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4 * (c) UNIX System Laboratories, Inc.
5 * All or some portions of this file are derived from material licensed
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34 * @(#)kern_synch.c 8.9 (Berkeley) 5/19/95
35 * $FreeBSD: src/sys/kern/kern_synch.c,v 1.87.2.6 2002/10/13 07:29:53 kbyanc Exp $
38 #include "opt_ktrace.h"
40 #include <sys/param.h>
41 #include <sys/systm.h>
43 #include <sys/kernel.h>
44 #include <sys/signalvar.h>
45 #include <sys/resourcevar.h>
46 #include <sys/vmmeter.h>
47 #include <sys/sysctl.h>
51 #include <sys/ktrace.h>
54 #include <sys/serialize.h>
56 #include <sys/signal2.h>
57 #include <sys/thread2.h>
58 #include <sys/spinlock2.h>
59 #include <sys/mutex2.h>
61 #include <machine/cpu.h>
62 #include <machine/smp.h>
64 TAILQ_HEAD(tslpque
, thread
);
66 static void sched_setup (void *dummy
);
67 SYSINIT(sched_setup
, SI_SUB_KICK_SCHEDULER
, SI_ORDER_FIRST
, sched_setup
, NULL
);
71 int sched_quantum
; /* Roundrobin scheduling quantum in ticks. */
73 int ncpus2
, ncpus2_shift
, ncpus2_mask
; /* note: mask not cpumask_t */
74 int ncpus_fit
, ncpus_fit_mask
; /* note: mask not cpumask_t */
77 int tsleep_crypto_dump
= 0;
79 static struct callout loadav_callout
;
80 static struct callout schedcpu_callout
;
81 MALLOC_DEFINE(M_TSLEEP
, "tslpque", "tsleep queues");
83 #define __DEALL(ident) __DEQUALIFY(void *, ident)
85 #if !defined(KTR_TSLEEP)
86 #define KTR_TSLEEP KTR_ALL
88 KTR_INFO_MASTER(tsleep
);
89 KTR_INFO(KTR_TSLEEP
, tsleep
, tsleep_beg
, 0, "tsleep enter %p", const volatile void *ident
);
90 KTR_INFO(KTR_TSLEEP
, tsleep
, tsleep_end
, 1, "tsleep exit");
91 KTR_INFO(KTR_TSLEEP
, tsleep
, wakeup_beg
, 2, "wakeup enter %p", const volatile void *ident
);
92 KTR_INFO(KTR_TSLEEP
, tsleep
, wakeup_end
, 3, "wakeup exit");
93 KTR_INFO(KTR_TSLEEP
, tsleep
, ilockfail
, 4, "interlock failed %p", const volatile void *ident
);
95 #define logtsleep1(name) KTR_LOG(tsleep_ ## name)
96 #define logtsleep2(name, val) KTR_LOG(tsleep_ ## name, val)
98 struct loadavg averunnable
=
99 { {0, 0, 0}, FSCALE
}; /* load average, of runnable procs */
101 * Constants for averages over 1, 5, and 15 minutes
102 * when sampling at 5 second intervals.
104 static fixpt_t cexp
[3] = {
105 0.9200444146293232 * FSCALE
, /* exp(-1/12) */
106 0.9834714538216174 * FSCALE
, /* exp(-1/60) */
107 0.9944598480048967 * FSCALE
, /* exp(-1/180) */
110 static void endtsleep (void *);
111 static void loadav (void *arg
);
112 static void schedcpu (void *arg
);
115 * Adjust the scheduler quantum. The quantum is specified in microseconds.
116 * Note that 'tick' is in microseconds per tick.
119 sysctl_kern_quantum(SYSCTL_HANDLER_ARGS
)
123 new_val
= sched_quantum
* ustick
;
124 error
= sysctl_handle_int(oidp
, &new_val
, 0, req
);
125 if (error
!= 0 || req
->newptr
== NULL
)
127 if (new_val
< ustick
)
129 sched_quantum
= new_val
/ ustick
;
133 SYSCTL_PROC(_kern
, OID_AUTO
, quantum
, CTLTYPE_INT
|CTLFLAG_RW
,
134 0, sizeof sched_quantum
, sysctl_kern_quantum
, "I", "");
136 static int pctcpu_decay
= 10;
137 SYSCTL_INT(_kern
, OID_AUTO
, pctcpu_decay
, CTLFLAG_RW
, &pctcpu_decay
, 0, "");
140 * kernel uses `FSCALE', userland (SHOULD) use kern.fscale
142 int fscale __unused
= FSCALE
; /* exported to systat */
143 SYSCTL_INT(_kern
, OID_AUTO
, fscale
, CTLFLAG_RD
, 0, FSCALE
, "");
146 * Recompute process priorities, once a second.
