sys_pset.c revision 1.18 1 /* $NetBSD: sys_pset.c,v 1.18 2014/02/25 18:30:11 pooka 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 1.18 2014/02/25 18:30:11 pooka 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 static kauth_listener_t psets_listener;
60
61 static int psets_realloc(int);
62 static int psid_validate(psetid_t, bool);
63 static int kern_pset_create(psetid_t *);
64 static int kern_pset_destroy(psetid_t);
65
66 static int
67 psets_listener_cb(kauth_cred_t cred, kauth_action_t action, void *cookie,
68 void *arg0, void *arg1, void *arg2, void *arg3)
69 {
70 psetid_t id;
71 enum kauth_system_req req;
72 int result;
73
74 result = KAUTH_RESULT_DEFER;
75 req = (enum kauth_system_req)arg0;
76 id = (psetid_t)(unsigned long)arg1;
77
78 if (action != KAUTH_SYSTEM_PSET)
79 return result;
80
81 if ((req == KAUTH_REQ_SYSTEM_PSET_ASSIGN) ||
82 (req == KAUTH_REQ_SYSTEM_PSET_BIND)) {
83 if (id == PS_QUERY)
84 result = KAUTH_RESULT_ALLOW;
85 }
86
87 return result;
88 }
89
90 /*
91 * Initialization of the processor-sets.
92 */
93 void
94 psets_init(void)
95 {
96
97 psets_max = max(maxcpus, 32);
98 psets = kmem_zalloc(psets_max * sizeof(void *), KM_SLEEP);
99 psets_count = 0;
100
101 psets_listener = kauth_listen_scope(KAUTH_SCOPE_SYSTEM,
102 psets_listener_cb, NULL);
103 }
104
105 /*
106 * Reallocate the array of the processor-set structures.
107 */
108 static int
109 psets_realloc(int new_psets_max)
110 {
111 pset_info_t **new_psets, **old_psets;
112 const u_int newsize = new_psets_max * sizeof(void *);
113 u_int i, oldsize;
114
115 if (new_psets_max < 1)
116 return EINVAL;
117
118 new_psets = kmem_zalloc(newsize, KM_SLEEP);
119 mutex_enter(&cpu_lock);
120 old_psets = psets;
121 oldsize = psets_max * sizeof(void *);
122
123 /* Check if we can lower the size of the array */
124 if (new_psets_max < psets_max) {
125 for (i = new_psets_max; i < psets_max; i++) {
126 if (psets[i] == NULL)
127 continue;
128 mutex_exit(&cpu_lock);
129 kmem_free(new_psets, newsize);
130 return EBUSY;
131 }
132 }
133
134 /* Copy all pointers to the new array */
135 memcpy(new_psets, psets, newsize);
136 psets_max = new_psets_max;
137 psets = new_psets;
138 mutex_exit(&cpu_lock);
139
140 kmem_free(old_psets, oldsize);
141 return 0;
142 }
143
144 /*
145 * Validate processor-set ID.
146 */
147 static int
148 psid_validate(psetid_t psid, bool chkps)
149 {
150
151 KASSERT(mutex_owned(&cpu_lock));
152
153 if (chkps && (psid == PS_NONE || psid == PS_QUERY || psid == PS_MYID))
154 return 0;
155 if (psid <= 0 || psid > psets_max)
156 return EINVAL;
157 if (psets[psid - 1] == NULL)
158 return EINVAL;
159 if (psets[psid - 1]->ps_flags & PSET_BUSY)
160 return EBUSY;
161
162 return 0;
163 }
164
165 /*
166 * Create a processor-set.
167 */
168 static int
169 kern_pset_create(psetid_t *psid)
170 {
171 pset_info_t *pi;
172 u_int i;
173
174 if (psets_count == psets_max)
175 return ENOMEM;
176
177 pi = kmem_zalloc(sizeof(pset_info_t), KM_SLEEP);
178
179 mutex_enter(&cpu_lock);
180 if (psets_count == psets_max) {
181 mutex_exit(&cpu_lock);
182 kmem_free(pi, sizeof(pset_info_t));
183 return ENOMEM;
184 }
185
186 /* Find a free entry in the array */
187 for (i = 0; i < psets_max; i++)
188 if (psets[i] == NULL)
189 break;
190 KASSERT(i != psets_max);
191
192 psets[i] = pi;
193 psets_count++;
194 mutex_exit(&cpu_lock);
195
196 *psid = i + 1;
197 return 0;
198 }
199
200 /*
201 * Destroy a processor-set.
