events, sched: Add tracepoint for accounting blocked time

This tracepoint shows how long a task is sleeping in uninterruptible state.

E.g. it may show how long and where a mutex is waited for.

Signed-off-by: Andrew Vagin <avagin@openvz.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1322471015-107825-8-git-send-email-avagin@openvz.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 2 insertions, 0 deletions

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index cd3b64219d9f..7c62e2bf234f 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -1030,6 +1030,8 @@ static void enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se)
                                 trace_sched_stat_iowait(tsk, delta);
                         }
 
+                        trace_sched_stat_blocked(tsk, delta);
+
                         /*
                          * Blocking time is in units of nanosecs, so shift by
                          * 20 to get a milliseconds-range estimation of the