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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/signal2.h>
51 #include <sys/resourcevar.h>
52 #include <sys/vmmeter.h>
53 #include <sys/sysctl.h>
57 #include <sys/ktrace.h>
59 #include <sys/xwait.h>
62 #include <sys/thread2.h>
63 #include <sys/spinlock2.h>
64 #include <sys/mutex2.h>
65 #include <sys/serialize.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;
81 int ncpus_fit, ncpus_fit_mask;
85 static struct callout loadav_callout;
86 static struct callout schedcpu_callout;
87 MALLOC_DEFINE(M_TSLEEP, "tslpque", "tsleep queues");
89 #if !defined(KTR_TSLEEP)
90 #define KTR_TSLEEP KTR_ALL
92 KTR_INFO_MASTER(tsleep);
93 KTR_INFO(KTR_TSLEEP, tsleep, tsleep_beg, 0, "tsleep enter %p", sizeof(void *));
94 KTR_INFO(KTR_TSLEEP, tsleep, tsleep_end, 1, "tsleep exit", 0);
95 KTR_INFO(KTR_TSLEEP, tsleep, wakeup_beg, 2, "wakeup enter %p", sizeof(void *));
96 KTR_INFO(KTR_TSLEEP, tsleep, wakeup_end, 3, "wakeup exit", 0);
97 KTR_INFO(KTR_TSLEEP, tsleep, ilockfail, 4, "interlock failed %p", sizeof(void *));
99 #define logtsleep1(name) KTR_LOG(tsleep_ ## name)
100 #define logtsleep2(name, val) KTR_LOG(tsleep_ ## name, val)
102 struct loadavg averunnable =
103 { {0, 0, 0}, FSCALE }; /* load average, of runnable procs */
105 * Constants for averages over 1, 5, and 15 minutes
106 * when sampling at 5 second intervals.
108 static fixpt_t cexp[3] = {
109 0.9200444146293232 * FSCALE, /* exp(-1/12) */
110 0.9834714538216174 * FSCALE, /* exp(-1/60) */
111 0.9944598480048967 * FSCALE, /* exp(-1/180) */
114 static void endtsleep (void *);
115 static void loadav (void *arg);
116 static void schedcpu (void *arg);
118 static void tsleep_wakeup(struct thread *td);
122 * Adjust the scheduler quantum. The quantum is specified in microseconds.
123 * Note that 'tick' is in microseconds per tick.
126 sysctl_kern_quantum(SYSCTL_HANDLER_ARGS)
130 new_val = sched_quantum * tick;
131 error = sysctl_handle_int(oidp, &new_val, 0, req);
132 if (error != 0 || req->newptr == NULL)
136 sched_quantum = new_val / tick;
137 hogticks = 2 * sched_quantum;
141 SYSCTL_PROC(_kern, OID_AUTO, quantum, CTLTYPE_INT|CTLFLAG_RW,
142 0, sizeof sched_quantum, sysctl_kern_quantum, "I", "");
145 * If `ccpu' is not equal to `exp(-1/20)' and you still want to use the
146 * faster/more-accurate formula, you'll have to estimate CCPU_SHIFT below
147 * and possibly adjust FSHIFT in "param.h" so that (FSHIFT >= CCPU_SHIFT).
149 * To estimate CCPU_SHIFT for exp(-1/20), the following formula was used:
150 * 1 - exp(-1/20) ~= 0.0487 ~= 0.0488 == 1 (fixed pt, *11* bits).
152 * If you don't want to bother with the faster/more-accurate formula, you
153 * can set CCPU_SHIFT to (FSHIFT + 1) which will use a slower/less-accurate
154 * (more general) method of calculating the %age of CPU used by a process.
