vkernel - Fix corrupt tailq (vkernel64 only)
[dragonfly.git] / sys / kern / kern_synch.c
CommitLineData
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1/*-
2 * Copyright (c) 1982, 1986, 1990, 1991, 1993
3 * The Regents of the University of California. All rights reserved.
4 * (c) UNIX System Laboratories, Inc.
5 * All or some portions of this file are derived from material licensed
6 * to the University of California by American Telephone and Telegraph
7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
8 * the permission of UNIX System Laboratories, Inc.
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 * 3. All advertising materials mentioning features or use of this software
19 * must display the following acknowledgement:
20 * This product includes software developed by the University of
21 * California, Berkeley and its contributors.
22 * 4. Neither the name of the University nor the names of its contributors
23 * may be used to endorse or promote products derived from this software
24 * without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 * SUCH DAMAGE.
37 *
38 * @(#)kern_synch.c 8.9 (Berkeley) 5/19/95
39 * $FreeBSD: src/sys/kern/kern_synch.c,v 1.87.2.6 2002/10/13 07:29:53 kbyanc Exp $
c730be20 40 * $DragonFly: src/sys/kern/kern_synch.c,v 1.91 2008/09/09 04:06:13 dillon Exp $
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41 */
42
43#include "opt_ktrace.h"
44
45#include <sys/param.h>
46#include <sys/systm.h>
47#include <sys/proc.h>
48#include <sys/kernel.h>
49#include <sys/signalvar.h>
50#include <sys/resourcevar.h>
51#include <sys/vmmeter.h>
52#include <sys/sysctl.h>
344ad853 53#include <sys/lock.h>
984263bc 54#include <sys/uio.h>
fc9ae81d 55#ifdef KTRACE
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56#include <sys/ktrace.h>
57#endif
f1d1c3fa 58#include <sys/xwait.h>
9afb0ffd 59#include <sys/ktr.h>
684a93c4 60#include <sys/serialize.h>
984263bc 61
684a93c4 62#include <sys/signal2.h>
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63#include <sys/thread2.h>
64#include <sys/spinlock2.h>
7f6220a9 65#include <sys/mutex2.h>
684a93c4 66#include <sys/mplock2.h>
bf765287 67
984263bc 68#include <machine/cpu.h>
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69#include <machine/smp.h>
70
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71TAILQ_HEAD(tslpque, thread);
72
402ed7e1 73static void sched_setup (void *dummy);
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74SYSINIT(sched_setup, SI_SUB_KICK_SCHEDULER, SI_ORDER_FIRST, sched_setup, NULL)
75
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76int hogticks;
77int lbolt;
344ad853 78int lbolt_syncer;
984263bc 79int sched_quantum; /* Roundrobin scheduling quantum in ticks. */
17a9f566 80int ncpus;
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81int ncpus2, ncpus2_shift, ncpus2_mask; /* note: mask not cpumask_t */
82int ncpus_fit, ncpus_fit_mask; /* note: mask not cpumask_t */
e43a034f 83int safepri;
dbcd0c9b 84int tsleep_now_works;
5ea440eb 85int tsleep_crypto_dump = 0;
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86
87static struct callout loadav_callout;
35f9d051 88static struct callout schedcpu_callout;
fc17ad60 89MALLOC_DEFINE(M_TSLEEP, "tslpque", "tsleep queues");
984263bc 90
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91#define __DEALL(ident) __DEQUALIFY(void *, ident)
92
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93#if !defined(KTR_TSLEEP)
94#define KTR_TSLEEP KTR_ALL
95#endif
96KTR_INFO_MASTER(tsleep);
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97KTR_INFO(KTR_TSLEEP, tsleep, tsleep_beg, 0, "tsleep enter %p", sizeof(void *));
98KTR_INFO(KTR_TSLEEP, tsleep, tsleep_end, 1, "tsleep exit", 0);
99KTR_INFO(KTR_TSLEEP, tsleep, wakeup_beg, 2, "wakeup enter %p", sizeof(void *));
100KTR_INFO(KTR_TSLEEP, tsleep, wakeup_end, 3, "wakeup exit", 0);
d9345d3a 101KTR_INFO(KTR_TSLEEP, tsleep, ilockfail, 4, "interlock failed %p", sizeof(void *));
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102
103#define logtsleep1(name) KTR_LOG(tsleep_ ## name)
104#define logtsleep2(name, val) KTR_LOG(tsleep_ ## name, val)
9afb0ffd 105
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106struct loadavg averunnable =
107 { {0, 0, 0}, FSCALE }; /* load average, of runnable procs */
108/*
109 * Constants for averages over 1, 5, and 15 minutes
110 * when sampling at 5 second intervals.
111 */
112static fixpt_t cexp[3] = {
113 0.9200444146293232 * FSCALE, /* exp(-1/12) */
114 0.9834714538216174 * FSCALE, /* exp(-1/60) */
115 0.9944598480048967 * FSCALE, /* exp(-1/180) */
116};
117
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118static void endtsleep (void *);
119static void loadav (void *arg);
402ed7e1 120static void schedcpu (void *arg);
ce4b5045 121#ifdef SMP
74c9628e 122static void tsleep_wakeup_remote(struct thread *td);
ce4b5045 123#endif
984263bc 124
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125/*
126 * Adjust the scheduler quantum. The quantum is specified in microseconds.
127 * Note that 'tick' is in microseconds per tick.
128 */
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129static int
130sysctl_kern_quantum(SYSCTL_HANDLER_ARGS)
131{
132 int error, new_val;
133
a591f597 134 new_val = sched_quantum * ustick;
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135 error = sysctl_handle_int(oidp, &new_val, 0, req);
136 if (error != 0 || req->newptr == NULL)
137 return (error);
a591f597 138 if (new_val < ustick)
984263bc 139 return (EINVAL);
a591f597 140 sched_quantum = new_val / ustick;
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141 hogticks = 2 * sched_quantum;
142 return (0);
143}
144
145SYSCTL_PROC(_kern, OID_AUTO, quantum, CTLTYPE_INT|CTLFLAG_RW,
146 0, sizeof sched_quantum, sysctl_kern_quantum, "I", "");
147
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148/*
149 * If `ccpu' is not equal to `exp(-1/20)' and you still want to use the
150 * faster/more-accurate formula, you'll have to estimate CCPU_SHIFT below
151 * and possibly adjust FSHIFT in "param.h" so that (FSHIFT >= CCPU_SHIFT).
