1 /* $NetBSD: kern_idle.c,v 1.4 2007/07/21 19:06:22 ad Exp $ */ 2 3 /*- 4 * Copyright (c)2002, 2006, 2007 YAMAMOTO Takashi, 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #include <sys/cdefs.h> 30 31 __KERNEL_RCSID(0, "$NetBSD: kern_idle.c,v 1.4 2007/07/21 19:06:22 ad Exp $"); 32 33 #include <sys/param.h> 34 #include <sys/cpu.h> 35 #include <sys/idle.h> 36 #include <sys/lwp.h> 37 #include <sys/lockdebug.h> 38 #include <sys/kmem.h> 39 #include <sys/proc.h> 40 41 #include <uvm/uvm.h> 42 #include <uvm/uvm_extern.h> 43 44 #define PIDLELWP (MAXPRI + 1) /* lowest priority */ 45 46 void 47 idle_loop(void *dummy) 48 { 49 #if defined(DIAGNOSTIC) 50 struct cpu_info *ci = curcpu(); 51 #endif /* defined(DIAGNOSTIC) */ 52 struct lwp *l = curlwp; 53 54 KERNEL_UNLOCK_ALL(l, NULL); 55 l->l_usrpri = PIDLELWP; 56 l->l_priority = l->l_usrpri; 57 l->l_stat = LSONPROC; 58 while (1 /* CONSTCOND */) { 59 KERNEL_LOCK_ASSERT_UNLOCKED(); 60 LOCKDEBUG_BARRIER(NULL, 0); 61 KASSERT((l->l_flag & LW_IDLE) != 0); 62 KASSERT(ci == curcpu()); 63 KASSERT(l == curlwp); 64 KASSERT(CURCPU_IDLE_P()); 65 KASSERT(l->l_usrpri == PIDLELWP); 66 67 if (uvm.page_idle_zero) { 68 if (sched_curcpu_runnable_p()) { 69 goto schedule; 70 } 71 uvm_pageidlezero(); 72 } 73 if (!sched_curcpu_runnable_p()) { 74 cpu_idle(); 75 if (!sched_curcpu_runnable_p()) { 76 continue; 77 } 78 } 79 schedule: 80 KASSERT(l->l_mutex == &l->l_cpu->ci_schedstate.spc_lwplock); 81 lwp_lock(l); 82 mi_switch(l); 83 KASSERT(curlwp == l); 84 KASSERT(l->l_stat == LSONPROC); 85 } 86 } 87 88 int 89 create_idle_lwp(struct cpu_info *ci) 90 { 91 struct proc *p = &proc0; 92 struct lwp *l; 93 char *name; 94 vaddr_t uaddr; 95 bool inmem; 96 cpuid_t cpuid; 97 int error; 98 99 KASSERT(ci->ci_data.cpu_idlelwp == NULL); 100 inmem = uvm_uarea_alloc(&uaddr); 101 if (uaddr == 0) { 102 return ENOMEM; 103 } 104 error = newlwp(&lwp0, p, uaddr, inmem, 0, NULL, 0, idle_loop, NULL, &l); 105 if (error != 0) { 106 panic("create_idle_lwp: newlwp failed"); 107 } 108 uvm_lwp_hold(l); 109 l->l_flag |= (LW_IDLE | LW_BOUND); 110 l->l_cpu = ci; 111 l->l_mutex = &ci->ci_schedstate.spc_lwplock; 112 ci->ci_data.cpu_idlelwp = l; 113 name = kmem_alloc(MAXCOMLEN, KM_NOSLEEP); 114 if (name != NULL) { 115 #ifdef MULTIPROCESSOR /* XXX should be mandatory */ 116 cpuid = ci->ci_cpuid; 117 #else 118 cpuid = 0; 119 #endif 120 snprintf(name, MAXCOMLEN, "idle/%d", (int)cpuid); 121 lwp_lock(l); 122 l->l_name = name; 123 lwp_unlock(l); 124 } 125 return error; 126 } 127