The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]

FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_kthread.c

Version: -  FREEBSD  -  FREEBSD-12-STABLE  -  FREEBSD-12-0  -  FREEBSD-11-STABLE  -  FREEBSD-11-2  -  FREEBSD-11-1  -  FREEBSD-11-0  -  FREEBSD-10-STABLE  -  FREEBSD-10-4  -  FREEBSD-10-3  -  FREEBSD-10-2  -  FREEBSD-10-1  -  FREEBSD-10-0  -  FREEBSD-9-STABLE  -  FREEBSD-9-3  -  FREEBSD-9-2  -  FREEBSD-9-1  -  FREEBSD-9-0  -  FREEBSD-8-STABLE  -  FREEBSD-8-4  -  FREEBSD-8-3  -  FREEBSD-8-2  -  FREEBSD-8-1  -  FREEBSD-8-0  -  FREEBSD-7-STABLE  -  FREEBSD-7-4  -  FREEBSD-7-3  -  FREEBSD-7-2  -  FREEBSD-7-1  -  FREEBSD-7-0  -  FREEBSD-6-STABLE  -  FREEBSD-6-4  -  FREEBSD-6-3  -  FREEBSD-6-2  -  FREEBSD-6-1  -  FREEBSD-6-0  -  FREEBSD-5-STABLE  -  FREEBSD-5-5  -  FREEBSD-5-4  -  FREEBSD-5-3  -  FREEBSD-5-2  -  FREEBSD-5-1  -  FREEBSD-5-0  -  FREEBSD-4-STABLE  -  FREEBSD-3-STABLE  -  FREEBSD22  -  linux-2.6  -  linux-2.4.22  -  MK83  -  MK84  -  PLAN9  -  DFBSD  -  NETBSD  -  NETBSD5  -  NETBSD4  -  NETBSD3  -  NETBSD20  -  OPENBSD  -  xnu-517  -  xnu-792  -  xnu-792.6.70  -  xnu-1228  -  xnu-1456.1.26  -  xnu-1699.24.8  -  xnu-2050.18.24  -  OPENSOLARIS  -  minix-3-1-1 
SearchContext: -  none  -  3  -  10 

    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 
   27 #include <sys/cdefs.h>
   28 __FBSDID("$FreeBSD: releng/8.3/sys/kern/kern_kthread.c 218355 2011-02-05 22:57:14Z kib $");
   29 
   30 #include <sys/param.h>
   31 #include <sys/systm.h>
   32 #include <sys/kthread.h>
   33 #include <sys/lock.h>
   34 #include <sys/mutex.h>
   35 #include <sys/proc.h>
   36 #include <sys/resourcevar.h>
   37 #include <sys/signalvar.h>
   38 #include <sys/sx.h>
   39 #include <sys/unistd.h>
   40 #include <sys/wait.h>
   41 #include <sys/sched.h>
   42 #include <vm/vm.h>
   43 #include <vm/vm_extern.h>
   44 
   45 #include <machine/stdarg.h>
   46 
   47 /*
   48  * Start a kernel process.  This is called after a fork() call in
   49  * mi_startup() in the file kern/init_main.c.
   50  *
   51  * This function is used to start "internal" daemons and intended
   52  * to be called from SYSINIT().
   53  */
   54 void
   55 kproc_start(udata)
   56         const void *udata;
   57 {
   58         const struct kproc_desc *kp = udata;
   59         int error;
   60 
   61         error = kproc_create((void (*)(void *))kp->func, NULL,
   62                     kp->global_procpp, 0, 0, "%s", kp->arg0);
   63         if (error)
   64                 panic("kproc_start: %s: error %d", kp->arg0, error);
   65 }
   66 
   67 /*
   68  * Create a kernel process/thread/whatever.  It shares its address space
   69  * with proc0 - ie: kernel only.
   70  *
   71  * func is the function to start.
   72  * arg is the parameter to pass to function on first startup.
   73  * newpp is the return value pointing to the thread's struct proc.
   74  * flags are flags to fork1 (in unistd.h)
   75  * fmt and following will be *printf'd into (*newpp)->p_comm (for ps, etc.).
   76  */
   77 int
   78 kproc_create(void (*func)(void *), void *arg,
   79     struct proc **newpp, int flags, int pages, const char *fmt, ...)
   80 {
   81         int error;
   82         va_list ap;
   83         struct thread *td;
   84         struct proc *p2;
   85 
   86         if (!proc0.p_stats)
   87                 panic("kproc_create called too soon");
   88 
   89         error = fork1(&thread0, RFMEM | RFFDG | RFPROC | RFSTOPPED | flags,
   90             pages, &p2);
   91         if (error)
   92                 return error;
   93 
   94         /* save a global descriptor, if desired */
   95         if (newpp != NULL)
   96                 *newpp = p2;
   97 
   98         /* this is a non-swapped system process */
   99         PROC_LOCK(p2);
  100         td = FIRST_THREAD_IN_PROC(p2);
  101         p2->p_flag |= P_SYSTEM | P_KTHREAD;
  102         td->td_pflags |= TDP_KTHREAD;
  103         mtx_lock(&p2->p_sigacts->ps_mtx);
  104         p2->p_sigacts->ps_flag |= PS_NOCLDWAIT;
  105         mtx_unlock(&p2->p_sigacts->ps_mtx);
  106         PROC_UNLOCK(p2);
  107 
  108         /* set up arg0 for 'ps', et al */
  109         va_start(ap, fmt);
  110         vsnprintf(p2->p_comm, sizeof(p2->p_comm), fmt, ap);
  111         va_end(ap);
  112         /* set up arg0 for 'ps', et al */
  113         va_start(ap, fmt);
  114         vsnprintf(td->td_name, sizeof(td->td_name), fmt, ap);
  115         va_end(ap);
  116 
  117         /* call the processes' main()... */
  118         cpu_set_fork_handler(td, func, arg);
  119         thread_lock(td);
  120         TD_SET_CAN_RUN(td);
  121         sched_prio(td, PVM);
  122         sched_user_prio(td, PUSER);
  123 
  124         /* Delay putting it on the run queue until now. */
  125         if (!(flags & RFSTOPPED))
  126                 sched_add(td, SRQ_BORING); 
  127         thread_unlock(td);
  128 
  129         return 0;
  130 }
  131 
  132 void
  133 kproc_exit(int ecode)
  134 {
  135         struct thread *td;
  136         struct proc *p;
  137 
  138         td = curthread;
  139         p = td->td_proc;
  140 
  141         /*
  142          * Reparent curthread from proc0 to init so that the zombie
  143          * is harvested.
  144          */
  145         sx_xlock(&proctree_lock);
  146         PROC_LOCK(p);
  147         proc_reparent(p, initproc);
  148         PROC_UNLOCK(p);
  149         sx_xunlock(&proctree_lock);
  150 
  151         /*
  152          * Wakeup anyone waiting for us to exit.
  153          */
  154         wakeup(p);
  155 
  156         /* Buh-bye! */
  157         exit1(td, W_EXITCODE(ecode, 0));
  158 }
  159 
  160 /*
  161  * Advise a kernel process to suspend (or resume) in its main loop.
  162  * Participation is voluntary.
  163  */
  164 int
  165 kproc_suspend(struct proc *p, int timo)
  166 {
  167         /*
  168          * Make sure this is indeed a system process and we can safely
  169          * use the p_siglist field.
  170          */
  171         PROC_LOCK(p);
  172         if ((p->p_flag & P_KTHREAD) == 0) {
  173                 PROC_UNLOCK(p);
  174                 return (EINVAL);
  175         }
  176         SIGADDSET(p->p_siglist, SIGSTOP);
  177         wakeup(p);
  178         return msleep(&p->p_siglist, &p->p_mtx, PPAUSE | PDROP, "suspkp", timo);
  179 }
  180 
  181 int
  182 kproc_resume(struct proc *p)
  183 {
  184         /*
  185          * Make sure this is indeed a system process and we can safely
  186          * use the p_siglist field.