152 *
153 * To estimate CCPU_SHIFT for exp(-1/20), the following formula was used:
dcc99b62 154 * 1 - exp(-1/20) ~= 0.0487 ~= 0.0488 == 1 (fixed pt, *11* bits).
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155 *
156 * If you don't want to bother with the faster/more-accurate formula, you
157 * can set CCPU_SHIFT to (FSHIFT + 1) which will use a slower/less-accurate
158 * (more general) method of calculating the %age of CPU used by a process.
dcc99b62 159 *
08f2f1bb 160 * decay 95% of `lwp_pctcpu' in 60 seconds; see CCPU_SHIFT before changing
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161 */
162#define CCPU_SHIFT 11
163
164static fixpt_t ccpu = 0.95122942450071400909 * FSCALE; /* exp(-1/20) */
165SYSCTL_INT(_kern, OID_AUTO, ccpu, CTLFLAG_RD, &ccpu, 0, "");
166
167/*
168 * kernel uses `FSCALE', userland (SHOULD) use kern.fscale
984263bc 169 */
460426e6 170int fscale __unused = FSCALE; /* exported to systat */
dcc99b62 171SYSCTL_INT(_kern, OID_AUTO, fscale, CTLFLAG_RD, 0, FSCALE, "");
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172
173/*
0a3f9b47 174 * Recompute process priorities, once a second.
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175 *
176 * Since the userland schedulers are typically event oriented, if the
177 * estcpu calculation at wakeup() time is not sufficient to make a
178 * process runnable relative to other processes in the system we have
179 * a 1-second recalc to help out.
180 *
181 * This code also allows us to store sysclock_t data in the process structure
182 * without fear of an overrun, since sysclock_t are guarenteed to hold
183 * several seconds worth of count.
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184 *
185 * WARNING! callouts can preempt normal threads. However, they will not
186 * preempt a thread holding a spinlock so we *can* safely use spinlocks.
984263bc 187 */
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188static int schedcpu_stats(struct proc *p, void *data __unused);
189static int schedcpu_resource(struct proc *p, void *data __unused);
190
984263bc 191static void
26a0694b 192schedcpu(void *arg)
984263bc 193{
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194 allproc_scan(schedcpu_stats, NULL);
195 allproc_scan(schedcpu_resource, NULL);
196 wakeup((caddr_t)&lbolt);
197 wakeup((caddr_t)&lbolt_syncer);
198 callout_reset(&schedcpu_callout, hz, schedcpu, NULL);
199}
200
201/*
202 * General process statistics once a second
203 */
204static int
205schedcpu_stats(struct proc *p, void *data __unused)
206{
08f2f1bb
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207 struct lwp *lp;
208
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209 crit_enter();
210 p->p_swtime++;
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211 FOREACH_LWP_IN_PROC(lp, p) {
212 if (lp->lwp_stat == LSSLEEP)
213 lp->lwp_slptime++;
4b5f931b 214
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215 /*
216 * Only recalculate processes that are active or have slept
217 * less then 2 seconds. The schedulers understand this.
218 */
219 if (lp->lwp_slptime <= 1) {
220 p->p_usched->recalculate(lp);
221 } else {
222 lp->lwp_pctcpu = (lp->lwp_pctcpu * ccpu) >> FSHIFT;
223 }
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224 }
225 crit_exit();
226 return(0);
227}
a46fac56 228
8fa76237 229/*
84204577 230 * Resource checks. XXX break out since ksignal/killproc can block,
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231 * limiting us to one process killed per second. There is probably
232 * a better way.
233 */
234static int
235schedcpu_resource(struct proc *p, void *data __unused)
236{
237 u_int64_t ttime;
08f2f1bb 238 struct lwp *lp;
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239
240 crit_enter();
241 if (p->p_stat == SIDL ||
416d05d7 242 p->p_stat == SZOMB ||
c7e98b2f 243 p->p_limit == NULL
8fa76237 244 ) {
e43a034f 245 crit_exit();
8fa76237 246 return(0);
984263bc 247 }
344ad853 248
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249 ttime = 0;
250 FOREACH_LWP_IN_PROC(lp, p) {
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251 /*
252 * We may have caught an lp in the middle of being
253 * created, lwp_thread can be NULL.
254 */
255 if (lp->lwp_thread) {
256 ttime += lp->lwp_thread->td_sticks;
257 ttime += lp->lwp_thread->td_uticks;
258 }
c7e98b2f 259 }
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260
261 switch(plimit_testcpulimit(p->p_limit, ttime)) {
262 case PLIMIT_TESTCPU_KILL:
263 killproc(p, "exceeded maximum CPU limit");
264 break;
265 case PLIMIT_TESTCPU_XCPU:
266 if ((p->p_flag & P_XCPU) == 0) {
267 p->p_flag |= P_XCPU;
84204577 268 ksignal(p, SIGXCPU);
344ad853 269 }
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270 break;
271 default:
c0b8a06d 272 break;
344ad853 273 }
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274 crit_exit();
275 return(0);
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276}
277
278/*
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279 * This is only used by ps. Generate a cpu percentage use over
280 * a period of one second.
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281 *
282 * MPSAFE
984263bc 283 */
dcc99b62 284void
553ea3c8 285updatepcpu(struct lwp *lp, int cpticks, int ttlticks)
984263bc 286{
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287 fixpt_t acc;
288 int remticks;
289
290 acc = (cpticks << FSHIFT) / ttlticks;
291 if (ttlticks >= ESTCPUFREQ) {
553ea3c8 292 lp->lwp_pctcpu = acc;
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293 } else {
294 remticks = ESTCPUFREQ - ttlticks;
553ea3c8 295 lp->lwp_pctcpu = (acc * ttlticks + lp->lwp_pctcpu * remticks) /
dcc99b62 296 ESTCPUFREQ;
a46fac56 297 }
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298}
299
300/*
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301 * tsleep/wakeup hash table parameters. Try to find the sweet spot for
302 * like addresses being slept on.
