On 01/27/2015 11:40 AM, Chris Wilson wrote:
On Tue, Jan 27, 2015 at 11:29:36AM +0000, Tvrtko Ursulin wrote:+static void i915_gem_request_unreference_worker(struct work_struct *work) +{ + struct drm_i915_gem_request *req = + container_of(work, struct drm_i915_gem_request, unref_work); + struct drm_device *dev = req->ring->dev; + + mutex_lock(&dev->struct_mutex); + i915_gem_request_unreference(req); + mutex_unlock(&dev->struct_mutex); +} + +static int +i915_fence_ring_check(wait_queue_t *wait, unsigned mode, int flags, void *key) +{ + struct drm_i915_gem_request *req = wait->private; + struct intel_engine_cs *ring = req->ring; + + if (!i915_gem_request_completed(req, false)) + return 0; + + fence_signal_locked(&req->fence); + + __remove_wait_queue(&ring->irq_queue, wait); + ring->irq_put(ring); + + INIT_WORK(&req->unref_work, i915_gem_request_unreference_worker); + schedule_work(&req->unref_work); + + return 0; +} + +static bool i915_fence_ring_enable_signaling(struct fence *fence) +{ + struct drm_i915_gem_request *req = to_i915_request(fence); + struct intel_engine_cs *ring = req->ring; + struct drm_i915_private *dev_priv = ring->dev->dev_private; + wait_queue_t *wait = &req->wait; + + /* queue fence wait queue on irq queue and get fence */ + if (i915_gem_request_completed(req, false) || + i915_terminally_wedged(&dev_priv->gpu_error)) + return false; + + if (!ring->irq_get(ring)) + return false; + + if (i915_gem_request_completed(req, false)) { + ring->irq_put(ring); + return true; + } + + wait->flags = 0; + wait->private = req; + wait->func = i915_fence_ring_check; + + i915_gem_request_reference(req); + + __add_wait_queue(&ring->irq_queue, wait); + + return true; +}Explain how fence_release interacts with enable_signalling. Presumably either the core fence routines cleanup the outstanding signalling, or we are expected to. Doing so will remove the requirement for the extra ref/unref (including the worker).
I think normally we would be expected to use fence_get/put on the signaling side of things but that is not possible here since struct fence is embedded in the request.
So as it is, sync_fence_release will tear everything down with our callback still on the irq_queue which is what taking a request reference sorts out.
Regards, Tvrtko _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
