1 /*- 2 * Copyright (c) 1982, 1986, 1990, 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * (c) UNIX System Laboratories, Inc. 5 * All or some portions of this file are derived from material licensed 6 * to the University of California by American Telephone and Telegraph 7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 8 * the permission of UNIX System Laboratories, Inc. 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 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * @(#)kern_synch.c 8.9 (Berkeley) 5/19/95 35 * $FreeBSD: src/sys/kern/kern_synch.c,v 1.87.2.6 2002/10/13 07:29:53 kbyanc Exp $ 36 */ 37 38 #include "opt_ktrace.h" 39 40 #include <sys/param.h> 41 #include <sys/systm.h> 42 #include <sys/proc.h> 43 #include <sys/kernel.h> 44 #include <sys/signalvar.h> 45 #include <sys/resourcevar.h> 46 #include <sys/vmmeter.h> 47 #include <sys/sysctl.h> 48 #include <sys/lock.h> 49 #include <sys/uio.h> 50 #include <sys/priv.h> 51 #include <sys/kcollect.h> 52 #ifdef KTRACE 53 #include <sys/ktrace.h> 54 #endif 55 #include <sys/ktr.h> 56 #include <sys/serialize.h> 57 58 #include <sys/signal2.h> 59 #include <sys/thread2.h> 60 #include <sys/spinlock2.h> 61 #include <sys/mutex2.h> 62 63 #include <machine/cpu.h> 64 #include <machine/smp.h> 65 66 #include <vm/vm_extern.h> 67 68 struct tslpque { 69 TAILQ_HEAD(, thread) queue; 70 const volatile void *ident0; 71 const volatile void *ident1; 72 const volatile void *ident2; 73 const volatile void *ident3; 74 }; 75 76 static void sched_setup (void *dummy); 77 SYSINIT(sched_setup, SI_SUB_KICK_SCHEDULER, SI_ORDER_FIRST, sched_setup, NULL); 78 static void sched_dyninit (void *dummy); 79 SYSINIT(sched_dyninit, SI_BOOT1_DYNALLOC, SI_ORDER_FIRST, sched_dyninit, NULL); 80 81 int lbolt; 82 void *lbolt_syncer; 83 __read_mostly int tsleep_crypto_dump = 0; 84 __read_mostly int ncpus; 85 __read_mostly int ncpus_fit, ncpus_fit_mask; /* note: mask not cpumask_t */ 86 __read_mostly int safepri; 87 __read_mostly int tsleep_now_works; 88 89 MALLOC_DEFINE(M_TSLEEP, "tslpque", "tsleep queues"); 90 91 #define __DEALL(ident) __DEQUALIFY(void *, ident) 92 93 #if !defined(KTR_TSLEEP) 94 #define KTR_TSLEEP KTR_ALL 95 #endif 96 KTR_INFO_MASTER(tsleep); 97 KTR_INFO(KTR_TSLEEP, tsleep, tsleep_beg, 0, "tsleep enter %p", const volatile void *ident); 98 KTR_INFO(KTR_TSLEEP, tsleep, tsleep_end, 1, "tsleep exit"); 99 KTR_INFO(KTR_TSLEEP, tsleep, wakeup_beg, 2, "wakeup enter %p", const volatile void *ident); 100 KTR_INFO(KTR_TSLEEP, tsleep, wakeup_end, 3, "wakeup exit"); 101 KTR_INFO(KTR_TSLEEP, tsleep, ilockfail, 4, "interlock failed %p", const volatile void *ident); 102 103 #define logtsleep1(name) KTR_LOG(tsleep_ ## name) 104 #define logtsleep2(name, val) KTR_LOG(tsleep_ ## name, val) 105 106 __exclusive_cache_line 107 struct loadavg averunnable = 108 { {0, 0, 0}, FSCALE }; /* load average, of runnable procs */ 109 /* 110 * Constants for averages over 1, 5, and 15 minutes 111 * when sampling at 5 second intervals. 112 */ 113 __read_mostly 114 static fixpt_t cexp[3] = { 115 0.9200444146293232 * FSCALE, /* exp(-1/12) */ 116 0.9834714538216174 * FSCALE, /* exp(-1/60) */ 117 0.9944598480048967 * FSCALE, /* exp(-1/180) */ 118 }; 119 120 static void endtsleep (void *); 121 static void loadav (void *arg); 122 static void schedcpu (void *arg); 123 124 __read_mostly static int pctcpu_decay = 10; 125 SYSCTL_INT(_kern, OID_AUTO, pctcpu_decay, CTLFLAG_RW, 126 &pctcpu_decay, 0, ""); 127 128 /* 129 * kernel uses `FSCALE', userland (SHOULD) use kern.fscale 130 */ 131 __read_mostly int fscale __unused = FSCALE; /* exported to systat */ 132 SYSCTL_INT(_kern, OID_AUTO, fscale, CTLFLAG_RD, 0, FSCALE, ""); 133 134 /* 135 * Issue a wakeup() from userland (debugging) 136 */ 137 static int 138 sysctl_wakeup(SYSCTL_HANDLER_ARGS) 139 { 140 uint64_t ident = 1; 141 int error = 0; 142 143 if (req->newptr != NULL) { 144 if (priv_check(curthread, PRIV_ROOT)) 145 return (EPERM); 146 error = SYSCTL_IN(req, &ident, sizeof(ident)); 147 if (error) 148 return error; 149 kprintf("issue wakeup %016jx\n", ident); 150 wakeup((void *)(intptr_t)ident); 151 } 152 if (req->oldptr != NULL) { 153 error = SYSCTL_OUT(req, &ident, sizeof(ident)); 154 } 155 return error; 156 } 157 158 static int 159 sysctl_wakeup_umtx(SYSCTL_HANDLER_ARGS) 160 { 161 uint64_t ident = 1; 162 int error = 0; 163 164 if (req->newptr != NULL) { 165 if (priv_check(curthread, PRIV_ROOT)) 166 return (EPERM); 167 error = SYSCTL_IN(req, &ident, sizeof(ident)); 168 if (error) 169 return error; 170 kprintf("issue wakeup %016jx, PDOMAIN_UMTX\n", ident); 171 wakeup_domain((void *)(intptr_t)ident, PDOMAIN_UMTX); 172 } 173 if (req->oldptr != NULL) { 174 error = SYSCTL_OUT(req, &ident, sizeof(ident)); 175 } 176 return error; 177 } 178 179 SYSCTL_PROC(_debug, OID_AUTO, wakeup, CTLTYPE_UQUAD|CTLFLAG_RW, 0, 0, 180 sysctl_wakeup, "Q", "issue wakeup(addr)"); 181 SYSCTL_PROC(_debug, OID_AUTO, wakeup_umtx, CTLTYPE_UQUAD|CTLFLAG_RW, 0, 0, 182 sysctl_wakeup_umtx, "Q", "issue wakeup(addr, PDOMAIN_UMTX)"); 183 184 /* 185 * Recompute process priorities, once a second. 186 * 187 * Since the userland schedulers are typically event oriented, if the 188 * estcpu calculation at wakeup() time is not sufficient to make a 189 * process runnable relative to other processes in the system we have 190 * a 1-second recalc to help out. 191 * 192 * This code also allows us to store sysclock_t data in the process structure 193 * without fear of an overrun, since sysclock_t are guarenteed to hold 194 * several seconds worth of count. 195 * 196 * WARNING! callouts can preempt normal threads. However, they will not 197 * preempt a thread holding a spinlock so we *can* safely use spinlocks. 