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 1.63 2006/05/29 03:57:20 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/lock.h> 54 #ifdef KTRACE 55 #include <sys/uio.h> 56 #include <sys/ktrace.h> 57 #endif 58 #include <sys/xwait.h> 59 #include <sys/ktr.h> 60 61 #include <sys/thread2.h> 62 #include <sys/spinlock2.h> 63 64 #include <machine/cpu.h> 65 #include <machine/ipl.h> 66 #include <machine/smp.h> 67 68 TAILQ_HEAD(tslpque, thread); 69 70 static void sched_setup (void *dummy); 71 SYSINIT(sched_setup, SI_SUB_KICK_SCHEDULER, SI_ORDER_FIRST, sched_setup, NULL) 72 73 int hogticks; 74 int lbolt; 75 int lbolt_syncer; 76 int sched_quantum; /* Roundrobin scheduling quantum in ticks. */ 77 int ncpus; 78 int ncpus2, ncpus2_shift, ncpus2_mask; 79 int safepri; 80 81 static struct callout loadav_callout; 82 static struct callout schedcpu_callout; 83 MALLOC_DEFINE(M_TSLEEP, "tslpque", "tsleep queues"); 84 85 #if !defined(KTR_TSLEEP) 86 #define KTR_TSLEEP KTR_ALL 87 #endif 88 KTR_INFO_MASTER(tsleep); 89 KTR_INFO(KTR_TSLEEP, tsleep, tsleep_beg, 0, "tsleep enter", 0); 90 KTR_INFO(KTR_TSLEEP, tsleep, tsleep_end, 0, "tsleep exit", 0); 91 KTR_INFO(KTR_TSLEEP, tsleep, wakeup_beg, 0, "wakeup enter", 0); 92 KTR_INFO(KTR_TSLEEP, tsleep, wakeup_end, 0, "wakeup exit", 0); 93 #define logtsleep(name) KTR_LOG(tsleep_ ## name) 94 95 struct loadavg averunnable = 96 { {0, 0, 0}, FSCALE }; /* load average, of runnable procs */ 97 /* 98 * Constants for averages over 1, 5, and 15 minutes 99 * when sampling at 5 second intervals. 100 */ 101 static fixpt_t cexp[3] = { 102 0.9200444146293232 * FSCALE, /* exp(-1/12) */ 103 0.9834714538216174 * FSCALE, /* exp(-1/60) */ 104 0.9944598480048967 * FSCALE, /* exp(-1/180) */ 105 }; 106 107 static void endtsleep (void *); 108 static void unsleep_and_wakeup_thread(struct thread *td); 109 static void loadav (void *arg); 110 static void schedcpu (void *arg); 111 112 /* 113 * Adjust the scheduler quantum. The quantum is specified in microseconds. 114 * Note that 'tick' is in microseconds per tick. 115 */ 116 static int 117 sysctl_kern_quantum(SYSCTL_HANDLER_ARGS) 118 { 119 int error, new_val; 120 121 new_val = sched_quantum * tick; 122 error = sysctl_handle_int(oidp, &new_val, 0, req); 123 if (error != 0 || req->newptr == NULL) 124 return (error); 125 if (new_val < tick) 126 return (EINVAL); 127 sched_quantum = new_val / tick; 128 hogticks = 2 * sched_quantum; 129 return (0); 130 } 131 132 SYSCTL_PROC(_kern, OID_AUTO, quantum, CTLTYPE_INT|CTLFLAG_RW, 133 0, sizeof sched_quantum, sysctl_kern_quantum, "I", ""); 134 135 /* 136 * If `ccpu' is not equal to `exp(-1/20)' and you still want to use the 137 * faster/more-accurate formula, you'll have to estimate CCPU_SHIFT below 138 * and possibly adjust FSHIFT in "param.h" so that (FSHIFT >= CCPU_SHIFT). 139 * 140 * To estimate CCPU_SHIFT for exp(-1/20), the following formula was used: 141 * 1 - exp(-1/20) ~= 0.0487 ~= 0.0488 == 1 (fixed pt, *11* bits). 142 * 143 * If you don't want to bother with the faster/more-accurate formula, you 144 * can set CCPU_SHIFT to (FSHIFT + 1) which will use a slower/less-accurate 145 * (more general) method of calculating the %age of CPU used by a process. 