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 1.91 2008/09/09 04:06:13 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 p->p_usched->release_curproc(lp); 441 lp->lwp_slptime = 0; 442 } 443 444 /* 445 * Move our thread to the correct queue and setup our wchan, etc. 446 */ 447 lwkt_deschedule_self(td); 448 td->td_flags |= TDF_TSLEEPQ; 449 TAILQ_INSERT_TAIL(&gd->gd_tsleep_hash[id], td, td_threadq); 450 atomic_set_int(&slpque_cpumasks[id], gd->gd_cpumask); 451 452 td->td_wchan = ident; 453 td->td_wmesg = wmesg; 454 td->td_wdomain = flags & PDOMAIN_MASK; 455 456 /* 457 * Setup the timeout, if any 458 */ 459 if (timo) { 460 callout_init(&thandle); 461 callout_reset(&thandle, timo, endtsleep, td); 462 } 463 464 /* 465 * Beddy bye bye. 466 */ 467 if (lp) { 468 /* 469 * Ok, we are sleeping. Place us in the SSLEEP state. 470 */ 471 KKASSERT((lp->lwp_flag & LWP_ONRUNQ) == 0); 472 /* 473 * tstop() sets LSSTOP, so don't fiddle with that. 474 */ 475 if (lp->lwp_stat != LSSTOP) 476 lp->lwp_stat = LSSLEEP; 477 lp->lwp_ru.ru_nvcsw++; 478 lwkt_switch(); 479 480 /* 481 * And when we are woken up, put us back in LSRUN. If we 482 * slept for over a second, recalculate our estcpu. 483 */ 484 lp->lwp_stat = LSRUN; 485 if (lp->lwp_slptime) 486 p->p_usched->recalculate(lp); 487 lp->lwp_slptime = 0; 488 } else { 489 lwkt_switch(); 490 } 491 492 /* 493 * Make sure we haven't switched cpus while we were asleep. It's 494 * not supposed to happen. Cleanup our temporary flags. 495 */ 496 KKASSERT(gd == td->td_gd); 497 498 /* 499 * Cleanup the timeout. 500 */ 501 if (timo) { 502 if (td->td_flags & TDF_TIMEOUT) { 503 td->td_flags &= ~TDF_TIMEOUT; 504 error = EWOULDBLOCK; 505 } else { 506 callout_stop(&thandle); 507 } 508 } 509 510 /* 511 * Since td_threadq is used both for our run queue AND for the 512 * tsleep hash queue, we can't still be on it at this point because 513 * we've gotten cpu back. 514 */ 515 KASSERT((td->td_flags & TDF_TSLEEPQ) == 0, ("tsleep: impossible thread flags %08x", td->td_flags)); 516 td->td_wchan = NULL; 517 td->td_wmesg = NULL; 518 td->td_wdomain = 0; 519 520 /* 521 * Figure out the correct error return. If interrupted by a 522 * signal we want to return EINTR or ERESTART. 523 * 524 * If P_MAILBOX is set no automatic system call restart occurs 525 * and we return EINTR. P_MAILBOX is meant to be used as an 526 * interlock, the user must poll it prior to any system call 527 * that it wishes to interlock a mailbox signal against since 528 * the flag is cleared on *any* system call that sleeps. 529 */ 530 resume: 531 if (p) { 532 if (catch && error == 0) { 533 if ((p->p_flag & P_MAILBOX) && sig == 0) { 534 error = EINTR; 535 } else if (sig != 0 || (sig = CURSIG(lp))) { 536 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig)) 537 error = EINTR; 538 else 539 error = ERESTART; 540 } 541 } 542 lp->lwp_flag &= ~(LWP_BREAKTSLEEP | LWP_SINTR); 543 p->p_flag &= ~P_MAILBOX; 544 } 545 logtsleep1(tsleep_end); 546 crit_exit_quick(td); 547 return (error); 548 } 549 550 /* 551 * This is a dandy function that allows us to interlock tsleep/wakeup 552 * operations with unspecified upper level locks, such as lockmgr locks, 553 * simply by holding a critical section. The sequence is: 554 * 555 * (enter critical section) 556 * (acquire upper level lock) 557 * tsleep_interlock(blah) 558 * (release upper level lock) 559 * tsleep(blah, ...) 