Formalize the object sleep/wakeup code when waiting on a dead VM object and
[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 $
a22c590e 40 * $DragonFly: src/sys/kern/kern_synch.c,v 1.85 2007/05/24 20:51:16 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>
b1b4e5a6 50#include <sys/signal2.h>
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51#include <sys/resourcevar.h>
52#include <sys/vmmeter.h>
53#include <sys/sysctl.h>
344ad853 54#include <sys/lock.h>
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55#ifdef KTRACE
56#include <sys/uio.h>
57#include <sys/ktrace.h>
58#endif
f1d1c3fa 59#include <sys/xwait.h>
9afb0ffd 60#include <sys/ktr.h>
984263bc 61
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62#include <sys/thread2.h>
63#include <sys/spinlock2.h>
64
984263bc 65#include <machine/cpu.h>
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66#include <machine/smp.h>
67
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68TAILQ_HEAD(tslpque, thread);
69
402ed7e1 70static void sched_setup (void *dummy);
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71SYSINIT(sched_setup, SI_SUB_KICK_SCHEDULER, SI_ORDER_FIRST, sched_setup, NULL)
72
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73int hogticks;
74int lbolt;
344ad853 75int lbolt_syncer;
984263bc 76int sched_quantum; /* Roundrobin scheduling quantum in ticks. */
17a9f566 77int ncpus;
90100055 78int ncpus2, ncpus2_shift, ncpus2_mask;
b45759e1 79int ncpus_fit, ncpus_fit_mask;
e43a034f 80int safepri;
dbcd0c9b 81int tsleep_now_works;
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82
83static struct callout loadav_callout;
35f9d051 84static struct callout schedcpu_callout;
fc17ad60 85MALLOC_DEFINE(M_TSLEEP, "tslpque", "tsleep queues");
984263bc 86
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87#if !defined(KTR_TSLEEP)
88#define KTR_TSLEEP KTR_ALL
89#endif
90KTR_INFO_MASTER(tsleep);
91KTR_INFO(KTR_TSLEEP, tsleep, tsleep_beg, 0, "tsleep enter", 0);
92KTR_INFO(KTR_TSLEEP, tsleep, tsleep_end, 0, "tsleep exit", 0);
93KTR_INFO(KTR_TSLEEP, tsleep, wakeup_beg, 0, "wakeup enter", 0);
94KTR_INFO(KTR_TSLEEP, tsleep, wakeup_end, 0, "wakeup exit", 0);
95#define logtsleep(name) KTR_LOG(tsleep_ ## name)
96
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97struct loadavg averunnable =
98 { {0, 0, 0}, FSCALE }; /* load average, of runnable procs */
99/*
100 * Constants for averages over 1, 5, and 15 minutes
101 * when sampling at 5 second intervals.
102 */
103static fixpt_t cexp[3] = {
104 0.9200444146293232 * FSCALE, /* exp(-1/12) */
105 0.9834714538216174 * FSCALE, /* exp(-1/60) */
106 0.9944598480048967 * FSCALE, /* exp(-1/180) */
107};
108
402ed7e1 109static void endtsleep (void *);
344ad853 110static void unsleep_and_wakeup_thread(struct thread *td);
402ed7e1 111static void loadav (void *arg);
402ed7e1 112static void schedcpu (void *arg);
984263bc 113
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114/*
115 * Adjust the scheduler quantum. The quantum is specified in microseconds.
116 * Note that 'tick' is in microseconds per tick.
117 */
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118static int
119sysctl_kern_quantum(SYSCTL_HANDLER_ARGS)
120{
121 int error, new_val;
122
123 new_val = sched_quantum * tick;
124 error = sysctl_handle_int(oidp, &new_val, 0, req);
125 if (error != 0 || req->newptr == NULL)
126 return (error);
127 if (new_val < tick)
128 return (EINVAL);
129 sched_quantum = new_val / tick;
130 hogticks = 2 * sched_quantum;
131 return (0);
132}
133
134SYSCTL_PROC(_kern, OID_AUTO, quantum, CTLTYPE_INT|CTLFLAG_RW,
135 0, sizeof sched_quantum, sysctl_kern_quantum, "I", "");
136
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137/*
138 * If `ccpu' is not equal to `exp(-1/20)' and you still want to use the
139 * faster/more-accurate formula, you'll have to estimate CCPU_SHIFT below
140 * and possibly adjust FSHIFT in "param.h" so that (FSHIFT >= CCPU_SHIFT).
141 *
142 * To estimate CCPU_SHIFT for exp(-1/20), the following formula was used:
dcc99b62 143 * 1 - exp(-1/20) ~= 0.0487 ~= 0.0488 == 1 (fixed pt, *11* bits).
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144 *
145 * If you don't want to bother with the faster/more-accurate formula, you
146 * can set CCPU_SHIFT to (FSHIFT + 1) which will use a slower/less-accurate
147 * (more general) method of calculating the %age of CPU used by a process.
dcc99b62 148 *
08f2f1bb 149 * decay 95% of `lwp_pctcpu' in 60 seconds; see CCPU_SHIFT before changing
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150 */
151#define CCPU_SHIFT 11
152
153static fixpt_t ccpu = 0.95122942450071400909 * FSCALE; /* exp(-1/20) */
154SYSCTL_INT(_kern, OID_AUTO, ccpu, CTLFLAG_RD, &ccpu, 0, "");
155
156/*
157 * kernel uses `FSCALE', userland (SHOULD) use kern.fscale
984263bc 158 */
460426e6 159int fscale __unused = FSCALE; /* exported to systat */
dcc99b62 160SYSCTL_INT(_kern, OID_AUTO, fscale, CTLFLAG_RD, 0, FSCALE, "");
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161
162/*
0a3f9b47 163 * Recompute process priorities, once a second.
