1 /* $NetBSD: i915_request.h,v 1.4 2021/12/19 11:36:17 riastradh Exp $ */ 2 3 /* 4 * Copyright © 2008-2018 Intel Corporation 5 * 6 * Permission is hereby granted, free of charge, to any person obtaining a 7 * copy of this software and associated documentation files (the "Software"), 8 * to deal in the Software without restriction, including without limitation 9 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 10 * and/or sell copies of the Software, and to permit persons to whom the 11 * Software is furnished to do so, subject to the following conditions: 12 * 13 * The above copyright notice and this permission notice (including the next 14 * paragraph) shall be included in all copies or substantial portions of the 15 * Software. 16 * 17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 20 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 21 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 22 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS 23 * IN THE SOFTWARE. 24 * 25 */ 26 27 #ifndef I915_REQUEST_H 28 #define I915_REQUEST_H 29 30 #include <linux/dma-fence.h> 31 #include <linux/lockdep.h> 32 33 #include "gem/i915_gem_context_types.h" 34 #include "gt/intel_context_types.h" 35 #include "gt/intel_engine_types.h" 36 #include "gt/intel_timeline_types.h" 37 38 #include "i915_gem.h" 39 #include "i915_scheduler.h" 40 #include "i915_selftest.h" 41 #include "i915_sw_fence.h" 42 43 #include <uapi/drm/i915_drm.h> 44 45 struct drm_file; 46 struct drm_i915_gem_object; 47 struct i915_request; 48 49 struct i915_capture_list { 50 struct i915_capture_list *next; 51 struct i915_vma *vma; 52 }; 53 54 #define RQ_TRACE(rq, fmt, ...) do { \ 55 const struct i915_request *rq__ = (rq); \ 56 ENGINE_TRACE(rq__->engine, "fence %llx:%lld, current %d " fmt, \ 57 rq__->fence.context, rq__->fence.seqno, \ 58 hwsp_seqno(rq__), ##__VA_ARGS__); \ 59 } while (0) 60 61 enum { 62 /* 63 * I915_FENCE_FLAG_ACTIVE - this request is currently submitted to HW. 64 * 65 * Set by __i915_request_submit() on handing over to HW, and cleared 66 * by __i915_request_unsubmit() if we preempt this request. 67 * 68 * Finally cleared for consistency on retiring the request, when 69 * we know the HW is no longer running this request. 70 * 71 * See i915_request_is_active() 72 */ 73 I915_FENCE_FLAG_ACTIVE = DMA_FENCE_FLAG_USER_BITS, 74 75 /* 76 * I915_FENCE_FLAG_PQUEUE - this request is ready for execution 77 * 78 * Using the scheduler, when a request is ready for execution it is put 79 * into the priority queue, and removed from that queue when transferred 80 * to the HW runlists. We want to track its membership within the 81 * priority queue so that we can easily check before rescheduling. 82 * 83 * See i915_request_in_priority_queue() 84 */ 85 I915_FENCE_FLAG_PQUEUE, 86 87 /* 88 * I915_FENCE_FLAG_SIGNAL - this request is currently on signal_list 89 * 90 * Internal bookkeeping used by the breadcrumb code to track when 91 * a request is on the various signal_list. 92 */ 93 I915_FENCE_FLAG_SIGNAL, 94 95 /* 96 * I915_FENCE_FLAG_HOLD - this request is currently on hold 97 * 98 * This request has been suspended, pending an ongoing investigation. 99 */ 100 I915_FENCE_FLAG_HOLD, 101 102 /* 103 * I915_FENCE_FLAG_NOPREEMPT - this request should not be preempted 104 * 105 * The execution of some requests should not be interrupted. This is 106 * a sensitive operation as it makes the request super important, 107 * blocking other higher priority work. Abuse of this flag will 108 * lead to quality of service issues. 109 */ 110 I915_FENCE_FLAG_NOPREEMPT, 111 112 /* 113 * I915_FENCE_FLAG_SENTINEL - this request should be last in the queue 114 * 115 * A high priority sentinel request may be submitted to clear the 116 * submission queue. As it will be the only request in-flight, upon 117 * execution all other active requests will have been preempted and 118 * unsubmitted. This preemptive pulse is used to re-evaluate the 119 * in-flight requests, particularly in cases where an active context 120 * is banned and those active requests need to be cancelled. 