[Intel-gfx] [PATCH v2 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

Signed-off-by: Praveen Diwakar <praveen.diwakar at intel.com>
Signed-off-by: Yogesh Marathe <yogesh.marathe at intel.com>
Signed-off-by: Aravindan Muthukumar <aravindan.muthukumar at intel.com>
Signed-off-by: Kedar J Karanje <kedar.j.karanje at intel.com>
Signed-off-by: Ankit Navik <ankit.p.navik at intel.com>
Suggested-by: Tvrtko Ursulin <tvrtko.ursulin at linux.intel.com>
---
 drivers/gpu/drm/i915/i915_drv.c            | 1 +
 drivers/gpu/drm/i915/i915_drv.h            | 5 +++++
 drivers/gpu/drm/i915/i915_gem_context.c    | 1 +
 drivers/gpu/drm/i915/i915_gem_context.h    | 6 ++++++
 drivers/gpu/drm/i915/i915_gem_execbuffer.c | 5 +++++
 drivers/gpu/drm/i915/intel_lrc.c           | 6 ++++++
 6 files changed, 24 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index f8cfd16..d37c46e 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -903,6 +903,7 @@ static int i915_driver_init_early(struct drm_i915_private *dev_priv,
 	mutex_init(&dev_priv->av_mutex);
 	mutex_init(&dev_priv->wm.wm_mutex);
 	mutex_init(&dev_priv->pps_mutex);
+	mutex_init(&dev_priv->pred_mutex);
 
 	i915_memcpy_init_early(dev_priv);
 
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 4aca534..137ec33 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1609,6 +1609,11 @@ struct drm_i915_private {
 	 * controller on different i2c buses. */
 	struct mutex gmbus_mutex;
 
+	/** pred_mutex protects against councurrent usage of pending
+	 * request counter for multiple contexts
+	 */
+	struct mutex pred_mutex;
+
 	/**
 	 * Base address of the gmbus and gpio block.
 	 */
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..04e3ff7 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.h
+++ b/drivers/gpu/drm/i915/i915_gem_context.h
@@ -194,6 +194,12 @@ 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, this is
+	 * controlled via a mutex
+	 */
+	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_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index 3f0c612..8afa2a5 100644
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -2178,6 +2178,7 @@ i915_gem_do_execbuffer(struct drm_device *dev,
 		       struct drm_syncobj **fences)
 {
 	struct i915_execbuffer eb;
+	struct drm_i915_private *dev_priv = to_i915(dev);
 	struct dma_fence *in_fence = NULL;
 	struct sync_file *out_fence = NULL;
 	int out_fence_fd = -1;
@@ -2390,6 +2391,10 @@ i915_gem_do_execbuffer(struct drm_device *dev,
 	 */
 	eb.request->batch = eb.batch;
 
+	mutex_lock(&dev_priv->pred_mutex);
+	atomic_inc(&eb.ctx->req_cnt);
+	mutex_unlock(&dev_priv->pred_mutex);
+
 	trace_i915_request_queue(eb.request, eb.batch_flags);
 	err = eb_submit(&eb);
 err_request:
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 1744792..bcbb66b 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -728,6 +728,12 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
 			trace_i915_request_in(rq, port_index(port, execlists));
 			last = rq;
 			submit = true;
+
+			mutex_lock(&rq->i915->pred_mutex);
+			if (atomic_read(&rq->gem_context->req_cnt) > 0)
+				atomic_dec(&rq->gem_context->req_cnt);
+
+			mutex_unlock(&rq->i915->pred_mutex);
 		}
 
 		rb_erase_cached(&p->node, &execlists->queue);
-- 
2.7.4