BSD 4_4 release

[unix-history] / usr / src / sys / kern / kern_synch.c

diff --git a/usr/src/sys/kern/kern_synch.c b/usr/src/sys/kern/kern_synch.c
index a2aaa90..609100b 100644 (file)
--- a/usr/src/sys/kern/kern_synch.c
+++ b/usr/src/sys/kern/kern_synch.c
@@ -1,32 +1,67 @@
-/*
- * Copyright (c) 1982, 1986 Regents of the University of California.
- * All rights reserved.  The Berkeley software License Agreement
- * specifies the terms and conditions for redistribution.
+/*-
+ * Copyright (c) 1982, 1986, 1990, 1991, 1993
+ *     The Regents of the University of California.  All rights reserved.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *     This product includes software developed by the University of
+ *     California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.

  *
  *

- *     @(#)kern_synch.c        7.9 (Berkeley) %G%
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *     @(#)kern_synch.c        8.1 (Berkeley) 6/10/93

  */
 
  */
 

-#include "machine/pte.h"
-#include "machine/psl.h"
-#include "machine/mtpr.h"
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/proc.h>
+#include <sys/kernel.h>
+#include <sys/buf.h>
+#include <sys/signalvar.h>
+#include <sys/resourcevar.h>
+#include <sys/vmmeter.h>
+#ifdef KTRACE
+#include <sys/ktrace.h>
+#endif

 
 

-#include "param.h"
-#include "systm.h"
-#include "user.h"
-#include "proc.h"
-#include "vm.h"
-#include "kernel.h"
-#include "buf.h"
+#include <machine/cpu.h>
+
+u_char curpri;                 /* usrpri of curproc */
+int    lbolt;                  /* once a second sleep address */

 
 /*
  * Force switch among equal priority processes every 100ms.
  */
 
 /*
  * Force switch among equal priority processes every 100ms.
  */

-roundrobin()
+/* ARGSUSED */
+void
+roundrobin(arg)
+       void *arg;

 {
 
 {
 

-       runrun++;
-       aston();
-       timeout(roundrobin, (caddr_t)0, hz / 10);
+       need_resched();
+       timeout(roundrobin, (void *)0, hz / 10);

 }
 
 /*
 }
 
 /*


@@ -79,7 +114,7 @@ roundrobin()
  *    Solve (factor)**(power) =~ .1 given power (5*loadav):
  *     solving for factor,
  *      ln(factor) =~ (-2.30/5*loadav), or
  *    Solve (factor)**(power) =~ .1 given power (5*loadav):
  *     solving for factor,
  *      ln(factor) =~ (-2.30/5*loadav), or

- *      factor =~ exp(-1/((5/2.30)*loadav) =~ exp(-1/(2*loadav)) =
+ *      factor =~ exp(-1/((5/2.30)*loadav)) =~ exp(-1/(2*loadav)) =

  *          exp(-1/b) =~ (b-1)/b =~ b/(b+1).                    QED
  *
  * Proof of (2):
  *          exp(-1/b) =~ (b-1)/b =~ b/(b+1).                    QED
  *
  * Proof of (2):


@@ -94,8 +129,8 @@ roundrobin()
  */
 
 /* calculations for digital decay to forget 90% of usage in 5*loadav sec */
  */
 
 /* calculations for digital decay to forget 90% of usage in 5*loadav sec */

-#define        get_b(loadav)           (2 * (loadav))
-#define        get_pcpu(b, cpu)        (((b) * ((cpu) & 0377)) / ((b) + FSCALE))
+#define        loadfactor(loadav)      (2 * (loadav))
+#define        decay_cpu(loadfac, cpu) (((loadfac) * (cpu)) / ((loadfac) + FSCALE))

 
 /* decay 95% of `p_pctcpu' in 60 seconds; see CCPU_SHIFT before changing */
 fixpt_t        ccpu = 0.95122942450071400909 * FSCALE;         /* exp(-1/20) */
 
 /* decay 95% of `p_pctcpu' in 60 seconds; see CCPU_SHIFT before changing */
 fixpt_t        ccpu = 0.95122942450071400909 * FSCALE;         /* exp(-1/20) */


@@ -117,19 +152,26 @@ fixpt_t   ccpu = 0.95122942450071400909 * FSCALE;         /* exp(-1/20) */
 /*
  * Recompute process priorities, once a second
  */
 /*
  * Recompute process priorities, once a second
  */

-schedcpu()
+/* ARGSUSED */
+void
+schedcpu(arg)
+       void *arg;

