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 $ 27 * $DragonFly: src/sys/kern/kern_kthread.c,v 1.13 2006/12/18 20:41:01 dillon Exp $ 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 42 static struct lwkt_token kpsus_token = LWKT_TOKEN_INITIALIZER(kpsus_token); 43 44 45 /* 46 * Create a new lightweight kernel thread. 47 */ 48 static int 49 _kthread_create(void (*func)(void *), void *arg, 50 struct thread **tdp, int cpu, const char *fmt, __va_list ap) 51 { 52 thread_t td; 53 int flags = 0; 54 55 if (bootverbose) 56 atomic_set_int(&flags, TDF_VERBOSE); 57 58 td = lwkt_alloc_thread(NULL, LWKT_THREAD_STACK, cpu, flags); 59 if (tdp) 60 *tdp = td; 61 cpu_set_thread_handler(td, kthread_exit, func, arg); 62 63 /* 64 * Set up arg0 for 'ps' etc 65 */ 66 kvsnprintf(td->td_comm, sizeof(td->td_comm), fmt, ap); 67 68 td->td_ucred = crhold(proc0.p_ucred); 69 70 /* 71 * Schedule the thread to run 72 */ 73 lwkt_schedule(td); 74 75 return 0; 76 } 77 78 /* 79 * Creates a lwkt. No CPU preference. 80 */ 81 int 82 kthread_create(void (*func)(void *), void *arg, 83 struct thread **tdp, const char *fmt, ...) 84 { 85 __va_list ap; 86 int ret; 87 88 __va_start(ap, fmt); 89 ret = _kthread_create(func, arg, tdp, -1, fmt, ap); 90 __va_end(ap); 91 92 return ret; 93 } 94 95 /* 96 * Creates a lwkt and schedule it to run in a specific CPU. 97 * 98 */ 99 int 100 kthread_create_cpu(void (*func)(void *), void *arg, 101 struct thread **tdp, int cpu, const char *fmt, ...) 102 { 103 __va_list ap; 104 int ret; 105 106 __va_start(ap, fmt); 107 ret = _kthread_create(func, arg, tdp, cpu, fmt, ap); 108 __va_end(ap); 109 110 return ret; 111 } 112 113 #if 0 114 /* 115 * Same as kthread_create() but you can specify a custom stack size. 116 */ 117 int 118 kthread_create_stk(void (*func)(void *), void *arg, 119 struct thread **tdp, int stksize, const char *fmt, ...) 120 { 121 thread_t td; 122 __va_list ap; 123 124 td = lwkt_alloc_thread(NULL, stksize, -1, TDF_VERBOSE); 125 if (tdp) 126 *tdp = td; 127 cpu_set_thread_handler(td, kthread_exit, func, arg); 128 129 __va_start(ap, fmt); 130 kvsnprintf(td->td_comm, sizeof(td->td_comm), fmt, ap); 131 __va_end(ap); 132 133 lwkt_schedule(td); 134 return 0; 135 } 136 #endif 137 138 /* 139 * Destroy an LWKT thread. Warning! This function is not called when 140 * a process exits, cpu_proc_exit() directly calls cpu_thread_exit() and 141 * uses a different reaping mechanism. 142 * 143 * XXX duplicates lwkt_exit() 144 */ 145 void 146 kthread_exit(void) 147 { 148 lwkt_exit(); 149 } 150 151 /* 152 * Start a kernel process. This is called after a fork() call in 153 * mi_startup() in the file kern/init_main.c. 154 * 155 * This function is used to start "internal" daemons and intended 156 * to be called from SYSINIT(). 157 * 158 * These threads are created MPSAFE. 159 */ 160 void 161 kproc_start(const void *udata) 162 { 163 const struct kproc_desc *kp = udata; 164 int error; 165 166 error = kthread_create((void (*)(void *))kp->func, NULL, 167 kp->global_threadpp, kp->arg0); 168 lwkt_setpri(*kp->global_threadpp, TDPRI_KERN_DAEMON); 169 if (error) 170 panic("kproc_start: %s: error %d", kp->arg0, error); 171 } 172 173 /* 174 * Advise a kernel process to suspend (or resume) in its main loop. 175 * Participation is voluntary. 176 */ 177 int 178 suspend_kproc(struct thread *td, int timo) 179 { 180 if (td->td_proc == NULL) { 181 lwkt_gettoken(&kpsus_token); 182 /* request thread pause */ 183 atomic_set_int(&td->td_mpflags, TDF_MP_STOPREQ); 184 wakeup(td); 185 while (td->td_mpflags & TDF_MP_STOPREQ) { 186 int error = tsleep(td, 0, "suspkp", timo); 187 if (error == EWOULDBLOCK) 188 break; 189 } 190 atomic_clear_int(&td->td_mpflags, TDF_MP_STOPREQ); 191 lwkt_reltoken(&kpsus_token); 192 return(0); 193 } else { 194 return(EINVAL); /* not a kernel thread */ 195 } 196 } 197 198 void 199 kproc_suspend_loop(void) 200 { 201 struct thread *td = curthread; 202 203 if (td->td_mpflags & TDF_MP_STOPREQ) { 204 lwkt_gettoken(&kpsus_token); 205 atomic_clear_int(&td->td_mpflags, TDF_MP_STOPREQ); 206 while ((td->td_mpflags & TDF_MP_WAKEREQ) == 0) { 207 wakeup(td); 208 tsleep(td, 0, "kpsusp", 0); 209 } 210 atomic_clear_int(&td->td_mpflags, TDF_MP_WAKEREQ); 211 wakeup(td); 212 lwkt_reltoken(&kpsus_token); 213 } 214 } 215 216