rcu: add tracing for TINY_RCU and TINY_PREEMPT_RCU

Add tracing for the tiny RCU implementations, including statistics on
boosting in the case of TINY_PREEMPT_RCU and RCU_BOOST.

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

1 files changed, 4 insertions, 0 deletions

diff --git a/kernel/rcutiny.c b/kernel/rcutiny.c
index 93d166582cbb..034493724749 100644
--- a/kernel/rcutiny.c
+++ b/kernel/rcutiny.c
@@ -144,6 +144,7 @@ static void rcu_process_callbacks(struct rcu_ctrlblk *rcp)
 {
         struct rcu_head *next, *list;
         unsigned long flags;
+        RCU_TRACE(int cb_count = 0);
 
         /* If no RCU callbacks ready to invoke, just return. */
         if (&rcp->rcucblist == rcp->donetail)
@@ -169,7 +170,9 @@ static void rcu_process_callbacks(struct rcu_ctrlblk *rcp)
                 list->func(list);
                 local_bh_enable();
                 list = next;
+                RCU_TRACE(cb_count++);
         }
+        RCU_TRACE(rcu_trace_sub_qlen(rcp, cb_count));
 }
 
 /*
@@ -252,6 +255,7 @@ static void __call_rcu(struct rcu_head *head,
         local_irq_save(flags);
         *rcp->curtail = head;
         rcp->curtail = &head->next;
+        RCU_TRACE(rcp->qlen++);
         local_irq_restore(flags);
 }