1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1982, 1986, 1990, 1991, 1993 5 * The Regents of the University of California. All rights reserved. 6 * (c) UNIX System Laboratories, Inc. 7 * All or some portions of this file are derived from material licensed 8 * to the University of California by American Telephone and Telegraph 9 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 10 * the permission of UNIX System Laboratories, Inc. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 */ 36 37 #include <sys/cdefs.h> 38 __FBSDID("$FreeBSD$"); 39 40 #include "opt_hwpmc_hooks.h" 41 #include "opt_sched.h" 42 43 #include <sys/param.h> 44 #include <sys/systm.h> 45 #include <sys/cpuset.h> 46 #include <sys/kernel.h> 47 #include <sys/ktr.h> 48 #include <sys/lock.h> 49 #include <sys/kthread.h> 50 #include <sys/mutex.h> 51 #include <sys/proc.h> 52 #include <sys/resourcevar.h> 53 #include <sys/sched.h> 54 #include <sys/sdt.h> 55 #include <sys/smp.h> 56 #include <sys/sysctl.h> 57 #include <sys/sx.h> 58 #include <sys/turnstile.h> 59 #include <sys/umtx.h> 60 #include <machine/pcb.h> 61 #include <machine/smp.h> 62 63 #ifdef HWPMC_HOOKS 64 #include <sys/pmckern.h> 65 #endif 66 67 #ifdef KDTRACE_HOOKS 68 #include <sys/dtrace_bsd.h> 69 int __read_mostly dtrace_vtime_active; 70 dtrace_vtime_switch_func_t dtrace_vtime_switch_func; 71 #endif 72 73 /* 74 * INVERSE_ESTCPU_WEIGHT is only suitable for statclock() frequencies in 75 * the range 100-256 Hz (approximately). 76 */ 77 #define ESTCPULIM(e) \ 78 min((e), INVERSE_ESTCPU_WEIGHT * (NICE_WEIGHT * (PRIO_MAX - PRIO_MIN) - \ 79 RQ_PPQ) + INVERSE_ESTCPU_WEIGHT - 1) 80 #ifdef SMP 81 #define INVERSE_ESTCPU_WEIGHT (8 * smp_cpus) 82 #else 83 #define INVERSE_ESTCPU_WEIGHT 8 /* 1 / (priorities per estcpu level). */ 84 #endif 85 #define NICE_WEIGHT 1 /* Priorities per nice level. */ 86 87 #define TS_NAME_LEN (MAXCOMLEN + sizeof(" td ") + sizeof(__XSTRING(UINT_MAX))) 88 89 /* 90 * The schedulable entity that runs a context. 91 * This is an extension to the thread structure and is tailored to 92 * the requirements of this scheduler. 93 * All fields are protected by the scheduler lock. 94 */ 95 struct td_sched { 96 fixpt_t ts_pctcpu; /* %cpu during p_swtime. */ 97 u_int ts_estcpu; /* Estimated cpu utilization. */ 98 int ts_cpticks; /* Ticks of cpu time. */ 99 int ts_slptime; /* Seconds !RUNNING. */ 100 int ts_slice; /* Remaining part of time slice. */ 101 int ts_flags; 102 struct runq *ts_runq; /* runq the thread is currently on */ 103 #ifdef KTR 104 char ts_name[TS_NAME_LEN]; 105 #endif 106 }; 107 108 /* flags kept in td_flags */ 109 #define TDF_DIDRUN TDF_SCHED0 /* thread actually ran. */ 110 #define TDF_BOUND TDF_SCHED1 /* Bound to one CPU. */ 111 #define TDF_SLICEEND TDF_SCHED2 /* Thread time slice is over. */ 112 113 /* flags kept in ts_flags */ 114 #define TSF_AFFINITY 0x0001 /* Has a non-"full" CPU set. */ 115 116 #define SKE_RUNQ_PCPU(ts) \ 117 ((ts)->ts_runq != 0 && (ts)->ts_runq != &runq) 118 119 #define THREAD_CAN_SCHED(td, cpu) \ 120 CPU_ISSET((cpu), &(td)->td_cpuset->cs_mask) 121 122 _Static_assert(sizeof(struct thread) + sizeof(struct td_sched) <= 123 sizeof(struct thread0_storage), 124 "increase struct thread0_storage.t0st_sched size"); 125 126 static struct mtx sched_lock; 127 128 static int realstathz = 127; /* stathz is sometimes 0 and run off of hz. */ 129 static int sched_tdcnt; /* Total runnable threads in the system. */ 130 static int sched_slice = 12; /* Thread run time before rescheduling. */ 131 132 static void setup_runqs(void); 133 static void schedcpu(void); 134 static void schedcpu_thread(void); 135 static void sched_priority(struct thread *td, u_char prio); 136 static void sched_setup(void *dummy); 137 static void maybe_resched(struct thread *td); 138 static void updatepri(struct thread *td); 139 static void resetpriority(struct thread *td); 140 static void resetpriority_thread(struct thread *td); 141 #ifdef SMP 142 static int sched_pickcpu(struct thread *td); 143 static int forward_wakeup(int cpunum); 144 static void kick_other_cpu(int pri, int cpuid); 145 #endif 146 147 static struct kproc_desc sched_kp = { 148 "schedcpu", 149 schedcpu_thread, 150 NULL 151 }; 152 SYSINIT(schedcpu, SI_SUB_LAST, SI_ORDER_FIRST, kproc_start, 153 &sched_kp); 154 SYSINIT(sched_setup, SI_SUB_RUN_QUEUE, SI_ORDER_FIRST, sched_setup, NULL); 155 156 static void sched_initticks(void *dummy); 157 SYSINIT(sched_initticks, SI_SUB_CLOCKS, SI_ORDER_THIRD, sched_initticks, 158 NULL); 159 160 /* 161 * Global run queue. 162 */ 163 static struct runq runq; 164 165 #ifdef SMP 166 /* 167 * Per-CPU run queues 168 */ 169 static struct runq runq_pcpu[MAXCPU]; 170 long runq_length[MAXCPU]; 171 172 static cpuset_t idle_cpus_mask; 173 #endif 174 175 struct pcpuidlestat { 176 u_int idlecalls; 177 u_int oldidlecalls; 178 }; 179 DPCPU_DEFINE_STATIC(struct pcpuidlestat, idlestat); 180 181 static void 182 setup_runqs(void) 183 { 184 #ifdef SMP 185 int i; 186 187 for (i = 0; i < MAXCPU; ++i) 188 runq_init(&runq_pcpu[i]); 189 #endif 190 191 runq_init(&runq); 192 } 193 194 static int 195 sysctl_kern_quantum(SYSCTL_HANDLER_ARGS) 196 { 197 int error, new_val, period; 198 199 period = 1000000 / realstathz; 200 new_val = period * sched_slice; 201 error = sysctl_handle_int(oidp, &new_val, 0, req); 202 if (error != 0 || req->newptr == NULL) 203 return (error); 204 if (new_val <= 0) 205 return (EINVAL); 206 sched_slice = imax(1, (new_val + period / 2) / period); 207 hogticks = imax(1, (2 * hz * sched_slice + realstathz / 2) / 208 realstathz); 209 return (0); 210 } 211 212 SYSCTL_NODE(_kern, OID_AUTO, sched, CTLFLAG_RD, 0, "Scheduler"); 213 214 SYSCTL_STRING(_kern_sched, OID_AUTO, name, CTLFLAG_RD, "4BSD", 0, 215 "Scheduler name"); 216 SYSCTL_PROC(_kern_sched, OID_AUTO, quantum, CTLTYPE_INT | CTLFLAG_RW, 217 NULL, 0, sysctl_kern_quantum, "I", 218 "Quantum for timeshare threads in microseconds"); 219 SYSCTL_INT(_kern_sched, OID_AUTO, slice, CTLFLAG_RW, &sched_slice, 0, 220 "Quantum for timeshare threads in stathz ticks"); 221 #ifdef SMP 222 /* Enable forwarding of wakeups to all other cpus */ 223 static SYSCTL_NODE(_kern_sched, OID_AUTO, ipiwakeup, CTLFLAG_RD, NULL, 224 "Kernel SMP"); 225 226 static int