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 1.57 2005/12/10 18:27:24 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/resourcevar.h> 51 #include <sys/vmmeter.h> 52 #include <sys/sysctl.h> 53 #include <sys/thread2.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 <machine/cpu.h> 63 #include <machine/ipl.h> 64 #include <machine/smp.h> 65 66 TAILQ_HEAD(tslpque, thread); 67 68 static void sched_setup (void *dummy); 69 SYSINIT(sched_setup, SI_SUB_KICK_SCHEDULER, SI_ORDER_FIRST, sched_setup, NULL) 70 71 int hogticks; 72 int lbolt; 73 int lbolt_syncer; 74 int sched_quantum; /* Roundrobin scheduling quantum in ticks. */ 75 int ncpus; 76 int ncpus2, ncpus2_shift, ncpus2_mask; 77 int safepri; 78 79 static struct callout loadav_callout; 80 static struct callout schedcpu_callout; 81 MALLOC_DEFINE(M_TSLEEP, "tslpque", "tsleep queues"); 82 83 #if !defined(KTR_TSLEEP) 84 #define KTR_TSLEEP KTR_ALL 85 #endif 86 KTR_INFO_MASTER(tsleep); 87 KTR_INFO(KTR_TSLEEP, tsleep, tsleep_beg, 0, "tsleep enter", 0); 88 KTR_INFO(KTR_TSLEEP, tsleep, tsleep_end, 0, "tsleep exit", 0); 89 KTR_INFO(KTR_TSLEEP, tsleep, wakeup_beg, 0, "wakeup enter", 0); 90 KTR_INFO(KTR_TSLEEP, tsleep, wakeup_end, 0, "wakeup exit", 0); 91 #define logtsleep(name) KTR_LOG(tsleep_ ## name) 92 93 struct loadavg averunnable = 94 { {0, 0, 0}, FSCALE }; /* load average, of runnable procs */ 95 /* 96 * Constants for averages over 1, 5, and 15 minutes 97 * when sampling at 5 second intervals. 98 */ 99 static fixpt_t cexp[3] = { 100 0.9200444146293232 * FSCALE, /* exp(-1/12) */ 101 0.9834714538216174 * FSCALE, /* exp(-1/60) */ 102 0.9944598480048967 * FSCALE, /* exp(-1/180) */ 103 }; 104 105 static void endtsleep (void *); 106 static void unsleep_and_wakeup_thread(struct thread *td); 107 static void loadav (void *arg); 108 static void schedcpu (void *arg); 109 110 /* 111 * Adjust the scheduler quantum. The quantum is specified in microseconds. 112 * Note that 'tick' is in microseconds per tick. 113 */ 114 static int 115 sysctl_kern_quantum(SYSCTL_HANDLER_ARGS) 116 { 117 int error, new_val; 118 119 new_val = sched_quantum * tick; 120 error = sysctl_handle_int(oidp, &new_val, 0, req); 121 if (error != 0 || req->newptr == NULL) 122 return (error); 123 if (new_val < tick) 124 return (EINVAL); 125 sched_quantum = new_val / tick; 126 hogticks = 2 * sched_quantum; 127 return (0); 128 } 129 130 SYSCTL_PROC(_kern, OID_AUTO, quantum, CTLTYPE_INT|CTLFLAG_RW, 131 0, sizeof sched_quantum, sysctl_kern_quantum, "I", ""); 132 133 /* 134 * If `ccpu' is not equal to `exp(-1/20)' and you still want to use the 135 * faster/more-accurate formula, you'll have to estimate CCPU_SHIFT below 136 * and possibly adjust FSHIFT in "param.h" so that (FSHIFT >= CCPU_SHIFT). 137 * 138 * To estimate CCPU_SHIFT for exp(-1/20), the following formula was used: 139 * 1 - exp(-1/20) ~= 0.0487 ~= 0.0488 == 1 (fixed pt, *11* bits). 140 * 141 * If you don't want to bother with the faster/more-accurate formula, you 142 * can set CCPU_SHIFT to (FSHIFT + 1) which will use a slower/less-accurate 143 * (more general) method of calculating the %age of CPU used by a process. 144 * 145 * decay 95% of `p_pctcpu' in 60 seconds; see CCPU_SHIFT before changing 146 */ 147 #define CCPU_SHIFT 11 148 149 static fixpt_t ccpu = 0.95122942450071400909 * FSCALE; /* exp(-1/20) */ 150 SYSCTL_INT(_kern, OID_AUTO, ccpu, CTLFLAG_RD, &ccpu, 0, ""); 151 152 /* 153 * kernel uses `FSCALE', userland (SHOULD) use kern.fscale 154 */ 155 static int fscale __unused = FSCALE; 156 SYSCTL_INT(_kern, OID_AUTO, fscale, CTLFLAG_RD, 0, FSCALE, ""); 157 158 /* 159 * Recompute process priorities, once a second. 