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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 $
40 * $DragonFly: src/sys/kern/kern_synch.c,v 1.91 2008/09/09 04:06:13 dillon Exp $
43 #include "opt_ktrace.h"
45 #include <sys/param.h>
46 #include <sys/systm.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>
56 #include <sys/ktrace.h>
58 #include <sys/xwait.h>
60 #include <sys/serialize.h>
62 #include <sys/signal2.h>
63 #include <sys/thread2.h>
64 #include <sys/spinlock2.h>
65 #include <sys/mutex2.h>
67 #include <machine/cpu.h>
68 #include <machine/smp.h>
70 TAILQ_HEAD(tslpque, thread);
72 static void sched_setup (void *dummy);
73 SYSINIT(sched_setup, SI_SUB_KICK_SCHEDULER, SI_ORDER_FIRST, sched_setup, NULL)
78 int sched_quantum; /* Roundrobin scheduling quantum in ticks. */
80 int ncpus2, ncpus2_shift, ncpus2_mask; /* note: mask not cpumask_t */
81 int ncpus_fit, ncpus_fit_mask; /* note: mask not cpumask_t */
84 int tsleep_crypto_dump = 0;
86 static struct callout loadav_callout;
87 static struct callout schedcpu_callout;
88 MALLOC_DEFINE(M_TSLEEP, "tslpque", "tsleep queues");
90 #define __DEALL(ident) __DEQUALIFY(void *, ident)
92 #if !defined(KTR_TSLEEP)
93 #define KTR_TSLEEP KTR_ALL
95 KTR_INFO_MASTER(tsleep);
96 KTR_INFO(KTR_TSLEEP, tsleep, tsleep_beg, 0, "tsleep enter %p", sizeof(void *));
97 KTR_INFO(KTR_TSLEEP, tsleep, tsleep_end, 1, "tsleep exit", 0);
98 KTR_INFO(KTR_TSLEEP, tsleep, wakeup_beg, 2, "wakeup enter %p", sizeof(void *));
99 KTR_INFO(KTR_TSLEEP, tsleep, wakeup_end, 3, "wakeup exit", 0);
100 KTR_INFO(KTR_TSLEEP, tsleep, ilockfail, 4, "interlock failed %p", sizeof(void *));
102 #define logtsleep1(name) KTR_LOG(tsleep_ ## name)
103 #define logtsleep2(name, val) KTR_LOG(tsleep_ ## name, val)
105 struct loadavg averunnable =
106 { {0, 0, 0}, FSCALE }; /* load average, of runnable procs */
108 * Constants for averages over 1, 5, and 15 minutes
109 * when sampling at 5 second intervals.
111 static fixpt_t cexp[3] = {
112 0.9200444146293232 * FSCALE, /* exp(-1/12) */
113 0.9834714538216174 * FSCALE, /* exp(-1/60) */
114 0.9944598480048967 * FSCALE, /* exp(-1/180) */
117 static void endtsleep (void *);
118 static void loadav (void *arg);
119 static void schedcpu (void *arg);
121 static void tsleep_wakeup_remote(struct thread *td);
125 * Adjust the scheduler quantum. The quantum is specified in microseconds.
126 * Note that 'tick' is in microseconds per tick.
129 sysctl_kern_quantum(SYSCTL_HANDLER_ARGS)
133 new_val = sched_quantum * ustick;
134 error = sysctl_handle_int(oidp, &new_val, 0, req);
135 if (error != 0 || req->newptr == NULL)
137 if (new_val < ustick)
139 sched_quantum = new_val / ustick;
140 hogticks = 2 * sched_quantum;
144 SYSCTL_PROC(_kern, OID_AUTO, quantum, CTLTYPE_INT|CTLFLAG_RW,
145 0, sizeof sched_quantum, sysctl_kern_quantum, "I", "");
148 * If `ccpu' is not equal to `exp(-1/20)' and you still want to use the
149 * faster/more-accurate formula, you'll have to estimate CCPU_SHIFT below
150 * and possibly adjust FSHIFT in "param.h" so that (FSHIFT >= CCPU_SHIFT).
