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 1.52 2005/11/09 03:39:15 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 #ifdef KTRACE 55 #include <sys/uio.h> 56 #include <sys/ktrace.h> 57 #endif 58 #include <sys/xwait.h> 59 60 #include <machine/cpu.h> 61 #include <machine/ipl.h> 62 #include <machine/smp.h> 63 64 TAILQ_HEAD(tslpque, thread); 65 66 static void sched_setup (void *dummy); 67 SYSINIT(sched_setup, SI_SUB_KICK_SCHEDULER, SI_ORDER_FIRST, sched_setup, NULL) 68 69 int hogticks; 70 int lbolt; 71 int sched_quantum; /* Roundrobin scheduling quantum in ticks. */ 72 int ncpus; 73 int ncpus2, ncpus2_shift, ncpus2_mask; 74 int safepri; 75 76 static struct callout loadav_callout; 77 static struct callout schedcpu_callout; 78 MALLOC_DEFINE(M_TSLEEP, "tslpque", "tsleep queues"); 79 80 struct loadavg averunnable = 81 { {0, 0, 0}, FSCALE }; /* load average, of runnable procs */ 82 /* 83 * Constants for averages over 1, 5, and 15 minutes 84 * when sampling at 5 second intervals. 85 */ 86 static fixpt_t cexp[3] = { 87 0.9200444146293232 * FSCALE, /* exp(-1/12) */ 88 0.9834714538216174 * FSCALE, /* exp(-1/60) */ 89 0.9944598480048967 * FSCALE, /* exp(-1/180) */ 90 }; 91 92 static void endtsleep (void *); 93 static void loadav (void *arg); 94 static void schedcpu (void *arg); 95 96 /* 97 * Adjust the scheduler quantum. The quantum is specified in microseconds. 98 * Note that 'tick' is in microseconds per tick. 99 */ 100 static int 101 sysctl_kern_quantum(SYSCTL_HANDLER_ARGS) 102 { 103 int error, new_val; 104 105 new_val = sched_quantum * tick; 106 error = sysctl_handle_int(oidp, &new_val, 0, req); 107 if (error != 0 || req->newptr == NULL) 108 return (error); 109 if (new_val < tick) 110 return (EINVAL); 111 sched_quantum = new_val / tick; 112 hogticks = 2 * sched_quantum; 113 return (0); 114 } 115 116 SYSCTL_PROC(_kern, OID_AUTO, quantum, CTLTYPE_INT|CTLFLAG_RW, 117 0, sizeof sched_quantum, sysctl_kern_quantum, "I", ""); 118 119 /* 120 * If `ccpu' is not equal to `exp(-1/20)' and you still want to use the 121 * faster/more-accurate formula, you'll have to estimate CCPU_SHIFT below 122 * and possibly adjust FSHIFT in "param.h" so that (FSHIFT >= CCPU_SHIFT). 123 * 124 * To estimate CCPU_SHIFT for exp(-1/20), the following formula was used: 125 * 1 - exp(-1/20) ~= 0.0487 ~= 0.0488 == 1 (fixed pt, *11* bits). 126 * 127 * If you don't want to bother with the faster/more-accurate formula, you 128 * can set CCPU_SHIFT to (FSHIFT + 1) which will use a slower/less-accurate 129 * (more general) method of calculating the %age of CPU used by a process. 130 * 131 * decay 95% of `p_pctcpu' in 60 seconds; see CCPU_SHIFT before changing 132 */ 133 #define CCPU_SHIFT 11 134 135 static fixpt_t ccpu = 0.95122942450071400909 * FSCALE; /* exp(-1/20) */ 136 SYSCTL_INT(_kern, OID_AUTO, ccpu, CTLFLAG_RD, &ccpu, 0, ""); 137 138 /* 139 * kernel uses `FSCALE', userland (SHOULD) use kern.fscale 140 */ 141 static int fscale __unused = FSCALE; 142 SYSCTL_INT(_kern, OID_AUTO, fscale, CTLFLAG_RD, 0, FSCALE, ""); 143 144 /* 145 * Recompute process priorities, once a second. 