160 * 161 * Since the userland schedulers are typically event oriented, if the 162 * estcpu calculation at wakeup() time is not sufficient to make a 163 * process runnable relative to other processes in the system we have 164 * a 1-second recalc to help out. 165 * 166 * This code also allows us to store sysclock_t data in the process structure 167 * without fear of an overrun, since sysclock_t are guarenteed to hold 168 * several seconds worth of count. 169 */ 170 /* ARGSUSED */ 171 static void 172 schedcpu(void *arg) 173 { 174 struct rlimit *rlim; 175 struct proc *p; 176 u_int64_t ttime; 177 178 /* 179 * General process statistics once a second 180 */ 181 FOREACH_PROC_IN_SYSTEM(p) { 182 crit_enter(); 183 p->p_swtime++; 184 if (p->p_stat == SSLEEP) 185 p->p_slptime++; 186 187 /* 188 * Only recalculate processes that are active or have slept 189 * less then 2 seconds. The schedulers understand this. 190 */ 191 if (p->p_slptime <= 1) { 192 p->p_usched->recalculate(&p->p_lwp); 193 } else { 194 p->p_pctcpu = (p->p_pctcpu * ccpu) >> FSHIFT; 195 } 196 crit_exit(); 197 } 198 199 /* 200 * Resource checks. XXX break out since psignal/killproc can block, 201 * limiting us to one process killed per second. There is probably 202 * a better way. 203 */ 204 FOREACH_PROC_IN_SYSTEM(p) { 205 crit_enter(); 206 if (p->p_stat == SIDL || 207 (p->p_flag & P_ZOMBIE) || 208 p->p_limit == NULL || 209 p->p_thread == NULL 210 ) { 211 crit_exit(); 212 continue; 213 } 214 ttime = p->p_thread->td_sticks + p->p_thread->td_uticks; 215 if (p->p_limit->p_cpulimit != RLIM_INFINITY && 216 ttime > p->p_limit->p_cpulimit 217 ) { 218 rlim = &p->p_rlimit[RLIMIT_CPU]; 219 if (ttime / (rlim_t)1000000 >= rlim->rlim_max) { 220 killproc(p, "exceeded maximum CPU limit"); 221 } else { 222 psignal(p, SIGXCPU); 223 if (rlim->rlim_cur < rlim->rlim_max) { 224 /* XXX: we should make a private copy */ 225 rlim->rlim_cur += 5; 226 } 227 } 228 crit_exit(); 229 break; 230 } 231 crit_exit(); 232 } 233 234 wakeup((caddr_t)&lbolt); 235 wakeup((caddr_t)&lbolt_syncer); 236 callout_reset(&schedcpu_callout, hz, schedcpu, NULL); 237 } 238 239 /* 240 * This is only used by ps. Generate a cpu percentage use over 241 * a period of one second. 242 */ 243 void 244 updatepcpu(struct lwp *lp, int cpticks, int ttlticks) 245 { 246 fixpt_t acc; 247 int remticks; 248 249 acc = (cpticks << FSHIFT) / ttlticks; 250 if (ttlticks >= ESTCPUFREQ) { 251 lp->lwp_pctcpu = acc; 252 } else { 253 remticks = ESTCPUFREQ - ttlticks; 254 lp->lwp_pctcpu = (acc * ttlticks + lp->lwp_pctcpu * remticks) / 255 ESTCPUFREQ; 256 } 257 } 258 259 /* 260 * We're only looking at 7 bits of the address; everything is 261 * aligned to 4, lots of things are aligned to greater powers 262 * of 2. Shift right by 8, i.e. drop the bottom 256 worth. 263 */ 264 #define TABLESIZE 128 265 #define LOOKUP(x) (((intptr_t)(x) >> 8) & (TABLESIZE - 1)) 266 267 static cpumask_t slpque_cpumasks[TABLESIZE]; 268 269 /* 270 * General scheduler initialization. We force a reschedule 25 times 271 * a second by default. Note that cpu0 is initialized in early boot and 272 * cannot make any high level calls. 273 * 274 * Each cpu has its own sleep queue. 