nesting != 1) {
+                trace_rcu_dyntick(TPS("--="), rdtp->dynticks_nmi_nesting,
+                                  rdtp->dynticks_nmi_nesting - 2);
                 WRITE_ONCE(rdtp->dynticks_nmi_nesting, /* No store tearing. */
                            rdtp->dynticks_nmi_nesting - 2);
                 return;
         }
 
         /* This NMI interrupted an RCU-idle CPU, restore RCU-idleness. */
+        trace_rcu_dyntick(TPS("Startirq"), rdtp->dynticks_nmi_nesting, 0);
         WRITE_ONCE(rdtp->dynticks_nmi_nesting, 0); /* Avoid store tearing. */
         rcu_dynticks_eqs_enter();
 }
@@ -1057,6 +1060,9 @@ void rcu_nmi_enter(void)
                 rcu_dynticks_eqs_exit();
                 incby = 1;
         }
+        trace_rcu_dyntick(incby == 1 ? TPS("Endirq") : TPS("++="),
+                          rdtp->dynticks_nmi_nesting,
+                          rdtp->dynticks_nmi_nesting + incby);
         WRITE_ONCE(rdtp->dynticks_nmi_nesting, /* Prevent store tearing. */
                    rdtp->dynticks_nmi_nesting + incby);
         barrier();