sys_sched.c revision 1.23
1 /* $NetBSD: sys_sched.c,v 1.23 2008/06/15 20:32:57 christos Exp $ */ 2 3 /* 4 * Copyright (c) 2008, Mindaugas Rasiukevicius <rmind at NetBSD org> 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 /* 30 * System calls relating to the scheduler. 31 * 32 * TODO: 33 * - Handle pthread_setschedprio() as defined by POSIX; 34 * - Handle sched_yield() case for SCHED_FIFO as defined by POSIX; 35 */ 36 37 #include <sys/cdefs.h> 38 __KERNEL_RCSID(0, "$NetBSD: sys_sched.c,v 1.23 2008/06/15 20:32:57 christos Exp $"); 39 40 #include <sys/param.h> 41 42 #include <sys/cpu.h> 43 #include <sys/kauth.h> 44 #include <sys/kmem.h> 45 #include <sys/lwp.h> 46 #include <sys/mutex.h> 47 #include <sys/proc.h> 48 #include <sys/pset.h> 49 #include <sys/sched.h> 50 #include <sys/syscallargs.h> 51 #include <sys/sysctl.h> 52 #include <sys/systm.h> 53 #include <sys/types.h> 54 #include <sys/unistd.h> 55 56 /* 57 * Convert user priority or the in-kernel priority or convert the current 58 * priority to the appropriate range according to the policy change. 59 */ 60 static pri_t 61 convert_pri(lwp_t *l, int policy, pri_t pri) 62 { 63 int delta = 0; 64 65 switch (policy) { 66 case SCHED_OTHER: 67 delta = PRI_USER; 68 break; 69 case SCHED_FIFO: 70 case SCHED_RR: 71 delta = PRI_USER_RT; 72 break; 73 default: 74 panic("upri_to_kpri"); 75 } 76 77 if (pri != PRI_NONE) { 78 /* Convert user priority to the in-kernel */ 79 KASSERT(pri >= SCHED_PRI_MIN && pri <= SCHED_PRI_MAX); 80 return pri + delta; 81 } 82 if (l->l_class == policy) 83 return l->l_priority; 84 85 /* Change the current priority to the appropriate range */ 86 if (l->l_class == SCHED_OTHER) { 87 KASSERT(policy == SCHED_FIFO || policy == SCHED_RR); 88 return delta; 89 } 90 if (policy == SCHED_OTHER) { 91 KASSERT(l->l_class == SCHED_FIFO || l->l_class == SCHED_RR); 92 return l->l_priority - delta; 93 } 94 KASSERT(l->l_class != SCHED_OTHER && policy != SCHED_OTHER); 95 return l->l_class; 96 } 97 98 int 99 do_sched_setparam(pid_t pid, lwpid_t lid, int policy, 100 const struct sched_param *params) 101 { 102 struct proc *p; 103 struct lwp *t; 104 pri_t pri; 105 u_int lcnt; 106 int error; 107 108 error = 0; 109 110 pri = params->sched_priority; 111 112 /* If no parameters specified, just return (this should not happen) */ 113 if (pri == PRI_NONE && policy == SCHED_NONE) 114 return 0; 115 116 /* Validate scheduling class */ 117 if (policy != SCHED_NONE && (policy < SCHED_OTHER || policy > SCHED_RR)) 118 return EINVAL; 119 120 /* Validate priority */ 121 if (pri != PRI_NONE && (pri < SCHED_PRI_MIN || pri > SCHED_PRI_MAX)) 122 return EINVAL; 123 124 if (pid != 0) { 125 /* Find the process */ 126 mutex_enter(proc_lock); 127 p = p_find(pid, PFIND_LOCKED); 128 if (p == NULL) { 129 mutex_exit(proc_lock); 130 return ESRCH; 131 } 132 mutex_enter(p->p_lock); 133 mutex_exit(proc_lock); 134 /* Disallow modification of system processes */ 135 if ((p->p_flag & PK_SYSTEM) != 0) { 136 mutex_exit(p->p_lock); 137 return EPERM; 138 } 139 } else { 140 /* Use the calling process */ 141 