275 */ 276 void 277 sleep_gdinit(globaldata_t gd) 278 { 279 static struct tslpque slpque_cpu0[TABLESIZE]; 280 int i; 281 282 if (gd->gd_cpuid == 0) { 283 sched_quantum = (hz + 24) / 25; 284 hogticks = 2 * sched_quantum; 285 286 gd->gd_tsleep_hash = slpque_cpu0; 287 } else { 288 gd->gd_tsleep_hash = malloc(sizeof(slpque_cpu0), 289 M_TSLEEP, M_WAITOK | M_ZERO); 290 } 291 for (i = 0; i < TABLESIZE; ++i) 292 TAILQ_INIT(&gd->gd_tsleep_hash[i]); 293 } 294 295 /* 296 * General sleep call. Suspends the current process until a wakeup is 297 * performed on the specified identifier. The process will then be made 298 * runnable with the specified priority. Sleeps at most timo/hz seconds 299 * (0 means no timeout). If flags includes PCATCH flag, signals are checked 300 * before and after sleeping, else signals are not checked. Returns 0 if 301 * awakened, EWOULDBLOCK if the timeout expires. If PCATCH is set and a 302 * signal needs to be delivered, ERESTART is returned if the current system 303 * call should be restarted if possible, and EINTR is returned if the system 304 * call should be interrupted by the signal (return EINTR). 305 * 306 * Note that if we are a process, we release_curproc() before messing with 307 * the LWKT scheduler. 308 * 309 * During autoconfiguration or after a panic, a sleep will simply 310 * lower the priority briefly to allow interrupts, then return. 311 */ 312 int 313 tsleep(void *ident, int flags, const char *wmesg, int timo) 314 { 315 struct thread *td = curthread; 316 struct proc *p = td->td_proc; /* may be NULL */ 317 globaldata_t gd; 318 int sig; 319 int catch; 320 int id; 321 int error; 322 int oldpri; 323 struct callout thandle; 324 325 /* 326 * NOTE: removed KTRPOINT, it could cause races due to blocking 327 * even in stable. Just scrap it for now. 328 */ 329 if (cold || panicstr) { 330 /* 331 * After a panic, or during autoconfiguration, 332 * just give interrupts a chance, then just return; 333 * don't run any other procs or panic below, 334 * in case this is the idle process and already asleep. 335 */ 336 splz(); 337 oldpri = td->td_pri & TDPRI_MASK; 338 lwkt_setpri_self(safepri); 339 lwkt_switch(); 340 lwkt_setpri_self(oldpri); 341 return (0); 342 } 343 logtsleep(tsleep_beg); 344 gd = td->td_gd; 345 KKASSERT(td != &gd->gd_idlethread); /* you must be kidding! */ 346 347 /* 348 * NOTE: all of this occurs on the current cpu, including any 349 * callout-based wakeups, so a critical section is a sufficient 350 * interlock. 351 * 352 * The entire sequence through to where we actually sleep must 353 * run without breaking the critical section. 354 */ 355 id = LOOKUP(ident); 356 catch = flags & PCATCH; 357 error = 0; 358 sig = 0; 359 360 crit_enter_quick(td); 361 362 KASSERT(ident != NULL, ("tsleep: no ident")); 363 KASSERT(p == NULL || p->p_stat == SRUN, ("tsleep %p %s %d", 364 ident, wmesg, p->p_stat)); 365 366 /* 367 * Setup for the current process (if this is a process). 368 */ 369 if (p) { 370 if (catch) { 371 /* 372 * Early termination if PCATCH was set and a 373 * signal is pending, interlocked with the 374 * critical section. 375 * 376 * Early termination only occurs when tsleep() is 377 * entered while in a normal SRUN state. 378 */ 379 if ((sig = CURSIG(p)) != 0) 380 goto resume; 381 382 /* 383 * Causes psignal to wake us up when. 384 */ 385 p->p_flag |= P_SINTR; 386 } 387 388 /* 389 * Make sure the current process has been untangled from 390 * the userland scheduler and initialize slptime to start 391 * counting. 