Re: [PATCH 25/51] drm/i915: Move active request tracking to a vfunc

[John Harrison <john.c.harrison@intel.com>]

On 7/16/2021 13:16, Matthew Brost wrote:
> Move active request tracking to a backend vfunc rather than assuming all
> backends want to do this in the maner. In the case execlists /
maner -> manner.
In the case *of* execlists

With those fixed...
Reviewed-by: John Harrison <John.C.Harrison@Intel.com>


> ring submission the tracking is on the physical engine while with GuC
> submission it is on the context.
>
> Signed-off-by: Matthew Brost <matthew.brost@intel.com>
> ---
>   drivers/gpu/drm/i915/gt/intel_context.c       |  3 ++
>   drivers/gpu/drm/i915/gt/intel_context_types.h |  7 ++++
>   drivers/gpu/drm/i915/gt/intel_engine_types.h  |  6 +++
>   .../drm/i915/gt/intel_execlists_submission.c  | 40 ++++++++++++++++++
>   .../gpu/drm/i915/gt/intel_ring_submission.c   | 22 ++++++++++
>   drivers/gpu/drm/i915/gt/mock_engine.c         | 30 ++++++++++++++
>   .../gpu/drm/i915/gt/uc/intel_guc_submission.c | 33 +++++++++++++++
>   drivers/gpu/drm/i915/i915_request.c           | 41 ++-----------------
>   drivers/gpu/drm/i915/i915_request.h           |  2 +
>   9 files changed, 147 insertions(+), 37 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/intel_context.c b/drivers/gpu/drm/i915/gt/intel_context.c
> index 251ff7eea22d..bfb05d8697d1 100644
> --- a/drivers/gpu/drm/i915/gt/intel_context.c
> +++ b/drivers/gpu/drm/i915/gt/intel_context.c
> @@ -393,6 +393,9 @@ intel_context_init(struct intel_context *ce, struct intel_engine_cs *engine)
>   	spin_lock_init(&ce->guc_state.lock);
>   	INIT_LIST_HEAD(&ce->guc_state.fences);
>   
> +	spin_lock_init(&ce->guc_active.lock);
> +	INIT_LIST_HEAD(&ce->guc_active.requests);
> +
>   	ce->guc_id = GUC_INVALID_LRC_ID;
>   	INIT_LIST_HEAD(&ce->guc_id_link);
>   
> diff --git a/drivers/gpu/drm/i915/gt/intel_context_types.h b/drivers/gpu/drm/i915/gt/intel_context_types.h
> index 542c98418771..035108c10b2c 100644
> --- a/drivers/gpu/drm/i915/gt/intel_context_types.h
> +++ b/drivers/gpu/drm/i915/gt/intel_context_types.h
> @@ -162,6 +162,13 @@ struct intel_context {
>   		struct list_head fences;
>   	} guc_state;
>   
> +	struct {
> +		/** lock: protects everything in guc_active */
> +		spinlock_t lock;
> +		/** requests: active requests on this context */
> +		struct list_head requests;
> +	} guc_active;
> +
>   	/* GuC scheduling state flags that do not require a lock. */
>   	atomic_t guc_sched_state_no_lock;
>   
> diff --git a/drivers/gpu/drm/i915/gt/intel_engine_types.h b/drivers/gpu/drm/i915/gt/intel_engine_types.h
> index 03a81e8d87f4..950fc73ed6af 100644
> --- a/drivers/gpu/drm/i915/gt/intel_engine_types.h
> +++ b/drivers/gpu/drm/i915/gt/intel_engine_types.h
> @@ -420,6 +420,12 @@ struct intel_engine_cs {
>   
>   	void		(*release)(struct intel_engine_cs *engine);
>   
> +	/*
> +	 * Add / remove request from engine active tracking
> +	 */
> +	void		(*add_active_request)(struct i915_request *rq);
> +	void		(*remove_active_request)(struct i915_request *rq);
> +
>   	struct intel_engine_execlists execlists;
>   
>   	/*
> diff --git a/drivers/gpu/drm/i915/gt/intel_execlists_submission.c b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c
> index abe48421fd7a..f9b5f54a5abe 100644
> --- a/drivers/gpu/drm/i915/gt/intel_execlists_submission.c
> +++ b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c
> @@ -3106,6 +3106,42 @@ static void execlists_park(struct intel_engine_cs *engine)
>   	cancel_timer(&engine->execlists.preempt);
>   }
>   
> +static void add_to_engine(struct i915_request *rq)
> +{
> +	lockdep_assert_held(&rq->engine->sched_engine->lock);
> +	list_move_tail(&rq->sched.link, &rq->engine->sched_engine->requests);
> +}
> +
> +static void remove_from_engine(struct i915_request *rq)
> +{
> +	struct intel_engine_cs *engine, *locked;
> +
> +	/*
> +	 * Virtual engines complicate acquiring the engine timeline lock,
> +	 * as their rq->engine pointer is not stable until under that
> +	 * engine lock. The simple ploy we use is to take the lock then
> +	 * check that the rq still belongs to the newly locked engine.
