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freebsd-skq/sys/kern/sched_4bsd.c

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/*-
* 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.
* 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/ktr.h>
#include <sys/lock.h>
#include <sys/kthread.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/resourcevar.h>
#include <sys/sched.h>
#include <sys/smp.h>
#include <sys/sysctl.h>
#include <sys/sx.h>
#define KTR_4BSD 0x0
/*
* INVERSE_ESTCPU_WEIGHT is only suitable for statclock() frequencies in
* the range 100-256 Hz (approximately).
*/
#define ESTCPULIM(e) \
min((e), INVERSE_ESTCPU_WEIGHT * (NICE_WEIGHT * (PRIO_MAX - PRIO_MIN) - \
RQ_PPQ) + INVERSE_ESTCPU_WEIGHT - 1)
#ifdef SMP
#define INVERSE_ESTCPU_WEIGHT (8 * smp_cpus)
#else
#define INVERSE_ESTCPU_WEIGHT 8 /* 1 / (priorities per estcpu level). */
#endif
#define NICE_WEIGHT 1 /* Priorities per nice level. */
struct ke_sched {
int ske_cpticks; /* (j) Ticks of cpu time. */
struct runq *ske_runq; /* runq the kse is currently on */
};
#define ke_runq ke_sched->ske_runq
#define KEF_BOUND KEF_SCHED1
#define SKE_RUNQ_PCPU(ke) \
((ke)->ke_runq != 0 && (ke)->ke_runq != &runq)
/*
* KSE_CAN_MIGRATE macro returns true if the kse can migrate between
* cpus.
*/
#define KSE_CAN_MIGRATE(ke) \
((ke)->ke_thread->td_pinned == 0 && ((ke)->ke_flags & KEF_BOUND) == 0)
static struct ke_sched ke_sched;
struct ke_sched *kse0_sched = &ke_sched;
struct kg_sched *ksegrp0_sched = NULL;
struct p_sched *proc0_sched = NULL;
struct td_sched *thread0_sched = NULL;
static int sched_tdcnt; /* Total runnable threads in the system. */
static int sched_quantum; /* Roundrobin scheduling quantum in ticks. */
#define SCHED_QUANTUM (hz / 10) /* Default sched quantum */
static struct callout roundrobin_callout;
static void setup_runqs(void);
static void roundrobin(void *arg);
static void schedcpu(void);
static void schedcpu_thread(void);
static void sched_setup(void *dummy);
static void maybe_resched(struct thread *td);
static void updatepri(struct ksegrp *kg);
static void resetpriority(struct ksegrp *kg);
static struct kproc_desc sched_kp = {
"schedcpu",
schedcpu_thread,
NULL
};
SYSINIT(schedcpu, SI_SUB_RUN_SCHEDULER, SI_ORDER_FIRST, kproc_start, &sched_kp)
SYSINIT(sched_setup, SI_SUB_RUN_QUEUE, SI_ORDER_FIRST, sched_setup, NULL)
/*
* Global run queue.
*/
static struct runq runq;
#ifdef SMP
/*
* Per-CPU run queues
*/
static struct runq runq_pcpu[MAXCPU];
#endif
static void
setup_runqs(void)
{
#ifdef SMP
int i;
for (i = 0; i < MAXCPU; ++i)
runq_init(&runq_pcpu[i]);
#endif
runq_init(&runq);
}
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_NODE(_kern, OID_AUTO, sched, CTLFLAG_RD, 0, "SCHED");
#define SCHD_NAME "4bsd"
#define SCHD_NAME_LEN 4
SYSCTL_STRING(_kern_sched, OID_AUTO, name, CTLFALG_RD, SCHD_NAME, SCHD_NAME_LEN,
"System is using the 4BSD scheduler");
SYSCTL_PROC(_kern_sched, OID_AUTO, quantum, CTLTYPE_INT|CTLFLAG_RW,
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.
*/
static void
maybe_resched(struct thread *td)
{
mtx_assert(&sched_lock, MA_OWNED);
if (td->td_priority < curthread->td_priority && curthread->td_kse)
curthread->td_flags |= TDF_NEEDRESCHED;
}
/*
* 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(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 (kg_estcpu) usage in 5 * loadav time
* 95% of (ke_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 kg_estcpu and p_cpticks asynchronously.
*
* We wish to decay away 90% of kg_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++)
* kg_estcpu *= decay;
* will compute
* kg_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 `ke_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, "");
/*
* 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(void)
{
register fixpt_t loadfac = loadfactor(averunnable.ldavg[0]);
struct thread *td;
struct proc *p;
struct kse *ke;
struct ksegrp *kg;
int awake, realstathz;
realstathz = stathz ? stathz : hz;
sx_slock(&allproc_lock);
FOREACH_PROC_IN_SYSTEM(p) {
/*
* Prevent state changes and protect run queue.
