1 /* 2 * Copyright © 2008-2018 Intel Corporation 3 * 4 * Permission is hereby granted, free of charge, to any person obtaining a 5 * copy of this software and associated documentation files (the "Software"), 6 * to deal in the Software without restriction, including without limitation 7 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 8 * and/or sell copies of the Software, and to permit persons to whom the 9 * Software is furnished to do so, subject to the following conditions: 10 * 11 * The above copyright notice and this permission notice (including the next 12 * paragraph) shall be included in all copies or substantial portions of the 13 * Software. 14 * 15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS 21 * IN THE SOFTWARE. 22 * 23 */ 24 25 #ifndef I915_REQUEST_H 26 #define I915_REQUEST_H 27 28 #include <linux/dma-fence.h> 29 #include <linux/irq_work.h> 30 #include <linux/lockdep.h> 31 32 #include "gem/i915_gem_context_types.h" 33 #include "gt/intel_context_types.h" 34 #include "gt/intel_engine_types.h" 35 #include "gt/intel_timeline_types.h" 36 37 #include "i915_gem.h" 38 #include "i915_scheduler.h" 39 #include "i915_selftest.h" 40 #include "i915_sw_fence.h" 41 42 #include <uapi/drm/i915_drm.h> 43 44 struct drm_file; 45 struct drm_i915_gem_object; 46 struct i915_request; 47 48 struct i915_capture_list { 49 struct i915_capture_list *next; 50 struct i915_vma *vma; 51 }; 52 53 #define RQ_TRACE(rq, fmt, ...) do { \ 54 const struct i915_request *rq__ = (rq); \ 55 ENGINE_TRACE(rq__->engine, "fence %llx:%lld, current %d " fmt, \ 56 rq__->fence.context, rq__->fence.seqno, \ 57 hwsp_seqno(rq__), ##__VA_ARGS__); \ 58 } while (0) 59 60 enum { 61 /* 62 * I915_FENCE_FLAG_ACTIVE - this request is currently submitted to HW. 63 * 64 * Set by __i915_request_submit() on handing over to HW, and cleared 65 * by __i915_request_unsubmit() if we preempt this request. 66 * 67 * Finally cleared for consistency on retiring the request, when 68 * we know the HW is no longer running this request. 69 * 70 * See i915_request_is_active() 71 */ 72 I915_FENCE_FLAG_ACTIVE = DMA_FENCE_FLAG_USER_BITS, 73 74 /* 75 * I915_FENCE_FLAG_PQUEUE - this request is ready for execution 76 * 77 * Using the scheduler, when a request is ready for execution it is put 78 * into the priority queue, and removed from that queue when transferred 79 * to the HW runlists. We want to track its membership within the 80 * priority queue so that we can easily check before rescheduling. 81 * 82 * See i915_request_in_priority_queue() 83 */ 84 I915_FENCE_FLAG_PQUEUE, 85 86 /* 87 * I915_FENCE_FLAG_HOLD - this request is currently on hold 88 * 89 * This request has been suspended, pending an ongoing investigation. 90 */ 91 I915_FENCE_FLAG_HOLD, 92 93 /* 94 * I915_FENCE_FLAG_INITIAL_BREADCRUMB - this request has the initial 95 * breadcrumb that marks the end of semaphore waits and start of the 96 * user payload. 97 */ 98 I915_FENCE_FLAG_INITIAL_BREADCRUMB, 99 100 /* 101 * I915_FENCE_FLAG_SIGNAL - this request is currently on signal_list 102 * 103 * Internal bookkeeping used by the breadcrumb code to track when 104 * a request is on the various signal_list. 105 */ 106 I915_FENCE_FLAG_SIGNAL, 107 108 /* 109 * I915_FENCE_FLAG_NOPREEMPT - this request should not be preempted 110 * 111 * The execution of some requests should not be interrupted. This is 112 * a sensitive operation as it makes the request super important, 113 * blocking other higher priority work. Abuse of this flag will 114 * lead to quality of service issues. 115 */ 116 I915_FENCE_FLAG_NOPREEMPT, 117 118 /* 119 * I915_FENCE_FLAG_SENTINEL - this request should be last in the queue 120 * 121 * A high priority sentinel request may be submitted to clear the 122 * submission queue. As it will be the only request in-flight, upon 123 * execution all other active requests will have been preempted and 124 * unsubmitted. This preemptive pulse is used to re-evaluate the 125 * in-flight requests, particularly in cases where an active context 126 * is banned and those active requests need to be cancelled. 