1 /* 2 * QEMU aio implementation 3 * 4 * Copyright IBM, Corp. 2008 5 * 6 * Authors: 7 * Anthony Liguori <aliguori@us.ibm.com> 8 * 9 * This work is licensed under the terms of the GNU GPL, version 2. See 10 * the COPYING file in the top-level directory. 11 * 12 */ 13 14 #ifndef QEMU_AIO_H 15 #define QEMU_AIO_H 16 17 #ifdef CONFIG_LINUX_IO_URING 18 #include <liburing.h> 19 #endif 20 #include "qemu/coroutine-core.h" 21 #include "qemu/queue.h" 22 #include "qemu/event_notifier.h" 23 #include "qemu/thread.h" 24 #include "qemu/timer.h" 25 #include "block/graph-lock.h" 26 #include "hw/qdev-core.h" 27 28 29 typedef struct BlockAIOCB BlockAIOCB; 30 typedef void BlockCompletionFunc(void *opaque, int ret); 31 32 typedef struct AIOCBInfo { 33 void (*cancel_async)(BlockAIOCB *acb); 34 size_t aiocb_size; 35 } AIOCBInfo; 36 37 struct BlockAIOCB { 38 const AIOCBInfo *aiocb_info; 39 BlockDriverState *bs; 40 BlockCompletionFunc *cb; 41 void *opaque; 42 int refcnt; 43 }; 44 45 void *qemu_aio_get(const AIOCBInfo *aiocb_info, BlockDriverState *bs, 46 BlockCompletionFunc *cb, void *opaque); 47 void qemu_aio_unref(void *p); 48 void qemu_aio_ref(void *p); 49 50 typedef struct AioHandler AioHandler; 51 typedef QLIST_HEAD(, AioHandler) AioHandlerList; 52 typedef void QEMUBHFunc(void *opaque); 53 typedef bool AioPollFn(void *opaque); 54 typedef void IOHandler(void *opaque); 55 56 struct ThreadPool; 57 struct LinuxAioState; 58 struct LuringState; 59 60 /* Is polling disabled? */ 61 bool aio_poll_disabled(AioContext *ctx); 62 63 /* Callbacks for file descriptor monitoring implementations */ 64 typedef struct { 65 /* 66 * update: 67 * @ctx: the AioContext 68 * @old_node: the existing handler or NULL if this file descriptor is being 69 * monitored for the first time 70 * @new_node: the new handler or NULL if this file descriptor is being 71 * removed 72 * 73 * Add/remove/modify a monitored file descriptor. 74 * 75 * Called with ctx->list_lock acquired. 76 */ 77 void (*update)(AioContext *ctx, AioHandler *old_node, AioHandler *new_node); 78 79 /* 80 * wait: 81 * @ctx: the AioContext 82 * @ready_list: list for handlers that become ready 83 * @timeout: maximum duration to wait, in nanoseconds 84 * 85 * Wait for file descriptors to become ready and place them on ready_list. 86 * 87 * Called with ctx->list_lock incremented but not locked. 88 * 89 * Returns: number of ready file descriptors. 90 */ 91 int (*wait)(AioContext *ctx, AioHandlerList *ready_list, int64_t timeout); 92 93 /* 94 * need_wait: 95 * @ctx: the AioContext 96 * 97 * Tell aio_poll() when to stop userspace polling early because ->wait() 98 * has fds ready. 99 * 100 * File descriptor monitoring implementations that cannot poll fd readiness 101 * from userspace should use aio_poll_disabled() here. This ensures that 102 * file descriptors are not starved by handlers that frequently make 103 * progress via userspace polling. 104 * 105 * Returns: true if ->wait() should be called, false otherwise. 106 */ 107 bool (*need_wait)(AioContext *ctx); 108 } FDMonOps; 109 110 /* 111 * Each aio_bh_poll() call carves off a slice of the BH list, so that newly 112 * scheduled BHs are not processed until the next aio_bh_poll() call. All 113 * active aio_bh_poll() calls chain their slices together in a list, so that 114 * nested aio_bh_poll() calls process all scheduled bottom halves. 115 */ 116 typedef QSLIST_HEAD(, QEMUBH) BHList; 117 typedef struct BHListSlice BHListSlice; 118 struct BHListSlice { 119 BHList bh_list; 120 QSIMPLEQ_ENTRY(BHListSlice) next; 121 }; 122 123 typedef QSLIST_HEAD(, AioHandler) AioHandlerSList; 124 125 struct AioContext { 126 GSource source; 127 128 /* Used by AioContext users to protect from multi-threaded access. */ 129 QemuRecMutex lock; 130 131 /* 132 * Keep track of readers and writers of the block layer graph. 