drm/amdgpu: allocate entities on demand

Currently we pre-allocate entities and fences for all the HW IPs on
context creation and some of which are might never be used.

This patch tries to resolve entity/fences wastage by creating entity
only when needed.

v2: allocate memory for entity and fences together

Signed-off-by: Nirmoy Das <[e-mail]>
Reviewed-by: Christian König <[e-mail]>
Signed-off-by: Alex Deucher <[e-mail]>

drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c

···
 	[AMDGPU_HW_IP_VCN_JPEG]	=	1,
 };
 
-static int amdgpu_ctx_total_num_entities(void)
-{
-	unsigned i, num_entities = 0;
-
-	for (i = 0; i < AMDGPU_HW_IP_NUM; ++i)
-		num_entities += amdgpu_ctx_num_entities[i];
-
-	return num_entities;
-}
-
 static int amdgpu_ctx_priority_permit(struct drm_file *filp,
 				      enum drm_sched_priority priority)
 {
+	if (priority < 0 || priority >= DRM_SCHED_PRIORITY_MAX)
+		return -EINVAL;
+
 	/* NORMAL and below are accessible by everyone */
 	if (priority <= DRM_SCHED_PRIORITY_NORMAL)
 		return 0;
···
 	return -EACCES;
 }
 
-static int amdgpu_ctx_init(struct amdgpu_device *adev,
-			   enum drm_sched_priority priority,
-			   struct drm_file *filp,
-			   struct amdgpu_ctx *ctx)
+static int amdgpu_ctx_init_entity(struct amdgpu_ctx *ctx, const u32 hw_ip, const u32 ring)
 {
-	unsigned num_entities = amdgpu_ctx_total_num_entities();
-	unsigned i, j;
+	struct amdgpu_device *adev = ctx->adev;
+	struct amdgpu_ctx_entity *entity;
+	struct drm_gpu_scheduler **scheds = NULL, *sched = NULL;
+	unsigned num_scheds = 0;
+	enum drm_sched_priority priority;
 	int r;
 
-	if (priority < 0 || priority >= DRM_SCHED_PRIORITY_MAX)
-		return -EINVAL;
+	entity = kcalloc(1, offsetof(typeof(*entity), fences[amdgpu_sched_jobs]),
+			 GFP_KERNEL);
+	if (!entity)
+		return  -ENOMEM;
 
-	r = amdgpu_ctx_priority_permit(filp, priority);
-	if (r)
-		return r;
-
-	memset(ctx, 0, sizeof(*ctx));
-	ctx->adev = adev;
-
-
-	ctx->entities[0] = kcalloc(num_entities,
-				   sizeof(struct amdgpu_ctx_entity),
-				   GFP_KERNEL);
-	if (!ctx->entities[0])
-		return -ENOMEM;
-
-
-	for (i = 0; i < num_entities; ++i) {
-		struct amdgpu_ctx_entity *entity = &ctx->entities[0][i];
-
-		entity->sequence = 1;
-		entity->fences = kcalloc(amdgpu_sched_jobs,
-					 sizeof(struct dma_fence*), GFP_KERNEL);
-		if (!entity->fences) {
-			r = -ENOMEM;
-			goto error_cleanup_memory;
-		}
-	}
-	for (i = 1; i < AMDGPU_HW_IP_NUM; ++i)
-		ctx->entities[i] = ctx->entities[i - 1] +
-			amdgpu_ctx_num_entities[i - 1];
-
-	kref_init(&ctx->refcount);
-	spin_lock_init(&ctx->ring_lock);
-	mutex_init(&ctx->lock);
-
-	ctx->reset_counter = atomic_read(&adev->gpu_reset_counter);
-	ctx->reset_counter_query = ctx->reset_counter;
-	ctx->vram_lost_counter = atomic_read(&adev->vram_lost_counter);
-	ctx->init_priority = priority;
-	ctx->override_priority = DRM_SCHED_PRIORITY_UNSET;
-
-	for (i = 0; i < AMDGPU_HW_IP_NUM; ++i) {
-		struct drm_gpu_scheduler **scheds;
-		struct drm_gpu_scheduler *sched;
-		unsigned num_scheds = 0;
-
-		switch (i) {
+	entity->sequence = 1;
+	priority = (ctx->override_priority == DRM_SCHED_PRIORITY_UNSET) ?
+				ctx->init_priority : ctx->override_priority;
+	switch (hw_ip) {
 		case AMDGPU_HW_IP_GFX:
 			sched = &adev->gfx.gfx_ring[0].sched;
 			scheds = &sched;
···
 			scheds = adev->jpeg.jpeg_sched;
 			num_scheds =  adev->jpeg.num_jpeg_sched;
 			break;
-		}
-
-		for (j = 0; j < amdgpu_ctx_num_entities[i]; ++j)
-			r = drm_sched_entity_init(&ctx->entities[i][j].entity,
-						  priority, scheds,
-						  num_scheds, &ctx->guilty);
-		if (r)
-			goto error_cleanup_entities;
 	}
+
+	r = drm_sched_entity_init(&entity->entity, priority, scheds, num_scheds,
+				  &ctx->guilty);
+	if (r)
+		goto error_free_entity;
+
+	ctx->entities[hw_ip][ring] = entity;
+	return 0;
+
+error_free_entity:
+	kfree(entity);
+
+	return r;
+}
+
+static int amdgpu_ctx_init(struct amdgpu_device *adev,
+			   enum drm_sched_priority priority,
+			   struct drm_file *filp,
+			   struct amdgpu_ctx *ctx)
+{
+	int r;
+
+	r = amdgpu_ctx_priority_permit(filp, priority);
+	if (r)
+		return r;
+
+	memset(ctx, 0, sizeof(*ctx));
+
+	ctx->adev = adev;
+
+	kref_init(&ctx->refcount);
+	spin_lock_init(&ctx->ring_lock);
+	mutex_init(&ctx->lock);
+
+	ctx->reset_counter = atomic_read(&adev->gpu_reset_counter);
+	ctx->reset_counter_query = ctx->reset_counter;
+	ctx->vram_lost_counter = atomic_read(&adev->vram_lost_counter);
+	ctx->init_priority = priority;
+	ctx->override_priority = DRM_SCHED_PRIORITY_UNSET;
 