121 */ 122 I915_FENCE_FLAG_SENTINEL, 123 124 /* 125 * I915_FENCE_FLAG_BOOST - upclock the gpu for this request 126 * 127 * Some requests are more important than others! In particular, a 128 * request that the user is waiting on is typically required for 129 * interactive latency, for which we want to minimise by upclocking 130 * the GPU. Here we track such boost requests on a per-request basis. 131 */ 132 I915_FENCE_FLAG_BOOST, 133 }; 134 135 /** 136 * Request queue structure. 137 * 138 * The request queue allows us to note sequence numbers that have been emitted 139 * and may be associated with active buffers to be retired. 140 * 141 * By keeping this list, we can avoid having to do questionable sequence 142 * number comparisons on buffer last_read|write_seqno. It also allows an 143 * emission time to be associated with the request for tracking how far ahead 144 * of the GPU the submission is. 145 * 146 * When modifying this structure be very aware that we perform a lockless 147 * RCU lookup of it that may race against reallocation of the struct 148 * from the slab freelist. We intentionally do not zero the structure on 149 * allocation so that the lookup can use the dangling pointers (and is 150 * cogniscent that those pointers may be wrong). Instead, everything that 151 * needs to be initialised must be done so explicitly. 152 * 153 * The requests are reference counted. 154 */ 155 struct i915_request { 156 struct dma_fence fence; 157 spinlock_t lock; 158 159 /** On Which ring this request was generated */ 160 struct drm_i915_private *i915; 161 162 /** 163 * Context and ring buffer related to this request 164 * Contexts are refcounted, so when this request is associated with a 165 * context, we must increment the context's refcount, to guarantee that 166 * it persists while any request is linked to it. Requests themselves 167 * are also refcounted, so the request will only be freed when the last 168 * reference to it is dismissed, and the code in 169 * i915_request_free() will then decrement the refcount on the 170 * context. 171 */ 172 struct intel_engine_cs *engine; 173 struct intel_context *context; 174 struct intel_ring *ring; 175 struct intel_timeline __rcu *timeline; 176 struct list_head signal_link; 177 178 /* 179 * The rcu epoch of when this request was allocated. Used to judiciously 180 * apply backpressure on future allocations to ensure that under 181 * mempressure there is sufficient RCU ticks for us to reclaim our 182 * RCU protected slabs. 183 */ 184 unsigned long rcustate; 185 186 /* 187 * We pin the timeline->mutex while constructing the request to 188 * ensure that no caller accidentally drops it during construction. 189 * The timeline->mutex must be held to ensure that only this caller 190 * can use the ring and manipulate the associated timeline during 191 * construction. 192 */ 193 struct pin_cookie cookie; 194 195 /* 196 * Fences for the various phases in the request's lifetime. 197 * 198 * The submit fence is used to await upon all of the request's 199 * dependencies. When it is signaled, the request is ready to run. 200 * It is used by the driver to then queue the request for execution. 201 */ 202 struct i915_sw_fence submit; 203 union { 204 #ifdef __NetBSD__ /* XXX */ 205 struct i915_sw_fence_waiter submitq; 206 #else 207 wait_queue_entry_t submitq; 208 #endif 209 struct i915_sw_dma_fence_cb dmaq; 210 struct i915_request_duration_cb { 211 struct dma_fence_cb cb; 212 ktime_t emitted; 213 } duration; 214 }; 215 struct list_head execute_cb; 216 struct i915_sw_fence semaphore; 217 218 /* 219 * A list of everyone we wait upon, and everyone who waits upon us. 220 * Even though we will not be submitted to the hardware before the 221 * submit fence is signaled (it waits for all external events as well 222 * as our own requests), the scheduler still needs to know the 223 * dependency tree for the lifetime of the request (from execbuf 224 * to retirement), i.e. bidirectional dependency information for the 225 * request not tied to individual fences. 