[RFCv2,13/14] drm/i915: Support context single submission when GVT is active

Commit Message

Wang, Zhi A Feb. 18, 2016, 11:42 a.m. UTC

This patch introduces a new request picking logic to support the single-
submission context. As GVT context may comes from different guests, which
requires different configuration of render registers configuration. It
can't be combined in a dual ELSP submission combo.

We make this function as a context feature in context creation service.
Only GVT-g will create this kinds of GEM context currently, which only
allows to be single submitted.

Signed-off-by: Zhi Wang <[e-mail]>
---
 drivers/gpu/drm/i915/i915_drv.h  |  1 +
 drivers/gpu/drm/i915/intel_lrc.c | 42 +++++++++++++++++++++++++++++++++++++++-
 drivers/gpu/drm/i915/intel_lrc.h |  1 +
 3 files changed, 43 insertions(+), 1 deletion(-)

Comments

Tian, Kevin Feb. 24, 2016, 8:52 a.m. UTC | #1

> From: Wang, Zhi A
> Sent: Thursday, February 18, 2016 7:42 PM
> diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
> index 1c0366a..2a6d6fe 100644
> --- a/drivers/gpu/drm/i915/intel_lrc.c
> +++ b/drivers/gpu/drm/i915/intel_lrc.c
> @@ -479,6 +479,40 @@ static void execlists_i915_pick_requests(struct intel_engine_cs
> *ring,
>  	}
>  }
> 
> +static void execlists_gvt_pick_requests(struct intel_engine_cs *ring,
> +		struct drm_i915_gem_request **req0,
> +		struct drm_i915_gem_request **req1)

not read carefully, but if single submission itself has nothing tied to GVT,
better to make it generic since there may be other users in the future...

Thanks
Kevin

Patch

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 1f94df2..0850b35 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -890,6 +890,7 @@  struct intel_context {
 		bool need_status_change_notification;
 		struct atomic_notifier_head notifier_head;
 	} engine[I915_NUM_RINGS];
+	bool single_submission;
 	bool root_pointer_dirty;
 
 	struct list_head link;
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 1c0366a..2a6d6fe 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -479,6 +479,40 @@  static void execlists_i915_pick_requests(struct intel_engine_cs *ring,
 	}
 }
 
+static void execlists_gvt_pick_requests(struct intel_engine_cs *ring,
+		struct drm_i915_gem_request **req0,
+		struct drm_i915_gem_request **req1)
+{
+	struct drm_i915_gem_request *cursor, *tmp;
+
+	*req0 = *req1 = NULL;
+
+	/* Try to read in pairs */
+	list_for_each_entry_safe(cursor, tmp, &ring->execlist_queue,
+			execlist_link) {
+		if (!*req0) {
+			*req0 = cursor;
+			/* single submission */
+			if ((*req0)->ctx->single_submission)
+				break;
+		} else if ((*req0)->ctx == cursor->ctx) {
+			/*
+			 * Same ctx: ignore first request, as second request
+			 * will update tail past first request's workload
+			 */
+			cursor->elsp_submitted = (*req0)->elsp_submitted;
+			list_move_tail(&(*req0)->execlist_link,
+					&ring->execlist_retired_req_list);
+			*req0 = cursor;
+		} else {
+			/* single submission */
+			if (!cursor->ctx->single_submission)
+				*req1 = cursor;
+			break;
+		}
+	}
+}
+
 static void execlists_context_unqueue(struct intel_engine_cs *ring)
 {
 	struct drm_i915_gem_request *req0, *req1;
@@ -494,7 +528,10 @@  static void execlists_context_unqueue(struct intel_engine_cs *ring)
 	if (list_empty(&ring->execlist_queue))
 		return;
 
-	execlists_i915_pick_requests(ring, &req0, &req1);
+	if (!intel_gvt_active(ring->dev))
+		execlists_i915_pick_requests(ring, &req0, &req1);
+	else
+		execlists_gvt_pick_requests(ring, &req0, &req1);
 
 	if (IS_GEN8(ring->dev) || IS_GEN9(ring->dev)) {
 		/*
@@ -2629,6 +2666,9 @@  int __intel_lr_context_deferred_alloc(struct intel_context *ctx,
 			&ctx->engine[ring->id].notifier_head);
 	}
 
+	if (params->ctx_needs_single_submission)
+		ctx->single_submission = true;
+
 	return 0;
 
 error_ringbuf:
diff --git a/drivers/gpu/drm/i915/intel_lrc.h b/drivers/gpu/drm/i915/intel_lrc.h
index 15791d4..4873dd8 100644
--- a/drivers/gpu/drm/i915/intel_lrc.h
+++ b/drivers/gpu/drm/i915/intel_lrc.h
@@ -107,6 +107,7 @@  struct intel_lr_context_alloc_params {
 	u32 ringbuffer_size;
 	bool ctx_needs_init;
 	bool ctx_needs_status_change_notification;
+	bool ctx_needs_single_submission;
 };
 
 void intel_lr_context_free(struct intel_context *ctx);