202 */
203 static int
204 kern_pset_destroy(psetid_t psid)
205 {
206 struct cpu_info *ci;
207 pset_info_t *pi;
208 struct lwp *l;
209 CPU_INFO_ITERATOR cii;
210 int error;
211
212 mutex_enter(&cpu_lock);
213 if (psid == PS_MYID) {
214 /* Use caller's processor-set ID */
215 psid = curlwp->l_psid;
216 }
217 error = psid_validate(psid, false);
218 if (error) {
219 mutex_exit(&cpu_lock);
220 return error;
221 }
222
223 /* Release the processor-set from all CPUs */
224 for (CPU_INFO_FOREACH(cii, ci)) {
225 struct schedstate_percpu *spc;
226
227 spc = &ci->ci_schedstate;
228 if (spc->spc_psid != psid)
229 continue;
230 spc->spc_psid = PS_NONE;
231 }
232 /* Mark that processor-set is going to be destroyed */
233 pi = psets[psid - 1];
234 pi->ps_flags |= PSET_BUSY;
235 mutex_exit(&cpu_lock);
236
237 /* Unmark the processor-set ID from each thread */
238 mutex_enter(proc_lock);
239 LIST_FOREACH(l, &alllwp, l_list) {
240 /* Safe to check and set without lock held */
241 if (l->l_psid != psid)
242 continue;
243 l->l_psid = PS_NONE;
244 }
245 mutex_exit(proc_lock);
246
247 /* Destroy the processor-set */
248 mutex_enter(&cpu_lock);
249 psets[psid - 1] = NULL;
250 psets_count--;
251 mutex_exit(&cpu_lock);
252
253 kmem_free(pi, sizeof(pset_info_t));
254 return 0;
255 }
256
257 /*
258 * General system calls for the processor-sets.
259 */
260
261 int
262 sys_pset_create(struct lwp *l, const struct sys_pset_create_args *uap,
263 register_t *retval)
264 {
265 /* {
266 syscallarg(psetid_t) *psid;
267 } */
268 psetid_t psid;
269 int error;
270
271 /* Available only for super-user */
272 if (kauth_authorize_system(l->l_cred, KAUTH_SYSTEM_PSET,
273 KAUTH_REQ_SYSTEM_PSET_CREATE, NULL, NULL, NULL))
274 return EPERM;
275
276 error = kern_pset_create(&psid);
277 if (error)
278 return error;
279
280 error = copyout(&psid, SCARG(uap, psid), sizeof(psetid_t));
281 if (error)
282 (void)kern_pset_destroy(psid);
283
284 return error;
285 }
286
287 int
288 sys_pset_destroy(struct lwp *l, const struct sys_pset_destroy_args *uap,
289 register_t *retval)
290 {
291 /* {
292 syscallarg(psetid_t) psid;
293 } */
294
295 /* Available only for super-user */
296 if (kauth_authorize_system(l->l_cred, KAUTH_SYSTEM_PSET,
297 KAUTH_REQ_SYSTEM_PSET_DESTROY,
298 KAUTH_ARG(SCARG(uap, psid)), NULL, NULL))
299 return EPERM;
300
301 return kern_pset_destroy(SCARG(uap, psid));
302 }
303
304 int
305 sys_pset_assign(struct lwp *l, const struct sys_pset_assign_args *uap,
306 register_t *retval)
307 {
308 /* {
309 syscallarg(psetid_t) psid;
310 syscallarg(cpuid_t) cpuid;
311 syscallarg(psetid_t) *opsid;
312 } */
313 struct cpu_info *ici, *ci = NULL;
314 struct schedstate_percpu *spc = NULL;
315 struct lwp *t;
316 psetid_t psid = SCARG(uap, psid), opsid = 0;
317 CPU_INFO_ITERATOR cii;
318 int error = 0, nnone = 0;
319
320 /* Available only for super-user, except the case of PS_QUERY */
321 if (kauth_authorize_system(l->l_cred, KAUTH_SYSTEM_PSET,
322 KAUTH_REQ_SYSTEM_PSET_ASSIGN, KAUTH_ARG(SCARG(uap, psid)), NULL,
323 NULL))
324 return EPERM;
325
326 /* Find the target CPU */
327 mutex_enter(&cpu_lock);
328 for (CPU_INFO_FOREACH(cii, ici)) {
329 struct schedstate_percpu *ispc;
330 ispc = &ici->ci_schedstate;
331 if (cpu_index(ici) == SCARG(uap, cpuid)) {
332 ci = ici;
333 spc = ispc;
334 }
335 nnone += (ispc->spc_psid == PS_NONE);
336 }
337 if (ci == NULL) {
338 mutex_exit(&cpu_lock);
339 return EINVAL;
340 }
341 error = psid_validate(psid, true);
342 if (error) {
343 mutex_exit(&cpu_lock);
344 return error;
345 }
346 opsid = spc->spc_psid;
347 switch (psid) {
348 case PS_QUERY:
349 break;
350 case PS_MYID:
351 psid = curlwp->l_psid;
352 /* FALLTHROUGH */
353 default:
354 /*
355 * Ensure at least one CPU stays in the default set,
356 * and that specified CPU is not offline.