*/
mtx_lock_spin(&sched_lock);
/*
* Increment time in/out of memory. We ignore overflow; with
* 16-bit int's (remember them?) overflow takes 45 days.
*/
p->p_swtime++;
FOREACH_KSEGRP_IN_PROC(p, kg) {
awake = 0;
FOREACH_KSE_IN_GROUP(kg, ke) {
/*
* Increment sleep time (if sleeping). We
* ignore overflow, as above.
*/
/*
* 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;
}
/*
* ke_pctcpu is only for ps and ttyinfo().
* 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_sched->ske_cpticks == 0)
continue;
#if (FSHIFT >= CCPU_SHIFT)
ke->ke_pctcpu += (realstathz == 100)
? ((fixpt_t) ke->ke_sched->ske_cpticks) <<
(FSHIFT - CCPU_SHIFT) :
100 * (((fixpt_t) ke->ke_sched->ske_cpticks)
<< (FSHIFT - CCPU_SHIFT)) / realstathz;
#else
ke->ke_pctcpu += ((FSCALE - ccpu) *
(ke->ke_sched->ske_cpticks *
FSCALE / realstathz)) >> FSHIFT;
#endif
ke->ke_sched->ske_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) {
if (td->td_priority >= PUSER) {
sched_prio(td, kg->kg_user_pri);
}
}
} /* end of ksegrp loop */
mtx_unlock_spin(&sched_lock);
} /* end of process loop */
sx_sunlock(&allproc_lock);
}
/*
* Main loop for a kthread that executes schedcpu once a second.
*/
static void
schedcpu_thread(void)
{
int nowake;
for (;;) {
schedcpu();
tsleep(&nowake, curthread->td_priority, "-", hz);
}
}
/*
* Recalculate the priority of a process after it has slept for a while.
* For all load averages >= 1 and max kg_estcpu of 255, sleeping for at
* least six times the loadfactor will decay kg_estcpu to zero.
*/
static void
updatepri(struct ksegrp *kg)
{
register fixpt_t loadfac;
register unsigned int newcpu;
loadfac = loadfactor(averunnable.ldavg[0]);
if (kg->kg_slptime > 5 * loadfac)
kg->kg_estcpu = 0;
else {
newcpu = kg->kg_estcpu;
kg->kg_slptime--; /* was incremented in schedcpu() */
while (newcpu && --kg->kg_slptime)
newcpu = decay_cpu(loadfac, newcpu);
kg->kg_estcpu = newcpu;
}
resetpriority(kg);
}
/*
* 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.
*/
static void
resetpriority(struct ksegrp *kg)
{
register unsigned int newpriority;
struct thread *td;
if (kg->kg_pri_class == PRI_TIMESHARE) {
newpriority = PUSER + kg->kg_estcpu / INVERSE_ESTCPU_WEIGHT +
NICE_WEIGHT * (kg->kg_proc->p_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 */
}
}
/* ARGSUSED */
static void
sched_setup(void *dummy)
{
setup_runqs();
if (sched_quantum == 0)
sched_quantum = SCHED_QUANTUM;
hogticks = 2 * sched_quantum;
callout_init(&roundrobin_callout, CALLOUT_MPSAFE);
/* Kick off timeout driven events by calling first time. */
roundrobin(NULL);
/* Account for thread0. */
sched_tdcnt++;
}
/* External interfaces start here */
int
sched_runnable(void)
{
#ifdef SMP
return runq_check(&runq) + runq_check(&runq_pcpu[PCPU_GET(cpuid)]);
#else
return runq_check(&runq);
#endif
}
int
sched_rr_interval(void)
{
if (sched_quantum == 0)
sched_quantum = SCHED_QUANTUM;
return (sched_quantum);
}
/*
* We adjust the priority of the current process. The priority of
* a process gets worse as it accumulates CPU time. The cpu usage
* estimator (kg_estcpu) is increased here. resetpriority() will
* compute a different priority each time kg_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
sched_clock(struct thread *td)
{
struct ksegrp *kg;
struct kse *ke;
mtx_assert(&sched_lock, MA_OWNED);
kg = td->td_ksegrp;
ke = td->td_kse;
ke->ke_sched->ske_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;
}
}
/*
* charge childs scheduling cpu usage to parent.
*
* XXXKSE assume only one thread & kse & ksegrp keep estcpu in each ksegrp.
* Charge it to the ksegrp that did the wait since process estcpu is sum of
* all ksegrps, this is strictly as expected. Assume that the child process
* aggregated all the estcpu into the 'built-in' ksegrp.