> +	 */
> +	locked = READ_ONCE(rq->engine);
> +	spin_lock_irq(&locked->sched_engine->lock);
> +	while (unlikely(locked != (engine = READ_ONCE(rq->engine)))) {
> +		spin_unlock(&locked->sched_engine->lock);
> +		spin_lock(&engine->sched_engine->lock);
> +		locked = engine;
> +	}
> +	list_del_init(&rq->sched.link);
> +
> +	clear_bit(I915_FENCE_FLAG_PQUEUE, &rq->fence.flags);
> +	clear_bit(I915_FENCE_FLAG_HOLD, &rq->fence.flags);
> +
> +	/* Prevent further __await_execution() registering a cb, then flush */
> +	set_bit(I915_FENCE_FLAG_ACTIVE, &rq->fence.flags);
> +
> +	spin_unlock_irq(&locked->sched_engine->lock);
> +
> +	i915_request_notify_execute_cb_imm(rq);
> +}
> +
>   static bool can_preempt(struct intel_engine_cs *engine)
>   {
>   	if (GRAPHICS_VER(engine->i915) > 8)
> @@ -3206,6 +3242,8 @@ logical_ring_default_vfuncs(struct intel_engine_cs *engine)
>   	engine->cops = &execlists_context_ops;
>   	engine->request_alloc = execlists_request_alloc;
>   	engine->bump_serial = execlist_bump_serial;
> +	engine->add_active_request = add_to_engine;
> +	engine->remove_active_request = remove_from_engine;
>   
>   	engine->reset.prepare = execlists_reset_prepare;
>   	engine->reset.rewind = execlists_reset_rewind;
> @@ -3797,6 +3835,8 @@ execlists_create_virtual(struct intel_engine_cs **siblings, unsigned int count)
>   			 "v%dx%d", ve->base.class, count);
>   		ve->base.context_size = sibling->context_size;
>   
> +		ve->base.add_active_request = sibling->add_active_request;
> +		ve->base.remove_active_request = sibling->remove_active_request;
>   		ve->base.emit_bb_start = sibling->emit_bb_start;
>   		ve->base.emit_flush = sibling->emit_flush;
>   		ve->base.emit_init_breadcrumb = sibling->emit_init_breadcrumb;
> diff --git a/drivers/gpu/drm/i915/gt/intel_ring_submission.c b/drivers/gpu/drm/i915/gt/intel_ring_submission.c
> index 61469c631057..3b1471c50d40 100644
> --- a/drivers/gpu/drm/i915/gt/intel_ring_submission.c
> +++ b/drivers/gpu/drm/i915/gt/intel_ring_submission.c
> @@ -1052,6 +1052,25 @@ static void ring_bump_serial(struct intel_engine_cs *engine)
>   	engine->serial++;
>   }
>   
> +static void add_to_engine(struct i915_request *rq)
> +{
> +	lockdep_assert_held(&rq->engine->sched_engine->lock);
> +	list_move_tail(&rq->sched.link, &rq->engine->sched_engine->requests);
> +}
> +
> +static void remove_from_engine(struct i915_request *rq)
> +{
> +	spin_lock_irq(&rq->engine->sched_engine->lock);
> +	list_del_init(&rq->sched.link);
> +
> +	/* Prevent further __await_execution() registering a cb, then flush */
> +	set_bit(I915_FENCE_FLAG_ACTIVE, &rq->fence.flags);
> +
> +	spin_unlock_irq(&rq->engine->sched_engine->lock);
> +
> +	i915_request_notify_execute_cb_imm(rq);
> +}
> +
>   static void setup_common(struct intel_engine_cs *engine)
>   {
>   	struct drm_i915_private *i915 = engine->i915;
> @@ -1069,6 +1088,9 @@ static void setup_common(struct intel_engine_cs *engine)
>   	engine->reset.cancel = reset_cancel;
>   	engine->reset.finish = reset_finish;
>   
> +	engine->add_active_request = add_to_engine;
> +	engine->remove_active_request = remove_from_engine;
> +
>   	engine->cops = &ring_context_ops;
>   	engine->request_alloc = ring_request_alloc;
>   	engine->bump_serial = ring_bump_serial;
> diff --git a/drivers/gpu/drm/i915/gt/mock_engine.c b/drivers/gpu/drm/i915/gt/mock_engine.c
> index fc5a65ab1937..5f86ff79c98c 100644
> --- a/drivers/gpu/drm/i915/gt/mock_engine.c
> +++ b/drivers/gpu/drm/i915/gt/mock_engine.c
> @@ -235,6 +235,34 @@ static void mock_submit_request(struct i915_request *request)
>   	spin_unlock_irqrestore(&engine->hw_lock, flags);
>   }
>   
> +static void mock_add_to_engine(struct i915_request *rq)
> +{
> +	lockdep_assert_held(&rq->engine->sched_engine->lock);
> +	list_move_tail(&rq->sched.link, &rq->engine->sched_engine->requests);
> +}
> +
> +static void mock_remove_from_engine(struct i915_request *rq)
> +{
> +	struct intel_engine_cs *engine, *locked;
> +
> +	/*
> +	 * Virtual engines complicate acquiring the engine timeline lock,
> +	 * as their rq->engine pointer is not stable until under that
> +	 * engine lock. The simple ploy we use is to take the lock then
> +	 * check that the rq still belongs to the newly locked engine.
