Commit 457d1f46 authored by Chen Yu's avatar Chen Yu Committed by Peter Zijlstra

sched: Extract the task putting code from pick_next_task()

Introduce a new function put_prev_task_balance() to do the balance
when necessary, and then put previous task back to the run queue.
This function is extracted from pick_next_task() to prepare for
future usage by other type of task picking logic.

No functional change.
Suggested-by: default avatarPeter Zijlstra <peterz@infradead.org>
Signed-off-by: default avatarChen Yu <yu.c.chen@intel.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: default avatarValentin Schneider <valentin.schneider@arm.com>
Reviewed-by: default avatarVincent Guittot <vincent.guittot@linaro.org>
Reviewed-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
Link: https://lkml.kernel.org/r/5a99860cf66293db58a397d6248bcb2eee326776.1587464698.git.yu.c.chen@intel.com
parent d91cecc1
......@@ -3899,6 +3899,28 @@ static inline void schedule_debug(struct task_struct *prev, bool preempt)
schedstat_inc(this_rq()->sched_count);
}
static void put_prev_task_balance(struct rq *rq, struct task_struct *prev,
struct rq_flags *rf)
{
#ifdef CONFIG_SMP
const struct sched_class *class;
/*
* We must do the balancing pass before put_prev_task(), such
* that when we release the rq->lock the task is in the same
* state as before we took rq->lock.
*
* We can terminate the balance pass as soon as we know there is
* a runnable task of @class priority or higher.
*/
for_class_range(class, prev->sched_class, &idle_sched_class) {
if (class->balance(rq, prev, rf))
break;
}
#endif
put_prev_task(rq, prev);
}
/*
* Pick up the highest-prio task:
*/
......@@ -3932,22 +3954,7 @@ pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
}
restart:
#ifdef CONFIG_SMP
/*
* We must do the balancing pass before put_next_task(), such
* that when we release the rq->lock the task is in the same
* state as before we took rq->lock.
*
* We can terminate the balance pass as soon as we know there is
* a runnable task of @class priority or higher.
*/
for_class_range(class, prev->sched_class, &idle_sched_class) {
if (class->balance(rq, prev, rf))
break;
}
#endif
put_prev_task(rq, prev);
put_prev_task_balance(rq, prev, rf);
for_each_class(class) {
p = class->pick_next_task(rq);
......
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