[tip:sched/core] events, sched: Add tracepoint for accounting blocked time

[tip-bot for Andrew Vagin <avagin@openvz.org>]

Commit-ID:  b781a602ac745ee3d5d745276f1e1905a2c101f9
Gitweb:     http://git.kernel.org/tip/b781a602ac745ee3d5d745276f1e1905a2c101f9
Author:     Andrew Vagin <avagin@openvz.org>
AuthorDate: Mon, 28 Nov 2011 12:03:35 +0300
Committer:  Ingo Molnar <mingo@elte.hu>
CommitDate: Tue, 6 Dec 2011 08:51:23 +0100

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>
---
 include/trace/events/sched.h |    7 +++++++
 kernel/sched/fair.c          |    2 ++
 2 files changed, 9 insertions(+), 0 deletions(-)

diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h
index 959ff18..e33ed1b 100644
--- a/include/trace/events/sched.h
+++ b/include/trace/events/sched.h
@@ -331,6 +331,13 @@ DEFINE_EVENT(sched_stat_template, sched_stat_iowait,
 	     TP_ARGS(tsk, delay));
 
 /*
+ * Tracepoint for accounting blocked time (time the task is in uninterruptible).
+ */
+DEFINE_EVENT(sched_stat_template, sched_stat_blocked,
+	     TP_PROTO(struct task_struct *tsk, u64 delay),
+	     TP_ARGS(tsk, delay));
+
+/*
  * Tracepoint for accounting runtime (time the task is executing
  * on a CPU).
  */
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index cd3b642..7c62e2b 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