146 * 147 * Since the userland schedulers are typically event oriented, if the 148 * estcpu calculation at wakeup() time is not sufficient to make a 149 * process runnable relative to other processes in the system we have 150 * a 1-second recalc to help out. 151 * 152 * This code also allows us to store sysclock_t data in the process structure 153 * without fear of an overrun, since sysclock_t are guarenteed to hold 154 * several seconds worth of count. 155 */ 156 /* ARGSUSED */ 157 static void 158 schedcpu(void *arg) 159 { 160 struct proc *p; 161 162 FOREACH_PROC_IN_SYSTEM(p) { 163 /* 164 * Increment time in/out of memory and sleep time 165 * (if sleeping). We ignore overflow; with 16-bit int's 166 * (remember them?) overflow takes 45 days. 167 */ 168 crit_enter(); 169 p->p_swtime++; 170 if (p->p_stat == SSLEEP || p->p_stat == SSTOP) 171 p->p_slptime++; 172 173 /* 174 * Only recalculate processes that are active or have slept 175 * less then 2 seconds. The schedulers understand this. 176 */ 177 if (p->p_slptime <= 1) { 178 p->p_usched->recalculate(&p->p_lwp); 179 } else { 180 p->p_pctcpu = (p->p_pctcpu * ccpu) >> FSHIFT; 181 } 182 crit_exit(); 183 } 184 wakeup((caddr_t)&lbolt); 185 callout_reset(&schedcpu_callout, hz, schedcpu, NULL); 186 } 187 188 /* 189 * This is only used by ps. Generate a cpu percentage use over 190 * a period of one second. 191 */ 192 void 193 updatepcpu(struct lwp *lp, int cpticks, int ttlticks) 194 { 195 fixpt_t acc; 196 int remticks; 197 198 acc = (cpticks << FSHIFT) / ttlticks; 199 if (ttlticks >= ESTCPUFREQ) { 200 lp->lwp_pctcpu = acc; 201 } else { 202 remticks = ESTCPUFREQ - ttlticks; 203 lp->lwp_pctcpu = (acc * ttlticks + lp->lwp_pctcpu * remticks) / 204 ESTCPUFREQ; 205 } 206 } 207 208 /* 209 * We're only looking at 7 bits of the address; everything is 210 * aligned to 4, lots of things are aligned to greater powers 211 * of 2. Shift right by 8, i.e. drop the bottom 256 worth. 212 */ 213 #define TABLESIZE 128 214 #define LOOKUP(x) (((intptr_t)(x) >> 8) & (TABLESIZE - 1)) 215 216 static cpumask_t slpque_cpumasks[TABLESIZE]; 217 218 /* 219 * General scheduler initialization. We force a reschedule 25 times 220 * a second by default. Note that cpu0 is initialized in early boot and 221 * cannot make any high level calls. 222 * 223 * Each cpu has its own sleep queue. 224 */ 225 void 226 sleep_gdinit(globaldata_t gd) 227 { 228 static struct tslpque slpque_cpu0[TABLESIZE]; 229 int i; 230 231 if (gd->gd_cpuid == 0) { 232 sched_quantum = (hz + 24) / 25; 233 hogticks = 2 * sched_quantum; 234 235 gd->gd_tsleep_hash = slpque_cpu0; 236 } else { 237 #if 0 238 gd->gd_tsleep_hash = malloc(sizeof(slpque_cpu0), 239 M_TSLEEP, M_WAITOK | M_ZERO); 240 #endif 241 gd->gd_tsleep_hash = slpque_cpu0; 242 } 243 for (i = 0; i < TABLESIZE; ++i) 244 TAILQ_INIT(&gd->gd_tsleep_hash[i]); 245 } 246 247 /* 248 * General sleep call. Suspends the current process until a wakeup is 249 * performed on the specified identifier. The process will then be made 250 * runnable with the specified priority. Sleeps at most timo/hz seconds 251 * (0 means no timeout). If flags includes PCATCH flag, signals are checked 252 * before and after sleeping, else signals are not checked. Returns 0 if 253 * awakened, EWOULDBLOCK if the timeout expires. If PCATCH is set and a 254 * signal needs to be delivered, ERESTART is returned if the current system 255 * call should be restarted if possible, and EINTR is returned if the system 256 * call should be interrupted by the signal (return EINTR). 