intel_context.c

  1// SPDX-License-Identifier: MIT
  2/*
  3 * Copyright © 2019 Intel Corporation
  4 */
  5
  6#include "gem/i915_gem_context.h"
  7#include "gem/i915_gem_pm.h"
  8
  9#include "i915_drm_client.h"
 10#include "i915_drv.h"
 11#include "i915_trace.h"
 12
 13#include "intel_context.h"
 14#include "intel_engine.h"
 15#include "intel_engine_pm.h"
 16#include "intel_ring.h"
 17
 18static struct kmem_cache *slab_ce;
 19
 20static struct intel_context *intel_context_alloc(void)
 21{
 22	return kmem_cache_zalloc(slab_ce, GFP_KERNEL);
 23}
 24
 25static void rcu_context_free(struct rcu_head *rcu)
 26{
 27	struct intel_context *ce = container_of(rcu, typeof(*ce), rcu);
 28
 29	trace_intel_context_free(ce);
 30	if (intel_context_has_own_state(ce))
 31		fput(ce->default_state);
 32	kmem_cache_free(slab_ce, ce);
 33}
 34
 35void intel_context_free(struct intel_context *ce)
 36{
 37	call_rcu(&ce->rcu, rcu_context_free);
 38}
 39
 40struct intel_context *
 41intel_context_create(struct intel_engine_cs *engine)
 42{
 43	struct intel_context *ce;
 44
 45	ce = intel_context_alloc();
 46	if (!ce)
 47		return ERR_PTR(-ENOMEM);
 48
 49	intel_context_init(ce, engine);
 50	trace_intel_context_create(ce);
 51	return ce;
 52}
 53
 54int intel_context_alloc_state(struct intel_context *ce)
 55{
 56	struct i915_gem_context *ctx;
 57	int err = 0;
 58
 59	if (mutex_lock_interruptible(&ce->pin_mutex))
 60		return -EINTR;
 61
 62	if (!test_bit(CONTEXT_ALLOC_BIT, &ce->flags)) {
 63		if (intel_context_is_banned(ce)) {
 64			err = -EIO;
 65			goto unlock;
 66		}
 67
 68		err = ce->ops->alloc(ce);
 69		if (unlikely(err))
 70			goto unlock;
 71
 72		set_bit(CONTEXT_ALLOC_BIT, &ce->flags);
 73
 74		rcu_read_lock();
 75		ctx = rcu_dereference(ce->gem_context);
 76		if (ctx && !kref_get_unless_zero(&ctx->ref))
 77			ctx = NULL;
 78		rcu_read_unlock();
 79		if (ctx) {
 80			if (ctx->client)
 81				i915_drm_client_add_context_objects(ctx->client,
 82								    ce);
 83			i915_gem_context_put(ctx);
 84		}
 85	}
 86
 87unlock:
 88	mutex_unlock(&ce->pin_mutex);
 89	return err;
 90}
 91
 92static int intel_context_active_acquire(struct intel_context *ce)
 93{
 94	int err;
 95
 96	__i915_active_acquire(&ce->active);
 97
 98	if (intel_context_is_barrier(ce) || intel_engine_uses_guc(ce->engine) ||
 99	    intel_context_is_parallel(ce))
100		return 0;
101
102	/* Preallocate tracking nodes */
103	err = i915_active_acquire_preallocate_barrier(&ce->active,
104						      ce->engine);
105	if (err)
106		i915_active_release(&ce->active);
107
108	return err;
109}
110
111static void intel_context_active_release(struct intel_context *ce)
112{
113	/* Nodes preallocated in intel_context_active() */
114	i915_active_acquire_barrier(&ce->active);
115	i915_active_release(&ce->active);
116}
117
118static int __context_pin_state(struct i915_vma *vma, struct i915_gem_ww_ctx *ww)
119{
120	unsigned int bias = i915_ggtt_pin_bias(vma) | PIN_OFFSET_BIAS;
121	int err;
122
123	err = i915_ggtt_pin(vma, ww, 0, bias | PIN_HIGH);
124	if (err)
125		return err;
126
127	err = i915_active_acquire(&vma->active);
128	if (err)
129		goto err_unpin;
130
131	/*
132	 * And mark it as a globally pinned object to let the shrinker know
133	 * it cannot reclaim the object until we release it.
