drm/i915: Sleep whilst waiting for the ring

If userspace is submitting so many long running batches that the ring
becomes full, throttle by sleeping for a 1ms before checking for free
space. Simply yielding was causing excessive scheduler overhead whilst
making no progress.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 1 insertions, 1 deletions

diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index d89b88791aac..89004a622f49 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -707,7 +707,7 @@ int intel_wait_ring_buffer(struct drm_device *dev,
                                 master_priv->sarea_priv->perf_boxes |= I915_BOX_WAIT;
                 }
 
-                yield();
+                msleep(1);
         } while (!time_after(jiffies, end));
         trace_i915_ring_wait_end (dev);
         return -EBUSY;