[Intel-gfx] [PATCH 14/37] drm/i915: Refactor export_fence() after i915_vma_move_to_active()

[Tvrtko Ursulin]

On 29/06/2018 08:53, Chris Wilson wrote:
> Currently all callers are responsible for adding the vma to the active
> timeline and then exporting its fence. Combine the two operations into
> i915_vma_move_to_active() to move all the extra handling from the
> callers to the single site.
> 
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> ---
>   drivers/gpu/drm/i915/i915_gem_execbuffer.c    | 47 +++++++++----------
>   drivers/gpu/drm/i915/selftests/huge_pages.c   |  4 --
>   .../drm/i915/selftests/i915_gem_coherency.c   |  4 --
>   .../gpu/drm/i915/selftests/i915_gem_context.c |  4 --
>   4 files changed, 21 insertions(+), 38 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> index c2dd9b4cdace..91f20445147f 100644
> --- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> +++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> @@ -1166,15 +1166,9 @@ static int __reloc_gpu_alloc(struct i915_execbuffer *eb,
>   
>   	GEM_BUG_ON(!reservation_object_test_signaled_rcu(batch->resv, true));
>   	i915_vma_move_to_active(batch, rq, 0);
> -	reservation_object_lock(batch->resv, NULL);
> -	reservation_object_add_excl_fence(batch->resv, &rq->fence);
> -	reservation_object_unlock(batch->resv);

Here now the exclusive fence is not added any more due flags being zero.

>   	i915_vma_unpin(batch);
>   
>   	i915_vma_move_to_active(vma, rq, EXEC_OBJECT_WRITE);
> -	reservation_object_lock(vma->resv, NULL);
> -	reservation_object_add_excl_fence(vma->resv, &rq->fence);
> -	reservation_object_unlock(vma->resv);
>   
>   	rq->batch = batch;
>   
> @@ -1771,25 +1765,6 @@ static int eb_relocate(struct i915_execbuffer *eb)
>   	return eb_relocate_slow(eb);
>   }
>   
> -static void eb_export_fence(struct i915_vma *vma,
> -			    struct i915_request *rq,
> -			    unsigned int flags)
> -{
> -	struct reservation_object *resv = vma->resv;
> -
> -	/*
> -	 * Ignore errors from failing to allocate the new fence, we can't
> -	 * handle an error right now. Worst case should be missed
> -	 * synchronisation leading to rendering corruption.
> -	 */
> -	reservation_object_lock(resv, NULL);
> -	if (flags & EXEC_OBJECT_WRITE)
> -		reservation_object_add_excl_fence(resv, &rq->fence);
> -	else if (reservation_object_reserve_shared(resv) == 0)
> -		reservation_object_add_shared_fence(resv, &rq->fence);
> -	reservation_object_unlock(resv);
> -}
> -
>   static int eb_move_to_gpu(struct i915_execbuffer *eb)
>   {
>   	const unsigned int count = eb->buffer_count;
> @@ -1844,7 +1819,6 @@ static int eb_move_to_gpu(struct i915_execbuffer *eb)
>   		struct i915_vma *vma = eb->vma[i];
>   
>   		i915_vma_move_to_active(vma, eb->request, flags);
> -		eb_export_fence(vma, eb->request, flags);
>   
>   		__eb_unreserve_vma(vma, flags);
>   		vma->exec_flags = NULL;
> @@ -1884,6 +1858,25 @@ static bool i915_gem_check_execbuffer(struct drm_i915_gem_execbuffer2 *exec)
>   	return true;
>   }
>   
> +static void export_fence(struct i915_vma *vma,
> +			 struct i915_request *rq,
> +			 unsigned int flags)
> +{
> +	struct reservation_object *resv = vma->resv;
> +
> +	/*
> +	 * Ignore errors from failing to allocate the new fence, we can't
> +	 * handle an error right now. Worst case should be missed
> +	 * synchronisation leading to rendering corruption.
> +	 */
> +	reservation_object_lock(resv, NULL);
> +	if (flags & EXEC_OBJECT_WRITE)
> +		reservation_object_add_excl_fence(resv, &rq->fence);
> +	else if (reservation_object_reserve_shared(resv) == 0)
> +		reservation_object_add_shared_fence(resv, &rq->fence);
> +	reservation_object_unlock(resv);
> +}
> +
>   void i915_vma_move_to_active(struct i915_vma *vma,
>   			     struct i915_request *rq,
>   			     unsigned int flags)
> @@ -1921,6 +1914,8 @@ void i915_vma_move_to_active(struct i915_vma *vma,
>   
>   	if (flags & EXEC_OBJECT_NEEDS_FENCE)
>   		i915_gem_active_set(&vma->last_fence, rq);
> +
> +	export_fence(vma, rq, flags);
>   }
>   
>   static int i915_reset_gen7_sol_offsets(struct i915_request *rq)
> diff --git a/drivers/gpu/drm/i915/selftests/huge_pages.c b/drivers/gpu/drm/i915/selftests/huge_pages.c
> index b5e87fcdcdae..358fc81f6c99 100644
> --- a/drivers/gpu/drm/i915/selftests/huge_pages.c
> +++ b/drivers/gpu/drm/i915/selftests/huge_pages.c
> @@ -998,10 +998,6 @@ static int gpu_write(struct i915_vma *vma,
>   
>   	i915_vma_move_to_active(vma, rq, EXEC_OBJECT_WRITE);
>   
> -	reservation_object_lock(vma->resv, NULL);
> -	reservation_object_add_excl_fence(vma->resv, &rq->fence);
> -	reservation_object_unlock(vma->resv);
> -
>   err_request:
>   	i915_request_add(rq);
>   
> diff --git a/drivers/gpu/drm/i915/selftests/i915_gem_coherency.c b/drivers/gpu/drm/i915/selftests/i915_gem_coherency.c
> index a4900091ae3d..11427aae0853 100644
> --- a/drivers/gpu/drm/i915/selftests/i915_gem_coherency.c
> +++ b/drivers/gpu/drm/i915/selftests/i915_gem_coherency.c
> @@ -225,10 +225,6 @@ static int gpu_set(struct drm_i915_gem_object *obj,
>   	i915_vma_move_to_active(vma, rq, EXEC_OBJECT_WRITE);
>   	i915_vma_unpin(vma);
>   
> -	reservation_object_lock(obj->resv, NULL);
> -	reservation_object_add_excl_fence(obj->resv, &rq->fence);
> -	reservation_object_unlock(obj->resv);
> -
>   	i915_request_add(rq);
>   
>   	return 0;
> diff --git a/drivers/gpu/drm/i915/selftests/i915_gem_context.c b/drivers/gpu/drm/i915/selftests/i915_gem_context.c
> index 3169b72180d0..a78f8bdb8222 100644
> --- a/drivers/gpu/drm/i915/selftests/i915_gem_context.c
> +++ b/drivers/gpu/drm/i915/selftests/i915_gem_context.c
> @@ -179,10 +179,6 @@ static int gpu_fill(struct drm_i915_gem_object *obj,
>   	i915_vma_move_to_active(vma, rq, 0);
>   	i915_vma_unpin(vma);
>   
> -	reservation_object_lock(obj->resv, NULL);
> -	reservation_object_add_excl_fence(obj->resv, &rq->fence);

Here as well this won't be added due zero flags.

> -	reservation_object_unlock(obj->resv);
> -
>   	i915_request_add(rq);
>   
>   	return 0;
> 

There is one i915_vma_move_to_active in render state and one in gvt 
which will now have some extra processing/allocations, do we care?

Regards,

Tvrtko