[Intel-gfx] [RFC 03/13] drm/i915: Keep a count of requests submitted from userspace

[Tvrtko Ursulin]

From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>

Keep a count of requests submitted from userspace and not yet runnable due
unresolved dependencies.

v2: Rename and move under the container struct. (Chris Wilson)
v3: Rebase.
v4: Move decrement site to the backend to shrink the window of double-
    accounting as much as possible. (Chris Wilson)

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
---
 drivers/gpu/drm/i915/i915_request.c     | 3 +++
 drivers/gpu/drm/i915/intel_engine_cs.c  | 3 ++-
 drivers/gpu/drm/i915/intel_lrc.c        | 1 +
 drivers/gpu/drm/i915/intel_ringbuffer.h | 8 ++++++++
 4 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
index 689f838e849c..97a157f47a87 100644
--- a/drivers/gpu/drm/i915/i915_request.c
+++ b/drivers/gpu/drm/i915/i915_request.c
@@ -474,6 +474,7 @@ void i915_request_submit(struct i915_request *request)
 	spin_lock_irqsave(&engine->timeline.lock, flags);
 
 	engine->request_stats.runnable++;
+	atomic_dec(&engine->request_stats.queued);
 
 	__i915_request_submit(request);
 
@@ -1036,6 +1037,8 @@ void i915_request_add(struct i915_request *request)
 	}
 	request->emitted_jiffies = jiffies;
 
+	atomic_inc(&engine->request_stats.queued);
+
 	/*
 	 * Let the backend know a new request has arrived that may need
 	 * to adjust the existing execution schedule due to a high priority
diff --git a/drivers/gpu/drm/i915/intel_engine_cs.c b/drivers/gpu/drm/i915/intel_engine_cs.c
index f46ef765aed0..1b3f562246c9 100644
--- a/drivers/gpu/drm/i915/intel_engine_cs.c
+++ b/drivers/gpu/drm/i915/intel_engine_cs.c
@@ -1460,11 +1460,12 @@ void intel_engine_dump(struct intel_engine_cs *engine,
 	if (i915_terminally_wedged(&engine->i915->gpu_error))
 		drm_printf(m, "*** WEDGED ***\n");
 
-	drm_printf(m, "\tcurrent seqno %x, last %x, hangcheck %x [%d ms], runnable %u\n",
+	drm_printf(m, "\tcurrent seqno %x, last %x, hangcheck %x [%d ms], queued %u, runnable %u\n",
 		   intel_engine_get_seqno(engine),
 		   intel_engine_last_submit(engine),
 		   engine->hangcheck.seqno,
 		   jiffies_to_msecs(jiffies - engine->hangcheck.action_timestamp),
+		   atomic_read(&engine->request_stats.queued),
 		   engine->request_stats.runnable);
 	drm_printf(m, "\tReset count: %d (global %d)\n",
 		   i915_reset_engine_count(error, engine),
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index f0c2673fce49..3e8b16ab1b33 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -1024,6 +1024,7 @@ static void queue_request(struct intel_engine_cs *engine,
 {
 	list_add_tail(&node->link, i915_sched_lookup_priolist(engine, prio));
 	engine->request_stats.runnable++;
+	atomic_dec(&engine->request_stats.queued);
 }
 
 static void __submit_queue_imm(struct intel_engine_cs *engine)
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
index 07491b6c7796..dc11ed10bac4 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -381,6 +381,14 @@ struct intel_engine_cs {
 	void *pinned_default_state;
 
 	struct {
+		/**
+		 * @queued: Number of submitted requests with dependencies.
+		 *
+		 * Count of requests waiting for dependencies before they can be
+		 * submitted to the backend.
+		 */
+		atomic_t queued;
+
 		/**
 		 * @runnable: Number of runnable requests sent to the backend.
 		 *
-- 
2.17.1