runq_fuzz = 1; 227 SYSCTL_INT(_kern_sched, OID_AUTO, runq_fuzz, CTLFLAG_RW, &runq_fuzz, 0, ""); 228 229 static int forward_wakeup_enabled = 1; 230 SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, enabled, CTLFLAG_RW, 231 &forward_wakeup_enabled, 0, 232 "Forwarding of wakeup to idle CPUs"); 233 234 static int forward_wakeups_requested = 0; 235 SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, requested, CTLFLAG_RD, 236 &forward_wakeups_requested, 0, 237 "Requests for Forwarding of wakeup to idle CPUs"); 238 239 static int forward_wakeups_delivered = 0; 240 SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, delivered, CTLFLAG_RD, 241 &forward_wakeups_delivered, 0, 242 "Completed Forwarding of wakeup to idle CPUs"); 243 244 static int forward_wakeup_use_mask = 1; 245 SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, usemask, CTLFLAG_RW, 246 &forward_wakeup_use_mask, 0, 247 "Use the mask of idle cpus"); 248 249 static int forward_wakeup_use_loop = 0; 250 SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, useloop, CTLFLAG_RW, 251 &forward_wakeup_use_loop, 0, 252 "Use a loop to find idle cpus"); 253 254 #endif 255 #if 0 256 static int sched_followon = 0; 257 SYSCTL_INT(_kern_sched, OID_AUTO, followon, CTLFLAG_RW, 258 &sched_followon, 0, 259 "allow threads to share a quantum"); 260 #endif 261 262 SDT_PROVIDER_DEFINE(sched); 263 264 SDT_PROBE_DEFINE3(sched, , , change__pri, "struct thread *", 265 "struct proc *", "uint8_t"); 266 SDT_PROBE_DEFINE3(sched, , , dequeue, "struct thread *", 267 "struct proc *", "void *"); 268 SDT_PROBE_DEFINE4(sched, , , enqueue, "struct thread *", 269 "struct proc *", "void *", "int"); 270 SDT_PROBE_DEFINE4(sched, , , lend__pri, "struct thread *", 271 "struct proc *", "uint8_t", "struct thread *"); 272 SDT_PROBE_DEFINE2(sched, , , load__change, "int", "int"); 273 SDT_PROBE_DEFINE2(sched, , , off__cpu, "struct thread *", 274 "struct proc *"); 275 SDT_PROBE_DEFINE(sched, , , on__cpu); 276 SDT_PROBE_DEFINE(sched, , , remain__cpu); 277 SDT_PROBE_DEFINE2(sched, , , surrender, "struct thread *", 278 "struct proc *"); 279 280 static __inline void 281 sched_load_add(void) 282 { 283 284 sched_tdcnt++; 285 KTR_COUNTER0(KTR_SCHED, "load", "global load", sched_tdcnt); 286 SDT_PROBE2(sched, , , load__change, NOCPU, sched_tdcnt); 287 } 288 289 static __inline void 290 sched_load_rem(void) 291 { 292 293 sched_tdcnt--; 294 KTR_COUNTER0(KTR_SCHED, "load", "global load", sched_tdcnt); 295 SDT_PROBE2(sched, , , load__change, NOCPU, sched_tdcnt); 296 } 297 /* 298 * Arrange to reschedule if necessary, taking the priorities and 299 * schedulers into account. 300 */ 301 static void 302 maybe_resched(struct thread *td) 303 { 304 305 THREAD_LOCK_ASSERT(td, MA_OWNED); 306 if (td->td_priority < curthread->td_priority) 307 curthread->td_flags |= TDF_NEEDRESCHED; 308 } 309 310 /* 311 * This function is called when a thread is about to be put on run queue 312 * because it has been made runnable or its priority has been adjusted. It 313 * determines if the new thread should preempt the current thread. If so, 314 * it sets td_owepreempt to request a preemption. 315 */ 316 int 317 maybe_preempt(struct thread *td) 318 { 319 #ifdef PREEMPTION 320 struct thread *ctd; 321 int cpri, pri; 322 323 /* 324 * The new thread should not preempt the current thread if any of the 325 * following conditions are true: 326 * 327 * - The kernel is in the throes of crashing (panicstr). 328 * - The current thread has a higher (numerically lower) or 329 * equivalent priority. Note that this prevents curthread from 330 * trying to preempt to itself. 331 * - The current thread has an inhibitor set or is in the process of 332 * exiting. In this case, the current thread is about to switch 333 * out anyways, so there's no point in preempting. If we did, 334 * the current thread would not be properly resumed as well, so 335 * just avoid that whole landmine. 336 * - If the new thread's priority is not a realtime priority and 337 * the current thread's priority is not an idle priority and 338 * FULL_PREEMPTION is disabled. 339 * 340 * If all of these conditions are false, but the current thread is in 341 * a nested critical section, then we have to defer the preemption 342 * until we exit the critical section. Otherwise, switch immediately 343 * to the new thread. 344 */ 345 ctd = curthread; 346 THREAD_LOCK_ASSERT(td, MA_OWNED); 347 KASSERT((td->td_inhibitors == 0), 348 ("maybe_preempt: trying to run inhibited thread")); 349 pri = td->td_priority; 350 cpri = ctd->td_priority; 351 if (KERNEL_PANICKED() || pri >= cpri /* || dumping */ || 352 TD_IS_INHIBITED(ctd)) 353 return (0); 354 #ifndef FULL_PREEMPTION 355 if (pri > PRI_MAX_ITHD && cpri < PRI_MIN_IDLE) 356 return (0); 357 #endif 358 359 CTR0(KTR_PROC, "maybe_preempt: scheduling preemption"); 360 ctd->td_owepreempt = 1; 361 return (1); 362 #else 363 return (0); 364 #endif 365 } 366 367 /* 368 * Constants for digital decay and forget: 369 * 90% of (ts_estcpu) usage in 5 * loadav time 370 * 95% of (ts_pctcpu) usage in 60 seconds (load insensitive) 371 * Note that, as ps(1) mentions, this can let percentages 372 * total over 100% (I've seen 137.9% for 3 processes). 373 * 374 * Note that schedclock() updates ts_estcpu and p_cpticks asynchronously. 375 * 376 * We wish to decay away 90% of ts_estcpu in (5 * loadavg) seconds. 377 * That is, the system wants to compute a value of decay such 378 * that the following for loop: 379 * for (i = 0; i < (5 * loadavg); i++) 380 * ts_estcpu *= decay; 381 * will compute 382 * ts_estcpu *= 0.1; 383 * for all values of loadavg: 384 * 385 * Mathematically this loop can be expressed by saying: 386 * decay ** (5 * loadavg) ~= .1 387 * 388 * The system computes decay as: 389 * decay = (2 * loadavg) / (2 * loadavg + 1) 390 * 391 * We wish to prove that the system's computation of decay 392 * will always fulfill the equation: 393 * decay ** (5 * loadavg) ~= .1 394 * 395 * If we compute b as: 396 * b = 2 * loadavg 397 * then 398 * decay = b / (b + 1) 399 * 400 * We now need to prove two things: 401 * 1) Given factor ** (5 * loadavg) ~= .1, prove factor == b/(b+1) 402 * 2) Given b/(b+1) ** power ~= .1, prove power == (5 * loadavg) 403 * 404 * Facts: 405 * For x close to zero, exp(x) =~ 1 + x, since 406 * exp(x) = 0! + x**1/1! + x**2/2! + ... . 