152 * To estimate CCPU_SHIFT for exp(-1/20), the following formula was used:
153 * 1 - exp(-1/20) ~= 0.0487 ~= 0.0488 == 1 (fixed pt, *11* bits).
155 * If you don't want to bother with the faster/more-accurate formula, you
156 * can set CCPU_SHIFT to (FSHIFT + 1) which will use a slower/less-accurate
157 * (more general) method of calculating the %age of CPU used by a process.
159 * decay 95% of `lwp_pctcpu' in 60 seconds; see CCPU_SHIFT before changing
161 #define CCPU_SHIFT 11
163 static fixpt_t ccpu = 0.95122942450071400909 * FSCALE; /* exp(-1/20) */
164 SYSCTL_INT(_kern, OID_AUTO, ccpu, CTLFLAG_RD, &ccpu, 0, "");
167 * kernel uses `FSCALE', userland (SHOULD) use kern.fscale
169 int fscale __unused = FSCALE; /* exported to systat */
170 SYSCTL_INT(_kern, OID_AUTO, fscale, CTLFLAG_RD, 0, FSCALE, "");
173 * Recompute process priorities, once a second.
175 * Since the userland schedulers are typically event oriented, if the
176 * estcpu calculation at wakeup() time is not sufficient to make a
177 * process runnable relative to other processes in the system we have
178 * a 1-second recalc to help out.
180 * This code also allows us to store sysclock_t data in the process structure
181 * without fear of an overrun, since sysclock_t are guarenteed to hold
182 * several seconds worth of count.
184 * WARNING! callouts can preempt normal threads. However, they will not
185 * preempt a thread holding a spinlock so we *can* safely use spinlocks.
187 static int schedcpu_stats(struct proc *p, void *data __unused);
188 static int schedcpu_resource(struct proc *p, void *data __unused);
193 allproc_scan(schedcpu_stats, NULL);
194 allproc_scan(schedcpu_resource, NULL);
195 wakeup((caddr_t)&lbolt);
196 wakeup((caddr_t)&lbolt_syncer);
197 callout_reset(&schedcpu_callout, hz, schedcpu, NULL);
201 * General process statistics once a second
204 schedcpu_stats(struct proc *p, void *data __unused)
209 * Threads may not be completely set up if process in SIDL state.
211 if (p->p_stat == SIDL)
215 lwkt_gettoken(&p->p_token);
218 FOREACH_LWP_IN_PROC(lp, p) {
219 if (lp->lwp_stat == LSSLEEP)
223 * Only recalculate processes that are active or have slept
224 * less then 2 seconds. The schedulers understand this.
226 if (lp->lwp_slptime <= 1) {
227 p->p_usched->recalculate(lp);
229 lp->lwp_pctcpu = (lp->lwp_pctcpu * ccpu) >> FSHIFT;
232 lwkt_reltoken(&p->p_token);
238 * Resource checks. XXX break out since ksignal/killproc can block,
239 * limiting us to one process killed per second. There is probably
243 schedcpu_resource(struct proc *p, void *data __unused)
248 if (p->p_stat == SIDL)
252 lwkt_gettoken(&p->p_token);
254 if (p->p_stat == SZOMB || p->p_limit == NULL) {
255 lwkt_reltoken(&p->p_token);
261 FOREACH_LWP_IN_PROC(lp, p) {
263 * We may have caught an lp in the middle of being
264 * created, lwp_thread can be NULL.
266 if (lp->lwp_thread) {
267 ttime += lp->lwp_thread->td_sticks;
268 ttime += lp->lwp_thread->td_uticks;
272 switch(plimit_testcpulimit(p->p_limit, ttime)) {
273 case PLIMIT_TESTCPU_KILL:
274 killproc(p, "exceeded maximum CPU limit");
276 case PLIMIT_TESTCPU_XCPU:
277 if ((p->p_flag & P_XCPU) == 0) {
285 lwkt_reltoken(&p->p_token);
291 * This is only used by ps. Generate a cpu percentage use over
292 * a period of one second.
