Re: [PATCH v8 3/3] drm/buddy: Add user for defragmentation

["Christian König" <ckoenig.leichtzumerken@gmail.com>]

Am 04.03.24 um 17:32 schrieb Arunpravin Paneer Selvam:
> Add amdgpu driver as user for the drm buddy
> defragmentation.
>
> Signed-off-by: Arunpravin Paneer Selvam <Arunpravin.PaneerSelvam@amd.com>
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c | 17 +++++++++++++++--
>   drivers/gpu/drm/drm_buddy.c                  |  1 +
>   2 files changed, 16 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
> index e494f5bf136a..cff8a526c622 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
> @@ -533,8 +533,21 @@ static int amdgpu_vram_mgr_new(struct ttm_resource_manager *man,
>   					   min_block_size,
>   					   &vres->blocks,
>   					   vres->flags);
> -		if (unlikely(r))
> -			goto error_free_blocks;
> +		if (unlikely(r)) {
> +			if (r == -ENOSPC) {
> +				drm_buddy_defrag(mm, min_block_size);
> +				r = drm_buddy_alloc_blocks(mm, fpfn,
> +							   lpfn,
> +							   size,
> +							   min_block_size,
> +							   &vres->blocks,
> +							   vres->flags);

That doesn't looks like something we should do.

We might fallback when contiguous memory is requested, but certainly not 
on normal allocation failure.

Regards,
Christian.

> +				if (unlikely(r))
> +					goto error_free_blocks;
> +			} else {
> +				goto error_free_blocks;
> +			}
> +		}
>   
>   		if (size > remaining_size)
>   			remaining_size = 0;
> diff --git a/drivers/gpu/drm/drm_buddy.c b/drivers/gpu/drm/drm_buddy.c
> index 40131ed9b0cd..19440f8caec0 100644
> --- a/drivers/gpu/drm/drm_buddy.c
> +++ b/drivers/gpu/drm/drm_buddy.c
> @@ -396,6 +396,7 @@ void drm_buddy_defrag(struct drm_buddy *mm,
>   		}
>   	}
>   }
> +EXPORT_SYMBOL(drm_buddy_defrag);
>   
>   /**
>    * drm_buddy_free_block - free a block