Re: [PATCH] drm/sched: Convert the GPU scheduler to variable number of run-queues

Danilo Krummrich <dakr@xxxxxxxxxx> · Tue, 31 Oct 2023 14:33:25 +0100

On 10/26/23 19:25, Luben Tuikov wrote:
On 2023-10-26 12:39, Danilo Krummrich wrote:
On 10/23/23 05:22, Luben Tuikov wrote:
The GPU scheduler has now a variable number of run-queues, which are set up at
drm_sched_init() time. This way, each driver announces how many run-queues it
requires (supports) per each GPU scheduler it creates. Note, that run-queues
correspond to scheduler "priorities", thus if the number of run-queues is set
to 1 at drm_sched_init(), then that scheduler supports a single run-queue,
i.e. single "priority". If a driver further sets a single entity per
run-queue, then this creates a 1-to-1 correspondence between a scheduler and
a scheduled entity.

Generally, I'm fine with this patch and how it replaces / generalizes the single
entity approach.

Great!

However, I'm not quite sure how to properly use this. What is a driver supposed to
do, which previously took advantage of DRM_SCHED_POLICY_SINGLE_ENTITY?

Is it supposed to call drm_sched_init() with num_rqs=1? If so, what's the correct way

Yes, you call drm_sched_init() with num_rqs set to 1.

to initialize the drm_sched_entity then? Calling drm_sched_entity_init() with priority=0?

Yes, with priority set to 0.

One unfortunate fact I noticed when doing this patch is that the numerical values
assigned to enum drm_sched_priority is that the names to values are upside down.
Instead of min being 0, normal:1, high:2, kernel:3, it should've been kernel:0 (highest),
high:1, normal:2, low:4, and so on.

The reason for this is absolutely clear: if you had a single priority, it would be
0, the kernel, one, highest one. This is similar to how lanes in a highway are counted:
you always have lane 1. Similarly to nice(1) and kernel priorities...

Any other priority consequently faults in drm_sched_job_arm().

drm_sched_job_arm() faults on !ENTITY, but the "priority" is just
assigned to s_priority:
	job->s_priority = entity->priority;


While I might sound like a broken record (sorry for that), I really think everything
related to Matt's series needs documentation, as in:

Yes, I agree.

Great! Do you plan to send a subsequent patch adding some documentation for this one? I
think it'd be good to get all the above documented.

  
- What is the typical application of the single entity / variable run queue design?
    How do drivers make use of it?

I believe most drivers in the future, would want to have a single sched_rq (i.e. single
"priority", and then would tack a single entity to this, and then do prioritization
internally in their firmware/hardware.

- How to tear down a scheduler instance properly?
- Motivation and implications of the workqueue topology (default workqueue, external
    driver workqueue, free job work, run job work, etc.).

But also the existing scheduler infrastructure requires more documentation.

The scheduler barely has some documentation to describe its basic topology of
struct drm_gpu_scheduler, struct drm_sched_entity and struct drm_sched_job.
Plus a few hints regarding run queue priorities, which, with this patch, seem to be
(partially) out-dated or at least incomplete.

I think Sima also mentioned that we really need to put some efforts here. [1]

Yes, that's true.

Regards,
Luben


- Danilo

[1] https://lore.kernel.org/all/20231017150958.838613-1-matthew.brost@xxxxxxxxx/T/#m330335b44bdb7ae93ac6ebdedd65706df5a0f03d


