[PATCH v4 10/11] drm/amdgpu: only bound the eviction fence to userq bo

[Christian König]

On 01.07.25 15:21, Liang, Prike wrote:
> [Public]
> 
> Regards,
>       Prike
> 
>> -----Original Message-----
>> From: Koenig, Christian <Christian.Koenig at amd.com>
>> Sent: Wednesday, June 25, 2025 3:50 PM
>> To: Liang, Prike <Prike.Liang at amd.com>; amd-gfx at lists.freedesktop.org
>> Cc: Deucher, Alexander <Alexander.Deucher at amd.com>
>> Subject: Re: [PATCH v4 10/11] drm/amdgpu: only bound the eviction fence to userq
>> bo
>>
>> On 24.06.25 10:45, Prike Liang wrote:
>>> It doesn't need to attach the invalid eviction fence to non-userq's
>>> BOs.
>>
>> Clear NAK to this.
>>
>> BOs are often created before the userqs are created.
> Yes, but the eviction fence will only be available when the userq task is scheduled. Before requesting the userq-create IOCTL,
> the eviction fence is invalid and hasn't been created. In this case, do we need to attach an invalid eviction fence to the
> BO?

Yes, we do. Otherwise the whole approach is racy like hell.

Please don't change that in anyway.

Regards,
Christian.

> 
>> Regards,
>> Christian.
>>
>>>
>>> Signed-off-by: Prike Liang <Prike.Liang at amd.com>
>>> ---
>>>  drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c | 16 +++++++++-------
>>>  1 file changed, 9 insertions(+), 7 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
>>> index 2c68118fe9fd..50356aa23a99 100644
>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
>>> @@ -294,12 +294,14 @@ static int amdgpu_gem_object_open(struct
>> drm_gem_object *obj,
>>>     else
>>>             ++bo_va->ref_count;
>>>
>>> -   /* attach gfx eviction fence */
>>> -   r = amdgpu_eviction_fence_attach(&fpriv->evf_mgr, abo);
>>> -   if (r) {
>>> -           DRM_DEBUG_DRIVER("Failed to attach eviction fence to BO\n");
>>> -           amdgpu_bo_unreserve(abo);
>>> -           return r;
>>> +   /* attach gfx eviction fence when userq created*/
>>> +   if (vm->is_userq_context) {
>>> +           r = amdgpu_eviction_fence_attach(&fpriv->evf_mgr, abo);
>>> +           if (r) {
>>> +                   DRM_DEBUG_DRIVER("Failed to attach eviction fence to
>> BO\n");
>>> +                   amdgpu_bo_unreserve(abo);
>>> +                   return r;
>>> +           }
>>>     }
>>>
>>>     amdgpu_bo_unreserve(abo);
>>> @@ -365,7 +367,7 @@ static void amdgpu_gem_object_close(struct
>> drm_gem_object *obj,
>>>                     goto out_unlock;
>>>     }
>>>
>>> -   if (!amdgpu_vm_is_bo_always_valid(vm, bo))
>>> +   if (!amdgpu_vm_is_bo_always_valid(vm, bo) && vm->is_compute_context)
>>>             amdgpu_eviction_fence_detach(&fpriv->evf_mgr, bo);
>>>
>>>     bo_va = amdgpu_vm_bo_find(vm, bo);
>