146 * 147 * decay 95% of `p_pctcpu' in 60 seconds; see CCPU_SHIFT before changing 148 */ 149 #define CCPU_SHIFT 11 150 151 static fixpt_t ccpu = 0.95122942450071400909 * FSCALE; /* exp(-1/20) */ 152 SYSCTL_INT(_kern, OID_AUTO, ccpu, CTLFLAG_RD, &ccpu, 0, ""); 153 154 /* 155 * kernel uses `FSCALE', userland (SHOULD) use kern.fscale 156 */ 157 static int fscale __unused = FSCALE; 158 SYSCTL_INT(_kern, OID_AUTO, fscale, CTLFLAG_RD, 0, FSCALE, ""); 159 160 /* 161 * Recompute process priorities, once a second. 162 * 163 * Since the userland schedulers are typically event oriented, if the 164 * estcpu calculation at wakeup() time is not sufficient to make a 165 * process runnable relative to other processes in the system we have 166 * a 1-second recalc to help out. 167 * 168 * This code also allows us to store sysclock_t data in the process structure 169 * without fear of an overrun, since sysclock_t are guarenteed to hold 170 * several seconds worth of count. 171 * 172 * WARNING! callouts can preempt normal threads. However, they will not 173 * preempt a thread holding a spinlock so we *can* safely use spinlocks. 174 */ 175 static int schedcpu_stats(struct proc *p, void *data __unused); 176 static int schedcpu_resource(struct proc *p, void *data __unused); 177 178 static void 179 schedcpu(void *arg) 180 { 181 allproc_scan(schedcpu_stats, NULL); 182 allproc_scan(schedcpu_resource, NULL); 183 wakeup((caddr_t)&lbolt); 184 wakeup((caddr_t)&lbolt_syncer); 185 callout_reset(&schedcpu_callout, hz, schedcpu, NULL); 186 } 187 188 /* 189 * General process statistics once a second 190 */ 191 static int 192 schedcpu_stats(struct proc *p, void *data __unused) 193 { 194 crit_enter(); 195 p->p_swtime++; 196 if (p->p_stat == SSLEEP) 197 p->p_slptime++; 198 199 /* 200 * Only recalculate processes that are active or have slept 201 * less then 2 seconds. The schedulers understand this. 202 */ 203 if (p->p_slptime <= 1) { 204 p->p_usched->recalculate(&p->p_lwp); 205 } else { 206 p->p_pctcpu = (p->p_pctcpu * ccpu) >> FSHIFT; 207 } 208 crit_exit(); 209 return(0); 210 } 211 212 /* 213 * Resource checks. XXX break out since psignal/killproc can block, 214 * limiting us to one process killed per second. There is probably 215 * a better way. 216 */ 217 static int 218 schedcpu_resource(struct proc *p, void *data __unused) 219 { 220 u_int64_t ttime; 221 222 crit_enter(); 223 if (p->p_stat == SIDL || 224 (p->p_flag & P_ZOMBIE) || 225 p->p_limit == NULL || 226 p->p_thread == NULL 227 ) { 228 crit_exit(); 229 return(0); 230 } 231 232 ttime = p->p_thread->td_sticks + p->p_thread->td_uticks; 233 234 switch(plimit_testcpulimit(p->p_limit, ttime)) { 235 case PLIMIT_TESTCPU_KILL: 236 killproc(p, "exceeded maximum CPU limit"); 237 break; 238 case PLIMIT_TESTCPU_XCPU: 239 if ((p->p_flag & P_XCPU) == 0) { 240 p->p_flag |= P_XCPU; 241 psignal(p, SIGXCPU); 242 } 243 break; 244 default: 245 break; 246 } 247 crit_exit(); 248 return(0); 249 } 250 251 /* 252 * This is only used by ps. Generate a cpu percentage use over 253 * a period of one second. 254 * 255 * MPSAFE 256 */ 257 void 258 updatepcpu(struct lwp *lp, int cpticks, int ttlticks) 259 { 260 fixpt_t acc; 261 int remticks; 262 263 acc = (cpticks << FSHIFT) / ttlticks; 264 if (ttlticks >= ESTCPUFREQ) { 265 lp->lwp_pctcpu = acc; 266 } else { 267 remticks = ESTCPUFREQ - ttlticks; 268 lp->lwp_pctcpu = (acc * ttlticks + lp->lwp_pctcpu * remticks) / 269 ESTCPUFREQ; 270 } 271 } 272 273 /* 274 * We're only looking at 7 bits of the address; everything is 275 * aligned to 4, lots of things are aligned to greater powers 276 * of 2. Shift right by 8, i.e. drop the bottom 256 worth. 