Commit 299259a3 authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915: Store the reset counter when constructing a request 



As the request is only valid during the same global reset epoch, we can
record the current reset_counter when constructing the request and reuse
it when waiting upon that request in future. This removes a very hairy
atomic check serialised by the struct_mutex at the time of waiting and
allows us to transfer those waits to a central dispatcher for all
waiters and all requests.

PS: With per-engine resets, we obviously cannot assume a global reset
epoch for the requests - a per-engine epoch makes the most sense. The
challenge then is how to handle checking in the waiter for when to break
the wait, as the fine-grained reset may also want to requeue the
request (i.e. the assumption that just because the epoch changes the
request is completed may be broken - or we just avoid breaking that
assumption with the fine-grained resets).

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1460565315-7748-7-git-send-email-chris@chris-wilson.co.uk
parent d98c52cf

drivers/gpu/drm/i915/i915_drv.h

+1 −1
Original line number Diff line number Diff line
@@ -2250,6 +2250,7 @@ struct drm_i915_gem_request { 
	/** On Which ring this request was generated */

	struct drm_i915_private *i915;

	struct intel_engine_cs *engine;

	unsigned reset_counter;



	 /** GEM sequence number associated with the previous request,

	  * when the HWS breadcrumb is equal to this the GPU is processing
@@ -3160,7 +3161,6 @@ void __i915_add_request(struct drm_i915_gem_request *req, 
#define i915_add_request_no_flush(req) \

	__i915_add_request(req, NULL, false)

int __i915_wait_request(struct drm_i915_gem_request *req,

			unsigned reset_counter,

			bool interruptible,

			s64 *timeout,

			struct intel_rps_client *rps);

drivers/gpu/drm/i915/i915_gem.c

+13 −27
Original line number Diff line number Diff line
@@ -1213,7 +1213,6 @@ static int __i915_spin_request(struct drm_i915_gem_request *req, int state) 
/**

 * __i915_wait_request - wait until execution of request has finished

 * @req: duh!

 * @reset_counter: reset sequence associated with the given request

 * @interruptible: do an interruptible wait (normally yes)

 * @timeout: in - how long to wait (NULL forever); out - how much time remaining

 *
@@ -1228,7 +1227,6 @@ static int __i915_spin_request(struct drm_i915_gem_request *req, int state) 
 * errno with remaining time filled in timeout argument.

 */

int __i915_wait_request(struct drm_i915_gem_request *req,

			unsigned reset_counter,

			bool interruptible,

			s64 *timeout,

			struct intel_rps_client *rps)
@@ -1290,7 +1288,7 @@ int __i915_wait_request(struct drm_i915_gem_request *req, 


		/* We need to check whether any gpu reset happened in between

		 * the caller grabbing the seqno and now ... */

		if (reset_counter != i915_reset_counter(&dev_priv->gpu_error)) {

		if (req->reset_counter != i915_reset_counter(&dev_priv->gpu_error)) {

			/* ... but upgrade the -EAGAIN to an -EIO if the gpu

			 * is truely gone. */

			ret = i915_gem_check_wedge(&dev_priv->gpu_error, interruptible);
@@ -1460,13 +1458,7 @@ i915_wait_request(struct drm_i915_gem_request *req) 


	BUG_ON(!mutex_is_locked(&dev->struct_mutex));



	ret = i915_gem_check_wedge(&dev_priv->gpu_error, interruptible);

	if (ret)

		return ret;



	ret = __i915_wait_request(req,

				  i915_reset_counter(&dev_priv->gpu_error),

				  interruptible, NULL, NULL);

	ret = __i915_wait_request(req, interruptible, NULL, NULL);

	if (ret)

		return ret;
@@ -1541,7 +1533,6 @@ i915_gem_object_wait_rendering__nonblocking(struct drm_i915_gem_object *obj, 
	struct drm_device *dev = obj->base.dev;

	struct drm_i915_private *dev_priv = dev->dev_private;

	struct drm_i915_gem_request *requests[I915_NUM_ENGINES];

	unsigned reset_counter;

	int ret, i, n = 0;



