xnu-6153.81.5.tar.gz

[apple/xnu.git] / bsd / kern / kern_synch.c

diff --git a/bsd/kern/kern_synch.c b/bsd/kern/kern_synch.c
index 65765749022af01d67142d7545ac76ea6016e879..019952e736158c4cb0cc8062ec321448cdb6cac0 100644 (file)
--- a/bsd/kern/kern_synch.c
+++ b/bsd/kern/kern_synch.c
@@ -1,25 +1,31 @@
 /*
 /*

- * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 2000-2016 Apple Computer, Inc. All rights reserved.

  *
  *

- * @APPLE_LICENSE_HEADER_START@
- * 
- * The contents of this file constitute Original Code as defined in and
- * are subject to the Apple Public Source License Version 1.1 (the
- * "License").  You may not use this file except in compliance with the
- * License.  Please obtain a copy of the License at
- * http://www.apple.com/publicsource and read it before using this file.
- * 
- * This Original Code and all software distributed under the License are
- * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
+ *
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. The rights granted to you under the License
+ * may not be used to create, or enable the creation or redistribution of,
+ * unlawful or unlicensed copies of an Apple operating system, or to
+ * circumvent, violate, or enable the circumvention or violation of, any
+ * terms of an Apple operating system software license agreement.
+ *
+ * Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this file.
+ *
+ * The Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER

  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,

- * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
- * License for the specific language governing rights and limitations
- * under the License.
- * 
- * @APPLE_LICENSE_HEADER_END@
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
+ * limitations under the License.
+ *
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_END@

  */
  */

-/* 
+/*

  * Mach Operating System
  * Copyright (c) 1987 Carnegie-Mellon University
  * All rights reserved.  The CMU software License Agreement specifies
  * Mach Operating System
  * Copyright (c) 1987 Carnegie-Mellon University
  * All rights reserved.  The CMU software License Agreement specifies


@@ -28,18 +34,16 @@
 
 #include <sys/param.h>
 #include <sys/systm.h>
 
 #include <sys/param.h>
 #include <sys/systm.h>

-#include <sys/proc.h>
+#include <sys/proc_internal.h>

 #include <sys/user.h>
 #include <sys/user.h>

-#include <sys/file.h>
+#include <sys/file_internal.h>

 #include <sys/vnode.h>
 #include <sys/kernel.h>
 #include <sys/vnode.h>
 #include <sys/kernel.h>

-#include <sys/buf.h>
-
-#include <machine/spl.h>

 
 #include <kern/queue.h>
 #include <sys/lock.h>
 #include <kern/thread.h>
 
 #include <kern/queue.h>
 #include <sys/lock.h>
 #include <kern/thread.h>

+#include <kern/sched_prim.h>

 #include <kern/ast.h>
 
 #include <kern/cpu_number.h>
 #include <kern/ast.h>
 
 #include <kern/cpu_number.h>


@@ -47,65 +51,82 @@
 
 #include <kern/task.h>
 #include <mach/time_value.h>
 
 #include <kern/task.h>
 #include <mach/time_value.h>

+#include <kern/locks.h>
+#include <kern/policy_internal.h>
+
+#include <sys/systm.h>                  /* for unix_syscall_return() */
+#include <libkern/OSAtomic.h>

 
 

-_sleep_continue()
+extern void compute_averunnable(void *);        /* XXX */
+
+__attribute__((noreturn))
+static void
+_sleep_continue( __unused void *parameter, wait_result_t wresult)

 {
 {

-       register struct proc *p;
-       register thread_t thread = current_thread();
-       thread_act_t th_act;
+       struct proc *p = current_proc();
+       thread_t self  = current_thread();

        struct uthread * ut;
        int sig, catch;
        int error = 0;
        struct uthread * ut;
        int sig, catch;
        int error = 0;

+       int dropmutex, spinmutex;

 
 

-       th_act = current_act();
-       ut = get_bsdthread_info(th_act);
-       catch = ut->uu_pri & PCATCH;
-       p = current_proc();
+       ut = get_bsdthread_info(self);
+       catch     = ut->uu_pri & PCATCH;
+       dropmutex = ut->uu_pri & PDROP;
+       spinmutex = ut->uu_pri & PSPIN;

