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. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 * 38 * @(#)kern_synch.c 8.9 (Berkeley) 5/19/95 39 * $FreeBSD: src/sys/kern/kern_synch.c,v 1.87.2.6 2002/10/13 07:29:53 kbyanc Exp $ 40 * $DragonFly: src/sys/kern/kern_synch.c,v 1.90 2008/04/30 04:19:57 dillon Exp $ 41 */ 42 43 #include "opt_ktrace.h" 44 45 #include <sys/param.h> 46 #include <sys/systm.h> 47 #include <sys/proc.h> 48 #include <sys/kernel.h> 49 #include <sys/signalvar.h> 50 #include <sys/signal2.h> 51 #include <sys/resourcevar.h> 52 #include <sys/vmmeter.h> 53 #include <sys/sysctl.h> 54 #include <sys/lock.h> 55 #ifdef KTRACE 56 #include <sys/uio.h> 57 #include <sys/ktrace.h> 58 #endif 59 #include <sys/xwait.h> 60 #include <sys/ktr.h> 61 62 #include <sys/thread2.h> 63 #include <sys/spinlock2.h> 64 #include <sys/serialize.h> 65 66 #include <machine/cpu.h> 67 #include <machine/smp.h> 68 69 TAILQ_HEAD(tslpque, thread); 70 71 static void sched_setup (void *dummy); 72 SYSINIT(sched_setup, SI_SUB_KICK_SCHEDULER, SI_ORDER_FIRST, sched_setup, NULL) 73 74 int hogticks; 75 int lbolt; 76 int lbolt_syncer; 77 int sched_quantum; /* Roundrobin scheduling quantum in ticks. */ 78 int ncpus; 79 int ncpus2, ncpus2_shift, ncpus2_mask; 80 int ncpus_fit, ncpus_fit_mask; 81 int safepri; 82 int tsleep_now_works; 83 84 static struct callout loadav_callout; 85 static struct callout schedcpu_callout; 86 MALLOC_DEFINE(M_TSLEEP, "tslpque", "tsleep queues"); 87 88 #if !defined(KTR_TSLEEP) 89 #define KTR_TSLEEP KTR_ALL 90 #endif 91 KTR_INFO_MASTER(tsleep); 92 KTR_INFO(KTR_TSLEEP, tsleep, tsleep_beg, 0, "tsleep enter %p", sizeof(void *)); 93 KTR_INFO(KTR_TSLEEP, tsleep, tsleep_end, 1, "tsleep exit", 0); 94 KTR_INFO(KTR_TSLEEP, tsleep, wakeup_beg, 2, "wakeup enter %p", sizeof(void *)); 95 KTR_INFO(KTR_TSLEEP, tsleep, wakeup_end, 3, "wakeup exit", 0); 96 97 #define logtsleep1(name) KTR_LOG(tsleep_ ## name) 98 #define logtsleep2(name, val) KTR_LOG(tsleep_ ## name, val) 99 100 struct loadavg averunnable = 101 { {0, 0, 0}, FSCALE }; /* load average, of runnable procs */ 102 /* 103 * Constants for averages over 1, 5, and 15 minutes 104 * when sampling at 5 second intervals. 105 */ 106 static fixpt_t cexp[3] = { 107 0.9200444146293232 * FSCALE, /* exp(-1/12) */ 108 0.9834714538216174 * FSCALE, /* exp(-1/60) */ 109 0.9944598480048967 * FSCALE, /* exp(-1/180) */ 110 }; 111 112 static void endtsleep (void *); 113 static void unsleep_and_wakeup_thread(struct thread *td); 114 static void loadav (void *arg); 115 static void schedcpu (void *arg); 116 117 /* 118 * Adjust the scheduler quantum. The quantum is specified in microseconds. 119 * Note that 'tick' is in microseconds per tick. 120 */ 121 static int 122 sysctl_kern_quantum(SYSCTL_HANDLER_ARGS) 123 { 124 int error, new_val; 125 126 new_val = sched_quantum * tick; 127 error = sysctl_handle_int(oidp, &new_val, 0, req); 128 if (error != 0 || req->newptr == NULL) 129 return (error); 130 if (new_val < tick) 131 return (EINVAL); 132 sched_quantum = new_val / tick; 133 hogticks = 2 * sched_quantum; 134 return (0); 135 } 136 137 SYSCTL_PROC(_kern, OID_AUTO, quantum, CTLTYPE_INT|CTLFLAG_RW, 138 0, sizeof sched_quantum, sysctl_kern_quantum, "I", ""); 139 140 /* 141 * If `ccpu' is not equal to `exp(-1/20)' and you still want to use the 142 * faster/more-accurate formula, you'll have to estimate CCPU_SHIFT below 143 * and possibly adjust FSHIFT in "param.h" so that (FSHIFT >= CCPU_SHIFT). 144 * 145 * To estimate CCPU_SHIFT for exp(-1/20), the following formula was used: 146 * 1 - exp(-1/20) ~= 0.0487 ~= 0.0488 == 1 (fixed pt, *11* bits). 147 * 148 * If you don't want to bother with the faster/more-accurate formula, you 149 * can set CCPU_SHIFT to (FSHIFT + 1) which will use a slower/less-accurate 150 * (more general) method of calculating the %age of CPU used by a process. 