127 */ 128 I915_FENCE_FLAG_SENTINEL, 129 130 /* 131 * I915_FENCE_FLAG_BOOST - upclock the gpu for this request 132 * 133 * Some requests are more important than others! In particular, a 134 * request that the user is waiting on is typically required for 135 * interactive latency, for which we want to minimise by upclocking 136 * the GPU. Here we track such boost requests on a per-request basis. 137 */ 138 I915_FENCE_FLAG_BOOST, 139 }; 140 141 /** 142 * Request queue structure. 143 * 144 * The request queue allows us to note sequence numbers that have been emitted 145 * and may be associated with active buffers to be retired. 146 * 147 * By keeping this list, we can avoid having to do questionable sequence 148 * number comparisons on buffer last_read|write_seqno. It also allows an 149 * emission time to be associated with the request for tracking how far ahead 150 * of the GPU the submission is. 151 * 152 * When modifying this structure be very aware that we perform a lockless 153 * RCU lookup of it that may race against reallocation of the struct 154 * from the slab freelist. We intentionally do not zero the structure on 155 * allocation so that the lookup can use the dangling pointers (and is 156 * cogniscent that those pointers may be wrong). Instead, everything that 157 * needs to be initialised must be done so explicitly. 158 * 159 * The requests are reference counted. 160 */ 161 struct i915_request { 162 struct dma_fence fence; 163 spinlock_t lock; 164 165 /** 166 * Context and ring buffer related to this request 167 * Contexts are refcounted, so when this request is associated with a 168 * context, we must increment the context's refcount, to guarantee that 169 * it persists while any request is linked to it. Requests themselves 170 * are also refcounted, so the request will only be freed when the last 171 * reference to it is dismissed, and the code in 172 * i915_request_free() will then decrement the refcount on the 173 * context. 174 */ 175 struct intel_engine_cs *engine; 176 struct intel_context *context; 177 struct intel_ring *ring; 178 struct intel_timeline __rcu *timeline; 179 180 union { 181 struct list_head signal_link; 182 struct llist_node signal_node; 183 }; 184 185 /* 186 * The rcu epoch of when this request was allocated. Used to judiciously 187 * apply backpressure on future allocations to ensure that under 188 * mempressure there is sufficient RCU ticks for us to reclaim our 189 * RCU protected slabs. 190 */ 191 unsigned long rcustate; 192 193 /* 194 * We pin the timeline->mutex while constructing the request to 195 * ensure that no caller accidentally drops it during construction. 196 * The timeline->mutex must be held to ensure that only this caller 197 * can use the ring and manipulate the associated timeline during 198 * construction. 199 */ 200 struct pin_cookie cookie; 201 202 /* 203 * Fences for the various phases in the request's lifetime. 204 * 205 * The submit fence is used to await upon all of the request's 206 * dependencies. When it is signaled, the request is ready to run. 207 * It is used by the driver to then queue the request for execution. 208 */ 209 struct i915_sw_fence submit; 210 union { 211 wait_queue_entry_t submitq; 212 struct i915_sw_dma_fence_cb dmaq; 213 struct i915_request_duration_cb { 214 struct dma_fence_cb cb; 215 ktime_t emitted; 216 } duration; 217 }; 218 struct llist_head execute_cb; 219 struct i915_sw_fence semaphore; 220 221 /* 222 * A list of everyone we wait upon, and everyone who waits upon us. 223 * Even though we will not be submitted to the hardware before the 224 * submit fence is signaled (it waits for all external events as well 225 * as our own requests), the scheduler still needs to know the 226 * dependency tree for the lifetime of the request (from execbuf 227 * to retirement), i.e. bidirectional dependency information for the 228 * request not tied to individual fences. 229 */ 230 struct i915_sched_node sched; 231 struct i915_dependency dep; 232 intel_engine_mask_t execution_mask; 233 234 /* 235 * A convenience pointer to the current breadcrumb value stored in 236 * the HW status page (or our timeline's local equivalent). The full 237 * path would be rq->hw_context->ring->timeline->hwsp_seqno. 