198 */ 199 static int schedcpu_stats(struct proc *p, void *data __unused); 200 static int schedcpu_resource(struct proc *p, void *data __unused); 201 202 static void 203 schedcpu(void *arg) 204 { 205 allproc_scan(schedcpu_stats, NULL, 1); 206 allproc_scan(schedcpu_resource, NULL, 1); 207 if (mycpu->gd_cpuid == 0) { 208 wakeup((caddr_t)&lbolt); 209 wakeup(lbolt_syncer); 210 } 211 callout_reset(&mycpu->gd_schedcpu_callout, hz, schedcpu, NULL); 212 } 213 214 /* 215 * General process statistics once a second 216 */ 217 static int 218 schedcpu_stats(struct proc *p, void *data __unused) 219 { 220 struct lwp *lp; 221 222 /* 223 * Threads may not be completely set up if process in SIDL state. 224 */ 225 if (p->p_stat == SIDL) 226 return(0); 227 228 PHOLD(p); 229 if (lwkt_trytoken(&p->p_token) == FALSE) { 230 PRELE(p); 231 return(0); 232 } 233 234 p->p_swtime++; 235 FOREACH_LWP_IN_PROC(lp, p) { 236 if (lp->lwp_stat == LSSLEEP) { 237 ++lp->lwp_slptime; 238 if (lp->lwp_slptime == 1) 239 p->p_usched->uload_update(lp); 240 } 241 242 /* 243 * Only recalculate processes that are active or have slept 244 * less then 2 seconds. The schedulers understand this. 245 * Otherwise decay by 50% per second. 246 */ 247 if (lp->lwp_slptime <= 1) { 248 p->p_usched->recalculate(lp); 249 } else { 250 int decay; 251 252 decay = pctcpu_decay; 253 cpu_ccfence(); 254 if (decay <= 1) 255 decay = 1; 256 if (decay > 100) 257 decay = 100; 258 lp->lwp_pctcpu = (lp->lwp_pctcpu * (decay - 1)) / decay; 259 } 260 } 261 lwkt_reltoken(&p->p_token); 262 lwkt_yield(); 263 PRELE(p); 264 return(0); 265 } 266 267 /* 268 * Resource checks. XXX break out since ksignal/killproc can block, 269 * limiting us to one process killed per second. There is probably 270 * a better way. 271 */ 272 static int 273 schedcpu_resource(struct proc *p, void *data __unused) 274 { 275 u_int64_t ttime; 276 struct lwp *lp; 277 278 if (p->p_stat == SIDL) 279 return(0); 280 281 PHOLD(p); 282 if (lwkt_trytoken(&p->p_token) == FALSE) { 283 PRELE(p); 284 return(0); 285 } 286 287 if (p->p_stat == SZOMB || p->p_limit == NULL) { 288 lwkt_reltoken(&p->p_token); 289 PRELE(p); 290 return(0); 291 } 292 293 ttime = 0; 294 FOREACH_LWP_IN_PROC(lp, p) { 295 /* 296 * We may have caught an lp in the middle of being 297 * created, lwp_thread can be NULL. 298 */ 299 if (lp->lwp_thread) { 300 ttime += lp->lwp_thread->td_sticks; 301 ttime += lp->lwp_thread->td_uticks; 302 } 303 } 304 305 switch(plimit_testcpulimit(p, ttime)) { 306 case PLIMIT_TESTCPU_KILL: 307 killproc(p, "exceeded maximum CPU limit"); 308 break; 309 case PLIMIT_TESTCPU_XCPU: 310 if ((p->p_flags & P_XCPU) == 0) { 311 p->p_flags |= P_XCPU; 312 ksignal(p, SIGXCPU); 313 } 314 break; 315 default: 316 break; 317 } 318 lwkt_reltoken(&p->p_token); 319 lwkt_yield(); 320 PRELE(p); 321 return(0); 322 } 323 324 /* 325 * This is only used by ps. Generate a cpu percentage use over 326 * a period of one second. 327 */ 328 void 329 updatepcpu(struct lwp *lp, int cpticks, int ttlticks) 330 { 331 fixpt_t acc; 332 int remticks; 333 334 acc = (cpticks << FSHIFT) / ttlticks; 335 if (ttlticks >= ESTCPUFREQ) { 336 lp->lwp_pctcpu = acc; 337 } else { 338 remticks = ESTCPUFREQ - ttlticks; 339 lp->lwp_pctcpu = (acc * ttlticks + lp->lwp_pctcpu * remticks) / 340 ESTCPUFREQ; 341 } 342 } 343 344 /* 345 * Handy macros to calculate hash indices. LOOKUP() calculates the 346 * global cpumask hash index, TCHASHSHIFT() converts that into the 347 * pcpu hash index. 348 * 349 * By making the pcpu hash arrays smaller we save a significant amount 350 * of memory at very low cost. The real cost is in IPIs, which are handled 351 * by the much larger global cpumask hash table. 352 */ 353 #define LOOKUP_PRIME 66555444443333333ULL 354 #define LOOKUP(x) ((((uintptr_t)(x) + ((uintptr_t)(x) >> 18)) ^ \ 355 LOOKUP_PRIME) % slpque_tablesize) 356 #define TCHASHSHIFT(x) ((x) >> 4) 357 358 static uint32_t slpque_tablesize; 359 static cpumask_t *slpque_cpumasks; 360 361 SYSCTL_UINT(_kern, OID_AUTO, slpque_tablesize, CTLFLAG_RD, &slpque_tablesize, 362 0, ""); 363 364 /* 365 * This is a dandy function that allows us to interlock tsleep/wakeup 366 * operations with unspecified upper level locks, such as lockmgr locks, 367 * simply by holding a critical section. The sequence is: 368 * 369 * (acquire upper level lock) 370 * tsleep_interlock(blah) 371 * (release upper level lock) 372 * tsleep(blah, ...) 373 * 374 * Basically this functions queues us on the tsleep queue without actually 375 * descheduling us. When tsleep() is later called with PINTERLOCK it 376 * assumes the thread was already queued, otherwise it queues it there. 377 * 378 * Thus it is possible to receive the wakeup prior to going to sleep and 379 * the race conditions are covered. 380 */ 381 static __inline void 382 _tsleep_interlock(globaldata_t gd, const volatile void *ident, int flags) 383 { 384 thread_t td = gd->gd_curthread; 385 struct tslpque *qp; 386 uint32_t cid; 387 uint32_t gid; 388 389 if (ident == NULL) { 390 kprintf("tsleep_interlock: NULL ident %s\n", td->td_comm); 391 print_backtrace(5); 392 } 393 394 crit_enter_quick(td); 395 if (td->td_flags & TDF_TSLEEPQ) { 396 /* 397 * Shortcut if unchanged 398 */ 399 if (td->td_wchan == ident && 400 td->td_wdomain == (flags & PDOMAIN_MASK)) { 401 crit_exit_quick(td); 402 return; 403 } 404 405 /* 406 * Remove current sleepq 407 */ 408 cid = LOOKUP(td->td_wchan); 409 gid = TCHASHSHIFT(cid); 410 qp = &gd->gd_tsleep_hash[gid]; 411 TAILQ_REMOVE(&qp->queue, td, td_sleepq); 412 if (TAILQ_FIRST(&qp->queue) == NULL) { 413 qp->ident0 = NULL; 414 qp->ident1 = NULL; 415 qp->ident2 = NULL; 416 qp->ident3 = NULL; 417 