[PATCH 35/44] drm/i915: Track active engines within a context

[Chris Wilson]

For use in the next patch, if we track which engines have been used by
the HW, we can reduce the work required to flush our state off the HW to
those engines.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/i915_gem_context.c | 3 +++
 drivers/gpu/drm/i915/i915_gem_context.h | 4 ++++
 drivers/gpu/drm/i915/intel_lrc.c        | 2 ++
 drivers/gpu/drm/i915/intel_ringbuffer.c | 3 +++
 4 files changed, 12 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
index 117b0c139bd2..3ae1609a418a 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -210,6 +210,7 @@ static void i915_gem_context_free(struct i915_gem_context *ctx)
 
 	lockdep_assert_held(&ctx->i915->drm.struct_mutex);
 	GEM_BUG_ON(!i915_gem_context_is_closed(ctx));
+	GEM_BUG_ON(!list_empty(&ctx->active_engines));
 
 	release_hw_id(ctx);
 	i915_ppgtt_put(ctx->ppgtt);
@@ -337,6 +338,7 @@ intel_context_init(struct intel_context *ce,
 		   struct intel_engine_cs *engine)
 {
 	ce->gem_context = ctx;
+	ce->engine = engine;
 
 	INIT_LIST_HEAD(&ce->signal_link);
 	INIT_LIST_HEAD(&ce->signals);
@@ -364,6 +366,7 @@ __create_hw_context(struct drm_i915_private *dev_priv,
 	list_add_tail(&ctx->link, &dev_priv->contexts.list);
 	ctx->i915 = dev_priv;
 	ctx->sched.priority = I915_USER_PRIORITY(I915_PRIORITY_NORMAL);
+	INIT_LIST_HEAD(&ctx->active_engines);
 
 	for (n = 0; n < ARRAY_SIZE(ctx->__engine); n++)
 		intel_context_init(&ctx->__engine[n], ctx, dev_priv->engine[n]);
diff --git a/drivers/gpu/drm/i915/i915_gem_context.h b/drivers/gpu/drm/i915/i915_gem_context.h
index cd753b976a70..3d04ef0200a3 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.h
+++ b/drivers/gpu/drm/i915/i915_gem_context.h
@@ -151,6 +151,8 @@ struct i915_gem_context {
 	atomic_t hw_id_pin_count;
 	struct list_head hw_id_link;
 
+	struct list_head active_engines;
+
 	/**
 	 * @user_handle: userspace identifier
 	 *
@@ -164,7 +166,9 @@ struct i915_gem_context {
 	/** engine: per-engine logical HW state */
 	struct intel_context {
 		struct i915_gem_context *gem_context;
+		struct intel_engine_cs *engine;
 		struct intel_engine_cs *active;
+		struct list_head active_link;
 		struct list_head signal_link;
 		struct list_head signals;
 		struct i915_vma *state;
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index ddf77a035953..54f45f2fdf67 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -1273,6 +1273,7 @@ static void execlists_context_unpin(struct intel_context *ce)
 		GEM_BUG_ON(READ_ONCE(ce->active));
 	}
 
+	list_del(&ce->active_link);
 	i915_gem_context_unpin_hw_id(ce->gem_context);
 
 	intel_ring_unpin(ce->ring);
@@ -1364,6 +1365,7 @@ __execlists_context_pin(struct intel_engine_cs *engine,
 
 	__execlists_update_reg_state(engine, ce);
 
+	list_add(&ce->active_link, &ctx->active_engines);
 	ce->state->obj->pin_global++;
 	i915_gem_context_get(ctx);
 	return ce;
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 6403b711dd2d..48dfca8aefa8 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -1414,6 +1414,8 @@ static void __context_unpin(struct intel_context *ce)
 {
 	struct i915_vma *vma;
 
+	list_del(&ce->active_link);
+
 	vma = ce->state;
 	if (!vma)
 		return;
@@ -1526,6 +1528,7 @@ __ring_context_pin(struct intel_engine_cs *engine,
 	if (err)
 		goto err_unpin;
 
+	list_add(&ce->active_link, &ctx->active_engines);
 	i915_gem_context_get(ctx);
 
 	/* One ringbuffer to rule them all */
-- 
2.20.1