156 * decay 95% of `lwp_pctcpu' in 60 seconds; see CCPU_SHIFT before changing
158 #define CCPU_SHIFT 11
160 static fixpt_t ccpu = 0.95122942450071400909 * FSCALE; /* exp(-1/20) */
161 SYSCTL_INT(_kern, OID_AUTO, ccpu, CTLFLAG_RD, &ccpu, 0, "");
164 * kernel uses `FSCALE', userland (SHOULD) use kern.fscale
166 int fscale __unused = FSCALE; /* exported to systat */
167 SYSCTL_INT(_kern, OID_AUTO, fscale, CTLFLAG_RD, 0, FSCALE, "");
170 * Recompute process priorities, once a second.
172 * Since the userland schedulers are typically event oriented, if the
173 * estcpu calculation at wakeup() time is not sufficient to make a
174 * process runnable relative to other processes in the system we have
175 * a 1-second recalc to help out.
177 * This code also allows us to store sysclock_t data in the process structure
178 * without fear of an overrun, since sysclock_t are guarenteed to hold
179 * several seconds worth of count.
181 * WARNING! callouts can preempt normal threads. However, they will not
182 * preempt a thread holding a spinlock so we *can* safely use spinlocks.
184 static int schedcpu_stats(struct proc *p, void *data __unused);
185 static int schedcpu_resource(struct proc *p, void *data __unused);
190 allproc_scan(schedcpu_stats, NULL);
191 allproc_scan(schedcpu_resource, NULL);
192 wakeup((caddr_t)&lbolt);
193 wakeup((caddr_t)&lbolt_syncer);
194 callout_reset(&schedcpu_callout, hz, schedcpu, NULL);
198 * General process statistics once a second
201 schedcpu_stats(struct proc *p, void *data __unused)
207 FOREACH_LWP_IN_PROC(lp, p) {
208 if (lp->lwp_stat == LSSLEEP)
212 * Only recalculate processes that are active or have slept
213 * less then 2 seconds. The schedulers understand this.
215 if (lp->lwp_slptime <= 1) {
216 p->p_usched->recalculate(lp);
218 lp->lwp_pctcpu = (lp->lwp_pctcpu * ccpu) >> FSHIFT;
226 * Resource checks. XXX break out since ksignal/killproc can block,
227 * limiting us to one process killed per second. There is probably
231 schedcpu_resource(struct proc *p, void *data __unused)
237 if (p->p_stat == SIDL ||
238 p->p_stat == SZOMB ||
246 FOREACH_LWP_IN_PROC(lp, p) {
248 * We may have caught an lp in the middle of being
249 * created, lwp_thread can be NULL.
251 if (lp->lwp_thread) {
252 ttime += lp->lwp_thread->td_sticks;
253 ttime += lp->lwp_thread->td_uticks;
257 switch(plimit_testcpulimit(p->p_limit, ttime)) {
258 case PLIMIT_TESTCPU_KILL:
259 killproc(p, "exceeded maximum CPU limit");
261 case PLIMIT_TESTCPU_XCPU:
262 if ((p->p_flag & P_XCPU) == 0) {
275 * This is only used by ps. Generate a cpu percentage use over
276 * a period of one second.
281 updatepcpu(struct lwp *lp, int cpticks, int ttlticks)
286 acc = (cpticks << FSHIFT) / ttlticks;
287 if (ttlticks >= ESTCPUFREQ) {
288 lp->lwp_pctcpu = acc;
290 remticks = ESTCPUFREQ - ttlticks;
291 lp->lwp_pctcpu = (acc * ttlticks + lp->lwp_pctcpu * remticks) /
297 * tsleep/wakeup hash table parameters. Try to find the sweet spot for
298 * like addresses being slept on.
300 #define TABLESIZE 1024
301 #define LOOKUP(x) (((intptr_t)(x) >> 6) & (TABLESIZE - 1))
303 static cpumask_t slpque_cpumasks[TABLESIZE];
306 * General scheduler initialization. We force a reschedule 25 times
307 * a second by default. Note that cpu0 is initialized in early boot and
308 * cannot make any high level calls.
310 * Each cpu has its own sleep queue.
