Double resched_proc() in setrunnable()

[Martin Pieuchot]

Diff below moves resetpriority() out of updatepri() and resched_proc()
out of resetpriority() in order to expose a double resched_proc() call
in setrunnable().

This happens when a thread has slept for more than 1 second.  Since
p_usrpri is equal or bigger than p_priority, if the first call
triggers a need_resched() then the second will also do so.

I'd like to commit this diff which does not introduce any behavior
change then remove the first resched_proc() in setrunnable().

ok?

Index: kern/sched_bsd.c
===================================================================
RCS file: /cvs/src/sys/kern/sched_bsd.c,v
retrieving revision 1.43
diff -u -p -r1.43 sched_bsd.c
--- kern/sched_bsd.c    9 Mar 2016 13:38:50 -0000       1.43
+++ kern/sched_bsd.c    24 Mar 2016 11:37:34 -0000
@@ -246,6 +246,7 @@ schedcpu(void *arg)
                newcpu = (u_int) decay_cpu(loadfac, p->p_estcpu);
                p->p_estcpu = newcpu;
                resetpriority(p);
+               resched_proc(p, p->p_usrpri);
                if (p->p_priority >= PUSER) {
                        if (p->p_stat == SRUN &&
                            (p->p_priority / SCHED_PPQ) !=
@@ -284,7 +285,6 @@ updatepri(struct proc *p)
                        newcpu = (int) decay_cpu(loadfac, newcpu);
                p->p_estcpu = newcpu;
        }
-       resetpriority(p);
 }
 
 /*
@@ -454,7 +454,7 @@ mi_switch(void)
 #endif
 }
 
-static __inline void
+void
 resched_proc(struct proc *p, u_char pri)
 {
        struct cpu_info *ci;
@@ -509,8 +509,11 @@ setrunnable(struct proc *p)
        p->p_stat = SRUN;
        p->p_cpu = sched_choosecpu(p);
        setrunqueue(p);
-       if (p->p_slptime > 1)
+       if (p->p_slptime > 1) {
                updatepri(p);
+               resetpriority(p);
+               resched_proc(p, p->p_usrpri);
+       }
        p->p_slptime = 0;
        resched_proc(p, p->p_priority);
 }
@@ -531,7 +534,6 @@ resetpriority(struct proc *p)
            NICE_WEIGHT * (p->p_p->ps_nice - NZERO);
        newpriority = min(newpriority, MAXPRI);
        p->p_usrpri = newpriority;
-       resched_proc(p, p->p_usrpri);
 }
 
 /*
@@ -556,6 +558,7 @@ schedclock(struct proc *p)
        SCHED_LOCK(s);
        p->p_estcpu = ESTCPULIM(p->p_estcpu + 1);
        resetpriority(p);
+       resched_proc(p, p->p_usrpri);
        if (p->p_priority >= PUSER)
                p->p_priority = p->p_usrpri;
        SCHED_UNLOCK(s);
Index: kern/kern_resource.c
===================================================================
RCS file: /cvs/src/sys/kern/kern_resource.c,v
retrieving revision 1.55
diff -u -p -r1.55 kern_resource.c
--- kern/kern_resource.c        5 Dec 2015 10:11:53 -0000       1.55
+++ kern/kern_resource.c        24 Mar 2016 11:30:32 -0000
@@ -194,8 +194,10 @@ donice(struct proc *curp, struct process
                return (EACCES);
        chgpr->ps_nice = n;
        SCHED_LOCK(s);
-       TAILQ_FOREACH(p, &chgpr->ps_threads, p_thr_link)
-               (void)resetpriority(p);
+       TAILQ_FOREACH(p, &chgpr->ps_threads, p_thr_link) {
+               resetpriority(p);
+               resched_proc(p, p->p_usrpri);
+       }
        SCHED_UNLOCK(s);
        return (0);
 }
Index: sys/sched.h
===================================================================
RCS file: /cvs/src/sys/sys/sched.h,v
retrieving revision 1.41
diff -u -p -r1.41 sched.h
--- sys/sched.h 17 Mar 2016 13:18:47 -0000      1.41
+++ sys/sched.h 24 Mar 2016 11:35:38 -0000
@@ -166,6 +166,7 @@ void sched_stop_secondary_cpus(void);
 #define cpu_is_idle(ci)        ((ci)->ci_schedstate.spc_whichqs == 0)
 
 void sched_init_runqueues(void);
+void resched_proc(struct proc *p, u_char);
 void setrunqueue(struct proc *);
 void remrunqueue(struct proc *);