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164 *
165 * Since the userland schedulers are typically event oriented, if the
166 * estcpu calculation at wakeup() time is not sufficient to make a
167 * process runnable relative to other processes in the system we have
168 * a 1-second recalc to help out.
169 *
170 * This code also allows us to store sysclock_t data in the process structure
171 * without fear of an overrun, since sysclock_t are guarenteed to hold
172 * several seconds worth of count.
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173 *
174 * WARNING! callouts can preempt normal threads. However, they will not
175 * preempt a thread holding a spinlock so we *can* safely use spinlocks.
984263bc 176 */
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177static int schedcpu_stats(struct proc *p, void *data __unused);
178static int schedcpu_resource(struct proc *p, void *data __unused);
179
984263bc 180static void
26a0694b 181schedcpu(void *arg)
984263bc 182{
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183 allproc_scan(schedcpu_stats, NULL);
184 allproc_scan(schedcpu_resource, NULL);
185 wakeup((caddr_t)&lbolt);
186 wakeup((caddr_t)&lbolt_syncer);
187 callout_reset(&schedcpu_callout, hz, schedcpu, NULL);
188}
189
190/*
191 * General process statistics once a second
192 */
193static int
194schedcpu_stats(struct proc *p, void *data __unused)
195{
08f2f1bb
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196 struct lwp *lp;
197
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198 crit_enter();
199 p->p_swtime++;
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200 FOREACH_LWP_IN_PROC(lp, p) {
201 if (lp->lwp_stat == LSSLEEP)
202 lp->lwp_slptime++;
4b5f931b 203
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204 /*
205 * Only recalculate processes that are active or have slept
206 * less then 2 seconds. The schedulers understand this.
207 */
208 if (lp->lwp_slptime <= 1) {
209 p->p_usched->recalculate(lp);
210 } else {
211 lp->lwp_pctcpu = (lp->lwp_pctcpu * ccpu) >> FSHIFT;
212 }
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213 }
214 crit_exit();
215 return(0);
216}
a46fac56 217
8fa76237 218/*
84204577 219 * Resource checks. XXX break out since ksignal/killproc can block,
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220 * limiting us to one process killed per second. There is probably
221 * a better way.
222 */
223static int
224schedcpu_resource(struct proc *p, void *data __unused)
225{
226 u_int64_t ttime;
08f2f1bb 227 struct lwp *lp;
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228
229 crit_enter();
230 if (p->p_stat == SIDL ||
416d05d7 231 p->p_stat == SZOMB ||
c7e98b2f 232 p->p_limit == NULL
8fa76237 233 ) {
e43a034f 234 crit_exit();
8fa76237 235 return(0);
984263bc 236 }
344ad853 237
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238 ttime = 0;
239 FOREACH_LWP_IN_PROC(lp, p) {
240 ttime += lp->lwp_thread->td_sticks;
241 ttime += lp->lwp_thread->td_uticks;
242 }
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243
244 switch(plimit_testcpulimit(p->p_limit, ttime)) {
245 case PLIMIT_TESTCPU_KILL:
246 killproc(p, "exceeded maximum CPU limit");
247 break;
248 case PLIMIT_TESTCPU_XCPU:
249 if ((p->p_flag & P_XCPU) == 0) {
250 p->p_flag |= P_XCPU;
84204577 251 ksignal(p, SIGXCPU);
344ad853 252 }
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253 break;
254 default:
c0b8a06d 255 break;
344ad853 256 }
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257 crit_exit();
258 return(0);
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259}
260
261/*
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262 * This is only used by ps. Generate a cpu percentage use over
263 * a period of one second.
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264 *
265 * MPSAFE
984263bc 266 */
dcc99b62 267void
553ea3c8 268updatepcpu(struct lwp *lp, int cpticks, int ttlticks)
984263bc 269{
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270 fixpt_t acc;
271 int remticks;
272
273 acc = (cpticks << FSHIFT) / ttlticks;
274 if (ttlticks >= ESTCPUFREQ) {
553ea3c8 275 lp->lwp_pctcpu = acc;
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276 } else {
277 remticks = ESTCPUFREQ - ttlticks;
553ea3c8 278 lp->lwp_pctcpu = (acc * ttlticks + lp->lwp_pctcpu * remticks) /
dcc99b62 279 ESTCPUFREQ;
a46fac56 280 }
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281}
282
283/*
284 * We're only looking at 7 bits of the address; everything is
285 * aligned to 4, lots of things are aligned to greater powers
286 * of 2. Shift right by 8, i.e. drop the bottom 256 worth.
287 */
288#define TABLESIZE 128
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289#define LOOKUP(x) (((intptr_t)(x) >> 8) & (TABLESIZE - 1))
290
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291static cpumask_t slpque_cpumasks[TABLESIZE];
292
984263bc 293/*
a46fac56 294 * General scheduler initialization. We force a reschedule 25 times
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295 * a second by default. Note that cpu0 is initialized in early boot and
296 * cannot make any high level calls.