p = curlwp->l_proc; 142 mutex_enter(p->p_lock); 143 } 144 145 /* Find the LWP(s) */ 146 lcnt = 0; 147 LIST_FOREACH(t, &p->p_lwps, l_sibling) { 148 pri_t kpri; 149 int lpolicy; 150 151 if (lid && lid != t->l_lid) 152 continue; 153 lcnt++; 154 KASSERT(pri != PRI_NONE || policy != SCHED_NONE); 155 lwp_lock(t); 156 157 if (policy == SCHED_NONE) 158 lpolicy = t->l_class; 159 else 160 lpolicy = policy; 161 162 /* 163 * Note that, priority may need to be changed to get into 164 * the correct priority range of the new scheduling class. 165 */ 166 kpri = convert_pri(t, lpolicy, pri); 167 168 /* Check the permission */ 169 error = kauth_authorize_process(kauth_cred_get(), 170 KAUTH_PROCESS_SCHEDULER_SETPARAM, p, t, KAUTH_ARG(lpolicy), 171 KAUTH_ARG(kpri)); 172 if (error) { 173 lwp_unlock(t); 174 break; 175 } 176 177 /* Set the scheduling class */ 178 if (policy != SCHED_NONE) 179 t->l_class = policy; 180 181 /* Change the priority */ 182 if (t->l_priority != kpri) 183 lwp_changepri(t, kpri); 184 185 lwp_unlock(t); 186 } 187 mutex_exit(p->p_lock); 188 return (lcnt == 0) ? ESRCH : error; 189 } 190 191 /* 192 * Set scheduling parameters. 193 */ 194 int 195 sys__sched_setparam(struct lwp *l, const struct sys__sched_setparam_args *uap, 196 register_t *retval) 197 { 198 /* { 199 syscallarg(pid_t) pid; 200 syscallarg(lwpid_t) lid; 201 syscallarg(int) policy; 202 syscallarg(const struct sched_param *) params; 203 } */ 204 struct sched_param params; 205 int error; 206 207 /* Get the parameters from the user-space */ 208 error = copyin(SCARG(uap, params), ¶ms, sizeof(params)); 209 if (error) 210 goto out; 211 212 error = do_sched_setparam(SCARG(uap, pid), SCARG(uap, lid), 213 SCARG(uap, policy), ¶ms); 214 215 out: 216 return (error); 217 } 218 219 int 220 do_sched_getparam(pid_t pid, lwpid_t lid, int *policy, 221 struct sched_param *params) 222 { 223 struct sched_param lparams; 224 struct lwp *t; 225 int error, lpolicy; 226 227 /* Locks the LWP */ 228 t = lwp_find2(pid, lid); 229 if (t == NULL) 230 return ESRCH; 231 232 /* Check the permission */ 233 error = kauth_authorize_process(kauth_cred_get(), 234 KAUTH_PROCESS_SCHEDULER_GETPARAM, t->l_proc, NULL, NULL, NULL); 235 if (error != 0) { 236 mutex_exit(t->l_proc->p_lock); 237 return error; 238 } 239 240 lwp_lock(t); 241 lparams.sched_priority = t->l_priority; 242 lpolicy = t->l_class; 243 244 switch (lpolicy) { 245 case SCHED_OTHER: 246 lparams.sched_priority -= PRI_USER; 247 break; 248 case SCHED_RR: 249 case SCHED_FIFO: 250 lparams.sched_priority -= PRI_USER_RT; 251 break; 252 } 253 254 if (policy != NULL) 255 *policy = lpolicy; 256 257 if (params != NULL) 258 *params = lparams; 259 260 lwp_unlock(t); 261 mutex_exit(t->l_proc->p_lock); 262 return error; 263 } 264 265 /* 266 * Get scheduling parameters. 