drm/i915: Move GEM request routines to i915_gem_request.c

Migrate the request operations out of the main body of i915_gem.c and
into their own C file for easier expansion.

v2: Move __i915_add_request() across as well

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Acked-by: Mika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1469002875-2335-1-git-send-email-chris@chris-wilson.co.uk

1 files changed, 7 insertions, 648 deletions

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index e40fab114bf0..6df14058b3fe 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1325,365 +1325,6 @@ put_rpm:
 	return ret;
 }
 
-static int
-i915_gem_check_wedge(unsigned reset_counter, bool interruptible)
-{
-	if (__i915_terminally_wedged(reset_counter))
-		return -EIO;
-
-	if (__i915_reset_in_progress(reset_counter)) {
-		/* Non-interruptible callers can't handle -EAGAIN, hence return
-		 * -EIO unconditionally for these. */
-		if (!interruptible)
-			return -EIO;
-
-		return -EAGAIN;
-	}
-
-	return 0;
-}
-
-static unsigned long local_clock_us(unsigned *cpu)
-{
-	unsigned long t;
-
-	/* Cheaply and approximately convert from nanoseconds to microseconds.
-	 * The result and subsequent calculations are also defined in the same
-	 * approximate microseconds units. The principal source of timing
-	 * error here is from the simple truncation.
-	 *
-	 * Note that local_clock() is only defined wrt to the current CPU;
-	 * the comparisons are no longer valid if we switch CPUs. Instead of
-	 * blocking preemption for the entire busywait, we can detect the CPU
-	 * switch and use that as indicator of system load and a reason to
-	 * stop busywaiting, see busywait_stop().
-	 */
-	*cpu = get_cpu();
-	t = local_clock() >> 10;
-	put_cpu();
-
-	return t;
-}
-
-static bool busywait_stop(unsigned long timeout, unsigned cpu)
-{
-	unsigned this_cpu;
-
-	if (time_after(local_clock_us(&this_cpu), timeout))
-		return true;
-
-	return this_cpu != cpu;
-}
-
-bool __i915_spin_request(const struct drm_i915_gem_request *req,
-			 int state, unsigned long timeout_us)
-{
-	unsigned cpu;
-
-	/* When waiting for high frequency requests, e.g. during synchronous
-	 * rendering split between the CPU and GPU, the finite amount of time
-	 * required to set up the irq and wait upon it limits the response
-	 * rate. By busywaiting on the request completion for a short while we
-	 * can service the high frequency waits as quick as possible. However,
-	 * if it is a slow request, we want to sleep as quickly as possible.
-	 * The tradeoff between waiting and sleeping is roughly the time it
-	 * takes to sleep on a request, on the order of a microsecond.
-	 */
-
-	timeout_us += local_clock_us(&cpu);
-	do {
-		if (i915_gem_request_completed(req))
-			return true;
-
-		if (signal_pending_state(state, current))
-			break;
-
-		if (busywait_stop(timeout_us, cpu))
-			break;
-
-		cpu_relax_lowlatency();
-	} while (!need_resched());
-
-	return false;
-}
-
-/**
- * __i915_wait_request - wait until execution of request has finished
- * @req: duh!
- * @interruptible: do an interruptible wait (normally yes)
- * @timeout: in - how long to wait (NULL forever); out - how much time remaining
- * @rps: RPS client
- *
- * Note: It is of utmost importance that the passed in seqno and reset_counter
- * values have been read by the caller in an smp safe manner. Where read-side
- * locks are involved, it is sufficient to read the reset_counter before
- * unlocking the lock that protects the seqno. For lockless tricks, the
- * reset_counter _must_ be read before, and an appropriate smp_rmb must be
- * inserted.
- *
- * Returns 0 if the request was found within the alloted time. Else returns the
- * errno with remaining time filled in timeout argument.
- */
-int __i915_wait_request(struct drm_i915_gem_request *req,