*/
void
sched_exit(struct proc *p, struct proc *p1)
{
sched_exit_kse(FIRST_KSE_IN_PROC(p), FIRST_KSE_IN_PROC(p1));
sched_exit_ksegrp(FIRST_KSEGRP_IN_PROC(p), FIRST_KSEGRP_IN_PROC(p1));
sched_exit_thread(FIRST_THREAD_IN_PROC(p), FIRST_THREAD_IN_PROC(p1));
}
void
sched_exit_kse(struct kse *ke, struct kse *child)
{
}
void
sched_exit_ksegrp(struct ksegrp *kg, struct ksegrp *child)
{
mtx_assert(&sched_lock, MA_OWNED);
kg->kg_estcpu = ESTCPULIM(kg->kg_estcpu + child->kg_estcpu);
}
void
sched_exit_thread(struct thread *td, struct thread *child)
{
if ((child->td_proc->p_flag & P_NOLOAD) == 0)
sched_tdcnt--;
}
void
sched_fork(struct proc *p, struct proc *p1)
{
sched_fork_kse(FIRST_KSE_IN_PROC(p), FIRST_KSE_IN_PROC(p1));
sched_fork_ksegrp(FIRST_KSEGRP_IN_PROC(p), FIRST_KSEGRP_IN_PROC(p1));
sched_fork_thread(FIRST_THREAD_IN_PROC(p), FIRST_THREAD_IN_PROC(p1));
}
void
sched_fork_kse(struct kse *ke, struct kse *child)
{
child->ke_sched->ske_cpticks = 0;
}
void
sched_fork_ksegrp(struct ksegrp *kg, struct ksegrp *child)
{
mtx_assert(&sched_lock, MA_OWNED);
child->kg_estcpu = kg->kg_estcpu;
}
void
sched_fork_thread(struct thread *td, struct thread *child)
{
}
void
sched_nice(struct proc *p, int nice)
{
struct ksegrp *kg;
PROC_LOCK_ASSERT(p, MA_OWNED);
mtx_assert(&sched_lock, MA_OWNED);
p->p_nice = nice;
FOREACH_KSEGRP_IN_PROC(p, kg) {
resetpriority(kg);
}
}
void
sched_class(struct ksegrp *kg, int class)
{
mtx_assert(&sched_lock, MA_OWNED);
kg->kg_pri_class = class;
}
/*
* Adjust the priority of a thread.
* This may include moving the thread within the KSEGRP,
* changing the assignment of a kse to the thread,
* and moving a KSE in the system run queue.
*/
void
sched_prio(struct thread *td, u_char prio)
{
mtx_assert(&sched_lock, MA_OWNED);
if (TD_ON_RUNQ(td)) {
adjustrunqueue(td, prio);
} else {
td->td_priority = prio;
}
}
void
sched_sleep(struct thread *td)
{
mtx_assert(&sched_lock, MA_OWNED);
td->td_ksegrp->kg_slptime = 0;
td->td_base_pri = td->td_priority;
}
void
sched_switch(struct thread *td)
{
struct thread *newtd;
struct kse *ke;
struct proc *p;
ke = td->td_kse;
p = td->td_proc;
mtx_assert(&sched_lock, MA_OWNED);
KASSERT((ke->ke_state == KES_THREAD), ("sched_switch: kse state?"));
if ((p->p_flag & P_NOLOAD) == 0)
sched_tdcnt--;
td->td_lastcpu = td->td_oncpu;
td->td_last_kse = ke;
td->td_flags &= ~TDF_NEEDRESCHED;
td->td_oncpu = NOCPU;
/*
* 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_SA) {
/*
* 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.
