[Intel-xe] [PATCH v7 4/6] drm/sched: Split free_job into own work item

Luben Tuikov luben.tuikov at amd.com
Thu Oct 26 04:38:26 UTC 2023


On 2023-10-26 00:12, Matthew Brost wrote:
> Rather than call free_job and run_job in same work item have a dedicated
> work item for each. This aligns with the design and intended use of work
> queues.
> 
> v2:
>    - Test for DMA_FENCE_FLAG_TIMESTAMP_BIT before setting
>      timestamp in free_job() work item (Danilo)
> v3:
>   - Drop forward dec of drm_sched_select_entity (Boris)
>   - Return in drm_sched_run_job_work if entity NULL (Boris)
> v4:
>   - Replace dequeue with peek and invert logic (Luben)
>   - Wrap to 100 lines (Luben)
>   - Update comments for *_queue / *_queue_if_ready functions (Luben)
> v5:
>   - Drop peek argument, blindly blindly reinit idle (Luben)
>   - s/drm_sched_free_job_queue_if_ready/drm_sched_free_job_queue_if_done (Luben)
>   - Update work_run_job & work_free_job kernel doc (Luben)
> 
> Signed-off-by: Matthew Brost <matthew.brost at intel.com>
> ---
>  drivers/gpu/drm/scheduler/sched_main.c | 241 +++++++++++++++----------
>  include/drm/gpu_scheduler.h            |   8 +-
>  2 files changed, 151 insertions(+), 98 deletions(-)
> 
> diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
> index b22157e920d4..3d89420d4ffb 100644
> --- a/drivers/gpu/drm/scheduler/sched_main.c
> +++ b/drivers/gpu/drm/scheduler/sched_main.c
> @@ -257,12 +257,89 @@ drm_sched_rq_select_entity_fifo(struct drm_sched_rq *rq)
>  
>  /**
>   * drm_sched_run_job_queue - enqueue scheduler submission
> + * drm_sched_run_job_queue - enqueue run-job work
>   * @sched: scheduler instance
>   */
>  static void drm_sched_run_job_queue(struct drm_gpu_scheduler *sched)
>  {
>  	if (!READ_ONCE(sched->pause_submit))
> -		queue_work(sched->submit_wq, &sched->work_submit);
> +		queue_work(sched->submit_wq, &sched->work_run_job);
> +}
> +
> +/**
> + * drm_sched_can_queue -- Can we queue more to the hardware?
> + * @sched: scheduler instance
> + *
> + * Return true if we can push more jobs to the hw, otherwise false.
> + */
> +static bool drm_sched_can_queue(struct drm_gpu_scheduler *sched)
> +{
> +	return atomic_read(&sched->hw_rq_count) <
> +		sched->hw_submission_limit;
> +}
> +
> +/**
> + * drm_sched_select_entity - Select next entity to process
> + *
> + * @sched: scheduler instance
> + *
> + * Returns the entity to process or NULL if none are found.
> + */
> +static struct drm_sched_entity *
> +drm_sched_select_entity(struct drm_gpu_scheduler *sched)
> +{
> +	struct drm_sched_entity *entity;
> +	int i;
> +
> +	if (!drm_sched_can_queue(sched))
> +		return NULL;
> +
> +	/* Kernel run queue has higher priority than normal run queue*/
> +	for (i = sched->num_rqs - 1; i >= DRM_SCHED_PRIORITY_MIN; i--) {
> +		entity = drm_sched_policy == DRM_SCHED_POLICY_FIFO ?
> +			drm_sched_rq_select_entity_fifo(sched->sched_rq[i]) :
> +			drm_sched_rq_select_entity_rr(sched->sched_rq[i]);
> +		if (entity)
> +			break;
> +	}
> +
> +	return entity;
> +}
> +

Could you please rewrite the patch so as to not do the unnecessary move
of the drm_sched_select_entity(). This function has no changes in it,
and this move a few lines up only creates noise, when doing "git blame"
and similar data-mining.

So, just rewrite the patch without moving unchanged code up/down, so
that only the essential differences are shown by git-diff(1). This makes
it easy to review, easy to do data-mining down the road, and so on.

The rest of the patch looks good.

Thanks!

