freebsd-skq/sys/kern/kern_idle.c
jasone 769e0f974d Major update to the way synchronization is done in the kernel. Highlights
include:

* Mutual exclusion is used instead of spl*().  See mutex(9).  (Note: The
  alpha port is still in transition and currently uses both.)

* Per-CPU idle processes.

* Interrupts are run in their own separate kernel threads and can be
  preempted (i386 only).

Partially contributed by:	BSDi (BSD/OS)
Submissions by (at least):	cp, dfr, dillon, grog, jake, jhb, sheldonh
2000-09-07 01:33:02 +00:00

109 lines
2.1 KiB
C

/*-
* Copyright (c) 2000, All rights reserved. See /usr/src/COPYRIGHT
*
* $FreeBSD$
*/
#include "opt_ktrace.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/kernel.h>
#include <sys/ktr.h>
#include <sys/signalvar.h>
#include <sys/resourcevar.h>
#include <sys/vmmeter.h>
#include <sys/sysctl.h>
#include <sys/unistd.h>
#include <sys/kthread.h>
#include <sys/queue.h>
#include <vm/vm.h>
#include <vm/vm_extern.h>
#ifdef KTRACE
#include <sys/uio.h>
#include <sys/ktrace.h>
#endif
#include <machine/cpu.h>
#include <machine/ipl.h>
#include <machine/mutex.h>
#include <machine/smp.h>
#include <machine/globaldata.h>
#include <machine/globals.h>
#ifdef SMP_DEBUG
#include <sys/bus.h>
#include <i386/isa/icu.h>
#include <i386/isa/intr_machdep.h>
#endif
static void idle_setup(void *dummy);
SYSINIT(idle_setup, SI_SUB_SCHED_IDLE, SI_ORDER_FIRST, idle_setup, NULL)
static void idle_proc(void *dummy);
/*
* setup per-cpu idle process contexts
*/
static void
idle_setup(void *dummy)
{
struct globaldata *gd;
int error;
SLIST_FOREACH(gd, &cpuhead, gd_allcpu) {
#ifdef SMP
error = kthread_create(idle_proc, NULL, &gd->gd_idleproc,
RFSTOPPED|RFHIGHPID, "idle: cpu%d",
gd->gd_cpuid);
#else
error = kthread_create(idle_proc, NULL, &gd->gd_idleproc,
RFSTOPPED|RFHIGHPID, "idle");
#endif
if (error)
panic("idle_setup: kthread_create error %d\n", error);
gd->gd_idleproc->p_stat = SWAIT;
}
}
/*
* idle process context
*/
static void
idle_proc(void *dummy)
{
int count;
for (;;) {
/*
* Clear switchtime, which prevents the idle process's time
* from being counted.
switchtime.tv_usec = 0;
switchtime.tv_sec = 0;
*/
mtx_assert(&Giant, MA_NOTOWNED);
count = 0;
while (count >= 0 && procrunnable() == 0) {
/*
* This is a good place to put things to be done in
* the background, including sanity checks.
*/
if (count++ < 0)
CTR0(KTR_PROC, "idle_proc: timed out waiting"
" for a process");
}
mtx_enter(&sched_lock, MTX_SPIN);
idleproc->p_stat = SWAIT;
mi_switch();
mtx_exit(&sched_lock, MTX_SPIN);
spl0();
}
}