257 * 258 * Note that if we are a process, we release_curproc() before messing with 259 * the LWKT scheduler. 260 * 261 * During autoconfiguration or after a panic, a sleep will simply 262 * lower the priority briefly to allow interrupts, then return. 263 */ 264 int 265 tsleep(void *ident, int flags, const char *wmesg, int timo) 266 { 267 struct thread *td = curthread; 268 struct proc *p = td->td_proc; /* may be NULL */ 269 globaldata_t gd; 270 int sig = 0, catch = flags & PCATCH; 271 int id = LOOKUP(ident); 272 int oldpri; 273 struct callout thandle; 274 275 /* 276 * NOTE: removed KTRPOINT, it could cause races due to blocking 277 * even in stable. Just scrap it for now. 278 */ 279 if (cold || panicstr) { 280 /* 281 * After a panic, or during autoconfiguration, 282 * just give interrupts a chance, then just return; 283 * don't run any other procs or panic below, 284 * in case this is the idle process and already asleep. 285 */ 286 splz(); 287 oldpri = td->td_pri & TDPRI_MASK; 288 lwkt_setpri_self(safepri); 289 lwkt_switch(); 290 lwkt_setpri_self(oldpri); 291 return (0); 292 } 293 gd = td->td_gd; 294 KKASSERT(td != &gd->gd_idlethread); /* you must be kidding! */ 295 crit_enter_quick(td); 296 KASSERT(ident != NULL, ("tsleep: no ident")); 297 KASSERT(p == NULL || p->p_stat == SRUN, ("tsleep %p %s %d", 298 ident, wmesg, p->p_stat)); 299 300 td->td_wchan = ident; 301 td->td_wmesg = wmesg; 302 td->td_wdomain = flags & PDOMAIN_MASK; 303 if (p) { 304 if (flags & PNORESCHED) 305 td->td_flags |= TDF_NORESCHED; 306 p->p_usched->release_curproc(&p->p_lwp); 307 p->p_slptime = 0; 308 } 309 310 /* 311 * note: all of this occurs on the current cpu, including any 312 * callout-based wakeups, so a critical section is a sufficient 313 * interlock. 314 */ 315 lwkt_deschedule_self(td); 316 TAILQ_INSERT_TAIL(&gd->gd_tsleep_hash[id], td, td_threadq); 317 atomic_set_int(&slpque_cpumasks[id], gd->gd_cpumask); 318 if (timo) { 319 callout_init(&thandle); 320 callout_reset(&thandle, timo, endtsleep, td); 321 } 322 /* 323 * We put ourselves on the sleep queue and start our timeout 324 * before calling CURSIG, as we could stop there, and a wakeup 325 * or a SIGCONT (or both) could occur while we were stopped. 326 * A SIGCONT would cause us to be marked as SSLEEP 327 * without resuming us, thus we must be ready for sleep 328 * when CURSIG is called. If the wakeup happens while we're 329 * stopped, td->td_wchan will be 0 upon return from CURSIG. 330 */ 331 if (p) { 332 if (catch) { 333 p->p_flag |= P_SINTR; 334 if ((sig = CURSIG(p))) { 335 if (td->td_wchan) { 336 unsleep(td); 337 lwkt_schedule_self(td); 338 } 339 p->p_stat = SRUN; 340 goto resume; 341 } 342 if (td->td_wchan == NULL) { 343 catch = 0; 344 goto resume; 345 } 346 } else { 347 sig = 0; 348 } 349 350 /* 351 * If we are not the current process we have to remove ourself 352 * from the run queue. 