297 updatepcpu(struct lwp *lp, int cpticks, int ttlticks)
302 acc = (cpticks << FSHIFT) / ttlticks;
303 if (ttlticks >= ESTCPUFREQ) {
304 lp->lwp_pctcpu = acc;
306 remticks = ESTCPUFREQ - ttlticks;
307 lp->lwp_pctcpu = (acc * ttlticks + lp->lwp_pctcpu * remticks) /
313 * tsleep/wakeup hash table parameters. Try to find the sweet spot for
314 * like addresses being slept on.
316 #define TABLESIZE 1024
317 #define LOOKUP(x) (((intptr_t)(x) >> 6) & (TABLESIZE - 1))
319 static cpumask_t slpque_cpumasks[TABLESIZE];
322 * General scheduler initialization. We force a reschedule 25 times
323 * a second by default. Note that cpu0 is initialized in early boot and
324 * cannot make any high level calls.
326 * Each cpu has its own sleep queue.
329 sleep_gdinit(globaldata_t gd)
331 static struct tslpque slpque_cpu0[TABLESIZE];
334 if (gd->gd_cpuid == 0) {
335 sched_quantum = (hz + 24) / 25;
336 hogticks = 2 * sched_quantum;
338 gd->gd_tsleep_hash = slpque_cpu0;
340 gd->gd_tsleep_hash = kmalloc(sizeof(slpque_cpu0),
341 M_TSLEEP, M_WAITOK | M_ZERO);
343 for (i = 0; i < TABLESIZE; ++i)
344 TAILQ_INIT(&gd->gd_tsleep_hash[i]);
348 * This is a dandy function that allows us to interlock tsleep/wakeup
349 * operations with unspecified upper level locks, such as lockmgr locks,
350 * simply by holding a critical section. The sequence is:
352 * (acquire upper level lock)
353 * tsleep_interlock(blah)
354 * (release upper level lock)
357 * Basically this functions queues us on the tsleep queue without actually
358 * descheduling us. When tsleep() is later called with PINTERLOCK it
359 * assumes the thread was already queued, otherwise it queues it there.
361 * Thus it is possible to receive the wakeup prior to going to sleep and
362 * the race conditions are covered.
365 _tsleep_interlock(globaldata_t gd, const volatile void *ident, int flags)
367 thread_t td = gd->gd_curthread;
370 crit_enter_quick(td);
371 if (td->td_flags & TDF_TSLEEPQ) {
372 id = LOOKUP(td->td_wchan);
373 TAILQ_REMOVE(&gd->gd_tsleep_hash[id], td, td_sleepq);
374 if (TAILQ_FIRST(&gd->gd_tsleep_hash[id]) == NULL)
375 atomic_clear_cpumask(&slpque_cpumasks[id], gd->gd_cpumask);
377 td->td_flags |= TDF_TSLEEPQ;
380 TAILQ_INSERT_TAIL(&gd->gd_tsleep_hash[id], td, td_sleepq);
381 atomic_set_cpumask(&slpque_cpumasks[id], gd->gd_cpumask);
382 td->td_wchan = ident;
383 td->td_wdomain = flags & PDOMAIN_MASK;
388 tsleep_interlock(const volatile void *ident, int flags)
390 _tsleep_interlock(mycpu, ident, flags);
394 * Remove thread from sleepq. Must be called with a critical section held.
397 _tsleep_remove(thread_t td)
399 globaldata_t gd = mycpu;
402 KKASSERT(td->td_gd == gd);
403 if (td->td_flags & TDF_TSLEEPQ) {
404 td->td_flags &= ~TDF_TSLEEPQ;
405 id = LOOKUP(td->td_wchan);
406 TAILQ_REMOVE(&gd->gd_tsleep_hash[id], td, td_sleepq);
407 if (TAILQ_FIRST(&gd->gd_tsleep_hash[id]) == NULL)
408 atomic_clear_cpumask(&slpque_cpumasks[id], gd->gd_cpumask);
415 tsleep_remove(thread_t td)
421 * This function removes a thread from the tsleep queue and schedules
422 * it. This function may act asynchronously. The target thread may be
423 * sleeping on a different cpu.
