Re: [PATCH 13/43] drm/i915: Abstract the legacy workload submission mechanism away

Daniel Vetter
2014-08-11T14:36:41Z

On Thu, Jul 24, 2014 at 05:04:21PM +0100, Thomas Daniel wrote:
> From: Oscar Mateo <oscar.mateo@intel.com>
>
> As suggested by Daniel Vetter. The idea, in subsequent patches, is to
> provide an alternative to these vfuncs for the Execlists submission
> mechanism.
>
> v2: Splitted into two and reordered to illustrate our intentions, instead
> of showing it off. Also, remove the add_request vfunc and added the
> stop_ring one.
>
> Signed-off-by: Oscar Mateo <oscar.mateo@intel.com>
> ---
> drivers/gpu/drm/i915/i915_drv.h | 24 ++++++++++++++++++++++++
> drivers/gpu/drm/i915/i915_gem.c | 15 +++++++++++----
> drivers/gpu/drm/i915/i915_gem_execbuffer.c | 20 ++++++++++----------
> 3 files changed, 45 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index ff2c373..1caed52 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -1617,6 +1617,21 @@ 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 (*init_rings) (struct drm_device *dev);
> + void (*cleanup_ring) (struct intel_engine_cs *ring);
> + void (*stop_ring) (struct intel_engine_cs *ring);

My rule of thumb is that with just one caller it's probably better to not
have a vtable - just makes it harder to follow the code flow.

Usually (with non-borked code design at least) init/teardown functions
have only one caller, so there's a good chance I'll ask you to remove them
again.

> + bool (*is_ring_initialized) (struct intel_engine_cs *ring);

This one is unused and I didn't really like the taste of it. So I killed
it.
-Daniel

> + } gt;
> +
> /*
> * NOTE: This is the dri1/ums dungeon, don't add stuff here. Your patch
> * will be rejected. Instead look for a better place.
> @@ -2224,6 +2239,14 @@ int i915_gem_set_domain_ioctl(struct drm_device *dev, void *data,
> struct drm_file *file_priv);
> int i915_gem_sw_finish_ioctl(struct drm_device *dev, void *data,
> struct drm_file *file_priv);
> +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,
> @@ -2376,6 +2399,7 @@ 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 d8bf4fa..6544286 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -4518,7 +4518,7 @@ i915_gem_stop_ringbuffers(struct drm_device *dev)
> int i;
>
> for_each_ring(ring, dev_priv, i)
> - intel_stop_ring_buffer(ring);
> + dev_priv->gt.stop_ring(ring);
> }
>
> int
> @@ -4635,7 +4635,7 @@ 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;
> @@ -4718,7 +4718,7 @@ i915_gem_init_hw(struct drm_device *dev)
>
> i915_gem_init_swizzling(dev);
>
> - ret = i915_gem_init_rings(dev);
> + ret = dev_priv->gt.init_rings(dev);
> if (ret)
> return ret;
>
> @@ -4759,6 +4759,13 @@ int i915_gem_init(struct drm_device *dev)
> DRM_DEBUG_DRIVER("allow wake ack timed out\n");
> }
>
> + if (!i915.enable_execlists) {
> + dev_priv->gt.do_execbuf = i915_gem_ringbuffer_submission;
> + dev_priv->gt.init_rings = i915_gem_init_rings;
> + dev_priv->gt.cleanup_ring = intel_cleanup_ring_buffer;
> + dev_priv->gt.stop_ring = intel_stop_ring_buffer;
> + }
> +
> i915_gem_init_userptr(dev);
> i915_gem_init_global_gtt(dev);
>
> @@ -4794,7 +4801,7 @@ i915_gem_cleanup_ringbuffer(struct drm_device *dev)
> int i;
>
> for_each_ring(ring, dev_priv, i)
> - intel_cleanup_ring_buffer(ring);
> + 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 4e9b387..8c63d79 100644
> --- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> +++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> @@ -1034,14 +1034,14 @@ 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;
> @@ -1408,8 +1408,8 @@ i915_gem_do_execbuffer(struct drm_device *dev, void *data,
> else
> exec_start += i915_gem_obj_offset(batch_obj, vm);
>
> - 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;
>
> --
> 1.7.9.5
>
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> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch