1 /*- 2 * BSD LICENSE 3 * 4 * Copyright (c) Intel Corporation. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 11 * * Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * * Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in 15 * the documentation and/or other materials provided with the 16 * distribution. 17 * * Neither the name of Intel Corporation nor the names of its 18 * contributors may be used to endorse or promote products derived 19 * from this software without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 22 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 24 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 25 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 26 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 27 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 28 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 29 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 30 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 31 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 32 */ 33 34 /** \file 35 * Thread 36 */ 37 38 #ifndef SPDK_THREAD_H_ 39 #define SPDK_THREAD_H_ 40 41 #include "spdk/stdinc.h" 42 43 #include "spdk/cpuset.h" 44 #include "spdk/queue.h" 45 46 #ifdef __cplusplus 47 extern "C" { 48 #endif 49 50 struct spdk_thread; 51 struct spdk_io_channel_iter; 52 struct spdk_poller; 53 54 /** 55 * A function that is called each time a new thread is created. 56 * The implementor of this function should frequently call 57 * spdk_thread_poll() on the thread provided. 58 * 59 * \param thread The new spdk_thread. 60 */ 61 typedef int (*spdk_new_thread_fn)(struct spdk_thread *thread); 62 63 /** 64 * A function that will be called on the target thread. 65 * 66 * \param ctx Context passed as arg to spdk_thread_pass_msg(). 67 */ 68 typedef void (*spdk_msg_fn)(void *ctx); 69 70 /** 71 * Function to be called to pass a message to a thread. 72 * 73 * \param fn Callback function for a thread. 74 * \param ctx Context passed to fn. 75 * \param thread_ctx Context for the thread. 76 */ 77 typedef void (*spdk_thread_pass_msg)(spdk_msg_fn fn, void *ctx, 78 void *thread_ctx); 79 80 /** 81 * Callback function for a poller. 82 * 83 * \param ctx Context passed as arg to spdk_poller_register(). 84 * \return 0 to indicate that polling took place but no events were found; 85 * positive to indicate that polling took place and some events were processed; 86 * negative if the poller does not provide spin-wait information. 87 */ 88 typedef int (*spdk_poller_fn)(void *ctx); 89 90 /** 91 * Function to be called to start a poller for the thread. 92 * 93 * \param thread_ctx Context for the thread. 94 * \param fn Callback function for a poller. 95 * \param arg Argument passed to callback. 96 * \param period Polling period in microseconds. 97 * 98 * \return a pointer to the poller on success, or NULL on failure. 99 */ 100 typedef struct spdk_poller *(*spdk_start_poller)(void *thread_ctx, 101 spdk_poller_fn fn, 102 void *arg, 103 uint64_t period_microseconds); 104 105 /** 106 * Function to be called to stop a poller. 107 * 108 * \param poller Poller to stop. 109 * \param thread_ctx Context for the thread. 110 */ 111 typedef void (*spdk_stop_poller)(struct spdk_poller *poller, void *thread_ctx); 112 113 /** 114 * I/O channel creation callback. 115 * 116 * \param io_device I/O device associated with this channel. 117 * \param ctx_buf Context for the I/O device. 118 */ 119 typedef int (*spdk_io_channel_create_cb)(void *io_device, void *ctx_buf); 120 121 /** 122 * I/O channel destruction callback. 123 * 124 * \param io_device I/O device associated with this channel. 125 * \param ctx_buf Context for the I/O device. 126 */ 127 typedef void (*spdk_io_channel_destroy_cb)(void *io_device, void *ctx_buf); 128 129 /** 130 * I/O device unregister callback. 131 * 132 * \param io_device Unregistered I/O device. 133 */ 134 typedef void (*spdk_io_device_unregister_cb)(void *io_device); 135 136 /** 137 * Called on the appropriate thread for each channel associated with io_device. 138 * 139 * \param i I/O channel iterator. 140 */ 141 typedef void (*spdk_channel_msg)(struct spdk_io_channel_iter *i); 142 143 /** 144 * spdk_for_each_channel() callback. 145 * 146 * \param i I/O channel iterator. 147 * \param status 0 if it completed successfully, or negative errno if it failed. 148 */ 149 typedef void (*spdk_channel_for_each_cpl)(struct spdk_io_channel_iter *i, int status); 150 151 /** 152 * \brief Represents a per-thread channel for accessing an I/O device. 153 * 154 * An I/O device may be a physical entity (i.e. NVMe controller) or a software 155 * entity (i.e. a blobstore). 156 * 157 * This structure is not part of the API - all accesses should be done through 158 * spdk_io_channel function calls. 