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freebsd/sys/kern/kern_idle.c
John Baldwin 7e1f6dfe9d Modify the critical section API as follows:
- The MD functions critical_enter/exit are renamed to start with a cpu_
  prefix.
- MI wrapper functions critical_enter/exit maintain a per-thread nesting
  count and a per-thread critical section saved state set when entering
  a critical section while at nesting level 0 and restored when exiting
  to nesting level 0.  This moves the saved state out of spin mutexes so
  that interlocking spin mutexes works properly.
- Most low-level MD code that used critical_enter/exit now use
  cpu_critical_enter/exit.  MI code such as device drivers and spin
  mutexes use the MI wrappers.  Note that since the MI wrappers store
  the state in the current thread, they do not have any return values or
  arguments.
- mtx_intr_enable() is replaced with a constant CRITICAL_FORK which is
  assigned to curthread->td_savecrit during fork_exit().

Tested on:	i386, alpha
2001-12-18 00:27:18 +00:00

111 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/kernel.h>
#include <sys/ktr.h>
#include <sys/kthread.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/pcpu.h>
#include <sys/proc.h>
#include <sys/resourcevar.h>
#include <sys/smp.h>
#include <sys/unistd.h>
#ifdef KTRACE
#include <sys/uio.h>
#include <sys/ktrace.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. 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)
{
#ifdef SMP
struct pcpu *pc;
#endif
struct proc *p;
int error;
#ifdef SMP
SLIST_FOREACH(pc, &cpuhead, pc_allcpu) {
error = kthread_create(idle_proc, NULL, &p,
RFSTOPPED | RFHIGHPID, "idle: cpu%d", pc->pc_cpuid);
pc->pc_idlethread = &p->p_thread;
if (pc->pc_curthread == NULL) {
pc->pc_curthread = pc->pc_idlethread;
pc->pc_idlethread->td_critnest = 0;
}
#else
error = kthread_create(idle_proc, NULL, &p,
RFSTOPPED | RFHIGHPID, "idle");
PCPU_SET(idlethread, &p->p_thread);
#endif
if (error)
panic("idle_setup: kthread_create error %d\n", error);
p->p_flag |= P_NOLOAD;
p->p_stat = SRUN;
#ifdef SMP
}
#endif
}
/*
* 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
#ifdef __i386__
cpu_idle();
#endif
}
mtx_lock_spin(&sched_lock);
curproc->p_stats->p_ru.ru_nvcsw++;
mi_switch();
mtx_unlock_spin(&sched_lock);
}
}