407 * therefore exp(-1/b) =~ 1 - (1/b) = (b-1)/b. 408 * For x close to zero, ln(1+x) =~ x, since 409 * ln(1+x) = x - x**2/2 + x**3/3 - ... -1 < x < 1 410 * therefore ln(b/(b+1)) = ln(1 - 1/(b+1)) =~ -1/(b+1). 411 * ln(.1) =~ -2.30 412 * 413 * Proof of (1): 414 * Solve (factor)**(power) =~ .1 given power (5*loadav): 415 * solving for factor, 416 * ln(factor) =~ (-2.30/5*loadav), or 417 * factor =~ exp(-1/((5/2.30)*loadav)) =~ exp(-1/(2*loadav)) = 418 * exp(-1/b) =~ (b-1)/b =~ b/(b+1). QED 419 * 420 * Proof of (2): 421 * Solve (factor)**(power) =~ .1 given factor == (b/(b+1)): 422 * solving for power, 423 * power*ln(b/(b+1)) =~ -2.30, or 424 * power =~ 2.3 * (b + 1) = 4.6*loadav + 2.3 =~ 5*loadav. QED 425 * 426 * Actual power values for the implemented algorithm are as follows: 427 * loadav: 1 2 3 4 428 * power: 5.68 10.32 14.94 19.55 429 */ 430 431 /* calculations for digital decay to forget 90% of usage in 5*loadav sec */ 432 #define loadfactor(loadav) (2 * (loadav)) 433 #define decay_cpu(loadfac, cpu) (((loadfac) * (cpu)) / ((loadfac) + FSCALE)) 434 435 /* decay 95% of `ts_pctcpu' in 60 seconds; see CCPU_SHIFT before changing */ 436 static fixpt_t ccpu = 0.95122942450071400909 * FSCALE; /* exp(-1/20) */ 437 SYSCTL_UINT(_kern, OID_AUTO, ccpu, CTLFLAG_RD, &ccpu, 0, ""); 438 439 /* 440 * If `ccpu' is not equal to `exp(-1/20)' and you still want to use the 441 * faster/more-accurate formula, you'll have to estimate CCPU_SHIFT below 442 * and possibly adjust FSHIFT in "param.h" so that (FSHIFT >= CCPU_SHIFT). 443 * 444 * To estimate CCPU_SHIFT for exp(-1/20), the following formula was used: 445 * 1 - exp(-1/20) ~= 0.0487 ~= 0.0488 == 1 (fixed pt, *11* bits). 446 * 447 * If you don't want to bother with the faster/more-accurate formula, you 448 * can set CCPU_SHIFT to (FSHIFT + 1) which will use a slower/less-accurate 449 * (more general) method of calculating the %age of CPU used by a process. 450 */ 451 #define CCPU_SHIFT 11 452 453 /* 454 * Recompute process priorities, every hz ticks. 455 * MP-safe, called without the Giant mutex. 456 */ 457 /* ARGSUSED */ 458 static void 459 schedcpu(void) 460 { 461 fixpt_t loadfac = loadfactor(averunnable.ldavg[0]); 462 struct thread *td; 463 struct proc *p; 464 struct td_sched *ts; 465 int awake; 466 467 sx_slock(&allproc_lock); 468 FOREACH_PROC_IN_SYSTEM(p) { 469 PROC_LOCK(p); 470 if (p->p_state == PRS_NEW) { 471 PROC_UNLOCK(p); 472 continue; 473 } 474 FOREACH_THREAD_IN_PROC(p, td) { 475 awake = 0; 476 ts = td_get_sched(td); 477 thread_lock(td); 478 /* 479 * Increment sleep time (if sleeping). We 480 * ignore overflow, as above. 481 */ 482 /* 483 * The td_sched slptimes are not touched in wakeup 484 * because the thread may not HAVE everything in 485 * memory? XXX I think this is out of date. 486 */ 487 if (TD_ON_RUNQ(td)) { 488 awake = 1; 489 td->td_flags &= ~TDF_DIDRUN; 490 } else if (TD_IS_RUNNING(td)) { 491 awake = 1; 492 /* Do not clear TDF_DIDRUN */ 493 } else if (td->td_flags & TDF_DIDRUN) { 494 awake = 1; 495 td->td_flags &= ~TDF_DIDRUN; 496 } 497 498 /* 499 * ts_pctcpu is only for ps and ttyinfo(). 500 */ 501 ts->ts_pctcpu = (ts->ts_pctcpu * ccpu) >> FSHIFT; 502 /* 503 * If the td_sched has been idle the entire second, 504 * stop recalculating its priority until 505 * it wakes up. 506 */ 507 if (ts->ts_cpticks != 0) { 508 #if (FSHIFT >= CCPU_SHIFT) 509 ts->ts_pctcpu += (realstathz == 100) 510 ? ((fixpt_t) ts->ts_cpticks) << 511 (FSHIFT - CCPU_SHIFT) : 512 100 * (((fixpt_t) ts->ts_cpticks) 513 << (FSHIFT - CCPU_SHIFT)) / realstathz; 514 #else 515 ts->ts_pctcpu += ((FSCALE - ccpu) * 516 (ts->ts_cpticks * 517 FSCALE / realstathz)) >> FSHIFT; 518 #endif 519 ts->ts_cpticks = 0; 520 } 521 /* 522 * If there are ANY running threads in this process, 523 * then don't count it as sleeping. 524 * XXX: this is broken. 525 */ 526 if (awake) { 527 if (ts->ts_slptime > 1) { 528 /* 529 * In an ideal world, this should not 530 * happen, because whoever woke us 531 * up from the long sleep should have 532 * unwound the slptime and reset our 533 * priority before we run at the stale 534 * priority. Should KASSERT at some 535 * point when all the cases are fixed. 536 */ 537 updatepri(td); 538 } 539 ts->ts_slptime = 0; 540 } else 541 ts->ts_slptime++; 542 if (ts->ts_slptime > 1) { 543 thread_unlock(td); 544 continue; 545 } 546 ts->ts_estcpu = decay_cpu(loadfac, ts->ts_estcpu); 547 resetpriority(td); 548 resetpriority_thread(td); 549 thread_unlock(td); 550 } 551 PROC_UNLOCK(p); 552 } 553 sx_sunlock(&allproc_lock); 554 } 555 556 /* 557 * Main loop for a kthread that executes schedcpu once a second. 558 */ 559 static void 560 schedcpu_thread(void) 561 { 562 563 for (;;) { 564 schedcpu(); 565 pause("-", hz); 566 } 567 } 568 569 /* 570 * Recalculate the priority of a process after it has slept for a while. 571 * For all load averages >= 1 and max ts_estcpu of 255, sleeping for at 572 * least six times the loadfactor will decay ts_estcpu to zero. 573 */ 574 static void 575 updatepri(struct thread *td) 576 { 577 struct td_sched *ts; 578 fixpt_t loadfac; 579 unsigned int newcpu; 580 581 ts = td_get_sched(td); 582 loadfac = loadfactor(averunnable.ldavg[0]); 583 if (ts->ts_slptime > 5 * loadfac) 584 ts->ts_estcpu = 0; 585 else { 586 newcpu = ts->ts_estcpu; 587 ts->ts_slptime--; /* was incremented in schedcpu() */ 588 while (newcpu && --ts->ts_slptime) 589 newcpu = decay_cpu(loadfac, newcpu); 590 ts->ts_estcpu = newcpu; 591 } 592 } 593 594 /* 595 * Compute the priority of a process when running in user mode. 596 * Arrange to reschedule if the resulting priority is better 597 * than that of the current process. 598 */ 599 static void 600 resetpriority(struct thread *td) 601 { 602 u_int newpriority; 603 604 if (td->td_pri_class != PRI_TIMESHARE) 605 return; 606 newpriority = PUSER + 607 td_get_sched(td)->ts_estcpu / INVERSE_ESTCPU_WEIGHT + 608 NICE_WEIGHT * (td->td_proc->p_nice - PRIO_MIN); 609 newpriority = min(max(newpriority, PRI_MIN_TIMESHARE), 610 PRI_MAX_TIMESHARE); 611 sched_user_prio(td, newpriority); 612 } 613 614 /* 615 * Update the thread's priority when the associated process's user 616 * priority changes. 