This source file includes following definitions.
- node_to_request
- node_started
- node_signaled
- to_priolist
- assert_priolists
- i915_sched_lookup_priolist
- __i915_priolist_free
- sched_lock_engine
- rq_prio
- need_preempt
- kick_submission
- __i915_schedule
- i915_schedule
- __bump_priority
- i915_schedule_bump_priority
- i915_sched_node_init
- i915_dependency_alloc
- i915_dependency_free
- __i915_sched_node_add_dependency
- i915_sched_node_add_dependency
- i915_sched_node_fini
- i915_global_scheduler_shrink
- i915_global_scheduler_exit
- i915_global_scheduler_init
1
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5
6
7 #include <linux/mutex.h>
8
9 #include "i915_drv.h"
10 #include "i915_globals.h"
11 #include "i915_request.h"
12 #include "i915_scheduler.h"
13
14 static struct i915_global_scheduler {
15 struct i915_global base;
16 struct kmem_cache *slab_dependencies;
17 struct kmem_cache *slab_priorities;
18 } global;
19
20 static DEFINE_SPINLOCK(schedule_lock);
21
22 static const struct i915_request *
23 node_to_request(const struct i915_sched_node *node)
24 {
25 return container_of(node, const struct i915_request, sched);
26 }
27
28 static inline bool node_started(const struct i915_sched_node *node)
29 {
30 return i915_request_started(node_to_request(node));
31 }
32
33 static inline bool node_signaled(const struct i915_sched_node *node)
34 {
35 return i915_request_completed(node_to_request(node));
36 }
37
38 static inline struct i915_priolist *to_priolist(struct rb_node *rb)
39 {
40 return rb_entry(rb, struct i915_priolist, node);
41 }
42
43 static void assert_priolists(struct intel_engine_execlists * const execlists)
44 {
45 struct rb_node *rb;
46 long last_prio, i;
47
48 if (!IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM))
49 return;
50
51 GEM_BUG_ON(rb_first_cached(&execlists->queue) !=
52 rb_first(&execlists->queue.rb_root));
53
54 last_prio = (INT_MAX >> I915_USER_PRIORITY_SHIFT) + 1;
55 for (rb = rb_first_cached(&execlists->queue); rb; rb = rb_next(rb)) {
56 const struct i915_priolist *p = to_priolist(rb);
57
58 GEM_BUG_ON(p->priority >= last_prio);
59 last_prio = p->priority;
60
61 GEM_BUG_ON(!p->used);
62 for (i = 0; i < ARRAY_SIZE(p->requests); i++) {
63 if (list_empty(&p->requests[i]))
64 continue;
65
66 GEM_BUG_ON(!(p->used & BIT(i)));
67 }
68 }
69 }
70
71 struct list_head *
72 i915_sched_lookup_priolist(struct intel_engine_cs *engine, int prio)
73 {
74 struct intel_engine_execlists * const execlists = &engine->execlists;
75 struct i915_priolist *p;
76 struct rb_node **parent, *rb;
77 bool first = true;
78 int idx, i;
79
80 lockdep_assert_held(&engine->active.lock);
81 assert_priolists(execlists);
82
83
84 idx = I915_PRIORITY_COUNT - (prio & I915_PRIORITY_MASK) - 1;
85 prio >>= I915_USER_PRIORITY_SHIFT;
86 if (unlikely(execlists->no_priolist))
87 prio = I915_PRIORITY_NORMAL;
88
89 find_priolist:
90
91 rb = NULL;
92 parent = &execlists->queue.rb_root.rb_node;
93 while (*parent) {
94 rb = *parent;
95 p = to_priolist(rb);
96 if (prio > p->priority) {
97 parent = &rb->rb_left;
98 } else if (prio < p->priority) {
99 parent = &rb->rb_right;