984263bc 303 */
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304#define TABLESIZE 1024
305#define LOOKUP(x) (((intptr_t)(x) >> 6) & (TABLESIZE - 1))
984263bc 306
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307static cpumask_t slpque_cpumasks[TABLESIZE];
308
984263bc 309/*
a46fac56 310 * General scheduler initialization. We force a reschedule 25 times
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311 * a second by default. Note that cpu0 is initialized in early boot and
312 * cannot make any high level calls.
313 *
314 * Each cpu has its own sleep queue.
984263bc 315 */
984263bc 316void
fc17ad60 317sleep_gdinit(globaldata_t gd)
984263bc 318{
fc17ad60 319 static struct tslpque slpque_cpu0[TABLESIZE];
9c1fad94 320 int i;
984263bc 321
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322 if (gd->gd_cpuid == 0) {
323 sched_quantum = (hz + 24) / 25;
324 hogticks = 2 * sched_quantum;
325
326 gd->gd_tsleep_hash = slpque_cpu0;
327 } else {
77652cad 328 gd->gd_tsleep_hash = kmalloc(sizeof(slpque_cpu0),
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329 M_TSLEEP, M_WAITOK | M_ZERO);
330 }
331 for (i = 0; i < TABLESIZE; ++i)
332 TAILQ_INIT(&gd->gd_tsleep_hash[i]);
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333}
334
335/*
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336 * This is a dandy function that allows us to interlock tsleep/wakeup
337 * operations with unspecified upper level locks, such as lockmgr locks,
338 * simply by holding a critical section. The sequence is:
339 *
340 * (acquire upper level lock)
341 * tsleep_interlock(blah)
342 * (release upper level lock)
343 * tsleep(blah, ...)
344 *
345 * Basically this functions queues us on the tsleep queue without actually
346 * descheduling us. When tsleep() is later called with PINTERLOCK it
347 * assumes the thread was already queued, otherwise it queues it there.
348 *
349 * Thus it is possible to receive the wakeup prior to going to sleep and
350 * the race conditions are covered.
351 */
352static __inline void
5decebc7 353_tsleep_interlock(globaldata_t gd, const volatile void *ident, int flags)
ae8e83e6
MD
354{
355 thread_t td = gd->gd_curthread;
356 int id;
357
358 crit_enter_quick(td);
359 if (td->td_flags & TDF_TSLEEPQ) {
360 id = LOOKUP(td->td_wchan);
361 TAILQ_REMOVE(&gd->gd_tsleep_hash[id], td, td_sleepq);
362 if (TAILQ_FIRST(&gd->gd_tsleep_hash[id]) == NULL)
da23a592 363 atomic_clear_cpumask(&slpque_cpumasks[id], gd->gd_cpumask);
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364 } else {
365 td->td_flags |= TDF_TSLEEPQ;
366 }
367 id = LOOKUP(ident);
368 TAILQ_INSERT_TAIL(&gd->gd_tsleep_hash[id], td, td_sleepq);
da23a592 369 atomic_set_cpumask(&slpque_cpumasks[id], gd->gd_cpumask);
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370 td->td_wchan = ident;
371 td->td_wdomain = flags & PDOMAIN_MASK;
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372 crit_exit_quick(td);
373}
374
375void
5decebc7 376tsleep_interlock(const volatile void *ident, int flags)
ae8e83e6
MD
377{
378 _tsleep_interlock(mycpu, ident, flags);
379}
380
381/*
382 * Remove thread from sleepq. Must be called with a critical section held.
383 */
384static __inline void
385_tsleep_remove(thread_t td)
386{
387 globaldata_t gd = mycpu;
388 int id;
389
390 KKASSERT(td->td_gd == gd);
391 if (td->td_flags & TDF_TSLEEPQ) {
392 td->td_flags &= ~TDF_TSLEEPQ;
393 id = LOOKUP(td->td_wchan);
394 TAILQ_REMOVE(&gd->gd_tsleep_hash[id], td, td_sleepq);
395 if (TAILQ_FIRST(&gd->gd_tsleep_hash[id]) == NULL)
da23a592 396 atomic_clear_cpumask(&slpque_cpumasks[id], gd->gd_cpumask);
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397 td->td_wchan = NULL;
398 td->td_wdomain = 0;
399 }
400}
401
402void
403tsleep_remove(thread_t td)
404{
405 _tsleep_remove(td);
406}
407
408/*
409 * This function removes a thread from the tsleep queue and schedules
410 * it. This function may act asynchronously. The target thread may be
411 * sleeping on a different cpu.
412 *
413 * This function mus be called while in a critical section but if the
414 * target thread is sleeping on a different cpu we cannot safely probe
415 * td_flags.
74c9628e
MD
416 *
417 * This function is only called from a different cpu via setrunnable()
418 * when the thread is in a known sleep. However, multiple wakeups are
419 * possible and we must hold the td to prevent a race against the thread
420 * exiting.
ae8e83e6
MD
421 */
422static __inline
423void
424_tsleep_wakeup(struct thread *td)
425{
c4e34360 426#ifdef SMP
ae8e83e6
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427 globaldata_t gd = mycpu;
428
ae8e83e6 429 if (td->td_gd != gd) {
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430 lwkt_hold(td);
431 lwkt_send_ipiq(td->td_gd, (ipifunc1_t)tsleep_wakeup_remote, td);
ae8e83e6
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432 return;
433 }
434#endif
435 _tsleep_remove(td);
436 if (td->td_flags & TDF_TSLEEP_DESCHEDULED) {
437 td->td_flags &= ~TDF_TSLEEP_DESCHEDULED;
438 lwkt_schedule(td);
439 }
440}
441
ce4b5045 442#ifdef SMP
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443static
444void
74c9628e 445tsleep_wakeup_remote(struct thread *td)
ae8e83e6
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446{
447 _tsleep_wakeup(td);
74c9628e 448 lwkt_rele(td);
ae8e83e6 449}
ce4b5045 450#endif
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451
452
453/*
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454 * General sleep call. Suspends the current process until a wakeup is
455 * performed on the specified identifier. The process will then be made
456 * runnable with the specified priority. Sleeps at most timo/hz seconds
377d4740 457 * (0 means no timeout). If flags includes PCATCH flag, signals are checked
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458 * before and after sleeping, else signals are not checked. Returns 0 if
459 * awakened, EWOULDBLOCK if the timeout expires. If PCATCH is set and a
460 * signal needs to be delivered, ERESTART is returned if the current system
461 * call should be restarted if possible, and EINTR is returned if the system
462 * call should be interrupted by the signal (return EINTR).