134	 */
135	i915_vma_make_unshrinkable(vma);
136	vma->obj->mm.dirty = true;
137
138	return 0;
139
140err_unpin:
141	i915_vma_unpin(vma);
142	return err;
143}
144
145static void __context_unpin_state(struct i915_vma *vma)
146{
147	i915_vma_make_shrinkable(vma);
148	i915_active_release(&vma->active);
149	__i915_vma_unpin(vma);
150}
151
152static int __ring_active(struct intel_ring *ring,
153			 struct i915_gem_ww_ctx *ww)
154{
155	int err;
156
157	err = intel_ring_pin(ring, ww);
158	if (err)
159		return err;
160
161	err = i915_active_acquire(&ring->vma->active);
162	if (err)
163		goto err_pin;
164
165	return 0;
166
167err_pin:
168	intel_ring_unpin(ring);
169	return err;
170}
171
172static void __ring_retire(struct intel_ring *ring)
173{
174	i915_active_release(&ring->vma->active);
175	intel_ring_unpin(ring);
176}
177
178static int intel_context_pre_pin(struct intel_context *ce,
179				 struct i915_gem_ww_ctx *ww)
180{
181	int err;
182
183	CE_TRACE(ce, "active\n");
184
185	err = __ring_active(ce->ring, ww);
186	if (err)
187		return err;
188
189	err = intel_timeline_pin(ce->timeline, ww);
190	if (err)
191		goto err_ring;
192
193	if (!ce->state)
194		return 0;
195
196	err = __context_pin_state(ce->state, ww);
197	if (err)
198		goto err_timeline;
199
200
201	return 0;
202
203err_timeline:
204	intel_timeline_unpin(ce->timeline);
205err_ring:
206	__ring_retire(ce->ring);
207	return err;
208}
209
210static void intel_context_post_unpin(struct intel_context *ce)
211{
212	if (ce->state)
213		__context_unpin_state(ce->state);
214
215	intel_timeline_unpin(ce->timeline);
216	__ring_retire(ce->ring);
217}
218
219int __intel_context_do_pin_ww(struct intel_context *ce,
220			      struct i915_gem_ww_ctx *ww)
221{
222	bool handoff = false;
223	void *vaddr;
224	int err = 0;
225
226	if (unlikely(!test_bit(CONTEXT_ALLOC_BIT, &ce->flags))) {
227		err = intel_context_alloc_state(ce);
228		if (err)
229			return err;
230	}
231
232	/*
233	 * We always pin the context/ring/timeline here, to ensure a pin
234	 * refcount for __intel_context_active(), which prevent a lock
235	 * inversion of ce->pin_mutex vs dma_resv_lock().
236	 */
237
238	err = i915_gem_object_lock(ce->timeline->hwsp_ggtt->obj, ww);
239	if (!err)
240		err = i915_gem_object_lock(ce->ring->vma->obj, ww);
241	if (!err && ce->state)
242		err = i915_gem_object_lock(ce->state->obj, ww);
243	if (!err)
244		err = intel_context_pre_pin(ce, ww);
245	if (err)
246		return err;
247
248	err = ce->ops->pre_pin(ce, ww, &vaddr);
249	if (err)
250		goto err_ctx_unpin;
251
252	err = i915_active_acquire(&ce->active);
253	if (err)
254		goto err_post_unpin;
255
256	err = mutex_lock_interruptible(&ce->pin_mutex);
257	if (err)
258		goto err_release;
259
260	intel_engine_pm_might_get(ce->engine);
261
262	if (unlikely(intel_context_is_closed(ce))) {
263		err = -ENOENT;
264		goto err_unlock;
265	}
266
267	if (likely(!atomic_add_unless(&ce->pin_count, 1, 0))) {
268		err = intel_context_active_acquire(ce);
269		if (unlikely(err))
270			goto err_unlock;
271
272		err = ce->ops->pin(ce, vaddr);
273		if (err) {
274			intel_context_active_release(ce);
275			goto err_unlock;
276		}
277
278		CE_TRACE(ce, "pin ring:{start:%08x, head:%04x, tail:%04x}\n",
279			 i915_ggtt_offset(ce->ring->vma),
280			 ce->ring->head, ce->ring->tail);
281
282		handoff = true;
283		smp_mb__before_atomic(); /* flush pin before it is visible */
284		atomic_inc(&ce->pin_count);
285	}
286
287	GEM_BUG_ON(!intel_context_is_pinned(ce)); /* no overflow! */
288
289	trace_intel_context_do_pin(ce);
290
291err_unlock:
292	mutex_unlock(&ce->pin_mutex);
293err_release:
294	i915_active_release(&ce->active);
295err_post_unpin:
296	if (!handoff)
297		ce->ops->post_unpin(ce);
298err_ctx_unpin:
299	intel_context_post_unpin(ce);
300
301	/*
302	 * Unlock the hwsp_ggtt object since it's shared.
