6b6ba96b60
in specific situations. The owner thread must be blocked, and the borrower can not proceed back to user space with the borrowed KSE. The borrower will return the KSE on the next context switch where teh owner wants it back. This removes a lot of possible race conditions and deadlocks. It is consceivable that the borrower should inherit the priority of the owner too. that's another discussion and would be simple to do. Also, as part of this, the "preallocatd spare thread" is attached to the thread doing a syscall rather than the KSE. This removes the need to lock the scheduler when we want to access it, as it's now "at hand". DDB now shows a lot mor info for threaded proceses though it may need some optimisation to squeeze it all back into 80 chars again. (possible JKH project) Upcalls are now "bound" threads, but "KSE Lending" now means that other completing syscalls can be completed using that KSE before the upcall finally makes it back to the UTS. (getting threads OUT OF THE KERNEL is one of the highest priorities in the KSE system.) The upcall when it happens will present all the completed syscalls to the KSE for selection.
1045 lines
29 KiB
C
1045 lines
29 KiB
C
/*-
|
|
* Copyright (c) 1982, 1986, 1990, 1991, 1993
|
|
* The Regents of the University of California. All rights reserved.
|
|
* (c) UNIX System Laboratories, Inc.
|
|
* All or some portions of this file are derived from material licensed
|
|
* to the University of California by American Telephone and Telegraph
|
|
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
|
|
* the permission of UNIX System Laboratories, Inc.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
* 3. All advertising materials mentioning features or use of this software
|
|
* must display the following acknowledgement:
|
|
* This product includes software developed by the University of
|
|
* California, Berkeley and its contributors.
|
|
* 4. Neither the name of the University nor the names of its contributors
|
|
* may be used to endorse or promote products derived from this software
|
|
* without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
|
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
|
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
* SUCH DAMAGE.
|
|
*
|
|
* @(#)kern_synch.c 8.9 (Berkeley) 5/19/95
|
|
* $FreeBSD$
|
|
*/
|
|
|
|
#include "opt_ddb.h"
|
|
#include "opt_ktrace.h"
|
|
|
|
#include <sys/param.h>
|
|
#include <sys/systm.h>
|
|
#include <sys/condvar.h>
|
|
#include <sys/kernel.h>
|
|
#include <sys/ktr.h>
|
|
#include <sys/lock.h>
|
|
#include <sys/mutex.h>
|
|
#include <sys/proc.h>
|
|
#include <sys/resourcevar.h>
|
|
#include <sys/signalvar.h>
|
|
#include <sys/smp.h>
|
|
#include <sys/sx.h>
|
|
#include <sys/sysctl.h>
|
|
#include <sys/sysproto.h>
|
|
#include <sys/vmmeter.h>
|
|
#ifdef DDB
|
|
#include <ddb/ddb.h>
|
|
#endif
|
|
#ifdef KTRACE
|
|
#include <sys/uio.h>
|
|
#include <sys/ktrace.h>
|
|
#endif
|
|
|
|
#include <machine/cpu.h>
|
|
|
|
static void sched_setup(void *dummy);
|
|
SYSINIT(sched_setup, SI_SUB_KICK_SCHEDULER, SI_ORDER_FIRST, sched_setup, NULL)
|
|
|
|
int hogticks;
|
|
int lbolt;
|
|
int sched_quantum; /* Roundrobin scheduling quantum in ticks. */
|
|
|
|
static struct callout loadav_callout;
|
|
static struct callout schedcpu_callout;
|
|
static struct callout roundrobin_callout;
|
|
|
|
struct loadavg averunnable =
|
|
{ {0, 0, 0}, FSCALE }; /* load average, of runnable procs */
|
|
/*
|
|
* Constants for averages over 1, 5, and 15 minutes
|
|
* when sampling at 5 second intervals.
|
|
*/
|
|
static fixpt_t cexp[3] = {
|
|
0.9200444146293232 * FSCALE, /* exp(-1/12) */
|
|
0.9834714538216174 * FSCALE, /* exp(-1/60) */
|
|
0.9944598480048967 * FSCALE, /* exp(-1/180) */
|
|
};
|
|
|
|
static void endtsleep(void *);
|
|
static void loadav(void *arg);
|
|
static void roundrobin(void *arg);
|
|
static void schedcpu(void *arg);
|
|
|
|
static int
|
|
sysctl_kern_quantum(SYSCTL_HANDLER_ARGS)
|
|
{
|
|
int error, new_val;
|
|
|
|
new_val = sched_quantum * tick;
|
|
error = sysctl_handle_int(oidp, &new_val, 0, req);
|
|
if (error != 0 || req->newptr == NULL)
|
|
return (error);
|
|
if (new_val < tick)
|
|
return (EINVAL);
|
|
sched_quantum = new_val / tick;
|
|
hogticks = 2 * sched_quantum;
|
|
return (0);
|
|
}
|
|
|
|
SYSCTL_PROC(_kern, OID_AUTO, quantum, CTLTYPE_INT|CTLFLAG_RW,
|
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0, sizeof sched_quantum, sysctl_kern_quantum, "I",
|
|
"Roundrobin scheduling quantum in microseconds");
|
|
|
|
/*
|
|
* Arrange to reschedule if necessary, taking the priorities and
|
|
* schedulers into account.
|
|
*/
|
|
void
|
|
maybe_resched(struct thread *td)
|
|
{
|
|
|
|
mtx_assert(&sched_lock, MA_OWNED);
|
|
if (td->td_priority < curthread->td_priority)
|
|
curthread->td_kse->ke_flags |= KEF_NEEDRESCHED;
|
|
}
|
|
|
|
int
|
|
roundrobin_interval(void)
|
|
{
|
|
return (sched_quantum);
|
|
}
|
|
|
|
/*
|
|
* Force switch among equal priority processes every 100ms.