Regards,
Luben

> +/**
> + * drm_sched_run_job_queue_if_ready - enqueue run-job work if ready
> + * @sched: scheduler instance
> + */
> +static void drm_sched_run_job_queue_if_ready(struct drm_gpu_scheduler *sched)
> +{
> +	if (drm_sched_select_entity(sched))
> +		drm_sched_run_job_queue(sched);
> +}
> +
> +/**
> + * drm_sched_free_job_queue - enqueue free-job work
> + * @sched: scheduler instance
> + */
> +static void drm_sched_free_job_queue(struct drm_gpu_scheduler *sched)
> +{
> +	if (!READ_ONCE(sched->pause_submit))
> +		queue_work(sched->submit_wq, &sched->work_free_job);
> +}
> +
> +/**
> + * drm_sched_free_job_queue_if_done - enqueue free-job work if ready
> + * @sched: scheduler instance
> + */
> +static void drm_sched_free_job_queue_if_done(struct drm_gpu_scheduler *sched)
> +{
> +	struct drm_sched_job *job;
> +
> +	spin_lock(&sched->job_list_lock);
> +	job = list_first_entry_or_null(&sched->pending_list,
> +				       struct drm_sched_job, list);
> +	if (job && dma_fence_is_signaled(&job->s_fence->finished))
> +		drm_sched_free_job_queue(sched);
> +	spin_unlock(&sched->job_list_lock);
>  }
>  
>  /**
> @@ -284,7 +361,7 @@ static void drm_sched_job_done(struct drm_sched_job *s_job, int result)
>  	dma_fence_get(&s_fence->finished);
>  	drm_sched_fence_finished(s_fence, result);
>  	dma_fence_put(&s_fence->finished);
> -	drm_sched_run_job_queue(sched);
> +	drm_sched_free_job_queue(sched);
>  }
>  
>  /**
> @@ -550,7 +627,7 @@ void drm_sched_start(struct drm_gpu_scheduler *sched, bool full_recovery)
>  				drm_sched_job_done(s_job, fence->error);
>  			else if (r)
>  				DRM_DEV_ERROR(sched->dev, "fence add callback failed (%d)\n",
> -					  r);
> +					      r);
>  		} else
>  			drm_sched_job_done(s_job, -ECANCELED);
>  	}
> @@ -862,18 +939,6 @@ void drm_sched_job_cleanup(struct drm_sched_job *job)
>  }
>  EXPORT_SYMBOL(drm_sched_job_cleanup);
>  
> -/**
> - * drm_sched_can_queue -- Can we queue more to the hardware?
> - * @sched: scheduler instance
> - *
> - * Return true if we can push more jobs to the hw, otherwise false.
> - */
> -static bool drm_sched_can_queue(struct drm_gpu_scheduler *sched)
> -{
> -	return atomic_read(&sched->hw_rq_count) <
> -		sched->hw_submission_limit;
> -}
> -
>  /**
>   * drm_sched_wakeup_if_can_queue - Wake up the scheduler
>   * @sched: scheduler instance
> @@ -886,34 +951,6 @@ void drm_sched_wakeup_if_can_queue(struct drm_gpu_scheduler *sched)
>  		drm_sched_run_job_queue(sched);
>  }
>  
> -/**
> - * drm_sched_select_entity - Select next entity to process
> - *
> - * @sched: scheduler instance
> - *
> - * Returns the entity to process or NULL if none are found.
> - */
> -static struct drm_sched_entity *
> -drm_sched_select_entity(struct drm_gpu_scheduler *sched)
> -{
> -	struct drm_sched_entity *entity;
> -	int i;
> -
> -	if (!drm_sched_can_queue(sched))
> -		return NULL;
> -
> -	/* Kernel run queue has higher priority than normal run queue*/
> -	for (i = sched->num_rqs - 1; i >= DRM_SCHED_PRIORITY_MIN; i--) {
> -		entity = drm_sched_policy == DRM_SCHED_POLICY_FIFO ?
> -			drm_sched_rq_select_entity_fifo(sched->sched_rq[i]) :
> -			drm_sched_rq_select_entity_rr(sched->sched_rq[i]);
> -		if (entity)
> -			break;
> -	}
> -
> -	return entity;
> -}
> -
>  /**
>   * drm_sched_get_cleanup_job - fetch the next finished job to be destroyed
>   *
> @@ -943,8 +980,10 @@ drm_sched_get_cleanup_job(struct drm_gpu_scheduler *sched)
>  						typeof(*next), list);