Cc: Lucas Stach <l.stach@xxxxxxxxxxxxxx>
Cc: Russell King <linux+etnaviv@xxxxxxxxxxxxxxx>
Cc: Qiang Yu <yuq825@xxxxxxxxx>
Cc: Rob Clark <robdclark@xxxxxxxxx>
Cc: Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx>
Cc: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
Cc: Danilo Krummrich <dakr@xxxxxxxxxx>
Cc: Matthew Brost <matthew.brost@xxxxxxxxx>
Cc: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx>
Cc: Alex Deucher <alexander.deucher@xxxxxxx>
Cc: Christian König <christian.koenig@xxxxxxx>
Cc: Emma Anholt <emma@xxxxxxxxxx>
Cc: etnaviv@xxxxxxxxxxxxxxxxxxxxx
Cc: lima@xxxxxxxxxxxxxxxxxxxxx
Cc: linux-arm-msm@xxxxxxxxxxxxxxx
Cc: freedreno@xxxxxxxxxxxxxxxxxxxxx
Cc: nouveau@xxxxxxxxxxxxxxxxxxxxx
Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Luben Tuikov <luben.tuikov@xxxxxxx>
---
   drivers/gpu/drm/amd/amdgpu/amdgpu_device.c |  1 +
   drivers/gpu/drm/amd/amdgpu/amdgpu_job.c    |  4 +-
   drivers/gpu/drm/etnaviv/etnaviv_sched.c    |  1 +
   drivers/gpu/drm/lima/lima_sched.c          |  4 +-
   drivers/gpu/drm/msm/msm_ringbuffer.c       |  5 +-
   drivers/gpu/drm/nouveau/nouveau_sched.c    |  1 +
   drivers/gpu/drm/panfrost/panfrost_job.c    |  1 +
   drivers/gpu/drm/scheduler/sched_entity.c   | 18 +++++-
   drivers/gpu/drm/scheduler/sched_main.c     | 74 ++++++++++++++++++----
   drivers/gpu/drm/v3d/v3d_sched.c            |  5 ++
   include/drm/gpu_scheduler.h                |  9 ++-
   11 files changed, 98 insertions(+), 25 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index 2b8356699f235d..251995a90bbe69 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -2280,6 +2280,7 @@ static int amdgpu_device_init_schedulers(struct amdgpu_device *adev)
   		}
   
   		r = drm_sched_init(&ring->sched, &amdgpu_sched_ops,
+				   DRM_SCHED_PRIORITY_COUNT,
   				   ring->num_hw_submission, 0,
   				   timeout, adev->reset_domain->wq,
   				   ring->sched_score, ring->name,
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
index 78476bc75b4e1d..1f357198533f3e 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
@@ -325,8 +325,8 @@ void amdgpu_job_stop_all_jobs_on_sched(struct drm_gpu_scheduler *sched)
   	int i;
   
   	/* Signal all jobs not yet scheduled */
-	for (i = DRM_SCHED_PRIORITY_COUNT - 1; i >= DRM_SCHED_PRIORITY_MIN; i--) {
-		struct drm_sched_rq *rq = &sched->sched_rq[i];
+	for (i = sched->num_rqs - 1; i >= DRM_SCHED_PRIORITY_MIN; i--) {
+		struct drm_sched_rq *rq = sched->sched_rq[i];
   		spin_lock(&rq->lock);
   		list_for_each_entry(s_entity, &rq->entities, list) {
   			while ((s_job = to_drm_sched_job(spsc_queue_pop(&s_entity->job_queue)))) {
diff --git a/drivers/gpu/drm/etnaviv/etnaviv_sched.c b/drivers/gpu/drm/etnaviv/etnaviv_sched.c
index 345fec6cb1a4c1..9b79f218e21afc 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_sched.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_sched.c
@@ -135,6 +135,7 @@ int etnaviv_sched_init(struct etnaviv_gpu *gpu)
   	int ret;
   
   	ret = drm_sched_init(&gpu->sched, &etnaviv_sched_ops,
+			     DRM_SCHED_PRIORITY_COUNT,
   			     etnaviv_hw_jobs_limit, etnaviv_job_hang_limit,
   			     msecs_to_jiffies(500), NULL, NULL,
   			     dev_name(gpu->dev), gpu->dev);
diff --git a/drivers/gpu/drm/lima/lima_sched.c b/drivers/gpu/drm/lima/lima_sched.c
index ffd91a5ee29901..295f0353a02e58 100644
--- a/drivers/gpu/drm/lima/lima_sched.c
+++ b/drivers/gpu/drm/lima/lima_sched.c
@@ -488,7 +488,9 @@ int lima_sched_pipe_init(struct lima_sched_pipe *pipe, const char *name)
   
   	INIT_WORK(&pipe->recover_work, lima_sched_recover_work);
   
