[PATCH 3/3] drm/amdgpu: set preferred_domain independent of fallback handling

[Christian König]

Am 11.04.2018 um 11:22 schrieb Christian König:
> Am 11.04.2018 um 04:38 schrieb zhoucm1:
>>
>>
>> On 2018年04月10日 21:42, Christian König wrote:
>>> When GEM needs to fallback to GTT for VRAM BOs we still want the
>>> preferred domain to be untouched so that the BO has a cance to move 
>>> back
>>> to VRAM in the future.
>>>
>>> Signed-off-by: Christian König <christian.koenig at amd.com>
>>> ---
>>>   drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c    | 14 +++++++++++---
>>>   drivers/gpu/drm/amd/amdgpu/amdgpu_object.c | 13 ++-----------
>>>   2 files changed, 13 insertions(+), 14 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c 
>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
>>> index 46b9ea4e6103..9dc0a190413c 100644
>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
>>> @@ -47,6 +47,7 @@ int amdgpu_gem_object_create(struct amdgpu_device 
>>> *adev, unsigned long size,
>>>                    struct reservation_object *resv,
>>>                    struct drm_gem_object **obj)
>>>   {
>>> +    uint32_t domain = initial_domain;
>>>       struct amdgpu_bo *bo;
>>>       int r;
>>>   @@ -57,7 +58,7 @@ int amdgpu_gem_object_create(struct 
>>> amdgpu_device *adev, unsigned long size,
>>>       }
>>>     retry:
>>> -    r = amdgpu_bo_create(adev, size, alignment, initial_domain,
>>> +    r = amdgpu_bo_create(adev, size, alignment, domain,
>>>                    flags, type, resv, &bo);
>>>       if (r) {
>>>           if (r != -ERESTARTSYS) {
>>> @@ -66,8 +67,8 @@ int amdgpu_gem_object_create(struct amdgpu_device 
>>> *adev, unsigned long size,
>>>                   goto retry;
>>>               }
>>>   -            if (initial_domain == AMDGPU_GEM_DOMAIN_VRAM) {
>>> -                initial_domain |= AMDGPU_GEM_DOMAIN_GTT;
>>> +            if (domain == AMDGPU_GEM_DOMAIN_VRAM) {
>>> +                domain |= AMDGPU_GEM_DOMAIN_GTT;
>>>                   goto retry;
>>>               }
>>>               DRM_DEBUG("Failed to allocate GEM object (%ld, %d, %u, 
>>> %d)\n",
>>> @@ -75,6 +76,13 @@ int amdgpu_gem_object_create(struct amdgpu_device 
>>> *adev, unsigned long size,
>>>           }
>>>           return r;
>>>       }
>>> +
>>> +    bo->preferred_domains = initial_domain;
>>> +    bo->allowed_domains = initial_domain;
>>> +    if (type != ttm_bo_type_kernel &&
>>> +        bo->allowed_domains == AMDGPU_GEM_DOMAIN_VRAM)
>>> +        bo->allowed_domains |= AMDGPU_GEM_DOMAIN_GTT;
>> It's an ugly change back after bo creation! Do you think it's better 
>> than previous?
>
> Well it's better than moving the fallback handling into the core 
> functions and then adding a flag to disable it again because we don't 
> want it in the core function.
>
>>
>> Alternative way, you can add one parameter to amdgpu_bo_create, 
>> directly pass preferred_domains and allowed_domains to amdgpu_bo_create.
>
> Then we would need three parameters, one where to create the BO now 
> and two for preferred/allowed domains.
>
> I think that in this case overwriting the placement from the initial 
> value looks cleaner to me.

Ping? Any more opinions on how to proceed?

I agree that neither solution is perfect, but updating the placement 
after we created the BO still sounds like the least painful to me.

Christian.

>
> Regards,
> Christian.
>
>>
>> Regards,
>> David Zhou
>>> +
>>>       *obj = &bo->gem_base;
>>>         return 0;
>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c 
>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
>>> index 6d08cde8443c..854d18d5cff4 100644
>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
>>> @@ -375,17 +375,8 @@ static int amdgpu_bo_do_create(struct 
>>> amdgpu_device *adev, unsigned long size,
>>>       drm_gem_private_object_init(adev->ddev, &bo->gem_base, size);
>>>       INIT_LIST_HEAD(&bo->shadow_list);
>>>       INIT_LIST_HEAD(&bo->va);
>>> -    bo->preferred_domains = domain & (AMDGPU_GEM_DOMAIN_VRAM |
>>> -                     AMDGPU_GEM_DOMAIN_GTT |
>>> -                     AMDGPU_GEM_DOMAIN_CPU |
>>> -                     AMDGPU_GEM_DOMAIN_GDS |
>>> -                     AMDGPU_GEM_DOMAIN_GWS |
>>> -                     AMDGPU_GEM_DOMAIN_OA);
>>> -    bo->allowed_domains = bo->preferred_domains;
>>> -    if (type != ttm_bo_type_kernel &&
>>> -        bo->allowed_domains == AMDGPU_GEM_DOMAIN_VRAM)
>>> -        bo->allowed_domains |= AMDGPU_GEM_DOMAIN_GTT;
>>> -
>>> +    bo->preferred_domains = domain;
>>> +    bo->allowed_domains = domain;
>>>       bo->flags = flags;
>>>     #ifdef CONFIG_X86_32
>>
>