226 */ 227 struct i915_sched_node sched; 228 struct i915_dependency dep; 229 intel_engine_mask_t execution_mask; 230 231 /* 232 * A convenience pointer to the current breadcrumb value stored in 233 * the HW status page (or our timeline's local equivalent). The full 234 * path would be rq->hw_context->ring->timeline->hwsp_seqno. 235 */ 236 const u32 *hwsp_seqno; 237 238 /* 239 * If we need to access the timeline's seqno for this request in 240 * another request, we need to keep a read reference to this associated 241 * cacheline, so that we do not free and recycle it before the foreign 242 * observers have completed. Hence, we keep a pointer to the cacheline 243 * inside the timeline's HWSP vma, but it is only valid while this 244 * request has not completed and guarded by the timeline mutex. 245 */ 246 struct intel_timeline_cacheline __rcu *hwsp_cacheline; 247 248 /** Position in the ring of the start of the request */ 249 u32 head; 250 251 /** Position in the ring of the start of the user packets */ 252 u32 infix; 253 254 /** 255 * Position in the ring of the start of the postfix. 256 * This is required to calculate the maximum available ring space 257 * without overwriting the postfix. 258 */ 259 u32 postfix; 260 261 /** Position in the ring of the end of the whole request */ 262 u32 tail; 263 264 /** Position in the ring of the end of any workarounds after the tail */ 265 u32 wa_tail; 266 267 /** Preallocate space in the ring for the emitting the request */ 268 u32 reserved_space; 269 270 /** Batch buffer related to this request if any (used for 271 * error state dump only). 272 */ 273 struct i915_vma *batch; 274 /** 275 * Additional buffers requested by userspace to be captured upon 276 * a GPU hang. The vma/obj on this list are protected by their 277 * active reference - all objects on this list must also be 278 * on the active_list (of their final request). 279 */ 280 struct i915_capture_list *capture_list; 281 282 /** Time at which this request was emitted, in jiffies. */ 283 unsigned long emitted_jiffies; 284 285 /** timeline->request entry for this request */ 286 struct list_head link; 287 288 struct drm_i915_file_private *file_priv; 289 /** file_priv list entry for this request */ 290 struct list_head client_link; 291 292 I915_SELFTEST_DECLARE(struct { 293 struct list_head link; 294 unsigned long delay; 295 } mock;) 296 }; 297 298 #define I915_FENCE_GFP (GFP_KERNEL | __GFP_RETRY_MAYFAIL | __GFP_NOWARN) 299 300 extern const struct dma_fence_ops i915_fence_ops; 301 302 static inline bool dma_fence_is_i915(const struct dma_fence *fence) 303 { 304 return fence->ops == &i915_fence_ops; 305 } 306 307 struct i915_request * __must_check 308 __i915_request_create(struct intel_context *ce, gfp_t gfp); 309 struct i915_request * __must_check 310 i915_request_create(struct intel_context *ce); 311 312 struct i915_request *__i915_request_commit(struct i915_request *request); 313 void __i915_request_queue(struct i915_request *rq, 314 const struct i915_sched_attr *attr); 315 316 bool i915_request_retire(struct i915_request *rq); 317 void i915_request_retire_upto(struct i915_request *rq); 318 319 static inline struct i915_request * 320 to_request(struct dma_fence *fence) 321 { 322 /* We assume that NULL fence/request are interoperable */ 323 BUILD_BUG_ON(offsetof(struct i915_request, fence) != 0); 324 GEM_BUG_ON(fence && !dma_fence_is_i915(fence)); 325 return container_of(fence, struct i915_request, fence); 326 } 327 328 static inline struct i915_request * 329 i915_request_get(struct i915_request *rq) 330 { 331 return to_request(dma_fence_get(&rq->fence)); 332 } 333 334 static inline struct i915_request * 335 i915_request_get_rcu(struct i915_request *rq) 336 { 337 return to_request(dma_fence_get_rcu(&rq->fence)); 338 } 339 340 static inline void 341 i915_request_put(struct i915_request *rq) 342 { 343 dma_fence_put(&rq->fence); 344 } 345 346 int i915_request_await_object(struct i915_request *to, 347 struct drm_i915_gem_object *obj, 348 bool write); 349 int i915_request_await_dma_fence(struct i915_request *rq, 350 struct dma_fence *fence); 351 int i915_request_await_execution(struct i915_request *rq, 352 struct dma_fence *fence, 353 void (*hook)(struct i915_request *rq, 354 struct dma_fence *signal)); 355 356 void i915_request_add(struct i915_request *rq); 357 358 bool __i915_request_submit(struct i915_request *request); 359 void i915_request_submit(struct i915_request *request); 360 361 void i915_request_skip(struct i915_request *request, int error); 362 363 void __i915_request_unsubmit(struct i915_request *request); 364 void i915_request_unsubmit(struct i915_request *request); 365 366 /* Note: part of the intel_breadcrumbs family */ 367 bool i915_request_enable_breadcrumb(struct i915_request *request); 368 void i915_request_cancel_breadcrumb(struct i915_request *request); 369 370 long i915_request_wait(struct i915_request *rq, 371 unsigned int flags, 372 long timeout) 373 __attribute__((nonnull(1))); 374 #define I915_WAIT_INTERRUPTIBLE BIT(0) 375 #define I915_WAIT_PRIORITY BIT(1) /* small priority bump for the request */ 376 #define I915_WAIT_ALL BIT(2) /* used by i915_gem_object_wait() */ 377 378 static inline bool i915_request_signaled(const struct i915_request *rq) 379 { 380 /* The request may live longer than its HWSP, so check flags first! */ 381 return test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &rq->fence.flags); 382 } 383 384 static inline bool i915_request_is_active(const struct i915_request *rq) 385 { 386 return test_bit(I915_FENCE_FLAG_ACTIVE, &rq->fence.flags); 387 } 388 389 static inline bool i915_request_in_priority_queue(const struct i915_request *rq) 390 { 391 return test_bit(I915_FENCE_FLAG_PQUEUE, &rq->fence.flags); 392 } 393 394 /** 395 * Returns true if seq1 is later than seq2. 396 */ 397 static inline bool i915_seqno_passed(u32 seq1, u32 seq2) 398 { 399 return (s32)(seq1 - seq2) >= 0; 400 } 401 402 static inline u32 __hwsp_seqno(const struct i915_request *rq) 403 { 404 return READ_ONCE(*rq->hwsp_seqno); 405 } 406 407 /** 408 * hwsp_seqno - the current breadcrumb value in the HW status page 409 * @rq: the request, to chase the relevant HW status page 410 * 411 * The emphasis in naming here is that hwsp_seqno() is not a property of the 412 * request, but an indication of the current HW state (associated with this 413 * request). Its value will change as the GPU executes more requests. 414 * 415 * Returns the current breadcrumb value in the associated HW status page (or 416 * the local timeline's equivalent) for this request. The request itself 417 * has the associated breadcrumb value of rq->fence.seqno, when the HW 418 * status page has that breadcrumb or later, this request is complete. 419 */ 420 static inline u32 hwsp_seqno(const struct i915_request *rq) 421 { 422 u32 seqno; 423 424 rcu_read_lock(); /* the HWSP may be freed at runtime */ 425 seqno = __hwsp_seqno(rq); 426 rcu_read_unlock(); 427 428 return seqno; 429 } 430 431 static inline bool __i915_request_has_started(const struct i915_request *rq) 432 { 433 return i915_seqno_passed(hwsp_seqno(rq), rq->fence.seqno - 1); 434 } 435 436 /** 437 * i915_request_started - check if the request has begun being executed 438 * @rq: the request 439 * 440 * If the timeline is not using initial breadcrumbs, a request is 441 * considered started if the previous request on its timeline (i.e. 442 * context) has been signaled. 443 * 444 * If the timeline is using semaphores, it will also be emitting an 445 * "initial breadcrumb" after the semaphores are complete and just before 446 * it began executing the user payload. A request can therefore be active 447 * on the HW and not yet started as it is still busywaiting on its 448 * dependencies (via HW semaphores). 449 * 450 * If the request has started, its dependencies will have been signaled 451 * (either by fences or by semaphores) and it will have begun processing 452 * the user payload. 453 * 454 * However, even if a request has started, it may have been preempted and 455 * so no longer active, or it may have already completed. 456 * 457 * See also i915_request_is_active(). 