Re: [PATCH v2 2/2] drm/amdkfd: Stop user queues when process mm released

[Philip Yang <yangp@amd.com>]

On 2025-10-15 16:40, Chen, Xiaogang wrote:
>
>
> On 10/15/2025 3:11 PM, Philip Yang wrote:
>> In mmu notifier release callback, stop user queues to be safe because
>> the SVM memory is going to unmap from CPU.
>>
>> Suggested-by: Felix Kuehling<felix.kuehling@amd.com>
>> Signed-off-by: Philip Yang<Philip.Yang@amd.com>
>> ---
>>   drivers/gpu/drm/amd/amdkfd/kfd_process.c | 7 ++++++-
>>   1 file changed, 6 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_process.c b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
>> index 0341f570f3d1..e2a0ae0394b8 100644
>> --- a/drivers/gpu/drm/amd/amdkfd/kfd_process.c
>> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
>> @@ -1221,11 +1221,16 @@ static void kfd_process_free_notifier(struct mmu_notifier *mn)
>>   
>>   static void kfd_process_notifier_release_internal(struct kfd_process *p)
>>   {
>> -	int i;
>> +	int i, r;
>>   
>>   	cancel_delayed_work_sync(&p->eviction_work);
>>   	cancel_delayed_work_sync(&p->restore_work);
>>   
>> +	WARN(debug_evictions, "Evicting pid %d", p->lead_thread->pid);
>
> Use warning message or debug message? I saw this WARN are used several 
> places. If the queues from kfd process p are still running when come 
> here we need to stop them. It is not error. debug message is more 
> suitable I think.
>
The module parameter debug_evictions can be set to true, use WARN to 
dump call back trace to help understand why queue is evicted, by default 
debug_evictions is false.
>> +	r = kfd_process_evict_queues(p, KFD_QUEUE_EVICTION_TRIGGER_SVM);
>
> The evict reason KFD_QUEUE_EVICTION_TRIGGER_SVM is not good here as it 
> is general kfd process release. Maybe need another enum value.
>
Define new profiling event requires rocprofiler API change, 
KFD_QUEUE_EVICTION_TRIGGER_SVM seems the closest event from mmu notifier.

Regards,

Philip

> Regards
>
> Xiaogagn
>
>> +	if (r)
>> +		pr_debug("failed %d to quiesce KFD queues\n", r);
>> +
>>   	for (i = 0; i < p->n_pdds; i++) {
>>   		struct kfd_process_device *pdd = p->pdds[i];
>>