1 /* $NetBSD: sched_4bsd.c,v 1.10 2007/12/15 03:31:36 ad Exp $ */ 2 3 /*- 4 * Copyright (c) 1999, 2000, 2004, 2006, 2007 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility, 9 * NASA Ames Research Center, by Charles M. Hannum, Andrew Doran, and 10 * Daniel Sieger. 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. All advertising materials mentioning features or use of this software 21 * must display the following acknowledgement: 22 * This product includes software developed by the NetBSD 23 * Foundation, Inc. and its contributors. 24 * 4. Neither the name of The NetBSD Foundation nor the names of its 25 * contributors may be used to endorse or promote products derived 26 * from this software without specific prior written permission. 27 * 28 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 29 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 30 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 31 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 32 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 33 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 34 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 35 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 36 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 37 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 38 * POSSIBILITY OF SUCH DAMAGE. 39 */ 40 41 /*- 42 * Copyright (c) 1982, 1986, 1990, 1991, 1993 43 * The Regents of the University of California. All rights reserved. 44 * (c) UNIX System Laboratories, Inc. 45 * All or some portions of this file are derived from material licensed 46 * to the University of California by American Telephone and Telegraph 47 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 48 * the permission of UNIX System Laboratories, Inc. 49 * 50 * Redistribution and use in source and binary forms, with or without 51 * modification, are permitted provided that the following conditions 52 * are met: 53 * 1. Redistributions of source code must retain the above copyright 54 * notice, this list of conditions and the following disclaimer. 55 * 2. Redistributions in binary form must reproduce the above copyright 56 * notice, this list of conditions and the following disclaimer in the 57 * documentation and/or other materials provided with the distribution. 58 * 3. Neither the name of the University nor the names of its contributors 59 * may be used to endorse or promote products derived from this software 60 * without specific prior written permission. 61 * 62 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 63 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 64 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 65 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 66 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 67 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 68 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 69 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 70 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 71 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 72 * SUCH DAMAGE. 