1 | /* $NetBSD: kern_timeout.c,v 1.51 2015/11/24 15:48:23 christos Exp $ */ |
2 | |
3 | /*- |
4 | * Copyright (c) 2003, 2006, 2007, 2008, 2009 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, and by Andrew Doran. |
9 | * |
10 | * Redistribution and use in source and binary forms, with or without |
11 | * modification, are permitted provided that the following conditions |
12 | * are met: |
13 | * 1. Redistributions of source code must retain the above copyright |
14 | * notice, this list of conditions and the following disclaimer. |
15 | * 2. Redistributions in binary form must reproduce the above copyright |
16 | * notice, this list of conditions and the following disclaimer in the |
17 | * documentation and/or other materials provided with the distribution. |
18 | * |
19 | * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS |
20 | * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED |
21 | * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
22 | * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS |
23 | * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
24 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
25 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
26 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
27 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
28 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
29 | * POSSIBILITY OF SUCH DAMAGE. |
30 | */ |
31 | |
32 | /* |
33 | * Copyright (c) 2001 Thomas Nordin <nordin@openbsd.org> |
34 | * Copyright (c) 2000-2001 Artur Grabowski <art@openbsd.org> |
35 | * All rights reserved. |
36 | * |
37 | * Redistribution and use in source and binary forms, with or without |
38 | * modification, are permitted provided that the following conditions |
39 | * are met: |
40 | * |
41 | * 1. Redistributions of source code must retain the above copyright |
42 | * notice, this list of conditions and the following disclaimer. |
43 | * 2. Redistributions in binary form must reproduce the above copyright |
44 | * notice, this list of conditions and the following disclaimer in the |
45 | * documentation and/or other materials provided with the distribution. |
46 | * 3. The name of the author may not be used to endorse or promote products |
47 | * derived from this software without specific prior written permission. |
48 | * |
49 | * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, |
50 | * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY |
51 | * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL |
52 | * THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
53 | * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
54 | * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; |
55 | * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, |
56 | * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR |
57 | * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF |
58 | * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
59 | */ |
60 | |
61 | #include <sys/cdefs.h> |
62 | __KERNEL_RCSID(0, "$NetBSD: kern_timeout.c,v 1.51 2015/11/24 15:48:23 christos Exp $" ); |
63 | |
64 | /* |
65 | * Timeouts are kept in a hierarchical timing wheel. The c_time is the |
66 | * value of c_cpu->cc_ticks when the timeout should be called. There are |
67 | * four levels with 256 buckets each. See 'Scheme 7' in "Hashed and |
