i915_gem_request.c 23.2 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
/*
 * Copyright © 2008-2015 Intel Corporation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 *
 */

25 26
#include <linux/prefetch.h>

27 28
#include "i915_drv.h"

29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72
static const char *i915_fence_get_driver_name(struct fence *fence)
{
	return "i915";
}

static const char *i915_fence_get_timeline_name(struct fence *fence)
{
	/* Timelines are bound by eviction to a VM. However, since
	 * we only have a global seqno at the moment, we only have
	 * a single timeline. Note that each timeline will have
	 * multiple execution contexts (fence contexts) as we allow
	 * engines within a single timeline to execute in parallel.
	 */
	return "global";
}

static bool i915_fence_signaled(struct fence *fence)
{
	return i915_gem_request_completed(to_request(fence));
}

static bool i915_fence_enable_signaling(struct fence *fence)
{
	if (i915_fence_signaled(fence))
		return false;

	intel_engine_enable_signaling(to_request(fence));
	return true;
}

static signed long i915_fence_wait(struct fence *fence,
				   bool interruptible,
				   signed long timeout_jiffies)
{
	s64 timeout_ns, *timeout;
	int ret;

	if (timeout_jiffies != MAX_SCHEDULE_TIMEOUT) {
		timeout_ns = jiffies_to_nsecs(timeout_jiffies);
		timeout = &timeout_ns;
	} else {
		timeout = NULL;
	}

73 74 75
	ret = i915_wait_request(to_request(fence),
				interruptible, timeout,
				NO_WAITBOOST);
76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117
	if (ret == -ETIME)
		return 0;

	if (ret < 0)
		return ret;

	if (timeout_jiffies != MAX_SCHEDULE_TIMEOUT)
		timeout_jiffies = nsecs_to_jiffies(timeout_ns);

	return timeout_jiffies;
}

static void i915_fence_value_str(struct fence *fence, char *str, int size)
{
	snprintf(str, size, "%u", fence->seqno);
}

static void i915_fence_timeline_value_str(struct fence *fence, char *str,
					  int size)
{
	snprintf(str, size, "%u",
		 intel_engine_get_seqno(to_request(fence)->engine));
}

static void i915_fence_release(struct fence *fence)
{
	struct drm_i915_gem_request *req = to_request(fence);

	kmem_cache_free(req->i915->requests, req);
}

const struct fence_ops i915_fence_ops = {
	.get_driver_name = i915_fence_get_driver_name,
	.get_timeline_name = i915_fence_get_timeline_name,
	.enable_signaling = i915_fence_enable_signaling,
	.signaled = i915_fence_signaled,
	.wait = i915_fence_wait,
	.release = i915_fence_release,
	.fence_value_str = i915_fence_value_str,
	.timeline_value_str = i915_fence_timeline_value_str,
};

118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161
int i915_gem_request_add_to_client(struct drm_i915_gem_request *req,
				   struct drm_file *file)
{
	struct drm_i915_private *dev_private;
	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;

	dev_private = req->i915;
	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;
}

162 163 164 165 166 167
void i915_gem_retire_noop(struct i915_gem_active *active,
			  struct drm_i915_gem_request *request)
{
	/* Space left intentionally blank */
}

168 169
static void i915_gem_request_retire(struct drm_i915_gem_request *request)
{
170 171
	struct i915_gem_active *active, *next;

172
	trace_i915_gem_request_retire(request);
173
	list_del(&request->link);
174 175 176 177 178 179 180 181 182

	/* 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.
	 */
183
	list_del(&request->ring_link);
184
	request->ring->last_retired_head = request->postfix;
185

186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207
	/* Walk through the active list, calling retire on each. This allows
	 * objects to track their GPU activity and mark themselves as idle
	 * when their *last* active request is completed (updating state
	 * tracking lists for eviction, active references for GEM, etc).
	 *
	 * As the ->retire() may free the node, we decouple it first and
	 * pass along the auxiliary information (to avoid dereferencing
	 * the node after the callback).
	 */
	list_for_each_entry_safe(active, next, &request->active_list, link) {
		/* In microbenchmarks or focusing upon time inside the kernel,
		 * we may spend an inordinate amount of time simply handling
		 * the retirement of requests and processing their callbacks.
		 * Of which, this loop itself is particularly hot due to the
		 * cache misses when jumping around the list of i915_gem_active.
		 * So we try to keep this loop as streamlined as possible and
		 * also prefetch the next i915_gem_active to try and hide
		 * the likely cache miss.
		 */
		prefetchw(next);

		INIT_LIST_HEAD(&active->link);
208
		RCU_INIT_POINTER(active->request, NULL);
209 210 211 212

		active->retire(active, request);
	}

213 214 215 216 217 218 219 220
	i915_gem_request_remove_from_client(request);

	if (request->previous_context) {
		if (i915.enable_execlists)
			intel_lr_context_unpin(request->previous_context,
					       request->engine);
	}

