[Intel-gfx] [RFC 05/10] drm/i915: Track runtime spent in unreachable intel_contexts

[Tvrtko Ursulin]

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

As contexts are abandoned we want to remember how much GPU time they used
(per class) so later we can used it for smarter purposes.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
---
 drivers/gpu/drm/i915/gem/i915_gem_context.c       | 13 ++++++++++++-
 drivers/gpu/drm/i915/gem/i915_gem_context_types.h |  5 +++++
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c
index c49cfec6d616..c521155a6474 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
@@ -257,7 +257,19 @@ static void free_engines_rcu(struct rcu_head *rcu)
 {
 	struct i915_gem_engines *engines =
 		container_of(rcu, struct i915_gem_engines, rcu);
+	struct i915_gem_context *ctx = engines->ctx;
+	struct i915_gem_engines_iter it;
+	struct intel_context *ce;
+
+	/* Transfer accumulated runtime to the parent GEM context. */
+	for_each_gem_engine(ce, engines, it) {
+		unsigned int class = ce->engine->uabi_class;
 
+		GEM_BUG_ON(class >= ARRAY_SIZE(ctx->past_runtime));
+		atomic64_add(ce->runtime.total, &ctx->past_runtime[class]);
+	}
+
+	i915_gem_context_put(ctx);
 	i915_sw_fence_fini(&engines->fence);
 	free_engines(engines);
 }
@@ -540,7 +552,6 @@ static int engines_notify(struct i915_sw_fence *fence,
 			list_del(&engines->link);
 			spin_unlock_irqrestore(&ctx->stale.lock, flags);
 		}
-		i915_gem_context_put(engines->ctx);
 		break;
 
 	case FENCE_FREE:
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context_types.h b/drivers/gpu/drm/i915/gem/i915_gem_context_types.h
index b0e03380c690..f0d7441aafc8 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_context_types.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_context_types.h
@@ -177,6 +177,11 @@ struct i915_gem_context {
 		spinlock_t lock;
 		struct list_head engines;
 	} stale;
+
+	/**
+	 * @past_runtime: Accumulation of freed intel_context pphwsp runtimes.
+	 */
+	atomic64_t past_runtime[MAX_ENGINE_CLASS + 1];
 };
 
 #endif /* __I915_GEM_CONTEXT_TYPES_H__ */
-- 
2.20.1