425 * This function mus be called while in a critical section but if the
426 * target thread is sleeping on a different cpu we cannot safely probe
429 * This function is only called from a different cpu via setrunnable()
430 * when the thread is in a known sleep. However, multiple wakeups are
431 * possible and we must hold the td to prevent a race against the thread
436 _tsleep_wakeup(struct thread *td)
439 globaldata_t gd = mycpu;
441 if (td->td_gd != gd) {
443 lwkt_send_ipiq(td->td_gd, (ipifunc1_t)tsleep_wakeup_remote, td);
448 if (td->td_flags & TDF_TSLEEP_DESCHEDULED) {
449 td->td_flags &= ~TDF_TSLEEP_DESCHEDULED;
457 tsleep_wakeup_remote(struct thread *td)
466 * General sleep call. Suspends the current process until a wakeup is
467 * performed on the specified identifier. The process will then be made
468 * runnable with the specified priority. Sleeps at most timo/hz seconds
469 * (0 means no timeout). If flags includes PCATCH flag, signals are checked
470 * before and after sleeping, else signals are not checked. Returns 0 if
471 * awakened, EWOULDBLOCK if the timeout expires. If PCATCH is set and a
472 * signal needs to be delivered, ERESTART is returned if the current system
473 * call should be restarted if possible, and EINTR is returned if the system
474 * call should be interrupted by the signal (return EINTR).
476 * Note that if we are a process, we release_curproc() before messing with
477 * the LWKT scheduler.
479 * During autoconfiguration or after a panic, a sleep will simply
480 * lower the priority briefly to allow interrupts, then return.
483 tsleep(const volatile void *ident, int flags, const char *wmesg, int timo)
485 struct thread *td = curthread;
486 struct lwp *lp = td->td_lwp;
487 struct proc *p = td->td_proc; /* may be NULL */
494 struct callout thandle;
497 * NOTE: removed KTRPOINT, it could cause races due to blocking
498 * even in stable. Just scrap it for now.
500 if (!tsleep_crypto_dump && (tsleep_now_works == 0 || panicstr)) {
502 * After a panic, or before we actually have an operational
503 * softclock, just give interrupts a chance, then just return;
505 * don't run any other procs or panic below,
506 * in case this is the idle process and already asleep.
510 lwkt_setpri_self(safepri);
512 lwkt_setpri_self(oldpri);
515 logtsleep2(tsleep_beg, ident);
517 KKASSERT(td != &gd->gd_idlethread); /* you must be kidding! */
520 * NOTE: all of this occurs on the current cpu, including any
521 * callout-based wakeups, so a critical section is a sufficient
524 * The entire sequence through to where we actually sleep must
525 * run without breaking the critical section.
527 catch = flags & PCATCH;
531 crit_enter_quick(td);
533 KASSERT(ident != NULL, ("tsleep: no ident"));
534 KASSERT(lp == NULL ||
535 lp->lwp_stat == LSRUN || /* Obvious */
536 lp->lwp_stat == LSSTOP, /* Set in tstop */
538 ident, wmesg, lp->lwp_stat));
541 * We interlock the sleep queue if the caller has not already done
542 * it for us. This must be done before we potentially acquire any
543 * tokens or we can loose the wakeup.
545 if ((flags & PINTERLOCKED) == 0) {
547 _tsleep_interlock(gd, ident, flags);
551 * Setup for the current process (if this is a process).
553 * We hold the process token if lp && catch. The resume
554 * code will release it.
559 * Early termination if PCATCH was set and a
560 * signal is pending, interlocked with the
563 * Early termination only occurs when tsleep() is
564 * entered while in a normal LSRUN state.
566 lwkt_gettoken(&p->p_token);
567 if ((sig = CURSIG(lp)) != 0)
571 * Early termination if PCATCH was set and a
572 * mailbox signal was possibly delivered prior to
573 * the system call even being made, in order to
574 * allow the user to interlock without having to
575 * make additional system calls.
577 if (p->p_flag & P_MAILBOX)
581 * Causes ksignal to wake us up if a signal is
582 * received (interlocked with p->p_token).
584 lp->lwp_flag |= LWP_SINTR;
591 * Make sure the current process has been untangled from
592 * the userland scheduler and initialize slptime to start
596 p->p_usched->release_curproc(lp);
601 * If the interlocked flag is set but our cpu bit in the slpqueue
602 * is no longer set, then a wakeup was processed inbetween the
603 * tsleep_interlock() (ours or the callers), and here. This can
604 * occur under numerous circumstances including when we release the
607 * Extreme loads can cause the sending of an IPI (e.g. wakeup()'s)
608 * to process incoming IPIs, thus draining incoming wakeups.