313 sleep_gdinit(globaldata_t gd)
315 static struct tslpque slpque_cpu0[TABLESIZE];
318 if (gd->gd_cpuid == 0) {
319 sched_quantum = (hz + 24) / 25;
320 hogticks = 2 * sched_quantum;
322 gd->gd_tsleep_hash = slpque_cpu0;
324 gd->gd_tsleep_hash = kmalloc(sizeof(slpque_cpu0),
325 M_TSLEEP, M_WAITOK | M_ZERO);
327 for (i = 0; i < TABLESIZE; ++i)
328 TAILQ_INIT(&gd->gd_tsleep_hash[i]);
332 * This is a dandy function that allows us to interlock tsleep/wakeup
333 * operations with unspecified upper level locks, such as lockmgr locks,
334 * simply by holding a critical section. The sequence is:
336 * (acquire upper level lock)
337 * tsleep_interlock(blah)
338 * (release upper level lock)
341 * Basically this functions queues us on the tsleep queue without actually
342 * descheduling us. When tsleep() is later called with PINTERLOCK it
343 * assumes the thread was already queued, otherwise it queues it there.
345 * Thus it is possible to receive the wakeup prior to going to sleep and
346 * the race conditions are covered.
349 _tsleep_interlock(globaldata_t gd, void *ident, int flags)
351 thread_t td = gd->gd_curthread;
354 crit_enter_quick(td);
355 if (td->td_flags & TDF_TSLEEPQ) {
356 id = LOOKUP(td->td_wchan);
357 TAILQ_REMOVE(&gd->gd_tsleep_hash[id], td, td_sleepq);
358 if (TAILQ_FIRST(&gd->gd_tsleep_hash[id]) == NULL)
359 atomic_clear_int(&slpque_cpumasks[id], gd->gd_cpumask);
361 td->td_flags |= TDF_TSLEEPQ;
364 TAILQ_INSERT_TAIL(&gd->gd_tsleep_hash[id], td, td_sleepq);
365 atomic_set_int(&slpque_cpumasks[id], gd->gd_cpumask);
366 td->td_wchan = ident;
367 td->td_wdomain = flags & PDOMAIN_MASK;
372 tsleep_interlock(void *ident, int flags)
374 _tsleep_interlock(mycpu, ident, flags);
378 * Remove thread from sleepq. Must be called with a critical section held.
381 _tsleep_remove(thread_t td)
383 globaldata_t gd = mycpu;
386 KKASSERT(td->td_gd == gd);
387 if (td->td_flags & TDF_TSLEEPQ) {
388 td->td_flags &= ~TDF_TSLEEPQ;
389 id = LOOKUP(td->td_wchan);
390 TAILQ_REMOVE(&gd->gd_tsleep_hash[id], td, td_sleepq);
391 if (TAILQ_FIRST(&gd->gd_tsleep_hash[id]) == NULL)
392 atomic_clear_int(&slpque_cpumasks[id], gd->gd_cpumask);
399 tsleep_remove(thread_t td)
405 * This function removes a thread from the tsleep queue and schedules
406 * it. This function may act asynchronously. The target thread may be
407 * sleeping on a different cpu.
409 * This function mus be called while in a critical section but if the
410 * target thread is sleeping on a different cpu we cannot safely probe
415 _tsleep_wakeup(struct thread *td)
418 globaldata_t gd = mycpu;
420 if (td->td_gd != gd) {
421 lwkt_send_ipiq(td->td_gd, (ipifunc1_t)tsleep_wakeup, td);
426 if (td->td_flags & TDF_TSLEEP_DESCHEDULED) {
427 td->td_flags &= ~TDF_TSLEEP_DESCHEDULED;
435 tsleep_wakeup(struct thread *td)
443 * General sleep call. Suspends the current process until a wakeup is
444 * performed on the specified identifier. The process will then be made
445 * runnable with the specified priority. Sleeps at most timo/hz seconds
446 * (0 means no timeout). If flags includes PCATCH flag, signals are checked
447 * before and after sleeping, else signals are not checked. Returns 0 if
448 * awakened, EWOULDBLOCK if the timeout expires. If PCATCH is set and a
449 * signal needs to be delivered, ERESTART is returned if the current system
450 * call should be restarted if possible, and EINTR is returned if the system
451 * call should be interrupted by the signal (return EINTR).
