Re: [PATCH 1/4] drm/sched: Add job popping API

[Danilo Krummrich <dakr@kernel.org>]

On Mon, Jan 20, 2025 at 04:52:37PM +0000, Tvrtko Ursulin wrote:
> Idea is to add a helper for popping jobs from the entity with the goal
> of making amdgpu use it in the next patch. That way amdgpu will decouple
> itself a tiny bit more from scheduler implementation details.

I object to adding this function if it's *only* used for something that looks
like an abuse of the API by amdgpu. Let's not make that more convenient.

> 
> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
> Cc: Christian König <christian.koenig@amd.com>
> Cc: Danilo Krummrich <dakr@kernel.org>
> Cc: Matthew Brost <matthew.brost@intel.com>
> Cc: Philipp Stanner <phasta@kernel.org>
> ---
>  drivers/gpu/drm/scheduler/sched_entity.c |  2 +-
>  include/drm/gpu_scheduler.h              | 21 +++++++++++++++++++++
>  2 files changed, 22 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/scheduler/sched_entity.c b/drivers/gpu/drm/scheduler/sched_entity.c
> index 69bcf0e99d57..7c0d266a89ef 100644
> --- a/drivers/gpu/drm/scheduler/sched_entity.c
> +++ b/drivers/gpu/drm/scheduler/sched_entity.c
> @@ -255,7 +255,7 @@ static void drm_sched_entity_kill(struct drm_sched_entity *entity)
>  	/* The entity is guaranteed to not be used by the scheduler */
>  	prev = rcu_dereference_check(entity->last_scheduled, true);
>  	dma_fence_get(prev);
> -	while ((job = to_drm_sched_job(spsc_queue_pop(&entity->job_queue)))) {
> +	while ((job = __drm_sched_entity_pop_job(entity))) {
>  		struct drm_sched_fence *s_fence = job->s_fence;
>  
>  		dma_fence_get(&s_fence->finished);
> diff --git a/include/drm/gpu_scheduler.h b/include/drm/gpu_scheduler.h
> index a0ff08123f07..092242f2464f 100644
> --- a/include/drm/gpu_scheduler.h
> +++ b/include/drm/gpu_scheduler.h
> @@ -611,6 +611,27 @@ void drm_sched_entity_set_priority(struct drm_sched_entity *entity,
>  bool drm_sched_entity_is_ready(struct drm_sched_entity *entity);
>  int drm_sched_entity_error(struct drm_sched_entity *entity);
>  
> +/**
> + * __drm_sched_entity_pop_job - Low level helper for popping queued jobs
> + *
> + * @entity: scheduler entity
> + *
> + * Low level helper for popping queued jobs. Drivers should not use it.
> + *
> + * Returns the job dequeued or NULL.
> + */
> +static inline struct drm_sched_job *
> +__drm_sched_entity_pop_job(struct drm_sched_entity *entity)
> +{
> +	struct spsc_node *node;
> +
> +	node = spsc_queue_pop(&entity->job_queue);
> +	if (!node)
> +		return NULL;
> +
> +	return container_of(node, struct drm_sched_job, queue_node);
> +}
> +
>  struct drm_sched_fence *drm_sched_fence_alloc(
>  	struct drm_sched_entity *s_entity, void *owner);
>  void drm_sched_fence_init(struct drm_sched_fence *fence,
> -- 
> 2.47.1
>