Re: [PATCH 36/53] drm/i915: Abstract the workload submission mechanism away

[Daniel Vetter <daniel@ffwll.ch>]

On Fri, Jun 13, 2014 at 04:37:54PM +0100, oscar.mateo@intel.com wrote:
> From: Oscar Mateo <oscar.mateo@intel.com>
> 
> As suggested by Daniel.
> 
> Signed-off-by: Oscar Mateo <oscar.mateo@intel.com>
> ---
>  drivers/gpu/drm/i915/i915_drv.h            | 26 ++++++++++++++++
>  drivers/gpu/drm/i915/i915_gem.c            | 48 +++++++++++++++++++-----------
>  drivers/gpu/drm/i915/i915_gem_execbuffer.c | 25 +++++++---------
>  3 files changed, 67 insertions(+), 32 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 3e9983c..89b6d5c 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -1554,6 +1554,23 @@ struct drm_i915_private {
>  	/* Old ums support infrastructure, same warning applies. */
>  	struct i915_ums_state ums;
>  
> +	/* Abstract the submission mechanism (legacy ringbuffer or execlists) away */
> +	struct {
> +		int (*do_execbuf) (struct drm_device *dev, struct drm_file *file,
> +				   struct intel_engine_cs *ring,
> +				   struct intel_context *ctx,
> +				   struct drm_i915_gem_execbuffer2 *args,
> +				   struct list_head *vmas,
> +				   struct drm_i915_gem_object *batch_obj,
> +				   u64 exec_start, u32 flags);
> +		int (*add_request) (struct intel_engine_cs *ring,
> +				    struct drm_file *file,
> +				    struct drm_i915_gem_object *obj,
> +				    u32 *out_seqno);

Hm, what do we need add_request for? With the clean split in command
submission I'd expect every function to know whether it'll submit to an
lrc (everything in intel_lrc.c) or whether it'll submit to a legacy ring
(existing code), so I don't see a need for an add_request vfunc.

Au contraire that looks a bit dangerous since code might get run with
execlist that assumes we have a legcy ring ...