  187          */
  188         PROC_LOCK(p);
  189         if ((p->p_flag & P_KTHREAD) == 0) {
  190                 PROC_UNLOCK(p);
  191                 return (EINVAL);
  192         }
  193         SIGDELSET(p->p_siglist, SIGSTOP);
  194         PROC_UNLOCK(p);
  195         wakeup(&p->p_siglist);
  196         return (0);
  197 }
  198 
  199 void
  200 kproc_suspend_check(struct proc *p)
  201 {
  202         PROC_LOCK(p);
  203         while (SIGISMEMBER(p->p_siglist, SIGSTOP)) {
  204                 wakeup(&p->p_siglist);
  205                 msleep(&p->p_siglist, &p->p_mtx, PPAUSE, "kpsusp", 0);
  206         }
  207         PROC_UNLOCK(p);
  208 }
  209 
  210 
  211 /*
  212  * Start a kernel thread.  
  213  *
  214  * This function is used to start "internal" daemons and intended
  215  * to be called from SYSINIT().
  216  */
  217 
  218 void
  219 kthread_start(udata)
  220         const void *udata;
  221 {
  222         const struct kthread_desc       *kp = udata;
  223         int error;
  224 
  225         error = kthread_add((void (*)(void *))kp->func, NULL,
  226                     NULL, kp->global_threadpp, 0, 0, "%s", kp->arg0);
  227         if (error)
  228                 panic("kthread_start: %s: error %d", kp->arg0, error);
  229 }
  230 
  231 /*
  232  * Create a kernel thread.  It shares its address space
  233  * with proc0 - ie: kernel only.
  234  *
  235  * func is the function to start.
  236  * arg is the parameter to pass to function on first startup.
  237  * newtdp is the return value pointing to the thread's struct thread.
  238  *  ** XXX fix this --> flags are flags to fork1 (in unistd.h) 
  239  * fmt and following will be *printf'd into (*newtd)->td_name (for ps, etc.).
  240  */
  241 int
  242 kthread_add(void (*func)(void *), void *arg, struct proc *p,
  243     struct thread **newtdp, int flags, int pages, const char *fmt, ...)
  244 {
  245         va_list ap;
  246         struct thread *newtd, *oldtd;
  247 
  248         if (!proc0.p_stats)
  249                 panic("kthread_add called too soon");
  250 
  251         /* If no process supplied, put it on proc0 */
  252         if (p == NULL) {
  253                 p = &proc0;
  254                 oldtd = &thread0;
  255         } else {
  256                 oldtd = FIRST_THREAD_IN_PROC(p);
  257         }
  258 
  259         /* Initialize our new td  */
  260         newtd = thread_alloc(pages);
  261         if (newtd == NULL)
  262                 return (ENOMEM);
  263 
  264         bzero(&newtd->td_startzero,
  265             __rangeof(struct thread, td_startzero, td_endzero));
  266         bzero(&newtd->td_rux, sizeof(newtd->td_rux));
  267         newtd->td_map_def_user = NULL;
  268         newtd->td_dbg_forked = 0;
  269 /* XXX check if we should zero. */
  270         bcopy(&oldtd->td_startcopy, &newtd->td_startcopy,
  271             __rangeof(struct thread, td_startcopy, td_endcopy));
  272 
  273         /* set up arg0 for 'ps', et al */
  274         va_start(ap, fmt);
  275         vsnprintf(newtd->td_name, sizeof(newtd->td_name), fmt, ap);
  276         va_end(ap);
  277 
  278         newtd->td_proc = p;  /* needed for cpu_set_upcall */
  279 
  280         /* XXX optimise this probably? */
  281         /* On x86 (and probably the others too) it is way too full of junk */
  282         /* Needs a better name */
  283         cpu_set_upcall(newtd, oldtd);
  284         /* put the designated function(arg) as the resume context */
  285         cpu_set_fork_handler(newtd, func, arg);
  286 
  287         newtd->td_pflags |= TDP_KTHREAD;
  288         newtd->td_ucred = crhold(p->p_ucred);
  289 
  290         /* this code almost the same as create_thread() in kern_thr.c */
  291         PROC_LOCK(p);
  292         p->p_flag |= P_HADTHREADS;
  293         newtd->td_sigmask = oldtd->td_sigmask; /* XXX dubious */
  294         thread_link(newtd, p);
  295         thread_lock(oldtd);
  296         /* let the scheduler know about these things. */
  297         sched_fork_thread(oldtd, newtd);
  298         TD_SET_CAN_RUN(newtd);
  299         thread_unlock(oldtd);
  300         PROC_UNLOCK(p);
  301 
  302 
  303         /* Delay putting it on the run queue until now. */
  304         if (!(flags & RFSTOPPED)) {
  305                 thread_lock(newtd);
  306                 sched_add(newtd, SRQ_BORING); 
  307                 thread_unlock(newtd);
  308         }
  309         if (newtdp)
  310                 *newtdp = newtd;
  311         return 0;
  312 }
  313 
  314 void
  315 kthread_exit(void)
  316 {
  317         struct proc *p;
  318 
  319         /* A module may be waiting for us to exit. */
  320         wakeup(curthread);
  321 
  322         /*
  323          * We could rely on thread_exit to call exit1() but
  324          * there is extra work that needs to be done
  325          */
  326         if (curthread->td_proc->p_numthreads == 1)
  327                 kproc_exit(0);  /* never returns */
  328 
  329         p = curthread->td_proc;
  330         PROC_LOCK(p);
  331         PROC_SLOCK(p);
  332         thread_exit();
  333 }
  334 
  335 /*
  336  * Advise a kernel process to suspend (or resume) in its main loop.
