[Intel-gfx] [PATCH 1/3] drm/i915/execlists: Mark up priority boost on preemption

[Tvrtko Ursulin]

On 23/01/2019 12:36, Chris Wilson wrote:
> Record the priority boost we giving to the preempted client or else we
> may end up in a situation where the priority queue no longer matches the
> request priority order and so we can end up in an infinite loop of
> preempting the same pair of requests.
> 
> Fixes: e9eaf82d97a2 ("drm/i915: Priority boost for waiting clients")
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> ---
>   drivers/gpu/drm/i915/intel_lrc.c | 4 ++++
>   1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
> index 436e59724900..8aa8a4862543 100644
> --- a/drivers/gpu/drm/i915/intel_lrc.c
> +++ b/drivers/gpu/drm/i915/intel_lrc.c
> @@ -302,6 +302,7 @@ static void __unwind_incomplete_requests(struct intel_engine_cs *engine)
>   	 */
>   	if (!(prio & I915_PRIORITY_NEWCLIENT)) {
>   		prio |= I915_PRIORITY_NEWCLIENT;
> +		active->sched.attr.priority = prio;
>   		list_move_tail(&active->sched.link,
>   			       i915_sched_lookup_priolist(engine, prio));
>   	}
> @@ -625,6 +626,9 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
>   		int i;
>   
>   		priolist_for_each_request_consume(rq, rn, p, i) {
> +			GEM_BUG_ON(last &&
> +				   need_preempt(engine, last, rq_prio(rq)));
> +
>   			/*
>   			 * Can we combine this request with the current port?
>   			 * It has to be the same context/ringbuffer and not
> 

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

Regards,

Tvrtko