100 first = false;
101 } else {
102 goto out;
103 }
104 }
105
106 if (prio == I915_PRIORITY_NORMAL) {
107 p = &execlists->default_priolist;
108 } else {
109 p = kmem_cache_alloc(global.slab_priorities, GFP_ATOMIC);
110
111 if (unlikely(!p)) {
112 prio = I915_PRIORITY_NORMAL;
113
114
115
116
117
118
119
120
121
122 execlists->no_priolist = true;
123 goto find_priolist;
124 }
125 }
126
127 p->priority = prio;
128 for (i = 0; i < ARRAY_SIZE(p->requests); i++)
129 INIT_LIST_HEAD(&p->requests[i]);
130 rb_link_node(&p->node, rb, parent);
131 rb_insert_color_cached(&p->node, &execlists->queue, first);
132 p->used = 0;
133
134 out:
135 p->used |= BIT(idx);
136 return &p->requests[idx];
137 }
138
139 void __i915_priolist_free(struct i915_priolist *p)
140 {
141 kmem_cache_free(global.slab_priorities, p);
142 }
143
144 struct sched_cache {
145 struct list_head *priolist;
146 };
147
148 static struct intel_engine_cs *
149 sched_lock_engine(const struct i915_sched_node *node,
150 struct intel_engine_cs *locked,
151 struct sched_cache *cache)
152 {
153 const struct i915_request *rq = node_to_request(node);
154 struct intel_engine_cs *engine;
155
156 GEM_BUG_ON(!locked);
157
158
159
160
161
162
163
164 while (locked != (engine = READ_ONCE(rq->engine))) {
165 spin_unlock(&locked->active.lock);
166 memset(cache, 0, sizeof(*cache));
167 spin_lock(&engine->active.lock);
168 locked = engine;
169 }
170
171 GEM_BUG_ON(locked != engine);
172 return locked;
173 }
174
175 static inline int rq_prio(const struct i915_request *rq)
176 {
177 return rq->sched.attr.priority | __NO_PREEMPTION;
178 }
179
180 static inline bool need_preempt(int prio, int active)
181 {
182
183
184
185
186
187
188
189 return prio >= max(I915_PRIORITY_NORMAL, active);
190 }
191
192 static void kick_submission(struct intel_engine_cs *engine,
193 const struct i915_request *rq,
194 int prio)
195 {
196 const struct i915_request *inflight;
197
198
199
200
201
202 if (prio <= engine->execlists.queue_priority_hint)
203 return;
204
205 rcu_read_lock();
206
207
208 inflight = execlists_active(&engine->execlists);
209 if (!inflight)
210 goto unlock;
211
212
213
214
215
216
217
218
219 if (inflight->hw_context == rq->hw_context)
220 goto unlock;
221
222 engine->execlists.queue_priority_hint = prio;
223 if (need_preempt(prio, rq_prio(inflight)))
224 tasklet_hi_schedule(&engine->execlists.tasklet);
225
226 unlock:
227 rcu_read_unlock();
228 }
229
230 static void __i915_schedule(struct i915_sched_node *node,
231 const struct i915_sched_attr *attr)
232 {
233 struct intel_engine_cs *engine;
234 struct i915_dependency *dep, *p;
235 struct i915_dependency stack;
236 const int prio = attr->priority;
237 struct sched_cache cache;
238 LIST_HEAD(dfs);
239
240
241 lockdep_assert_held(&schedule_lock);
242 GEM_BUG_ON(prio == I915_PRIORITY_INVALID);
243
244 if (prio <= READ_ONCE(node->attr.priority))
245 return;
246
247 if (node_signaled(node))
248 return;
249
250 stack.signaler = node;
251 list_add(&stack.dfs_link, &dfs);
252
253
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255
256
257
258
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264