68 | * Hierarchical Timing Wheels: Efficient Data Structures for Implementing |
69 | * a Timer Facility" by George Varghese and Tony Lauck. |
70 | * |
71 | * Some of the "math" in here is a bit tricky. We have to beware of |
72 | * wrapping ints. |
73 | * |
74 | * We use the fact that any element added to the queue must be added with |
75 | * a positive time. That means that any element `to' on the queue cannot |
76 | * be scheduled to timeout further in time than INT_MAX, but c->c_time can |
77 | * be positive or negative so comparing it with anything is dangerous. |
78 | * The only way we can use the c->c_time value in any predictable way is |
79 | * when we calculate how far in the future `to' will timeout - "c->c_time |
80 | * - c->c_cpu->cc_ticks". The result will always be positive for future |
81 | * timeouts and 0 or negative for due timeouts. |
82 | */ |
83 | |
84 | #define _CALLOUT_PRIVATE |
85 | |
86 | #include <sys/param.h> |
87 | #include <sys/systm.h> |
88 | #include <sys/kernel.h> |
89 | #include <sys/callout.h> |
90 | #include <sys/lwp.h> |
91 | #include <sys/mutex.h> |
92 | #include <sys/proc.h> |
93 | #include <sys/sleepq.h> |
94 | #include <sys/syncobj.h> |
95 | #include <sys/evcnt.h> |
96 | #include <sys/intr.h> |
97 | #include <sys/cpu.h> |
98 | #include <sys/kmem.h> |
99 | |
100 | #ifdef DDB |
101 | #include <machine/db_machdep.h> |
102 | #include <ddb/db_interface.h> |
103 | #include <ddb/db_access.h> |
104 | #include <ddb/db_cpu.h> |
105 | #include <ddb/db_sym.h> |
106 | #include <ddb/db_output.h> |
107 | #endif |
108 | |
109 | #define BUCKETS 1024 |
110 | #define WHEELSIZE 256 |
111 | #define WHEELMASK 255 |
112 | #define WHEELBITS 8 |
113 | |
114 | #define MASKWHEEL(wheel, time) (((time) >> ((wheel)*WHEELBITS)) & WHEELMASK) |
115 | |
116 | #define BUCKET(cc, rel, abs) \ |
117 | (((rel) <= (1 << (2*WHEELBITS))) \ |
118 | ? ((rel) <= (1 << WHEELBITS)) \ |
119 | ? &(cc)->cc_wheel[MASKWHEEL(0, (abs))] \ |
120 | : &(cc)->cc_wheel[MASKWHEEL(1, (abs)) + WHEELSIZE] \ |
121 | : ((rel) <= (1 << (3*WHEELBITS))) \ |
122 | ? &(cc)->cc_wheel[MASKWHEEL(2, (abs)) + 2*WHEELSIZE] \ |
123 | : &(cc)->cc_wheel[MASKWHEEL(3, (abs)) + 3*WHEELSIZE]) |
124 | |
125 | #define MOVEBUCKET(cc, wheel, time) \ |
126 | CIRCQ_APPEND(&(cc)->cc_todo, \ |
127 | &(cc)->cc_wheel[MASKWHEEL((wheel), (time)) + (wheel)*WHEELSIZE]) |
128 | |
129 | /* |
130 | * Circular queue definitions. |
131 | */ |
132 | |
133 | #define CIRCQ_INIT(list) \ |
134 | do { \ |
135 | (list)->cq_next_l = (list); \ |
136 | (list)->cq_prev_l = (list); \ |
137 | } while (/*CONSTCOND*/0) |
138 | |
139 | #define CIRCQ_INSERT(elem, list) \ |
140 | do { \ |
141 | (elem)->cq_prev_e = (list)->cq_prev_e; \ |
142 | (elem)->cq_next_l = (list); \ |
143 | (list)->cq_prev_l->cq_next_l = (elem); \ |
144 | (list)->cq_prev_l = (elem); \ |
145 | } while (/*CONSTCOND*/0) |
146 | |
147 | #define CIRCQ_APPEND(fst, snd) \ |
148 | do { \ |
149 | if (!CIRCQ_EMPTY(snd)) { \ |
150 | (fst)->cq_prev_l->cq_next_l = (snd)->cq_next_l; \ |
151 | (snd)->cq_next_l->cq_prev_l = (fst)->cq_prev_l; \ |
152 | (snd)->cq_prev_l->cq_next_l = (fst); \ |
153 | (fst)->cq_prev_l = (snd)->cq_prev_l; \ |
154 | CIRCQ_INIT(snd); \ |
155 | } \ |
156 | } while (/*CONSTCOND*/0) |
157 | |
158 | #define CIRCQ_REMOVE(elem) \ |
159 | do { \ |
160 | (elem)->cq_next_l->cq_prev_e = (elem)->cq_prev_e; \ |