277 */ 278 #define TABLESIZE 128 279 #define LOOKUP(x) (((intptr_t)(x) >> 8) & (TABLESIZE - 1)) 280 281 static cpumask_t slpque_cpumasks[TABLESIZE]; 282 283 /* 284 * General scheduler initialization. We force a reschedule 25 times 285 * a second by default. Note that cpu0 is initialized in early boot and 286 * cannot make any high level calls. 287 * 288 * Each cpu has its own sleep queue. 289 */ 290 void 291 sleep_gdinit(globaldata_t gd) 292 { 293 static struct tslpque slpque_cpu0[TABLESIZE]; 294 int i; 295 296 if (gd->gd_cpuid == 0) { 297 sched_quantum = (hz + 24) / 25; 298 hogticks = 2 * sched_quantum; 299 300 gd->gd_tsleep_hash = slpque_cpu0; 301 } else { 302 gd->gd_tsleep_hash = malloc(sizeof(slpque_cpu0), 303 M_TSLEEP, M_WAITOK | M_ZERO); 304 } 305 for (i = 0; i < TABLESIZE; ++i) 306 TAILQ_INIT(&gd->gd_tsleep_hash[i]); 307 } 308 309 /* 310 * General sleep call. Suspends the current process until a wakeup is 311 * performed on the specified identifier. The process will then be made 312 * runnable with the specified priority. Sleeps at most timo/hz seconds 313 * (0 means no timeout). If flags includes PCATCH flag, signals are checked 314 * before and after sleeping, else signals are not checked. Returns 0 if 315 * awakened, EWOULDBLOCK if the timeout expires. If PCATCH is set and a 316 * signal needs to be delivered, ERESTART is returned if the current system 317 * call should be restarted if possible, and EINTR is returned if the system 318 * call should be interrupted by the signal (return EINTR). 319 * 320 * Note that if we are a process, we release_curproc() before messing with 321 * the LWKT scheduler. 322 * 323 * During autoconfiguration or after a panic, a sleep will simply 324 * lower the priority briefly to allow interrupts, then return. 325 */ 326 int 327 tsleep(void *ident, int flags, const char *wmesg, int timo) 328 { 329 struct thread *td = curthread; 330 struct proc *p = td->td_proc; /* may be NULL */ 331 globaldata_t gd; 332 int sig; 333 int catch; 334 int id; 335 int error; 336 int oldpri; 337 struct callout thandle; 338 339 /* 340 * NOTE: removed KTRPOINT, it could cause races due to blocking 341 * even in stable. Just scrap it for now. 342 */ 343 if (cold || panicstr) { 344 /* 345 * After a panic, or during autoconfiguration, 346 * just give interrupts a chance, then just return; 347 * don't run any other procs or panic below, 348 * in case this is the idle process and already asleep. 349 */ 350 splz(); 351 oldpri = td->td_pri & TDPRI_MASK; 352 lwkt_setpri_self(safepri); 353 lwkt_switch(); 354 lwkt_setpri_self(oldpri); 355 return (0); 356 } 357 logtsleep(tsleep_beg); 358 gd = td->td_gd; 359 KKASSERT(td != &gd->gd_idlethread); /* you must be kidding! */ 360 361 /* 362 * NOTE: all of this occurs on the current cpu, including any 363 * callout-based wakeups, so a critical section is a sufficient 364 * interlock. 365 * 366 * The entire sequence through to where we actually sleep must 367 * run without breaking the critical section. 368 */ 369 id = LOOKUP(ident); 370 catch = flags & PCATCH; 371 error = 0; 372 sig = 0; 373 374 crit_enter_quick(td); 375 376 KASSERT(ident != NULL, ("tsleep: no ident")); 377 KASSERT(p == NULL || p->p_stat == SRUN, ("tsleep %p %s %d", 378 ident, wmesg, p->p_stat)); 379 380 /* 381 * Setup for the current process (if this is a process). 