357 */
358 if (psid != PS_NONE && ((spc->spc_flags & SPCF_OFFLINE) ||
359 (nnone == 1 && spc->spc_psid == PS_NONE))) {
360 mutex_exit(&cpu_lock);
361 return EBUSY;
362 }
363 mutex_enter(proc_lock);
364 /*
365 * Ensure that none of the threads are using affinity mask
366 * with this target CPU in it.
367 */
368 LIST_FOREACH(t, &alllwp, l_list) {
369 if (t->l_affinity == NULL) {
370 continue;
371 }
372 lwp_lock(t);
373 if (t->l_affinity == NULL) {
374 lwp_unlock(t);
375 continue;
376 }
377 if (kcpuset_isset(t->l_affinity, cpu_index(ci))) {
378 lwp_unlock(t);
379 mutex_exit(proc_lock);
380 mutex_exit(&cpu_lock);
381 return EPERM;
382 }
383 }
384 /*
385 * Set the processor-set ID.
386 * Migrate out any threads running on this CPU.
387 */
388 spc->spc_psid = psid;
389
390 LIST_FOREACH(t, &alllwp, l_list) {
391 struct cpu_info *tci;
392 if (t->l_cpu != ci)
393 continue;
394 if (t->l_pflag & (LP_BOUND | LP_INTR))
395 continue;
396 lwp_lock(t);
397 tci = sched_takecpu(t);
398 KASSERT(tci != ci);
399 lwp_migrate(t, tci);
400 }
401 mutex_exit(proc_lock);
402 break;
403 }
404 mutex_exit(&cpu_lock);
405
406 if (SCARG(uap, opsid) != NULL)
407 error = copyout(&opsid, SCARG(uap, opsid), sizeof(psetid_t));
408
409 return error;
410 }
411
412 int
413 sys__pset_bind(struct lwp *l, const struct sys__pset_bind_args *uap,
414 register_t *retval)
415 {
416 /* {
417 syscallarg(idtype_t) idtype;
418 syscallarg(id_t) first_id;
419 syscallarg(id_t) second_id;
420 syscallarg(psetid_t) psid;
421 syscallarg(psetid_t) *opsid;
422 } */
423 struct cpu_info *ci;
424 struct proc *p;
425 struct lwp *t;
426 id_t id1, id2;
427 pid_t pid = 0;
428 lwpid_t lid = 0;
429 psetid_t psid, opsid;
430 int error = 0, lcnt;
431
432 psid = SCARG(uap, psid);
433
434 /* Available only for super-user, except the case of PS_QUERY */
435 if (kauth_authorize_system(l->l_cred, KAUTH_SYSTEM_PSET,
436 KAUTH_REQ_SYSTEM_PSET_BIND, KAUTH_ARG(SCARG(uap, psid)), NULL,
437 NULL))
438 return EPERM;
439
440 mutex_enter(&cpu_lock);
441 error = psid_validate(psid, true);
442 if (error) {
443 mutex_exit(&cpu_lock);
444 return error;
445 }
446 if (psid == PS_MYID)
447 psid = curlwp->l_psid;
448 if (psid != PS_QUERY && psid != PS_NONE)
449 psets[psid - 1]->ps_flags |= PSET_BUSY;
450 mutex_exit(&cpu_lock);
451
452 /*
453 * Get PID and LID from the ID.
