Re: [PATCH 1/2] drm/sched: implement and export drm_sched_pick_best

["Christian König" <christian.koenig@amd.com>]

Am 13.03.20 um 13:05 schrieb Nirmoy Das:
> Refactor drm_sched_entity_get_free_sched() to move the logic of picking
> the least loaded drm scheduler from a drm scheduler list to implement
> drm_sched_pick_best(). This patch also exports drm_sched_pick_best() so
> that it can be utilized by other drm drivers.
>
> Signed-off-by: Nirmoy Das <nirmoy.das@amd.com>
> ---
>   drivers/gpu/drm/scheduler/sched_entity.c | 20 +++-----------
>   drivers/gpu/drm/scheduler/sched_main.c   | 35 ++++++++++++++++++++++++
>   include/drm/gpu_scheduler.h              |  3 ++
>   3 files changed, 42 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/gpu/drm/scheduler/sched_entity.c b/drivers/gpu/drm/scheduler/sched_entity.c
> index d631521a9679..3f6397d60bff 100644
> --- a/drivers/gpu/drm/scheduler/sched_entity.c
> +++ b/drivers/gpu/drm/scheduler/sched_entity.c
> @@ -147,24 +147,12 @@ bool drm_sched_entity_is_ready(struct drm_sched_entity *entity)
>   static struct drm_sched_rq *
>   drm_sched_entity_get_free_sched(struct drm_sched_entity *entity)
>   {
> +	struct drm_gpu_scheduler *sched;
>   	struct drm_sched_rq *rq = NULL;
> -	unsigned int min_jobs = UINT_MAX, num_jobs;
> -	int i;
> -
> -	for (i = 0; i < entity->num_sched_list; ++i) {
> -		struct drm_gpu_scheduler *sched = entity->sched_list[i];
>
> -		if (!entity->sched_list[i]->ready) {
> -			DRM_WARN("sched%s is not ready, skipping", sched->name);
> -			continue;
> -		}
> -
> -		num_jobs = atomic_read(&sched->num_jobs);
> -		if (num_jobs < min_jobs) {
> -			min_jobs = num_jobs;
> -			rq = &entity->sched_list[i]->sched_rq[entity->priority];
> -		}
> -	}
> +	sched = drm_sched_pick_best(entity->sched_list, entity->num_sched_list);
> +	if (sched)
> +		rq = &sched->sched_rq[entity->priority];

Keeping the function just for the two lines doesn't make much sense. 
IIRC it is called only once, just inline there.

>
>   	return rq;
>   }
> diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
> index 3fad5876a13f..d640f4087795 100644
> --- a/drivers/gpu/drm/scheduler/sched_main.c
> +++ b/drivers/gpu/drm/scheduler/sched_main.c
> @@ -705,6 +705,41 @@ drm_sched_get_cleanup_job(struct drm_gpu_scheduler *sched)
>   	return job;
>   }
>
> +/**
> + * drm_sched_pick_best - Get a drm sched from a sched_list with the least load
> + * @sched_list: list of drm_gpu_schedulers
> + * @num_sched_list: number of drm_gpu_schedulers in the sched_list
> + *
> + * Returns pointer of the sched with the least load or NULL if none of the
> + * drm_gpu_schedulers are ready
> + */
> +struct drm_gpu_scheduler *
> +drm_sched_pick_best(struct drm_gpu_scheduler **sched_list,
> +	 	     unsigned int num_sched_list)
> +{
> +	struct drm_gpu_scheduler *sched, *picked_sched = NULL;
> +	unsigned int min_jobs = UINT_MAX, num_jobs;
> +	int i;
> +
> +	for (i = 0; i < num_sched_list; ++i) {
> +		sched = sched_list[i];
> +
> +		if (!sched->ready) {
> +			DRM_WARN("sched%s is not ready, skipping", sched->name);

There is a space missing here between "sched" and "%s". And maybe write 
"scheduler" in the message.

Apart from that looks good of hand,
Christian.

> +			continue;
> +		}
> +
> +		num_jobs = atomic_read(&sched->num_jobs);
> +		if (num_jobs < min_jobs) {
> +			min_jobs = num_jobs;
> +			picked_sched = sched;
> +		}
> +	}
> +
> +	return picked_sched;
> +}
> +EXPORT_SYMBOL(drm_sched_pick_best);
> +
>   /**
>    * drm_sched_blocked - check if the scheduler is blocked
>    *
> diff --git a/include/drm/gpu_scheduler.h b/include/drm/gpu_scheduler.h
> index ae39eacee250..ca6b8b01fac9 100644
> --- a/include/drm/gpu_scheduler.h
> +++ b/include/drm/gpu_scheduler.h
> @@ -341,5 +341,8 @@ void drm_sched_fence_finished(struct drm_sched_fence *fence);
>   unsigned long drm_sched_suspend_timeout(struct drm_gpu_scheduler *sched);
>   void drm_sched_resume_timeout(struct drm_gpu_scheduler *sched,
>   		                unsigned long remaining);
> +struct drm_gpu_scheduler *
> +drm_sched_pick_best(struct drm_gpu_scheduler **sched_list,
> +		    unsigned int num_sched_list);
>
>   #endif
> --
> 2.25.0
>

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