617 */ 618 static void 619 resetpriority_thread(struct thread *td) 620 { 621 622 /* Only change threads with a time sharing user priority. */ 623 if (td->td_priority < PRI_MIN_TIMESHARE || 624 td->td_priority > PRI_MAX_TIMESHARE) 625 return; 626 627 /* XXX the whole needresched thing is broken, but not silly. */ 628 maybe_resched(td); 629 630 sched_prio(td, td->td_user_pri); 631 } 632 633 /* ARGSUSED */ 634 static void 635 sched_setup(void *dummy) 636 { 637 638 setup_runqs(); 639 640 /* Account for thread0. */ 641 sched_load_add(); 642 } 643 644 /* 645 * This routine determines time constants after stathz and hz are setup. 646 */ 647 static void 648 sched_initticks(void *dummy) 649 { 650 651 realstathz = stathz ? stathz : hz; 652 sched_slice = realstathz / 10; /* ~100ms */ 653 hogticks = imax(1, (2 * hz * sched_slice + realstathz / 2) / 654 realstathz); 655 } 656 657 /* External interfaces start here */ 658 659 /* 660 * Very early in the boot some setup of scheduler-specific 661 * parts of proc0 and of some scheduler resources needs to be done. 662 * Called from: 663 * proc0_init() 664 */ 665 void 666 schedinit(void) 667 { 668 669 /* 670 * Set up the scheduler specific parts of thread0. 671 */ 672 thread0.td_lock = &sched_lock; 673 td_get_sched(&thread0)->ts_slice = sched_slice; 674 mtx_init(&sched_lock, "sched lock", NULL, MTX_SPIN); 675 } 676 677 int 678 sched_runnable(void) 679 { 680 #ifdef SMP 681 return runq_check(&runq) + runq_check(&runq_pcpu[PCPU_GET(cpuid)]); 682 #else 683 return runq_check(&runq); 684 #endif 685 } 686 687 int 688 sched_rr_interval(void) 689 { 690 691 /* Convert sched_slice from stathz to hz. */ 692 return (imax(1, (sched_slice * hz + realstathz / 2) / realstathz)); 693 } 694 695 /* 696 * We adjust the priority of the current process. The priority of a 697 * process gets worse as it accumulates CPU time. The cpu usage 698 * estimator (ts_estcpu) is increased here. resetpriority() will 699 * compute a different priority each time ts_estcpu increases by 700 * INVERSE_ESTCPU_WEIGHT (until PRI_MAX_TIMESHARE is reached). The 701 * cpu usage estimator ramps up quite quickly when the process is 702 * running (linearly), and decays away exponentially, at a rate which 703 * is proportionally slower when the system is busy. The basic 704 * principle is that the system will 90% forget that the process used 705 * a lot of CPU time in 5 * loadav seconds. This causes the system to 706 * favor processes which haven't run much recently, and to round-robin 707 * among other processes. 708 */ 709 static void 710 sched_clock_tick(struct thread *td) 711 { 712 struct pcpuidlestat *stat; 713 struct td_sched *ts; 714 715 THREAD_LOCK_ASSERT(td, MA_OWNED); 716 ts = td_get_sched(td); 717 718 ts->ts_cpticks++; 719 ts->ts_estcpu = ESTCPULIM(ts->ts_estcpu + 1); 720 if ((ts->ts_estcpu % INVERSE_ESTCPU_WEIGHT) == 0) { 721 resetpriority(td); 722 resetpriority_thread(td); 723 } 724 725 /* 726 * Force a context switch if the current thread has used up a full 727 * time slice (default is 100ms). 728 */ 729 if (!TD_IS_IDLETHREAD(td) && --ts->ts_slice <= 0) { 730 ts->ts_slice = sched_slice; 731 td->td_flags |= TDF_NEEDRESCHED | TDF_SLICEEND; 732 } 733 734 stat = DPCPU_PTR(idlestat); 735 stat->oldidlecalls = stat->idlecalls; 736 stat->idlecalls = 0; 737 } 738 739 void 740 sched_clock(struct thread *td, int cnt) 741 { 742 743 for ( ; cnt > 0; cnt--) 744 sched_clock_tick(td); 745 } 746 747 /* 748 * Charge child's scheduling CPU usage to parent. 749 */ 750 void 751 sched_exit(struct proc *p, struct thread *td) 752 { 753 754 KTR_STATE1(KTR_SCHED, "thread", sched_tdname(td), "proc exit", 755 "prio:%d", td->td_priority); 756 757 PROC_LOCK_ASSERT(p, MA_OWNED); 758 sched_exit_thread(FIRST_THREAD_IN_PROC(p), td); 759 } 760 761 void 762 sched_exit_thread(struct thread *td, struct thread *child) 763 { 764 765 KTR_STATE1(KTR_SCHED, "thread", sched_tdname(child), "exit", 766 "prio:%d", child->td_priority); 767 thread_lock(td); 768 td_get_sched(td)->ts_estcpu = ESTCPULIM(td_get_sched(td)->ts_estcpu + 769 td_get_sched(child)->ts_estcpu); 770 thread_unlock(td); 771 thread_lock(child); 772 if ((child->td_flags & TDF_NOLOAD) == 0) 773 sched_load_rem(); 774 thread_unlock(child); 775 } 776 777 void 778 sched_fork(struct thread *td, struct thread *childtd) 779 { 780 sched_fork_thread(td, childtd); 781 } 782 783 void 784 sched_fork_thread(struct thread *td, struct thread *childtd) 785 { 786 struct td_sched *ts, *tsc; 787 788 childtd->td_oncpu = NOCPU; 789 childtd->td_lastcpu = NOCPU; 790 childtd->td_lock = &sched_lock; 791 childtd->td_cpuset = cpuset_ref(td->td_cpuset); 792 childtd->td_domain.dr_policy = td->td_cpuset->cs_domain; 793 childtd->td_priority = childtd->td_base_pri; 794 ts = td_get_sched(childtd); 795 bzero(ts, sizeof(*ts)); 796 tsc = td_get_sched(td); 797 ts->ts_estcpu = tsc->ts_estcpu; 798 ts->ts_flags |= (tsc->ts_flags & TSF_AFFINITY); 799 ts->ts_slice = 1; 800 } 801 802 void 803 sched_nice(struct proc *p, int nice) 804 { 805 struct thread *td; 806 807 PROC_LOCK_ASSERT(p, MA_OWNED); 808 p->p_nice = nice; 809 FOREACH_THREAD_IN_PROC(p, td) { 810 thread_lock(td); 811 resetpriority(td); 812 resetpriority_thread(td); 813 thread_unlock(td); 814 } 815 } 816 817 void 818 sched_class(struct thread *td, int class) 819 { 820 THREAD_LOCK_ASSERT(td, MA_OWNED); 821 td->td_pri_class = class; 822 } 823 824 /* 825 * Adjust the priority of a thread. 826 */ 827 static void 828 sched_priority(struct thread *td, u_char prio) 829 { 830 831 832 KTR_POINT3(KTR_SCHED, "thread", sched_tdname(td), "priority change", 833 "prio:%d", td->td_priority, "new prio:%d", prio, KTR_ATTR_LINKED, 834 sched_tdname(curthread)); 835 SDT_PROBE3(sched, , , change__pri, td, td->td_proc, prio); 836 if (td != curthread && prio > td->td_priority) { 837 KTR_POINT3(KTR_SCHED, "thread", sched_tdname(curthread), 838 "lend prio", "prio:%d", td->td_priority, "new prio:%d", 839 prio, KTR_ATTR_LINKED, sched_tdname(td)); 840 SDT_PROBE4(sched, , , lend__pri, td, td->td_proc, prio, 841 curthread); 842 } 843 THREAD_LOCK_ASSERT(td, MA_OWNED); 844 if (td->td_priority == prio) 845 return; 846 td->td_priority = prio; 847 if (TD_ON_RUNQ(td) && td->td_rqindex != (prio / RQ_PPQ)) { 848 sched_rem(td); 849 sched_add(td, SRQ_BORING | SRQ_HOLDTD); 850 } 851 } 852 853 /* 854 * Update a thread's priority when it is lent another thread's 855 * priority. 