[PATCH] drm/scheduler: change entities rq even earlier

[Nayan Deshmukh]

On Wed, Aug 8, 2018 at 4:44 PM Christian König <
ckoenig.leichtzumerken at gmail.com> wrote:

> Looks like for correct debugging we need to know the scheduler even
> earlier. So move picking a rq for an entity into job creation.
>
> Signed-off-by: Christian König <christian.koenig at amd.com>
> ---
>  drivers/gpu/drm/scheduler/gpu_scheduler.c | 50
> ++++++++++++++++++++-----------
>  drivers/gpu/drm/scheduler/sched_fence.c   |  2 +-
>  2 files changed, 33 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/gpu/drm/scheduler/gpu_scheduler.c
> b/drivers/gpu/drm/scheduler/gpu_scheduler.c
> index bd7883d1b964..bb2bd4c07e85 100644
> --- a/drivers/gpu/drm/scheduler/gpu_scheduler.c
> +++ b/drivers/gpu/drm/scheduler/gpu_scheduler.c
> @@ -552,6 +552,34 @@ drm_sched_entity_pop_job(struct drm_sched_entity
> *entity)
>         return sched_job;
>  }
>
> +/**
> + * drm_sched_entity_select_rq - select a new rq for the entity
> + *
> + * @entity: scheduler entity
> + *
> + * Check all prerequisites and select a new rq for the entity for load
> + * balancing.
> + */
> +static void drm_sched_entity_select_rq(struct drm_sched_entity *entity)
> +{
> +       struct dma_fence *fence;
> +       struct drm_sched_rq *rq;
> +
> +       if (!spsc_queue_count(&entity->job_queue) == 0 ||
> +           entity->num_rq_list <= 1)
> +               return;
> +
> +       fence = READ_ONCE(entity->last_scheduled);
> +       if (fence && !dma_fence_is_signaled(fence))
> +               return;
> +
> +       rq = drm_sched_entity_get_free_sched(entity);
>
  We can add something like this here:
             if (rq == entity->rq)
                     return;

to avoid redundant reschedules. But then again this is a slight improvement
over the original case so we might as well move it to a different patch.

With or without this change the patch is Reviewed-by: Nayan Deshmukh <
nayan26deshmukh at gmail.com>

> +       spin_lock(&entity->rq_lock);
> +       drm_sched_rq_remove_entity(entity->rq, entity);
> +       entity->rq = rq;
> +       spin_unlock(&entity->rq_lock);
> +}
> +
>  /**
>   * drm_sched_entity_push_job - Submit a job to the entity's job queue
>   *
> @@ -567,25 +595,8 @@ drm_sched_entity_pop_job(struct drm_sched_entity
> *entity)
>  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;
>
> -       first = spsc_queue_count(&entity->job_queue) == 0;
> -       if (first && (entity->num_rq_list > 1)) {
> -               struct dma_fence *fence;
> -
> -               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;
> -       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);
> @@ -790,7 +801,10 @@ int drm_sched_job_init(struct drm_sched_job *job,
>                        struct drm_sched_entity *entity,
>                        void *owner)
>  {
> -       struct drm_gpu_scheduler *sched = entity->rq->sched;
> +       struct drm_gpu_scheduler *sched;
> +
> +       drm_sched_entity_select_rq(entity);
> +       sched = entity->rq->sched;
>
>         job->sched = sched;
>         job->entity = entity;
> diff --git a/drivers/gpu/drm/scheduler/sched_fence.c
> b/drivers/gpu/drm/scheduler/sched_fence.c
> index 6dab18d288d7..4029312fdd81 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 = NULL;
> +       fence->sched = entity->rq->sched;
>         spin_lock_init(&fence->lock);
>
>         seq = atomic_inc_return(&entity->fence_seq);
> --
> 2.14.1
>
>
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