| 1 | /* $NetBSD: kern_turnstile.c,v 1.32 2012/06/15 13:51:40 yamt Exp $ */ |
| 2 | |
| 3 | /*- |
| 4 | * Copyright (c) 2002, 2006, 2007, 2009 The NetBSD Foundation, Inc. |
| 5 | * All rights reserved. |
| 6 | * |
| 7 | * This code is derived from software contributed to The NetBSD Foundation |
| 8 | * by Jason R. Thorpe and Andrew Doran. |
| 9 | * |
| 10 | * Redistribution and use in source and binary forms, with or without |
| 11 | * modification, are permitted provided that the following conditions |
| 12 | * are met: |
| 13 | * 1. Redistributions of source code must retain the above copyright |
| 14 | * notice, this list of conditions and the following disclaimer. |
| 15 | * 2. Redistributions in binary form must reproduce the above copyright |
| 16 | * notice, this list of conditions and the following disclaimer in the |
| 17 | * documentation and/or other materials provided with the distribution. |
| 18 | * |
| 19 | * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS |
| 20 | * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED |
| 21 | * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
| 22 | * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS |
| 23 | * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
| 24 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
| 25 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
| 26 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
| 27 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| 28 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
| 29 | * POSSIBILITY OF SUCH DAMAGE. |
| 30 | */ |
| 31 | |
| 32 | /* |
| 33 | * Turnstiles are described in detail in: |
| 34 | * |
| 35 | * Solaris Internals: Core Kernel Architecture, Jim Mauro and |
| 36 | * Richard McDougall. |
| 37 | * |
| 38 | * Turnstiles are kept in a hash table. There are likely to be many more |
| 39 | * synchronisation objects than there are threads. Since a thread can block |
| 40 | * on only one lock at a time, we only need one turnstile per thread, and |
| 41 | * so they are allocated at thread creation time. |
| 42 | * |
| 43 | * When a thread decides it needs to block on a lock, it looks up the |
| 44 | * active turnstile for that lock. If no active turnstile exists, then |
| 45 | * the process lends its turnstile to the lock. If there is already an |
| 46 | * active turnstile for the lock, the thread places its turnstile on a |
| 47 | * list of free turnstiles, and references the active one instead. |
| 48 | * |
| 49 | * The act of looking up the turnstile acquires an interlock on the sleep |
| 50 | * queue. If a thread decides it doesn't need to block after all, then this |
| 51 | * interlock must be released by explicitly aborting the turnstile |
| 52 | * operation. |
| 53 | * |
| 54 | * When a thread is awakened, it needs to get its turnstile back. If there |
| 55 | * are still other threads waiting in the active turnstile, the thread |
| 56 | * grabs a free turnstile off the free list. Otherwise, it can take back |
| 57 | * the active turnstile from the lock (thus deactivating the turnstile). |
| 58 | * |
| 59 | * Turnstiles are the place to do priority inheritence. |
| 60 | */ |
| 61 | |
| 62 | #include <sys/cdefs.h> |
| 63 | __KERNEL_RCSID(0, "$NetBSD: kern_turnstile.c,v 1.32 2012/06/15 13:51:40 yamt Exp $" ); |
| 64 | |
| 65 | #include <sys/param.h> |
| 66 | #include <sys/lockdebug.h> |
| 67 | #include <sys/pool.h> |
| 68 | #include <sys/proc.h> |
| 69 | #include <sys/sleepq.h> |
| 70 | #include <sys/systm.h> |
| 71 | |
| 72 | #define TS_HASH_SIZE 64 |
| 73 | #define TS_HASH_MASK (TS_HASH_SIZE - 1) |
| 74 | #define TS_HASH(obj) (((uintptr_t)(obj) >> 3) & TS_HASH_MASK) |
| 75 | |
| 76 | static tschain_t turnstile_tab[TS_HASH_SIZE] __cacheline_aligned; |
| 77 | pool_cache_t turnstile_cache __read_mostly; |
| 78 | |
| 79 | static int turnstile_ctor(void *, void *, int); |
| 80 | |
| 81 | extern turnstile_t turnstile0; |
| 82 | |
| 83 | /* |
| 84 | * turnstile_init: |
| 85 | * |
| 86 | * Initialize the turnstile mechanism. |
| 87 | */ |
| 88 | void |
| 89 | turnstile_init(void) |
| 90 | { |
| 91 | tschain_t *tc; |
| 92 | int i; |
| 93 | |
| 94 | for (i = 0; i < TS_HASH_SIZE; i++) { |
| 95 | tc = &turnstile_tab[i]; |
| 96 | LIST_INIT(&tc->tc_chain); |
| 97 | tc->tc_mutex = mutex_obj_alloc(MUTEX_DEFAULT, IPL_SCHED); |
| 98 | } |
| 99 | |
| 100 | turnstile_cache = pool_cache_init(sizeof(turnstile_t), 0, 0, 0, |
| 101 | "tstilepl" , NULL, IPL_NONE, turnstile_ctor, NULL, NULL); |
| 102 | KASSERT(turnstile_cache != NULL); |
| 103 | |
| 104 | (void)turnstile_ctor(NULL, &turnstile0, 0); |
| 105 | } |
| 106 | |
| 107 | /* |
| 108 | * turnstile_ctor: |
| 109 | * |
| 110 | * Constructor for turnstiles. |
| 111 | */ |
| 112 | static int |
| 113 | turnstile_ctor(void *arg, void *obj, int flags) |
| 114 | { |
| 115 | turnstile_t *ts = obj; |
| 116 | |
| 117 | memset(ts, 0, sizeof(*ts)); |
| 118 | sleepq_init(&ts->ts_sleepq[TS_READER_Q]); |
| 119 | sleepq_init(&ts->ts_sleepq[TS_WRITER_Q]); |
| 120 | return (0); |
| 121 | } |
| 122 | |
| 123 | /* |
| 124 | * turnstile_remove: |
| 125 | * |
| 126 | * Remove an LWP from a turnstile sleep queue and wake it. |
| 127 | */ |
| 128 | static inline void |
| 129 | turnstile_remove(turnstile_t *ts, lwp_t *l, int q) |
| 130 | { |
| 131 | turnstile_t *nts; |
| 132 | |
| 133 | KASSERT(l->l_ts == ts); |
| 134 | |
| 135 | /* |
| 136 | * This process is no longer using the active turnstile. |
| 137 | * Find an inactive one on the free list to give to it. |
| 138 | */ |
| 139 | if ((nts = ts->ts_free) != NULL) { |
| 140 | KASSERT(TS_ALL_WAITERS(ts) > 1); |
| 141 | l->l_ts = nts; |
| 142 | ts->ts_free = nts->ts_free; |
| 143 | nts->ts_free = NULL; |
| 144 | } else { |
| 145 | /* |
| 146 | * If the free list is empty, this is the last |
| 147 | * waiter. |
| 148 | */ |
| 149 | KASSERT(TS_ALL_WAITERS(ts) == 1); |
| 150 | LIST_REMOVE(ts, ts_chain); |
| 151 | } |
| 152 | |
| 153 | ts->ts_waiters[q]--; |
| 154 | sleepq_remove(&ts->ts_sleepq[q], l); |
| 155 | } |
| 156 | |
| 157 | /* |
| 158 | * turnstile_lookup: |
| 159 | * |