|
|
* We don't actually need to force a context switch of the current process.
|
|
* The act of firing the event triggers a context switch to softclock() and
|
|
* then switching back out again which is equivalent to a preemption, thus
|
|
* no further work is needed on the local CPU.
|
|
*/
|
|
/* ARGSUSED */
|
|
static void
|
|
roundrobin(arg)
|
|
void *arg;
|
|
{
|
|
|
|
#ifdef SMP
|
|
mtx_lock_spin(&sched_lock);
|
|
forward_roundrobin();
|
|
mtx_unlock_spin(&sched_lock);
|
|
#endif
|
|
|
|
callout_reset(&roundrobin_callout, sched_quantum, roundrobin, NULL);
|
|
}
|
|
|
|
/*
|
|
* Constants for digital decay and forget:
|
|
* 90% of (p_estcpu) usage in 5 * loadav time
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|
* 95% of (p_pctcpu) usage in 60 seconds (load insensitive)
|
|
* Note that, as ps(1) mentions, this can let percentages
|
|
* total over 100% (I've seen 137.9% for 3 processes).
|
|
*
|
|
* Note that schedclock() updates p_estcpu and p_cpticks asynchronously.
|
|
*
|
|
* We wish to decay away 90% of p_estcpu in (5 * loadavg) seconds.
|
|
* That is, the system wants to compute a value of decay such
|
|
* that the following for loop:
|
|
* for (i = 0; i < (5 * loadavg); i++)
|
|
* p_estcpu *= decay;
|
|
* will compute
|
|
* p_estcpu *= 0.1;
|
|
* for all values of loadavg:
|
|
*
|
|
* Mathematically this loop can be expressed by saying:
|
|
* decay ** (5 * loadavg) ~= .1
|
|
*
|
|
* The system computes decay as:
|
|
* decay = (2 * loadavg) / (2 * loadavg + 1)
|
|
*
|
|
* We wish to prove that the system's computation of decay
|
|
* will always fulfill the equation:
|
|
* decay ** (5 * loadavg) ~= .1
|
|
*
|
|
* If we compute b as:
|
|
* b = 2 * loadavg
|
|
* then
|
|
* decay = b / (b + 1)
|
|
*
|
|
* We now need to prove two things:
|
|
* 1) Given factor ** (5 * loadavg) ~= .1, prove factor == b/(b+1)
|
|
* 2) Given b/(b+1) ** power ~= .1, prove power == (5 * loadavg)
|
|
*
|
|
* Facts:
|
|
* For x close to zero, exp(x) =~ 1 + x, since
|
|
* exp(x) = 0! + x**1/1! + x**2/2! + ... .
|
|
* therefore exp(-1/b) =~ 1 - (1/b) = (b-1)/b.
|
|
* For x close to zero, ln(1+x) =~ x, since
|
|
* ln(1+x) = x - x**2/2 + x**3/3 - ... -1 < x < 1
|
|
* therefore ln(b/(b+1)) = ln(1 - 1/(b+1)) =~ -1/(b+1).
|
|
* ln(.1) =~ -2.30
|
|
*
|
|
* Proof of (1):
|
|
* Solve (factor)**(power) =~ .1 given power (5*loadav):
|
|
* solving for factor,
|
|
* ln(factor) =~ (-2.30/5*loadav), or
|
|
* factor =~ exp(-1/((5/2.30)*loadav)) =~ exp(-1/(2*loadav)) =
|
|
* exp(-1/b) =~ (b-1)/b =~ b/(b+1). QED
|
|
*
|
|
* Proof of (2):
|
|
* Solve (factor)**(power) =~ .1 given factor == (b/(b+1)):
|
|
* solving for power,
|
|
* power*ln(b/(b+1)) =~ -2.30, or
|
|
* power =~ 2.3 * (b + 1) = 4.6*loadav + 2.3 =~ 5*loadav. QED
|
|
*
|
|
* Actual power values for the implemented algorithm are as follows:
|
|
* loadav: 1 2 3 4
|
|
* power: 5.68 10.32 14.94 19.55
|
|
*/
|
|
|
|
/* calculations for digital decay to forget 90% of usage in 5*loadav sec */
|
|
#define loadfactor(loadav) (2 * (loadav))
|
|
#define decay_cpu(loadfac, cpu) (((loadfac) * (cpu)) / ((loadfac) + FSCALE))
|
|
|
|
/* decay 95% of `p_pctcpu' in 60 seconds; see CCPU_SHIFT before changing */
|
|
static fixpt_t ccpu = 0.95122942450071400909 * FSCALE; /* exp(-1/20) */
|
|
SYSCTL_INT(_kern, OID_AUTO, ccpu, CTLFLAG_RD, &ccpu, 0, "");
|
|
|
|
/* kernel uses `FSCALE', userland (SHOULD) use kern.fscale */
|
|
static int fscale __unused = FSCALE;
|
|
SYSCTL_INT(_kern, OID_AUTO, fscale, CTLFLAG_RD, 0, FSCALE, "");
|
|
|
|
/*
|
|
* If `ccpu' is not equal to `exp(-1/20)' and you still want to use the
|
|
* faster/more-accurate formula, you'll have to estimate CCPU_SHIFT below
|
|
* and possibly adjust FSHIFT in "param.h" so that (FSHIFT >= CCPU_SHIFT).
|
|
*
|
|
* To estimate CCPU_SHIFT for exp(-1/20), the following formula was used:
|
|
* 1 - exp(-1/20) ~= 0.0487 ~= 0.0488 == 1 (fixed pt, *11* bits).
