2 * Copyright (c) 1982, 1986, 1990, 1991, 1993
3 * The Regents of the University of California. All rights reserved.
4 * (c) UNIX System Laboratories, Inc.
5 * All or some portions of this file are derived from material licensed
6 * to the University of California by American Telephone and Telegraph
7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
8 * the permission of UNIX System Laboratories, Inc.
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11 * modification, are permitted provided that the following conditions
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
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31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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>
50 #include <sys/kcollect.h>
51 #include <sys/malloc.h>
53 #include <sys/ktrace.h>
56 #include <sys/serialize.h>
58 #include <sys/signal2.h>
59 #include <sys/thread2.h>
60 #include <sys/spinlock2.h>
61 #include <sys/mutex2.h>
63 #include <machine/cpu.h>
64 #include <machine/smp.h>
66 #include <vm/vm_extern.h>
69 TAILQ_HEAD(, thread
) queue
;
70 const volatile void *ident0
;
71 const volatile void *ident1
;
72 const volatile void *ident2
;
73 const volatile void *ident3
;
76 static void sched_setup (void *dummy
);
77 SYSINIT(sched_setup
, SI_SUB_KICK_SCHEDULER
, SI_ORDER_FIRST
, sched_setup
, NULL
);
78 static void sched_dyninit (void *dummy
);
79 SYSINIT(sched_dyninit
, SI_BOOT1_DYNALLOC
, SI_ORDER_FIRST
, sched_dyninit
, NULL
);
83 __read_mostly
int tsleep_crypto_dump
= 0;
84 __read_mostly
int ncpus
;
85 __read_mostly
int ncpus_fit
, ncpus_fit_mask
; /* note: mask not cpumask_t */
86 __read_mostly
int safepri
;
87 __read_mostly
int tsleep_now_works
;
89 MALLOC_DEFINE(M_TSLEEP
, "tslpque", "tsleep queues");
91 #define __DEALL(ident) __DEQUALIFY(void *, ident)
93 #if !defined(KTR_TSLEEP)
94 #define KTR_TSLEEP KTR_ALL
96 KTR_INFO_MASTER(tsleep
);
97 KTR_INFO(KTR_TSLEEP
, tsleep
, tsleep_beg
, 0, "tsleep enter %p", const volatile void *ident
);
98 KTR_INFO(KTR_TSLEEP
, tsleep
, tsleep_end
, 1, "tsleep exit");
99 KTR_INFO(KTR_TSLEEP
, tsleep
, wakeup_beg
, 2, "wakeup enter %p", const volatile void *ident
);
100 KTR_INFO(KTR_TSLEEP
, tsleep
, wakeup_end
, 3, "wakeup exit");
101 KTR_INFO(KTR_TSLEEP
, tsleep
, ilockfail
, 4, "interlock failed %p", const volatile void *ident
);
103 #define logtsleep1(name) KTR_LOG(tsleep_ ## name)
104 #define logtsleep2(name, val) KTR_LOG(tsleep_ ## name, val)
106 __exclusive_cache_line
107 struct loadavg averunnable
=
108 { {0, 0, 0}, FSCALE
}; /* load average, of runnable procs */
110 * Constants for averages over 1, 5, and 15 minutes
111 * when sampling at 5 second intervals.
114 static fixpt_t cexp
[3] = {
115 0.9200444146293232 * FSCALE
, /* exp(-1/12) */
116 0.9834714538216174 * FSCALE
, /* exp(-1/60) */
117 0.9944598480048967 * FSCALE
, /* exp(-1/180) */
120 static void endtsleep (void *);
121 static void loadav (void *arg
);
122 static void schedcpu (void *arg
);
124 __read_mostly
static int pctcpu_decay
= 10;
125 SYSCTL_INT(_kern
, OID_AUTO
, pctcpu_decay
, CTLFLAG_RW
,
126 &pctcpu_decay
, 0, "");
129 * kernel uses `FSCALE', userland (SHOULD) use kern.fscale
131 __read_mostly
int fscale __unused
= FSCALE
; /* exported to systat */
132 SYSCTL_INT(_kern
, OID_AUTO
, fscale
, CTLFLAG_RD
, 0, FSCALE
, "");
135 * Issue a wakeup() from userland (debugging)
138 sysctl_wakeup(SYSCTL_HANDLER_ARGS
)
143 if (req
->newptr
!= NULL
) {
144 if (priv_check(curthread
, PRIV_ROOT
))
146 error
= SYSCTL_IN(req
, &ident
, sizeof(ident
));
149 kprintf("issue wakeup %016jx\n", ident
);
150 wakeup((void *)(intptr_t)ident
);
152 if (req
->oldptr
!= NULL
) {
153 error
= SYSCTL_OUT(req
, &ident
, sizeof(ident
));
159 sysctl_wakeup_umtx(SYSCTL_HANDLER_ARGS
)
164 if (req
->newptr
!= NULL
) {
165 if (priv_check(curthread
, PRIV_ROOT
))
167 error
= SYSCTL_IN(req
, &ident
, sizeof(ident
));
170 kprintf("issue wakeup %016jx, PDOMAIN_UMTX\n", ident
);
171 wakeup_domain((void *)(intptr_t)ident
, PDOMAIN_UMTX
);
173 if (req
->oldptr
!= NULL
) {
174 error
= SYSCTL_OUT(req
, &ident
, sizeof(ident
));
179 SYSCTL_PROC(_debug
, OID_AUTO
, wakeup
, CTLTYPE_UQUAD
|CTLFLAG_RW
, 0, 0,
180 sysctl_wakeup
, "Q", "issue wakeup(addr)");
181 SYSCTL_PROC(_debug
, OID_AUTO
, wakeup_umtx
, CTLTYPE_UQUAD
|CTLFLAG_RW
, 0, 0,
182 sysctl_wakeup_umtx
, "Q", "issue wakeup(addr, PDOMAIN_UMTX)");
185 * Recompute process priorities, once a second.
187 * Since the userland schedulers are typically event oriented, if the
188 * estcpu calculation at wakeup() time is not sufficient to make a
189 * process runnable relative to other processes in the system we have
190 * a 1-second recalc to help out.
