__P(); not anymore in this directory
[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 $
f62004ad 40 * $DragonFly: src/sys/kern/kern_synch.c,v 1.20 2003/08/03 10:07:41 hmp 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>
26a0694b 53#include <sys/thread2.h>
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54#ifdef KTRACE
55#include <sys/uio.h>
56#include <sys/ktrace.h>
57#endif
f1d1c3fa 58#include <sys/xwait.h>
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59
60#include <machine/cpu.h>
61#include <machine/ipl.h>
62#include <machine/smp.h>
63
64static void sched_setup __P((void *dummy));
65SYSINIT(sched_setup, SI_SUB_KICK_SCHEDULER, SI_ORDER_FIRST, sched_setup, NULL)
66
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67int hogticks;
68int lbolt;
69int sched_quantum; /* Roundrobin scheduling quantum in ticks. */
17a9f566 70int ncpus;
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71
72static struct callout loadav_callout;
73
74struct loadavg averunnable =
75 { {0, 0, 0}, FSCALE }; /* load average, of runnable procs */
76/*
77 * Constants for averages over 1, 5, and 15 minutes
78 * when sampling at 5 second intervals.
79 */
80static fixpt_t cexp[3] = {
81 0.9200444146293232 * FSCALE, /* exp(-1/12) */
82 0.9834714538216174 * FSCALE, /* exp(-1/60) */
83 0.9944598480048967 * FSCALE, /* exp(-1/180) */
84};
85
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86static void endtsleep __P((void *));
87static void loadav __P((void *arg));
88static void maybe_resched __P((struct proc *chk));
89static void roundrobin __P((void *arg));
90static void schedcpu __P((void *arg));
91static void updatepri __P((struct proc *p));
8a8d5d85 92static void crit_panicints(void);
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93
94static int
95sysctl_kern_quantum(SYSCTL_HANDLER_ARGS)
96{
97 int error, new_val;
98
99 new_val = sched_quantum * tick;
100 error = sysctl_handle_int(oidp, &new_val, 0, req);
101 if (error != 0 || req->newptr == NULL)
102 return (error);
103 if (new_val < tick)
104 return (EINVAL);
105 sched_quantum = new_val / tick;
106 hogticks = 2 * sched_quantum;
107 return (0);
108}
109
110SYSCTL_PROC(_kern, OID_AUTO, quantum, CTLTYPE_INT|CTLFLAG_RW,
111 0, sizeof sched_quantum, sysctl_kern_quantum, "I", "");
112
984263bc 113/*
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114 * Arrange to reschedule if necessary by checking to see if the current
115 * process is on the highest priority user scheduling queue. This may
116 * be run from an interrupt so we have to follow any preemption chains
117 * back to the original process.
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118 */
119static void
26a0694b 120maybe_resched(struct proc *chk)
984263bc 121{
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122 struct proc *cur = lwkt_preempted_proc();
123
124 if (cur == NULL)
125 return;
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126
127 /*
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128 * Check the user queue (realtime, normal, idle). Lower numbers
129 * indicate higher priority queues. Lower numbers are also better
130 * for p_priority.
984263bc 131 */
26a0694b 132 if (chk->p_rtprio.type < cur->p_rtprio.type) {
984263bc 133 need_resched();
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134 } else if (chk->p_rtprio.type == cur->p_rtprio.type) {
135 if (chk->p_rtprio.type == RTP_PRIO_NORMAL) {
136 if (chk->p_priority / PPQ < cur->p_priority / PPQ)
137 need_resched();
138 } else {
139 if (chk->p_rtprio.prio < cur->p_rtprio.prio)
140 need_resched();
141 }
142 }
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143}
144
145int
146roundrobin_interval(void)
147{
148 return (sched_quantum);
149}
150
151/*
152 * Force switch among equal priority processes every 100ms.