| 160 | * Look up the turnstile for the specified lock. This acquires and |
| 161 | * holds the turnstile chain lock (sleep queue interlock). |
| 162 | */ |
| 163 | turnstile_t * |
| 164 | turnstile_lookup(wchan_t obj) |
| 165 | { |
| 166 | turnstile_t *ts; |
| 167 | tschain_t *tc; |
| 168 | |
| 169 | tc = &turnstile_tab[TS_HASH(obj)]; |
| 170 | mutex_spin_enter(tc->tc_mutex); |
| 171 | |
| 172 | LIST_FOREACH(ts, &tc->tc_chain, ts_chain) |
| 173 | if (ts->ts_obj == obj) |
| 174 | return (ts); |
| 175 | |
| 176 | /* |
| 177 | * No turnstile yet for this lock. No problem, turnstile_block() |
| 178 | * handles this by fetching the turnstile from the blocking thread. |
| 179 | */ |
| 180 | return (NULL); |
| 181 | } |
| 182 | |
| 183 | /* |
| 184 | * turnstile_exit: |
| 185 | * |
| 186 | * Abort a turnstile operation. |
| 187 | */ |
| 188 | void |
| 189 | turnstile_exit(wchan_t obj) |
| 190 | { |
| 191 | tschain_t *tc; |
| 192 | |
| 193 | tc = &turnstile_tab[TS_HASH(obj)]; |
| 194 | mutex_spin_exit(tc->tc_mutex); |
| 195 | } |
| 196 | |
| 197 | /* |
| 198 | * turnstile_lendpri: |
| 199 | * |
| 200 | * Lend our priority to lwps on the blocking chain. |
| 201 | * |
| 202 | * If the current owner of the lock (l->l_wchan, set by sleepq_enqueue) |
| 203 | * has a priority lower than ours (lwp_eprio(l)), lend our priority to |
| 204 | * him to avoid priority inversions. |
| 205 | */ |
| 206 | |
| 207 | static void |
| 208 | turnstile_lendpri(lwp_t *cur) |
| 209 | { |
| 210 | lwp_t * l = cur; |
| 211 | pri_t prio; |
| 212 | |
| 213 | /* |
| 214 | * NOTE: if you get a panic in this code block, it is likely that |
| 215 | * a lock has been destroyed or corrupted while still in use. Try |
| 216 | * compiling a kernel with LOCKDEBUG to pinpoint the problem. |
| 217 | */ |
| 218 | |
| 219 | LOCKDEBUG_BARRIER(l->l_mutex, 1); |
| 220 | KASSERT(l == curlwp); |
| 221 | prio = lwp_eprio(l); |
| 222 | for (;;) { |
| 223 | lwp_t *owner; |
| 224 | turnstile_t *ts; |
| 225 | bool dolock; |
| 226 | |
| 227 | if (l->l_wchan == NULL) |
| 228 | break; |
| 229 | |
| 230 | /* |
| 231 | * Ask syncobj the owner of the lock. |
| 232 | */ |
| 233 | owner = (*l->l_syncobj->sobj_owner)(l->l_wchan); |
| 234 | if (owner == NULL) |
| 235 | break; |
| 236 | |
| 237 | /* |
| 238 | * The owner may have changed as we have dropped the tc lock. |
| 239 | */ |
| 240 | if (cur == owner) { |
| 241 | /* |
| 242 | * We own the lock: stop here, sleepq_block() |
| 243 | * should wake up immediatly. |
| 244 | */ |
| 245 | break; |
| 246 | } |
| 247 | /* |
| 248 | * Acquire owner->l_mutex if we don't have it yet. |
| 249 | * Because we already have another LWP lock (l->l_mutex) held, |
| 250 | * we need to play a try lock dance to avoid deadlock. |
| 251 | */ |
| 252 | dolock = l->l_mutex != owner->l_mutex; |
| 253 | if (l == owner || (dolock && !lwp_trylock(owner))) { |
| 254 | /* |
| 255 | * The owner was changed behind us or trylock failed. |
| 256 | * Restart from curlwp. |
| 257 | * |
| 258 | * Note that there may be a livelock here: |