 
 

-#if FIXME  /* [ */
-       thread->wait_mesg = NULL;
-#endif  /* FIXME ] */
-       switch (get_thread_waitresult(thread)) {
-               case THREAD_TIMED_OUT:
-                       error = EWOULDBLOCK;
+       switch (wresult) {
+       case THREAD_TIMED_OUT:
+               error = EWOULDBLOCK;
+               break;
+       case THREAD_AWAKENED:
+               /*
+                * Posix implies any signal should be delivered
+                * first, regardless of whether awakened due
+                * to receiving event.
+                */
+               if (!catch) {

                        break;
                        break;

-               case THREAD_AWAKENED:
-                       /*
-                        * Posix implies any signal should be delivered
-                        * first, regardless of whether awakened due
-                        * to receiving event.
-                        */
-                       if (!catch)
-                               break;
-                       /* else fall through */
-               case THREAD_INTERRUPTED:
-                       if (catch) {
-                               unix_master();
-                               if (thread_should_abort(current_thread())) {
-                                       error = EINTR;
-                               } else if (SHOULDissignal(p,ut)) {
-                                       if (sig = CURSIG(p)) {
-                                               if (p->p_sigacts->ps_sigintr & sigmask(sig))
-                                                       error = EINTR;
-                                               else
-                                                       error = ERESTART;
-                                       }
-                                       if (thread_should_abort(current_thread())) {
+               }
+       /* else fall through */
+       case THREAD_INTERRUPTED:
+               if (catch) {
+                       if (thread_should_abort(self)) {
+                               error = EINTR;
+                       } else if (SHOULDissignal(p, ut)) {
+                               if ((sig = CURSIG(p)) != 0) {
+                                       if (p->p_sigacts->ps_sigintr & sigmask(sig)) {

                                                error = EINTR;
                                                error = EINTR;

+                                       } else {
+                                               error = ERESTART;

                                        }
                                }
                                        }
                                }

-                               unix_release();
-                       }  else
+                               if (thread_should_abort(self)) {
+                                       error = EINTR;
+                               }
+                       } else if ((ut->uu_flag & (UT_CANCELDISABLE | UT_CANCEL | UT_CANCELED)) == UT_CANCEL) {
+                               /* due to thread cancel */

                                error = EINTR;
                                error = EINTR;

-                       break;
+                       }
+               } else {
+                       error = EINTR;
+               }
+               break;

        }
 
        }
 

-       if ((error == EINTR) || (error == ERESTART)) {
-                       thread_ast_set(th_act, AST_BSD);
-                       ast_on(AST_BSD);
+       if (error == EINTR || error == ERESTART) {
+               act_set_astbsd(self);

        }
        }

-       if (ut->uu_timo)
-               thread_cancel_timer();
+
+       if (ut->uu_mtx && !dropmutex) {
+               if (spinmutex) {
+                       lck_mtx_lock_spin(ut->uu_mtx);
+               } else {
+                       lck_mtx_lock(ut->uu_mtx);
+               }
+       }
+       ut->uu_wchan = NULL;
+       ut->uu_wmesg = NULL;

 
        unix_syscall_return((*ut->uu_continuation)(error));
 }
 
        unix_syscall_return((*ut->uu_continuation)(error));
 }


@@ -122,217 +143,290 @@ _sleep_continue()
  * Callers of this routine must be prepared for
  * premature return, and check that the reason for
  * sleeping has gone away.
  * Callers of this routine must be prepared for
  * premature return, and check that the reason for
  * sleeping has gone away.

+ *
+ * if msleep was the entry point, than we have a mutex to deal with
+ *
+ * The mutex is unlocked before the caller is blocked, and
+ * relocked before msleep returns unless the priority includes the PDROP
+ * flag... if PDROP is specified, _sleep returns with the mutex unlocked
+ * regardless of whether it actually blocked or not.