ATOMIC_CPUMASK_NANDBIT(slpque_cpumasks[cid], 418 gd->gd_cpuid); 419 } 420 } else { 421 td->td_flags |= TDF_TSLEEPQ; 422 } 423 cid = LOOKUP(ident); 424 gid = TCHASHSHIFT(cid); 425 qp = &gd->gd_tsleep_hash[gid]; 426 TAILQ_INSERT_TAIL(&qp->queue, td, td_sleepq); 427 if (qp->ident0 != ident && qp->ident1 != ident && 428 qp->ident2 != ident && qp->ident3 != ident) { 429 if (qp->ident0 == NULL) 430 qp->ident0 = ident; 431 else if (qp->ident1 == NULL) 432 qp->ident1 = ident; 433 else if (qp->ident2 == NULL) 434 qp->ident2 = ident; 435 else if (qp->ident3 == NULL) 436 qp->ident3 = ident; 437 else 438 qp->ident0 = (void *)(intptr_t)-1; 439 } 440 ATOMIC_CPUMASK_ORBIT(slpque_cpumasks[cid], gd->gd_cpuid); 441 td->td_wchan = ident; 442 td->td_wdomain = flags & PDOMAIN_MASK; 443 crit_exit_quick(td); 444 } 445 446 void 447 tsleep_interlock(const volatile void *ident, int flags) 448 { 449 _tsleep_interlock(mycpu, ident, flags); 450 } 451 452 /* 453 * Remove thread from sleepq. Must be called with a critical section held. 454 * The thread must not be migrating. 455 */ 456 static __inline void 457 _tsleep_remove(thread_t td) 458 { 459 globaldata_t gd = mycpu; 460 struct tslpque *qp; 461 uint32_t cid; 462 uint32_t gid; 463 464 KKASSERT(td->td_gd == gd && IN_CRITICAL_SECT(td)); 465 KKASSERT((td->td_flags & TDF_MIGRATING) == 0); 466 if (td->td_flags & TDF_TSLEEPQ) { 467 td->td_flags &= ~TDF_TSLEEPQ; 468 cid = LOOKUP(td->td_wchan); 469 gid = TCHASHSHIFT(cid); 470 qp = &gd->gd_tsleep_hash[gid]; 471 TAILQ_REMOVE(&qp->queue, td, td_sleepq); 472 if (TAILQ_FIRST(&qp->queue) == NULL) { 473 ATOMIC_CPUMASK_NANDBIT(slpque_cpumasks[cid], 474 gd->gd_cpuid); 475 } 476 td->td_wchan = NULL; 477 td->td_wdomain = 0; 478 } 479 } 480 481 void 482 tsleep_remove(thread_t td) 483 { 484 _tsleep_remove(td); 485 } 486 487 /* 488 * General sleep call. Suspends the current process until a wakeup is 489 * performed on the specified identifier. The process will then be made 490 * runnable with the specified priority. Sleeps at most timo/hz seconds 491 * (0 means no timeout). If flags includes PCATCH flag, signals are checked 492 * before and after sleeping, else signals are not checked. Returns 0 if 493 * awakened, EWOULDBLOCK if the timeout expires. If PCATCH is set and a 494 * signal needs to be delivered, ERESTART is returned if the current system 495 * call should be restarted if possible, and EINTR is returned if the system 496 * call should be interrupted by the signal (return EINTR). 497 * 498 * Note that if we are a process, we release_curproc() before messing with 499 * the LWKT scheduler. 500 * 501 * During autoconfiguration or after a panic, a sleep will simply 502 * lower the priority briefly to allow interrupts, then return. 503 * 504 * WARNING! This code can't block (short of switching away), or bad things 505 * will happen. No getting tokens, no blocking locks, etc. 506 */ 507 int 508 tsleep(const volatile void *ident, int flags, const char *wmesg, int timo) 509 { 510 struct thread *td = curthread; 511 struct lwp *lp = td->td_lwp; 512 struct proc *p = td->td_proc; /* may be NULL */ 513 globaldata_t gd; 514 int sig; 515 int catch; 516 int error; 517 int oldpri; 518 struct callout thandle; 519 520 /* 521 * Currently a severe hack. Make sure any delayed wakeups 522 * are flushed before we sleep or we might deadlock on whatever 523 * event we are sleeping on. 524 */ 525 if (td->td_flags & TDF_DELAYED_WAKEUP) 526 wakeup_end_delayed(); 527 528 /* 529 * NOTE: removed KTRPOINT, it could cause races due to blocking 530 * even in stable. Just scrap it for now. 531 */ 532 if (!tsleep_crypto_dump && (tsleep_now_works == 0 || panicstr)) { 533 /* 534 * After a panic, or before we actually have an operational 535 * softclock, just give interrupts a chance, then just return; 536 * 537 * don't run any other procs or panic below, 538 * in case this is the idle process and already asleep. 539 */ 540 splz(); 541 oldpri = td->td_pri; 542 lwkt_setpri_self(safepri); 543 lwkt_switch(); 544 lwkt_setpri_self(oldpri); 545 return (0); 546 } 547 logtsleep2(tsleep_beg, ident); 548 gd = td->td_gd; 549 KKASSERT(td != &gd->gd_idlethread); /* you must be kidding! */ 550 551 /* 552 * NOTE: all of this occurs on the current cpu, including any 553 * callout-based wakeups, so a critical section is a sufficient 554 * interlock. 555 * 556 * The entire sequence through to where we actually sleep must 557 * run without breaking the critical section. 558 */ 559 catch = flags & PCATCH; 560 error = 0; 561 sig = 0; 562 563 crit_enter_quick(td); 564 565 KASSERT(ident != NULL, ("tsleep: no ident")); 566 KASSERT(lp == NULL || 567 lp->lwp_stat == LSRUN || /* Obvious */ 568 lp->lwp_stat == LSSTOP, /* Set in tstop */ 569 ("tsleep %p %s %d", 570 ident, wmesg, lp->lwp_stat)); 571 572 /* 573 * We interlock the sleep queue if the caller has not already done 574 * it for us. This must be done before we potentially acquire any 575 * tokens or we can loose the wakeup. 576 */ 577 if ((flags & PINTERLOCKED) == 0) { 578 _tsleep_interlock(gd, ident, flags); 579 } 580 581 /* 582 * Setup for the current process (if this is a process). We must 583 * interlock with lwp_token to avoid remote wakeup races via 584 * setrunnable() 585 */ 586 if (lp) { 587 lwkt_gettoken(&lp->lwp_token); 588 589 /* 590 * If the umbrella process is in the SCORE state then 591 * make sure that the thread is flagged going into a 592 * normal sleep to allow the core dump to proceed, otherwise 593 * the coredump can end up waiting forever. If the normal 594 * sleep is woken up, the thread will enter a stopped state 595 * upon return to userland. 