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 #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 static void idle_proc(void *dummy); 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 #ifdef SMP 64 SLIST_FOREACH(pc, &cpuhead, pc_allcpu) { 65 error = kthread_create(idle_proc, NULL, &p, 66 RFSTOPPED | RFHIGHPID, 0, "idle: cpu%d", pc->pc_cpuid); 67 pc->pc_idlethread = FIRST_THREAD_IN_PROC(p); 68 if (pc->pc_curthread == NULL) { 69 pc->pc_curthread = pc->pc_idlethread; 70 pc->pc_idlethread->td_critnest = 0; 71 } 72 #else 73 error = kthread_create(idle_proc, NULL, &p, 74 RFSTOPPED | RFHIGHPID, 0, "idle"); 75 PCPU_SET(idlethread, FIRST_THREAD_IN_PROC(p)); 76 #endif 77 if (error) 78 panic("idle_setup: kthread_create error %d\n", error); 79 80 PROC_LOCK(p); 81 p->p_flag |= P_NOLOAD; 82 mtx_lock_spin(&sched_lock); 83 td = FIRST_THREAD_IN_PROC(p); 84 TD_SET_CAN_RUN(td); 85 td->td_flags |= TDF_IDLETD; 86 sched_class(td->td_ksegrp, PRI_IDLE); 87 sched_prio(td, PRI_MAX_IDLE); 88 mtx_unlock_spin(&sched_lock); 89 PROC_UNLOCK(p); 90 #ifdef SMP 91 } 92 #endif 93 } 94 95 /* 96 * The actual idle process. 97 */ 98 static void 99 idle_proc(void *dummy) 100 { 101 struct proc *p; 102 struct thread *td; 103 #ifdef SMP 104 cpumask_t mycpu; 105 #endif 106 107 td = curthread; 108 p = td->td_proc; 109 #ifdef SMP 110 mycpu = PCPU_GET(cpumask); 111 mtx_lock_spin(&sched_lock); 112 idle_cpus_mask |= mycpu; 113 mtx_unlock_spin(&sched_lock); 114 #endif 115 for (;;) { 116 mtx_assert(&Giant, MA_NOTOWNED); 117 118 while (sched_runnable() == 0) 119 cpu_idle(); 120 121 mtx_lock_spin(&sched_lock); 122 #ifdef SMP 123 idle_cpus_mask &= ~mycpu; 124 #endif 125 mi_switch(SW_VOL, NULL); 126 #ifdef SMP 127 idle_cpus_mask |= mycpu; 128 #endif 129 mtx_unlock_spin(&sched_lock); 130 } 131 } 132