151 * 152 * decay 95% of `lwp_pctcpu' in 60 seconds; see CCPU_SHIFT before changing 153 */ 154 #define CCPU_SHIFT 11 155 156 static fixpt_t ccpu = 0.95122942450071400909 * FSCALE; /* exp(-1/20) */ 157 SYSCTL_INT(_kern, OID_AUTO, ccpu, CTLFLAG_RD, &ccpu, 0, ""); 158 159 /* 160 * kernel uses `FSCALE', userland (SHOULD) use kern.fscale 161 */ 162 int fscale __unused = FSCALE; /* exported to systat */ 163 SYSCTL_INT(_kern, OID_AUTO, fscale, CTLFLAG_RD, 0, FSCALE, ""); 164 165 /* 166 * Recompute process priorities, once a second. 167 * 168 * Since the userland schedulers are typically event oriented, if the 169 * estcpu calculation at wakeup() time is not sufficient to make a 170 * process runnable relative to other processes in the system we have 171 * a 1-second recalc to help out. 172 * 173 * This code also allows us to store sysclock_t data in the process structure 174 * without fear of an overrun, since sysclock_t are guarenteed to hold 175 * several seconds worth of count. 176 * 177 * WARNING! callouts can preempt normal threads. However, they will not 178 * preempt a thread holding a spinlock so we *can* safely use spinlocks. 179 */ 180 static int schedcpu_stats(struct proc *p, void *data __unused); 181 static int schedcpu_resource(struct proc *p, void *data __unused); 182 183 static void 184 schedcpu(void *arg) 185 { 186 allproc_scan(schedcpu_stats, NULL); 187 allproc_scan(schedcpu_resource, NULL); 188 wakeup((caddr_t)&lbolt); 189 wakeup((caddr_t)&lbolt_syncer); 190 callout_reset(&schedcpu_callout, hz, schedcpu, NULL); 191 } 192 193 /* 194 * General process statistics once a second 195 */ 196 static int 197 schedcpu_stats(struct proc *p, void *data __unused) 198 { 199 struct lwp *lp; 200 201 crit_enter(); 202 p->p_swtime++; 203 FOREACH_LWP_IN_PROC(lp, p) { 204 if (lp->lwp_stat == LSSLEEP) 205 lp->lwp_slptime++; 206 207 /* 208 * Only recalculate processes that are active or have slept 209 * less then 2 seconds. The schedulers understand this. 210 */ 211 if (lp->lwp_slptime <= 1) { 212 p->p_usched->recalculate(lp); 213 } else { 214 lp->lwp_pctcpu = (lp->lwp_pctcpu * ccpu) >> FSHIFT; 215 } 216 } 217 crit_exit(); 218 return(0); 219 } 220 221 /* 222 * Resource checks. XXX break out since ksignal/killproc can block, 223 * limiting us to one process killed per second. There is probably 224 * a better way. 225 */ 226 static int 227 schedcpu_resource(struct proc *p, void *data __unused) 228 { 229 u_int64_t ttime; 230 struct lwp *lp; 231 232 crit_enter(); 233 if (p->p_stat == SIDL || 234 p->p_stat == SZOMB || 235 p->p_limit == NULL 236 ) { 237 crit_exit(); 238 return(0); 239 } 240 241 ttime = 0; 242 FOREACH_LWP_IN_PROC(lp, p) { 243 /* 244 * We may have caught an lp in the middle of being 245 * created, lwp_thread can be NULL. 246 */ 247 if (lp->lwp_thread) { 248 ttime += lp->lwp_thread->td_sticks; 249 ttime += lp->lwp_thread->td_uticks; 250 } 251 } 252 253 switch(plimit_testcpulimit(p->p_limit, ttime)) { 254 case PLIMIT_TESTCPU_KILL: 255 killproc(p, "exceeded maximum CPU limit"); 256 break; 257 case PLIMIT_TESTCPU_XCPU: 258 if ((p->p_flag & P_XCPU) == 0) { 259 p->p_flag |= P_XCPU; 260 ksignal(p, SIGXCPU); 261 } 262 break; 263 default: 264 break; 265 } 266 crit_exit(); 267 return(0); 268 } 269 270 /* 271 * This is only used by ps. Generate a cpu percentage use over 272 * a period of one second. 