596 * 597 * We do not want to interrupt or cause a thread exist at 598 * this juncture because that will mess-up the state the 599 * coredump is trying to save. 600 */ 601 if (p->p_stat == SCORE) { 602 lwkt_gettoken(&p->p_token); 603 if ((lp->lwp_mpflags & LWP_MP_WSTOP) == 0) { 604 atomic_set_int(&lp->lwp_mpflags, LWP_MP_WSTOP); 605 ++p->p_nstopped; 606 } 607 lwkt_reltoken(&p->p_token); 608 } 609 610 /* 611 * PCATCH requested. 612 */ 613 if (catch) { 614 /* 615 * Early termination if PCATCH was set and a 616 * signal is pending, interlocked with the 617 * critical section. 618 * 619 * Early termination only occurs when tsleep() is 620 * entered while in a normal LSRUN state. 621 */ 622 if ((sig = CURSIG(lp)) != 0) 623 goto resume; 624 625 /* 626 * Causes ksignal to wake us up if a signal is 627 * received (interlocked with lp->lwp_token). 628 */ 629 lp->lwp_flags |= LWP_SINTR; 630 } 631 } else { 632 KKASSERT(p == NULL); 633 } 634 635 /* 636 * Make sure the current process has been untangled from 637 * the userland scheduler and initialize slptime to start 638 * counting. 639 * 640 * NOTE: td->td_wakefromcpu is pre-set by the release function 641 * for the dfly scheduler, and then adjusted by _wakeup() 642 */ 643 if (lp) { 644 p->p_usched->release_curproc(lp); 645 lp->lwp_slptime = 0; 646 } 647 648 /* 649 * For PINTERLOCKED operation, TDF_TSLEEPQ might not be set if 650 * a wakeup() was processed before the thread could go to sleep. 651 * 652 * If TDF_TSLEEPQ is set, make sure the ident matches the recorded 653 * ident. If it does not then the thread slept inbetween the 654 * caller's initial tsleep_interlock() call and the caller's tsleep() 655 * call. 656 * 657 * Extreme loads can cause the sending of an IPI (e.g. wakeup()'s) 658 * to process incoming IPIs, thus draining incoming wakeups. 659 */ 660 if ((td->td_flags & TDF_TSLEEPQ) == 0) { 661 logtsleep2(ilockfail, ident); 662 goto resume; 663 } else if (td->td_wchan != ident || 664 td->td_wdomain != (flags & PDOMAIN_MASK)) { 665 logtsleep2(ilockfail, ident); 666 goto resume; 667 } 668 669 /* 670 * scheduling is blocked while in a critical section. Coincide 671 * the descheduled-by-tsleep flag with the descheduling of the 672 * lwkt. 673 * 674 * The timer callout is localized on our cpu and interlocked by 675 * our critical section. 676 */ 677 lwkt_deschedule_self(td); 678 td->td_flags |= TDF_TSLEEP_DESCHEDULED; 679 td->td_wmesg = wmesg; 680 681 /* 682 * Setup the timeout, if any. The timeout is only operable while 683 * the thread is flagged descheduled. 684 */ 685 KKASSERT((td->td_flags & TDF_TIMEOUT) == 0); 686 if (timo) { 687 callout_init_mp(&thandle); 688 callout_reset(&thandle, timo, endtsleep, td); 689 } 690 691 /* 692 * Beddy bye bye. 693 */ 694 if (lp) { 695 /* 696 * Ok, we are sleeping. Place us in the SSLEEP state. 697 */ 698 KKASSERT((lp->lwp_mpflags & LWP_MP_ONRUNQ) == 0); 699 700 /* 701 * tstop() sets LSSTOP, so don't fiddle with that. 702 */ 703 if (lp->lwp_stat != LSSTOP) 704 lp->lwp_stat = LSSLEEP; 705 lp->lwp_ru.ru_nvcsw++; 706 p->p_usched->uload_update(lp); 707 lwkt_switch(); 708 709 /* 710 * And when we are woken up, put us back in LSRUN. If we 711 * slept for over a second, recalculate our estcpu. 712 */ 713 lp->lwp_stat = LSRUN; 714 if (lp->lwp_slptime) { 715 p->p_usched->uload_update(lp); 716 p->p_usched->recalculate(lp); 717 } 718 lp->lwp_slptime = 0; 719 } else { 720 lwkt_switch(); 721 } 722 723 /* 724 * Make sure we haven't switched cpus while we were asleep. It's 725 * not supposed to happen. Cleanup our temporary flags. 726 */ 727 KKASSERT(gd == td->td_gd); 728 729 /* 730 * Cleanup the timeout. If the timeout has already occured thandle 731 * has already been stopped, otherwise stop thandle. If the timeout 732 * is running (the callout thread must be blocked trying to get 733 * lwp_token) then wait for us to get scheduled. 734 */ 735 if (timo) { 736 while (td->td_flags & TDF_TIMEOUT_RUNNING) { 737 /* else we won't get rescheduled! */ 738 if (lp->lwp_stat != LSSTOP) 739 lp->lwp_stat = LSSLEEP; 740 lwkt_deschedule_self(td); 741 td->td_wmesg = "tsrace"; 742 lwkt_switch(); 743 kprintf("td %p %s: timeout race\n", td, td->td_comm); 744 } 745 if (td->td_flags & TDF_TIMEOUT) { 746 td->td_flags &= ~TDF_TIMEOUT; 747 error = EWOULDBLOCK; 748 } else { 749 /* does not block when on same cpu */ 750 callout_cancel(&thandle); 751 } 752 } 753 td->td_flags &= ~TDF_TSLEEP_DESCHEDULED; 754 755 /* 756 * Make sure we have been removed from the sleepq. In most 757 * cases this will have been done for us already but it is 758 * possible for a scheduling IPI to be in-flight from a 759 * previous tsleep/tsleep_interlock() or due to a straight-out 760 * call to lwkt_schedule() (in the case of an interrupt thread), 761 * causing a spurious wakeup. 762 */ 763 _tsleep_remove(td); 764 td->td_wmesg = NULL; 765 766 /* 767 * Figure out the correct error return. If interrupted by a 768 * signal we want to return EINTR or ERESTART. 769 */ 770 resume: 771 if (lp) { 772 if (catch && error == 0) { 773 if (sig != 0 || (sig = CURSIG(lp))) { 774 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig)) 775 error = EINTR; 776 else 777 error = ERESTART; 778 } 779 } 780 781 lp->lwp_flags &= ~LWP_SINTR; 782 783 /* 784 * Unconditionally set us to LSRUN on resume. lwp_stat could 785 * be in a weird state due to the goto resume, particularly 786 * when tsleep() is called from tstop(). 787 */ 788 lp->lwp_stat = LSRUN; 789 lwkt_reltoken(&lp->lwp_token); 790 } 791 logtsleep1(tsleep_end); 792 crit_exit_quick(td); 793 794 return (error); 795 } 796 797 /* 798 * Interlocked spinlock sleep. An exclusively held spinlock must 799 * be passed to ssleep(). The function will atomically release the 800 * spinlock and tsleep on the ident, then reacquire the spinlock and 801 * return. 