sys_pset.c revision 1.8
1 /* $NetBSD: sys_pset.c,v 1.8 2008/06/22 12:59:18 ad 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 * Implementation of the Processor Sets. 31 * 32 * Locking 33 * The array of the processor-set structures and its members are protected 34 * by the global cpu_lock. Note that in scheduler, the very l_psid value 35 * might be used without lock held. 36 */ 37 38 #include <sys/cdefs.h> 39 __KERNEL_RCSID(0, "$NetBSD: sys_pset.c,v 1.8 2008/06/22 12:59:18 ad Exp $"); 40 41 #include <sys/param.h> 42 43 #include <sys/cpu.h> 44 #include <sys/kauth.h> 45 #include <sys/kmem.h> 46 #include <sys/lwp.h> 47 #include <sys/mutex.h> 48 #include <sys/proc.h> 49 #include <sys/pset.h> 50 #include <sys/sched.h> 51 #include <sys/syscallargs.h> 52 #include <sys/sysctl.h> 53 #include <sys/systm.h> 54 #include <sys/types.h> 55 56 static pset_info_t ** psets; 57 static u_int psets_max; 58 static u_int psets_count; 59 60 static int psets_realloc(int); 61 static int psid_validate(psetid_t, bool); 62 static int kern_pset_create(psetid_t *); 63 static int kern_pset_destroy(psetid_t); 64 65 /* 66 * Initialization of the processor-sets. 67 */ 68 void 69 psets_init(void) 70 { 71 72 psets_max = max(MAXCPUS, 32); 73 psets = kmem_zalloc(psets_max * sizeof(void *), KM_SLEEP); 74 psets_count = 0; 75 } 76 77 /* 78 * Reallocate the array of the processor-set structures. 79 */ 80 static int 81 psets_realloc(int new_psets_max) 82 { 83 pset_info_t **new_psets, **old_psets; 84 const u_int newsize = new_psets_max * sizeof(void *); 85 u_int i, oldsize; 86 87 if (new_psets_max < 1) 88 return EINVAL; 89 90 new_psets = kmem_zalloc(newsize, KM_SLEEP); 91 mutex_enter(&cpu_lock); 92 old_psets = psets; 93 oldsize = psets_max * sizeof(void *); 94 95 /* Check if we can lower the size of the array */ 96 if (new_psets_max < psets_max) { 97 for (i = new_psets_max; i < psets_max; i++) { 98 if (psets[i] == NULL) 99 continue; 100 mutex_exit(&cpu_lock); 101 kmem_free(new_psets, newsize); 102 return EBUSY; 103 } 104 } 105 106 /* Copy all pointers to the new array */ 107 memcpy(new_psets, psets, newsize); 108 psets_max = new_psets_max; 109 psets = new_psets; 110 mutex_exit(&cpu_lock); 111 112 kmem_free(old_psets, oldsize); 113 return 0; 114 } 115 116 /* 117 * Validate processor-set ID. 118 */ 119 static int 120 psid_validate(psetid_t psid, bool chkps) 121 { 122 123 KASSERT(mutex_owned(&cpu_lock)); 124 125 if (chkps && (psid == PS_NONE || psid == PS_QUERY || psid == PS_MYID)) 126 return 0; 127 if (psid <= 0 || psid > psets_max) 128 return EINVAL; 129 if (psets[psid - 1] == NULL) 130 return EINVAL; 131 if (psets[psid - 1]->ps_flags & PSET_BUSY) 132 return EBUSY; 133 134 return 0; 135 } 136 137 /* 138 * Create a processor-set. 139 */ 140 static int 141 kern_pset_create(psetid_t *psid) 142 { 143 pset_info_t *pi; 144 u_int i; 145 146 if (psets_count == psets_max) 147 return ENOMEM; 148 149 pi = kmem_zalloc(sizeof(pset_info_t), KM_SLEEP); 150 151 mutex_enter(&cpu_lock); 152 if (psets_count == psets_max) { 153 mutex_exit(&cpu_lock); 154 kmem_free(pi, sizeof(pset_info_t)); 155 return ENOMEM; 156 } 