273 * 274 * MPSAFE 275 */ 276 void 277 updatepcpu(struct lwp *lp, int cpticks, int ttlticks) 278 { 279 fixpt_t acc; 280 int remticks; 281 282 acc = (cpticks << FSHIFT) / ttlticks; 283 if (ttlticks >= ESTCPUFREQ) { 284 lp->lwp_pctcpu = acc; 285 } else { 286 remticks = ESTCPUFREQ - ttlticks; 287 lp->lwp_pctcpu = (acc * ttlticks + lp->lwp_pctcpu * remticks) / 288 ESTCPUFREQ; 289 } 290 } 291 292 /* 293 * tsleep/wakeup hash table parameters. Try to find the sweet spot for 294 * like addresses being slept on. 295 */ 296 #define TABLESIZE 1024 297 #define LOOKUP(x) (((intptr_t)(x) >> 6) & (TABLESIZE - 1)) 298 299 static cpumask_t slpque_cpumasks[TABLESIZE]; 300 301 /* 302 * General scheduler initialization. We force a reschedule 25 times 303 * a second by default. Note that cpu0 is initialized in early boot and 304 * cannot make any high level calls. 305 * 306 * Each cpu has its own sleep queue. 307 */ 308 void 309 sleep_gdinit(globaldata_t gd) 310 { 311 static struct tslpque slpque_cpu0[TABLESIZE]; 312 int i; 313 314 if (gd->gd_cpuid == 0) { 315 sched_quantum = (hz + 24) / 25; 316 hogticks = 2 * sched_quantum; 317 318 gd->gd_tsleep_hash = slpque_cpu0; 319 } else { 320 gd->gd_tsleep_hash = kmalloc(sizeof(slpque_cpu0), 321 M_TSLEEP, M_WAITOK | M_ZERO); 322 } 323 for (i = 0; i < TABLESIZE; ++i) 324 TAILQ_INIT(&gd->gd_tsleep_hash[i]); 325 } 326 327 /* 328 * General sleep call. Suspends the current process until a wakeup is 329 * performed on the specified identifier. The process will then be made 330 * runnable with the specified priority. Sleeps at most timo/hz seconds 331 * (0 means no timeout). If flags includes PCATCH flag, signals are checked 332 * before and after sleeping, else signals are not checked. Returns 0 if 333 * awakened, EWOULDBLOCK if the timeout expires. If PCATCH is set and a 334 * signal needs to be delivered, ERESTART is returned if the current system 335 * call should be restarted if possible, and EINTR is returned if the system 336 * call should be interrupted by the signal (return EINTR). 337 * 338 * Note that if we are a process, we release_curproc() before messing with 339 * the LWKT scheduler. 340 * 341 * During autoconfiguration or after a panic, a sleep will simply 342 * lower the priority briefly to allow interrupts, then return. 343 */ 344 int 345 tsleep(void *ident, int flags, const char *wmesg, int timo) 346 { 347 struct thread *td = curthread; 348 struct lwp *lp = td->td_lwp; 349 struct proc *p = td->td_proc; /* may be NULL */ 350 globaldata_t gd; 351 int sig; 352 int catch; 353 int id; 354 int error; 355 int oldpri; 356 struct callout thandle; 357 358 /* 359 * NOTE: removed KTRPOINT, it could cause races due to blocking 360 * even in stable. Just scrap it for now. 361 */ 362 if (tsleep_now_works == 0 || panicstr) { 363 /* 364 * After a panic, or before we actually have an operational 365 * softclock, just give interrupts a chance, then just return; 366 * 367 * don't run any other procs or panic below, 368 * in case this is the idle process and already asleep. 369 */ 370 splz(); 371 oldpri = td->td_pri & TDPRI_MASK; 372 lwkt_setpri_self(safepri); 373 lwkt_switch(); 374 lwkt_setpri_self(oldpri); 375 return (0); 376 } 377 logtsleep2(tsleep_beg, ident); 378 gd = td->td_gd; 379 KKASSERT(td != &gd->gd_idlethread); /* you must be kidding! */ 380 381 /* 382 * NOTE: all of this occurs on the current cpu, including any 383 * callout-based wakeups, so a critical section is a sufficient 384 * interlock. 385 * 386 * The entire sequence through to where we actually sleep must 387 * run without breaking the critical section. 388 */ 389 id = LOOKUP(ident); 390 catch = flags & PCATCH; 391 error = 0; 392 sig = 0; 393 394 crit_enter_quick(td); 395 396 KASSERT(ident != NULL, ("tsleep: no ident")); 397 KASSERT(lp == NULL || 398 lp->lwp_stat == LSRUN || /* Obvious */ 399 lp->lwp_stat == LSSTOP, /* Set in tstop */ 400 ("tsleep %p %s %d", 401 ident, wmesg, lp->lwp_stat)); 402 403 /* 404 * Setup for the current process (if this is a process). 