192 * This code also allows us to store sysclock_t data in the process structure
193 * without fear of an overrun, since sysclock_t are guarenteed to hold
194 * several seconds worth of count.
196 * WARNING! callouts can preempt normal threads. However, they will not
197 * preempt a thread holding a spinlock so we *can* safely use spinlocks.
199 static int schedcpu_stats(struct proc
*p
, void *data __unused
);
200 static int schedcpu_resource(struct proc
*p
, void *data __unused
);
205 allproc_scan(schedcpu_stats
, NULL
, 1);
206 allproc_scan(schedcpu_resource
, NULL
, 1);
207 if (mycpu
->gd_cpuid
== 0) {
208 wakeup((caddr_t
)&lbolt
);
209 wakeup(lbolt_syncer
);
211 callout_reset(&mycpu
->gd_schedcpu_callout
, hz
, schedcpu
, NULL
);
215 * General process statistics once a second
218 schedcpu_stats(struct proc
*p
, void *data __unused
)
223 * Threads may not be completely set up if process in SIDL state.
225 if (p
->p_stat
== SIDL
)
229 if (lwkt_trytoken(&p
->p_token
) == FALSE
) {
235 FOREACH_LWP_IN_PROC(lp
, p
) {
236 if (lp
->lwp_stat
== LSSLEEP
) {
238 if (lp
->lwp_slptime
== 1)
239 p
->p_usched
->uload_update(lp
);
243 * Only recalculate processes that are active or have slept
244 * less then 2 seconds. The schedulers understand this.
245 * Otherwise decay by 50% per second.
247 * NOTE: uload_update is called separately from kern_synch.c
248 * when slptime == 1, removing the thread's
251 if (lp
->lwp_slptime
<= 1) {
252 p
->p_usched
->recalculate(lp
);
256 decay
= pctcpu_decay
;
262 lp
->lwp_pctcpu
= (lp
->lwp_pctcpu
* (decay
- 1)) / decay
;
265 lwkt_reltoken(&p
->p_token
);
272 * Resource checks. XXX break out since ksignal/killproc can block,
273 * limiting us to one process killed per second. There is probably
277 schedcpu_resource(struct proc
*p
, void *data __unused
)
282 if (p
->p_stat
== SIDL
)
286 if (lwkt_trytoken(&p
->p_token
) == FALSE
) {
291 if (p
->p_stat
== SZOMB
|| p
->p_limit
== NULL
) {
292 lwkt_reltoken(&p
->p_token
);
298 FOREACH_LWP_IN_PROC(lp
, p
) {
300 * We may have caught an lp in the middle of being
301 * created, lwp_thread can be NULL.
303 if (lp
->lwp_thread
) {
304 ttime
+= lp
->lwp_thread
->td_sticks
;
305 ttime
+= lp
->lwp_thread
->td_uticks
;
309 switch(plimit_testcpulimit(p
, ttime
)) {
310 case PLIMIT_TESTCPU_KILL
:
311 killproc(p
, "exceeded maximum CPU limit");
313 case PLIMIT_TESTCPU_XCPU
:
314 if ((p
->p_flags
& P_XCPU
) == 0) {
315 p
->p_flags
|= P_XCPU
;
322 lwkt_reltoken(&p
->p_token
);
329 * This is only used by ps. Generate a cpu percentage use over
330 * a period of one second.
333 updatepcpu(struct lwp
*lp
, int cpticks
, int ttlticks
)
338 acc
= (cpticks
<< FSHIFT
) / ttlticks
;
339 if (ttlticks
>= ESTCPUFREQ
) {
340 lp
->lwp_pctcpu
= acc
;
342 remticks
= ESTCPUFREQ
- ttlticks
;
343 lp
->lwp_pctcpu
= (acc
* ttlticks
+ lp
->lwp_pctcpu
* remticks
) /
349 * Handy macros to calculate hash indices. LOOKUP() calculates the
350 * global cpumask hash index, TCHASHSHIFT() converts that into the
353 * By making the pcpu hash arrays smaller we save a significant amount
354 * of memory at very low cost. The real cost is in IPIs, which are handled
355 * by the much larger global cpumask hash table.
357 #define LOOKUP_PRIME 66555444443333333ULL
358 #define LOOKUP(x) ((((uintptr_t)(x) + ((uintptr_t)(x) >> 18)) ^ \
359 LOOKUP_PRIME) % slpque_tablesize)
360 #define TCHASHSHIFT(x) ((x) >> 4)
362 __read_mostly
static uint32_t slpque_tablesize
;
363 __read_mostly
static cpumask_t
*slpque_cpumasks
;
365 SYSCTL_UINT(_kern
, OID_AUTO
, slpque_tablesize
, CTLFLAG_RD
, &slpque_tablesize
,
369 * This is a dandy function that allows us to interlock tsleep/wakeup
370 * operations with unspecified upper level locks, such as lockmgr locks,
371 * simply by holding a critical section. The sequence is:
373 * (acquire upper level lock)
374 * tsleep_interlock(blah)
375 * (release upper level lock)
378 * Basically this functions queues us on the tsleep queue without actually
379 * descheduling us. When tsleep() is later called with PINTERLOCK it
380 * assumes the thread was already queued, otherwise it queues it there.
382 * Thus it is possible to receive the wakeup prior to going to sleep and
383 * the race conditions are covered.