| 259 | * the owner may try grabing cur's lock (which is the |
| 260 | * tc lock) while we're trying to grab the owner's lock. |
| 261 | */ |
| 262 | lwp_unlock(l); |
| 263 | l = cur; |
| 264 | lwp_lock(l); |
| 265 | prio = lwp_eprio(l); |
| 266 | continue; |
| 267 | } |
| 268 | /* |
| 269 | * If the owner's priority is already higher than ours, |
| 270 | * there's nothing to do anymore. |
| 271 | */ |
| 272 | if (prio <= lwp_eprio(owner)) { |
| 273 | if (dolock) |
| 274 | lwp_unlock(owner); |
| 275 | break; |
| 276 | } |
| 277 | /* |
| 278 | * Lend our priority to the 'owner' LWP. |
| 279 | * |
| 280 | * Update lenders info for turnstile_unlendpri. |
| 281 | */ |
| 282 | ts = l->l_ts; |
| 283 | KASSERT(ts->ts_inheritor == owner || ts->ts_inheritor == NULL); |
| 284 | if (ts->ts_inheritor == NULL) { |
| 285 | ts->ts_inheritor = owner; |
| 286 | ts->ts_eprio = prio; |
| 287 | SLIST_INSERT_HEAD(&owner->l_pi_lenders, ts, ts_pichain); |
| 288 | lwp_lendpri(owner, prio); |
| 289 | } else if (prio > ts->ts_eprio) { |
| 290 | ts->ts_eprio = prio; |
| 291 | lwp_lendpri(owner, prio); |
| 292 | } |
| 293 | if (dolock) |
| 294 | lwp_unlock(l); |
| 295 | LOCKDEBUG_BARRIER(owner->l_mutex, 1); |
| 296 | l = owner; |
| 297 | } |
| 298 | LOCKDEBUG_BARRIER(l->l_mutex, 1); |
| 299 | if (cur->l_mutex != l->l_mutex) { |
| 300 | lwp_unlock(l); |
| 301 | lwp_lock(cur); |
| 302 | } |
| 303 | LOCKDEBUG_BARRIER(cur->l_mutex, 1); |
| 304 | } |
| 305 | |
| 306 | /* |
| 307 | * turnstile_unlendpri: undo turnstile_lendpri |
| 308 | */ |
| 309 | |
| 310 | static void |
| 311 | turnstile_unlendpri(turnstile_t *ts) |
| 312 | { |
| 313 | lwp_t * const l = curlwp; |
| 314 | turnstile_t *iter; |
| 315 | turnstile_t *next; |
| 316 | turnstile_t *prev = NULL; |
| 317 | pri_t prio; |
| 318 | bool dolock; |
| 319 | |
| 320 | KASSERT(ts->ts_inheritor != NULL); |
| 321 | ts->ts_inheritor = NULL; |
| 322 | dolock = l->l_mutex == l->l_cpu->ci_schedstate.spc_lwplock; |
| 323 | if (dolock) { |
| 324 | lwp_lock(l); |
| 325 | } |
| 326 | |
| 327 | /* |
| 328 | * the following loop does two things. |
| 329 | * |
| 330 | * - remove ts from the list. |
| 331 | * |
| 332 | * - from the rest of the list, find the highest priority. |
| 333 | */ |
| 334 | |
| 335 | prio = -1; |
| 336 | KASSERT(!SLIST_EMPTY(&l->l_pi_lenders)); |
| 337 | for (iter = SLIST_FIRST(&l->l_pi_lenders); |
| 338 | iter != NULL; iter = next) { |
| 339 | KASSERT(lwp_eprio(l) >= ts->ts_eprio); |
| 340 | next = SLIST_NEXT(iter, ts_pichain); |
| 341 | if (iter == ts) { |
| 342 | if (prev == NULL) { |
| 343 | SLIST_REMOVE_HEAD(&l->l_pi_lenders, |
| 344 | ts_pichain); |
| 345 | } else { |
| 346 | SLIST_REMOVE_AFTER(prev, ts_pichain); |
| 347 | } |
| 348 | } else if (prio < iter->ts_eprio) { |
| 349 | prio = iter->ts_eprio; |
| 350 | } |
| 351 | prev = iter; |
| 352 | } |
| 353 | |
| 354 | lwp_lendpri(l, prio); |
| 355 | |
| 356 | if (dolock) { |
| 357 | lwp_unlock(l); |
| 358 | } |
| 359 | } |
| 360 | |
| 361 | /* |
| 362 | * turnstile_block: |
| 363 | * |