297 *
298 * Each cpu has its own sleep queue.
984263bc 299 */
984263bc 300void
fc17ad60 301sleep_gdinit(globaldata_t gd)
984263bc 302{
fc17ad60 303 static struct tslpque slpque_cpu0[TABLESIZE];
9c1fad94 304 int i;
984263bc 305
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306 if (gd->gd_cpuid == 0) {
307 sched_quantum = (hz + 24) / 25;
308 hogticks = 2 * sched_quantum;
309
310 gd->gd_tsleep_hash = slpque_cpu0;
311 } else {
77652cad 312 gd->gd_tsleep_hash = kmalloc(sizeof(slpque_cpu0),
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313 M_TSLEEP, M_WAITOK | M_ZERO);
314 }
315 for (i = 0; i < TABLESIZE; ++i)
316 TAILQ_INIT(&gd->gd_tsleep_hash[i]);
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317}
318
319/*
320 * General sleep call. Suspends the current process until a wakeup is
321 * performed on the specified identifier. The process will then be made
322 * runnable with the specified priority. Sleeps at most timo/hz seconds
377d4740 323 * (0 means no timeout). If flags includes PCATCH flag, signals are checked
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324 * before and after sleeping, else signals are not checked. Returns 0 if
325 * awakened, EWOULDBLOCK if the timeout expires. If PCATCH is set and a
326 * signal needs to be delivered, ERESTART is returned if the current system
327 * call should be restarted if possible, and EINTR is returned if the system
328 * call should be interrupted by the signal (return EINTR).
26a0694b 329 *
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330 * Note that if we are a process, we release_curproc() before messing with
331 * the LWKT scheduler.
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332 *
333 * During autoconfiguration or after a panic, a sleep will simply
334 * lower the priority briefly to allow interrupts, then return.
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335 */
336int
6656cd91 337tsleep(void *ident, int flags, const char *wmesg, int timo)
984263bc 338{
dadab5e9 339 struct thread *td = curthread;
08f2f1bb 340 struct lwp *lp = td->td_lwp;
0cfcada1 341 struct proc *p = td->td_proc; /* may be NULL */
fc17ad60 342 globaldata_t gd;
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343 int sig;
344 int catch;
345 int id;
346 int error;
e43a034f 347 int oldpri;
076fecef 348 struct callout thandle;
984263bc 349
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350 /*
351 * NOTE: removed KTRPOINT, it could cause races due to blocking
352 * even in stable. Just scrap it for now.
353 */
dbcd0c9b 354 if (tsleep_now_works == 0 || panicstr) {
984263bc 355 /*
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356 * After a panic, or before we actually have an operational
357 * softclock, just give interrupts a chance, then just return;
358 *
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359 * don't run any other procs or panic below,
360 * in case this is the idle process and already asleep.
361 */
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362 splz();
363 oldpri = td->td_pri & TDPRI_MASK;
364 lwkt_setpri_self(safepri);
365 lwkt_switch();
366 lwkt_setpri_self(oldpri);
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367 return (0);
368 }
9afb0ffd 369 logtsleep(tsleep_beg);
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370 gd = td->td_gd;
371 KKASSERT(td != &gd->gd_idlethread); /* you must be kidding! */
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372
373 /*
374 * NOTE: all of this occurs on the current cpu, including any
375 * callout-based wakeups, so a critical section is a sufficient
376 * interlock.
377 *
378 * The entire sequence through to where we actually sleep must
379 * run without breaking the critical section.
380 */
381 id = LOOKUP(ident);
382 catch = flags & PCATCH;
383 error = 0;
384 sig = 0;
385
37af14fe 386 crit_enter_quick(td);
344ad853 387
0cfcada1 388 KASSERT(ident != NULL, ("tsleep: no ident"));
7278a846
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389 KASSERT(lp == NULL ||
390 lp->lwp_stat == LSRUN || /* Obvious */
391 lp->lwp_stat == LSSTOP, /* Set in tstop */
392 ("tsleep %p %s %d",
393 ident, wmesg, lp->lwp_stat));
0cfcada1 394
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395 /*
396 * Setup for the current process (if this is a process).
397 */
08f2f1bb 398 if (lp) {
344ad853
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399 if (catch) {
400 /*
401 * Early termination if PCATCH was set and a
402 * signal is pending, interlocked with the
403 * critical section.
404 *
405 * Early termination only occurs when tsleep() is
164b8401 406 * entered while in a normal LSRUN state.
344ad853 407 */
08f2f1bb 408 if ((sig = CURSIG(lp)) != 0)
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409 goto resume;
410
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411 /*
412 * Early termination if PCATCH was set and a
413 * mailbox signal was possibly delivered prior to
414 * the system call even being made, in order to
415 * allow the user to interlock without having to
416 * make additional system calls.
417 */
418 if (p->p_flag & P_MAILBOX)
419 goto resume;
420
344ad853 421 /*
84204577 422 * Causes ksignal to wake us up when.
344ad853 423 */
9a379a4a 424 lp->lwp_flag |= LWP_SINTR;
344ad853
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425 }
426
427 /*
428 * Make sure the current process has been untangled from
429 * the userland scheduler and initialize slptime to start
430 * counting.