153 */
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154#ifdef SMP
155
984263bc 156static void
cb973d15 157roundrobin_remote(void *arg)
984263bc 158{
8a8d5d85 159 struct proc *p = lwkt_preempted_proc();
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160 if (p == NULL || RTP_PRIO_NEED_RR(p->p_rtprio.type))
161 need_resched();
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162}
163
164#endif
165
166static void
167roundrobin(void *arg)
168{
169 struct proc *p = lwkt_preempted_proc();
8a8d5d85 170 if (p == NULL || RTP_PRIO_NEED_RR(p->p_rtprio.type))
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171 need_resched();
172#ifdef SMP
173 lwkt_send_ipiq_mask(mycpu->gd_other_cpus, roundrobin_remote, NULL);
984263bc 174#endif
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175 timeout(roundrobin, NULL, sched_quantum);
176}
177
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178#ifdef SMP
179
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180void
181resched_cpus(u_int32_t mask)
182{
183 lwkt_send_ipiq_mask(mask, roundrobin_remote, NULL);
184}
185
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186#endif
187
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188/*
189 * Constants for digital decay and forget:
190 * 90% of (p_estcpu) usage in 5 * loadav time
191 * 95% of (p_pctcpu) usage in 60 seconds (load insensitive)
192 * Note that, as ps(1) mentions, this can let percentages
193 * total over 100% (I've seen 137.9% for 3 processes).
194 *
195 * Note that schedclock() updates p_estcpu and p_cpticks asynchronously.
196 *
197 * We wish to decay away 90% of p_estcpu in (5 * loadavg) seconds.
198 * That is, the system wants to compute a value of decay such
199 * that the following for loop:
200 * for (i = 0; i < (5 * loadavg); i++)
201 * p_estcpu *= decay;
202 * will compute
203 * p_estcpu *= 0.1;
204 * for all values of loadavg:
205 *
206 * Mathematically this loop can be expressed by saying:
207 * decay ** (5 * loadavg) ~= .1
208 *
209 * The system computes decay as:
210 * decay = (2 * loadavg) / (2 * loadavg + 1)
211 *
212 * We wish to prove that the system's computation of decay
213 * will always fulfill the equation:
214 * decay ** (5 * loadavg) ~= .1
215 *
216 * If we compute b as:
217 * b = 2 * loadavg
218 * then
219 * decay = b / (b + 1)
220 *
221 * We now need to prove two things:
222 * 1) Given factor ** (5 * loadavg) ~= .1, prove factor == b/(b+1)
223 * 2) Given b/(b+1) ** power ~= .1, prove power == (5 * loadavg)
224 *
225 * Facts:
226 * For x close to zero, exp(x) =~ 1 + x, since
227 * exp(x) = 0! + x**1/1! + x**2/2! + ... .
228 * therefore exp(-1/b) =~ 1 - (1/b) = (b-1)/b.
229 * For x close to zero, ln(1+x) =~ x, since
230 * ln(1+x) = x - x**2/2 + x**3/3 - ... -1 < x < 1
231 * therefore ln(b/(b+1)) = ln(1 - 1/(b+1)) =~ -1/(b+1).
232 * ln(.1) =~ -2.30
233 *
234 * Proof of (1):
235 * Solve (factor)**(power) =~ .1 given power (5*loadav):
236 * solving for factor,
237 * ln(factor) =~ (-2.30/5*loadav), or
238 * factor =~ exp(-1/((5/2.30)*loadav)) =~ exp(-1/(2*loadav)) =
239 * exp(-1/b) =~ (b-1)/b =~ b/(b+1). QED
240 *
241 * Proof of (2):
242 * Solve (factor)**(power) =~ .1 given factor == (b/(b+1)):
243 * solving for power,
244 * power*ln(b/(b+1)) =~ -2.30, or
245 * power =~ 2.3 * (b + 1) = 4.6*loadav + 2.3 =~ 5*loadav. QED
246 *
247 * Actual power values for the implemented algorithm are as follows:
248 * loadav: 1 2 3 4
249 * power: 5.68 10.32 14.94 19.55
250 */
251
252/* calculations for digital decay to forget 90% of usage in 5*loadav sec */
253#define loadfactor(loadav) (2 * (loadav))
254#define decay_cpu(loadfac, cpu) (((loadfac) * (cpu)) / ((loadfac) + FSCALE))
255
256/* decay 95% of `p_pctcpu' in 60 seconds; see CCPU_SHIFT before changing */
257static fixpt_t ccpu = 0.95122942450071400909 * FSCALE; /* exp(-1/20) */
258SYSCTL_INT(_kern, OID_AUTO, ccpu, CTLFLAG_RD, &ccpu, 0, "");
259
260/* kernel uses `FSCALE', userland (SHOULD) use kern.fscale */
261static int fscale __unused = FSCALE;
262SYSCTL_INT(_kern, OID_AUTO, fscale, CTLFLAG_RD, 0, FSCALE, "");
263
264/*
265 * If `ccpu' is not equal to `exp(-1/20)' and you still want to use the
266 * faster/more-accurate formula, you'll have to estimate CCPU_SHIFT below
267 * and possibly adjust FSHIFT in "param.h" so that (FSHIFT >= CCPU_SHIFT).