|
|
*
|
|
* If you don't want to bother with the faster/more-accurate formula, you
|
|
* can set CCPU_SHIFT to (FSHIFT + 1) which will use a slower/less-accurate
|
|
* (more general) method of calculating the %age of CPU used by a process.
|
|
*/
|
|
#define CCPU_SHIFT 11
|
|
|
|
/*
|
|
* Recompute process priorities, every hz ticks.
|
|
* MP-safe, called without the Giant mutex.
|
|
*/
|
|
/* ARGSUSED */
|
|
static void
|
|
schedcpu(arg)
|
|
void *arg;
|
|
{
|
|
register fixpt_t loadfac = loadfactor(averunnable.ldavg[0]);
|
|
struct thread *td;
|
|
struct proc *p;
|
|
struct kse *ke;
|
|
struct ksegrp *kg;
|
|
int realstathz;
|
|
int awake;
|
|
|
|
realstathz = stathz ? stathz : hz;
|
|
sx_slock(&allproc_lock);
|
|
FOREACH_PROC_IN_SYSTEM(p) {
|
|
mtx_lock_spin(&sched_lock);
|
|
p->p_swtime++;
|
|
FOREACH_KSEGRP_IN_PROC(p, kg) {
|
|
awake = 0;
|
|
FOREACH_KSE_IN_GROUP(kg, ke) {
|
|
/*
|
|
* Increment time in/out of memory and sleep
|
|
* time (if sleeping). We ignore overflow;
|
|
* with 16-bit int's (remember them?)
|
|
* overflow takes 45 days.
|
|
*/
|
|
/*
|
|
* The kse slptimes are not touched in wakeup
|
|
* because the thread may not HAVE a KSE.
|
|
*/
|
|
if (ke->ke_state == KES_ONRUNQ) {
|
|
awake = 1;
|
|
ke->ke_flags &= ~KEF_DIDRUN;
|
|
} else if ((ke->ke_state == KES_THREAD) &&
|
|
(TD_IS_RUNNING(ke->ke_thread))) {
|
|
awake = 1;
|
|
/* Do not clear KEF_DIDRUN */
|
|
} else if (ke->ke_flags & KEF_DIDRUN) {
|
|
awake = 1;
|
|
ke->ke_flags &= ~KEF_DIDRUN;
|
|
}
|
|
|
|
/*
|
|
* pctcpu is only for ps?
|
|
* Do it per kse.. and add them up at the end?
|
|
* XXXKSE
|
|
*/
|
|
ke->ke_pctcpu
|
|
= (ke->ke_pctcpu * ccpu) >> FSHIFT;
|
|
/*
|
|
* If the kse has been idle the entire second,
|
|
* stop recalculating its priority until
|
|
* it wakes up.
|
|
*/
|
|
if (ke->ke_cpticks == 0)
|
|
continue;
|
|
#if (FSHIFT >= CCPU_SHIFT)
|
|
ke->ke_pctcpu += (realstathz == 100) ?
|
|
((fixpt_t) ke->ke_cpticks) <<
|
|
(FSHIFT - CCPU_SHIFT) :
|
|
100 * (((fixpt_t) ke->ke_cpticks) <<
|
|
(FSHIFT - CCPU_SHIFT)) / realstathz;
|
|
#else
|
|
ke->ke_pctcpu += ((FSCALE - ccpu) *
|
|
(ke->ke_cpticks * FSCALE / realstathz)) >>
|
|
FSHIFT;
|
|
#endif
|
|
ke->ke_cpticks = 0;
|
|
} /* end of kse loop */
|
|
/*
|
|
* If there are ANY running threads in this KSEGRP,
|
|
* then don't count it as sleeping.
|
|
*/
|
|
if (awake) {
|
|
if (kg->kg_slptime > 1) {
|
|
/*
|
|
* In an ideal world, this should not
|
|
* happen, because whoever woke us
|
|
* up from the long sleep should have
|
|
* unwound the slptime and reset our
|
|
* priority before we run at the stale
|
|
* priority. Should KASSERT at some
|
|
* point when all the cases are fixed.
|
|
*/
|
|
updatepri(kg);
|
|
}
|
|
kg->kg_slptime = 0;
|
|
} else {
|
|
kg->kg_slptime++;
|
|
}
|
|
if (kg->kg_slptime > 1)
|
|
continue;
|
|
kg->kg_estcpu = decay_cpu(loadfac, kg->kg_estcpu);
|
|
resetpriority(kg);
|
|
FOREACH_THREAD_IN_GROUP(kg, td) {
|
|
int changedqueue;
|
|
if (td->td_priority >= PUSER) {
|
|
/*
|
|
* Only change the priority
|
|
* of threads that are still at their
|
|
* user priority.
|
|
* XXXKSE This is problematic
|
|
* as we may need to re-order
|
|
* the threads on the KSEG list.
|
|
*/
|
|
changedqueue =
|
|
((td->td_priority / RQ_PPQ) !=
|
|
(kg->kg_user_pri / RQ_PPQ));
|
|
|
|
td->td_priority = kg->kg_user_pri;
|
|
if (changedqueue && TD_ON_RUNQ(td)) {
|
|
/* this could be optimised */
|
|
remrunqueue(td);
|
|
td->td_priority =
|
|
kg->kg_user_pri;
|
|
setrunqueue(td);
|
|
} else {
|
|
td->td_priority = kg->kg_user_pri;
|
|
}
|
|
}
|
|
}
|
|
} /* end of ksegrp loop */
|
|
mtx_unlock_spin(&sched_lock);
|
|
} /* end of process loop */
|
|
sx_sunlock(&allproc_lock);
|
|
wakeup(&lbolt);
|
|
callout_reset(&schedcpu_callout, hz, schedcpu, NULL);
|
|
}
|
|
|
|
/*
|
|
* Recalculate the priority of a process after it has slept for a while.