159 */ 160 struct spdk_io_channel { 161 struct spdk_thread *thread; 162 struct io_device *dev; 163 uint32_t ref; 164 uint32_t destroy_ref; 165 TAILQ_ENTRY(spdk_io_channel) tailq; 166 spdk_io_channel_destroy_cb destroy_cb; 167 168 /* 169 * Modules will allocate extra memory off the end of this structure 170 * to store references to hardware-specific references (i.e. NVMe queue 171 * pairs, or references to child device spdk_io_channels (i.e. 172 * virtual bdevs). 173 */ 174 }; 175 176 /** 177 * Initialize the threading library. Must be called once prior to allocating any threads. 178 * 179 * \param new_thread_fn Called each time a new SPDK thread is created. The implementor 180 * is expected to frequently call spdk_thread_poll() on the provided thread. 181 * \param ctx_sz For each thread allocated, an additional region of memory of 182 * size ctx_size will also be allocated, for use by the thread scheduler. A pointer 183 * to this region may be obtained by calling spdk_thread_get_ctx(). 184 * 185 * \return 0 on success. Negated errno on failure. 186 */ 187 int spdk_thread_lib_init(spdk_new_thread_fn new_thread_fn, size_t ctx_sz); 188 189 /** 190 * Release all resources associated with this library. 191 */ 192 void spdk_thread_lib_fini(void); 193 194 /** 195 * Creates a new SPDK thread object. 196 * 197 * \param name Human-readable name for the thread; can be retrieved with spdk_thread_get_name(). 198 * The string is copied, so the pointed-to data only needs to be valid during the 199 * spdk_thread_create() call. May be NULL to specify no name. 200 * \param cpumask Optional mask of CPU cores on which to schedule this thread. This is only 201 * a suggestion to the scheduler. The value is copied, so cpumask may be released when 202 * this function returns. May be NULL if no mask is required. 203 * 204 * \return a pointer to the allocated thread on success or NULL on failure.. 205 */ 206 struct spdk_thread *spdk_thread_create(const char *name, struct spdk_cpuset *cpumask); 207 208 /** 209 * Force the current system thread to act as if executing the given SPDK thread. 210 * 211 * \param thread The thread to set. 212 */ 213 void spdk_set_thread(struct spdk_thread *thread); 214 215 /** 216 * Mark the thread as exited, failing all future spdk_thread_poll() calls. May 217 * only be called within an spdk poller or message. 218 * 219 * 220 * \param thread The thread to destroy. 221 * 222 * All I/O channel references associated with the thread must be released using 223 * spdk_put_io_channel() prior to calling this function. 224 */ 225 void spdk_thread_exit(struct spdk_thread *thread); 226 227 /** 228 * Destroy a thread, releasing all of its resources. May only be called 229 * on a thread previously marked as exited. 230 * 231 * \param thread The thread to destroy. 232 * 233 */ 234 void spdk_thread_destroy(struct spdk_thread *thread); 235 236 /** 237 * Return a pointer to this thread's context. 238 * 239 * \param thread The thread on which to get the context. 240 * 241 * \return a pointer to the per-thread context, or NULL if there is 242 * no per-thread context. 243 */ 244 void *spdk_thread_get_ctx(struct spdk_thread *thread); 245 246 /** 247 * Get the thread's cpumask. 248 * 249 * \param thread The thread to get the cpumask for. 250 * 251 * \return cpuset pointer 252 */ 253 struct spdk_cpuset *spdk_thread_get_cpumask(struct spdk_thread *thread); 254 255 /** 256 * Return the thread object associated with the context handle previously 257 * obtained by calling spdk_thread_get_ctx(). 258 * 259 * \param ctx A context previously obtained by calling spdk_thread_get_ctx() 260 * 261 * \return The associated thread. 262 */ 263 struct spdk_thread *spdk_thread_get_from_ctx(void *ctx); 264 265 /** 266 * Perform one iteration worth of processing on the thread. This includes 267 * both expired and continuous pollers as well as messages. 268 * 269 * \param thread The thread to process 270 * \param max_msgs The maximum number of messages that will be processed. 271 * Use 0 to process the default number of messages (8). 272 * \param now The current time, in ticks. Optional. If 0 is passed, this 273 * function may call spdk_get_ticks() to get the current time. 274 * 275 * \return 1 if work was done. 0 if no work was done. -1 if thread has exited. 276 */ 277 int spdk_thread_poll(struct spdk_thread *thread, uint32_t max_msgs, uint64_t now); 278 279 /** 280 * Return the number of ticks until the next timed poller 281 * would expire. Timed pollers are pollers for which 282 * period_microseconds is greater than 0. 283 * 284 * \param thread The thread to check poller expiration times on 285 * 286 * \return Number of ticks. If no timed pollers, return 0. 