[PATCH v3 1/2] drm/sched: Avoid job cleanup if sched thread is parked.

[Steven Price]

On 25/11/2019 14:10, Andrey Grodzovsky wrote:
> When the sched thread is parked we assume ring_mirror_list is
> not accessed from here.

FWIW I don't think this is necessary. kthread_park() will wait until the
thread is parked, at which point the thread is stuck in kthread_parkme()
until unparked.

So all this does is avoid waiting for any cleanup jobs before parking -
which might be a reasonable goal in itself, but if so lets at least
document that.

Steve

> 
> Signed-off-by: Andrey Grodzovsky <andrey.grodzovsky at amd.com>
> Reviewed-by: Christian König <christian.koenig at amd.com>
> ---
>  drivers/gpu/drm/scheduler/sched_main.c | 10 +++++++---
>  1 file changed, 7 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
> index d4cc728..6774955 100644
> --- a/drivers/gpu/drm/scheduler/sched_main.c
> +++ b/drivers/gpu/drm/scheduler/sched_main.c
> @@ -635,9 +635,13 @@ drm_sched_get_cleanup_job(struct drm_gpu_scheduler *sched)
>  	struct drm_sched_job *job;
>  	unsigned long flags;
>  
> -	/* Don't destroy jobs while the timeout worker is running */
> -	if (sched->timeout != MAX_SCHEDULE_TIMEOUT &&
> -	    !cancel_delayed_work(&sched->work_tdr))
> +	/*
> +	* Don't destroy jobs while the timeout worker is running  OR thread
> +	* is being parked and hence assumed to not touch ring_mirror_list
> +	*/
> +	if ((sched->timeout != MAX_SCHEDULE_TIMEOUT &&
> +	     !cancel_delayed_work(&sched->work_tdr)) ||
> +	     __kthread_should_park(sched->thread))
>  		return NULL;
>  
>  	spin_lock_irqsave(&sched->job_list_lock, flags);
>