802 * 803 * This routine is fairly important along the critical path, so optimize it 804 * heavily. 805 */ 806 int 807 ssleep(const volatile void *ident, struct spinlock *spin, int flags, 808 const char *wmesg, int timo) 809 { 810 globaldata_t gd = mycpu; 811 int error; 812 813 _tsleep_interlock(gd, ident, flags); 814 spin_unlock_quick(gd, spin); 815 error = tsleep(ident, flags | PINTERLOCKED, wmesg, timo); 816 KKASSERT(gd == mycpu); 817 _spin_lock_quick(gd, spin, wmesg); 818 819 return (error); 820 } 821 822 int 823 lksleep(const volatile void *ident, struct lock *lock, int flags, 824 const char *wmesg, int timo) 825 { 826 globaldata_t gd = mycpu; 827 int error; 828 829 _tsleep_interlock(gd, ident, flags); 830 lockmgr(lock, LK_RELEASE); 831 error = tsleep(ident, flags | PINTERLOCKED, wmesg, timo); 832 lockmgr(lock, LK_EXCLUSIVE); 833 834 return (error); 835 } 836 837 /* 838 * Interlocked mutex sleep. An exclusively held mutex must be passed 839 * to mtxsleep(). The function will atomically release the mutex 840 * and tsleep on the ident, then reacquire the mutex and return. 841 */ 842 int 843 mtxsleep(const volatile void *ident, struct mtx *mtx, int flags, 844 const char *wmesg, int timo) 845 { 846 globaldata_t gd = mycpu; 847 int error; 848 849 _tsleep_interlock(gd, ident, flags); 850 mtx_unlock(mtx); 851 error = tsleep(ident, flags | PINTERLOCKED, wmesg, timo); 852 mtx_lock_ex_quick(mtx); 853 854 return (error); 855 } 856 857 /* 858 * Interlocked serializer sleep. An exclusively held serializer must 859 * be passed to zsleep(). The function will atomically release 860 * the serializer and tsleep on the ident, then reacquire the serializer 861 * and return. 862 */ 863 int 864 zsleep(const volatile void *ident, struct lwkt_serialize *slz, int flags, 865 const char *wmesg, int timo) 866 { 867 globaldata_t gd = mycpu; 868 int ret; 869 870 ASSERT_SERIALIZED(slz); 871 872 _tsleep_interlock(gd, ident, flags); 873 lwkt_serialize_exit(slz); 874 ret = tsleep(ident, flags | PINTERLOCKED, wmesg, timo); 875 lwkt_serialize_enter(slz); 876 877 return ret; 878 } 879 880 /* 881 * Directly block on the LWKT thread by descheduling it. This 882 * is much faster then tsleep(), but the only legal way to wake 883 * us up is to directly schedule the thread. 884 * 885 * Setting TDF_SINTR will cause new signals to directly schedule us. 886 * 887 * This routine must be called while in a critical section. 888 */ 889 int 890 lwkt_sleep(const char *wmesg, int flags) 891 { 892 thread_t td = curthread; 893 int sig; 894 895 if ((flags & PCATCH) == 0 || td->td_lwp == NULL) { 896 td->td_flags |= TDF_BLOCKED; 897 td->td_wmesg = wmesg; 898 lwkt_deschedule_self(td); 899 lwkt_switch(); 900 td->td_wmesg = NULL; 901 td->td_flags &= ~TDF_BLOCKED; 902 return(0); 903 } 904 if ((sig = CURSIG(td->td_lwp)) != 0) { 905 if (SIGISMEMBER(td->td_proc->p_sigacts->ps_sigintr, sig)) 906 return(EINTR); 907 else 908 return(ERESTART); 909 910 } 911 td->td_flags |= TDF_BLOCKED | TDF_SINTR; 912 td->td_wmesg = wmesg; 913 lwkt_deschedule_self(td); 914 lwkt_switch(); 915 td->td_flags &= ~(TDF_BLOCKED | TDF_SINTR); 916 td->td_wmesg = NULL; 917 return(0); 918 } 919 920 /* 921 * Implement the timeout for tsleep. 922 * 923 * This type of callout timeout is scheduled on the same cpu the process 924 * is sleeping on. Also, at the moment, the MP lock is held. 925 */ 926 static void 927 endtsleep(void *arg) 928 { 929 thread_t td = arg; 930 struct lwp *lp; 931 932 /* 933 * We are going to have to get the lwp_token, which means we might 934 * block. This can race a tsleep getting woken up by other means 935 * so set TDF_TIMEOUT_RUNNING to force the tsleep to wait for our 936 * processing to complete (sorry tsleep!). 937 * 938 * We can safely set td_flags because td MUST be on the same cpu 939 * as we are. 940 */ 941 KKASSERT(td->td_gd == mycpu); 942 crit_enter(); 943 td->td_flags |= TDF_TIMEOUT_RUNNING | TDF_TIMEOUT; 944 945 /* 946 * This can block but TDF_TIMEOUT_RUNNING will prevent the thread 947 * from exiting the tsleep on us. The flag is interlocked by virtue 948 * of lp being on the same cpu as we are. 949 */ 950 if ((lp = td->td_lwp) != NULL) 951 lwkt_gettoken(&lp->lwp_token); 952 953 KKASSERT(td->td_flags & TDF_TSLEEP_DESCHEDULED); 954 955 if (lp) { 956 /* 957 * callout timer should normally never be set in tstop() 958 * because it passes a timeout of 0. However, there is a 959 * case during thread exit (which SSTOP's all the threads) 960 * for which tstop() must break out and can (properly) leave 961 * the thread in LSSTOP. 962 */ 963 KKASSERT(lp->lwp_stat != LSSTOP || 964 (lp->lwp_mpflags & LWP_MP_WEXIT)); 965 setrunnable(lp); 966 lwkt_reltoken(&lp->lwp_token); 967 } else { 968 _tsleep_remove(td); 969 lwkt_schedule(td); 970 } 971 KKASSERT(td->td_gd == mycpu); 972 td->td_flags &= ~TDF_TIMEOUT_RUNNING; 973 crit_exit(); 974 } 975 976 /* 977 * Make all processes sleeping on the specified identifier runnable. 978 * count may be zero or one only. 979 * 980 * The domain encodes the sleep/wakeup domain, flags, plus the originating 981 * cpu. 982 * 983 * This call may run without the MP lock held. We can only manipulate thread 984 * state on the cpu owning the thread. We CANNOT manipulate process state 985 * at all. 986 * 987 * _wakeup() can be passed to an IPI so we can't use (const volatile 988 * void *ident). 