Re: [PATCH 13/16] drm/xe/multi_queue: Support active group after primary is destroyed

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

On Fri, Oct 31, 2025 at 11:29:33AM -0700, Niranjana Vishwanathapura wrote:
> Add support to keep the group active after the primary queue is
> destroyed. Instead of killing the primary queue during exec_queue
> destroy ioctl, kill it when all the secondary queues of the group
> are killed.
> 
> Signed-off-by: Niranjana Vishwanathapura <niranjana.vishwanathapura@intel.com>
> ---
>  drivers/gpu/drm/xe/xe_device.c           |  7 ++-
>  drivers/gpu/drm/xe/xe_exec_queue.c       | 55 +++++++++++++++++++++++-
>  drivers/gpu/drm/xe/xe_exec_queue.h       |  2 +
>  drivers/gpu/drm/xe/xe_exec_queue_types.h |  4 ++
>  include/uapi/drm/xe_drm.h                |  5 +++
>  5 files changed, 70 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_device.c b/drivers/gpu/drm/xe/xe_device.c
> index 0b496676527a..708a17c357e6 100644
> --- a/drivers/gpu/drm/xe/xe_device.c
> +++ b/drivers/gpu/drm/xe/xe_device.c
> @@ -176,7 +176,12 @@ static void xe_file_close(struct drm_device *dev, struct drm_file *file)
>  	xa_for_each(&xef->exec_queue.xa, idx, q) {
>  		if (q->vm && q->hwe->hw_engine_group)
>  			xe_hw_engine_group_del_exec_queue(q->hwe->hw_engine_group, q);
> -		xe_exec_queue_kill(q);
> +
> +		if (xe_exec_queue_is_multi_queue_primary(q))
> +			xe_exec_queue_group_kill_put(q->multi_queue.group);
> +		else
> +			xe_exec_queue_kill(q);
> +
>  		xe_exec_queue_put(q);
>  	}
>  	xa_for_each(&xef->vm.xa, idx, vm)
> diff --git a/drivers/gpu/drm/xe/xe_exec_queue.c b/drivers/gpu/drm/xe/xe_exec_queue.c
> index 3c1bb4f10fd5..d7b0173691c1 100644
> --- a/drivers/gpu/drm/xe/xe_exec_queue.c
> +++ b/drivers/gpu/drm/xe/xe_exec_queue.c
> @@ -405,6 +405,26 @@ struct xe_exec_queue *xe_exec_queue_create_bind(struct xe_device *xe,
>  }
>  ALLOW_ERROR_INJECTION(xe_exec_queue_create_bind, ERRNO);
>  
> +static void xe_exec_queue_group_kill(struct kref *ref)
> +{
> +	struct xe_exec_queue_group *group = container_of(ref, struct xe_exec_queue_group,
> +							 kill_refcount);
> +	xe_exec_queue_kill(group->primary);
> +}
> +
> +static inline void xe_exec_queue_group_kill_get(struct xe_exec_queue_group *group)
> +{
> +	kref_get(&group->kill_refcount);
> +}
> +
> +void xe_exec_queue_group_kill_put(struct xe_exec_queue_group *group)
> +{
> +	if (!group)
> +		return;
> +
> +	kref_put(&group->kill_refcount, xe_exec_queue_group_kill);