267 */ 268 int 269 sys__sched_getparam(struct lwp *l, const struct sys__sched_getparam_args *uap, 270 register_t *retval) 271 { 272 /* { 273 syscallarg(pid_t) pid; 274 syscallarg(lwpid_t) lid; 275 syscallarg(int *) policy; 276 syscallarg(struct sched_param *) params; 277 } */ 278 struct sched_param params; 279 int error, policy; 280 281 error = do_sched_getparam(SCARG(uap, pid), SCARG(uap, lid), &policy, 282 ¶ms); 283 if (error) 284 goto out; 285 286 error = copyout(¶ms, SCARG(uap, params), sizeof(params)); 287 if (error == 0 && SCARG(uap, policy) != NULL) 288 error = copyout(&policy, SCARG(uap, policy), sizeof(int)); 289 290 out: 291 return (error); 292 } 293 294 /* Allocate the CPU set, and get it from userspace */ 295 static int 296 gencpuset(cpuset_t **dset, const cpuset_t *sset, size_t size) 297 { 298 int error; 299 300 *dset = _cpuset_create(); 301 302 if (size != _cpuset_size(*dset)) 303 goto out; 304 305 error = copyin(sset, *dset, size); 306 if (error) 307 goto out; 308 309 error = EINVAL; 310 if (_cpuset_nused(*dset) != 1) 311 goto out; 312 313 return 0; 314 out: 315 _cpuset_unuse(*dset, NULL); 316 return error; 317 } 318 319 /* 320 * Set affinity. 321 */ 322 int 323 sys__sched_setaffinity(struct lwp *l, 324 const struct sys__sched_setaffinity_args *uap, register_t *retval) 325 { 326 /* { 327 syscallarg(pid_t) pid; 328 syscallarg(lwpid_t) lid; 329 syscallarg(size_t) size; 330 syscallarg(const cpuset_t *) cpuset; 331 } */ 332 cpuset_t *cpuset, *cpulst = NULL; 333 struct cpu_info *ci = NULL; 334 struct proc *p; 335 struct lwp *t; 336 CPU_INFO_ITERATOR cii; 337 lwpid_t lid; 338 u_int lcnt; 339 int error; 340 341 if ((error = gencpuset(&cpuset, SCARG(uap, cpuset), SCARG(uap, size)))) 342 return error; 343 344 /* Look for a CPU in the set */ 345 for (CPU_INFO_FOREACH(cii, ci)) { 346 if ((error = CPU_ISSET(cpu_index(ci), cpuset)) == -1) { 347 error = E2BIG; 348 goto out; 349 } else if (error) 350 break; 351 } 352 353 if (ci == NULL) { 354 /* Empty set */ 355 _cpuset_unuse(cpuset, NULL); 356 cpuset = NULL; 357 } 358 359 if (SCARG(uap, pid) != 0) { 360 /* Find the process */ 361 mutex_enter(proc_lock); 362 p = p_find(SCARG(uap, pid), PFIND_LOCKED); 363 if (p == NULL) { 364 mutex_exit(proc_lock); 365 error = ESRCH; 366 goto out; 367 } 368 mutex_enter(p->p_lock); 369 mutex_exit(proc_lock); 370 /* Disallow modification of system processes. */ 371 if ((p->p_flag & PK_SYSTEM) != 0) { 372 mutex_exit(p->p_lock); 373 error = EPERM; 374 goto out; 375 } 376 } else { 377 /* Use the calling process */ 378 p = l->l_proc; 379 mutex_enter(p->p_lock); 380 } 381 382 /* 383 * Check the permission. 384 */ 385 error = kauth_authorize_process(l->l_cred, 386 KAUTH_PROCESS_SCHEDULER_SETAFFINITY, p, NULL, NULL, NULL); 387 if (error != 0) { 388 mutex_exit(p->p_lock); 389 goto out; 390 } 391 392 /* Find the LWP(s) */ 393 lcnt = 0; 394 lid = SCARG(uap, lid); 395 LIST_FOREACH(t, &p->p_lwps, l_sibling) { 396 if (lid && lid != t->l_lid) 397 continue; 398 lwp_lock(t); 399 if (cpuset) { 400 /* Set the affinity flag and new CPU set */ 401 t->l_flag |= LW_AFFINITY; 402 _cpuset_use(cpuset); 403 if (t->l_affinity != NULL) 404 _cpuset_unuse(t->l_affinity, &cpulst); 405 t->l_affinity = cpuset; 406 /* Migrate to another CPU, unlocks LWP */ 407 lwp_migrate(t, ci); 408 } else { 409 /* Unset the affinity flag */ 410 t->l_flag &= ~LW_AFFINITY; 411 if (t->l_affinity != NULL) 412 _cpuset_unuse(t->l_affinity, &cpulst); 413 t->l_affinity = NULL; 414 lwp_unlock(t); 415 } 416 lcnt++; 417 } 418 mutex_exit(p->p_lock); 419 if (lcnt == 0) 420 error = ESRCH; 421 out: 422 if (cpuset != NULL) 423 _cpuset_unuse(cpuset, &cpulst); 424 _cpuset_destroy(cpulst); 425 return error; 426 } 427 428 /* 429 * Get affinity. 