453 * Note that if we are a process, we release_curproc() before messing with
454 * the LWKT scheduler.
456 * During autoconfiguration or after a panic, a sleep will simply
457 * lower the priority briefly to allow interrupts, then return.
460 tsleep(void *ident, int flags, const char *wmesg, int timo)
462 struct thread *td = curthread;
463 struct lwp *lp = td->td_lwp;
464 struct proc *p = td->td_proc; /* may be NULL */
471 struct callout thandle;
474 * NOTE: removed KTRPOINT, it could cause races due to blocking
475 * even in stable. Just scrap it for now.
477 if (tsleep_now_works == 0 || panicstr) {
479 * After a panic, or before we actually have an operational
480 * softclock, just give interrupts a chance, then just return;
482 * don't run any other procs or panic below,
483 * in case this is the idle process and already asleep.
486 oldpri = td->td_pri & TDPRI_MASK;
487 lwkt_setpri_self(safepri);
489 lwkt_setpri_self(oldpri);
492 logtsleep2(tsleep_beg, ident);
494 KKASSERT(td != &gd->gd_idlethread); /* you must be kidding! */
497 * NOTE: all of this occurs on the current cpu, including any
498 * callout-based wakeups, so a critical section is a sufficient
501 * The entire sequence through to where we actually sleep must
502 * run without breaking the critical section.
504 catch = flags & PCATCH;
508 crit_enter_quick(td);
510 KASSERT(ident != NULL, ("tsleep: no ident"));
511 KASSERT(lp == NULL ||
512 lp->lwp_stat == LSRUN || /* Obvious */
513 lp->lwp_stat == LSSTOP, /* Set in tstop */
515 ident, wmesg, lp->lwp_stat));
518 * Setup for the current process (if this is a process).
523 * Early termination if PCATCH was set and a
524 * signal is pending, interlocked with the
527 * Early termination only occurs when tsleep() is
528 * entered while in a normal LSRUN state.
530 if ((sig = CURSIG(lp)) != 0)
534 * Early termination if PCATCH was set and a
535 * mailbox signal was possibly delivered prior to
536 * the system call even being made, in order to
537 * allow the user to interlock without having to
538 * make additional system calls.
540 if (p->p_flag & P_MAILBOX)
544 * Causes ksignal to wake us up when.
546 lp->lwp_flag |= LWP_SINTR;
551 * We interlock the sleep queue if the caller has not already done
554 if ((flags & PINTERLOCKED) == 0) {
556 _tsleep_interlock(gd, ident, flags);
561 * If no interlock was set we do an integrated interlock here.
562 * Make sure the current process has been untangled from
563 * the userland scheduler and initialize slptime to start
564 * counting. We must interlock the sleep queue before doing
565 * this to avoid wakeup/process-ipi races which can occur under
569 p->p_usched->release_curproc(lp);
574 * If the interlocked flag is set but our cpu bit in the slpqueue
575 * is no longer set, then a wakeup was processed inbetween the
576 * tsleep_interlock() (ours or the callers), and here. This can
577 * occur under numerous circumstances including when we release the
580 * Extreme loads can cause the sending of an IPI (e.g. wakeup()'s)
581 * to process incoming IPIs, thus draining incoming wakeups.
