1 /*- 2 * Copyright (C) 2000-2004 The FreeBSD Project. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 13 * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND 14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16 * ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE 17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23 * SUCH DAMAGE. 24 */ 25 26 #include <sys/cdefs.h> 27 __FBSDID("$FreeBSD$"); 28 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 40 static void idle_setup(void *dummy); 41 SYSINIT(idle_setup, SI_SUB_SCHED_IDLE, SI_ORDER_FIRST, idle_setup, NULL) 42 43 static void idle_proc(void *dummy); 44 45 /* 46 * Set up per-cpu idle process contexts. The AP's shouldn't be running or 47 * accessing their idle processes at this point, so don't bother with 48 * locking. 49 */ 50 static void 51 idle_setup(void *dummy) 52 { 53 #ifdef SMP 54 struct pcpu *pc; 55 #endif 56 struct proc *p; 57 struct thread *td; 58 int error; 59 60 #ifdef SMP 61 SLIST_FOREACH(pc, &cpuhead, pc_allcpu) { 62 error = kthread_create(idle_proc, NULL, &p, 63 RFSTOPPED | RFHIGHPID, 0, "idle: cpu%d", pc->pc_cpuid); 64 pc->pc_idlethread = FIRST_THREAD_IN_PROC(p); 65 if (pc->pc_curthread == NULL) { 66 pc->pc_curthread = pc->pc_idlethread; 67 pc->pc_idlethread->td_critnest = 0; 68 } 69 #else 70 error = kthread_create(idle_proc, NULL, &p, 71 RFSTOPPED | RFHIGHPID, 0, "idle"); 72 PCPU_SET(idlethread, FIRST_THREAD_IN_PROC(p)); 73 #endif 74 if (error) 75 panic("idle_setup: kthread_create error %d\n", error); 76 77 PROC_LOCK(p); 78 p->p_flag |= P_NOLOAD; 79 mtx_lock_spin(&sched_lock); 80 td = FIRST_THREAD_IN_PROC(p); 81 TD_SET_CAN_RUN(td); 82 td->td_flags |= TDF_IDLETD; 83 td->td_priority = PRI_MAX_IDLE; 84 mtx_unlock_spin(&sched_lock); 85 PROC_UNLOCK(p); 86 #ifdef SMP 87 } 88 #endif 89 } 90 91 /* 92 * The actual idle process. 93 */ 94 static void 95 idle_proc(void *dummy) 96 { 97 struct proc *p; 98 struct thread *td; 99 100 td = curthread; 101 p = td->td_proc; 102 for (;;) { 103 mtx_assert(&Giant, MA_NOTOWNED); 104 105 while (sched_runnable() == 0) 106 cpu_idle(); 107 108 mtx_lock_spin(&sched_lock); 109 mi_switch(SW_VOL, NULL); 110 mtx_unlock_spin(&sched_lock); 111 } 112 } 113