sched: Rename task_running() to task_on_cpu()

There is some ambiguity about task_running() in that it is unrelated
to TASK_RUNNING but instead tests ->on_cpu. As such, rename the thing
task_on_cpu().

Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/Yxhkhn55uHZx+NGl@hirez.programming.kicks-ass.net

Author: Peter Zijlstra

kernel/sched/core.c

@@ -2777,7 +2777,7 @@ static int affine_move_task(struct rq *rq, struct task_struct *p, struct rq_flag
 		return -EINVAL;
 	}
 
-	if (task_running(rq, p) || READ_ONCE(p->__state) == TASK_WAKING) {
+	if (task_on_cpu(rq, p) || READ_ONCE(p->__state) == TASK_WAKING) {
 		/*
 		 * MIGRATE_ENABLE gets here because 'p == current', but for
 		 * anything else we cannot do is_migration_disabled(), punt
@@ -3289,11 +3289,11 @@ unsigned long wait_task_inactive(struct task_struct *p, unsigned int match_state
 		 *
 		 * NOTE! Since we don't hold any locks, it's not
 		 * even sure that "rq" stays as the right runqueue!
-		 * But we don't care, since "task_running()" will
+		 * But we don't care, since "task_on_cpu()" will
 		 * return false if the runqueue has changed and p
 		 * is actually now running somewhere else!
 		 */
-		while (task_running(rq, p)) {
+		while (task_on_cpu(rq, p)) {
 			if (match_state && unlikely(READ_ONCE(p->__state) != match_state))
 				return 0;
 			cpu_relax();
@@ -3306,7 +3306,7 @@ unsigned long wait_task_inactive(struct task_struct *p, unsigned int match_state
 		 */
 		rq = task_rq_lock(p, &rf);
 		trace_sched_wait_task(p);
-		running = task_running(rq, p);
+		running = task_on_cpu(rq, p);
 		queued = task_on_rq_queued(p);
 		ncsw = 0;
 		if (!match_state || READ_ONCE(p->__state) == match_state)
@@ -8648,7 +8648,7 @@ int __sched yield_to(struct task_struct *p, bool preempt)
 	if (curr->sched_class != p->sched_class)
 		goto out_unlock;
 
-	if (task_running(p_rq, p) || !task_is_running(p))
+	if (task_on_cpu(p_rq, p) || !task_is_running(p))
 		goto out_unlock;
 
 	yielded = curr->sched_class->yield_to_task(rq, p);

kernel/sched/core_sched.c

@@ -88,7 +88,7 @@ static unsigned long sched_core_update_cookie(struct task_struct *p,
 	 * core has now entered/left forced idle state. Defer accounting to the
 	 * next scheduling edge, rather than always forcing a reschedule here.
 	 */
-	if (task_running(rq, p))
+	if (task_on_cpu(rq, p))
 		resched_curr(rq);
 
 	task_rq_unlock(rq, p, &rf);

kernel/sched/deadline.c

@@ -2092,7 +2092,7 @@ static void task_fork_dl(struct task_struct *p)
 
 static int pick_dl_task(struct rq *rq, struct task_struct *p, int cpu)
 {
-	if (!task_running(rq, p) &&
+	if (!task_on_cpu(rq, p) &&
 	    cpumask_test_cpu(cpu, &p->cpus_mask))
 		return 1;
 	return 0;
@@ -2244,7 +2244,7 @@ static struct rq *find_lock_later_rq(struct task_struct *task, struct rq *rq)
 		if (double_lock_balance(rq, later_rq)) {
 			if (unlikely(task_rq(task) != rq ||
 				     !cpumask_test_cpu(later_rq->cpu, &task->cpus_mask) ||
-				     task_running(rq, task) ||
+				     task_on_cpu(rq, task) ||
 				     !dl_task(task) ||
 				     !task_on_rq_queued(task))) {
 				double_unlock_balance(rq, later_rq);
@@ -2474,7 +2474,7 @@ static void pull_dl_task(struct rq *this_rq)
  */
 static void task_woken_dl(struct rq *rq, struct task_struct *p)
 {
-	if (!task_running(rq, p) &&
+	if (!task_on_cpu(rq, p) &&
 	    !test_tsk_need_resched(rq->curr) &&
 	    p->nr_cpus_allowed > 1 &&
 	    dl_task(rq->curr) &&

kernel/sched/fair.c

@@ -7935,7 +7935,7 @@ int can_migrate_task(struct task_struct *p, struct lb_env *env)
 	/* Record that we found at least one task that could run on dst_cpu */
 	env->flags &= ~LBF_ALL_PINNED;
 
-	if (task_running(env->src_rq, p)) {
+	if (task_on_cpu(env->src_rq, p)) {
 		schedstat_inc(p->stats.nr_failed_migrations_running);
 		return 0;
 	}

kernel/sched/rt.c

@@ -1845,7 +1845,7 @@ static void put_prev_task_rt(struct rq *rq, struct task_struct *p)
 
 static int pick_rt_task(struct rq *rq, struct task_struct *p, int cpu)
 {
-	if (!task_running(rq, p) &&
+	if (!task_on_cpu(rq, p) &&
 	    cpumask_test_cpu(cpu, &p->cpus_mask))
 		return 1;
 
@@ -2000,7 +2000,7 @@ static struct rq *find_lock_lowest_rq(struct task_struct *task, struct rq *rq)
 			 */
 			if (unlikely(task_rq(task) != rq ||
 				     !cpumask_test_cpu(lowest_rq->cpu, &task->cpus_mask) ||
-				     task_running(rq, task) ||
+				     task_on_cpu(rq, task) ||
 				     !rt_task(task) ||
 				     !task_on_rq_queued(task))) {
 
@@ -2458,7 +2458,7 @@ static void pull_rt_task(struct rq *this_rq)
  */
 static void task_woken_rt(struct rq *rq, struct task_struct *p)
 {
-	bool need_to_push = !task_running(rq, p) &&
+	bool need_to_push = !task_on_cpu(rq, p) &&
 			    !test_tsk_need_resched(rq->curr) &&
 			    p->nr_cpus_allowed > 1 &&
 			    (dl_task(rq->curr) || rt_task(rq->curr)) &&

kernel/sched/sched.h

@@ -2051,7 +2051,7 @@ static inline int task_current(struct rq *rq, struct task_struct *p)
 	return rq->curr == p;
 }
 
-static inline int task_running(struct rq *rq, struct task_struct *p)
+static inline int task_on_cpu(struct rq *rq, struct task_struct *p)
 {
 #ifdef CONFIG_SMP
 	return p->on_cpu;