drm/sched: implement and export drm_sched_pick_best

Remove drm_sched_entity_get_free_sched() and use the logic of picking
the least loaded drm scheduler from a drm scheduler list to implement
drm_sched_pick_best(). This patch also exports drm_sched_pick_best() so
that it can be utilized by other drm drivers.

Signed-off-by: Nirmoy Das <nirmoy.das@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 36 insertions, 0 deletions

diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
index f4ac38b435f7..a18eabf692e4 100644
--- a/drivers/gpu/drm/scheduler/sched_main.c
+++ b/drivers/gpu/drm/scheduler/sched_main.c
@@ -697,6 +697,42 @@ drm_sched_get_cleanup_job(struct drm_gpu_scheduler *sched)
 }
 
 /**
+ * drm_sched_pick_best - Get a drm sched from a sched_list with the least load
+ * @sched_list: list of drm_gpu_schedulers
+ * @num_sched_list: number of drm_gpu_schedulers in the sched_list
+ *
+ * Returns pointer of the sched with the least load or NULL if none of the
+ * drm_gpu_schedulers are ready
+ */
+struct drm_gpu_scheduler *
+drm_sched_pick_best(struct drm_gpu_scheduler **sched_list,
+		     unsigned int num_sched_list)
+{
+	struct drm_gpu_scheduler *sched, *picked_sched = NULL;
+	int i;
+	unsigned int min_jobs = UINT_MAX, num_jobs;
+
+	for (i = 0; i < num_sched_list; ++i) {
+		sched = sched_list[i];
+
+		if (!sched->ready) {
+			DRM_WARN("scheduler %s is not ready, skipping",
+				 sched->name);
+			continue;
+		}
+
+		num_jobs = atomic_read(&sched->num_jobs);
+		if (num_jobs < min_jobs) {
+			min_jobs = num_jobs;
+			picked_sched = sched;
+		}
+	}
+
+	return picked_sched;
+}
+EXPORT_SYMBOL(drm_sched_pick_best);
+
+/**
  * drm_sched_blocked - check if the scheduler is blocked
  *
  * @sched: scheduler instance