392 */ 393 if (flags & PNORESCHED) 394 td->td_flags |= TDF_NORESCHED; 395 p->p_usched->release_curproc(&p->p_lwp); 396 p->p_slptime = 0; 397 } 398 399 /* 400 * Move our thread to the correct queue and setup our wchan, etc. 401 */ 402 lwkt_deschedule_self(td); 403 td->td_flags |= TDF_TSLEEPQ; 404 TAILQ_INSERT_TAIL(&gd->gd_tsleep_hash[id], td, td_threadq); 405 atomic_set_int(&slpque_cpumasks[id], gd->gd_cpumask); 406 407 td->td_wchan = ident; 408 td->td_wmesg = wmesg; 409 td->td_wdomain = flags & PDOMAIN_MASK; 410 411 /* 412 * Setup the timeout, if any 413 */ 414 if (timo) { 415 callout_init(&thandle); 416 callout_reset(&thandle, timo, endtsleep, td); 417 } 418 419 /* 420 * Beddy bye bye. 421 */ 422 if (p) { 423 /* 424 * Ok, we are sleeping. Remove us from the userland runq 425 * and place us in the SSLEEP state. 426 */ 427 if (p->p_flag & P_ONRUNQ) 428 p->p_usched->remrunqueue(&p->p_lwp); 429 p->p_stat = SSLEEP; 430 p->p_stats->p_ru.ru_nvcsw++; 431 lwkt_switch(); 432 p->p_stat = SRUN; 433 } else { 434 lwkt_switch(); 435 } 436 437 /* 438 * Make sure we haven't switched cpus while we were asleep. It's 439 * not supposed to happen. Cleanup our temporary flags. 440 */ 441 KKASSERT(gd == td->td_gd); 442 td->td_flags &= ~TDF_NORESCHED; 443 444 /* 445 * Cleanup the timeout. 446 */ 447 if (timo) { 448 if (td->td_flags & TDF_TIMEOUT) { 449 td->td_flags &= ~TDF_TIMEOUT; 450 if (sig == 0) 451 error = EWOULDBLOCK; 452 } else { 453 callout_stop(&thandle); 454 } 455 } 456 457 /* 458 * Since td_threadq is used both for our run queue AND for the 459 * tsleep hash queue, we can't still be on it at this point because 460 * we've gotten cpu back. 461 */ 462 KASSERT((td->td_flags & TDF_TSLEEPQ) == 0, ("tsleep: impossible thread flags %08x", td->td_flags)); 463 td->td_wchan = NULL; 464 td->td_wmesg = NULL; 465 td->td_wdomain = 0; 466 467 /* 468 * Figure out the correct error return 469 */ 470 resume: 471 if (p) { 472 p->p_flag &= ~(P_BREAKTSLEEP | P_SINTR); 473 if (catch && error == 0 && (sig != 0 || (sig = CURSIG(p)))) { 474 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig)) 475 error = EINTR; 476 else 477 error = ERESTART; 478 } 479 } 480 logtsleep(tsleep_end); 481 crit_exit_quick(td); 482 return (error); 483 } 484 485 /* 486 * This is a dandy function that allows us to interlock tsleep/wakeup 487 * operations with unspecified upper level locks, such as lockmgr locks, 488 * simply by holding a critical section. The sequence is: 489 * 490 * (enter critical section) 491 * (acquire upper level lock) 492 * tsleep_interlock(blah) 493 * (release upper level lock) 494 * tsleep(blah, ...) 495 * (exit critical section) 496 * 497 * Basically this function sets our cpumask for the ident which informs 498 * other cpus that our cpu 'might' be waiting (or about to wait on) the 499 * hash index related to the ident. The critical section prevents another 500 * cpu's wakeup() from being processed on our cpu until we are actually 501 * able to enter the tsleep(). Thus, no race occurs between our attempt 502 * to release a resource and sleep, and another cpu's attempt to acquire 503 * a resource and call wakeup. 504 * 505 * There isn't much of a point to this function unless you call it while 506 * holding a critical section. 507 */ 508 void 509 tsleep_interlock(void *ident) 510 { 511 int id = LOOKUP(ident); 512 513 atomic_set_int(&slpque_cpumasks[id], mycpu->gd_cpumask); 514 } 515 516 /* 517 * Implement the timeout for tsleep. 