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>
diff --git a/kernel/sched_debug.c b/kernel/sched_debug.c
index 57ee9d5..823b63a 100644
--- a/kernel/sched_debug.c
+++ b/kernel/sched_debug.c
@@ -136,6 +136,8 @@
 			SPLIT_NS(spread0));
 	SEQ_printf(m, "  .%-30s: %ld\n", "nr_running", cfs_rq->nr_running);
 	SEQ_printf(m, "  .%-30s: %ld\n", "load", cfs_rq->load.weight);
+	SEQ_printf(m, "  .%-30s: %ld\n", "bkl_cnt",
+			rq->bkl_cnt);
 }
 
 static void print_cpu(struct seq_file *m, int cpu)
@@ -323,6 +325,7 @@
 	PN(se.exec_max);
 	PN(se.slice_max);
 	PN(se.wait_max);
+	P(sched_info.bkl_cnt);
 #endif
 	SEQ_printf(m, "%-25s:%20Ld\n",
 		   "nr_switches", (long long)(p->nvcsw + p->nivcsw));
@@ -350,6 +353,7 @@
 	p->se.exec_max			= 0;
 	p->se.slice_max			= 0;
 	p->se.wait_max			= 0;
+	p->sched_info.bkl_cnt		= 0;
 #endif
 	p->se.sum_exec_runtime		= 0;
 	p->se.prev_sum_exec_runtime	= 0;