133 * This is essential to avoid performing additions and removal 134 * of nodes and edges from block graph while some 135 * other thread is traversing it. 136 */ 137 BdrvGraphRWlock *bdrv_graph; 138 139 /* The list of registered AIO handlers. Protected by ctx->list_lock. */ 140 AioHandlerList aio_handlers; 141 142 /* The list of AIO handlers to be deleted. Protected by ctx->list_lock. */ 143 AioHandlerList deleted_aio_handlers; 144 145 /* Used to avoid unnecessary event_notifier_set calls in aio_notify; 146 * only written from the AioContext home thread, or under the BQL in 147 * the case of the main AioContext. However, it is read from any 148 * thread so it is still accessed with atomic primitives. 149 * 150 * If this field is 0, everything (file descriptors, bottom halves, 151 * timers) will be re-evaluated before the next blocking poll() or 152 * io_uring wait; therefore, the event_notifier_set call can be 153 * skipped. If it is non-zero, you may need to wake up a concurrent 154 * aio_poll or the glib main event loop, making event_notifier_set 155 * necessary. 156 * 157 * Bit 0 is reserved for GSource usage of the AioContext, and is 1 158 * between a call to aio_ctx_prepare and the next call to aio_ctx_check. 159 * Bits 1-31 simply count the number of active calls to aio_poll 160 * that are in the prepare or poll phase. 161 * 162 * The GSource and aio_poll must use a different mechanism because 163 * there is no certainty that a call to GSource's prepare callback 164 * (via g_main_context_prepare) is indeed followed by check and 165 * dispatch. It's not clear whether this would be a bug, but let's 166 * play safe and allow it---it will just cause extra calls to 167 * event_notifier_set until the next call to dispatch. 168 * 169 * Instead, the aio_poll calls include both the prepare and the 170 * dispatch phase, hence a simple counter is enough for them. 171 */ 172 uint32_t notify_me; 173 174 /* A lock to protect between QEMUBH and AioHandler adders and deleter, 175 * and to ensure that no callbacks are removed while we're walking and 176 * dispatching them. 177 */ 178 QemuLockCnt list_lock; 179 180 /* Bottom Halves pending aio_bh_poll() processing */ 181 BHList bh_list; 182 183 /* Chained BH list slices for each nested aio_bh_poll() call */ 184 QSIMPLEQ_HEAD(, BHListSlice) bh_slice_list; 185 186 /* Used by aio_notify. 187 * 188 * "notified" is used to avoid expensive event_notifier_test_and_clear 189 * calls. When it is clear, the EventNotifier is clear, or one thread 190 * is going to clear "notified" before processing more events. False 191 * positives are possible, i.e. "notified" could be set even though the 192 * EventNotifier is clear. 193 * 194 * Note that event_notifier_set *cannot* be optimized the same way. For 195 * more information on the problem that would result, see "#ifdef BUG2" 196 * in the docs/aio_notify_accept.promela formal model. 197 */ 198 bool notified; 199 EventNotifier notifier; 200 201 QSLIST_HEAD(, Coroutine) scheduled_coroutines; 202 QEMUBH *co_schedule_bh; 203 204 int thread_pool_min; 205 int thread_pool_max; 206 /* Thread pool for performing work and receiving completion callbacks. 207 * Has its own locking. 208 */ 209 struct ThreadPool *thread_pool; 210 211 #ifdef CONFIG_LINUX_AIO 212 struct LinuxAioState *linux_aio; 213 #endif 214 #ifdef CONFIG_LINUX_IO_URING 215 struct LuringState *linux_io_uring; 216 217 /* State for file descriptor monitoring using Linux io_uring */ 218 struct io_uring fdmon_io_uring; 219 AioHandlerSList submit_list; 220 #endif 221 222 /* TimerLists for calling timers - one per clock type. Has its own 223 * locking. 