856 */ 857 void 858 sched_lend_prio(struct thread *td, u_char prio) 859 { 860 861 td->td_flags |= TDF_BORROWING; 862 sched_priority(td, prio); 863 } 864 865 /* 866 * Restore a thread's priority when priority propagation is 867 * over. The prio argument is the minimum priority the thread 868 * needs to have to satisfy other possible priority lending 869 * requests. If the thread's regulary priority is less 870 * important than prio the thread will keep a priority boost 871 * of prio. 872 */ 873 void 874 sched_unlend_prio(struct thread *td, u_char prio) 875 { 876 u_char base_pri; 877 878 if (td->td_base_pri >= PRI_MIN_TIMESHARE && 879 td->td_base_pri <= PRI_MAX_TIMESHARE) 880 base_pri = td->td_user_pri; 881 else 882 base_pri = td->td_base_pri; 883 if (prio >= base_pri) { 884 td->td_flags &= ~TDF_BORROWING; 885 sched_prio(td, base_pri); 886 } else 887 sched_lend_prio(td, prio); 888 } 889 890 void 891 sched_prio(struct thread *td, u_char prio) 892 { 893 u_char oldprio; 894 895 /* First, update the base priority. */ 896 td->td_base_pri = prio; 897 898 /* 899 * If the thread is borrowing another thread's priority, don't ever 900 * lower the priority. 901 */ 902 if (td->td_flags & TDF_BORROWING && td->td_priority < prio) 903 return; 904 905 /* Change the real priority. */ 906 oldprio = td->td_priority; 907 sched_priority(td, prio); 908 909 /* 910 * If the thread is on a turnstile, then let the turnstile update 911 * its state. 912 */ 913 if (TD_ON_LOCK(td) && oldprio != prio) 914 turnstile_adjust(td, oldprio); 915 } 916 917 void 918 sched_user_prio(struct thread *td, u_char prio) 919 { 920 921 THREAD_LOCK_ASSERT(td, MA_OWNED); 922 td->td_base_user_pri = prio; 923 if (td->td_lend_user_pri <= prio) 924 return; 925 td->td_user_pri = prio; 926 } 927 928 void 929 sched_lend_user_prio(struct thread *td, u_char prio) 930 { 931 932 THREAD_LOCK_ASSERT(td, MA_OWNED); 933 td->td_lend_user_pri = prio; 934 td->td_user_pri = min(prio, td->td_base_user_pri); 935 if (td->td_priority > td->td_user_pri) 936 sched_prio(td, td->td_user_pri); 937 else if (td->td_priority != td->td_user_pri) 938 td->td_flags |= TDF_NEEDRESCHED; 939 } 940 941 /* 942 * Like the above but first check if there is anything to do. 943 */ 944 void 945 sched_lend_user_prio_cond(struct thread *td, u_char prio) 946 { 947 948 if (td->td_lend_user_pri != prio) 949 goto lend; 950 if (td->td_user_pri != min(prio, td->td_base_user_pri)) 951 goto lend; 952 if (td->td_priority >= td->td_user_pri) 953 goto lend; 954 return; 955 956 lend: 957 thread_lock(td); 958 sched_lend_user_prio(td, prio); 959 thread_unlock(td); 960 } 961 962 void 963 sched_sleep(struct thread *td, int pri) 964 { 965 966 THREAD_LOCK_ASSERT(td, MA_OWNED); 967 td->td_slptick = ticks; 968 td_get_sched(td)->ts_slptime = 0; 969 if (pri != 0 && PRI_BASE(td->td_pri_class) == PRI_TIMESHARE) 970 sched_prio(td, pri); 971 if (TD_IS_SUSPENDED(td) || pri >= PSOCK) 972 td->td_flags |= TDF_CANSWAP; 973 } 974 975 void 976 sched_switch(struct thread *td, int flags) 977 { 978 struct thread *newtd; 979 struct mtx *tmtx; 980 struct td_sched *ts; 981 struct proc *p; 982 int preempted; 983 984 tmtx = &sched_lock; 985 ts = td_get_sched(td); 986 p = td->td_proc; 987 988 THREAD_LOCK_ASSERT(td, MA_OWNED); 989 990 td->td_lastcpu = td->td_oncpu; 991 preempted = (td->td_flags & TDF_SLICEEND) == 0 && 992 (flags & SW_PREEMPT) != 0; 993 td->td_flags &= ~(TDF_NEEDRESCHED | TDF_SLICEEND); 994 td->td_owepreempt = 0; 995 td->td_oncpu = NOCPU; 996 997 /* 998 * At the last moment, if this thread is still marked RUNNING, 999 * then put it back on the run queue as it has not been suspended 1000 * or stopped or any thing else similar. We never put the idle 1001 * threads on the run queue, however. 1002 */ 1003 if (td->td_flags & TDF_IDLETD) { 1004 TD_SET_CAN_RUN(td); 1005 #ifdef SMP 1006 CPU_CLR(PCPU_GET(cpuid), &idle_cpus_mask); 1007 #endif 1008 } else { 1009 if (TD_IS_RUNNING(td)) { 1010 /* Put us back on the run queue. */ 1011 sched_add(td, preempted ? 1012 SRQ_HOLDTD|SRQ_OURSELF|SRQ_YIELDING|SRQ_PREEMPTED : 1013 SRQ_HOLDTD|SRQ_OURSELF|SRQ_YIELDING); 1014 } 1015 } 1016 1017 /* 1018 * Switch to the sched lock to fix things up and pick 1019 * a new thread. Block the td_lock in order to avoid 1020 * breaking the critical path. 1021 */ 1022 if (td->td_lock != &sched_lock) { 1023 mtx_lock_spin(&sched_lock); 1024 tmtx = thread_lock_block(td); 1025 mtx_unlock_spin(tmtx); 1026 } 1027 1028 if ((td->td_flags & TDF_NOLOAD) == 0) 1029 sched_load_rem(); 1030 1031 newtd = choosethread(); 1032 MPASS(newtd->td_lock == &sched_lock); 1033 1034 #if (KTR_COMPILE & KTR_SCHED) != 0 1035 if (TD_IS_IDLETHREAD(td)) 1036 KTR_STATE1(KTR_SCHED, "thread", sched_tdname(td), "idle", 1037 "prio:%d", td->td_priority); 1038 else 1039 KTR_STATE3(KTR_SCHED, "thread", sched_tdname(td), KTDSTATE(td), 1040 "prio:%d", td->td_priority, "wmesg:\"%s\"", td->td_wmesg, 1041 "lockname:\"%s\"", td->td_lockname); 1042 #endif 1043 1044 if (td != newtd) { 1045 #ifdef HWPMC_HOOKS 1046 if (PMC_PROC_IS_USING_PMCS(td->td_proc)) 1047 PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_OUT); 1048 #endif 1049 1050 SDT_PROBE2(sched, , , off__cpu, newtd, newtd->td_proc); 1051 1052 /* I feel sleepy */ 1053 lock_profile_release_lock(&sched_lock.lock_object); 1054 #ifdef KDTRACE_HOOKS 1055 /* 1056 * If DTrace has set the active vtime enum to anything 1057 * other than INACTIVE (0), then it should have set the 1058 * function to call. 1059 */ 1060 if (dtrace_vtime_active) 1061 (*dtrace_vtime_switch_func)(newtd); 1062 #endif 1063 1064 cpu_switch(td, newtd, tmtx); 1065 lock_profile_obtain_lock_success(&sched_lock.lock_object, 1066 0, 0, __FILE__, __LINE__); 1067 /* 1068 * Where am I? What year is it? 1069 * We are in the same thread that went to sleep above, 1070 * but any amount of time may have passed. All our context 1071 * will still be available as will local variables. 