[PATCH 4/4] drm/amdgpu: reset fpriv vram_lost_counter

[Christian König]

Am 17.05.2017 um 10:01 schrieb Michel Dänzer:
> On 17/05/17 04:13 PM, zhoucm1 wrote:
>> On 2017年05月17日 14:57, Michel Dänzer wrote:
>>> On 17/05/17 01:28 PM, zhoucm1 wrote:
>>>> On 2017年05月17日 11:15, Michel Dänzer wrote:
>>>>> On 17/05/17 12:04 PM, zhoucm1 wrote:
>>>>>> On 2017年05月17日 09:18, Michel Dänzer wrote:
>>>>>>> On 16/05/17 06:25 PM, Chunming Zhou wrote:
>>>>>>>> Change-Id: I8eb6d7f558da05510e429d3bf1d48c8cec6c1977
>>>>>>>> Signed-off-by: Chunming Zhou <David1.Zhou at amd.com>
>>>>>>>>
>>>>>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>>>>>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>>>>>>>> index bca1fb5..f3e7525 100644
>>>>>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>>>>>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>>>>>>>> @@ -2547,6 +2547,9 @@ int amdgpu_vm_ioctl(struct drm_device *dev,
>>>>>>>> void *data, struct drm_file *filp)
>>>>>>>>          case AMDGPU_VM_OP_UNRESERVE_VMID:
>>>>>>>>              amdgpu_vm_free_reserved_vmid(adev, &fpriv->vm,
>>>>>>>> AMDGPU_GFXHUB);
>>>>>>>>              break;
>>>>>>>> +    case AMDGPU_VM_OP_RESET:
>>>>>>>> +        fpriv->vram_lost_counter =
>>>>>>>> atomic_read(&adev->vram_lost_counter);
>>>>>>>> +        break;
>>>>>>> How do you envision the UMDs using this? I can mostly think of them
>>>>>>> calling this ioctl when a context is created or destroyed. But that
>>>>>>> would also allow any other remaining contexts using the same DRM file
>>>>>>> descriptor to use all ioctls again. So, I think there needs to be a
>>>>>>> vram_lost_counter in struct amdgpu_ctx instead of in struct
>>>>>>> amdgpu_fpriv.
>>>>>> struct amdgpu_fpriv for vram_lost_counter is proper place, especially
>>>>>> for ioctl return value.
>>>>>> if you need to reset ctx one by one, we can mark all contexts of that
>>>>>> vm, and then reset by userspace.
>>>>> I'm not following. With vram_lost_counter in amdgpu_fpriv, if any
>>>>> context calls this ioctl, all other contexts using the same file
>>>>> descriptor will also be considered safe again, right?
>>>> Yes, but it really depends on userspace requirement, if you need to
>>>> reset ctx one by one, we can mark all contexts of that vm to guilty, and
>>>> then reset one context by userspace.
>>> Still not sure what you mean by that.
>>>
>>> E.g. what do you mean by "guilty"? I thought that refers to the context
>>> which caused a hang. But it seems like you're using it to refer to any
>>> context which hasn't reacted yet to VRAM contents being lost.
>> When vram is lost, we treat all contexts need to reset.
> Essentially, your patches only track VRAM contents being lost per file
> descriptor, not per context. I'm not sure (rather skeptical) that this
> is suitable for OpenGL UMDs, since state is usually tracked per context.
> Marek / Nicolai?

Oh, yeah that's a good point.

The problem with tracking it per context is that Vulkan also wants the 
ENODEV on the amdgpu_gem_va_ioct() and amdgpu_info_ioctl() which are 
context less.

But thinking more about this blocking those two doesn't make much sense. 
The VM content can be restored and why should be disallow reading GPU info?

Christian.