Chris Wilson <[email protected]> writes: > By taking advantage of the RCU protection of the task struct, we can find > the appropriate signaler under the spinlock and then release the spinlock > before waking the task and signaling the fence. > > Signed-off-by: Chris Wilson <[email protected]> > Cc: Mika Kuoppala <[email protected]>
Reviewed-by: Mika Kuoppala <[email protected]> > --- > drivers/gpu/drm/i915/i915_irq.c | 32 +++++++++++++++++++++----------- > 1 file changed, 21 insertions(+), 11 deletions(-) > > diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c > index 46aaef5c1851..56a080bc4498 100644 > --- a/drivers/gpu/drm/i915/i915_irq.c > +++ b/drivers/gpu/drm/i915/i915_irq.c > @@ -1145,21 +1145,23 @@ static void ironlake_rps_change_irq_handler(struct > drm_i915_private *dev_priv) > > static void notify_ring(struct intel_engine_cs *engine) > { > + const u32 seqno = intel_engine_get_seqno(engine); > struct i915_request *rq = NULL; > + struct task_struct *tsk = NULL; > struct intel_wait *wait; > > - if (!engine->breadcrumbs.irq_armed) > + if (unlikely(!engine->breadcrumbs.irq_armed)) > return; > > atomic_inc(&engine->irq_count); > - set_bit(ENGINE_IRQ_BREADCRUMB, &engine->irq_posted); > + > + rcu_read_lock(); > > spin_lock(&engine->breadcrumbs.irq_lock); > wait = engine->breadcrumbs.irq_wait; > if (wait) { > - bool wakeup = engine->irq_seqno_barrier; > - > - /* We use a callback from the dma-fence to submit > + /* > + * We use a callback from the dma-fence to submit > * requests after waiting on our own requests. To > * ensure minimum delay in queuing the next request to > * hardware, signal the fence now rather than wait for > @@ -1170,19 +1172,22 @@ static void notify_ring(struct intel_engine_cs > *engine) > * and to handle coalescing of multiple seqno updates > * and many waiters. > */ > - if (i915_seqno_passed(intel_engine_get_seqno(engine), > - wait->seqno)) { > + if (i915_seqno_passed(seqno, wait->seqno)) { > struct i915_request *waiter = wait->request; > > - wakeup = true; > if (!test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, > &waiter->fence.flags) && > intel_wait_check_request(wait, waiter)) > rq = i915_request_get(waiter); > - } > > - if (wakeup) > - wake_up_process(wait->tsk); > + tsk = wait->tsk; > + } else { > + if (engine->irq_seqno_barrier) { > + set_bit(ENGINE_IRQ_BREADCRUMB, > + &engine->irq_posted); > + tsk = wait->tsk; > + } > + } > } else { > if (engine->breadcrumbs.irq_armed) > __intel_engine_disarm_breadcrumbs(engine); > @@ -1195,6 +1200,11 @@ static void notify_ring(struct intel_engine_cs *engine) > i915_request_put(rq); > } > > + if (tsk && tsk->state & TASK_NORMAL) > + wake_up_process(tsk); > + > + rcu_read_unlock(); > + > trace_intel_engine_notify(engine, wait); > } > > -- > 2.18.0 _______________________________________________ Intel-gfx mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/intel-gfx
