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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>
66 #include <sys/mplock2.h>
68 #include <machine/cpu.h>
69 #include <machine/smp.h>
71 TAILQ_HEAD(tslpque, thread);
73 static void sched_setup (void *dummy);
74 SYSINIT(sched_setup, SI_SUB_KICK_SCHEDULER, SI_ORDER_FIRST, sched_setup, NULL)
79 int sched_quantum; /* Roundrobin scheduling quantum in ticks. */
81 int ncpus2, ncpus2_shift, ncpus2_mask;
82 int ncpus_fit, ncpus_fit_mask;
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(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)
210 FOREACH_LWP_IN_PROC(lp, p) {
211 if (lp->lwp_stat == LSSLEEP)
215 * Only recalculate processes that are active or have slept
216 * less then 2 seconds. The schedulers understand this.
218 if (lp->lwp_slptime <= 1) {
219 p->p_usched->recalculate(lp);
221 lp->lwp_pctcpu = (lp->lwp_pctcpu * ccpu) >> FSHIFT;
229 * Resource checks. XXX break out since ksignal/killproc can block,
230 * limiting us to one process killed per second. There is probably
234 schedcpu_resource(struct proc *p, void *data __unused)
240 if (p->p_stat == SIDL ||
241 p->p_stat == SZOMB ||
249 FOREACH_LWP_IN_PROC(lp, p) {
251 * We may have caught an lp in the middle of being
252 * created, lwp_thread can be NULL.
254 if (lp->lwp_thread) {
255 ttime += lp->lwp_thread->td_sticks;
256 ttime += lp->lwp_thread->td_uticks;
260 switch(plimit_testcpulimit(p->p_limit, ttime)) {
261 case PLIMIT_TESTCPU_KILL:
262 killproc(p, "exceeded maximum CPU limit");
264 case PLIMIT_TESTCPU_XCPU:
265 if ((p->p_flag & P_XCPU) == 0) {
278 * This is only used by ps. Generate a cpu percentage use over
279 * a period of one second.
284 updatepcpu(struct lwp *lp, int cpticks, int ttlticks)
289 acc = (cpticks << FSHIFT) / ttlticks;
290 if (ttlticks >= ESTCPUFREQ) {
291 lp->lwp_pctcpu = acc;
293 remticks = ESTCPUFREQ - ttlticks;
294 lp->lwp_pctcpu = (acc * ttlticks + lp->lwp_pctcpu * remticks) /
300 * tsleep/wakeup hash table parameters. Try to find the sweet spot for
301 * like addresses being slept on.
303 #define TABLESIZE 1024
304 #define LOOKUP(x) (((intptr_t)(x) >> 6) & (TABLESIZE - 1))
306 static cpumask_t slpque_cpumasks[TABLESIZE];
309 * General scheduler initialization. We force a reschedule 25 times
310 * a second by default. Note that cpu0 is initialized in early boot and
311 * cannot make any high level calls.
313 * Each cpu has its own sleep queue.
316 sleep_gdinit(globaldata_t gd)
318 static struct tslpque slpque_cpu0[TABLESIZE];
321 if (gd->gd_cpuid == 0) {
322 sched_quantum = (hz + 24) / 25;
323 hogticks = 2 * sched_quantum;
325 gd->gd_tsleep_hash = slpque_cpu0;
327 gd->gd_tsleep_hash = kmalloc(sizeof(slpque_cpu0),
328 M_TSLEEP, M_WAITOK | M_ZERO);
330 for (i = 0; i < TABLESIZE; ++i)
331 TAILQ_INIT(&gd->gd_tsleep_hash[i]);
335 * This is a dandy function that allows us to interlock tsleep/wakeup
336 * operations with unspecified upper level locks, such as lockmgr locks,
337 * simply by holding a critical section. The sequence is:
339 * (acquire upper level lock)
340 * tsleep_interlock(blah)
341 * (release upper level lock)
344 * Basically this functions queues us on the tsleep queue without actually
345 * descheduling us. When tsleep() is later called with PINTERLOCK it
346 * assumes the thread was already queued, otherwise it queues it there.
348 * Thus it is possible to receive the wakeup prior to going to sleep and
349 * the race conditions are covered.
