FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_idle.c
1 /*-
2 * Copyright (c) 2000, All rights reserved. See /usr/src/COPYRIGHT
3 *
4 */
5
6 #include <sys/cdefs.h>
7 __FBSDID("$FreeBSD: releng/5.2/sys/kern/kern_idle.c 121238 2003-10-19 02:43:57Z peter $");
8
9 #include <sys/param.h>
10 #include <sys/systm.h>
11 #include <sys/kernel.h>
12 #include <sys/kthread.h>
13 #include <sys/lock.h>
14 #include <sys/mutex.h>
15 #include <sys/proc.h>
16 #include <sys/resourcevar.h>
17 #include <sys/sched.h>
18 #include <sys/unistd.h>
19
20 static void idle_setup(void *dummy);
21 SYSINIT(idle_setup, SI_SUB_SCHED_IDLE, SI_ORDER_FIRST, idle_setup, NULL)
22
23 static void idle_proc(void *dummy);
24
25 /*
26 * Set up per-cpu idle process contexts. The AP's shouldn't be running or
27 * accessing their idle processes at this point, so don't bother with
28 * locking.
29 */
30 static void
31 idle_setup(void *dummy)
32 {
33 #ifdef SMP
34 struct pcpu *pc;
35 #endif
36 struct proc *p;
37 struct thread *td;
38 int error;
39
40 #ifdef SMP
41 SLIST_FOREACH(pc, &cpuhead, pc_allcpu) {
42 error = kthread_create(idle_proc, NULL, &p,
43 RFSTOPPED | RFHIGHPID, 0, "idle: cpu%d", pc->pc_cpuid);
44 pc->pc_idlethread = FIRST_THREAD_IN_PROC(p);
45 if (pc->pc_curthread == NULL) {
46 pc->pc_curthread = pc->pc_idlethread;
47 pc->pc_idlethread->td_critnest = 0;
48 }
49 #else
50 error = kthread_create(idle_proc, NULL, &p,
51 RFSTOPPED | RFHIGHPID, 0, "idle");
52 PCPU_SET(idlethread, FIRST_THREAD_IN_PROC(p));
53 #endif
54 if (error)
55 panic("idle_setup: kthread_create error %d\n", error);
56
57 PROC_LOCK(p);
58 p->p_flag |= P_NOLOAD;
59 mtx_lock_spin(&sched_lock);
60 p->p_state = PRS_NORMAL;
61 td = FIRST_THREAD_IN_PROC(p);
62 td->td_state = TDS_CAN_RUN;
63 td->td_flags |= TDF_IDLETD;
64 mtx_unlock_spin(&sched_lock);
65 PROC_UNLOCK(p);
66 #ifdef SMP
67 }
68 #endif
69 }
70
71 /*
72 * The actual idle process.
73 */
74 static void
75 idle_proc(void *dummy)
76 {
77 struct proc *p;
78 struct thread *td;
79
80 td = curthread;
81 p = td->td_proc;
82 for (;;) {
83 mtx_assert(&Giant, MA_NOTOWNED);
84
85 while (sched_runnable() == 0)
86 cpu_idle();
87
88 mtx_lock_spin(&sched_lock);
89 td->td_state = TDS_CAN_RUN;
90 p->p_stats->p_ru.ru_nvcsw++;
91 mi_switch();
92 mtx_unlock_spin(&sched_lock);
93 }
94 }
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