268 *
269 * To estimate CCPU_SHIFT for exp(-1/20), the following formula was used:
270 * 1 - exp(-1/20) ~= 0.0487 ~= 0.0488 == 1 (fixed pt, *11* bits).
271 *
272 * If you don't want to bother with the faster/more-accurate formula, you
273 * can set CCPU_SHIFT to (FSHIFT + 1) which will use a slower/less-accurate
274 * (more general) method of calculating the %age of CPU used by a process.
275 */
276#define CCPU_SHIFT 11
277
278/*
279 * Recompute process priorities, every hz ticks.
280 */
281/* ARGSUSED */
282static void
26a0694b 283schedcpu(void *arg)
984263bc 284{
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285 fixpt_t loadfac = loadfactor(averunnable.ldavg[0]);
286 struct proc *p;
287 struct proc *curp;
288 int realstathz, s;
289
290 curp = lwkt_preempted_proc(); /* YYY temporary hack */
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291
292 realstathz = stathz ? stathz : hz;
f62004ad 293 FOREACH_PROC_IN_SYSTEM(p) {
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294 /*
295 * Increment time in/out of memory and sleep time
296 * (if sleeping). We ignore overflow; with 16-bit int's
297 * (remember them?) overflow takes 45 days.
298 */
299 p->p_swtime++;
300 if (p->p_stat == SSLEEP || p->p_stat == SSTOP)
301 p->p_slptime++;
302 p->p_pctcpu = (p->p_pctcpu * ccpu) >> FSHIFT;
303 /*
304 * If the process has slept the entire second,
305 * stop recalculating its priority until it wakes up.
306 */
307 if (p->p_slptime > 1)
308 continue;
309 s = splhigh(); /* prevent state changes and protect run queue */
310 /*
311 * p_pctcpu is only for ps.
312 */
313#if (FSHIFT >= CCPU_SHIFT)
314 p->p_pctcpu += (realstathz == 100)?
315 ((fixpt_t) p->p_cpticks) << (FSHIFT - CCPU_SHIFT):
316 100 * (((fixpt_t) p->p_cpticks)
317 << (FSHIFT - CCPU_SHIFT)) / realstathz;
318#else
319 p->p_pctcpu += ((FSCALE - ccpu) *
320 (p->p_cpticks * FSCALE / realstathz)) >> FSHIFT;
321#endif
322 p->p_cpticks = 0;
323 p->p_estcpu = decay_cpu(loadfac, p->p_estcpu);
324 resetpriority(p);
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325 splx(s);
326 }
327 wakeup((caddr_t)&lbolt);
328 timeout(schedcpu, (void *)0, hz);
329}
330
331/*
332 * Recalculate the priority of a process after it has slept for a while.
333 * For all load averages >= 1 and max p_estcpu of 255, sleeping for at
334 * least six times the loadfactor will decay p_estcpu to zero.