405 */ 406 if (lp) { 407 if (catch) { 408 /* 409 * Early termination if PCATCH was set and a 410 * signal is pending, interlocked with the 411 * critical section. 412 * 413 * Early termination only occurs when tsleep() is 414 * entered while in a normal LSRUN state. 415 */ 416 if ((sig = CURSIG(lp)) != 0) 417 goto resume; 418 419 /* 420 * Early termination if PCATCH was set and a 421 * mailbox signal was possibly delivered prior to 422 * the system call even being made, in order to 423 * allow the user to interlock without having to 424 * make additional system calls. 425 */ 426 if (p->p_flag & P_MAILBOX) 427 goto resume; 428 429 /* 430 * Causes ksignal to wake us up when. 431 */ 432 lp->lwp_flag |= LWP_SINTR; 433 } 434 435 /* 436 * Make sure the current process has been untangled from 437 * the userland scheduler and initialize slptime to start 438 * counting. 439 */ 440 if (flags & PNORESCHED) 441 td->td_flags |= TDF_NORESCHED; 442 p->p_usched->release_curproc(lp); 443 lp->lwp_slptime = 0; 444 } 445 446 /* 447 * Move our thread to the correct queue and setup our wchan, etc. 448 */ 449 lwkt_deschedule_self(td); 450 td->td_flags |= TDF_TSLEEPQ; 451 TAILQ_INSERT_TAIL(&gd->gd_tsleep_hash[id], td, td_threadq); 452 atomic_set_int(&slpque_cpumasks[id], gd->gd_cpumask); 453 454 td->td_wchan = ident; 455 td->td_wmesg = wmesg; 456 td->td_wdomain = flags & PDOMAIN_MASK; 457 458 /* 459 * Setup the timeout, if any 460 */ 461 if (timo) { 462 callout_init(&thandle); 463 callout_reset(&thandle, timo, endtsleep, td); 464 } 465 466 /* 467 * Beddy bye bye. 468 */ 469 if (lp) { 470 /* 471 * Ok, we are sleeping. Place us in the SSLEEP state. 472 */ 473 KKASSERT((lp->lwp_flag & LWP_ONRUNQ) == 0); 474 /* 475 * tstop() sets LSSTOP, so don't fiddle with that. 476 */ 477 if (lp->lwp_stat != LSSTOP) 478 lp->lwp_stat = LSSLEEP; 479 lp->lwp_ru.ru_nvcsw++; 480 lwkt_switch(); 481 482 /* 483 * And when we are woken up, put us back in LSRUN. If we 484 * slept for over a second, recalculate our estcpu. 485 */ 486 lp->lwp_stat = LSRUN; 487 if (lp->lwp_slptime) 488 p->p_usched->recalculate(lp); 489 lp->lwp_slptime = 0; 490 } else { 491 lwkt_switch(); 492 } 493 494 /* 495 * Make sure we haven't switched cpus while we were asleep. It's 496 * not supposed to happen. Cleanup our temporary flags. 497 */ 498 KKASSERT(gd == td->td_gd); 499 td->td_flags &= ~TDF_NORESCHED; 500 501 /* 502 * Cleanup the timeout. 503 */ 504 if (timo) { 505 if (td->td_flags & TDF_TIMEOUT) { 506 td->td_flags &= ~TDF_TIMEOUT; 507 error = EWOULDBLOCK; 508 } else { 509 callout_stop(&thandle); 510 } 511 } 512 513 /* 514 * Since td_threadq is used both for our run queue AND for the 515 * tsleep hash queue, we can't still be on it at this point because 516 * we've gotten cpu back. 517 */ 518 KASSERT((td->td_flags & TDF_TSLEEPQ) == 0, ("tsleep: impossible thread flags %08x", td->td_flags)); 519 td->td_wchan = NULL; 520 td->td_wmesg = NULL; 521 td->td_wdomain = 0; 522 523 /* 524 * Figure out the correct error return. If interrupted by a 525 * signal we want to return EINTR or ERESTART. 526 * 527 * If P_MAILBOX is set no automatic system call restart occurs 528 * and we return EINTR. P_MAILBOX is meant to be used as an 529 * interlock, the user must poll it prior to any system call 530 * that it wishes to interlock a mailbox signal against since 531 * the flag is cleared on *any* system call that sleeps. 532 */ 533 resume: 534 if (p) { 535 if (catch && error == 0) { 536 if ((p->p_flag & P_MAILBOX) && sig == 0) { 537 error = EINTR; 538 } else if (sig != 0 || (sig = CURSIG(lp))) { 539 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig)) 540 error = EINTR; 541 else 542 error = ERESTART; 543 } 544 } 545 lp->lwp_flag &= ~(LWP_BREAKTSLEEP | LWP_SINTR); 546 p->p_flag &= ~P_MAILBOX; 547 } 548 logtsleep1(tsleep_end); 549 crit_exit_quick(td); 550 return (error); 551 } 552 553 /* 554 * This is a dandy function that allows us to interlock tsleep/wakeup 555 * operations with unspecified upper level locks, such as lockmgr locks, 556 * simply by holding a critical section. The sequence is: 557 * 558 * (enter critical section) 559 * (acquire upper level lock) 560 * tsleep_interlock(blah) 561 * (release upper level lock) 562 * tsleep(blah, ...) 