[PATCH] drm/sched: fix the bug of time out calculation(v3)

[Christian König]

Am 26.08.21 um 13:55 schrieb Liu, Monk:
> [AMD Official Use Only]
>
>>> I'm not sure if the work_tdr is initialized when a maximum timeout is specified. Please double check.
> Ok, will do
>
>>> BTW: Can we please drop the "tdr" naming from the scheduler? That is just a timeout functionality and not related to recovery in any way.
> We even do not start hardware recovery in a lot of cases now (when wave kill is successfully).
>
> Umm, sounds reasonable, I can rename it to "to" with another patch

Maybe more like job_timeout or timeout_work or something into that 
direction.

Christian.

>
> Thanks
>
> ------------------------------------------
> Monk Liu | Cloud-GPU Core team
> ------------------------------------------
>
> -----Original Message-----
> From: Christian König <ckoenig.leichtzumerken at gmail.com>
> Sent: Thursday, August 26, 2021 6:09 PM
> To: Liu, Monk <Monk.Liu at amd.com>; amd-gfx at lists.freedesktop.org
> Cc: dri-devel at lists.freedesktop.org
> Subject: Re: [PATCH] drm/sched: fix the bug of time out calculation(v3)
>
> Am 26.08.21 um 06:55 schrieb Monk Liu:
>> issue:
>> in cleanup_job the cancle_delayed_work will cancel a TO timer even the
>> its corresponding job is still running.
> Yeah, that makes a lot more sense.
>
>> fix:
>> do not cancel the timer in cleanup_job, instead do the cancelling only
>> when the heading job is signaled, and if there is a "next" job we
>> start_timeout again.
>>
>> v2:
>> further cleanup the logic, and do the TDR timer cancelling if the
>> signaled job is the last one in its scheduler.
>>
>> v3:
>> change the issue description
>> remove the cancel_delayed_work in the begining of the cleanup_job
>> recover the implement of drm_sched_job_begin.
>>
>> TODO:
>> 1)introduce pause/resume scheduler in job_timeout to serial the
>> handling of scheduler and job_timeout.
>> 2)drop the bad job's del and insert in scheduler due to above
>> serialization (no race issue anymore with the serialization)
>>
>> Signed-off-by: Monk Liu <Monk.Liu at amd.com>
>> ---
>>    drivers/gpu/drm/scheduler/sched_main.c | 25 ++++++++++---------------
>>    1 file changed, 10 insertions(+), 15 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/scheduler/sched_main.c
>> b/drivers/gpu/drm/scheduler/sched_main.c
>> index a2a9536..ecf8140 100644
>> --- a/drivers/gpu/drm/scheduler/sched_main.c
>> +++ b/drivers/gpu/drm/scheduler/sched_main.c
>> @@ -676,13 +676,7 @@ drm_sched_get_cleanup_job(struct drm_gpu_scheduler *sched)
>>    {
>>    	struct drm_sched_job *job, *next;
>>    
>> -	/*
>> -	 * Don't destroy jobs while the timeout worker is running  OR thread
>> -	 * is being parked and hence assumed to not touch pending_list
>> -	 */
>> -	if ((sched->timeout != MAX_SCHEDULE_TIMEOUT &&
>> -	    !cancel_delayed_work(&sched->work_tdr)) ||
>> -	    kthread_should_park())
>> +	if (kthread_should_park())
>>    		return NULL;
>>    
>>    	spin_lock(&sched->job_list_lock);
>> @@ -693,17 +687,21 @@ drm_sched_get_cleanup_job(struct drm_gpu_scheduler *sched)
>>    	if (job && dma_fence_is_signaled(&job->s_fence->finished)) {
>>    		/* remove job from pending_list */
>>    		list_del_init(&job->list);
>> +
>> +		/* cancel this job's TO timer */
>> +		cancel_delayed_work(&sched->work_tdr);
> I'm not sure if the work_tdr is initialized when a maximum timeout is specified. Please double check.
>
> BTW: Can we please drop the "tdr" naming from the scheduler? That is just a timeout functionality and not related to recovery in any way.
>
> We even do not start hardware recovery in a lot of cases now (when wave kill is successfully).
>
> Regards,
> Christian.
>
>>    		/* make the scheduled timestamp more accurate */
>>    		next = list_first_entry_or_null(&sched->pending_list,
>>    						typeof(*next), list);
>> -		if (next)
>> +
>> +		if (next) {
>>    			next->s_fence->scheduled.timestamp =
>>    				job->s_fence->finished.timestamp;
>> -
>> +			/* start TO timer for next job */
>> +			drm_sched_start_timeout(sched);
>> +		}
>>    	} else {
>>    		job = NULL;
>> -		/* queue timeout for next job */
>> -		drm_sched_start_timeout(sched);
>>    	}
>>    
>>    	spin_unlock(&sched->job_list_lock);
>> @@ -791,11 +789,8 @@ static int drm_sched_main(void *param)
>>    					  (entity = drm_sched_select_entity(sched))) ||
>>    					 kthread_should_stop());
>>    
>> -		if (cleanup_job) {
>> +		if (cleanup_job)
>>    			sched->ops->free_job(cleanup_job);
>> -			/* queue timeout for next job */
>> -			drm_sched_start_timeout(sched);
>> -		}
>>    
>>    		if (!entity)
>>    			continue;