335 */
336static void
26a0694b 337updatepri(struct proc *p)
984263bc 338{
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339 unsigned int newcpu = p->p_estcpu;
340 fixpt_t loadfac = loadfactor(averunnable.ldavg[0]);
984263bc 341
26a0694b 342 if (p->p_slptime > 5 * loadfac) {
984263bc 343 p->p_estcpu = 0;
26a0694b 344 } else {
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345 p->p_slptime--; /* the first time was done in schedcpu */
346 while (newcpu && --p->p_slptime)
347 newcpu = decay_cpu(loadfac, newcpu);
348 p->p_estcpu = newcpu;
349 }
350 resetpriority(p);
351}
352
353/*
354 * We're only looking at 7 bits of the address; everything is
355 * aligned to 4, lots of things are aligned to greater powers
356 * of 2. Shift right by 8, i.e. drop the bottom 256 worth.
357 */
358#define TABLESIZE 128
0cfcada1 359static TAILQ_HEAD(slpquehead, thread) slpque[TABLESIZE];
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360#define LOOKUP(x) (((intptr_t)(x) >> 8) & (TABLESIZE - 1))
361
362/*
363 * During autoconfiguration or after a panic, a sleep will simply
364 * lower the priority briefly to allow interrupts, then return.
365 * The priority to be used (safepri) is machine-dependent, thus this
366 * value is initialized and maintained in the machine-dependent layers.
367 * This priority will typically be 0, or the lowest priority
368 * that is safe for use on the interrupt stack; it can be made
369 * higher to block network software interrupts after panics.
370 */
371int safepri;
372
373void
374sleepinit(void)
375{
376 int i;
377
378 sched_quantum = hz/10;
379 hogticks = 2 * sched_quantum;
380 for (i = 0; i < TABLESIZE; i++)
381 TAILQ_INIT(&slpque[i]);
382}
383
384/*
385 * General sleep call. Suspends the current process until a wakeup is
386 * performed on the specified identifier. The process will then be made
387 * runnable with the specified priority. Sleeps at most timo/hz seconds
377d4740 388 * (0 means no timeout). If flags includes PCATCH flag, signals are checked
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389 * before and after sleeping, else signals are not checked. Returns 0 if
390 * awakened, EWOULDBLOCK if the timeout expires. If PCATCH is set and a
391 * signal needs to be delivered, ERESTART is returned if the current system
392 * call should be restarted if possible, and EINTR is returned if the system
393 * call should be interrupted by the signal (return EINTR).
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394 *
395 * If the process has P_CURPROC set mi_switch() will not re-queue it to
396 * the userland scheduler queues because we are in a SSLEEP state. If
397 * we are not the current process then we have to remove ourselves from
398 * the scheduler queues.
399 *
400 * YYY priority now unused
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401 */
402int
377d4740 403tsleep(ident, flags, wmesg, timo)
984263bc 404 void *ident;
377d4740 405 int flags, timo;
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406 const char *wmesg;
407{
dadab5e9 408 struct thread *td = curthread;
0cfcada1 409 struct proc *p = td->td_proc; /* may be NULL */
377d4740 410 int s, sig = 0, catch = flags & PCATCH;
f1d1c3fa 411 int id = LOOKUP(ident);
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412 struct callout_handle thandle;
413
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414 /*
415 * NOTE: removed KTRPOINT, it could cause races due to blocking
416 * even in stable. Just scrap it for now.
417 */
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418 if (cold || panicstr) {
419 /*
420 * After a panic, or during autoconfiguration,
421 * just give interrupts a chance, then just return;
422 * don't run any other procs or panic below,
423 * in case this is the idle process and already asleep.
424 */
8a8d5d85 425 crit_panicints();
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426 return (0);
427 }
a2a5ad0d 428 KKASSERT(td != &mycpu->gd_idlethread); /* you must be kidding! */
8a8d5d85 429 s = splhigh();
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430 KASSERT(ident != NULL, ("tsleep: no ident"));
431 KASSERT(p == NULL || p->p_stat == SRUN, ("tsleep %p %s %d",
432 ident, wmesg, p->p_stat));
433
26a0694b 434 crit_enter();
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435 td->td_wchan = ident;
436 td->td_wmesg = wmesg;
26a0694b 437 if (p)
0cfcada1 438 p->p_slptime = 0;
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439 lwkt_deschedule_self();
440 TAILQ_INSERT_TAIL(&slpque[id], td, td_threadq);
984263bc 441 if (timo)
0cfcada1 442 thandle = timeout(endtsleep, (void *)td, timo);
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443 /*
444 * We put ourselves on the sleep queue and start our timeout
445 * before calling CURSIG, as we could stop there, and a wakeup
446 * or a SIGCONT (or both) could occur while we were stopped.