 	return 0;
 
-error_cleanup_entities:
-	for (i = 0; i < num_entities; ++i)
-		drm_sched_entity_destroy(&ctx->entities[0][i].entity);
+}
 
-error_cleanup_memory:
-	for (i = 0; i < num_entities; ++i) {
-		struct amdgpu_ctx_entity *entity = &ctx->entities[0][i];
+static void amdgpu_ctx_fini_entity(struct amdgpu_ctx_entity *entity)
+{
 
-		kfree(entity->fences);
-		entity->fences = NULL;
-	}
+	int i;
 
-	kfree(ctx->entities[0]);
-	ctx->entities[0] = NULL;
-	return r;
+	if (!entity)
+		return;
+
+	for (i = 0; i < amdgpu_sched_jobs; ++i)
+		dma_fence_put(entity->fences[i]);
+
+	kfree(entity);
 }
 
 static void amdgpu_ctx_fini(struct kref *ref)
 {
 	struct amdgpu_ctx *ctx = container_of(ref, struct amdgpu_ctx, refcount);
-	unsigned num_entities = amdgpu_ctx_total_num_entities();
 	struct amdgpu_device *adev = ctx->adev;
 	unsigned i, j;
 
 	if (!adev)
 		return;
 
-	for (i = 0; i < num_entities; ++i) {
-		struct amdgpu_ctx_entity *entity = &ctx->entities[0][i];
-
-		for (j = 0; j < amdgpu_sched_jobs; ++j)
-			dma_fence_put(entity->fences[j]);
-
-		kfree(entity->fences);
+	for (i = 0; i < AMDGPU_HW_IP_NUM; ++i) {
+		for (j = 0; j < AMDGPU_MAX_ENTITY_NUM; ++j) {
+			amdgpu_ctx_fini_entity(ctx->entities[i][j]);
+			ctx->entities[i][j] = NULL;
+		}
 	}
 
-	kfree(ctx->entities[0]);
 	mutex_destroy(&ctx->lock);
-
 	kfree(ctx);
 }
 
 int amdgpu_ctx_get_entity(struct amdgpu_ctx *ctx, u32 hw_ip, u32 instance,
 			  u32 ring, struct drm_sched_entity **entity)
 {
+	int r;
+
 	if (hw_ip >= AMDGPU_HW_IP_NUM) {
 		DRM_ERROR("unknown HW IP type: %d\n", hw_ip);
 		return -EINVAL;
···
 		return -EINVAL;
 	}
 
-	*entity = &ctx->entities[hw_ip][ring].entity;
+	if (ctx->entities[hw_ip][ring] == NULL) {
+		r = amdgpu_ctx_init_entity(ctx, hw_ip, ring);
+		if (r)
+			return r;
+	}
+
+	*entity = &ctx->entities[hw_ip][ring]->entity;
 	return 0;
 }
 
···
 static void amdgpu_ctx_do_release(struct kref *ref)
 {
 	struct amdgpu_ctx *ctx;
-	unsigned num_entities;
-	u32 i;
+	u32 i, j;
 
 	ctx = container_of(ref, struct amdgpu_ctx, refcount);
+	for (i = 0; i < AMDGPU_HW_IP_NUM; ++i) {
+		for (j = 0; j < amdgpu_ctx_num_entities[i]; ++j) {
+			if (!ctx->entities[i][j])
+				continue;
 
