On 26-03-2024 11:19, Matthew Brost wrote:

On Fri, Mar 22, 2024 at 08:45:58AM +0530, Himal Prasad Ghimiray wrote:

Instead of hardcoding the value 0, pass DRM_SCHED_PRIORITY_KERNEL as an
argument to drm_sched_entity_init.

v2
- Make changes in xe_execlist too. (Rodrigo)

Cc: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

Hold on, this is intentionally set to 0 not DRM_SCHED_PRIORITY_KERNEL.
In Xe we configure the scheduler with 1 priority level, thus the value
has to be zero. i.e. if enum DRM_SCHED_PRIORITY_KERNEL changes to
non-zero we are broken.

Better leave as is, or add new define like XE_SCHED_PRIORITY_DEFAULT == 0.

Matt

The function expects a parameter of type drm_sched_priority, and a static analyzer flagged our usage of hard-coded values.
Upon reviewing the implementation of drm_sched_entity_init, I discovered that the function is already safeguarded to handle
priority levels based on the scheduler's run_queues. Notably, altering DRM_SCHED_PRIORITY_KERNEL to a non-zero value could
potentially disrupt scheduler initialization itself (i = DRM_SCHED_PRIORITY_KERNEL; i < sched->num_rqs; i++) .

Therefore, utilizing it seemed like a safe approach.

However, defining

XE_SCHED_PRIORITY_DEFAULT
        == 0

and employing it doesn't seem logical.

Hence, if you perceive this change as risky or unsafe, lets drop it.

BR
Himal

---
 drivers/gpu/drm/xe/xe_execlist.c      | 2 +-
 drivers/gpu/drm/xe/xe_gpu_scheduler.h | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_execlist.c b/drivers/gpu/drm/xe/xe_execlist.c
index dece2785933c..57d3c11da591 100644
--- a/drivers/gpu/drm/xe/xe_execlist.c
+++ b/drivers/gpu/drm/xe/xe_execlist.c
@@ -341,7 +341,7 @@ static int execlist_exec_queue_init(struct xe_exec_queue *q)
 		goto err_free;
 
 	sched = &exl->sched;
-	err = drm_sched_entity_init(&exl->entity, 0, &sched, 1, NULL);
+	err = drm_sched_entity_init(&exl->entity, DRM_SCHED_PRIORITY_KERNEL, &sched, 1, NULL);
 	if (err)
 		goto err_sched;
 
diff --git a/drivers/gpu/drm/xe/xe_gpu_scheduler.h b/drivers/gpu/drm/xe/xe_gpu_scheduler.h
index 10c6bb9c9386..1f712f4fc76a 100644
--- a/drivers/gpu/drm/xe/xe_gpu_scheduler.h
+++ b/drivers/gpu/drm/xe/xe_gpu_scheduler.h
@@ -63,7 +63,7 @@ static inline int
 xe_sched_entity_init(struct xe_sched_entity *entity,
 		     struct xe_gpu_scheduler *sched)
 {
-	return drm_sched_entity_init(entity, 0,
+	return drm_sched_entity_init(entity, DRM_SCHED_PRIORITY_KERNEL,
 				     (struct drm_gpu_scheduler **)&sched,
 				     1, NULL);
 }
-- 
2.25.1