148 * Since the userland schedulers are typically event oriented, if the
149 * estcpu calculation at wakeup() time is not sufficient to make a
150 * process runnable relative to other processes in the system we have
151 * a 1-second recalc to help out.
153 * This code also allows us to store sysclock_t data in the process structure
154 * without fear of an overrun, since sysclock_t are guarenteed to hold
155 * several seconds worth of count.
157 * WARNING! callouts can preempt normal threads. However, they will not
158 * preempt a thread holding a spinlock so we *can* safely use spinlocks.
160 static int schedcpu_stats(struct proc
*p
, void *data __unused
);
161 static int schedcpu_resource(struct proc
*p
, void *data __unused
);
166 allproc_scan(schedcpu_stats
, NULL
);
167 allproc_scan(schedcpu_resource
, NULL
);
168 wakeup((caddr_t
)&lbolt
);
169 wakeup(lbolt_syncer
);
170 callout_reset(&schedcpu_callout
, hz
, schedcpu
, NULL
);
174 * General process statistics once a second
177 schedcpu_stats(struct proc
*p
, void *data __unused
)
182 * Threads may not be completely set up if process in SIDL state.
184 if (p
->p_stat
== SIDL
)
188 if (lwkt_trytoken(&p
->p_token
) == FALSE
) {
194 FOREACH_LWP_IN_PROC(lp
, p
) {
195 if (lp
->lwp_stat
== LSSLEEP
) {
197 if (lp
->lwp_slptime
== 1)
198 p
->p_usched
->uload_update(lp
);
202 * Only recalculate processes that are active or have slept
203 * less then 2 seconds. The schedulers understand this.
204 * Otherwise decay by 50% per second.
206 if (lp
->lwp_slptime
<= 1) {
207 p
->p_usched
->recalculate(lp
);
211 decay
= pctcpu_decay
;
217 lp
->lwp_pctcpu
= (lp
->lwp_pctcpu
* (decay
- 1)) / decay
;
220 lwkt_reltoken(&p
->p_token
);
227 * Resource checks. XXX break out since ksignal/killproc can block,
228 * limiting us to one process killed per second. There is probably
232 schedcpu_resource(struct proc
*p
, void *data __unused
)
237 if (p
->p_stat
== SIDL
)
241 if (lwkt_trytoken(&p
->p_token
) == FALSE
) {
246 if (p
->p_stat
== SZOMB
|| p
->p_limit
== NULL
) {
247 lwkt_reltoken(&p
->p_token
);
253 FOREACH_LWP_IN_PROC(lp
, p
) {
255 * We may have caught an lp in the middle of being
256 * created, lwp_thread can be NULL.
258 if (lp
->lwp_thread
) {
259 ttime
+= lp
->lwp_thread
->td_sticks
;
260 ttime
+= lp
->lwp_thread
->td_uticks
;
264 switch(plimit_testcpulimit(p
->p_limit
, ttime
)) {
265 case PLIMIT_TESTCPU_KILL
:
266 killproc(p
, "exceeded maximum CPU limit");
268 case PLIMIT_TESTCPU_XCPU
:
269 if ((p
->p_flags
& P_XCPU
) == 0) {
270 p
->p_flags
|= P_XCPU
;
277 lwkt_reltoken(&p
->p_token
);
284 * This is only used by ps. Generate a cpu percentage use over
285 * a period of one second.
288 updatepcpu(struct lwp
*lp
, int cpticks
, int ttlticks
)
293 acc
= (cpticks
<< FSHIFT
) / ttlticks
;
294 if (ttlticks
>= ESTCPUFREQ
) {
295 lp
->lwp_pctcpu
= acc
;
297 remticks
= ESTCPUFREQ
- ttlticks
;
298 lp
->lwp_pctcpu
= (acc
* ttlticks
+ lp
->lwp_pctcpu
* remticks
) /
304 * tsleep/wakeup hash table parameters. Try to find the sweet spot for
305 * like addresses being slept on.
307 #define TABLESIZE 4001
308 #define LOOKUP(x) (((u_int)(uintptr_t)(x)) % TABLESIZE)
310 static cpumask_t slpque_cpumasks
[TABLESIZE
];
313 * General scheduler initialization. We force a reschedule 25 times
314 * a second by default. Note that cpu0 is initialized in early boot and
315 * cannot make any high level calls.
317 * Each cpu has its own sleep queue.
