[PATCH v2 0/7] Fix multiple GPU resets in XGMI hive.

[Christian König]

Am 18.05.22 um 16:24 schrieb Andrey Grodzovsky:
>
>
> On 2022-05-18 02:07, Christian König wrote:
>> Am 17.05.22 um 21:20 schrieb Andrey Grodzovsky:
>>> Problem:
>>> During hive reset caused by command timing out on a ring
>>> extra resets are generated by triggered by KFD which is
>>> unable to accesses registers on the resetting ASIC.
>>>
>>> Fix: Rework GPU reset to actively stop any pending reset
>>> works while another in progress.
>>>
>>> v2: Switch from generic list as was in v1[1] to eplicit
>>> stopping of each reset request from each reset source
>>> per each request submitter.
>>
>> Looks mostly good to me.
>>
>> Apart from the naming nit pick on patch #1 the only thing I couldn't 
>> of hand figure out is why you are using a delayed work everywhere 
>> instead of a just a work item.
>>
>> That needs a bit further explanation what's happening here.
>>
>> Christian.
>
>
> Check APIs for cancelling work vs. delayed work -
>
> For work_struct the only public API is this - 
> https://elixir.bootlin.com/linux/latest/source/kernel/workqueue.c#L3214 
> - blocking cancel.
>
> For delayed_work we have both blocking and non blocking public APIs -
>
> https://elixir.bootlin.com/linux/latest/source/kernel/workqueue.c#L3295
>
> https://elixir.bootlin.com/linux/latest/source/kernel/workqueue.c#L3295
>
> I prefer not to go now into convincing core kernel people of exposing 
> another interface for our own sake - from my past experience API 
> changes in core code has slim chances and a lot of time spent on back 
> and forth arguments.
>
> "If the mountain will not come to Muhammad, then Muhammad must go to 
> the mountain" ;)*
> *
>

Ah, good point. The cancel_work() function was removed a few years ago:

commit 6417250d3f894e66a68ba1cd93676143f2376a6f
Author: Stephen Hemminger <stephen at networkplumber.org>
Date:   Tue Mar 6 19:34:42 2018 -0800

     workqueue: remove unused cancel_work()

     Found this by accident.
     There are no usages of bare cancel_work() in current kernel source.

     Signed-off-by: Stephen Hemminger <stephen at networkplumber.org>
     Signed-off-by: Tejun Heo <tj at kernel.org>


Maybe just revert that patch, export the function and use it. I think 
there is plenty of justification for this.

Thanks,
Christian.

> **
>
> Andrey
>
>>
>>>
>>> [1] - 
>>> https://lore.kernel.org/all/20220504161841.24669-1-andrey.grodzovsky@amd.com/
>>>
>>> Andrey Grodzovsky (7):
>>>    drm/amdgpu: Cache result of last reset at reset domain level.
>>>    drm/amdgpu: Switch to delayed work from work_struct.
>>>    drm/admgpu: Serialize RAS recovery work directly into reset domain
>>>      queue.
>>>    drm/amdgpu: Add delayed work for GPU reset from debugfs
>>>    drm/amdgpu: Add delayed work for GPU reset from kfd.
>>>    drm/amdgpu: Rename amdgpu_device_gpu_recover_imp back to
>>>      amdgpu_device_gpu_recover
>>>    drm/amdgpu: Stop any pending reset if another in progress.
>>>
>>>   drivers/gpu/drm/amd/amdgpu/amdgpu.h        |  4 +-
>>>   drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c | 15 +++++-
>>>   drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h |  1 +
>>>   drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 62 
>>> +++++++++++-----------
>>>   drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c  | 19 ++++++-
>>>   drivers/gpu/drm/amd/amdgpu/amdgpu_job.c    |  2 +-
>>>   drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c    | 10 ++--
>>>   drivers/gpu/drm/amd/amdgpu/amdgpu_ras.h    |  2 +-
>>>   drivers/gpu/drm/amd/amdgpu/amdgpu_reset.c  |  1 +
>>>   drivers/gpu/drm/amd/amdgpu/amdgpu_reset.h  |  5 +-
>>>   drivers/gpu/drm/amd/amdgpu/amdgpu_virt.h   |  2 +-
>>>   drivers/gpu/drm/amd/amdgpu/mxgpu_ai.c      |  6 +--
>>>   drivers/gpu/drm/amd/amdgpu/mxgpu_nv.c      |  6 +--
>>>   drivers/gpu/drm/amd/amdgpu/mxgpu_vi.c      |  6 +--
>>>   14 files changed, 87 insertions(+), 54 deletions(-)
>>>
>>
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