> +}
> +
>  void xe_exec_queue_destroy(struct kref *ref)
>  {
>  	struct xe_exec_queue *q = container_of(ref, struct xe_exec_queue, refcount);
> @@ -607,6 +627,7 @@ static int xe_exec_queue_group_init(struct xe_device *xe, struct xe_exec_queue *
>  	group->primary = q;
>  	group->cgp_bo = bo;
>  	INIT_LIST_HEAD(&group->list);
> +	kref_init(&group->kill_refcount);
>  	xa_init_flags(&group->xa, XA_FLAGS_ALLOC1);
>  	mutex_init(&group->lock);
>  	mutex_init(&group->list_lock);
> @@ -675,6 +696,11 @@ static int xe_exec_queue_group_add(struct xe_device *xe, struct xe_exec_queue *q
>  	q->multi_queue.pos = pos;
>  	mutex_unlock(&group->lock);
>  
> +	if (group->primary->multi_queue.keep_active) {
> +		xe_exec_queue_group_kill_get(group);
> +		q->multi_queue.keep_active = true;
> +	}
> +
>  	return 0;
>  }
>  
> @@ -691,6 +717,11 @@ static void xe_exec_queue_group_delete(struct xe_exec_queue *q)
>  	if (lrc)
>  		xe_lrc_put(lrc);
>  	mutex_unlock(&group->lock);
> +
> +	if (q->multi_queue.keep_active) {
> +		xe_exec_queue_group_kill_put(group);
> +		q->multi_queue.keep_active = false;
> +	}
>  }
>  
>  static int exec_queue_set_multi_group(struct xe_device *xe, struct xe_exec_queue *q,
> @@ -709,12 +740,24 @@ static int exec_queue_set_multi_group(struct xe_device *xe, struct xe_exec_queue
>  		return -EINVAL;
>  
>  	if (value & DRM_XE_MULTI_GROUP_CREATE) {
> -		if (XE_IOCTL_DBG(xe, value & ~DRM_XE_MULTI_GROUP_CREATE))
> +		if (XE_IOCTL_DBG(xe, value & ~(DRM_XE_MULTI_GROUP_CREATE |
> +					       DRM_XE_MULTI_GROUP_KEEP_ACTIVE)))
> +			return -EINVAL;
> +
> +		/*
> +		 * KEEP_ACTIVE is not supported in preempt fence mode as in that mode,
> +		 * VM_DESTROY ioctl expects all exec queues of that VM are already killed.
> +		 */
> +		if (XE_IOCTL_DBG(xe, (value & DRM_XE_MULTI_GROUP_KEEP_ACTIVE) &&
> +				 xe_vm_in_preempt_fence_mode(q->vm)))
>  			return -EINVAL;
>  
>  		q->multi_queue.valid = true;
>  		q->multi_queue.is_primary = true;
>  		q->multi_queue.pos = 0;
> +		if (value & DRM_XE_MULTI_GROUP_KEEP_ACTIVE)
> +			q->multi_queue.keep_active = true;
> +
>  		return 0;
>  	}
>  
> @@ -1254,6 +1297,11 @@ void xe_exec_queue_kill(struct xe_exec_queue *q)
>  
>  	q->ops->kill(q);
>  	xe_vm_remove_compute_exec_queue(q->vm, q);
> +
> +	if (!xe_exec_queue_is_multi_queue_primary(q) && q->multi_queue.keep_active) {
> +		xe_exec_queue_group_kill_put(q->multi_queue.group);
> +		q->multi_queue.keep_active = false;
> +	}