320 sleep_gdinit(globaldata_t gd
)
322 static struct tslpque slpque_cpu0
[TABLESIZE
];
325 if (gd
->gd_cpuid
== 0) {
326 sched_quantum
= (hz
+ 24) / 25;
327 gd
->gd_tsleep_hash
= slpque_cpu0
;
329 gd
->gd_tsleep_hash
= kmalloc(sizeof(slpque_cpu0
),
330 M_TSLEEP
, M_WAITOK
| M_ZERO
);
332 for (i
= 0; i
< TABLESIZE
; ++i
)
333 TAILQ_INIT(&gd
->gd_tsleep_hash
[i
]);
337 * This is a dandy function that allows us to interlock tsleep/wakeup
338 * operations with unspecified upper level locks, such as lockmgr locks,
339 * simply by holding a critical section. The sequence is:
341 * (acquire upper level lock)
342 * tsleep_interlock(blah)
343 * (release upper level lock)
346 * Basically this functions queues us on the tsleep queue without actually
347 * descheduling us. When tsleep() is later called with PINTERLOCK it
348 * assumes the thread was already queued, otherwise it queues it there.
350 * Thus it is possible to receive the wakeup prior to going to sleep and
351 * the race conditions are covered.
354 _tsleep_interlock(globaldata_t gd
, const volatile void *ident
, int flags
)
356 thread_t td
= gd
->gd_curthread
;
359 crit_enter_quick(td
);
360 if (td
->td_flags
& TDF_TSLEEPQ
) {
361 id
= LOOKUP(td
->td_wchan
);
362 TAILQ_REMOVE(&gd
->gd_tsleep_hash
[id
], td
, td_sleepq
);
363 if (TAILQ_FIRST(&gd
->gd_tsleep_hash
[id
]) == NULL
) {
364 ATOMIC_CPUMASK_NANDBIT(slpque_cpumasks
[id
],
368 td
->td_flags
|= TDF_TSLEEPQ
;
371 TAILQ_INSERT_TAIL(&gd
->gd_tsleep_hash
[id
], td
, td_sleepq
);
372 ATOMIC_CPUMASK_ORBIT(slpque_cpumasks
[id
], gd
->gd_cpuid
);
373 td
->td_wchan
= ident
;
374 td
->td_wdomain
= flags
& PDOMAIN_MASK
;
379 tsleep_interlock(const volatile void *ident
, int flags
)
381 _tsleep_interlock(mycpu
, ident
, flags
);
385 * Remove thread from sleepq. Must be called with a critical section held.
386 * The thread must not be migrating.
389 _tsleep_remove(thread_t td
)
391 globaldata_t gd
= mycpu
;
394 KKASSERT(td
->td_gd
== gd
&& IN_CRITICAL_SECT(td
));
395 KKASSERT((td
->td_flags
& TDF_MIGRATING
) == 0);
396 if (td
->td_flags
& TDF_TSLEEPQ
) {
397 td
->td_flags
&= ~TDF_TSLEEPQ
;
398 id
= LOOKUP(td
->td_wchan
);
399 TAILQ_REMOVE(&gd
->gd_tsleep_hash
[id
], td
, td_sleepq
);
400 if (TAILQ_FIRST(&gd
->gd_tsleep_hash
[id
]) == NULL
) {
401 ATOMIC_CPUMASK_NANDBIT(slpque_cpumasks
[id
],
410 tsleep_remove(thread_t td
)
416 * General sleep call. Suspends the current process until a wakeup is
417 * performed on the specified identifier. The process will then be made
418 * runnable with the specified priority. Sleeps at most timo/hz seconds
419 * (0 means no timeout). If flags includes PCATCH flag, signals are checked
420 * before and after sleeping, else signals are not checked. Returns 0 if
421 * awakened, EWOULDBLOCK if the timeout expires. If PCATCH is set and a
422 * signal needs to be delivered, ERESTART is returned if the current system
423 * call should be restarted if possible, and EINTR is returned if the system
424 * call should be interrupted by the signal (return EINTR).
426 * Note that if we are a process, we release_curproc() before messing with
427 * the LWKT scheduler.
429 * During autoconfiguration or after a panic, a sleep will simply
430 * lower the priority briefly to allow interrupts, then return.
432 * WARNING! This code can't block (short of switching away), or bad things
433 * will happen. No getting tokens, no blocking locks, etc.
436 tsleep(const volatile void *ident
, int flags
, const char *wmesg
, int timo
)
438 struct thread
*td
= curthread
;
439 struct lwp
*lp
= td
->td_lwp
;
440 struct proc
*p
= td
->td_proc
; /* may be NULL */
446 struct callout thandle
;
449 * Currently a severe hack. Make sure any delayed wakeups
450 * are flushed before we sleep or we might deadlock on whatever
451 * event we are sleeping on.
453 if (td
->td_flags
& TDF_DELAYED_WAKEUP
)
454 wakeup_end_delayed();
457 * NOTE: removed KTRPOINT, it could cause races due to blocking
458 * even in stable. Just scrap it for now.
