sched: fix tracepoints in scheduler

The trace point only caught one of many places where a task changes cpu,
put it in the right place to we get all of them.

Change the signature while we're at it.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

include/trace/sched.h

@@ -30,8 +30,8 @@ DECLARE_TRACE(sched_switch,
 		TPARGS(rq, prev, next));
 
 DECLARE_TRACE(sched_migrate_task,
-	TPPROTO(struct rq *rq, struct task_struct *p, int dest_cpu),
-		TPARGS(rq, p, dest_cpu));
+	TPPROTO(struct task_struct *p, int orig_cpu, int dest_cpu),
+		TPARGS(p, orig_cpu, dest_cpu));
 
 DECLARE_TRACE(sched_process_free,
 	TPPROTO(struct task_struct *p),

kernel/sched.c

@@ -1851,6 +1851,8 @@ 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);
+
 #ifdef CONFIG_SCHEDSTATS
 	if (p->se.wait_start)
 		p->se.wait_start -= clock_offset;
@@ -2868,7 +2870,6 @@ static void sched_migrate_task(struct task_struct *p, int dest_cpu)
 	    || unlikely(!cpu_active(dest_cpu)))
 		goto out;
 
-	trace_sched_migrate_task(rq, p, dest_cpu);
 	/* force the process onto the specified CPU */
 	if (migrate_task(p, dest_cpu, &req)) {
 		/* Need to wait for migration thread (might exit: take ref). */