	BUG_ON(!mutex_is_locked(&dev->struct_mutex));
@@ -1550,12 +1541,6 @@ i915_gem_object_wait_rendering__nonblocking(struct drm_i915_gem_object *obj, 
	if (!obj->active)

		return 0;



	ret = i915_gem_check_wedge(&dev_priv->gpu_error, true);

	if (ret)

		return ret;



	reset_counter = i915_reset_counter(&dev_priv->gpu_error);



	if (readonly) {

		struct drm_i915_gem_request *req;
@@ -1577,9 +1562,9 @@ i915_gem_object_wait_rendering__nonblocking(struct drm_i915_gem_object *obj, 
	}



	mutex_unlock(&dev->struct_mutex);

	ret = 0;

	for (i = 0; ret == 0 && i < n; i++)

		ret = __i915_wait_request(requests[i], reset_counter, true,

					  NULL, rps);

		ret = __i915_wait_request(requests[i], true, NULL, rps);

	mutex_lock(&dev->struct_mutex);



	for (i = 0; i < n; i++) {
@@ -2735,6 +2720,7 @@ __i915_gem_request_alloc(struct intel_engine_cs *engine, 
			 struct drm_i915_gem_request **req_out)

{

	struct drm_i915_private *dev_priv = to_i915(engine->dev);

	unsigned reset_counter = i915_reset_counter(&dev_priv->gpu_error);

	struct drm_i915_gem_request *req;

	int ret;
@@ -2743,6 +2729,11 @@ __i915_gem_request_alloc(struct intel_engine_cs *engine, 


	*req_out = NULL;



	ret = i915_gem_check_wedge(&dev_priv->gpu_error,

				   dev_priv->mm.interruptible);

	if (ret)

		return ret;



	req = kmem_cache_zalloc(dev_priv->requests, GFP_KERNEL);

	if (req == NULL)

		return -ENOMEM;
@@ -2754,6 +2745,7 @@ __i915_gem_request_alloc(struct intel_engine_cs *engine, 
	kref_init(&req->ref);

	req->i915 = dev_priv;

	req->engine = engine;

	req->reset_counter = reset_counter;

	req->ctx  = ctx;

	i915_gem_context_reference(req->ctx);
@@ -3132,11 +3124,9 @@ retire: 
int

i915_gem_wait_ioctl(struct drm_device *dev, void *data, struct drm_file *file)

{

	struct drm_i915_private *dev_priv = dev->dev_private;

	struct drm_i915_gem_wait *args = data;

	struct drm_i915_gem_object *obj;

	struct drm_i915_gem_request *req[I915_NUM_ENGINES];

	unsigned reset_counter;

	int i, n = 0;

	int ret;
@@ -3170,7 +3160,6 @@ i915_gem_wait_ioctl(struct drm_device *dev, void *data, struct drm_file *file) 
	}



	drm_gem_object_unreference(&obj->base);

	reset_counter = i915_reset_counter(&dev_priv->gpu_error);



	for (i = 0; i < I915_NUM_ENGINES; i++) {

		if (obj->last_read_req[i] == NULL)
@@ -3183,7 +3172,7 @@ i915_gem_wait_ioctl(struct drm_device *dev, void *data, struct drm_file *file) 


	for (i = 0; i < n; i++) {

		if (ret == 0)

			ret = __i915_wait_request(req[i], reset_counter, true,

			ret = __i915_wait_request(req[i], true,

						  args->timeout_ns > 0 ? &args->timeout_ns : NULL,

						  to_rps_client(file));

		i915_gem_request_unreference__unlocked(req[i]);
@@ -3215,7 +3204,6 @@ __i915_gem_object_sync(struct drm_i915_gem_object *obj, 
	if (!i915_semaphore_is_enabled(obj->base.dev)) {

		struct drm_i915_private *i915 = to_i915(obj->base.dev);

		ret = __i915_wait_request(from_req,

					  i915_reset_counter(&i915->gpu_error),

					  i915->mm.interruptible,

					  NULL,

					  &i915->rps.semaphores);
@@ -4171,7 +4159,6 @@ i915_gem_ring_throttle(struct drm_device *dev, struct drm_file *file) 
	struct drm_i915_file_private *file_priv = file->driver_priv;

	unsigned long recent_enough = jiffies - DRM_I915_THROTTLE_JIFFIES;

	struct drm_i915_gem_request *request, *target = NULL;

	unsigned reset_counter;

	int ret;



	ret = i915_gem_wait_for_error(&dev_priv->gpu_error);
@@ -4196,7 +4183,6 @@ i915_gem_ring_throttle(struct drm_device *dev, struct drm_file *file) 


		target = request;