 {
 {

-       register fixpt_t b = get_b(averunnable[0]);
+       register fixpt_t loadfac = loadfactor(averunnable.ldavg[0]);

        register struct proc *p;
        register struct proc *p;

-       register int s, a;
+       register int s;
+       register unsigned int newcpu;

 
        wakeup((caddr_t)&lbolt);
 
        wakeup((caddr_t)&lbolt);

-       for (p = allproc; p != NULL; p = p->p_nxt) {
-               if (p->p_time != 127)
-                       p->p_time++;
-               if (p->p_stat==SSLEEP || p->p_stat==SSTOP)
-                       if (p->p_slptime != 127)
-                               p->p_slptime++;
+       for (p = (struct proc *)allproc; p != NULL; p = p->p_nxt) {
+               /*
+                * Increment time in/out of memory and sleep time
+                * (if sleeping).  We ignore overflow; with 16-bit int's
+                * (remember them?) overflow takes 45 days.
+                */
+               p->p_time++;
+               if (p->p_stat == SSLEEP || p->p_stat == SSTOP)
+                       p->p_slptime++;

                p->p_pctcpu = (p->p_pctcpu * ccpu) >> FSHIFT;
                /*
                 * If the process has slept the entire second,
                p->p_pctcpu = (p->p_pctcpu * ccpu) >> FSHIFT;
                /*
                 * If the process has slept the entire second,


@@ -137,6 +179,7 @@ schedcpu()
                 */
                if (p->p_slptime > 1)
                        continue;
                 */
                if (p->p_slptime > 1)
                        continue;

+               s = splstatclock();     /* prevent state changes */

                /*
                 * p_pctcpu is only for ps.
                 */
                /*
                 * p_pctcpu is only for ps.
                 */


@@ -150,17 +193,12 @@ schedcpu()
                        (p->p_cpticks * FSCALE / hz)) >> FSHIFT;
 #endif
                p->p_cpticks = 0;
                        (p->p_cpticks * FSCALE / hz)) >> FSHIFT;
 #endif
                p->p_cpticks = 0;

-               a = (int) get_pcpu(b, p->p_cpu) + p->p_nice;
-               if (a < 0)
-                       a = 0;
-               if (a > 255)
-                       a = 255;
-               p->p_cpu = a;
-               (void) setpri(p);
-               s = splhigh();  /* prevent state changes */
+               newcpu = (u_int) decay_cpu(loadfac, p->p_cpu) + p->p_nice;
+               p->p_cpu = min(newcpu, UCHAR_MAX);
+               setpri(p);

                if (p->p_pri >= PUSER) {
                if (p->p_pri >= PUSER) {

-#define        PPQ     (128 / NQS)
-                       if ((p != u.u_procp || noproc) &&
+#define        PPQ     (128 / NQS)             /* priorities per queue */
+                       if ((p != curproc) &&

                            p->p_stat == SRUN &&
                            (p->p_flag & SLOAD) &&
                            (p->p_pri / PPQ) != (p->p_usrpri / PPQ)) {
                            p->p_stat == SRUN &&
                            (p->p_flag & SLOAD) &&
                            (p->p_pri / PPQ) != (p->p_usrpri / PPQ)) {


@@ -173,34 +211,32 @@ schedcpu()
                splx(s);
        }
        vmmeter();
                splx(s);
        }
        vmmeter();

-       if (runin!=0) {
-               runin = 0;
-               wakeup((caddr_t)&runin);
-       }

        if (bclnlist != NULL)
        if (bclnlist != NULL)

-               wakeup((caddr_t)&proc[2]);
-       timeout(schedcpu, (caddr_t)0, hz);
+               wakeup((caddr_t)pageproc);
+       timeout(schedcpu, (void *)0, hz);

 }
 
 /*
  * Recalculate the priority of a process after it has slept for a while.
 }
 
 /*
  * Recalculate the priority of a process after it has slept for a while.

+ * For all load averages >= 1 and max p_cpu of 255, sleeping for at least
+ * six times the loadfactor will decay p_cpu to zero.