610 if ((td->td_flags & TDF_TSLEEPQ) == 0) {
611 logtsleep2(ilockfail, ident);
616 * scheduling is blocked while in a critical section. Coincide
617 * the descheduled-by-tsleep flag with the descheduling of the
620 * The timer callout is localized on our cpu and interlocked by
621 * our critical section.
623 lwkt_deschedule_self(td);
624 td->td_flags |= TDF_TSLEEP_DESCHEDULED;
625 td->td_wmesg = wmesg;
628 * Setup the timeout, if any. The timeout is only operable while
629 * the thread is flagged descheduled.
631 KKASSERT((td->td_flags & TDF_TIMEOUT) == 0);
633 callout_init_mp(&thandle);
634 callout_reset(&thandle, timo, endtsleep, td);
642 * Ok, we are sleeping. Place us in the SSLEEP state.
644 KKASSERT((lp->lwp_flag & LWP_ONRUNQ) == 0);
646 * tstop() sets LSSTOP, so don't fiddle with that.
648 if (lp->lwp_stat != LSSTOP)
649 lp->lwp_stat = LSSLEEP;
650 lp->lwp_ru.ru_nvcsw++;
652 td->td_flags &= ~TDF_TSLEEP_DESCHEDULED;
655 * And when we are woken up, put us back in LSRUN. If we
656 * slept for over a second, recalculate our estcpu.
658 lp->lwp_stat = LSRUN;
660 p->p_usched->recalculate(lp);
664 td->td_flags &= ~TDF_TSLEEP_DESCHEDULED;
668 * Make sure we haven't switched cpus while we were asleep. It's
669 * not supposed to happen. Cleanup our temporary flags.
671 KKASSERT(gd == td->td_gd);
674 * Cleanup the timeout. If the timeout has already occured thandle
675 * has already been stopped, otherwise stop thandle.
678 if (td->td_flags & TDF_TIMEOUT) {
679 td->td_flags &= ~TDF_TIMEOUT;
682 /* does not block when on same cpu */
683 callout_stop(&thandle);
688 * Make sure we have been removed from the sleepq. In most
689 * cases this will have been done for us already but it is
690 * possible for a scheduling IPI to be in-flight from a
691 * previous tsleep/tsleep_interlock() or due to a straight-out
692 * call to lwkt_schedule() (in the case of an interrupt thread),
693 * causing a spurious wakeup.
699 * Figure out the correct error return. If interrupted by a
700 * signal we want to return EINTR or ERESTART.
702 * If P_MAILBOX is set no automatic system call restart occurs
703 * and we return EINTR. P_MAILBOX is meant to be used as an
704 * interlock, the user must poll it prior to any system call
705 * that it wishes to interlock a mailbox signal against since
706 * the flag is cleared on *any* system call that sleeps.
708 * p->p_token is held in the p && catch case.
712 if (catch && error == 0) {
713 if ((p->p_flag & P_MAILBOX) && sig == 0) {
715 } else if (sig != 0 || (sig = CURSIG(lp))) {
716 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig))
723 lwkt_reltoken(&p->p_token);
724 lp->lwp_flag &= ~(LWP_BREAKTSLEEP | LWP_SINTR);
725 p->p_flag &= ~P_MAILBOX;
727 logtsleep1(tsleep_end);
733 * Interlocked spinlock sleep. An exclusively held spinlock must
734 * be passed to ssleep(). The function will atomically release the
735 * spinlock and tsleep on the ident, then reacquire the spinlock and
738 * This routine is fairly important along the critical path, so optimize it
742 ssleep(const volatile void *ident, struct spinlock *spin, int flags,
743 const char *wmesg, int timo)
745 globaldata_t gd = mycpu;
748 _tsleep_interlock(gd, ident, flags);
749 spin_unlock_quick(gd, spin);
750 error = tsleep(ident, flags | PINTERLOCKED, wmesg, timo);
751 spin_lock_quick(gd, spin);
757 lksleep(const volatile void *ident, struct lock *lock, int flags,
758 const char *wmesg, int timo)
760 globaldata_t gd = mycpu;
763 _tsleep_interlock(gd, ident, flags);
764 lockmgr(lock, LK_RELEASE);
765 error = tsleep(ident, flags | PINTERLOCKED, wmesg, timo);
766 lockmgr(lock, LK_EXCLUSIVE);
772 * Interlocked mutex sleep. An exclusively held mutex must be passed
773 * to mtxsleep(). The function will atomically release the mutex
774 * and tsleep on the ident, then reacquire the mutex and return.
