[Intel-gfx] [PATCH v3 1/4] drm/i915: Get active pending request for given context

[Ankit Navik]

From: Praveen Diwakar <praveen.diwakar at intel.com>

This patch gives us the active pending request count which is yet
to be submitted to the GPU

V2:
 * Change 64-bit to atomic for request count. (Tvrtko Ursulin)

V3:
 * Remove mutex for request count.
 * Rebase.
 * Fixes hitting underflow for predictive request. (Tvrtko Ursulin)

Cc: Aravindan Muthukumar <aravindan.muthukumar at intel.com>
Cc: Kedar J Karanje <kedar.j.karanje at intel.com>
Cc: Yogesh Marathe <yogesh.marathe at intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin at linux.intel.com>
Signed-off-by: Praveen Diwakar <praveen.diwakar at intel.com>
Signed-off-by: Ankit Navik <ankit.p.navik at intel.com>
---
 drivers/gpu/drm/i915/i915_gem_context.c | 1 +
 drivers/gpu/drm/i915/i915_gem_context.h | 5 +++++
 drivers/gpu/drm/i915/i915_request.c     | 2 ++
 drivers/gpu/drm/i915/intel_lrc.c        | 2 ++
 4 files changed, 10 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
index b10770c..0bcbe32 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -387,6 +387,7 @@ i915_gem_create_context(struct drm_i915_private *dev_priv,
 	}
 
 	trace_i915_context_create(ctx);
+	atomic_set(&ctx->req_cnt, 0);
 
 	return ctx;
 }
diff --git a/drivers/gpu/drm/i915/i915_gem_context.h b/drivers/gpu/drm/i915/i915_gem_context.h
index b116e49..e824b15 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.h
+++ b/drivers/gpu/drm/i915/i915_gem_context.h
@@ -194,6 +194,11 @@ struct i915_gem_context {
 	 * context close.
 	 */
 	struct list_head handles_list;
+
+	/** req_cnt: tracks the pending commands, based on which we decide to
+	 * go for low/medium/high load configuration of the GPU.
+	 */
+	atomic_t req_cnt;
 };
 
 static inline bool i915_gem_context_is_closed(const struct i915_gem_context *ctx)
diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
index 5c2c93c..b90795a 100644
--- a/drivers/gpu/drm/i915/i915_request.c
+++ b/drivers/gpu/drm/i915/i915_request.c
@@ -1113,6 +1113,8 @@ void i915_request_add(struct i915_request *request)
 	}
 	request->emitted_jiffies = jiffies;
 
+	atomic_inc(&request->gem_context->req_cnt);
+
 	/*
 	 * 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_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 1744792..d33f5ac 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -1127,6 +1127,8 @@ static void execlists_submit_request(struct i915_request *request)
 	submit_queue(engine, rq_prio(request));
 
 	spin_unlock_irqrestore(&engine->timeline.lock, flags);
+
+	atomic_dec(&request->gem_context->req_cnt);
 }
 
 static struct i915_request *sched_to_request(struct i915_sched_node *node)
-- 
2.7.4