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268
269
270
271 list_for_each_entry(dep, &dfs, dfs_link) {
272 struct i915_sched_node *node = dep->signaler;
273
274
275 if (node_started(node))
276 continue;
277
278
279
280
281
282
283
284 list_for_each_entry(p, &node->signalers_list, signal_link) {
285 GEM_BUG_ON(p == dep);
286
287 if (node_signaled(p->signaler))
288 continue;
289
290 if (prio > READ_ONCE(p->signaler->attr.priority))
291 list_move_tail(&p->dfs_link, &dfs);
292 }
293 }
294
295
296
297
298
299
300
301 if (node->attr.priority == I915_PRIORITY_INVALID) {
302 GEM_BUG_ON(!list_empty(&node->link));
303 node->attr = *attr;
304
305 if (stack.dfs_link.next == stack.dfs_link.prev)
306 return;
307
308 __list_del_entry(&stack.dfs_link);
309 }
310
311 memset(&cache, 0, sizeof(cache));
312 engine = node_to_request(node)->engine;
313 spin_lock(&engine->active.lock);
314
315
316 engine = sched_lock_engine(node, engine, &cache);
317 list_for_each_entry_safe_reverse(dep, p, &dfs, dfs_link) {
318 INIT_LIST_HEAD(&dep->dfs_link);
319
320 node = dep->signaler;
321 engine = sched_lock_engine(node, engine, &cache);
322 lockdep_assert_held(&engine->active.lock);
323
324
325 if (prio <= node->attr.priority || node_signaled(node))
326 continue;
327
328 GEM_BUG_ON(node_to_request(node)->engine != engine);
329
330 node->attr.priority = prio;
331
332 if (list_empty(&node->link)) {
333
334
335
336
337
338
339
340
341 continue;
342 }
343
344 if (!intel_engine_is_virtual(engine) &&
345 !i915_request_is_active(node_to_request(node))) {
346 if (!cache.priolist)
347 cache.priolist =
348 i915_sched_lookup_priolist(engine,
349 prio);
350 list_move_tail(&node->link, cache.priolist);
351 }
352
353
354 kick_submission(engine, node_to_request(node), prio);
355 }
356
357 spin_unlock(&engine->active.lock);
358 }
359
360 void i915_schedule(struct i915_request *rq, const struct i915_sched_attr *attr)
361 {
362 spin_lock_irq(&schedule_lock);
363 __i915_schedule(&rq->sched, attr);
364 spin_unlock_irq(&schedule_lock);
365 }
366
367 static void __bump_priority(struct i915_sched_node *node, unsigned int bump)
368 {
369 struct i915_sched_attr attr = node->attr;
370
371 attr.priority |= bump;
372 __i915_schedule(node, &attr);
373 }
374
375 void i915_schedule_bump_priority(struct i915_request *rq, unsigned int bump)
376 {
377 unsigned long flags;
378
379 GEM_BUG_ON(bump & ~I915_PRIORITY_MASK);
380 if (READ_ONCE(rq->sched.attr.priority) & bump)
381 return;
382
383 spin_lock_irqsave(&schedule_lock, flags);
384 __bump_priority(&rq->sched, bump);
385 spin_unlock_irqrestore(&schedule_lock, flags);
386 }
387
388 void i915_sched_node_init(struct i915_sched_node *node)
389 {
390 INIT_LIST_HEAD(&node->signalers_list);
391 INIT_LIST_HEAD(&node->waiters_list);
392 INIT_LIST_HEAD(&node->link);
393 node->attr.priority = I915_PRIORITY_INVALID;
394 node->semaphores = 0;
395 node->flags = 0;
396 }
397
398 static struct i915_dependency *
399 i915_dependency_alloc(void)
400 {
401 return kmem_cache_alloc(global.slab_dependencies, GFP_KERNEL);
402 }
403
404 static void
405 i915_dependency_free(struct i915_dependency *dep)
406 {
