[PATCH v2] drm/amdgpu: Skip the coredump collection on reset during driver reload

[Lazar, Lijo]

On 4/17/2024 1:14 PM, Khatri, Sunil wrote:
> 
> On 4/17/2024 1:06 PM, Khatri, Sunil wrote:
>> devcoredump is used to debug gpu hangs/resets. So in normal process
>> when there is a hang due to ring timeout or page fault we are doing a
>> hard reset as soft reset fail in those cases. How are we making sure
>> that the devcoredump is triggered in those cases and captured?
>>
>> Regards
>> Sunil Khatri
>>
>> On 4/17/2024 9:43 AM, Ahmad Rehman wrote:
>>> In passthrough environment, the driver triggers the mode-1 reset on
>>> reload. The reset causes the core dump collection which is delayed task
>>> and prevents driver from unloading until it is completed. Since we do
>>> not need to collect data on "reset on reload" case, we can skip core
>>> dump collection.
>>>
>>> v2: Use the same flag to avoid calling amdgpu_reset_reg_dumps as well.
>>>
>>> Signed-off-by: Ahmad Rehman <Ahmad.Rehman at amd.com>
>>> ---
>>>   drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 7 +++++--
>>>   drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c    | 1 +
>>>   drivers/gpu/drm/amd/amdgpu/amdgpu_reset.h  | 1 +
>>>   3 files changed, 7 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>>> index 1b2e177bc2d6..c718982cffa8 100644
>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>>> @@ -5357,7 +5357,9 @@ int amdgpu_do_asic_reset(struct list_head
>>> *device_list_handle,
>>>       /* Try reset handler method first */
>>>       tmp_adev = list_first_entry(device_list_handle, struct
>>> amdgpu_device,
>>>                       reset_list);
>>> -    amdgpu_reset_reg_dumps(tmp_adev);
>>> +
>>> +    if (!test_bit(AMDGPU_SKIP_COREDUMP, &reset_context->flags))
>>> +        amdgpu_reset_reg_dumps(tmp_adev);
>>>         reset_context->reset_device_list = device_list_handle;
>>>       r = amdgpu_reset_perform_reset(tmp_adev, reset_context);
>>> @@ -5430,7 +5432,8 @@ int amdgpu_do_asic_reset(struct list_head
>>> *device_list_handle,
>>>                     vram_lost = amdgpu_device_check_vram_lost(tmp_adev);
>>>   -                amdgpu_coredump(tmp_adev, vram_lost, reset_context);
>>> +                if (!test_bit(AMDGPU_SKIP_COREDUMP,
>>> &reset_context->flags))
>>> +                    amdgpu_coredump(tmp_adev, vram_lost,
>>> reset_context);
>>>                     if (vram_lost) {
>>>                       DRM_INFO("VRAM is lost due to GPU reset!\n");
>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
>>> index 6ea893ad9a36..c512f70b8272 100644
>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
>>> @@ -2481,6 +2481,7 @@ static void
>>> amdgpu_drv_delayed_reset_work_handler(struct work_struct *work)
>>>         /* Use a common context, just need to make sure full reset is
>>> done */
>>>       set_bit(AMDGPU_SKIP_HW_RESET, &reset_context.flags);
>>> +    set_bit(AMDGPU_SKIP_COREDUMP, &reset_context.flags);
> If this is used for guests only can we better have a flag like
> amdgpu_sriov_vf  for setting the skip coredump flag ??
> 

A reset is not always triggered just because of hang. There are other
cases like we want to do a reset after a suspend/resume cycle so that
the device starts from a clean state. Those are intentionally triggered
by driver. Also, there are case like RAS errors where we reset and that
also really doesn't need a core dump. In all such cases, this flag is
required, and this is one such case (this patch only addresses passthrough).

Thanks,
Lijo

> Regards
> Sunil khatri
> 
>>>       r = amdgpu_do_asic_reset(&device_list, &reset_context);
>>>         if (r) {
>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_reset.h
>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_reset.h
>>> index 66125d43cf21..b11d190ece53 100644
>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_reset.h
>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_reset.h
>>> @@ -32,6 +32,7 @@ enum AMDGPU_RESET_FLAGS {
>>>         AMDGPU_NEED_FULL_RESET = 0,
>>>       AMDGPU_SKIP_HW_RESET = 1,
>>> +    AMDGPU_SKIP_COREDUMP = 2,
>>>   };
>>>     struct amdgpu_reset_context {