353 */ 354 KASSERT(p->p_stat == SRUN, ("PSTAT NOT SRUN %d %d", p->p_pid, p->p_stat)); 355 /* 356 * If this is the current 'user' process schedule another one. 357 */ 358 clrrunnable(p, SSLEEP); 359 p->p_stats->p_ru.ru_nvcsw++; 360 mi_switch(p); 361 KASSERT(p->p_stat == SRUN, ("tsleep: stat not srun")); 362 } else { 363 lwkt_switch(); 364 } 365 /* 366 * Make sure we haven't switched cpus while we were asleep. It's 367 * not supposed to happen. 368 */ 369 KKASSERT(gd == td->td_gd); 370 resume: 371 if (p) 372 p->p_flag &= ~P_SINTR; 373 crit_exit_quick(td); 374 td->td_flags &= ~TDF_NORESCHED; 375 if (td->td_flags & TDF_TIMEOUT) { 376 td->td_flags &= ~TDF_TIMEOUT; 377 if (sig == 0) 378 return (EWOULDBLOCK); 379 } else if (timo) { 380 callout_stop(&thandle); 381 } else if (td->td_wmesg) { 382 /* 383 * This can happen if a thread is woken up directly. Clear 384 * wmesg to avoid debugging confusion. 385 */ 386 td->td_wmesg = NULL; 387 } 388 /* inline of iscaught() */ 389 if (p) { 390 if (catch && (sig != 0 || (sig = CURSIG(p)))) { 391 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig)) 392 return (EINTR); 393 return (ERESTART); 394 } 395 } 396 return (0); 397 } 398 399 /* 400 * Implement the timeout for tsleep. We interlock against 401 * wchan when setting TDF_TIMEOUT. For processes we remove 402 * the sleep if the process is stopped rather then sleeping, 403 * so it remains stopped. 404 * 405 * This type of callout timeout had better be scheduled on the same 406 * cpu the process is sleeping on. 407 */ 408 static void 409 endtsleep(void *arg) 410 { 411 thread_t td = arg; 412 struct proc *p; 413 414 crit_enter(); 415 if (td->td_wchan) { 416 td->td_flags |= TDF_TIMEOUT; 417 if ((p = td->td_proc) != NULL) { 418 if (p->p_stat == SSLEEP) 419 setrunnable(p); 420 else 421 unsleep(td); 422 } else { 423 unsleep(td); 424 lwkt_schedule(td); 425 } 426 } 427 crit_exit(); 428 } 429 430 /* 431 * Remove a process from its wait queue 432 * 433 * XXX not MP safe until called only on the cpu holding the sleeping 434 * process. 435 */ 436 void 437 unsleep(struct thread *td) 438 { 439 int id; 440 441 crit_enter(); 442 id = LOOKUP(td->td_wchan); 443 if (td->td_wchan) { 444 TAILQ_REMOVE(&td->td_gd->gd_tsleep_hash[id], td, td_threadq); 445 if (TAILQ_FIRST(&td->td_gd->gd_tsleep_hash[id]) == NULL) 446 atomic_clear_int(&slpque_cpumasks[id], td->td_gd->gd_cpumask); 447 td->td_wchan = NULL; 448 } 449 crit_exit(); 450 } 451 452 /* 453 * Make all processes sleeping on the specified identifier runnable. 454 * count may be zero or one only. 455 * 456 * The domain encodes the sleep/wakeup domain AND the first cpu to check 457 * (which is always the current cpu). As we iterate across cpus 458 */ 459 static void 460 _wakeup(void *ident, int domain) 461 { 462 struct tslpque *qp; 463 struct thread *td; 464 struct thread *ntd; 465 globaldata_t gd; 466 struct proc *p; 467 #if 0 468 #ifdef SMP 469 cpumask_t mask; 470 cpumask_t tmask; 471 int startcpu; 472 int nextcpu; 473 #endif 474 #endif 475 int id; 476 477 crit_enter(); 478 gd = mycpu; 479 