352 _tsleep_interlock(globaldata_t gd, const volatile void *ident, int flags)
354 thread_t td = gd->gd_curthread;
357 crit_enter_quick(td);
358 if (td->td_flags & TDF_TSLEEPQ) {
359 id = LOOKUP(td->td_wchan);
360 TAILQ_REMOVE(&gd->gd_tsleep_hash[id], td, td_sleepq);
361 if (TAILQ_FIRST(&gd->gd_tsleep_hash[id]) == NULL)
362 atomic_clear_int(&slpque_cpumasks[id], gd->gd_cpumask);
364 td->td_flags |= TDF_TSLEEPQ;
367 TAILQ_INSERT_TAIL(&gd->gd_tsleep_hash[id], td, td_sleepq);
368 atomic_set_int(&slpque_cpumasks[id], gd->gd_cpumask);
369 td->td_wchan = ident;
370 td->td_wdomain = flags & PDOMAIN_MASK;
375 tsleep_interlock(const volatile void *ident, int flags)
377 _tsleep_interlock(mycpu, ident, flags);
381 * Remove thread from sleepq. Must be called with a critical section held.
384 _tsleep_remove(thread_t td)
386 globaldata_t gd = mycpu;
389 KKASSERT(td->td_gd == gd);
390 if (td->td_flags & TDF_TSLEEPQ) {
391 td->td_flags &= ~TDF_TSLEEPQ;
392 id = LOOKUP(td->td_wchan);
393 TAILQ_REMOVE(&gd->gd_tsleep_hash[id], td, td_sleepq);
394 if (TAILQ_FIRST(&gd->gd_tsleep_hash[id]) == NULL)
395 atomic_clear_int(&slpque_cpumasks[id], gd->gd_cpumask);
402 tsleep_remove(thread_t td)
408 * This function removes a thread from the tsleep queue and schedules
409 * it. This function may act asynchronously. The target thread may be
410 * sleeping on a different cpu.
412 * This function mus be called while in a critical section but if the
413 * target thread is sleeping on a different cpu we cannot safely probe
418 _tsleep_wakeup(struct thread *td)
421 globaldata_t gd = mycpu;
423 if (td->td_gd != gd) {
424 lwkt_send_ipiq(td->td_gd, (ipifunc1_t)tsleep_wakeup, td);
429 if (td->td_flags & TDF_TSLEEP_DESCHEDULED) {
430 td->td_flags &= ~TDF_TSLEEP_DESCHEDULED;
438 tsleep_wakeup(struct thread *td)
446 * General sleep call. Suspends the current process until a wakeup is
447 * performed on the specified identifier. The process will then be made
448 * runnable with the specified priority. Sleeps at most timo/hz seconds
449 * (0 means no timeout). If flags includes PCATCH flag, signals are checked
450 * before and after sleeping, else signals are not checked. Returns 0 if
451 * awakened, EWOULDBLOCK if the timeout expires. If PCATCH is set and a
452 * signal needs to be delivered, ERESTART is returned if the current system
453 * call should be restarted if possible, and EINTR is returned if the system
454 * call should be interrupted by the signal (return EINTR).
456 * Note that if we are a process, we release_curproc() before messing with
457 * the LWKT scheduler.
459 * During autoconfiguration or after a panic, a sleep will simply
460 * lower the priority briefly to allow interrupts, then return.
463 tsleep(const volatile void *ident, int flags, const char *wmesg, int timo)
465 struct thread *td = curthread;
466 struct lwp *lp = td->td_lwp;
467 struct proc *p = td->td_proc; /* may be NULL */
474 struct callout thandle;
477 * NOTE: removed KTRPOINT, it could cause races due to blocking
478 * even in stable. Just scrap it for now.
480 if (tsleep_now_works == 0 || panicstr) {
482 * After a panic, or before we actually have an operational
483 * softclock, just give interrupts a chance, then just return;
485 * don't run any other procs or panic below,
486 * in case this is the idle process and already asleep.
489 oldpri = td->td_pri & TDPRI_MASK;
490 lwkt_setpri_self(safepri);
492 lwkt_setpri_self(oldpri);
495 logtsleep2(tsleep_beg, ident);
497 KKASSERT(td != &gd->gd_idlethread); /* you must be kidding! */
500 * NOTE: all of this occurs on the current cpu, including any
501 * callout-based wakeups, so a critical section is a sufficient
504 * The entire sequence through to where we actually sleep must
505 * run without breaking the critical section.
507 catch = flags & PCATCH;
511 crit_enter_quick(td);
513 KASSERT(ident != NULL, ("tsleep: no ident"));
514 KASSERT(lp == NULL ||
515 lp->lwp_stat == LSRUN || /* Obvious */
516 lp->lwp_stat == LSSTOP, /* Set in tstop */
518 ident, wmesg, lp->lwp_stat));
521 * Setup for the current process (if this is a process).