447 * A SIGCONT would cause us to be marked as SSLEEP
448 * without resuming us, thus we must be ready for sleep
449 * when CURSIG is called. If the wakeup happens while we're
a2a5ad0d 450 * stopped, td->td_wchan will be 0 upon return from CURSIG.
984263bc 451 */
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452 if (p) {
453 if (catch) {
454 p->p_flag |= P_SINTR;
455 if ((sig = CURSIG(p))) {
26a0694b 456 if (td->td_wchan) {
0cfcada1 457 unsleep(td);
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458 lwkt_schedule_self();
459 }
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460 p->p_stat = SRUN;
461 goto resume;
462 }
a2a5ad0d 463 if (td->td_wchan == NULL) {
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464 catch = 0;
465 goto resume;
466 }
467 } else {
468 sig = 0;
984263bc 469 }
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470
471 /*
472 * If we are not the current process we have to remove ourself
473 * from the run queue.
474 */
475 KASSERT(p->p_stat == SRUN, ("PSTAT NOT SRUN %d %d", p->p_pid, p->p_stat));
476 /*
477 * If this is the current 'user' process schedule another one.
478 */
479 clrrunnable(p, SSLEEP);
0cfcada1 480 p->p_stats->p_ru.ru_nvcsw++;
a2a5ad0d 481 KKASSERT(td->td_release || (p->p_flag & P_CURPROC) == 0);
0cfcada1 482 mi_switch();
26a0694b 483 KASSERT(p->p_stat == SRUN, ("tsleep: stat not srun"));
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484 } else {
485 lwkt_switch();
486 }
984263bc 487resume:
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488 crit_exit();
489 if (p)
0cfcada1 490 p->p_flag &= ~P_SINTR;
984263bc 491 splx(s);
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492 if (td->td_flags & TDF_TIMEOUT) {
493 td->td_flags &= ~TDF_TIMEOUT;
494 if (sig == 0)
984263bc 495 return (EWOULDBLOCK);
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496 } else if (timo) {
497 untimeout(endtsleep, (void *)td, thandle);
498 }
499 if (p) {
500 if (catch && (sig != 0 || (sig = CURSIG(p)))) {
501 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig))
502 return (EINTR);
503 return (ERESTART);
984263bc 504 }
984263bc 505 }
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506 return (0);
507}
508
984263bc 509/*
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510 * Implement the timeout for tsleep. We interlock against
511 * wchan when setting TDF_TIMEOUT. For processes we remove
512 * the sleep if the process is stopped rather then sleeping,
513 * so it remains stopped.
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514 */
515static void
0cfcada1 516endtsleep(void *arg)
984263bc 517{
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518 thread_t td = arg;
519 struct proc *p;
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520 int s;
521
984263bc 522 s = splhigh();
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523 if (td->td_wchan) {
524 td->td_flags |= TDF_TIMEOUT;
525 if ((p = td->td_proc) != NULL) {
526 if (p->p_stat == SSLEEP)
527 setrunnable(p);
528 else
529 unsleep(td);
530 } else {
531 unsleep(td);
532 lwkt_schedule(td);
533 }
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534 }
535 splx(s);
536}
537
538/*
539 * Remove a process from its wait queue
540 */
541void
0cfcada1 542unsleep(struct thread *td)
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543{
544 int s;
545
546 s = splhigh();
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547 if (td->td_wchan) {
548#if 0
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549 if (p->p_flag & P_XSLEEP) {
550 struct xwait *w = p->p_wchan;
551 TAILQ_REMOVE(&w->waitq, p, p_procq);
552 p->p_flag &= ~P_XSLEEP;
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553 } else
554#endif
555 TAILQ_REMOVE(&slpque[LOOKUP(td->td_wchan)], td, td_threadq);
556 td->td_wchan = NULL;
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557 }
558 splx(s);
559}
560
0cfcada1 561#if 0
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562/*
563 * Make all processes sleeping on the explicit lock structure runnable.