460 if (!tsleep_crypto_dump
&& (tsleep_now_works
== 0 || panicstr
)) {
462 * After a panic, or before we actually have an operational
463 * softclock, just give interrupts a chance, then just return;
465 * don't run any other procs or panic below,
466 * in case this is the idle process and already asleep.
470 lwkt_setpri_self(safepri
);
472 lwkt_setpri_self(oldpri
);
475 logtsleep2(tsleep_beg
, ident
);
477 KKASSERT(td
!= &gd
->gd_idlethread
); /* you must be kidding! */
478 td
->td_wakefromcpu
= -1; /* overwritten by _wakeup */
481 * NOTE: all of this occurs on the current cpu, including any
482 * callout-based wakeups, so a critical section is a sufficient
485 * The entire sequence through to where we actually sleep must
486 * run without breaking the critical section.
488 catch = flags
& PCATCH
;
492 crit_enter_quick(td
);
494 KASSERT(ident
!= NULL
, ("tsleep: no ident"));
495 KASSERT(lp
== NULL
||
496 lp
->lwp_stat
== LSRUN
|| /* Obvious */
497 lp
->lwp_stat
== LSSTOP
, /* Set in tstop */
499 ident
, wmesg
, lp
->lwp_stat
));
502 * We interlock the sleep queue if the caller has not already done
503 * it for us. This must be done before we potentially acquire any
504 * tokens or we can loose the wakeup.
506 if ((flags
& PINTERLOCKED
) == 0) {
507 _tsleep_interlock(gd
, ident
, flags
);
511 * Setup for the current process (if this is a process). We must
512 * interlock with lwp_token to avoid remote wakeup races via
516 lwkt_gettoken(&lp
->lwp_token
);
519 * If the umbrella process is in the SCORE state then
520 * make sure that the thread is flagged going into a
521 * normal sleep to allow the core dump to proceed, otherwise
522 * the coredump can end up waiting forever. If the normal
523 * sleep is woken up, the thread will enter a stopped state
524 * upon return to userland.
526 * We do not want to interrupt or cause a thread exist at
527 * this juncture because that will mess-up the state the
528 * coredump is trying to save.
530 if (p
->p_stat
== SCORE
&&
531 (lp
->lwp_mpflags
& LWP_MP_WSTOP
) == 0) {
532 atomic_set_int(&lp
->lwp_mpflags
, LWP_MP_WSTOP
);
541 * Early termination if PCATCH was set and a
542 * signal is pending, interlocked with the
545 * Early termination only occurs when tsleep() is
546 * entered while in a normal LSRUN state.
548 if ((sig
= CURSIG(lp
)) != 0)
552 * Causes ksignal to wake us up if a signal is
553 * received (interlocked with p->p_token).
555 lp
->lwp_flags
|= LWP_SINTR
;
562 * Make sure the current process has been untangled from
563 * the userland scheduler and initialize slptime to start
566 * NOTE: td->td_wakefromcpu is pre-set by the release function
567 * for the dfly scheduler, and then adjusted by _wakeup()
570 p
->p_usched
->release_curproc(lp
);
575 * If the interlocked flag is set but our cpu bit in the slpqueue
576 * is no longer set, then a wakeup was processed inbetween the
577 * tsleep_interlock() (ours or the callers), and here. This can
578 * occur under numerous circumstances including when we release the
581 * Extreme loads can cause the sending of an IPI (e.g. wakeup()'s)
582 * to process incoming IPIs, thus draining incoming wakeups.
584 if ((td
->td_flags
& TDF_TSLEEPQ
) == 0) {
585 logtsleep2(ilockfail
, ident
);
590 * scheduling is blocked while in a critical section. Coincide
591 * the descheduled-by-tsleep flag with the descheduling of the
594 * The timer callout is localized on our cpu and interlocked by
595 * our critical section.
597 lwkt_deschedule_self(td
);
598 td
->td_flags
|= TDF_TSLEEP_DESCHEDULED
;
599 td
->td_wmesg
= wmesg
;
602 * Setup the timeout, if any. The timeout is only operable while
603 * the thread is flagged descheduled.
605 KKASSERT((td
->td_flags
& TDF_TIMEOUT
) == 0);
607 callout_init_mp(&thandle
);
608 callout_reset(&thandle
, timo
, endtsleep
, td
);
616 * Ok, we are sleeping. Place us in the SSLEEP state.
618 KKASSERT((lp
->lwp_mpflags
& LWP_MP_ONRUNQ
) == 0);
621 * tstop() sets LSSTOP, so don't fiddle with that.