989 */ 990 static void 991 _wakeup(void *ident, int domain) 992 { 993 struct tslpque *qp; 994 struct thread *td; 995 struct thread *ntd; 996 globaldata_t gd; 997 cpumask_t mask; 998 uint32_t cid; 999 uint32_t gid; 1000 int wids = 0; 1001 1002 crit_enter(); 1003 logtsleep2(wakeup_beg, ident); 1004 gd = mycpu; 1005 cid = LOOKUP(ident); 1006 gid = TCHASHSHIFT(cid); 1007 qp = &gd->gd_tsleep_hash[gid]; 1008 restart: 1009 for (td = TAILQ_FIRST(&qp->queue); td != NULL; td = ntd) { 1010 ntd = TAILQ_NEXT(td, td_sleepq); 1011 if (td->td_wchan == ident && 1012 td->td_wdomain == (domain & PDOMAIN_MASK) 1013 ) { 1014 KKASSERT(td->td_gd == gd); 1015 _tsleep_remove(td); 1016 td->td_wakefromcpu = PWAKEUP_DECODE(domain); 1017 if (td->td_flags & TDF_TSLEEP_DESCHEDULED) { 1018 lwkt_schedule(td); 1019 if (domain & PWAKEUP_ONE) 1020 goto done; 1021 } 1022 goto restart; 1023 } 1024 if (td->td_wchan == qp->ident0) 1025 wids |= 1; 1026 else if (td->td_wchan == qp->ident1) 1027 wids |= 2; 1028 else if (td->td_wchan == qp->ident2) 1029 wids |= 4; 1030 else if (td->td_wchan == qp->ident3) 1031 wids |= 8; 1032 else 1033 wids |= 16; /* force ident0 to be retained (-1) */ 1034 } 1035 1036 /* 1037 * Because a bunch of cpumask array entries cover the same queue, it 1038 * is possible for our bit to remain set in some of them and cause 1039 * spurious wakeup IPIs later on. Make sure that the bit is cleared 1040 * when a spurious IPI occurs to prevent further spurious IPIs. 1041 */ 1042 if (TAILQ_FIRST(&qp->queue) == NULL) { 1043 ATOMIC_CPUMASK_NANDBIT(slpque_cpumasks[cid], gd->gd_cpuid); 1044 qp->ident0 = NULL; 1045 qp->ident1 = NULL; 1046 qp->ident2 = NULL; 1047 qp->ident3 = NULL; 1048 } else { 1049 if ((wids & 1) == 0) { 1050 if ((wids & 16) == 0) { 1051 qp->ident0 = NULL; 1052 } else { 1053 KKASSERT(qp->ident0 == (void *)(intptr_t)-1); 1054 } 1055 } 1056 if ((wids & 2) == 0) 1057 qp->ident1 = NULL; 1058 if ((wids & 4) == 0) 1059 qp->ident2 = NULL; 1060 if ((wids & 8) == 0) 1061 qp->ident3 = NULL; 1062 } 1063 1064 /* 1065 * We finished checking the current cpu but there still may be 1066 * more work to do. Either wakeup_one was requested and no matching 1067 * thread was found, or a normal wakeup was requested and we have 1068 * to continue checking cpus. 1069 * 1070 * It should be noted that this scheme is actually less expensive then 1071 * the old scheme when waking up multiple threads, since we send 1072 * only one IPI message per target candidate which may then schedule 1073 * multiple threads. Before we could have wound up sending an IPI 1074 * message for each thread on the target cpu (!= current cpu) that 1075 * needed to be woken up. 1076 * 1077 * NOTE: Wakeups occuring on remote cpus are asynchronous. This 1078 * should be ok since we are passing idents in the IPI rather 1079 * then thread pointers. 1080 * 1081 * NOTE: We MUST mfence (or use an atomic op) prior to reading 1082 * the cpumask, as another cpu may have written to it in 1083 * a fashion interlocked with whatever the caller did before 1084 * calling wakeup(). Otherwise we might miss the interaction 1085 * (kern_mutex.c can cause this problem). 1086 * 1087 * lfence is insufficient as it may allow a written state to 1088 * reorder around the cpumask load. 1089 */ 1090 if ((domain & PWAKEUP_MYCPU) == 0) { 1091 globaldata_t tgd; 1092 const volatile void *id0; 1093 int n; 1094 1095 cpu_mfence(); 1096 /* cpu_lfence(); */ 1097 mask = slpque_cpumasks[cid]; 1098 CPUMASK_ANDMASK(mask, gd->gd_other_cpus); 1099 while (CPUMASK_TESTNZERO(mask)) { 1100 n = BSRCPUMASK(mask); 1101 CPUMASK_NANDBIT(mask, n); 1102 tgd = globaldata_find(n); 1103 1104 /* 1105 * Both ident0 compares must from a single load 1106 * to avoid ident0 update races crossing the two 1107 * compares. 1108 */ 1109 qp = &tgd->gd_tsleep_hash[gid]; 1110 id0 = qp->ident0; 1111 cpu_ccfence(); 1112 if (id0 == (void *)(intptr_t)-1) { 1113 lwkt_send_ipiq2(tgd, _wakeup, ident, 1114 domain | PWAKEUP_MYCPU); 1115 ++tgd->gd_cnt.v_wakeup_colls; 1116 } else if (id0 == ident || 1117 qp->ident1 == ident || 1118 qp->ident2 == ident || 1119 qp->ident3 == ident) { 1120 lwkt_send_ipiq2(tgd, _wakeup, ident, 1121 domain | PWAKEUP_MYCPU); 1122 } 1123 } 1124 #if 0 1125 if (CPUMASK_TESTNZERO(mask)) { 1126 lwkt_send_ipiq2_mask(mask, _wakeup, ident, 1127 domain | PWAKEUP_MYCPU); 1128 } 1129 #endif 1130 } 1131 done: 1132 logtsleep1(wakeup_end); 1133 crit_exit(); 1134 } 1135 1136 /* 1137 * Wakeup all threads tsleep()ing on the specified ident, on all cpus 1138 */ 1139 void 1140 wakeup(const volatile void *ident) 1141 { 1142 globaldata_t gd = mycpu; 1143 thread_t td = gd->gd_curthread; 1144 1145 if (td && (td->td_flags & TDF_DELAYED_WAKEUP)) { 1146 /* 1147 * If we are in a delayed wakeup section, record up to two wakeups in 1148 * a per-CPU queue and issue them when we block or exit the delayed 1149 * wakeup section. 1150 */ 1151 if (atomic_cmpset_ptr(&gd->gd_delayed_wakeup[0], NULL, ident)) 1152 return; 1153 if (atomic_cmpset_ptr(&gd->gd_delayed_wakeup[1], NULL, ident)) 1154 return; 1155 1156 ident = atomic_swap_ptr(__DEQUALIFY(volatile void **, &gd->gd_delayed_wakeup[1]), 1157 __DEALL(ident)); 1158 ident = atomic_swap_ptr(__DEQUALIFY(volatile void **, &gd->gd_delayed_wakeup[0]), 1159 __DEALL(ident)); 1160 } 1161 1162 _wakeup(__DEALL(ident), PWAKEUP_ENCODE(0, gd->gd_cpuid)); 1163 } 1164 1165 /* 1166 * Wakeup one thread tsleep()ing on the specified ident, on any cpu. 1167 */ 1168 void 1169 wakeup_one(const volatile void *ident) 1170 { 1171 /* XXX potentially round-robin the first responding cpu */ 1172 _wakeup(__DEALL(ident), PWAKEUP_ENCODE(0, mycpu->gd_cpuid) | 1173 PWAKEUP_ONE); 1174 } 1175 1176 /* 1177 * Wakeup threads tsleep()ing on the specified ident on the current cpu 1178 * only. 1179 */ 1180 void 1181 wakeup_mycpu(const volatile void *ident) 1182 { 1183 _wakeup(__DEALL(ident), PWAKEUP_ENCODE(0, mycpu->gd_cpuid) | 1184 PWAKEUP_MYCPU); 1185 } 1186 