[Intel-gfx] [PATCH 09/13] drm/i915/execlists: Don't apply priority boost for resets

[Tvrtko Ursulin]

On 03/05/2019 12:52, Chris Wilson wrote:
> Do not treat reset as a normal preemption event and avoid giving the
> guilty request a priority boost for simply being active at the time of
> reset.
> 
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> ---
>   drivers/gpu/drm/i915/gt/intel_lrc.c | 16 +++++++++-------
>   1 file changed, 9 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
> index afcdfc440bbd..6419bcaf1ecc 100644
> --- a/drivers/gpu/drm/i915/gt/intel_lrc.c
> +++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
> @@ -371,11 +371,11 @@ static void unwind_wa_tail(struct i915_request *rq)
>   }
>   
>   static struct i915_request *
> -__unwind_incomplete_requests(struct intel_engine_cs *engine)
> +__unwind_incomplete_requests(struct intel_engine_cs *engine, int boost)
>   {
>   	struct i915_request *rq, *rn, *active = NULL;
>   	struct list_head *uninitialized_var(pl);
> -	int prio = I915_PRIORITY_INVALID | ACTIVE_PRIORITY;
> +	int prio = I915_PRIORITY_INVALID | boost;
>   
>   	lockdep_assert_held(&engine->timeline.lock);
>   
> @@ -419,8 +419,9 @@ __unwind_incomplete_requests(struct intel_engine_cs *engine)
>   	 * in the priority queue, but they will not gain immediate access to
>   	 * the GPU.
>   	 */
> -	if (~prio & ACTIVE_PRIORITY && __i915_request_has_started(active)) {
> -		prio |= ACTIVE_PRIORITY;
> +	if (~prio & boost && __i915_request_has_started(active)) {
> +		prio |= boost;
> +		GEM_BUG_ON(active->sched.attr.priority >= prio);
>   		active->sched.attr.priority = prio;
>   		list_move_tail(&active->sched.link,
>   			       i915_sched_lookup_priolist(engine, prio));
> @@ -435,7 +436,7 @@ execlists_unwind_incomplete_requests(struct intel_engine_execlists *execlists)
>   	struct intel_engine_cs *engine =
>   		container_of(execlists, typeof(*engine), execlists);
>   
> -	return __unwind_incomplete_requests(engine);
> +	return __unwind_incomplete_requests(engine, 0);
>   }
>   
>   static inline void
> @@ -656,7 +657,8 @@ static void complete_preempt_context(struct intel_engine_execlists *execlists)
>   	execlists_cancel_port_requests(execlists);
>   	__unwind_incomplete_requests(container_of(execlists,
>   						  struct intel_engine_cs,
> -						  execlists));
> +						  execlists),
> +				     ACTIVE_PRIORITY);
>   }
>   
>   static void execlists_dequeue(struct intel_engine_cs *engine)
> @@ -1909,7 +1911,7 @@ static void __execlists_reset(struct intel_engine_cs *engine, bool stalled)
>   	execlists_cancel_port_requests(execlists);
>   
>   	/* Push back any incomplete requests for replay after the reset. */
> -	rq = __unwind_incomplete_requests(engine);
> +	rq = __unwind_incomplete_requests(engine, 0);
>   	if (!rq)
>   		goto out_replay;
>   
> 

Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>

Regards,

Tvrtko