-	return drm_sched_init(&pipe->base, &lima_sched_ops, 1,
+	return drm_sched_init(&pipe->base, &lima_sched_ops,
+			      DRM_SCHED_PRIORITY_COUNT,
+			      1,
   			      lima_job_hang_limit,
   			      msecs_to_jiffies(timeout), NULL,
   			      NULL, name, pipe->ldev->dev);
diff --git a/drivers/gpu/drm/msm/msm_ringbuffer.c b/drivers/gpu/drm/msm/msm_ringbuffer.c
index 40c0bc35a44cee..95257ab0185dc4 100644
--- a/drivers/gpu/drm/msm/msm_ringbuffer.c
+++ b/drivers/gpu/drm/msm/msm_ringbuffer.c
@@ -95,8 +95,9 @@ struct msm_ringbuffer *msm_ringbuffer_new(struct msm_gpu *gpu, int id,
   	sched_timeout = MAX_SCHEDULE_TIMEOUT;
   
   	ret = drm_sched_init(&ring->sched, &msm_sched_ops,
-			num_hw_submissions, 0, sched_timeout,
-			NULL, NULL, to_msm_bo(ring->bo)->name, gpu->dev->dev);
+			     DRM_SCHED_PRIORITY_COUNT,
+			     num_hw_submissions, 0, sched_timeout,
+			     NULL, NULL, to_msm_bo(ring->bo)->name, gpu->dev->dev);
   	if (ret) {
   		goto fail;
   	}
diff --git a/drivers/gpu/drm/nouveau/nouveau_sched.c b/drivers/gpu/drm/nouveau/nouveau_sched.c
index 3b7ea522122605..7c376c4ccdcf9b 100644
--- a/drivers/gpu/drm/nouveau/nouveau_sched.c
+++ b/drivers/gpu/drm/nouveau/nouveau_sched.c
@@ -436,6 +436,7 @@ int nouveau_sched_init(struct nouveau_drm *drm)
   		return -ENOMEM;
   
   	return drm_sched_init(sched, &nouveau_sched_ops,
+			      DRM_SCHED_PRIORITY_COUNT,
   			      NOUVEAU_SCHED_HW_SUBMISSIONS, 0, job_hang_limit,
   			      NULL, NULL, "nouveau_sched", drm->dev->dev);
   }
diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c b/drivers/gpu/drm/panfrost/panfrost_job.c
index a8b4827dc42586..95510d481fab3a 100644
--- a/drivers/gpu/drm/panfrost/panfrost_job.c
+++ b/drivers/gpu/drm/panfrost/panfrost_job.c
@@ -832,6 +832,7 @@ int panfrost_job_init(struct panfrost_device *pfdev)
   
   		ret = drm_sched_init(&js->queue[j].sched,
   				     &panfrost_sched_ops,
+				     DRM_SCHED_PRIORITY_COUNT,
   				     nentries, 0,
   				     msecs_to_jiffies(JOB_TIMEOUT_MS),
   				     pfdev->reset.wq,
diff --git a/drivers/gpu/drm/scheduler/sched_entity.c b/drivers/gpu/drm/scheduler/sched_entity.c
index a42763e1429dc1..409e4256f6e7d6 100644
--- a/drivers/gpu/drm/scheduler/sched_entity.c
+++ b/drivers/gpu/drm/scheduler/sched_entity.c
@@ -75,8 +75,20 @@ int drm_sched_entity_init(struct drm_sched_entity *entity,
   	RCU_INIT_POINTER(entity->last_scheduled, NULL);
   	RB_CLEAR_NODE(&entity->rb_tree_node);
   
-	if(num_sched_list)
-		entity->rq = &sched_list[0]->sched_rq[entity->priority];
+	if (!sched_list[0]->sched_rq) {
+		/* Warn drivers not to do this and to fix their DRM
+		 * calling order.
+		 */
+		pr_warn("%s: called with uninitialized scheduler\n", __func__);
+	} else if (num_sched_list) {
+		/* The "priority" of an entity cannot exceed the number
+		 * of run-queues of a scheduler.
+		 */
+		if (entity->priority >= sched_list[0]->num_rqs)
+			entity->priority = max_t(u32, sched_list[0]->num_rqs,
+						 DRM_SCHED_PRIORITY_MIN);
+		entity->rq = sched_list[0]->sched_rq[entity->priority];
+	}
   
   	init_completion(&entity->entity_idle);
   