518 * 519 * We set P_BREAKTSLEEP to indicate that an event has occured, but 520 * we only call setrunnable if the process is not stopped. 521 * 522 * This type of callout timeout is scheduled on the same cpu the process 523 * is sleeping on. Also, at the moment, the MP lock is held. 524 */ 525 static void 526 endtsleep(void *arg) 527 { 528 thread_t td = arg; 529 struct proc *p; 530 531 ASSERT_MP_LOCK_HELD(curthread); 532 crit_enter(); 533 534 /* 535 * cpu interlock. Thread flags are only manipulated on 536 * the cpu owning the thread. proc flags are only manipulated 537 * by the older of the MP lock. We have both. 538 */ 539 if (td->td_flags & TDF_TSLEEPQ) { 540 td->td_flags |= TDF_TIMEOUT; 541 542 if ((p = td->td_proc) != NULL) { 543 p->p_flag |= P_BREAKTSLEEP; 544 if ((p->p_flag & P_STOPPED) == 0) 545 setrunnable(p); 546 } else { 547 unsleep_and_wakeup_thread(td); 548 } 549 } 550 crit_exit(); 551 } 552 553 /* 554 * Unsleep and wakeup a thread. This function runs without the MP lock 555 * which means that it can only manipulate thread state on the owning cpu, 556 * and cannot touch the process state at all. 557 */ 558 static 559 void 560 unsleep_and_wakeup_thread(struct thread *td) 561 { 562 globaldata_t gd = mycpu; 563 int id; 564 565 #ifdef SMP 566 if (td->td_gd != gd) { 567 lwkt_send_ipiq(td->td_gd, (ipifunc1_t)unsleep_and_wakeup_thread, td); 568 return; 569 } 570 #endif 571 crit_enter(); 572 if (td->td_flags & TDF_TSLEEPQ) { 573 td->td_flags &= ~TDF_TSLEEPQ; 574 id = LOOKUP(td->td_wchan); 575 TAILQ_REMOVE(&gd->gd_tsleep_hash[id], td, td_threadq); 576 if (TAILQ_FIRST(&gd->gd_tsleep_hash[id]) == NULL) 577 atomic_clear_int(&slpque_cpumasks[id], gd->gd_cpumask); 578 lwkt_schedule(td); 579 } 580 crit_exit(); 581 } 582 583 /* 584 * Make all processes sleeping on the specified identifier runnable. 585 * count may be zero or one only. 586 * 587 * The domain encodes the sleep/wakeup domain AND the first cpu to check 588 * (which is always the current cpu). As we iterate across cpus 589 * 590 * This call may run without the MP lock held. We can only manipulate thread 591 * state on the cpu owning the thread. We CANNOT manipulate process state 592 * at all. 593 */ 594 static void 595 _wakeup(void *ident, int domain) 596 { 597 struct tslpque *qp; 598 struct thread *td; 599 struct thread *ntd; 600 globaldata_t gd; 601 #ifdef SMP 602 cpumask_t mask; 603 cpumask_t tmask; 604 int startcpu; 605 int nextcpu; 606 #endif 607 int id; 608 609 crit_enter(); 610 logtsleep(wakeup_beg); 611 gd = mycpu; 612 id = LOOKUP(ident); 613 qp = &gd->gd_tsleep_hash[id]; 614 restart: 615 for (td = TAILQ_FIRST(qp); td != NULL; td = ntd) { 616 ntd = TAILQ_NEXT(td, td_threadq); 617 if (td->td_wchan == ident && 618 td->td_wdomain == (domain & PDOMAIN_MASK) 619 ) { 620 KKASSERT(td->td_flags & TDF_TSLEEPQ); 621 td->td_flags &= ~TDF_TSLEEPQ; 622 TAILQ_REMOVE(qp, td, td_threadq); 623 if (TAILQ_FIRST(qp) == NULL) { 624 atomic_clear_int(&slpque_cpumasks[id], 625 gd->gd_cpumask); 626 } 627 lwkt_schedule(td); 628 if (domain & PWAKEUP_ONE) 629 goto done; 630 goto restart; 631 } 632 } 633 634 #ifdef SMP 635 /* 636 * We finished checking the current cpu but there still may be 637 * more work to do. Either wakeup_one was requested and no matching 638 * thread was found, or a normal wakeup was requested and we have 639 * to continue checking cpus. 640 * 641 * The cpu that started the wakeup sequence is encoded in the domain. 