1072 * PCPU values however may have changed as we may have 1073 * changed CPU so don't trust cached values of them. 1074 * New threads will go to fork_exit() instead of here 1075 * so if you change things here you may need to change 1076 * things there too. 1077 * 1078 * If the thread above was exiting it will never wake 1079 * up again here, so either it has saved everything it 1080 * needed to, or the thread_wait() or wait() will 1081 * need to reap it. 1082 */ 1083 1084 SDT_PROBE0(sched, , , on__cpu); 1085 #ifdef HWPMC_HOOKS 1086 if (PMC_PROC_IS_USING_PMCS(td->td_proc)) 1087 PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_IN); 1088 #endif 1089 } else { 1090 td->td_lock = &sched_lock; 1091 SDT_PROBE0(sched, , , remain__cpu); 1092 } 1093 1094 KTR_STATE1(KTR_SCHED, "thread", sched_tdname(td), "running", 1095 "prio:%d", td->td_priority); 1096 1097 #ifdef SMP 1098 if (td->td_flags & TDF_IDLETD) 1099 CPU_SET(PCPU_GET(cpuid), &idle_cpus_mask); 1100 #endif 1101 sched_lock.mtx_lock = (uintptr_t)td; 1102 td->td_oncpu = PCPU_GET(cpuid); 1103 spinlock_enter(); 1104 mtx_unlock_spin(&sched_lock); 1105 } 1106 1107 void 1108 sched_wakeup(struct thread *td, int srqflags) 1109 { 1110 struct td_sched *ts; 1111 1112 THREAD_LOCK_ASSERT(td, MA_OWNED); 1113 ts = td_get_sched(td); 1114 td->td_flags &= ~TDF_CANSWAP; 1115 if (ts->ts_slptime > 1) { 1116 updatepri(td); 1117 resetpriority(td); 1118 } 1119 td->td_slptick = 0; 1120 ts->ts_slptime = 0; 1121 ts->ts_slice = sched_slice; 1122 sched_add(td, srqflags); 1123 } 1124 1125 #ifdef SMP 1126 static int 1127 forward_wakeup(int cpunum) 1128 { 1129 struct pcpu *pc; 1130 cpuset_t dontuse, map, map2; 1131 u_int id, me; 1132 int iscpuset; 1133 1134 mtx_assert(&sched_lock, MA_OWNED); 1135 1136 CTR0(KTR_RUNQ, "forward_wakeup()"); 1137 1138 if ((!forward_wakeup_enabled) || 1139 (forward_wakeup_use_mask == 0 && forward_wakeup_use_loop == 0)) 1140 return (0); 1141 if (!smp_started || KERNEL_PANICKED()) 1142 return (0); 1143 1144 forward_wakeups_requested++; 1145 1146 /* 1147 * Check the idle mask we received against what we calculated 1148 * before in the old version. 1149 */ 1150 me = PCPU_GET(cpuid); 1151 1152 /* Don't bother if we should be doing it ourself. */ 1153 if (CPU_ISSET(me, &idle_cpus_mask) && 1154 (cpunum == NOCPU || me == cpunum)) 1155 return (0); 1156 1157 CPU_SETOF(me, &dontuse); 1158 CPU_OR(&dontuse, &stopped_cpus); 1159 CPU_OR(&dontuse, &hlt_cpus_mask); 1160 CPU_ZERO(&map2); 1161 if (forward_wakeup_use_loop) { 1162 STAILQ_FOREACH(pc, &cpuhead, pc_allcpu) { 1163 id = pc->pc_cpuid; 1164 if (!CPU_ISSET(id, &dontuse) && 1165 pc->pc_curthread == pc->pc_idlethread) { 1166 CPU_SET(id, &map2); 1167 } 1168 } 1169 } 1170 1171 if (forward_wakeup_use_mask) { 1172 map = idle_cpus_mask; 1173 CPU_ANDNOT(&map, &dontuse); 1174 1175 /* If they are both on, compare and use loop if different. */ 1176 if (forward_wakeup_use_loop) { 1177 if (CPU_CMP(&map, &map2)) { 1178 printf("map != map2, loop method preferred\n"); 1179 map = map2; 1180 } 1181 } 1182 } else { 1183 map = map2; 1184 } 1185 1186 /* If we only allow a specific CPU, then mask off all the others. */ 1187 if (cpunum != NOCPU) { 1188 KASSERT((cpunum <= mp_maxcpus),("forward_wakeup: bad cpunum.")); 1189 iscpuset = CPU_ISSET(cpunum, &map); 1190 if (iscpuset == 0) 1191 CPU_ZERO(&map); 1192 else 1193 CPU_SETOF(cpunum, &map); 1194 } 1195 if (!CPU_EMPTY(&map)) { 1196 forward_wakeups_delivered++; 1197 STAILQ_FOREACH(pc, &cpuhead, pc_allcpu) { 1198 id = pc->pc_cpuid; 1199 if (!CPU_ISSET(id, &map)) 1200 continue; 1201 if (cpu_idle_wakeup(pc->pc_cpuid)) 1202 CPU_CLR(id, &map); 1203 } 1204 if (!CPU_EMPTY(&map)) 1205 ipi_selected(map, IPI_AST); 1206 return (1); 1207 } 1208 if (cpunum == NOCPU) 1209 printf("forward_wakeup: Idle processor not found\n"); 1210 return (0); 1211 } 1212 1213 static void 1214 kick_other_cpu(int pri, int cpuid) 1215 { 1216 struct pcpu *pcpu; 1217 int cpri; 1218 1219 pcpu = pcpu_find(cpuid); 1220 if (CPU_ISSET(cpuid, &idle_cpus_mask)) { 1221 forward_wakeups_delivered++; 1222 if (!cpu_idle_wakeup(cpuid)) 1223 ipi_cpu(cpuid, IPI_AST); 1224 return; 1225 } 1226 1227 cpri = pcpu->pc_curthread->td_priority; 1228 if (pri >= cpri) 1229 return; 1230 1231 #if defined(IPI_PREEMPTION) && defined(PREEMPTION) 1232 #if !defined(FULL_PREEMPTION) 1233 if (pri <= PRI_MAX_ITHD) 1234 #endif /* ! FULL_PREEMPTION */ 1235 { 1236 ipi_cpu(cpuid, IPI_PREEMPT); 1237 return; 1238 } 1239 #endif /* defined(IPI_PREEMPTION) && defined(PREEMPTION) */ 1240 1241 pcpu->pc_curthread->td_flags |= TDF_NEEDRESCHED; 1242 ipi_cpu(cpuid, IPI_AST); 1243 return; 1244 } 1245 #endif /* SMP */ 1246 1247 #ifdef SMP 1248 static int 1249 sched_pickcpu(struct thread *td) 1250 { 1251 int best, cpu; 1252 1253 mtx_assert(&sched_lock, MA_OWNED); 1254 1255 if (td->td_lastcpu != NOCPU && THREAD_CAN_SCHED(td, td->td_lastcpu)) 1256 best = td->td_lastcpu; 1257 else 1258 best = NOCPU; 1259 CPU_FOREACH(cpu) { 1260 if (!THREAD_CAN_SCHED(td, cpu)) 1261 continue; 1262 1263 if (best == NOCPU) 1264 best = cpu; 1265 else if (runq_length[cpu] < runq_length[best]) 1266 best = cpu; 1267 } 1268 KASSERT(best != NOCPU, ("no valid CPUs")); 1269 1270 return (best); 1271 } 1272 #endif 1273 1274 void 1275 sched_add(struct thread *td, int flags) 1276 #ifdef SMP 1277 { 1278 cpuset_t tidlemsk; 1279 struct td_sched *ts; 1280 u_int cpu, cpuid; 1281 int forwarded = 0; 1282 int single_cpu = 0; 1283 1284 ts = td_get_sched(td); 1285 THREAD_LOCK_ASSERT(td, MA_OWNED); 1286 KASSERT((td->td_inhibitors == 0), 1287 ("sched_add: trying to run inhibited thread")); 1288 KASSERT((TD_CAN_RUN(td) || TD_IS_RUNNING(td)), 1289 ("sched_add: bad thread state")); 1290 KASSERT(td->td_flags & TDF_INMEM, 1291 ("sched_add: thread swapped out")); 1292 1293 KTR_STATE2(KTR_SCHED, "thread", sched_tdname(td), "runq add", 1294 "prio:%d", td->td_priority, KTR_ATTR_LINKED, 1295 sched_tdname(curthread)); 1296 KTR_POINT1(KTR_SCHED, "thread", sched_tdname(curthread), "wokeup", 1297 KTR_ATTR_LINKED, sched_tdname(td)); 1298 SDT_PROBE4(sched, , , enqueue, td, td->td_proc, NULL, 1299 flags & SRQ_PREEMPTED); 1300 1301 1302 /* 1303 * Now that the thread is moving to the run-queue, set the lock 1304 * to the scheduler's lock. 1305 */ 1306 if (td->td_lock != &sched_lock) { 1307 mtx_lock_spin(&sched_lock); 1308 if ((flags & SRQ_HOLD) != 0) 1309 td->td_lock = &sched_lock; 1310 else 1311 thread_lock_set(td, &sched_lock); 1312 1313 } 1314 TD_SET_RUNQ(td); 1315 1316 /* 1317 * If SMP is started and the thread is pinned or otherwise limited to 1318 * a specific set of CPUs, queue the thread to a per-CPU run queue. 