  */
 
  */
 

-#if FIXME
-static __inline__
-#endif
-int
-_sleep(chan, pri, wmsg, timo, continuation, preassert)
-       caddr_t chan;
-       int pri;
-       char *wmsg;
-       int timo;
-       int (*continuation)();
-       int preassert;
+static int
+_sleep(
+       caddr_t         chan,
+       int             pri,
+       const char      *wmsg,
+       u_int64_t       abstime,
+       int             (*continuation)(int),
+       lck_mtx_t       *mtx)

 {
 {

-       register struct proc *p;
-       register thread_t thread = current_thread();
-       thread_act_t th_act;
+       struct proc *p;
+       thread_t self = current_thread();

        struct uthread * ut;
        struct uthread * ut;

-       int sig, catch = pri & PCATCH;
-       int sigttblock = pri & PTTYBLOCK;
+       int sig, catch;
+       int dropmutex  = pri & PDROP;
+       int spinmutex  = pri & PSPIN;
+       int wait_result;

        int error = 0;
        int error = 0;

-       spl_t   s;

 
 

-       s = splhigh();
+       ut = get_bsdthread_info(self);

 
 

-       th_act = current_act();
-       ut = get_bsdthread_info(th_act);
-       

        p = current_proc();
        p = current_proc();

-#if KTRACE
-       if (KTRPOINT(p, KTR_CSW))
-               ktrcsw(p->p_tracep, 1, 0);
-#endif 

        p->p_priority = pri & PRIMASK;
        p->p_priority = pri & PRIMASK;

-               
-       if (!preassert) {
-               /* it is already pre asserted */
-               if (chan)
-                       assert_wait(chan, (catch) ? THREAD_ABORTSAFE : THREAD_UNINT);
-               
+       /* It can still block in proc_exit() after the teardown. */
+       if (p->p_stats != NULL) {
+               OSIncrementAtomicLong(&p->p_stats->p_ru.ru_nvcsw);
+       }
+
+       if (pri & PCATCH) {
+               catch = THREAD_ABORTSAFE;
+       } else {
+               catch = THREAD_UNINT;

        }
        }

-       if (timo)
-               thread_set_timer(timo, NSEC_PER_SEC / hz);
-
-       /*
-        * We start our timeout
-        * before calling CURSIG, as we could stop there, and a wakeup
-        * or a SIGCONT (or both) could occur while we were stopped.
-        * A SIGCONT would cause us to be marked as SSLEEP
-        * without resuming us, thus we must be ready for sleep
-        * when CURSIG is called.  If the wakeup happens while we're
-        * stopped, p->p_wchan will be 0 upon return from CURSIG.
-        */
-       if (catch) {
-               unix_master();
-               if (SHOULDissignal(p,ut)) {
-                       if (sig = CURSIG(p)) {
-                               clear_wait(thread, THREAD_INTERRUPTED);
-                               /* if SIGTTOU or SIGTTIN then block till SIGCONT */
-                               if (sigttblock && ((sig == SIGTTOU) || (sig == SIGTTIN))) {
-                                       p->p_flag |= P_TTYSLEEP;
-                                       /* reset signal bits */
-                                       clear_sigbits(p, sig);
-                                       assert_wait(&p->p_siglist, THREAD_ABORTSAFE);
-                                       /* assert wait can block and SIGCONT should be checked */
-                                       if (p->p_flag & P_TTYSLEEP)
-                                               thread_block(0);
-                                       /* return with success */
-                                       error = 0;
+
+       /* set wait message & channel */
+       ut->uu_wchan = chan;
+       ut->uu_wmesg = wmsg ? wmsg : "unknown";
+
+       if (mtx != NULL && chan != NULL && (thread_continue_t)continuation == THREAD_CONTINUE_NULL) {
+               int     flags;
+
+               if (dropmutex) {
+                       flags = LCK_SLEEP_UNLOCK;
+               } else {
+                       flags = LCK_SLEEP_DEFAULT;
+               }
+
+               if (spinmutex) {
+                       flags |= LCK_SLEEP_SPIN;
+               }
+
+               if (abstime) {
+                       wait_result = lck_mtx_sleep_deadline(mtx, flags, chan, catch, abstime);
+               } else {
+                       wait_result = lck_mtx_sleep(mtx, flags, chan, catch);
+               }
+       } else {
+               if (chan != NULL) {
+                       assert_wait_deadline(chan, catch, abstime);
+               }
+               if (mtx) {
+                       lck_mtx_unlock(mtx);
+               }
+
+               if (catch == THREAD_ABORTSAFE) {
+                       if (SHOULDissignal(p, ut)) {
+                               if ((sig = CURSIG(p)) != 0) {
+                                       if (clear_wait(self, THREAD_INTERRUPTED) == KERN_FAILURE) {
+                                               goto block;
+                                       }
+                                       if (p->p_sigacts->ps_sigintr & sigmask(sig)) {
+                                               error = EINTR;
+                                       } else {
+                                               error = ERESTART;
+                                       }
+                                       if (mtx && !dropmutex) {
+                                               if (spinmutex) {
+                                                       lck_mtx_lock_spin(mtx);
+                                               } else {
+                                                       lck_mtx_lock(mtx);
+                                               }
+                                       }