|
|
* For all load averages >= 1 and max p_estcpu of 255, sleeping for at
|
|
* least six times the loadfactor will decay p_estcpu to zero.
|
|
*/
|
|
void
|
|
updatepri(struct ksegrp *kg)
|
|
{
|
|
register unsigned int newcpu;
|
|
register fixpt_t loadfac = loadfactor(averunnable.ldavg[0]);
|
|
|
|
newcpu = kg->kg_estcpu;
|
|
if (kg->kg_slptime > 5 * loadfac)
|
|
kg->kg_estcpu = 0;
|
|
else {
|
|
kg->kg_slptime--; /* the first time was done in schedcpu */
|
|
while (newcpu && --kg->kg_slptime)
|
|
newcpu = decay_cpu(loadfac, newcpu);
|
|
kg->kg_estcpu = newcpu;
|
|
}
|
|
resetpriority(kg);
|
|
}
|
|
|
|
/*
|
|
* We're only looking at 7 bits of the address; everything is
|
|
* aligned to 4, lots of things are aligned to greater powers
|
|
* of 2. Shift right by 8, i.e. drop the bottom 256 worth.
|
|
*/
|
|
#define TABLESIZE 128
|
|
static TAILQ_HEAD(slpquehead, thread) slpque[TABLESIZE];
|
|
#define LOOKUP(x) (((intptr_t)(x) >> 8) & (TABLESIZE - 1))
|
|
|
|
void
|
|
sleepinit(void)
|
|
{
|
|
int i;
|
|
|
|
sched_quantum = hz/10;
|
|
hogticks = 2 * sched_quantum;
|
|
for (i = 0; i < TABLESIZE; i++)
|
|
TAILQ_INIT(&slpque[i]);
|
|
}
|
|
|
|
/*
|
|
* General sleep call. Suspends the current process until a wakeup is
|
|
* performed on the specified identifier. The process will then be made
|
|
* runnable with the specified priority. Sleeps at most timo/hz seconds
|
|
* (0 means no timeout). If pri includes PCATCH flag, signals are checked
|
|
* before and after sleeping, else signals are not checked. Returns 0 if
|
|
* awakened, EWOULDBLOCK if the timeout expires. If PCATCH is set and a
|
|
* signal needs to be delivered, ERESTART is returned if the current system
|
|
* call should be restarted if possible, and EINTR is returned if the system
|
|
* call should be interrupted by the signal (return EINTR).
|
|
*
|
|
* The mutex argument is exited before the caller is suspended, and
|
|
* entered before msleep returns. If priority includes the PDROP
|
|
* flag the mutex is not entered before returning.
|
|
*/
|
|
|
|
int
|
|
msleep(ident, mtx, priority, wmesg, timo)
|
|
void *ident;
|
|
struct mtx *mtx;
|
|
int priority, timo;
|
|
const char *wmesg;
|
|
{
|
|
struct thread *td = curthread;
|
|
struct proc *p = td->td_proc;
|
|
int sig, catch = priority & PCATCH;
|
|
int rval = 0;
|
|
WITNESS_SAVE_DECL(mtx);
|
|
|
|
#ifdef KTRACE
|
|
if (KTRPOINT(td, KTR_CSW))
|
|
ktrcsw(1, 0);
|
|
#endif
|
|
WITNESS_SLEEP(0, &mtx->mtx_object);
|
|
KASSERT(timo != 0 || mtx_owned(&Giant) || mtx != NULL,
|
|
("sleeping without a mutex"));
|
|
/*
|
|
* If we are capable of async syscalls and there isn't already
|
|
* another one ready to return, start a new thread
|
|
* and queue it as ready to run. Note that there is danger here
|
|
* because we need to make sure that we don't sleep allocating
|
|
* the thread (recursion here might be bad).
|
|
* Hence the TDF_INMSLEEP flag.
|
|
*/
|
|
if (p->p_flag & P_KSES) {
|
|
/* Just don't bother if we are exiting
|
|
and not the exiting thread. */
|
|
if ((p->p_flag & P_WEXIT) && catch && p->p_singlethread != td)
|
|
return (EINTR);
|
|
if (td->td_mailbox && (!(td->td_flags & TDF_INMSLEEP))) {
|
|
/*
|
|
* Arrange for an upcall to be readied.
|
|
* it will not actually happen until all
|
|
* pending in-kernel work for this KSEGRP
|
|
* has been done.
|
|
*/
|
|
mtx_lock_spin(&sched_lock);
|
|
/* Don't recurse here! */
|
|
td->td_flags |= TDF_INMSLEEP;
|
|
thread_schedule_upcall(td, td->td_kse);
|
|
td->td_flags &= ~TDF_INMSLEEP;
|
|
mtx_unlock_spin(&sched_lock);
|
|
}
|
|
}
|
|
mtx_lock_spin(&sched_lock);
|
|
if (cold ) {
|
|
/*
|
|
* During autoconfiguration, just give interrupts
|
|
* a chance, then just return.
|
|
* Don't run any other procs or panic below,
|
|
* in case this is the idle process and already asleep.