26a0694b 463 *
0a3f9b47
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464 * Note that if we are a process, we release_curproc() before messing with
465 * the LWKT scheduler.
a46fac56
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466 *
467 * During autoconfiguration or after a panic, a sleep will simply
468 * lower the priority briefly to allow interrupts, then return.
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469 */
470int
5decebc7 471tsleep(const volatile void *ident, int flags, const char *wmesg, int timo)
984263bc 472{
dadab5e9 473 struct thread *td = curthread;
08f2f1bb 474 struct lwp *lp = td->td_lwp;
0cfcada1 475 struct proc *p = td->td_proc; /* may be NULL */
fc17ad60 476 globaldata_t gd;
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477 int sig;
478 int catch;
479 int id;
480 int error;
e43a034f 481 int oldpri;
076fecef 482 struct callout thandle;
984263bc 483
0cfcada1
MD
484 /*
485 * NOTE: removed KTRPOINT, it could cause races due to blocking
486 * even in stable. Just scrap it for now.
487 */
5ea440eb 488 if (!tsleep_crypto_dump && (tsleep_now_works == 0 || panicstr)) {
984263bc 489 /*
dbcd0c9b
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490 * After a panic, or before we actually have an operational
491 * softclock, just give interrupts a chance, then just return;
492 *
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493 * don't run any other procs or panic below,
494 * in case this is the idle process and already asleep.
495 */
e43a034f 496 splz();
f9235b6d 497 oldpri = td->td_pri;
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498 lwkt_setpri_self(safepri);
499 lwkt_switch();
500 lwkt_setpri_self(oldpri);
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501 return (0);
502 }
8aa3430c 503 logtsleep2(tsleep_beg, ident);
fc17ad60
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504 gd = td->td_gd;
505 KKASSERT(td != &gd->gd_idlethread); /* you must be kidding! */
344ad853
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506
507 /*
508 * NOTE: all of this occurs on the current cpu, including any
509 * callout-based wakeups, so a critical section is a sufficient
510 * interlock.
511 *
512 * The entire sequence through to where we actually sleep must
513 * run without breaking the critical section.
514 */
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MD
515 catch = flags & PCATCH;
516 error = 0;
517 sig = 0;
518
37af14fe 519 crit_enter_quick(td);
344ad853 520
0cfcada1 521 KASSERT(ident != NULL, ("tsleep: no ident"));
7278a846
SS
522 KASSERT(lp == NULL ||
523 lp->lwp_stat == LSRUN || /* Obvious */
524 lp->lwp_stat == LSSTOP, /* Set in tstop */
525 ("tsleep %p %s %d",
526 ident, wmesg, lp->lwp_stat));
0cfcada1 527
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528 /*
529 * Setup for the current process (if this is a process).
530 */
08f2f1bb 531 if (lp) {
344ad853
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532 if (catch) {
533 /*
534 * Early termination if PCATCH was set and a
535 * signal is pending, interlocked with the
536 * critical section.
537 *
538 * Early termination only occurs when tsleep() is
164b8401 539 * entered while in a normal LSRUN state.
344ad853 540 */
08f2f1bb 541 if ((sig = CURSIG(lp)) != 0)
344ad853
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542 goto resume;
543
544 /*
7c1212ec
MD
545 * Early termination if PCATCH was set and a
546 * mailbox signal was possibly delivered prior to
547 * the system call even being made, in order to
548 * allow the user to interlock without having to
549 * make additional system calls.
550 */
551 if (p->p_flag & P_MAILBOX)
552 goto resume;
553
554 /*
84204577 555 * Causes ksignal to wake us up when.
344ad853 556 */
9a379a4a 557 lp->lwp_flag |= LWP_SINTR;
344ad853 558 }
4ecd8190 559 }
344ad853 560
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MD
561 /*
562 * We interlock the sleep queue if the caller has not already done
563 * it for us.
564 */
565 if ((flags & PINTERLOCKED) == 0) {
566 id = LOOKUP(ident);
567 _tsleep_interlock(gd, ident, flags);
568 }
569
570 /*
571 *
572 * If no interlock was set we do an integrated interlock here.
573 * Make sure the current process has been untangled from
574 * the userland scheduler and initialize slptime to start
575 * counting. We must interlock the sleep queue before doing
576 * this to avoid wakeup/process-ipi races which can occur under
577 * heavy loads.
578 */
579 if (lp) {
08f2f1bb
SS
580 p->p_usched->release_curproc(lp);
581 lp->lwp_slptime = 0;
0a3f9b47 582 }
fc17ad60
MD
583
584 /*
d9345d3a
MD
585 * If the interlocked flag is set but our cpu bit in the slpqueue
586 * is no longer set, then a wakeup was processed inbetween the
4ecd8190
MD
587 * tsleep_interlock() (ours or the callers), and here. This can
588 * occur under numerous circumstances including when we release the
589 * current process.
d9345d3a 590 *
4ecd8190
MD
591 * Extreme loads can cause the sending of an IPI (e.g. wakeup()'s)
592 * to process incoming IPIs, thus draining incoming wakeups.
d9345d3a 593 */
4ecd8190
MD
594 if ((td->td_flags & TDF_TSLEEPQ) == 0) {
595 logtsleep2(ilockfail, ident);
596 goto resume;
d9345d3a 597 }
4ecd8190
MD
598
599 /*
600 * scheduling is blocked while in a critical section. Coincide
601 * the descheduled-by-tsleep flag with the descheduling of the
602 * lwkt.
603 */
37af14fe 604 lwkt_deschedule_self(td);
ae8e83e6 605 td->td_flags |= TDF_TSLEEP_DESCHEDULED;
344ad853 606 td->td_wmesg = wmesg;
344ad853
MD
607
608 /*
609 * Setup the timeout, if any
610 */
076fecef
MD
611 if (timo) {
612 callout_init(&thandle);
613 callout_reset(&thandle, timo, endtsleep, td);
614 }
344ad853 615
984263bc 616 /*
344ad853 617 * Beddy bye bye.
984263bc 618 */
08f2f1bb 619 if (lp) {
26a0694b 620 /*
52eedfb5 621 * Ok, we are sleeping. Place us in the SSLEEP state.
26a0694b 622 */
9388413d 623 KKASSERT((lp->lwp_flag & LWP_ONRUNQ) == 0);
7278a846
SS
624 /*
625 * tstop() sets LSSTOP, so don't fiddle with that.
626 */
627 if (lp->lwp_stat != LSSTOP)
628 lp->lwp_stat = LSSLEEP;
08f2f1bb 629 lp->lwp_ru.ru_nvcsw++;
344ad853 630 lwkt_switch();
ab554892
MD
631
632 /*
164b8401 633 * And when we are woken up, put us back in LSRUN. If we
ab554892
MD
634 * slept for over a second, recalculate our estcpu.
635 */
164b8401 636 lp->lwp_stat = LSRUN;
08f2f1bb
SS
637 if (lp->lwp_slptime)
638 p->p_usched->recalculate(lp);
639 lp->lwp_slptime = 0;
0cfcada1
MD
640 } else {
641 lwkt_switch();
642 }
344ad853 643
fc17ad60
MD
644 /*
645 * Make sure we haven't switched cpus while we were asleep. It's
344ad853 646 * not supposed to happen. Cleanup our temporary flags.
fc17ad60
MD
647 */
648 KKASSERT(gd == td->td_gd);
344ad853
MD
649
650 /*
651 * Cleanup the timeout.
652 */
653 if (timo) {
654 if (td->td_flags & TDF_TIMEOUT) {
655 td->td_flags &= ~TDF_TIMEOUT;
a40da8f0 656 error = EWOULDBLOCK;
344ad853
MD
657 } else {
658 callout_stop(&thandle);
659 }
0cfcada1 660 }
344ad853
MD
661
662 /*
ae8e83e6
MD
663 * Make sure we have been removed from the sleepq. This should
664 * have been done for us already.
f022a370
MD
665 *
666 * However, it is possible for a scheduling IPI to be in flight
667 * from a previous tsleep/tsleep_interlock or due to a straight-out
668 * call to lwkt_schedule() (in the case of an interrupt thread).
669 * So don't complain if DESCHEDULED is still set.
344ad853 670 */
ae8e83e6 671 _tsleep_remove(td);
344ad853 672 td->td_wmesg = NULL;
ae8e83e6
MD
673 if (td->td_flags & TDF_TSLEEP_DESCHEDULED) {
674 td->td_flags &= ~TDF_TSLEEP_DESCHEDULED;
ae8e83e6 675 }
344ad853
MD
676
677 /*
7c1212ec
MD
678 * Figure out the correct error return. If interrupted by a
679 * signal we want to return EINTR or ERESTART.
680 *
681 * If P_MAILBOX is set no automatic system call restart occurs
682 * and we return EINTR. P_MAILBOX is meant to be used as an
683 * interlock, the user must poll it prior to any system call
684 * that it wishes to interlock a mailbox signal against since
685 * the flag is cleared on *any* system call that sleeps.
344ad853
MD
686 */
687resume:
0cfcada1 688 if (p) {
7c1212ec
MD
689 if (catch && error == 0) {
690 if ((p->p_flag & P_MAILBOX) && sig == 0) {
344ad853 691 error = EINTR;
08f2f1bb 692 } else if (sig != 0 || (sig = CURSIG(lp))) {
7c1212ec
MD
693 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig))
694 error = EINTR;
695 else
696 error = ERESTART;
697 }
984263bc 698 }
9a379a4a
SS
699 lp->lwp_flag &= ~(LWP_BREAKTSLEEP | LWP_SINTR);
700 p->p_flag &= ~P_MAILBOX;
984263bc 701 }
8aa3430c 702 logtsleep1(tsleep_end);
344ad853
MD
703 crit_exit_quick(td);
704 return (error);
984263bc
MD
705}
706
984263bc 707/*
bf765287 708 * Interlocked spinlock sleep. An exclusively held spinlock must
e590ee86 709 * be passed to ssleep(). The function will atomically release the
bf765287
MD
710 * spinlock and tsleep on the ident, then reacquire the spinlock and
711 * return.
712 *
713 * This routine is fairly important along the critical path, so optimize it
714 * heavily.
715 */
716int
5decebc7 717ssleep(const volatile void *ident, struct spinlock *spin, int flags,
bf765287
MD
718 const char *wmesg, int timo)
719{
720 globaldata_t gd = mycpu;
721 int error;
16523a43 722
ae8e83e6 723 _tsleep_interlock(gd, ident, flags);
7cfe2b28 724 spin_unlock_quick(gd, spin);
ef48be0d 725 error = tsleep(ident, flags | PINTERLOCKED, wmesg, timo);
7cfe2b28 726 spin_lock_quick(gd, spin);
bf765287
MD
727
728 return (error);
16523a43
MD
729}
730
bed060de 731int
5decebc7
MD
732lksleep(const volatile void *ident, struct lock *lock, int flags,
733 const char *wmesg, int timo)
bed060de
AH
734{
735 globaldata_t gd = mycpu;
736 int error;
737
738 _tsleep_interlock(gd, ident, flags);
739 lockmgr(lock, LK_RELEASE);
740 error = tsleep(ident, flags | PINTERLOCKED, wmesg, timo);
741 lockmgr(lock, LK_EXCLUSIVE);
742
743 return (error);
744}
745
16523a43 746/*
7f6220a9
MD
747 * Interlocked mutex sleep. An exclusively held mutex must be passed
748 * to mtxsleep(). The function will atomically release the mutex
749 * and tsleep on the ident, then reacquire the mutex and return.
