freebsd-dev/sys/kern/kern_idle.c
John Baldwin 7ecfc090c0 - Point out that we don't lock anything during the idle setup because
only the boot processor should be running in the comments.
- Initialize curproc to point to each CPU's respective idleproc if their
  curproc is NULL.
- Keep track of the number of context switches performed by idleproc.
2001-02-09 14:59:43 +00:00

118 lines
2.3 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/ipl.h>
#include <sys/kthread.h>
#include <sys/mutex.h>
#include <sys/queue.h>
#include <sys/eventhandler.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/md_var.h>
#include <machine/smp.h>
#include <machine/globaldata.h>
#include <machine/globals.h>
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. The AP's shouldn't be running or
* accessing their idle processes at this point, so don't bother with
* locking.
*/
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_flag |= P_NOLOAD;
gd->gd_idleproc->p_stat = SRUN;
if (gd->gd_curproc == NULL)
gd->gd_curproc = gd->gd_idleproc;
}
}
/*
* idle process context
*/
static void
idle_proc(void *dummy)
{
#ifdef DIAGNOSTIC
int count;
#endif
for (;;) {
mtx_assert(&Giant, MA_NOTOWNED);
#ifdef DIAGNOSTIC
count = 0;
while (count >= 0 && procrunnable() == 0) {
#else
while (procrunnable() == 0) {
#endif
/*
* This is a good place to put things to be done in
* the background, including sanity checks.
*/
#ifdef DIAGNOSTIC
if (count++ < 0)
CTR0(KTR_PROC, "idle_proc: timed out waiting"
" for a process");
#endif
if (vm_page_zero_idle() != 0)
continue;
#ifdef __i386__
cpu_idle();
#endif
}
mtx_lock_spin(&sched_lock);
curproc->p_stats->p_ru.ru_nvcsw++;
mi_switch();
mtx_unlock_spin(&sched_lock);
}
}