777 mtxsleep(const volatile void *ident, struct mtx *mtx, int flags,
778 const char *wmesg, int timo)
780 globaldata_t gd = mycpu;
783 _tsleep_interlock(gd, ident, flags);
785 error = tsleep(ident, flags | PINTERLOCKED, wmesg, timo);
786 mtx_lock_ex_quick(mtx, wmesg);
792 * Interlocked serializer sleep. An exclusively held serializer must
793 * be passed to zsleep(). The function will atomically release
794 * the serializer and tsleep on the ident, then reacquire the serializer
798 zsleep(const volatile void *ident, struct lwkt_serialize *slz, int flags,
799 const char *wmesg, int timo)
801 globaldata_t gd = mycpu;
804 ASSERT_SERIALIZED(slz);
806 _tsleep_interlock(gd, ident, flags);
807 lwkt_serialize_exit(slz);
808 ret = tsleep(ident, flags | PINTERLOCKED, wmesg, timo);
809 lwkt_serialize_enter(slz);
815 * Directly block on the LWKT thread by descheduling it. This
816 * is much faster then tsleep(), but the only legal way to wake
817 * us up is to directly schedule the thread.
819 * Setting TDF_SINTR will cause new signals to directly schedule us.
821 * This routine must be called while in a critical section.
824 lwkt_sleep(const char *wmesg, int flags)
826 thread_t td = curthread;
829 if ((flags & PCATCH) == 0 || td->td_lwp == NULL) {
830 td->td_flags |= TDF_BLOCKED;
831 td->td_wmesg = wmesg;
832 lwkt_deschedule_self(td);
835 td->td_flags &= ~TDF_BLOCKED;
838 if ((sig = CURSIG(td->td_lwp)) != 0) {
839 if (SIGISMEMBER(td->td_proc->p_sigacts->ps_sigintr, sig))
845 td->td_flags |= TDF_BLOCKED | TDF_SINTR;
846 td->td_wmesg = wmesg;
847 lwkt_deschedule_self(td);
849 td->td_flags &= ~(TDF_BLOCKED | TDF_SINTR);
855 * Implement the timeout for tsleep.
857 * We set LWP_BREAKTSLEEP to indicate that an event has occured, but
858 * we only call setrunnable if the process is not stopped.
860 * This type of callout timeout is scheduled on the same cpu the process
861 * is sleeping on. Also, at the moment, the MP lock is held.
872 * Do this before we potentially block acquiring the token. Setting
873 * TDF_TIMEOUT tells tsleep that we have already stopped the callout.
876 td->td_flags |= TDF_TIMEOUT;
881 if ((lp = td->td_lwp) != NULL)
882 lwkt_gettoken(&lp->lwp_proc->p_token);
885 * Only do nominal wakeup processing if TDF_TIMEOUT and
886 * TDF_TSLEEP_DESCHEDULED are both still set. Otherwise
887 * we raced a wakeup or we began executed and raced due to
888 * blocking in the token above, and should do nothing.
890 if ((td->td_flags & (TDF_TIMEOUT | TDF_TSLEEP_DESCHEDULED)) ==
891 (TDF_TIMEOUT | TDF_TSLEEP_DESCHEDULED)) {
893 lp->lwp_flag |= LWP_BREAKTSLEEP;
894 if (lp->lwp_proc->p_stat != SSTOP)
901 lwkt_reltoken(&lp->lwp_proc->p_token);
907 * Make all processes sleeping on the specified identifier runnable.
908 * count may be zero or one only.