642 * We use this information to determine which cpus still need to be 643 * checked, locate a candidate cpu, and chain the wakeup 644 * asynchronously with an IPI message. 645 * 646 * It should be noted that this scheme is actually less expensive then 647 * the old scheme when waking up multiple threads, since we send 648 * only one IPI message per target candidate which may then schedule 649 * multiple threads. Before we could have wound up sending an IPI 650 * message for each thread on the target cpu (!= current cpu) that 651 * needed to be woken up. 652 * 653 * NOTE: Wakeups occuring on remote cpus are asynchronous. This 654 * should be ok since we are passing idents in the IPI rather then 655 * thread pointers. 656 */ 657 if ((mask = slpque_cpumasks[id]) != 0) { 658 /* 659 * Look for a cpu that might have work to do. Mask out cpus 660 * which have already been processed. 661 * 662 * 31xxxxxxxxxxxxxxxxxxxxxxxxxxxxx0 663 * ^ ^ ^ 664 * start currentcpu start 665 * case2 case1 666 * * * * 667 * 11111111111111110000000000000111 case1 668 * 00000000111111110000000000000000 case2 669 * 670 * case1: We started at start_case1 and processed through 671 * to the current cpu. We have to check any bits 672 * after the current cpu, then check bits before 673 * the starting cpu. 674 * 675 * case2: We have already checked all the bits from 676 * start_case2 to the end, and from 0 to the current 677 * cpu. We just have the bits from the current cpu 678 * to start_case2 left to check. 679 */ 680 startcpu = PWAKEUP_DECODE(domain); 681 if (gd->gd_cpuid >= startcpu) { 682 /* 683 * CASE1 684 */ 685 tmask = mask & ~((gd->gd_cpumask << 1) - 1); 686 if (mask & tmask) { 687 nextcpu = bsfl(mask & tmask); 688 lwkt_send_ipiq2(globaldata_find(nextcpu), 689 _wakeup, ident, domain); 690 } else { 691 tmask = (1 << startcpu) - 1; 692 if (mask & tmask) { 693 nextcpu = bsfl(mask & tmask); 694 lwkt_send_ipiq2( 695 globaldata_find(nextcpu), 696 _wakeup, ident, domain); 697 } 698 } 699 } else { 700 /* 701 * CASE2 702 */ 703 tmask = ~((gd->gd_cpumask << 1) - 1) & 704 ((1 << startcpu) - 1); 705 if (mask & tmask) { 706 nextcpu = bsfl(mask & tmask); 707 lwkt_send_ipiq2(globaldata_find(nextcpu), 708 _wakeup, ident, domain); 709 } 710 } 711 } 712 #endif 713 done: 714 logtsleep(wakeup_end); 715 crit_exit(); 716 } 717 718 void 719 wakeup(void *ident) 720 { 721 _wakeup(ident, PWAKEUP_ENCODE(0, mycpu->gd_cpuid)); 722 } 723 724 void 725 wakeup_one(void *ident) 726 { 727 /* XXX potentially round-robin the first responding cpu */ 728 _wakeup(ident, PWAKEUP_ENCODE(0, mycpu->gd_cpuid) | PWAKEUP_ONE); 729 } 730 731 void 732 wakeup_domain(void *ident, int domain) 733 { 734 _wakeup(ident, PWAKEUP_ENCODE(domain, mycpu->gd_cpuid)); 735 } 736 737 void 738 wakeup_domain_one(void *ident, int domain) 739 { 740 /* XXX potentially round-robin the first responding cpu */ 741 _wakeup(ident, PWAKEUP_ENCODE(domain, mycpu->gd_cpuid) | PWAKEUP_ONE); 742 } 743 744 /* 745 * setrunnable() 746 * 747 * Make a process runnable. The MP lock must be held on call. This only 748 * has an effect if we are in SSLEEP. We only break out of the 749 * tsleep if P_BREAKTSLEEP is set, otherwise we just fix-up the state. 750 * 751 * NOTE: With the MP lock held we can only safely manipulate the process 752 * structure. We cannot safely manipulate the thread structure. 