386 _tsleep_interlock(globaldata_t gd
, const volatile void *ident
, int flags
)
388 thread_t td
= gd
->gd_curthread
;
394 kprintf("tsleep_interlock: NULL ident %s\n", td
->td_comm
);
398 crit_enter_quick(td
);
399 if (td
->td_flags
& TDF_TSLEEPQ
) {
401 * Shortcut if unchanged
403 if (td
->td_wchan
== ident
&&
404 td
->td_wdomain
== (flags
& PDOMAIN_MASK
)) {
410 * Remove current sleepq
412 cid
= LOOKUP(td
->td_wchan
);
413 gid
= TCHASHSHIFT(cid
);
414 qp
= &gd
->gd_tsleep_hash
[gid
];
415 TAILQ_REMOVE(&qp
->queue
, td
, td_sleepq
);
416 if (TAILQ_FIRST(&qp
->queue
) == NULL
) {
421 ATOMIC_CPUMASK_NANDBIT(slpque_cpumasks
[cid
],
425 td
->td_flags
|= TDF_TSLEEPQ
;
428 gid
= TCHASHSHIFT(cid
);
429 qp
= &gd
->gd_tsleep_hash
[gid
];
430 TAILQ_INSERT_TAIL(&qp
->queue
, td
, td_sleepq
);
431 if (qp
->ident0
!= ident
&& qp
->ident1
!= ident
&&
432 qp
->ident2
!= ident
&& qp
->ident3
!= ident
) {
433 if (qp
->ident0
== NULL
)
435 else if (qp
->ident1
== NULL
)
437 else if (qp
->ident2
== NULL
)
439 else if (qp
->ident3
== NULL
)
442 qp
->ident0
= (void *)(intptr_t)-1;
444 ATOMIC_CPUMASK_ORBIT(slpque_cpumasks
[cid
], gd
->gd_cpuid
);
445 td
->td_wchan
= ident
;
446 td
->td_wdomain
= flags
& PDOMAIN_MASK
;
451 tsleep_interlock(const volatile void *ident
, int flags
)
453 _tsleep_interlock(mycpu
, ident
, flags
);
457 * Remove thread from sleepq. Must be called with a critical section held.
458 * The thread must not be migrating.
461 _tsleep_remove(thread_t td
)
463 globaldata_t gd
= mycpu
;
468 KKASSERT(td
->td_gd
== gd
&& IN_CRITICAL_SECT(td
));
469 KKASSERT((td
->td_flags
& TDF_MIGRATING
) == 0);
470 if (td
->td_flags
& TDF_TSLEEPQ
) {
471 td
->td_flags
&= ~TDF_TSLEEPQ
;
472 cid
= LOOKUP(td
->td_wchan
);
473 gid
= TCHASHSHIFT(cid
);
474 qp
= &gd
->gd_tsleep_hash
[gid
];
475 TAILQ_REMOVE(&qp
->queue
, td
, td_sleepq
);
476 if (TAILQ_FIRST(&qp
->queue
) == NULL
) {
477 ATOMIC_CPUMASK_NANDBIT(slpque_cpumasks
[cid
],
486 tsleep_remove(thread_t td
)
492 * General sleep call. Suspends the current process until a wakeup is
493 * performed on the specified identifier. The process will then be made
494 * runnable with the specified priority. Sleeps at most timo/hz seconds
495 * (0 means no timeout). If flags includes PCATCH flag, signals are checked
496 * before and after sleeping, else signals are not checked. Returns 0 if
497 * awakened, EWOULDBLOCK if the timeout expires. If PCATCH is set and a
498 * signal needs to be delivered, ERESTART is returned if the current system
499 * call should be restarted if possible, and EINTR is returned if the system
500 * call should be interrupted by the signal (return EINTR).
502 * Note that if we are a process, we release_curproc() before messing with
503 * the LWKT scheduler.
505 * During autoconfiguration or after a panic, a sleep will simply
506 * lower the priority briefly to allow interrupts, then return.
508 * WARNING! This code can't block (short of switching away), or bad things
509 * will happen. No getting tokens, no blocking locks, etc.
512 tsleep(const volatile void *ident
, int flags
, const char *wmesg
, int timo
)
514 struct thread
*td
= curthread
;
515 struct lwp
*lp
= td
->td_lwp
;
516 struct proc
*p
= td
->td_proc
; /* may be NULL */
522 struct callout thandle
;
525 * Currently a severe hack. Make sure any delayed wakeups
526 * are flushed before we sleep or we might deadlock on whatever
527 * event we are sleeping on.
529 if (td
->td_flags
& TDF_DELAYED_WAKEUP
)
530 wakeup_end_delayed();
533 * NOTE: removed KTRPOINT, it could cause races due to blocking
534 * even in stable. Just scrap it for now.
536 if (!tsleep_crypto_dump
&& (tsleep_now_works
== 0 || panicstr
)) {
538 * After a panic, or before we actually have an operational
539 * softclock, just give interrupts a chance, then just return;
541 * don't run any other procs or panic below,
542 * in case this is the idle process and already asleep.
546 lwkt_setpri_self(safepri
);
548 lwkt_setpri_self(oldpri
);
551 logtsleep2(tsleep_beg
, ident
);
553 KKASSERT(td
!= &gd
->gd_idlethread
); /* you must be kidding! */
556 * NOTE: all of this occurs on the current cpu, including any
557 * callout-based wakeups, so a critical section is a sufficient
560 * The entire sequence through to where we actually sleep must
561 * run without breaking the critical section.
563 catch = flags
& PCATCH
;
567 crit_enter_quick(td
);
569 KASSERT(ident
!= NULL
, ("tsleep: no ident"));
570 KASSERT(lp
== NULL
||
571 lp
->lwp_stat
== LSRUN
|| /* Obvious */
572 lp
->lwp_stat
== LSSTOP
, /* Set in tstop */
574 ident
, wmesg
, lp
->lwp_stat
));
577 * We interlock the sleep queue if the caller has not already done
578 * it for us. This must be done before we potentially acquire any
579 * tokens or we can loose the wakeup.
581 if ((flags
& PINTERLOCKED
) == 0) {
582 _tsleep_interlock(gd
, ident
, flags
);
586 * Setup for the current process (if this is a process). We must
587 * interlock with lwp_token to avoid remote wakeup races via
591 lwkt_gettoken(&lp
->lwp_token
);
594 * If the umbrella process is in the SCORE state then
595 * make sure that the thread is flagged going into a
596 * normal sleep to allow the core dump to proceed, otherwise
597 * the coredump can end up waiting forever. If the normal
598 * sleep is woken up, the thread will enter a stopped state
599 * upon return to userland.