> +	 */
> +
> +	locked = READ_ONCE(rq->engine);
> +	spin_lock_irq(&locked->sched_engine->lock);
> +	while (unlikely(locked != (engine = READ_ONCE(rq->engine)))) {
> +		spin_unlock(&locked->sched_engine->lock);
> +		spin_lock(&engine->sched_engine->lock);
> +		locked = engine;
> +	}
> +	list_del_init(&rq->sched.link);
> +	spin_unlock_irq(&locked->sched_engine->lock);
> +}
> +
>   static void mock_reset_prepare(struct intel_engine_cs *engine)
>   {
>   }
> @@ -327,6 +355,8 @@ struct intel_engine_cs *mock_engine(struct drm_i915_private *i915,
>   	engine->base.emit_flush = mock_emit_flush;
>   	engine->base.emit_fini_breadcrumb = mock_emit_breadcrumb;
>   	engine->base.submit_request = mock_submit_request;
> +	engine->base.add_active_request = mock_add_to_engine;
> +	engine->base.remove_active_request = mock_remove_from_engine;
>   
>   	engine->base.reset.prepare = mock_reset_prepare;
>   	engine->base.reset.rewind = mock_reset_rewind;
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> index 9f28899ff17f..f8a6077fa3f9 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> @@ -1147,6 +1147,33 @@ static int guc_context_alloc(struct intel_context *ce)
>   	return lrc_alloc(ce, ce->engine);
>   }
>   
> +static void add_to_context(struct i915_request *rq)
> +{
> +	struct intel_context *ce = rq->context;
> +
> +	spin_lock(&ce->guc_active.lock);
> +	list_move_tail(&rq->sched.link, &ce->guc_active.requests);
> +	spin_unlock(&ce->guc_active.lock);
> +}
> +
> +static void remove_from_context(struct i915_request *rq)
> +{
> +	struct intel_context *ce = rq->context;
> +
> +	spin_lock_irq(&ce->guc_active.lock);
> +
> +	list_del_init(&rq->sched.link);
> +	clear_bit(I915_FENCE_FLAG_PQUEUE, &rq->fence.flags);
> +
> +	/* Prevent further __await_execution() registering a cb, then flush */
> +	set_bit(I915_FENCE_FLAG_ACTIVE, &rq->fence.flags);
> +
> +	spin_unlock_irq(&ce->guc_active.lock);
> +
> +	atomic_dec(&ce->guc_id_ref);
> +	i915_request_notify_execute_cb_imm(rq);
> +}
> +
>   static const struct intel_context_ops guc_context_ops = {
>   	.alloc = guc_context_alloc,
>   
> @@ -1567,6 +1594,8 @@ static void guc_default_vfuncs(struct intel_engine_cs *engine)
>   	engine->cops = &guc_context_ops;
>   	engine->request_alloc = guc_request_alloc;
>   	engine->bump_serial = guc_bump_serial;
> +	engine->add_active_request = add_to_context;
> +	engine->remove_active_request = remove_from_context;
>   
>   	engine->sched_engine->schedule = i915_schedule;
>   
> @@ -1931,6 +1960,10 @@ guc_create_virtual(struct intel_engine_cs **siblings, unsigned int count)
>   				 "v%dx%d", ve->base.class, count);
>   			ve->base.context_size = sibling->context_size;
>   
> +			ve->base.add_active_request =
> +				sibling->add_active_request;
> +			ve->base.remove_active_request =
> +				sibling->remove_active_request;
>   			ve->base.emit_bb_start = sibling->emit_bb_start;
>   			ve->base.emit_flush = sibling->emit_flush;
>   			ve->base.emit_init_breadcrumb =
> diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
> index b3c792d55321..4eba848b20e3 100644
> --- a/drivers/gpu/drm/i915/i915_request.c
> +++ b/drivers/gpu/drm/i915/i915_request.c
> @@ -182,7 +182,7 @@ static bool irq_work_imm(struct irq_work *wrk)
>   	return false;
>   }
>   
> -static void __notify_execute_cb_imm(struct i915_request *rq)
> +void i915_request_notify_execute_cb_imm(struct i915_request *rq)
>   {
>   	__notify_execute_cb(rq, irq_work_imm);
>   }
> @@ -256,37 +256,6 @@ i915_request_active_engine(struct i915_request *rq,
>   	return ret;
>   }
>   
> -
> -static void remove_from_engine(struct i915_request *rq)
> -{
> -	struct intel_engine_cs *engine, *locked;
> -
> -	/*
> -	 * Virtual engines complicate acquiring the engine timeline lock,
> -	 * as their rq->engine pointer is not stable until under that
> -	 * engine lock. The simple ploy we use is to take the lock then
> -	 * check that the rq still belongs to the newly locked engine.