458 * 459 * Returns true if the request has begun executing the user payload, or 460 * has completed: 461 */ 462 static inline bool i915_request_started(const struct i915_request *rq) 463 { 464 if (i915_request_signaled(rq)) 465 return true; 466 467 /* Remember: started but may have since been preempted! */ 468 return __i915_request_has_started(rq); 469 } 470 471 /** 472 * i915_request_is_running - check if the request may actually be executing 473 * @rq: the request 474 * 475 * Returns true if the request is currently submitted to hardware, has passed 476 * its start point (i.e. the context is setup and not busywaiting). Note that 477 * it may no longer be running by the time the function returns! 478 */ 479 static inline bool i915_request_is_running(const struct i915_request *rq) 480 { 481 if (!i915_request_is_active(rq)) 482 return false; 483 484 return __i915_request_has_started(rq); 485 } 486 487 /** 488 * i915_request_is_running - check if the request is ready for execution 489 * @rq: the request 490 * 491 * Upon construction, the request is instructed to wait upon various 492 * signals before it is ready to be executed by the HW. That is, we do 493 * not want to start execution and read data before it is written. In practice, 494 * this is controlled with a mixture of interrupts and semaphores. Once 495 * the submit fence is completed, the backend scheduler will place the 496 * request into its queue and from there submit it for execution. So we 497 * can detect when a request is eligible for execution (and is under control 498 * of the scheduler) by querying where it is in any of the scheduler's lists. 499 * 500 * Returns true if the request is ready for execution (it may be inflight), 501 * false otherwise. 502 */ 503 static inline bool i915_request_is_ready(const struct i915_request *rq) 504 { 505 return !list_empty(&rq->sched.link); 506 } 507 508 static inline bool i915_request_completed(const struct i915_request *rq) 509 { 510 if (i915_request_signaled(rq)) 511 return true; 512 513 return i915_seqno_passed(hwsp_seqno(rq), rq->fence.seqno); 514 } 515 516 static inline void i915_request_mark_complete(struct i915_request *rq) 517 { 518 rq->hwsp_seqno = (u32 *)&rq->fence.seqno; /* decouple from HWSP */ 519 } 520 521 static inline bool i915_request_has_waitboost(const struct i915_request *rq) 522 { 523 return test_bit(I915_FENCE_FLAG_BOOST, &rq->fence.flags); 524 } 525 526 static inline bool i915_request_has_nopreempt(const struct i915_request *rq) 527 { 528 /* Preemption should only be disabled very rarely */ 529 return unlikely(test_bit(I915_FENCE_FLAG_NOPREEMPT, &rq->fence.flags)); 530 } 531 532 static inline bool i915_request_has_sentinel(const struct i915_request *rq) 533 { 534 return unlikely(test_bit(I915_FENCE_FLAG_SENTINEL, &rq->fence.flags)); 535 } 536 537 static inline bool i915_request_on_hold(const struct i915_request *rq) 538 { 539 return unlikely(test_bit(I915_FENCE_FLAG_HOLD, &rq->fence.flags)); 540 } 541 542 static inline void i915_request_set_hold(struct i915_request *rq) 543 { 544 set_bit(I915_FENCE_FLAG_HOLD, &rq->fence.flags); 545 } 546 547 static inline void i915_request_clear_hold(struct i915_request *rq) 548 { 549 clear_bit(I915_FENCE_FLAG_HOLD, &rq->fence.flags); 550 } 551 552 static inline struct intel_timeline * 553 i915_request_timeline(struct i915_request *rq) 554 { 555 /* Valid only while the request is being constructed (or retired). */ 556 return rcu_dereference_protected(rq->timeline, 557 lockdep_is_held(&rcu_access_pointer(rq->timeline)->mutex)); 558 } 559 560 static inline struct i915_gem_context * 561 i915_request_gem_context(struct i915_request *rq) 562 { 563 /* Valid only while the request is being constructed (or retired). */ 564 return rcu_dereference_protected(rq->context->gem_context, true); 565 } 566 567 static inline struct intel_timeline * 568 i915_request_active_timeline(struct i915_request *rq) 569 { 570 /* 571 * When in use during submission, we are protected by a guarantee that 572 * the context/timeline is pinned and must remain pinned until after 573 * this submission. 574 */ 575 return rcu_dereference_protected(rq->timeline, 576 lockdep_is_held(&rq->engine->active.lock)); 577 } 578 579 #endif /* I915_REQUEST_H */ 580