xref: /freebsd/sys/kern/kern_idle.c (revision 61ba55bcf70f2340f9c943c9571113b3fd8eda69)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
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 #include <sys/param.h>
30 #include <sys/systm.h>
31 #include <sys/kernel.h>
32 #include <sys/kthread.h>
33 #include <sys/lock.h>
34 #include <sys/mutex.h>
35 #include <sys/proc.h>
36 #include <sys/resourcevar.h>
37 #include <sys/sched.h>
38 #include <sys/unistd.h>
39 #ifdef SMP
40 #include <sys/smp.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 /*
47  * Set up per-cpu idle process contexts.  The AP's shouldn't be running or
48  * accessing their idle processes at this point, so don't bother with
49  * locking.
50  */
51 static void
52 idle_setup(void *dummy)
53 {
54 #ifdef SMP
55 	struct pcpu *pc;
56 #endif
57 	struct proc *p;
58 	struct thread *td;
59 	int error;
60 
61 	p = NULL; /* start with no idle process */
62 #ifdef SMP
63 	STAILQ_FOREACH(pc, &cpuhead, pc_allcpu) {
64 #endif
65 #ifdef SMP
66 		error = kproc_kthread_add(sched_idletd, NULL, &p, &td,
67 		    RFSTOPPED | RFHIGHPID, 0, "idle", "idle: cpu%d", pc->pc_cpuid);
68 		pc->pc_idlethread = td;
69 #else
70 		error = kproc_kthread_add(sched_idletd, NULL, &p, &td,
71 		    RFSTOPPED | RFHIGHPID, 0, "idle", "idle");
72 		PCPU_SET(idlethread, td);
73 #endif
74 		if (error)
75 			panic("idle_setup: kproc_create error %d\n", error);
76 
77 		thread_lock(td);
78 		TD_SET_CAN_RUN(td);
79 		td->td_flags |= TDF_IDLETD | TDF_NOLOAD;
80 		sched_class(td, PRI_IDLE);
81 		sched_prio(td, PRI_MAX_IDLE);
82 		thread_unlock(td);
83 #ifdef SMP
84 	}
85 #endif
86 }
87