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Subject[PATCH v2] sched,tracing: Correct trace_sched_pi_setprio() for deboosting
Since commit b91473ff6e97 ("sched,tracing: Update
trace_sched_pi_setprio()") the sched_pi_setprio trace point shows the
"newprio" during a deboost:
|futex sched_pi_setprio: comm=futex_requeue_p pid=2234 oldprio=98 newprio=98
|futex sched_switch: prev_comm=futex_requeue_p prev_pid=2234 prev_prio=120

This patch open codes __rt_effective_prio() in the tracepoint as the
`newprio' to get the old behaviour back / the correct priority:

|futex sched_pi_setprio: comm=futex_requeue_p pid=2220 oldprio=98 newprio=120
|futex sched_switch: prev_comm=futex_requeue_p prev_pid=2220 prev_prio=120

Peter suggested to open code the new priority so people using tracehook
could get the deadline data out.

Reported-by: Mansky Christian <man@keba.com>
Fixes: b91473ff6e97 ("sched,tracing: Update trace_sched_pi_setprio()")
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
v1…v2: Open code __rt_effective_prio() in sched_pi_setprio macro as
suggested by PeterZ.

include/trace/events/sched.h | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h
index bc01e06bc716..0be866c91f62 100644
--- a/include/trace/events/sched.h
+++ b/include/trace/events/sched.h
@@ -435,7 +435,9 @@ TRACE_EVENT(sched_pi_setprio,
memcpy(__entry->comm, tsk->comm, TASK_COMM_LEN);
__entry->pid = tsk->pid;
__entry->oldprio = tsk->prio;
- __entry->newprio = pi_task ? pi_task->prio : tsk->prio;
+ __entry->newprio = pi_task ?
+ min(tsk->normal_prio, pi_task->prio) :
+ tsk->normal_prio;
/* XXX SCHED_DEADLINE bits missing */
),

--
2.17.0
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