224 */ 225 QEMUTimerListGroup tlg; 226 227 /* Number of AioHandlers without .io_poll() */ 228 int poll_disable_cnt; 229 230 /* Polling mode parameters */ 231 int64_t poll_ns; /* current polling time in nanoseconds */ 232 int64_t poll_max_ns; /* maximum polling time in nanoseconds */ 233 int64_t poll_grow; /* polling time growth factor */ 234 int64_t poll_shrink; /* polling time shrink factor */ 235 236 /* AIO engine parameters */ 237 int64_t aio_max_batch; /* maximum number of requests in a batch */ 238 239 /* 240 * List of handlers participating in userspace polling. Protected by 241 * ctx->list_lock. Iterated and modified mostly by the event loop thread 242 * from aio_poll() with ctx->list_lock incremented. aio_set_fd_handler() 243 * only touches the list to delete nodes if ctx->list_lock's count is zero. 244 */ 245 AioHandlerList poll_aio_handlers; 246 247 /* Are we in polling mode or monitoring file descriptors? */ 248 bool poll_started; 249 250 /* epoll(7) state used when built with CONFIG_EPOLL */ 251 int epollfd; 252 253 const FDMonOps *fdmon_ops; 254 }; 255 256 /** 257 * aio_context_new: Allocate a new AioContext. 258 * 259 * AioContext provide a mini event-loop that can be waited on synchronously. 260 * They also provide bottom halves, a service to execute a piece of code 261 * as soon as possible. 262 */ 263 AioContext *aio_context_new(Error **errp); 264 265 /** 266 * aio_context_ref: 267 * @ctx: The AioContext to operate on. 268 * 269 * Add a reference to an AioContext. 270 */ 271 void aio_context_ref(AioContext *ctx); 272 273 /** 274 * aio_context_unref: 275 * @ctx: The AioContext to operate on. 276 * 277 * Drop a reference to an AioContext. 278 */ 279 void aio_context_unref(AioContext *ctx); 280 281 /* Take ownership of the AioContext. If the AioContext will be shared between 282 * threads, and a thread does not want to be interrupted, it will have to 283 * take ownership around calls to aio_poll(). Otherwise, aio_poll() 284 * automatically takes care of calling aio_context_acquire and 285 * aio_context_release. 286 * 287 * Note that this is separate from bdrv_drained_begin/bdrv_drained_end. A 288 * thread still has to call those to avoid being interrupted by the guest. 289 * 290 * Bottom halves, timers and callbacks can be created or removed without 291 * acquiring the AioContext. 292 */ 293 void aio_context_acquire(AioContext *ctx); 294 295 /* Relinquish ownership of the AioContext. */ 296 void aio_context_release(AioContext *ctx); 297 298 /** 299 * aio_bh_schedule_oneshot_full: Allocate a new bottom half structure that will 300 * run only once and as soon as possible. 301 * 302 * @name: A human-readable identifier for debugging purposes. 303 */ 304 void aio_bh_schedule_oneshot_full(AioContext *ctx, QEMUBHFunc *cb, void *opaque, 305 const char *name); 306 307 /** 308 * aio_bh_schedule_oneshot: Allocate a new bottom half structure that will run 309 * only once and as soon as possible. 310 * 311 * A convenience wrapper for aio_bh_schedule_oneshot_full() that uses cb as the 312 * name string. 313 */ 314 #define aio_bh_schedule_oneshot(ctx, cb, opaque) \ 315 aio_bh_schedule_oneshot_full((ctx), (cb), (opaque), (stringify(cb))) 316 317 /** 318 * aio_bh_new_full: Allocate a new bottom half structure. 319 * 320 * Bottom halves are lightweight callbacks whose invocation is guaranteed 321 * to be wait-free, thread-safe and signal-safe. The #QEMUBH structure 322 * is opaque and must be allocated prior to its use. 323 * 324 * @name: A human-readable identifier for debugging purposes. 