-			bool interruptible,
-			s64 *timeout,
-			struct intel_rps_client *rps)
-{
-	int state = interruptible ? TASK_INTERRUPTIBLE : TASK_UNINTERRUPTIBLE;
-	DEFINE_WAIT(reset);
-	struct intel_wait wait;
-	unsigned long timeout_remain;
-	s64 before = 0; /* Only to silence a compiler warning. */
-	int ret = 0;
-
-	might_sleep();
-
-	if (list_empty(&req->list))
-		return 0;
-
-	if (i915_gem_request_completed(req))
-		return 0;
-
-	timeout_remain = MAX_SCHEDULE_TIMEOUT;
-	if (timeout) {
-		if (WARN_ON(*timeout < 0))
-			return -EINVAL;
-
-		if (*timeout == 0)
-			return -ETIME;
-
-		timeout_remain = nsecs_to_jiffies_timeout(*timeout);
-
-		/*
-		 * Record current time in case interrupted by signal, or wedged.
-		 */
-		before = ktime_get_raw_ns();
-	}
-
-	trace_i915_gem_request_wait_begin(req);
-
-	/* This client is about to stall waiting for the GPU. In many cases
-	 * this is undesirable and limits the throughput of the system, as
-	 * many clients cannot continue processing user input/output whilst
-	 * blocked. RPS autotuning may take tens of milliseconds to respond
-	 * to the GPU load and thus incurs additional latency for the client.
-	 * We can circumvent that by promoting the GPU frequency to maximum
-	 * before we wait. This makes the GPU throttle up much more quickly
-	 * (good for benchmarks and user experience, e.g. window animations),
-	 * but at a cost of spending more power processing the workload
-	 * (bad for battery). Not all clients even want their results
-	 * immediately and for them we should just let the GPU select its own
-	 * frequency to maximise efficiency. To prevent a single client from
-	 * forcing the clocks too high for the whole system, we only allow
-	 * each client to waitboost once in a busy period.
-	 */
-	if (INTEL_INFO(req->i915)->gen >= 6)
-		gen6_rps_boost(req->i915, rps, req->emitted_jiffies);
-
-	/* Optimistic spin for the next ~jiffie before touching IRQs */
-	if (i915_spin_request(req, state, 5))
-		goto complete;
-
-	set_current_state(state);
-	add_wait_queue(&req->i915->gpu_error.wait_queue, &reset);
-
-	intel_wait_init(&wait, req->seqno);
-	if (intel_engine_add_wait(req->engine, &wait))
-		/* In order to check that we haven't missed the interrupt
-		 * as we enabled it, we need to kick ourselves to do a
-		 * coherent check on the seqno before we sleep.
-		 */
-		goto wakeup;
-
-	for (;;) {
-		if (signal_pending_state(state, current)) {
-			ret = -ERESTARTSYS;
-			break;
-		}
-
-		timeout_remain = io_schedule_timeout(timeout_remain);
-		if (timeout_remain == 0) {
-			ret = -ETIME;
-			break;
-		}
-
-		if (intel_wait_complete(&wait))
-			break;
-
-		set_current_state(state);
-
-wakeup:
-		/* Carefully check if the request is complete, giving time
-		 * for the seqno to be visible following the interrupt.
-		 * We also have to check in case we are kicked by the GPU
-		 * reset in order to drop the struct_mutex.
-		 */
-		if (__i915_request_irq_complete(req))
-			break;
-
-		/* Only spin if we know the GPU is processing this request */
-		if (i915_spin_request(req, state, 2))
-			break;
-	}
-	remove_wait_queue(&req->i915->gpu_error.wait_queue, &reset);
-
-	intel_engine_remove_wait(req->engine, &wait);
-	__set_current_state(TASK_RUNNING);
-complete:
-	trace_i915_gem_request_wait_end(req);
-
-	if (timeout) {
-		s64 tres = *timeout - (ktime_get_raw_ns() - before);
-
-		*timeout = tres < 0 ? 0 : tres;
-
-		/*
-		 * Apparently ktime isn't accurate enough and occasionally has a
-		 * bit of mismatch in the jiffies<->nsecs<->ktime loop. So patch
-		 * things up to make the test happy. We allow up to 1 jiffy.
-		 *
-		 * This is a regrssion from the timespec->ktime conversion.
-		 */
-		if (ret == -ETIME && *timeout < jiffies_to_usecs(1)*1000)
-			*timeout = 0;
-	}
-
-	if (rps && req->seqno == req->engine->last_submitted_seqno) {
