Re: [PATCH v2 23/23] drm/sched: Add (optional) fence signaling annotation

Luben Tuikov
2023-03-21T02:56:06Z

This is good. Hopefully it helps us catch lockdep bugs.

Reviewed-by: Luben Tuikov <luben.tuikov@amd.com>

Regards,
Luben

On 2023-03-20 10:43, Rob Clark wrote:
> From: Rob Clark <robdclark@chromium.org>
>
> Based on
> https://lore.kernel.org/dri-devel/20200604081224.863494-10-daniel.vetter@ffwll.ch/
> but made to be optional.
>
> Signed-off-by: Rob Clark <robdclark@chromium.org>
> ---
> drivers/gpu/drm/msm/msm_ringbuffer.c | 1 +
> drivers/gpu/drm/scheduler/sched_main.c | 9 +++++++++
> include/drm/gpu_scheduler.h | 2 ++
> 3 files changed, 12 insertions(+)
>
> diff --git a/drivers/gpu/drm/msm/msm_ringbuffer.c b/drivers/gpu/drm/msm/msm_ringbuffer.c
> index b60199184409..7e42baf16cd0 100644
> --- a/drivers/gpu/drm/msm/msm_ringbuffer.c
> +++ b/drivers/gpu/drm/msm/msm_ringbuffer.c
> @@ -93,6 +93,7 @@ struct msm_ringbuffer *msm_ringbuffer_new(struct msm_gpu *gpu, int id,
> /* currently managing hangcheck ourselves: */
> sched_timeout = MAX_SCHEDULE_TIMEOUT;
>
> + ring->sched.fence_signaling = true;
> ret = drm_sched_init(&ring->sched, &msm_sched_ops,
> num_hw_submissions, 0, sched_timeout,
> NULL, NULL, to_msm_bo(ring->bo)->name, gpu->dev->dev);
> diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
> index 4e6ad6e122bc..c2ee44d6224b 100644
> --- a/drivers/gpu/drm/scheduler/sched_main.c
> +++ b/drivers/gpu/drm/scheduler/sched_main.c
> @@ -978,10 +978,15 @@ static bool drm_sched_blocked(struct drm_gpu_scheduler *sched)
> static int drm_sched_main(void *param)
> {
> struct drm_gpu_scheduler *sched = (struct drm_gpu_scheduler *)param;
> + const bool fence_signaling = sched->fence_signaling;
> + bool fence_cookie;
> int r;
>
> sched_set_fifo_low(current);
>
> + if (fence_signaling)
> + fence_cookie = dma_fence_begin_signalling();
> +
> while (!kthread_should_stop()) {
> struct drm_sched_entity *entity = NULL;
> struct drm_sched_fence *s_fence;
> @@ -1039,6 +1044,10 @@ static int drm_sched_main(void *param)
>
> wake_up(&sched->job_scheduled);
> }
> +
> + if (fence_signaling)
> + dma_fence_end_signalling(fence_cookie);
> +
> return 0;
> }
>
> diff --git a/include/drm/gpu_scheduler.h b/include/drm/gpu_scheduler.h
> index 9db9e5e504ee..8f23ea522e22 100644
> --- a/include/drm/gpu_scheduler.h
> +++ b/include/drm/gpu_scheduler.h
> @@ -483,6 +483,7 @@ struct drm_sched_backend_ops {
> * @ready: marks if the underlying HW is ready to work
> * @free_guilty: A hit to time out handler to free the guilty job.
> * @dev: system &struct device
> + * @fence_signaling: Opt in to fence signaling annotations
> *
> * One scheduler is implemented for each hardware ring.
> */
> @@ -507,6 +508,7 @@ struct drm_gpu_scheduler {
> bool ready;
> bool free_guilty;
> struct device *dev;
> + bool fence_signaling;
> };
>
> int drm_sched_init(struct drm_gpu_scheduler *sched,