161 | (elem)->cq_prev_l->cq_next_e = (elem)->cq_next_e; \ |
162 | } while (/*CONSTCOND*/0) |
163 | |
164 | #define CIRCQ_FIRST(list) ((list)->cq_next_e) |
165 | #define CIRCQ_NEXT(elem) ((elem)->cq_next_e) |
166 | #define CIRCQ_LAST(elem,list) ((elem)->cq_next_l == (list)) |
167 | #define CIRCQ_EMPTY(list) ((list)->cq_next_l == (list)) |
168 | |
169 | struct callout_cpu { |
170 | kmutex_t *cc_lock; |
171 | sleepq_t cc_sleepq; |
172 | u_int cc_nwait; |
173 | u_int cc_ticks; |
174 | lwp_t *cc_lwp; |
175 | callout_impl_t *cc_active; |
176 | callout_impl_t *cc_cancel; |
177 | struct evcnt cc_ev_late; |
178 | struct evcnt cc_ev_block; |
179 | struct callout_circq cc_todo; /* Worklist */ |
180 | struct callout_circq cc_wheel[BUCKETS]; /* Queues of timeouts */ |
181 | char cc_name1[12]; |
182 | char cc_name2[12]; |
183 | }; |
184 | |
185 | #ifndef CRASH |
186 | |
187 | static void callout_softclock(void *); |
188 | static struct callout_cpu callout_cpu0; |
189 | static void *callout_sih; |
190 | |
191 | static inline kmutex_t * |
192 | callout_lock(callout_impl_t *c) |
193 | { |
194 | struct callout_cpu *cc; |
195 | kmutex_t *lock; |
196 | |
197 | for (;;) { |
198 | cc = c->c_cpu; |
199 | lock = cc->cc_lock; |
200 | mutex_spin_enter(lock); |
201 | if (__predict_true(cc == c->c_cpu)) |
202 | return lock; |
203 | mutex_spin_exit(lock); |
204 | } |
205 | } |
206 | |
207 | /* |
208 | * callout_startup: |
209 | * |
210 | * Initialize the callout facility, called at system startup time. |
211 | * Do just enough to allow callouts to be safely registered. |
212 | */ |
213 | void |
214 | callout_startup(void) |
215 | { |
216 | struct callout_cpu *cc; |
217 | int b; |
218 | |
219 | KASSERT(curcpu()->ci_data.cpu_callout == NULL); |
220 | |
221 | cc = &callout_cpu0; |
222 | cc->cc_lock = mutex_obj_alloc(MUTEX_DEFAULT, IPL_SCHED); |
223 | CIRCQ_INIT(&cc->cc_todo); |
224 | for (b = 0; b < BUCKETS; b++) |
225 | CIRCQ_INIT(&cc->cc_wheel[b]); |
226 | curcpu()->ci_data.cpu_callout = cc; |
227 | } |
228 | |
229 | /* |
230 | * callout_init_cpu: |
231 | * |
232 | * Per-CPU initialization. |
233 | */ |
234 | CTASSERT(sizeof(callout_impl_t) <= sizeof(callout_t)); |
235 | |
236 | void |
237 | callout_init_cpu(struct cpu_info *ci) |
238 | { |
239 | struct callout_cpu *cc; |
240 | int b; |
241 | |
242 | if ((cc = ci->ci_data.cpu_callout) == NULL) { |
243 | cc = kmem_zalloc(sizeof(*cc), KM_SLEEP); |
244 | if (cc == NULL) |
245 | panic("callout_init_cpu (1)" ); |
246 | cc->cc_lock = mutex_obj_alloc(MUTEX_DEFAULT, IPL_SCHED); |
247 | CIRCQ_INIT(&cc->cc_todo); |
248 | for (b = 0; b < BUCKETS; b++) |
249 | CIRCQ_INIT(&cc->cc_wheel[b]); |
250 | } else { |
251 | /* Boot CPU, one time only. */ |
252 | callout_sih = softint_establish(SOFTINT_CLOCK | SOFTINT_MPSAFE, |
253 | callout_softclock, NULL); |
254 | if (callout_sih == NULL) |
255 | panic("callout_init_cpu (2)" ); |
256 | } |
257 | |
258 | sleepq_init(&cc->cc_sleepq); |
259 | |
260 | snprintf(cc->cc_name1, sizeof(cc->cc_name1), "late/%u" , |
261 | cpu_index(ci)); |
262 | evcnt_attach_dynamic(&cc->cc_ev_late, EVCNT_TYPE_MISC, |
263 | NULL, "callout" , cc->cc_name1); |
264 | |
265 | snprintf(cc->cc_name2, sizeof(cc->cc_name2), "wait/%u" , |
266 | cpu_index(ci)); |
267 | evcnt_attach_dynamic(&cc->cc_ev_block, EVCNT_TYPE_MISC, |
268 | NULL, "callout" , cc->cc_name2); |
269 | |
270 | ci->ci_data.cpu_callout = cc; |
271 | } |
272 | |
273 | /* |
274 | * callout_init: |
275 | * |
276 | * Initialize a callout structure. This must be quick, so we fill |
277 | * only the minimum number of fields. |
278 | */ |
279 | void |
280 | callout_init(callout_t *cs, u_int flags) |
281 | { |
282 | callout_impl_t *c = (callout_impl_t *)cs; |
283 | struct callout_cpu *cc; |
284 | |
285 | KASSERT((flags & ~CALLOUT_FLAGMASK) == 0); |
286 | |
287 | cc = curcpu()->ci_data.cpu_callout; |
288 | c->c_func = NULL; |
289 | c->c_magic = CALLOUT_MAGIC; |
290 | if (__predict_true((flags & CALLOUT_MPSAFE) != 0 && cc != NULL)) { |
291 | c->c_flags = flags; |
292 | c->c_cpu = cc; |
293 | return; |
294 | } |
295 | c->c_flags = flags | CALLOUT_BOUND; |
296 | c->c_cpu = &callout_cpu0; |
297 | } |
298 | |
299 | /* |
300 | * callout_destroy: |
301 | * |
302 | * Destroy a callout structure. The callout must be stopped. |
303 | */ |
304 | void |
305 | callout_destroy(callout_t *cs) |
306 | { |
307 | callout_impl_t *c = (callout_impl_t *)cs; |
308 | |
309 | /* |
310 | * It's not necessary to lock in order to see the correct value |
311 | * of c->c_flags. If the callout could potentially have been |
312 | * running, the current thread should have stopped it. |
313 | */ |
314 | KASSERTMSG((c->c_flags & CALLOUT_PENDING) == 0, |
315 | "callout %p: c_func (%p) c_flags (%#x) destroyed from %p" , |
316 | c, c->c_func, c->c_flags, __builtin_return_address(0)); |
317 | KASSERT(c->c_cpu->cc_lwp == curlwp || c->c_cpu->cc_active != c); |
318 | KASSERTMSG(c->c_magic == CALLOUT_MAGIC, |
319 | "callout %p: c_magic (%#x) != CALLOUT_MAGIC (%#x)" , |
320 | c, c->c_magic, CALLOUT_MAGIC); |
321 | c->c_magic = 0; |
322 | } |
323 | |
324 | /* |
325 | * callout_schedule_locked: |
326 | * |
327 | * Schedule a callout to run. The function and argument must |
328 | * already be set in the callout structure. Must be called with |
329 | * callout_lock. |
330 | */ |
331 | static void |
332 | callout_schedule_locked(callout_impl_t *c, kmutex_t *lock, int to_ticks) |
333 | { |
334 | struct callout_cpu *cc, *occ; |
335 | int old_time; |
336 | |
337 | KASSERT(to_ticks >= 0); |
338 | KASSERT(c->c_func != NULL); |
339 | |
340 | /* Initialize the time here, it won't change. */ |
341 | occ = c->c_cpu; |
342 | c->c_flags &= ~(CALLOUT_FIRED | CALLOUT_INVOKING); |
343 | |
344 | /* |
345 | * If this timeout is already scheduled and now is moved |
346 | * earlier, reschedule it now. Otherwise leave it in place |
347 | * and let it be rescheduled later. |
348 | */ |
349 | if ((c->c_flags & CALLOUT_PENDING) != 0) { |
350 | /* Leave on existing CPU. */ |
351 | old_time = c->c_time; |
352 | c->c_time = to_ticks + occ->cc_ticks; |
353 | if (c->c_time - old_time < 0) { |
354 | CIRCQ_REMOVE(&c->c_list); |
355 | CIRCQ_INSERT(&c->c_list, &occ->cc_todo); |
356 | } |
357 | mutex_spin_exit(lock); |
358 | return; |
359 | } |
360 | |
361 | cc = curcpu()->ci_data.cpu_callout; |
362 | if ((c->c_flags & CALLOUT_BOUND) != 0 || cc == occ || |
363 | !mutex_tryenter(cc->cc_lock)) { |
364 | /* Leave on existing CPU. */ |
365 | c->c_time = to_ticks + occ->cc_ticks; |
366 | c->c_flags |= CALLOUT_PENDING; |
367 | CIRCQ_INSERT(&c->c_list, &occ->cc_todo); |
368 | } else { |
369 | /* Move to this CPU. */ |
370 | c->c_cpu = cc; |
371 | c->c_time = to_ticks + cc->cc_ticks; |
