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 | |