>  
>  		if (next) {
> -			next->s_fence->scheduled.timestamp =
> -				dma_fence_timestamp(&job->s_fence->finished);
> +			if (test_bit(DMA_FENCE_FLAG_TIMESTAMP_BIT,
> +				     &next->s_fence->scheduled.flags))
> +				next->s_fence->scheduled.timestamp =
> +					dma_fence_timestamp(&job->s_fence->finished);
>  			/* start TO timer for next job */
>  			drm_sched_start_timeout(sched);
>  		}
> @@ -994,74 +1033,83 @@ drm_sched_pick_best(struct drm_gpu_scheduler **sched_list,
>  EXPORT_SYMBOL(drm_sched_pick_best);
>  
>  /**
> - * drm_sched_main - main scheduler thread
> + * drm_sched_free_job_work - worker to call free_job
>   *
> - * @param: scheduler instance
> + * @w: free job work
>   */
> -static void drm_sched_main(struct work_struct *w)
> +static void drm_sched_free_job_work(struct work_struct *w)
>  {
>  	struct drm_gpu_scheduler *sched =
> -		container_of(w, struct drm_gpu_scheduler, work_submit);
> -	struct drm_sched_entity *entity;
> +		container_of(w, struct drm_gpu_scheduler, work_free_job);
>  	struct drm_sched_job *cleanup_job;
> -	int r;
>  
>  	if (READ_ONCE(sched->pause_submit))
>  		return;
>  
>  	cleanup_job = drm_sched_get_cleanup_job(sched);
> -	entity = drm_sched_select_entity(sched);
> -
> -	if (!entity && !cleanup_job)
> -		return;	/* No more work */
> -
> -	if (cleanup_job)
> +	if (cleanup_job) {
>  		sched->ops->free_job(cleanup_job);
>  
> -	if (entity) {
> -		struct dma_fence *fence;
> -		struct drm_sched_fence *s_fence;
> -		struct drm_sched_job *sched_job;
> -
> -		sched_job = drm_sched_entity_pop_job(entity);
> -		if (!sched_job) {
> -			complete_all(&entity->entity_idle);
> -			if (!cleanup_job)
> -				return;	/* No more work */
> -			goto again;
> -		}
> +		drm_sched_free_job_queue_if_done(sched);
> +		drm_sched_run_job_queue_if_ready(sched);
> +	}
> +}
>  
> -		s_fence = sched_job->s_fence;
> +/**
> + * drm_sched_run_job_work - worker to call run_job
> + *
> + * @w: run job work
> + */
> +static void drm_sched_run_job_work(struct work_struct *w)
> +{
> +	struct drm_gpu_scheduler *sched =
> +		container_of(w, struct drm_gpu_scheduler, work_run_job);
> +	struct drm_sched_entity *entity;
> +	struct dma_fence *fence;
> +	struct drm_sched_fence *s_fence;
> +	struct drm_sched_job *sched_job;
> +	int r;
>  
> -		atomic_inc(&sched->hw_rq_count);
> -		drm_sched_job_begin(sched_job);
> +	if (READ_ONCE(sched->pause_submit))
> +		return;
>  
> -		trace_drm_run_job(sched_job, entity);
> -		fence = sched->ops->run_job(sched_job);
> +	entity = drm_sched_select_entity(sched);
> +	if (!entity)
> +		return;
> +
> +	sched_job = drm_sched_entity_pop_job(entity);
> +	if (!sched_job) {
>  		complete_all(&entity->entity_idle);
> -		drm_sched_fence_scheduled(s_fence, fence);
> +		return;	/* No more work */
> +	}
>  
> -		if (!IS_ERR_OR_NULL(fence)) {
> -			/* Drop for original kref_init of the fence */
> -			dma_fence_put(fence);
> +	s_fence = sched_job->s_fence;
>  
> -			r = dma_fence_add_callback(fence, &sched_job->cb,
> -						   drm_sched_job_done_cb);
> -			if (r == -ENOENT)
> -				drm_sched_job_done(sched_job, fence->error);
> -			else if (r)
> -				DRM_DEV_ERROR(sched->dev, "fence add callback failed (%d)\n",
> -					  r);
> -		} else {
> -			drm_sched_job_done(sched_job, IS_ERR(fence) ?
> -					   PTR_ERR(fence) : 0);
> -		}
> +	atomic_inc(&sched->hw_rq_count);
> +	drm_sched_job_begin(sched_job);
>  
> -		wake_up(&sched->job_scheduled);
> +	trace_drm_run_job(sched_job, entity);