A bit confused, but let's hope this clears up in further patches.
-Daniel

> +		int (*init_rings) (struct drm_device *dev);
> +		void (*cleanup_ring) (struct intel_engine_cs *ring);
> +	} gt;
> +
>  	/*
>  	 * NOTE: This is the dri1/ums dungeon, don't add stuff here. Your patch
>  	 * will be rejected. Instead look for a better place.
> @@ -2131,6 +2148,14 @@ void i915_gem_execbuffer_retire_commands(struct drm_device *dev,
>  					 struct drm_file *file,
>  					 struct intel_engine_cs *ring,
>  					 struct drm_i915_gem_object *obj);
> +int i915_gem_ringbuffer_submission(struct drm_device *dev,
> +				   struct drm_file *file,
> +				   struct intel_engine_cs *ring,
> +				   struct intel_context *ctx,
> +				   struct drm_i915_gem_execbuffer2 *args,
> +				   struct list_head *vmas,
> +				   struct drm_i915_gem_object *batch_obj,
> +				   u64 exec_start, u32 flags);
>  int i915_gem_execbuffer(struct drm_device *dev, void *data,
>  			struct drm_file *file_priv);
>  int i915_gem_execbuffer2(struct drm_device *dev, void *data,
> @@ -2281,6 +2306,7 @@ void i915_gem_reset(struct drm_device *dev);
>  bool i915_gem_clflush_object(struct drm_i915_gem_object *obj, bool force);
>  int __must_check i915_gem_object_finish_gpu(struct drm_i915_gem_object *obj);
>  int __must_check i915_gem_init(struct drm_device *dev);
> +int i915_gem_init_rings(struct drm_device *dev);
>  int __must_check i915_gem_init_hw(struct drm_device *dev);
>  int i915_gem_l3_remap(struct intel_engine_cs *ring, int slice);
>  void i915_gem_init_swizzling(struct drm_device *dev);
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index 69db71a..7c10540 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -2310,19 +2310,16 @@ i915_gem_get_seqno(struct drm_device *dev, u32 *seqno)
>  	return 0;
>  }
>  
> -int __i915_add_request(struct intel_engine_cs *ring,
> -		       struct drm_file *file,
> -		       struct drm_i915_gem_object *obj,
> -		       u32 *out_seqno)
> +static int i915_gem_add_request(struct intel_engine_cs *ring,
> +				struct drm_file *file,
> +				struct drm_i915_gem_object *obj,
> +				u32 *out_seqno)
>  {
>  	struct drm_i915_private *dev_priv = ring->dev->dev_private;
>  	struct drm_i915_gem_request *request;
>  	u32 request_ring_position, request_start;
>  	int ret;
>  
> -	if (intel_enable_execlists(ring->dev))
> -		return intel_logical_ring_add_request(ring, file, obj, out_seqno);
> -
>  	request_start = intel_ring_get_tail(ring->buffer);
>  	/*
>  	 * Emit any outstanding flushes - execbuf can fail to emit the flush
> @@ -2403,6 +2400,16 @@ int __i915_add_request(struct intel_engine_cs *ring,
>  	return 0;
>  }
>  
> +int __i915_add_request(struct intel_engine_cs *ring,
> +		       struct drm_file *file,
> +		       struct drm_i915_gem_object *obj,
> +		       u32 *out_seqno)
> +{
> +	struct drm_i915_private *dev_priv = ring->dev->dev_private;
> +
> +	return dev_priv->gt.add_request(ring, file, obj, out_seqno);
> +}
> +
>  static inline void
>  i915_gem_request_remove_from_client(struct drm_i915_gem_request *request)
>  {
> @@ -4627,7 +4634,7 @@ intel_enable_blt(struct drm_device *dev)
>  	return true;
>  }
>  
> -static int i915_gem_init_rings(struct drm_device *dev)
> +int i915_gem_init_rings(struct drm_device *dev)
>  {
>  	struct drm_i915_private *dev_priv = dev->dev_private;
>  	int ret;
> @@ -4710,10 +4717,7 @@ i915_gem_init_hw(struct drm_device *dev)
>  
>  	i915_gem_init_swizzling(dev);
>  
> -	if (intel_enable_execlists(dev))
> -		ret = intel_logical_rings_init(dev);
> -	else
> -		ret = i915_gem_init_rings(dev);
> +	ret = dev_priv->gt.init_rings(dev);
>  	if (ret)
>  		return ret;
>  
> @@ -4751,6 +4755,18 @@ int i915_gem_init(struct drm_device *dev)
>  			DRM_DEBUG_DRIVER("allow wake ack timed out\n");
>  	}
>  
> +	if (intel_enable_execlists(dev)) {
> +		dev_priv->gt.do_execbuf = intel_execlists_submission;
> +		dev_priv->gt.add_request = intel_logical_ring_add_request;
> +		dev_priv->gt.init_rings = intel_logical_rings_init;
> +		dev_priv->gt.cleanup_ring = intel_logical_ring_cleanup;
> +	} else {
> +		dev_priv->gt.do_execbuf = i915_gem_ringbuffer_submission;
> +		dev_priv->gt.add_request = i915_gem_add_request;
> +		dev_priv->gt.init_rings = i915_gem_init_rings;
> +		dev_priv->gt.cleanup_ring = intel_cleanup_ring_buffer;
> +	}
> +
>  	i915_gem_init_userptr(dev);
>  	i915_gem_init_global_gtt(dev);
>  
> @@ -4785,12 +4801,8 @@ i915_gem_cleanup_ringbuffer(struct drm_device *dev)
>  	struct intel_engine_cs *ring;
>  	int i;
>  
> -	for_each_ring(ring, dev_priv, i) {
> -		if (intel_enable_execlists(dev))
> -			intel_logical_ring_cleanup(ring);
> -		else
> -			intel_cleanup_ring_buffer(ring);
> -	}
> +	for_each_ring(ring, dev_priv, i)
> +		dev_priv->gt.cleanup_ring(ring);
>  }
>  
>  int
> diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> index 36c7f0c..f0dd31f 100644
> --- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> +++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> @@ -1005,14 +1005,15 @@ i915_reset_gen7_sol_offsets(struct drm_device *dev,
>  	return 0;
>  }
>  
> -static int
> -legacy_ringbuffer_submission(struct drm_device *dev, struct drm_file *file,
> -			     struct intel_engine_cs *ring,
> -			     struct intel_context *ctx,
> -			     struct drm_i915_gem_execbuffer2 *args,
> -			     struct list_head *vmas,
> -			     struct drm_i915_gem_object *batch_obj,
> -			     u64 exec_start, u32 flags)
> +int
> +i915_gem_ringbuffer_submission(struct drm_device *dev,
> +			       struct drm_file *file,
> +			       struct intel_engine_cs *ring,
> +			       struct intel_context *ctx,
> +			       struct drm_i915_gem_execbuffer2 *args,
> +			       struct list_head *vmas,
> +			       struct drm_i915_gem_object *batch_obj,
> +			       u64 exec_start, u32 flags)
>  {
>  	struct drm_clip_rect *cliprects = NULL;
>  	struct drm_i915_private *dev_priv = dev->dev_private;
> @@ -1379,12 +1380,8 @@ i915_gem_do_execbuffer(struct drm_device *dev, void *data,
>  	else
>  		exec_start += i915_gem_obj_offset(batch_obj, vm);
>  
> -	if (intel_enable_execlists(dev))
> -		ret = intel_execlists_submission(dev, file, ring, ctx,
> -				args, &eb->vmas, batch_obj, exec_start, flags);
> -	else
> -		ret = legacy_ringbuffer_submission(dev, file, ring, ctx,
> -				args, &eb->vmas, batch_obj, exec_start, flags);
> +	ret = dev_priv->gt.do_execbuf(dev, file, ring, ctx, args,
> +			&eb->vmas, batch_obj, exec_start, flags);
>  	if (ret)
>  		goto err;
>  
> -- 
> 1.9.0
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch