Rename printf -> kprintf in sys/ and add some defines where necessary
[dragonfly.git] / sys / kern / kern_timeout.c
CommitLineData
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1/*
2 * Copyright (c) 2004 The DragonFly Project. All rights reserved.
3 *
4 * This code is derived from software contributed to The DragonFly Project
5 * by Matthew Dillon <dillon@backplane.com>
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 *
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in
15 * the documentation and/or other materials provided with the
16 * distribution.
17 * 3. Neither the name of The DragonFly Project nor the names of its
18 * contributors may be used to endorse or promote products derived
19 * from this software without specific, prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
25 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
26 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34/*
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35 * Copyright (c) 1982, 1986, 1991, 1993
36 * The Regents of the University of California. All rights reserved.
37 * (c) UNIX System Laboratories, Inc.
38 * All or some portions of this file are derived from material licensed
39 * to the University of California by American Telephone and Telegraph
40 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
41 * the permission of UNIX System Laboratories, Inc.
42 *
43 * Redistribution and use in source and binary forms, with or without
44 * modification, are permitted provided that the following conditions
45 * are met:
46 * 1. Redistributions of source code must retain the above copyright
47 * notice, this list of conditions and the following disclaimer.
48 * 2. Redistributions in binary form must reproduce the above copyright
49 * notice, this list of conditions and the following disclaimer in the
50 * documentation and/or other materials provided with the distribution.
51 * 3. All advertising materials mentioning features or use of this software
52 * must display the following acknowledgement:
53 * This product includes software developed by the University of
54 * California, Berkeley and its contributors.
55 * 4. Neither the name of the University nor the names of its contributors
56 * may be used to endorse or promote products derived from this software
57 * without specific prior written permission.
58 *
59 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
60 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
61 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
62 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
63 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
64 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
65 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
66 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
67 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
68 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
69 * SUCH DAMAGE.
70 *
71 * From: @(#)kern_clock.c 8.5 (Berkeley) 1/21/94
72 * $FreeBSD: src/sys/kern/kern_timeout.c,v 1.59.2.1 2001/11/13 18:24:52 archie Exp $
6ea70f76 73 * $DragonFly: src/sys/kern/kern_timeout.c,v 1.24 2006/12/23 00:35:04 swildner Exp $
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74 */
75/*
76 * DRAGONFLY BGL STATUS
77 *
78 * All the API functions should be MP safe.
79 *
80 * The callback functions will be flagged as being MP safe if the
81 * timeout structure is initialized with callout_init_mp() instead of
82 * callout_init().
83 *
84 * The helper threads cannot be made preempt-capable until after we
85 * clean up all the uses of splsoftclock() and related interlocks (which
86 * require the related functions to be MP safe as well).
87 */
88/*
89 * The callout mechanism is based on the work of Adam M. Costello and
90 * George Varghese, published in a technical report entitled "Redesigning
91 * the BSD Callout and Timer Facilities" and modified slightly for inclusion
92 * in FreeBSD by Justin T. Gibbs. The original work on the data structures
93 * used in this implementation was published by G. Varghese and T. Lauck in
94 * the paper "Hashed and Hierarchical Timing Wheels: Data Structures for
95 * the Efficient Implementation of a Timer Facility" in the Proceedings of
96 * the 11th ACM Annual Symposium on Operating Systems Principles,
97 * Austin, Texas Nov 1987.
98 *
99 * The per-cpu augmentation was done by Matthew Dillon.
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100 */
101
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102#include "opt_ddb.h"
103
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104#include <sys/param.h>
105#include <sys/systm.h>
106#include <sys/callout.h>
107#include <sys/kernel.h>
ef0fdad1 108#include <sys/interrupt.h>
4b5f931b 109#include <sys/thread.h>
88c4d2f6 110#include <sys/thread2.h>
4ac1a4cd 111#include <ddb/ddb.h>
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112
113#ifndef MAX_SOFTCLOCK_STEPS
114#define MAX_SOFTCLOCK_STEPS 100 /* Maximum allowed value of steps. */
115#endif
116
117
118struct softclock_pcpu {
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119 struct callout_tailq *callwheel;
120 struct callout * volatile next;
121 int softticks; /* softticks index */
122 int curticks; /* per-cpu ticks counter */
123 int isrunning;
124 struct thread thread;
125
126};
127
128typedef struct softclock_pcpu *softclock_pcpu_t;
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129
130/*
131 * TODO:
132 * allocate more timeout table slots when table overflows.
133 */
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134static MALLOC_DEFINE(M_CALLOUT, "callout", "callout structures");
135static int callwheelsize;
136static int callwheelbits;
137static int callwheelmask;
138static struct softclock_pcpu softclock_pcpu_ary[MAXCPU];
139
140static void softclock_handler(void *arg);
141
142static void
143swi_softclock_setup(void *arg)
144{
145 int cpu;
146 int i;
984263bc 147
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148 /*
149 * Figure out how large a callwheel we need. It must be a power of 2.
150 */
151 callwheelsize = 1;
152 callwheelbits = 0;
153 while (callwheelsize < ncallout) {
154 callwheelsize <<= 1;
155 ++callwheelbits;
156 }
157 callwheelmask = callwheelsize - 1;
984263bc 158
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159 /*
160 * Initialize per-cpu data structures.
161 */
162 for (cpu = 0; cpu < ncpus; ++cpu) {
163 softclock_pcpu_t sc;
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164
165 sc = &softclock_pcpu_ary[cpu];
166
77652cad 167 sc->callwheel = kmalloc(sizeof(*sc->callwheel) * callwheelsize,
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168 M_CALLOUT, M_WAITOK|M_ZERO);
169 for (i = 0; i < callwheelsize; ++i)
170 TAILQ_INIT(&sc->callwheel[i]);
171
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172 /*
173 * Create a preemption-capable thread for each cpu to handle
174 * softclock timeouts on that cpu. The preemption can only
175 * be blocked by a critical section. The thread can itself
176 * be preempted by normal interrupts.
177 */
178 lwkt_create(softclock_handler, sc, NULL,
abb6f10a 179 &sc->thread, TDF_STOPREQ|TDF_INTTHREAD, cpu,
92b561b7 180 "softclock %d", cpu);
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181#if 0
182 /*
183 * Do not make the thread preemptable until we clean up all
184 * the splsoftclock() calls in the system. Since the threads
185 * are no longer operated as a software interrupt, the
186 * splsoftclock() calls will not have any effect on them.
187 */
188 sc->thread.td_preemptable = lwkt_preempt;
189#endif
190 }
191}
192
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193/*
194 * Must occur after ncpus has been initialized.
195 */
196SYSINIT(softclock_setup, SI_SUB_CPU, SI_ORDER_SECOND, swi_softclock_setup, NULL);
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197
198/*
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199 * This routine is called from the hardclock() (basically a FASTint/IPI) on
200 * each cpu in the system. sc->curticks is this cpu's notion of the timebase.
201 * It IS NOT NECESSARILY SYNCHRONIZED WITH 'ticks'! sc->softticks is where
202 * the callwheel is currently indexed.
203 *
204 * WARNING! The MP lock is not necessarily held on call, nor can it be
205 * safely obtained.
206 *
207 * sc->softticks is adjusted by either this routine or our helper thread
208 * depending on whether the helper thread is running or not.
984263bc 209 */
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210void
211hardclock_softtick(globaldata_t gd)
212{
213 softclock_pcpu_t sc;
214
215 sc = &softclock_pcpu_ary[gd->gd_cpuid];
216 ++sc->curticks;
217 if (sc->isrunning)
218 return;
219 if (sc->softticks == sc->curticks) {
220 /*
221 * in sync, only wakeup the thread if there is something to
222 * do.
223 */
224 if (TAILQ_FIRST(&sc->callwheel[sc->softticks & callwheelmask]))
225 {
226 sc->isrunning = 1;
227 lwkt_schedule(&sc->thread);
228 } else {
229 ++sc->softticks;
230 }
231 } else {
232 /*
233 * out of sync, wakeup the thread unconditionally so it can
234 * catch up.
235 */
236 sc->isrunning = 1;
237 lwkt_schedule(&sc->thread);
238 }
239}
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240
241/*
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242 * This procedure is the main loop of our per-cpu helper thread. The
243 * sc->isrunning flag prevents us from racing hardclock_softtick() and
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244 * a critical section is sufficient to interlock sc->curticks and protect
245 * us from remote IPI's / list removal.
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246 *
247 * The thread starts with the MP lock held and not in a critical section.
248 * The loop itself is MP safe while individual callbacks may or may not
249 * be, so we obtain or release the MP lock as appropriate.
984263bc 250 */
ef0fdad1 251static void
92b561b7 252softclock_handler(void *arg)
984263bc 253{
92b561b7 254 softclock_pcpu_t sc;
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255 struct callout *c;
256 struct callout_tailq *bucket;
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257 void (*c_func)(void *);
258 void *c_arg;
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259#ifdef SMP
260 int mpsafe = 0;
261#endif
262
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263 lwkt_setpri_self(TDPRI_SOFT_NORM);
264
92b561b7 265 sc = arg;
88c4d2f6 266 crit_enter();
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267loop:
268 while (sc->softticks != (int)(sc->curticks + 1)) {
269 bucket = &sc->callwheel[sc->softticks & callwheelmask];
270
271 for (c = TAILQ_FIRST(bucket); c; c = sc->next) {
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272 if (c->c_time != sc->softticks) {
273 sc->next = TAILQ_NEXT(c, c_links.tqe);
92b561b7 274 continue;
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275 }
276#ifdef SMP
277 if (c->c_flags & CALLOUT_MPSAFE) {
278 if (mpsafe == 0) {
279 mpsafe = 1;
280 rel_mplock();
281 }
282 } else {
283 /*
284 * The request might be removed while we
285 * are waiting to get the MP lock. If it
286 * was removed sc->next will point to the
287 * next valid request or NULL, loop up.
288 */
289 if (mpsafe) {
290 mpsafe = 0;
291 sc->next = c;
292 get_mplock();
293 if (c != sc->next)
294 continue;
295 }
296 }
297#endif
298 sc->next = TAILQ_NEXT(c, c_links.tqe);
92b561b7 299 TAILQ_REMOVE(bucket, c, c_links.tqe);
4ac1a4cd 300
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301 c_func = c->c_func;
302 c_arg = c->c_arg;
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303 c->c_func = NULL;
304 KKASSERT(c->c_flags & CALLOUT_DID_INIT);
7eb3b2ae 305 c->c_flags &= ~CALLOUT_PENDING;
92b561b7 306 crit_exit();
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307 c_func(c_arg);
308 crit_enter();
309 /* NOTE: list may have changed */
984263bc 310 }
92b561b7 311 ++sc->softticks;
984263bc 312 }
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313 sc->isrunning = 0;
314 lwkt_deschedule_self(&sc->thread); /* == curthread */
315 lwkt_switch();
316 goto loop;
317 /* NOT REACHED */
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318}
319
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320#if 0
321
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322/*
323 * timeout --
324 * Execute a function after a specified length of time.
325 *
326 * untimeout --
327 * Cancel previous timeout function call.
328 *
329 * callout_handle_init --
330 * Initialize a handle so that using it with untimeout is benign.
331 *
332 * See AT&T BCI Driver Reference Manual for specification. This
333 * implementation differs from that one in that although an
334 * identification value is returned from timeout, the original
335 * arguments to timeout as well as the identifier are used to
336 * identify entries for untimeout.
337 */
338struct callout_handle
216ffe3f 339timeout(timeout_t *ftn, void *arg, int to_ticks)
984263bc 340{
92b561b7 341 softclock_pcpu_t sc;
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342 struct callout *new;
343 struct callout_handle handle;
344
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345 sc = &softclock_pcpu_ary[mycpu->gd_cpuid];
346 crit_enter();
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347
348 /* Fill in the next free callout structure. */
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349 new = SLIST_FIRST(&sc->callfree);
350 if (new == NULL) {
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351 /* XXX Attempt to malloc first */
352 panic("timeout table full");
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353 }
354 SLIST_REMOVE_HEAD(&sc->callfree, c_links.sle);
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355
356 callout_reset(new, to_ticks, ftn, arg);
357
358 handle.callout = new;
92b561b7 359 crit_exit();
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360 return (handle);
361}
362
363void
216ffe3f 364untimeout(timeout_t *ftn, void *arg, struct callout_handle handle)
984263bc 365{
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366 /*
367 * Check for a handle that was initialized
368 * by callout_handle_init, but never used
369 * for a real timeout.
370 */
371 if (handle.callout == NULL)
372 return;
373
92b561b7 374 crit_enter();
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375 if (handle.callout->c_func == ftn && handle.callout->c_arg == arg)
376 callout_stop(handle.callout);
92b561b7 377 crit_exit();
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378}
379
380void
381callout_handle_init(struct callout_handle *handle)
382{
383 handle->callout = NULL;
384}
385
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386#endif
387
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388/*
389 * New interface; clients allocate their own callout structures.
390 *
391 * callout_reset() - establish or change a timeout
392 * callout_stop() - disestablish a timeout
393 * callout_init() - initialize a callout structure so that it can
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394 * safely be passed to callout_reset() and callout_stop()
395 * callout_init_mp() - same but any installed functions must be MP safe.
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396 *
397 * <sys/callout.h> defines three convenience macros:
398 *
399 * callout_active() - returns truth if callout has not been serviced
400 * callout_pending() - returns truth if callout is still waiting for timeout
401 * callout_deactivate() - marks the callout as having been serviced
402 */
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403
404/*
405 * Start or restart a timeout. Install the callout structure in the
406 * callwheel. Callers may legally pass any value, even if 0 or negative,
407 * but since the sc->curticks index may have already been processed a
408 * minimum timeout of 1 tick will be enforced.
409 *
410 * The callout is installed on and will be processed on the current cpu's
411 * callout wheel.
412 */
984263bc 413void
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414callout_reset(struct callout *c, int to_ticks, void (*ftn)(void *),
415 void *arg)
984263bc 416{
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417 softclock_pcpu_t sc;
418 globaldata_t gd;
419
420#ifdef INVARIANTS
421 if ((c->c_flags & CALLOUT_DID_INIT) == 0) {
422 callout_init(c);
6ea70f76 423 kprintf(
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424 "callout_reset(%p) from %p: callout was not initialized\n",
425 c, ((int **)&c)[-1]);
426#ifdef DDB
427 db_print_backtrace();
428#endif
429 }
430#endif
431 gd = mycpu;
432 sc = &softclock_pcpu_ary[gd->gd_cpuid];
433 crit_enter_gd(gd);
984263bc 434
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435 if (c->c_flags & CALLOUT_PENDING)
436 callout_stop(c);
437
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438 if (to_ticks <= 0)
439 to_ticks = 1;
440
441 c->c_arg = arg;
442 c->c_flags |= (CALLOUT_ACTIVE | CALLOUT_PENDING);
443 c->c_func = ftn;
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444 c->c_time = sc->curticks + to_ticks;
445#ifdef SMP
446 c->c_gd = gd;
447#endif
448
449 TAILQ_INSERT_TAIL(&sc->callwheel[c->c_time & callwheelmask],
984263bc 450 c, c_links.tqe);
92b561b7 451 crit_exit_gd(gd);
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452}
453
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454/*
455 * Stop a running timer. WARNING! If called on a cpu other then the one
456 * the callout was started on this function will liveloop on its IPI to
457 * the target cpu to process the request. It is possible for the callout
458 * to execute in that case.
459 *
460 * WARNING! This routine may be called from an IPI
461 */
984263bc 462int
216ffe3f 463callout_stop(struct callout *c)
984263bc 464{
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465 globaldata_t gd = mycpu;
466#ifdef SMP
467 globaldata_t tgd;
468#endif
469 softclock_pcpu_t sc;
470
471#ifdef INVARIANTS
472 if ((c->c_flags & CALLOUT_DID_INIT) == 0) {
473 callout_init(c);
6ea70f76 474 kprintf(
634056cf 475 "callout_stop(%p) from %p: callout was not initialized\n",
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476 c, ((int **)&c)[-1]);
477#ifdef DDB
478 db_print_backtrace();
479#endif
480 }
481#endif
482 crit_enter_gd(gd);
984263bc 483
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484 /*
485 * Don't attempt to delete a callout that's not on the queue.
486 */
92b561b7 487 if ((c->c_flags & CALLOUT_PENDING) == 0) {
984263bc 488 c->c_flags &= ~CALLOUT_ACTIVE;
92b561b7 489 crit_exit_gd(gd);
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490 return (0);
491 }
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492#ifdef SMP
493 if ((tgd = c->c_gd) != gd) {
494 /*
495 * If the callout is owned by a different CPU we have to
496 * execute the function synchronously on the target cpu.
497 */
498 int seq;
499
35238fa5 500 cpu_ccfence(); /* don't let tgd alias c_gd */
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501 seq = lwkt_send_ipiq(tgd, (void *)callout_stop, c);
502 lwkt_wait_ipiq(tgd, seq);
503 } else
504#endif
505 {
506 /*
507 * If the callout is owned by the same CPU we can
508 * process it directly, but if we are racing our helper
509 * thread (sc->next), we have to adjust sc->next. The
510 * race is interlocked by a critical section.
511 */
512 sc = &softclock_pcpu_ary[gd->gd_cpuid];
984263bc 513
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514 c->c_flags &= ~(CALLOUT_ACTIVE | CALLOUT_PENDING);
515 if (sc->next == c)
516 sc->next = TAILQ_NEXT(c, c_links.tqe);
517
518 TAILQ_REMOVE(&sc->callwheel[c->c_time & callwheelmask],
519 c, c_links.tqe);
520 c->c_func = NULL;
984263bc 521 }
92b561b7 522 crit_exit_gd(gd);
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523 return (1);
524}
525
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526/*
527 * Prepare a callout structure for use by callout_reset() and/or
528 * callout_stop(). The MP version of this routine requires that the callback
986d8a07 529 * function installed by callout_reset() be MP safe.
92b561b7 530 */
984263bc 531void
216ffe3f 532callout_init(struct callout *c)
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533{
534 bzero(c, sizeof *c);
92b561b7 535 c->c_flags = CALLOUT_DID_INIT;
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536}
537
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538void
539callout_init_mp(struct callout *c)
ef0fdad1 540{
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541 callout_init(c);
542 c->c_flags |= CALLOUT_MPSAFE;
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543}
544
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545/* What, are you joking? This is nuts! -Matt */
546#if 0
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547#ifdef APM_FIXUP_CALLTODO
548/*
549 * Adjust the kernel calltodo timeout list. This routine is used after
550 * an APM resume to recalculate the calltodo timer list values with the
551 * number of hz's we have been sleeping. The next hardclock() will detect
552 * that there are fired timers and run softclock() to execute them.
553 *
554 * Please note, I have not done an exhaustive analysis of what code this
555 * might break. I am motivated to have my select()'s and alarm()'s that
556 * have expired during suspend firing upon resume so that the applications
557 * which set the timer can do the maintanence the timer was for as close
558 * as possible to the originally intended time. Testing this code for a
559 * week showed that resuming from a suspend resulted in 22 to 25 timers
560 * firing, which seemed independant on whether the suspend was 2 hours or
561 * 2 days. Your milage may vary. - Ken Key <key@cs.utk.edu>
562 */
563void
216ffe3f 564adjust_timeout_calltodo(struct timeval *time_change)
984263bc 565{
1fd87d54 566 struct callout *p;
984263bc 567 unsigned long delta_ticks;
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568
569 /*
570 * How many ticks were we asleep?
571 * (stolen from tvtohz()).
572 */
573
574 /* Don't do anything */
575 if (time_change->tv_sec < 0)
576 return;
577 else if (time_change->tv_sec <= LONG_MAX / 1000000)
578 delta_ticks = (time_change->tv_sec * 1000000 +
579 time_change->tv_usec + (tick - 1)) / tick + 1;
580 else if (time_change->tv_sec <= LONG_MAX / hz)
581 delta_ticks = time_change->tv_sec * hz +
582 (time_change->tv_usec + (tick - 1)) / tick + 1;
583 else
584 delta_ticks = LONG_MAX;
585
586 if (delta_ticks > INT_MAX)
587 delta_ticks = INT_MAX;
588
589 /*
590 * Now rip through the timer calltodo list looking for timers
591 * to expire.
592 */
593
594 /* don't collide with softclock() */
e43a034f 595 crit_enter();
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596 for (p = calltodo.c_next; p != NULL; p = p->c_next) {
597 p->c_time -= delta_ticks;
598
599 /* Break if the timer had more time on it than delta_ticks */
600 if (p->c_time > 0)
601 break;
602
603 /* take back the ticks the timer didn't use (p->c_time <= 0) */
604 delta_ticks = -p->c_time;
605 }
e43a034f 606 crit_exit();
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607
608 return;
609}
610#endif /* APM_FIXUP_CALLTODO */
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611#endif
612