601 * We do not want to interrupt or cause a thread exist at
602 * this juncture because that will mess-up the state the
603 * coredump is trying to save.
605 if (p
->p_stat
== SCORE
) {
606 lwkt_gettoken(&p
->p_token
);
607 if ((lp
->lwp_mpflags
& LWP_MP_WSTOP
) == 0) {
608 atomic_set_int(&lp
->lwp_mpflags
, LWP_MP_WSTOP
);
611 lwkt_reltoken(&p
->p_token
);
619 * Early termination if PCATCH was set and a
620 * signal is pending, interlocked with the
623 * Early termination only occurs when tsleep() is
624 * entered while in a normal LSRUN state.
626 if ((sig
= CURSIG(lp
)) != 0)
630 * Causes ksignal to wake us up if a signal is
631 * received (interlocked with lp->lwp_token).
633 lp
->lwp_flags
|= LWP_SINTR
;
640 * Make sure the current process has been untangled from
641 * the userland scheduler and initialize slptime to start
644 * NOTE: td->td_wakefromcpu is pre-set by the release function
645 * for the dfly scheduler, and then adjusted by _wakeup()
648 p
->p_usched
->release_curproc(lp
);
653 * For PINTERLOCKED operation, TDF_TSLEEPQ might not be set if
654 * a wakeup() was processed before the thread could go to sleep.
656 * If TDF_TSLEEPQ is set, make sure the ident matches the recorded
657 * ident. If it does not then the thread slept inbetween the
658 * caller's initial tsleep_interlock() call and the caller's tsleep()
661 * Extreme loads can cause the sending of an IPI (e.g. wakeup()'s)
662 * to process incoming IPIs, thus draining incoming wakeups.
664 if ((td
->td_flags
& TDF_TSLEEPQ
) == 0) {
665 logtsleep2(ilockfail
, ident
);
667 } else if (td
->td_wchan
!= ident
||
668 td
->td_wdomain
!= (flags
& PDOMAIN_MASK
)) {
669 logtsleep2(ilockfail
, ident
);
674 * scheduling is blocked while in a critical section. Coincide
675 * the descheduled-by-tsleep flag with the descheduling of the
678 * The timer callout is localized on our cpu and interlocked by
679 * our critical section.
681 lwkt_deschedule_self(td
);
682 td
->td_flags
|= TDF_TSLEEP_DESCHEDULED
;
683 td
->td_wmesg
= wmesg
;
686 * Setup the timeout, if any. The timeout is only operable while
687 * the thread is flagged descheduled.
689 KKASSERT((td
->td_flags
& TDF_TIMEOUT
) == 0);
691 callout_init_mp(&thandle
);
692 callout_reset(&thandle
, timo
, endtsleep
, td
);
700 * Ok, we are sleeping. Place us in the SSLEEP state.
702 KKASSERT((lp
->lwp_mpflags
& LWP_MP_ONRUNQ
) == 0);
705 * tstop() sets LSSTOP, so don't fiddle with that.
707 if (lp
->lwp_stat
!= LSSTOP
)
708 lp
->lwp_stat
= LSSLEEP
;
709 lp
->lwp_ru
.ru_nvcsw
++;
710 p
->p_usched
->uload_update(lp
);
714 * And when we are woken up, put us back in LSRUN. If we
715 * slept for over a second, recalculate our estcpu.
717 lp
->lwp_stat
= LSRUN
;
718 if (lp
->lwp_slptime
) {
719 p
->p_usched
->uload_update(lp
);
720 p
->p_usched
->recalculate(lp
);
728 * Make sure we haven't switched cpus while we were asleep. It's
729 * not supposed to happen. Cleanup our temporary flags.
731 KKASSERT(gd
== td
->td_gd
);
734 * Cleanup the timeout. If the timeout has already occured thandle
735 * has already been stopped, otherwise stop thandle. If the timeout
736 * is running (the callout thread must be blocked trying to get
737 * lwp_token) then wait for us to get scheduled.
740 while (td
->td_flags
& TDF_TIMEOUT_RUNNING
) {
741 /* else we won't get rescheduled! */
742 if (lp
->lwp_stat
!= LSSTOP
)
743 lp
->lwp_stat
= LSSLEEP
;
744 lwkt_deschedule_self(td
);
745 td
->td_wmesg
= "tsrace";
747 kprintf("td %p %s: timeout race\n", td
, td
->td_comm
);
749 if (td
->td_flags
& TDF_TIMEOUT
) {
750 td
->td_flags
&= ~TDF_TIMEOUT
;
753 /* does not block when on same cpu */
754 callout_cancel(&thandle
);
757 td
->td_flags
&= ~TDF_TSLEEP_DESCHEDULED
;
760 * Make sure we have been removed from the sleepq. In most
761 * cases this will have been done for us already but it is
762 * possible for a scheduling IPI to be in-flight from a
763 * previous tsleep/tsleep_interlock() or due to a straight-out
764 * call to lwkt_schedule() (in the case of an interrupt thread),
765 * causing a spurious wakeup.
771 * Figure out the correct error return. If interrupted by a
772 * signal we want to return EINTR or ERESTART.
776 if (catch && error
== 0) {
777 if (sig
!= 0 || (sig
= CURSIG(lp
))) {
778 if (SIGISMEMBER(p
->p_sigacts
->ps_sigintr
, sig
))
785 lp
->lwp_flags
&= ~LWP_SINTR
;
788 * Unconditionally set us to LSRUN on resume. lwp_stat could
789 * be in a weird state due to the goto resume, particularly
790 * when tsleep() is called from tstop().