753 */ 754 void 755 setrunnable(struct proc *p) 756 { 757 crit_enter(); 758 ASSERT_MP_LOCK_HELD(curthread); 759 p->p_flag &= ~P_STOPPED; 760 if (p->p_stat == SSLEEP && (p->p_flag & P_BREAKTSLEEP)) { 761 unsleep_and_wakeup_thread(p->p_thread); 762 } 763 crit_exit(); 764 } 765 766 /* 767 * The process is stopped due to some condition, usually because P_STOPPED 768 * is set but also possibly due to being traced. 769 * 770 * NOTE! If the caller sets P_STOPPED, the caller must also clear P_WAITED 771 * because the parent may check the child's status before the child actually 772 * gets to this routine. 773 * 774 * This routine is called with the current process only, typically just 775 * before returning to userland. 776 * 777 * Setting P_BREAKTSLEEP before entering the tsleep will cause a passive 778 * SIGCONT to break out of the tsleep. 779 */ 780 void 781 tstop(struct proc *p) 782 { 783 wakeup((caddr_t)p->p_pptr); 784 p->p_flag |= P_BREAKTSLEEP; 785 tsleep(p, 0, "stop", 0); 786 } 787 788 /* 789 * Yield / synchronous reschedule. This is a bit tricky because the trap 790 * code might have set a lazy release on the switch function. Setting 791 * P_PASSIVE_ACQ will ensure that the lazy release executes when we call 792 * switch, and that we are given a greater chance of affinity with our 793 * current cpu. 794 * 795 * We call lwkt_setpri_self() to rotate our thread to the end of the lwkt 796 * run queue. lwkt_switch() will also execute any assigned passive release 797 * (which usually calls release_curproc()), allowing a same/higher priority 798 * process to be designated as the current process. 799 * 800 * While it is possible for a lower priority process to be designated, 801 * it's call to lwkt_maybe_switch() in acquire_curproc() will likely 802 * round-robin back to us and we will be able to re-acquire the current 803 * process designation. 804 */ 805 void 806 uio_yield(void) 807 { 808 struct thread *td = curthread; 809 struct proc *p = td->td_proc; 810 811 lwkt_setpri_self(td->td_pri & TDPRI_MASK); 812 if (p) { 813 p->p_flag |= P_PASSIVE_ACQ; 814 lwkt_switch(); 815 p->p_flag &= ~P_PASSIVE_ACQ; 816 } else { 817 lwkt_switch(); 818 } 819 } 820 821 /* 822 * Compute a tenex style load average of a quantity on 823 * 1, 5 and 15 minute intervals. 824 */ 825 static void 826 loadav(void *arg) 827 { 828 int i, nrun; 829 struct loadavg *avg; 830 struct proc *p; 831 thread_t td; 832 833 avg = &averunnable; 834 nrun = 0; 835 FOREACH_PROC_IN_SYSTEM(p) { 836 switch (p->p_stat) { 837 case SRUN: 838 if ((td = p->p_thread) == NULL) 839 break; 840 if (td->td_flags & TDF_BLOCKED) 841 break; 842 /* fall through */ 843 case SIDL: 844 nrun++; 845 break; 846 default: 847 break; 848 } 849 } 850 for (i = 0; i < 3; i++) 851 avg->ldavg[i] = (cexp[i] * avg->ldavg[i] + 852 nrun * FSCALE * (FSCALE - cexp[i])) >> FSHIFT; 853 854 /* 855 * Schedule the next update to occur after 5 seconds, but add a 856 * random variation to avoid synchronisation with processes that 857 * run at regular intervals. 858 */ 859 callout_reset(&loadav_callout, hz * 4 + (int)(random() % (hz * 2 + 1)), 860 loadav, NULL); 861 } 862 863 /* ARGSUSED */ 864 static void 865 sched_setup(void *dummy) 866 { 867 callout_init(&loadav_callout); 868 callout_init(&schedcpu_callout); 869 870 /* Kick off timeout driven events by calling first time. */ 871 schedcpu(NULL); 872 loadav(NULL); 873 } 874 875