407 kmem_cache_free(global.slab_dependencies, dep);
408 }
409
410 bool __i915_sched_node_add_dependency(struct i915_sched_node *node,
411 struct i915_sched_node *signal,
412 struct i915_dependency *dep,
413 unsigned long flags)
414 {
415 bool ret = false;
416
417 spin_lock_irq(&schedule_lock);
418
419 if (!node_signaled(signal)) {
420 INIT_LIST_HEAD(&dep->dfs_link);
421 dep->signaler = signal;
422 dep->waiter = node;
423 dep->flags = flags;
424
425
426 if (signal->flags & I915_SCHED_HAS_SEMAPHORE_CHAIN &&
427 !node_started(signal))
428 node->flags |= I915_SCHED_HAS_SEMAPHORE_CHAIN;
429
430
431 list_add(&dep->signal_link, &node->signalers_list);
432 list_add_rcu(&dep->wait_link, &signal->waiters_list);
433
434
435
436
437
438
439
440 BUILD_BUG_ON(__NO_PREEMPTION & ~I915_PRIORITY_MASK);
441 if (flags & I915_DEPENDENCY_EXTERNAL)
442 __bump_priority(signal, __NO_PREEMPTION);
443
444 ret = true;
445 }
446
447 spin_unlock_irq(&schedule_lock);
448
449 return ret;
450 }
451
452 int i915_sched_node_add_dependency(struct i915_sched_node *node,
453 struct i915_sched_node *signal)
454 {
455 struct i915_dependency *dep;
456
457 dep = i915_dependency_alloc();
458 if (!dep)
459 return -ENOMEM;
460
461 if (!__i915_sched_node_add_dependency(node, signal, dep,
462 I915_DEPENDENCY_EXTERNAL |
463 I915_DEPENDENCY_ALLOC))
464 i915_dependency_free(dep);
465
466 return 0;
467 }
468
469 void i915_sched_node_fini(struct i915_sched_node *node)
470 {
471 struct i915_dependency *dep, *tmp;
472
473 spin_lock_irq(&schedule_lock);
474
475
476
477
478
479
480
481 list_for_each_entry_safe(dep, tmp, &node->signalers_list, signal_link) {
482 GEM_BUG_ON(!node_signaled(dep->signaler));
483 GEM_BUG_ON(!list_empty(&dep->dfs_link));
484
485 list_del(&dep->wait_link);
486 if (dep->flags & I915_DEPENDENCY_ALLOC)
487 i915_dependency_free(dep);
488 }
489
490
491 list_for_each_entry_safe(dep, tmp, &node->waiters_list, wait_link) {
492 GEM_BUG_ON(dep->signaler != node);
493 GEM_BUG_ON(!list_empty(&dep->dfs_link));
494
495 list_del(&dep->signal_link);
496 if (dep->flags & I915_DEPENDENCY_ALLOC)
497 i915_dependency_free(dep);
498 }
499
500 spin_unlock_irq(&schedule_lock);
501 }
502
503 static void i915_global_scheduler_shrink(void)
504 {
505 kmem_cache_shrink(global.slab_dependencies);
506 kmem_cache_shrink(global.slab_priorities);
507 }
508
509 static void i915_global_scheduler_exit(void)
510 {
511 kmem_cache_destroy(global.slab_dependencies);
512 kmem_cache_destroy(global.slab_priorities);
513 }
514
515 static struct i915_global_scheduler global = { {
516 .shrink = i915_global_scheduler_shrink,
517 .exit = i915_global_scheduler_exit,
518 } };
519
520 int __init i915_global_scheduler_init(void)
521 {
522 global.slab_dependencies = KMEM_CACHE(i915_dependency,
523 SLAB_HWCACHE_ALIGN);
524 if (!global.slab_dependencies)
525 return -ENOMEM;
526
527 global.slab_priorities = KMEM_CACHE(i915_priolist,
528 SLAB_HWCACHE_ALIGN);
529 if (!global.slab_priorities)
530 goto err_priorities;
531
532 i915_global_register(&global.base);
533 return 0;
534
535 err_priorities:
536 kmem_cache_destroy(global.slab_priorities);
537 return -ENOMEM;
538 }