583 if ((td->td_flags & TDF_TSLEEPQ) == 0) {
584 logtsleep2(ilockfail, ident);
589 * scheduling is blocked while in a critical section. Coincide
590 * the descheduled-by-tsleep flag with the descheduling of the
593 lwkt_deschedule_self(td);
594 td->td_flags |= TDF_TSLEEP_DESCHEDULED;
595 td->td_wmesg = wmesg;
598 * Setup the timeout, if any
601 callout_init(&thandle);
602 callout_reset(&thandle, timo, endtsleep, td);
610 * Ok, we are sleeping. Place us in the SSLEEP state.
612 KKASSERT((lp->lwp_flag & LWP_ONRUNQ) == 0);
614 * tstop() sets LSSTOP, so don't fiddle with that.
616 if (lp->lwp_stat != LSSTOP)
617 lp->lwp_stat = LSSLEEP;
618 lp->lwp_ru.ru_nvcsw++;
622 * And when we are woken up, put us back in LSRUN. If we
623 * slept for over a second, recalculate our estcpu.
625 lp->lwp_stat = LSRUN;
627 p->p_usched->recalculate(lp);
634 * Make sure we haven't switched cpus while we were asleep. It's
635 * not supposed to happen. Cleanup our temporary flags.
637 KKASSERT(gd == td->td_gd);
640 * Cleanup the timeout.
643 if (td->td_flags & TDF_TIMEOUT) {
644 td->td_flags &= ~TDF_TIMEOUT;
647 callout_stop(&thandle);
652 * Make sure we have been removed from the sleepq. This should
653 * have been done for us already.
657 if (td->td_flags & TDF_TSLEEP_DESCHEDULED) {
658 td->td_flags &= ~TDF_TSLEEP_DESCHEDULED;
659 kprintf("td %p (%s) unexpectedly rescheduled\n",
664 * Figure out the correct error return. If interrupted by a
665 * signal we want to return EINTR or ERESTART.
667 * If P_MAILBOX is set no automatic system call restart occurs
668 * and we return EINTR. P_MAILBOX is meant to be used as an
669 * interlock, the user must poll it prior to any system call
670 * that it wishes to interlock a mailbox signal against since
671 * the flag is cleared on *any* system call that sleeps.
675 if (catch && error == 0) {
676 if ((p->p_flag & P_MAILBOX) && sig == 0) {
678 } else if (sig != 0 || (sig = CURSIG(lp))) {
679 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig))
685 lp->lwp_flag &= ~(LWP_BREAKTSLEEP | LWP_SINTR);
686 p->p_flag &= ~P_MAILBOX;
688 logtsleep1(tsleep_end);
694 * Interlocked spinlock sleep. An exclusively held spinlock must
695 * be passed to ssleep(). The function will atomically release the
696 * spinlock and tsleep on the ident, then reacquire the spinlock and
699 * This routine is fairly important along the critical path, so optimize it
703 ssleep(void *ident, struct spinlock *spin, int flags,
704 const char *wmesg, int timo)
706 globaldata_t gd = mycpu;
709 _tsleep_interlock(gd, ident, flags);
710 spin_unlock_wr_quick(gd, spin);
711 error = tsleep(ident, flags | PINTERLOCKED, wmesg, timo);
712 spin_lock_wr_quick(gd, spin);
718 lksleep(void *ident, struct lock *lock, int flags,
719 const char *wmesg, int timo)
721 globaldata_t gd = mycpu;
724 _tsleep_interlock(gd, ident, flags);
725 lockmgr(lock, LK_RELEASE);
726 error = tsleep(ident, flags | PINTERLOCKED, wmesg, timo);
727 lockmgr(lock, LK_EXCLUSIVE);
733 * Interlocked mutex sleep. An exclusively held mutex must be passed
734 * to mtxsleep(). The function will atomically release the mutex
735 * and tsleep on the ident, then reacquire the mutex and return.