id = LOOKUP(ident); 480 qp = &gd->gd_tsleep_hash[id]; 481 restart: 482 for (td = TAILQ_FIRST(qp); td != NULL; td = ntd) { 483 ntd = TAILQ_NEXT(td, td_threadq); 484 if (td->td_wchan == ident && 485 td->td_wdomain == (domain & PDOMAIN_MASK) 486 ) { 487 TAILQ_REMOVE(qp, td, td_threadq); 488 if (TAILQ_FIRST(qp) == NULL) { 489 atomic_clear_int(&slpque_cpumasks[id], 490 gd->gd_cpumask); 491 } 492 td->td_wchan = NULL; 493 if ((p = td->td_proc) != NULL && p->p_stat == SSLEEP) { 494 p->p_stat = SRUN; 495 if (p->p_flag & P_INMEM) { 496 /* 497 * LWKT scheduled now, there is no 498 * userland runq interaction until 499 * the thread tries to return to user 500 * mode. We do NOT call setrunqueue(). 501 */ 502 lwkt_schedule(td); 503 } else { 504 p->p_flag |= P_SWAPINREQ; 505 wakeup((caddr_t)&proc0); 506 } 507 /* END INLINE EXPANSION */ 508 } else if (p == NULL) { 509 lwkt_schedule(td); 510 } 511 if (domain & PWAKEUP_ONE) 512 goto done; 513 goto restart; 514 } 515 } 516 517 #if 0 518 #ifdef SMP 519 /* 520 * We finished checking the current cpu but there still may be 521 * more work to do. Either wakeup_one was requested and no matching 522 * thread was found, or a normal wakeup was requested and we have 523 * to continue checking cpus. 524 * 525 * The cpu that started the wakeup sequence is encoded in the domain. 526 * We use this information to determine which cpus still need to be 527 * checked, locate a candidate cpu, and chain the wakeup 528 * asynchronously with an IPI message. 529 * 530 * It should be noted that this scheme is actually less expensive then 531 * the old scheme when waking up multiple threads, since we send 532 * only one IPI message per target candidate which may then schedule 533 * multiple threads. Before we could have wound up sending an IPI 534 * message for each thread on the target cpu (!= current cpu) that 535 * needed to be woken up. 536 * 537 * NOTE: Wakeups occuring on remote cpus are asynchronous. This 538 * should be ok since we are passing idents in the IPI rather then 539 * thread pointers. 540 */ 541 if ((mask = slpque_cpumasks[id]) != 0) { 542 /* 543 * Look for a cpu that might have work to do. Mask out cpus 544 * which have already been processed. 545 * 546 * 31xxxxxxxxxxxxxxxxxxxxxxxxxxxxx0 547 * ^ ^ ^ 548 * start currentcpu start 549 * case2 case1 550 * * * * 551 * 11111111111111110000000000000111 case1 552 * 00000000111111110000000000000000 case2 553 * 554 * case1: We started at start_case1 and processed through 555 * to the current cpu. We have to check any bits 556 * after the current cpu, then check bits before 557 * the starting cpu. 558 * 559 * case2: We have already checked all the bits from 560 * start_case2 to the end, and from 0 to the current 561 * cpu. We just have the bits from the current cpu 562 * to start_case2 left to check. 