Commit-ID:  4ff648decf4712d39f184fc2df3163f43975575a
Gitweb:     https://git.kernel.org/tip/4ff648decf4712d39f184fc2df3163f43975575a
Author:     Sebastian Andrzej Siewior <[email protected]>
AuthorDate: Thu, 24 May 2018 15:26:48 +0200
Committer:  Ingo Molnar <[email protected]>
CommitDate: Fri, 25 May 2018 08:04:01 +0200

sched, tracing: Fix trace_sched_pi_setprio() for deboosting

Since the following 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"34 oldprio˜ newprio=3D98
  |futex sched_switch: prev_comm=futex_requeue_p prev_pid"34 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"20 oldprio˜ newprio=3D120
  |futex sched_switch: prev_comm=futex_requeue_p prev_pid"20 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 <[email protected]>
Signed-off-by: Sebastian Andrzej Siewior <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Fixes: b91473ff6e97 ("sched,tracing: Update trace_sched_pi_setprio()")
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
---
 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 */
        ),
 

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