@@ -533,7 +545,7 @@ void drm_sched_entity_select_rq(struct drm_sched_entity *entity)
   
   	spin_lock(&entity->rq_lock);
   	sched = drm_sched_pick_best(entity->sched_list, entity->num_sched_list);
-	rq = sched ? &sched->sched_rq[entity->priority] : NULL;
+	rq = sched ? sched->sched_rq[entity->priority] : NULL;
   	if (rq != entity->rq) {
   		drm_sched_rq_remove_entity(entity->rq, entity);
   		entity->rq = rq;
diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
index 5a3a622fc672f3..99797a8c836ac7 100644
--- a/drivers/gpu/drm/scheduler/sched_main.c
+++ b/drivers/gpu/drm/scheduler/sched_main.c
@@ -632,8 +632,14 @@ int drm_sched_job_init(struct drm_sched_job *job,
   		       struct drm_sched_entity *entity,
   		       void *owner)
   {
-	if (!entity->rq)
+	if (!entity->rq) {
+		/* This will most likely be followed by missing frames
+		 * or worse--a blank screen--leave a trail in the
+		 * logs, so this can be debugged easier.
+		 */
+		drm_err(job->sched, "%s: entity has no rq!\n", __func__);
   		return -ENOENT;
+	}
   
   	job->entity = entity;
   	job->s_fence = drm_sched_fence_alloc(entity, owner);
@@ -671,7 +677,7 @@ void drm_sched_job_arm(struct drm_sched_job *job)
   	sched = entity->rq->sched;
   
   	job->sched = sched;
-	job->s_priority = entity->rq - sched->sched_rq;
+	job->s_priority = entity->priority;
   	job->id = atomic64_inc_return(&sched->job_id_count);
   
   	drm_sched_fence_init(job->s_fence, job->entity);
@@ -888,10 +894,10 @@ drm_sched_select_entity(struct drm_gpu_scheduler *sched)
   		return NULL;
   
   	/* Kernel run queue has higher priority than normal run queue*/
-	for (i = DRM_SCHED_PRIORITY_COUNT - 1; i >= DRM_SCHED_PRIORITY_MIN; i--) {
+	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]);
+			drm_sched_rq_select_entity_fifo(sched->sched_rq[i]) :
+			drm_sched_rq_select_entity_rr(sched->sched_rq[i]);
   		if (entity)
   			break;
   	}
@@ -1071,6 +1077,7 @@ static int drm_sched_main(void *param)
    *
    * @sched: scheduler instance
    * @ops: backend operations for this scheduler
+ * @num_rqs: number of runqueues, one for each priority, up to DRM_SCHED_PRIORITY_COUNT
    * @hw_submission: number of hw submissions that can be in flight
    * @hang_limit: number of times to allow a job to hang before dropping it
    * @timeout: timeout value in jiffies for the scheduler
@@ -1084,11 +1091,12 @@ static int drm_sched_main(void *param)
    */
   int drm_sched_init(struct drm_gpu_scheduler *sched,
   		   const struct drm_sched_backend_ops *ops,
-		   unsigned hw_submission, unsigned hang_limit,
+		   u32 num_rqs, uint32_t hw_submission, unsigned int hang_limit,
   		   long timeout, struct workqueue_struct *timeout_wq,
   		   atomic_t *score, const char *name, struct device *dev)
   {
   	int i, ret;
+
   	sched->ops = ops;
   	sched->hw_submission_limit = hw_submission;
   	sched->name = name;
@@ -1097,8 +1105,36 @@ int drm_sched_init(struct drm_gpu_scheduler *sched,
   	sched->hang_limit = hang_limit;
   	sched->score = score ? score : &sched->_score;
   	sched->dev = dev;
-	for (i = DRM_SCHED_PRIORITY_MIN; i < DRM_SCHED_PRIORITY_COUNT; i++)
-		drm_sched_rq_init(sched, &sched->sched_rq[i]);
+
+	if (num_rqs > DRM_SCHED_PRIORITY_COUNT) {
+		/* This is a gross violation--tell drivers what the  problem is.
+		 */
+		drm_err(sched, "%s: num_rqs cannot be greater than DRM_SCHED_PRIORITY_COUNT\n",
+			__func__);
+		return -EINVAL;
+	} else if (sched->sched_rq) {
+		/* Not an error, but warn anyway so drivers can
+		 * fine-tune their DRM calling order, and return all
+		 * is good.
+		 */
+		drm_warn(sched, "%s: scheduler already initialized!\n", __func__);
+		return 0;
+	}
+
+	sched->sched_rq = kmalloc_array(num_rqs, sizeof(*sched->sched_rq),
+					GFP_KERNEL | __GFP_ZERO);
+	if (!sched->sched_rq) {
+		drm_err(sched, "%s: out of memory for sched_rq\n", __func__);
+		return -ENOMEM;
+	}
+	sched->num_rqs = num_rqs;
+	ret = -ENOMEM;
+	for (i = DRM_SCHED_PRIORITY_MIN; i < sched->num_rqs; i++) {
+		sched->sched_rq[i] = kzalloc(sizeof(*sched->sched_rq[i]), GFP_KERNEL);
+		if (!sched->sched_rq[i])
+			goto Out_unroll;
+		drm_sched_rq_init(sched, sched->sched_rq[i]);
+	}
   
