[Intel-gfx] [PATCH 05/51] drm/i915/guc: Add bypass tasklet submission path to GuC

Matthew Brost
2021-07-16T20:00:34Z

Add bypass tasklet submission path to GuC. The tasklet is only used if H2G
channel has backpresure.

Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: John Harrison <John.C.Harrison@Intel.com>
---
.../gpu/drm/i915/gt/uc/intel_guc_submission.c | 37 +++++++++++++++----
1 file changed, 29 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
index ca0717166a27..53b4a5eb4a85 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
@@ -172,6 +172,12 @@ static int guc_add_request(struct intel_guc *guc, struct i915_request *rq)
return err;
}

+static inline void guc_set_lrc_tail(struct i915_request *rq)
+{
+ rq->context->lrc_reg_state[CTX_RING_TAIL] =
+ intel_ring_set_tail(rq->ring, rq->tail);
+}
+
static inline int rq_prio(const struct i915_request *rq)
{
return rq->sched.attr.priority;
@@ -215,8 +221,7 @@ static int guc_dequeue_one_context(struct intel_guc *guc)
}
done:
if (submit) {
- last->context->lrc_reg_state[CTX_RING_TAIL] =
- intel_ring_set_tail(last->ring, last->tail);
+ guc_set_lrc_tail(last);
resubmit:
/*
* We only check for -EBUSY here even though it is possible for
@@ -496,20 +501,36 @@ static inline void queue_request(struct i915_sched_engine *sched_engine,
set_bit(I915_FENCE_FLAG_PQUEUE, &rq->fence.flags);
}

+static int guc_bypass_tasklet_submit(struct intel_guc *guc,
+ struct i915_request *rq)
+{
+ int ret;
+
+ __i915_request_submit(rq);
+
+ trace_i915_request_in(rq, 0);
+
+ guc_set_lrc_tail(rq);
+ ret = guc_add_request(guc, rq);
+ if (ret == -EBUSY)
+ guc->stalled_request = rq;
+
+ return ret;
+}
+
static void guc_submit_request(struct i915_request *rq)
{
struct i915_sched_engine *sched_engine = rq->engine->sched_engine;
+ struct intel_guc *guc = &rq->engine->gt->uc.guc;
unsigned long flags;

/* Will be called from irq-context when using foreign fences. */
spin_lock_irqsave(&sched_engine->lock, flags);

- queue_request(sched_engine, rq, rq_prio(rq));
-
- GEM_BUG_ON(i915_sched_engine_is_empty(sched_engine));
- GEM_BUG_ON(list_empty(&rq->sched.link));
-
- tasklet_hi_schedule(&sched_engine->tasklet);
+ if (guc->stalled_request || !i915_sched_engine_is_empty(sched_engine))
+ queue_request(sched_engine, rq, rq_prio(rq));
+ else if (guc_bypass_tasklet_submit(guc, rq) == -EBUSY)
+ tasklet_hi_schedule(&sched_engine->tasklet);

spin_unlock_irqrestore(&sched_engine->lock, flags);
}
--
2.28.0