221
	i915_gem_context_put(request->ctx);
222
	i915_gem_request_put(request);
223 224 225 226 227 228 229 230
}

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(&req->i915->drm.struct_mutex);
231
	GEM_BUG_ON(list_empty(&req->link));
232 233 234

	do {
		tmp = list_first_entry(&engine->request_list,
235
				       typeof(*tmp), link);
236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265

		i915_gem_request_retire(tmp);
	} while (tmp != req);
}

static int i915_gem_check_wedge(unsigned int 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 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) {
266
		ret = intel_engine_idle(engine, true);
267 268 269 270 271 272 273 274 275 276 277 278 279 280
		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)
281
		intel_engine_init_seqno(engine, seqno);
282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317

	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;

	dev_priv->next_seqno = seqno;
	return 0;
}

static int i915_gem_get_seqno(struct drm_i915_private *dev_priv, u32 *seqno)
{
	/* reserve 0 for non-seqno */
	if (unlikely(dev_priv->next_seqno == 0)) {
		int ret;

		ret = i915_gem_init_seqno(dev_priv, 0);
		if (ret)
			return ret;

		dev_priv->next_seqno = 1;
	}

318
	*seqno = dev_priv->next_seqno++;
319 320 321
	return 0;
}

322 323 324 325 326 327 328 329 330 331 332 333 334 335 336
/**
 * 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)
337 338 339 340
{
	struct drm_i915_private *dev_priv = engine->i915;
	unsigned int reset_counter = i915_reset_counter(&dev_priv->gpu_error);
	struct drm_i915_gem_request *req;
341
	u32 seqno;
342 343 344 345 346 347 348 349
	int ret;

	/* 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)
350
		return ERR_PTR(ret);
351

352
	/* Move the oldest request to the slab-cache (if not in use!) */
353
	req = list_first_entry_or_null(&engine->request_list,
354
				       typeof(*req), link);
355 356
	if (req && i915_gem_request_completed(req))
		i915_gem_request_retire(req);
357

358 359 360 361 362
	/* Beware: Dragons be flying overhead.
	 *
	 * We use RCU to look up requests in flight. The lookups may
	 * race with the request being allocated from the slab freelist.
	 * That is the request we are writing to here, may be in the process
363
	 * of being read by __i915_gem_active_get_rcu(). As such,
364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386
	 * we have to be very careful when overwriting the contents. During
	 * the RCU lookup, we change chase the request->engine pointer,
	 * read the request->fence.seqno and increment the reference count.
	 *
	 * The reference count is incremented atomically. If it is zero,
	 * the lookup knows the request is unallocated and complete. Otherwise,
	 * it is either still in use, or has been reallocated and reset
	 * with fence_init(). This increment is safe for release as we check
	 * that the request we have a reference to and matches the active
	 * request.
	 *
	 * Before we increment the refcount, we chase the request->engine
	 * pointer. We must not call kmem_cache_zalloc() or else we set
	 * that pointer to NULL and cause a crash during the lookup. If
	 * we see the request is completed (based on the value of the
	 * old engine and seqno), the lookup is complete and reports NULL.
	 * If we decide the request is not completed (new engine or seqno),
	 * then we grab a reference and double check that it is still the
	 * active request - which it won't be and restart the lookup.
	 *
	 * Do not use kmem_cache_zalloc() here!
	 */
	req = kmem_cache_alloc(dev_priv->requests, GFP_KERNEL);
387
	if (!req)
388
		return ERR_PTR(-ENOMEM);
389

390
	ret = i915_gem_get_seqno(dev_priv, &seqno);
391 392 393
	if (ret)
		goto err;

394 395 396 397 398 399 400
	spin_lock_init(&req->lock);
	fence_init(&req->fence,
		   &i915_fence_ops,
		   &req->lock,
		   engine->fence_context,
		   seqno);

401
	INIT_LIST_HEAD(&req->active_list);
402 403
	req->i915 = dev_priv;
	req->engine = engine;
404
	req->ctx = i915_gem_context_get(ctx);
405

406 407 408 409 410 411 412
	/* No zalloc, must clear what we need by hand */
	req->previous_context = NULL;
	req->file_priv = NULL;
	req->batch_obj = NULL;
	req->pid = NULL;
	req->elsp_submitted = 0;

413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428
	/*
	 * 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;

429 430 431 432 433 434 435
	/* 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.
	 */
	req->head = req->ring->tail;

436
	return req;
437 438

err_ctx:
439
	i915_gem_context_put(ctx);
440 441
err:
	kmem_cache_free(dev_priv->requests, req);
442
	return ERR_PTR(ret);
443 444 445 446 447 448 449 450 451 452 453 454 455
}

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;