792 lp
->lwp_stat
= LSRUN
;
793 lwkt_reltoken(&lp
->lwp_token
);
795 logtsleep1(tsleep_end
);
802 * Interlocked spinlock sleep. An exclusively held spinlock must
803 * be passed to ssleep(). The function will atomically release the
804 * spinlock and tsleep on the ident, then reacquire the spinlock and
807 * This routine is fairly important along the critical path, so optimize it
811 ssleep(const volatile void *ident
, struct spinlock
*spin
, int flags
,
812 const char *wmesg
, int timo
)
814 globaldata_t gd
= mycpu
;
817 _tsleep_interlock(gd
, ident
, flags
);
818 spin_unlock_quick(gd
, spin
);
819 error
= tsleep(ident
, flags
| PINTERLOCKED
, wmesg
, timo
);
820 KKASSERT(gd
== mycpu
);
821 _spin_lock_quick(gd
, spin
, wmesg
);
827 lksleep(const volatile void *ident
, struct lock
*lock
, int flags
,
828 const char *wmesg
, int timo
)
830 globaldata_t gd
= mycpu
;
833 _tsleep_interlock(gd
, ident
, flags
);
834 lockmgr(lock
, LK_RELEASE
);
835 error
= tsleep(ident
, flags
| PINTERLOCKED
, wmesg
, timo
);
836 lockmgr(lock
, LK_EXCLUSIVE
);
842 * Interlocked mutex sleep. An exclusively held mutex must be passed
843 * to mtxsleep(). The function will atomically release the mutex
844 * and tsleep on the ident, then reacquire the mutex and return.
847 mtxsleep(const volatile void *ident
, struct mtx
*mtx
, int flags
,
848 const char *wmesg
, int timo
)
850 globaldata_t gd
= mycpu
;
853 _tsleep_interlock(gd
, ident
, flags
);
855 error
= tsleep(ident
, flags
| PINTERLOCKED
, wmesg
, timo
);
856 mtx_lock_ex_quick(mtx
);
862 * Interlocked serializer sleep. An exclusively held serializer must
863 * be passed to zsleep(). The function will atomically release
864 * the serializer and tsleep on the ident, then reacquire the serializer
868 zsleep(const volatile void *ident
, struct lwkt_serialize
*slz
, int flags
,
869 const char *wmesg
, int timo
)
871 globaldata_t gd
= mycpu
;
874 ASSERT_SERIALIZED(slz
);
876 _tsleep_interlock(gd
, ident
, flags
);
877 lwkt_serialize_exit(slz
);
878 ret
= tsleep(ident
, flags
| PINTERLOCKED
, wmesg
, timo
);
879 lwkt_serialize_enter(slz
);
885 * Directly block on the LWKT thread by descheduling it. This
886 * is much faster then tsleep(), but the only legal way to wake
887 * us up is to directly schedule the thread.
889 * Setting TDF_SINTR will cause new signals to directly schedule us.
891 * This routine must be called while in a critical section.
894 lwkt_sleep(const char *wmesg
, int flags
)
896 thread_t td
= curthread
;
899 if ((flags
& PCATCH
) == 0 || td
->td_lwp
== NULL
) {
900 td
->td_flags
|= TDF_BLOCKED
;
901 td
->td_wmesg
= wmesg
;
902 lwkt_deschedule_self(td
);
905 td
->td_flags
&= ~TDF_BLOCKED
;
908 if ((sig
= CURSIG(td
->td_lwp
)) != 0) {
909 if (SIGISMEMBER(td
->td_proc
->p_sigacts
->ps_sigintr
, sig
))
915 td
->td_flags
|= TDF_BLOCKED
| TDF_SINTR
;
916 td
->td_wmesg
= wmesg
;
917 lwkt_deschedule_self(td
);
919 td
->td_flags
&= ~(TDF_BLOCKED
| TDF_SINTR
);
925 * Implement the timeout for tsleep.
927 * This type of callout timeout is scheduled on the same cpu the process
928 * is sleeping on. Also, at the moment, the MP lock is held.
937 * We are going to have to get the lwp_token, which means we might
938 * block. This can race a tsleep getting woken up by other means
939 * so set TDF_TIMEOUT_RUNNING to force the tsleep to wait for our
940 * processing to complete (sorry tsleep!).
942 * We can safely set td_flags because td MUST be on the same cpu
945 KKASSERT(td
->td_gd
== mycpu
);
947 td
->td_flags
|= TDF_TIMEOUT_RUNNING
| TDF_TIMEOUT
;
950 * This can block but TDF_TIMEOUT_RUNNING will prevent the thread
951 * from exiting the tsleep on us. The flag is interlocked by virtue
952 * of lp being on the same cpu as we are.
954 if ((lp
= td
->td_lwp
) != NULL
)
955 lwkt_gettoken(&lp
->lwp_token
);
957 KKASSERT(td
->td_flags
& TDF_TSLEEP_DESCHEDULED
);
961 * callout timer should normally never be set in tstop()
962 * because it passes a timeout of 0. However, there is a
963 * case during thread exit (which SSTOP's all the threads)
964 * for which tstop() must break out and can (properly) leave
965 * the thread in LSSTOP.
967 KKASSERT(lp
->lwp_stat
!= LSSTOP
||
968 (lp
->lwp_mpflags
& LWP_MP_WEXIT
));
970 lwkt_reltoken(&lp
->lwp_token
);
975 KKASSERT(td
->td_gd
== mycpu
);
976 td
->td_flags
&= ~TDF_TIMEOUT_RUNNING
;
981 * Make all processes sleeping on the specified identifier runnable.
982 * count may be zero or one only.
984 * The domain encodes the sleep/wakeup domain, flags, plus the originating
987 * This call may run without the MP lock held. We can only manipulate thread
988 * state on the cpu owning the thread. We CANNOT manipulate process state
991 * _wakeup() can be passed to an IPI so we can't use (const volatile
995 _wakeup(void *ident
, int domain
)
1007 logtsleep2(wakeup_beg
, ident
);
1009 cid
= LOOKUP(ident
);
1010 gid
= TCHASHSHIFT(cid
);
1011 qp
= &gd
->gd_tsleep_hash
[gid
];
1013 for (td
= TAILQ_FIRST(&qp
->queue
); td
!= NULL
; td
= ntd
) {
1014 ntd
= TAILQ_NEXT(td
, td_sleepq
);
1015 if (td
->td_wchan
== ident
&&
1016 td
->td_wdomain
== (domain
& PDOMAIN_MASK
)
1018 KKASSERT(td
->td_gd
== gd
);
1020 td
->td_wakefromcpu
= PWAKEUP_DECODE(domain
);
1021 if (td
->td_flags
& TDF_TSLEEP_DESCHEDULED
) {
1023 if (domain
& PWAKEUP_ONE
)
1028 if (td
->td_wchan
== qp
->ident0
)
1030 else if (td
->td_wchan
== qp
->ident1
)
1032 else if (td
->td_wchan
== qp
->ident2
)
1034 else if (td
->td_wchan
== qp
->ident3
)
1037 wids
|= 16; /* force ident0 to be retained (-1) */
1041 * Because a bunch of cpumask array entries cover the same queue, it
1042 * is possible for our bit to remain set in some of them and cause
1043 * spurious wakeup IPIs later on. Make sure that the bit is cleared
1044 * when a spurious IPI occurs to prevent further spurious IPIs.