73 * 74 * @(#)kern_synch.c 8.9 (Berkeley) 5/19/95 75 */ 76 77 #include <sys/cdefs.h> 78 __KERNEL_RCSID(0, "$NetBSD: sched_4bsd.c,v 1.10 2007/12/15 03:31:36 ad Exp $"); 79 80 #include "opt_ddb.h" 81 #include "opt_lockdebug.h" 82 #include "opt_perfctrs.h" 83 84 #define __MUTEX_PRIVATE 85 86 #include <sys/param.h> 87 #include <sys/systm.h> 88 #include <sys/callout.h> 89 #include <sys/cpu.h> 90 #include <sys/proc.h> 91 #include <sys/kernel.h> 92 #include <sys/signalvar.h> 93 #include <sys/resourcevar.h> 94 #include <sys/sched.h> 95 #include <sys/sysctl.h> 96 #include <sys/kauth.h> 97 #include <sys/lockdebug.h> 98 #include <sys/kmem.h> 99 #include <sys/intr.h> 100 101 #include <uvm/uvm_extern.h> 102 103 /* 104 * Run queues. 105 * 106 * We maintain bitmasks of non-empty queues in order speed up finding 107 * the first runnable process. Since there can be (by definition) few 108 * real time LWPs in the the system, we maintain them on a linked list, 109 * sorted by priority. 110 */ 111 112 #define PPB_SHIFT 5 113 #define PPB_MASK 31 114 115 #define NUM_Q (NPRI_KERNEL + NPRI_USER) 116 #define NUM_PPB (1 << PPB_SHIFT) 117 #define NUM_B (NUM_Q / NUM_PPB) 118 119 typedef struct runqueue { 120 TAILQ_HEAD(, lwp) rq_fixedpri; /* realtime, kthread */ 121 u_int rq_count; /* total # jobs */ 122 uint32_t rq_bitmap[NUM_B]; /* bitmap of queues */ 123 TAILQ_HEAD(, lwp) rq_queue[NUM_Q]; /* user+kernel */ 124 } runqueue_t; 125 126 static runqueue_t global_queue; 127 128 static void updatepri(struct lwp *); 129 static void resetpriority(struct lwp *); 130 131 fixpt_t decay_cpu(fixpt_t, fixpt_t); 132 133 extern unsigned int sched_pstats_ticks; /* defined in kern_synch.c */ 134 135 /* The global scheduler state */ 136 kmutex_t runqueue_lock; 137 138 /* Number of hardclock ticks per sched_tick() */ 139 int rrticks; 140 141 const int schedppq = 1; 142 143 /* 144 * Force switch among equal priority processes every 100ms. 145 * Called from hardclock every hz/10 == rrticks hardclock ticks. 146 * 147 * There's no need to lock anywhere in this routine, as it's 148 * CPU-local and runs at IPL_SCHED (called from clock interrupt). 149 */ 150 /* ARGSUSED */ 151 void 152 sched_tick(struct cpu_info *ci) 153 { 154 struct schedstate_percpu *spc = &ci->ci_schedstate; 155 156 spc->spc_ticks = rrticks; 157 158 if (CURCPU_IDLE_P()) 159 return; 160 161 if (spc->spc_flags & SPCF_SEENRR) { 162 /* 163 * The process has already been through a roundrobin 164 * without switching and may be hogging the CPU. 165 * Indicate that the process should yield. 166 */ 167 spc->spc_flags |= SPCF_SHOULDYIELD; 168 } else 169 spc->spc_flags |= SPCF_SEENRR; 170 171 cpu_need_resched(ci, 0); 172 } 173 174 /* 175 * Why PRIO_MAX - 2? From setpriority(2): 176 * 177 * prio is a value in the range -20 to 20. The default priority is 178 * 0; lower priorities cause more favorable scheduling. A value of 179 * 19 or 20 will schedule a process only when nothing at priority <= 180 * 0 is runnable. 