[Intel-gfx] [PATCH] drm/i915: Make the GEM reclaim workqueue high priority

[Chris Wilson]

Since removing dev->struct_mutex usage, we only use i915->wq for batch
freeing of GEM objects and ppGTT, it is essential for memory reclaim. If
we let the workqueue dawdle, we trap excess amounts of memory, so give
it a priority boost. Although since we no longer depend on a singular
mutex, we could run unbounded, but first lets try to keep some
constraint upon the worker.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: CQ Tang <cq.tang at intel.com>
---
 drivers/gpu/drm/i915/i915_drv.c | 16 +++-------------
 1 file changed, 3 insertions(+), 13 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 8bb7e2dcfaaa..8c9198f0d2ad 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -219,20 +219,10 @@ intel_teardown_mchbar(struct drm_i915_private *dev_priv)
 static int i915_workqueues_init(struct drm_i915_private *dev_priv)
 {
 	/*
-	 * The i915 workqueue is primarily used for batched retirement of
-	 * requests (and thus managing bo) once the task has been completed
-	 * by the GPU. i915_retire_requests() is called directly when we
-	 * need high-priority retirement, such as waiting for an explicit
-	 * bo.
-	 *
-	 * It is also used for periodic low-priority events, such as
-	 * idle-timers and recording error state.
-	 *
-	 * All tasks on the workqueue are expected to acquire the dev mutex
-	 * so there is no point in running more than one instance of the
-	 * workqueue at any time.  Use an ordered one.
+	 * The i915 workqueue is primarily used for batched freeing of
+	 * GEM objects and ppGTT, and is essential for memory reclaim.
 	 */
-	dev_priv->wq = alloc_ordered_workqueue("i915", 0);
+	dev_priv->wq = alloc_ordered_workqueue("i915", WQ_HIGHPRI);
 	if (dev_priv->wq == NULL)
 		goto out_err;
 
-- 
2.20.1