1046 if (TAILQ_FIRST(&qp
->queue
) == NULL
) {
1047 ATOMIC_CPUMASK_NANDBIT(slpque_cpumasks
[cid
], gd
->gd_cpuid
);
1053 if ((wids
& 1) == 0) {
1054 if ((wids
& 16) == 0) {
1057 KKASSERT(qp
->ident0
== (void *)(intptr_t)-1);
1060 if ((wids
& 2) == 0)
1062 if ((wids
& 4) == 0)
1064 if ((wids
& 8) == 0)
1069 * We finished checking the current cpu but there still may be
1070 * more work to do. Either wakeup_one was requested and no matching
1071 * thread was found, or a normal wakeup was requested and we have
1072 * to continue checking cpus.
1074 * It should be noted that this scheme is actually less expensive then
1075 * the old scheme when waking up multiple threads, since we send
1076 * only one IPI message per target candidate which may then schedule
1077 * multiple threads. Before we could have wound up sending an IPI
1078 * message for each thread on the target cpu (!= current cpu) that
1079 * needed to be woken up.
1081 * NOTE: Wakeups occuring on remote cpus are asynchronous. This
1082 * should be ok since we are passing idents in the IPI rather
1083 * then thread pointers.
1085 * NOTE: We MUST mfence (or use an atomic op) prior to reading
1086 * the cpumask, as another cpu may have written to it in
1087 * a fashion interlocked with whatever the caller did before
1088 * calling wakeup(). Otherwise we might miss the interaction
1089 * (kern_mutex.c can cause this problem).
1091 * lfence is insufficient as it may allow a written state to
1092 * reorder around the cpumask load.
1094 if ((domain
& PWAKEUP_MYCPU
) == 0) {
1096 const volatile void *id0
;
1101 mask
= slpque_cpumasks
[cid
];
1102 CPUMASK_ANDMASK(mask
, gd
->gd_other_cpus
);
1103 while (CPUMASK_TESTNZERO(mask
)) {
1104 n
= BSRCPUMASK(mask
);
1105 CPUMASK_NANDBIT(mask
, n
);
1106 tgd
= globaldata_find(n
);
1109 * Both ident0 compares must from a single load
1110 * to avoid ident0 update races crossing the two
1113 qp
= &tgd
->gd_tsleep_hash
[gid
];
1116 if (id0
== (void *)(intptr_t)-1) {
1117 lwkt_send_ipiq2(tgd
, _wakeup
, ident
,
1118 domain
| PWAKEUP_MYCPU
);
1119 ++tgd
->gd_cnt
.v_wakeup_colls
;
1120 } else if (id0
== ident
||
1121 qp
->ident1
== ident
||
1122 qp
->ident2
== ident
||
1123 qp
->ident3
== ident
) {
1124 lwkt_send_ipiq2(tgd
, _wakeup
, ident
,
1125 domain
| PWAKEUP_MYCPU
);
1129 if (CPUMASK_TESTNZERO(mask
)) {
1130 lwkt_send_ipiq2_mask(mask
, _wakeup
, ident
,
1131 domain
| PWAKEUP_MYCPU
);
1136 logtsleep1(wakeup_end
);
1141 * Wakeup all threads tsleep()ing on the specified ident, on all cpus
1144 wakeup(const volatile void *ident
)
1146 globaldata_t gd
= mycpu
;
1147 thread_t td
= gd
->gd_curthread
;
1149 if (td
&& (td
->td_flags
& TDF_DELAYED_WAKEUP
)) {
1151 * If we are in a delayed wakeup section, record up to two wakeups in
1152 * a per-CPU queue and issue them when we block or exit the delayed
1155 if (atomic_cmpset_ptr(&gd
->gd_delayed_wakeup
[0], NULL
, ident
))
1157 if (atomic_cmpset_ptr(&gd
->gd_delayed_wakeup
[1], NULL
, ident
))
1160 ident
= atomic_swap_ptr(__DEQUALIFY(volatile void **, &gd
->gd_delayed_wakeup
[1]),
1162 ident
= atomic_swap_ptr(__DEQUALIFY(volatile void **, &gd
->gd_delayed_wakeup
[0]),
1166 _wakeup(__DEALL(ident
), PWAKEUP_ENCODE(0, gd
->gd_cpuid
));
1170 * Wakeup one thread tsleep()ing on the specified ident, on any cpu.