   	init_waitqueue_head(&sched->wake_up_worker);
   	init_waitqueue_head(&sched->job_scheduled);
@@ -1115,11 +1151,18 @@ int drm_sched_init(struct drm_gpu_scheduler *sched,
   		ret = PTR_ERR(sched->thread);
   		sched->thread = NULL;
   		DRM_DEV_ERROR(sched->dev, "Failed to create scheduler for %s.\n", name);
-		return ret;
+		goto Out_unroll;
   	}
   
   	sched->ready = true;
   	return 0;
+Out_unroll:
+	for (--i ; i >= DRM_SCHED_PRIORITY_MIN; i--)
+		kfree(sched->sched_rq[i]);
+	kfree(sched->sched_rq);
+	sched->sched_rq = NULL;
+	drm_err(sched, "%s: Failed to setup GPU scheduler--out of memory\n", __func__);
+	return ret;
   }
   EXPORT_SYMBOL(drm_sched_init);
   
@@ -1138,8 +1181,8 @@ void drm_sched_fini(struct drm_gpu_scheduler *sched)
   	if (sched->thread)
   		kthread_stop(sched->thread);
   
-	for (i = DRM_SCHED_PRIORITY_COUNT - 1; i >= DRM_SCHED_PRIORITY_MIN; i--) {
-		struct drm_sched_rq *rq = &sched->sched_rq[i];
+	for (i = sched->num_rqs - 1; i >= DRM_SCHED_PRIORITY_MIN; i--) {
+		struct drm_sched_rq *rq = sched->sched_rq[i];
   
   		spin_lock(&rq->lock);
   		list_for_each_entry(s_entity, &rq->entities, list)
@@ -1150,7 +1193,7 @@ void drm_sched_fini(struct drm_gpu_scheduler *sched)
   			 */
   			s_entity->stopped = true;
   		spin_unlock(&rq->lock);
-
+		kfree(sched->sched_rq[i]);
   	}
   
   	/* Wakeup everyone stuck in drm_sched_entity_flush for this scheduler */
@@ -1160,6 +1203,8 @@ void drm_sched_fini(struct drm_gpu_scheduler *sched)
   	cancel_delayed_work_sync(&sched->work_tdr);
   
   	sched->ready = false;
+	kfree(sched->sched_rq);
+	sched->sched_rq = NULL;
   }
   EXPORT_SYMBOL(drm_sched_fini);
   
@@ -1186,9 +1231,10 @@ void drm_sched_increase_karma(struct drm_sched_job *bad)
   	if (bad->s_priority != DRM_SCHED_PRIORITY_KERNEL) {
   		atomic_inc(&bad->karma);
   
-		for (i = DRM_SCHED_PRIORITY_MIN; i < DRM_SCHED_PRIORITY_KERNEL;
+		for (i = DRM_SCHED_PRIORITY_MIN;
+		     i < min_t(typeof(sched->num_rqs), sched->num_rqs, DRM_SCHED_PRIORITY_KERNEL);
   		     i++) {
-			struct drm_sched_rq *rq = &sched->sched_rq[i];
+			struct drm_sched_rq *rq = sched->sched_rq[i];
   
   			spin_lock(&rq->lock);
   			list_for_each_entry_safe(entity, tmp, &rq->entities, list) {
diff --git a/drivers/gpu/drm/v3d/v3d_sched.c b/drivers/gpu/drm/v3d/v3d_sched.c
index 06238e6d7f5cda..038e1ae589c718 100644
--- a/drivers/gpu/drm/v3d/v3d_sched.c
+++ b/drivers/gpu/drm/v3d/v3d_sched.c
@@ -389,6 +389,7 @@ v3d_sched_init(struct v3d_dev *v3d)
   