372 | c->c_flags |= CALLOUT_PENDING; |
373 | CIRCQ_INSERT(&c->c_list, &cc->cc_todo); |
374 | mutex_spin_exit(cc->cc_lock); |
375 | } |
376 | mutex_spin_exit(lock); |
377 | } |
378 | |
379 | /* |
380 | * callout_reset: |
381 | * |
382 | * Reset a callout structure with a new function and argument, and |
383 | * schedule it to run. |
384 | */ |
385 | void |
386 | callout_reset(callout_t *cs, int to_ticks, void (*func)(void *), void *arg) |
387 | { |
388 | callout_impl_t *c = (callout_impl_t *)cs; |
389 | kmutex_t *lock; |
390 | |
391 | KASSERT(c->c_magic == CALLOUT_MAGIC); |
392 | KASSERT(func != NULL); |
393 | |
394 | lock = callout_lock(c); |
395 | c->c_func = func; |
396 | c->c_arg = arg; |
397 | callout_schedule_locked(c, lock, to_ticks); |
398 | } |
399 | |
400 | /* |
401 | * callout_schedule: |
402 | * |
403 | * Schedule a callout to run. The function and argument must |
404 | * already be set in the callout structure. |
405 | */ |
406 | void |
407 | callout_schedule(callout_t *cs, int to_ticks) |
408 | { |
409 | callout_impl_t *c = (callout_impl_t *)cs; |
410 | kmutex_t *lock; |
411 | |
412 | KASSERT(c->c_magic == CALLOUT_MAGIC); |
413 | |
414 | lock = callout_lock(c); |
415 | callout_schedule_locked(c, lock, to_ticks); |
416 | } |
417 | |
418 | /* |
419 | * callout_stop: |
420 | * |
421 | * Try to cancel a pending callout. It may be too late: the callout |
422 | * could be running on another CPU. If called from interrupt context, |
423 | * the callout could already be in progress at a lower priority. |
424 | */ |
425 | bool |
426 | callout_stop(callout_t *cs) |
427 | { |
428 | callout_impl_t *c = (callout_impl_t *)cs; |
429 | struct callout_cpu *cc; |
430 | kmutex_t *lock; |
431 | bool expired; |
432 | |
433 | KASSERT(c->c_magic == CALLOUT_MAGIC); |
434 | |
435 | lock = callout_lock(c); |
436 | |
437 | if ((c->c_flags & CALLOUT_PENDING) != 0) |
438 | CIRCQ_REMOVE(&c->c_list); |
439 | expired = ((c->c_flags & CALLOUT_FIRED) != 0); |
440 | c->c_flags &= ~(CALLOUT_PENDING|CALLOUT_FIRED); |
441 | |
442 | cc = c->c_cpu; |
443 | if (cc->cc_active == c) { |
444 | /* |
445 | * This is for non-MPSAFE callouts only. To synchronize |
446 | * effectively we must be called with kernel_lock held. |
447 | * It's also taken in callout_softclock. |
448 | */ |
449 | cc->cc_cancel = c; |
450 | } |
451 | |
452 | mutex_spin_exit(lock); |
453 | |
454 | return expired; |
455 | } |
456 | |
457 | /* |
458 | * callout_halt: |
459 | * |
460 | * Cancel a pending callout. If in-flight, block until it completes. |
461 | * May not be called from a hard interrupt handler. If the callout |
462 | * can take locks, the caller of callout_halt() must not hold any of |
463 | * those locks, otherwise the two could deadlock. If 'interlock' is |
464 | * non-NULL and we must wait for the callout to complete, it will be |
465 | * released and re-acquired before returning. |
466 | */ |
467 | bool |
468 | callout_halt(callout_t *cs, void *interlock) |
469 | { |
470 | callout_impl_t *c = (callout_impl_t *)cs; |
471 | struct callout_cpu *cc; |
472 | struct lwp *l; |
473 | kmutex_t *lock, *relock; |
474 | bool expired; |
475 | |
476 | KASSERT(c->c_magic == CALLOUT_MAGIC); |
477 | KASSERT(!cpu_intr_p()); |
478 | |
479 | lock = callout_lock(c); |
480 | relock = NULL; |
481 | |
482 | expired = ((c->c_flags & CALLOUT_FIRED) != 0); |
483 | if ((c->c_flags & CALLOUT_PENDING) != 0) |
