sched/fair: do not expose some tracepoints to user if CONFIG_SCHEDSTATS is not set [Linux 5.2]

sched/fair: do not expose some tracepoints to user if CONFIG_SCHEDSTATS is not set [Linux 5.2]

This Linux kernel change "sched/fair: do not expose some tracepoints to user if CONFIG_SCHEDSTATS is not set" is included in the Linux 5.2 release. This change is authored by Yafang Shao <laoar.shao [at] gmail.com> on Tue Mar 26 20:13:10 2019 +0800. The commit for this change in Linux stable tree is 2a09b5d (patch).

sched/fair: do not expose some tracepoints to user if CONFIG_SCHEDSTATS is not set

The tracepoints trace_sched_stat_{iowait, blocked, wait, sleep} should
be not exposed to user if CONFIG_SCHEDSTATS is not set.

Link: http://lkml.kernel.org/r/1553602391-11926-3-git-send-email-laoar.shao@gmail.com

Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

There are 21 lines of Linux source code added/deleted in this change. Code changes to Linux kernel are as follows.

 include/trace/events/sched.h | 21 ++++++++++++++-------
 1 file changed, 14 insertions(+), 7 deletions(-)

diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h
index 9a4bdfa..c8c7c7e 100644
--- a/include/trace/events/sched.h
+++ b/include/trace/events/sched.h
@@ -241,7 +241,6 @@ static inline long __trace_sched_switch_state(bool preempt, struct task_struct *
 DEFINE_EVENT(sched_process_template, sched_process_free,
         TP_PROTO(struct task_struct *p),
         TP_ARGS(p));
-        

 /*
  * Tracepoint for a task exiting:
@@ -336,11 +335,20 @@ static inline long __trace_sched_switch_state(bool preempt, struct task_struct *
          __entry->pid, __entry->old_pid)
 );

+
+#ifdef CONFIG_SCHEDSTATS
+#define DEFINE_EVENT_SCHEDSTAT DEFINE_EVENT
+#define DECLARE_EVENT_CLASS_SCHEDSTAT DECLARE_EVENT_CLASS
+#else
+#define DEFINE_EVENT_SCHEDSTAT DEFINE_EVENT_NOP
+#define DECLARE_EVENT_CLASS_SCHEDSTAT DECLARE_EVENT_CLASS_NOP
+#endif
+
 /*
  * XXX the below sched_stat tracepoints only apply to SCHED_OTHER/BATCH/IDLE
  *     adding sched_stat support to SCHED_FIFO/RR would be welcome.
  */
-DECLARE_EVENT_CLASS(sched_stat_template,
+DECLARE_EVENT_CLASS_SCHEDSTAT(sched_stat_template,

    TP_PROTO(struct task_struct *tsk, u64 delay),

@@ -363,12 +371,11 @@ static inline long __trace_sched_switch_state(bool preempt, struct task_struct *
            (unsigned long long)__entry->delay)
 );

-
 /*
  * Tracepoint for accounting wait time (time the task is runnable
  * but not actually running due to scheduler contention).
  */
-DEFINE_EVENT(sched_stat_template, sched_stat_wait,
+DEFINE_EVENT_SCHEDSTAT(sched_stat_template, sched_stat_wait,
         TP_PROTO(struct task_struct *tsk, u64 delay),
         TP_ARGS(tsk, delay));

@@ -376,7 +383,7 @@ static inline long __trace_sched_switch_state(bool preempt, struct task_struct *
  * Tracepoint for accounting sleep time (time the task is not runnable,
  * including iowait, see below).
  */
-DEFINE_EVENT(sched_stat_template, sched_stat_sleep,
+DEFINE_EVENT_SCHEDSTAT(sched_stat_template, sched_stat_sleep,
         TP_PROTO(struct task_struct *tsk, u64 delay),
         TP_ARGS(tsk, delay));

@@ -384,14 +391,14 @@ static inline long __trace_sched_switch_state(bool preempt, struct task_struct *
  * Tracepoint for accounting iowait time (time the task is not runnable
  * due to waiting on IO to complete).
  */
-DEFINE_EVENT(sched_stat_template, sched_stat_iowait,
+DEFINE_EVENT_SCHEDSTAT(sched_stat_template, sched_stat_iowait,
         TP_PROTO(struct task_struct *tsk, u64 delay),
         TP_ARGS(tsk, delay));

 /*
  * Tracepoint for accounting blocked time (time the task is in uninterruptible).
  */
-DEFINE_EVENT(sched_stat_template, sched_stat_blocked,
+DEFINE_EVENT_SCHEDSTAT(sched_stat_template, sched_stat_blocked,
         TP_PROTO(struct task_struct *tsk, u64 delay),
         TP_ARGS(tsk, delay));

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