[PATCH 1/2] drm/scheduler: bind job earlier to scheduler

[Nayan Deshmukh]

Hi Christian,

On Mon, Aug 6, 2018 at 5:49 PM Christian König <
ckoenig.leichtzumerken at gmail.com> wrote:

> Update job earlier with the scheduler it is supposed to be scheduled on.
>
> Otherwise we could incorrectly optimize dependencies when moving an
> entity from one scheduler to another.
>
I don't think change is really required, the old code should work fine.
Read below for more comments.


>
> Signed-off-by: Christian König <christian.koenig at amd.com>
> ---
>  drivers/gpu/drm/scheduler/gpu_scheduler.c | 4 ++--
>  drivers/gpu/drm/scheduler/sched_fence.c   | 2 +-
>  2 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/scheduler/gpu_scheduler.c
> b/drivers/gpu/drm/scheduler/gpu_scheduler.c
> index 65078dd3c82c..029863726c99 100644
> --- a/drivers/gpu/drm/scheduler/gpu_scheduler.c
> +++ b/drivers/gpu/drm/scheduler/gpu_scheduler.c
> @@ -533,8 +533,6 @@ drm_sched_entity_pop_job(struct drm_sched_entity
> *entity)
>         if (!sched_job)
>                 return NULL;
>
> -       sched_job->sched = sched;
> -       sched_job->s_fence->sched = sched;
>         while ((entity->dependency = sched->ops->dependency(sched_job,
> entity)))
>
The job should have the correct scheduler before the
sched->oops->dependency() function is called for the first time. Hence I
placed the assignment here.

It might also be that I am missing some case so please let me know if such
a case exists where this might lead to wrong optimization.

Regards,
Nayan

>                 if (drm_sched_entity_add_dependency_cb(entity))
>                         return NULL;
> @@ -581,6 +579,8 @@ void drm_sched_entity_push_job(struct drm_sched_job
> *sched_job,
>                 spin_unlock(&entity->rq_lock);
>         }
>
> +       sched_job->sched = entity->rq->sched;
> +       sched_job->s_fence->sched = entity->rq->sched;
>         trace_drm_sched_job(sched_job, entity);
>         atomic_inc(&entity->rq->sched->num_jobs);
>         WRITE_ONCE(entity->last_user, current->group_leader);
> diff --git a/drivers/gpu/drm/scheduler/sched_fence.c
> b/drivers/gpu/drm/scheduler/sched_fence.c
> index 4029312fdd81..6dab18d288d7 100644
> --- a/drivers/gpu/drm/scheduler/sched_fence.c
> +++ b/drivers/gpu/drm/scheduler/sched_fence.c
> @@ -172,7 +172,7 @@ struct drm_sched_fence *drm_sched_fence_create(struct
> drm_sched_entity *entity,
>                 return NULL;
>
>         fence->owner = owner;
> -       fence->sched = entity->rq->sched;
> +       fence->sched = NULL;
>         spin_lock_init(&fence->lock);
>
>         seq = atomic_inc_return(&entity->fence_seq);
> --
> 2.14.1
>
>
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