157 158 /* Find a free entry in the array */ 159 for (i = 0; i < psets_max; i++) 160 if (psets[i] == NULL) 161 break; 162 KASSERT(i != psets_max); 163 164 psets[i] = pi; 165 psets_count++; 166 mutex_exit(&cpu_lock); 167 168 *psid = i + 1; 169 return 0; 170 } 171 172 /* 173 * Destroy a processor-set. 174 */ 175 static int 176 kern_pset_destroy(psetid_t psid) 177 { 178 struct cpu_info *ci; 179 pset_info_t *pi; 180 struct lwp *l; 181 CPU_INFO_ITERATOR cii; 182 int error; 183 184 mutex_enter(&cpu_lock); 185 if (psid == PS_MYID) { 186 /* Use caller's processor-set ID */ 187 psid = curlwp->l_psid; 188 } 189 error = psid_validate(psid, false); 190 if (error) { 191 mutex_exit(&cpu_lock); 192 return error; 193 } 194 195 /* Release the processor-set from all CPUs */ 196 for (CPU_INFO_FOREACH(cii, ci)) { 197 struct schedstate_percpu *spc; 198 199 spc = &ci->ci_schedstate; 200 if (spc->spc_psid != psid) 201 continue; 202 spc->spc_psid = PS_NONE; 203 } 204 /* Mark that processor-set is going to be destroyed */ 205 pi = psets[psid - 1]; 206 pi->ps_flags |= PSET_BUSY; 207 mutex_exit(&cpu_lock); 208 209 /* Unmark the processor-set ID from each thread */ 210 mutex_enter(proc_lock); 211 LIST_FOREACH(l, &alllwp, l_list) { 212 /* Safe to check and set without lock held */ 213 if (l->l_psid != psid) 214 continue; 215 l->l_psid = PS_NONE; 216 } 217 mutex_exit(proc_lock); 218 219 /* Destroy the processor-set */ 220 mutex_enter(&cpu_lock); 221 psets[psid - 1] = NULL; 222 psets_count--; 223 mutex_exit(&cpu_lock); 224 225 kmem_free(pi, sizeof(pset_info_t)); 226 return 0; 227 } 228 229 /* 230 * General system calls for the processor-sets. 231 */ 232 233 int 234 sys_pset_create(struct lwp *l, const struct sys_pset_create_args *uap, 235 register_t *retval) 236 { 237 /* { 238 syscallarg(psetid_t) *psid; 239 } */ 240 psetid_t psid; 241 int error; 242 243 /* Available only for super-user */ 244 if (kauth_authorize_system(l->l_cred, KAUTH_SYSTEM_PSET, 245 KAUTH_REQ_SYSTEM_PSET_CREATE, NULL, NULL, NULL)) 246 return EPERM; 247 248 error = kern_pset_create(&psid); 249 if (error) 250 return error; 251 252 error = copyout(&psid, SCARG(uap, psid), sizeof(psetid_t)); 253 if (error) 254 (void)kern_pset_destroy(psid); 255 256 return error; 257 } 258 259 int 260 sys_pset_destroy(struct lwp *l, const struct sys_pset_destroy_args *uap, 261 register_t *retval) 262 { 263 /* { 264 syscallarg(psetid_t) psid; 265 } */ 266 267 /* Available only for super-user */ 268 if (kauth_authorize_system(l->l_cred, KAUTH_SYSTEM_PSET, 269 KAUTH_REQ_SYSTEM_PSET_DESTROY, 270 KAUTH_ARG(SCARG(uap, psid)), NULL, NULL)) 271 return EPERM; 272 273 return kern_pset_destroy(SCARG(uap, psid)); 274 } 275 276 int 277 sys_pset_assign(struct lwp *l, const struct sys_pset_assign_args *uap, 278 register_t *retval) 279 { 280 /* { 281 syscallarg(psetid_t) psid; 282 syscallarg(cpuid_t) cpuid; 283 syscallarg(psetid_t) *opsid; 284 } */ 285 struct cpu_info *ci; 286 struct schedstate_percpu *spc; 287 psetid_t psid = SCARG(uap, psid), opsid = 0; 288 CPU_INFO_ITERATOR cii; 289 int error = 0, nnone; 290 291 /* Available only for super-user, except