sys/kern/kern_idle.c

   1 /*-
   2  * Copyright (c) 2000, All rights reserved.  See /usr/src/COPYRIGHT
   3  *
   4  * $FreeBSD$
   5  */
   6
   7 #include "opt_ktrace.h"
   8
   9 #include <sys/param.h>
  10 #include <sys/systm.h>
  11 #include <sys/proc.h>
  12 #include <sys/kernel.h>
  13 #include <sys/ktr.h>
  14 #include <sys/signalvar.h>
  15 #include <sys/resourcevar.h>
  16 #include <sys/vmmeter.h>
  17 #include <sys/sysctl.h>
  18 #include <sys/unistd.h>
  19 #include <sys/ipl.h>
  20 #include <sys/kthread.h>
  21 #include <sys/queue.h>
  22 #include <sys/eventhandler.h>
  23 #include <vm/vm.h>
  24 #include <vm/vm_extern.h>
  25 #ifdef KTRACE
  26 #include <sys/uio.h>
  27 #include <sys/ktrace.h>
  28 #endif
  29
  30 #include <machine/cpu.h>
  31 #include <machine/mutex.h>
  32 #include <machine/smp.h>
  33
  34 #include <machine/globaldata.h>
  35 #include <machine/globals.h>
  36
  37 #ifdef SMP_DEBUG
  38 #include <sys/bus.h>
  39 #include <i386/isa/icu.h>
  40 #include <i386/isa/intr_machdep.h>
  41 #endif
  42
  43 static void idle_setup(void *dummy);
  44 SYSINIT(idle_setup, SI_SUB_SCHED_IDLE, SI_ORDER_FIRST, idle_setup, NULL)
  45
  46 static void idle_proc(void *dummy);
  47
  48 EVENTHANDLER_FAST_DEFINE(idle_event, idle_eventhandler_t);
  49
  50 /*
  51  * setup per-cpu idle process contexts
  52  */
  53 static void
  54 idle_setup(void *dummy)
  55 {
  56         struct globaldata *gd;
  57         int error;
  58
  59         SLIST_FOREACH(gd, &cpuhead, gd_allcpu) {
  60 #ifdef SMP
  61                 error = kthread_create(idle_proc, NULL, &gd->gd_idleproc,
  62                                        RFSTOPPED|RFHIGHPID, "idle: cpu%d",
  63                                        gd->gd_cpuid);
  64 #else
  65                 error = kthread_create(idle_proc, NULL, &gd->gd_idleproc,
  66                                        RFSTOPPED|RFHIGHPID, "idle");
  67 #endif
  68                 if (error)
  69                         panic("idle_setup: kthread_create error %d\n", error);
  70
  71                 gd->gd_idleproc->p_flag |= P_NOLOAD;
  72                 gd->gd_idleproc->p_stat = SRUN;
  73         }
  74 }
  75
  76 /*
  77  * idle process context
  78  */
  79 static void
  80 idle_proc(void *dummy)
  81 {
  82         int count;
  83
  84         for (;;) {
  85                 mtx_assert(&Giant, MA_NOTOWNED);
  86
  87                 count = 0;
  88
  89                 while (count >= 0 && procrunnable() == 0) {
  90                 /*
  91                  * This is a good place to put things to be done in
  92                  * the background, including sanity checks.
  93                  */
  94
  95                         if (count++ < 0)
  96                                 CTR0(KTR_PROC, "idle_proc: timed out waiting"
  97                                     " for a process");
  98
  99                         /* call out to any cpu-becoming-idle events */
 100                         EVENTHANDLER_FAST_INVOKE(idle_event, count);
 101                 }
 102
 103                 mtx_enter(&sched_lock, MTX_SPIN);
 104                 mi_switch();
 105                 mtx_exit(&sched_lock, MTX_SPIN);
 106         }
 107 }