sched debug: BKL usage statistics

add per task and per rq BKL usage statistics.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 9 insertions, 0 deletions

diff --git a/kernel/sched.c b/kernel/sched.c
index f33608e9e1a2..5004dff91850 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -356,6 +356,9 @@ struct rq {
         /* try_to_wake_up() stats */
         unsigned long ttwu_cnt;
         unsigned long ttwu_local;
+
+        /* BKL stats */
+        unsigned long bkl_cnt;
 #endif
         struct lock_class_key rq_lock_key;
 };
@@ -3414,6 +3417,12 @@ static inline void schedule_debug(struct task_struct *prev)
         profile_hit(SCHED_PROFILING, __builtin_return_address(0));
 
         schedstat_inc(this_rq(), sched_cnt);
+#ifdef CONFIG_SCHEDSTATS
+        if (unlikely(prev->lock_depth >= 0)) {
+                schedstat_inc(this_rq(), bkl_cnt);
+                schedstat_inc(prev, sched_info.bkl_cnt);
+        }
+#endif
 }
 
 /*