FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_idle.c
1 /*-
2 * Copyright (c) 2000, All rights reserved. See /usr/src/COPYRIGHT
3 *
4 * $FreeBSD: releng/5.1/sys/kern/kern_idle.c 114471 2003-05-02 00:33:12Z julian $
5 */
6
7 #include "opt_ktrace.h"
8
9 #include <sys/param.h>
10 #include <sys/systm.h>
11 #include <sys/kernel.h>
12 #include <sys/ktr.h>
13 #include <sys/kthread.h>
14 #include <sys/lock.h>
15 #include <sys/mutex.h>
16 #include <sys/pcpu.h>
17 #include <sys/proc.h>
18 #include <sys/resourcevar.h>
19 #include <sys/sched.h>
20 #include <sys/smp.h>
21 #include <sys/unistd.h>
22 #ifdef KTRACE
23 #include <sys/uio.h>
24 #include <sys/ktrace.h>
25 #endif
26
27 static void idle_setup(void *dummy);
28 SYSINIT(idle_setup, SI_SUB_SCHED_IDLE, SI_ORDER_FIRST, idle_setup, NULL)
29
30 static void idle_proc(void *dummy);
31
32 /*
33 * Setup per-cpu idle process contexts. The AP's shouldn't be running or
34 * accessing their idle processes at this point, so don't bother with
35 * locking.
36 */
37 static void
38 idle_setup(void *dummy)
39 {
40 #ifdef SMP
41 struct pcpu *pc;
42 #endif
43 struct proc *p;
44 struct thread *td;
45 int error;
46
47 #ifdef SMP
48 SLIST_FOREACH(pc, &cpuhead, pc_allcpu) {
49 error = kthread_create(idle_proc, NULL, &p,
50 RFSTOPPED | RFHIGHPID, 0, "idle: cpu%d", pc->pc_cpuid);
51 pc->pc_idlethread = FIRST_THREAD_IN_PROC(p);
52 if (pc->pc_curthread == NULL) {
53 pc->pc_curthread = pc->pc_idlethread;
54 pc->pc_idlethread->td_critnest = 0;
55 }
56 #else
57 error = kthread_create(idle_proc, NULL, &p,
58 RFSTOPPED | RFHIGHPID, 0, "idle");
59 PCPU_SET(idlethread, FIRST_THREAD_IN_PROC(p));
60 #endif
61 if (error)
62 panic("idle_setup: kthread_create error %d\n", error);
63
64 PROC_LOCK(p);
65 p->p_flag |= P_NOLOAD;
66 mtx_lock_spin(&sched_lock);
67 p->p_state = PRS_NORMAL;
68 td = FIRST_THREAD_IN_PROC(p);
69 td->td_state = TDS_CAN_RUN;
70 td->td_flags |= TDF_IDLETD;
71 mtx_unlock_spin(&sched_lock);
72 PROC_UNLOCK(p);
73 #ifdef SMP
74 }
75 #endif
76 }
77
78 /*
79 * idle process context
80 */
81 static void
82 idle_proc(void *dummy)
83 {
84 #ifdef DIAGNOSTIC
85 int count;
86 #endif
87 struct thread *td;
88 struct proc *p;
89
90 td = curthread;
91 p = td->td_proc;
92 for (;;) {
93 mtx_assert(&Giant, MA_NOTOWNED);
94
95 #ifdef DIAGNOSTIC
96 count = 0;
97
98 while (count >= 0 && sched_runnable() == 0) {
99 #else
100 while (sched_runnable() == 0) {
101 #endif
102 /*
103 * This is a good place to put things to be done in
104 * the background, including sanity checks.
105 */
106
107 #ifdef DIAGNOSTIC
108 if (count++ < 0)
109 CTR0(KTR_PROC, "idle_proc: timed out waiting"
110 " for a process");
111 #endif
112
113 #ifdef __i386__
114 cpu_idle();
115 #endif
116 }
117
118 mtx_lock_spin(&sched_lock);
119 p->p_stats->p_ru.ru_nvcsw++;
120 td->td_state = TDS_CAN_RUN;
121 mi_switch();
122 mtx_unlock_spin(&sched_lock);
123 }
124 }
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