1187 /* 1188 * Wakeup one thread tsleep()ing on the specified ident on the current cpu 1189 * only. 1190 */ 1191 void 1192 wakeup_mycpu_one(const volatile void *ident) 1193 { 1194 /* XXX potentially round-robin the first responding cpu */ 1195 _wakeup(__DEALL(ident), PWAKEUP_ENCODE(0, mycpu->gd_cpuid) | 1196 PWAKEUP_MYCPU | PWAKEUP_ONE); 1197 } 1198 1199 /* 1200 * Wakeup all thread tsleep()ing on the specified ident on the specified cpu 1201 * only. 1202 */ 1203 void 1204 wakeup_oncpu(globaldata_t gd, const volatile void *ident) 1205 { 1206 globaldata_t mygd = mycpu; 1207 if (gd == mycpu) { 1208 _wakeup(__DEALL(ident), PWAKEUP_ENCODE(0, mygd->gd_cpuid) | 1209 PWAKEUP_MYCPU); 1210 } else { 1211 lwkt_send_ipiq2(gd, _wakeup, __DEALL(ident), 1212 PWAKEUP_ENCODE(0, mygd->gd_cpuid) | 1213 PWAKEUP_MYCPU); 1214 } 1215 } 1216 1217 /* 1218 * Wakeup one thread tsleep()ing on the specified ident on the specified cpu 1219 * only. 1220 */ 1221 void 1222 wakeup_oncpu_one(globaldata_t gd, const volatile void *ident) 1223 { 1224 globaldata_t mygd = mycpu; 1225 if (gd == mygd) { 1226 _wakeup(__DEALL(ident), PWAKEUP_ENCODE(0, mygd->gd_cpuid) | 1227 PWAKEUP_MYCPU | PWAKEUP_ONE); 1228 } else { 1229 lwkt_send_ipiq2(gd, _wakeup, __DEALL(ident), 1230 PWAKEUP_ENCODE(0, mygd->gd_cpuid) | 1231 PWAKEUP_MYCPU | PWAKEUP_ONE); 1232 } 1233 } 1234 1235 /* 1236 * Wakeup all threads waiting on the specified ident that slept using 1237 * the specified domain, on all cpus. 1238 */ 1239 void 1240 wakeup_domain(const volatile void *ident, int domain) 1241 { 1242 _wakeup(__DEALL(ident), PWAKEUP_ENCODE(domain, mycpu->gd_cpuid)); 1243 } 1244 1245 /* 1246 * Wakeup one thread waiting on the specified ident that slept using 1247 * the specified domain, on any cpu. 1248 */ 1249 void 1250 wakeup_domain_one(const volatile void *ident, int domain) 1251 { 1252 /* XXX potentially round-robin the first responding cpu */ 1253 _wakeup(__DEALL(ident), 1254 PWAKEUP_ENCODE(domain, mycpu->gd_cpuid) | PWAKEUP_ONE); 1255 } 1256 1257 void 1258 wakeup_start_delayed(void) 1259 { 1260 globaldata_t gd = mycpu; 1261 1262 crit_enter(); 1263 gd->gd_curthread->td_flags |= TDF_DELAYED_WAKEUP; 1264 crit_exit(); 1265 } 1266 1267 void 1268 wakeup_end_delayed(void) 1269 { 1270 globaldata_t gd = mycpu; 1271 1272 if (gd->gd_curthread->td_flags & TDF_DELAYED_WAKEUP) { 1273 crit_enter(); 1274 gd->gd_curthread->td_flags &= ~TDF_DELAYED_WAKEUP; 1275 if (gd->gd_delayed_wakeup[0] || gd->gd_delayed_wakeup[1]) { 1276 if (gd->gd_delayed_wakeup[0]) { 1277 wakeup(gd->gd_delayed_wakeup[0]); 1278 gd->gd_delayed_wakeup[0] = NULL; 1279 } 1280 if (gd->gd_delayed_wakeup[1]) { 1281 wakeup(gd->gd_delayed_wakeup[1]); 1282 gd->gd_delayed_wakeup[1] = NULL; 1283 } 1284 } 1285 crit_exit(); 1286 } 1287 } 1288 1289 /* 1290 * setrunnable() 1291 * 1292 * Make a process runnable. lp->lwp_token must be held on call and this 1293 * function must be called from the cpu owning lp. 1294 * 1295 * This only has an effect if we are in LSSTOP or LSSLEEP. 1296 */ 1297 void 1298 setrunnable(struct lwp *lp) 1299 { 1300 thread_t td = lp->lwp_thread; 1301 1302 ASSERT_LWKT_TOKEN_HELD(&lp->lwp_token); 1303 KKASSERT(td->td_gd == mycpu); 1304 crit_enter(); 1305 if (lp->lwp_stat == LSSTOP) 1306 lp->lwp_stat = LSSLEEP; 1307 if (lp->lwp_stat == LSSLEEP) { 1308 _tsleep_remove(td); 1309 lwkt_schedule(td); 1310 } else if (td->td_flags & TDF_SINTR) { 1311 lwkt_schedule(td); 1312 } 1313 crit_exit(); 1314 } 1315 1316 /* 1317 * The process is stopped due to some condition, usually because p_stat is 1318 * set to SSTOP, but also possibly due to being traced. 1319 * 1320 * Caller must hold p->p_token 1321 * 1322 * NOTE! If the caller sets SSTOP, the caller must also clear P_WAITED 1323 * because the parent may check the child's status before the child actually 1324 * gets to this routine. 1325 * 1326 * This routine is called with the current lwp only, typically just 1327 * before returning to userland if the process state is detected as 1328 * possibly being in a stopped state. 1329 */ 1330 void 1331 tstop(void) 1332 { 1333 struct lwp *lp = curthread->td_lwp; 1334 struct proc *p = lp->lwp_proc; 1335 struct proc *q; 1336 1337 lwkt_gettoken(&lp->lwp_token); 1338 crit_enter(); 1339 1340 /* 1341 * If LWP_MP_WSTOP is set, we were sleeping 1342 * while our process was stopped. At this point 1343 * we were already counted as stopped. 1344 */ 1345 if ((lp->lwp_mpflags & LWP_MP_WSTOP) == 0) { 1346 /* 1347 * If we're the last thread to stop, signal 1348 * our parent. 1349 */ 1350 p->p_nstopped++; 1351 atomic_set_int(&lp->lwp_mpflags, LWP_MP_WSTOP); 1352 wakeup(&p->p_nstopped); 1353 if (p->p_nstopped == p->p_nthreads) { 1354 /* 1355 * Token required to interlock kern_wait() 1356 */ 1357 q = p->p_pptr; 1358 PHOLD(q); 1359 lwkt_gettoken(&q->p_token); 1360 p->p_flags &= ~P_WAITED; 1361 wakeup(p->p_pptr); 1362 if ((q->p_sigacts->ps_flag & PS_NOCLDSTOP) == 0) 1363 ksignal(q, SIGCHLD); 1364 lwkt_reltoken(&q->p_token); 1365 PRELE(q); 1366 } 1367 } 1368 1369 /* 1370 * Wait here while in a stopped state, interlocked with lwp_token. 1371 * We must break-out if the whole process is trying to exit. 1372 */ 1373 while (STOPLWP(p, lp)) { 1374 lp->lwp_stat = LSSTOP; 1375 tsleep(p, 0, "stop", 0); 1376 } 1377 p->p_nstopped--; 1378 atomic_clear_int(&lp->lwp_mpflags, LWP_MP_WSTOP); 1379 crit_exit(); 1380 lwkt_reltoken(&lp->lwp_token); 1381 } 1382 1383 /* 1384 * Compute a tenex style load average of a quantity on 1385 * 1, 5 and 15 minute intervals. This is a pcpu callout. 