  */
  */

+void

 updatepri(p)
        register struct proc *p;
 {
 updatepri(p)
        register struct proc *p;
 {

-       register int a = p->p_cpu & 0377;
-       register fixpt_t b = get_b(averunnable[0]);
+       register unsigned int newcpu = p->p_cpu;
+       register fixpt_t loadfac = loadfactor(averunnable.ldavg[0]);

 
 

-       p->p_slptime--;         /* the first time was done in schedcpu */
-       while (a && --p->p_slptime)
-               a = (int) get_pcpu(b, a) /* + p->p_nice */;
-       p->p_slptime = 0;
-       if (a < 0)
-               a = 0;
-       if (a > 255)
-               a = 255;
-       p->p_cpu = a;
-       (void) setpri(p);
+       if (p->p_slptime > 5 * loadfac)
+               p->p_cpu = 0;
+       else {
+               p->p_slptime--; /* the first time was done in schedcpu */
+               while (newcpu && --p->p_slptime)
+                       newcpu = (int) decay_cpu(loadfac, newcpu);
+               p->p_cpu = min(newcpu, UCHAR_MAX);
+       }
+       setpri(p);

 }
 
 #define SQSIZE 0100    /* Must be power of 2 */
 }
 
 #define SQSIZE 0100    /* Must be power of 2 */


@@ -211,26 +247,47 @@ struct slpque {
 } slpque[SQSIZE];
 
 /*
 } slpque[SQSIZE];
 
 /*

- * Give up the processor till a wakeup occurs
- * on chan, at which time the process
- * enters the scheduling queue at priority pri.
- * The most important effect of pri is that when
- * pri<=PZERO a signal cannot disturb the sleep;
- * if pri>PZERO signals will be processed.
- * Callers of this routine must be prepared for
- * premature return, and check that the reason for
- * sleeping has gone away.
+ * During autoconfiguration or after a panic, a sleep will simply
+ * lower the priority briefly to allow interrupts, then return.
+ * The priority to be used (safepri) is machine-dependent, thus this
+ * value is initialized and maintained in the machine-dependent layers.
+ * This priority will typically be 0, or the lowest priority
+ * that is safe for use on the interrupt stack; it can be made
+ * higher to block network software interrupts after panics.

  */
  */

-sleep(chan, pri)
-       caddr_t chan;
+int safepri;
+
+/*
+ * General sleep call.
+ * Suspends current process until a wakeup is made on chan.
+ * The process will then be made runnable with priority pri.
+ * Sleeps at most timo/hz seconds (0 means no timeout).
+ * If pri includes PCATCH flag, signals are checked
+ * before and after sleeping, else signals are not checked.
+ * Returns 0 if awakened, EWOULDBLOCK if the timeout expires.
+ * If PCATCH is set and a signal needs to be delivered,
+ * ERESTART is returned if the current system call should be restarted
+ * if possible, and EINTR is returned if the system call should
+ * be interrupted by the signal (return EINTR).
+ */
+int
+tsleep(chan, pri, wmesg, timo)
+       void *chan;

        int pri;
        int pri;

+       char *wmesg;
+       int timo;

 {
 {

-       register struct proc *rp;
+       register struct proc *p = curproc;

        register struct slpque *qp;
        register s;
        register struct slpque *qp;
        register s;

+       int sig, catch = pri & PCATCH;

        extern int cold;
        extern int cold;

+       void endtsleep __P((void *));

 
 

-       rp = u.u_procp;
+#ifdef KTRACE
+       if (KTRPOINT(p, KTR_CSW))
+               ktrcsw(p->p_tracep, 1, 0);
+#endif

        s = splhigh();
        if (cold || panicstr) {
                /*
        s = splhigh();
        if (cold || panicstr) {
                /*


@@ -238,69 +295,174 @@ sleep(chan, pri)
                 * just give interrupts a chance, then just return;
                 * don't run any other procs or panic below,
                 * in case this is the idle process and already asleep.
                 * just give interrupts a chance, then just return;
                 * don't run any other procs or panic below,
                 * in case this is the idle process and already asleep.

-                * The splnet should be spl0 if the network was being used
-                * by the filesystem, but for now avoid network interrupts
-                * that might cause another panic.