382 */ 383 if (p) { 384 if (catch) { 385 /* 386 * Early termination if PCATCH was set and a 387 * signal is pending, interlocked with the 388 * critical section. 389 * 390 * Early termination only occurs when tsleep() is 391 * entered while in a normal SRUN state. 392 */ 393 if ((sig = CURSIG(p)) != 0) 394 goto resume; 395 396 /* 397 * Causes psignal to wake us up when. 398 */ 399 p->p_flag |= P_SINTR; 400 } 401 402 /* 403 * Make sure the current process has been untangled from 404 * the userland scheduler and initialize slptime to start 405 * counting. 406 */ 407 if (flags & PNORESCHED) 408 td->td_flags |= TDF_NORESCHED; 409 p->p_usched->release_curproc(&p->p_lwp); 410 p->p_slptime = 0; 411 } 412 413 /* 414 * Move our thread to the correct queue and setup our wchan, etc. 415 */ 416 lwkt_deschedule_self(td); 417 td->td_flags |= TDF_TSLEEPQ; 418 TAILQ_INSERT_TAIL(&gd->gd_tsleep_hash[id], td, td_threadq); 419 atomic_set_int(&slpque_cpumasks[id], gd->gd_cpumask); 420 421 td->td_wchan = ident; 422 td->td_wmesg = wmesg; 423 td->td_wdomain = flags & PDOMAIN_MASK; 424 425 /* 426 * Setup the timeout, if any 427 */ 428 if (timo) { 429 callout_init(&thandle); 430 callout_reset(&thandle, timo, endtsleep, td); 431 } 432 433 /* 434 * Beddy bye bye. 435 */ 436 if (p) { 437 /* 438 * Ok, we are sleeping. Place us in the SSLEEP state. 439 */ 440 KKASSERT((p->p_flag & P_ONRUNQ) == 0); 441 p->p_stat = SSLEEP; 442 p->p_stats->p_ru.ru_nvcsw++; 443 lwkt_switch(); 444 p->p_stat = SRUN; 445 } else { 446 lwkt_switch(); 447 } 448 449 /* 450 * Make sure we haven't switched cpus while we were asleep. It's 451 * not supposed to happen. Cleanup our temporary flags. 452 */ 453 KKASSERT(gd == td->td_gd); 454 td->td_flags &= ~TDF_NORESCHED; 455 456 /* 457 * Cleanup the timeout. 458 */ 459 if (timo) { 460 if (td->td_flags & TDF_TIMEOUT) { 461 td->td_flags &= ~TDF_TIMEOUT; 462 if (sig == 0) 463 error = EWOULDBLOCK; 464 } else { 465 callout_stop(&thandle); 466 } 467 } 468 469 /* 470 * Since td_threadq is used both for our run queue AND for the 471 * tsleep hash queue, we can't still be on it at this point because 472 * we've gotten cpu back. 473 */ 474 KASSERT((td->td_flags & TDF_TSLEEPQ) == 0, ("tsleep: impossible thread flags %08x", td->td_flags)); 475 td->td_wchan = NULL; 476 td->td_wmesg = NULL; 477 td->td_wdomain = 0; 478 479 /* 480 * Figure out the correct error return 481 */ 482 resume: 483 if (p) { 484 p->p_flag &= ~(P_BREAKTSLEEP | P_SINTR); 485 if (catch && error == 0 && (sig != 0 || (sig = CURSIG(p)))) { 486 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig)) 487 error = EINTR; 488 else 489 error = ERESTART; 490 } 491 } 492 logtsleep(tsleep_end); 493 crit_exit_quick(td); 494 return (error); 495 } 496 497 /* 498 * This is a dandy function that allows us to interlock tsleep/wakeup 499 * operations with unspecified upper level locks, such as lockmgr locks, 500 * simply by holding a critical section. The sequence is: 501 * 502 * (enter critical section) 503 * (acquire upper level lock) 504 * tsleep_interlock(blah) 505 * (release upper level lock) 506 * tsleep(blah, ...) 