325 * @reentrancy_guard: A guard set when entering a cb to prevent 326 * device-reentrancy issues 327 */ 328 QEMUBH *aio_bh_new_full(AioContext *ctx, QEMUBHFunc *cb, void *opaque, 329 const char *name, MemReentrancyGuard *reentrancy_guard); 330 331 /** 332 * aio_bh_new: Allocate a new bottom half structure 333 * 334 * A convenience wrapper for aio_bh_new_full() that uses the cb as the name 335 * string. 336 */ 337 #define aio_bh_new(ctx, cb, opaque) \ 338 aio_bh_new_full((ctx), (cb), (opaque), (stringify(cb)), NULL) 339 340 /** 341 * aio_bh_new_guarded: Allocate a new bottom half structure with a 342 * reentrancy_guard 343 * 344 * A convenience wrapper for aio_bh_new_full() that uses the cb as the name 345 * string. 346 */ 347 #define aio_bh_new_guarded(ctx, cb, opaque, guard) \ 348 aio_bh_new_full((ctx), (cb), (opaque), (stringify(cb)), guard) 349 350 /** 351 * aio_notify: Force processing of pending events. 352 * 353 * Similar to signaling a condition variable, aio_notify forces 354 * aio_poll to exit, so that the next call will re-examine pending events. 355 * The caller of aio_notify will usually call aio_poll again very soon, 356 * or go through another iteration of the GLib main loop. Hence, aio_notify 357 * also has the side effect of recalculating the sets of file descriptors 358 * that the main loop waits for. 359 * 360 * Calling aio_notify is rarely necessary, because for example scheduling 361 * a bottom half calls it already. 362 */ 363 void aio_notify(AioContext *ctx); 364 365 /** 366 * aio_notify_accept: Acknowledge receiving an aio_notify. 367 * 368 * aio_notify() uses an EventNotifier in order to wake up a sleeping 369 * aio_poll() or g_main_context_iteration(). Calls to aio_notify() are 370 * usually rare, but the AioContext has to clear the EventNotifier on 371 * every aio_poll() or g_main_context_iteration() in order to avoid 372 * busy waiting. This event_notifier_test_and_clear() cannot be done 373 * using the usual aio_context_set_event_notifier(), because it must 374 * be done before processing all events (file descriptors, bottom halves, 375 * timers). 376 * 377 * aio_notify_accept() is an optimized event_notifier_test_and_clear() 378 * that is specific to an AioContext's notifier; it is used internally 379 * to clear the EventNotifier only if aio_notify() had been called. 380 */ 381 void aio_notify_accept(AioContext *ctx); 382 383 /** 384 * aio_bh_call: Executes callback function of the specified BH. 385 */ 386 void aio_bh_call(QEMUBH *bh); 387 388 /** 389 * aio_bh_poll: Poll bottom halves for an AioContext. 390 * 391 * These are internal functions used by the QEMU main loop. 392 * And notice that multiple occurrences of aio_bh_poll cannot 393 * be called concurrently 394 */ 395 int aio_bh_poll(AioContext *ctx); 396 397 /** 398 * qemu_bh_schedule: Schedule a bottom half. 399 * 400 * Scheduling a bottom half interrupts the main loop and causes the 401 * execution of the callback that was passed to qemu_bh_new. 402 * 403 * Bottom halves that are scheduled from a bottom half handler are instantly 404 * invoked. This can create an infinite loop if a bottom half handler 405 * schedules itself. 406 * 407 * @bh: The bottom half to be scheduled. 408 */ 409 void qemu_bh_schedule(QEMUBH *bh); 410 411 /** 412 * qemu_bh_cancel: Cancel execution of a bottom half. 413 * 414 * Canceling execution of a bottom half undoes the effect of calls to 415 * qemu_bh_schedule without freeing its resources yet. While cancellation 416 * itself is also wait-free and thread-safe, it can of course race with the 417 * loop that executes bottom halves unless you are holding the iothread 418 * mutex. This makes it mostly useless if you are not holding the mutex. 