   	ret = drm_sched_init(&v3d->queue[V3D_BIN].sched,
   			     &v3d_bin_sched_ops,
+			     DRM_SCHED_PRIORITY_COUNT,
   			     hw_jobs_limit, job_hang_limit,
   			     msecs_to_jiffies(hang_limit_ms), NULL,
   			     NULL, "v3d_bin", v3d->drm.dev);
@@ -397,6 +398,7 @@ v3d_sched_init(struct v3d_dev *v3d)
   
   	ret = drm_sched_init(&v3d->queue[V3D_RENDER].sched,
   			     &v3d_render_sched_ops,
+			     DRM_SCHED_PRIORITY_COUNT,
   			     hw_jobs_limit, job_hang_limit,
   			     msecs_to_jiffies(hang_limit_ms), NULL,
   			     NULL, "v3d_render", v3d->drm.dev);
@@ -405,6 +407,7 @@ v3d_sched_init(struct v3d_dev *v3d)
   
   	ret = drm_sched_init(&v3d->queue[V3D_TFU].sched,
   			     &v3d_tfu_sched_ops,
+			     DRM_SCHED_PRIORITY_COUNT,
   			     hw_jobs_limit, job_hang_limit,
   			     msecs_to_jiffies(hang_limit_ms), NULL,
   			     NULL, "v3d_tfu", v3d->drm.dev);
@@ -414,6 +417,7 @@ v3d_sched_init(struct v3d_dev *v3d)
   	if (v3d_has_csd(v3d)) {
   		ret = drm_sched_init(&v3d->queue[V3D_CSD].sched,
   				     &v3d_csd_sched_ops,
+				     DRM_SCHED_PRIORITY_COUNT,
   				     hw_jobs_limit, job_hang_limit,
   				     msecs_to_jiffies(hang_limit_ms), NULL,
   				     NULL, "v3d_csd", v3d->drm.dev);
@@ -422,6 +426,7 @@ v3d_sched_init(struct v3d_dev *v3d)
   
   		ret = drm_sched_init(&v3d->queue[V3D_CACHE_CLEAN].sched,
   				     &v3d_cache_clean_sched_ops,
+				     DRM_SCHED_PRIORITY_COUNT,
   				     hw_jobs_limit, job_hang_limit,
   				     msecs_to_jiffies(hang_limit_ms), NULL,
   				     NULL, "v3d_cache_clean", v3d->drm.dev);
diff --git a/include/drm/gpu_scheduler.h b/include/drm/gpu_scheduler.h
index ac65f0626cfc91..d2fb81e34174dc 100644
--- a/include/drm/gpu_scheduler.h
+++ b/include/drm/gpu_scheduler.h
@@ -471,7 +471,9 @@ struct drm_sched_backend_ops {
    * @hw_submission_limit: the max size of the hardware queue.
    * @timeout: the time after which a job is removed from the scheduler.
    * @name: name of the ring for which this scheduler is being used.
- * @sched_rq: priority wise array of run queues.
+ * @num_rqs: Number of run-queues. This is at most DRM_SCHED_PRIORITY_COUNT,
+ *           as there's usually one run-queue per priority, but could be less.
+ * @sched_rq: An allocated array of run-queues of size @num_rqs;
    * @wake_up_worker: the wait queue on which the scheduler sleeps until a job
    *                  is ready to be scheduled.
    * @job_scheduled: once @drm_sched_entity_do_release is called the scheduler
@@ -500,7 +502,8 @@ struct drm_gpu_scheduler {
   	uint32_t			hw_submission_limit;
   	long				timeout;
   	const char			*name;
-	struct drm_sched_rq		sched_rq[DRM_SCHED_PRIORITY_COUNT];
+	u32                             num_rqs;
+	struct drm_sched_rq             **sched_rq;
   	wait_queue_head_t		wake_up_worker;
   	wait_queue_head_t		job_scheduled;
   	atomic_t			hw_rq_count;
@@ -520,7 +523,7 @@ struct drm_gpu_scheduler {
   
   int drm_sched_init(struct drm_gpu_scheduler *sched,
   		   const struct drm_sched_backend_ops *ops,
-		   uint32_t hw_submission, unsigned hang_limit,
+		   u32 num_rqs, uint32_t hw_submission, unsigned int hang_limit,
   		   long timeout, struct workqueue_struct *timeout_wq,
   		   atomic_t *score, const char *name, struct device *dev);
   

base-commit: 05d3ef8bba77c1b5f98d941d8b2d4aeab8118ef1