507 * (exit critical section) 508 * 509 * Basically this function sets our cpumask for the ident which informs 510 * other cpus that our cpu 'might' be waiting (or about to wait on) the 511 * hash index related to the ident. The critical section prevents another 512 * cpu's wakeup() from being processed on our cpu until we are actually 513 * able to enter the tsleep(). Thus, no race occurs between our attempt 514 * to release a resource and sleep, and another cpu's attempt to acquire 515 * a resource and call wakeup. 516 * 517 * There isn't much of a point to this function unless you call it while 518 * holding a critical section. 519 */ 520 static __inline void 521 _tsleep_interlock(globaldata_t gd, void *ident) 522 { 523 int id = LOOKUP(ident); 524 525 atomic_set_int(&slpque_cpumasks[id], gd->gd_cpumask); 526 } 527 528 void 529 tsleep_interlock(void *ident) 530 { 531 _tsleep_interlock(mycpu, ident); 532 } 533 534 /* 535 * Interlocked spinlock sleep. An exclusively held spinlock must 536 * be passed to msleep(). The function will atomically release the 537 * spinlock and tsleep on the ident, then reacquire the spinlock and 538 * return. 539 * 540 * This routine is fairly important along the critical path, so optimize it 541 * heavily. 542 */ 543 int 544 msleep(void *ident, struct spinlock *spin, int flags, 545 const char *wmesg, int timo) 546 { 547 globaldata_t gd = mycpu; 548 int error; 549 550 crit_enter_gd(gd); 551 _tsleep_interlock(gd, ident); 552 spin_unlock_wr_quick(gd, spin); 553 error = tsleep(ident, flags, wmesg, timo); 554 spin_lock_wr_quick(gd, spin); 555 crit_exit_gd(gd); 556 557 return (error); 558 } 559 560 /* 561 * Implement the timeout for tsleep. 562 * 563 * We set P_BREAKTSLEEP to indicate that an event has occured, but 564 * we only call setrunnable if the process is not stopped. 565 * 566 * This type of callout timeout is scheduled on the same cpu the process 567 * is sleeping on. Also, at the moment, the MP lock is held. 568 */ 569 static void 570 endtsleep(void *arg) 571 { 572 thread_t td = arg; 573 struct proc *p; 574 575 ASSERT_MP_LOCK_HELD(curthread); 576 crit_enter(); 577 578 /* 579 * cpu interlock. Thread flags are only manipulated on 580 * the cpu owning the thread. proc flags are only manipulated 581 * by the older of the MP lock. We have both. 582 */ 583 if (td->td_flags & TDF_TSLEEPQ) { 584 td->td_flags |= TDF_TIMEOUT; 585 586 if ((p = td->td_proc) != NULL) { 587 p->p_flag |= P_BREAKTSLEEP; 588 if ((p->p_flag & P_STOPPED) == 0) 589 setrunnable(p); 590 } else { 591 unsleep_and_wakeup_thread(td); 592 } 593 } 594 crit_exit(); 595 } 596 597 /* 598 * Unsleep and wakeup a thread. This function runs without the MP lock 599 * which means that it can only manipulate thread state on the owning cpu, 600 * and cannot touch the process state at all. 601 */ 602 static 603 void 604 unsleep_and_wakeup_thread(struct thread *td) 605 { 606 globaldata_t gd = mycpu; 607 int id; 608 609 #ifdef SMP 610 if (td->td_gd != gd) { 611 lwkt_send_ipiq(td->td_gd, (ipifunc1_t)unsleep_and_wakeup_thread, td); 612 return; 613 } 614 #endif 615 crit_enter(); 616 if (td->td_flags & TDF_TSLEEPQ) { 617 td->td_flags &= ~TDF_TSLEEPQ; 618 id = LOOKUP(td->td_wchan); 619 TAILQ_REMOVE(&gd->gd_tsleep_hash[id], td, td_threadq); 620 if (TAILQ_FIRST(&gd->gd_tsleep_hash[id]) == NULL) 621 atomic_clear_int(&slpque_cpumasks[id], gd->gd_cpumask); 622 lwkt_schedule(td); 623 } 624 crit_exit(); 625 } 626 627 /* 628 * Make all processes sleeping on the specified identifier runnable. 