kernel - Major signal path adjustments to fix races, tsleep race fixes, +more
[dragonfly.git] / sys / kern / kern_kthread.c
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1/*
2 * Copyright (c) 1999 Peter Wemm <peter@FreeBSD.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD: src/sys/kern/kern_kthread.c,v 1.5.2.3 2001/12/25 01:51:14 dillon Exp $
379210cb 27 * $DragonFly: src/sys/kern/kern_kthread.c,v 1.13 2006/12/18 20:41:01 dillon Exp $
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28 */
29
30#include <sys/param.h>
31#include <sys/systm.h>
32#include <sys/proc.h>
33#include <sys/kthread.h>
34#include <sys/ptrace.h>
35#include <sys/resourcevar.h>
36#include <sys/signalvar.h>
37#include <sys/unistd.h>
38#include <sys/wait.h>
39
40#include <machine/stdarg.h>
41
a3c18566 42static struct lwkt_token kpsus_token = LWKT_TOKEN_INITIALIZER(kpsus_token);
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43
44
984263bc 45/*
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46 * Create a kernel process/thread/whatever. It shares it's address space
47 * with proc0 - ie: kernel only. 5.x compatible.
48 *
cd8ab232 49 * All kthreads are created as MPSAFE threads.
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50 */
51int
52kthread_create(void (*func)(void *), void *arg,
be13c473 53 struct thread **tdp, const char *fmt, ...)
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54{
55 thread_t td;
56 __va_list ap;
57
fdce8919 58 td = lwkt_alloc_thread(NULL, LWKT_THREAD_STACK, -1, TDF_VERBOSE);
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59 if (tdp)
60 *tdp = td;
61 cpu_set_thread_handler(td, kthread_exit, func, arg);
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62
63 /*
64 * Set up arg0 for 'ps' etc
65 */
66 __va_start(ap, fmt);
379210cb 67 kvsnprintf(td->td_comm, sizeof(td->td_comm), fmt, ap);
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68 __va_end(ap);
69
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70 td->td_ucred = crhold(proc0.p_ucred);
71
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72 /*
73 * Schedule the thread to run
74 */
75 lwkt_schedule(td);
76 return 0;
77}
78
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79int
80kthread_create_cpu(void (*func)(void *), void *arg,
81 struct thread **tdp, int cpu, const char *fmt, ...)
82{
83 thread_t td;
84 __va_list ap;
85
fdce8919 86 td = lwkt_alloc_thread(NULL, LWKT_THREAD_STACK, cpu, TDF_VERBOSE);
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87 if (tdp)
88 *tdp = td;
89 cpu_set_thread_handler(td, kthread_exit, func, arg);
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90
91 /*
92 * Set up arg0 for 'ps' etc
93 */
94 __va_start(ap, fmt);
95 kvsnprintf(td->td_comm, sizeof(td->td_comm), fmt, ap);
96 __va_end(ap);
97
98 td->td_ucred = crhold(proc0.p_ucred);
99
100 /*
101 * Schedule the thread to run
102 */
103 lwkt_schedule(td);
104 return 0;
105}
106
d2d8515b 107#if 0
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108/*
109 * Same as kthread_create() but you can specify a custom stack size.
110 */
111int
112kthread_create_stk(void (*func)(void *), void *arg,
be13c473 113 struct thread **tdp, int stksize, const char *fmt, ...)
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114{
115 thread_t td;
116 __va_list ap;
117
fdce8919 118 td = lwkt_alloc_thread(NULL, stksize, -1, TDF_VERBOSE);
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119 if (tdp)
120 *tdp = td;
121 cpu_set_thread_handler(td, kthread_exit, func, arg);
cd8ab232 122
496907b0 123 __va_start(ap, fmt);
379210cb 124 kvsnprintf(td->td_comm, sizeof(td->td_comm), fmt, ap);
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125 __va_end(ap);
126
127 lwkt_schedule(td);
128 return 0;
129}
d2d8515b 130#endif
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131
132/*
133 * Destroy an LWKT thread. Warning! This function is not called when
134 * a process exits, cpu_proc_exit() directly calls cpu_thread_exit() and
135 * uses a different reaping mechanism.
136 *
137 * XXX duplicates lwkt_exit()
138 */
139void
140kthread_exit(void)
141{
142 lwkt_exit();
143}
144
496907b0 145/*
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146 * Start a kernel process. This is called after a fork() call in
147 * mi_startup() in the file kern/init_main.c.
148 *
149 * This function is used to start "internal" daemons and intended
150 * to be called from SYSINIT().
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151 *
152 * These threads are created MPSAFE.
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153 */
154void
77153250 155kproc_start(const void *udata)
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156{
157 const struct kproc_desc *kp = udata;
158 int error;
159
160 error = kthread_create((void (*)(void *))kp->func, NULL,
be13c473 161 kp->global_threadpp, kp->arg0);
26a0694b 162 lwkt_setpri(*kp->global_threadpp, TDPRI_KERN_DAEMON);
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163 if (error)
164 panic("kproc_start: %s: error %d", kp->arg0, error);
165}
166
167/*
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168 * Advise a kernel process to suspend (or resume) in its main loop.
169 * Participation is voluntary.
170 */
171int
bc6dffab 172suspend_kproc(struct thread *td, int timo)
984263bc 173{
0cfcada1 174 if (td->td_proc == NULL) {
cd8ab232 175 lwkt_gettoken(&kpsus_token);
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176 /* request thread pause */
177 atomic_set_int(&td->td_mpflags, TDF_MP_STOPREQ);
0cfcada1 178 wakeup(td);
4643740a 179 while (td->td_mpflags & TDF_MP_STOPREQ) {
377d4740 180 int error = tsleep(td, 0, "suspkp", timo);
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181 if (error == EWOULDBLOCK)
182 break;
183 }
4643740a 184 atomic_clear_int(&td->td_mpflags, TDF_MP_STOPREQ);
cd8ab232 185 lwkt_reltoken(&kpsus_token);
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186 return(0);
187 } else {
188 return(EINVAL); /* not a kernel thread */
189 }
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190}
191
192void
0cfcada1 193kproc_suspend_loop(void)
984263bc 194{
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195 struct thread *td = curthread;
196
4643740a 197 if (td->td_mpflags & TDF_MP_STOPREQ) {
cd8ab232 198 lwkt_gettoken(&kpsus_token);
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199 atomic_clear_int(&td->td_mpflags, TDF_MP_STOPREQ);
200 while ((td->td_mpflags & TDF_MP_WAKEREQ) == 0) {
0cfcada1 201 wakeup(td);
377d4740 202 tsleep(td, 0, "kpsusp", 0);
0cfcada1 203 }
4643740a 204 atomic_clear_int(&td->td_mpflags, TDF_MP_WAKEREQ);
0cfcada1 205 wakeup(td);
cd8ab232 206 lwkt_reltoken(&kpsus_token);
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207 }
208}
0cfcada1 209