-		/* The GPU is now idle and this client has stalled.
-		 * Since no other client has submitted a request in the
-		 * meantime, assume that this client is the only one
-		 * supplying work to the GPU but is unable to keep that
-		 * work supplied because it is waiting. Since the GPU is
-		 * then never kept fully busy, RPS autoclocking will
-		 * keep the clocks relatively low, causing further delays.
-		 * Compensate by giving the synchronous client credit for
-		 * a waitboost next time.
-		 */
-		spin_lock(&req->i915->rps.client_lock);
-		list_del_init(&rps->link);
-		spin_unlock(&req->i915->rps.client_lock);
-	}
-
-	return ret;
-}
-
-int i915_gem_request_add_to_client(struct drm_i915_gem_request *req,
-				   struct drm_file *file)
-{
-	struct drm_i915_file_private *file_priv;
-
-	WARN_ON(!req || !file || req->file_priv);
-
-	if (!req || !file)
-		return -EINVAL;
-
-	if (req->file_priv)
-		return -EINVAL;
-
-	file_priv = file->driver_priv;
-
-	spin_lock(&file_priv->mm.lock);
-	req->file_priv = file_priv;
-	list_add_tail(&req->client_list, &file_priv->mm.request_list);
-	spin_unlock(&file_priv->mm.lock);
-
-	req->pid = get_pid(task_pid(current));
-
-	return 0;
-}
-
-static inline void
-i915_gem_request_remove_from_client(struct drm_i915_gem_request *request)
-{
-	struct drm_i915_file_private *file_priv = request->file_priv;
-
-	if (!file_priv)
-		return;
-
-	spin_lock(&file_priv->mm.lock);
-	list_del(&request->client_list);
-	request->file_priv = NULL;
-	spin_unlock(&file_priv->mm.lock);
-
-	put_pid(request->pid);
-	request->pid = NULL;
-}
-
-static void i915_gem_request_retire(struct drm_i915_gem_request *request)
-{
-	trace_i915_gem_request_retire(request);
-
-	/* We know the GPU must have read the request to have
-	 * sent us the seqno + interrupt, so use the position
-	 * of tail of the request to update the last known position
-	 * of the GPU head.
-	 *
-	 * Note this requires that we are always called in request
-	 * completion order.
-	 */
-	request->ringbuf->last_retired_head = request->postfix;
-
-	list_del_init(&request->list);
-	i915_gem_request_remove_from_client(request);
-
-	if (request->previous_context) {
-		if (i915.enable_execlists)
-			intel_lr_context_unpin(request->previous_context,
-					       request->engine);
-	}
-
-	i915_gem_context_unreference(request->ctx);
-	i915_gem_request_unreference(request);
-}
-
-static void
-__i915_gem_request_retire__upto(struct drm_i915_gem_request *req)
-{
-	struct intel_engine_cs *engine = req->engine;
-	struct drm_i915_gem_request *tmp;
-
-	lockdep_assert_held(&engine->i915->drm.struct_mutex);
-
-	if (list_empty(&req->list))
-		return;
-
-	do {
-		tmp = list_first_entry(&engine->request_list,
-				       typeof(*tmp), list);
-
-		i915_gem_request_retire(tmp);
-	} while (tmp != req);
-
-	WARN_ON(i915_verify_lists(engine->dev));
-}
-
-/**
- * Waits for a request to be signaled, and cleans up the
- * request and object lists appropriately for that event.
- * @req: request to wait on
- */
-int
-i915_wait_request(struct drm_i915_gem_request *req)
-{
-	struct drm_i915_private *dev_priv = req->i915;
-	bool interruptible;
-	int ret;
-
-	interruptible = dev_priv->mm.interruptible;
-
-	BUG_ON(!mutex_is_locked(&dev_priv->drm.struct_mutex));
-
-	ret = __i915_wait_request(req, interruptible, NULL, NULL);
-	if (ret)
-		return ret;
-
-	/* If the GPU hung, we want to keep the requests to find the guilty. */
-	if (!i915_reset_in_progress(&dev_priv->gpu_error))
-		__i915_gem_request_retire__upto(req);
-
-	return 0;
-}
-
 /**
  * Ensures that all rendering to the object has completed and the object is
  * safe to unbind from the GTT or access from the CPU.
@@ -1740,7 +1381,7 @@ i915_gem_object_retire_request(struct drm_i915_gem_object *obj,
 		i915_gem_object_retire__write(obj);
 