484 | CIRCQ_REMOVE(&c->c_list); |
485 | c->c_flags &= ~(CALLOUT_PENDING|CALLOUT_FIRED); |
486 | |
487 | l = curlwp; |
488 | for (;;) { |
489 | cc = c->c_cpu; |
490 | if (__predict_true(cc->cc_active != c || cc->cc_lwp == l)) |
491 | break; |
492 | if (interlock != NULL) { |
493 | /* |
494 | * Avoid potential scheduler lock order problems by |
495 | * dropping the interlock without the callout lock |
496 | * held. |
497 | */ |
498 | mutex_spin_exit(lock); |
499 | mutex_exit(interlock); |
500 | relock = interlock; |
501 | interlock = NULL; |
502 | } else { |
503 | /* XXX Better to do priority inheritance. */ |
504 | KASSERT(l->l_wchan == NULL); |
505 | cc->cc_nwait++; |
506 | cc->cc_ev_block.ev_count++; |
507 | l->l_kpriority = true; |
508 | sleepq_enter(&cc->cc_sleepq, l, cc->cc_lock); |
509 | sleepq_enqueue(&cc->cc_sleepq, cc, "callout" , |
510 | &sleep_syncobj); |
511 | sleepq_block(0, false); |
512 | } |
513 | lock = callout_lock(c); |
514 | } |
515 | |
516 | mutex_spin_exit(lock); |
517 | if (__predict_false(relock != NULL)) |
518 | mutex_enter(relock); |
519 | |
520 | return expired; |
521 | } |
522 | |
523 | #ifdef notyet |
524 | /* |
525 | * callout_bind: |
526 | * |
527 | * Bind a callout so that it will only execute on one CPU. |
528 | * The callout must be stopped, and must be MPSAFE. |
529 | * |
530 | * XXX Disabled for now until it is decided how to handle |
531 | * offlined CPUs. We may want weak+strong binding. |
532 | */ |
533 | void |
534 | callout_bind(callout_t *cs, struct cpu_info *ci) |
535 | { |
536 | callout_impl_t *c = (callout_impl_t *)cs; |
537 | struct callout_cpu *cc; |
538 | kmutex_t *lock; |
539 | |
540 | KASSERT((c->c_flags & CALLOUT_PENDING) == 0); |
541 | KASSERT(c->c_cpu->cc_active != c); |
542 | KASSERT(c->c_magic == CALLOUT_MAGIC); |
543 | KASSERT((c->c_flags & CALLOUT_MPSAFE) != 0); |
544 | |
545 | lock = callout_lock(c); |
546 | cc = ci->ci_data.cpu_callout; |
547 | c->c_flags |= CALLOUT_BOUND; |
548 | if (c->c_cpu != cc) { |
549 | /* |
550 | * Assigning c_cpu effectively unlocks the callout |
551 | * structure, as we don't hold the new CPU's lock. |
552 | * Issue memory barrier to prevent accesses being |
553 | * reordered. |
554 | */ |
555 | membar_exit(); |
556 | c->c_cpu = cc; |
557 | } |
558 | mutex_spin_exit(lock); |
559 | } |
560 | #endif |
561 | |
562 | void |
563 | callout_setfunc(callout_t *cs, void (*func)(void *), void *arg) |
564 | { |
565 | callout_impl_t *c = (callout_impl_t *)cs; |
566 | kmutex_t *lock; |
567 | |
568 | KASSERT(c->c_magic == CALLOUT_MAGIC); |
569 | KASSERT(func != NULL); |
570 | |
571 | lock = callout_lock(c); |
572 | c->c_func = func; |
573 | c->c_arg = arg; |
574 | mutex_spin_exit(lock); |
575 | } |
576 | |
577 | bool |
578 | callout_expired(callout_t *cs) |
579 | { |
580 | callout_impl_t *c = (callout_impl_t *)cs; |
581 | kmutex_t *lock; |
582 | bool rv; |
583 | |
584 | KASSERT(c->c_magic == CALLOUT_MAGIC); |
585 | |
586 | lock = callout_lock(c); |
587 | rv = ((c->c_flags & CALLOUT_FIRED) != 0); |
588 | mutex_spin_exit(lock); |
589 | |
590 | return rv; |
591 | } |
592 | |
593 | bool |
594 | callout_active(callout_t *cs) |
595 | { |
596 | callout_impl_t *c = (callout_impl_t *)cs; |
597 | kmutex_t *lock; |
598 | bool rv; |
599 | |
600 | KASSERT(c->c_magic == CALLOUT_MAGIC); |
601 | |
602 | lock = callout_lock(c); |
