On 18/09/2017 17:27, Chris Wilson wrote:
As we now check if the seqno is complete in order to signal the fence, we can also decide not to wake up the first_waiter until it is ready (since it is waiting on the same seqno). The only caveat is that if we need the engine->irq_seqno_barrier to enforce some coherency between an interrupt and the seqno read, we have to always wake the waiter in order to perform that heavyweight barrier. Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx> --- drivers/gpu/drm/i915/i915_irq.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c index 4d0e8f76ed1a..bb69c5b0efc4 100644 --- a/drivers/gpu/drm/i915/i915_irq.c +++ b/drivers/gpu/drm/i915/i915_irq.c @@ -1038,6 +1038,8 @@ static void notify_ring(struct intel_engine_cs *engine) 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 * requests after waiting on our own requests. To * ensure minimum delay in queuing the next request to @@ -1050,12 +1052,15 @@ static void notify_ring(struct intel_engine_cs *engine) * and many waiters. */ if (i915_seqno_passed(intel_engine_get_seqno(engine), - wait->seqno) && - !test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, - &wait->request->fence.flags)) - rq = i915_gem_request_get(wait->request); + wait->seqno)) { + wakeup = true; + if (!test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, + &wait->request->fence.flags)) + rq = i915_gem_request_get(wait->request); + }- wake_up_process(wait->tsk);+ if (wakeup) + wake_up_process(wait->tsk); } else { __intel_engine_disarm_breadcrumbs(engine); }
Looks straightforward enough. Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx> Regards, Tvrtko _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