563 */ 564 startcpu = PWAKEUP_DECODE(domain); 565 if (gd->gd_cpuid >= startcpu) { 566 /* 567 * CASE1 568 */ 569 tmask = mask & ~((gd->gd_cpumask << 1) - 1); 570 if (mask & tmask) { 571 nextcpu = bsfl(mask & tmask); 572 lwkt_send_ipiq2(globaldata_find(nextcpu), 573 _wakeup, ident, domain); 574 } else { 575 tmask = (1 << startcpu) - 1; 576 if (mask & tmask) { 577 nextcpu = bsfl(mask & tmask); 578 lwkt_send_ipiq2( 579 globaldata_find(nextcpu), 580 _wakeup, ident, domain); 581 } 582 } 583 } else { 584 /* 585 * CASE2 586 */ 587 tmask = ~((gd->gd_cpumask << 1) - 1) & 588 ((1 << startcpu) - 1); 589 if (mask & tmask) { 590 nextcpu = bsfl(mask & tmask); 591 lwkt_send_ipiq2(globaldata_find(nextcpu), 592 _wakeup, ident, domain); 593 } 594 } 595 } 596 #endif 597 #endif 598 done: 599 crit_exit(); 600 } 601 602 void 603 wakeup(void *ident) 604 { 605 _wakeup(ident, PWAKEUP_ENCODE(0, mycpu->gd_cpuid)); 606 } 607 608 void 609 wakeup_one(void *ident) 610 { 611 /* XXX potentially round-robin the first responding cpu */ 612 _wakeup(ident, PWAKEUP_ENCODE(0, mycpu->gd_cpuid) | PWAKEUP_ONE); 613 } 614 615 void 616 wakeup_domain(void *ident, int domain) 617 { 618 _wakeup(ident, PWAKEUP_ENCODE(domain, mycpu->gd_cpuid)); 619 } 620 621 void 622 wakeup_domain_one(void *ident, int domain) 623 { 624 /* XXX potentially round-robin the first responding cpu */ 625 _wakeup(ident, PWAKEUP_ENCODE(domain, mycpu->gd_cpuid) | PWAKEUP_ONE); 626 } 627 628 /* 629 * The machine independent parts of mi_switch(). 630 * 631 * 'p' must be the current process. 632 */ 633 void 634 mi_switch(struct proc *p) 635 { 636 thread_t td = p->p_thread; 637 struct rlimit *rlim; 638 u_int64_t ttime; 639 640 KKASSERT(td == mycpu->gd_curthread); 641 642 crit_enter_quick(td); 643 644 /* 645 * Check if the process exceeds its cpu resource allocation. 646 * If over max, kill it. Time spent in interrupts is not 647 * included. YYY 64 bit match is expensive. Ick. 648 * 649 * XXX move to the once-a-second process scan 650 */ 651 ttime = td->td_sticks + td->td_uticks; 652 if (p->p_stat != SZOMB && p->p_limit->p_cpulimit != RLIM_INFINITY && 653 ttime > p->p_limit->p_cpulimit) { 654 rlim = &p->p_rlimit[RLIMIT_CPU]; 655 if (ttime / (rlim_t)1000000 >= rlim->rlim_max) { 656 killproc(p, "exceeded maximum CPU limit"); 657 } else { 658 psignal(p, SIGXCPU); 659 if (rlim->rlim_cur < rlim->rlim_max) { 660 /* XXX: we should make a private copy */ 661 rlim->rlim_cur += 5; 662 } 663 } 664 } 665 666 /* 667 * If we are in a SSTOPped state we deschedule ourselves. 668 * YYY this needs to be cleaned up, remember that LWKTs stay on 669 * their run queue which works differently then the user scheduler 670 * which removes the process from the runq when it runs it. 671 */ 672 mycpu->gd_cnt.v_swtch++; 673 if (p->p_stat == SSTOP) 674 lwkt_deschedule_self(td); 675 lwkt_switch(); 676 crit_exit_quick(td); 677 } 678 679 /* 680 * Change process state to be runnable, placing it on the run queue if it 681 * is in memory, and awakening the swapper if it isn't in memory. 682 * 683 * This operation MUST OCCUR on the cpu that the thread is sleeping on. 684 */ 685 void 686 setrunnable(struct proc *p) 687 { 688 crit_enter(); 689 690 switch (p->p_stat) { 691 case 0: 692 case SRUN: 693 case SZOMB: 694 default: 695 panic("setrunnable"); 696 case SSTOP: 697 case SSLEEP: 698 unsleep(p->p_thread); /* e.g. when sending signals */ 699 break; 700 701 case SIDL: 702 break; 703 } 704 p->p_stat = SRUN; 705 706 /* 707 * The process is controlled by LWKT at this point, we do not mess 708 * around with the userland scheduler until the thread tries to 709 * return to user mode. We do not clear p_slptime or call 710 * setrunqueue(). 