[PATCH] drm/scheduler: Add stopped flag to drm_sched_entity

[Zhou, David(ChunMing)]

-----Original Message-----
From: dri-devel <dri-devel-bounces at lists.freedesktop.org> On Behalf Of Andrey Grodzovsky
Sent: Friday, August 17, 2018 11:16 PM
To: dri-devel at lists.freedesktop.org
Cc: Koenig, Christian <Christian.Koenig at amd.com>; amd-gfx at lists.freedesktop.org
Subject: [PATCH] drm/scheduler: Add stopped flag to drm_sched_entity

The flag will prevent another thread from same process to reinsert the entity queue into scheduler's rq after it was already removed from there by another thread during drm_sched_entity_flush.

Signed-off-by: Andrey Grodzovsky <andrey.grodzovsky at amd.com>
---
 drivers/gpu/drm/scheduler/sched_entity.c | 10 +++++++++-
 include/drm/gpu_scheduler.h              |  2 ++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/scheduler/sched_entity.c b/drivers/gpu/drm/scheduler/sched_entity.c
index 1416edb..07cfe63 100644
--- a/drivers/gpu/drm/scheduler/sched_entity.c
+++ b/drivers/gpu/drm/scheduler/sched_entity.c
@@ -177,8 +177,12 @@ long drm_sched_entity_flush(struct drm_sched_entity *entity, long timeout)
 	/* For killed process disable any more IBs enqueue right now */
 	last_user = cmpxchg(&entity->last_user, current->group_leader, NULL);
 	if ((!last_user || last_user == current->group_leader) &&
-	    (current->flags & PF_EXITING) && (current->exit_code == SIGKILL))
+	    (current->flags & PF_EXITING) && (current->exit_code == SIGKILL)) {
+		spin_lock(&entity->rq_lock);
+		entity->stopped = true;
 		drm_sched_rq_remove_entity(entity->rq, entity);
+		spin_unlock(&entity->rq_lock);
+	}
 
 	return ret;
 }
@@ -504,6 +508,10 @@ void drm_sched_entity_push_job(struct drm_sched_job *sched_job,
 	if (first) {
 		/* Add the entity to the run queue */
 		spin_lock(&entity->rq_lock);
+		if (entity->stopped) {
+			spin_unlock(&entity->rq_lock);
+			return;
+		}
[DZ] the code changes so frequent recently and has this regression, my code synced last Friday still has below checking:
                spin_lock(&entity->rq_lock);
                if (!entity->rq) {
                        DRM_ERROR("Trying to push to a killed entity\n");
                        spin_unlock(&entity->rq_lock);
                        return;
                }
So you should add DRM_ERROR as well when hitting it.

With that fix, patch is Reviewed-by: Chunming Zhou <david1.zhou at amd.com>

Regards,
David Zhou
 		drm_sched_rq_add_entity(entity->rq, entity);
 		spin_unlock(&entity->rq_lock);
 		drm_sched_wakeup(entity->rq->sched);
diff --git a/include/drm/gpu_scheduler.h b/include/drm/gpu_scheduler.h index 919ae57..daec50f 100644
--- a/include/drm/gpu_scheduler.h
+++ b/include/drm/gpu_scheduler.h
@@ -70,6 +70,7 @@ enum drm_sched_priority {
  * @fini_status: contains the exit status in case the process was signalled.
  * @last_scheduled: points to the finished fence of the last scheduled job.
  * @last_user: last group leader pushing a job into the entity.
+ * @stopped: Marks the enity as removed from rq and destined for termination.
  *
  * Entities will emit jobs in order to their corresponding hardware
  * ring, and the scheduler will alternate between entities based on @@ -92,6 +93,7 @@ struct drm_sched_entity {
 	atomic_t			*guilty;
 	struct dma_fence                *last_scheduled;
 	struct task_struct		*last_user;
+	bool 				stopped;
 };
 
 /**
--
2.7.4

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