Re: [PATCH 1/3] drm/amdgpu: add AMDGPU_GEM_CREATE_DISCARDABLE

["Marek Olšák" <maraeo@gmail.com>]

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A better flag name would be:
AMDGPU_GEM_CREATE_BEST_PLACEMENT_OR_DISCARD

Marek

On Tue, May 10, 2022 at 4:13 PM Marek Olšák <maraeo@gmail.com> wrote:

> Does this really guarantee VRAM placement? The code doesn't say anything
> about that.
>
> Marek
>
>
> On Fri, May 6, 2022 at 7:23 AM Christian König <
> ckoenig.leichtzumerken@gmail.com> wrote:
>
>> Add a AMDGPU_GEM_CREATE_DISCARDABLE flag to note that the content of a BO
>> doesn't needs to be preserved during eviction.
>>
>> KFD was already using a similar functionality for SVM BOs so replace the
>> internal flag with the new UAPI.
>>
>> Only compile tested!
>>
>> Signed-off-by: Christian König <christian.koenig@amd.com>
>> ---
>>  drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c    | 4 ++--
>>  drivers/gpu/drm/amd/amdgpu/amdgpu_object.c | 1 +
>>  drivers/gpu/drm/amd/amdgpu/amdgpu_object.h | 1 -
>>  drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c    | 2 +-
>>  drivers/gpu/drm/amd/amdkfd/kfd_svm.c       | 2 +-
>>  include/uapi/drm/amdgpu_drm.h              | 4 ++++
>>  6 files changed, 9 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
>> index 2e16484bf606..bf97d8f07f57 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
>> @@ -302,8 +302,8 @@ int amdgpu_gem_create_ioctl(struct drm_device *dev,
>> void *data,
>>                       AMDGPU_GEM_CREATE_VRAM_CLEARED |
>>                       AMDGPU_GEM_CREATE_VM_ALWAYS_VALID |
>>                       AMDGPU_GEM_CREATE_EXPLICIT_SYNC |
>> -                     AMDGPU_GEM_CREATE_ENCRYPTED))
>> -
>> +                     AMDGPU_GEM_CREATE_ENCRYPTED |
>> +                     AMDGPU_GEM_CREATE_DISCARDABLE))
>>                 return -EINVAL;
>>
>>         /* reject invalid gem domains */
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
>> index 8b7ee1142d9a..1944ef37a61e 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
>> @@ -567,6 +567,7 @@ int amdgpu_bo_create(struct amdgpu_device *adev,
>>                 bp->domain;
>>         bo->allowed_domains = bo->preferred_domains;
>>         if (bp->type != ttm_bo_type_kernel &&
>> +           !(bp->flags & AMDGPU_GEM_CREATE_DISCARDABLE) &&
>>             bo->allowed_domains == AMDGPU_GEM_DOMAIN_VRAM)
>>                 bo->allowed_domains |= AMDGPU_GEM_DOMAIN_GTT;
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.h
>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.h
>> index 4c9cbdc66995..147b79c10cbb 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.h
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.h
>> @@ -41,7 +41,6 @@
>>
>>  /* BO flag to indicate a KFD userptr BO */
>>  #define AMDGPU_AMDKFD_CREATE_USERPTR_BO        (1ULL << 63)
>> -#define AMDGPU_AMDKFD_CREATE_SVM_BO    (1ULL << 62)
>>
>>  #define to_amdgpu_bo_user(abo) container_of((abo), struct
>> amdgpu_bo_user, bo)
>>  #define to_amdgpu_bo_vm(abo) container_of((abo), struct amdgpu_bo_vm, bo)
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
>> index 41d6f604813d..ba3221a25e75 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
>> @@ -117,7 +117,7 @@ static void amdgpu_evict_flags(struct
>> ttm_buffer_object *bo,
>>         }
>>
>>         abo = ttm_to_amdgpu_bo(bo);
>> -       if (abo->flags & AMDGPU_AMDKFD_CREATE_SVM_BO) {
>> +       if (abo->flags & AMDGPU_GEM_CREATE_DISCARDABLE) {
>>                 placement->num_placement = 0;
>>                 placement->num_busy_placement = 0;
>>                 return;
>> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
>> b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
>> index 5ed8d9b549a4..835b5187f0b8 100644
>> --- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
>> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
>> @@ -531,7 +531,7 @@ svm_range_vram_node_new(struct amdgpu_device *adev,
>> struct svm_range *prange,
>>         bp.domain = AMDGPU_GEM_DOMAIN_VRAM;
>>         bp.flags = AMDGPU_GEM_CREATE_NO_CPU_ACCESS;
>>         bp.flags |= clear ? AMDGPU_GEM_CREATE_VRAM_CLEARED : 0;
>> -       bp.flags |= AMDGPU_AMDKFD_CREATE_SVM_BO;
>> +       bp.flags |= AMDGPU_GEM_CREATE_DISCARDABLE;
>>         bp.type = ttm_bo_type_device;
>>         bp.resv = NULL;
>>
>> diff --git a/include/uapi/drm/amdgpu_drm.h b/include/uapi/drm/amdgpu_drm.h
>> index 9a1d210d135d..57b9d8f0133a 100644
>> --- a/include/uapi/drm/amdgpu_drm.h
>> +++ b/include/uapi/drm/amdgpu_drm.h
>> @@ -140,6 +140,10 @@ extern "C" {
>>   * not require GTT memory accounting
>>   */
>>  #define AMDGPU_GEM_CREATE_PREEMPTIBLE          (1 << 11)
>> +/* Flag that BO can be discarded under memory pressure without keeping
>> the
>> + * content.
>> + */
>> +#define AMDGPU_GEM_CREATE_DISCARDABLE          (1 << 12)
>>
>>  struct drm_amdgpu_gem_create_in  {
>>         /** the requested memory size */
>> --
>> 2.25.1
>>
>>

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