750 */
751int
5decebc7 752mtxsleep(const volatile void *ident, struct mtx *mtx, int flags,
7f6220a9
MD
753 const char *wmesg, int timo)
754{
755 globaldata_t gd = mycpu;
756 int error;
757
758 _tsleep_interlock(gd, ident, flags);
759 mtx_unlock(mtx);
760 error = tsleep(ident, flags | PINTERLOCKED, wmesg, timo);
761 mtx_lock_ex_quick(mtx, wmesg);
762
763 return (error);
764}
765
766/*
362e59be 767 * Interlocked serializer sleep. An exclusively held serializer must
ed3f6624 768 * be passed to zsleep(). The function will atomically release
362e59be
SZ
769 * the serializer and tsleep on the ident, then reacquire the serializer
770 * and return.
771 */
772int
5decebc7 773zsleep(const volatile void *ident, struct lwkt_serialize *slz, int flags,
ed3f6624 774 const char *wmesg, int timo)
362e59be 775{
ae8e83e6 776 globaldata_t gd = mycpu;
362e59be
SZ
777 int ret;
778
779 ASSERT_SERIALIZED(slz);
780
ae8e83e6 781 _tsleep_interlock(gd, ident, flags);
362e59be 782 lwkt_serialize_exit(slz);
ef48be0d 783 ret = tsleep(ident, flags | PINTERLOCKED, wmesg, timo);
362e59be 784 lwkt_serialize_enter(slz);
362e59be
SZ
785
786 return ret;
787}
788
789/*
a22c590e
MD
790 * Directly block on the LWKT thread by descheduling it. This
791 * is much faster then tsleep(), but the only legal way to wake
792 * us up is to directly schedule the thread.
793 *
794 * Setting TDF_SINTR will cause new signals to directly schedule us.
795 *
ae8e83e6 796 * This routine must be called while in a critical section.
a22c590e
MD
797 */
798int
799lwkt_sleep(const char *wmesg, int flags)
800{
801 thread_t td = curthread;
802 int sig;
803
804 if ((flags & PCATCH) == 0 || td->td_lwp == NULL) {
805 td->td_flags |= TDF_BLOCKED;
806 td->td_wmesg = wmesg;
807 lwkt_deschedule_self(td);
808 lwkt_switch();
809 td->td_wmesg = NULL;
810 td->td_flags &= ~TDF_BLOCKED;
811 return(0);
812 }
813 if ((sig = CURSIG(td->td_lwp)) != 0) {
814 if (SIGISMEMBER(td->td_proc->p_sigacts->ps_sigintr, sig))
815 return(EINTR);
816 else
817 return(ERESTART);
818
819 }
820 td->td_flags |= TDF_BLOCKED | TDF_SINTR;
821 td->td_wmesg = wmesg;
822 lwkt_deschedule_self(td);
823 lwkt_switch();
824 td->td_flags &= ~(TDF_BLOCKED | TDF_SINTR);
825 td->td_wmesg = NULL;
826 return(0);
827}
828
829/*
344ad853 830 * Implement the timeout for tsleep.
fc17ad60 831 *
9a379a4a 832 * We set LWP_BREAKTSLEEP to indicate that an event has occured, but
344ad853
MD
833 * we only call setrunnable if the process is not stopped.
834 *
835 * This type of callout timeout is scheduled on the same cpu the process
836 * is sleeping on. Also, at the moment, the MP lock is held.
984263bc
MD
837 */
838static void
0cfcada1 839endtsleep(void *arg)
984263bc 840{
0cfcada1 841 thread_t td = arg;
9a379a4a 842 struct lwp *lp;
984263bc 843
37af14fe 844 crit_enter();
98c2b8ac 845 lwkt_gettoken(&proc_token);
344ad853
MD
846
847 /*
848 * cpu interlock. Thread flags are only manipulated on
849 * the cpu owning the thread. proc flags are only manipulated
850 * by the older of the MP lock. We have both.
851 */
ae8e83e6 852 if (td->td_flags & TDF_TSLEEP_DESCHEDULED) {
0cfcada1 853 td->td_flags |= TDF_TIMEOUT;
344ad853 854
9a379a4a
SS
855 if ((lp = td->td_lwp) != NULL) {
856 lp->lwp_flag |= LWP_BREAKTSLEEP;
857 if (lp->lwp_proc->p_stat != SSTOP)
858 setrunnable(lp);
0cfcada1 859 } else {
ae8e83e6 860 _tsleep_wakeup(td);
0cfcada1 861 }
984263bc 862 }
98c2b8ac 863 lwkt_reltoken(&proc_token);
37af14fe 864 crit_exit();
984263bc
MD
865}
866
984263bc 867/*
8fb8bca6 868 * Make all processes sleeping on the specified identifier runnable.
fc17ad60
MD
869 * count may be zero or one only.
870 *
871 * The domain encodes the sleep/wakeup domain AND the first cpu to check
872 * (which is always the current cpu). As we iterate across cpus
344ad853
MD
873 *
874 * This call may run without the MP lock held. We can only manipulate thread
875 * state on the cpu owning the thread. We CANNOT manipulate process state
876 * at all.
5decebc7
MD
877 *
878 * _wakeup() can be passed to an IPI so we can't use (const volatile
879 * void *ident).
8fb8bca6
EN
880 */
881static void
fc17ad60 882_wakeup(void *ident, int domain)
8fb8bca6 883{
fc17ad60 884 struct tslpque *qp;
0cfcada1
MD
885 struct thread *td;
886 struct thread *ntd;
fc17ad60 887 globaldata_t gd;
fc17ad60
MD
888#ifdef SMP
889 cpumask_t mask;
fc17ad60
MD
890#endif
891 int id;
984263bc 892
37af14fe 893 crit_enter();
8aa3430c 894 logtsleep2(wakeup_beg, ident);
fc17ad60
MD
895 gd = mycpu;
896 id = LOOKUP(ident);
897 qp = &gd->gd_tsleep_hash[id];
984263bc 898restart:
0cfcada1 899 for (td = TAILQ_FIRST(qp); td != NULL; td = ntd) {
ae8e83e6 900 ntd = TAILQ_NEXT(td, td_sleepq);
fc17ad60
MD
901 if (td->td_wchan == ident &&
902 td->td_wdomain == (domain & PDOMAIN_MASK)
903 ) {
ae8e83e6
MD
904 KKASSERT(td->td_gd == gd);
905 _tsleep_remove(td);
906 if (td->td_flags & TDF_TSLEEP_DESCHEDULED) {
907 td->td_flags &= ~TDF_TSLEEP_DESCHEDULED;
908 lwkt_schedule(td);
909 if (domain & PWAKEUP_ONE)
910 goto done;
fc17ad60 911 }
0cfcada1 912 goto restart;
984263bc
MD
913 }
914 }
fc17ad60
MD
915
916#ifdef SMP
917 /*
918 * We finished checking the current cpu but there still may be
919 * more work to do. Either wakeup_one was requested and no matching
920 * thread was found, or a normal wakeup was requested and we have
921 * to continue checking cpus.