623 if (lp
->lwp_stat
!= LSSTOP
)
624 lp
->lwp_stat
= LSSLEEP
;
625 lp
->lwp_ru
.ru_nvcsw
++;
626 p
->p_usched
->uload_update(lp
);
630 * And when we are woken up, put us back in LSRUN. If we
631 * slept for over a second, recalculate our estcpu.
633 lp
->lwp_stat
= LSRUN
;
634 if (lp
->lwp_slptime
) {
635 p
->p_usched
->uload_update(lp
);
636 p
->p_usched
->recalculate(lp
);
644 * Make sure we haven't switched cpus while we were asleep. It's
645 * not supposed to happen. Cleanup our temporary flags.
647 KKASSERT(gd
== td
->td_gd
);
650 * Cleanup the timeout. If the timeout has already occured thandle
651 * has already been stopped, otherwise stop thandle. If the timeout
652 * is running (the callout thread must be blocked trying to get
653 * lwp_token) then wait for us to get scheduled.
656 while (td
->td_flags
& TDF_TIMEOUT_RUNNING
) {
657 /* else we won't get rescheduled! */
658 if (lp
->lwp_stat
!= LSSTOP
)
659 lp
->lwp_stat
= LSSLEEP
;
660 lwkt_deschedule_self(td
);
661 td
->td_wmesg
= "tsrace";
663 kprintf("td %p %s: timeout race\n", td
, td
->td_comm
);
665 if (td
->td_flags
& TDF_TIMEOUT
) {
666 td
->td_flags
&= ~TDF_TIMEOUT
;
669 /* does not block when on same cpu */
670 callout_stop(&thandle
);
673 td
->td_flags
&= ~TDF_TSLEEP_DESCHEDULED
;
676 * Make sure we have been removed from the sleepq. In most
677 * cases this will have been done for us already but it is
678 * possible for a scheduling IPI to be in-flight from a
679 * previous tsleep/tsleep_interlock() or due to a straight-out
680 * call to lwkt_schedule() (in the case of an interrupt thread),
681 * causing a spurious wakeup.
687 * Figure out the correct error return. If interrupted by a
688 * signal we want to return EINTR or ERESTART.
692 if (catch && error
== 0) {
693 if (sig
!= 0 || (sig
= CURSIG(lp
))) {
694 if (SIGISMEMBER(p
->p_sigacts
->ps_sigintr
, sig
))
700 lp
->lwp_flags
&= ~LWP_SINTR
;
701 lwkt_reltoken(&lp
->lwp_token
);
703 logtsleep1(tsleep_end
);
709 * Interlocked spinlock sleep. An exclusively held spinlock must
710 * be passed to ssleep(). The function will atomically release the
711 * spinlock and tsleep on the ident, then reacquire the spinlock and
714 * This routine is fairly important along the critical path, so optimize it
718 ssleep(const volatile void *ident
, struct spinlock
*spin
, int flags
,
719 const char *wmesg
, int timo
)
721 globaldata_t gd
= mycpu
;
724 _tsleep_interlock(gd
, ident
, flags
);
725 spin_unlock_quick(gd
, spin
);
726 error
= tsleep(ident
, flags
| PINTERLOCKED
, wmesg
, timo
);
727 _spin_lock_quick(gd
, spin
, wmesg
);
733 lksleep(const volatile void *ident
, struct lock
*lock
, int flags
,
734 const char *wmesg
, int timo
)
736 globaldata_t gd
= mycpu
;
739 _tsleep_interlock(gd
, ident
, flags
);
740 lockmgr(lock
, LK_RELEASE
);
741 error
= tsleep(ident
, flags
| PINTERLOCKED
, wmesg
, timo
);
742 lockmgr(lock
, LK_EXCLUSIVE
);
748 * Interlocked mutex sleep. An exclusively held mutex must be passed
749 * to mtxsleep(). The function will atomically release the mutex
750 * and tsleep on the ident, then reacquire the mutex and return.
753 mtxsleep(const volatile void *ident
, struct mtx
*mtx
, int flags
,
754 const char *wmesg
, int timo
)
756 globaldata_t gd
= mycpu
;
759 _tsleep_interlock(gd
, ident
, flags
);
761 error
= tsleep(ident
, flags
| PINTERLOCKED
, wmesg
, timo
);
762 mtx_lock_ex_quick(mtx
);
768 * Interlocked serializer sleep. An exclusively held serializer must
769 * be passed to zsleep(). The function will atomically release
770 * the serializer and tsleep on the ident, then reacquire the serializer
774 zsleep(const volatile void *ident
, struct lwkt_serialize
*slz
, int flags
,
775 const char *wmesg
, int timo
)
777 globaldata_t gd
= mycpu
;
780 ASSERT_SERIALIZED(slz
);
782 _tsleep_interlock(gd
, ident
, flags
);
783 lwkt_serialize_exit(slz
);
784 ret
= tsleep(ident
, flags
| PINTERLOCKED
, wmesg
, timo
);
785 lwkt_serialize_enter(slz
);
791 * Directly block on the LWKT thread by descheduling it. This
792 * is much faster then tsleep(), but the only legal way to wake
793 * us up is to directly schedule the thread.