the case of PS_QUERY */ 292 if (kauth_authorize_system(l->l_cred, KAUTH_SYSTEM_PSET, 293 KAUTH_REQ_SYSTEM_PSET_ASSIGN, KAUTH_ARG(SCARG(uap, psid)), NULL, 294 NULL)) 295 return EPERM; 296 297 /* Find the target CPU */ 298 mutex_enter(&cpu_lock); 299 spc = NULL; 300 nnone = 0; 301 for (CPU_INFO_FOREACH(cii, ci)) { 302 if (cpu_index(ci) == SCARG(uap, cpuid)) 303 spc = &ci->ci_schedstate; 304 nnone += (ci->ci_schedstate.spc_psid == PS_NONE); 305 } 306 if (spc == NULL) { 307 mutex_exit(&cpu_lock); 308 return EINVAL; 309 } 310 error = psid_validate(psid, true); 311 if (error) { 312 mutex_exit(&cpu_lock); 313 return error; 314 } 315 opsid = spc->spc_psid; 316 switch (psid) { 317 case PS_QUERY: 318 break; 319 case PS_MYID: 320 psid = curlwp->l_psid; 321 /* FALLTHROUGH */ 322 default: 323 /* Ensure at least one CPU stays in the default set. */ 324 if (nnone == 1 && spc->spc_psid == PS_NONE && 325 psid != PS_NONE) { 326 mutex_exit(&cpu_lock); 327 return EBUSY; 328 } 329 spc->spc_psid = psid; 330 break; 331 } 332 mutex_exit(&cpu_lock); 333 334 if (SCARG(uap, opsid) != NULL) 335 error = copyout(&opsid, SCARG(uap, opsid), sizeof(psetid_t)); 336 337 return error; 338 } 339 340 int 341 sys__pset_bind(struct lwp *l, const struct sys__pset_bind_args *uap, 342 register_t *retval) 343 { 344 /* { 345 syscallarg(idtype_t) idtype; 346 syscallarg(id_t) first_id; 347 syscallarg(id_t) second_id; 348 syscallarg(psetid_t) psid; 349 syscallarg(psetid_t) *opsid; 350 } */ 351 struct cpu_info *ci; 352 struct proc *p; 353 struct lwp *t; 354 id_t id1, id2; 355 pid_t pid = 0; 356 lwpid_t lid = 0; 357 psetid_t psid, opsid; 358 int error = 0, lcnt; 359 360 psid = SCARG(uap, psid); 361 362 /* Available only for super-user, except the case of PS_QUERY */ 363 if (kauth_authorize_system(l->l_cred, KAUTH_SYSTEM_PSET, 364 KAUTH_REQ_SYSTEM_PSET_BIND, KAUTH_ARG(SCARG(uap, psid)), NULL, 365 NULL)) 366 return EPERM; 367 368 mutex_enter(&cpu_lock); 369 error = psid_validate(psid, true); 370 if (error) { 371 mutex_exit(&cpu_lock); 372 return error; 373 } 374 if (psid == PS_MYID) 375 psid = curlwp->l_psid; 376 if (psid != PS_QUERY && psid != PS_NONE) 377 psets[psid - 1]->ps_flags |= PSET_BUSY; 378 mutex_exit(&cpu_lock); 379 380 /* 381 * Get PID and LID from the ID. 382 */ 383 p = l->l_proc; 384 id1 = SCARG(uap, first_id); 385 id2 = SCARG(uap, second_id); 386 387 switch (SCARG(uap, idtype)) { 388 case P_PID: 389 /* 390 * Process: 391 * First ID - PID; 392 * Second ID - ignored; 393 */ 394 pid = (id1 == P_MYID) ? p->p_pid : id1; 395 lid = 0; 396 break; 397 case P_LWPID: 398 /* 399 * Thread (LWP): 400 * First ID - LID; 401 * Second ID - PID; 402 */ 403 if (id1 == P_MYID) { 404 pid = p->p_pid; 405 lid = l->l_lid; 406 break; 407 } 408 lid = id1; 409 pid = (id2 == P_MYID) ? p->p_pid : id2; 410 break; 411 default: 412 error = EINVAL; 413 goto error; 414 } 415 416 /* Find the process */ 417 mutex_enter(proc_lock); 418 p = p_find(pid, PFIND_LOCKED); 419 if (p == NULL) { 420 mutex_exit(proc_lock); 421 error = ESRCH; 422 goto error; 423 } 424 mutex_enter(p->p_lock); 425 mutex_exit(proc_lock); 426 427 /* Disallow modification of the system processes */ 428 if (p->p_flag & PK_SYSTEM) { 429 mutex_exit(p->p_lock); 430 error = EPERM; 431 goto error; 432 } 433 434 /* Find the LWP(s) */ 435 lcnt = 0; 436 ci = NULL; 437 LIST_FOREACH(t, &p->p_lwps, l_sibling) { 438 if (lid && lid != t->l_lid) 439 continue; 440 /* 441 * Bind the thread to the processor-set, 442 * take some CPU and migrate. 