238 */ 239 const u32 *hwsp_seqno; 240 241 /* 242 * If we need to access the timeline's seqno for this request in 243 * another request, we need to keep a read reference to this associated 244 * cacheline, so that we do not free and recycle it before the foreign 245 * observers have completed. Hence, we keep a pointer to the cacheline 246 * inside the timeline's HWSP vma, but it is only valid while this 247 * request has not completed and guarded by the timeline mutex. 248 */ 249 struct intel_timeline_cacheline __rcu *hwsp_cacheline; 250 251 /** Position in the ring of the start of the request */ 252 u32 head; 253 254 /** Position in the ring of the start of the user packets */ 255 u32 infix; 256 257 /** 258 * Position in the ring of the start of the postfix. 259 * This is required to calculate the maximum available ring space 260 * without overwriting the postfix. 261 */ 262 u32 postfix; 263 264 /** Position in the ring of the end of the whole request */ 265 u32 tail; 266 267 /** Position in the ring of the end of any workarounds after the tail */ 268 u32 wa_tail; 269 270 /** Preallocate space in the ring for the emitting the request */ 271 u32 reserved_space; 272 273 /** Batch buffer related to this request if any (used for 274 * error state dump only). 275 */ 276 struct i915_vma *batch; 277 /** 278 * Additional buffers requested by userspace to be captured upon 279 * a GPU hang. The vma/obj on this list are protected by their 280 * active reference - all objects on this list must also be 281 * on the active_list (of their final request). 282 */ 283 struct i915_capture_list *capture_list; 284 285 /** Time at which this request was emitted, in jiffies. */ 286 unsigned long emitted_jiffies; 287 288 /** timeline->request entry for this request */ 289 struct list_head link; 290 291 I915_SELFTEST_DECLARE(struct { 292 struct list_head link; 293 unsigned long delay; 294 } mock;) 295 }; 296 297 #define I915_FENCE_GFP (GFP_KERNEL | __GFP_RETRY_MAYFAIL | __GFP_NOWARN) 298 299 extern const struct dma_fence_ops i915_fence_ops; 300 301 static inline bool dma_fence_is_i915(const struct dma_fence *fence) 302 { 303 return fence->ops == &i915_fence_ops; 304 } 305 306 struct kmem_cache *i915_request_slab_cache(void); 307 308 struct i915_request * __must_check 309 __i915_request_create(struct intel_context *ce, gfp_t gfp); 310 struct i915_request * __must_check 311 i915_request_create(struct intel_context *ce); 312 313 void i915_request_set_error_once(struct i915_request *rq, int error); 314 void __i915_request_skip(struct i915_request *rq); 315 316 struct i915_request *__i915_request_commit(struct i915_request *request); 317 void __i915_request_queue(struct i915_request *rq, 318 const struct i915_sched_attr *attr); 319 320 bool i915_request_retire(struct i915_request *rq); 321 void i915_request_retire_upto(struct i915_request *rq); 322 323 static inline struct i915_request * 324 to_request(struct dma_fence *fence) 325 { 326 /* We assume that NULL fence/request are interoperable */ 327 BUILD_BUG_ON(offsetof(struct i915_request, fence) != 0); 328 GEM_BUG_ON(fence && !dma_fence_is_i915(fence)); 329 return container_of(fence, struct i915_request, fence); 330 } 331 332 static inline struct i915_request * 333 i915_request_get(struct i915_request *rq) 334 { 335 return to_request(dma_fence_get(&rq->fence)); 336 } 337 338 static inline struct i915_request * 339 i915_request_get_rcu(struct i915_request *rq) 340 { 341 return to_request(dma_fence_get_rcu(&rq->fence)); 342 } 343 344 static inline void 345 i915_request_put(struct i915_request *rq) 346 { 347 dma_fence_put(&rq->fence); 348 } 349 350 int i915_request_await_object(struct i915_request *to, 351 struct drm_i915_gem_object *obj, 352 bool write); 353 int i915_request_await_dma_fence(struct i915_request *rq, 354 struct dma_fence *fence); 355 int i915_request_await_execution(struct i915_request *rq, 356 struct dma_fence *fence, 357 void (*hook)(struct i915_request *rq, 358 struct dma_fence *signal)); 359 360 void i915_request_add(struct i915_request *rq); 361 362 bool __i915_request_submit(struct i915_request *request); 363 void i915_request_submit(struct i915_request *request); 364 365 void __i915_request_unsubmit(struct i915_request *request); 366 void i915_request_unsubmit(struct i915_request *request); 367 368 long i915_request_wait(struct i915_request *rq, 369 unsigned int flags, 370 long timeout) 371 __attribute__((nonnull(1))); 372 #define I915_WAIT_INTERRUPTIBLE BIT(0) 373 #define I915_WAIT_PRIORITY BIT(1) /* small priority bump for the request */ 374 #define I915_WAIT_ALL BIT(2) /* used by i915_gem_object_wait() */ 375 376 static inline bool i915_request_signaled(const struct i915_request *rq) 377 { 378 /* The request may live longer than its HWSP, so check flags first! */ 379 return test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &rq->fence.flags); 380 } 381 382 static inline bool i915_request_is_active(const struct i915_request *rq) 383 { 384 return test_bit(I915_FENCE_FLAG_ACTIVE, &rq->fence.flags); 385 } 386 387 static inline bool i915_request_in_priority_queue(const struct i915_request *rq) 388 { 389 return test_bit(I915_FENCE_FLAG_PQUEUE, &rq->fence.flags); 390 } 391 392 static inline bool 393 i915_request_has_initial_breadcrumb(const struct i915_request *rq) 394 { 395 return test_bit(I915_FENCE_FLAG_INITIAL_BREADCRUMB, &rq->fence.flags); 396 } 397 398 /** 399 * Returns true if seq1 is later than seq2. 400 */ 401 static inline bool i915_seqno_passed(u32 seq1, u32 seq2) 402 { 403 return (s32)(seq1 - seq2) >= 0; 404 } 405 406 static inline u32 __hwsp_seqno(const struct i915_request *rq) 407 { 408 const u32 *hwsp = READ_ONCE(rq->hwsp_seqno); 409 410 return READ_ONCE(*hwsp); 411 } 412 413 /** 414 * hwsp_seqno - the current breadcrumb value in the HW status page 415 * @rq: the request, to chase the relevant HW status page 416 * 417 * The emphasis in naming here is that hwsp_seqno() is not a property of the 418 * request, but an indication of the current HW state (associated with this 419 * request). Its value will change as the GPU executes more requests. 420 * 421 * Returns the current breadcrumb value in the associated HW status page (or 422 * the local timeline's equivalent) for this request. The request itself 423 * has the associated breadcrumb value of rq->fence.seqno, when the HW 424 * status page has that breadcrumb or later, this request is complete. 425 */ 426 static inline u32 hwsp_seqno(const struct i915_request *rq) 427 { 428 u32 seqno; 429 430 rcu_read_lock(); /* the HWSP may be freed at runtime */ 431 seqno = __hwsp_seqno(rq); 432 rcu_read_unlock(); 433 434 return seqno; 435 } 436 437 static inline bool __i915_request_has_started(const struct i915_request *rq) 438 { 439 return i915_seqno_passed(hwsp_seqno(rq), rq->fence.seqno - 1); 440 } 441 442 /** 443 * i915_request_started - check if the request has begun being executed 444 * @rq: the request 445 * 446 * If the timeline is not using initial breadcrumbs, a request is 447 * considered started if the previous request on its timeline (i.e. 448 * context) has been signaled. 449 * 450 * If the timeline is using semaphores, it will also be emitting an 451 * "initial breadcrumb" after the semaphores are complete and just before 452 * it began executing the user payload. A request can therefore be active 453 * on the HW and not yet started as it is still busywaiting on its 454 * dependencies (via HW semaphores). 455 * 456 * If the request has started, its dependencies will have been signaled 457 * (either by fences or by semaphores) and it will have begun processing 458 * the user payload. 459 * 460 * However, even if a request has started, it may have been preempted and 461 * so no longer active, or it may have already completed. 462 * 463 * See also i915_request_is_active(). 