431 */
0a3f9b47
MD
432 if (flags & PNORESCHED)
433 td->td_flags |= TDF_NORESCHED;
08f2f1bb
SS
434 p->p_usched->release_curproc(lp);
435 lp->lwp_slptime = 0;
0a3f9b47 436 }
fc17ad60
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437
438 /*
344ad853 439 * Move our thread to the correct queue and setup our wchan, etc.
fc17ad60 440 */
37af14fe 441 lwkt_deschedule_self(td);
344ad853 442 td->td_flags |= TDF_TSLEEPQ;
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443 TAILQ_INSERT_TAIL(&gd->gd_tsleep_hash[id], td, td_threadq);
444 atomic_set_int(&slpque_cpumasks[id], gd->gd_cpumask);
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445
446 td->td_wchan = ident;
447 td->td_wmesg = wmesg;
448 td->td_wdomain = flags & PDOMAIN_MASK;
449
450 /*
451 * Setup the timeout, if any
452 */
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453 if (timo) {
454 callout_init(&thandle);
455 callout_reset(&thandle, timo, endtsleep, td);
456 }
344ad853 457
984263bc 458 /*
344ad853 459 * Beddy bye bye.
984263bc 460 */
08f2f1bb 461 if (lp) {
26a0694b 462 /*
52eedfb5 463 * Ok, we are sleeping. Place us in the SSLEEP state.
26a0694b 464 */
9388413d 465 KKASSERT((lp->lwp_flag & LWP_ONRUNQ) == 0);
7278a846
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466 /*
467 * tstop() sets LSSTOP, so don't fiddle with that.
468 */
469 if (lp->lwp_stat != LSSTOP)
470 lp->lwp_stat = LSSLEEP;
08f2f1bb 471 lp->lwp_ru.ru_nvcsw++;
344ad853 472 lwkt_switch();
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473
474 /*
164b8401 475 * And when we are woken up, put us back in LSRUN. If we
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476 * slept for over a second, recalculate our estcpu.
477 */
164b8401 478 lp->lwp_stat = LSRUN;
08f2f1bb
SS
479 if (lp->lwp_slptime)
480 p->p_usched->recalculate(lp);
481 lp->lwp_slptime = 0;
0cfcada1
MD
482 } else {
483 lwkt_switch();
484 }
344ad853 485
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486 /*
487 * Make sure we haven't switched cpus while we were asleep. It's
344ad853 488 * not supposed to happen. Cleanup our temporary flags.
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489 */
490 KKASSERT(gd == td->td_gd);
0a3f9b47 491 td->td_flags &= ~TDF_NORESCHED;
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492
493 /*
494 * Cleanup the timeout.
495 */
496 if (timo) {
497 if (td->td_flags & TDF_TIMEOUT) {
498 td->td_flags &= ~TDF_TIMEOUT;
a40da8f0 499 error = EWOULDBLOCK;
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500 } else {
501 callout_stop(&thandle);
502 }
0cfcada1 503 }
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504
505 /*
506 * Since td_threadq is used both for our run queue AND for the
507 * tsleep hash queue, we can't still be on it at this point because
508 * we've gotten cpu back.
509 */
afbfc034 510 KASSERT((td->td_flags & TDF_TSLEEPQ) == 0, ("tsleep: impossible thread flags %08x", td->td_flags));
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511 td->td_wchan = NULL;
512 td->td_wmesg = NULL;
513 td->td_wdomain = 0;
514
515 /*
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516 * Figure out the correct error return. If interrupted by a
517 * signal we want to return EINTR or ERESTART.
518 *
519 * If P_MAILBOX is set no automatic system call restart occurs
520 * and we return EINTR. P_MAILBOX is meant to be used as an
521 * interlock, the user must poll it prior to any system call
522 * that it wishes to interlock a mailbox signal against since
523 * the flag is cleared on *any* system call that sleeps.
344ad853
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524 */
525resume:
0cfcada1 526 if (p) {
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527 if (catch && error == 0) {
528 if ((p->p_flag & P_MAILBOX) && sig == 0) {
344ad853 529 error = EINTR;
08f2f1bb 530 } else if (sig != 0 || (sig = CURSIG(lp))) {
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MD
531 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig))
532 error = EINTR;
533 else
534 error = ERESTART;
535 }
984263bc 536 }
9a379a4a
SS
537 lp->lwp_flag &= ~(LWP_BREAKTSLEEP | LWP_SINTR);
538 p->p_flag &= ~P_MAILBOX;
984263bc 539 }
9afb0ffd 540 logtsleep(tsleep_end);
344ad853
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541 crit_exit_quick(td);
542 return (error);
984263bc
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543}
544
16523a43
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545/*
546 * This is a dandy function that allows us to interlock tsleep/wakeup
547 * operations with unspecified upper level locks, such as lockmgr locks,
548 * simply by holding a critical section. The sequence is:
549 *
550 * (enter critical section)
551 * (acquire upper level lock)
552 * tsleep_interlock(blah)
553 * (release upper level lock)
554 * tsleep(blah, ...)
555 * (exit critical section)
556 *
557 * Basically this function sets our cpumask for the ident which informs
558 * other cpus that our cpu 'might' be waiting (or about to wait on) the
559 * hash index related to the ident. The critical section prevents another
560 * cpu's wakeup() from being processed on our cpu until we are actually
561 * able to enter the tsleep(). Thus, no race occurs between our attempt
562 * to release a resource and sleep, and another cpu's attempt to acquire
563 * a resource and call wakeup.
