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    SubjectRe: [RFC][PATCH 04/13] sched/{rt,deadline}: Fix set_next_task vs pick_next_task
    Hi,

    On 26/07/19 16:54, Peter Zijlstra wrote:
    > Because pick_next_task() implies set_curr_task() and some of the
    > details haven't matter too much, some of what _should_ be in
    > set_curr_task() ended up in pick_next_task, correct this.
    >
    > This prepares the way for a pick_next_task() variant that does not
    > affect the current state; allowing remote picking.
    >
    > Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
    > ---
    > kernel/sched/deadline.c | 23 ++++++++++++-----------
    > kernel/sched/rt.c | 27 ++++++++++++++-------------
    > 2 files changed, 26 insertions(+), 24 deletions(-)
    >
    > --- a/kernel/sched/deadline.c
    > +++ b/kernel/sched/deadline.c
    > @@ -1694,12 +1694,21 @@ static void start_hrtick_dl(struct rq *r
    > }
    > #endif
    >
    > -static inline void set_next_task(struct rq *rq, struct task_struct *p)
    > +static void set_next_task_dl(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);
    > +
    > + if (hrtick_enabled(rq))
    > + start_hrtick_dl(rq, p);
    > +
    > + if (rq->curr->sched_class != &dl_sched_class)
    > + update_dl_rq_load_avg(rq_clock_pelt(rq), rq, 0);
    > +
    > + if (rq->curr != p)
    > + deadline_queue_push_tasks(rq);

    It's a minor thing, but I was wondering why you added the check on curr.
    deadline_queue_push_tasks() already checks if are there pushable tasks,
    plus curr can still be of a different class at this point?

    Thanks,

    Juri

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