> -	 */
> -	locked = READ_ONCE(rq->engine);
> -	spin_lock_irq(&locked->sched_engine->lock);
> -	while (unlikely(locked != (engine = READ_ONCE(rq->engine)))) {
> -		spin_unlock(&locked->sched_engine->lock);
> -		spin_lock(&engine->sched_engine->lock);
> -		locked = engine;
> -	}
> -	list_del_init(&rq->sched.link);
> -
> -	clear_bit(I915_FENCE_FLAG_PQUEUE, &rq->fence.flags);
> -	clear_bit(I915_FENCE_FLAG_HOLD, &rq->fence.flags);
> -
> -	/* Prevent further __await_execution() registering a cb, then flush */
> -	set_bit(I915_FENCE_FLAG_ACTIVE, &rq->fence.flags);
> -
> -	spin_unlock_irq(&locked->sched_engine->lock);
> -
> -	__notify_execute_cb_imm(rq);
> -}
> -
>   static void __rq_init_watchdog(struct i915_request *rq)
>   {
>   	rq->watchdog.timer.function = NULL;
> @@ -383,9 +352,7 @@ bool i915_request_retire(struct i915_request *rq)
>   	 * after removing the breadcrumb and signaling it, so that we do not
>   	 * inadvertently attach the breadcrumb to a completed request.
>   	 */
> -	if (!list_empty(&rq->sched.link))
> -		remove_from_engine(rq);
> -	atomic_dec(&rq->context->guc_id_ref);
> +	rq->engine->remove_active_request(rq);
>   	GEM_BUG_ON(!llist_empty(&rq->execute_cb));
>   
>   	__list_del_entry(&rq->link); /* poison neither prev/next (RCU walks) */
> @@ -516,7 +483,7 @@ __await_execution(struct i915_request *rq,
>   	if (llist_add(&cb->work.node.llist, &signal->execute_cb)) {
>   		if (i915_request_is_active(signal) ||
>   		    __request_in_flight(signal))
> -			__notify_execute_cb_imm(signal);
> +			i915_request_notify_execute_cb_imm(signal);
>   	}
>   
>   	return 0;
> @@ -653,7 +620,7 @@ bool __i915_request_submit(struct i915_request *request)
>   	result = true;
>   
>   	GEM_BUG_ON(test_bit(I915_FENCE_FLAG_ACTIVE, &request->fence.flags));
> -	list_move_tail(&request->sched.link, &engine->sched_engine->requests);
> +	engine->add_active_request(request);
>   active:
>   	clear_bit(I915_FENCE_FLAG_PQUEUE, &request->fence.flags);
>   	set_bit(I915_FENCE_FLAG_ACTIVE, &request->fence.flags);
> diff --git a/drivers/gpu/drm/i915/i915_request.h b/drivers/gpu/drm/i915/i915_request.h
> index 717e5b292046..128030f43bbf 100644
> --- a/drivers/gpu/drm/i915/i915_request.h
> +++ b/drivers/gpu/drm/i915/i915_request.h
> @@ -647,4 +647,6 @@ bool
>   i915_request_active_engine(struct i915_request *rq,
>   			   struct intel_engine_cs **active);
>   
> +void i915_request_notify_execute_cb_imm(struct i915_request *rq);
> +
>   #endif /* I915_REQUEST_H */