564 */
565void
566xwakeup(struct xwait *w)
567{
568 struct proc *p;
569 int s;
570
571 s = splhigh();
572 ++w->gen;
573 while ((p = TAILQ_FIRST(&w->waitq)) != NULL) {
574 TAILQ_REMOVE(&w->waitq, p, p_procq);
575 KASSERT(p->p_wchan == w && (p->p_flag & P_XSLEEP),
576 ("xwakeup: wchan mismatch for %p (%p/%p) %08x", p, p->p_wchan, w, p->p_flag & P_XSLEEP));
577 p->p_wchan = NULL;
578 p->p_flag &= ~P_XSLEEP;
579 if (p->p_stat == SSLEEP) {
580 /* OPTIMIZED EXPANSION OF setrunnable(p); */
581 if (p->p_slptime > 1)
582 updatepri(p);
583 p->p_slptime = 0;
584 p->p_stat = SRUN;
585 if (p->p_flag & P_INMEM) {
586 setrunqueue(p);
587 maybe_resched(p);
588 } else {
589 p->p_flag |= P_SWAPINREQ;
590 wakeup((caddr_t)&proc0);
591 }
592 }
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593 }
594 splx(s);
595}
0cfcada1 596#endif
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597
598/*
599 * Make all processes sleeping on the specified identifier runnable.
600 */
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601static void
602_wakeup(void *ident, int count)
984263bc 603{
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604 struct slpquehead *qp;
605 struct thread *td;
606 struct thread *ntd;
607 struct proc *p;
984263bc 608 int s;
f1d1c3fa 609 int id = LOOKUP(ident);
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610
611 s = splhigh();
f1d1c3fa 612 qp = &slpque[id];
984263bc 613restart:
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614 for (td = TAILQ_FIRST(qp); td != NULL; td = ntd) {
615 ntd = TAILQ_NEXT(td, td_threadq);
616 if (td->td_wchan == ident) {
617 TAILQ_REMOVE(qp, td, td_threadq);
618 td->td_wchan = NULL;
619 if ((p = td->td_proc) != NULL && p->p_stat == SSLEEP) {
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620 /* OPTIMIZED EXPANSION OF setrunnable(p); */
621 if (p->p_slptime > 1)
622 updatepri(p);
623 p->p_slptime = 0;
624 p->p_stat = SRUN;
625 if (p->p_flag & P_INMEM) {
626 setrunqueue(p);
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627 if (p->p_flag & P_CURPROC)
628 maybe_resched(p);
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629 } else {
630 p->p_flag |= P_SWAPINREQ;
631 wakeup((caddr_t)&proc0);
632 }
633 /* END INLINE EXPANSION */
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634 } else if (p == NULL) {
635 lwkt_schedule(td);
984263bc 636 }
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637 if (--count == 0)
638 break;
639 goto restart;
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640 }
641 }
642 splx(s);
643}
644
984263bc 645void
0cfcada1 646wakeup(void *ident)
984263bc 647{
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648 _wakeup(ident, 0);
649}
984263bc 650
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651void
652wakeup_one(void *ident)
653{
654 _wakeup(ident, 1);
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655}
656
657/*
658 * The machine independent parts of mi_switch().
659 * Must be called at splstatclock() or higher.
660 */
661void
662mi_switch()
663{
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664 struct thread *td = curthread;
665 struct proc *p = td->td_proc; /* XXX */
666 struct rlimit *rlim;
984263bc 667 int x;
d16a8831 668 u_int64_t ttime;
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669
670 /*
671 * XXX this spl is almost unnecessary. It is partly to allow for
672 * sloppy callers that don't do it (issignal() via CURSIG() is the
673 * main offender). It is partly to work around a bug in the i386
674 * cpu_switch() (the ipl is not preserved). We ran for years
675 * without it. I think there was only a interrupt latency problem.
