[PATCH v8 10/13] drm/i915: add infrastructure to hold off preemption on a request

[Lionel Landwerlin <lionel.g.landwerlin@intel.com>]

We want to set this flag in the next commit on requests containing
perf queries so that the result of the perf query can just be a delta
of global counters, rather than doing post processing of the OA
buffer.

Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
---
 drivers/gpu/drm/i915/gt/intel_lrc.c         |  7 ++++++-
 drivers/gpu/drm/i915/i915_priolist_types.h  |  7 +++++++
 drivers/gpu/drm/i915/i915_request.c         |  4 ++--
 drivers/gpu/drm/i915/i915_request.h         | 14 +++++++++++++-
 drivers/gpu/drm/i915/intel_guc_submission.c | 10 +++++++++-
 drivers/gpu/drm/i915/intel_pm.c             |  5 +++--
 6 files changed, 40 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
index 30782af8f4bc..6c35d33f9647 100644
--- a/drivers/gpu/drm/i915/gt/intel_lrc.c
+++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
@@ -256,7 +256,12 @@ static inline int rq_prio(const struct i915_request *rq)
 
 static int effective_prio(const struct i915_request *rq)
 {
-	int prio = rq_prio(rq);
+	int prio;
+
+	if (i915_request_has_perf(rq))
+		prio = I915_USER_PRIORITY(I915_PRIORITY_PERF);
+	else
+		prio = rq_prio(rq);
 
 	/*
 	 * On unwinding the active request, we give it a priority bump
diff --git a/drivers/gpu/drm/i915/i915_priolist_types.h b/drivers/gpu/drm/i915/i915_priolist_types.h
index 49709de69875..bb9d1e1fb94a 100644
--- a/drivers/gpu/drm/i915/i915_priolist_types.h
+++ b/drivers/gpu/drm/i915/i915_priolist_types.h
@@ -17,6 +17,13 @@ enum {
 	I915_PRIORITY_NORMAL = I915_CONTEXT_DEFAULT_PRIORITY,
 	I915_PRIORITY_MAX = I915_CONTEXT_MAX_USER_PRIORITY + 1,
 
+	/* Requests containing performance queries must not be preempted by
+	 * another context. They get scheduled with their default priority and
+	 * once they reach the execlist ports we bump them to
+	 * I915_PRIORITY_PERF so that they stick to the HW until they finish.
+	 */
+	I915_PRIORITY_PERF,
+
 	I915_PRIORITY_INVALID = INT_MIN
 };
 
diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
index 5ff87c4a0cd5..222c9c56e9de 100644
--- a/drivers/gpu/drm/i915/i915_request.c
+++ b/drivers/gpu/drm/i915/i915_request.c
@@ -292,7 +292,7 @@ static bool i915_request_retire(struct i915_request *rq)
 		dma_fence_signal_locked(&rq->fence);
 	if (test_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT, &rq->fence.flags))
 		i915_request_cancel_breadcrumb(rq);
-	if (rq->waitboost) {
+	if (i915_request_has_waitboost(rq)) {
 		GEM_BUG_ON(!atomic_read(&rq->i915->gt_pm.rps.num_waiters));
 		atomic_dec(&rq->i915->gt_pm.rps.num_waiters);
 	}
@@ -684,7 +684,7 @@ __i915_request_create(struct intel_context *ce, gfp_t gfp)
 	rq->file_priv = NULL;
 	rq->batch = NULL;
 	rq->capture_list = NULL;
-	rq->waitboost = false;
+	rq->flags = 0;
 	rq->execution_mask = ALL_ENGINES;
 
 	INIT_LIST_HEAD(&rq->active_list);
diff --git a/drivers/gpu/drm/i915/i915_request.h b/drivers/gpu/drm/i915/i915_request.h
index b58ceef92e20..26c46cdc67fe 100644
--- a/drivers/gpu/drm/i915/i915_request.h
+++ b/drivers/gpu/drm/i915/i915_request.h
@@ -216,7 +216,9 @@ struct i915_request {
 	/** Time at which this request was emitted, in jiffies. */
 	unsigned long emitted_jiffies;
 
-	bool waitboost;
+#define I915_REQUEST_WAITBOOST BIT(0)
+#define I915_REQUEST_NOPREEMPT BIT(1)
+	u32 flags;
 
 	/** timeline->request entry for this request */
 	struct list_head link;
@@ -430,6 +432,16 @@ static inline void i915_request_mark_complete(struct i915_request *rq)
 	rq->hwsp_seqno = (u32 *)&rq->fence.seqno; /* decouple from HWSP */
 }
 
+static inline bool i915_request_has_waitboost(const struct i915_request *rq)
+{
+	return rq->flags & I915_REQUEST_WAITBOOST;
+}
+
+static inline bool i915_request_has_perf(const struct i915_request *rq)
+{
+	return rq->flags & I915_REQUEST_NOPREEMPT;
+}
+
 bool i915_retire_requests(struct drm_i915_private *i915);
 
 #endif /* I915_REQUEST_H */
diff --git a/drivers/gpu/drm/i915/intel_guc_submission.c b/drivers/gpu/drm/i915/intel_guc_submission.c
index 12c22359fdac..48e7ae3d67a2 100644
--- a/drivers/gpu/drm/i915/intel_guc_submission.c
+++ b/drivers/gpu/drm/i915/intel_guc_submission.c
@@ -707,6 +707,14 @@ static inline int rq_prio(const struct i915_request *rq)
 	return rq->sched.attr.priority | __NO_PREEMPTION;
 }
 
+static inline int effective_prio(const struct i915_request *rq)
+{
+	if (i915_request_has_perf(rq))
+		return I915_USER_PRIORITY(I915_PRIORITY_PERF) | __NO_PREEMPTION;
+
+	return rq_prio(rq);
+}
+
 static struct i915_request *schedule_in(struct i915_request *rq, int idx)
 {
 	trace_i915_request_in(rq, idx);
@@ -747,7 +755,7 @@ static void __guc_dequeue(struct intel_engine_cs *engine)
 				&engine->i915->guc.preempt_work[engine->id];
 			int prio = execlists->queue_priority_hint;
 
-			if (i915_scheduler_need_preempt(prio, rq_prio(last))) {
+			if (i915_scheduler_need_preempt(prio, effective_prio(last))) {
 				intel_write_status_page(engine,
 							I915_GEM_HWS_PREEMPT,
 							GUC_PREEMPT_INPROGRESS);
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 87244d8215a7..0cecea228546 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -6876,9 +6876,10 @@ void gen6_rps_boost(struct i915_request *rq)
 	/* Serializes with i915_request_retire() */
 	boost = false;
 	spin_lock_irqsave(&rq->lock, flags);
-	if (!rq->waitboost && !dma_fence_is_signaled_locked(&rq->fence)) {
+	if (!i915_request_has_waitboost(rq) &&
+	    !dma_fence_is_signaled_locked(&rq->fence)) {
 		boost = !atomic_fetch_inc(&rps->num_waiters);
-		rq->waitboost = true;
+		rq->flags |= I915_REQUEST_WAITBOOST;
 	}
 	spin_unlock_irqrestore(&rq->lock, flags);
 	if (!boost)
-- 
2.22.0

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