526 * Early termination if PCATCH was set and a
527 * signal is pending, interlocked with the
530 * Early termination only occurs when tsleep() is
531 * entered while in a normal LSRUN state.
533 if ((sig = CURSIG(lp)) != 0)
537 * Early termination if PCATCH was set and a
538 * mailbox signal was possibly delivered prior to
539 * the system call even being made, in order to
540 * allow the user to interlock without having to
541 * make additional system calls.
543 if (p->p_flag & P_MAILBOX)
547 * Causes ksignal to wake us up when.
549 lp->lwp_flag |= LWP_SINTR;
554 * We interlock the sleep queue if the caller has not already done
557 if ((flags & PINTERLOCKED) == 0) {
559 _tsleep_interlock(gd, ident, flags);
564 * If no interlock was set we do an integrated interlock here.
565 * Make sure the current process has been untangled from
566 * the userland scheduler and initialize slptime to start
567 * counting. We must interlock the sleep queue before doing
568 * this to avoid wakeup/process-ipi races which can occur under
572 p->p_usched->release_curproc(lp);
577 * If the interlocked flag is set but our cpu bit in the slpqueue
578 * is no longer set, then a wakeup was processed inbetween the
579 * tsleep_interlock() (ours or the callers), and here. This can
580 * occur under numerous circumstances including when we release the
583 * Extreme loads can cause the sending of an IPI (e.g. wakeup()'s)
584 * to process incoming IPIs, thus draining incoming wakeups.
586 if ((td->td_flags & TDF_TSLEEPQ) == 0) {
587 logtsleep2(ilockfail, ident);
592 * scheduling is blocked while in a critical section. Coincide
593 * the descheduled-by-tsleep flag with the descheduling of the
596 lwkt_deschedule_self(td);
597 td->td_flags |= TDF_TSLEEP_DESCHEDULED;
598 td->td_wmesg = wmesg;
601 * Setup the timeout, if any
604 callout_init(&thandle);
605 callout_reset(&thandle, timo, endtsleep, td);
613 * Ok, we are sleeping. Place us in the SSLEEP state.
615 KKASSERT((lp->lwp_flag & LWP_ONRUNQ) == 0);
617 * tstop() sets LSSTOP, so don't fiddle with that.
619 if (lp->lwp_stat != LSSTOP)
620 lp->lwp_stat = LSSLEEP;
621 lp->lwp_ru.ru_nvcsw++;
625 * And when we are woken up, put us back in LSRUN. If we
626 * slept for over a second, recalculate our estcpu.
628 lp->lwp_stat = LSRUN;
630 p->p_usched->recalculate(lp);
637 * Make sure we haven't switched cpus while we were asleep. It's
638 * not supposed to happen. Cleanup our temporary flags.
640 KKASSERT(gd == td->td_gd);
643 * Cleanup the timeout.
646 if (td->td_flags & TDF_TIMEOUT) {
647 td->td_flags &= ~TDF_TIMEOUT;
650 callout_stop(&thandle);
655 * Make sure we have been removed from the sleepq. This should
656 * have been done for us already.
660 if (td->td_flags & TDF_TSLEEP_DESCHEDULED) {
661 td->td_flags &= ~TDF_TSLEEP_DESCHEDULED;
662 kprintf("td %p (%s) unexpectedly rescheduled\n",
667 * Figure out the correct error return. If interrupted by a
668 * signal we want to return EINTR or ERESTART.
670 * If P_MAILBOX is set no automatic system call restart occurs
671 * and we return EINTR. P_MAILBOX is meant to be used as an
672 * interlock, the user must poll it prior to any system call
673 * that it wishes to interlock a mailbox signal against since
674 * the flag is cleared on *any* system call that sleeps.