303	 * In principle we can unlock all the global state locked above
304	 * since it's pinned and doesn't need fencing, and will
305	 * thus remain resident until it is explicitly unpinned.
306	 */
307	i915_gem_ww_unlock_single(ce->timeline->hwsp_ggtt->obj);
308
309	return err;
310}
311
312int __intel_context_do_pin(struct intel_context *ce)
313{
314	struct i915_gem_ww_ctx ww;
315	int err;
316
317	i915_gem_ww_ctx_init(&ww, true);
318retry:
319	err = __intel_context_do_pin_ww(ce, &ww);
320	if (err == -EDEADLK) {
321		err = i915_gem_ww_ctx_backoff(&ww);
322		if (!err)
323			goto retry;
324	}
325	i915_gem_ww_ctx_fini(&ww);
326	return err;
327}
328
329void __intel_context_do_unpin(struct intel_context *ce, int sub)
330{
331	if (!atomic_sub_and_test(sub, &ce->pin_count))
332		return;
333
334	CE_TRACE(ce, "unpin\n");
335	ce->ops->unpin(ce);
336	ce->ops->post_unpin(ce);
337
338	/*
339	 * Once released, we may asynchronously drop the active reference.
340	 * As that may be the only reference keeping the context alive,
341	 * take an extra now so that it is not freed before we finish
342	 * dereferencing it.
343	 */
344	intel_context_get(ce);
345	intel_context_active_release(ce);
346	trace_intel_context_do_unpin(ce);
347	intel_context_put(ce);
348}
349
350static void __intel_context_retire(struct i915_active *active)
351{
352	struct intel_context *ce = container_of(active, typeof(*ce), active);
353
354	CE_TRACE(ce, "retire runtime: { total:%lluns, avg:%lluns }\n",
355		 intel_context_get_total_runtime_ns(ce),
356		 intel_context_get_avg_runtime_ns(ce));
357
358	set_bit(CONTEXT_VALID_BIT, &ce->flags);
359	intel_context_post_unpin(ce);
360	intel_context_put(ce);
361}
362
363static int __intel_context_active(struct i915_active *active)
364{
365	struct intel_context *ce = container_of(active, typeof(*ce), active);
366
367	intel_context_get(ce);
368
369	/* everything should already be activated by intel_context_pre_pin() */
370	GEM_WARN_ON(!i915_active_acquire_if_busy(&ce->ring->vma->active));
371	__intel_ring_pin(ce->ring);
372
373	__intel_timeline_pin(ce->timeline);
374
375	if (ce->state) {
376		GEM_WARN_ON(!i915_active_acquire_if_busy(&ce->state->active));
377		__i915_vma_pin(ce->state);
378		i915_vma_make_unshrinkable(ce->state);
379	}
380
381	return 0;
382}
383
384static int
385sw_fence_dummy_notify(struct i915_sw_fence *sf,
386		      enum i915_sw_fence_notify state)
387{
388	return NOTIFY_DONE;
389}
390
391void
392intel_context_init(struct intel_context *ce, struct intel_engine_cs *engine)
393{
394	GEM_BUG_ON(!engine->cops);
395	GEM_BUG_ON(!engine->gt->vm);
396
397	kref_init(&ce->ref);
398
399	ce->engine = engine;
400	ce->ops = engine->cops;
401	ce->sseu = engine->sseu;
402	ce->ring = NULL;
403	ce->ring_size = SZ_4K;
404
405	ewma_runtime_init(&ce->stats.runtime.avg);
406
407	ce->vm = i915_vm_get(engine->gt->vm);
408
409	/* NB ce->signal_link/lock is used under RCU */
410	spin_lock_init(&ce->signal_lock);
411	INIT_LIST_HEAD(&ce->signals);
412
413	mutex_init(&ce->pin_mutex);
414
415	spin_lock_init(&ce->guc_state.lock);
416	INIT_LIST_HEAD(&ce->guc_state.fences);
417	INIT_LIST_HEAD(&ce->guc_state.requests);
418
419	ce->guc_id.id = GUC_INVALID_CONTEXT_ID;
420	INIT_LIST_HEAD(&ce->guc_id.link);
421
422	INIT_LIST_HEAD(&ce->destroyed_link);
423
424	INIT_LIST_HEAD(&ce->parallel.child_list);
425
426	/*
427	 * Initialize fence to be complete as this is expected to be complete
428	 * unless there is a pending schedule disable outstanding.