                 */
                 */

-               (void) splnet();
+               splx(safepri);

                splx(s);
                splx(s);

-               return;
+               return (0);

        }
        }

-       if (chan==0 || rp->p_stat != SRUN || rp->p_rlink)
-               panic("sleep");
-       rp->p_wchan = chan;
-       rp->p_slptime = 0;
-       rp->p_pri = pri;
+#ifdef DIAGNOSTIC
+       if (chan == NULL || p->p_stat != SRUN || p->p_rlink)
+               panic("tsleep");
+#endif
+       p->p_wchan = chan;
+       p->p_wmesg = wmesg;
+       p->p_slptime = 0;
+       p->p_pri = pri & PRIMASK;

        qp = &slpque[HASH(chan)];
        if (qp->sq_head == 0)
        qp = &slpque[HASH(chan)];
        if (qp->sq_head == 0)

-               qp->sq_head = rp;
+               qp->sq_head = p;

        else
        else

-               *qp->sq_tailp = rp;
-       *(qp->sq_tailp = &rp->p_link) = 0;
+               *qp->sq_tailp = p;
+       *(qp->sq_tailp = &p->p_link) = 0;
+       if (timo)
+               timeout(endtsleep, (void *)p, timo);
+       /*
+        * We put ourselves on the sleep queue and 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) {
+               p->p_flag |= SSINTR;
+               if (sig = CURSIG(p)) {
+                       if (p->p_wchan)
+                               unsleep(p);
+                       p->p_stat = SRUN;
+                       goto resume;
+               }
+               if (p->p_wchan == 0) {
+                       catch = 0;
+                       goto resume;
+               }
+       } else
+               sig = 0;
+       p->p_stat = SSLEEP;
+       p->p_stats->p_ru.ru_nvcsw++;
+       swtch();
+resume:
+       curpri = p->p_usrpri;
+       splx(s);
+       p->p_flag &= ~SSINTR;
+       if (p->p_flag & STIMO) {
+               p->p_flag &= ~STIMO;
+               if (sig == 0) {
+#ifdef KTRACE
+                       if (KTRPOINT(p, KTR_CSW))
+                               ktrcsw(p->p_tracep, 0, 0);
+#endif
+                       return (EWOULDBLOCK);
+               }
+       } else if (timo)
+               untimeout(endtsleep, (void *)p);
+       if (catch && (sig != 0 || (sig = CURSIG(p)))) {
+#ifdef KTRACE
+               if (KTRPOINT(p, KTR_CSW))
+                       ktrcsw(p->p_tracep, 0, 0);
+#endif
+               if (p->p_sigacts->ps_sigintr & sigmask(sig))
+                       return (EINTR);
+               return (ERESTART);
+       }
+#ifdef KTRACE
+       if (KTRPOINT(p, KTR_CSW))
+               ktrcsw(p->p_tracep, 0, 0);
+#endif
+       return (0);
+}
+
+/*
+ * Implement timeout for tsleep.
+ * If process hasn't been awakened (wchan non-zero),
+ * set timeout flag and undo the sleep.  If proc
+ * is stopped, just unsleep so it will remain stopped.
+ */
+void
+endtsleep(arg)
+       void *arg;
+{
+       register struct proc *p;
+       int s;
+
+       p = (struct proc *)arg;
+       s = splhigh();
+       if (p->p_wchan) {
+               if (p->p_stat == SSLEEP)
+                       setrun(p);
+               else
+                       unsleep(p);
+               p->p_flag |= STIMO;
+       }
+       splx(s);
+}
+
+/*
+ * Short-term, non-interruptable sleep.
+ */
+void
+sleep(chan, pri)
+       void *chan;
+       int pri;
+{
+       register struct proc *p = curproc;
+       register struct slpque *qp;
+       register s;
+       extern int cold;
+
+#ifdef DIAGNOSTIC

        if (pri > PZERO) {
        if (pri > PZERO) {

+               printf("sleep called with pri %d > PZERO, wchan: %x\n",
+                   pri, chan);
+               panic("old sleep");
+       }
+#endif
+       s = splhigh();
+       if (cold || panicstr) {

                /*
                /*

-                * If we stop in issig(), wakeup may already have happened
-                * when we return (rp->p_wchan will then be 0).
+                * After a panic, or during autoconfiguration,
+                * just give interrupts a chance, then just return;
+                * don't run any other procs or panic below,
+                * in case this is the idle process and already asleep.

                 */
                 */

-               if (ISSIG(rp)) {
-                       if (rp->p_wchan)
-                               unsleep(rp);
-                       rp->p_stat = SRUN;
-                       (void) spl0();
-                       goto psig;
-               }
-               if (rp->p_wchan == 0)
-                       goto out;
-               rp->p_stat = SSLEEP;
-               (void) spl0();
-               u.u_ru.ru_nvcsw++;
-               swtch();
-               if (ISSIG(rp))
-                       goto psig;
-       } else {
-               rp->p_stat = SSLEEP;
-               (void) spl0();
-               u.u_ru.ru_nvcsw++;
-               swtch();
+               splx(safepri);
+               splx(s);
+               return;

