[PATCH 1/5] drm/amdgpu: handle IH ring1 overflow
Christian König
ckoenig.leichtzumerken at gmail.com
Wed Nov 10 14:54:14 UTC 2021
Am 10.11.21 um 15:44 schrieb philip yang:
>
> On 2021-11-10 9:31 a.m., Christian König wrote:
>
>> Am 10.11.21 um 14:59 schrieb philip yang:
>>>
>>> On 2021-11-10 5:15 a.m., Christian König wrote:
>>>
>>>> [SNIP]
>>>
>>> It is hard to understand, this debug log can explain more details,
>>> with this debug message patch
>>>
>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ih.c
>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_ih.c
>>> index ed6f8d24280b..8859f2bb11b1 100644
>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ih.c
>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ih.c
>>> @@ -234,10 +235,12 @@ int amdgpu_ih_process(struct amdgpu_device
>>> *adev, struct amdgpu_ih_ring *ih)
>>> return IRQ_NONE;
>>>
>>> wptr = amdgpu_ih_get_wptr(adev, ih);
>>> + if (ih == &adev->irq.ih1)
>>> + pr_debug("entering rptr 0x%x, wptr 0x%x\n",
>>> ih->rptr, wptr);
>>>
>>> restart_ih:
>>> + if (ih == &adev->irq.ih1)
>>> + pr_debug("starting rptr 0x%x, wptr 0x%x\n",
>>> ih->rptr, wptr);
>>>
>>> /* Order reading of wptr vs. reading of IH ring data */
>>> rmb();
>>> @@ -245,8 +248,12 @@ int amdgpu_ih_process(struct amdgpu_device
>>> *adev, struct amdgpu_ih_ring *ih)
>>> while (ih->rptr != wptr && --count) {
>>> amdgpu_irq_dispatch(adev, ih);
>>> ih->rptr &= ih->ptr_mask;
>>> + if (ih == &adev->irq.ih1) {
>>> + pr_debug("rptr 0x%x, old wptr 0x%x, new wptr
>>> 0x%x\n",
>>> + ih->rptr, wptr,
>>> + amdgpu_ih_get_wptr(adev, ih));
>>> + }
>>> }
>>>
>>> amdgpu_ih_set_rptr(adev, ih);
>>> @@ -257,6 +264,8 @@ int amdgpu_ih_process(struct amdgpu_device
>>> *adev, struct amdgpu_ih_ring *ih)
>>> if (wptr != ih->rptr)
>>> goto restart_ih;
>>>
>>> + if (ih == &adev->irq.ih1)
>>> + pr_debug("exiting rptr 0x%x, wptr 0x%x\n", ih->rptr,
>>> wptr);
>>> return IRQ_HANDLED;
>>> }
>>>
>>> This is log, timing 48.807028, ring1 drain is done, rptr == wptr,
>>> ring1 is empty, but the loop continues, to handle outdated retry fault.
>>>
>>
>> As far as I can see that is perfectly correct and expected behavior.
>>
>> See the ring buffer overflowed and because of that the loop
>> continues, but that is correct because an overflow means that the
>> ring was filled with new entries.
>>
>> So we are processing new entries here, not stale ones.
>
> wptr is 0x840, 0x860.....0xd20 is not new entries, it is stale retry
> fault, the loop will continue handle stale fault to 0xd20 and then
> exit loop, it is because wptr pass rptr after timing 48.806122.
>
Yeah, but 0x840..0xd20 still contain perfectly valid IVs which you drop
on the ground with your approach. That's not something we can do.
What can happen is that the ring buffer overflows and we process the
same IV twice, but that is also perfectly expected behavior when an
overflow happens.
Regards,
Christian.
> Regards.
>
> Philip
>
>>
>> Regards,
>> Christian.
