[PATCH 50/65] rps-double-boost-nospin

[Chris Wilson]

---
 drivers/gpu/drm/i915/i915_debugfs.c     |  3 +--
 drivers/gpu/drm/i915/i915_drv.h         |  2 +-
 drivers/gpu/drm/i915/i915_gem_request.c |  4 ++--
 drivers/gpu/drm/i915/i915_sysfs.c       |  2 +-
 drivers/gpu/drm/i915/intel_gt_pm.c      | 11 +++++++----
 drivers/gpu/drm/i915/intel_pm.c         |  1 -
 6 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index f5ec5cd8fee6..84ccaf8a852d 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -2154,8 +2154,7 @@ static int i915_rps_boost_info(struct seq_file *m, void *data)
 	seq_printf(m, "GPU busy? %s [%d requests]\n",
 		   yesno(dev_priv->gt.awake), dev_priv->gt.active_requests);
 	seq_printf(m, "CPU waiting? %d\n", count_irq_waiters(dev_priv));
-	seq_printf(m, "Boosts outstanding? %d\n",
-		   atomic_read(&rps->num_waiters));
+	seq_printf(m, "Boosts outstanding? %d\n", READ_ONCE(rps->num_waiters));
 	seq_printf(m, "Frequency requested %d\n",
 		   intel_gpu_freq(dev_priv, rps->cur_freq));
 	seq_printf(m, "  min hard:%d, soft:%d; max soft:%d, hard:%d\n",
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 5f6c19ecc159..9efb799609a1 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -929,7 +929,7 @@ struct intel_rps {
 	enum { LOW_POWER, BETWEEN, HIGH_POWER } power;
 
 	bool enabled;
-	atomic_t num_waiters;
+	unsigned int num_waiters;
 	atomic_t boosts;
 
 	/* manual wa residency calculations */
diff --git a/drivers/gpu/drm/i915/i915_gem_request.c b/drivers/gpu/drm/i915/i915_gem_request.c
index d53310bc13ab..6b9526b7ef76 100644
--- a/drivers/gpu/drm/i915/i915_gem_request.c
+++ b/drivers/gpu/drm/i915/i915_gem_request.c
@@ -441,12 +441,12 @@ static void i915_gem_request_retire(struct drm_i915_gem_request *request)
 	engine->last_retired_context = request->ctx;
 
 	spin_lock_irq(&request->lock);
-	if (request->waitboost)
-		atomic_dec(&request->i915->gt_pm.rps.num_waiters);
 	if (!test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &request->fence.flags))
 		dma_fence_signal_locked(&request->fence);
 	if (test_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT, &request->fence.flags))
 		intel_engine_cancel_signaling(request);
+	if (request->waitboost)
+		request->i915->gt_pm.rps.num_waiters--;
 	spin_unlock_irq(&request->lock);
 
 	i915_priotree_fini(request->i915, &request->priotree);
diff --git a/drivers/gpu/drm/i915/i915_sysfs.c b/drivers/gpu/drm/i915/i915_sysfs.c
index 3278e32d3d84..989480c0b576 100644
--- a/drivers/gpu/drm/i915/i915_sysfs.c
+++ b/drivers/gpu/drm/i915/i915_sysfs.c
@@ -321,7 +321,7 @@ static ssize_t gt_boost_freq_mhz_store(struct device *kdev,
 	mutex_lock(&rps->lock);
 	if (val != rps->boost_freq) {
 		rps->boost_freq = val;
-		boost = atomic_read(&rps->num_waiters);
+		boost = READ_ONCE(rps->num_waiters);
 	}
 	mutex_unlock(&rps->lock);
 	if (boost)
diff --git a/drivers/gpu/drm/i915/intel_gt_pm.c b/drivers/gpu/drm/i915/intel_gt_pm.c
index b254eb0699f5..428760f520d1 100644
--- a/drivers/gpu/drm/i915/intel_gt_pm.c
+++ b/drivers/gpu/drm/i915/intel_gt_pm.c
@@ -508,7 +508,7 @@ static void intel_rps_work(struct work_struct *work)
 	pm_iir = xchg(&rps->pm_iir, 0) & ~i915->pm_rps_events;
 	pm_iir |= vlv_wa_c0_ei(i915, pm_iir);
 
-	client_boost = atomic_read(&rps->num_waiters);
+	client_boost = READ_ONCE(rps->num_waiters);
 
 	mutex_lock(&rps->lock);
 
@@ -639,12 +639,15 @@ void gen6_rps_boost(struct drm_i915_gem_request *rq,
 	if (!rps->enabled)
 		return;
 
+	if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &rq->fence.flags))
+		return;
+
+	/* Serializes with i915_gem_request_retire() */
 	boost = false;
 	spin_lock_irqsave(&rq->lock, flags);
-	if (!rq->waitboost && !i915_gem_request_completed(rq)) {
-		atomic_inc(&rps->num_waiters);
+	if (!rq->waitboost && !dma_fence_is_signaled_locked(&rq->fence)) {
+		boost = !rps->num_waiters++;
 		rq->waitboost = true;
-		boost = true;
 	}
 	spin_unlock_irqrestore(&rq->lock, flags);
 	if (!boost)
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 456433539b1e..45050750c4bb 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -6812,7 +6812,6 @@ void intel_init_pm(struct drm_i915_private *dev_priv)
 void intel_pm_setup(struct drm_i915_private *dev_priv)
 {
 	mutex_init(&dev_priv->gt_pm.rps.lock);
-	atomic_set(&dev_priv->gt_pm.rps.num_waiters, 0);
 
 	dev_priv->runtime_pm.suspended = false;
 	atomic_set(&dev_priv->runtime_pm.wakeref_count, 0);
-- 
2.15.1