007ddf7e7a
have been unified with that of msleep(9), further refine the sleepq interface and consolidate some duplicated code: - Move the pre-sleep checks for theaded processes into a thread_sleep_check() function in kern_thread.c. - Move all handling of TDF_SINTR to be internal to subr_sleepqueue.c. Specifically, if a thread is awakened by something other than a signal while checking for signals before going to sleep, clear TDF_SINTR in sleepq_catch_signals(). This removes a sched_lock lock/unlock combo in that edge case during an interruptible sleep. Also, fix sleepq_check_signals() to properly handle the condition if TDF_SINTR is clear rather than requiring the callers of the sleepq API to notice this edge case and call a non-_sig variant of sleepq_wait(). - Clarify the flags arguments to sleepq_add(), sleepq_signal() and sleepq_broadcast() by creating an explicit submask for sleepq types. Also, add an explicit SLEEPQ_MSLEEP type rather than a magic number of 0. Also, add a SLEEPQ_INTERRUPTIBLE flag for use with sleepq_add() and move the setting of TDF_SINTR to sleepq_add() if this flag is set rather than sleepq_catch_signals(). Note that it is the caller's responsibility to ensure that sleepq_catch_signals() is called if and only if this flag is passed to the preceeding sleepq_add(). Note that this also removes a sched_lock lock/unlock pair from sleepq_catch_signals(). It also ensures that for an interruptible sleep, TDF_SINTR is always set when TD_ON_SLEEPQ() is true.
470 lines
12 KiB
C
470 lines
12 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.
|
|
* 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
|
|
*/
|
|
|
|
#include <sys/cdefs.h>
|
|
__FBSDID("$FreeBSD$");
|
|
|
|
#include "opt_ktrace.h"
|
|
|
|
#include <sys/param.h>
|
|
#include <sys/systm.h>
|
|
#include <sys/condvar.h>
|
|
#include <sys/kdb.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/sched.h>
|
|
#include <sys/signalvar.h>
|
|
#include <sys/sleepqueue.h>
|
|
#include <sys/smp.h>
|
|
#include <sys/sx.h>
|
|
#include <sys/sysctl.h>
|
|
#include <sys/sysproto.h>
|
|
#include <sys/vmmeter.h>
|
|
#ifdef KTRACE
|
|
#include <sys/uio.h>
|
|
#include <sys/ktrace.h>
|
|
#endif
|
|
|
|
#include <machine/cpu.h>
|
|
|
|
static void synch_setup(void *dummy);
|
|
SYSINIT(synch_setup, SI_SUB_KICK_SCHEDULER, SI_ORDER_FIRST, synch_setup, NULL)
|
|
|
|
int hogticks;
|
|
int lbolt;
|
|
|
|
static struct callout loadav_callout;
|
|
static struct callout lbolt_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) */
|
|
};
|
|
|
|
/* kernel uses `FSCALE', userland (SHOULD) use kern.fscale */
|
|
static int fscale __unused = FSCALE;
|
|
SYSCTL_INT(_kern, OID_AUTO, fscale, CTLFLAG_RD, 0, FSCALE, "");
|
|
|
|
static void loadav(void *arg);
|
|
static void lboltcb(void *arg);
|
|
|
|
void
|
|
sleepinit(void)
|
|
{
|
|
|
|
hogticks = (hz / 10) * 2; /* Default only. */
|
|
init_sleepqueues();
|
|
}
|
|
|
|
/*
|
|
* 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 sleepqueue *sq;
|
|
struct thread *td;
|
|
struct proc *p;
|
|
int catch, rval, sig, flags;
|
|
WITNESS_SAVE_DECL(mtx);
|
|
|
|
td = curthread;
|
|
p = td->td_proc;
|
|
#ifdef KTRACE
|
|
if (KTRPOINT(td, KTR_CSW))
|
|
ktrcsw(1, 0);
|
|
#endif
|
|
WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, mtx == NULL ? NULL :
|
|
&mtx->mtx_object, "Sleeping on \"%s\"", wmesg);
|
|
KASSERT(timo != 0 || mtx_owned(&Giant) || mtx != NULL,
|
|
("sleeping without a mutex"));
|
|
KASSERT(p != NULL, ("msleep1"));
|
|
KASSERT(ident != NULL && TD_IS_RUNNING(td), ("msleep"));
|
|
|
|
if (cold) {
|
|
/*
|
|
* During autoconfiguration, just return;
|
|
* don't run any other threads or panic below,
|
|
* in case this is the idle thread and already asleep.
|
|
* XXX: this used to do "s = splhigh(); splx(safepri);
|
|
* splx(s);" to give interrupts a chance, but there is
|
|
* no way to give interrupts a chance now.