        }
        }

-       curpri = rp->p_usrpri;
-out:
+#ifdef DIAGNOSTIC
+       if (chan == NULL || p->p_stat != SRUN || p->p_rlink)
+               panic("sleep");
+#endif
+       p->p_wchan = chan;
+       p->p_wmesg = NULL;
+       p->p_slptime = 0;
+       p->p_pri = pri;
+       qp = &slpque[HASH(chan)];
+       if (qp->sq_head == 0)
+               qp->sq_head = p;
+       else
+               *qp->sq_tailp = p;
+       *(qp->sq_tailp = &p->p_link) = 0;
+       p->p_stat = SSLEEP;
+       p->p_stats->p_ru.ru_nvcsw++;
+#ifdef KTRACE
+       if (KTRPOINT(p, KTR_CSW))
+               ktrcsw(p->p_tracep, 1, 0);
+#endif
+       swtch();
+#ifdef KTRACE
+       if (KTRPOINT(p, KTR_CSW))
+               ktrcsw(p->p_tracep, 0, 0);
+#endif
+       curpri = p->p_usrpri;

        splx(s);
        splx(s);

-       return;
-
-       /*
-        * If priority was low (>PZERO) and
-        * there has been a signal, execute non-local goto through
-        * u.u_qsave, aborting the system call in progress (see trap.c)
-        */
-psig:
-       longjmp(&u.u_qsave);
-       /*NOTREACHED*/

 }
 
 /*
  * Remove a process from its wait queue
  */
 }
 
 /*
  * Remove a process from its wait queue
  */

+void

 unsleep(p)
        register struct proc *p;
 {
 unsleep(p)
        register struct proc *p;
 {


@@ -322,10 +484,12 @@ unsleep(p)
 }
 
 /*
 }
 
 /*

- * Wake up all processes sleeping on chan.
+ * Wakeup on "chan"; set all processes
+ * sleeping on chan to run state.

  */
  */

+void

 wakeup(chan)
 wakeup(chan)

-       register caddr_t chan;
+       register void *chan;

 {
        register struct slpque *qp;
        register struct proc *p, **q;
 {
        register struct slpque *qp;
        register struct proc *p, **q;


@@ -335,9 +499,11 @@ wakeup(chan)
        qp = &slpque[HASH(chan)];
 restart:
        for (q = &qp->sq_head; p = *q; ) {
        qp = &slpque[HASH(chan)];
 restart:
        for (q = &qp->sq_head; p = *q; ) {

+#ifdef DIAGNOSTIC

                if (p->p_rlink || p->p_stat != SSLEEP && p->p_stat != SSTOP)
                        panic("wakeup");
                if (p->p_rlink || p->p_stat != SSLEEP && p->p_stat != SSTOP)
                        panic("wakeup");

-               if (p->p_wchan==chan) {
+#endif
+               if (p->p_wchan == chan) {

                        p->p_wchan = 0;
                        *q = p->p_link;
                        if (qp->sq_tailp == &p->p_link)
                        p->p_wchan = 0;
                        *q = p->p_link;
                        if (qp->sq_tailp == &p->p_link)


@@ -346,6 +512,7 @@ restart:
                                /* OPTIMIZED INLINE EXPANSION OF setrun(p) */
                                if (p->p_slptime > 1)
                                        updatepri(p);
                                /* OPTIMIZED INLINE EXPANSION OF setrun(p) */
                                if (p->p_slptime > 1)
                                        updatepri(p);

+                               p->p_slptime = 0;

                                p->p_stat = SRUN;
                                if (p->p_flag & SLOAD)
                                        setrq(p);
                                p->p_stat = SRUN;
                                if (p->p_flag & SLOAD)
                                        setrq(p);


@@ -353,15 +520,10 @@ restart:
                                 * Since curpri is a usrpri,
                                 * p->p_pri is always better than curpri.
                                 */
                                 * Since curpri is a usrpri,
                                 * p->p_pri is always better than curpri.
                                 */

-                               runrun++;
-                               aston();
-                               if ((p->p_flag&SLOAD) == 0) {
-                                       if (runout != 0) {
-                                               runout = 0;
-                                               wakeup((caddr_t)&runout);
-                                       }
-                                       wantin++;
-                               }
+                               if ((p->p_flag&SLOAD) == 0)
+                                       wakeup((caddr_t)&proc0);
+                               else
+                                       need_resched();

                                /* END INLINE EXPANSION */
                                goto restart;
                        }
                                /* END INLINE EXPANSION */
                                goto restart;
                        }