419 * 420 * @bh: The bottom half to be canceled. 421 */ 422 void qemu_bh_cancel(QEMUBH *bh); 423 424 /** 425 *qemu_bh_delete: Cancel execution of a bottom half and free its resources. 426 * 427 * Deleting a bottom half frees the memory that was allocated for it by 428 * qemu_bh_new. It also implies canceling the bottom half if it was 429 * scheduled. 430 * This func is async. The bottom half will do the delete action at the finial 431 * end. 432 * 433 * @bh: The bottom half to be deleted. 434 */ 435 void qemu_bh_delete(QEMUBH *bh); 436 437 /* Return whether there are any pending callbacks from the GSource 438 * attached to the AioContext, before g_poll is invoked. 439 * 440 * This is used internally in the implementation of the GSource. 441 */ 442 bool aio_prepare(AioContext *ctx); 443 444 /* Return whether there are any pending callbacks from the GSource 445 * attached to the AioContext, after g_poll is invoked. 446 * 447 * This is used internally in the implementation of the GSource. 448 */ 449 bool aio_pending(AioContext *ctx); 450 451 /* Dispatch any pending callbacks from the GSource attached to the AioContext. 452 * 453 * This is used internally in the implementation of the GSource. 454 */ 455 void aio_dispatch(AioContext *ctx); 456 457 /* Progress in completing AIO work to occur. This can issue new pending 458 * aio as a result of executing I/O completion or bh callbacks. 459 * 460 * Return whether any progress was made by executing AIO or bottom half 461 * handlers. If @blocking == true, this should always be true except 462 * if someone called aio_notify. 463 * 464 * If there are no pending bottom halves, but there are pending AIO 465 * operations, it may not be possible to make any progress without 466 * blocking. If @blocking is true, this function will wait until one 467 * or more AIO events have completed, to ensure something has moved 468 * before returning. 469 */ 470 bool no_coroutine_fn aio_poll(AioContext *ctx, bool blocking); 471 472 /* Register a file descriptor and associated callbacks. Behaves very similarly 473 * to qemu_set_fd_handler. Unlike qemu_set_fd_handler, these callbacks will 474 * be invoked when using aio_poll(). 475 * 476 * Code that invokes AIO completion functions should rely on this function 477 * instead of qemu_set_fd_handler[2]. 478 */ 479 void aio_set_fd_handler(AioContext *ctx, 480 int fd, 481 IOHandler *io_read, 482 IOHandler *io_write, 483 AioPollFn *io_poll, 484 IOHandler *io_poll_ready, 485 void *opaque); 486 487 /* Register an event notifier and associated callbacks. Behaves very similarly 488 * to event_notifier_set_handler. Unlike event_notifier_set_handler, these callbacks 489 * will be invoked when using aio_poll(). 490 * 491 * Code that invokes AIO completion functions should rely on this function 492 * instead of event_notifier_set_handler. 493 */ 494 void aio_set_event_notifier(AioContext *ctx, 495 EventNotifier *notifier, 496 EventNotifierHandler *io_read, 497 AioPollFn *io_poll, 498 EventNotifierHandler *io_poll_ready); 499 500 /* 501 * Set polling begin/end callbacks for an event notifier that has already been 502 * registered with aio_set_event_notifier. Do nothing if the event notifier is 503 * not registered. 504 * 505 * Note that if the io_poll_end() callback (or the entire notifier) is removed 506 * during polling, it will not be called, so an io_poll_begin() is not 507 * necessarily always followed by an io_poll_end(). 