[PATCH 1/9] drm/amdgpu: generally allow over-commit during BO allocation

[Alex Deucher]

On Fri, Nov 25, 2022 at 5:21 AM Christian König
<ckoenig.leichtzumerken at gmail.com> wrote:
>
> We already fallback to a dummy BO with no backing store when we
> allocate GDS,GWS and OA resources and to GTT when we allocate VRAM.
>
> Drop all those workarounds and generalize this for GTT as well. This
> fixes ENOMEM issues with runaway applications which try to allocate/free
> GTT in a loop and are otherwise only limited by the CPU speed.
>
> The CS will wait for the cleanup of freed up BOs to satisfy the
> various domain specific limits and so effectively throttle those
> buggy applications down to a sane allocation behavior again.
>
> Signed-off-by: Christian König <christian.koenig at amd.com>

This looks like a good bug fix and unrelated to the rest of this series.
Reviewed-by: Alex Deucher <alexander.deucher at amd.com>

> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c    | 16 +++-------------
>  drivers/gpu/drm/amd/amdgpu/amdgpu_object.c |  6 +-----
>  2 files changed, 4 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
> index a0780a4e3e61..62e98f1ad770 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
> @@ -113,7 +113,7 @@ int amdgpu_gem_object_create(struct amdgpu_device *adev, unsigned long size,
>         bp.resv = resv;
>         bp.preferred_domain = initial_domain;
>         bp.flags = flags;
> -       bp.domain = initial_domain;
> +       bp.domain = initial_domain | AMDGPU_GEM_DOMAIN_CPU;
>         bp.bo_ptr_size = sizeof(struct amdgpu_bo);
>
>         r = amdgpu_bo_create_user(adev, &bp, &ubo);
> @@ -332,20 +332,10 @@ int amdgpu_gem_create_ioctl(struct drm_device *dev, void *data,
>         }
>
>         initial_domain = (u32)(0xffffffff & args->in.domains);
> -retry:
>         r = amdgpu_gem_object_create(adev, size, args->in.alignment,
> -                                    initial_domain,
> -                                    flags, ttm_bo_type_device, resv, &gobj);
> +                                    initial_domain, flags, ttm_bo_type_device,
> +                                    resv, &gobj);
>         if (r && r != -ERESTARTSYS) {
> -               if (flags & AMDGPU_GEM_CREATE_CPU_ACCESS_REQUIRED) {
> -                       flags &= ~AMDGPU_GEM_CREATE_CPU_ACCESS_REQUIRED;
> -                       goto retry;
> -               }
> -
> -               if (initial_domain == AMDGPU_GEM_DOMAIN_VRAM) {
> -                       initial_domain |= AMDGPU_GEM_DOMAIN_GTT;
> -                       goto retry;
> -               }
>                 DRM_DEBUG("Failed to allocate GEM object (%llu, %d, %llu, %d)\n",
>                                 size, initial_domain, args->in.alignment, r);
>         }
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
> index 974e85d8b6cc..919bbea2e3ac 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
> @@ -581,11 +581,7 @@ int amdgpu_bo_create(struct amdgpu_device *adev,
>                 bo->flags |= AMDGPU_GEM_CREATE_VRAM_WIPE_ON_RELEASE;
>
>         bo->tbo.bdev = &adev->mman.bdev;
> -       if (bp->domain & (AMDGPU_GEM_DOMAIN_GWS | AMDGPU_GEM_DOMAIN_OA |
> -                         AMDGPU_GEM_DOMAIN_GDS))
> -               amdgpu_bo_placement_from_domain(bo, AMDGPU_GEM_DOMAIN_CPU);
> -       else
> -               amdgpu_bo_placement_from_domain(bo, bp->domain);
> +       amdgpu_bo_placement_from_domain(bo, bp->domain);
>         if (bp->type == ttm_bo_type_kernel)
>                 bo->tbo.priority = 1;
>
> --
> 2.34.1
>