1319 * Otherwise, queue the thread to the global run queue. 1320 * 1321 * If SMP has not yet been started we must use the global run queue 1322 * as per-CPU state may not be initialized yet and we may crash if we 1323 * try to access the per-CPU run queues. 1324 */ 1325 if (smp_started && (td->td_pinned != 0 || td->td_flags & TDF_BOUND || 1326 ts->ts_flags & TSF_AFFINITY)) { 1327 if (td->td_pinned != 0) 1328 cpu = td->td_lastcpu; 1329 else if (td->td_flags & TDF_BOUND) { 1330 /* Find CPU from bound runq. */ 1331 KASSERT(SKE_RUNQ_PCPU(ts), 1332 ("sched_add: bound td_sched not on cpu runq")); 1333 cpu = ts->ts_runq - &runq_pcpu[0]; 1334 } else 1335 /* Find a valid CPU for our cpuset */ 1336 cpu = sched_pickcpu(td); 1337 ts->ts_runq = &runq_pcpu[cpu]; 1338 single_cpu = 1; 1339 CTR3(KTR_RUNQ, 1340 "sched_add: Put td_sched:%p(td:%p) on cpu%d runq", ts, td, 1341 cpu); 1342 } else { 1343 CTR2(KTR_RUNQ, 1344 "sched_add: adding td_sched:%p (td:%p) to gbl runq", ts, 1345 td); 1346 cpu = NOCPU; 1347 ts->ts_runq = &runq; 1348 } 1349 1350 if ((td->td_flags & TDF_NOLOAD) == 0) 1351 sched_load_add(); 1352 runq_add(ts->ts_runq, td, flags); 1353 if (cpu != NOCPU) 1354 runq_length[cpu]++; 1355 1356 cpuid = PCPU_GET(cpuid); 1357 if (single_cpu && cpu != cpuid) { 1358 kick_other_cpu(td->td_priority, cpu); 1359 } else { 1360 if (!single_cpu) { 1361 tidlemsk = idle_cpus_mask; 1362 CPU_ANDNOT(&tidlemsk, &hlt_cpus_mask); 1363 CPU_CLR(cpuid, &tidlemsk); 1364 1365 if (!CPU_ISSET(cpuid, &idle_cpus_mask) && 1366 ((flags & SRQ_INTR) == 0) && 1367 !CPU_EMPTY(&tidlemsk)) 1368 forwarded = forward_wakeup(cpu); 1369 } 1370 1371 if (!forwarded) { 1372 if (!maybe_preempt(td)) 1373 maybe_resched(td); 1374 } 1375 } 1376 if ((flags & SRQ_HOLDTD) == 0) 1377 thread_unlock(td); 1378 } 1379 #else /* SMP */ 1380 { 1381 struct td_sched *ts; 1382 1383 ts = td_get_sched(td); 1384 THREAD_LOCK_ASSERT(td, MA_OWNED); 1385 KASSERT((td->td_inhibitors == 0), 1386 ("sched_add: trying to run inhibited thread")); 1387 KASSERT((TD_CAN_RUN(td) || TD_IS_RUNNING(td)), 1388 ("sched_add: bad thread state")); 1389 KASSERT(td->td_flags & TDF_INMEM, 1390 ("sched_add: thread swapped out")); 1391 KTR_STATE2(KTR_SCHED, "thread", sched_tdname(td), "runq add", 1392 "prio:%d", td->td_priority, KTR_ATTR_LINKED, 1393 sched_tdname(curthread)); 1394 KTR_POINT1(KTR_SCHED, "thread", sched_tdname(curthread), "wokeup", 1395 KTR_ATTR_LINKED, sched_tdname(td)); 1396 SDT_PROBE4(sched, , , enqueue, td, td->td_proc, NULL, 1397 flags & SRQ_PREEMPTED); 1398 1399 /* 1400 * Now that the thread is moving to the run-queue, set the lock 1401 * to the scheduler's lock. 1402 */ 1403 if (td->td_lock != &sched_lock) { 1404 mtx_lock_spin(&sched_lock); 1405 if ((flags & SRQ_HOLD) != 0) 1406 td->td_lock = &sched_lock; 1407 else 1408 thread_lock_set(td, &sched_lock); 1409 } 1410 TD_SET_RUNQ(td); 1411 CTR2(KTR_RUNQ, "sched_add: adding td_sched:%p (td:%p) to runq", ts, td); 1412 ts->ts_runq = &runq; 1413 1414 if ((td->td_flags & TDF_NOLOAD) == 0) 1415 sched_load_add(); 1416 runq_add(ts->ts_runq, td, flags); 1417 if (!maybe_preempt(td)) 1418 maybe_resched(td); 1419 if ((flags & SRQ_HOLDTD) == 0) 1420 thread_unlock(td); 1421 } 1422 #endif /* SMP */ 1423 1424 void 1425 sched_rem(struct thread *td) 1426 { 1427 struct td_sched *ts; 1428 1429 ts = td_get_sched(td); 1430 KASSERT(td->td_flags & TDF_INMEM, 1431 ("sched_rem: thread swapped out")); 1432 KASSERT(TD_ON_RUNQ(td), 1433 ("sched_rem: thread not on run queue")); 1434 mtx_assert(&sched_lock, MA_OWNED); 1435 KTR_STATE2(KTR_SCHED, "thread", sched_tdname(td), "runq rem", 1436 "prio:%d", td->td_priority, KTR_ATTR_LINKED, 1437 sched_tdname(curthread)); 1438 SDT_PROBE3(sched, , , dequeue, td, td->td_proc, NULL); 1439 1440 if ((td->td_flags & TDF_NOLOAD) == 0) 1441 sched_load_rem(); 1442 #ifdef SMP 1443 if (ts->ts_runq != &runq) 1444 runq_length[ts->ts_runq - runq_pcpu]--; 1445 #endif 1446 runq_remove(ts->ts_runq, td); 1447 TD_SET_CAN_RUN(td); 1448 } 1449 1450 /* 1451 * Select threads to run. Note that running threads still consume a 1452 * slot. 1453 */ 1454 struct thread * 1455 sched_choose(void) 1456 { 1457 struct thread *td; 1458 struct runq *rq; 1459 1460 mtx_assert(&sched_lock, MA_OWNED); 1461 #ifdef SMP 1462 struct thread *tdcpu; 1463 1464 rq = &runq; 1465 td = runq_choose_fuzz(&runq, runq_fuzz); 1466 tdcpu = runq_choose(&runq_pcpu[PCPU_GET(cpuid)]); 1467 1468 if (td == NULL || 1469 (tdcpu != NULL && 1470 tdcpu->td_priority < td->td_priority)) { 1471 CTR2(KTR_RUNQ, "choosing td %p from pcpu runq %d", tdcpu, 1472 PCPU_GET(cpuid)); 1473 td = tdcpu; 1474 rq = &runq_pcpu[PCPU_GET(cpuid)]; 1475 } else { 1476 CTR1(KTR_RUNQ, "choosing td_sched %p from main runq", td); 1477 } 1478 1479 #else 1480 rq = &runq; 1481 td = runq_choose(&runq); 1482 #endif 1483 1484 if (td) { 1485 #ifdef SMP 1486 if (td == tdcpu) 1487 runq_length[PCPU_GET(cpuid)]--; 1488 #endif 1489 runq_remove(rq, td); 1490 td->td_flags |= TDF_DIDRUN; 1491 1492 KASSERT(td->td_flags & TDF_INMEM, 1493 ("sched_choose: thread swapped out")); 1494 return (td); 1495 } 1496 return (PCPU_GET(idlethread)); 1497 } 1498 1499 void 1500 sched_preempt(struct thread *td) 1501 { 1502 1503 SDT_PROBE2(sched, , , surrender, td, td->td_proc); 1504 if (td->td_critnest > 1) { 1505 td->td_owepreempt = 1; 1506 } else { 1507 thread_lock(td); 1508 mi_switch(SW_INVOL | SW_PREEMPT | SWT_PREEMPT); 1509 } 1510 } 1511 1512 void 1513 sched_userret_slowpath(struct thread *td) 1514 { 1515 1516 thread_lock(td); 1517 td->td_priority = td->td_user_pri; 1518 td->td_base_pri = td->td_user_pri; 1519 thread_unlock(td); 1520 } 1521 1522 void 1523 sched_bind(struct thread *td, int cpu) 1524 { 1525 struct td_sched *ts; 1526 1527 THREAD_LOCK_ASSERT(td, MA_OWNED|MA_NOTRECURSED); 1528 KASSERT(td == curthread, ("sched_bind: can only bind curthread")); 1529 1530 ts = td_get_sched(td); 1531 1532 td->td_flags |= TDF_BOUND; 1533 #ifdef SMP 1534 ts->ts_runq = &runq_pcpu[cpu]; 1535 if (PCPU_GET(cpuid) == cpu) 