tracepoint: trace_sched_migrate_task(): remove parameter

The orig_cpu parameter in trace_sched_migrate_task() is not necessary,
it can be got by using task_cpu(p) in the probe.

[ Impact: micro-optimization ]

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
[ modified from Mathieu's patch. The original patch is at:
  http://marc.info/?l=linux-kernel&m=123791201716239&w=2 ]
Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Cc: fweisbec@gmail.com
Cc: rostedt@goodmis.org
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: zhaolei@cn.fujitsu.com
Cc: laijs@cn.fujitsu.com
LKML-Reference: <49FFFDB7.1050402@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

include/trace/events/sched.h

@@ -180,9 +180,9 @@ TRACE_EVENT(sched_switch,
  */
 TRACE_EVENT(sched_migrate_task,
 
-	TP_PROTO(struct task_struct *p, int orig_cpu, int dest_cpu),
+	TP_PROTO(struct task_struct *p, int dest_cpu),
 
-	TP_ARGS(p, orig_cpu, dest_cpu),
+	TP_ARGS(p, dest_cpu),
 
 	TP_STRUCT__entry(
 		__array(	char,	comm,	TASK_COMM_LEN	)
@@ -196,7 +196,7 @@ TRACE_EVENT(sched_migrate_task,
 		memcpy(__entry->comm, p->comm, TASK_COMM_LEN);
 		__entry->pid		= p->pid;
 		__entry->prio		= p->prio;
-		__entry->orig_cpu	= orig_cpu;
+		__entry->orig_cpu	= task_cpu(p);
 		__entry->dest_cpu	= dest_cpu;
 	),
 

kernel/sched.c

@@ -1954,7 +1954,7 @@ void set_task_cpu(struct task_struct *p, unsigned int new_cpu)
 
 	clock_offset = old_rq->clock - new_rq->clock;
 
-	trace_sched_migrate_task(p, task_cpu(p), new_cpu);
+	trace_sched_migrate_task(p, new_cpu);
 
 #ifdef CONFIG_SCHEDSTATS
 	if (p->se.wait_start)