564 *
565 * There isn't much of a point to this function unless you call it while
566 * holding a critical section.
567 */
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568static __inline void
569_tsleep_interlock(globaldata_t gd, void *ident)
570{
571 int id = LOOKUP(ident);
572
573 atomic_set_int(&slpque_cpumasks[id], gd->gd_cpumask);
574}
575
16523a43
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576void
577tsleep_interlock(void *ident)
578{
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579 _tsleep_interlock(mycpu, ident);
580}
581
582/*
583 * Interlocked spinlock sleep. An exclusively held spinlock must
584 * be passed to msleep(). The function will atomically release the
585 * spinlock and tsleep on the ident, then reacquire the spinlock and
586 * return.
587 *
588 * This routine is fairly important along the critical path, so optimize it
589 * heavily.
590 */
591int
592msleep(void *ident, struct spinlock *spin, int flags,
593 const char *wmesg, int timo)
594{
595 globaldata_t gd = mycpu;
596 int error;
16523a43 597
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598 crit_enter_gd(gd);
599 _tsleep_interlock(gd, ident);
600 spin_unlock_wr_quick(gd, spin);
601 error = tsleep(ident, flags, wmesg, timo);
602 spin_lock_wr_quick(gd, spin);
603 crit_exit_gd(gd);
604
605 return (error);
16523a43
MD
606}
607
a22c590e
MD
608/*
609 * Directly block on the LWKT thread by descheduling it. This
610 * is much faster then tsleep(), but the only legal way to wake
611 * us up is to directly schedule the thread.
612 *
613 * Setting TDF_SINTR will cause new signals to directly schedule us.
614 *
615 * This routine is typically called while in a critical section.
616 */
617int
618lwkt_sleep(const char *wmesg, int flags)
619{
620 thread_t td = curthread;
621 int sig;
622
623 if ((flags & PCATCH) == 0 || td->td_lwp == NULL) {
624 td->td_flags |= TDF_BLOCKED;
625 td->td_wmesg = wmesg;
626 lwkt_deschedule_self(td);
627 lwkt_switch();
628 td->td_wmesg = NULL;
629 td->td_flags &= ~TDF_BLOCKED;
630 return(0);
631 }
632 if ((sig = CURSIG(td->td_lwp)) != 0) {
633 if (SIGISMEMBER(td->td_proc->p_sigacts->ps_sigintr, sig))
634 return(EINTR);
635 else
636 return(ERESTART);
637
638 }
639 td->td_flags |= TDF_BLOCKED | TDF_SINTR;
640 td->td_wmesg = wmesg;
641 lwkt_deschedule_self(td);
642 lwkt_switch();
643 td->td_flags &= ~(TDF_BLOCKED | TDF_SINTR);
644 td->td_wmesg = NULL;
645 return(0);
646}
647
984263bc 648/*
344ad853 649 * Implement the timeout for tsleep.
fc17ad60 650 *
9a379a4a 651 * We set LWP_BREAKTSLEEP to indicate that an event has occured, but
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652 * we only call setrunnable if the process is not stopped.
653 *
654 * This type of callout timeout is scheduled on the same cpu the process
655 * is sleeping on. Also, at the moment, the MP lock is held.
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656 */
657static void
0cfcada1 658endtsleep(void *arg)
984263bc 659{
0cfcada1 660 thread_t td = arg;
9a379a4a 661 struct lwp *lp;
984263bc 662
344ad853 663 ASSERT_MP_LOCK_HELD(curthread);
37af14fe 664 crit_enter();
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665
666 /*
667 * cpu interlock. Thread flags are only manipulated on
668 * the cpu owning the thread. proc flags are only manipulated
669 * by the older of the MP lock. We have both.
670 */
671 if (td->td_flags & TDF_TSLEEPQ) {
0cfcada1 672 td->td_flags |= TDF_TIMEOUT;
344ad853 673
9a379a4a
SS
674 if ((lp = td->td_lwp) != NULL) {
675 lp->lwp_flag |= LWP_BREAKTSLEEP;
676 if (lp->lwp_proc->p_stat != SSTOP)
677 setrunnable(lp);
0cfcada1 678 } else {
344ad853 679 unsleep_and_wakeup_thread(td);
0cfcada1 680 }
984263bc 681 }
37af14fe 682 crit_exit();
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MD
683}
684
984263bc 685/*
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686 * Unsleep and wakeup a thread. This function runs without the MP lock
687 * which means that it can only manipulate thread state on the owning cpu,
688 * and cannot touch the process state at all.
984263bc 689 */
344ad853 690static
8fb8bca6 691void
344ad853 692unsleep_and_wakeup_thread(struct thread *td)
8fb8bca6 693{
344ad853 694 globaldata_t gd = mycpu;
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695 int id;
696
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697#ifdef SMP
698 if (td->td_gd != gd) {
699 lwkt_send_ipiq(td->td_gd, (ipifunc1_t)unsleep_and_wakeup_thread, td);
700 return;
701 }
702#endif
9c1fad94 703 crit_enter();
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704 if (td->td_flags & TDF_TSLEEPQ) {
705 td->td_flags &= ~TDF_TSLEEPQ;
706 id = LOOKUP(td->td_wchan);
707 TAILQ_REMOVE(&gd->gd_tsleep_hash[id], td, td_threadq);
708 if (TAILQ_FIRST(&gd->gd_tsleep_hash[id]) == NULL)
709 atomic_clear_int(&slpque_cpumasks[id], gd->gd_cpumask);
710 lwkt_schedule(td);
8fb8bca6 711 }
9c1fad94 712 crit_exit();
8fb8bca6 713}
8fb8bca6
EN
714
715/*
716 * Make all processes sleeping on the specified identifier runnable.