795 * Setting TDF_SINTR will cause new signals to directly schedule us.
797 * This routine must be called while in a critical section.
800 lwkt_sleep(const char *wmesg
, int flags
)
802 thread_t td
= curthread
;
805 if ((flags
& PCATCH
) == 0 || td
->td_lwp
== NULL
) {
806 td
->td_flags
|= TDF_BLOCKED
;
807 td
->td_wmesg
= wmesg
;
808 lwkt_deschedule_self(td
);
811 td
->td_flags
&= ~TDF_BLOCKED
;
814 if ((sig
= CURSIG(td
->td_lwp
)) != 0) {
815 if (SIGISMEMBER(td
->td_proc
->p_sigacts
->ps_sigintr
, sig
))
821 td
->td_flags
|= TDF_BLOCKED
| TDF_SINTR
;
822 td
->td_wmesg
= wmesg
;
823 lwkt_deschedule_self(td
);
825 td
->td_flags
&= ~(TDF_BLOCKED
| TDF_SINTR
);
831 * Implement the timeout for tsleep.
833 * This type of callout timeout is scheduled on the same cpu the process
834 * is sleeping on. Also, at the moment, the MP lock is held.
843 * We are going to have to get the lwp_token, which means we might
844 * block. This can race a tsleep getting woken up by other means
845 * so set TDF_TIMEOUT_RUNNING to force the tsleep to wait for our
846 * processing to complete (sorry tsleep!).
848 * We can safely set td_flags because td MUST be on the same cpu
851 KKASSERT(td
->td_gd
== mycpu
);
853 td
->td_flags
|= TDF_TIMEOUT_RUNNING
| TDF_TIMEOUT
;
856 * This can block but TDF_TIMEOUT_RUNNING will prevent the thread
857 * from exiting the tsleep on us. The flag is interlocked by virtue
858 * of lp being on the same cpu as we are.
860 if ((lp
= td
->td_lwp
) != NULL
)
861 lwkt_gettoken(&lp
->lwp_token
);
863 KKASSERT(td
->td_flags
& TDF_TSLEEP_DESCHEDULED
);
867 * callout timer should never be set in tstop() because
868 * it passes a timeout of 0.
870 KKASSERT(lp
->lwp_stat
!= LSSTOP
);
872 lwkt_reltoken(&lp
->lwp_token
);
877 KKASSERT(td
->td_gd
== mycpu
);
878 td
->td_flags
&= ~TDF_TIMEOUT_RUNNING
;
883 * Make all processes sleeping on the specified identifier runnable.
884 * count may be zero or one only.
886 * The domain encodes the sleep/wakeup domain, flags, plus the originating
889 * This call may run without the MP lock held. We can only manipulate thread
890 * state on the cpu owning the thread. We CANNOT manipulate process state
893 * _wakeup() can be passed to an IPI so we can't use (const volatile
897 _wakeup(void *ident
, int domain
)
907 logtsleep2(wakeup_beg
, ident
);
910 qp
= &gd
->gd_tsleep_hash
[id
];
912 for (td
= TAILQ_FIRST(qp
); td
!= NULL
; td
= ntd
) {
913 ntd
= TAILQ_NEXT(td
, td_sleepq
);
914 if (td
->td_wchan
== ident
&&
915 td
->td_wdomain
== (domain
& PDOMAIN_MASK
)
917 KKASSERT(td
->td_gd
== gd
);
919 td
->td_wakefromcpu
= PWAKEUP_DECODE(domain
);
920 if (td
->td_flags
& TDF_TSLEEP_DESCHEDULED
) {
922 if (domain
& PWAKEUP_ONE
)
930 * We finished checking the current cpu but there still may be
931 * more work to do. Either wakeup_one was requested and no matching
932 * thread was found, or a normal wakeup was requested and we have
933 * to continue checking cpus.
935 * It should be noted that this scheme is actually less expensive then
936 * the old scheme when waking up multiple threads, since we send
937 * only one IPI message per target candidate which may then schedule
938 * multiple threads. Before we could have wound up sending an IPI
939 * message for each thread on the target cpu (!= current cpu) that
940 * needed to be woken up.