*/
kse_reassign(ke);
}
newtd = choosethread();
if (td != newtd)
cpu_switch(td, newtd);
sched_lock.mtx_lock = (uintptr_t)td;
td->td_oncpu = PCPU_GET(cpuid);
}
void
sched_wakeup(struct thread *td)
{
struct ksegrp *kg;
mtx_assert(&sched_lock, MA_OWNED);
kg = td->td_ksegrp;
if (kg->kg_slptime > 1)
updatepri(kg);
kg->kg_slptime = 0;
setrunqueue(td);
maybe_resched(td);
}
void
sched_add(struct thread *td)
{
struct kse *ke;
ke = td->td_kse;
mtx_assert(&sched_lock, MA_OWNED);
KASSERT((ke->ke_thread != NULL), ("sched_add: No thread on KSE"));
KASSERT((ke->ke_thread->td_kse != NULL),
("sched_add: No KSE on thread"));
KASSERT(ke->ke_state != KES_ONRUNQ,
("sched_add: kse %p (%s) already in run queue", ke,
ke->ke_proc->p_comm));
KASSERT(ke->ke_proc->p_sflag & PS_INMEM,
("sched_add: process swapped out"));
ke->ke_ksegrp->kg_runq_kses++;
ke->ke_state = KES_ONRUNQ;
#ifdef SMP
if (KSE_CAN_MIGRATE(ke)) {
CTR1(KTR_4BSD, "adding kse:%p to gbl runq", ke);
ke->ke_runq = &runq;
} else {
CTR1(KTR_4BSD, "adding kse:%p to pcpu runq", ke);
if (!SKE_RUNQ_PCPU(ke))
ke->ke_runq = &runq_pcpu[PCPU_GET(cpuid)];
}
#else
ke->ke_runq = &runq;
#endif
if ((td->td_proc->p_flag & P_NOLOAD) == 0)
sched_tdcnt++;
runq_add(ke->ke_runq, ke);
}
void
sched_rem(struct thread *td)
{
struct kse *ke;
ke = td->td_kse;
KASSERT(ke->ke_proc->p_sflag & PS_INMEM,
("sched_rem: process swapped out"));
KASSERT((ke->ke_state == KES_ONRUNQ),
("sched_rem: KSE not on run queue"));
mtx_assert(&sched_lock, MA_OWNED);
if ((td->td_proc->p_flag & P_NOLOAD) == 0)
sched_tdcnt--;
runq_remove(ke->ke_sched->ske_runq, ke);
ke->ke_state = KES_THREAD;
ke->ke_ksegrp->kg_runq_kses--;
}
struct kse *
sched_choose(void)
{
struct kse *ke;
struct runq *rq;
#ifdef SMP
struct kse *kecpu;
rq = &runq;
ke = runq_choose(&runq);
kecpu = runq_choose(&runq_pcpu[PCPU_GET(cpuid)]);
if (ke == NULL ||
(kecpu != NULL &&
kecpu->ke_thread->td_priority < ke->ke_thread->td_priority)) {
CTR2(KTR_4BSD, "choosing kse %p from pcpu runq %d", kecpu,
PCPU_GET(cpuid));
ke = kecpu;
rq = &runq_pcpu[PCPU_GET(cpuid)];
} else {
CTR1(KTR_4BSD, "choosing kse %p from main runq", ke);
}
#else
rq = &runq;
ke = runq_choose(&runq);
#endif
if (ke != NULL) {
runq_remove(rq, ke);
ke->ke_state = KES_THREAD;
KASSERT((ke->ke_thread != NULL),
("sched_choose: No thread on KSE"));
KASSERT((ke->ke_thread->td_kse != NULL),
("sched_choose: No KSE on thread"));
KASSERT(ke->ke_proc->p_sflag & PS_INMEM,
("sched_choose: process swapped out"));
}
return (ke);
}
void
sched_userret(struct thread *td)
{
struct ksegrp *kg;
/*
* XXX we cheat slightly on the locking here to avoid locking in
* the usual case. Setting td_priority here is essentially an
* incomplete workaround for not setting it properly elsewhere.
* Now that some interrupt handlers are threads, not setting it
* properly elsewhere can clobber it in the window between setting
* it here and returning to user mode, so don't waste time setting
* it perfectly here.
*/
kg = td->td_ksegrp;
if (td->td_priority != kg->kg_user_pri) {
mtx_lock_spin(&sched_lock);
td->td_priority = kg->kg_user_pri;
mtx_unlock_spin(&sched_lock);
}
}
void
sched_bind(struct thread *td, int cpu)
{
struct kse *ke;
mtx_assert(&sched_lock, MA_OWNED);
KASSERT(TD_IS_RUNNING(td),
("sched_bind: cannot bind non-running thread"));
ke = td->td_kse;
ke->ke_flags |= KEF_BOUND;
#ifdef SMP
ke->ke_runq = &runq_pcpu[cpu];
if (PCPU_GET(cpuid) == cpu)
return;
ke->ke_state = KES_THREAD;
mi_switch(SW_VOL);
#endif
}
void
sched_unbind(struct thread* td)
{
mtx_assert(&sched_lock, MA_OWNED);
td->td_kse->ke_flags &= ~KEF_BOUND;
}
int
sched_load(void)
{
return (sched_tdcnt);
}
int
sched_sizeof_kse(void)
{
return (sizeof(struct kse) + sizeof(struct ke_sched));
}
int
sched_sizeof_ksegrp(void)
{
return (sizeof(struct ksegrp));
}
int
sched_sizeof_proc(void)
{
return (sizeof(struct proc));
}
int
sched_sizeof_thread(void)
{
return (sizeof(struct thread));
}
fixpt_t
sched_pctcpu(struct thread *td)
{
struct kse *ke;
ke = td->td_kse;
if (ke == NULL)
ke = td->td_last_kse;
if (ke)
return (ke->ke_pctcpu);
return (0);
}
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