|
|
*/
|
|
if (mtx != NULL && priority & PDROP)
|
|
mtx_unlock(mtx);
|
|
mtx_unlock_spin(&sched_lock);
|
|
return (0);
|
|
}
|
|
|
|
DROP_GIANT();
|
|
|
|
if (mtx != NULL) {
|
|
mtx_assert(mtx, MA_OWNED | MA_NOTRECURSED);
|
|
WITNESS_SAVE(&mtx->mtx_object, mtx);
|
|
mtx_unlock(mtx);
|
|
if (priority & PDROP)
|
|
mtx = NULL;
|
|
}
|
|
|
|
KASSERT(p != NULL, ("msleep1"));
|
|
KASSERT(ident != NULL && TD_IS_RUNNING(td), ("msleep"));
|
|
|
|
CTR5(KTR_PROC, "msleep: thread %p (pid %d, %s) on %s (%p)",
|
|
td, p->p_pid, p->p_comm, wmesg, ident);
|
|
|
|
td->td_wchan = ident;
|
|
td->td_wmesg = wmesg;
|
|
td->td_ksegrp->kg_slptime = 0;
|
|
td->td_priority = priority & PRIMASK;
|
|
TAILQ_INSERT_TAIL(&slpque[LOOKUP(ident)], td, td_slpq);
|
|
TD_SET_ON_SLEEPQ(td);
|
|
if (timo)
|
|
callout_reset(&td->td_slpcallout, timo, endtsleep, td);
|
|
/*
|
|
* We put ourselves on the sleep queue and start our timeout
|
|
* before calling thread_suspend_check, as we could stop there, and
|
|
* a wakeup or a SIGCONT (or both) could occur while we were stopped.
|
|
* without resuming us, thus we must be ready for sleep
|
|
* when cursig is called. If the wakeup happens while we're
|
|
* stopped, td->td_wchan will be 0 upon return from cursig.
|
|
*/
|
|
if (catch) {
|
|
CTR3(KTR_PROC, "msleep caught: thread %p (pid %d, %s)", td,
|
|
p->p_pid, p->p_comm);
|
|
td->td_flags |= TDF_SINTR;
|
|
mtx_unlock_spin(&sched_lock);
|
|
PROC_LOCK(p);
|
|
sig = cursig(td);
|
|
if (sig == 0 && thread_suspend_check(1))
|
|
sig = SIGSTOP;
|
|
mtx_lock_spin(&sched_lock);
|
|
PROC_UNLOCK(p);
|
|
if (sig != 0) {
|
|
if (TD_ON_SLEEPQ(td))
|
|
unsleep(td);
|
|
} else if (!TD_ON_SLEEPQ(td))
|
|
catch = 0;
|
|
} else
|
|
sig = 0;
|
|
if (TD_ON_SLEEPQ(td)) {
|
|
p->p_stats->p_ru.ru_nvcsw++;
|
|
TD_SET_SLEEPING(td);
|
|
mi_switch();
|
|
}
|
|
CTR3(KTR_PROC, "msleep resume: thread %p (pid %d, %s)", td, p->p_pid,
|
|
p->p_comm);
|
|
KASSERT(TD_IS_RUNNING(td), ("running but not TDS_RUNNING"));
|
|
td->td_flags &= ~TDF_SINTR;
|
|
if (td->td_flags & TDF_TIMEOUT) {
|
|
td->td_flags &= ~TDF_TIMEOUT;
|
|
if (sig == 0)
|
|
rval = EWOULDBLOCK;
|
|
} else if (td->td_flags & TDF_TIMOFAIL) {
|
|
td->td_flags &= ~TDF_TIMOFAIL;
|
|
} else if (timo && callout_stop(&td->td_slpcallout) == 0) {
|
|
/*
|
|
* This isn't supposed to be pretty. If we are here, then
|
|
* the endtsleep() callout is currently executing on another
|
|
* CPU and is either spinning on the sched_lock or will be
|
|
* soon. If we don't synchronize here, there is a chance
|
|
* that this process may msleep() again before the callout
|
|
* has a chance to run and the callout may end up waking up
|
|
* the wrong msleep(). Yuck.
|
|
*/
|
|
TD_SET_SLEEPING(td);
|
|
p->p_stats->p_ru.ru_nivcsw++;
|
|
mi_switch();
|
|
td->td_flags &= ~TDF_TIMOFAIL;
|
|
}
|
|
mtx_unlock_spin(&sched_lock);
|
|
|
|
if (rval == 0 && catch) {
|
|
PROC_LOCK(p);
|
|
/* XXX: shouldn't we always be calling cursig() */
|
|
if (sig != 0 || (sig = cursig(td))) {
|
|
if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig))
|
|
rval = EINTR;
|
|
else
|
|
rval = ERESTART;
|
|
}
|
|
PROC_UNLOCK(p);
|
|
}
|
|
#ifdef KTRACE
|
|
if (KTRPOINT(td, KTR_CSW))
|
|
ktrcsw(0, 0);
|
|
#endif
|
|
PICKUP_GIANT();
|
|
if (mtx != NULL) {
|
|
mtx_lock(mtx);
|
|
WITNESS_RESTORE(&mtx->mtx_object, mtx);
|
|
}
|
|
return (rval);
|
|
}
|
|
|
|
/*
|
|
* Implement timeout for msleep()
|
|
*
|
|
* If process hasn't been awakened (wchan non-zero),
|
|
* set timeout flag and undo the sleep. If proc
|
|
* is stopped, just unsleep so it will remain stopped.
|
|
* MP-safe, called without the Giant mutex.
|
|
*/
|
|
static void
|
|
endtsleep(arg)
|
|
void *arg;
|
|
{
|
|
register struct thread *td = arg;
|
|
|
|
CTR3(KTR_PROC, "endtsleep: thread %p (pid %d, %s)",
|
|
td, td->td_proc->p_pid, td->td_proc->p_comm);
|
|
mtx_lock_spin(&sched_lock);
|
|
/*
|
|
* This is the other half of the synchronization with msleep()
|
|
* described above. If the TDS_TIMEOUT flag is set, we lost the
|
|
* race and just need to put the process back on the runqueue.