>>
>>> [ 48.802231] amdgpu_ih_process:243: amdgpu: starting rptr 0x520,
>>> wptr 0xd20
>>> [ 48.802235] amdgpu_ih_process:254: amdgpu: rptr 0x540, old wptr
>>> 0xd20, new wptr 0xd20
>>> [ 48.802256] amdgpu_ih_process:254: amdgpu: rptr 0x560, old wptr
>>> 0xd20, new wptr 0xd20
>>> [ 48.802260] amdgpu_ih_process:254: amdgpu: rptr 0x580, old wptr
>>> 0xd20, new wptr 0xd20
>>> [ 48.802281] amdgpu_ih_process:254: amdgpu: rptr 0x5a0, old wptr
>>> 0xd20, new wptr 0xd20
>>> [ 48.802314] amdgpu_ih_process:254: amdgpu: rptr 0x5c0, old wptr
>>> 0xd20, new wptr 0xce0
>>> [ 48.802335] amdgpu_ih_process:254: amdgpu: rptr 0x5e0, old wptr
>>> 0xd20, new wptr 0xce0
>>> [ 48.802356] amdgpu_ih_process:254: amdgpu: rptr 0x600, old wptr
>>> 0xd20, new wptr 0xce0
>>> [ 48.802376] amdgpu_ih_process:254: amdgpu: rptr 0x620, old wptr
>>> 0xd20, new wptr 0xce0
>>> [ 48.802396] amdgpu_ih_process:254: amdgpu: rptr 0x640, old wptr
>>> 0xd20, new wptr 0xce0
>>> [ 48.802401] amdgpu_ih_process:254: amdgpu: rptr 0x660, old wptr
>>> 0xd20, new wptr 0xce0
>>> [ 48.802421] amdgpu_ih_process:254: amdgpu: rptr 0x680, old wptr
>>> 0xd20, new wptr 0xce0
>>> [ 48.802442] amdgpu_ih_process:254: amdgpu: rptr 0x6a0, old wptr
>>> 0xd20, new wptr 0xce0
>>> [ 48.802463] amdgpu_ih_process:254: amdgpu: rptr 0x6c0, old wptr
>>> 0xd20, new wptr 0xce0
>>> [ 48.802483] amdgpu_ih_process:254: amdgpu: rptr 0x6e0, old wptr
>>> 0xd20, new wptr 0xce0
>>> [ 48.802503] amdgpu_ih_process:254: amdgpu: rptr 0x700, old wptr
>>> 0xd20, new wptr 0xce0
>>> [ 48.802523] amdgpu_ih_process:254: amdgpu: rptr 0x720, old wptr
>>> 0xd20, new wptr 0xce0
>>> [ 48.802544] amdgpu_ih_process:254: amdgpu: rptr 0x740, old wptr
>>> 0xd20, new wptr 0xce0
>>> [ 48.802565] amdgpu_ih_process:254: amdgpu: rptr 0x760, old wptr
>>> 0xd20, new wptr 0xce0
>>> [ 48.802569] amdgpu_ih_process:254: amdgpu: rptr 0x780, old wptr
>>> 0xd20, new wptr 0xce0
>>> [ 48.804392] amdgpu_ih_process:254: amdgpu: rptr 0x7a0, old wptr
>>> 0xd20, new wptr 0xf00
>>> [ 48.806122] amdgpu_ih_process:254: amdgpu: rptr 0x7c0, old wptr
>>> 0xd20, new wptr 0x840
>>> [ 48.806155] amdgpu_ih_process:254: amdgpu: rptr 0x7e0, old wptr
>>> 0xd20, new wptr 0x840
>>> [ 48.806965] amdgpu_ih_process:254: amdgpu: rptr 0x800, old wptr
>>> 0xd20, new wptr 0x840
>>> [ 48.806995] amdgpu_ih_process:254: amdgpu: rptr 0x820, old wptr
>>> 0xd20, new wptr 0x840
>>> [ 48.807028] amdgpu_ih_process:254: amdgpu: rptr 0x840, old wptr
>>> 0xd20, new wptr 0x840
>>> [ 48.807063] amdgpu_ih_process:254: amdgpu: rptr 0x860, old wptr
>>> 0xd20, new wptr 0x840
>>> [ 48.808421] amdgpu_ih_process:254: amdgpu: rptr 0x880, old wptr
>>> 0xd20, new wptr 0x840
>>>
>>> Cause this gpu vm fault dump because address is unmapped from cpu.
>>>
>>> [ 48.807071] svm_range_restore_pages:2617: amdgpu: restoring svms
>>> 0x00000000733bf007 fault address 0x7f8a6991f
>>>
>>> [ 48.807170] svm_range_restore_pages:2631: amdgpu: failed to find
>>> prange svms 0x00000000733bf007 address [0x7f8a6991f]
>>> [ 48.807179] svm_range_get_range_boundaries:2348: amdgpu: VMA does
>>> not exist in address [0x7f8a6991f]
>>> [ 48.807185] svm_range_restore_pages:2635: amdgpu: failed to
>>> create unregistered range svms 0x00000000733bf007 address [0x7f8a6991f]
>>>
>>> [ 48.807929] amdgpu 0000:25:00.0: amdgpu: [mmhub0] retry page
>>> fault (src_id:0 ring:0 vmid:8 pasid:32770, for process kfdtest pid
>>> 3969 thread kfdtest pid 3969)
>>> [ 48.808219] amdgpu 0000:25:00.0: amdgpu: in page starting at
>>> address 0x00007f8a6991f000 from IH client 0x12 (VMC)
>>> [ 48.808230] amdgpu 0000:25:00.0: amdgpu:
>>> VM_L2_PROTECTION_FAULT_STATUS:0x00800031
>>>
>>>> We could of course parameterize that so that we check the wptr
>>>> after each IV on IH1, but please not hard coded like this.
>>>>
>>>> Regards,
>>>> Christian.
>>>>
>>>>> }
>>>>> amdgpu_ih_set_rptr(adev, ih);
>>>>
>>
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