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Andrey
On 2/16/21 12:07 PM, Andrey Grodzovsky wrote:
Problem: If scheduler is already stopped by the time sched_entity is released and entity's job_queue not empty I encountred a hang in drm_sched_entity_flush. This is because drm_sched_entity_is_idle never becomes false.
Fix: In drm_sched_fini detach all sched_entities from the scheduler's run queues. This will satisfy drm_sched_entity_is_idle. Also wakeup all those processes stuck in sched_entity flushing as the scheduler main thread which wakes them up is stopped by now.
Signed-off-by: Andrey Grodzovsky andrey.grodzovsky@amd.com
drivers/gpu/drm/scheduler/sched_main.c | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+)
diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c index 908b0b5..11abf5d 100644 --- a/drivers/gpu/drm/scheduler/sched_main.c +++ b/drivers/gpu/drm/scheduler/sched_main.c @@ -897,9 +897,40 @@ EXPORT_SYMBOL(drm_sched_init); */ void drm_sched_fini(struct drm_gpu_scheduler *sched) {
int i;
struct drm_sched_entity *s_entity; if (sched->thread) kthread_stop(sched->thread);
/* Detach all sched_entites from this scheduler once it's stopped */
for (i = DRM_SCHED_PRIORITY_COUNT - 1; i >= DRM_SCHED_PRIORITY_MIN; i--) {
struct drm_sched_rq *rq = &sched->sched_rq[i];if (!rq)continue;/* Loop this way because rq->lock is taken in drm_sched_rq_remove_entity */spin_lock(&rq->lock);while ((s_entity = list_first_entry_or_null(&rq->entities,struct drm_sched_entity,list))) {spin_unlock(&rq->lock);drm_sched_rq_remove_entity(rq, s_entity);/* Mark as stopped to reject adding to any new rq */spin_lock(&s_entity->rq_lock);s_entity->stopped = true;spin_unlock(&s_entity->rq_lock);spin_lock(&rq->lock);}spin_unlock(&rq->lock);}
/* Wakeup everyone stuck in drm_sched_entity_flush for this scheduler */
wake_up_all(&sched->job_scheduled);
/* Confirm no work left behind accessing device structures */ cancel_delayed_work_sync(&sched->work_tdr);