ftrace: clean up enable logic for sched_switch
Unify sched_switch and sched_wakeup's action to following logic:
Do record_cmdline when start_cmdline_record() is called.
Start tracing events when the tracer is started.
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
LKML-Reference: <49D1C596.5050203@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c
index 9117cea..9d8cccd 100644
--- a/kernel/trace/trace_sched_switch.c
+++ b/kernel/trace/trace_sched_switch.c
@@ -29,13 +29,13 @@
int cpu;
int pc;
- if (!sched_ref || sched_stopped)
+ if (unlikely(!sched_ref))
return;
tracing_record_cmdline(prev);
tracing_record_cmdline(next);
- if (!tracer_enabled)
+ if (!tracer_enabled || sched_stopped)
return;
pc = preempt_count();
@@ -56,15 +56,15 @@
unsigned long flags;
int cpu, pc;
- if (!likely(tracer_enabled))
+ if (unlikely(!sched_ref))
+ return;
+
+ tracing_record_cmdline(current);
+
+ if (!tracer_enabled || sched_stopped)
return;
pc = preempt_count();
- tracing_record_cmdline(current);
-
- if (sched_stopped)
- return;
-
local_irq_save(flags);
cpu = raw_smp_processor_id();
data = ctx_trace->data[cpu];