1173 wakeup_one(const volatile void *ident
)
1175 /* XXX potentially round-robin the first responding cpu */
1176 _wakeup(__DEALL(ident
), PWAKEUP_ENCODE(0, mycpu
->gd_cpuid
) |
1181 * Wakeup threads tsleep()ing on the specified ident on the current cpu
1185 wakeup_mycpu(const volatile void *ident
)
1187 _wakeup(__DEALL(ident
), PWAKEUP_ENCODE(0, mycpu
->gd_cpuid
) |
1192 * Wakeup one thread tsleep()ing on the specified ident on the current cpu
1196 wakeup_mycpu_one(const volatile void *ident
)
1198 /* XXX potentially round-robin the first responding cpu */
1199 _wakeup(__DEALL(ident
), PWAKEUP_ENCODE(0, mycpu
->gd_cpuid
) |
1200 PWAKEUP_MYCPU
| PWAKEUP_ONE
);
1204 * Wakeup all thread tsleep()ing on the specified ident on the specified cpu
1208 wakeup_oncpu(globaldata_t gd
, const volatile void *ident
)
1210 globaldata_t mygd
= mycpu
;
1212 _wakeup(__DEALL(ident
), PWAKEUP_ENCODE(0, mygd
->gd_cpuid
) |
1215 lwkt_send_ipiq2(gd
, _wakeup
, __DEALL(ident
),
1216 PWAKEUP_ENCODE(0, mygd
->gd_cpuid
) |
1222 * Wakeup one thread tsleep()ing on the specified ident on the specified cpu
1226 wakeup_oncpu_one(globaldata_t gd
, const volatile void *ident
)
1228 globaldata_t mygd
= mycpu
;
1230 _wakeup(__DEALL(ident
), PWAKEUP_ENCODE(0, mygd
->gd_cpuid
) |
1231 PWAKEUP_MYCPU
| PWAKEUP_ONE
);
1233 lwkt_send_ipiq2(gd
, _wakeup
, __DEALL(ident
),
1234 PWAKEUP_ENCODE(0, mygd
->gd_cpuid
) |
1235 PWAKEUP_MYCPU
| PWAKEUP_ONE
);
1240 * Wakeup all threads waiting on the specified ident that slept using
1241 * the specified domain, on all cpus.
1244 wakeup_domain(const volatile void *ident
, int domain
)
1246 _wakeup(__DEALL(ident
), PWAKEUP_ENCODE(domain
, mycpu
->gd_cpuid
));
1250 * Wakeup one thread waiting on the specified ident that slept using
1251 * the specified domain, on any cpu.
1254 wakeup_domain_one(const volatile void *ident
, int domain
)
1256 /* XXX potentially round-robin the first responding cpu */
1257 _wakeup(__DEALL(ident
),
1258 PWAKEUP_ENCODE(domain
, mycpu
->gd_cpuid
) | PWAKEUP_ONE
);
1262 wakeup_start_delayed(void)
1264 globaldata_t gd
= mycpu
;
1267 gd
->gd_curthread
->td_flags
|= TDF_DELAYED_WAKEUP
;
1272 wakeup_end_delayed(void)
1274 globaldata_t gd
= mycpu
;
1276 if (gd
->gd_curthread
->td_flags
& TDF_DELAYED_WAKEUP
) {
1278 gd
->gd_curthread
->td_flags
&= ~TDF_DELAYED_WAKEUP
;
1279 if (gd
->gd_delayed_wakeup
[0] || gd
->gd_delayed_wakeup
[1]) {
1280 if (gd
->gd_delayed_wakeup
[0]) {
1281 wakeup(gd
->gd_delayed_wakeup
[0]);
1282 gd
->gd_delayed_wakeup
[0] = NULL
;
1284 if (gd
->gd_delayed_wakeup
[1]) {
1285 wakeup(gd
->gd_delayed_wakeup
[1]);
1286 gd
->gd_delayed_wakeup
[1] = NULL
;
1296 * Make a process runnable. lp->lwp_token must be held on call and this
1297 * function must be called from the cpu owning lp.
1299 * This only has an effect if we are in LSSTOP or LSSLEEP.
1302 setrunnable(struct lwp
*lp
)
1304 thread_t td
= lp
->lwp_thread
;
1306 ASSERT_LWKT_TOKEN_HELD(&lp
->lwp_token
);
1307 KKASSERT(td
->td_gd
== mycpu
);
1309 if (lp
->lwp_stat
== LSSTOP
)
1310 lp
->lwp_stat
= LSSLEEP
;
1311 if (lp
->lwp_stat
== LSSLEEP
) {
1314 } else if (td
->td_flags
& TDF_SINTR
) {
1321 * The process is stopped due to some condition, usually because p_stat is
1322 * set to SSTOP, but also possibly due to being traced.
1324 * Caller must hold p->p_token
1326 * NOTE! If the caller sets SSTOP, the caller must also clear P_WAITED
1327 * because the parent may check the child's status before the child actually
1328 * gets to this routine.
1330 * This routine is called with the current lwp only, typically just
1331 * before returning to userland if the process state is detected as
1332 * possibly being in a stopped state.
1337 struct lwp
*lp
= curthread
->td_lwp
;
1338 struct proc
*p
= lp
->lwp_proc
;
1341 lwkt_gettoken(&lp
->lwp_token
);
1345 * If LWP_MP_WSTOP is set, we were sleeping
1346 * while our process was stopped. At this point
1347 * we were already counted as stopped.
1349 if ((lp
->lwp_mpflags
& LWP_MP_WSTOP
) == 0) {
1351 * If we're the last thread to stop, signal
1355 atomic_set_int(&lp
->lwp_mpflags
, LWP_MP_WSTOP
);
1356 wakeup(&p
->p_nstopped
);
1357 if (p
->p_nstopped
== p
->p_nthreads
) {
1359 * Token required to interlock kern_wait()
1363 lwkt_gettoken(&q
->p_token
);
1364 p
->p_flags
&= ~P_WAITED
;
1366 if ((q
->p_sigacts
->ps_flag
& PS_NOCLDSTOP
) == 0)
1367 ksignal(q
, SIGCHLD
);
1368 lwkt_reltoken(&q
->p_token
);
1374 * Wait here while in a stopped state, interlocked with lwp_token.
1375 * We must break-out if the whole process is trying to exit.
1377 while (STOPLWP(p
, lp
)) {
1378 lp
->lwp_stat
= LSSTOP
;
1379 tsleep(p
, 0, "stop", 0);
1382 atomic_clear_int(&lp
->lwp_mpflags
, LWP_MP_WSTOP
);
1384 lwkt_reltoken(&lp
->lwp_token
);
1388 * Compute a tenex style load average of a quantity on
1389 * 1, 5 and 15 minute intervals. This is a pcpu callout.
1391 * We segment the lwp scan on a pcpu basis. This does NOT
1392 * mean the associated lwps are on this cpu, it is done
1393 * just to break the work up.