@@ -371,6 +533,63 @@ restart:
        splx(s);
 }
 
        splx(s);
 }
 

+/*
+ * The machine independent parts of swtch().
+ * Must be called at splstatclock() or higher.
+ */
+void
+swtch()
+{
+       register struct proc *p = curproc;      /* XXX */
+       register struct rlimit *rlim;
+       register long s, u;
+       struct timeval tv;
+
+       /*
+        * Compute the amount of time during which the current
+        * process was running, and add that to its total so far.
+        */
+       microtime(&tv);
+       u = p->p_rtime.tv_usec + (tv.tv_usec - runtime.tv_usec);
+       s = p->p_rtime.tv_sec + (tv.tv_sec - runtime.tv_sec);
+       if (u < 0) {
+               u += 1000000;
+               s--;
+       } else if (u >= 1000000) {
+               u -= 1000000;
+               s++;
+       }
+       p->p_rtime.tv_usec = u;
+       p->p_rtime.tv_sec = s;
+
+       /*
+        * Check if the process exceeds its cpu resource allocation.
+        * If over max, kill it.  In any case, if it has run for more
+        * than 10 minutes, reduce priority to give others a chance.
+        */
+       rlim = &p->p_rlimit[RLIMIT_CPU];
+       if (s >= rlim->rlim_cur) {
+               if (s >= rlim->rlim_max)
+                       psignal(p, SIGKILL);
+               else {
+                       psignal(p, SIGXCPU);
+                       if (rlim->rlim_cur < rlim->rlim_max)
+                               rlim->rlim_cur += 5;
+               }
+       }
+       if (s > 10 * 60 && p->p_ucred->cr_uid && p->p_nice == NZERO) {
+               p->p_nice = NZERO + 4;
+               setpri(p);
+       }
+
+       /*
+        * Pick a new current process and record its start time.
+        */
+       cnt.v_swtch++;
+       cpu_swtch(p);
+       microtime(&runtime);
+}
+

 /*
  * Initialize the (doubly-linked) run queues
  * to be empty.
 /*
  * Initialize the (doubly-linked) run queues
  * to be empty.


@@ -384,9 +603,11 @@ rqinit()
 }
 
 /*
 }
 
 /*

- * Set the process running;
- * arrange for it to be swapped in if necessary.
+ * Change process state to be runnable,
+ * placing it on the run queue if it is in memory,
+ * and awakening the swapper if it isn't in memory.

  */
  */

+void

 setrun(p)
        register struct proc *p;
 {
 setrun(p)
        register struct proc *p;
 {


@@ -416,40 +637,27 @@ setrun(p)
        splx(s);
        if (p->p_slptime > 1)
                updatepri(p);
        splx(s);
        if (p->p_slptime > 1)
                updatepri(p);

-       if (p->p_pri < curpri) {
-               runrun++;
-               aston();
-       }
-       if ((p->p_flag&SLOAD) == 0) {
-               if (runout != 0) {
-                       runout = 0;
-                       wakeup((caddr_t)&runout);
-               }
-               wantin++;
-       }
+       p->p_slptime = 0;
+       if ((p->p_flag&SLOAD) == 0)
+               wakeup((caddr_t)&proc0);
+       else if (p->p_pri < curpri)
+               need_resched();

 }
 
 /*
 }
 
 /*

- * Set user priority.
- * The rescheduling flag (runrun)
- * is set if the priority is better
- * than the currently running process.
+ * Compute priority of process when running in user mode.
+ * Arrange to reschedule if the resulting priority
+ * is better than that of the current process.

  */
  */

-setpri(pp)
-       register struct proc *pp;
+void
+setpri(p)
+       register struct proc *p;

 {
 {

-       register int p;
-
-       p = (pp->p_cpu & 0377)/4;
-       p += PUSER + 2 * pp->p_nice;
-       if (pp->p_rssize > pp->p_maxrss && freemem < desfree)
-               p += 2*4;       /* effectively, nice(4) */
-       if (p > 127)
-               p = 127;
-       if (p < curpri) {
-               runrun++;
-               aston();
-       }
-       pp->p_usrpri = p;
-       return (p);
+       register unsigned int newpri;
+
+       newpri = PUSER + p->p_cpu / 4 + 2 * p->p_nice;
+       newpri = min(newpri, MAXPRI);
+       p->p_usrpri = newpri;
+       if (newpri < curpri)
+               need_resched();

 }
 }