603 | rv = ((c->c_flags & (CALLOUT_PENDING|CALLOUT_FIRED)) != 0); |
604 | mutex_spin_exit(lock); |
605 | |
606 | return rv; |
607 | } |
608 | |
609 | bool |
610 | callout_pending(callout_t *cs) |
611 | { |
612 | callout_impl_t *c = (callout_impl_t *)cs; |
613 | kmutex_t *lock; |
614 | bool rv; |
615 | |
616 | KASSERT(c->c_magic == CALLOUT_MAGIC); |
617 | |
618 | lock = callout_lock(c); |
619 | rv = ((c->c_flags & CALLOUT_PENDING) != 0); |
620 | mutex_spin_exit(lock); |
621 | |
622 | return rv; |
623 | } |
624 | |
625 | bool |
626 | callout_invoking(callout_t *cs) |
627 | { |
628 | callout_impl_t *c = (callout_impl_t *)cs; |
629 | kmutex_t *lock; |
630 | bool rv; |
631 | |
632 | KASSERT(c->c_magic == CALLOUT_MAGIC); |
633 | |
634 | lock = callout_lock(c); |
635 | rv = ((c->c_flags & CALLOUT_INVOKING) != 0); |
636 | mutex_spin_exit(lock); |
637 | |
638 | return rv; |
639 | } |
640 | |
641 | void |
642 | callout_ack(callout_t *cs) |
643 | { |
644 | callout_impl_t *c = (callout_impl_t *)cs; |
645 | kmutex_t *lock; |
646 | |
647 | KASSERT(c->c_magic == CALLOUT_MAGIC); |
648 | |
649 | lock = callout_lock(c); |
650 | c->c_flags &= ~CALLOUT_INVOKING; |
651 | mutex_spin_exit(lock); |
652 | } |
653 | |
654 | /* |
655 | * callout_hardclock: |
656 | * |
657 | * Called from hardclock() once every tick. We schedule a soft |
658 | * interrupt if there is work to be done. |
659 | */ |
660 | void |
661 | callout_hardclock(void) |
662 | { |
663 | struct callout_cpu *cc; |
664 | int needsoftclock, ticks; |
665 | |
666 | cc = curcpu()->ci_data.cpu_callout; |
667 | mutex_spin_enter(cc->cc_lock); |
668 | |
669 | ticks = ++cc->cc_ticks; |
670 | |
671 | MOVEBUCKET(cc, 0, ticks); |
672 | if (MASKWHEEL(0, ticks) == 0) { |
673 | MOVEBUCKET(cc, 1, ticks); |
674 | if (MASKWHEEL(1, ticks) == 0) { |
675 | MOVEBUCKET(cc, 2, ticks); |
676 | if (MASKWHEEL(2, ticks) == 0) |
677 | MOVEBUCKET(cc, 3, ticks); |
678 | } |
679 | } |
680 | |
681 | needsoftclock = !CIRCQ_EMPTY(&cc->cc_todo); |
682 | mutex_spin_exit(cc->cc_lock); |
683 | |
684 | if (needsoftclock) |
685 | softint_schedule(callout_sih); |
686 | } |
687 | |
688 | /* |
689 | * callout_softclock: |
690 | * |
691 | * Soft interrupt handler, scheduled above if there is work to |
692 | * be done. Callouts are made in soft interrupt context. |
693 | */ |
694 | static void |
695 | callout_softclock(void *v) |
696 | { |
697 | callout_impl_t *c; |
698 | struct callout_cpu *cc; |
699 | void (*func)(void *); |
700 | void *arg; |
701 | int mpsafe, count, ticks, delta; |
702 | lwp_t *l; |
703 | |
704 | l = curlwp; |
705 | KASSERT(l->l_cpu == curcpu()); |
706 | cc = l->l_cpu->ci_data.cpu_callout; |
707 | |
708 | mutex_spin_enter(cc->cc_lock); |
709 | cc->cc_lwp = l; |
710 | while (!CIRCQ_EMPTY(&cc->cc_todo)) { |
711 | c = CIRCQ_FIRST(&cc->cc_todo); |
712 | KASSERT(c->c_magic == CALLOUT_MAGIC); |
713 | KASSERT(c->c_func != NULL); |
714 | KASSERT(c->c_cpu == cc); |
715 | KASSERT((c->c_flags & CALLOUT_PENDING) != 0); |
716 | KASSERT((c->c_flags & CALLOUT_FIRED) == 0); |
717 | CIRCQ_REMOVE(&c->c_list); |
718 | |
719 | /* If due run it, otherwise insert it into the right bucket. */ |
720 | ticks = cc->cc_ticks; |
721 | delta = c->c_time - ticks; |
722 | if (delta > 0) { |
723 | CIRCQ_INSERT(&c->c_list, BUCKET(cc, delta, c->c_time)); |
724 | continue; |
725 | } |
726 | if (delta < 0) |