181 * 182 * This gives estcpu influence over 18 priority levels, and leaves nice 183 * with 40 levels. One way to think about it is that nice has 20 levels 184 * either side of estcpu's 18. 185 */ 186 #define ESTCPU_SHIFT 11 187 #define ESTCPU_MAX ((PRIO_MAX - 2) << ESTCPU_SHIFT) 188 #define ESTCPU_ACCUM (1 << (ESTCPU_SHIFT - 1)) 189 #define ESTCPULIM(e) min((e), ESTCPU_MAX) 190 191 /* 192 * Constants for digital decay and forget: 193 * 90% of (l_estcpu) usage in 5 * loadav time 194 * 95% of (l_pctcpu) usage in 60 seconds (load insensitive) 195 * Note that, as ps(1) mentions, this can let percentages 196 * total over 100% (I've seen 137.9% for 3 processes). 197 * 198 * Note that hardclock updates l_estcpu and l_cpticks independently. 199 * 200 * We wish to decay away 90% of l_estcpu in (5 * loadavg) seconds. 201 * That is, the system wants to compute a value of decay such 202 * that the following for loop: 203 * for (i = 0; i < (5 * loadavg); i++) 204 * l_estcpu *= decay; 205 * will compute 206 * l_estcpu *= 0.1; 207 * for all values of loadavg: 208 * 209 * Mathematically this loop can be expressed by saying: 210 * decay ** (5 * loadavg) ~= .1 211 * 212 * The system computes decay as: 213 * decay = (2 * loadavg) / (2 * loadavg + 1) 214 * 215 * We wish to prove that the system's computation of decay 216 * will always fulfill the equation: 217 * decay ** (5 * loadavg) ~= .1 218 * 219 * If we compute b as: 220 * b = 2 * loadavg 221 * then 222 * decay = b / (b + 1) 223 * 224 * We now need to prove two things: 225 * 1) Given factor ** (5 * loadavg) ~= .1, prove factor == b/(b+1) 226 * 2) Given b/(b+1) ** power ~= .1, prove power == (5 * loadavg) 227 * 228 * Facts: 229 * For x close to zero, exp(x) =~ 1 + x, since 230 * exp(x) = 0! + x**1/1! + x**2/2! + ... . 231 * therefore exp(-1/b) =~ 1 - (1/b) = (b-1)/b. 232 * For x close to zero, ln(1+x) =~ x, since 233 * ln(1+x) = x - x**2/2 + x**3/3 - ... -1 < x < 1 234 * therefore ln(b/(b+1)) = ln(1 - 1/(b+1)) =~ -1/(b+1). 235 * ln(.1) =~ -2.30 236 * 237 * Proof of (1): 238 * Solve (factor)**(power) =~ .1 given power (5*loadav): 239 * solving for factor, 240 * ln(factor) =~ (-2.30/5*loadav), or 241 * factor =~ exp(-1/((5/2.30)*loadav)) =~ exp(-1/(2*loadav)) = 242 * exp(-1/b) =~ (b-1)/b =~ b/(b+1). QED 243 * 244 * Proof of (2): 245 * Solve (factor)**(power) =~ .1 given factor == (b/(b+1)): 246 * solving for power, 247 * power*ln(b/(b+1)) =~ -2.30, or 248 * power =~ 2.3 * (b + 1) = 4.6*loadav + 2.3 =~ 5*loadav. QED 249 * 250 * Actual power values for the implemented algorithm are as follows: 251 * loadav: 1 2 3 4 252 * power: 5.68 10.32 14.94 19.55 253 */ 254 255 /* calculations for digital decay to forget 90% of usage in 5*loadav sec */ 256 #define loadfactor(loadav) (2 * (loadav)) 257 258 fixpt_t 259 decay_cpu(fixpt_t loadfac, fixpt_t estcpu) 260 { 261 262 if (estcpu == 0) { 263 return 0; 264 } 265 266 #if !defined(_LP64) 267 /* avoid 64bit arithmetics. */ 268 #define FIXPT_MAX ((fixpt_t)((UINTMAX_C(1) << sizeof(fixpt_t) * CHAR_BIT) - 1)) 269 if (__predict_true(loadfac <= FIXPT_MAX / ESTCPU_MAX)) { 270 return estcpu * loadfac / (loadfac + FSCALE); 271 } 272 #endif /* !defined(_LP64) */ 273 274 return (uint64_t)estcpu * loadfac / (loadfac + FSCALE); 275 } 276 277 /* 278 * For all load averages >= 1 and max l_estcpu of (255 << ESTCPU_SHIFT), 279 * sleeping for at least seven times the loadfactor will decay l_estcpu to 280 * less than (1 << ESTCPU_SHIFT). 