[Intel-gfx] [PATCH 02/10] drm/i915: Kick hangcheck from retire worker

[Chris Wilson]

Let's ensure that we cannot run indefinitely without the hangcheck
worker being queued. We removed it from being kicked on every request
because we were kicking it a few millions times in every hangcheck
interval and only once is necessary! However, that leaves us with the
issue of what if userspace never waits for a request, or runs out of
resources, what if userspace just issues a request then spins on
BUSY_IOCTL?

Testcase: igt/gem_busy
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
---
 drivers/gpu/drm/i915/i915_gem.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 7fd44980798f..adeca0ec4cfb 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -3281,10 +3281,12 @@ i915_gem_retire_work_handler(struct work_struct *work)
 	 * We do not need to do this test under locking as in the worst-case
 	 * we queue the retire worker once too often.
 	 */
-	if (READ_ONCE(dev_priv->gt.awake))
+	if (READ_ONCE(dev_priv->gt.awake)) {
+		i915_queue_hangcheck(dev_priv);
 		queue_delayed_work(dev_priv->wq,
 				   &dev_priv->gt.retire_work,
 				   round_jiffies_up_relative(HZ));
+	}
 }
 
 static void
-- 
2.8.1