922 *
fc17ad60
MD
923 * It should be noted that this scheme is actually less expensive then
924 * the old scheme when waking up multiple threads, since we send
925 * only one IPI message per target candidate which may then schedule
926 * multiple threads. Before we could have wound up sending an IPI
927 * message for each thread on the target cpu (!= current cpu) that
928 * needed to be woken up.
929 *
930 * NOTE: Wakeups occuring on remote cpus are asynchronous. This
931 * should be ok since we are passing idents in the IPI rather then
932 * thread pointers.
933 */
1f4f6e0b
MD
934 if ((domain & PWAKEUP_MYCPU) == 0 &&
935 (mask = slpque_cpumasks[id] & gd->gd_other_cpus) != 0) {
936 lwkt_send_ipiq2_mask(mask, _wakeup, ident,
937 domain | PWAKEUP_MYCPU);
fc17ad60
MD
938 }
939#endif
940done:
8aa3430c 941 logtsleep1(wakeup_end);
37af14fe 942 crit_exit();
984263bc
MD
943}
944
b336a9b1
MD
945/*
946 * Wakeup all threads tsleep()ing on the specified ident, on all cpus
947 */
984263bc 948void
5decebc7 949wakeup(const volatile void *ident)
984263bc 950{
5decebc7 951 _wakeup(__DEALL(ident), PWAKEUP_ENCODE(0, mycpu->gd_cpuid));
0cfcada1 952}
984263bc 953
b336a9b1
MD
954/*
955 * Wakeup one thread tsleep()ing on the specified ident, on any cpu.
956 */
0cfcada1 957void
5decebc7 958wakeup_one(const volatile void *ident)
0cfcada1 959{
fc17ad60 960 /* XXX potentially round-robin the first responding cpu */
5decebc7 961 _wakeup(__DEALL(ident), PWAKEUP_ENCODE(0, mycpu->gd_cpuid) | PWAKEUP_ONE);
da5fb9ef
MD
962}
963
b336a9b1
MD
964/*
965 * Wakeup threads tsleep()ing on the specified ident on the current cpu
966 * only.
967 */
968void
5decebc7 969wakeup_mycpu(const volatile void *ident)
b336a9b1 970{
5decebc7 971 _wakeup(__DEALL(ident), PWAKEUP_MYCPU);
b336a9b1
MD
972}
973
974/*
975 * Wakeup one thread tsleep()ing on the specified ident on the current cpu
976 * only.
977 */
978void
5decebc7 979wakeup_mycpu_one(const volatile void *ident)
b336a9b1
MD
980{
981 /* XXX potentially round-robin the first responding cpu */
5decebc7 982 _wakeup(__DEALL(ident), PWAKEUP_MYCPU|PWAKEUP_ONE);
b336a9b1
MD
983}
984
985/*
986 * Wakeup all thread tsleep()ing on the specified ident on the specified cpu
987 * only.
988 */
989void
5decebc7 990wakeup_oncpu(globaldata_t gd, const volatile void *ident)
b336a9b1 991{
1699d292 992#ifdef SMP
b336a9b1 993 if (gd == mycpu) {
5decebc7 994 _wakeup(__DEALL(ident), PWAKEUP_MYCPU);
b336a9b1 995 } else {
5decebc7 996 lwkt_send_ipiq2(gd, _wakeup, __DEALL(ident), PWAKEUP_MYCPU);
b336a9b1 997 }
1699d292 998#else
8e44b950 999 _wakeup(__DEALL(ident), PWAKEUP_MYCPU);
1699d292 1000#endif
b336a9b1
MD
1001}
1002
1003/*
1004 * Wakeup one thread tsleep()ing on the specified ident on the specified cpu
1005 * only.
1006 */
1007void
5decebc7 1008wakeup_oncpu_one(globaldata_t gd, const volatile void *ident)
b336a9b1 1009{
1699d292 1010#ifdef SMP
b336a9b1 1011 if (gd == mycpu) {
5decebc7 1012 _wakeup(__DEALL(ident), PWAKEUP_MYCPU | PWAKEUP_ONE);
b336a9b1 1013 } else {
5decebc7
MD
1014 lwkt_send_ipiq2(gd, _wakeup, __DEALL(ident),
1015 PWAKEUP_MYCPU | PWAKEUP_ONE);
b336a9b1 1016 }
1699d292 1017#else
8e44b950 1018 _wakeup(__DEALL(ident), PWAKEUP_MYCPU | PWAKEUP_ONE);
1699d292 1019#endif
b336a9b1
MD
1020}
1021
1022/*
1023 * Wakeup all threads waiting on the specified ident that slept using
1024 * the specified domain, on all cpus.
1025 */
da5fb9ef 1026void
5decebc7 1027wakeup_domain(const volatile void *ident, int domain)
da5fb9ef 1028{
5decebc7 1029 _wakeup(__DEALL(ident), PWAKEUP_ENCODE(domain, mycpu->gd_cpuid));
da5fb9ef
MD
1030}
1031
b336a9b1
MD
1032/*
1033 * Wakeup one thread waiting on the specified ident that slept using
1034 * the specified domain, on any cpu.