281 * 282 * note that our ESTCPU_MAX is actually much smaller than (255 << ESTCPU_SHIFT). 283 */ 284 static fixpt_t 285 decay_cpu_batch(fixpt_t loadfac, fixpt_t estcpu, unsigned int n) 286 { 287 288 if ((n << FSHIFT) >= 7 * loadfac) { 289 return 0; 290 } 291 292 while (estcpu != 0 && n > 1) { 293 estcpu = decay_cpu(loadfac, estcpu); 294 n--; 295 } 296 297 return estcpu; 298 } 299 300 /* 301 * sched_pstats_hook: 302 * 303 * Periodically called from sched_pstats(); used to recalculate priorities. 304 */ 305 void 306 sched_pstats_hook(struct lwp *l) 307 { 308 fixpt_t loadfac; 309 int sleeptm; 310 311 /* 312 * If the LWP has slept an entire second, stop recalculating 313 * its priority until it wakes up. 314 */ 315 if (l->l_stat == LSSLEEP || l->l_stat == LSSTOP || 316 l->l_stat == LSSUSPENDED) { 317 l->l_slptime++; 318 sleeptm = 1; 319 } else { 320 sleeptm = 0x7fffffff; 321 } 322 323 if (l->l_slptime <= sleeptm) { 324 loadfac = 2 * (averunnable.ldavg[0]); 325 l->l_estcpu = decay_cpu(loadfac, l->l_estcpu); 326 resetpriority(l); 327 } 328 } 329 330 /* 331 * Recalculate the priority of a process after it has slept for a while. 332 */ 333 static void 334 updatepri(struct lwp *l) 335 { 336 fixpt_t loadfac; 337 338 KASSERT(lwp_locked(l, NULL)); 339 KASSERT(l->l_slptime > 1); 340 341 loadfac = loadfactor(averunnable.ldavg[0]); 342 343 l->l_slptime--; /* the first time was done in sched_pstats */ 344 l->l_estcpu = decay_cpu_batch(loadfac, l->l_estcpu, l->l_slptime); 345 resetpriority(l); 346 } 347 348 static void 349 runqueue_init(runqueue_t *rq) 350 { 351 int i; 352 353 for (i = 0; i < NUM_Q; i++) 354 TAILQ_INIT(&rq->rq_queue[i]); 355 for (i = 0; i < NUM_B; i++) 356 rq->rq_bitmap[i] = 0; 357 TAILQ_INIT(&rq->rq_fixedpri); 358 rq->rq_count = 0; 359 } 360 361 static void 362 runqueue_enqueue(runqueue_t *rq, struct lwp *l) 363 { 364 pri_t pri; 365 lwp_t *l2; 366 367 KASSERT(lwp_locked(l, l->l_cpu->ci_schedstate.spc_mutex)); 368 369 pri = lwp_eprio(l); 370 rq->rq_count++; 371 372 if (pri >= PRI_KTHREAD) { 373 TAILQ_FOREACH(l2, &rq->rq_fixedpri, l_runq) { 374 if (lwp_eprio(l2) < pri) { 375 TAILQ_INSERT_BEFORE(l2, l, l_runq); 376 return; 377 } 378 } 379 TAILQ_INSERT_TAIL(&rq->rq_fixedpri, l, l_runq); 380 return; 381 } 382 383 rq->rq_bitmap[pri >> PPB_SHIFT] |= 384 (0x80000000U >> (pri & PPB_MASK)); 385 TAILQ_INSERT_TAIL(&rq->rq_queue[pri], l, l_runq); 386 } 387 388 static void 389 runqueue_dequeue(runqueue_t *rq, struct lwp *l) 390 { 391 pri_t pri; 392 393 KASSERT(lwp_locked(l, l->l_cpu->ci_schedstate.spc_mutex)); 394 395 pri = lwp_eprio(l); 396 rq->rq_count--; 397 398 if (pri >= PRI_KTHREAD) { 399 TAILQ_REMOVE(&rq->rq_fixedpri, l, l_runq); 400 return; 401 } 402 403 TAILQ_REMOVE(&rq->rq_queue[pri], l, l_runq); 404 if (TAILQ_EMPTY(&rq->rq_queue[pri])) 405 rq->rq_bitmap[pri >> PPB_SHIFT] ^= 406 (0x80000000U >> (pri & PPB_MASK)); 407 } 408 409 #if (NUM_B != 3) || (NUM_Q != 96) 410 #error adjust runqueue_nextlwp 411 #endif 412 413 static struct lwp * 414 runqueue_nextlwp(runqueue_t *rq) 415 { 416 pri_t pri; 417 418 KASSERT(rq->rq_count != 0); 419 420 if (!TAILQ_EMPTY(&rq->rq_fixedpri)) 421 return TAILQ_FIRST(&rq->rq_fixedpri); 422 423 if (rq->rq_bitmap[2] != 0) 424 pri = 96 - ffs(rq->rq_bitmap[2]); 425 else if (rq->rq_bitmap[1] != 0) 426 pri = 64 - ffs(rq->rq_bitmap[1]); 427 else 428 pri = 32 - ffs(rq->rq_bitmap[0]); 429 return TAILQ_FIRST(&rq->rq_queue[pri]); 430 } 431 432 #if defined(DDB) 433 static void 434 runqueue_print(const runqueue_t *rq, void (*pr)(const char *, ...)) 435 { 436 CPU_INFO_ITERATOR cii; 437 struct cpu_info *ci; 438 lwp_t *l; 439 int i; 440 441 printf("PID\tLID\tPRI\tIPRI\tEPRI\tLWP\t\t NAME\n"); 442 443 TAILQ_FOREACH(l, &rq->rq_fixedpri, l_runq) { 444 (*pr)("%d\t%d\%d\t%d\t%d\t%016lx %s\n", 445 l->l_proc->p_pid, l->l_lid, (int)l->l_priority, 446 (int)l->l_inheritedprio, lwp_eprio(l), 447 (long)l, l->l_proc->p_comm); 448 } 449 450 for (i = NUM_Q - 1; i >= 0; i--) { 451 TAILQ_FOREACH(l, &rq->rq_queue[i], l_runq) { 452 (*pr)("%d\t%d\t%d\t%d\t%d\t%016lx %s\n", 453 l->l_proc->p_pid, l->l_lid, (int)l->l_priority, 454 (int)l->l_inheritedprio, lwp_eprio(l), 455 (long)l, l->l_proc->p_comm); 456 } 457 } 458 459 printf("CPUIDX\tRESCHED\tCURPRI\tFLAGS\n"); 460 for (CPU_INFO_FOREACH(cii, ci)) { 461 printf("%d\t%d\t%d\t%04x\n", (int)ci->ci_index, 462 (int)ci->ci_want_resched, 463 (int)ci->ci_schedstate.spc_curpriority, 464 (int)ci->ci_schedstate.spc_flags); 465 } 466 467 printf("NEXTLWP\n%016lx\n", (long)sched_nextlwp()); 468 } 469 #endif /* defined(DDB) */ 470 471 /* 472 * Initialize the (doubly-linked) run queues 473 * to be empty. 474 */ 475 void 476 sched_rqinit() 477 { 478 479 runqueue_init(&global_queue); 480 mutex_init(&runqueue_lock, MUTEX_DEFAULT, IPL_SCHED); 481 /* Initialize the lock pointer for lwp0 */ 482 lwp0.l_mutex = &curcpu()->ci_schedstate.spc_lwplock; 483 } 484 485 void 486 sched_cpuattach(struct cpu_info *ci) 487 { 488 runqueue_t *rq; 489 490 ci->ci_schedstate.spc_mutex = &runqueue_lock; 491 rq = kmem_zalloc(sizeof(*rq), KM_NOSLEEP); 492 runqueue_init(rq); 493 ci->ci_schedstate.spc_sched_info = rq; 494 } 495 496 void 497 sched_setup() 498 { 499 500 rrticks = hz / 10; 501 } 502 503 void 504 sched_setrunnable(struct lwp *l) 505 { 506 507 if (l->l_slptime > 1) 508 updatepri(l); 509 } 510 511 bool 512 sched_curcpu_runnable_p(void) 513 { 514 struct schedstate_percpu *spc; 515 struct cpu_info *ci; 516 int bits; 517 518 ci = curcpu(); 519 spc = &ci->ci_schedstate; 520 #ifndef __HAVE_FAST_SOFTINTS 521 bits = ci->ci_data.cpu_softints; 522 bits |= ((runqueue_t *)spc->spc_sched_info)->rq_count; 523 #else 524 bits = ((runqueue_t *)spc->spc_sched_info)->rq_count; 525 #endif 526 if (__predict_true((spc->spc_flags & SPCF_OFFLINE) == 0)) 527 bits |= global_queue.rq_count; 528 return bits != 0; 529 } 530 531 void 532 