 	if (!i915_reset_in_progress(&req->i915->gpu_error))
-		__i915_gem_request_retire__upto(req);
+		i915_gem_request_retire_upto(req);
 }
 
 /* A nonblocking variant of the above wait. This is a highly dangerous routine
@@ -2761,193 +2402,6 @@ i915_gem_object_retire__read(struct drm_i915_gem_object *obj, int ring)
 	drm_gem_object_unreference(&obj->base);
 }
 
-static int
-i915_gem_init_seqno(struct drm_i915_private *dev_priv, u32 seqno)
-{
-	struct intel_engine_cs *engine;
-	int ret;
-
-	/* Carefully retire all requests without writing to the rings */
-	for_each_engine(engine, dev_priv) {
-		ret = intel_engine_idle(engine);
-		if (ret)
-			return ret;
-	}
-	i915_gem_retire_requests(dev_priv);
-
-	/* If the seqno wraps around, we need to clear the breadcrumb rbtree */
-	if (!i915_seqno_passed(seqno, dev_priv->next_seqno)) {
-		while (intel_kick_waiters(dev_priv) ||
-		       intel_kick_signalers(dev_priv))
-			yield();
-	}
-
-	/* Finally reset hw state */
-	for_each_engine(engine, dev_priv)
-		intel_ring_init_seqno(engine, seqno);
-
-	return 0;
-}
-
-int i915_gem_set_seqno(struct drm_device *dev, u32 seqno)
-{
-	struct drm_i915_private *dev_priv = to_i915(dev);
-	int ret;
-
-	if (seqno == 0)
-		return -EINVAL;
-
-	/* HWS page needs to be set less than what we
-	 * will inject to ring
-	 */
-	ret = i915_gem_init_seqno(dev_priv, seqno - 1);
-	if (ret)
-		return ret;
-
-	/* Carefully set the last_seqno value so that wrap
-	 * detection still works
-	 */
-	dev_priv->next_seqno = seqno;
-	dev_priv->last_seqno = seqno - 1;
-	if (dev_priv->last_seqno == 0)
-		dev_priv->last_seqno--;
-
-	return 0;
-}
-
-int
-i915_gem_get_seqno(struct drm_i915_private *dev_priv, u32 *seqno)
-{
-	/* reserve 0 for non-seqno */
-	if (dev_priv->next_seqno == 0) {
-		int ret = i915_gem_init_seqno(dev_priv, 0);
-		if (ret)
-			return ret;
-
-		dev_priv->next_seqno = 1;
-	}
-
-	*seqno = dev_priv->last_seqno = dev_priv->next_seqno++;
-	return 0;
-}
-
-static void i915_gem_mark_busy(const struct intel_engine_cs *engine)
-{
-	struct drm_i915_private *dev_priv = engine->i915;
-
-	dev_priv->gt.active_engines |= intel_engine_flag(engine);
-	if (dev_priv->gt.awake)
-		return;
-
-	intel_runtime_pm_get_noresume(dev_priv);
-	dev_priv->gt.awake = true;
-
-	intel_enable_gt_powersave(dev_priv);
-	i915_update_gfx_val(dev_priv);
-	if (INTEL_GEN(dev_priv) >= 6)
-		gen6_rps_busy(dev_priv);
-
-	queue_delayed_work(dev_priv->wq,
-			   &dev_priv->gt.retire_work,
-			   round_jiffies_up_relative(HZ));
-}
-
-/*
- * NB: This function is not allowed to fail. Doing so would mean the the
- * request is not being tracked for completion but the work itself is
- * going to happen on the hardware. This would be a Bad Thing(tm).
- */
-void __i915_add_request(struct drm_i915_gem_request *request,
-			struct drm_i915_gem_object *obj,
-			bool flush_caches)
-{
-	struct intel_engine_cs *engine;
-	struct intel_ringbuffer *ringbuf;
-	u32 request_start;
-	u32 reserved_tail;
-	int ret;
