drm/i915: make context status notifier head be per engine

GVTg has introduced the context status notifier to schedule the GVTg
workload. At that time, the notifier is bound to GVTg context only,
so GVTg is not aware of host workloads.

Now we are going to improve GVTg's guest workload scheduler policy,
and add Guc emulation support for new Gen graphics. Both these two
features require acknowledgment for all contexts running on hardware.
(But will not alter host workload.) So here try to make some change.

The change is simple:
  1. Move the context status notifier head from i915_gem_context to
     intel_engine_cs. Which means there is a notifier head per engine
     instead of per context. Execlist driver still call notifier for
     each context sched-in/out events of current engine.
  2. At GVTg side, it binds a notifier_block for each physical engine
     at GVTg initialization period. Then GVTg can hear all context
     status events.

In this patch, GVTg do nothing for host context event, but later
will add a function there. But in any case, the notifier callback is
a noop if this is no active vGPU.

Since intel_gvt_init() is called at early initialization stage and
require the status notifier head has been initiated, I initiate it in
intel_engine_setup().

v2: remove a redundant newline. (chris)

Fixes: 3c7ba6359d70 ("drm/i915: Introduce execlist context status change notification")
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=100232
Signed-off-by: Changbin Du <changbin.du@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Zhi Wang <zhi.a.wang@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/20170313024711.28591-1-changbin.du@intel.com
Acked-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 19 insertions, 26 deletions

diff --git a/drivers/gpu/drm/i915/gvt/scheduler.c b/drivers/gpu/drm/i915/gvt/scheduler.c
index d6b6d0efdd1a..b14c5c2109d4 100644
--- a/drivers/gpu/drm/i915/gvt/scheduler.c
+++ b/drivers/gpu/drm/i915/gvt/scheduler.c
@@ -130,12 +130,10 @@ static int populate_shadow_context(struct intel_vgpu_workload *workload)
 static int shadow_context_status_change(struct notifier_block *nb,
 		unsigned long action, void *data)
 {
-	struct intel_vgpu *vgpu = container_of(nb,
-			struct intel_vgpu, shadow_ctx_notifier_block);
-	struct drm_i915_gem_request *req =
-		(struct drm_i915_gem_request *)data;
-	struct intel_gvt_workload_scheduler *scheduler =
-		&vgpu->gvt->scheduler;
+	struct drm_i915_gem_request *req = (struct drm_i915_gem_request *)data;
+	struct intel_gvt *gvt = container_of(nb, struct intel_gvt,
+				shadow_ctx_notifier_block[req->engine->id]);
+	struct intel_gvt_workload_scheduler *scheduler = &gvt->scheduler;
 	struct intel_vgpu_workload *workload =
 		scheduler->current_workload[req->engine->id];
 
@@ -493,15 +491,16 @@ void intel_gvt_wait_vgpu_idle(struct intel_vgpu *vgpu)
 void intel_gvt_clean_workload_scheduler(struct intel_gvt *gvt)
 {
 	struct intel_gvt_workload_scheduler *scheduler = &gvt->scheduler;
-	int i;
+	struct intel_engine_cs *engine;
+	enum intel_engine_id i;
 
 	gvt_dbg_core("clean workload scheduler\n");
 
-	for (i = 0; i < I915_NUM_ENGINES; i++) {
-		if (scheduler->thread[i]) {
-			kthread_stop(scheduler->thread[i]);
-			scheduler->thread[i] = NULL;
-		}
+	for_each_engine(engine, gvt->dev_priv, i) {
+		atomic_notifier_chain_unregister(
+					&engine->context_status_notifier,
+					&gvt->shadow_ctx_notifier_block[i]);
+		kthread_stop(scheduler->thread[i]);
 	}
 }
 
@@ -509,18 +508,15 @@ int intel_gvt_init_workload_scheduler(struct intel_gvt *gvt)
 {
 	struct intel_gvt_workload_scheduler *scheduler = &gvt->scheduler;
 	struct workload_thread_param *param = NULL;
+	struct intel_engine_cs *engine;
+	enum intel_engine_id i;
 	int ret;
-	int i;
 
 	gvt_dbg_core("init workload scheduler\n");
 
 	init_waitqueue_head(&scheduler->workload_complete_wq);
 
-	for (i = 0; i < I915_NUM_ENGINES; i++) {
-		/* check ring mask at init time */
-		if (!HAS_ENGINE(gvt->dev_priv, i))
-			continue;
-
+	for_each_engine(engine, gvt->dev_priv, i) {
 		init_waitqueue_head(&scheduler->waitq[i]);
 
 		param = kzalloc(sizeof(*param), GFP_KERNEL);
@@ -539,6 +535,11 @@ int intel_gvt_init_workload_scheduler(struct intel_gvt *gvt)
 			ret = PTR_ERR(scheduler->thread[i]);
 			goto err;
 		}
+
+		gvt->shadow_ctx_notifier_block[i].notifier_call =
+					shadow_context_status_change;
+		atomic_notifier_chain_register(&engine->context_status_notifier,
+					&gvt->shadow_ctx_notifier_block[i]);
 	}
 	return 0;
 err:
@@ -550,9 +551,6 @@ err:
 
 void intel_vgpu_clean_gvt_context(struct intel_vgpu *vgpu)
 {
-	atomic_notifier_chain_unregister(&vgpu->shadow_ctx->status_notifier,
-			&vgpu->shadow_ctx_notifier_block);
-
 	i915_gem_context_put_unlocked(vgpu->shadow_ctx);
 }
 
@@ -567,10 +565,5 @@ int intel_vgpu_init_gvt_context(struct intel_vgpu *vgpu)
 
 	vgpu->shadow_ctx->engine[RCS].initialised = true;
 
-	vgpu->shadow_ctx_notifier_block.notifier_call =
-		shadow_context_status_change;
-
-	atomic_notifier_chain_register(&vgpu->shadow_ctx->status_notifier,
-				       &vgpu->shadow_ctx_notifier_block);
 	return 0;
 }