> +	fence = sched->ops->run_job(sched_job);
> +	complete_all(&entity->entity_idle);
> +	drm_sched_fence_scheduled(s_fence, fence);
> +
> +	if (!IS_ERR_OR_NULL(fence)) {
> +		/* Drop for original kref_init of the fence */
> +		dma_fence_put(fence);
> +
> +		r = dma_fence_add_callback(fence, &sched_job->cb,
> +					   drm_sched_job_done_cb);
> +		if (r == -ENOENT)
> +			drm_sched_job_done(sched_job, fence->error);
> +		else if (r)
> +			DRM_DEV_ERROR(sched->dev, "fence add callback failed (%d)\n", r);
> +	} else {
> +		drm_sched_job_done(sched_job, IS_ERR(fence) ?
> +				   PTR_ERR(fence) : 0);
>  	}
>  
> -again:
> -	drm_sched_run_job_queue(sched);
> +	wake_up(&sched->job_scheduled);
> +	drm_sched_run_job_queue_if_ready(sched);
>  }
>  
>  /**
> @@ -1146,7 +1194,8 @@ int drm_sched_init(struct drm_gpu_scheduler *sched,
>  	spin_lock_init(&sched->job_list_lock);
>  	atomic_set(&sched->hw_rq_count, 0);
>  	INIT_DELAYED_WORK(&sched->work_tdr, drm_sched_job_timedout);
> -	INIT_WORK(&sched->work_submit, drm_sched_main);
> +	INIT_WORK(&sched->work_run_job, drm_sched_run_job_work);
> +	INIT_WORK(&sched->work_free_job, drm_sched_free_job_work);
>  	atomic_set(&sched->_score, 0);
>  	atomic64_set(&sched->job_id_count, 0);
>  	sched->pause_submit = false;
> @@ -1273,7 +1322,8 @@ EXPORT_SYMBOL(drm_sched_wqueue_ready);
>  void drm_sched_wqueue_stop(struct drm_gpu_scheduler *sched)
>  {
>  	WRITE_ONCE(sched->pause_submit, true);
> -	cancel_work_sync(&sched->work_submit);
> +	cancel_work_sync(&sched->work_run_job);
> +	cancel_work_sync(&sched->work_free_job);
>  }
>  EXPORT_SYMBOL(drm_sched_wqueue_stop);
>  
> @@ -1285,6 +1335,7 @@ EXPORT_SYMBOL(drm_sched_wqueue_stop);
>  void drm_sched_wqueue_start(struct drm_gpu_scheduler *sched)
>  {
>  	WRITE_ONCE(sched->pause_submit, false);
> -	queue_work(sched->submit_wq, &sched->work_submit);
> +	queue_work(sched->submit_wq, &sched->work_run_job);
> +	queue_work(sched->submit_wq, &sched->work_free_job);
>  }
>  EXPORT_SYMBOL(drm_sched_wqueue_start);
> diff --git a/include/drm/gpu_scheduler.h b/include/drm/gpu_scheduler.h
> index 1d52b8bbb06c..37749f561866 100644
> --- a/include/drm/gpu_scheduler.h
> +++ b/include/drm/gpu_scheduler.h
> @@ -480,9 +480,10 @@ struct drm_sched_backend_ops {
>   *                 finished.
>   * @hw_rq_count: the number of jobs currently in the hardware queue.
>   * @job_id_count: used to assign unique id to the each job.
> - * @submit_wq: workqueue used to queue @work_submit
> + * @submit_wq: workqueue used to queue @work_run_job and @work_free_job
>   * @timeout_wq: workqueue used to queue @work_tdr
> - * @work_submit: schedules jobs and cleans up entities
> + * @work_run_job: work which calls run_job op of each scheduler.
> + * @work_free_job: work which calls free_job op of each scheduler.
>   * @work_tdr: schedules a delayed call to @drm_sched_job_timedout after the
>   *            timeout interval is over.
>   * @pending_list: the list of jobs which are currently in the job queue.
> @@ -511,7 +512,8 @@ struct drm_gpu_scheduler {
>  	atomic64_t			job_id_count;
>  	struct workqueue_struct		*submit_wq;
>  	struct workqueue_struct		*timeout_wq;
> -	struct work_struct		work_submit;
> +	struct work_struct		work_run_job;
> +	struct work_struct		work_free_job;
>  	struct delayed_work		work_tdr;
>  	struct list_head		pending_list;
>  	spinlock_t			job_list_lock;



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