1386 * 1387 * We segment the lwp scan on a pcpu basis. This does NOT 1388 * mean the associated lwps are on this cpu, it is done 1389 * just to break the work up. 1390 * 1391 * The callout on cpu0 rolls up the stats from the other 1392 * cpus. 1393 */ 1394 static int loadav_count_runnable(struct lwp *p, void *data); 1395 1396 static void 1397 loadav(void *arg) 1398 { 1399 globaldata_t gd = mycpu; 1400 struct loadavg *avg; 1401 int i, nrun; 1402 1403 nrun = 0; 1404 alllwp_scan(loadav_count_runnable, &nrun, 1); 1405 gd->gd_loadav_nrunnable = nrun; 1406 if (gd->gd_cpuid == 0) { 1407 avg = &averunnable; 1408 nrun = 0; 1409 for (i = 0; i < ncpus; ++i) 1410 nrun += globaldata_find(i)->gd_loadav_nrunnable; 1411 for (i = 0; i < 3; i++) { 1412 avg->ldavg[i] = (cexp[i] * avg->ldavg[i] + 1413 (long)nrun * FSCALE * (FSCALE - cexp[i])) >> FSHIFT; 1414 } 1415 } 1416 1417 /* 1418 * Schedule the next update to occur after 5 seconds, but add a 1419 * random variation to avoid synchronisation with processes that 1420 * run at regular intervals. 1421 */ 1422 callout_reset(&gd->gd_loadav_callout, 1423 hz * 4 + (int)(krandom() % (hz * 2 + 1)), 1424 loadav, NULL); 1425 } 1426 1427 static int 1428 loadav_count_runnable(struct lwp *lp, void *data) 1429 { 1430 int *nrunp = data; 1431 thread_t td; 1432 1433 switch (lp->lwp_stat) { 1434 case LSRUN: 1435 if ((td = lp->lwp_thread) == NULL) 1436 break; 1437 if (td->td_flags & TDF_BLOCKED) 1438 break; 1439 ++*nrunp; 1440 break; 1441 default: 1442 break; 1443 } 1444 lwkt_yield(); 1445 return(0); 1446 } 1447 1448 /* 1449 * Regular data collection 1450 */ 1451 static uint64_t 1452 collect_load_callback(int n) 1453 { 1454 int fscale = averunnable.fscale; 1455 1456 return ((averunnable.ldavg[0] * 100 + (fscale >> 1)) / fscale); 1457 } 1458 1459 static void 1460 sched_setup(void *dummy __unused) 1461 { 1462 globaldata_t save_gd = mycpu; 1463 globaldata_t gd; 1464 int n; 1465 1466 kcollect_register(KCOLLECT_LOAD, "load", collect_load_callback, 1467 KCOLLECT_SCALE(KCOLLECT_LOAD_FORMAT, 0)); 1468 1469 /* 1470 * Kick off timeout driven events by calling first time. We 1471 * split the work across available cpus to help scale it, 1472 * it can eat a lot of cpu when there are a lot of processes 1473 * on the system. 1474 */ 1475 for (n = 0; n < ncpus; ++n) { 1476 gd = globaldata_find(n); 1477 lwkt_setcpu_self(gd); 1478 callout_init_mp(&gd->gd_loadav_callout); 1479 callout_init_mp(&gd->gd_schedcpu_callout); 1480 schedcpu(NULL); 1481 loadav(NULL); 1482 } 1483 lwkt_setcpu_self(save_gd); 1484 } 1485 1486 /* 1487 * Extremely early initialization, dummy-up the tables so we don't have 1488 * to conditionalize for NULL in _wakeup() and tsleep_interlock(). Even 1489 * though the system isn't blocking this early, these functions still 1490 * try to access the hash table. 1491 * 1492 * This setup will be overridden once sched_dyninit() -> sleep_gdinit() 1493 * is called. 1494 */ 1495 void 1496 sleep_early_gdinit(globaldata_t gd) 1497 { 1498 static struct tslpque dummy_slpque; 1499 static cpumask_t dummy_cpumasks; 1500 1501 slpque_tablesize = 1; 1502 gd->gd_tsleep_hash = &dummy_slpque; 1503 slpque_cpumasks = &dummy_cpumasks; 1504 TAILQ_INIT(&dummy_slpque.queue); 1505 } 1506 1507 /* 1508 * PCPU initialization. Called after KMALLOC is operational, by 1509 * sched_dyninit() for cpu 0, and by mi_gdinit() for other cpus later. 1510 * 1511 * WARNING! The pcpu hash table is smaller than the global cpumask 1512 * hash table, which can save us a lot of memory when maxproc 1513 * is set high. 1514 */ 1515 void 1516 sleep_gdinit(globaldata_t gd) 1517 { 1518 struct thread *td; 1519 size_t hash_size; 1520 uint32_t n; 1521 uint32_t i; 1522 1523 /* 1524 * This shouldn't happen, that is there shouldn't be any threads 1525 * waiting on the dummy tsleep queue this early in the boot. 1526 */ 1527 if (gd->gd_cpuid == 0) { 1528 struct tslpque *qp = &gd->gd_tsleep_hash[0]; 1529 TAILQ_FOREACH(td, &qp->queue, td_sleepq) { 1530 kprintf("SLEEP_GDINIT SWITCH %s\n", td->td_comm); 1531 } 1532 } 1533 1534 /* 1535 * Note that we have to allocate one extra slot because we are 1536 * shifting a modulo value. TCHASHSHIFT(slpque_tablesize - 1) can 1537 * return the same value as TCHASHSHIFT(slpque_tablesize). 1538 */ 1539 n = TCHASHSHIFT(slpque_tablesize) + 1; 1540 1541 hash_size = sizeof(struct tslpque) * n; 1542 gd->gd_tsleep_hash = (void *)kmem_alloc3(&kernel_map, hash_size, 1543 VM_SUBSYS_GD, 1544 KM_CPU(gd->gd_cpuid)); 1545 memset(gd->gd_tsleep_hash, 0, hash_size); 1546 for (i = 0; i < n; ++i) 1547 TAILQ_INIT(&gd->gd_tsleep_hash[i].queue); 1548 } 1549 1550 /* 1551 * Dynamic initialization after the memory system is operational. 1552 */ 1553 static void 1554 sched_dyninit(void *dummy __unused) 1555 { 1556 int tblsize; 1557 int tblsize2; 1558 int n; 1559 1560 /* 1561 * Calculate table size for slpque hash. We want a prime number 1562 * large enough to avoid overloading slpque_cpumasks when the 1563 * system has a large number of sleeping processes, which will 1564 * spam IPIs on wakeup(). 1565 * 1566 * While it is true this is really a per-lwp factor, generally 1567 * speaking the maxproc limit is a good metric to go by. 1568 */ 1569 for (tblsize = maxproc | 1; ; tblsize += 2) { 1570 if (tblsize % 3 == 0) 1571 continue; 1572 if (tblsize % 5 == 0) 1573 continue; 1574 tblsize2 = (tblsize / 2) | 1; 1575 for (n = 7; n < tblsize2; n += 2) { 1576 if (tblsize % n == 0) 1577 break; 1578 } 1579 if (n == tblsize2) 1580 break; 1581 } 1582 1583 /* 1584 * PIDs are currently limited to 6 digits. Cap the table size 1585 * at double this. 1586 */ 1587 if (tblsize > 2000003) 1588 tblsize = 2000003; 1589 1590 slpque_tablesize = tblsize; 1591 slpque_cpumasks = kmalloc(sizeof(*slpque_cpumasks) * slpque_tablesize, 1592 M_TSLEEP, M_WAITOK | M_ZERO); 1593 sleep_gdinit(mycpu); 1594 } 1595