                                        goto out;
                                }
                                        goto out;
                                }

-                               if (p->p_sigacts->ps_sigintr & sigmask(sig))
-                                       error = EINTR;
-                               else
-                                       error = ERESTART;
-                               unix_release();
+                       }
+                       if (thread_should_abort(self)) {
+                               if (clear_wait(self, THREAD_INTERRUPTED) == KERN_FAILURE) {
+                                       goto block;
+                               }
+                               error = EINTR;
+
+                               if (mtx && !dropmutex) {
+                                       if (spinmutex) {
+                                               lck_mtx_lock_spin(mtx);
+                                       } else {
+                                               lck_mtx_lock(mtx);
+                                       }
+                               }

                                goto out;
                        }
                }
                                goto out;
                        }
                }

-               if (thread_should_abort(current_thread())) {
-                       clear_wait(thread, THREAD_INTERRUPTED);
-                       error = EINTR;
-                       unix_release();
-                       goto out;
-               }
-               if (get_thread_waitevent(thread) == 0) {  /*already happened */
-                       unix_release();
-                       goto out;
+
+
+block:
+               if ((thread_continue_t)continuation != THREAD_CONTINUE_NULL) {
+                       ut->uu_continuation = continuation;
+                       ut->uu_pri  = pri;
+                       ut->uu_mtx  = mtx;
+                       (void) thread_block(_sleep_continue);
+                       /* NOTREACHED */

                }
                }

-               unix_release();
-       }

 
 

-#if FIXME  /* [ */
-       thread->wait_mesg = wmsg;
-#endif  /* FIXME ] */
-       splx(s);
-       p->p_stats->p_ru.ru_nvcsw++;
-
-       if (continuation != (int (*)()) 0 ) {
-         ut->uu_continuation = continuation;
-         ut->uu_pri = pri;
-         ut->uu_timo = timo;
-         thread_block(_sleep_continue);
-         /* NOTREACHED */
-       }
+               wait_result = thread_block(THREAD_CONTINUE_NULL);

 
 

-       thread_block(0);
+               if (mtx && !dropmutex) {
+                       if (spinmutex) {
+                               lck_mtx_lock_spin(mtx);
+                       } else {
+                               lck_mtx_lock(mtx);
+                       }
+               }
+       }

 
 

-#if FIXME  /* [ */
-       thread->wait_mesg = NULL;
-#endif  /* FIXME ] */
-       switch (get_thread_waitresult(thread)) {
-               case THREAD_TIMED_OUT:
-                       error = EWOULDBLOCK;
+       switch (wait_result) {
+       case THREAD_TIMED_OUT:
+               error = EWOULDBLOCK;
+               break;
+       case THREAD_AWAKENED:
+       case THREAD_RESTART:
+               /*
+                * Posix implies any signal should be delivered
+                * first, regardless of whether awakened due
+                * to receiving event.
+                */
+               if (catch != THREAD_ABORTSAFE) {

                        break;
                        break;

-               case THREAD_AWAKENED:
-                       /*
-                        * Posix implies any signal should be delivered
-                        * first, regardless of whether awakened due
-                        * to receiving event.
-                        */
-                       if (!catch)
-                               break;
-                       /* else fall through */
-               case THREAD_INTERRUPTED:
-                       if (catch) {
-                               unix_master();
-                               if (thread_should_abort(current_thread())) {
-                                       error = EINTR;
-                               } else if (SHOULDissignal(p,ut)) {
-                                       if (sig = CURSIG(p)) {
-                                               if (p->p_sigacts->ps_sigintr & sigmask(sig))
-                                                       error = EINTR;
-                                               else
-                                                       error = ERESTART;
-                                       }
-                                       if (thread_should_abort(current_thread())) {
+               }
+       /* else fall through */
+       case THREAD_INTERRUPTED:
+               if (catch == THREAD_ABORTSAFE) {
+                       if (thread_should_abort(self)) {
+                               error = EINTR;
+                       } else if (SHOULDissignal(p, ut)) {
+                               if ((sig = CURSIG(p)) != 0) {
+                                       if (p->p_sigacts->ps_sigintr & sigmask(sig)) {