|
|
*/
|
|
if (mtx != NULL && priority & PDROP)
|
|
mtx_unlock(mtx);
|
|
return (0);
|
|
}
|
|
catch = priority & PCATCH;
|
|
rval = 0;
|
|
|
|
/*
|
|
* If we are already on a sleep queue, then remove us from that
|
|
* sleep queue first. We have to do this to handle recursive
|
|
* sleeps.
|
|
*/
|
|
if (TD_ON_SLEEPQ(td))
|
|
sleepq_remove(td, td->td_wchan);
|
|
|
|
sq = sleepq_lookup(ident);
|
|
if (catch) {
|
|
/*
|
|
* Don't bother sleeping if we are exiting and not the exiting
|
|
* thread or if our thread is marked as interrupted.
|
|
*/
|
|
mtx_lock_spin(&sched_lock);
|
|
rval = thread_sleep_check(td);
|
|
mtx_unlock_spin(&sched_lock);
|
|
if (rval != 0) {
|
|
sleepq_release(ident);
|
|
return (rval);
|
|
}
|
|
}
|
|
CTR5(KTR_PROC, "msleep: thread %p (pid %ld, %s) on %s (%p)",
|
|
(void *)td, (long)p->p_pid, p->p_comm, wmesg, ident);
|
|
|
|
DROP_GIANT();
|
|
if (mtx != NULL) {
|
|
mtx_assert(mtx, MA_OWNED | MA_NOTRECURSED);
|
|
WITNESS_SAVE(&mtx->mtx_object, mtx);
|
|
mtx_unlock(mtx);
|
|
}
|
|
|
|
/*
|
|
* 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, then td will no longer be on a sleep queue upon
|
|
* return from cursig().
|
|
*/
|
|
flags = SLEEPQ_MSLEEP;
|
|
if (catch)
|
|
flags |= SLEEPQ_INTERRUPTIBLE;
|
|
sleepq_add(sq, ident, mtx, wmesg, flags);
|
|
if (timo)
|
|
sleepq_set_timeout(ident, timo);
|
|
if (catch) {
|
|
sig = sleepq_catch_signals(ident);
|
|
} else
|
|
sig = 0;
|
|
|
|
/*
|
|
* Adjust this thread's priority.
|
|
*
|
|
* XXX: do we need to save priority in td_base_pri?
|
|
*/
|
|
mtx_lock_spin(&sched_lock);
|
|
sched_prio(td, priority & PRIMASK);
|
|
mtx_unlock_spin(&sched_lock);
|
|
|
|
if (timo && catch)
|
|
rval = sleepq_timedwait_sig(ident, sig != 0);
|
|
else if (timo)
|
|
rval = sleepq_timedwait(ident);
|
|
else if (catch)
|
|
rval = sleepq_wait_sig(ident);
|
|
else {
|
|
sleepq_wait(ident);
|
|
rval = 0;
|
|
}
|
|
if (rval == 0 && catch)
|
|
rval = sleepq_calc_signal_retval(sig);
|
|
#ifdef KTRACE
|
|
if (KTRPOINT(td, KTR_CSW))
|
|
ktrcsw(0, 0);
|
|
#endif
|
|
PICKUP_GIANT();
|
|
if (mtx != NULL && !(priority & PDROP)) {
|
|
mtx_lock(mtx);
|
|
WITNESS_RESTORE(&mtx->mtx_object, mtx);
|
|
}
|
|
return (rval);
|
|
}
|
|
|
|
/*
|
|
* Make all threads sleeping on the specified identifier runnable.
|
|
*/
|
|
void
|
|
wakeup(ident)
|
|
register void *ident;
|
|
{
|
|
|
|
sleepq_broadcast(ident, SLEEPQ_MSLEEP, -1);
|
|
}
|
|
|
|
/*
|
|
* Make a thread sleeping on the specified identifier runnable.
|
|
* May wake more than one thread if a target thread is currently
|
|
* swapped out.
|
|
*/
|
|
void
|
|
wakeup_one(ident)
|
|
register void *ident;
|
|
{
|
|
|
|
sleepq_signal(ident, SLEEPQ_MSLEEP, -1);
|
|
}
|
|
|
|
/*
|
|
* The machine independent parts of context switching.