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717 * count may be zero or one only.
718 *
719 * The domain encodes the sleep/wakeup domain AND the first cpu to check
720 * (which is always the current cpu). As we iterate across cpus
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721 *
722 * This call may run without the MP lock held. We can only manipulate thread
723 * state on the cpu owning the thread. We CANNOT manipulate process state
724 * at all.
8fb8bca6
EN
725 */
726static void
fc17ad60 727_wakeup(void *ident, int domain)
984263bc 728{
fc17ad60 729 struct tslpque *qp;
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730 struct thread *td;
731 struct thread *ntd;
fc17ad60 732 globaldata_t gd;
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733#ifdef SMP
734 cpumask_t mask;
735 cpumask_t tmask;
736 int startcpu;
737 int nextcpu;
738#endif
739 int id;
984263bc 740
37af14fe 741 crit_enter();
9afb0ffd 742 logtsleep(wakeup_beg);
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743 gd = mycpu;
744 id = LOOKUP(ident);
745 qp = &gd->gd_tsleep_hash[id];
984263bc 746restart:
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MD
747 for (td = TAILQ_FIRST(qp); td != NULL; td = ntd) {
748 ntd = TAILQ_NEXT(td, td_threadq);
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749 if (td->td_wchan == ident &&
750 td->td_wdomain == (domain & PDOMAIN_MASK)
751 ) {
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752 KKASSERT(td->td_flags & TDF_TSLEEPQ);
753 td->td_flags &= ~TDF_TSLEEPQ;
0cfcada1 754 TAILQ_REMOVE(qp, td, td_threadq);
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MD
755 if (TAILQ_FIRST(qp) == NULL) {
756 atomic_clear_int(&slpque_cpumasks[id],
757 gd->gd_cpumask);
758 }
344ad853 759 lwkt_schedule(td);
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MD
760 if (domain & PWAKEUP_ONE)
761 goto done;
0cfcada1 762 goto restart;
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MD
763 }
764 }
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MD
765
766#ifdef SMP
767 /*
768 * We finished checking the current cpu but there still may be
769 * more work to do. Either wakeup_one was requested and no matching
770 * thread was found, or a normal wakeup was requested and we have
771 * to continue checking cpus.
772 *
773 * The cpu that started the wakeup sequence is encoded in the domain.
774 * We use this information to determine which cpus still need to be
775 * checked, locate a candidate cpu, and chain the wakeup
776 * asynchronously with an IPI message.
777 *
778 * It should be noted that this scheme is actually less expensive then
779 * the old scheme when waking up multiple threads, since we send
780 * only one IPI message per target candidate which may then schedule
781 * multiple threads. Before we could have wound up sending an IPI
782 * message for each thread on the target cpu (!= current cpu) that
783 * needed to be woken up.
784 *
785 * NOTE: Wakeups occuring on remote cpus are asynchronous. This
786 * should be ok since we are passing idents in the IPI rather then
787 * thread pointers.
788 */
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789 if ((domain & PWAKEUP_MYCPU) == 0 &&
790 (mask = slpque_cpumasks[id]) != 0
791 ) {
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792 /*
793 * Look for a cpu that might have work to do. Mask out cpus
794 * which have already been processed.
795 *
796 * 31xxxxxxxxxxxxxxxxxxxxxxxxxxxxx0
797 * ^ ^ ^
798 * start currentcpu start
799 * case2 case1
800 * * * *
801 * 11111111111111110000000000000111 case1
802 * 00000000111111110000000000000000 case2
803 *
804 * case1: We started at start_case1 and processed through
805 * to the current cpu. We have to check any bits
806 * after the current cpu, then check bits before
807 * the starting cpu.
808 *
809 * case2: We have already checked all the bits from
810 * start_case2 to the end, and from 0 to the current
811 * cpu. We just have the bits from the current cpu
812 * to start_case2 left to check.
813 */
814 startcpu = PWAKEUP_DECODE(domain);
815 if (gd->gd_cpuid >= startcpu) {
816 /*
817 * CASE1
818 */
819 tmask = mask & ~((gd->gd_cpumask << 1) - 1);
820 if (mask & tmask) {
821 nextcpu = bsfl(mask & tmask);
822 lwkt_send_ipiq2(globaldata_find(nextcpu),
823 _wakeup, ident, domain);
824 } else {
825 tmask = (1 << startcpu) - 1;
826 if (mask & tmask) {
827 nextcpu = bsfl(mask & tmask);
828 lwkt_send_ipiq2(
829 globaldata_find(nextcpu),
830 _wakeup, ident, domain);
831 }
832 }
833 } else {
834 /*
835 * CASE2
836 */
837 tmask = ~((gd->gd_cpumask << 1) - 1) &
838 ((1 << startcpu) - 1);
839 if (mask & tmask) {
840 nextcpu = bsfl(mask & tmask);
841 lwkt_send_ipiq2(globaldata_find(nextcpu),
842 _wakeup, ident, domain);
843 }
844 }
845 }
846#endif
847done:
9afb0ffd 848 logtsleep(wakeup_end);
37af14fe 849 crit_exit();
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MD
850}
851
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852/*
853 * Wakeup all threads tsleep()ing on the specified ident, on all cpus
854 */
984263bc 855void
0cfcada1 856wakeup(void *ident)
984263bc 857{
fc17ad60 858 _wakeup(ident, PWAKEUP_ENCODE(0, mycpu->gd_cpuid));
0cfcada1 859}
984263bc 860
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861/*
862 * Wakeup one thread tsleep()ing on the specified ident, on any cpu.