429	 */
430	i915_sw_fence_init(&ce->guc_state.blocked,
431			   sw_fence_dummy_notify);
432	i915_sw_fence_commit(&ce->guc_state.blocked);
433
434	i915_active_init(&ce->active,
435			 __intel_context_active, __intel_context_retire, 0);
436}
437
438void intel_context_fini(struct intel_context *ce)
439{
440	struct intel_context *child, *next;
441
442	if (ce->timeline)
443		intel_timeline_put(ce->timeline);
444	i915_vm_put(ce->vm);
445
446	/* Need to put the creation ref for the children */
447	if (intel_context_is_parent(ce))
448		for_each_child_safe(ce, child, next)
449			intel_context_put(child);
450
451	mutex_destroy(&ce->pin_mutex);
452	i915_active_fini(&ce->active);
453	i915_sw_fence_fini(&ce->guc_state.blocked);
454}
455
456void i915_context_module_exit(void)
457{
458	kmem_cache_destroy(slab_ce);
459}
460
461int __init i915_context_module_init(void)
462{
463	slab_ce = KMEM_CACHE(intel_context, SLAB_HWCACHE_ALIGN);
464	if (!slab_ce)
465		return -ENOMEM;
466
467	return 0;
468}
469
470void intel_context_enter_engine(struct intel_context *ce)
471{
472	intel_engine_pm_get(ce->engine);
473	intel_timeline_enter(ce->timeline);
474}
475
476void intel_context_exit_engine(struct intel_context *ce)
477{
478	intel_timeline_exit(ce->timeline);
479	intel_engine_pm_put(ce->engine);
480}
481
482int intel_context_prepare_remote_request(struct intel_context *ce,
483					 struct i915_request *rq)
484{
485	struct intel_timeline *tl = ce->timeline;
486	int err;
487
488	/* Only suitable for use in remotely modifying this context */
489	GEM_BUG_ON(rq->context == ce);
490
491	if (rcu_access_pointer(rq->timeline) != tl) { /* timeline sharing! */
492		/* Queue this switch after current activity by this context. */
493		err = i915_active_fence_set(&tl->last_request, rq);
494		if (err)
495			return err;
496	}
497
498	/*
499	 * Guarantee context image and the timeline remains pinned until the
500	 * modifying request is retired by setting the ce activity tracker.
501	 *
502	 * But we only need to take one pin on the account of it. Or in other
503	 * words transfer the pinned ce object to tracked active request.
504	 */
505	GEM_BUG_ON(i915_active_is_idle(&ce->active));
506	return i915_active_add_request(&ce->active, rq);
507}
508
509struct i915_request *intel_context_create_request(struct intel_context *ce)
510{
511	struct i915_gem_ww_ctx ww;
512	struct i915_request *rq;
513	int err;
514
515	i915_gem_ww_ctx_init(&ww, true);
516retry:
517	err = intel_context_pin_ww(ce, &ww);
518	if (!err) {
519		rq = i915_request_create(ce);
520		intel_context_unpin(ce);
521	} else if (err == -EDEADLK) {
522		err = i915_gem_ww_ctx_backoff(&ww);
523		if (!err)
524			goto retry;
525		rq = ERR_PTR(err);
526	} else {
527		rq = ERR_PTR(err);
528	}
529
530	i915_gem_ww_ctx_fini(&ww);
531
532	if (IS_ERR(rq))
533		return rq;
534
535	/*
536	 * timeline->mutex should be the inner lock, but is used as outer lock.