629 * count may be zero or one only. 630 * 631 * The domain encodes the sleep/wakeup domain AND the first cpu to check 632 * (which is always the current cpu). As we iterate across cpus 633 * 634 * This call may run without the MP lock held. We can only manipulate thread 635 * state on the cpu owning the thread. We CANNOT manipulate process state 636 * at all. 637 */ 638 static void 639 _wakeup(void *ident, int domain) 640 { 641 struct tslpque *qp; 642 struct thread *td; 643 struct thread *ntd; 644 globaldata_t gd; 645 #ifdef SMP 646 cpumask_t mask; 647 cpumask_t tmask; 648 int startcpu; 649 int nextcpu; 650 #endif 651 int id; 652 653 crit_enter(); 654 logtsleep(wakeup_beg); 655 gd = mycpu; 656 id = LOOKUP(ident); 657 qp = &gd->gd_tsleep_hash[id]; 658 restart: 659 for (td = TAILQ_FIRST(qp); td != NULL; td = ntd) { 660 ntd = TAILQ_NEXT(td, td_threadq); 661 if (td->td_wchan == ident && 662 td->td_wdomain == (domain & PDOMAIN_MASK) 663 ) { 664 KKASSERT(td->td_flags & TDF_TSLEEPQ); 665 td->td_flags &= ~TDF_TSLEEPQ; 666 TAILQ_REMOVE(qp, td, td_threadq); 667 if (TAILQ_FIRST(qp) == NULL) { 668 atomic_clear_int(&slpque_cpumasks[id], 669 gd->gd_cpumask); 670 } 671 lwkt_schedule(td); 672 if (domain & PWAKEUP_ONE) 673 goto done; 674 goto restart; 675 } 676 } 677 678 #ifdef SMP 679 /* 680 * We finished checking the current cpu but there still may be 681 * more work to do. Either wakeup_one was requested and no matching 682 * thread was found, or a normal wakeup was requested and we have 683 * to continue checking cpus. 684 * 685 * The cpu that started the wakeup sequence is encoded in the domain. 686 * We use this information to determine which cpus still need to be 687 * checked, locate a candidate cpu, and chain the wakeup 688 * asynchronously with an IPI message. 689 * 690 * It should be noted that this scheme is actually less expensive then 691 * the old scheme when waking up multiple threads, since we send 692 * only one IPI message per target candidate which may then schedule 693 * multiple threads. Before we could have wound up sending an IPI 694 * message for each thread on the target cpu (!= current cpu) that 695 * needed to be woken up. 696 * 697 * NOTE: Wakeups occuring on remote cpus are asynchronous. This 698 * should be ok since we are passing idents in the IPI rather then 699 * thread pointers. 700 */ 701 if ((domain & PWAKEUP_MYCPU) == 0 && 702 (mask = slpque_cpumasks[id]) != 0 703 ) { 704 /* 705 * Look for a cpu that might have work to do. Mask out cpus 706 * which have already been processed. 707 * 708 * 31xxxxxxxxxxxxxxxxxxxxxxxxxxxxx0 709 * ^ ^ ^ 710 * start currentcpu start 711 * case2 case1 712 * * * * 713 * 11111111111111110000000000000111 case1 714 * 00000000111111110000000000000000 case2 715 * 716 * case1: We started at start_case1 and processed through 717 * to the current cpu. We have to check any bits 718 * after the current cpu, then check bits before 719 * the starting cpu. 720 * 721 * case2: We have already checked all the bits from 722 * start_case2 to the end, and from 0 to the current 723 * cpu. We just have the bits from the current cpu 724 * to start_case2 left to check. 