738 mtxsleep(void *ident, struct mtx *mtx, int flags,
739 const char *wmesg, int timo)
741 globaldata_t gd = mycpu;
744 _tsleep_interlock(gd, ident, flags);
746 error = tsleep(ident, flags | PINTERLOCKED, wmesg, timo);
747 mtx_lock_ex_quick(mtx, wmesg);
753 * Interlocked serializer sleep. An exclusively held serializer must
754 * be passed to zsleep(). The function will atomically release
755 * the serializer and tsleep on the ident, then reacquire the serializer
759 zsleep(void *ident, struct lwkt_serialize *slz, int flags,
760 const char *wmesg, int timo)
762 globaldata_t gd = mycpu;
765 ASSERT_SERIALIZED(slz);
767 _tsleep_interlock(gd, ident, flags);
768 lwkt_serialize_exit(slz);
769 ret = tsleep(ident, flags | PINTERLOCKED, wmesg, timo);
770 lwkt_serialize_enter(slz);
776 * Directly block on the LWKT thread by descheduling it. This
777 * is much faster then tsleep(), but the only legal way to wake
778 * us up is to directly schedule the thread.
780 * Setting TDF_SINTR will cause new signals to directly schedule us.
782 * This routine must be called while in a critical section.
785 lwkt_sleep(const char *wmesg, int flags)
787 thread_t td = curthread;
790 if ((flags & PCATCH) == 0 || td->td_lwp == NULL) {
791 td->td_flags |= TDF_BLOCKED;
792 td->td_wmesg = wmesg;
793 lwkt_deschedule_self(td);
796 td->td_flags &= ~TDF_BLOCKED;
799 if ((sig = CURSIG(td->td_lwp)) != 0) {
800 if (SIGISMEMBER(td->td_proc->p_sigacts->ps_sigintr, sig))
806 td->td_flags |= TDF_BLOCKED | TDF_SINTR;
807 td->td_wmesg = wmesg;
808 lwkt_deschedule_self(td);
810 td->td_flags &= ~(TDF_BLOCKED | TDF_SINTR);
816 * Implement the timeout for tsleep.
818 * We set LWP_BREAKTSLEEP to indicate that an event has occured, but
819 * we only call setrunnable if the process is not stopped.
821 * This type of callout timeout is scheduled on the same cpu the process
822 * is sleeping on. Also, at the moment, the MP lock is held.
830 ASSERT_MP_LOCK_HELD(curthread);
834 * cpu interlock. Thread flags are only manipulated on
835 * the cpu owning the thread. proc flags are only manipulated
836 * by the older of the MP lock. We have both.
838 if (td->td_flags & TDF_TSLEEP_DESCHEDULED) {
839 td->td_flags |= TDF_TIMEOUT;
841 if ((lp = td->td_lwp) != NULL) {
842 lp->lwp_flag |= LWP_BREAKTSLEEP;
843 if (lp->lwp_proc->p_stat != SSTOP)
853 * Make all processes sleeping on the specified identifier runnable.
854 * count may be zero or one only.
856 * The domain encodes the sleep/wakeup domain AND the first cpu to check
857 * (which is always the current cpu). As we iterate across cpus
859 * This call may run without the MP lock held. We can only manipulate thread
860 * state on the cpu owning the thread. We CANNOT manipulate process state
864 _wakeup(void *ident, int domain)
876 logtsleep2(wakeup_beg, ident);
879 qp = &gd->gd_tsleep_hash[id];
881 for (td = TAILQ_FIRST(qp); td != NULL; td = ntd) {
882 ntd = TAILQ_NEXT(td, td_sleepq);
883 if (td->td_wchan == ident &&
884 td->td_wdomain == (domain & PDOMAIN_MASK)
886 KKASSERT(td->td_gd == gd);
888 if (td->td_flags & TDF_TSLEEP_DESCHEDULED) {
889 td->td_flags &= ~TDF_TSLEEP_DESCHEDULED;
891 if (domain & PWAKEUP_ONE)
900 * We finished checking the current cpu but there still may be
901 * more work to do. Either wakeup_one was requested and no matching
902 * thread was found, or a normal wakeup was requested and we have
903 * to continue checking cpus.
