drm/amdgpu: let the scheduler work more with jobs v2

v2: fix another race condition

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Chunming Zhou <david1.zhou@amd.com>
Reviewed-by: Jammy Zhou <Jammy.Zhou@amd.com>

1 files changed, 37 insertions, 24 deletions

diff --git a/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c b/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c
index d99fe90991dc..205cb887d023 100644
--- a/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c
+++ b/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c
@@ -27,6 +27,8 @@
 #include <drm/drmP.h>
 #include "gpu_scheduler.h"
 
+static struct amd_sched_job *
+amd_sched_entity_pop_job(struct amd_sched_entity *entity);
 static void amd_sched_wakeup(struct amd_gpu_scheduler *sched);
 
 /* Initialize a given run queue struct */
@@ -56,34 +58,36 @@ static void amd_sched_rq_remove_entity(struct amd_sched_rq *rq,
 }
 
 /**
- * Select next entity from a specified run queue with round robin policy.
- * It could return the same entity as current one if current is the only
- * available one in the queue. Return NULL if nothing available.
+ * Select next job from a specified run queue with round robin policy.
+ * Return NULL if nothing available.
  */
-static struct amd_sched_entity *
-amd_sched_rq_select_entity(struct amd_sched_rq *rq)
+static struct amd_sched_job *
+amd_sched_rq_select_job(struct amd_sched_rq *rq)
 {
         struct amd_sched_entity *entity;
+        struct amd_sched_job *job;
 
         spin_lock(&rq->lock);
 
         entity = rq->current_entity;
         if (entity) {
                 list_for_each_entry_continue(entity, &rq->entities, list) {
-                        if (!kfifo_is_empty(&entity->job_queue)) {
+                        job = amd_sched_entity_pop_job(entity);
+                        if (job) {
                                 rq->current_entity = entity;
                                 spin_unlock(&rq->lock);
-                                return rq->current_entity;
+                                return job;
                         }
                 }
         }
 
         list_for_each_entry(entity, &rq->entities, list) {
 
-                if (!kfifo_is_empty(&entity->job_queue)) {
+                job = amd_sched_entity_pop_job(entity);
+                if (job) {
                         rq->current_entity = entity;
                         spin_unlock(&rq->lock);
-                        return rq->current_entity;
+                        return job;
                 }
 
                 if (entity == rq->current_entity)
@@ -188,6 +192,17 @@ void amd_sched_entity_fini(struct amd_gpu_scheduler *sched,
         kfifo_free(&entity->job_queue);
 }
 
+static struct amd_sched_job *
+amd_sched_entity_pop_job(struct amd_sched_entity *entity)
+{
+        struct amd_sched_job *job;
+
+        if (!kfifo_out_peek(&entity->job_queue, &job, sizeof(job)))
+                return NULL;
+
+        return job;
+}
+
 /**
  * Helper to submit a job to the job queue
  *
@@ -260,22 +275,22 @@ static void amd_sched_wakeup(struct amd_gpu_scheduler *sched)
 }
 
 /**
- * Select next entity containing real IB submissions
+ * Select next to run
 */
-static struct amd_sched_entity *
-amd_sched_select_context(struct amd_gpu_scheduler *sched)
+static struct amd_sched_job *
+amd_sched_select_job(struct amd_gpu_scheduler *sched)
 {
-        struct amd_sched_entity *tmp;
+        struct amd_sched_job *job;
 
         if (!amd_sched_ready(sched))
                 return NULL;
 
         /* Kernel run queue has higher priority than normal run queue*/
-        tmp = amd_sched_rq_select_entity(&sched->kernel_rq);
-        if (tmp == NULL)
-                tmp = amd_sched_rq_select_entity(&sched->sched_rq);
+        job = amd_sched_rq_select_job(&sched->kernel_rq);
+        if (job == NULL)
+                job = amd_sched_rq_select_job(&sched->sched_rq);
 
-        return tmp;
+        return job;
 }
 
 static void amd_sched_process_job(struct fence *f, struct fence_cb *cb)
@@ -301,22 +316,19 @@ static int amd_sched_main(void *param)
         sched_setscheduler(current, SCHED_FIFO, &sparam);
 
         while (!kthread_should_stop()) {
-                struct amd_sched_entity *c_entity = NULL;
+                struct amd_sched_entity *entity;
                 struct amd_sched_job *job;
                 struct fence *fence;
 
                 wait_event_interruptible(sched->wake_up_worker,
                         kthread_should_stop() ||
-                        (c_entity = amd_sched_select_context(sched)));
+                        (job = amd_sched_select_job(sched)));
 
-                if (!c_entity)
+                if (!job)
                         continue;
 
-                r = kfifo_out(&c_entity->job_queue, &job, sizeof(void *));
-                if (r != sizeof(void *))
-                        continue;
+                entity = job->s_entity;
                 atomic_inc(&sched->hw_rq_count);
-
                 fence = sched->ops->run_job(job);
                 if (fence) {
                         r = fence_add_callback(fence, &job->cb,
@@ -328,6 +340,7 @@ static int amd_sched_main(void *param)
                         fence_put(fence);
                 }
 
+                kfifo_out(&entity->job_queue, &job, sizeof(job));
                 wake_up(&sched->job_scheduled);
         }
         return 0;