From: Chris Wilson Date: Thu, 24 Dec 2020 13:55:41 +0000 (+0000) Subject: drm/i915/gt: Shrink the critical section for irq signaling X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=66e40750d2410bde862157cca6768a684984fb28;p=linux.git 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: Chris Wilson Reviewed-by: Matthew Brost Link: https://patchwork.freedesktop.org/patch/msgid/20201224135544.1713-6-chris@chris-wilson.co.uk --- diff --git a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c index 8f7c8595ba08c..2eabb9ab5d47c 100644 --- a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c +++ b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c @@ -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) { diff --git a/drivers/gpu/drm/i915/gt/intel_breadcrumbs_types.h b/drivers/gpu/drm/i915/gt/intel_breadcrumbs_types.h index d85a6f74fb872..3a084ce8ff5e1 100644 --- a/drivers/gpu/drm/i915/gt/intel_breadcrumbs_types.h +++ b/drivers/gpu/drm/i915/gt/intel_breadcrumbs_types.h @@ -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 */ diff --git a/drivers/gpu/drm/i915/gt/intel_execlists_submission.c b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c index 1f6e9fe5bcc0f..ba8229c0c75aa 100644 --- a/drivers/gpu/drm/i915/gt/intel_execlists_submission.c +++ b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c @@ -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))