910 * The domain encodes the sleep/wakeup domain AND the first cpu to check
911 * (which is always the current cpu). As we iterate across cpus
913 * This call may run without the MP lock held. We can only manipulate thread
914 * state on the cpu owning the thread. We CANNOT manipulate process state
917 * _wakeup() can be passed to an IPI so we can't use (const volatile
921 _wakeup(void *ident, int domain)
933 logtsleep2(wakeup_beg, ident);
936 qp = &gd->gd_tsleep_hash[id];
938 for (td = TAILQ_FIRST(qp); td != NULL; td = ntd) {
939 ntd = TAILQ_NEXT(td, td_sleepq);
940 if (td->td_wchan == ident &&
941 td->td_wdomain == (domain & PDOMAIN_MASK)
943 KKASSERT(td->td_gd == gd);
945 if (td->td_flags & TDF_TSLEEP_DESCHEDULED) {
946 td->td_flags &= ~TDF_TSLEEP_DESCHEDULED;
948 if (domain & PWAKEUP_ONE)
957 * We finished checking the current cpu but there still may be
958 * more work to do. Either wakeup_one was requested and no matching
959 * thread was found, or a normal wakeup was requested and we have
960 * to continue checking cpus.
962 * It should be noted that this scheme is actually less expensive then
963 * the old scheme when waking up multiple threads, since we send
964 * only one IPI message per target candidate which may then schedule
965 * multiple threads. Before we could have wound up sending an IPI
966 * message for each thread on the target cpu (!= current cpu) that
967 * needed to be woken up.
969 * NOTE: Wakeups occuring on remote cpus are asynchronous. This
970 * should be ok since we are passing idents in the IPI rather then
973 if ((domain & PWAKEUP_MYCPU) == 0 &&
974 (mask = slpque_cpumasks[id] & gd->gd_other_cpus) != 0) {
975 lwkt_send_ipiq2_mask(mask, _wakeup, ident,
976 domain | PWAKEUP_MYCPU);
980 logtsleep1(wakeup_end);
985 * Wakeup all threads tsleep()ing on the specified ident, on all cpus
988 wakeup(const volatile void *ident)
990 _wakeup(__DEALL(ident), PWAKEUP_ENCODE(0, mycpu->gd_cpuid));
994 * Wakeup one thread tsleep()ing on the specified ident, on any cpu.
997 wakeup_one(const volatile void *ident)
999 /* XXX potentially round-robin the first responding cpu */
1000 _wakeup(__DEALL(ident), PWAKEUP_ENCODE(0, mycpu->gd_cpuid) | PWAKEUP_ONE);
1004 * Wakeup threads tsleep()ing on the specified ident on the current cpu
1008 wakeup_mycpu(const volatile void *ident)
1010 _wakeup(__DEALL(ident), PWAKEUP_MYCPU);
1014 * Wakeup one thread tsleep()ing on the specified ident on the current cpu
1018 wakeup_mycpu_one(const volatile void *ident)
1020 /* XXX potentially round-robin the first responding cpu */
1021 _wakeup(__DEALL(ident), PWAKEUP_MYCPU|PWAKEUP_ONE);
1025 * Wakeup all thread tsleep()ing on the specified ident on the specified cpu
1029 wakeup_oncpu(globaldata_t gd, const volatile void *ident)
1033 _wakeup(__DEALL(ident), PWAKEUP_MYCPU);
1035 lwkt_send_ipiq2(gd, _wakeup, __DEALL(ident), PWAKEUP_MYCPU);
1038 _wakeup(__DEALL(ident), PWAKEUP_MYCPU);
1043 * Wakeup one thread tsleep()ing on the specified ident on the specified cpu
1047 wakeup_oncpu_one(globaldata_t gd, const volatile void *ident)
1051 _wakeup(__DEALL(ident), PWAKEUP_MYCPU | PWAKEUP_ONE);
1053 lwkt_send_ipiq2(gd, _wakeup, __DEALL(ident),
1054 PWAKEUP_MYCPU | PWAKEUP_ONE);
1057 _wakeup(__DEALL(ident), PWAKEUP_MYCPU | PWAKEUP_ONE);
1062 * Wakeup all threads waiting on the specified ident that slept using
1063 * the specified domain, on all cpus.