725 */ 726 startcpu = PWAKEUP_DECODE(domain); 727 if (gd->gd_cpuid >= startcpu) { 728 /* 729 * CASE1 730 */ 731 tmask = mask & ~((gd->gd_cpumask << 1) - 1); 732 if (mask & tmask) { 733 nextcpu = bsfl(mask & tmask); 734 lwkt_send_ipiq2(globaldata_find(nextcpu), 735 _wakeup, ident, domain); 736 } else { 737 tmask = (1 << startcpu) - 1; 738 if (mask & tmask) { 739 nextcpu = bsfl(mask & tmask); 740 lwkt_send_ipiq2( 741 globaldata_find(nextcpu), 742 _wakeup, ident, domain); 743 } 744 } 745 } else { 746 /* 747 * CASE2 748 */ 749 tmask = ~((gd->gd_cpumask << 1) - 1) & 750 ((1 << startcpu) - 1); 751 if (mask & tmask) { 752 nextcpu = bsfl(mask & tmask); 753 lwkt_send_ipiq2(globaldata_find(nextcpu), 754 _wakeup, ident, domain); 755 } 756 } 757 } 758 #endif 759 done: 760 logtsleep(wakeup_end); 761 crit_exit(); 762 } 763 764 /* 765 * Wakeup all threads tsleep()ing on the specified ident, on all cpus 766 */ 767 void 768 wakeup(void *ident) 769 { 770 _wakeup(ident, PWAKEUP_ENCODE(0, mycpu->gd_cpuid)); 771 } 772 773 /* 774 * Wakeup one thread tsleep()ing on the specified ident, on any cpu. 775 */ 776 void 777 wakeup_one(void *ident) 778 { 779 /* XXX potentially round-robin the first responding cpu */ 780 _wakeup(ident, PWAKEUP_ENCODE(0, mycpu->gd_cpuid) | PWAKEUP_ONE); 781 } 782 783 /* 784 * Wakeup threads tsleep()ing on the specified ident on the current cpu 785 * only. 786 */ 787 void 788 wakeup_mycpu(void *ident) 789 { 790 _wakeup(ident, PWAKEUP_MYCPU); 791 } 792 793 /* 794 * Wakeup one thread tsleep()ing on the specified ident on the current cpu 795 * only. 796 */ 797 void 798 wakeup_mycpu_one(void *ident) 799 { 800 /* XXX potentially round-robin the first responding cpu */ 801 _wakeup(ident, PWAKEUP_MYCPU|PWAKEUP_ONE); 802 } 803 804 /* 805 * Wakeup all thread tsleep()ing on the specified ident on the specified cpu 806 * only. 807 */ 808 void 809 wakeup_oncpu(globaldata_t gd, void *ident) 810 { 811 #ifdef SMP 812 if (gd == mycpu) { 813 _wakeup(ident, PWAKEUP_MYCPU); 814 } else { 815 lwkt_send_ipiq2(gd, _wakeup, ident, PWAKEUP_MYCPU); 816 } 817 #else 818 _wakeup(ident, PWAKEUP_MYCPU); 819 #endif 820 } 821 822 /* 823 * Wakeup one thread tsleep()ing on the specified ident on the specified cpu 824 * only. 825 */ 826 void 827 wakeup_oncpu_one(globaldata_t gd, void *ident) 828 { 829 #ifdef SMP 830 if (gd == mycpu) { 831 _wakeup(ident, PWAKEUP_MYCPU | PWAKEUP_ONE); 832 } else { 833 lwkt_send_ipiq2(gd, _wakeup, ident, PWAKEUP_MYCPU | PWAKEUP_ONE); 834 } 835 #else 836 _wakeup(ident, PWAKEUP_MYCPU | PWAKEUP_ONE); 837 #endif 838 } 839 840 /* 841 * Wakeup all threads waiting on the specified ident that slept using 842 * the specified domain, on all cpus. 843 */ 844 void 845 wakeup_domain(void *ident, int domain) 846 { 847 _wakeup(ident, PWAKEUP_ENCODE(domain, mycpu->gd_cpuid)); 848 } 849 850 /* 851 * Wakeup one thread waiting on the specified ident that slept using 852 * the specified domain, on any cpu. 853 */ 854 void 855 wakeup_domain_one(void *ident, int domain) 856 { 857 /* XXX potentially round-robin the first responding cpu */ 858 _wakeup(ident, PWAKEUP_ENCODE(domain, mycpu->gd_cpuid) | PWAKEUP_ONE); 859 } 860 861 /* 862 * setrunnable() 863 * 864 * Make a process runnable. The MP lock must be held on call. This only 865 * has an effect if we are in SSLEEP. We only break out of the 866 * tsleep if P_BREAKTSLEEP is set, otherwise we just fix-up the state. 867 * 868 * NOTE: With the MP lock held we can only safely manipulate the process 869 * structure. We cannot safely manipulate the thread structure. 