443 */ 444 lwp_lock(t); 445 opsid = t->l_psid; 446 t->l_psid = psid; 447 ci = sched_takecpu(l); 448 /* Unlocks LWP */ 449 lwp_migrate(t, ci); 450 lcnt++; 451 } 452 mutex_exit(p->p_lock); 453 if (lcnt == 0) { 454 error = ESRCH; 455 goto error; 456 } 457 if (SCARG(uap, opsid)) 458 error = copyout(&opsid, SCARG(uap, opsid), sizeof(psetid_t)); 459 error: 460 if (psid != PS_QUERY && psid != PS_NONE) { 461 mutex_enter(&cpu_lock); 462 psets[psid - 1]->ps_flags &= ~PSET_BUSY; 463 mutex_exit(&cpu_lock); 464 } 465 return error; 466 } 467 468 /* 469 * Sysctl nodes and initialization. 470 */ 471 472 static int 473 sysctl_psets_max(SYSCTLFN_ARGS) 474 { 475 struct sysctlnode node; 476 int error, newsize; 477 478 node = *rnode; 479 node.sysctl_data = &newsize; 480 481 newsize = psets_max; 482 error = sysctl_lookup(SYSCTLFN_CALL(&node)); 483 if (error || newp == NULL) 484 return error; 485 486 if (newsize <= 0) 487 return EINVAL; 488 489 sysctl_unlock(); 490 error = psets_realloc(newsize); 491 sysctl_relock(); 492 return error; 493 } 494 495 static int 496 sysctl_psets_list(SYSCTLFN_ARGS) 497 { 498 const size_t bufsz = 1024; 499 char *buf, tbuf[16]; 500 int i, error; 501 size_t len; 502 503 sysctl_unlock(); 504 buf = kmem_alloc(bufsz, KM_SLEEP); 505 snprintf(buf, bufsz, "%d:1", PS_NONE); /* XXX */ 506 507 mutex_enter(&cpu_lock); 508 for (i = 0; i < psets_max; i++) { 509 if (psets[i] == NULL) 510 continue; 511 snprintf(tbuf, sizeof(tbuf), ",%d:2", i + 1); /* XXX */ 512 strlcat(buf, tbuf, bufsz); 513 } 514 mutex_exit(&cpu_lock); 515 len = strlen(buf) + 1; 516 error = 0; 517 if (oldp != NULL) 518 error = copyout(buf, oldp, min(len, *oldlenp)); 519 *oldlenp = len; 520 kmem_free(buf, bufsz); 521 sysctl_relock(); 522 return error; 523 } 524 525 SYSCTL_SETUP(sysctl_pset_setup, "sysctl kern.pset subtree setup") 526 { 527 const struct sysctlnode *node = NULL; 528 529 sysctl_createv(clog, 0, NULL, NULL, 530 CTLFLAG_PERMANENT, 531 CTLTYPE_NODE, "kern", NULL, 532 NULL, 0, NULL, 0, 533 CTL_KERN, CTL_EOL); 534 sysctl_createv(clog, 0, NULL, &node, 535 CTLFLAG_PERMANENT, 536 CTLTYPE_NODE, "pset", 537 SYSCTL_DESCR("Processor-set options"), 538 NULL, 0, NULL, 0, 539 CTL_KERN, CTL_CREATE, CTL_EOL); 540 541 if (node == NULL) 542 return; 543 544 sysctl_createv(clog, 0, &node, NULL, 545 CTLFLAG_PERMANENT | CTLFLAG_READWRITE, 546 CTLTYPE_INT, "psets_max", 547 SYSCTL_DESCR("Maximal count of the processor-sets"), 548 sysctl_psets_max, 0, &psets_max, 0, 549 CTL_CREATE, CTL_EOL); 550 sysctl_createv(clog, 0, &node, NULL, 551 CTLFLAG_PERMANENT, 552 CTLTYPE_STRING, "list", 553 SYSCTL_DESCR("List of active sets"), 554 sysctl_psets_list, 0, NULL, 0, 555 CTL_CREATE, CTL_EOL); 556 } 557
Indexes created Tue Sep 23 22:09:46 GMT 2025