430 */ 431 int 432 sys__sched_getaffinity(struct lwp *l, 433 const struct sys__sched_getaffinity_args *uap, register_t *retval) 434 { 435 /* { 436 syscallarg(pid_t) pid; 437 syscallarg(lwpid_t) lid; 438 syscallarg(size_t) size; 439 syscallarg(cpuset_t *) cpuset; 440 } */ 441 struct lwp *t; 442 cpuset_t *cpuset; 443 int error; 444 445 if ((error = gencpuset(&cpuset, SCARG(uap, cpuset), SCARG(uap, size)))) 446 return error; 447 448 /* Locks the LWP */ 449 t = lwp_find2(SCARG(uap, pid), SCARG(uap, lid)); 450 if (t == NULL) { 451 error = ESRCH; 452 goto out; 453 } 454 /* Check the permission */ 455 if (kauth_authorize_process(l->l_cred, 456 KAUTH_PROCESS_SCHEDULER_GETAFFINITY, t->l_proc, NULL, NULL, NULL)) { 457 mutex_exit(t->l_proc->p_lock); 458 error = EPERM; 459 goto out; 460 } 461 lwp_lock(t); 462 if (t->l_flag & LW_AFFINITY) { 463 KASSERT(t->l_affinity != NULL); 464 _cpuset_copy(cpuset, t->l_affinity); 465 } else 466 _cpuset_zero(cpuset); 467 lwp_unlock(t); 468 mutex_exit(t->l_proc->p_lock); 469 470 error = copyout(cpuset, SCARG(uap, cpuset), _cpuset_size(cpuset)); 471 out: 472 _cpuset_unuse(cpuset, NULL); 473 return error; 474 } 475 476 /* 477 * Yield. 478 */ 479 int 480 sys_sched_yield(struct lwp *l, const void *v, register_t *retval) 481 { 482 483 yield(); 484 return 0; 485 } 486 487 /* 488 * Sysctl nodes and initialization. 489 */ 490 SYSCTL_SETUP(sysctl_sched_setup, "sysctl sched setup") 491 { 492 const struct sysctlnode *node = NULL; 493 494 sysctl_createv(clog, 0, NULL, NULL, 495 CTLFLAG_PERMANENT, 496 CTLTYPE_NODE, "kern", NULL, 497 NULL, 0, NULL, 0, 498 CTL_KERN, CTL_EOL); 499 sysctl_createv(clog, 0, NULL, NULL, 500 CTLFLAG_PERMANENT|CTLFLAG_IMMEDIATE, 501 CTLTYPE_INT, "posix_sched", 502 SYSCTL_DESCR("Version of IEEE Std 1003.1 and its " 503 "Process Scheduling option to which the " 504 "system attempts to conform"), 505 NULL, _POSIX_PRIORITY_SCHEDULING, NULL, 0, 506 CTL_KERN, CTL_CREATE, CTL_EOL); 507 sysctl_createv(clog, 0, NULL, &node, 508 CTLFLAG_PERMANENT, 509 CTLTYPE_NODE, "sched", 510 SYSCTL_DESCR("Scheduler options"), 511 NULL, 0, NULL, 0, 512 CTL_KERN, CTL_CREATE, CTL_EOL); 513 514 if (node == NULL) 515 return; 516 517 sysctl_createv(clog, 0, &node, NULL, 518 CTLFLAG_PERMANENT | CTLFLAG_IMMEDIATE, 519 CTLTYPE_INT, "pri_min", 520 SYSCTL_DESCR("Minimal POSIX real-time priority"), 521 NULL, SCHED_PRI_MIN, NULL, 0, 522 CTL_CREATE, CTL_EOL); 523 sysctl_createv(clog, 0, &node, NULL, 524 CTLFLAG_PERMANENT | CTLFLAG_IMMEDIATE, 525 CTLTYPE_INT, "pri_max", 526 SYSCTL_DESCR("Maximal POSIX real-time priority"), 527 NULL, SCHED_PRI_MAX, NULL, 0, 528 CTL_CREATE, CTL_EOL); 529 } 530
Indexes created Mon Sep 22 13:09:51 GMT 2025