676 * The main caller, tsleep(), does an splx() a couple of instructions
677 * after calling here. The buggy caller, issignal(), usually calls
678 * here at spl0() and sometimes returns at splhigh(). The process
679 * then runs for a little too long at splhigh(). The ipl gets fixed
680 * when the process returns to user mode (or earlier).
681 *
682 * It would probably be better to always call here at spl0(). Callers
683 * are prepared to give up control to another process, so they must
684 * be prepared to be interrupted. The clock stuff here may not
685 * actually need splstatclock().
686 */
687 x = splstatclock();
8ad65e08 688 clear_resched();
984263bc 689
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690 /*
691 * Check if the process exceeds its cpu resource allocation.
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692 * If over max, kill it. Time spent in interrupts is not
693 * included. YYY 64 bit match is expensive. Ick.
984263bc 694 */
d16a8831 695 ttime = td->td_sticks + td->td_uticks;
984263bc 696 if (p->p_stat != SZOMB && p->p_limit->p_cpulimit != RLIM_INFINITY &&
d16a8831 697 ttime > p->p_limit->p_cpulimit) {
984263bc 698 rlim = &p->p_rlimit[RLIMIT_CPU];
d16a8831 699 if (ttime / (rlim_t)1000000 >= rlim->rlim_max) {
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700 killproc(p, "exceeded maximum CPU limit");
701 } else {
702 psignal(p, SIGXCPU);
703 if (rlim->rlim_cur < rlim->rlim_max) {
704 /* XXX: we should make a private copy */
705 rlim->rlim_cur += 5;
706 }
707 }
708 }
709
710 /*
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711 * Pick a new current process and record its start time. If we
712 * are in a SSTOPped state we deschedule ourselves. YYY this needs
713 * to be cleaned up, remember that LWKTs stay on their run queue
714 * which works differently then the user scheduler which removes
715 * the process from the runq when it runs it.
984263bc 716 */
12e4aaff 717 mycpu->gd_cnt.v_swtch++;
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718 if (p->p_stat == SSTOP)
719 lwkt_deschedule_self();
8ad65e08 720 lwkt_switch();
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721
722 splx(x);
723}
724
725/*
726 * Change process state to be runnable,
727 * placing it on the run queue if it is in memory,
728 * and awakening the swapper if it isn't in memory.
729 */
730void
0cfcada1 731setrunnable(struct proc *p)
984263bc 732{
0cfcada1 733 int s;
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734
735 s = splhigh();
736 switch (p->p_stat) {
737 case 0:
738 case SRUN:
739 case SZOMB:
740 default:
741 panic("setrunnable");
742 case SSTOP:
743 case SSLEEP:
0cfcada1 744 unsleep(p->p_thread); /* e.g. when sending signals */
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745 break;
746
747 case SIDL:
748 break;
749 }
750 p->p_stat = SRUN;
751 if (p->p_flag & P_INMEM)
752 setrunqueue(p);
753 splx(s);
754 if (p->p_slptime > 1)
755 updatepri(p);
756 p->p_slptime = 0;
757 if ((p->p_flag & P_INMEM) == 0) {
758 p->p_flag |= P_SWAPINREQ;
759 wakeup((caddr_t)&proc0);
26a0694b 760 } else {
984263bc 761 maybe_resched(p);
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762 }
763}
764
765/*
766 * Change the process state to NOT be runnable, removing it from the run
767 * queue. If P_CURPROC is not set and we are in SRUN the process is on the
768 * run queue (If P_INMEM is not set then it isn't because it is swapped).
769 */
770void
771clrrunnable(struct proc *p, int stat)
772{
773 int s;
774
775 s = splhigh();
776 switch(p->p_stat) {
777 case SRUN:
a2a5ad0d 778 if (p->p_flag & P_ONRUNQ)
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779 remrunqueue(p);
780 break;
781 default:
782 break;
783 }
784 p->p_stat = stat;
785 splx(s);
786}
787
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788/*
789 * Compute the priority of a process when running in user mode.
790 * Arrange to reschedule if the resulting priority is better
791 * than that of the current process.
