Re: [PATCH v8 05/33] drm/xe: Return first unsignaled job first pending job helper

[Matthew Auld <matthew.auld@intel.com>]

On 07/10/2025 14:04, Matthew Brost wrote:
> In all cases where the first pending job helper is called, we only want
> to retrieve the first unsignaled pending job, as this helper is used
> exclusively in recovery flows. It is possible for signaled jobs to
> remain in the pending list as the scheduler is stopped, so those should
> be skipped.
> 
> Also, add kernel documentation to clarify this behavior.
> 
> v8:
>   - Split out into own patch (Auld)
> 
> Signed-off-by: Matthew Brost <matthew.brost@intel.com>

Reviewed-by: Matthew Auld <matthew.auld@intel.com>

> ---
>   drivers/gpu/drm/xe/xe_gpu_scheduler.h | 21 +++++++++++++++++----
>   1 file changed, 17 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_gpu_scheduler.h b/drivers/gpu/drm/xe/xe_gpu_scheduler.h
> index e548b2aed95a..3a9ff78d9346 100644
> --- a/drivers/gpu/drm/xe/xe_gpu_scheduler.h
> +++ b/drivers/gpu/drm/xe/xe_gpu_scheduler.h
> @@ -77,17 +77,30 @@ static inline void xe_sched_add_pending_job(struct xe_gpu_scheduler *sched,
>   	spin_unlock(&sched->base.job_list_lock);
>   }
>   
> +/**
> + * xe_sched_first_pending_job() - Find first pending job which is unsignaled
> + * @sched: Xe GPU scheduler
> + *
> + * Return first unsignaled job in pending list or NULL
> + */
>   static inline
>   struct xe_sched_job *xe_sched_first_pending_job(struct xe_gpu_scheduler *sched)
>   {
> -	struct xe_sched_job *job;
> +	struct xe_sched_job *job, *r_job = NULL;
>   
>   	spin_lock(&sched->base.job_list_lock);
> -	job = list_first_entry_or_null(&sched->base.pending_list,
> -				       struct xe_sched_job, drm.list);
> +	list_for_each_entry(job, &sched->base.pending_list, drm.list) {
> +		struct drm_sched_fence *s_fence = job->drm.s_fence;
> +		struct dma_fence *hw_fence = s_fence->parent;
> +
> +		if (hw_fence && !dma_fence_is_signaled(hw_fence)) {
> +			r_job = job;
> +			break;
> +		}
> +	}
>   	spin_unlock(&sched->base.job_list_lock);
>   
> -	return job;
> +	return r_job;
>   }
>   
>   static inline int