905 * It should be noted that this scheme is actually less expensive then
906 * the old scheme when waking up multiple threads, since we send
907 * only one IPI message per target candidate which may then schedule
908 * multiple threads. Before we could have wound up sending an IPI
909 * message for each thread on the target cpu (!= current cpu) that
910 * needed to be woken up.
912 * NOTE: Wakeups occuring on remote cpus are asynchronous. This
913 * should be ok since we are passing idents in the IPI rather then
916 if ((domain & PWAKEUP_MYCPU) == 0 &&
917 (mask = slpque_cpumasks[id] & gd->gd_other_cpus) != 0) {
918 lwkt_send_ipiq2_mask(mask, _wakeup, ident,
919 domain | PWAKEUP_MYCPU);
923 logtsleep1(wakeup_end);
928 * Wakeup all threads tsleep()ing on the specified ident, on all cpus
933 _wakeup(ident, PWAKEUP_ENCODE(0, mycpu->gd_cpuid));
937 * Wakeup one thread tsleep()ing on the specified ident, on any cpu.
940 wakeup_one(void *ident)
942 /* XXX potentially round-robin the first responding cpu */
943 _wakeup(ident, PWAKEUP_ENCODE(0, mycpu->gd_cpuid) | PWAKEUP_ONE);
947 * Wakeup threads tsleep()ing on the specified ident on the current cpu
951 wakeup_mycpu(void *ident)
953 _wakeup(ident, PWAKEUP_MYCPU);
957 * Wakeup one thread tsleep()ing on the specified ident on the current cpu
961 wakeup_mycpu_one(void *ident)
963 /* XXX potentially round-robin the first responding cpu */
964 _wakeup(ident, PWAKEUP_MYCPU|PWAKEUP_ONE);
968 * Wakeup all thread tsleep()ing on the specified ident on the specified cpu
972 wakeup_oncpu(globaldata_t gd, void *ident)
976 _wakeup(ident, PWAKEUP_MYCPU);
978 lwkt_send_ipiq2(gd, _wakeup, ident, PWAKEUP_MYCPU);
981 _wakeup(ident, PWAKEUP_MYCPU);
986 * Wakeup one thread tsleep()ing on the specified ident on the specified cpu
990 wakeup_oncpu_one(globaldata_t gd, void *ident)
994 _wakeup(ident, PWAKEUP_MYCPU | PWAKEUP_ONE);
996 lwkt_send_ipiq2(gd, _wakeup, ident, PWAKEUP_MYCPU | PWAKEUP_ONE);
999 _wakeup(ident, PWAKEUP_MYCPU | PWAKEUP_ONE);
1004 * Wakeup all threads waiting on the specified ident that slept using
1005 * the specified domain, on all cpus.
1008 wakeup_domain(void *ident, int domain)
1010 _wakeup(ident, PWAKEUP_ENCODE(domain, mycpu->gd_cpuid));
1014 * Wakeup one thread waiting on the specified ident that slept using
1015 * the specified domain, on any cpu.
1018 wakeup_domain_one(void *ident, int domain)
1020 /* XXX potentially round-robin the first responding cpu */
1021 _wakeup(ident, PWAKEUP_ENCODE(domain, mycpu->gd_cpuid) | PWAKEUP_ONE);
1027 * Make a process runnable. The MP lock must be held on call. This only
1028 * has an effect if we are in SSLEEP. We only break out of the
1029 * tsleep if LWP_BREAKTSLEEP is set, otherwise we just fix-up the state.
1031 * NOTE: With the MP lock held we can only safely manipulate the process
1032 * structure. We cannot safely manipulate the thread structure.
1035 setrunnable(struct lwp *lp)
1038 ASSERT_MP_LOCK_HELD(curthread);
1039 if (lp->lwp_stat == LSSTOP)
1040 lp->lwp_stat = LSSLEEP;
1041 if (lp->lwp_stat == LSSLEEP && (lp->lwp_flag & LWP_BREAKTSLEEP))
1042 _tsleep_wakeup(lp->lwp_thread);
1047 * The process is stopped due to some condition, usually because p_stat is
1048 * set to SSTOP, but also possibly due to being traced.