508 */ 509 void aio_set_event_notifier_poll(AioContext *ctx, 510 EventNotifier *notifier, 511 EventNotifierHandler *io_poll_begin, 512 EventNotifierHandler *io_poll_end); 513 514 /* Return a GSource that lets the main loop poll the file descriptors attached 515 * to this AioContext. 516 */ 517 GSource *aio_get_g_source(AioContext *ctx); 518 519 /* Return the ThreadPool bound to this AioContext */ 520 struct ThreadPool *aio_get_thread_pool(AioContext *ctx); 521 522 /* Setup the LinuxAioState bound to this AioContext */ 523 struct LinuxAioState *aio_setup_linux_aio(AioContext *ctx, Error **errp); 524 525 /* Return the LinuxAioState bound to this AioContext */ 526 struct LinuxAioState *aio_get_linux_aio(AioContext *ctx); 527 528 /* Setup the LuringState bound to this AioContext */ 529 struct LuringState *aio_setup_linux_io_uring(AioContext *ctx, Error **errp); 530 531 /* Return the LuringState bound to this AioContext */ 532 struct LuringState *aio_get_linux_io_uring(AioContext *ctx); 533 /** 534 * aio_timer_new_with_attrs: 535 * @ctx: the aio context 536 * @type: the clock type 537 * @scale: the scale 538 * @attributes: 0, or one to multiple OR'ed QEMU_TIMER_ATTR_<id> values 539 * to assign 540 * @cb: the callback to call on timer expiry 541 * @opaque: the opaque pointer to pass to the callback 542 * 543 * Allocate a new timer (with attributes) attached to the context @ctx. 544 * The function is responsible for memory allocation. 545 * 546 * The preferred interface is aio_timer_init or aio_timer_init_with_attrs. 547 * Use that unless you really need dynamic memory allocation. 548 * 549 * Returns: a pointer to the new timer 550 */ 551 static inline QEMUTimer *aio_timer_new_with_attrs(AioContext *ctx, 552 QEMUClockType type, 553 int scale, int attributes, 554 QEMUTimerCB *cb, void *opaque) 555 { 556 return timer_new_full(&ctx->tlg, type, scale, attributes, cb, opaque); 557 } 558 559 /** 560 * aio_timer_new: 561 * @ctx: the aio context 562 * @type: the clock type 563 * @scale: the scale 564 * @cb: the callback to call on timer expiry 565 * @opaque: the opaque pointer to pass to the callback 566 * 567 * Allocate a new timer attached to the context @ctx. 568 * See aio_timer_new_with_attrs for details. 569 * 570 * Returns: a pointer to the new timer 571 */ 572 static inline QEMUTimer *aio_timer_new(AioContext *ctx, QEMUClockType type, 573 int scale, 574 QEMUTimerCB *cb, void *opaque) 575 { 576 return timer_new_full(&ctx->tlg, type, scale, 0, cb, opaque); 577 } 578 579 /** 580 * aio_timer_init_with_attrs: 581 * @ctx: the aio context 582 * @ts: the timer 583 * @type: the clock type 584 * @scale: the scale 585 * @attributes: 0, or one to multiple OR'ed QEMU_TIMER_ATTR_<id> values 586 * to assign 587 * @cb: the callback to call on timer expiry 588 * @opaque: the opaque pointer to pass to the callback 589 * 590 * Initialise a new timer (with attributes) attached to the context @ctx. 591 * The caller is responsible for memory allocation. 592 */ 593 static inline void aio_timer_init_with_attrs(AioContext *ctx, 594 QEMUTimer *ts, QEMUClockType type, 595 int scale, int attributes, 596 QEMUTimerCB *cb, void *opaque) 597 { 598 timer_init_full(ts, &ctx->tlg, type, scale, attributes, cb, opaque); 599 } 600 601 /** 602 * aio_timer_init: 603 * @ctx: the aio context 604 * @ts: the timer 605 * @type: the clock type 606 * @scale: the scale 607 * @cb: the callback to call on timer expiry 608 * @opaque: the opaque pointer to pass to the callback 609 * 610 * Initialise a new timer attached to the context @ctx. 611 * See aio_timer_init_with_attrs for details. 