563 * (exit critical section) 564 * 565 * Basically this function sets our cpumask for the ident which informs 566 * other cpus that our cpu 'might' be waiting (or about to wait on) the 567 * hash index related to the ident. The critical section prevents another 568 * cpu's wakeup() from being processed on our cpu until we are actually 569 * able to enter the tsleep(). Thus, no race occurs between our attempt 570 * to release a resource and sleep, and another cpu's attempt to acquire 571 * a resource and call wakeup. 572 * 573 * There isn't much of a point to this function unless you call it while 574 * holding a critical section. 575 */ 576 static __inline void 577 _tsleep_interlock(globaldata_t gd, void *ident) 578 { 579 int id = LOOKUP(ident); 580 581 atomic_set_int(&slpque_cpumasks[id], gd->gd_cpumask); 582 } 583 584 void 585 tsleep_interlock(void *ident) 586 { 587 _tsleep_interlock(mycpu, ident); 588 } 589 590 /* 591 * Interlocked spinlock sleep. An exclusively held spinlock must 592 * be passed to msleep(). The function will atomically release the 593 * spinlock and tsleep on the ident, then reacquire the spinlock and 594 * return. 595 * 596 * This routine is fairly important along the critical path, so optimize it 597 * heavily. 598 */ 599 int 600 msleep(void *ident, struct spinlock *spin, int flags, 601 const char *wmesg, int timo) 602 { 603 globaldata_t gd = mycpu; 604 int error; 605 606 crit_enter_gd(gd); 607 _tsleep_interlock(gd, ident); 608 spin_unlock_wr_quick(gd, spin); 609 error = tsleep(ident, flags, wmesg, timo); 610 spin_lock_wr_quick(gd, spin); 611 crit_exit_gd(gd); 612 613 return (error); 614 } 615 616 /* 617 * Interlocked serializer sleep. An exclusively held serializer must 618 * be passed to serialize_sleep(). The function will atomically release 619 * the serializer and tsleep on the ident, then reacquire the serializer 620 * and return. 621 */ 622 int 623 serialize_sleep(void *ident, struct lwkt_serialize *slz, int flags, 624 const char *wmesg, int timo) 625 { 626 int ret; 627 628 ASSERT_SERIALIZED(slz); 629 630 crit_enter(); 631 tsleep_interlock(ident); 632 lwkt_serialize_exit(slz); 633 ret = tsleep(ident, flags, wmesg, timo); 634 lwkt_serialize_enter(slz); 635 crit_exit(); 636 637 return ret; 638 } 639 640 /* 641 * Directly block on the LWKT thread by descheduling it. This 642 * is much faster then tsleep(), but the only legal way to wake 643 * us up is to directly schedule the thread. 644 * 645 * Setting TDF_SINTR will cause new signals to directly schedule us. 646 * 647 * This routine is typically called while in a critical section. 648 */ 649 int 650 lwkt_sleep(const char *wmesg, int flags) 651 { 652 thread_t td = curthread; 653 int sig; 654 655 if ((flags & PCATCH) == 0 || td->td_lwp == NULL) { 656 td->td_flags |= TDF_BLOCKED; 657 td->td_wmesg = wmesg; 658 lwkt_deschedule_self(td); 659 lwkt_switch(); 660 td->td_wmesg = NULL; 661 td->td_flags &= ~TDF_BLOCKED; 662 return(0); 663 } 664 if ((sig = CURSIG(td->td_lwp)) != 0) { 665 if (SIGISMEMBER(td->td_proc->p_sigacts->ps_sigintr, sig)) 666 return(EINTR); 667 else 668 return(ERESTART); 669 670 } 671 td->td_flags |= TDF_BLOCKED | TDF_SINTR; 672 td->td_wmesg = wmesg; 673 lwkt_deschedule_self(td); 674 lwkt_switch(); 675 td->td_flags &= ~(TDF_BLOCKED | TDF_SINTR); 676 td->td_wmesg = NULL; 677 return(0); 678 } 679 680 /* 681 * Implement the timeout for tsleep. 