	}

	reset_counter = i915_reset_counter(&dev_priv->gpu_error);

	if (target)

		i915_gem_request_reference(target);

	spin_unlock(&file_priv->mm.lock);
@@ -4204,7 +4190,7 @@ i915_gem_ring_throttle(struct drm_device *dev, struct drm_file *file) 
	if (target == NULL)

		return 0;



	ret = __i915_wait_request(target, reset_counter, true, NULL, NULL);

	ret = __i915_wait_request(target, true, NULL, NULL);

	if (ret == 0)

		queue_delayed_work(dev_priv->wq, &dev_priv->mm.retire_work, 0);

drivers/gpu/drm/i915/i915_gem_userptr.c

+1 −4
Original line number Diff line number Diff line
@@ -65,7 +65,6 @@ static void wait_rendering(struct drm_i915_gem_object *obj) 
{

	struct drm_device *dev = obj->base.dev;

	struct drm_i915_gem_request *requests[I915_NUM_ENGINES];

	unsigned reset_counter;

	int i, n;



	if (!obj->active)
@@ -82,12 +81,10 @@ static void wait_rendering(struct drm_i915_gem_object *obj) 
		requests[n++] = i915_gem_request_reference(req);

	}



	reset_counter = atomic_read(&to_i915(dev)->gpu_error.reset_counter);

	mutex_unlock(&dev->struct_mutex);



	for (i = 0; i < n; i++)

		__i915_wait_request(requests[i], reset_counter, false,

				    NULL, NULL);

		__i915_wait_request(requests[i], false, NULL, NULL);



	mutex_lock(&dev->struct_mutex);

drivers/gpu/drm/i915/intel_display.c

+1 −6
Original line number Diff line number Diff line
@@ -11365,7 +11365,6 @@ static void intel_mmio_flip_work_func(struct work_struct *work) 


	if (mmio_flip->req) {

		WARN_ON(__i915_wait_request(mmio_flip->req,

					    mmio_flip->crtc->reset_counter,

					    false, NULL,

					    &mmio_flip->i915->rps.mmioflips));

		i915_gem_request_unreference__unlocked(mmio_flip->req);
@@ -13426,9 +13425,6 @@ static int intel_atomic_prepare_commit(struct drm_device *dev, 


	ret = drm_atomic_helper_prepare_planes(dev, state);

	if (!ret && !async && !i915_reset_in_progress_or_wedged(&dev_priv->gpu_error)) {

		u32 reset_counter;



		reset_counter = i915_reset_counter(&dev_priv->gpu_error);

		mutex_unlock(&dev->struct_mutex);



		for_each_plane_in_state(state, plane, plane_state, i) {
@@ -13439,8 +13435,7 @@ static int intel_atomic_prepare_commit(struct drm_device *dev, 
				continue;



			ret = __i915_wait_request(intel_plane_state->wait_req,

						  reset_counter, true,

						  NULL, NULL);

						  true, NULL, NULL);



			/* Swallow -EIO errors to allow updates during hw lockup. */

			if (ret == -EIO)

drivers/gpu/drm/i915/intel_lrc.c

+0 −7
Original line number Diff line number Diff line
@@ -890,16 +890,9 @@ static int logical_ring_prepare(struct drm_i915_gem_request *req, int bytes) 
 */

int intel_logical_ring_begin(struct drm_i915_gem_request *req, int num_dwords)

{

	struct drm_i915_private *dev_priv;

	int ret;



	WARN_ON(req == NULL);

	dev_priv = req->i915;



	ret = i915_gem_check_wedge(&dev_priv->gpu_error,

				   dev_priv->mm.interruptible);

	if (ret)

		return ret;



	ret = logical_ring_prepare(req, num_dwords * sizeof(uint32_t));

	if (ret)

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