678 if (catch && error == 0) {
679 if ((p->p_flag & P_MAILBOX) && sig == 0) {
681 } else if (sig != 0 || (sig = CURSIG(lp))) {
682 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig))
688 lp->lwp_flag &= ~(LWP_BREAKTSLEEP | LWP_SINTR);
689 p->p_flag &= ~P_MAILBOX;
691 logtsleep1(tsleep_end);
697 * Interlocked spinlock sleep. An exclusively held spinlock must
698 * be passed to ssleep(). The function will atomically release the
699 * spinlock and tsleep on the ident, then reacquire the spinlock and
702 * This routine is fairly important along the critical path, so optimize it
706 ssleep(const volatile void *ident, struct spinlock *spin, int flags,
707 const char *wmesg, int timo)
709 globaldata_t gd = mycpu;
712 _tsleep_interlock(gd, ident, flags);
713 spin_unlock_wr_quick(gd, spin);
714 error = tsleep(ident, flags | PINTERLOCKED, wmesg, timo);
715 spin_lock_wr_quick(gd, spin);
721 lksleep(const volatile void *ident, struct lock *lock, int flags,
722 const char *wmesg, int timo)
724 globaldata_t gd = mycpu;
727 _tsleep_interlock(gd, ident, flags);
728 lockmgr(lock, LK_RELEASE);
729 error = tsleep(ident, flags | PINTERLOCKED, wmesg, timo);
730 lockmgr(lock, LK_EXCLUSIVE);
736 * Interlocked mutex sleep. An exclusively held mutex must be passed
737 * to mtxsleep(). The function will atomically release the mutex
738 * and tsleep on the ident, then reacquire the mutex and return.
741 mtxsleep(const volatile void *ident, struct mtx *mtx, int flags,
742 const char *wmesg, int timo)
744 globaldata_t gd = mycpu;
747 _tsleep_interlock(gd, ident, flags);
749 error = tsleep(ident, flags | PINTERLOCKED, wmesg, timo);
750 mtx_lock_ex_quick(mtx, wmesg);
756 * Interlocked serializer sleep. An exclusively held serializer must
757 * be passed to zsleep(). The function will atomically release
758 * the serializer and tsleep on the ident, then reacquire the serializer
762 zsleep(const volatile void *ident, struct lwkt_serialize *slz, int flags,
763 const char *wmesg, int timo)
765 globaldata_t gd = mycpu;
768 ASSERT_SERIALIZED(slz);
770 _tsleep_interlock(gd, ident, flags);
771 lwkt_serialize_exit(slz);
772 ret = tsleep(ident, flags | PINTERLOCKED, wmesg, timo);
773 lwkt_serialize_enter(slz);
779 * Directly block on the LWKT thread by descheduling it. This
780 * is much faster then tsleep(), but the only legal way to wake
781 * us up is to directly schedule the thread.
783 * Setting TDF_SINTR will cause new signals to directly schedule us.
785 * This routine must be called while in a critical section.
788 lwkt_sleep(const char *wmesg, int flags)
790 thread_t td = curthread;
793 if ((flags & PCATCH) == 0 || td->td_lwp == NULL) {
794 td->td_flags |= TDF_BLOCKED;
795 td->td_wmesg = wmesg;
796 lwkt_deschedule_self(td);
799 td->td_flags &= ~TDF_BLOCKED;
802 if ((sig = CURSIG(td->td_lwp)) != 0) {
803 if (SIGISMEMBER(td->td_proc->p_sigacts->ps_sigintr, sig))
809 td->td_flags |= TDF_BLOCKED | TDF_SINTR;
810 td->td_wmesg = wmesg;
811 lwkt_deschedule_self(td);
813 td->td_flags &= ~(TDF_BLOCKED | TDF_SINTR);
819 * Implement the timeout for tsleep.
821 * We set LWP_BREAKTSLEEP to indicate that an event has occured, but
822 * we only call setrunnable if the process is not stopped.
824 * This type of callout timeout is scheduled on the same cpu the process
825 * is sleeping on. Also, at the moment, the MP lock is held.
833 ASSERT_MP_LOCK_HELD(curthread);
837 * cpu interlock. Thread flags are only manipulated on
838 * the cpu owning the thread. proc flags are only manipulated
839 * by the older of the MP lock. We have both.
841 if (td->td_flags & TDF_TSLEEP_DESCHEDULED) {
842 td->td_flags |= TDF_TIMEOUT;
844 if ((lp = td->td_lwp) != NULL) {
845 lp->lwp_flag |= LWP_BREAKTSLEEP;
846 if (lp->lwp_proc->p_stat != SSTOP)
856 * Make all processes sleeping on the specified identifier runnable.
857 * count may be zero or one only.
