[Intel-gfx] [PATCH 1/4] drm/i915: Wait for the struct_mutex on idling

[Chris Wilson]

When the system is idling, contention for struct_mutex should be low and
so we will be more efficient to wait for a contended mutex than
reschedule.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/i915_gem_pm.c | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem_pm.c b/drivers/gpu/drm/i915/i915_gem_pm.c
index 3554d55dae35..3b6e8d5be8e1 100644
--- a/drivers/gpu/drm/i915/i915_gem_pm.c
+++ b/drivers/gpu/drm/i915/i915_gem_pm.c
@@ -47,13 +47,7 @@ static void idle_work_handler(struct work_struct *work)
 	struct drm_i915_private *i915 =
 		container_of(work, typeof(*i915), gem.idle_work.work);
 
-	if (!mutex_trylock(&i915->drm.struct_mutex)) {
-		/* Currently busy, come back later */
-		mod_delayed_work(i915->wq,
-				 &i915->gem.idle_work,
-				 msecs_to_jiffies(50));
-		return;
-	}
+	mutex_lock(&i915->drm.struct_mutex);
 
 	intel_wakeref_lock(&i915->gt.wakeref);
 	if (!intel_wakeref_active(&i915->gt.wakeref))
-- 
2.20.1