456
	intel_enable_gt_powersave(dev_priv);
457 458 459 460 461 462 463 464 465 466 467 468 469 470
	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).
 */
471
void __i915_add_request(struct drm_i915_gem_request *request, bool flush_caches)
472
{
473 474
	struct intel_engine_cs *engine = request->engine;
	struct intel_ring *ring = request->ring;
475 476 477 478 479 480 481 482 483
	u32 request_start;
	u32 reserved_tail;
	int ret;

	/*
	 * 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.
	 */
484
	request_start = ring->tail;
485 486 487 488 489 490 491 492 493 494 495
	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) {
496
		ret = engine->emit_flush(request, EMIT_FLUSH);
497

498
		/* Not allowed to fail! */
499
		WARN(ret, "engine->emit_flush() failed: %d!\n", ret);
500 501 502 503 504 505 506 507 508 509 510
	}

	trace_i915_gem_request_add(request);

	/* 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;
511 512
	engine->last_submitted_seqno = request->fence.seqno;
	i915_gem_active_set(&engine->last_request, request);
513
	list_add_tail(&request->link, &engine->request_list);
514
	list_add_tail(&request->ring_link, &ring->request_list);
515

516
	/* Record the position of the start of the breadcrumb so that
517 518
	 * should we detect the updated seqno part-way through the
	 * GPU processing the request, we never over-estimate the
519
	 * position of the ring's HEAD.
520
	 */
521
	request->postfix = ring->tail;
522 523

	/* Not allowed to fail! */
524 525
	ret = engine->emit_request(request);
	WARN(ret, "(%s)->emit_request failed: %d!\n", engine->name, ret);
526

527
	/* Sanity check that the reserved size was large enough. */
528
	ret = ring->tail - request_start;
529
	if (ret < 0)
530
		ret += ring->size;
531 532 533 534 535 536
	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);
537
	engine->submit_request(request);
538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604
}

static unsigned long local_clock_us(unsigned int *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 int cpu)
{
	unsigned int 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 int 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;
}

/**
605
 * i915_wait_request - wait until execution of request has finished
606 607 608 609 610 611 612 613 614 615 616 617 618 619 620
 * @req: duh!
 * @interruptible: do an interruptible wait (normally yes)
 * @timeout: in - how long to wait (NULL forever); out - how much time remaining
 * @rps: client to charge for RPS boosting
 *
 * 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.
 */
621 622 623 624
int i915_wait_request(struct drm_i915_gem_request *req,
		      bool interruptible,
		      s64 *timeout,
		      struct intel_rps_client *rps)
625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666
{
	int state = interruptible ? TASK_INTERRUPTIBLE : TASK_UNINTERRUPTIBLE;
	DEFINE_WAIT(reset);
	struct intel_wait wait;
	unsigned long timeout_remain;
	int ret = 0;

	might_sleep();

	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;

		/* Record current time in case interrupted, or wedged */
		timeout_remain = nsecs_to_jiffies_timeout(*timeout);
		*timeout += 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.
	 */
667
	if (IS_RPS_CLIENT(rps) && INTEL_GEN(req->i915) >= 6)
668 669
		gen6_rps_boost(req->i915, rps, req->emitted_jiffies);

670
	/* Optimistic short spin before touching IRQs */
671 672 673 674 675 676
	if (i915_spin_request(req, state, 5))
		goto complete;

	set_current_state(state);
	add_wait_queue(&req->i915->gpu_error.wait_queue, &reset);

677
	intel_wait_init(&wait, req->fence.seqno);
678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737
	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) {
		*timeout -= ktime_get_raw_ns();
		if (*timeout < 0)
			*timeout = 0;

		/*
		 * 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;
	}

738 739
	if (IS_RPS_USER(rps) &&
	    req->fence.seqno == req->engine->last_submitted_seqno) {
740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756
		/* 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;
}
757

758
static void engine_retire_requests(struct intel_engine_cs *engine)
759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781
{
	struct drm_i915_gem_request *request, *next;

	list_for_each_entry_safe(request, next, &engine->request_list, link) {
		if (!i915_gem_request_completed(request))
			break;

		i915_gem_request_retire(request);
	}
}

void i915_gem_retire_requests(struct drm_i915_private *dev_priv)
{
	struct intel_engine_cs *engine;

	lockdep_assert_held(&dev_priv->drm.struct_mutex);

	if (dev_priv->gt.active_engines == 0)
		return;

	GEM_BUG_ON(!dev_priv->gt.awake);

	for_each_engine(engine, dev_priv) {
782
		engine_retire_requests(engine);
783
		if (!intel_engine_is_active(engine))
784 785 786 787 788 789 790 791
			dev_priv->gt.active_engines &= ~intel_engine_flag(engine);
	}

	if (dev_priv->gt.active_engines == 0)
		queue_delayed_work(dev_priv->wq,
				   &dev_priv->gt.idle_work,
				   msecs_to_jiffies(100));
}