870 */ 871 void 872 setrunnable(struct proc *p) 873 { 874 crit_enter(); 875 ASSERT_MP_LOCK_HELD(curthread); 876 p->p_flag &= ~P_STOPPED; 877 if (p->p_stat == SSLEEP && (p->p_flag & P_BREAKTSLEEP)) { 878 unsleep_and_wakeup_thread(p->p_thread); 879 } 880 crit_exit(); 881 } 882 883 /* 884 * The process is stopped due to some condition, usually because P_STOPPED 885 * is set but also possibly due to being traced. 886 * 887 * NOTE! If the caller sets P_STOPPED, the caller must also clear P_WAITED 888 * because the parent may check the child's status before the child actually 889 * gets to this routine. 890 * 891 * This routine is called with the current process only, typically just 892 * before returning to userland. 893 * 894 * Setting P_BREAKTSLEEP before entering the tsleep will cause a passive 895 * SIGCONT to break out of the tsleep. 896 */ 897 void 898 tstop(struct proc *p) 899 { 900 wakeup((caddr_t)p->p_pptr); 901 p->p_flag |= P_BREAKTSLEEP; 902 tsleep(p, 0, "stop", 0); 903 } 904 905 /* 906 * Yield / synchronous reschedule. This is a bit tricky because the trap 907 * code might have set a lazy release on the switch function. Setting 908 * P_PASSIVE_ACQ will ensure that the lazy release executes when we call 909 * switch, and that we are given a greater chance of affinity with our 910 * current cpu. 911 * 912 * We call lwkt_setpri_self() to rotate our thread to the end of the lwkt 913 * run queue. lwkt_switch() will also execute any assigned passive release 914 * (which usually calls release_curproc()), allowing a same/higher priority 915 * process to be designated as the current process. 916 * 917 * While it is possible for a lower priority process to be designated, 918 * it's call to lwkt_maybe_switch() in acquire_curproc() will likely 919 * round-robin back to us and we will be able to re-acquire the current 920 * process designation. 921 */ 922 void 923 uio_yield(void) 924 { 925 struct thread *td = curthread; 926 struct proc *p = td->td_proc; 927 928 lwkt_setpri_self(td->td_pri & TDPRI_MASK); 929 if (p) { 930 p->p_flag |= P_PASSIVE_ACQ; 931 lwkt_switch(); 932 p->p_flag &= ~P_PASSIVE_ACQ; 933 } else { 934 lwkt_switch(); 935 } 936 } 937 938 /* 939 * Compute a tenex style load average of a quantity on 940 * 1, 5 and 15 minute intervals. 941 */ 942 static int loadav_count_runnable(struct proc *p, void *data); 943 944 static void 945 loadav(void *arg) 946 { 947 struct loadavg *avg; 948 int i, nrun; 949 950 nrun = 0; 951 allproc_scan(loadav_count_runnable, &nrun); 952 avg = &averunnable; 953 for (i = 0; i < 3; i++) { 954 avg->ldavg[i] = (cexp[i] * avg->ldavg[i] + 955 nrun * FSCALE * (FSCALE - cexp[i])) >> FSHIFT; 956 } 957 958 /* 959 * Schedule the next update to occur after 5 seconds, but add a 960 * random variation to avoid synchronisation with processes that 961 * run at regular intervals. 962 */ 963 callout_reset(&loadav_callout, hz * 4 + (int)(random() % (hz * 2 + 1)), 964 loadav, NULL); 965 } 966 967 static int 968 loadav_count_runnable(struct proc *p, void *data) 969 { 970 int *nrunp = data; 971 thread_t td; 972 973 switch (p->p_stat) { 974 case SRUN: 975 if ((td = p->p_thread) == NULL) 976 break; 977 if (td->td_flags & TDF_BLOCKED) 978 break; 979 /* fall through */ 980 case SIDL: 981 ++*nrunp; 982 break; 983 default: 984 break; 985 } 986 return(0); 987 } 988 989 /* ARGSUSED */ 990 static void 991 sched_setup(void *dummy) 992 { 993 callout_init(&loadav_callout); 994 callout_init(&schedcpu_callout); 995 996 /* Kick off timeout driven events by calling first time. */ 997 schedcpu(NULL); 998 loadav(NULL); 999 } 1000 1001