-
-	if (WARN_ON(request == NULL))
-		return;
-
-	engine = request->engine;
-	ringbuf = request->ringbuf;
-
-	/*
-	 * To ensure that this call will not fail, space for its emissions
-	 * should already have been reserved in the ring buffer. Let the ring
-	 * know that it is time to use that space up.
-	 */
-	request_start = intel_ring_get_tail(ringbuf);
-	reserved_tail = request->reserved_space;
-	request->reserved_space = 0;
-
-	/*
-	 * Emit any outstanding flushes - execbuf can fail to emit the flush
-	 * after having emitted the batchbuffer command. Hence we need to fix
-	 * things up similar to emitting the lazy request. The difference here
-	 * is that the flush _must_ happen before the next request, no matter
-	 * what.
-	 */
-	if (flush_caches) {
-		if (i915.enable_execlists)
-			ret = logical_ring_flush_all_caches(request);
-		else
-			ret = intel_ring_flush_all_caches(request);
-		/* Not allowed to fail! */
-		WARN(ret, "*_ring_flush_all_caches failed: %d!\n", ret);
-	}
-
-	trace_i915_gem_request_add(request);
-
-	request->head = request_start;
-
-	/* Whilst this request exists, batch_obj will be on the
-	 * active_list, and so will hold the active reference. Only when this
-	 * request is retired will the the batch_obj be moved onto the
-	 * inactive_list and lose its active reference. Hence we do not need
-	 * to explicitly hold another reference here.
-	 */
-	request->batch_obj = obj;
-
-	/* Seal the request and mark it as pending execution. Note that
-	 * we may inspect this state, without holding any locks, during
-	 * hangcheck. Hence we apply the barrier to ensure that we do not
-	 * see a more recent value in the hws than we are tracking.
-	 */
-	request->emitted_jiffies = jiffies;
-	request->previous_seqno = engine->last_submitted_seqno;
-	smp_store_mb(engine->last_submitted_seqno, request->seqno);
-	list_add_tail(&request->list, &engine->request_list);
-
-	/* Record the position of the start of the request so that
-	 * should we detect the updated seqno part-way through the
-	 * GPU processing the request, we never over-estimate the
-	 * position of the head.
-	 */
-	request->postfix = intel_ring_get_tail(ringbuf);
-
-	if (i915.enable_execlists)
-		ret = engine->emit_request(request);
-	else {
-		ret = engine->add_request(request);
-
-		request->tail = intel_ring_get_tail(ringbuf);
-	}
-	/* Not allowed to fail! */
-	WARN(ret, "emit|add_request failed: %d!\n", ret);
-	/* Sanity check that the reserved size was large enough. */
-	ret = intel_ring_get_tail(ringbuf) - request_start;
-	if (ret < 0)
-		ret += ringbuf->size;
-	WARN_ONCE(ret > reserved_tail,
-		  "Not enough space reserved (%d bytes) "
-		  "for adding the request (%d bytes)\n",
-		  reserved_tail, ret);
-
-	i915_gem_mark_busy(engine);
-}
-
 static bool i915_context_is_banned(const struct i915_gem_context *ctx)
 {
 	unsigned long elapsed;
@@ -2979,101 +2433,6 @@ static void i915_set_reset_status(struct i915_gem_context *ctx,
 	}
 }
 
