drm/scheduler: add new function to get least loaded sched v2

The function selects the run queue from the rq_list with the
least load. The load is decided by the number of jobs in a
scheduler.

v2: avoid using atomic read twice consecutively, instead store
    it locally

Signed-off-by: Nayan Deshmukh <nayan26deshmukh@gmail.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/scheduler/gpu_scheduler.c b/drivers/gpu/drm/scheduler/gpu_scheduler.c
index 3b99691909270a6202a0d4a9813c53636b270759..3e13bdfa8710d1576a8ad983000fd4d37c401eb7 100644 (file)
--- a/drivers/gpu/drm/scheduler/gpu_scheduler.c
+++ b/drivers/gpu/drm/scheduler/gpu_scheduler.c
@@ -241,6 +241,31 @@ static bool drm_sched_entity_is_ready(struct drm_sched_entity *entity)
        return true;
 }
 
+/**
+ * drm_sched_entity_get_free_sched - Get the rq from rq_list with least load
+ *
+ * @entity: scheduler entity
+ *
+ * Return the pointer to the rq with least load.
+ */
+static struct drm_sched_rq *
+drm_sched_entity_get_free_sched(struct drm_sched_entity *entity)
+{
+       struct drm_sched_rq *rq = NULL;
+       unsigned int min_jobs = UINT_MAX, num_jobs;
+       int i;
+
+       for (i = 0; i < entity->num_rq_list; ++i) {
+               num_jobs = atomic_read(&entity->rq_list[i]->sched->num_jobs);
+               if (num_jobs < min_jobs) {
+                       min_jobs = num_jobs;
+                       rq = entity->rq_list[i];
+               }
+       }
+
+       return rq;
+}
+
 static void drm_sched_entity_kill_jobs_cb(struct dma_fence *f,
                                    struct dma_fence_cb *cb)
 {