287 */ 288 uint64_t spdk_thread_next_poller_expiration(struct spdk_thread *thread); 289 290 /** 291 * Returns whether there are any active pollers (pollers for which 292 * period_microseconds equals 0) registered to be run on the thread. 293 * 294 * \param thread The thread to check. 295 * 296 * \return 1 if there is at least one active poller, 0 otherwise. 297 */ 298 int spdk_thread_has_active_pollers(struct spdk_thread *thread); 299 300 /** 301 * Returns whether there are any pollers registered to be run 302 * on the thread. 303 * 304 * \param thread The thread to check. 305 * 306 * \return true if there is any active poller, false otherwise. 307 */ 308 bool spdk_thread_has_pollers(struct spdk_thread *thread); 309 310 /** 311 * Returns whether there are scheduled operations to be run on the thread. 312 * 313 * \param thread The thread to check. 314 * 315 * \return true if there are no scheduled operations, false otherwise. 316 */ 317 bool spdk_thread_is_idle(struct spdk_thread *thread); 318 319 /** 320 * Get count of allocated threads. 321 */ 322 uint32_t spdk_thread_get_count(void); 323 324 /** 325 * Get a handle to the current thread. 326 * 327 * This handle may be passed to other threads and used as the target of 328 * spdk_thread_send_msg(). 329 * 330 * \sa spdk_io_channel_get_thread() 331 * 332 * \return a pointer to the current thread on success or NULL on failure. 333 */ 334 struct spdk_thread *spdk_get_thread(void); 335 336 /** 337 * Get a thread's name. 338 * 339 * \param thread Thread to query. 340 * 341 * \return the name of the thread. 342 */ 343 const char *spdk_thread_get_name(const struct spdk_thread *thread); 344 345 struct spdk_thread_stats { 346 uint64_t busy_tsc; 347 uint64_t idle_tsc; 348 }; 349 350 /** 351 * Get statistics about the current thread. 352 * 353 * Copy cumulative thread stats values to the provided thread stats structure. 354 * 355 * \param stats User's thread_stats structure. 356 */ 357 int spdk_thread_get_stats(struct spdk_thread_stats *stats); 358 359 /** 360 * Send a message to the given thread. 361 * 362 * The message may be sent asynchronously - i.e. spdk_thread_send_msg may return 363 * prior to `fn` being called. 364 * 365 * \param thread The target thread. 366 * \param fn This function will be called on the given thread. 367 * \param ctx This context will be passed to fn when called. 368 */ 369 void spdk_thread_send_msg(const struct spdk_thread *thread, spdk_msg_fn fn, void *ctx); 370 371 /** 372 * Send a message to each thread, serially. 373 * 374 * The message is sent asynchronously - i.e. spdk_for_each_thread will return 375 * prior to `fn` being called on each thread. 376 * 377 * \param fn This is the function that will be called on each thread. 378 * \param ctx This context will be passed to fn when called. 379 * \param cpl This will be called on the originating thread after `fn` has been 380 * called on each thread. 381 */ 382 void spdk_for_each_thread(spdk_msg_fn fn, void *ctx, spdk_msg_fn cpl); 383 384 /** 385 * Register a poller on the current thread. 386 * 387 * The poller can be unregistered by calling spdk_poller_unregister(). 388 * 389 * \param fn This function will be called every `period_microseconds`. 390 * \param arg Argument passed to fn. 391 * \param period_microseconds How often to call `fn`. If 0, call `fn` as often 392 * as possible. 393 * 394 * \return a pointer to the poller registered on the current thread on success 395 * or NULL on failure. 396 */ 397 struct spdk_poller *spdk_poller_register(spdk_poller_fn fn, 398 void *arg, 399 uint64_t period_microseconds); 400 401 /** 402 * Unregister a poller on the current thread. 403 * 404 * \param ppoller The poller to unregister. 405 */ 406 void spdk_poller_unregister(struct spdk_poller **ppoller); 407 408 /** 409 * Register the opaque io_device context as an I/O device. 410 * 411 * After an I/O device is registered, it can return I/O channels using the 412 * spdk_get_io_channel() function. 413 * 414 * \param io_device The pointer to io_device context. 415 * \param create_cb Callback function invoked to allocate any resources required 416 * for a new I/O channel. 417 * \param destroy_cb Callback function invoked to release the resources for an 418 * I/O channel. 419 * \param ctx_size The size of the context buffer allocated to store references 420 * to allocated I/O channel resources. 421 * \param name A string name for the device used only for debugging. Optional - 422 * may be NULL. 423 */ 424 void spdk_io_device_register(void *io_device, spdk_io_channel_create_cb create_cb, 425 spdk_io_channel_destroy_cb destroy_cb, uint32_t ctx_size, 426 const char *name); 427 428 /** 429 * Unregister the opaque io_device context as an I/O device. 