| 1 | /* $NetBSD: kern_idle.c,v 1.25 2012/01/29 22:55:40 rmind 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 1.25 2012/01/29 22:55:40 rmind Exp $" ); |
| 32 | |
| 33 | #include <sys/param.h> |
| 34 | #include <sys/cpu.h> |
| 35 | #include <sys/idle.h> |
| 36 | #include <sys/kthread.h> |
| 37 | #include <sys/lockdebug.h> |
| 38 | #include <sys/kmem.h> |
| 39 | #include <sys/proc.h> |
| 40 | #include <sys/atomic.h> |
| 41 | |
| 42 | #include <uvm/uvm.h> /* uvm_pageidlezero */ |
| 43 | #include <uvm/uvm_extern.h> |
| 44 | |
| 45 | void |
| 46 | idle_loop(void *dummy) |
| 47 | { |
| 48 | struct cpu_info *ci = curcpu(); |
| 49 | struct schedstate_percpu *spc; |
| 50 | struct lwp *l = curlwp; |
| 51 | |
| 52 | kcpuset_atomic_set(kcpuset_running, cpu_index(ci)); |
| 53 | ci->ci_data.cpu_onproc = l; |
| 54 | |
| 55 | /* Update start time for this thread. */ |
| 56 | lwp_lock(l); |
| 57 | binuptime(&l->l_stime); |
| 58 | lwp_unlock(l); |
| 59 | |
| 60 | /* |
| 61 | * Use spl0() here to ensure that we have the correct interrupt |
| 62 | * priority. This may be the first thread running on the CPU, |
| 63 | * in which case we took a dirtbag route to get here. |
| 64 | */ |
| 65 | spc = &ci->ci_schedstate; |
| 66 | (void)splsched(); |
| 67 | spc->spc_flags |= SPCF_RUNNING; |
| 68 | spl0(); |
| 69 | |
| 70 | KERNEL_UNLOCK_ALL(l, NULL); |
| 71 | l->l_stat = LSONPROC; |
| 72 | l->l_pflag |= LP_RUNNING; |
| 73 | for (;;) { |
| 74 | LOCKDEBUG_BARRIER(NULL, 0); |
| 75 | KASSERT((l->l_flag & LW_IDLE) != 0); |
| 76 | KASSERT(ci == curcpu()); |
| 77 | KASSERT(l == curlwp); |
| 78 | KASSERT(CURCPU_IDLE_P()); |
| 79 | KASSERT(l->l_priority == PRI_IDLE); |
| 80 | |
| 81 | sched_idle(); |
| 82 | if (!sched_curcpu_runnable_p()) { |
| 83 | if ((spc->spc_flags & SPCF_OFFLINE) == 0) { |
| 84 | uvm_pageidlezero(); |
| 85 | } |
| 86 | if (!sched_curcpu_runnable_p()) { |
| 87 | cpu_idle(); |
| 88 | if (!sched_curcpu_runnable_p() && |
| 89 | !ci->ci_want_resched) { |
| 90 | continue; |
| 91 | } |
| 92 | } |
| 93 | } |
| 94 | KASSERT(l->l_mutex == l->l_cpu->ci_schedstate.spc_lwplock); |
| 95 | lwp_lock(l); |
| 96 | mi_switch(l); |
| 97 | KASSERT(curlwp == l); |
| 98 | KASSERT(l->l_stat == LSONPROC); |
| 99 | } |
| 100 | } |
| 101 | |
| 102 | int |
| 103 | create_idle_lwp(struct cpu_info *ci) |
| 104 | { |
| 105 | lwp_t *l; |
| 106 | int error; |
| 107 | |
| 108 | KASSERT(ci->ci_data.cpu_idlelwp == NULL); |
| 109 | error = kthread_create(PRI_IDLE, KTHREAD_MPSAFE | KTHREAD_IDLE, |
| 110 | ci, idle_loop, NULL, &l, "idle/%u" , ci->ci_index); |
| 111 | if (error != 0) |
| 112 | panic("create_idle_lwp: error %d" , error); |
| 113 | lwp_lock(l); |
| 114 | l->l_flag |= LW_IDLE; |
| 115 | lwp_unlock(l); |
| 116 | l->l_cpu = ci; |
| 117 | ci->ci_data.cpu_idlelwp = l; |
| 118 | |
| 119 | return error; |
| 120 | } |
| 121 | |