|
|
*/
|
|
if (TD_ON_SLEEPQ(td)) {
|
|
TAILQ_REMOVE(&slpque[LOOKUP(td->td_wchan)], td, td_slpq);
|
|
TD_CLR_ON_SLEEPQ(td);
|
|
td->td_flags |= TDF_TIMEOUT;
|
|
} else {
|
|
td->td_flags |= TDF_TIMOFAIL;
|
|
}
|
|
TD_CLR_SLEEPING(td);
|
|
setrunnable(td);
|
|
mtx_unlock_spin(&sched_lock);
|
|
}
|
|
|
|
/*
|
|
* Abort a thread, as if an interrupt had occured. Only abort
|
|
* interruptable waits (unfortunatly it isn't only safe to abort others).
|
|
* This is about identical to cv_abort().
|
|
* Think about merging them?
|
|
* Also, whatever the signal code does...
|
|
*/
|
|
void
|
|
abortsleep(struct thread *td)
|
|
{
|
|
|
|
mtx_assert(&sched_lock, MA_OWNED);
|
|
/*
|
|
* If the TDF_TIMEOUT flag is set, just leave. A
|
|
* timeout is scheduled anyhow.
|
|
*/
|
|
if ((td->td_flags & (TDF_TIMEOUT | TDF_SINTR)) == TDF_SINTR) {
|
|
if (TD_ON_SLEEPQ(td)) {
|
|
unsleep(td);
|
|
TD_CLR_SLEEPING(td);
|
|
setrunnable(td);
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Remove a process from its wait queue
|
|
*/
|
|
void
|
|
unsleep(struct thread *td)
|
|
{
|
|
|
|
mtx_lock_spin(&sched_lock);
|
|
if (TD_ON_SLEEPQ(td)) {
|
|
TAILQ_REMOVE(&slpque[LOOKUP(td->td_wchan)], td, td_slpq);
|
|
TD_CLR_ON_SLEEPQ(td);
|
|
}
|
|
mtx_unlock_spin(&sched_lock);
|
|
}
|
|
|
|
/*
|
|
* Make all processes sleeping on the specified identifier runnable.
|
|
*/
|
|
void
|
|
wakeup(ident)
|
|
register void *ident;
|
|
{
|
|
register struct slpquehead *qp;
|
|
register struct thread *td;
|
|
struct thread *ntd;
|
|
struct proc *p;
|
|
|
|
mtx_lock_spin(&sched_lock);
|
|
qp = &slpque[LOOKUP(ident)];
|
|
restart:
|
|
for (td = TAILQ_FIRST(qp); td != NULL; td = ntd) {
|
|
ntd = TAILQ_NEXT(td, td_slpq);
|
|
if (td->td_wchan == ident) {
|
|
unsleep(td);
|
|
TD_CLR_SLEEPING(td);
|
|
setrunnable(td);
|
|
p = td->td_proc;
|
|
CTR3(KTR_PROC,"wakeup: thread %p (pid %d, %s)",
|
|
td, p->p_pid, p->p_comm);
|
|
goto restart;
|
|
}
|
|
}
|
|
mtx_unlock_spin(&sched_lock);
|
|
}
|
|
|
|
/*
|
|
* Make a process sleeping on the specified identifier runnable.
|
|
* May wake more than one process if a target process is currently
|
|
* swapped out.
|
|
*/
|
|
void
|
|
wakeup_one(ident)
|
|
register void *ident;
|
|
{
|
|
register struct slpquehead *qp;
|
|
register struct thread *td;
|
|
register struct proc *p;
|
|
struct thread *ntd;
|
|
|
|
mtx_lock_spin(&sched_lock);
|
|
qp = &slpque[LOOKUP(ident)];
|
|
for (td = TAILQ_FIRST(qp); td != NULL; td = ntd) {
|
|
ntd = TAILQ_NEXT(td, td_slpq);
|
|
if (td->td_wchan == ident) {
|
|
unsleep(td);
|
|
TD_CLR_SLEEPING(td);
|
|
setrunnable(td);
|
|
p = td->td_proc;
|
|
CTR3(KTR_PROC,"wakeup1: thread %p (pid %d, %s)",
|
|
td, p->p_pid, p->p_comm);
|
|
break;
|
|
}
|
|
}
|
|
mtx_unlock_spin(&sched_lock);
|
|
}
|
|
|
|
/*
|
|
* The machine independent parts of mi_switch().
|
|
*/
|
|
void
|
|
mi_switch(void)
|
|
{
|
|
struct bintime new_switchtime;
|
|
struct thread *td = curthread; /* XXX */
|
|
struct proc *p = td->td_proc; /* XXX */
|
|
struct kse *ke = td->td_kse;
|
|
u_int sched_nest;
|
|
|
|
mtx_assert(&sched_lock, MA_OWNED | MA_NOTRECURSED);
|
|
KASSERT((ke->ke_state == KES_THREAD), ("mi_switch: kse state?"));
|
|
KASSERT(!TD_ON_RUNQ(td), ("mi_switch: called by old code"));
|
|
#ifdef INVARIANTS
|
|
if (!TD_ON_LOCK(td) &&
|
|
!TD_ON_RUNQ(td) &&
|
|
!TD_IS_RUNNING(td))
|
|
mtx_assert(&Giant, MA_NOTOWNED);
|
|
#endif
|
|
KASSERT(td->td_critnest == 1,
|
|
("mi_switch: switch in a critical section"));
|
|
|
|
/*
|
|
* Compute the amount of time during which the current
|
|
* process was running, and add that to its total so far.
