linux-kernel - Re: [PATCH] drm/sched/tests: Make timedout

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Message-ID: <79ba97ca2c04b7707b9641fbb89715873c11c979.camel@mailbox.org>
Date: Mon, 23 Jun 2025 11:00:11 +0200
From: Philipp Stanner <phasta@...lbox.org>
To: Philipp Stanner <phasta@...nel.org>, Matthew Brost
 <matthew.brost@...el.com>,  Danilo Krummrich <dakr@...nel.org>, Christian
 König <ckoenig.leichtzumerken@...il.com>, Maarten
 Lankhorst <maarten.lankhorst@...ux.intel.com>, Maxime Ripard
 <mripard@...nel.org>,  Thomas Zimmermann <tzimmermann@...e.de>, David
 Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>, Tvrtko Ursulin
 <tvrtko.ursulin@...lia.com>, Pierre-Eric Pelloux-Prayer
 <pierre-eric.pelloux-prayer@....com>
Cc: dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] drm/sched/tests: Make timedout_job callback a better
 role model

On Thu, 2025-06-05 at 15:41 +0200, Philipp Stanner wrote:
> Since the drm_mock_scheduler does not have real users in userspace,
> nor
> does it have real hardware or firmware rings, it's not necessary to
> signal timedout fences nor free jobs - from a functional standpoint.
> 
> The unit tests, however, serve as a reference implementation and a
> first
> example for new scheduler users. Therefore, they should approximate
> the
> canonical usage as much as possible.
> 
> Make sure timed out hardware fences get signaled with the appropriate
> error code.
> 
> Signed-off-by: Philipp Stanner <phasta@...nel.org>

Any further objections with me merging this?

P.


> ---
>  .../gpu/drm/scheduler/tests/mock_scheduler.c  | 26
> ++++++++++++++++++-
>  1 file changed, 25 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/scheduler/tests/mock_scheduler.c
> b/drivers/gpu/drm/scheduler/tests/mock_scheduler.c
> index 7f947ab9d322..49d067fecd67 100644
> --- a/drivers/gpu/drm/scheduler/tests/mock_scheduler.c
> +++ b/drivers/gpu/drm/scheduler/tests/mock_scheduler.c
> @@ -200,12 +200,36 @@ static struct dma_fence
> *mock_sched_run_job(struct drm_sched_job *sched_job)
>  	return &job->hw_fence;
>  }
>  
> +/*
> + * Normally, drivers would take appropriate measures in this
> callback, such as
> + * killing the entity the faulty job is associated with, resetting
> the hardware
> + * and / or resubmitting non-faulty jobs.
> + *
> + * For the mock scheduler, there are no hardware rings to be
> resetted nor jobs
> + * to be resubmitted. Thus, this function merely ensures that
> + *   a) timedout fences get signaled properly and removed from the
> pending list
> + *   b) the mock scheduler framework gets informed about the timeout
> via a flag
> + *   c) The drm_sched_job, not longer needed, gets freed
> + */
>  static enum drm_gpu_sched_stat
>  mock_sched_timedout_job(struct drm_sched_job *sched_job)
>  {
> +	struct drm_mock_scheduler *sched =
> drm_sched_to_mock_sched(sched_job->sched);
>  	struct drm_mock_sched_job *job =
> drm_sched_job_to_mock_job(sched_job);
> +	unsigned long flags;
>  
> -	job->flags |= DRM_MOCK_SCHED_JOB_TIMEDOUT;
> +	spin_lock_irqsave(&sched->lock, flags);
> +	if (!dma_fence_is_signaled_locked(&job->hw_fence)) {
> +		list_del(&job->link);
> +		job->flags |= DRM_MOCK_SCHED_JOB_TIMEDOUT;
> +		dma_fence_set_error(&job->hw_fence, -ETIMEDOUT);
> +		dma_fence_signal_locked(&job->hw_fence);
> +	}
> +	spin_unlock_irqrestore(&sched->lock, flags);
> +
> +	dma_fence_put(&job->hw_fence);
> +	drm_sched_job_cleanup(sched_job);
> +	/* Mock job itself is freed by the kunit framework. */
>  
>  	return DRM_GPU_SCHED_STAT_NOMINAL;
>  }