                                                error = EINTR;
                                                error = EINTR;

+                                       } else {
+                                               error = ERESTART;

                                        }
                                }
                                        }
                                }

-                               unix_release();
-                       }  else
+                               if (thread_should_abort(self)) {
+                                       error = EINTR;
+                               }
+                       } else if ((ut->uu_flag & (UT_CANCELDISABLE | UT_CANCEL | UT_CANCELED)) == UT_CANCEL) {
+                               /* due to thread cancel */

                                error = EINTR;
                                error = EINTR;

-                       break;
+                       }
+               } else {
+                       error = EINTR;
+               }
+               break;

        }
 out:
        }
 out:

-       if ((error == EINTR) || (error == ERESTART)) {
-               thread_ast_set(th_act, AST_BSD);
-               ast_on(AST_BSD);
+       if (error == EINTR || error == ERESTART) {
+               act_set_astbsd(self);

        }
        }

-       if (timo)
-               thread_cancel_timer();
-       (void) splx(s);
-       return (error);
+       ut->uu_wchan = NULL;
+       ut->uu_wmesg = NULL;
+
+       return error;
+}
+
+int
+sleep(
+       void    *chan,
+       int             pri)
+{
+       return _sleep((caddr_t)chan, pri, (char *)NULL, 0, (int (*)(int))0, (lck_mtx_t *)0);
+}
+
+int
+msleep0(
+       void            *chan,
+       lck_mtx_t       *mtx,
+       int             pri,
+       const char      *wmsg,
+       int             timo,
+       int             (*continuation)(int))
+{
+       u_int64_t       abstime = 0;
+
+       if (timo) {
+               clock_interval_to_deadline(timo, NSEC_PER_SEC / hz, &abstime);
+       }
+
+       return _sleep((caddr_t)chan, pri, wmsg, abstime, continuation, mtx);

 }
 
 }
 

-int sleep(chan, pri)
-       void *chan;
-       int pri;
+int
+msleep(
+       void            *chan,
+       lck_mtx_t       *mtx,
+       int             pri,
+       const char      *wmsg,
+       struct timespec         *ts)

 {
 {

+       u_int64_t       abstime = 0;
+
+       if (ts && (ts->tv_sec || ts->tv_nsec)) {
+               nanoseconds_to_absolutetime((uint64_t)ts->tv_sec * NSEC_PER_SEC + ts->tv_nsec, &abstime );
+               clock_absolutetime_interval_to_deadline( abstime, &abstime );
+       }

 
 

-       return (_sleep((caddr_t)chan, pri, (char *)NULL, 0, (void (*)())0, 0));
-       
+       return _sleep((caddr_t)chan, pri, wmsg, abstime, (int (*)(int))0, mtx);

 }
 
 }
 

-int    tsleep(chan, pri, wmsg, timo)
-       void *chan;
-       int pri;
-       char * wmsg;
-       int     timo;
-{                      
-       return(_sleep((caddr_t)chan, pri, wmsg, timo, (void (*)())0, 0));
+int
+msleep1(
+       void            *chan,
+       lck_mtx_t       *mtx,
+       int             pri,
+       const char      *wmsg,
+       u_int64_t       abstime)
+{
+       return _sleep((caddr_t)chan, pri, wmsg, abstime, (int (*)(int))0, mtx);