859 * The domain encodes the sleep/wakeup domain AND the first cpu to check
860 * (which is always the current cpu). As we iterate across cpus
862 * This call may run without the MP lock held. We can only manipulate thread
863 * state on the cpu owning the thread. We CANNOT manipulate process state
866 * _wakeup() can be passed to an IPI so we can't use (const volatile
870 _wakeup(void *ident, int domain)
882 logtsleep2(wakeup_beg, ident);
885 qp = &gd->gd_tsleep_hash[id];
887 for (td = TAILQ_FIRST(qp); td != NULL; td = ntd) {
888 ntd = TAILQ_NEXT(td, td_sleepq);
889 if (td->td_wchan == ident &&
890 td->td_wdomain == (domain & PDOMAIN_MASK)
892 KKASSERT(td->td_gd == gd);
894 if (td->td_flags & TDF_TSLEEP_DESCHEDULED) {
895 td->td_flags &= ~TDF_TSLEEP_DESCHEDULED;
897 if (domain & PWAKEUP_ONE)
906 * We finished checking the current cpu but there still may be
907 * more work to do. Either wakeup_one was requested and no matching
908 * thread was found, or a normal wakeup was requested and we have
909 * to continue checking cpus.
911 * It should be noted that this scheme is actually less expensive then
912 * the old scheme when waking up multiple threads, since we send
913 * only one IPI message per target candidate which may then schedule
914 * multiple threads. Before we could have wound up sending an IPI
915 * message for each thread on the target cpu (!= current cpu) that
916 * needed to be woken up.
918 * NOTE: Wakeups occuring on remote cpus are asynchronous. This
919 * should be ok since we are passing idents in the IPI rather then
922 if ((domain & PWAKEUP_MYCPU) == 0 &&
923 (mask = slpque_cpumasks[id] & gd->gd_other_cpus) != 0) {
924 lwkt_send_ipiq2_mask(mask, _wakeup, ident,
925 domain | PWAKEUP_MYCPU);
929 logtsleep1(wakeup_end);
934 * Wakeup all threads tsleep()ing on the specified ident, on all cpus
937 wakeup(const volatile void *ident)
939 _wakeup(__DEALL(ident), PWAKEUP_ENCODE(0, mycpu->gd_cpuid));
943 * Wakeup one thread tsleep()ing on the specified ident, on any cpu.
946 wakeup_one(const volatile void *ident)
948 /* XXX potentially round-robin the first responding cpu */
949 _wakeup(__DEALL(ident), PWAKEUP_ENCODE(0, mycpu->gd_cpuid) | PWAKEUP_ONE);
953 * Wakeup threads tsleep()ing on the specified ident on the current cpu
957 wakeup_mycpu(const volatile void *ident)
959 _wakeup(__DEALL(ident), PWAKEUP_MYCPU);
963 * Wakeup one thread tsleep()ing on the specified ident on the current cpu
967 wakeup_mycpu_one(const volatile void *ident)
969 /* XXX potentially round-robin the first responding cpu */
970 _wakeup(__DEALL(ident), PWAKEUP_MYCPU|PWAKEUP_ONE);
974 * Wakeup all thread tsleep()ing on the specified ident on the specified cpu
978 wakeup_oncpu(globaldata_t gd, const volatile void *ident)
982 _wakeup(__DEALL(ident), PWAKEUP_MYCPU);
984 lwkt_send_ipiq2(gd, _wakeup, __DEALL(ident), PWAKEUP_MYCPU);
987 _wakeup(__DEALL(ident), PWAKEUP_MYCPU);
992 * Wakeup one thread tsleep()ing on the specified ident on the specified cpu
996 wakeup_oncpu_one(globaldata_t gd, const volatile void *ident)
1000 _wakeup(__DEALL(ident), PWAKEUP_MYCPU | PWAKEUP_ONE);
1002 lwkt_send_ipiq2(gd, _wakeup, __DEALL(ident),
1003 PWAKEUP_MYCPU | PWAKEUP_ONE);
1006 _wakeup(__DEALL(ident), PWAKEUP_MYCPU | PWAKEUP_ONE);
1011 * Wakeup all threads waiting on the specified ident that slept using
1012 * the specified domain, on all cpus.
1015 wakeup_domain(const volatile void *ident, int domain)
1017 _wakeup(__DEALL(ident), PWAKEUP_ENCODE(domain, mycpu->gd_cpuid));
1021 * Wakeup one thread waiting on the specified ident that slept using
1022 * the specified domain, on any cpu.
1025 wakeup_domain_one(const volatile void *ident, int domain)
1027 /* XXX potentially round-robin the first responding cpu */
1028 _wakeup(__DEALL(ident),
1029 PWAKEUP_ENCODE(domain, mycpu->gd_cpuid) | PWAKEUP_ONE);
1035 * Make a process runnable. The MP lock must be held on call. This only
1036 * has an effect if we are in SSLEEP. We only break out of the
1037 * tsleep if LWP_BREAKTSLEEP is set, otherwise we just fix-up the state.
