Commit 66e40750 authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915/gt: Shrink the critical section for irq signaling 



Let's only wait for the list iterator when decoupling the virtual
breadcrumb, as the signaling of all the requests may take a long time,
during which we do not want to keep the tasklet spinning.

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: default avatarMatthew Brost <matthew.brost@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201224135544.1713-6-chris@chris-wilson.co.uk
parent bab0557c

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

+2 −0
Original line number Diff line number Diff line
@@ -234,6 +234,7 @@ static void signal_irq_work(struct irq_work *work) 
		intel_breadcrumbs_disarm_irq(b);



	rcu_read_lock();

	atomic_inc(&b->signaler_active);

	list_for_each_entry_rcu(ce, &b->signalers, signal_link) {

		struct i915_request *rq;
@@ -269,6 +270,7 @@ static void signal_irq_work(struct irq_work *work) 
			}

		}

	}

	atomic_dec(&b->signaler_active);

	rcu_read_unlock();



	llist_for_each_safe(signal, sn, signal) {

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

+1 −0
Original line number Diff line number Diff line
@@ -34,6 +34,7 @@ struct intel_breadcrumbs { 
	spinlock_t signalers_lock; /* protects the list of signalers */

	struct list_head signalers;

	struct llist_head signaled_requests;

	atomic_t signaler_active;



	spinlock_t irq_lock; /* protects the interrupt from hardirq context */

	struct irq_work irq_work; /* for use from inside irq_lock */

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

+2 −1
Original line number Diff line number Diff line
@@ -594,7 +594,8 @@ static void kick_siblings(struct i915_request *rq, struct intel_context *ce) 
		 * ce->signal_link.

		 */

		i915_request_cancel_breadcrumb(rq);

		irq_work_sync(&engine->breadcrumbs->irq_work);

		while (atomic_read(&engine->breadcrumbs->signaler_active))

			cpu_relax();

	}



	if (READ_ONCE(ve->request))