kern_idle.c revision 76440 
1112177Stjr/*-
2103339Stjr * Copyright (c) 2000, All rights reserved.  See /usr/src/COPYRIGHT
3103339Stjr *
4103339Stjr * $FreeBSD: head/sys/kern/kern_idle.c 76440 2001-05-10 17:45:49Z jhb $
5103339Stjr */
6103339Stjr
7103339Stjr#include "opt_ktrace.h"
8103339Stjr
9103339Stjr#include <sys/param.h>
10103339Stjr#include <sys/systm.h>
11103339Stjr#include <sys/kernel.h>
12103339Stjr#include <sys/ktr.h>
13103339Stjr#include <sys/kthread.h>
14103339Stjr#include <sys/lock.h>
15103339Stjr#include <sys/mutex.h>
16103339Stjr#include <sys/pcpu.h>
17103339Stjr#include <sys/proc.h>
18103339Stjr#include <sys/resourcevar.h>
19103339Stjr#include <sys/smp.h>
20103339Stjr#include <sys/unistd.h>
21103339Stjr#if 0
22103339Stjr#include <vm/vm.h>
23103339Stjr#include <vm/vm_extern.h>
24103339Stjr#endif
25103339Stjr#ifdef KTRACE
26103339Stjr#include <sys/uio.h>
27112177Stjr#include <sys/ktrace.h>
28103339Stjr#endif
29103339Stjr
30103339Stjrstatic void idle_setup(void *dummy);
31112177StjrSYSINIT(idle_setup, SI_SUB_SCHED_IDLE, SI_ORDER_FIRST, idle_setup, NULL)
32112177Stjr
33112177Stjrstatic void idle_proc(void *dummy);
34115225Sru
35115225Sru/*
36115225Sru * Setup per-cpu idle process contexts.  The AP's shouldn't be running or
37115225Sru * accessing their idle processes at this point, so don't bother with
38103339Stjr * locking.
39103339Stjr */
40103339Stjrstatic void
41103339Stjridle_setup(void *dummy)
42112177Stjr{
43112177Stjr#ifdef SMP
44115225Sru	struct globaldata *gd;
45112177Stjr#endif
46103339Stjr	struct proc *p;
47103339Stjr	int error;
48103339Stjr
49103339Stjr#ifdef SMP
50112177Stjr	SLIST_FOREACH(gd, &cpuhead, gd_allcpu) {
51103339Stjr		error = kthread_create(idle_proc, NULL, &p,
52112177Stjr		    RFSTOPPED | RFHIGHPID, "idle: cpu%d", gd->gd_cpuid);
53112177Stjr		gd->gd_idleproc = p;
54112177Stjr		if (gd->gd_curproc == NULL)
55112177Stjr			gd->gd_curproc = p;
56103339Stjr#else
57112177Stjr		error = kthread_create(idle_proc, NULL, &p,
58112177Stjr		    RFSTOPPED | RFHIGHPID, "idle");
59115225Sru		PCPU_SET(idleproc, p);
60103339Stjr#endif
61103339Stjr		if (error)
62103339Stjr			panic("idle_setup: kthread_create error %d\n", error);
63103339Stjr
64112177Stjr		p->p_flag |= P_NOLOAD;
65115225Sru		p->p_stat = SRUN;
66103339Stjr#ifdef SMP
67103339Stjr	}
68112177Stjr#endif
69103339Stjr}
70112177Stjr
71112177Stjr/*
72112177Stjr * idle process context
73103339Stjr */
74static void
75idle_proc(void *dummy)
76{
77#ifdef DIAGNOSTIC
78	int count;
79#endif
80
81	for (;;) {
82		mtx_assert(&Giant, MA_NOTOWNED);
83
84#ifdef DIAGNOSTIC
85		count = 0;
86
87		while (count >= 0 && procrunnable() == 0) {
88#else
89		while (procrunnable() == 0) {
90#endif
91		/*
92		 * This is a good place to put things to be done in
93		 * the background, including sanity checks.
94		 */
95
96#ifdef DIAGNOSTIC
97			if (count++ < 0)
98				CTR0(KTR_PROC, "idle_proc: timed out waiting"
99				    " for a process");
100#endif
101
102#if 0
103			if (vm_page_zero_idle() != 0)
104				continue;
105#endif
106
107#ifdef __i386__
108			cpu_idle();
109#endif
110		}
111
112		mtx_lock_spin(&sched_lock);
113		curproc->p_stats->p_ru.ru_nvcsw++;
114		mi_switch();
115		mtx_unlock_spin(&sched_lock);
116	}
117}
118