1536 return; 1537 1538 mi_switch(SW_VOL); 1539 thread_lock(td); 1540 #endif 1541 } 1542 1543 void 1544 sched_unbind(struct thread* td) 1545 { 1546 THREAD_LOCK_ASSERT(td, MA_OWNED); 1547 KASSERT(td == curthread, ("sched_unbind: can only bind curthread")); 1548 td->td_flags &= ~TDF_BOUND; 1549 } 1550 1551 int 1552 sched_is_bound(struct thread *td) 1553 { 1554 THREAD_LOCK_ASSERT(td, MA_OWNED); 1555 return (td->td_flags & TDF_BOUND); 1556 } 1557 1558 void 1559 sched_relinquish(struct thread *td) 1560 { 1561 thread_lock(td); 1562 mi_switch(SW_VOL | SWT_RELINQUISH); 1563 } 1564 1565 int 1566 sched_load(void) 1567 { 1568 return (sched_tdcnt); 1569 } 1570 1571 int 1572 sched_sizeof_proc(void) 1573 { 1574 return (sizeof(struct proc)); 1575 } 1576 1577 int 1578 sched_sizeof_thread(void) 1579 { 1580 return (sizeof(struct thread) + sizeof(struct td_sched)); 1581 } 1582 1583 fixpt_t 1584 sched_pctcpu(struct thread *td) 1585 { 1586 struct td_sched *ts; 1587 1588 THREAD_LOCK_ASSERT(td, MA_OWNED); 1589 ts = td_get_sched(td); 1590 return (ts->ts_pctcpu); 1591 } 1592 1593 #ifdef RACCT 1594 /* 1595 * Calculates the contribution to the thread cpu usage for the latest 1596 * (unfinished) second. 1597 */ 1598 fixpt_t 1599 sched_pctcpu_delta(struct thread *td) 1600 { 1601 struct td_sched *ts; 1602 fixpt_t delta; 1603 int realstathz; 1604 1605 THREAD_LOCK_ASSERT(td, MA_OWNED); 1606 ts = td_get_sched(td); 1607 delta = 0; 1608 realstathz = stathz ? stathz : hz; 1609 if (ts->ts_cpticks != 0) { 1610 #if (FSHIFT >= CCPU_SHIFT) 1611 delta = (realstathz == 100) 1612 ? ((fixpt_t) ts->ts_cpticks) << 1613 (FSHIFT - CCPU_SHIFT) : 1614 100 * (((fixpt_t) ts->ts_cpticks) 1615 << (FSHIFT - CCPU_SHIFT)) / realstathz; 1616 #else 1617 delta = ((FSCALE - ccpu) * 1618 (ts->ts_cpticks * 1619 FSCALE / realstathz)) >> FSHIFT; 1620 #endif 1621 } 1622 1623 return (delta); 1624 } 1625 #endif 1626 1627 u_int 1628 sched_estcpu(struct thread *td) 1629 { 1630 1631 return (td_get_sched(td)->ts_estcpu); 1632 } 1633 1634 /* 1635 * The actual idle process. 1636 */ 1637 void 1638 sched_idletd(void *dummy) 1639 { 1640 struct pcpuidlestat *stat; 1641 1642 THREAD_NO_SLEEPING(); 1643 stat = DPCPU_PTR(idlestat); 1644 for (;;) { 1645 mtx_assert(&Giant, MA_NOTOWNED); 1646 1647 while (sched_runnable() == 0) { 1648 cpu_idle(stat->idlecalls + stat->oldidlecalls > 64); 1649 stat->idlecalls++; 1650 } 1651 1652 mtx_lock_spin(&sched_lock); 1653 mi_switch(SW_VOL | SWT_IDLE); 1654 } 1655 } 1656 1657 /* 1658 * A CPU is entering for the first time or a thread is exiting. 1659 */ 1660 void 1661 sched_throw(struct thread *td) 1662 { 1663 /* 1664 * Correct spinlock nesting. The idle thread context that we are 1665 * borrowing was created so that it would start out with a single 1666 * spin lock (sched_lock) held in fork_trampoline(). Since we've 1667 * explicitly acquired locks in this function, the nesting count 1668 * is now 2 rather than 1. Since we are nested, calling 1669 * spinlock_exit() will simply adjust the counts without allowing 1670 * spin lock using code to interrupt us. 1671 */ 1672 if (td == NULL) { 1673 mtx_lock_spin(&sched_lock); 1674 spinlock_exit(); 1675 PCPU_SET(switchtime, cpu_ticks()); 1676 PCPU_SET(switchticks, ticks); 1677 } else { 1678 lock_profile_release_lock(&sched_lock.lock_object); 1679 MPASS(td->td_lock == &sched_lock); 1680 td->td_lastcpu = td->td_oncpu; 1681 td->td_oncpu = NOCPU; 1682 } 1683 mtx_assert(&sched_lock, MA_OWNED); 1684 KASSERT(curthread->td_md.md_spinlock_count == 1, ("invalid count")); 1685 cpu_throw(td, choosethread()); /* doesn't return */ 1686 } 1687 1688 void 1689 sched_fork_exit(struct thread *td) 1690 { 1691 1692 /* 1693 * Finish setting up thread glue so that it begins execution in a 1694 * non-nested critical section with sched_lock held but not recursed. 1695 */ 1696 td->td_oncpu = PCPU_GET(cpuid); 1697 sched_lock.mtx_lock = (uintptr_t)td; 1698 lock_profile_obtain_lock_success(&sched_lock.lock_object, 1699 0, 0, __FILE__, __LINE__); 1700 THREAD_LOCK_ASSERT(td, MA_OWNED | MA_NOTRECURSED); 1701 1702 KTR_STATE1(KTR_SCHED, "thread", sched_tdname(td), "running", 1703 "prio:%d", td->td_priority); 1704 SDT_PROBE0(sched, , , on__cpu); 1705 } 1706 1707 char * 1708 sched_tdname(struct thread *td) 1709 { 1710 #ifdef KTR 1711 struct td_sched *ts; 1712 1713 ts = td_get_sched(td); 1714 if (ts->ts_name[0] == '\0') 1715 snprintf(ts->ts_name, sizeof(ts->ts_name), 1716 "%s tid %d", td->td_name, td->td_tid); 1717 return (ts->ts_name); 1718 #else 1719 return (td->td_name); 1720 #endif 1721 } 1722 1723 #ifdef KTR 1724 void 1725 sched_clear_tdname(struct thread *td) 1726 { 1727 struct td_sched *ts; 1728 1729 ts = td_get_sched(td); 1730 ts->ts_name[0] = '\0'; 1731 } 1732 #endif 1733 1734 void 1735 sched_affinity(struct thread *td) 1736 { 1737 #ifdef SMP 1738 struct td_sched *ts; 1739 int cpu; 1740 1741 THREAD_LOCK_ASSERT(td, MA_OWNED); 1742 1743 /* 1744 * Set the TSF_AFFINITY flag if there is at least one CPU this 1745 * thread can't run on. 1746 */ 1747 ts = td_get_sched(td); 1748 ts->ts_flags &= ~TSF_AFFINITY; 1749 CPU_FOREACH(cpu) { 1750 if (!THREAD_CAN_SCHED(td, cpu)) { 1751 ts->ts_flags |= TSF_AFFINITY; 1752 break; 1753 } 1754 } 1755 1756 /* 1757 * If this thread can run on all CPUs, nothing else to do. 1758 */ 1759 if (!(ts->ts_flags & TSF_AFFINITY)) 1760 return; 1761 1762 /* Pinned threads and bound threads should be left alone. */ 1763 if (td->td_pinned != 0 || td->td_flags & TDF_BOUND) 1764 return; 1765 1766 switch (td->td_state) { 1767 case TDS_RUNQ: 1768 /* 1769 * If we are on a per-CPU runqueue that is in the set, 1770 * then nothing needs to be done. 1771 */ 1772 if (ts->ts_runq != &runq && 1773 THREAD_CAN_SCHED(td, ts->ts_runq - runq_pcpu)) 1774 return; 1775 1776 /* Put this thread on a valid per-CPU runqueue. */ 1777 sched_rem(td); 1778 sched_add(td, SRQ_HOLDTD | SRQ_BORING); 1779 break; 1780 case TDS_RUNNING: 1781 /* 1782 * See if our current CPU is in the set. If not, force a 1783 * context switch. 1784 */ 1785 if (THREAD_CAN_SCHED(td, td->td_oncpu)) 1786 return; 1787 1788 td->td_flags |= TDF_NEEDRESCHED; 1789 if (td != curthread) 1790 ipi_cpu(cpu, IPI_AST); 1791 break; 1792 default: 1793 break; 1794 } 1795 #endif 1796 } 1797