sched_nice(struct proc *p, int n) 533 { 534 struct lwp *l; 535 536 KASSERT(mutex_owned(&p->p_smutex)); 537 538 p->p_nice = n; 539 LIST_FOREACH(l, &p->p_lwps, l_sibling) { 540 lwp_lock(l); 541 resetpriority(l); 542 lwp_unlock(l); 543 } 544 } 545 546 /* 547 * Recompute the priority of an LWP. Arrange to reschedule if 548 * the resulting priority is better than that of the current LWP. 549 */ 550 static void 551 resetpriority(struct lwp *l) 552 { 553 pri_t pri; 554 struct proc *p = l->l_proc; 555 556 KASSERT(lwp_locked(l, NULL)); 557 558 if (l->l_class != SCHED_OTHER) 559 return; 560 561 /* See comments above ESTCPU_SHIFT definition. */ 562 pri = (PRI_KERNEL - 1) - (l->l_estcpu >> ESTCPU_SHIFT) - p->p_nice; 563 pri = imax(pri, 0); 564 if (pri != l->l_priority) 565 lwp_changepri(l, pri); 566 } 567 568 /* 569 * We adjust the priority of the current process. The priority of a process 570 * gets worse as it accumulates CPU time. The CPU usage estimator (l_estcpu) 571 * is increased here. The formula for computing priorities (in kern_synch.c) 572 * will compute a different value each time l_estcpu increases. This can 573 * cause a switch, but unless the priority crosses a PPQ boundary the actual 574 * queue will not change. The CPU usage estimator ramps up quite quickly 575 * when the process is running (linearly), and decays away exponentially, at 576 * a rate which is proportionally slower when the system is busy. The basic 577 * principle is that the system will 90% forget that the process used a lot 578 * of CPU time in 5 * loadav seconds. This causes the system to favor 579 * processes which haven't run much recently, and to round-robin among other 580 * processes. 581 */ 582 583 void 584 sched_schedclock(struct lwp *l) 585 { 586 587 if (l->l_class != SCHED_OTHER) 588 return; 589 590 KASSERT(!CURCPU_IDLE_P()); 591 l->l_estcpu = ESTCPULIM(l->l_estcpu + ESTCPU_ACCUM); 592 lwp_lock(l); 593 resetpriority(l); 594 lwp_unlock(l); 595 } 596 597 /* 598 * sched_proc_fork: 599 * 600 * Inherit the parent's scheduler history. 601 */ 602 void 603 sched_proc_fork(struct proc *parent, struct proc *child) 604 { 605 lwp_t *pl; 606 607 KASSERT(mutex_owned(&parent->p_smutex)); 608 609 pl = LIST_FIRST(&parent->p_lwps); 610 child->p_estcpu_inherited = pl->l_estcpu; 611 child->p_forktime = sched_pstats_ticks; 612 } 613 614 /* 615 * sched_proc_exit: 616 * 617 * Chargeback parents for the sins of their children. 618 */ 619 void 620 sched_proc_exit(struct proc *parent, struct proc *child) 621 { 622 fixpt_t loadfac = loadfactor(averunnable.ldavg[0]); 623 fixpt_t estcpu; 624 lwp_t *pl, *cl; 625 626 /* XXX Only if parent != init?? */ 627 628 mutex_enter(&parent->p_smutex); 629 pl = LIST_FIRST(&parent->p_lwps); 630 cl = LIST_FIRST(&child->p_lwps); 631 estcpu = decay_cpu_batch(loadfac, child->p_estcpu_inherited, 632 sched_pstats_ticks - child->p_forktime); 633 if (cl->l_estcpu > estcpu) { 634 lwp_lock(pl); 635 pl->l_estcpu = ESTCPULIM(pl->l_estcpu + cl->l_estcpu - estcpu); 636 lwp_unlock(pl); 637 } 638 mutex_exit(&parent->p_smutex); 639 } 640 641 void 642 