[PATCH] drm/amdgpu: simplify vram alloc logic since 2GB limitation removed

[Alex Deucher]

On Mon, Sep 23, 2024 at 4:28 AM Yifan Zhang <yifan1.zhang at amd.com> wrote:
>
> Make vram alloc loop simpler after 2GB limitation removed.

Can you provide more context?  What 2GB limitation are you referring to?

Alex

>
> Signed-off-by: Yifan Zhang <yifan1.zhang at amd.com>
> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c | 15 +++++----------
>  1 file changed, 5 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
> index 7d26a962f811..3d129fd61fa7 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
> @@ -455,7 +455,7 @@ static int amdgpu_vram_mgr_new(struct ttm_resource_manager *man,
>         struct amdgpu_bo *bo = ttm_to_amdgpu_bo(tbo);
>         u64 vis_usage = 0, max_bytes, min_block_size;
>         struct amdgpu_vram_mgr_resource *vres;
> -       u64 size, remaining_size, lpfn, fpfn;
> +       u64 size, lpfn, fpfn;
>         unsigned int adjust_dcc_size = 0;
>         struct drm_buddy *mm = &mgr->mm;
>         struct drm_buddy_block *block;
> @@ -516,25 +516,23 @@ static int amdgpu_vram_mgr_new(struct ttm_resource_manager *man,
>             adev->gmc.gmc_funcs->get_dcc_alignment)
>                 adjust_dcc_size = amdgpu_gmc_get_dcc_alignment(adev);
>
> -       remaining_size = (u64)vres->base.size;
> +       size = (u64)vres->base.size;
>         if (bo->flags & AMDGPU_GEM_CREATE_VRAM_CONTIGUOUS && adjust_dcc_size) {
>                 unsigned int dcc_size;
>
>                 dcc_size = roundup_pow_of_two(vres->base.size + adjust_dcc_size);
> -               remaining_size = (u64)dcc_size;
> +               size = (u64)dcc_size;
>
>                 vres->flags |= DRM_BUDDY_TRIM_DISABLE;
>         }
>
>         mutex_lock(&mgr->lock);
> -       while (remaining_size) {
> +       while (true) {
>                 if (tbo->page_alignment)
>                         min_block_size = (u64)tbo->page_alignment << PAGE_SHIFT;
>                 else
>                         min_block_size = mgr->default_page_size;
>
> -               size = remaining_size;
> -
>                 if (bo->flags & AMDGPU_GEM_CREATE_VRAM_CONTIGUOUS && adjust_dcc_size)
>                         min_block_size = size;
>                 else if ((size >= (u64)pages_per_block << PAGE_SHIFT) &&
> @@ -562,10 +560,7 @@ static int amdgpu_vram_mgr_new(struct ttm_resource_manager *man,
>                 if (unlikely(r))
>                         goto error_free_blocks;
>
> -               if (size > remaining_size)
> -                       remaining_size = 0;
> -               else
> -                       remaining_size -= size;
> +               break;
>         }
>         mutex_unlock(&mgr->lock);
>
> --
> 2.43.0
>