560 * (exit critical section) 561 * 562 * Basically this function sets our cpumask for the ident which informs 563 * other cpus that our cpu 'might' be waiting (or about to wait on) the 564 * hash index related to the ident. The critical section prevents another 565 * cpu's wakeup() from being processed on our cpu until we are actually 566 * able to enter the tsleep(). Thus, no race occurs between our attempt 567 * to release a resource and sleep, and another cpu's attempt to acquire 568 * a resource and call wakeup. 569 * 570 * There isn't much of a point to this function unless you call it while 571 * holding a critical section. 572 */ 573 static __inline void 574 _tsleep_interlock(globaldata_t gd, void *ident) 575 { 576 int id = LOOKUP(ident); 577 578 atomic_set_int(&slpque_cpumasks[id], gd->gd_cpumask); 579 } 580 581 void 582 tsleep_interlock(void *ident) 583 { 584 _tsleep_interlock(mycpu, ident); 585 } 586 587 /* 588 * Interlocked spinlock sleep. An exclusively held spinlock must 589 * be passed to msleep(). The function will atomically release the 590 * spinlock and tsleep on the ident, then reacquire the spinlock and 591 * return. 592 * 593 * This routine is fairly important along the critical path, so optimize it 594 * heavily. 595 */ 596 int 597 msleep(void *ident, struct spinlock *spin, int flags, 598 const char *wmesg, int timo) 599 { 600 globaldata_t gd = mycpu; 601 int error; 602 603 crit_enter_gd(gd); 604 _tsleep_interlock(gd, ident); 605 spin_unlock_wr_quick(gd, spin); 606 error = tsleep(ident, flags, wmesg, timo); 607 spin_lock_wr_quick(gd, spin); 608 crit_exit_gd(gd); 609 610 return (error); 611 } 612 613 /* 614 * Interlocked serializer sleep. An exclusively held serializer must 615 * be passed to serialize_sleep(). The function will atomically release 616 * the serializer and tsleep on the ident, then reacquire the serializer 617 * and return. 618 */ 619 int 620 serialize_sleep(void *ident, struct lwkt_serialize *slz, int flags, 621 const char *wmesg, int timo) 622 { 623 int ret; 624 625 ASSERT_SERIALIZED(slz); 626 627 crit_enter(); 628 tsleep_interlock(ident); 629 lwkt_serialize_exit(slz); 630 ret = tsleep(ident, flags, wmesg, timo); 631 lwkt_serialize_enter(slz); 632 crit_exit(); 633 634 return ret; 635 } 636 637 /* 638 * Directly block on the LWKT thread by descheduling it. This 639 * is much faster then tsleep(), but the only legal way to wake 640 * us up is to directly schedule the thread. 641 * 642 * Setting TDF_SINTR will cause new signals to directly schedule us. 643 * 644 * This routine is typically called while in a critical section. 