On 06/02/2025 16:54, Danilo Krummrich wrote:
On Thu, Feb 06, 2025 at 04:40:29PM +0000, Tvrtko Ursulin wrote:
Idea is to add helpers for peeking and popping jobs from entities with
the goal of decoupling the hidden assumption in the code that queue_node
is the first element in struct drm_sched_job.
That assumption usually comes in the form of:
while ((job = to_drm_sched_job(spsc_queue_pop(&entity->job_queue))))
Which breaks if the queue_node is re-positioned due to_drm_sched_job
being implemented with a container_of.
This also allows us to remove duplicate definitions of to_drm_sched_job.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxxx>
Cc: Christian König <christian.koenig@xxxxxxx>
Cc: Danilo Krummrich <dakr@xxxxxxxxxx>
Cc: Matthew Brost <matthew.brost@xxxxxxxxx>
Cc: Philipp Stanner <phasta@xxxxxxxxxx>
---
drivers/gpu/drm/scheduler/sched_entity.c | 11 +++---
drivers/gpu/drm/scheduler/sched_internal.h | 43 ++++++++++++++++++++++
drivers/gpu/drm/scheduler/sched_main.c | 7 ++--
3 files changed, 51 insertions(+), 10 deletions(-)
create mode 100644 drivers/gpu/drm/scheduler/sched_internal.h
diff --git a/drivers/gpu/drm/scheduler/sched_internal.h b/drivers/gpu/drm/scheduler/sched_internal.h
new file mode 100644
index 000000000000..565c83e32371
--- /dev/null
+++ b/drivers/gpu/drm/scheduler/sched_internal.h
@@ -0,0 +1,43 @@
+
+
+/**
+ * __drm_sched_entity_queue_pop - Low level helper for popping queued jobs
Why the '__' prefix?
True, it is a remnant from v1 when I had it in gpu_scheduler.h because
then double underscores were supposed to signal this is "special"
(internal) API. After adding sched_internal.h it makes no more sense. I
will drop them.
Speaking of sched_internal.h, as a follow up we could also move a bunch
of other prototypes from gpu_scheduler.h in there.
Could also use this to replace spsc_queue_pop() in drm_sched_entity_pop_job().
We could but as that caller does not want/need the job returned maybe
okay not to. Open to change if you insist.
+ *
+ * @entity: scheduler entity
+ *
+ * Low level helper for popping queued jobs.
+ *
+ * Returns the job dequeued or NULL.
+ */
+static inline struct drm_sched_job *
+__drm_sched_entity_queue_pop(struct drm_sched_entity *entity)
+{
+ struct spsc_node *node;
+
+ node = spsc_queue_pop(&entity->job_queue);
+ if (!node)
+ return NULL;
+
+ return container_of(node, struct drm_sched_job, queue_node);
+}
+
+/**
+ * __drm_sched_entity_queue_peek - Low level helper for peeking at the job queue
Same here.
Could also use this for drm_sched_entity_is_ready().
Again we could but that one does not want a job but just a does a "queue
not empty" check. Could replace also with spsc_queue_count() to make
that clearer.
Regards,
Tvrtko
+ *
+ * @entity: scheduler entity
+ *
+ * Low level helper for peeking at the job queue
+ *
+ * Returns the job at the head of the queue or NULL.
+ */
+static inline struct drm_sched_job *
+__drm_sched_entity_queue_peek(struct drm_sched_entity *entity)
+{
+ struct spsc_node *node;
+
+ node = spsc_queue_peek(&entity->job_queue);
+ if (!node)
+ return NULL;
+
+ return container_of(node, struct drm_sched_job, queue_node);
+}
diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
index a48be16ab84f..43ca98e8db5f 100644
--- a/drivers/gpu/drm/scheduler/sched_main.c
+++ b/drivers/gpu/drm/scheduler/sched_main.c
@@ -78,6 +78,8 @@
#include <drm/gpu_scheduler.h>
#include <drm/spsc_queue.h>
+#include "sched_internal.h"
+
#define CREATE_TRACE_POINTS
#include "gpu_scheduler_trace.h"
@@ -87,9 +89,6 @@ static struct lockdep_map drm_sched_lockdep_map = {
};
#endif
-#define to_drm_sched_job(sched_job) \
- container_of((sched_job), struct drm_sched_job, queue_node)
-
int drm_sched_policy = DRM_SCHED_POLICY_FIFO;
/**
@@ -123,7 +122,7 @@ static bool drm_sched_can_queue(struct drm_gpu_scheduler *sched,
{
struct drm_sched_job *s_job;
- s_job = to_drm_sched_job(spsc_queue_peek(&entity->job_queue));
+ s_job = __drm_sched_entity_queue_peek(entity);
if (!s_job)
return false;
--
2.48.0