1066 wakeup_domain(const volatile void *ident, int domain)
1068 _wakeup(__DEALL(ident), PWAKEUP_ENCODE(domain, mycpu->gd_cpuid));
1072 * Wakeup one thread waiting on the specified ident that slept using
1073 * the specified domain, on any cpu.
1076 wakeup_domain_one(const volatile void *ident, int domain)
1078 /* XXX potentially round-robin the first responding cpu */
1079 _wakeup(__DEALL(ident),
1080 PWAKEUP_ENCODE(domain, mycpu->gd_cpuid) | PWAKEUP_ONE);
1086 * Make a process runnable. lp->lwp_proc->p_token must be held on call.
1087 * This only has an effect if we are in SSLEEP. We only break out of the
1088 * tsleep if LWP_BREAKTSLEEP is set, otherwise we just fix-up the state.
1090 * NOTE: With p_token held we can only safely manipulate the process
1091 * structure and the lp's lwp_stat.
1094 setrunnable(struct lwp *lp)
1096 ASSERT_LWKT_TOKEN_HELD(&lp->lwp_proc->p_token);
1098 if (lp->lwp_stat == LSSTOP)
1099 lp->lwp_stat = LSSLEEP;
1100 if (lp->lwp_stat == LSSLEEP && (lp->lwp_flag & LWP_BREAKTSLEEP))
1101 _tsleep_wakeup(lp->lwp_thread);
1106 * The process is stopped due to some condition, usually because p_stat is
1107 * set to SSTOP, but also possibly due to being traced.
1109 * NOTE! If the caller sets SSTOP, the caller must also clear P_WAITED
1110 * because the parent may check the child's status before the child actually
1111 * gets to this routine.
1113 * This routine is called with the current lwp only, typically just
1114 * before returning to userland.
1116 * Setting LWP_BREAKTSLEEP before entering the tsleep will cause a passive
1117 * SIGCONT to break out of the tsleep.
1122 struct lwp *lp = curthread->td_lwp;
1123 struct proc *p = lp->lwp_proc;
1127 * If LWP_WSTOP is set, we were sleeping
1128 * while our process was stopped. At this point
1129 * we were already counted as stopped.
1131 if ((lp->lwp_flag & LWP_WSTOP) == 0) {
1133 * If we're the last thread to stop, signal
1137 lp->lwp_flag |= LWP_WSTOP;
1138 wakeup(&p->p_nstopped);
1139 if (p->p_nstopped == p->p_nthreads) {
1140 p->p_flag &= ~P_WAITED;
1142 if ((p->p_pptr->p_sigacts->ps_flag & PS_NOCLDSTOP) == 0)
1143 ksignal(p->p_pptr, SIGCHLD);
1146 while (p->p_stat == SSTOP) {
1147 lp->lwp_flag |= LWP_BREAKTSLEEP;
1148 lp->lwp_stat = LSSTOP;
1149 tsleep(p, 0, "stop", 0);
1152 lp->lwp_flag &= ~LWP_WSTOP;
1157 * Compute a tenex style load average of a quantity on
1158 * 1, 5 and 15 minute intervals.
1160 static int loadav_count_runnable(struct lwp *p, void *data);
1165 struct loadavg *avg;
1169 alllwp_scan(loadav_count_runnable, &nrun);
1171 for (i = 0; i < 3; i++) {
1172 avg->ldavg[i] = (cexp[i] * avg->ldavg[i] +
1173 nrun * FSCALE * (FSCALE - cexp[i])) >> FSHIFT;
1177 * Schedule the next update to occur after 5 seconds, but add a
1178 * random variation to avoid synchronisation with processes that
1179 * run at regular intervals.
1181 callout_reset(&loadav_callout, hz * 4 + (int)(krandom() % (hz * 2 + 1)),
1186 loadav_count_runnable(struct lwp *lp, void *data)
1191 switch (lp->lwp_stat) {
1193 if ((td = lp->lwp_thread) == NULL)
1195 if (td->td_flags & TDF_BLOCKED)
1207 sched_setup(void *dummy)
1209 callout_init_mp(&loadav_callout);
1210 callout_init_mp(&schedcpu_callout);
1212 /* Kick off timeout driven events by calling first time. */