612 */ 613 static inline void aio_timer_init(AioContext *ctx, 614 QEMUTimer *ts, QEMUClockType type, 615 int scale, 616 QEMUTimerCB *cb, void *opaque) 617 { 618 timer_init_full(ts, &ctx->tlg, type, scale, 0, cb, opaque); 619 } 620 621 /** 622 * aio_compute_timeout: 623 * @ctx: the aio context 624 * 625 * Compute the timeout that a blocking aio_poll should use. 626 */ 627 int64_t aio_compute_timeout(AioContext *ctx); 628 629 /** 630 * aio_co_schedule: 631 * @ctx: the aio context 632 * @co: the coroutine 633 * 634 * Start a coroutine on a remote AioContext. 635 * 636 * The coroutine must not be entered by anyone else while aio_co_schedule() 637 * is active. In addition the coroutine must have yielded unless ctx 638 * is the context in which the coroutine is running (i.e. the value of 639 * qemu_get_current_aio_context() from the coroutine itself). 640 */ 641 void aio_co_schedule(AioContext *ctx, Coroutine *co); 642 643 /** 644 * aio_co_reschedule_self: 645 * @new_ctx: the new context 646 * 647 * Move the currently running coroutine to new_ctx. If the coroutine is already 648 * running in new_ctx, do nothing. 649 */ 650 void coroutine_fn aio_co_reschedule_self(AioContext *new_ctx); 651 652 /** 653 * aio_co_wake: 654 * @co: the coroutine 655 * 656 * Restart a coroutine on the AioContext where it was running last, thus 657 * preventing coroutines from jumping from one context to another when they 658 * go to sleep. 659 * 660 * aio_co_wake may be executed either in coroutine or non-coroutine 661 * context. The coroutine must not be entered by anyone else while 662 * aio_co_wake() is active. 663 */ 664 void aio_co_wake(Coroutine *co); 665 666 /** 667 * aio_co_enter: 668 * @ctx: the context to run the coroutine 669 * @co: the coroutine to run 670 * 671 * Enter a coroutine in the specified AioContext. 672 */ 673 void aio_co_enter(AioContext *ctx, Coroutine *co); 674 675 /** 676 * Return the AioContext whose event loop runs in the current thread. 677 * 678 * If called from an IOThread this will be the IOThread's AioContext. If 679 * called from the main thread or with the "big QEMU lock" taken it 680 * will be the main loop AioContext. 681 */ 682 AioContext *qemu_get_current_aio_context(void); 683 684 void qemu_set_current_aio_context(AioContext *ctx); 685 686 /** 687 * aio_context_setup: 688 * @ctx: the aio context 689 * 690 * Initialize the aio context. 691 */ 692 void aio_context_setup(AioContext *ctx); 693 694 /** 695 * aio_context_destroy: 696 * @ctx: the aio context 697 * 698 * Destroy the aio context. 699 */ 700 void aio_context_destroy(AioContext *ctx); 701 702 /* Used internally, do not call outside AioContext code */ 703 void aio_context_use_g_source(AioContext *ctx); 704 705 /** 706 * aio_context_set_poll_params: 707 * @ctx: the aio context 708 * @max_ns: how long to busy poll for, in nanoseconds 709 * @grow: polling time growth factor 710 * @shrink: polling time shrink factor 711 * 712 * Poll mode can be disabled by setting poll_max_ns to 0. 713 */ 714 void aio_context_set_poll_params(AioContext *ctx, int64_t max_ns, 715 int64_t grow, int64_t shrink, 716 Error **errp); 717 718 /** 719 * aio_context_set_aio_params: 720 * @ctx: the aio context 721 * @max_batch: maximum number of requests in a batch, 0 means that the 722 * engine will use its default 723 */ 724 void aio_context_set_aio_params(AioContext *ctx, int64_t max_batch, 725 Error **errp); 726 727 /** 728 * aio_context_set_thread_pool_params: 729 * @ctx: the aio context 730 * @min: min number of threads to have readily available in the thread pool 731 * @min: max number of threads the thread pool can contain 732 */ 733 void aio_context_set_thread_pool_params(AioContext *ctx, int64_t min, 734 int64_t max, Error **errp); 735 #endif 736