-	num_entities = amdgpu_ctx_total_num_entities();
-	for (i = 0; i < num_entities; i++)
-		drm_sched_entity_destroy(&ctx->entities[0][i].entity);
+			drm_sched_entity_destroy(&ctx->entities[i][j]->entity);
+		}
+	}
 
 	amdgpu_ctx_fini(ref);
 }
···
 void amdgpu_ctx_priority_override(struct amdgpu_ctx *ctx,
 				  enum drm_sched_priority priority)
 {
-	unsigned num_entities = amdgpu_ctx_total_num_entities();
 	enum drm_sched_priority ctx_prio;
-	unsigned i;
+	unsigned i, j;
 
 	ctx->override_priority = priority;
 
 	ctx_prio = (ctx->override_priority == DRM_SCHED_PRIORITY_UNSET) ?
 			ctx->init_priority : ctx->override_priority;
+	for (i = 0; i < AMDGPU_HW_IP_NUM; ++i) {
+		for (j = 0; j < amdgpu_ctx_num_entities[i]; ++j) {
+			struct drm_sched_entity *entity;
 
-	for (i = 0; i < num_entities; i++) {
-		struct drm_sched_entity *entity = &ctx->entities[0][i].entity;
+			if (!ctx->entities[i][j])
+				continue;
 
-		drm_sched_entity_set_priority(entity, ctx_prio);
+			entity = &ctx->entities[i][j]->entity;
+			drm_sched_entity_set_priority(entity, ctx_prio);
+		}
 	}
 }
 
···
 
 long amdgpu_ctx_mgr_entity_flush(struct amdgpu_ctx_mgr *mgr, long timeout)
 {
-	unsigned num_entities = amdgpu_ctx_total_num_entities();
 	struct amdgpu_ctx *ctx;
 	struct idr *idp;
-	uint32_t id, i;
+	uint32_t id, i, j;
 
 	idp = &mgr->ctx_handles;
 
 	mutex_lock(&mgr->lock);
 	idr_for_each_entry(idp, ctx, id) {
-		for (i = 0; i < num_entities; i++) {
-			struct drm_sched_entity *entity;
+		for (i = 0; i < AMDGPU_HW_IP_NUM; ++i) {
+			for (j = 0; j < amdgpu_ctx_num_entities[i]; ++j) {
+				struct drm_sched_entity *entity;
 
-			entity = &ctx->entities[0][i].entity;
-			timeout = drm_sched_entity_flush(entity, timeout);
+				if (!ctx->entities[i][j])
+					continue;
+
+				entity = &ctx->entities[i][j]->entity;
+				timeout = drm_sched_entity_flush(entity, timeout);
+			}
 		}
 	}
 	mutex_unlock(&mgr->lock);
···
 
 void amdgpu_ctx_mgr_entity_fini(struct amdgpu_ctx_mgr *mgr)
 {
-	unsigned num_entities = amdgpu_ctx_total_num_entities();
 	struct amdgpu_ctx *ctx;
 	struct idr *idp;
-	uint32_t id, i;
+	uint32_t id, i, j;
 
 	idp = &mgr->ctx_handles;
 
···
 			continue;
 		}
 
-		for (i = 0; i < num_entities; i++)
-			drm_sched_entity_fini(&ctx->entities[0][i].entity);
+		for (i = 0; i < AMDGPU_HW_IP_NUM; ++i) {
+			for (j = 0; j < amdgpu_ctx_num_entities[i]; ++j) {
+				struct drm_sched_entity *entity;
+
+				if (!ctx->entities[i][j])
+					continue;
+
+				entity = &ctx->entities[i][j]->entity;
+				drm_sched_entity_fini(entity);
+			}
+		}
 	}
 }
 

drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.h

···
 struct drm_file;
 struct amdgpu_fpriv;
 
+#define AMDGPU_MAX_ENTITY_NUM 4
+
 struct amdgpu_ctx_entity {
 	uint64_t		sequence;
-	struct dma_fence	**fences;
 	struct drm_sched_entity	entity;
+	struct dma_fence	*fences[];
 };
 
 struct amdgpu_ctx {
···
 	unsigned			reset_counter_query;
 	uint32_t			vram_lost_counter;
 	spinlock_t			ring_lock;
-	struct amdgpu_ctx_entity	*entities[AMDGPU_HW_IP_NUM];
+	struct amdgpu_ctx_entity	*entities[AMDGPU_HW_IP_NUM][AMDGPU_MAX_ENTITY_NUM];
 	bool				preamble_presented;
 	enum drm_sched_priority		init_priority;
 	enum drm_sched_priority		override_priority;