682 * 683 * We set LWP_BREAKTSLEEP to indicate that an event has occured, but 684 * we only call setrunnable if the process is not stopped. 685 * 686 * This type of callout timeout is scheduled on the same cpu the process 687 * is sleeping on. Also, at the moment, the MP lock is held. 688 */ 689 static void 690 endtsleep(void *arg) 691 { 692 thread_t td = arg; 693 struct lwp *lp; 694 695 ASSERT_MP_LOCK_HELD(curthread); 696 crit_enter(); 697 698 /* 699 * cpu interlock. Thread flags are only manipulated on 700 * the cpu owning the thread. proc flags are only manipulated 701 * by the older of the MP lock. We have both. 702 */ 703 if (td->td_flags & TDF_TSLEEPQ) { 704 td->td_flags |= TDF_TIMEOUT; 705 706 if ((lp = td->td_lwp) != NULL) { 707 lp->lwp_flag |= LWP_BREAKTSLEEP; 708 if (lp->lwp_proc->p_stat != SSTOP) 709 setrunnable(lp); 710 } else { 711 unsleep_and_wakeup_thread(td); 712 } 713 } 714 crit_exit(); 715 } 716 717 /* 718 * Unsleep and wakeup a thread. This function runs without the MP lock 719 * which means that it can only manipulate thread state on the owning cpu, 720 * and cannot touch the process state at all. 721 */ 722 static 723 void 724 unsleep_and_wakeup_thread(struct thread *td) 725 { 726 globaldata_t gd = mycpu; 727 int id; 728 729 #ifdef SMP 730 if (td->td_gd != gd) { 731 lwkt_send_ipiq(td->td_gd, (ipifunc1_t)unsleep_and_wakeup_thread, td); 732 return; 733 } 734 #endif 735 crit_enter(); 736 if (td->td_flags & TDF_TSLEEPQ) { 737 td->td_flags &= ~TDF_TSLEEPQ; 738 id = LOOKUP(td->td_wchan); 739 TAILQ_REMOVE(&gd->gd_tsleep_hash[id], td, td_threadq); 740 if (TAILQ_FIRST(&gd->gd_tsleep_hash[id]) == NULL) 741 atomic_clear_int(&slpque_cpumasks[id], gd->gd_cpumask); 742 lwkt_schedule(td); 743 } 744 crit_exit(); 745 } 746 747 /* 748 * Make all processes sleeping on the specified identifier runnable. 749 * count may be zero or one only. 750 * 751 * The domain encodes the sleep/wakeup domain AND the first cpu to check 752 * (which is always the current cpu). As we iterate across cpus 753 * 754 * This call may run without the MP lock held. We can only manipulate thread 755 * state on the cpu owning the thread. We CANNOT manipulate process state 756 * at all. 757 */ 758 static void 759 _wakeup(void *ident, int domain) 760 { 761 struct tslpque *qp; 762 struct thread *td; 763 struct thread *ntd; 764 globaldata_t gd; 765 #ifdef SMP 766 cpumask_t mask; 767 #endif 768 int id; 769 770 crit_enter(); 771 logtsleep2(wakeup_beg, ident); 772 gd = mycpu; 773 id = LOOKUP(ident); 774 qp = &gd->gd_tsleep_hash[id]; 775 restart: 776 for (td = TAILQ_FIRST(qp); td != NULL; td = ntd) { 777 ntd = TAILQ_NEXT(td, td_threadq); 778 if (td->td_wchan == ident && 779 td->td_wdomain == (domain & PDOMAIN_MASK) 780 ) { 781 KKASSERT(td->td_flags & TDF_TSLEEPQ); 782 td->td_flags &= ~TDF_TSLEEPQ; 783 TAILQ_REMOVE(qp, td, td_threadq); 784 if (TAILQ_FIRST(qp) == NULL) { 785 atomic_clear_int(&slpque_cpumasks[id], 786 gd->gd_cpumask); 787 } 788 lwkt_schedule(td); 789 if (domain & PWAKEUP_ONE) 790 goto done; 791 goto restart; 792 } 793 } 794 795 #ifdef SMP 796 /* 797 * We finished checking the current cpu but there still may be 798 * more work to do. Either wakeup_one was requested and no matching 799 * thread was found, or a normal wakeup was requested and we have 800 * to continue checking cpus. 801 * 802 * It should be noted that this scheme is actually less expensive then 803 * the old scheme when waking up multiple threads, since we send 804 * only one IPI message per target candidate which may then schedule 805 * multiple threads. Before we could have wound up sending an IPI 806 * message for each thread on the target cpu (!