Re: [PATCH v2] drm/xe: Don't restart parallel queues multiple times on GT reset

[Matthew Brost <matthew.brost@intel.com>]

On Tue, Oct 22, 2024 at 12:35:55PM +0200, Nirmoy Das wrote:
> In case of parallel submissions multiple GuC id will point to the
> same exec queue and on GT reset such exec queues will get restarted
> multiple times which is not desirable.
> 
> v2: don't use exec_queue_enabled() which could race,
>     do the same for xe_guc_submit_stop (Matt B)
> 
> Link: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/2295
> Cc: Jonathan Cavitt <jonathan.cavitt@intel.com>
> Cc: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
> Cc: Matthew Auld <matthew.auld@intel.com>
> Cc: Matthew Brost <matthew.brost@intel.com>

Reviewed-by: Matthew Brost <matthew.brost@intel.com>

> Cc: Tejas Upadhyay <tejas.upadhyay@intel.com>
> Signed-off-by: Nirmoy Das <nirmoy.das@intel.com>
> ---
>  drivers/gpu/drm/xe/xe_guc_submit.c | 14 ++++++++++++--
>  1 file changed, 12 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_guc_submit.c b/drivers/gpu/drm/xe/xe_guc_submit.c
> index 0b81972ff651..0a7c4cb9272d 100644
> --- a/drivers/gpu/drm/xe/xe_guc_submit.c
> +++ b/drivers/gpu/drm/xe/xe_guc_submit.c
> @@ -1745,8 +1745,13 @@ void xe_guc_submit_stop(struct xe_guc *guc)
>  
>  	mutex_lock(&guc->submission_state.lock);
>  
> -	xa_for_each(&guc->submission_state.exec_queue_lookup, index, q)
> +	xa_for_each(&guc->submission_state.exec_queue_lookup, index, q) {
> +		/* Prevent redundant attempts to stop parallel queues */
> +		if (q->guc->id != index)
> +			continue;
> +
>  		guc_exec_queue_stop(guc, q);
> +	}
>  
>  	mutex_unlock(&guc->submission_state.lock);
>  
> @@ -1784,8 +1789,13 @@ int xe_guc_submit_start(struct xe_guc *guc)
>  
>  	mutex_lock(&guc->submission_state.lock);
>  	atomic_dec(&guc->submission_state.stopped);
> -	xa_for_each(&guc->submission_state.exec_queue_lookup, index, q)
> +	xa_for_each(&guc->submission_state.exec_queue_lookup, index, q) {
> +		/* Prevent redundant attempts to start parallel queues */
> +		if (q->guc->id != index)
> +			continue;
> +
>  		guc_exec_queue_start(q);
> +	}
>  	mutex_unlock(&guc->submission_state.lock);
>  
>  	wake_up_all(&guc->ct.wq);
> -- 
> 2.46.0
>