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

[Cavitt, Jonathan]

-----Original Message-----
From: Intel-xe <intel-xe-bounces at lists.freedesktop.org> On Behalf Of Nirmoy Das
Sent: Monday, October 21, 2024 2:12 PM
To: intel-xe at lists.freedesktop.org
Cc: Das, Nirmoy <nirmoy.das at intel.com>; Ghimiray, Himal Prasad <himal.prasad.ghimiray at intel.com>; Auld, Matthew <matthew.auld at intel.com>; Brost, Matthew <matthew.brost at intel.com>; Upadhyay, Tejas <tejas.upadhyay at intel.com>
Subject: [PATCH] drm/xe: Don't restart parallel queues multiple times on GT reset
> 
> 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.
> 
> Link: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/2295
> Cc: Himal Prasad Ghimiray <himal.prasad.ghimiray at intel.com>
> Cc: Matthew Auld <matthew.auld at intel.com>
> Cc: Matthew Brost <matthew.brost at intel.com>
> Cc: Tejas Upadhyay <tejas.upadhyay at intel.com>
> Signed-off-by: Nirmoy Das <nirmoy.das at intel.com>

This makes sense, though I'd assume we'd want at least one of
the GuC IDs to restart the exec queue during a GT reset.  Is that
what exec_queue_enabled helps allow?

I won't block on it presently, just was curious if that case was being
handled, or if we didn't need to worry about it.

Reviewed-by: Jonathan Cavitt <jonathan.cavitt at intel.com>
-Jonathan Cavitt

> ---
>  drivers/gpu/drm/xe/xe_guc_submit.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_guc_submit.c b/drivers/gpu/drm/xe/xe_guc_submit.c
> index 0b81972ff651..6aeb007eaf06 100644
> --- a/drivers/gpu/drm/xe/xe_guc_submit.c
> +++ b/drivers/gpu/drm/xe/xe_guc_submit.c
> @@ -1784,8 +1784,13 @@ 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) {
> +		/* Skip restarting parallel queues */
> +		if (exec_queue_enabled(q) && xe_exec_queue_is_parallel(q))
> +			continue;
> +
>  		guc_exec_queue_start(q);
> +	}
>  	mutex_unlock(&guc->submission_state.lock);
>  
>  	wake_up_all(&guc->ct.wq);
> -- 
> 2.46.0
> 
>