sched/core: Introduce set_next_task() helper for better code readability

When we pick the next task, we will do the following for the task:

  1) p->se.exec_start = rq_clock_task(rq);
  2) dequeue_pushable(_dl)_task(rq, p);

When we call set_curr_task(), we also need to do the same thing
above. In rt.c, the code at 1) is in the _pick_next_task_rt()
and the code at 2) is in the pick_next_task_rt(). If we put two
operations in one function, maybe better. So, we introduce a new
function set_next_task(), which is responsible for doing the above.

By introducing the function we can get rid of calling the
dequeue_pushable(_dl)_task() directly(We can call set_next_task())
in pick_next_task() and have better code readability and reuse.
In set_curr_task_rt(), we also can call set_next_task().

Do this things such that we end up with:

  static struct task_struct *pick_next_task(struct rq *rq,
  					    struct task_struct *prev,
  					    struct rq_flags *rf)
  {
  	/* do something else ... */

  	put_prev_task(rq, prev);

  	/* pick next task p */

  	set_next_task(rq, p);

  	/* do something else ... */
  }

put_prev_task() can match set_next_task(), which can make the
code more readable.

Signed-off-by: Muchun Song <smuchun@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20181026131743.21786-1-smuchun@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Muchun Song 2018-10-26 21:17:43 +08:00 committed by Ingo Molnar
parent 3f130a37c4
commit ff1cdc94de
2 changed files with 21 additions and 22 deletions

View File

@ -1695,6 +1695,14 @@ static void start_hrtick_dl(struct rq *rq, struct task_struct *p)
}
#endif
static inline void set_next_task(struct rq *rq, struct task_struct *p)
{
p->se.exec_start = rq_clock_task(rq);
/* You can't push away the running task */
dequeue_pushable_dl_task(rq, p);
}
static struct sched_dl_entity *pick_next_dl_entity(struct rq *rq,
struct dl_rq *dl_rq)
{
@ -1750,10 +1758,8 @@ pick_next_task_dl(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
BUG_ON(!dl_se);
p = dl_task_of(dl_se);
p->se.exec_start = rq_clock_task(rq);
/* Running task will never be pushed. */
dequeue_pushable_dl_task(rq, p);
set_next_task(rq, p);
if (hrtick_enabled(rq))
start_hrtick_dl(rq, p);
@ -1808,12 +1814,7 @@ static void task_fork_dl(struct task_struct *p)
static void set_curr_task_dl(struct rq *rq)
{
struct task_struct *p = rq->curr;
p->se.exec_start = rq_clock_task(rq);
/* You can't push away the running task */
dequeue_pushable_dl_task(rq, p);
set_next_task(rq, rq->curr);
}
#ifdef CONFIG_SMP

View File

@ -1498,6 +1498,14 @@ static void check_preempt_curr_rt(struct rq *rq, struct task_struct *p, int flag
#endif
}
static inline void set_next_task(struct rq *rq, struct task_struct *p)
{
p->se.exec_start = rq_clock_task(rq);
/* The running task is never eligible for pushing */
dequeue_pushable_task(rq, p);
}
static struct sched_rt_entity *pick_next_rt_entity(struct rq *rq,
struct rt_rq *rt_rq)
{
@ -1518,7 +1526,6 @@ static struct sched_rt_entity *pick_next_rt_entity(struct rq *rq,
static struct task_struct *_pick_next_task_rt(struct rq *rq)
{
struct sched_rt_entity *rt_se;
struct task_struct *p;
struct rt_rq *rt_rq = &rq->rt;
do {
@ -1527,10 +1534,7 @@ static struct task_struct *_pick_next_task_rt(struct rq *rq)
rt_rq = group_rt_rq(rt_se);
} while (rt_rq);
p = rt_task_of(rt_se);
p->se.exec_start = rq_clock_task(rq);
return p;
return rt_task_of(rt_se);
}
static struct task_struct *
@ -1573,8 +1577,7 @@ pick_next_task_rt(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
p = _pick_next_task_rt(rq);
/* The running task is never eligible for pushing */
dequeue_pushable_task(rq, p);
set_next_task(rq, p);
rt_queue_push_tasks(rq);
@ -2355,12 +2358,7 @@ static void task_tick_rt(struct rq *rq, struct task_struct *p, int queued)
static void set_curr_task_rt(struct rq *rq)
{
struct task_struct *p = rq->curr;
p->se.exec_start = rq_clock_task(rq);
/* The running task is never eligible for pushing */
dequeue_pushable_task(rq, p);
set_next_task(rq, rq->curr);
}
static unsigned int get_rr_interval_rt(struct rq *rq, struct task_struct *task)