On Fri, Feb 17, 2017 at 10:48:50AM +0000, Tvrtko Ursulin wrote: > > On 17/02/2017 10:18, Chris Wilson wrote: > >If the waiter was currently running, assume it hasn't had a chance > >to process the pending interupt (e.g, low priority task on a loaded > >system) and wait until it sleeps before declaring a missed interrupt. > > > >References: https://bugs.freedesktop.org/show_bug.cgi?id=99816 > >Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> > >Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx> > >Cc: Mika Kuoppala <mika.kuoppala@xxxxxxxxxxxxxxx> > >--- > > drivers/gpu/drm/i915/intel_breadcrumbs.c | 9 +++++++++ > > 1 file changed, 9 insertions(+) > > > >diff --git a/drivers/gpu/drm/i915/intel_breadcrumbs.c b/drivers/gpu/drm/i915/intel_breadcrumbs.c > >index 4395b177493e..2ad29fb77b2d 100644 > >--- a/drivers/gpu/drm/i915/intel_breadcrumbs.c > >+++ b/drivers/gpu/drm/i915/intel_breadcrumbs.c > >@@ -45,6 +45,15 @@ static void intel_breadcrumbs_hangcheck(unsigned long data) > > return; > > } > > > >+ /* If the waiter was currently running, assume it hasn't had a chance > >+ * to process the pending interupt (e.g, low priority task on a loaded > >+ * system) and wait until it sleeps before declaring a missed interrupt. > >+ */ > >+ if (!intel_engine_wakeup(engine)) { > >+ mod_timer(&b->hangcheck, wait_timeout()); > >+ return; > >+ } > >+ > > DRM_DEBUG("Hangcheck timer elapsed... %s idle\n", engine->name); > > set_bit(engine->id, &engine->i915->gpu_error.missed_irq_rings); > > mod_timer(&engine->breadcrumbs.fake_irq, jiffies + 1); > > > > Change here is that we would never declare a GPU hang is userspace > would just wait indefinitely, or in other words with this patch we > would rely on userspace timing out on their waits in order to > declare a hang. Surely you mean the other way around? The only way we get to now declare a missed-interrupt and then queue a hangcheck here is if userspace sleeps. > Hm, in fact even with the current code, if the userspace keeps > exiting and re-entering the wait we would be re-arming the hangcheck > timer and so also never notice a GPU hang. Correct. It is not the only way we arm the GPU hangcheck. gem_busy/hang, gem_wait/busy-hang check that we do detect hangs even if userspace never sleeps. -Chris -- Chris Wilson, Intel Open Source Technology Centre _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