727 | cc->cc_ev_late.ev_count++; |
728 | |
729 | c->c_flags = (c->c_flags & ~CALLOUT_PENDING) | |
730 | (CALLOUT_FIRED | CALLOUT_INVOKING); |
731 | mpsafe = (c->c_flags & CALLOUT_MPSAFE); |
732 | func = c->c_func; |
733 | arg = c->c_arg; |
734 | cc->cc_active = c; |
735 | |
736 | mutex_spin_exit(cc->cc_lock); |
737 | KASSERT(func != NULL); |
738 | if (__predict_false(!mpsafe)) { |
739 | KERNEL_LOCK(1, NULL); |
740 | (*func)(arg); |
741 | KERNEL_UNLOCK_ONE(NULL); |
742 | } else |
743 | (*func)(arg); |
744 | mutex_spin_enter(cc->cc_lock); |
745 | |
746 | /* |
747 | * We can't touch 'c' here because it might be |
748 | * freed already. If LWPs waiting for callout |
749 | * to complete, awaken them. |
750 | */ |
751 | cc->cc_active = NULL; |
752 | if ((count = cc->cc_nwait) != 0) { |
753 | cc->cc_nwait = 0; |
754 | /* sleepq_wake() drops the lock. */ |
755 | sleepq_wake(&cc->cc_sleepq, cc, count, cc->cc_lock); |
756 | mutex_spin_enter(cc->cc_lock); |
757 | } |
758 | } |
759 | cc->cc_lwp = NULL; |
760 | mutex_spin_exit(cc->cc_lock); |
761 | } |
762 | #endif |
763 | |
764 | #ifdef DDB |
765 | static void |
766 | db_show_callout_bucket(struct callout_cpu *cc, struct callout_circq *kbucket, |
767 | struct callout_circq *bucket) |
768 | { |
769 | callout_impl_t *c, ci; |
770 | db_expr_t offset; |
771 | const char *name; |
772 | static char question[] = "?" ; |
773 | int b; |
774 | |
775 | if (CIRCQ_LAST(bucket, kbucket)) |
776 | return; |
777 | |
778 | for (c = CIRCQ_FIRST(bucket); /*nothing*/; c = CIRCQ_NEXT(&c->c_list)) { |
779 | db_read_bytes((db_addr_t)c, sizeof(ci), (char *)&ci); |
780 | c = &ci; |
781 | db_find_sym_and_offset((db_addr_t)(intptr_t)c->c_func, &name, |
782 | &offset); |
783 | name = name ? name : question; |
784 | b = (bucket - cc->cc_wheel); |
785 | if (b < 0) |
786 | b = -WHEELSIZE; |
787 | db_printf("%9d %2d/%-4d %16lx %s\n" , |
788 | c->c_time - cc->cc_ticks, b / WHEELSIZE, b, |
789 | (u_long)c->c_arg, name); |
790 | if (CIRCQ_LAST(&c->c_list, kbucket)) |
791 | break; |
792 | } |
793 | } |
794 | |
795 | void |
796 | db_show_callout(db_expr_t addr, bool haddr, db_expr_t count, const char *modif) |
797 | { |
798 | struct callout_cpu *cc, ccb; |
799 | struct cpu_info *ci, cib; |
800 | int b; |
801 | |
802 | #ifndef CRASH |
803 | db_printf("hardclock_ticks now: %d\n" , hardclock_ticks); |
804 | #endif |
805 | db_printf(" ticks wheel arg func\n" ); |
806 | |
807 | /* |
808 | * Don't lock the callwheel; all the other CPUs are paused |
809 | * anyhow, and we might be called in a circumstance where |
810 | * some other CPU was paused while holding the lock. |
811 | */ |
812 | for (ci = db_cpu_first(); ci != NULL; ci = db_cpu_next(ci)) { |
813 | db_read_bytes((db_addr_t)ci, sizeof(cib), (char *)&cib); |
814 | cc = cib.ci_data.cpu_callout; |
815 | db_read_bytes((db_addr_t)cc, sizeof(ccb), (char *)&ccb); |
816 | db_show_callout_bucket(&ccb, &cc->cc_todo, &ccb.cc_todo); |
817 | } |
818 | for (b = 0; b < BUCKETS; b++) { |
819 | for (ci = db_cpu_first(); ci != NULL; ci = db_cpu_next(ci)) { |
820 | db_read_bytes((db_addr_t)ci, sizeof(cib), (char *)&cib); |
821 | cc = cib.ci_data.cpu_callout; |
822 | db_read_bytes((db_addr_t)cc, sizeof(ccb), (char *)&ccb); |
823 | db_show_callout_bucket(&ccb, &cc->cc_wheel[b], |
824 | &ccb.cc_wheel[b]); |
825 | } |
826 | } |
827 | } |
828 | #endif /* DDB */ |
829 | |