1050 * NOTE! If the caller sets SSTOP, the caller must also clear P_WAITED
1051 * because the parent may check the child's status before the child actually
1052 * gets to this routine.
1054 * This routine is called with the current lwp only, typically just
1055 * before returning to userland.
1057 * Setting LWP_BREAKTSLEEP before entering the tsleep will cause a passive
1058 * SIGCONT to break out of the tsleep.
1063 struct lwp *lp = curthread->td_lwp;
1064 struct proc *p = lp->lwp_proc;
1068 * If LWP_WSTOP is set, we were sleeping
1069 * while our process was stopped. At this point
1070 * we were already counted as stopped.
1072 if ((lp->lwp_flag & LWP_WSTOP) == 0) {
1074 * If we're the last thread to stop, signal
1078 lp->lwp_flag |= LWP_WSTOP;
1079 wakeup(&p->p_nstopped);
1080 if (p->p_nstopped == p->p_nthreads) {
1081 p->p_flag &= ~P_WAITED;
1083 if ((p->p_pptr->p_sigacts->ps_flag & PS_NOCLDSTOP) == 0)
1084 ksignal(p->p_pptr, SIGCHLD);
1087 while (p->p_stat == SSTOP) {
1088 lp->lwp_flag |= LWP_BREAKTSLEEP;
1089 lp->lwp_stat = LSSTOP;
1090 tsleep(p, 0, "stop", 0);
1093 lp->lwp_flag &= ~LWP_WSTOP;
1098 * Yield / synchronous reschedule. This is a bit tricky because the trap
1099 * code might have set a lazy release on the switch function. Setting
1100 * P_PASSIVE_ACQ will ensure that the lazy release executes when we call
1101 * switch, and that we are given a greater chance of affinity with our
1104 * We call lwkt_setpri_self() to rotate our thread to the end of the lwkt
1105 * run queue. lwkt_switch() will also execute any assigned passive release
1106 * (which usually calls release_curproc()), allowing a same/higher priority
1107 * process to be designated as the current process.
1109 * While it is possible for a lower priority process to be designated,
1110 * it's call to lwkt_maybe_switch() in acquire_curproc() will likely
1111 * round-robin back to us and we will be able to re-acquire the current
1112 * process designation.
1119 struct thread *td = curthread;
1120 struct proc *p = td->td_proc;
1122 lwkt_setpri_self(td->td_pri & TDPRI_MASK);
1124 p->p_flag |= P_PASSIVE_ACQ;
1126 p->p_flag &= ~P_PASSIVE_ACQ;
1133 * Compute a tenex style load average of a quantity on
1134 * 1, 5 and 15 minute intervals.
1136 static int loadav_count_runnable(struct lwp *p, void *data);
1141 struct loadavg *avg;
1145 alllwp_scan(loadav_count_runnable, &nrun);
1147 for (i = 0; i < 3; i++) {
1148 avg->ldavg[i] = (cexp[i] * avg->ldavg[i] +
1149 nrun * FSCALE * (FSCALE - cexp[i])) >> FSHIFT;
1153 * Schedule the next update to occur after 5 seconds, but add a
1154 * random variation to avoid synchronisation with processes that
1155 * run at regular intervals.
1157 callout_reset(&loadav_callout, hz * 4 + (int)(krandom() % (hz * 2 + 1)),
1162 loadav_count_runnable(struct lwp *lp, void *data)
1167 switch (lp->lwp_stat) {
1169 if ((td = lp->lwp_thread) == NULL)
1171 if (td->td_flags & TDF_BLOCKED)
1183 sched_setup(void *dummy)
1185 callout_init(&loadav_callout);
1186 callout_init(&schedcpu_callout);
1188 /* Kick off timeout driven events by calling first time. */