|
|
*/
|
|
binuptime(&new_switchtime);
|
|
bintime_add(&p->p_runtime, &new_switchtime);
|
|
bintime_sub(&p->p_runtime, PCPU_PTR(switchtime));
|
|
|
|
#ifdef DDB
|
|
/*
|
|
* Don't perform context switches from the debugger.
|
|
*/
|
|
if (db_active) {
|
|
mtx_unlock_spin(&sched_lock);
|
|
db_error("Context switches not allowed in the debugger.");
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* Check if the process exceeds its cpu resource allocation. If
|
|
* over max, arrange to kill the process in ast().
|
|
*
|
|
* XXX The checking for p_limit being NULL here is totally bogus,
|
|
* but hides something easy to trip over, as a result of us switching
|
|
* after the limit has been freed/set-to-NULL. A KASSERT() will be
|
|
* appropriate once this is no longer a bug, to watch for regression.
|
|
*/
|
|
if (p->p_state != PRS_ZOMBIE && p->p_limit != NULL &&
|
|
p->p_limit->p_cpulimit != RLIM_INFINITY &&
|
|
p->p_runtime.sec > p->p_limit->p_cpulimit) {
|
|
p->p_sflag |= PS_XCPU;
|
|
ke->ke_flags |= KEF_ASTPENDING;
|
|
}
|
|
|
|
/*
|
|
* Finish up stats for outgoing thread.
|
|
*/
|
|
cnt.v_swtch++;
|
|
PCPU_SET(switchtime, new_switchtime);
|
|
CTR3(KTR_PROC, "mi_switch: old thread %p (pid %d, %s)", td, p->p_pid,
|
|
p->p_comm);
|
|
sched_nest = sched_lock.mtx_recurse;
|
|
td->td_lastcpu = ke->ke_oncpu;
|
|
ke->ke_oncpu = NOCPU;
|
|
ke->ke_flags &= ~KEF_NEEDRESCHED;
|
|
/*
|
|
* At the last moment, if this thread is still marked RUNNING,
|
|
* then put it back on the run queue as it has not been suspended
|
|
* or stopped or any thing else similar.
|
|
*/
|
|
if (TD_IS_RUNNING(td)) {
|
|
/* Put us back on the run queue (kse and all). */
|
|
setrunqueue(td);
|
|
} else if (p->p_flag & P_KSES) {
|
|
/*
|
|
* We will not be on the run queue. So we must be
|
|
* sleeping or similar. As it's available,
|
|
* someone else can use the KSE if they need it.
|
|
* (If bound LOANING can still occur).
|
|
*/
|
|
kse_reassign(ke);
|
|
}
|
|
|
|
cpu_switch(); /* SHAZAM!!*/
|
|
|
|
/*
|
|
* Start setting up stats etc. for the incoming thread.
|
|
* Similar code in fork_exit() is returned to by cpu_switch()
|
|
* in the case of a new thread/process.
|
|
*/
|
|
td->td_kse->ke_oncpu = PCPU_GET(cpuid);
|
|
sched_lock.mtx_recurse = sched_nest;
|
|
sched_lock.mtx_lock = (uintptr_t)td;
|
|
CTR3(KTR_PROC, "mi_switch: new thread %p (pid %d, %s)", td, p->p_pid,
|
|
p->p_comm);
|
|
if (PCPU_GET(switchtime.sec) == 0)
|
|
binuptime(PCPU_PTR(switchtime));
|
|
PCPU_SET(switchticks, ticks);
|
|
|
|
/*
|
|
* Call the switchin function while still holding the scheduler lock
|
|
* (used by the idlezero code and the general page-zeroing code)
|
|
*/
|
|
if (td->td_switchin)
|
|
td->td_switchin();
|
|
}
|
|
|
|
/*
|
|
* Change process state to be runnable,
|
|
* placing it on the run queue if it is in memory,
|
|
* and awakening the swapper if it isn't in memory.
|
|
*/
|
|
void
|
|
setrunnable(struct thread *td)
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
struct ksegrp *kg;
|
|
|
|
mtx_assert(&sched_lock, MA_OWNED);
|
|
switch (p->p_state) {
|
|
case PRS_ZOMBIE:
|
|
panic("setrunnable(1)");
|
|
default:
|
|
break;
|
|
}
|
|
switch (td->td_state) {
|
|
case TDS_RUNNING:
|
|
case TDS_RUNQ:
|
|
return;
|
|
case TDS_INHIBITED:
|
|
/*
|
|
* If we are only inhibited because we are swapped out
|
|
* then arange to swap in this process. Otherwise just return.
|
|
*/
|
|
if (td->td_inhibitors != TDI_SWAPPED)
|
|
return;
|
|
case TDS_CAN_RUN:
|
|
break;
|
|
default:
|
|
printf("state is 0x%x", td->td_state);
|
|
panic("setrunnable(2)");
|
|
}
|
|
if ((p->p_sflag & PS_INMEM) == 0) {
|
|
if ((p->p_sflag & PS_SWAPPINGIN) == 0) {
|
|
p->p_sflag |= PS_SWAPINREQ;
|
|
wakeup(&proc0);
|
|
}
|
|
} else {
|
|
kg = td->td_ksegrp;
|
|
if (kg->kg_slptime > 1)
|
|
updatepri(kg);
|
|
kg->kg_slptime = 0;
|
|
setrunqueue(td);
|
|
maybe_resched(td);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Compute the priority of a process when running in user mode.