  337  * Participation is voluntary.
  338  */
  339 int
  340 kthread_suspend(struct thread *td, int timo)
  341 {
  342         if ((td->td_pflags & TDP_KTHREAD) == 0) {
  343                 return (EINVAL);
  344         }
  345         thread_lock(td);
  346         td->td_flags |= TDF_KTH_SUSP;
  347         thread_unlock(td);
  348         /*
  349          * If it's stopped for some other reason,
  350          * kick it to notice our request 
  351          * or we'll end up timing out
  352          */
  353         wakeup(td); /* traditional  place for kernel threads to sleep on */ /* XXX ?? */
  354         return (tsleep(&td->td_flags, PPAUSE | PDROP, "suspkt", timo));
  355 }
  356 
  357 /*
  358  * let the kthread it can keep going again.
  359  */
  360 int
  361 kthread_resume(struct thread *td)
  362 {
  363         if ((td->td_pflags & TDP_KTHREAD) == 0) {
  364                 return (EINVAL);
  365         }
  366         thread_lock(td);
  367         td->td_flags &= ~TDF_KTH_SUSP;
  368         thread_unlock(td);
  369         wakeup(&td->td_name);
  370         return (0);
  371 }
  372 
  373 /*
  374  * Used by the thread to poll as to whether it should yield/sleep
  375  * and notify the caller that is has happened.
  376  */
  377 void
  378 kthread_suspend_check(struct thread *td)
  379 {
  380         while (td->td_flags & TDF_KTH_SUSP) {
  381                 /*
  382                  * let the caller know we got the message then sleep
  383                  */
  384                 wakeup(&td->td_flags);
  385                 tsleep(&td->td_name, PPAUSE, "ktsusp", 0);
  386         }
  387 }
  388 
  389 int
  390 kproc_kthread_add(void (*func)(void *), void *arg,
  391             struct proc **procptr, struct thread **tdptr,
  392             int flags, int pages, const char *procname, const char *fmt, ...) 
  393 {
  394         int error;
  395         va_list ap;
  396         char buf[100];
  397         struct thread *td;
  398 
  399         if (*procptr == 0) {
  400                 error = kproc_create(func, arg,
  401                         procptr, flags, pages, "%s", procname);
  402                 if (error)
  403                         return (error);
  404                 td = FIRST_THREAD_IN_PROC(*procptr);
  405                 if (tdptr)
  406                         *tdptr = td;
  407                 va_start(ap, fmt);
  408                 vsnprintf(td->td_name, sizeof(td->td_name), fmt, ap);
  409                 va_end(ap);
  410                 return (0); 
  411         }
  412         va_start(ap, fmt);
  413         vsnprintf(buf, sizeof(buf), fmt, ap);
  414         va_end(ap);
  415         error = kthread_add(func, arg, *procptr,
  416                     tdptr, flags, pages, "%s", buf);
  417         return (error);
  418 }

Cache object: f8490fbdb5beab6b8f07c9dbca243b37


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]


This page is part of the FreeBSD/Linux Linux Kernel Cross-Reference, and was automatically generated using a modified version of the LXR engine.