863 */
0cfcada1
MD
864void
865wakeup_one(void *ident)
866{
fc17ad60
MD
867 /* XXX potentially round-robin the first responding cpu */
868 _wakeup(ident, PWAKEUP_ENCODE(0, mycpu->gd_cpuid) | PWAKEUP_ONE);
da5fb9ef
MD
869}
870
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MD
871/*
872 * Wakeup threads tsleep()ing on the specified ident on the current cpu
873 * only.
874 */
875void
876wakeup_mycpu(void *ident)
877{
878 _wakeup(ident, PWAKEUP_MYCPU);
879}
880
881/*
882 * Wakeup one thread tsleep()ing on the specified ident on the current cpu
883 * only.
884 */
885void
886wakeup_mycpu_one(void *ident)
887{
888 /* XXX potentially round-robin the first responding cpu */
889 _wakeup(ident, PWAKEUP_MYCPU|PWAKEUP_ONE);
890}
891
892/*
893 * Wakeup all thread tsleep()ing on the specified ident on the specified cpu
894 * only.
895 */
896void
897wakeup_oncpu(globaldata_t gd, void *ident)
898{
1699d292 899#ifdef SMP
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MD
900 if (gd == mycpu) {
901 _wakeup(ident, PWAKEUP_MYCPU);
902 } else {
903 lwkt_send_ipiq2(gd, _wakeup, ident, PWAKEUP_MYCPU);
904 }
1699d292
MD
905#else
906 _wakeup(ident, PWAKEUP_MYCPU);
907#endif
b336a9b1
MD
908}
909
910/*
911 * Wakeup one thread tsleep()ing on the specified ident on the specified cpu
912 * only.
913 */
914void
915wakeup_oncpu_one(globaldata_t gd, void *ident)
916{
1699d292 917#ifdef SMP
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MD
918 if (gd == mycpu) {
919 _wakeup(ident, PWAKEUP_MYCPU | PWAKEUP_ONE);
920 } else {
921 lwkt_send_ipiq2(gd, _wakeup, ident, PWAKEUP_MYCPU | PWAKEUP_ONE);
922 }
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MD
923#else
924 _wakeup(ident, PWAKEUP_MYCPU | PWAKEUP_ONE);
925#endif
b336a9b1
MD
926}
927
928/*
929 * Wakeup all threads waiting on the specified ident that slept using
930 * the specified domain, on all cpus.
931 */
da5fb9ef
MD
932void
933wakeup_domain(void *ident, int domain)
934{
fc17ad60 935 _wakeup(ident, PWAKEUP_ENCODE(domain, mycpu->gd_cpuid));
da5fb9ef
MD
936}
937
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MD
938/*
939 * Wakeup one thread waiting on the specified ident that slept using
940 * the specified domain, on any cpu.
941 */
da5fb9ef
MD
942void
943wakeup_domain_one(void *ident, int domain)
944{
fc17ad60
MD
945 /* XXX potentially round-robin the first responding cpu */
946 _wakeup(ident, PWAKEUP_ENCODE(domain, mycpu->gd_cpuid) | PWAKEUP_ONE);
984263bc
MD
947}
948
949/*
344ad853
MD
950 * setrunnable()
951 *
952 * Make a process runnable. The MP lock must be held on call. This only
953 * has an effect if we are in SSLEEP. We only break out of the
9a379a4a 954 * tsleep if LWP_BREAKTSLEEP is set, otherwise we just fix-up the state.
37af14fe 955 *
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956 * NOTE: With the MP lock held we can only safely manipulate the process
957 * structure. We cannot safely manipulate the thread structure.
984263bc
MD
958 */
959void
9a379a4a 960setrunnable(struct lwp *lp)
984263bc 961{
344ad853
MD
962 crit_enter();
963 ASSERT_MP_LOCK_HELD(curthread);
2daf83b0
SS
964 if (lp->lwp_stat == LSSTOP)
965 lp->lwp_stat = LSSLEEP;
966 if (lp->lwp_stat == LSSLEEP && (lp->lwp_flag & LWP_BREAKTSLEEP))
08f2f1bb 967 unsleep_and_wakeup_thread(lp->lwp_thread);
344ad853 968 crit_exit();
984263bc
MD
969}
970
971/*
164b8401
SS
972 * The process is stopped due to some condition, usually because p_stat is
973 * set to SSTOP, but also possibly due to being traced.
fc17ad60 974 *
164b8401 975 * NOTE! If the caller sets SSTOP, the caller must also clear P_WAITED
344ad853
MD
976 * because the parent may check the child's status before the child actually
977 * gets to this routine.
978 *
9a379a4a 979 * This routine is called with the current lwp only, typically just
344ad853
MD
980 * before returning to userland.