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792 *
793 * YYY real time / idle procs do not use p_priority XXX
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794 */
795void
26a0694b 796resetpriority(struct proc *p)
984263bc 797{
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798 unsigned int newpriority;
799 int opq;
800 int npq;
801
802 if (p->p_rtprio.type != RTP_PRIO_NORMAL)
803 return;
804 newpriority = PUSER + p->p_estcpu / INVERSE_ESTCPU_WEIGHT +
805 NICE_WEIGHT * p->p_nice;
806 newpriority = min(newpriority, MAXPRI);
26a0694b 807 npq = newpriority / PPQ;
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808 crit_enter();
809 opq = p->p_priority / PPQ;
a2a5ad0d 810 if (p->p_stat == SRUN && (p->p_flag & P_ONRUNQ) && opq != npq) {
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811 /*
812 * We have to move the process to another queue
813 */
814 remrunqueue(p);
815 p->p_priority = newpriority;
816 setrunqueue(p);
817 } else {
818 /*
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819 * We can just adjust the priority and it will be picked
820 * up later.
26a0694b 821 */
a2a5ad0d 822 KKASSERT(opq == npq || (p->p_flag & P_ONRUNQ) == 0);
26a0694b 823 p->p_priority = newpriority;
984263bc 824 }
d6dd2af9 825 crit_exit();
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826 maybe_resched(p);
827}
828
829/*
830 * Compute a tenex style load average of a quantity on
831 * 1, 5 and 15 minute intervals.
832 */
833static void
834loadav(void *arg)
835{
836 int i, nrun;
837 struct loadavg *avg;
838 struct proc *p;
839
840 avg = &averunnable;
841 nrun = 0;
f62004ad 842 FOREACH_PROC_IN_SYSTEM(p) {
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843 switch (p->p_stat) {
844 case SRUN:
845 case SIDL:
846 nrun++;
847 }
848 }
849 for (i = 0; i < 3; i++)
850 avg->ldavg[i] = (cexp[i] * avg->ldavg[i] +
851 nrun * FSCALE * (FSCALE - cexp[i])) >> FSHIFT;
852
853 /*
854 * Schedule the next update to occur after 5 seconds, but add a
855 * random variation to avoid synchronisation with processes that
856 * run at regular intervals.
857 */
858 callout_reset(&loadav_callout, hz * 4 + (int)(random() % (hz * 2 + 1)),
859 loadav, NULL);
860}
861
862/* ARGSUSED */
863static void
864sched_setup(dummy)
865 void *dummy;
866{
867
868 callout_init(&loadav_callout);
869
870 /* Kick off timeout driven events by calling first time. */
871 roundrobin(NULL);
872 schedcpu(NULL);
873 loadav(NULL);
874}
875
876/*
877 * We adjust the priority of the current process. The priority of
878 * a process gets worse as it accumulates CPU time. The cpu usage
879 * estimator (p_estcpu) is increased here. resetpriority() will
880 * compute a different priority each time p_estcpu increases by
881 * INVERSE_ESTCPU_WEIGHT
882 * (until MAXPRI is reached). The cpu usage estimator ramps up
883 * quite quickly when the process is running (linearly), and decays
884 * away exponentially, at a rate which is proportionally slower when
885 * the system is busy. The basic principle is that the system will
886 * 90% forget that the process used a lot of CPU time in 5 * loadav
887 * seconds. This causes the system to favor processes which haven't
888 * run much recently, and to round-robin among other processes.
889 */
890void
891schedclock(p)
892 struct proc *p;
893{
894
895 p->p_cpticks++;
896 p->p_estcpu = ESTCPULIM(p->p_estcpu + 1);
26a0694b 897 if ((p->p_estcpu % INVERSE_ESTCPU_WEIGHT) == 0)
984263bc 898 resetpriority(p);
984263bc 899}
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900
901static
902void
903crit_panicints(void)
904{
905 int s;
906 int cpri;
907
908 s = splhigh();
909 cpri = crit_panic_save();
910 splx(safepri);
911 crit_panic_restore(cpri);
912 splx(s);
913}
914