| 364 | * Enter an object into the turnstile chain and prepare the current |
| 365 | * LWP for sleep. |
| 366 | */ |
| 367 | void |
| 368 | turnstile_block(turnstile_t *ts, int q, wchan_t obj, syncobj_t *sobj) |
| 369 | { |
| 370 | lwp_t * const l = curlwp; /* cached curlwp */ |
| 371 | turnstile_t *ots; |
| 372 | tschain_t *tc; |
| 373 | sleepq_t *sq; |
| 374 | pri_t obase; |
| 375 | |
| 376 | tc = &turnstile_tab[TS_HASH(obj)]; |
| 377 | |
| 378 | KASSERT(q == TS_READER_Q || q == TS_WRITER_Q); |
| 379 | KASSERT(mutex_owned(tc->tc_mutex)); |
| 380 | KASSERT(l != NULL && l->l_ts != NULL); |
| 381 | |
| 382 | if (ts == NULL) { |
| 383 | /* |
| 384 | * We are the first thread to wait for this object; |
| 385 | * lend our turnstile to it. |
| 386 | */ |
| 387 | ts = l->l_ts; |
| 388 | KASSERT(TS_ALL_WAITERS(ts) == 0); |
| 389 | KASSERT(TAILQ_EMPTY(&ts->ts_sleepq[TS_READER_Q]) && |
| 390 | TAILQ_EMPTY(&ts->ts_sleepq[TS_WRITER_Q])); |
| 391 | ts->ts_obj = obj; |
| 392 | ts->ts_inheritor = NULL; |
| 393 | LIST_INSERT_HEAD(&tc->tc_chain, ts, ts_chain); |
| 394 | } else { |
| 395 | /* |
| 396 | * Object already has a turnstile. Put our turnstile |
| 397 | * onto the free list, and reference the existing |
| 398 | * turnstile instead. |
| 399 | */ |
| 400 | ots = l->l_ts; |
| 401 | KASSERT(ots->ts_free == NULL); |
| 402 | ots->ts_free = ts->ts_free; |
| 403 | ts->ts_free = ots; |
| 404 | l->l_ts = ts; |
| 405 | |
| 406 | KASSERT(ts->ts_obj == obj); |
| 407 | KASSERT(TS_ALL_WAITERS(ts) != 0); |
| 408 | KASSERT(!TAILQ_EMPTY(&ts->ts_sleepq[TS_READER_Q]) || |
| 409 | !TAILQ_EMPTY(&ts->ts_sleepq[TS_WRITER_Q])); |
| 410 | } |
| 411 | |
| 412 | sq = &ts->ts_sleepq[q]; |
| 413 | ts->ts_waiters[q]++; |
| 414 | sleepq_enter(sq, l, tc->tc_mutex); |
| 415 | LOCKDEBUG_BARRIER(tc->tc_mutex, 1); |
| 416 | l->l_kpriority = true; |
| 417 | obase = l->l_kpribase; |
| 418 | if (obase < PRI_KTHREAD) |
| 419 | l->l_kpribase = PRI_KTHREAD; |
| 420 | sleepq_enqueue(sq, obj, "tstile" , sobj); |
| 421 | |
| 422 | /* |
| 423 | * Disable preemption across this entire block, as we may drop |
| 424 | * scheduler locks (allowing preemption), and would prefer not |
| 425 | * to be interrupted while in a state of flux. |
| 426 | */ |
| 427 | KPREEMPT_DISABLE(l); |
| 428 | KASSERT(tc->tc_mutex == l->l_mutex); |
| 429 | turnstile_lendpri(l); |
| 430 | sleepq_block(0, false); |
| 431 | l->l_kpribase = obase; |
| 432 | KPREEMPT_ENABLE(l); |
| 433 | } |
| 434 | |
| 435 | /* |
| 436 | * turnstile_wakeup: |
| 437 | * |
| 438 | * Wake up the specified number of threads that are blocked |
| 439 | * in a turnstile. |
| 440 | */ |
| 441 | void |
| 442 | turnstile_wakeup(turnstile_t *ts, int q, int count, lwp_t *nl) |
| 443 | { |
| 444 | sleepq_t *sq; |
| 445 | tschain_t *tc; |
| 446 | lwp_t *l; |
| 447 | |
| 448 | tc = &turnstile_tab[TS_HASH(ts->ts_obj)]; |
| 449 | sq = &ts->ts_sleepq[q]; |
| 450 | |
| 451 | KASSERT(q == TS_READER_Q || q == TS_WRITER_Q); |
| 452 | KASSERT(count > 0 && count <= TS_WAITERS(ts, q)); |
| 453 | KASSERT(mutex_owned(tc->tc_mutex)); |
