Re: [PATCH 3/3] drm/amdgpu: Move to gtt before cpu accesses dma buf.

[Christian König <ckoenig.leichtzumerken@xxxxxxxxx>]

Am 15.12.2017 um 17:33 schrieb Samuel Li:
> To improve cpu read performance. This is implemented for APUs currently.
>
> v2: Adapt to change https://lists.freedesktop.org/archives/amd-gfx/2017-October/015174.html
> v3: Adapt to change "forward begin_cpu_access callback to drivers"
>
> Change-Id: I7a583e23a9ee706e0edd2a46f4e4186a609368e3
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu.h       |  1 +
>   drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c   |  1 +
>   drivers/gpu/drm/amd/amdgpu/amdgpu_prime.c | 26 ++++++++++++++++++++++++++
>   3 files changed, 28 insertions(+)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> index f8657c3..4204d87 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> @@ -420,6 +420,7 @@ struct dma_buf *amdgpu_gem_prime_export(struct drm_device *dev,
>   int amdgpu_gem_prime_pin(struct drm_gem_object *obj);
>   void amdgpu_gem_prime_unpin(struct drm_gem_object *obj);
>   struct reservation_object *amdgpu_gem_prime_res_obj(struct drm_gem_object *);
> +int amdgpu_gem_prime_begin_cpu_access(struct drm_gem_object *obj, enum dma_data_direction direction);
>   void *amdgpu_gem_prime_vmap(struct drm_gem_object *obj);
>   void amdgpu_gem_prime_vunmap(struct drm_gem_object *obj, void *vaddr);
>   int amdgpu_gem_prime_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma);
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> index 31383e0..87d05b5 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> @@ -874,6 +874,7 @@ static struct drm_driver kms_driver = {
>   	.gem_prime_res_obj = amdgpu_gem_prime_res_obj,
>   	.gem_prime_get_sg_table = amdgpu_gem_prime_get_sg_table,
>   	.gem_prime_import_sg_table = amdgpu_gem_prime_import_sg_table,
> +	.gem_prime_begin_cpu_access = amdgpu_gem_prime_begin_cpu_access,
>   	.gem_prime_vmap = amdgpu_gem_prime_vmap,
>   	.gem_prime_vunmap = amdgpu_gem_prime_vunmap,
>   	.gem_prime_mmap = amdgpu_gem_prime_mmap,
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_prime.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_prime.c
> index ae9c106..1f5063e 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_prime.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_prime.c
> @@ -26,6 +26,7 @@
>   #include <drm/drmP.h>
>   
>   #include "amdgpu.h"
> +#include "amdgpu_display.h"
>   #include <drm/amdgpu_drm.h>
>   #include <linux/dma-buf.h>
>   
> @@ -164,6 +165,30 @@ struct reservation_object *amdgpu_gem_prime_res_obj(struct drm_gem_object *obj)
>   	return bo->tbo.resv;
>   }
>   
> +int amdgpu_gem_prime_begin_cpu_access(struct drm_gem_object *obj, enum dma_data_direction direction)
> +{
> +	struct amdgpu_bo *bo = gem_to_amdgpu_bo(obj);
> +	struct amdgpu_device *adev = amdgpu_ttm_adev(bo->tbo.bdev);
> +	struct ttm_operation_ctx ctx = { true, false };
> +	u32 domain = amdgpu_framebuffer_domains(adev);
> +	long ret = 0;
> +	bool reads = (direction == DMA_BIDIRECTIONAL || direction == DMA_FROM_DEVICE);

Reverse tree order please and ret should be an int in this case.

> +
> +	if (!reads || !(domain & AMDGPU_GEM_DOMAIN_GTT) || bo->pin_count)
> +		return 0;

bo->pin_count is protected by the BO being reserved.

> +
> +	/* move to gtt */
> +	ret = amdgpu_bo_reserve(bo, false);
> +	if (unlikely(ret != 0))
> +		return ret;
> +
> +	amdgpu_ttm_placement_from_domain(bo, AMDGPU_GEM_DOMAIN_GTT);
> +	ret = ttm_bo_validate(&bo->tbo, &bo->placement, &ctx);
> +
> +	amdgpu_bo_unreserve(bo);
> +	return ret;
> +}
> +
>   struct dma_buf *amdgpu_gem_prime_export(struct drm_device *dev,
>   					struct drm_gem_object *gobj,
>   					int flags)
> @@ -178,5 +203,6 @@ struct dma_buf *amdgpu_gem_prime_export(struct drm_device *dev,
>   	buf = drm_gem_prime_export(dev, gobj, flags);
>   	if (!IS_ERR(buf))
>   		buf->file->f_mapping = dev->anon_inode->i_mapping;
> +

Unrelated whitespace change.

Christian.

>   	return buf;
>   }

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