 }
 
 }
 

-int    tsleep0(chan, pri, wmsg, timo, continuation)
-       void *chan;
-       int pri;
-       char * wmsg;
-       int     timo;
-       int (*continuation)();
-{                      
-#if defined (__i386__)
-       return(_sleep((caddr_t)chan, pri, wmsg, timo, (void (*)())0, 0));
-#else
-       return(_sleep((caddr_t)chan, pri, wmsg, timo, continuation, 0));
-#endif
+int
+tsleep(
+       void            *chan,
+       int             pri,
+       const char      *wmsg,
+       int             timo)
+{
+       u_int64_t       abstime = 0;
+
+       if (timo) {
+               clock_interval_to_deadline(timo, NSEC_PER_SEC / hz, &abstime);
+       }
+       return _sleep((caddr_t)chan, pri, wmsg, abstime, (int (*)(int))0, (lck_mtx_t *)0);

 }
 
 }
 

-/* tsleeps without assertwait or thread block */
-int    tsleep1(chan, pri, wmsg, timo, continuation)
-       void *chan;
-       int pri;
-       char * wmsg;
-       int     timo;
-       int (*continuation)();
-{                      
-#if defined (__i386__)
-       return(_sleep((caddr_t)chan, pri, wmsg, timo, (void (*)())0, 1));
-#else
-       return(_sleep((caddr_t)chan, pri, wmsg, timo, continuation, 1));
-#endif
+int
+tsleep0(
+       void            *chan,
+       int             pri,
+       const char      *wmsg,
+       int             timo,
+       int             (*continuation)(int))
+{
+       u_int64_t       abstime = 0;
+
+       if (timo) {
+               clock_interval_to_deadline(timo, NSEC_PER_SEC / hz, &abstime);
+       }
+       return _sleep((caddr_t)chan, pri, wmsg, abstime, continuation, (lck_mtx_t *)0);
+}
+
+int
+tsleep1(
+       void            *chan,
+       int             pri,
+       const char      *wmsg,
+       u_int64_t       abstime,
+       int             (*continuation)(int))
+{
+       return _sleep((caddr_t)chan, pri, wmsg, abstime, continuation, (lck_mtx_t *)0);

 }
 
 /*
  * Wake up all processes sleeping on chan.
  */
 void
 }
 
 /*
  * Wake up all processes sleeping on chan.
  */
 void

-wakeup(chan)
-       register void *chan;
+wakeup(void *chan)

 {
 {

-       thread_wakeup_prim((caddr_t)chan,FALSE, THREAD_AWAKENED);
+       thread_wakeup((caddr_t)chan);

 }
 
 /*
 }
 
 /*


@@ -341,10 +435,10 @@ wakeup(chan)
  * Be very sure that the first process is really
  * the right one to wakeup.
  */
  * Be very sure that the first process is really
  * the right one to wakeup.
  */

-wakeup_one(chan)
-       register caddr_t chan;
+void
+wakeup_one(caddr_t chan)

 {
 {

-       thread_wakeup_prim((caddr_t)chan, TRUE, THREAD_AWAKENED);
+       thread_wakeup_one((caddr_t)chan);

 }
 
 /*
 }
 
 /*


@@ -353,8 +447,32 @@ wakeup_one(chan)
  * than that of the current process.
  */
 void
  * than that of the current process.
  */
 void

-resetpriority(p)
-       register struct proc *p;
+resetpriority(struct proc *p)

 {
        (void)task_importance(p->task, -p->p_nice);
 }
 {
        (void)task_importance(p->task, -p->p_nice);
 }

+
+struct loadavg averunnable =
+{ {0, 0, 0}, FSCALE };                  /* load average, of runnable procs */
+/*
+ * Constants for averages over 1, 5, and 15 minutes
+ * when sampling at 5 second intervals.
+ */
+static fixpt_t cexp[3] = {
+       (fixpt_t)(0.9200444146293232 * FSCALE), /* exp(-1/12) */
+       (fixpt_t)(0.9834714538216174 * FSCALE), /* exp(-1/60) */
+       (fixpt_t)(0.9944598480048967 * FSCALE), /* exp(-1/180) */
+};
+
+void
+compute_averunnable(void *arg)
+{
+       unsigned int            nrun = *(unsigned int *)arg;
+       struct loadavg          *avg = &averunnable;
+       int             i;
+
+       for (i = 0; i < 3; i++) {
+               avg->ldavg[i] = (cexp[i] * avg->ldavg[i] +
+                   nrun * FSCALE * (FSCALE - cexp[i])) >> FSHIFT;
+       }
+}