[Intel-gfx] [PATCH 02/13] drm/i915: Only queue requests during execlists submission

[Mika Kuoppala]

Chris Wilson <chris at chris-wilson.co.uk> writes:

> Leave the more complicated request dequeueing to the tasklet and instead
> just kick start the tasklet if we detect we are adding the first
> request.
>
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> ---
>  drivers/gpu/drm/i915/intel_lrc.c | 28 ++++------------------------
>  1 file changed, 4 insertions(+), 24 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
> index 6b49df4316f4..ca52b8e63305 100644
> --- a/drivers/gpu/drm/i915/intel_lrc.c
> +++ b/drivers/gpu/drm/i915/intel_lrc.c
> @@ -609,35 +609,15 @@ static void intel_lrc_irq_handler(unsigned long data)
>  static void execlists_submit_request(struct drm_i915_gem_request *request)
>  {
>  	struct intel_engine_cs *engine = request->engine;
> -	struct drm_i915_gem_request *cursor;
> -	int num_elements = 0;
>  
>  	spin_lock_bh(&engine->execlist_lock);
>  
> -	list_for_each_entry(cursor, &engine->execlist_queue, execlist_link)
> -		if (++num_elements > 2)
> -			break;
> -
> -	if (num_elements > 2) {
> -		struct drm_i915_gem_request *tail_req;
> -
> -		tail_req = list_last_entry(&engine->execlist_queue,
> -					   struct drm_i915_gem_request,
> -					   execlist_link);
> -
> -		if (request->ctx == tail_req->ctx) {
> -			WARN(tail_req->elsp_submitted != 0,
> -				"More than 2 already-submitted reqs queued\n");
> -			list_del(&tail_req->execlist_link);
> -			i915_gem_request_put(tail_req);
> -		}
> -	}
> -
>  	i915_gem_request_get(request);
> -	list_add_tail(&request->execlist_link, &engine->execlist_queue);
>  	request->ctx_hw_id = request->ctx->hw_id;
> -	if (num_elements == 0)
> -		execlists_unqueue(engine);
> +
> +	list_add_tail(&request->execlist_link, &engine->execlist_queue);
> +	if (request->execlist_link.prev == &engine->execlist_queue)

Why not list_first_entry()?

-Mika


> +		tasklet_hi_schedule(&engine->irq_tasklet);
>  
>  	spin_unlock_bh(&engine->execlist_lock);
>  }
> -- 
> 2.9.3