464 * 465 * Returns true if the request has begun executing the user payload, or 466 * has completed: 467 */ 468 static inline bool i915_request_started(const struct i915_request *rq) 469 { 470 if (i915_request_signaled(rq)) 471 return true; 472 473 /* Remember: started but may have since been preempted! */ 474 return __i915_request_has_started(rq); 475 } 476 477 /** 478 * i915_request_is_running - check if the request may actually be executing 479 * @rq: the request 480 * 481 * Returns true if the request is currently submitted to hardware, has passed 482 * its start point (i.e. the context is setup and not busywaiting). Note that 483 * it may no longer be running by the time the function returns! 484 */ 485 static inline bool i915_request_is_running(const struct i915_request *rq) 486 { 487 if (!i915_request_is_active(rq)) 488 return false; 489 490 return __i915_request_has_started(rq); 491 } 492 493 /** 494 * i915_request_is_ready - check if the request is ready for execution 495 * @rq: the request 496 * 497 * Upon construction, the request is instructed to wait upon various 498 * signals before it is ready to be executed by the HW. That is, we do 499 * not want to start execution and read data before it is written. In practice, 500 * this is controlled with a mixture of interrupts and semaphores. Once 501 * the submit fence is completed, the backend scheduler will place the 502 * request into its queue and from there submit it for execution. So we 503 * can detect when a request is eligible for execution (and is under control 504 * of the scheduler) by querying where it is in any of the scheduler's lists. 505 * 506 * Returns true if the request is ready for execution (it may be inflight), 507 * false otherwise. 508 */ 509 static inline bool i915_request_is_ready(const struct i915_request *rq) 510 { 511 return !list_empty(&rq->sched.link); 512 } 513 514 static inline bool i915_request_completed(const struct i915_request *rq) 515 { 516 if (i915_request_signaled(rq)) 517 return true; 518 519 return i915_seqno_passed(hwsp_seqno(rq), rq->fence.seqno); 520 } 521 522 static inline void i915_request_mark_complete(struct i915_request *rq) 523 { 524 WRITE_ONCE(rq->hwsp_seqno, /* decouple from HWSP */ 525 (u32 *)&rq->fence.seqno); 526 } 527 528 static inline bool i915_request_has_waitboost(const struct i915_request *rq) 529 { 530 return test_bit(I915_FENCE_FLAG_BOOST, &rq->fence.flags); 531 } 532 533 static inline bool i915_request_has_nopreempt(const struct i915_request *rq) 534 { 535 /* Preemption should only be disabled very rarely */ 536 return unlikely(test_bit(I915_FENCE_FLAG_NOPREEMPT, &rq->fence.flags)); 537 } 538 539 static inline bool i915_request_has_sentinel(const struct i915_request *rq) 540 { 541 return unlikely(test_bit(I915_FENCE_FLAG_SENTINEL, &rq->fence.flags)); 542 } 543 544 static inline bool i915_request_on_hold(const struct i915_request *rq) 545 { 546 return unlikely(test_bit(I915_FENCE_FLAG_HOLD, &rq->fence.flags)); 547 } 548 549 static inline void i915_request_set_hold(struct i915_request *rq) 550 { 551 set_bit(I915_FENCE_FLAG_HOLD, &rq->fence.flags); 552 } 553 554 static inline void i915_request_clear_hold(struct i915_request *rq) 555 { 556 clear_bit(I915_FENCE_FLAG_HOLD, &rq->fence.flags); 557 } 558 559 static inline struct intel_timeline * 560 i915_request_timeline(const struct i915_request *rq) 561 { 562 /* Valid only while the request is being constructed (or retired). */ 563 return rcu_dereference_protected(rq->timeline, 564 lockdep_is_held(&rcu_access_pointer(rq->timeline)->mutex)); 565 } 566 567 static inline struct i915_gem_context * 568 i915_request_gem_context(const struct i915_request *rq) 569 { 570 /* Valid only while the request is being constructed (or retired). */ 571 return rcu_dereference_protected(rq->context->gem_context, true); 572 } 573 574 static inline struct intel_timeline * 575 i915_request_active_timeline(const struct i915_request *rq) 576 { 577 /* 578 * When in use during submission, we are protected by a guarantee that 579 * the context/timeline is pinned and must remain pinned until after 580 * this submission. 581 */ 582 return rcu_dereference_protected(rq->timeline, 583 lockdep_is_held(&rq->engine->active.lock)); 584 } 585 586 #endif /* I915_REQUEST_H */ 587