645 */ 646 int 647 lwkt_sleep(const char *wmesg, int flags) 648 { 649 thread_t td = curthread; 650 int sig; 651 652 if ((flags & PCATCH) == 0 || td->td_lwp == NULL) { 653 td->td_flags |= TDF_BLOCKED; 654 td->td_wmesg = wmesg; 655 lwkt_deschedule_self(td); 656 lwkt_switch(); 657 td->td_wmesg = NULL; 658 td->td_flags &= ~TDF_BLOCKED; 659 return(0); 660 } 661 if ((sig = CURSIG(td->td_lwp)) != 0) { 662 if (SIGISMEMBER(td->td_proc->p_sigacts->ps_sigintr, sig)) 663 return(EINTR); 664 else 665 return(ERESTART); 666 667 } 668 td->td_flags |= TDF_BLOCKED | TDF_SINTR; 669 td->td_wmesg = wmesg; 670 lwkt_deschedule_self(td); 671 lwkt_switch(); 672 td->td_flags &= ~(TDF_BLOCKED | TDF_SINTR); 673 td->td_wmesg = NULL; 674 return(0); 675 } 676 677 /* 678 * Implement the timeout for tsleep. 679 * 680 * We set LWP_BREAKTSLEEP to indicate that an event has occured, but 681 * we only call setrunnable if the process is not stopped. 682 * 683 * This type of callout timeout is scheduled on the same cpu the process 684 * is sleeping on. Also, at the moment, the MP lock is held. 685 */ 686 static void 687 endtsleep(void *arg) 688 { 689 thread_t td = arg; 690 struct lwp *lp; 691 692 ASSERT_MP_LOCK_HELD(curthread); 693 crit_enter(); 694 695 /* 696 * cpu interlock. Thread flags are only manipulated on 697 * the cpu owning the thread. proc flags are only manipulated 698 * by the older of the MP lock. We have both. 699 */ 700 if (td->td_flags & TDF_TSLEEPQ) { 701 td->td_flags |= TDF_TIMEOUT; 702 703 if ((lp = td->td_lwp) != NULL) { 704 lp->lwp_flag |= LWP_BREAKTSLEEP; 705 if (lp->lwp_proc->p_stat != SSTOP) 706 setrunnable(lp); 707 } else { 708 unsleep_and_wakeup_thread(td); 709 } 710 } 711 crit_exit(); 712 } 713 714 /* 715 * Unsleep and wakeup a thread. This function runs without the MP lock 716 * which means that it can only manipulate thread state on the owning cpu, 717 * and cannot touch the process state at all. 718 */ 719 static 720 void 721 unsleep_and_wakeup_thread(struct thread *td) 722 { 723 globaldata_t gd = mycpu; 724 int id; 725 726 #ifdef SMP 727 if (td->td_gd != gd) { 728 lwkt_send_ipiq(td->td_gd, (ipifunc1_t)unsleep_and_wakeup_thread, td); 729 return; 730 } 731 #endif 732 crit_enter(); 733 if (td->td_flags & TDF_TSLEEPQ) { 734 td->td_flags &= ~TDF_TSLEEPQ; 735 id = LOOKUP(td->td_wchan); 736 TAILQ_REMOVE(&gd->gd_tsleep_hash[id], td, td_threadq); 737 if (TAILQ_FIRST(&gd->gd_tsleep_hash[id]) == NULL) 738 atomic_clear_int(&slpque_cpumasks[id], gd->gd_cpumask); 739 lwkt_schedule(td); 740 } 741 crit_exit(); 742 } 743 744 /* 745 * Make all processes sleeping on the specified identifier runnable. 746 * count may be zero or one only. 747 * 748 * The domain encodes the sleep/wakeup domain AND the first cpu to check 749 * (which is always the current cpu). As we iterate across cpus 750 * 751 * This call may run without the MP lock held. We can only manipulate thread 752 * state on the cpu owning the thread. We CANNOT manipulate process state 753 * at all. 754 */ 755 static void 756 _wakeup(void *ident, int domain) 757 { 758 struct tslpque *qp; 759 struct thread *td; 760 struct thread *ntd; 761 globaldata_t gd; 762 #ifdef SMP 763 cpumask_t mask; 764 #endif 765 int id; 766 767 crit_enter(); 768 logtsleep2(wakeup_beg, ident); 