1395 * The callout on cpu0 rolls up the stats from the other
1398 static int loadav_count_runnable(struct lwp
*p
, void *data
);
1403 globaldata_t gd
= mycpu
;
1404 struct loadavg
*avg
;
1408 alllwp_scan(loadav_count_runnable
, &nrun
, 1);
1409 gd
->gd_loadav_nrunnable
= nrun
;
1410 if (gd
->gd_cpuid
== 0) {
1413 for (i
= 0; i
< ncpus
; ++i
)
1414 nrun
+= globaldata_find(i
)->gd_loadav_nrunnable
;
1415 for (i
= 0; i
< 3; i
++) {
1416 avg
->ldavg
[i
] = (cexp
[i
] * avg
->ldavg
[i
] +
1417 (long)nrun
* FSCALE
* (FSCALE
- cexp
[i
])) >> FSHIFT
;
1422 * Schedule the next update to occur after 5 seconds, but add a
1423 * random variation to avoid synchronisation with processes that
1424 * run at regular intervals.
1426 callout_reset(&gd
->gd_loadav_callout
,
1427 hz
* 4 + (int)(krandom() % (hz
* 2 + 1)),
1432 loadav_count_runnable(struct lwp
*lp
, void *data
)
1437 switch (lp
->lwp_stat
) {
1439 if ((td
= lp
->lwp_thread
) == NULL
)
1441 if (td
->td_flags
& TDF_BLOCKED
)
1453 * Regular data collection
1456 collect_load_callback(int n
)
1458 int fscale
= averunnable
.fscale
;
1460 return ((averunnable
.ldavg
[0] * 100 + (fscale
>> 1)) / fscale
);
1464 sched_setup(void *dummy __unused
)
1466 globaldata_t save_gd
= mycpu
;
1470 kcollect_register(KCOLLECT_LOAD
, "load", collect_load_callback
,
1471 KCOLLECT_SCALE(KCOLLECT_LOAD_FORMAT
, 0));
1474 * Kick off timeout driven events by calling first time. We
1475 * split the work across available cpus to help scale it,
1476 * it can eat a lot of cpu when there are a lot of processes
1479 for (n
= 0; n
< ncpus
; ++n
) {
1480 gd
= globaldata_find(n
);
1481 lwkt_setcpu_self(gd
);
1482 callout_init_mp(&gd
->gd_loadav_callout
);
1483 callout_init_mp(&gd
->gd_schedcpu_callout
);
1487 lwkt_setcpu_self(save_gd
);
1491 * Extremely early initialization, dummy-up the tables so we don't have
1492 * to conditionalize for NULL in _wakeup() and tsleep_interlock(). Even
1493 * though the system isn't blocking this early, these functions still
1494 * try to access the hash table.
1496 * This setup will be overridden once sched_dyninit() -> sleep_gdinit()
1500 sleep_early_gdinit(globaldata_t gd
)
1502 static struct tslpque dummy_slpque
;
1503 static cpumask_t dummy_cpumasks
;
1505 slpque_tablesize
= 1;
1506 gd
->gd_tsleep_hash
= &dummy_slpque
;
1507 slpque_cpumasks
= &dummy_cpumasks
;
1508 TAILQ_INIT(&dummy_slpque
.queue
);
1512 * PCPU initialization. Called after KMALLOC is operational, by
1513 * sched_dyninit() for cpu 0, and by mi_gdinit() for other cpus later.
1515 * WARNING! The pcpu hash table is smaller than the global cpumask
1516 * hash table, which can save us a lot of memory when maxproc
1520 sleep_gdinit(globaldata_t gd
)
1528 * This shouldn't happen, that is there shouldn't be any threads
1529 * waiting on the dummy tsleep queue this early in the boot.
1531 if (gd
->gd_cpuid
== 0) {
1532 struct tslpque
*qp
= &gd
->gd_tsleep_hash
[0];
1533 TAILQ_FOREACH(td
, &qp
->queue
, td_sleepq
) {
1534 kprintf("SLEEP_GDINIT SWITCH %s\n", td
->td_comm
);
1539 * Note that we have to allocate one extra slot because we are
1540 * shifting a modulo value. TCHASHSHIFT(slpque_tablesize - 1) can
1541 * return the same value as TCHASHSHIFT(slpque_tablesize).
1543 n
= TCHASHSHIFT(slpque_tablesize
) + 1;
1545 hash_size
= sizeof(struct tslpque
) * n
;
1546 gd
->gd_tsleep_hash
= (void *)kmem_alloc3(&kernel_map
, hash_size
,
1548 KM_CPU(gd
->gd_cpuid
));
1549 memset(gd
->gd_tsleep_hash
, 0, hash_size
);
1550 for (i
= 0; i
< n
; ++i
)
1551 TAILQ_INIT(&gd
->gd_tsleep_hash
[i
].queue
);
1555 * Dynamic initialization after the memory system is operational.
1558 sched_dyninit(void *dummy __unused
)
1565 * Calculate table size for slpque hash. We want a prime number
1566 * large enough to avoid overloading slpque_cpumasks when the
1567 * system has a large number of sleeping processes, which will
1568 * spam IPIs on wakeup().
1570 * While it is true this is really a per-lwp factor, generally
1571 * speaking the maxproc limit is a good metric to go by.
1573 for (tblsize
= maxproc
| 1; ; tblsize
+= 2) {
1574 if (tblsize
% 3 == 0)
1576 if (tblsize
% 5 == 0)
1578 tblsize2
= (tblsize
/ 2) | 1;
1579 for (n
= 7; n
< tblsize2
; n
+= 2) {
1580 if (tblsize
% n
== 0)
1588 * PIDs are currently limited to 6 digits. Cap the table size
1591 if (tblsize
> 2000003)
1594 slpque_tablesize
= tblsize
;
1595 slpque_cpumasks
= kmalloc(sizeof(*slpque_cpumasks
) * slpque_tablesize
,
1596 M_TSLEEP
, M_WAITOK
| M_ZERO
);
1597 sleep_gdinit(mycpu
);