= current cpu) that 807 * needed to be woken up. 808 * 809 * NOTE: Wakeups occuring on remote cpus are asynchronous. This 810 * should be ok since we are passing idents in the IPI rather then 811 * thread pointers. 812 */ 813 if ((domain & PWAKEUP_MYCPU) == 0 && 814 (mask = slpque_cpumasks[id] & gd->gd_other_cpus) != 0) { 815 lwkt_send_ipiq2_mask(mask, _wakeup, ident, 816 domain | PWAKEUP_MYCPU); 817 } 818 #endif 819 done: 820 logtsleep1(wakeup_end); 821 crit_exit(); 822 } 823 824 /* 825 * Wakeup all threads tsleep()ing on the specified ident, on all cpus 826 */ 827 void 828 wakeup(void *ident) 829 { 830 _wakeup(ident, PWAKEUP_ENCODE(0, mycpu->gd_cpuid)); 831 } 832 833 /* 834 * Wakeup one thread tsleep()ing on the specified ident, on any cpu. 835 */ 836 void 837 wakeup_one(void *ident) 838 { 839 /* XXX potentially round-robin the first responding cpu */ 840 _wakeup(ident, PWAKEUP_ENCODE(0, mycpu->gd_cpuid) | PWAKEUP_ONE); 841 } 842 843 /* 844 * Wakeup threads tsleep()ing on the specified ident on the current cpu 845 * only. 846 */ 847 void 848 wakeup_mycpu(void *ident) 849 { 850 _wakeup(ident, PWAKEUP_MYCPU); 851 } 852 853 /* 854 * Wakeup one thread tsleep()ing on the specified ident on the current cpu 855 * only. 856 */ 857 void 858 wakeup_mycpu_one(void *ident) 859 { 860 /* XXX potentially round-robin the first responding cpu */ 861 _wakeup(ident, PWAKEUP_MYCPU|PWAKEUP_ONE); 862 } 863 864 /* 865 * Wakeup all thread tsleep()ing on the specified ident on the specified cpu 866 * only. 867 */ 868 void 869 wakeup_oncpu(globaldata_t gd, void *ident) 870 { 871 #ifdef SMP 872 if (gd == mycpu) { 873 _wakeup(ident, PWAKEUP_MYCPU); 874 } else { 875 lwkt_send_ipiq2(gd, _wakeup, ident, PWAKEUP_MYCPU); 876 } 877 #else 878 _wakeup(ident, PWAKEUP_MYCPU); 879 #endif 880 } 881 882 /* 883 * Wakeup one thread tsleep()ing on the specified ident on the specified cpu 884 * only. 885 */ 886 void 887 wakeup_oncpu_one(globaldata_t gd, void *ident) 888 { 889 #ifdef SMP 890 if (gd == mycpu) { 891 _wakeup(ident, PWAKEUP_MYCPU | PWAKEUP_ONE); 892 } else { 893 lwkt_send_ipiq2(gd, _wakeup, ident, PWAKEUP_MYCPU | PWAKEUP_ONE); 894 } 895 #else 896 _wakeup(ident, PWAKEUP_MYCPU | PWAKEUP_ONE); 897 #endif 898 } 899 900 /* 901 * Wakeup all threads waiting on the specified ident that slept using 902 * the specified domain, on all cpus. 903 */ 904 void 905 wakeup_domain(void *ident, int domain) 906 { 907 _wakeup(ident, PWAKEUP_ENCODE(domain, mycpu->gd_cpuid)); 908 } 909 910 /* 911 * Wakeup one thread waiting on the specified ident that slept using 912 * the specified domain, on any cpu. 913 */ 914 void 915 wakeup_domain_one(void *ident, int domain) 916 { 917 /* XXX potentially round-robin the first responding cpu */ 918 _wakeup(ident, PWAKEUP_ENCODE(domain, mycpu->gd_cpuid) | PWAKEUP_ONE); 919 } 920 921 /* 922 * setrunnable() 923 * 924 * Make a process runnable. The MP lock must be held on call. This only 925 * has an effect if we are in SSLEEP. We only break out of the 926 * tsleep if LWP_BREAKTSLEEP is set, otherwise we just fix-up the state. 927 * 928 * NOTE: With the MP lock held we can only safely manipulate the process 929 * structure. We cannot safely manipulate the thread structure. 930 */ 931 void 932 setrunnable(struct lwp *lp) 933 { 934 crit_enter(); 935 ASSERT_MP_LOCK_HELD(curthread); 936 if (lp->lwp_stat == LSSTOP) 937 lp->lwp_stat = LSSLEEP; 938 if (lp->lwp_stat == LSSLEEP && (lp->lwp_flag & LWP_BREAKTSLEEP)) 939 unsleep_and_wakeup_thread(lp->lwp_thread); 940 crit_exit(); 941 } 942 943 /* 944 * The process is stopped due to some condition, usually because p_stat is 945 * set to SSTOP, but also possibly due to being traced. 946 * 947 * NOTE! If the caller sets SSTOP, the caller must also clear P_WAITED 948 * because the parent may check the child's status before the child actually 949 * gets to this routine. 