[RFC v3 06/12] drm/amdgpu: Drop hive->in_reset

[Andrey Grodzovsky]

On 2022-02-08 01:33, Lazar, Lijo wrote:
>
>
> On 1/26/2022 4:07 AM, Andrey Grodzovsky wrote:
>> Since we serialize all resets no need to protect from concurrent
>> resets.
>>
>> Signed-off-by: Andrey Grodzovsky <andrey.grodzovsky at amd.com>
>> Reviewed-by: Christian König <christian.koenig at amd.com>
>> ---
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 19 +------------------
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_xgmi.c   |  1 -
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_xgmi.h   |  1 -
>>   3 files changed, 1 insertion(+), 20 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c 
>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>> index 258ec3c0b2af..107a393ebbfd 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>> @@ -5013,25 +5013,9 @@ int amdgpu_device_gpu_recover_imp(struct 
>> amdgpu_device *adev,
>>       dev_info(adev->dev, "GPU %s begin!\n",
>>           need_emergency_restart ? "jobs stop":"reset");
>>   -    /*
>> -     * Here we trylock to avoid chain of resets executing from
>> -     * either trigger by jobs on different adevs in XGMI hive or 
>> jobs on
>> -     * different schedulers for same device while this TO handler is 
>> running.
>> -     * We always reset all schedulers for device and all devices for 
>> XGMI
>> -     * hive so that should take care of them too.
>> -     */
>>       hive = amdgpu_get_xgmi_hive(adev);
>> -    if (hive) {
>> -        if (atomic_cmpxchg(&hive->in_reset, 0, 1) != 0) {
>> -            DRM_INFO("Bailing on TDR for s_job:%llx, hive: %llx as 
>> another already in progress",
>> -                job ? job->base.id : -1, hive->hive_id);
>> -            amdgpu_put_xgmi_hive(hive);
>> -            if (job && job->vm)
>> -                drm_sched_increase_karma(&job->base);
>> -            return 0;
>> -        }
>
> This function in general will reset all devices in a hive.
>
> In a situation like GPU0 in hive0 gets to this function first and GPU1 
> in hive0 also hangs shortly (before GPU0 recovery process starts 
> reseting other devices in hive), we don't want to execute work queued 
> as part of GPU1's recovery also.Both GPU0 and GPU1 recovery process 
> will try to reset all the devices in hive.
>
> In short - if a reset domain is already active, probably we don't need 
> to queue another work to the domain since all devices in the domain 
> are expected to get reset shortly.
>
> Thanks,
> Lijo


No worries for this - check this part in drm_sched_stop 
https://elixir.bootlin.com/linux/latest/source/drivers/gpu/drm/scheduler/sched_main.c#L452
this will be called for each scheduler participating in the reset domain 
(including schedulers of GPU) and will cancel any such pending resets that
we want to avoid executing.

Andrey


>
>> +    if (hive)
>>           mutex_lock(&hive->hive_lock);
>> -    }
>>         reset_context.method = AMD_RESET_METHOD_NONE;
>>       reset_context.reset_req_dev = adev;
>> @@ -5227,7 +5211,6 @@ int amdgpu_device_gpu_recover_imp(struct 
>> amdgpu_device *adev,
>>     skip_recovery:
>>       if (hive) {
>> -        atomic_set(&hive->in_reset, 0);
>>           mutex_unlock(&hive->hive_lock);
>>           amdgpu_put_xgmi_hive(hive);
>>       }
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_xgmi.c 
>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_xgmi.c
>> index a858e3457c5c..9ad742039ac9 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_xgmi.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_xgmi.c
>> @@ -404,7 +404,6 @@ struct amdgpu_hive_info 
>> *amdgpu_get_xgmi_hive(struct amdgpu_device *adev)
>>       INIT_LIST_HEAD(&hive->device_list);
>>       INIT_LIST_HEAD(&hive->node);
>>       mutex_init(&hive->hive_lock);
>> -    atomic_set(&hive->in_reset, 0);
>>       atomic_set(&hive->number_devices, 0);
>>       task_barrier_init(&hive->tb);
>>       hive->pstate = AMDGPU_XGMI_PSTATE_UNKNOWN;
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_xgmi.h 
>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_xgmi.h
>> index 6121aaa292cb..2f2ce53645a5 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_xgmi.h
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_xgmi.h
>> @@ -33,7 +33,6 @@ struct amdgpu_hive_info {
>>       struct list_head node;
>>       atomic_t number_devices;
>>       struct mutex hive_lock;
>> -    atomic_t in_reset;
>>       int hi_req_count;
>>       struct amdgpu_device *hi_req_gpu;
>>       struct task_barrier tb;
>>