[PATCH 09/18] drm/scheduler: use dma-fence annotations in main thread

Daniel Vetter
2020-06-04T08:12:48Z

If the scheduler rt thread gets stuck on a mutex that we're holding
while waiting for gpu workloads to complete, we have a problem.

Add dma-fence annotations so that lockdep can check this for us.

I've tried to quite carefully review this, and I think it's at the
right spot. But obviosly no expert on drm scheduler.

Cc: linux-media@vger.kernel.org
Cc: linaro-mm-sig@lists.linaro.org
Cc: linux-rdma@vger.kernel.org
Cc: amd-gfx@lists.freedesktop.org
Cc: intel-gfx@lists.freedesktop.org
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Christian König <christian.koenig@amd.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
---
drivers/gpu/drm/scheduler/sched_main.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
index 2f319102ae9f..06a736e506ad 100644
--- a/drivers/gpu/drm/scheduler/sched_main.c
+++ b/drivers/gpu/drm/scheduler/sched_main.c
@@ -763,9 +763,12 @@ static int drm_sched_main(void *param)
struct sched_param sparam = {.sched_priority = 1};
struct drm_gpu_scheduler *sched = (struct drm_gpu_scheduler *)param;
int r;
+ bool fence_cookie;

sched_setscheduler(current, SCHED_FIFO, &sparam);

+ fence_cookie = dma_fence_begin_signalling();
+
while (!kthread_should_stop()) {
struct drm_sched_entity *entity = NULL;
struct drm_sched_fence *s_fence;
@@ -823,6 +826,9 @@ static int drm_sched_main(void *param)

wake_up(&sched->job_scheduled);
}
+
+ dma_fence_end_signalling(fence_cookie);
+
return 0;
}

--
2.26.2