942 * NOTE: Wakeups occuring on remote cpus are asynchronous. This
943 * should be ok since we are passing idents in the IPI rather then
946 if ((domain
& PWAKEUP_MYCPU
) == 0) {
947 mask
= slpque_cpumasks
[id
];
948 CPUMASK_ANDMASK(mask
, gd
->gd_other_cpus
);
949 if (CPUMASK_TESTNZERO(mask
)) {
950 lwkt_send_ipiq2_mask(mask
, _wakeup
, ident
,
951 domain
| PWAKEUP_MYCPU
);
955 logtsleep1(wakeup_end
);
960 * Wakeup all threads tsleep()ing on the specified ident, on all cpus
963 wakeup(const volatile void *ident
)
965 globaldata_t gd
= mycpu
;
966 thread_t td
= gd
->gd_curthread
;
968 if (td
&& (td
->td_flags
& TDF_DELAYED_WAKEUP
)) {
970 * If we are in a delayed wakeup section, record up to two wakeups in
971 * a per-CPU queue and issue them when we block or exit the delayed
974 if (atomic_cmpset_ptr(&gd
->gd_delayed_wakeup
[0], NULL
, ident
))
976 if (atomic_cmpset_ptr(&gd
->gd_delayed_wakeup
[1], NULL
, ident
))
979 ident
= atomic_swap_ptr(__DEQUALIFY(volatile void **, &gd
->gd_delayed_wakeup
[1]),
981 ident
= atomic_swap_ptr(__DEQUALIFY(volatile void **, &gd
->gd_delayed_wakeup
[0]),
985 _wakeup(__DEALL(ident
), PWAKEUP_ENCODE(0, gd
->gd_cpuid
));
989 * Wakeup one thread tsleep()ing on the specified ident, on any cpu.
992 wakeup_one(const volatile void *ident
)
994 /* XXX potentially round-robin the first responding cpu */
995 _wakeup(__DEALL(ident
), PWAKEUP_ENCODE(0, mycpu
->gd_cpuid
) |
1000 * Wakeup threads tsleep()ing on the specified ident on the current cpu
1004 wakeup_mycpu(const volatile void *ident
)
1006 _wakeup(__DEALL(ident
), PWAKEUP_ENCODE(0, mycpu
->gd_cpuid
) |
1011 * Wakeup one thread tsleep()ing on the specified ident on the current cpu
1015 wakeup_mycpu_one(const volatile void *ident
)
1017 /* XXX potentially round-robin the first responding cpu */
1018 _wakeup(__DEALL(ident
), PWAKEUP_ENCODE(0, mycpu
->gd_cpuid
) |
1019 PWAKEUP_MYCPU
| PWAKEUP_ONE
);
1023 * Wakeup all thread tsleep()ing on the specified ident on the specified cpu
1027 wakeup_oncpu(globaldata_t gd
, const volatile void *ident
)
1029 globaldata_t mygd
= mycpu
;
1031 _wakeup(__DEALL(ident
), PWAKEUP_ENCODE(0, mygd
->gd_cpuid
) |
1034 lwkt_send_ipiq2(gd
, _wakeup
, __DEALL(ident
),
1035 PWAKEUP_ENCODE(0, mygd
->gd_cpuid
) |
1041 * Wakeup one thread tsleep()ing on the specified ident on the specified cpu
1045 wakeup_oncpu_one(globaldata_t gd
, const volatile void *ident
)
1047 globaldata_t mygd
= mycpu
;
1049 _wakeup(__DEALL(ident
), PWAKEUP_ENCODE(0, mygd
->gd_cpuid
) |
1050 PWAKEUP_MYCPU
| PWAKEUP_ONE
);
1052 lwkt_send_ipiq2(gd
, _wakeup
, __DEALL(ident
),
1053 PWAKEUP_ENCODE(0, mygd
->gd_cpuid
) |
1054 PWAKEUP_MYCPU
| PWAKEUP_ONE
);
1059 * Wakeup all threads waiting on the specified ident that slept using
1060 * the specified domain, on all cpus.
1063 wakeup_domain(const volatile void *ident
, int domain
)
1065 _wakeup(__DEALL(ident
), PWAKEUP_ENCODE(domain
, mycpu
->gd_cpuid
));
1069 * Wakeup one thread waiting on the specified ident that slept using
1070 * the specified domain, on any cpu.
