drm/i915: Adapt workqueue to new alloc_workqueue interface
create_singlethreaded_workqueue() is being phased out for a new
concurrency managed task infrastructure.
Adapt our workqueue constructor to explicitly create a domain that only
allows the execution of a single task at any time. All the tasks are
expected to require the dev->struct_mutex, so would block concurrency of
other tasks if we allow more than a single i915 task to be run at once.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index 428c75b..7c7d1bc 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -1951,7 +1951,22 @@
prealloc_size = dev_priv->mm.gtt->gtt_stolen_entries << PAGE_SHIFT;
agp_size = dev_priv->mm.gtt->gtt_mappable_entries << PAGE_SHIFT;
- dev_priv->wq = create_singlethread_workqueue("i915");
+ /* 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_gem_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 hangcheck.
+ *
+ * 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: max_active = 1 and NON_REENTRANT.
+ */
+ dev_priv->wq = alloc_workqueue("i915",
+ WQ_UNBOUND | WQ_NON_REENTRANT,
+ 1);
if (dev_priv->wq == NULL) {
DRM_ERROR("Failed to create our workqueue.\n");
ret = -ENOMEM;