1035 */
da5fb9ef 1036void
5decebc7 1037wakeup_domain_one(const volatile void *ident, int domain)
da5fb9ef 1038{
fc17ad60 1039 /* XXX potentially round-robin the first responding cpu */
5decebc7
MD
1040 _wakeup(__DEALL(ident),
1041 PWAKEUP_ENCODE(domain, mycpu->gd_cpuid) | PWAKEUP_ONE);
984263bc
MD
1042}
1043
1044/*
344ad853
MD
1045 * setrunnable()
1046 *
98c2b8ac 1047 * Make a process runnable. The proc_token must be held on call. This only
344ad853 1048 * has an effect if we are in SSLEEP. We only break out of the
9a379a4a 1049 * tsleep if LWP_BREAKTSLEEP is set, otherwise we just fix-up the state.
37af14fe 1050 *
74c9628e
MD
1051 * NOTE: With proc_token held we can only safely manipulate the process
1052 * structure and the lp's lwp_stat.
984263bc
MD
1053 */
1054void
9a379a4a 1055setrunnable(struct lwp *lp)
984263bc 1056{
98c2b8ac 1057 ASSERT_LWKT_TOKEN_HELD(&proc_token);
344ad853 1058 crit_enter();
2daf83b0
SS
1059 if (lp->lwp_stat == LSSTOP)
1060 lp->lwp_stat = LSSLEEP;
1061 if (lp->lwp_stat == LSSLEEP && (lp->lwp_flag & LWP_BREAKTSLEEP))
ae8e83e6 1062 _tsleep_wakeup(lp->lwp_thread);
344ad853 1063 crit_exit();
984263bc
MD
1064}
1065
1066/*
164b8401
SS
1067 * The process is stopped due to some condition, usually because p_stat is
1068 * set to SSTOP, but also possibly due to being traced.
fc17ad60 1069 *
164b8401 1070 * NOTE! If the caller sets SSTOP, the caller must also clear P_WAITED
344ad853
MD
1071 * because the parent may check the child's status before the child actually
1072 * gets to this routine.
1073 *
9a379a4a 1074 * This routine is called with the current lwp only, typically just
344ad853
MD
1075 * before returning to userland.
1076 *
9a379a4a 1077 * Setting LWP_BREAKTSLEEP before entering the tsleep will cause a passive
344ad853 1078 * SIGCONT to break out of the tsleep.
984263bc
MD
1079 */
1080void
9a379a4a 1081tstop(void)
984263bc 1082{
9a379a4a 1083 struct lwp *lp = curthread->td_lwp;
7278a846 1084 struct proc *p = lp->lwp_proc;
9a379a4a 1085
7278a846 1086 crit_enter();
f33e8653
SS
1087 /*
1088 * If LWP_WSTOP is set, we were sleeping
1089 * while our process was stopped. At this point
1090 * we were already counted as stopped.
1091 */
1092 if ((lp->lwp_flag & LWP_WSTOP) == 0) {
1093 /*
1094 * If we're the last thread to stop, signal
1095 * our parent.
1096 */
1097 p->p_nstopped++;
1098 lp->lwp_flag |= LWP_WSTOP;
ea59a697 1099 wakeup(&p->p_nstopped);
f33e8653
SS
1100 if (p->p_nstopped == p->p_nthreads) {
1101 p->p_flag &= ~P_WAITED;
1102 wakeup(p->p_pptr);
1103 if ((p->p_pptr->p_sigacts->ps_flag & PS_NOCLDSTOP) == 0)
1104 ksignal(p->p_pptr, SIGCHLD);
1105 }
1106 }
ea59a697
SS
1107 while (p->p_stat == SSTOP) {
1108 lp->lwp_flag |= LWP_BREAKTSLEEP;
1109 lp->lwp_stat = LSSTOP;
1110 tsleep(p, 0, "stop", 0);
1111 }
7278a846 1112 p->p_nstopped--;
a5ff9d37 1113 lp->lwp_flag &= ~LWP_WSTOP;
7278a846 1114 crit_exit();
26a0694b
MD
1115}
1116
1117/*
984263bc
MD
1118 * Compute a tenex style load average of a quantity on
1119 * 1, 5 and 15 minute intervals.
1120 */
c7e98b2f 1121static int loadav_count_runnable(struct lwp *p, void *data);
8fa76237 1122
984263bc
MD
1123static void
1124loadav(void *arg)
1125{
984263bc 1126 struct loadavg *avg;
8fa76237 1127 int i, nrun;
984263bc 1128
984263bc 1129 nrun = 0;
c7e98b2f 1130 alllwp_scan(loadav_count_runnable, &nrun);
8fa76237
MD
1131 avg = &averunnable;
1132 for (i = 0; i < 3; i++) {
984263bc
MD
1133 avg->ldavg[i] = (cexp[i] * avg->ldavg[i] +
1134 nrun * FSCALE * (FSCALE - cexp[i])) >> FSHIFT;
8fa76237 1135 }
984263bc
MD
1136
1137 /*
1138 * Schedule the next update to occur after 5 seconds, but add a
1139 * random variation to avoid synchronisation with processes that
1140 * run at regular intervals.
1141 */
cddfb7bb 1142 callout_reset(&loadav_callout, hz * 4 + (int)(krandom() % (hz * 2 + 1)),
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1143 loadav, NULL);
1144}
1145
1146static int
c7e98b2f 1147loadav_count_runnable(struct lwp *lp, void *data)
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1148{
1149 int *nrunp = data;
1150 thread_t td;
1151
164b8401
SS
1152 switch (lp->lwp_stat) {
1153 case LSRUN:
08f2f1bb 1154 if ((td = lp->lwp_thread) == NULL)
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1155 break;
1156 if (td->td_flags & TDF_BLOCKED)
1157 break;
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1158 ++*nrunp;
1159 break;
1160 default:
1161 break;
1162 }
1163 return(0);
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1164}
1165
1166/* ARGSUSED */
1167static void
6656cd91 1168sched_setup(void *dummy)
984263bc 1169{
984263bc 1170 callout_init(&loadav_callout);
35f9d051 1171 callout_init(&schedcpu_callout);
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1172
1173 /* Kick off timeout driven events by calling first time. */
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1174 schedcpu(NULL);
1175 loadav(NULL);
1176}
1177