769 gd = mycpu; 770 id = LOOKUP(ident); 771 qp = &gd->gd_tsleep_hash[id]; 772 restart: 773 for (td = TAILQ_FIRST(qp); td != NULL; td = ntd) { 774 ntd = TAILQ_NEXT(td, td_threadq); 775 if (td->td_wchan == ident && 776 td->td_wdomain == (domain & PDOMAIN_MASK) 777 ) { 778 KKASSERT(td->td_flags & TDF_TSLEEPQ); 779 td->td_flags &= ~TDF_TSLEEPQ; 780 TAILQ_REMOVE(qp, td, td_threadq); 781 if (TAILQ_FIRST(qp) == NULL) { 782 atomic_clear_int(&slpque_cpumasks[id], 783 gd->gd_cpumask); 784 } 785 lwkt_schedule(td); 786 if (domain & PWAKEUP_ONE) 787 goto done; 788 goto restart; 789 } 790 } 791 792 #ifdef SMP 793 /* 794 * We finished checking the current cpu but there still may be 795 * more work to do. Either wakeup_one was requested and no matching 796 * thread was found, or a normal wakeup was requested and we have 797 * to continue checking cpus. 798 * 799 * It should be noted that this scheme is actually less expensive then 800 * the old scheme when waking up multiple threads, since we send 801 * only one IPI message per target candidate which may then schedule 802 * multiple threads. Before we could have wound up sending an IPI 803 * message for each thread on the target cpu (!= current cpu) that 804 * needed to be woken up. 805 * 806 * NOTE: Wakeups occuring on remote cpus are asynchronous. This 807 * should be ok since we are passing idents in the IPI rather then 808 * thread pointers. 809 */ 810 if ((domain & PWAKEUP_MYCPU) == 0 && 811 (mask = slpque_cpumasks[id] & gd->gd_other_cpus) != 0) { 812 lwkt_send_ipiq2_mask(mask, _wakeup, ident, 813 domain | PWAKEUP_MYCPU); 814 } 815 #endif 816 done: 817 logtsleep1(wakeup_end); 818 crit_exit(); 819 } 820 821 /* 822 * Wakeup all threads tsleep()ing on the specified ident, on all cpus 823 */ 824 void 825 wakeup(void *ident) 826 { 827 _wakeup(ident, PWAKEUP_ENCODE(0, mycpu->gd_cpuid)); 828 } 829 830 /* 831 * Wakeup one thread tsleep()ing on the specified ident, on any cpu. 832 */ 833 void 834 wakeup_one(void *ident) 835 { 836 /* XXX potentially round-robin the first responding cpu */ 837 _wakeup(ident, PWAKEUP_ENCODE(0, mycpu->gd_cpuid) | PWAKEUP_ONE); 838 } 839 840 /* 841 * Wakeup threads tsleep()ing on the specified ident on the current cpu 842 * only. 843 */ 844 void 845 wakeup_mycpu(void *ident) 846 { 847 _wakeup(ident, PWAKEUP_MYCPU); 848 } 849 850 /* 851 * Wakeup one thread tsleep()ing on the specified ident on the current cpu 852 * only. 853 */ 854 void 855 wakeup_mycpu_one(void *ident) 856 { 857 /* XXX potentially round-robin the first responding cpu */ 858 _wakeup(ident, PWAKEUP_MYCPU|PWAKEUP_ONE); 859 } 860 861 /* 862 * Wakeup all thread tsleep()ing on the specified ident on the specified cpu 863 * only. 864 */ 865 void 866 wakeup_oncpu(globaldata_t gd, void *ident) 867 { 868 #ifdef SMP 869 if (gd == mycpu) { 870 _wakeup(ident, PWAKEUP_MYCPU); 871 } else { 872 lwkt_send_ipiq2(gd, _wakeup, ident, PWAKEUP_MYCPU); 873 } 874 #else 875 _wakeup(ident, PWAKEUP_MYCPU); 876 #endif 877 } 878 879 /* 880 * Wakeup one thread tsleep()ing on the specified ident on the specified cpu 881 * only. 882 */ 883 void 884 wakeup_oncpu_one(globaldata_t gd, void *ident) 885 { 886 #ifdef SMP 887 if (gd == mycpu) { 888 _wakeup(ident, PWAKEUP_MYCPU | PWAKEUP_ONE); 889 } else { 890 lwkt_send_ipiq2(gd, _wakeup, ident, PWAKEUP_MYCPU | PWAKEUP_ONE); 891 } 892 #else 893 _wakeup(ident, PWAKEUP_MYCPU | PWAKEUP_ONE); 894 #endif 895 } 896 897 /* 898 * Wakeup all threads waiting on the specified ident that slept using 899 * the specified domain, on all cpus. 900 */ 901 void 902 wakeup_domain(void *ident, int domain) 903 { 904 _wakeup(ident, PWAKEUP_ENCODE(domain, mycpu->gd_cpuid)); 905 } 906 907 /* 908 * Wakeup one thread waiting on the specified ident that slept using 909 * the specified domain, on any cpu. 910 */ 911 void 912 wakeup_domain_one(void *ident, int domain) 913 { 914 /* XXX potentially round-robin the first responding cpu */ 915 _wakeup(ident, PWAKEUP_ENCODE(domain, mycpu->gd_cpuid) | PWAKEUP_ONE); 916 } 917 918 /* 919 * setrunnable() 920 * 921 * Make a process runnable. The MP lock must be held on call. This only 922 * has an effect if we are in SSLEEP. We only break out of the 923 * tsleep if LWP_BREAKTSLEEP is set, otherwise we just fix-up the state. 924 * 925 * NOTE: With the MP lock held we can only safely manipulate the process 926 * structure. We cannot safely manipulate the thread structure. 927 */ 928 void 929 setrunnable(struct lwp *lp) 930 { 931 crit_enter(); 932 ASSERT_MP_LOCK_HELD(curthread); 933 if (lp->lwp_stat == LSSTOP) 934 lp->lwp_stat = LSSLEEP; 935 if (lp->lwp_stat == LSSLEEP && (lp->lwp_flag & LWP_BREAKTSLEEP)) 936 unsleep_and_wakeup_thread(lp->lwp_thread); 937 crit_exit(); 938 } 939 940 /* 941 * The process is stopped due to some condition, usually because p_stat is 942 * set to SSTOP, but also possibly due to being traced. 943 * 944 * NOTE! If the caller sets SSTOP, the caller must also clear P_WAITED 945 * because the parent may check the child's status before the child actually 946 * gets to this routine. 947 * 948 * This routine is called with the current lwp only, typically just 949 * before returning to userland. 950 * 951 * Setting LWP_BREAKTSLEEP before entering the tsleep will cause a passive 952 * SIGCONT to break out of the tsleep. 953 */ 954 void 955 tstop(void) 956 { 957 struct lwp *lp = curthread->td_lwp; 958 struct proc *p = lp->lwp_proc; 959 960 crit_enter(); 961 /* 962 * If LWP_WSTOP is set, we were sleeping 963 * while our process was stopped. At this point 964 * we were already counted as stopped. 965 */ 966 if ((lp->lwp_flag & LWP_WSTOP) == 0) { 967 /* 968 * If we're the last thread to stop, signal 969 * our parent. 970 */ 971 p->p_nstopped++; 972 lp->lwp_flag |= LWP_WSTOP; 973 wakeup(&p->p_nstopped); 974 if (p->p_nstopped == p->p_nthreads) { 975 p->p_flag &= ~P_WAITED; 976 wakeup(p->p_pptr); 977 if ((p->p_pptr->p_sigacts->ps_flag & PS_NOCLDSTOP) == 0) 978 ksignal(p->p_pptr, SIGCHLD); 979 } 980 } 981 while (p->p_stat == SSTOP) { 982 lp->lwp_flag |= LWP_BREAKTSLEEP; 983 lp->lwp_stat = LSSTOP; 984 tsleep(p, 0, "stop", 0); 985 } 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