454 */
455 p = l->l_proc;
456 id1 = SCARG(uap, first_id);
457 id2 = SCARG(uap, second_id);
458
459 switch (SCARG(uap, idtype)) {
460 case P_PID:
461 /*
462 * Process:
463 * First ID - PID;
464 * Second ID - ignored;
465 */
466 pid = (id1 == P_MYID) ? p->p_pid : id1;
467 lid = 0;
468 break;
469 case P_LWPID:
470 /*
471 * Thread (LWP):
472 * First ID - LID;
473 * Second ID - PID;
474 */
475 if (id1 == P_MYID) {
476 pid = p->p_pid;
477 lid = l->l_lid;
478 break;
479 }
480 lid = id1;
481 pid = (id2 == P_MYID) ? p->p_pid : id2;
482 break;
483 default:
484 error = EINVAL;
485 goto error;
486 }
487
488 /* Find the process */
489 mutex_enter(proc_lock);
490 p = proc_find(pid);
491 if (p == NULL) {
492 mutex_exit(proc_lock);
493 error = ESRCH;
494 goto error;
495 }
496 mutex_enter(p->p_lock);
497 mutex_exit(proc_lock);
498
499 /* Disallow modification of the system processes */
500 if (p->p_flag & PK_SYSTEM) {
501 mutex_exit(p->p_lock);
502 error = EPERM;
503 goto error;
504 }
505
506 /* Find the LWP(s) */
507 lcnt = 0;
508 ci = NULL;
509 LIST_FOREACH(t, &p->p_lwps, l_sibling) {
510 if (lid && lid != t->l_lid)
511 continue;
512 /*
513 * Bind the thread to the processor-set,
514 * take some CPU and migrate.
515 */
516 lwp_lock(t);
517 opsid = t->l_psid;
518 t->l_psid = psid;
519 ci = sched_takecpu(t);
520 /* Unlocks LWP */
521 lwp_migrate(t, ci);
522 lcnt++;
523 }
524 mutex_exit(p->p_lock);
525 if (lcnt == 0) {
526 error = ESRCH;
527 goto error;
528 }
529 if (SCARG(uap, opsid))
530 error = copyout(&opsid, SCARG(uap, opsid), sizeof(psetid_t));
531 error:
532 if (psid != PS_QUERY && psid != PS_NONE) {
533 mutex_enter(&cpu_lock);
534 psets[psid - 1]->ps_flags &= ~PSET_BUSY;
535 mutex_exit(&cpu_lock);
536 }
537 return error;
538 }
539
540 /*
541 * Sysctl nodes and initialization.
542 */
543
544 static int
545 sysctl_psets_max(SYSCTLFN_ARGS)
546 {
547 struct sysctlnode node;
548 int error, newsize;
549
550 node = *rnode;
551 node.sysctl_data = &newsize;
552
553 newsize = psets_max;
554 error = sysctl_lookup(SYSCTLFN_CALL(&node));
555 if (error || newp == NULL)
556 return error;
557
558 if (newsize <= 0)
559 return EINVAL;
560
561 sysctl_unlock();
562 error = psets_realloc(newsize);
563 sysctl_relock();
564 return error;
565 }
566
567 static int
568 sysctl_psets_list(SYSCTLFN_ARGS)
569 {
570 const size_t bufsz = 1024;
571 char *buf, tbuf[16];
572 int i, error;
573 size_t len;
574
575 sysctl_unlock();
576 buf = kmem_alloc(bufsz, KM_SLEEP);
577 snprintf(buf, bufsz, "%d:1", PS_NONE); /* XXX */
578
579 mutex_enter(&cpu_lock);
580 for (i = 0; i < psets_max; i++) {
581 if (psets[i] == NULL)
582 continue;
583 snprintf(tbuf, sizeof(tbuf), ",%d:2", i + 1); /* XXX */
584 strlcat(buf, tbuf, bufsz);
585 }
586 mutex_exit(&cpu_lock);
587 len = strlen(buf) + 1;
588 error = 0;
589 if (oldp != NULL)
590 error = copyout(buf, oldp, min(len, *oldlenp));
591 *oldlenp = len;
592 kmem_free(buf, bufsz);
593 sysctl_relock();
594 return error;
595 }
596
597 SYSCTL_SETUP(sysctl_pset_setup, "sysctl kern.pset subtree setup")
598 {
599 const struct sysctlnode *node = NULL;
600
601 sysctl_createv(clog, 0, NULL, &node,
602 CTLFLAG_PERMANENT,
603 CTLTYPE_NODE, "pset",
604 SYSCTL_DESCR("Processor-set options"),
605 NULL, 0, NULL, 0,
606 CTL_KERN, CTL_CREATE, CTL_EOL);
607
608 if (node == NULL)
609 return;
610
611 sysctl_createv(clog, 0, &node, NULL,
612 CTLFLAG_PERMANENT | CTLFLAG_READWRITE,
613 CTLTYPE_INT, "psets_max",
614 SYSCTL_DESCR("Maximal count of the processor-sets"),
615 sysctl_psets_max, 0, &psets_max, 0,
616 CTL_CREATE, CTL_EOL);
617 sysctl_createv(clog, 0, &node, NULL,
618 CTLFLAG_PERMANENT,
619 CTLTYPE_STRING, "list",
620 SYSCTL_DESCR("List of active sets"),
621 sysctl_psets_list, 0, NULL, 0,
622 CTL_CREATE, CTL_EOL);
623 }
624