Commit 2854d866 authored by Chris Wilson's avatar Chris Wilson Committed by Joonas Lahtinen
Browse files

drm/i915/gt: Replace intel_engine_transfer_stale_breadcrumbs 



After staring at the breadcrumb enabling/cancellation and coming to the
conclusion that the cause of the mysterious stale breadcrumbs must the
act of submitting a completed requests, we can then redirect those
completed requests onto a dedicated signaled_list at the time of
construction and so eliminate intel_engine_transfer_stale_breadcrumbs().

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: default avatarTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200731154834.8378-2-chris@chris-wilson.co.uk


Signed-off-by: default avatarRodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: default avatarJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
parent c18636f7

drivers/gpu/drm/i915/gt/intel_breadcrumbs.c

+19 −31
Original line number Diff line number Diff line
@@ -142,16 +142,16 @@ static void add_retire(struct intel_breadcrumbs *b, struct intel_timeline *tl) 
	intel_engine_add_retire(engine, tl);

}



static void __signal_request(struct i915_request *rq, struct list_head *signals)

static bool __signal_request(struct i915_request *rq, struct list_head *signals)

{

	GEM_BUG_ON(!test_bit(I915_FENCE_FLAG_SIGNAL, &rq->fence.flags));

	clear_bit(I915_FENCE_FLAG_SIGNAL, &rq->fence.flags);



	if (!__dma_fence_signal(&rq->fence))

		return;

		return false;



	i915_request_get(rq);

	list_add_tail(&rq->signal_link, signals);

	return true;

}



static void signal_irq_work(struct irq_work *work)
@@ -278,32 +278,6 @@ void intel_engine_reset_breadcrumbs(struct intel_engine_cs *engine) 
	spin_unlock_irqrestore(&b->irq_lock, flags);

}



void intel_engine_transfer_stale_breadcrumbs(struct intel_engine_cs *engine,

					     struct intel_context *ce)

{

	struct intel_breadcrumbs *b = &engine->breadcrumbs;

	unsigned long flags;



	spin_lock_irqsave(&b->irq_lock, flags);

	if (!list_empty(&ce->signals)) {

		struct i915_request *rq, *next;



		/* Queue for executing the signal callbacks in the irq_work */

		list_for_each_entry_safe(rq, next, &ce->signals, signal_link) {

			GEM_BUG_ON(rq->engine != engine);

			GEM_BUG_ON(!__request_completed(rq));



			__signal_request(rq, &b->signaled_requests);

		}



		INIT_LIST_HEAD(&ce->signals);

		list_del_init(&ce->signal_link);



		irq_work_queue(&b->irq_work);

	}

	spin_unlock_irqrestore(&b->irq_lock, flags);

}



void intel_engine_fini_breadcrumbs(struct intel_engine_cs *engine)

{

}
@@ -317,6 +291,17 @@ static void insert_breadcrumb(struct i915_request *rq, 
	if (test_bit(I915_FENCE_FLAG_SIGNAL, &rq->fence.flags))

		return;



	/*

	 * If the request is already completed, we can transfer it

	 * straight onto a signaled list, and queue the irq worker for

	 * its signal completion.

	 */

	if (__request_completed(rq)) {

		if (__signal_request(rq, &b->signaled_requests))

			irq_work_queue(&b->irq_work);

		return;

	}



	__intel_breadcrumbs_arm_irq(b);



	/*
@@ -344,8 +329,11 @@ static void insert_breadcrumb(struct i915_request *rq, 
	if (pos == &ce->signals) /* catch transitions from empty list */

		list_move_tail(&ce->signal_link, &b->signalers);

	GEM_BUG_ON(!check_signal_order(ce, rq));



	set_bit(I915_FENCE_FLAG_SIGNAL, &rq->fence.flags);



	/* Check after attaching to irq, interrupt may have already fired. */

	if (__request_completed(rq))

		irq_work_queue(&b->irq_work);

}



bool i915_request_enable_breadcrumb(struct i915_request *rq)
@@ -401,7 +389,7 @@ bool i915_request_enable_breadcrumb(struct i915_request *rq) 


	spin_unlock(&b->irq_lock);



	return !__request_completed(rq);

	return true;

}



void i915_request_cancel_breadcrumb(struct i915_request *rq)

drivers/gpu/drm/i915/gt/intel_engine.h

+0 −3
Original line number Diff line number Diff line
@@ -237,9 +237,6 @@ intel_engine_signal_breadcrumbs(struct intel_engine_cs *engine) 
void intel_engine_reset_breadcrumbs(struct intel_engine_cs *engine);

void intel_engine_fini_breadcrumbs(struct intel_engine_cs *engine);



void intel_engine_transfer_stale_breadcrumbs(struct intel_engine_cs *engine,

					     struct intel_context *ce);



void intel_engine_print_breadcrumbs(struct intel_engine_cs *engine,

				    struct drm_printer *p);

drivers/gpu/drm/i915/gt/intel_lrc.c

+0 −15
Original line number Diff line number Diff line
@@ -1805,18 +1805,6 @@ static bool virtual_matches(const struct virtual_engine *ve, 
	return true;

}



static void virtual_xfer_breadcrumbs(struct virtual_engine *ve)

{

	/*

	 * All the outstanding signals on ve->siblings[0] must have

	 * been completed, just pending the interrupt handler. As those

	 * signals still refer to the old sibling (via rq->engine), we must

	 * transfer those to the old irq_worker to keep our locking

	 * consistent.

	 */

	intel_engine_transfer_stale_breadcrumbs(ve->siblings[0], &ve->context);

}



#define for_each_waiter(p__, rq__) \

	list_for_each_entry_lockless(p__, \

				     &(rq__)->sched.waiters_list, \
@@ -2267,9 +2255,6 @@ static void execlists_dequeue(struct intel_engine_cs *engine) 
					virtual_update_register_offsets(regs,

									engine);



				if (!list_empty(&ve->context.signals))

					virtual_xfer_breadcrumbs(ve);



				/*

				 * Move the bound engine to the top of the list

				 * for future execution. We then kick this

drivers/gpu/drm/i915/i915_request.c

+2 −3
Original line number Diff line number Diff line
@@ -569,9 +569,8 @@ xfer: 
	 */

	__notify_execute_cb(request);



	if (test_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT, &request->fence.flags) &&

	    !i915_request_enable_breadcrumb(request))

		intel_engine_signal_breadcrumbs(engine);

	if (test_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT, &request->fence.flags))

		i915_request_enable_breadcrumb(request);



	return result;

}

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