sched_enqueue(struct lwp *l, bool ctxswitch) 643 { 644 645 if ((l->l_flag & LW_BOUND) != 0) 646 runqueue_enqueue(l->l_cpu->ci_schedstate.spc_sched_info, l); 647 else 648 runqueue_enqueue(&global_queue, l); 649 } 650 651 /* 652 * XXXSMP When LWP dispatch (cpu_switch()) is changed to use sched_dequeue(), 653 * drop of the effective priority level from kernel to user needs to be 654 * moved here from userret(). The assignment in userret() is currently 655 * done unlocked. 656 */ 657 void 658 sched_dequeue(struct lwp *l) 659 { 660 661 if ((l->l_flag & LW_BOUND) != 0) 662 runqueue_dequeue(l->l_cpu->ci_schedstate.spc_sched_info, l); 663 else 664 runqueue_dequeue(&global_queue, l); 665 } 666 667 struct lwp * 668 sched_nextlwp(void) 669 { 670 struct schedstate_percpu *spc; 671 runqueue_t *rq; 672 lwp_t *l1, *l2; 673 674 spc = &curcpu()->ci_schedstate; 675 676 /* For now, just pick the highest priority LWP. */ 677 rq = spc->spc_sched_info; 678 l1 = NULL; 679 if (rq->rq_count != 0) 680 l1 = runqueue_nextlwp(rq); 681 682 rq = &global_queue; 683 if (__predict_false((spc->spc_flags & SPCF_OFFLINE) != 0) || 684 rq->rq_count == 0) 685 return l1; 686 l2 = runqueue_nextlwp(rq); 687 688 if (l1 == NULL) 689 return l2; 690 if (l2 == NULL) 691 return l1; 692 if (lwp_eprio(l2) > lwp_eprio(l1)) 693 return l2; 694 else 695 return l1; 696 } 697 698 struct cpu_info * 699 sched_takecpu(struct lwp *l) 700 { 701 702 return l->l_cpu; 703 } 704 705 void 706 sched_wakeup(struct lwp *l) 707 { 708 709 } 710 711 void 712 sched_slept(struct lwp *l) 713 { 714 715 } 716 717 void 718 sched_lwp_fork(struct lwp *l1, struct lwp *l2) 719 { 720 721 l2->l_estcpu = l1->l_estcpu; 722 } 723 724 void 725 sched_lwp_exit(struct lwp *l) 726 { 727 728 } 729 730 void 731 sched_lwp_collect(struct lwp *t) 732 { 733 lwp_t *l; 734 735 /* Absorb estcpu value of collected LWP. */ 736 l = curlwp; 737 lwp_lock(l); 738 l->l_estcpu += t->l_estcpu; 739 lwp_unlock(l); 740 } 741 742 /* 743 * sysctl setup. XXX This should be split with kern_synch.c. 744 */ 745 SYSCTL_SETUP(sysctl_sched_setup, "sysctl kern.sched subtree setup") 746 { 747 const struct sysctlnode *node = NULL; 748 749 sysctl_createv(clog, 0, NULL, NULL, 750 CTLFLAG_PERMANENT, 751 CTLTYPE_NODE, "kern", NULL, 752 NULL, 0, NULL, 0, 753 CTL_KERN, CTL_EOL); 754 sysctl_createv(clog, 0, NULL, &node, 755 CTLFLAG_PERMANENT, 756 CTLTYPE_NODE, "sched", 757 SYSCTL_DESCR("Scheduler options"), 758 NULL, 0, NULL, 0, 759 CTL_KERN, CTL_CREATE, CTL_EOL); 760 761 KASSERT(node != NULL); 762 763 sysctl_createv(clog, 0, &node, NULL, 764 CTLFLAG_PERMANENT, 765 CTLTYPE_STRING, "name", NULL, 766 NULL, 0, __UNCONST("4.4BSD"), 0, 767 CTL_CREATE, CTL_EOL); 768 sysctl_createv(clog, 0, &node, NULL, 769 CTLFLAG_READWRITE, 770 CTLTYPE_INT, "timesoftints", 771 SYSCTL_DESCR("Track CPU time for soft interrupts"), 772 NULL, 0, &softint_timing, 0, 773 CTL_CREATE, CTL_EOL); 774 } 775 776 #if defined(DDB) 777 void 778 sched_print_runqueue(void (*pr)(const char *, ...)) 779 { 780 781 runqueue_print(&global_queue, pr); 782 } 783 #endif /* defined(DDB) */ 784