This looks a little odd. Either you don't need to clear
multi_queue.keep_active as xe_exec_queue_kill can be called at most once
(IIRC it can be called multiple times) or you need some locking around
multi_queue.keep_active or it needs to be an atomic to prevent multiple
threads from calling xe_exec_queue_group_kill_put twice.

Matt

>  }
>  
>  int xe_exec_queue_destroy_ioctl(struct drm_device *dev, void *data,
> @@ -1280,7 +1328,10 @@ int xe_exec_queue_destroy_ioctl(struct drm_device *dev, void *data,
>  	if (q->vm && q->hwe->hw_engine_group)
>  		xe_hw_engine_group_del_exec_queue(q->hwe->hw_engine_group, q);
>  
> -	xe_exec_queue_kill(q);
> +	if (xe_exec_queue_is_multi_queue_primary(q))
> +		xe_exec_queue_group_kill_put(q->multi_queue.group);
> +	else
> +		xe_exec_queue_kill(q);
>  
>  	trace_xe_exec_queue_close(q);
>  	xe_exec_queue_put(q);
> diff --git a/drivers/gpu/drm/xe/xe_exec_queue.h b/drivers/gpu/drm/xe/xe_exec_queue.h
> index 61478b2e883b..b642341f1ede 100644
> --- a/drivers/gpu/drm/xe/xe_exec_queue.h
> +++ b/drivers/gpu/drm/xe/xe_exec_queue.h
> @@ -109,6 +109,8 @@ static inline struct xe_exec_queue *xe_exec_queue_multi_queue_primary(struct xe_
>  	return xe_exec_queue_is_multi_queue(q) ? q->multi_queue.group->primary : q;
>  }
>  
> +void xe_exec_queue_group_kill_put(struct xe_exec_queue_group *group);
> +
>  bool xe_exec_queue_is_lr(struct xe_exec_queue *q);
>  
>  bool xe_exec_queue_is_idle(struct xe_exec_queue *q);
> diff --git a/drivers/gpu/drm/xe/xe_exec_queue_types.h b/drivers/gpu/drm/xe/xe_exec_queue_types.h
> index e64b6588923e..cdca3afe838c 100644
> --- a/drivers/gpu/drm/xe/xe_exec_queue_types.h
> +++ b/drivers/gpu/drm/xe/xe_exec_queue_types.h
> @@ -55,6 +55,8 @@ struct xe_exec_queue_group {
>  	struct list_head list;
>  	/** @list_lock: Secondary queue list lock */
>  	struct mutex list_lock;
> +	/** @kill_refcount: ref count to kill primary queue */
> +	struct kref kill_refcount;
>  	/** @sync_pending: CGP_SYNC_DONE g2h response pending */
>  	bool sync_pending;
>  };
> @@ -152,6 +154,8 @@ struct xe_exec_queue {
>  		u8 valid:1;
>  		/** @multi_queue.is_primary: Is primary queue (Q0) of the group */
>  		u8 is_primary:1;
> +		/** @multi_queue.keep_active: Keep the group active after primary is destroyed */
> +		u8 keep_active:1;
>  	} multi_queue;
>  
>  	/** @sched_props: scheduling properties */
> diff --git a/include/uapi/drm/xe_drm.h b/include/uapi/drm/xe_drm.h
> index d72151163e77..333fb38b3404 100644
> --- a/include/uapi/drm/xe_drm.h
> +++ b/include/uapi/drm/xe_drm.h
> @@ -1260,6 +1260,10 @@ struct drm_xe_vm_bind {
>   *    then a new multi-queue group is created with this queue as the primary queue
>   *    (Q0). Otherwise, the queue gets added to the multi-queue group whose primary
>   *    queue id is specified in the 'value' field.
> + *    If the extension's 'value' field has %DRM_XE_MULTI_GROUP_KEEP_ACTIVE flag
> + *    set, then the multi-queue group is kept active after the primary queue is
> + *    destroyed.
> + *
>   *  - %DRM_XE_EXEC_QUEUE_SET_PROPERTY_MULTI_QUEUE_PRIORITY - Set the queue
>   *    priority within the multi-queue group.
>   *
> @@ -1304,6 +1308,7 @@ struct drm_xe_exec_queue_create {
>  #define   DRM_XE_EXEC_QUEUE_SET_PROPERTY_PXP_TYPE		2
>  #define   DRM_XE_EXEC_QUEUE_SET_PROPERTY_MULTI_GROUP		3
>  #define     DRM_XE_MULTI_GROUP_CREATE				(1ull << 63)
> +#define     DRM_XE_MULTI_GROUP_KEEP_ACTIVE			(1ull << 62)
>  #define   DRM_XE_EXEC_QUEUE_SET_PROPERTY_MULTI_QUEUE_PRIORITY	4
>  	/** @extensions: Pointer to the first extension struct, if any */
>  	__u64 extensions;
> -- 
> 2.43.0
>