1039 * NOTE: With the MP lock held we can only safely manipulate the process
1040 * structure. We cannot safely manipulate the thread structure.
1043 setrunnable(struct lwp *lp)
1046 ASSERT_MP_LOCK_HELD(curthread);
1047 if (lp->lwp_stat == LSSTOP)
1048 lp->lwp_stat = LSSLEEP;
1049 if (lp->lwp_stat == LSSLEEP && (lp->lwp_flag & LWP_BREAKTSLEEP))
1050 _tsleep_wakeup(lp->lwp_thread);
1055 * The process is stopped due to some condition, usually because p_stat is
1056 * set to SSTOP, but also possibly due to being traced.
1058 * NOTE! If the caller sets SSTOP, the caller must also clear P_WAITED
1059 * because the parent may check the child's status before the child actually
1060 * gets to this routine.
1062 * This routine is called with the current lwp only, typically just
1063 * before returning to userland.
1065 * Setting LWP_BREAKTSLEEP before entering the tsleep will cause a passive
1066 * SIGCONT to break out of the tsleep.
1071 struct lwp *lp = curthread->td_lwp;
1072 struct proc *p = lp->lwp_proc;
1076 * If LWP_WSTOP is set, we were sleeping
1077 * while our process was stopped. At this point
1078 * we were already counted as stopped.
1080 if ((lp->lwp_flag & LWP_WSTOP) == 0) {
1082 * If we're the last thread to stop, signal
1086 lp->lwp_flag |= LWP_WSTOP;
1087 wakeup(&p->p_nstopped);
1088 if (p->p_nstopped == p->p_nthreads) {
1089 p->p_flag &= ~P_WAITED;
1091 if ((p->p_pptr->p_sigacts->ps_flag & PS_NOCLDSTOP) == 0)
1092 ksignal(p->p_pptr, SIGCHLD);
1095 while (p->p_stat == SSTOP) {
1096 lp->lwp_flag |= LWP_BREAKTSLEEP;
1097 lp->lwp_stat = LSSTOP;
1098 tsleep(p, 0, "stop", 0);
1101 lp->lwp_flag &= ~LWP_WSTOP;
1106 * Yield / synchronous reschedule. This is a bit tricky because the trap
1107 * code might have set a lazy release on the switch function. Setting
1108 * P_PASSIVE_ACQ will ensure that the lazy release executes when we call
1109 * switch, and that we are given a greater chance of affinity with our
1112 * We call lwkt_setpri_self() to rotate our thread to the end of the lwkt
1113 * run queue. lwkt_switch() will also execute any assigned passive release
1114 * (which usually calls release_curproc()), allowing a same/higher priority
1115 * process to be designated as the current process.
1117 * While it is possible for a lower priority process to be designated,
1118 * it's call to lwkt_maybe_switch() in acquire_curproc() will likely
1119 * round-robin back to us and we will be able to re-acquire the current
1120 * process designation.
1127 struct thread *td = curthread;
1128 struct proc *p = td->td_proc;
1130 lwkt_setpri_self(td->td_pri & TDPRI_MASK);
1132 p->p_flag |= P_PASSIVE_ACQ;
1134 p->p_flag &= ~P_PASSIVE_ACQ;
1141 * Compute a tenex style load average of a quantity on
1142 * 1, 5 and 15 minute intervals.
1144 static int loadav_count_runnable(struct lwp *p, void *data);
1149 struct loadavg *avg;
1153 alllwp_scan(loadav_count_runnable, &nrun);
1155 for (i = 0; i < 3; i++) {
1156 avg->ldavg[i] = (cexp[i] * avg->ldavg[i] +
1157 nrun * FSCALE * (FSCALE - cexp[i])) >> FSHIFT;
1161 * Schedule the next update to occur after 5 seconds, but add a
1162 * random variation to avoid synchronisation with processes that
1163 * run at regular intervals.
1165 callout_reset(&loadav_callout, hz * 4 + (int)(krandom() % (hz * 2 + 1)),
1170 loadav_count_runnable(struct lwp *lp, void *data)
1175 switch (lp->lwp_stat) {
1177 if ((td = lp->lwp_thread) == NULL)
1179 if (td->td_flags & TDF_BLOCKED)
1191 sched_setup(void *dummy)
1193 callout_init(&loadav_callout);
1194 callout_init(&schedcpu_callout);
1196 /* Kick off timeout driven events by calling first time. */