537	 * Hack around this to shut up lockdep in selftests..
538	 */
539	lockdep_unpin_lock(&ce->timeline->mutex, rq->cookie);
540	mutex_release(&ce->timeline->mutex.dep_map, _RET_IP_);
541	mutex_acquire(&ce->timeline->mutex.dep_map, SINGLE_DEPTH_NESTING, 0, _RET_IP_);
542	rq->cookie = lockdep_pin_lock(&ce->timeline->mutex);
543
544	return rq;
545}
546
547struct i915_request *intel_context_get_active_request(struct intel_context *ce)
548{
549	struct intel_context *parent = intel_context_to_parent(ce);
550	struct i915_request *rq, *active = NULL;
551	unsigned long flags;
552
553	GEM_BUG_ON(!intel_engine_uses_guc(ce->engine));
554
555	/*
556	 * We search the parent list to find an active request on the submitted
557	 * context. The parent list contains the requests for all the contexts
558	 * in the relationship so we have to do a compare of each request's
559	 * context.
560	 */
561	spin_lock_irqsave(&parent->guc_state.lock, flags);
562	list_for_each_entry_reverse(rq, &parent->guc_state.requests,
563				    sched.link) {
564		if (rq->context != ce)
565			continue;
566		if (i915_request_completed(rq))
567			break;
568
569		active = rq;
570	}
571	if (active)
572		active = i915_request_get_rcu(active);
573	spin_unlock_irqrestore(&parent->guc_state.lock, flags);
574
575	return active;
576}
577
578void intel_context_bind_parent_child(struct intel_context *parent,
579				     struct intel_context *child)
580{
581	/*
582	 * Callers responsibility to validate that this function is used
583	 * correctly but we use GEM_BUG_ON here ensure that they do.
584	 */
585	GEM_BUG_ON(intel_context_is_pinned(parent));
586	GEM_BUG_ON(intel_context_is_child(parent));
587	GEM_BUG_ON(intel_context_is_pinned(child));
588	GEM_BUG_ON(intel_context_is_child(child));
589	GEM_BUG_ON(intel_context_is_parent(child));
590
591	parent->parallel.child_index = parent->parallel.number_children++;
592	list_add_tail(&child->parallel.child_link,
593		      &parent->parallel.child_list);
594	child->parallel.parent = parent;
595}
596
597u64 intel_context_get_total_runtime_ns(struct intel_context *ce)
598{
599	u64 total, active;
600
601	if (ce->ops->update_stats)
602		ce->ops->update_stats(ce);
603
604	total = ce->stats.runtime.total;
605	if (ce->ops->flags & COPS_RUNTIME_CYCLES)
606		total *= ce->engine->gt->clock_period_ns;
607
608	active = READ_ONCE(ce->stats.active);
609	if (active)
610		active = intel_context_clock() - active;
611
612	return total + active;
613}
614
615u64 intel_context_get_avg_runtime_ns(struct intel_context *ce)
616{
617	u64 avg = ewma_runtime_read(&ce->stats.runtime.avg);
618
619	if (ce->ops->flags & COPS_RUNTIME_CYCLES)
620		avg *= ce->engine->gt->clock_period_ns;
621
622	return avg;
623}
624
625bool intel_context_ban(struct intel_context *ce, struct i915_request *rq)
626{
627	bool ret = intel_context_set_banned(ce);
628
629	trace_intel_context_ban(ce);
630
631	if (ce->ops->revoke)
632		ce->ops->revoke(ce, rq,
633				INTEL_CONTEXT_BANNED_PREEMPT_TIMEOUT_MS);
634
635	return ret;
636}
637
638bool intel_context_revoke(struct intel_context *ce)
639{
640	bool ret = intel_context_set_exiting(ce);
641
642	if (ce->ops->revoke)
643		ce->ops->revoke(ce, NULL, ce->engine->props.preempt_timeout_ms);
644
645	return ret;
646}
647
648#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
649#include "selftest_context.c"
650#endif