|
|
*/
|
|
void
|
|
mi_switch(int flags, struct thread *newtd)
|
|
{
|
|
struct bintime new_switchtime;
|
|
struct thread *td;
|
|
struct proc *p;
|
|
|
|
mtx_assert(&sched_lock, MA_OWNED | MA_NOTRECURSED);
|
|
td = curthread; /* XXX */
|
|
p = td->td_proc; /* XXX */
|
|
KASSERT(!TD_ON_RUNQ(td), ("mi_switch: called by old code"));
|
|
#ifdef INVARIANTS
|
|
if (!TD_ON_LOCK(td) && !TD_IS_RUNNING(td))
|
|
mtx_assert(&Giant, MA_NOTOWNED);
|
|
#endif
|
|
KASSERT(td->td_critnest == 1 || (td->td_critnest == 2 &&
|
|
(td->td_pflags & TDP_OWEPREEMPT) != 0 && (flags & SW_INVOL) != 0 &&
|
|
newtd == NULL),
|
|
("mi_switch: switch in a critical section"));
|
|
KASSERT((flags & (SW_INVOL | SW_VOL)) != 0,
|
|
("mi_switch: switch must be voluntary or involuntary"));
|
|
KASSERT(newtd != curthread, ("mi_switch: preempting back to ourself"));
|
|
|
|
if (flags & SW_VOL)
|
|
p->p_stats->p_ru.ru_nvcsw++;
|
|
else
|
|
p->p_stats->p_ru.ru_nivcsw++;
|
|
|
|
/*
|
|
* 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));
|
|
|
|
td->td_generation++; /* bump preempt-detect counter */
|
|
|
|
/*
|
|
* Don't perform context switches from the debugger.
|
|
*/
|
|
if (kdb_active) {
|
|
mtx_unlock_spin(&sched_lock);
|
|
kdb_backtrace();
|
|
kdb_reenter();
|
|
panic("%s: did not reenter debugger", __func__);
|
|
}
|
|
|
|
/*
|
|
* Check if the process exceeds its cpu resource allocation. If
|
|
* over max, arrange to kill the process in ast().
|
|
*/
|
|
if (p->p_cpulimit != RLIM_INFINITY &&
|
|
p->p_runtime.sec > p->p_cpulimit) {
|
|
p->p_sflag |= PS_XCPU;
|
|
td->td_flags |= TDF_ASTPENDING;
|
|
}
|
|
|
|
/*
|
|
* Finish up stats for outgoing thread.
|
|
*/
|
|
cnt.v_swtch++;
|
|
PCPU_SET(switchtime, new_switchtime);
|
|
PCPU_SET(switchticks, ticks);
|
|
CTR4(KTR_PROC, "mi_switch: old thread %p (kse %p, pid %ld, %s)",
|
|
(void *)td, td->td_kse, (long)p->p_pid, p->p_comm);
|
|
if (td->td_proc->p_flag & P_SA)
|
|
thread_switchout(td);
|
|
sched_switch(td, newtd);
|
|
|
|
CTR4(KTR_PROC, "mi_switch: new thread %p (kse %p, pid %ld, %s)",
|
|
(void *)td, td->td_kse, (long)p->p_pid, p->p_comm);
|
|
|
|
/*
|
|
* If the last thread was exiting, finish cleaning it up.
|
|
*/
|
|
if ((td = PCPU_GET(deadthread))) {
|
|
PCPU_SET(deadthread, NULL);
|
|
thread_stash(td);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* 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;
|
|
|
|
p = td->td_proc;
|
|
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;
|
|
/* XXX: intentional fall-through ? */
|
|
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;
|
|
#ifndef SMP
|
|
/*
|
|
* XXX: Disabled on SMP due to a LOR between
|
|
* sched_lock and the sleepqueue chain locks.
|
|
*/
|
|
wakeup(&proc0);
|
|
#endif
|
|
}
|
|
} else
|
|
sched_wakeup(td);
|
|
}
|
|
|
|
/*
|
|
* 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;
|
|
|
|
nrun = sched_load();
|
|
avg = &averunnable;
|
|
|
|
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);
|
|
}
|
|
|
|
static void
|
|
lboltcb(void *arg)
|
|
{
|
|
wakeup(&lbolt);
|
|
callout_reset(&lbolt_callout, hz, lboltcb, NULL);
|
|
}
|
|
|
|
/* ARGSUSED */
|
|
static void
|
|
synch_setup(dummy)
|
|
void *dummy;
|
|
{
|
|
callout_init(&loadav_callout, CALLOUT_MPSAFE);
|
|
callout_init(&lbolt_callout, CALLOUT_MPSAFE);
|
|
|
|
/* Kick off timeout driven events by calling first time. */
|
|
loadav(NULL);
|
|
lboltcb(NULL);
|
|
}
|
|
|
|
/*
|
|
* General purpose yield system call
|
|
*/
|
|
int
|
|
yield(struct thread *td, struct yield_args *uap)
|
|
{
|
|
struct ksegrp *kg;
|
|
|
|
kg = td->td_ksegrp;
|
|
mtx_assert(&Giant, MA_NOTOWNED);
|
|
mtx_lock_spin(&sched_lock);
|
|
sched_prio(td, PRI_MAX_TIMESHARE);
|
|
mi_switch(SW_VOL, NULL);
|
|
mtx_unlock_spin(&sched_lock);
|
|
td->td_retval[0] = 0;
|
|
return (0);
|
|
}
|