430 * 431 * The actual unregistration might be deferred until all active I/O channels are 432 * destroyed. 433 * 434 * \param io_device The pointer to io_device context. 435 * \param unregister_cb An optional callback function invoked to release any 436 * references to this I/O device. 437 */ 438 void spdk_io_device_unregister(void *io_device, spdk_io_device_unregister_cb unregister_cb); 439 440 /** 441 * Get an I/O channel for the specified io_device to be used by the calling thread. 442 * 443 * The io_device context pointer specified must have previously been registered 444 * using spdk_io_device_register(). If an existing I/O channel does not exist 445 * yet for the given io_device on the calling thread, it will allocate an I/O 446 * channel and invoke the create_cb function pointer specified in spdk_io_device_register(). 447 * If an I/O channel already exists for the given io_device on the calling thread, 448 * its reference is returned rather than creating a new I/O channel. 449 * 450 * \param io_device The pointer to io_device context. 451 * 452 * \return a pointer to the I/O channel for this device on success or NULL on failure. 453 */ 454 struct spdk_io_channel *spdk_get_io_channel(void *io_device); 455 456 /** 457 * Release a reference to an I/O channel. This happens asynchronously. 458 * 459 * Actual release will happen on the same thread that called spdk_get_io_channel() 460 * for the specified I/O channel. If this releases the last reference to the 461 * I/O channel, The destroy_cb function specified in spdk_io_device_register() 462 * will be invoked to release any associated resources. 463 * 464 * \param ch I/O channel to release a reference. 465 */ 466 void spdk_put_io_channel(struct spdk_io_channel *ch); 467 468 /** 469 * Get the context buffer associated with an I/O channel. 470 * 471 * \param ch I/O channel. 472 * 473 * \return a pointer to the context buffer. 474 */ 475 static inline void * 476 spdk_io_channel_get_ctx(struct spdk_io_channel *ch) 477 { 478 return (uint8_t *)ch + sizeof(*ch); 479 } 480 481 /** 482 * Get I/O channel from the context buffer. This is the inverse of 483 * spdk_io_channel_get_ctx(). 484 * 485 * \param ctx The pointer to the context buffer. 486 * 487 * \return a pointer to the I/O channel associated with the context buffer. 488 */ 489 struct spdk_io_channel *spdk_io_channel_from_ctx(void *ctx); 490 491 /** 492 * Get the thread associated with an I/O channel. 493 * 494 * \param ch I/O channel. 495 * 496 * \return a pointer to the thread associated with the I/O channel 497 */ 498 struct spdk_thread *spdk_io_channel_get_thread(struct spdk_io_channel *ch); 499 500 /** 501 * Call 'fn' on each channel associated with io_device. 502 * 503 * This happens asynchronously, so fn may be called after spdk_for_each_channel 504 * returns. 'fn' will be called for each channel serially, such that two calls 505 * to 'fn' will not overlap in time. After 'fn' has been called, call 506 * spdk_for_each_channel_continue() to continue iterating. 507 * 508 * \param io_device 'fn' will be called on each channel associated with this io_device. 509 * \param fn Called on the appropriate thread for each channel associated with io_device. 510 * \param ctx Context buffer registered to spdk_io_channel_iter that can be obatined 511 * form the function spdk_io_channel_iter_get_ctx(). 512 * \param cpl Called on the thread that spdk_for_each_channel was initially called 513 * from when 'fn' has been called on each channel. 514 */ 515 void spdk_for_each_channel(void *io_device, spdk_channel_msg fn, void *ctx, 516 spdk_channel_for_each_cpl cpl); 517 518 /** 519 * Get io_device from the I/O channel iterator. 520 * 521 * \param i I/O channel iterator. 522 * 523 * \return a pointer to the io_device. 524 */ 525 void *spdk_io_channel_iter_get_io_device(struct spdk_io_channel_iter *i); 526 527 /** 528 * Get I/O channel from the I/O channel iterator. 529 * 530 * \param i I/O channel iterator. 531 * 532 * \return a pointer to the I/O channel. 533 */ 534 struct spdk_io_channel *spdk_io_channel_iter_get_channel(struct spdk_io_channel_iter *i); 535 536 /** 537 * Get context buffer from the I/O channel iterator. 538 * 539 * \param i I/O channel iterator. 540 * 541 * \return a pointer to the context buffer. 542 */ 543 void *spdk_io_channel_iter_get_ctx(struct spdk_io_channel_iter *i); 544 545 /** 546 * Helper function to iterate all channels for spdk_for_each_channel(). 547 * 548 * \param i I/O channel iterator. 549 * \param status Status for the I/O channel iterator. 550 */ 551 void spdk_for_each_channel_continue(struct spdk_io_channel_iter *i, int status); 552 553 #ifdef __cplusplus 554 } 555 #endif 556 557 #endif /* SPDK_THREAD_H_ */ 558