950 * 951 * This routine is called with the current lwp only, typically just 952 * before returning to userland. 953 * 954 * Setting LWP_BREAKTSLEEP before entering the tsleep will cause a passive 955 * SIGCONT to break out of the tsleep. 956 */ 957 void 958 tstop(void) 959 { 960 struct lwp *lp = curthread->td_lwp; 961 struct proc *p = lp->lwp_proc; 962 963 lp->lwp_flag |= LWP_BREAKTSLEEP; 964 lp->lwp_stat = LSSTOP; 965 crit_enter(); 966 /* 967 * If LWP_WSTOP is set, we were sleeping 968 * while our process was stopped. At this point 969 * we were already counted as stopped. 970 */ 971 if ((lp->lwp_flag & LWP_WSTOP) == 0) { 972 /* 973 * If we're the last thread to stop, signal 974 * our parent. 975 */ 976 p->p_nstopped++; 977 lp->lwp_flag |= LWP_WSTOP; 978 if (p->p_nstopped == p->p_nthreads) { 979 p->p_flag &= ~P_WAITED; 980 wakeup(p->p_pptr); 981 if ((p->p_pptr->p_sigacts->ps_flag & PS_NOCLDSTOP) == 0) 982 ksignal(p->p_pptr, SIGCHLD); 983 } 984 } 985 tsleep(lp->lwp_proc, 0, "stop", 0); 986 p->p_nstopped--; 987 lp->lwp_flag &= ~LWP_WSTOP; 988 crit_exit(); 989 } 990 991 /* 992 * Yield / synchronous reschedule. This is a bit tricky because the trap 993 * code might have set a lazy release on the switch function. Setting 994 * P_PASSIVE_ACQ will ensure that the lazy release executes when we call 995 * switch, and that we are given a greater chance of affinity with our 996 * current cpu. 997 * 998 * We call lwkt_setpri_self() to rotate our thread to the end of the lwkt 999 * run queue. lwkt_switch() will also execute any assigned passive release 1000 * (which usually calls release_curproc()), allowing a same/higher priority 1001 * process to be designated as the current process. 1002 * 1003 * While it is possible for a lower priority process to be designated, 1004 * it's call to lwkt_maybe_switch() in acquire_curproc() will likely 1005 * round-robin back to us and we will be able to re-acquire the current 1006 * process designation. 1007 */ 1008 void 1009 uio_yield(void) 1010 { 1011 struct thread *td = curthread; 1012 struct proc *p = td->td_proc; 1013 1014 lwkt_setpri_self(td->td_pri & TDPRI_MASK); 1015 if (p) { 1016 p->p_flag |= P_PASSIVE_ACQ; 1017 lwkt_switch(); 1018 p->p_flag &= ~P_PASSIVE_ACQ; 1019 } else { 1020 lwkt_switch(); 1021 } 1022 } 1023 1024 /* 1025 * Compute a tenex style load average of a quantity on 1026 * 1, 5 and 15 minute intervals. 1027 */ 1028 static int loadav_count_runnable(struct lwp *p, void *data); 1029 1030 static void 1031 loadav(void *arg) 1032 { 1033 struct loadavg *avg; 1034 int i, nrun; 1035 1036 nrun = 0; 1037 alllwp_scan(loadav_count_runnable, &nrun); 1038 avg = &averunnable; 1039 for (i = 0; i < 3; i++) { 1040 avg->ldavg[i] = (cexp[i] * avg->ldavg[i] + 1041 nrun * FSCALE * (FSCALE - cexp[i])) >> FSHIFT; 1042 } 1043 1044 /* 1045 * Schedule the next update to occur after 5 seconds, but add a 1046 * random variation to avoid synchronisation with processes that 1047 * run at regular intervals. 1048 */ 1049 callout_reset(&loadav_callout, hz * 4 + (int)(krandom() % (hz * 2 + 1)), 1050 loadav, NULL); 1051 } 1052 1053 static int 1054 loadav_count_runnable(struct lwp *lp, void *data) 1055 { 1056 int *nrunp = data; 1057 thread_t td; 1058 1059 switch (lp->lwp_stat) { 1060 case LSRUN: 1061 if ((td = lp->lwp_thread) == NULL) 1062 break; 1063 if (td->td_flags & TDF_BLOCKED) 1064 break; 1065 ++*nrunp; 1066 break; 1067 default: 1068 break; 1069 } 1070 return(0); 1071 } 1072 1073 /* ARGSUSED */ 1074 static void 1075 sched_setup(void *dummy) 1076 { 1077 callout_init(&loadav_callout); 1078 callout_init(&schedcpu_callout); 1079 1080 /* Kick off timeout driven events by calling first time. */ 1081 schedcpu(NULL); 1082 loadav(NULL); 1083 } 1084 1085