[PATCH] drm/scheduler: fix last_scheduled handling

[Nayan Deshmukh]

On Wed, Aug 8, 2018 at 4:36 PM Christian König <
ckoenig.leichtzumerken at gmail.com> wrote:

> Am 08.08.2018 um 12:55 schrieb Nayan Deshmukh:
>
> Hi Christian,
>
> On Wed, Aug 8, 2018 at 4:20 PM Christian König <
> ckoenig.leichtzumerken at gmail.com> wrote:
>
>> Ping, Nayan any comments on that or can I commit it?
>>
>> This is just a stripped down version of my original last_scheduled
>> improvement patch.
>>
>> I had missed the mail yesterday. I was just looking at the code right
> now. The code looks fine but I wanted to run it once before giving it a Rb.
>
> I was wondering why you stripped it down. Was there some problem with the
> previous one?
>
>
> No, not really. But this is a bug fix and bug fixes should be as simple as
> possible.
>
> Improvements should come in separate patches. Didn't thought initially
> that this is actually a fix.
>
> BTW: Another small fix is required, looks like we need the scheduler
> correctly set for debugging even earlier.
>
Yes I saw the mail earlier. I can work on the patch if you have not started
working on it already.

Nayan

>
> Christian.
>
>
> Cheers,
> Nayan
>
>> Christian.
>>
>> Am 07.08.2018 um 14:54 schrieb Christian König:
>> > Make sure we access last_scheduled only after checking that there are no
>> > more jobs on the entity.
>> >
>> > Signed-off-by: Christian König <christian.koenig at amd.com>
>> > ---
>> >   drivers/gpu/drm/scheduler/gpu_scheduler.c | 21 +++++++++++----------
>> >   1 file changed, 11 insertions(+), 10 deletions(-)
>> >
>> > diff --git a/drivers/gpu/drm/scheduler/gpu_scheduler.c
>> b/drivers/gpu/drm/scheduler/gpu_scheduler.c
>> > index 8ee249886473..bd7883d1b964 100644
>> > --- a/drivers/gpu/drm/scheduler/gpu_scheduler.c
>> > +++ b/drivers/gpu/drm/scheduler/gpu_scheduler.c
>> > @@ -568,19 +568,20 @@ void drm_sched_entity_push_job(struct
>> drm_sched_job *sched_job,
>> >                              struct drm_sched_entity *entity)
>> >   {
>> >       struct drm_sched_rq *rq = entity->rq;
>> > -     bool first, reschedule, idle;
>> > +     bool first;
>> >
>> > -     idle = entity->last_scheduled == NULL ||
>> > -             dma_fence_is_signaled(entity->last_scheduled);
>> >       first = spsc_queue_count(&entity->job_queue) == 0;
>> > -     reschedule = idle && first && (entity->num_rq_list > 1);
>> > +     if (first && (entity->num_rq_list > 1)) {
>> > +             struct dma_fence *fence;
>> >
>> > -     if (reschedule) {
>> > -             rq = drm_sched_entity_get_free_sched(entity);
>> > -             spin_lock(&entity->rq_lock);
>> > -             drm_sched_rq_remove_entity(entity->rq, entity);
>> > -             entity->rq = rq;
>> > -             spin_unlock(&entity->rq_lock);
>> > +             fence = READ_ONCE(entity->last_scheduled);
>> > +             if (fence == NULL || dma_fence_is_signaled(fence)) {
>> > +                     rq = drm_sched_entity_get_free_sched(entity);
>> > +                     spin_lock(&entity->rq_lock);
>> > +                     drm_sched_rq_remove_entity(entity->rq, entity);
>> > +                     entity->rq = rq;
>> > +                     spin_unlock(&entity->rq_lock);
>> > +             }
>> >       }
>> >
>> >       sched_job->sched = entity->rq->sched;
>>
>>
>
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