711 */ 712 if (p->p_flag & P_INMEM) { 713 lwkt_schedule(p->p_thread); 714 } else { 715 p->p_flag |= P_SWAPINREQ; 716 wakeup((caddr_t)&proc0); 717 } 718 crit_exit(); 719 } 720 721 /* 722 * Yield / synchronous reschedule. This is a bit tricky because the trap 723 * code might have set a lazy release on the switch function. Setting 724 * P_PASSIVE_ACQ will ensure that the lazy release executes when we call 725 * switch, and that we are given a greater chance of affinity with our 726 * current cpu. 727 * 728 * We call lwkt_setpri_self() to rotate our thread to the end of the lwkt 729 * run queue. lwkt_switch() will also execute any assigned passive release 730 * (which usually calls release_curproc()), allowing a same/higher priority 731 * process to be designated as the current process. 732 * 733 * While it is possible for a lower priority process to be designated, 734 * it's call to lwkt_maybe_switch() in acquire_curproc() will likely 735 * round-robin back to us and we will be able to re-acquire the current 736 * process designation. 737 */ 738 void 739 uio_yield(void) 740 { 741 struct thread *td = curthread; 742 struct proc *p = td->td_proc; 743 744 lwkt_setpri_self(td->td_pri & TDPRI_MASK); 745 if (p) { 746 p->p_flag |= P_PASSIVE_ACQ; 747 lwkt_switch(); 748 p->p_flag &= ~P_PASSIVE_ACQ; 749 } else { 750 lwkt_switch(); 751 } 752 } 753 754 /* 755 * Change the process state to NOT be runnable, removing it from the run 756 * queue. 757 */ 758 void 759 clrrunnable(struct proc *p, int stat) 760 { 761 crit_enter_quick(p->p_thread); 762 if (p->p_stat == SRUN && (p->p_flag & P_ONRUNQ)) 763 p->p_usched->remrunqueue(&p->p_lwp); 764 p->p_stat = stat; 765 crit_exit_quick(p->p_thread); 766 } 767 768 /* 769 * Compute a tenex style load average of a quantity on 770 * 1, 5 and 15 minute intervals. 771 */ 772 static void 773 loadav(void *arg) 774 { 775 int i, nrun; 776 struct loadavg *avg; 777 struct proc *p; 778 thread_t td; 779 780 avg = &averunnable; 781 nrun = 0; 782 FOREACH_PROC_IN_SYSTEM(p) { 783 switch (p->p_stat) { 784 case SRUN: 785 if ((td = p->p_thread) == NULL) 786 break; 787 if (td->td_flags & TDF_BLOCKED) 788 break; 789 /* fall through */ 790 case SIDL: 791 nrun++; 792 break; 793 default: 794 break; 795 } 796 } 797 for (i = 0; i < 3; i++) 798 avg->ldavg[i] = (cexp[i] * avg->ldavg[i] + 799 nrun * FSCALE * (FSCALE - cexp[i])) >> FSHIFT; 800 801 /* 802 * Schedule the next update to occur after 5 seconds, but add a 803 * random variation to avoid synchronisation with processes that 804 * run at regular intervals. 805 */ 806 callout_reset(&loadav_callout, hz * 4 + (int)(random() % (hz * 2 + 1)), 807 loadav, NULL); 808 } 809 810 /* ARGSUSED */ 811 static void 812 sched_setup(void *dummy) 813 { 814 callout_init(&loadav_callout); 815 callout_init(&schedcpu_callout); 816 817 /* Kick off timeout driven events by calling first time. */ 818 schedcpu(NULL); 819 loadav(NULL); 820 } 821 822