-void i915_gem_request_free(struct kref *req_ref)
-{
-	struct drm_i915_gem_request *req = container_of(req_ref,
-						 typeof(*req), ref);
-	kmem_cache_free(req->i915->requests, req);
-}
-
-static inline int
-__i915_gem_request_alloc(struct intel_engine_cs *engine,
-			 struct i915_gem_context *ctx,
-			 struct drm_i915_gem_request **req_out)
-{
-	struct drm_i915_private *dev_priv = engine->i915;
-	unsigned reset_counter = i915_reset_counter(&dev_priv->gpu_error);
-	struct drm_i915_gem_request *req;
-	int ret;
-
-	if (!req_out)
-		return -EINVAL;
-
-	*req_out = NULL;
-
-	/* ABI: Before userspace accesses the GPU (e.g. execbuffer), report
-	 * EIO if the GPU is already wedged, or EAGAIN to drop the struct_mutex
-	 * and restart.
-	 */
-	ret = i915_gem_check_wedge(reset_counter, dev_priv->mm.interruptible);
-	if (ret)
-		return ret;
-
-	req = kmem_cache_zalloc(dev_priv->requests, GFP_KERNEL);
-	if (req == NULL)
-		return -ENOMEM;
-
-	ret = i915_gem_get_seqno(engine->i915, &req->seqno);
-	if (ret)
-		goto err;
-
-	kref_init(&req->ref);
-	req->i915 = dev_priv;
-	req->engine = engine;
-	req->ctx  = ctx;
-	i915_gem_context_reference(req->ctx);
-
-	/*
-	 * Reserve space in the ring buffer for all the commands required to
-	 * eventually emit this request. This is to guarantee that the
-	 * i915_add_request() call can't fail. Note that the reserve may need
-	 * to be redone if the request is not actually submitted straight
-	 * away, e.g. because a GPU scheduler has deferred it.
-	 */
-	req->reserved_space = MIN_SPACE_FOR_ADD_REQUEST;
-
-	if (i915.enable_execlists)
-		ret = intel_logical_ring_alloc_request_extras(req);
-	else
-		ret = intel_ring_alloc_request_extras(req);
-	if (ret)
-		goto err_ctx;
-
-	*req_out = req;
-	return 0;
-
-err_ctx:
-	i915_gem_context_unreference(ctx);
-err:
-	kmem_cache_free(dev_priv->requests, req);
-	return ret;
-}
-
-/**
- * i915_gem_request_alloc - allocate a request structure
- *
- * @engine: engine that we wish to issue the request on.
- * @ctx: context that the request will be associated with.
- *       This can be NULL if the request is not directly related to
- *       any specific user context, in which case this function will
- *       choose an appropriate context to use.
- *
- * Returns a pointer to the allocated request if successful,
- * or an error code if not.
- */
-struct drm_i915_gem_request *
-i915_gem_request_alloc(struct intel_engine_cs *engine,
-		       struct i915_gem_context *ctx)
-{
-	struct drm_i915_gem_request *req;
-	int err;
-
-	if (ctx == NULL)
-		ctx = engine->i915->kernel_context;
-	err = __i915_gem_request_alloc(engine, ctx, &req);
-	return err ? ERR_PTR(err) : req;
-}
-
 struct drm_i915_gem_request *
 i915_gem_find_active_request(struct intel_engine_cs *engine)
 {
@@ -3147,14 +2506,14 @@ static void i915_gem_reset_engine_cleanup(struct intel_engine_cs *engine)
 	 * implicit references on things like e.g. ppgtt address spaces through
 	 * the request.
 	 */
-	while (!list_empty(&engine->request_list)) {
+	if (!list_empty(&engine->request_list)) {
 		struct drm_i915_gem_request *request;
 
-		request = list_first_entry(&engine->request_list,
-					   struct drm_i915_gem_request,
-					   list);
+		request = list_last_entry(&engine->request_list,
+					  struct drm_i915_gem_request,
+					  list);
 
-		i915_gem_request_retire(request);
+		i915_gem_request_retire_upto(request);
 	}
 
 	/* Having flushed all requests from all queues, we know that all
@@ -3222,7 +2581,7 @@ i915_gem_retire_requests_ring(struct intel_engine_cs *engine)
 		if (!i915_gem_request_completed(request))
 			break;
 
-		i915_gem_request_retire(request);
+		i915_gem_request_retire_upto(request);
 	}
 
 	/* Move any buffers on the active list that are no longer referenced