981 *
9a379a4a 982 * Setting LWP_BREAKTSLEEP before entering the tsleep will cause a passive
344ad853 983 * SIGCONT to break out of the tsleep.
984263bc
MD
984 */
985void
9a379a4a 986tstop(void)
984263bc 987{
9a379a4a 988 struct lwp *lp = curthread->td_lwp;
7278a846 989 struct proc *p = lp->lwp_proc;
9a379a4a
SS
990
991 lp->lwp_flag |= LWP_BREAKTSLEEP;
7278a846
SS
992 lp->lwp_stat = LSSTOP;
993 crit_enter();
f33e8653
SS
994 /*
995 * If LWP_WSTOP is set, we were sleeping
996 * while our process was stopped. At this point
997 * we were already counted as stopped.
998 */
999 if ((lp->lwp_flag & LWP_WSTOP) == 0) {
1000 /*
1001 * If we're the last thread to stop, signal
1002 * our parent.
1003 */
1004 p->p_nstopped++;
1005 lp->lwp_flag |= LWP_WSTOP;
1006 if (p->p_nstopped == p->p_nthreads) {
1007 p->p_flag &= ~P_WAITED;
1008 wakeup(p->p_pptr);
1009 if ((p->p_pptr->p_sigacts->ps_flag & PS_NOCLDSTOP) == 0)
1010 ksignal(p->p_pptr, SIGCHLD);
1011 }
1012 }
9a379a4a 1013 tsleep(lp->lwp_proc, 0, "stop", 0);
7278a846
SS
1014 p->p_nstopped--;
1015 crit_exit();
26a0694b
MD
1016}
1017
a77ac49d
MD
1018/*
1019 * Yield / synchronous reschedule. This is a bit tricky because the trap
1020 * code might have set a lazy release on the switch function. Setting
1021 * P_PASSIVE_ACQ will ensure that the lazy release executes when we call
1022 * switch, and that we are given a greater chance of affinity with our
1023 * current cpu.
1024 *
1025 * We call lwkt_setpri_self() to rotate our thread to the end of the lwkt
1026 * run queue. lwkt_switch() will also execute any assigned passive release
1027 * (which usually calls release_curproc()), allowing a same/higher priority
1028 * process to be designated as the current process.
1029 *
1030 * While it is possible for a lower priority process to be designated,
1031 * it's call to lwkt_maybe_switch() in acquire_curproc() will likely
1032 * round-robin back to us and we will be able to re-acquire the current
1033 * process designation.
1034 */
1035void
1036uio_yield(void)
1037{
1038 struct thread *td = curthread;
1039 struct proc *p = td->td_proc;
1040
1041 lwkt_setpri_self(td->td_pri & TDPRI_MASK);
1042 if (p) {
1043 p->p_flag |= P_PASSIVE_ACQ;
1044 lwkt_switch();
1045 p->p_flag &= ~P_PASSIVE_ACQ;
1046 } else {
1047 lwkt_switch();
1048 }
1049}
1050
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1051/*
1052 * Compute a tenex style load average of a quantity on
1053 * 1, 5 and 15 minute intervals.
1054 */
c7e98b2f 1055static int loadav_count_runnable(struct lwp *p, void *data);
8fa76237 1056
984263bc
MD
1057static void
1058loadav(void *arg)
1059{
984263bc 1060 struct loadavg *avg;
8fa76237 1061 int i, nrun;
984263bc 1062
984263bc 1063 nrun = 0;
c7e98b2f 1064 alllwp_scan(loadav_count_runnable, &nrun);
8fa76237
MD
1065 avg = &averunnable;
1066 for (i = 0; i < 3; i++) {
984263bc
MD
1067 avg->ldavg[i] = (cexp[i] * avg->ldavg[i] +
1068 nrun * FSCALE * (FSCALE - cexp[i])) >> FSHIFT;
8fa76237 1069 }
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1070
1071 /*
1072 * Schedule the next update to occur after 5 seconds, but add a
1073 * random variation to avoid synchronisation with processes that
1074 * run at regular intervals.
1075 */
cddfb7bb 1076 callout_reset(&loadav_callout, hz * 4 + (int)(krandom() % (hz * 2 + 1)),
8fa76237
MD
1077 loadav, NULL);
1078}
1079
1080static int
c7e98b2f 1081loadav_count_runnable(struct lwp *lp, void *data)
8fa76237
MD
1082{
1083 int *nrunp = data;
1084 thread_t td;
1085
164b8401
SS
1086 switch (lp->lwp_stat) {
1087 case LSRUN:
08f2f1bb 1088 if ((td = lp->lwp_thread) == NULL)
8fa76237
MD
1089 break;
1090 if (td->td_flags & TDF_BLOCKED)
1091 break;
8fa76237
MD
1092 ++*nrunp;
1093 break;
1094 default:
1095 break;
1096 }
1097 return(0);
984263bc
MD
1098}
1099
1100/* ARGSUSED */
1101static void
6656cd91 1102sched_setup(void *dummy)
984263bc 1103{
984263bc 1104 callout_init(&loadav_callout);
35f9d051 1105 callout_init(&schedcpu_callout);
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MD
1106
1107 /* Kick off timeout driven events by calling first time. */
984263bc
MD
1108 schedcpu(NULL);
1109 loadav(NULL);
1110}
1111