[PATCH -v3 6/8] sched,tracing: Update trace_sched_pi_setprio()

From: Peter Zijlstra
Date: Thu Mar 23 2017 - 11:07:35 EST


Pass the PI donor task, instead of a numerical priority.

Numerical priorities are not sufficient to describe state ever since
SCHED_DEADLINE.

Annotate all sched tracepoints that are currently broken; fixing them
will bork userspace. *hate*.

Reviewed-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
---
include/trace/events/sched.h | 16 +++++++++-------
kernel/sched/core.c | 2 +-
2 files changed, 10 insertions(+), 8 deletions(-)

--- a/include/trace/events/sched.h
+++ b/include/trace/events/sched.h
@@ -70,7 +70,7 @@ DECLARE_EVENT_CLASS(sched_wakeup_templat
TP_fast_assign(
memcpy(__entry->comm, p->comm, TASK_COMM_LEN);
__entry->pid = p->pid;
- __entry->prio = p->prio;
+ __entry->prio = p->prio; /* XXX SCHED_DEADLINE */
__entry->success = 1; /* rudiment, kill when possible */
__entry->target_cpu = task_cpu(p);
),
@@ -147,6 +147,7 @@ TRACE_EVENT(sched_switch,
memcpy(__entry->prev_comm, prev->comm, TASK_COMM_LEN);
__entry->next_pid = next->pid;
__entry->next_prio = next->prio;
+ /* XXX SCHED_DEADLINE */
),

TP_printk("prev_comm=%s prev_pid=%d prev_prio=%d prev_state=%s%s ==> next_comm=%s next_pid=%d next_prio=%d",
@@ -181,7 +182,7 @@ TRACE_EVENT(sched_migrate_task,
TP_fast_assign(
memcpy(__entry->comm, p->comm, TASK_COMM_LEN);
__entry->pid = p->pid;
- __entry->prio = p->prio;
+ __entry->prio = p->prio; /* XXX SCHED_DEADLINE */
__entry->orig_cpu = task_cpu(p);
__entry->dest_cpu = dest_cpu;
),
@@ -206,7 +207,7 @@ DECLARE_EVENT_CLASS(sched_process_templa
TP_fast_assign(
memcpy(__entry->comm, p->comm, TASK_COMM_LEN);
__entry->pid = p->pid;
- __entry->prio = p->prio;
+ __entry->prio = p->prio; /* XXX SCHED_DEADLINE */
),

TP_printk("comm=%s pid=%d prio=%d",
@@ -253,7 +254,7 @@ TRACE_EVENT(sched_process_wait,
TP_fast_assign(
memcpy(__entry->comm, current->comm, TASK_COMM_LEN);
__entry->pid = pid_nr(pid);
- __entry->prio = current->prio;
+ __entry->prio = current->prio; /* XXX SCHED_DEADLINE */
),

TP_printk("comm=%s pid=%d prio=%d",
@@ -413,9 +414,9 @@ DEFINE_EVENT(sched_stat_runtime, sched_s
*/
TRACE_EVENT(sched_pi_setprio,

- TP_PROTO(struct task_struct *tsk, int newprio),
+ TP_PROTO(struct task_struct *tsk, struct task_struct *pi_task),

- TP_ARGS(tsk, newprio),
+ TP_ARGS(tsk, pi_task),

TP_STRUCT__entry(
__array( char, comm, TASK_COMM_LEN )
@@ -428,7 +429,8 @@ TRACE_EVENT(sched_pi_setprio,
memcpy(__entry->comm, tsk->comm, TASK_COMM_LEN);
__entry->pid = tsk->pid;
__entry->oldprio = tsk->prio;
- __entry->newprio = newprio;
+ __entry->newprio = pi_task ? pi_task->prio : tsk->prio;
+ /* XXX SCHED_DEADLINE bits missing */
),

TP_printk("comm=%s pid=%d oldprio=%d newprio=%d",
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3634,7 +3634,7 @@ void rt_mutex_setprio(struct task_struct
goto out_unlock;
}

- trace_sched_pi_setprio(p, prio); /* broken */
+ trace_sched_pi_setprio(p, pi_task);
oldprio = p->prio;

if (oldprio == prio)