drm/amdgpu: add scheduler dependency callback v2

This way the scheduler doesn't wait in it's work thread any more.

v2: fix race conditions

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>

5 files changed, 55 insertions, 0 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
index aa2dcf578dd6..719506808b4a 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
@@ -717,6 +717,7 @@ int amdgpu_sync_resv(struct amdgpu_device *adev,
                      void *owner);
 int amdgpu_sync_rings(struct amdgpu_sync *sync,
                       struct amdgpu_ring *ring);
+struct fence *amdgpu_sync_get_fence(struct amdgpu_sync *sync);
 int amdgpu_sync_wait(struct amdgpu_sync *sync);
 void amdgpu_sync_free(struct amdgpu_device *adev, struct amdgpu_sync *sync,
                       struct fence *fence);
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_sched.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_sched.c
index f93fb3541488..de98fbd2971e 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_sched.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_sched.c
@@ -27,6 +27,12 @@
 #include <drm/drmP.h>
 #include "amdgpu.h"
 
+static struct fence *amdgpu_sched_dependency(struct amd_sched_job *job)
+{
+        struct amdgpu_job *sched_job = (struct amdgpu_job *)job;
+        return amdgpu_sync_get_fence(&sched_job->ibs->sync);
+}
+
 static struct fence *amdgpu_sched_run_job(struct amd_sched_job *job)
 {
         struct amdgpu_job *sched_job;
@@ -75,6 +81,7 @@ static void amdgpu_sched_process_job(struct amd_sched_job *job)
 }
 
 struct amd_sched_backend_ops amdgpu_sched_ops = {
+        .dependency = amdgpu_sched_dependency,
         .run_job = amdgpu_sched_run_job,
         .process_job = amdgpu_sched_process_job
 };
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_sync.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_sync.c
index 4fffb2539331..69b7d4540c6e 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_sync.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_sync.c
@@ -202,6 +202,28 @@ int amdgpu_sync_resv(struct amdgpu_device *adev,
         return r;
 }
 
+struct fence *amdgpu_sync_get_fence(struct amdgpu_sync *sync)
+{
+        struct amdgpu_sync_entry *e;
+        struct hlist_node *tmp;
+        struct fence *f;
+        int i;
+
+        hash_for_each_safe(sync->fences, i, tmp, e, node) {
+
+                f = e->fence;
+
+                hash_del(&e->node);
+                kfree(e);
+
+                if (!fence_is_signaled(f))
+                        return f;
+
+                fence_put(f);
+        }
+        return NULL;
+}
+
 int amdgpu_sync_wait(struct amdgpu_sync *sync)
 {
         struct amdgpu_sync_entry *e;
diff --git a/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c b/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c
index 205cb887d023..2f5d1f0da8e5 100644
--- a/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c
+++ b/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c
@@ -192,14 +192,36 @@ void amd_sched_entity_fini(struct amd_gpu_scheduler *sched,
         kfifo_free(&entity->job_queue);
 }
 
+static void amd_sched_entity_wakeup(struct fence *f, struct fence_cb *cb)
+{
+        struct amd_sched_entity *entity =
+                container_of(cb, struct amd_sched_entity, cb);
+        entity->dependency = NULL;
+        fence_put(f);
+        amd_sched_wakeup(entity->scheduler);
+}
+
 static struct amd_sched_job *
 amd_sched_entity_pop_job(struct amd_sched_entity *entity)
 {
+        struct amd_gpu_scheduler *sched = entity->scheduler;
         struct amd_sched_job *job;
 
+        if (ACCESS_ONCE(entity->dependency))
+                return NULL;
+
         if (!kfifo_out_peek(&entity->job_queue, &job, sizeof(job)))
                 return NULL;
 
+        while ((entity->dependency = sched->ops->dependency(job))) {
+
+                if (fence_add_callback(entity->dependency, &entity->cb,
+                                       amd_sched_entity_wakeup))
+                        fence_put(entity->dependency);
+                else
+                        return NULL;
+        }
+
         return job;
 }
 
diff --git a/drivers/gpu/drm/amd/scheduler/gpu_scheduler.h b/drivers/gpu/drm/amd/scheduler/gpu_scheduler.h
index e797796dcad7..2af0e4d4d817 100644
--- a/drivers/gpu/drm/amd/scheduler/gpu_scheduler.h
+++ b/drivers/gpu/drm/amd/scheduler/gpu_scheduler.h
@@ -45,6 +45,8 @@ struct amd_sched_entity {
         spinlock_t                      queue_lock;
         struct amd_gpu_scheduler        *scheduler;
         uint64_t                        fence_context;
+        struct fence                    *dependency;
+        struct fence_cb                 cb;
 };
 
 /**
@@ -89,6 +91,7 @@ static inline struct amd_sched_fence *to_amd_sched_fence(struct fence *f)
  * these functions should be implemented in driver side
 */
 struct amd_sched_backend_ops {
+        struct fence *(*dependency)(struct amd_sched_job *job);
         struct fence *(*run_job)(struct amd_sched_job *job);
         void (*process_job)(struct amd_sched_job *job);
 };