xref: /freebsd/sys/kern/kern_idle.c (revision dd41de95a84d979615a2ef11df6850622bf6184e)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (C) 2000-2004 The FreeBSD Project. All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18  * ARE DISCLAIMED.  IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25  * SUCH DAMAGE.
26  */
27 
28 #include <sys/cdefs.h>
29 __FBSDID("$FreeBSD$");
30 
31 #include <sys/param.h>
32 #include <sys/systm.h>
33 #include <sys/kernel.h>
34 #include <sys/kthread.h>
35 #include <sys/lock.h>
36 #include <sys/mutex.h>
37 #include <sys/proc.h>
38 #include <sys/resourcevar.h>
39 #include <sys/sched.h>
40 #include <sys/unistd.h>
41 #ifdef SMP
42 #include <sys/smp.h>
43 #endif
44 
45 static void idle_setup(void *dummy);
46 SYSINIT(idle_setup, SI_SUB_SCHED_IDLE, SI_ORDER_FIRST, idle_setup, NULL);
47 
48 /*
49  * Set up per-cpu idle process contexts.  The AP's shouldn't be running or
50  * accessing their idle processes at this point, so don't bother with
51  * locking.
52  */
53 static void
54 idle_setup(void *dummy)
55 {
56 #ifdef SMP
57 	struct pcpu *pc;
58 #endif
59 	struct proc *p;
60 	struct thread *td;
61 	int error;
62 
63 	p = NULL; /* start with no idle process */
64 #ifdef SMP
65 	STAILQ_FOREACH(pc, &cpuhead, pc_allcpu) {
66 #endif
67 #ifdef SMP
68 		error = kproc_kthread_add(sched_idletd, NULL, &p, &td,
69 		    RFSTOPPED | RFHIGHPID, 0, "idle", "idle: cpu%d", pc->pc_cpuid);
70 		pc->pc_idlethread = td;
71 #else
72 		error = kproc_kthread_add(sched_idletd, NULL, &p, &td,
73 		    RFSTOPPED | RFHIGHPID, 0, "idle", "idle");
74 		PCPU_SET(idlethread, td);
75 #endif
76 		if (error)
77 			panic("idle_setup: kproc_create error %d\n", error);
78 
79 		thread_lock(td);
80 		TD_SET_CAN_RUN(td);
81 		td->td_flags |= TDF_IDLETD | TDF_NOLOAD;
82 		sched_class(td, PRI_IDLE);
83 		sched_prio(td, PRI_MAX_IDLE);
84 		thread_unlock(td);
85 #ifdef SMP
86 	}
87 #endif
88 }
89