[RFC PATCH 2/2] drm/amdgpu: disable gpu load balancer for vcn jobs

[Nirmoy Das]

VCN HW  doesn't support dynamic load balance on multiple
instances for a context. This modifies the entity's sched_list
to a sched_list consist of only one drm scheduler.

Signed-off-by: Nirmoy Das <nirmoy.das at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c  |  1 +
 drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c | 25 +++++++++++++++++++++++++
 drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.h |  2 ++
 drivers/gpu/drm/amd/amdgpu/amdgpu_job.c |  1 +
 4 files changed, 29 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
index 8304d0c87899..00032093d8a9 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
@@ -1257,6 +1257,7 @@ static int amdgpu_cs_submit(struct amdgpu_cs_parser *p,
 	priority = job->base.s_priority;
 	drm_sched_entity_push_job(&job->base, entity);
 
+	amdgpu_ctx_limit_load_balance(entity);
 	amdgpu_vm_move_to_lru_tail(p->adev, &fpriv->vm);
 
 	ttm_eu_fence_buffer_objects(&p->ticket, &p->validated, p->fence);
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
index fa575bdc03c8..57b49188306d 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
@@ -139,6 +139,7 @@ static int amdgpu_ctx_init_entity(struct amdgpu_ctx *ctx, const u32 hw_ip, const
 	if (r)
 		goto error_free_entity;
 
+	entity->hw_ip = hw_ip;
 	ctx->entities[hw_ip][ring] = entity;
 	return 0;
 
@@ -559,6 +560,30 @@ void amdgpu_ctx_priority_override(struct amdgpu_ctx *ctx,
 	}
 }
 
+static void limit_vcn_load_balance(struct amdgpu_ctx_entity *centity)
+{
+	struct drm_gpu_scheduler **scheds = &centity->entity.rq->sched;
+
+	if (drm_sched_entity_num_jobs(&centity->entity) == 1)
+		drm_sched_entity_modify_sched(&centity->entity, scheds, 1);
+
+}
+
+void amdgpu_ctx_limit_load_balance(struct drm_sched_entity *entity)
+{
+	struct amdgpu_ctx_entity *centity = to_amdgpu_ctx_entity(entity);
+
+	if (!centity)
+		return;
+
+	switch (centity->hw_ip) {
+	case AMDGPU_HW_IP_VCN_DEC:
+	case AMDGPU_HW_IP_VCN_ENC:
+		limit_vcn_load_balance(centity);
+	}
+
+}
+
 int amdgpu_ctx_wait_prev_fence(struct amdgpu_ctx *ctx,
 			       struct drm_sched_entity *entity)
 {
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.h
index de490f183af2..d52d8d562d77 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.h
@@ -33,6 +33,7 @@ struct amdgpu_fpriv;
 
 struct amdgpu_ctx_entity {
 	uint64_t		sequence;
+	uint32_t		hw_ip;
 	struct drm_sched_entity	entity;
 	struct dma_fence	*fences[];
 };
@@ -90,5 +91,6 @@ void amdgpu_ctx_mgr_fini(struct amdgpu_ctx_mgr *mgr);
 
 void amdgpu_ctx_init_sched(struct amdgpu_device *adev);
 
+void amdgpu_ctx_limit_load_balance(struct drm_sched_entity *entity);
 
 #endif
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
index 4981e443a884..955d12bc89ae 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
@@ -154,6 +154,7 @@ int amdgpu_job_submit(struct amdgpu_job *job, struct drm_sched_entity *entity,
 	amdgpu_job_free_resources(job);
 	priority = job->base.s_priority;
 	drm_sched_entity_push_job(&job->base, entity);
+	amdgpu_ctx_limit_load_balance(entity);
 
 	return 0;
 }
-- 
2.25.0