| 454 | KASSERT(ts->ts_inheritor == curlwp || ts->ts_inheritor == NULL); |
| 455 | |
| 456 | /* |
| 457 | * restore inherited priority if necessary. |
| 458 | */ |
| 459 | |
| 460 | if (ts->ts_inheritor != NULL) { |
| 461 | turnstile_unlendpri(ts); |
| 462 | } |
| 463 | |
| 464 | if (nl != NULL) { |
| 465 | #if defined(DEBUG) || defined(LOCKDEBUG) |
| 466 | TAILQ_FOREACH(l, sq, l_sleepchain) { |
| 467 | if (l == nl) |
| 468 | break; |
| 469 | } |
| 470 | if (l == NULL) |
| 471 | panic("turnstile_wakeup: nl not on sleepq" ); |
| 472 | #endif |
| 473 | turnstile_remove(ts, nl, q); |
| 474 | } else { |
| 475 | while (count-- > 0) { |
| 476 | l = TAILQ_FIRST(sq); |
| 477 | KASSERT(l != NULL); |
| 478 | turnstile_remove(ts, l, q); |
| 479 | } |
| 480 | } |
| 481 | mutex_spin_exit(tc->tc_mutex); |
| 482 | } |
| 483 | |
| 484 | /* |
| 485 | * turnstile_unsleep: |
| 486 | * |
| 487 | * Remove an LWP from the turnstile. This is called when the LWP has |
| 488 | * not been awoken normally but instead interrupted: for example, if it |
| 489 | * has received a signal. It's not a valid action for turnstiles, |
| 490 | * since LWPs blocking on a turnstile are not interruptable. |
| 491 | */ |
| 492 | void |
| 493 | turnstile_unsleep(lwp_t *l, bool cleanup) |
| 494 | { |
| 495 | |
| 496 | lwp_unlock(l); |
| 497 | panic("turnstile_unsleep" ); |
| 498 | } |
| 499 | |
| 500 | /* |
| 501 | * turnstile_changepri: |
| 502 | * |
| 503 | * Adjust the priority of an LWP residing on a turnstile. |
| 504 | */ |
| 505 | void |
| 506 | turnstile_changepri(lwp_t *l, pri_t pri) |
| 507 | { |
| 508 | |
| 509 | /* XXX priority inheritance */ |
| 510 | sleepq_changepri(l, pri); |
| 511 | } |
| 512 | |
| 513 | #if defined(LOCKDEBUG) |
| 514 | /* |
| 515 | * turnstile_print: |
| 516 | * |
| 517 | * Given the address of a lock object, print the contents of a |
| 518 | * turnstile. |
| 519 | */ |
| 520 | void |
| 521 | turnstile_print(volatile void *obj, void (*pr)(const char *, ...)) |
| 522 | { |
| 523 | turnstile_t *ts; |
| 524 | tschain_t *tc; |
| 525 | sleepq_t *rsq, *wsq; |
| 526 | lwp_t *l; |
| 527 | |
| 528 | tc = &turnstile_tab[TS_HASH(obj)]; |
| 529 | |
| 530 | LIST_FOREACH(ts, &tc->tc_chain, ts_chain) |
| 531 | if (ts->ts_obj == obj) |
| 532 | break; |
| 533 | |
| 534 | (*pr)("Turnstile chain at %p.\n" , tc); |
| 535 | if (ts == NULL) { |
| 536 | (*pr)("=> No active turnstile for this lock.\n" ); |
| 537 | return; |
| 538 | } |
| 539 | |
| 540 | rsq = &ts->ts_sleepq[TS_READER_Q]; |
| 541 | wsq = &ts->ts_sleepq[TS_WRITER_Q]; |
| 542 | |
| 543 | (*pr)("=> Turnstile at %p (wrq=%p, rdq=%p).\n" , ts, rsq, wsq); |
| 544 | |
| 545 | (*pr)("=> %d waiting readers:" , TS_WAITERS(ts, TS_READER_Q)); |
| 546 | TAILQ_FOREACH(l, rsq, l_sleepchain) { |
| 547 | (*pr)(" %p" , l); |
| 548 | } |
| 549 | (*pr)("\n" ); |
| 550 | |
| 551 | (*pr)("=> %d waiting writers:" , TS_WAITERS(ts, TS_WRITER_Q)); |
| 552 | TAILQ_FOREACH(l, wsq, l_sleepchain) { |
| 553 | (*pr)(" %p" , l); |
| 554 | } |
| 555 | (*pr)("\n" ); |
| 556 | } |
| 557 | #endif /* LOCKDEBUG */ |
| 558 | |