1073 wakeup_domain_one(const volatile void *ident
, int domain
)
1075 /* XXX potentially round-robin the first responding cpu */
1076 _wakeup(__DEALL(ident
),
1077 PWAKEUP_ENCODE(domain
, mycpu
->gd_cpuid
) | PWAKEUP_ONE
);
1081 wakeup_start_delayed(void)
1083 globaldata_t gd
= mycpu
;
1086 gd
->gd_curthread
->td_flags
|= TDF_DELAYED_WAKEUP
;
1091 wakeup_end_delayed(void)
1093 globaldata_t gd
= mycpu
;
1095 if (gd
->gd_curthread
->td_flags
& TDF_DELAYED_WAKEUP
) {
1097 gd
->gd_curthread
->td_flags
&= ~TDF_DELAYED_WAKEUP
;
1098 if (gd
->gd_delayed_wakeup
[0] || gd
->gd_delayed_wakeup
[1]) {
1099 if (gd
->gd_delayed_wakeup
[0]) {
1100 wakeup(gd
->gd_delayed_wakeup
[0]);
1101 gd
->gd_delayed_wakeup
[0] = NULL
;
1103 if (gd
->gd_delayed_wakeup
[1]) {
1104 wakeup(gd
->gd_delayed_wakeup
[1]);
1105 gd
->gd_delayed_wakeup
[1] = NULL
;
1115 * Make a process runnable. lp->lwp_token must be held on call and this
1116 * function must be called from the cpu owning lp.
1118 * This only has an effect if we are in LSSTOP or LSSLEEP.
1121 setrunnable(struct lwp
*lp
)
1123 thread_t td
= lp
->lwp_thread
;
1125 ASSERT_LWKT_TOKEN_HELD(&lp
->lwp_token
);
1126 KKASSERT(td
->td_gd
== mycpu
);
1128 if (lp
->lwp_stat
== LSSTOP
)
1129 lp
->lwp_stat
= LSSLEEP
;
1130 if (lp
->lwp_stat
== LSSLEEP
) {
1133 } else if (td
->td_flags
& TDF_SINTR
) {
1140 * The process is stopped due to some condition, usually because p_stat is
1141 * set to SSTOP, but also possibly due to being traced.
1143 * Caller must hold p->p_token
1145 * NOTE! If the caller sets SSTOP, the caller must also clear P_WAITED
1146 * because the parent may check the child's status before the child actually
1147 * gets to this routine.
1149 * This routine is called with the current lwp only, typically just
1150 * before returning to userland if the process state is detected as
1151 * possibly being in a stopped state.
1156 struct lwp
*lp
= curthread
->td_lwp
;
1157 struct proc
*p
= lp
->lwp_proc
;
1160 lwkt_gettoken(&lp
->lwp_token
);
1164 * If LWP_MP_WSTOP is set, we were sleeping
1165 * while our process was stopped. At this point
1166 * we were already counted as stopped.
1168 if ((lp
->lwp_mpflags
& LWP_MP_WSTOP
) == 0) {
1170 * If we're the last thread to stop, signal
1174 atomic_set_int(&lp
->lwp_mpflags
, LWP_MP_WSTOP
);
1175 wakeup(&p
->p_nstopped
);
1176 if (p
->p_nstopped
== p
->p_nthreads
) {
1178 * Token required to interlock kern_wait()
1182 lwkt_gettoken(&q
->p_token
);
1183 p
->p_flags
&= ~P_WAITED
;
1185 if ((q
->p_sigacts
->ps_flag
& PS_NOCLDSTOP
) == 0)
1186 ksignal(q
, SIGCHLD
);
1187 lwkt_reltoken(&q
->p_token
);
1191 while (p
->p_stat
== SSTOP
|| p
->p_stat
== SCORE
) {
1192 lp
->lwp_stat
= LSSTOP
;
1193 tsleep(p
, 0, "stop", 0);
1196 atomic_clear_int(&lp
->lwp_mpflags
, LWP_MP_WSTOP
);
1198 lwkt_reltoken(&lp
->lwp_token
);
1202 * Compute a tenex style load average of a quantity on
1203 * 1, 5 and 15 minute intervals.
1205 static int loadav_count_runnable(struct lwp
*p
, void *data
);
1210 struct loadavg
*avg
;
1214 alllwp_scan(loadav_count_runnable
, &nrun
);
1216 for (i
= 0; i
< 3; i
++) {
1217 avg
->ldavg
[i
] = (cexp
[i
] * avg
->ldavg
[i
] +
1218 nrun
* FSCALE
* (FSCALE
- cexp
[i
])) >> FSHIFT
;
1222 * Schedule the next update to occur after 5 seconds, but add a
1223 * random variation to avoid synchronisation with processes that
1224 * run at regular intervals.
1226 callout_reset(&loadav_callout
, hz
* 4 + (int)(krandom() % (hz
* 2 + 1)),
1231 loadav_count_runnable(struct lwp
*lp
, void *data
)
1236 switch (lp
->lwp_stat
) {
1238 if ((td
= lp
->lwp_thread
) == NULL
)
1240 if (td
->td_flags
& TDF_BLOCKED
)
1253 sched_setup(void *dummy
)
1255 callout_init_mp(&loadav_callout
);
1256 callout_init_mp(&schedcpu_callout
);
1258 /* Kick off timeout driven events by calling first time. */