|
|
* Arrange to reschedule if the resulting priority is better
|
|
* than that of the current process.
|
|
*/
|
|
void
|
|
resetpriority(kg)
|
|
register struct ksegrp *kg;
|
|
{
|
|
register unsigned int newpriority;
|
|
struct thread *td;
|
|
|
|
mtx_lock_spin(&sched_lock);
|
|
if (kg->kg_pri_class == PRI_TIMESHARE) {
|
|
newpriority = PUSER + kg->kg_estcpu / INVERSE_ESTCPU_WEIGHT +
|
|
NICE_WEIGHT * (kg->kg_nice - PRIO_MIN);
|
|
newpriority = min(max(newpriority, PRI_MIN_TIMESHARE),
|
|
PRI_MAX_TIMESHARE);
|
|
kg->kg_user_pri = newpriority;
|
|
}
|
|
FOREACH_THREAD_IN_GROUP(kg, td) {
|
|
maybe_resched(td); /* XXXKSE silly */
|
|
}
|
|
mtx_unlock_spin(&sched_lock);
|
|
}
|
|
|
|
/*
|
|
* Compute a tenex style load average of a quantity on
|
|
* 1, 5 and 15 minute intervals.
|
|
* XXXKSE Needs complete rewrite when correct info is available.
|
|
* Completely Bogus.. only works with 1:1 (but compiles ok now :-)
|
|
*/
|
|
static void
|
|
loadav(void *arg)
|
|
{
|
|
int i, nrun;
|
|
struct loadavg *avg;
|
|
struct proc *p;
|
|
struct thread *td;
|
|
|
|
avg = &averunnable;
|
|
sx_slock(&allproc_lock);
|
|
nrun = 0;
|
|
FOREACH_PROC_IN_SYSTEM(p) {
|
|
FOREACH_THREAD_IN_PROC(p, td) {
|
|
switch (td->td_state) {
|
|
case TDS_RUNQ:
|
|
case TDS_RUNNING:
|
|
if ((p->p_flag & P_NOLOAD) != 0)
|
|
goto nextproc;
|
|
nrun++; /* XXXKSE */
|
|
default:
|
|
break;
|
|
}
|
|
nextproc:
|
|
continue;
|
|
}
|
|
}
|
|
sx_sunlock(&allproc_lock);
|
|
for (i = 0; i < 3; i++)
|
|
avg->ldavg[i] = (cexp[i] * avg->ldavg[i] +
|
|
nrun * FSCALE * (FSCALE - cexp[i])) >> FSHIFT;
|
|
|
|
/*
|
|
* Schedule the next update to occur after 5 seconds, but add a
|
|
* random variation to avoid synchronisation with processes that
|
|
* run at regular intervals.
|
|
*/
|
|
callout_reset(&loadav_callout, hz * 4 + (int)(random() % (hz * 2 + 1)),
|
|
loadav, NULL);
|
|
}
|
|
|
|
/* ARGSUSED */
|
|
static void
|
|
sched_setup(dummy)
|
|
void *dummy;
|
|
{
|
|
|
|
callout_init(&schedcpu_callout, 1);
|
|
callout_init(&roundrobin_callout, 0);
|
|
callout_init(&loadav_callout, 0);
|
|
|
|
/* Kick off timeout driven events by calling first time. */
|
|
roundrobin(NULL);
|
|
schedcpu(NULL);
|
|
loadav(NULL);
|
|
}
|
|
|
|
/*
|
|
* We adjust the priority of the current process. The priority of
|
|
* a process gets worse as it accumulates CPU time. The cpu usage
|
|
* estimator (p_estcpu) is increased here. resetpriority() will
|
|
* compute a different priority each time p_estcpu increases by
|
|
* INVERSE_ESTCPU_WEIGHT
|
|
* (until MAXPRI is reached). The cpu usage estimator ramps up
|
|
* quite quickly when the process is running (linearly), and decays
|
|
* away exponentially, at a rate which is proportionally slower when
|
|
* the system is busy. The basic principle is that the system will
|
|
* 90% forget that the process used a lot of CPU time in 5 * loadav
|
|
* seconds. This causes the system to favor processes which haven't
|
|
* run much recently, and to round-robin among other processes.
|
|
*/
|
|
void
|
|
schedclock(td)
|
|
struct thread *td;
|
|
{
|
|
struct kse *ke;
|
|
struct ksegrp *kg;
|
|
|
|
KASSERT((td != NULL), ("schedclock: null thread pointer"));
|
|
ke = td->td_kse;
|
|
kg = td->td_ksegrp;
|
|
ke->ke_cpticks++;
|
|
kg->kg_estcpu = ESTCPULIM(kg->kg_estcpu + 1);
|
|
if ((kg->kg_estcpu % INVERSE_ESTCPU_WEIGHT) == 0) {
|
|
resetpriority(kg);
|
|
if (td->td_priority >= PUSER)
|
|
td->td_priority = kg->kg_user_pri;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* General purpose yield system call
|
|
*/
|
|
int
|
|
yield(struct thread *td, struct yield_args *uap)
|
|
{
|
|
struct ksegrp *kg = td->td_ksegrp;
|
|
|
|
mtx_assert(&Giant, MA_NOTOWNED);
|
|
mtx_lock_spin(&sched_lock);
|
|
td->td_priority = PRI_MAX_TIMESHARE;
|
|
kg->kg_proc->p_stats->p_ru.ru_nvcsw++;
|
|
mi_switch();
|
|
mtx_unlock_spin(&sched_lock);
|
|
td->td_retval[0] = 0;
|
|
|
|
return (0);
|
|
}
|
|
|