Re: [PATCH 13/23] sched,ion: Convert to sched_set_normal()
From: Peter Zijlstra
Date: Wed Apr 22 2020 - 09:29:59 EST
On Wed, Apr 22, 2020 at 03:21:45PM +0200, Vincent Guittot wrote:
> On Wed, 22 Apr 2020 at 13:29, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
> >
> > In an attempt to take away sched_setscheduler() from modules, change
> > this into sched_set_normal(.nice = 19).
> >
> > Cc: john.stultz@xxxxxxxxxx
> > Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
> > Reviewed-by: Ingo Molnar <mingo@xxxxxxxxxx>
> > ---
> > drivers/staging/android/ion/ion_heap.c | 3 ---
> > 1 file changed, 3 deletions(-)
> >
> > --- a/drivers/staging/android/ion/ion_heap.c
> > +++ b/drivers/staging/android/ion/ion_heap.c
> > @@ -244,8 +244,6 @@ static int ion_heap_deferred_free(void *
> >
> > int ion_heap_init_deferred_free(struct ion_heap *heap)
> > {
> > - struct sched_param param = { .sched_priority = 0 };
> > -
> > INIT_LIST_HEAD(&heap->free_list);
> > init_waitqueue_head(&heap->waitqueue);
> > heap->task = kthread_run(ion_heap_deferred_free, heap,
> > @@ -255,7 +253,7 @@ int ion_heap_init_deferred_free(struct i
> > __func__);
> > return PTR_ERR_OR_ZERO(heap->task);
> > }
> > - sched_setscheduler(heap->task, SCHED_IDLE, ¶m);
> > + sched_set_normal(heap->task, 19);
>
> Would it make sense to have a sched_set_idle(task) to enable kernel
> setting SCHED_IDLE task ?
>
> SCHED_NORMAL w/ nice 19 and SCHED_IDLE tasks are not treated in the
> same way when checking for preemption at wakeup
Yeah, but does it really matter? I did indeed consider it, but got
lazy. Is there a definite need for IDLE?